Methods of conversion of parametrical models of components modules at the design of Radio technical systems

Аuthors

Kuznetsov A. S.^1*, Kuznetsov S. N.^2**, Postnikova V. N.^2***

1. The State Pushkin Museum, 12/2, Prechistenka str., Moscow, 119034, Russia
2. Moscow Aviation Institute (National Research University), 4, Volokolamskoe shosse, Moscow, А-80, GSP-3, 125993, Russia

*e-mail: askuznetsov.gmp@gmail.com
**e-mail: serghei-k@mail.ru
***e-mail: apostnikov@mtu-net.ru

Abstract

The system approach in the course of the development of radio technical systems allows significantly reduce the development time and cost by using the modules of different production readiness [1].

The basis of information support of such of design systems is a database (DB), which is used for storage and selection of both parametrical models of the RTS modules, and parametrical models of the whole projects of Radio-Technical systems (RTS). Thus, a need emerges to carry out conversion of parametrical models of modules and their characteristics from the module storage format into the project storage format.

The execution time of procedure of modules converting in many respects depends both on DB’s creating, and on algorithms of performance of the separate functions, included in the procedure. To reduce the time of the converting procedure and thereby improve performance of the whole CAD is possible by using of the capabilities of modern databases.

Particularly, it is possible to use one of the two methods of creating of D. B.— by using cursor or temporary tables.

In the first case cursor, which represents the area in random access memory of the D. B. server to which all selected component modules are successively stored. In the second case, the parameters of the selected modules are stored in the temporary table. The conversion procedure is reduced to assigning to each module a unique composite key that corresponds to the format of the current project. For a large number of convertible modules the second case is preferable since using the cursor process of converting is carried out sequentially (line by line). That increases the time of conversion.

The most resource-intensive part of the process of conversion is a function of performing a hierarchical query. For creation a hierarchical query, it is possible to use such method as «parent/child» or method, which uses the type of data of HierarchyID [4, 5]. The main advantage of the HierarchyID method in comparison with the method of Parent/Child, is the ability eliminate the cycles and recursive queries CTE, which implementation consumes a lot of time. Particularly, when the number of modules (N) equals 10000, the time of query execution with the HierarchyID method, will be 15 times less, than in the first case. Therefore, this method is useful for a large number of modules, included in the hierarchical tree.

Thus, based on our research, we can conclude that the implementation of the conversion procedure for large Ns (N > 1000), to improve the performance of date support CAD it is reasonable to use DB with temporary tables, and while executing hierarchical query — a method, that uses the data type HierarchyID.

At the same time, with a small number of modules (N < 1000), both during convertsion procedure realization, and executing hierarchical queries, D. B.’s performance does not significantly depend on its structure. In this case, it makes sense to implement D. B. with simpler structure realization, such as, with the cursor using, and to execution of hierarchical requests — the Parent/Child method.

Keywords:

Computer-aided design, CAD, Databases, Hierarchical queries, Converting module components, Query optimization, Radio technical systems

References

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