Software & Systems

Articles of journal № 2 at 2015 year.

Order result by: Public date | Title | Authors

1. Web-oriented component of an expert system [№2 за 2015 год]
Authors: Korshunov S.A., Pavlov A.I., Nikolaychuk O.A.
Visitors: 12539
The paper discusses problems of expert system component implementation in the form of a web application. This component will allow the experts to solve problems using formed logical rules describing the dynamics of studied pro-cesses. Web-based access to the component will enable public access which is especially important in interdisciplinary stud-ies that require a team work of specialists from different areas of expertise. The component has the following architecture: web-service; module interacting with the database and implementing the programming interface to access the database; knowledge management module for working with the rules and facts; rules editor based on RVML-notation; module of communication with web-service that implements the user interface access to the expert system web-service; database for knowledge base storage (facts, rules and initial conditions). The implementation of the web-service is considered in detail. The paper mentions a description of its functions, architecture and functional modules. The main task of a web-service is to prepare database information (facts and rules) for further processing by engine, i.e. convert it from the generalized form to JESS format. The obtained information will be used to implement inference based on rules and facts. The main modules of web-service are: database interface that implements a software interface to access the database; an inference engine that i m-plements the process of reasoning according to the rules and is presented in the form of a software library imp lementing the JESS engine; conversion unit of the rules and facts from the generalized to engine format, the implementation depends on the engine.

2. The architecture of a smart home management system integrated into the сloud environment [№2 за 2015 год]
Author: Nikolaev P.L.
Visitors: 10743
The article describes a flexible architecture of a smart home management system integrated into the cloud en-vironment. This cloud environment provides users with the infrastructure for remote control actuators and for monitoring and processing of data from different sensors that form the system of smart home. The paper presents the benefits for end users from integration of their smart houses into the cloud. The remote control is possible with mobile and stationary devices either via Internet or home LAN. The presented architecture corresponds to the concept of the “Internet of things”. The article pre-sents the typical hardware architecture of a smart home management system consisting of three levels of automation. Then the author offers the hardware scheme of a smart home management system integrated into the cloud and consisting of five levels of automation. The paper describes in detail all components of a smart home management system (the cloud server, the home server, the controller, control devices and terminal equipment) and ways of their interaction with each other. In addi-tion to the hardware component of the smart home management system architecture, the article also considers its software. For the interaction of control devices, cloud and home servers it is is necessary to apply web-services technology. The carried out analysis has revealed that the preferable option is to use a RESTful web service: a request and data transmission are car-ried in JSON via HTTP-requests (GET and POST). This paper also provides the execution algorithm of remote management function for smart home system.

3. On distance metric for the system of automatic classification of the eee devices by production batches [№2 за 2015 год]
Authors: Kazakovtsev L.A., Stupina A.A., Orlov V.I.
Visitors: 8236
Packaging electronic units of complex technical systems with high quality electronic components is an essential condition of increasing quality of the whole system. Elements of the same type should have equal characteristics, which is achieved if they are produced as one produc-tion batch from a one batch of raw materials. Electronic units vary in the requirements concerning the number of pr o-duction batches of devices. This article considers the problem of discovering the quantity of the production ba tches in a lot shipped by a supplier of electronic devices based on testing results as a problem of cluster analysis. The authors propose using the rectangular metric in the k-means clustering problem. They also show the necessary modification of a local search procedure. The results of running system of EEE devices automatic classification by production batches are given. Such results are provided for a k-median problem with squared Euclidean and rectangular metrics. Tests da-ta of the electronic chips were used as example data. Data dimension is up to 2500 data vectors, each of them contains the results of measurement that are up to 230 parameters. An MDS method (Multidimensional Scaling) was used for visual representation of the multidimensional vectors classification results.

4. A genetic algorithm for computer-aided design of preparatory forging transitions [№2 за 2015 год]
Authors: Kanyukov S.I., Konovalov A.V.
Visitors: 9910
The experience of development and implementation of forging CAPP for different types of hammer and press forgings shows that a considerable part in the list of problems to be solved during computer-aided design is so-called difficult-to-formalize problems. An ex-perienced technologist solves these problems under conditions of noncomputerized designing fairly easily, but CAPP developers have to complement the systems by approximation algorithms and offer users-technologists to make their corrections in solutions obtained in an ac-tive dialogue. This approach supposes that technologist’s production experience is used by systems only in a specific version of a design and is not extended to other versions. At the same time the generated database of technological processes previously designed wit h or without human participation implicitly reflects technologists' production experience and the specific character of forging production at an enterprise. The problem is to use this information when solving the tasks which are difficult to formalize. The application of ideas and methods of the genetic algorithm theory which allow a system to use the experience of previous decisions and to develop itself on this basis while in use seems promising in this case. The paper describes a genetic algorithm developed to solve the problem of designing preparatory transitions in a CAPP system of shaft press-forging. This algorithm has the properties of self-improvement and auto-adjustment to actual manufacturing conditions. This allows saving CAPP users from the necessity of making numerous corrections in the design outputs. The abovementioned approach to the development of genetic algorithms can be applied to solving other difficult-to-formalize tasks of forging design.

5. Dynamic structures in relational databases [№2 за 2015 год]
Author: A.A. Poltavtsev
Visitors: 7522
There is a set of problems in the development of applications for work with databases. The principal cause of these problems is in non-optimized SQL queries and stored procedures. To achieve good productivity, it is necessary to make SQL queries correctly, create (or delete) additional indexes, denormalize a database (in certain cases), shift a part of logic on triggers and stored procedures. It is necessary to maintain agreed algorithms structuring methods, structuring methods of data used in these algorithms and structuring methods (storage schemes construction) for these data in databases based on a rel a-tional model. This paper is devoted to generation and a manipulation data structures in relational databases whose compo-nents in programming languages are connected by explicit indexes. The author considers a specific, rather simple data stru c-ture. It is a linear unidirectional coherent list. Lists as trees are among the most basic data models used in computer programs. In a sense, lists are simple forms of trees because one can think of a list as a binary tree where every left child is a leaf. How-ever, lists also present some aspects that are not special cases of what we have learned about trees. For instance, we shall talk about operations on lists such as pushing and popping that have no common analog for trees.

6. Information support system of fuzzy evaluation and consistent optimization [№2 за 2015 год]
Authors: Veselkov A.N., Kuznetsov V.N., Doropey V.N.
Visitors: 8766
Enterprise management is considered as a serial or network decision-making process in fuzzy condi-tions. People operate with fuzzy concepts and fuzzy instr uctions. Fuzziness is the main source of uncertainty in the process of coordinated optimization. People use fuzzy concepts and perform fuzzy instructions when making dec i-sions. In addition, in many cases they have different opinions on specific problems an d ways to solve them. In activi-ties, people tend to operate with vague concepts and perform vague instructions. Fuzzy sets and approach to decision -making in fuzzy conditions allows creating a decision support system for information technology such as "1C: Enter-prise 8.3". A decision-making group makes decisions. This group consists of the Center (operation researcher), who is respon-sible for making decisions for the entire enterprise, and agents, who make decisions for their units. The Center and agents are users of a local network for group decision-making support. If the Center solves the problem of optimal so-lutions on the basis of interests, this solution, in general, cannot be optimal for the elements. Elements in accordance with their interests will distort the information provided to the Center, or will not use the information system. To avoid that, the Center should provide the elements with solutions, which are favorable to them. But to do this for the Cent er and agents at the same time is not always possible. Therefore it is better to apply consistent optimization solutions. A method of system analysis for decision-making to create an electronic document management system is based on the consistent control principle and the rules of consistent planning; it includes heuristic procedures and fuzzy logic.

7. An experimental study of the performance impact of jemalloc memory profiler on execution time of multithreaded applications [№2 за 2015 год]
Authors: Ivanov E.Yu., Toropov A.V., Kosyakov M.S.
Visitors: 8022
This paper examines the performance impact of jemalloc memory profiler on execution time of multithreaded applications. Using popular synthetic tests the authors implemented a multithreaded application which allows varying different parameters related to memory allocation. A special criteria is suggested to com-pare and estimate profiling results. Tbricks algorithmic trading system is used to demonstrate that popular syn-thetic tests are not adequate enough to analyze memory profiling impact on operational characteristics of the ap-plication. Studies have shown that inactive profiling doesn’t affect the characteristics while with active profiling its values depend on sampling interval and can decrease manyfo ld. According to our analyses of jemalloc library source code related to memory profiling, the part which takes stacktraces is the main reason of extra overhead during profiling. Thus, we compare performance impact on operational characteristics of the app lication using libunwind and prof-libgcc stacktrace libraries: results of experiments made with libunwind stacktrace library are in average 20 % worse than with prof-libgcc. Based on experimental study we recommend using sampling inte r-val which allows of capturing information of at least 90 % of all allocated memory, while execution time of highly multithreaded applications decreases by less than 5 % in comparison with the disabled profiling. This al-lows analyzing memory allocations of applications while executing in production environment.

8. Investigation of the load prediction methods in computer and computer systems [№2 за 2015 год]
Authors: Brazhnikova Yu.S., Goritsky Yu.A., Kutepov V.P., Pankov N.A.
Visitors: 7329
The problem of process and resource management in large scale computer systems with thousands of components is important and has not been solved yet. Thus, a user has to determine the amount of resources needed for a computer system in advance and distribute parallel program fragments to achieve a desired acceleration effect and minimize resource usage. However, even for simple paralleling logic problems such a static planning strategy results in average resource utilization is no more than 15–20 %. The paper is devoted to the problem of computing system load level forecasting to create adaptive methods and algorithms for resource dynamic management and optimization algorithms. The paper presents the data of an experimental investigation of predicting workload of processors. It is based on various filtration methods of high-frequency signal which is processes assessable workload. The results show that among well known filters the median filters are the most precise. The results are used for the development of adaptive algorithms intended for resources optimization, in particular, for allocation of processor resources in computers and large computer systems.

9. The limitation method for verifiable models [№2 за 2015 год]
Authors: Korablin Yu.P., Shipov A.A.
Visitors: 9998
Nowadays software systems become more and more complex and sophisticated, so we need to have some use-ful instruments to check if they fit target specifications, especially if we are talking about large and distributed software sys-tems. The article demonstrates a new method which is the separate stage of verification process of information systems. It is intended to make verification more effective. Since the method is a separate verification step for Model Checking method and can be automated easily, its implementation to an existing technology is not a difficult task. The method is based on the principle saying that the model of all systems contains redundant computational sequences. They are not necessary to be analyzed during the properties verification process and it does not affect the final result. The main goal of this method is to exclude these computational sequences from the original model before certain properties veri-fication. The article provides a detailed description of the proposed method and its efficiency estimation. The theoretical material of the article includes illustrative examples of the method, in particular for distributed software system. The authors believe that using of this method can significantly reduce the number of analyzed sequences in verification process for a given system computational model, and thereby improve the performance of the process.

10. Modeling surface disturbance from the object moving in fluids [№2 за 2015 год]
Authors: Barulin А.V., Kulakov I.S.
Visitors: 6094
The problem of calculating environmental disturbance caused by object motion can be stated in many practical cases and dif-ferent objectives that can be: assessment of bogy characteristics and body flow when designing an object, calculation of obj ect motion pa-rameters (natural experiment is frequently changed by numerical simulation), research of flows and dam breaks, creating technologies of flu-id material processing. This problem can also be solved as one of 3D image synthesis stages of object motion in outside envir onment. When considering objects moving across water surface, we can face the problem of creating a dynamic image of interface disturbance (water and air). Talking about real-time image synthesis, an acceptable solution should be made in limited time. The results of this research were r e-ceived after searching synthesis methods of realistic 3D video reflection of object dynamic motion. However, the methodology as a base can possess communality. The paper considers an object moving with not high speed (about several meters per second) in fluid in a surface layer with some (any and in general changeable) deepening. It is required to calculate liquid surface disturbance, which caused by object motion.

| 1 | 2 | 3 | Next → ►