Fault-Tolerant Air Data Inertial Reference System development results

2002 ◽  
Author(s):  
C.R. McClary ◽  
J.R. Walborn
Keyword(s):  
Reference System ◽  
Fault Tolerant ◽  
System Development

DEVELOPMENT OF COMPUTER SYSTEM COMPONENTS IN CRITICAL APPLICATIONS: PROBLEMS, THEIR ORIGINS AND SOLUTIONS

2020 ◽  
Vol 3 (4) ◽  
pp. 252-262
Author(s):  
Andrzej Rucinski ◽  
Igor S. Kovalev ◽  
Myroslav O. Drozd ◽  
Oleksandr V. Drozd ◽  
Viktor V. Antoniuk ◽  
...  
Keyword(s):  
Computer System ◽  
Fault Tolerant ◽  
System Development ◽  
Natural World ◽  
Point Of View ◽  
Functional Safety ◽  
Modern Computer ◽  
Software Model ◽  
Strongly Connected ◽  
Low Efficiency

The article is devoted to analysis of problems of the computer system development in the domain of critical applications. The main trends of this development were highlighted, which consisted in increased demands for performance based on parallelization of calculations, processing of approximate data and ensuring functional safety in accordance with the need for structuring for parallelism and fuzziness of the natural world, as well as with increased responsibility in decisions made. Analysis of problems encountered in implementation of existing solutions was carried out. There was a lag behind theories limited by the model of exact data from the practice of processing approximate data for modern systems receiving initial data from sensors, including safety-related systems. The problems of matrix structures, which underlie the design of modern computer systems and demonstrate low efficiency in performance and power consumption, as well as in providing functional safety, important for critical applications, are disclosed. The application of fault-tolerant solutions as the basis of functional safety and distrust of these solutions, which is manifested in the practice of using dangerous imitation modes, were noted. They recreate emergency conditions to improve the checkability in solving the problem of hidden faults, since a fault-tolerant solution does not become fail-safe when there is a shortage of checkability. An analysis was given to the sources of the problems considered and the possibilities of solving them from the point of view of a resource-based approach, which identifies the problem of hidden faults as a challenge of growth with a lag of components from the development of the system. The role of matrix structures in the backlog of components and the need to solve the problem by repeating the version redundancy for these structures are shown. Method of introduction of version redundancy into matrix structure on the basis of strongly connected versions for solution of problems of fault tolerance and checkability in complex is proposed. The effectiveness of the method is estimated on an example of the iterative array multiplier using its software model.

OPTIMAL COMPONENT SELECTION OF COTS BASED SOFTWARE SYSTEM UNDER CONSENSUS RECOVERY BLOCK SCHEME INCORPORATING EXECUTION TIME

2010 ◽  
Vol 17 (03) ◽  
pp. 209-222 ◽  
Author(s):  
P. C. JHA ◽  
P. K. KAPUR ◽  
SHIVANI BALI ◽  
U. DINESH KUMAR
Keyword(s):  
Execution Time ◽  
Fault Tolerant ◽  
System Development ◽  
Software Systems ◽  
Software System ◽  
Reliability Models ◽  
Development Costs ◽  
Software Modules ◽  
Reduce Development Time ◽  
Commercial Off The Shelf

Computer based systems have increased dramatically in scope, complexity, pervasiveness. Most industries are highly dependent on computers for their basic day to day functioning. Safe & reliable software operations are an essential requirement for many systems across different industries. The number of functions to be included in a software system is decided during the software development. Any software system must be constructed in such a way that execution can resume even after the occurrence of failure with minimal loss of data and time. Such software systems which can continue execution even in presence of faults are called fault tolerant software. When failure occurs one of the redundant software modules get executed and prevent system failure. The fault tolerant software systems are usually developed by integrating COTS (commercial off-the-shelf) software components. The motivation for using COTS components is that they will reduce overall system development costs and reduce development time. In this paper, reliability models for fault tolerant consensus recovery blocks are analyzed. In first optimization model, we formulate joint optimization problem in which reliability maximization of software system and execution time minimization for each function of software system are considered under budgetary constraint. In the second model the issue of compatibility among alternatives available for different modules, is discussed. Numerical illustrations are provided to demonstrate the developed models.

Control Development Process of the Brake-by-Wire System

2006 ◽  
Author(s):  
Francesco Canuto ◽  
Patrizio Turco ◽  
Davide Colombo
Keyword(s):  
Communication Network ◽  
Real Time ◽  
Fault Tolerant ◽  
Fault Injection ◽  
System Development ◽  
System Response ◽  
System Control ◽  
Environmental Aspect ◽  
Requirements Specifications ◽  
Wire System

The main goal of brake by wire technology is the development of compact, cheap and flexible braking systems. Since neither brake fluid nor hydraulic lines are used, brake by wire electro-mechanical actuation is a favourable solution both for production process and environmental aspect, and offer a precise control of braking torque amplitude. One of the most critical aspect is the lack of traditional link between brake pedal and brakes (calliper); this mean a potential safety problem to be correctly managed through the system architecture, redundancies, diagnosis and recoveries. During CRF brake by wire system development several architectures were deeply analysed using PHA, FMEA, and FTA methodology to identify the best configuration for production intent. The selected one is a fault-tolerant architecture based on a time-triggered communication network connecting fail-silent nodes. From safety analysis were defined critical events and system diagnosis and recovery requirements specifications. This paper describes the steps followed in the brake by wire software development, and its validation with respect to safety needs. For this purpose a three levels design and validation process was exploited. First of all, it was defined the complete simulation template including calliper electro-mechanical actuators and theirs ECU, time-triggered communication network and vehicle control ECU. The brake by wire system was interfaced to a complete vehicle dynamics model specifically developed for control design and validation purpose. Within this environment the control software was developed and the strategies were verified applying Software In the Loop technique. Then the ECU software was automatically generated using a customised tool chain based on Real Time Workshop Embedded Coder. Than, Hardware In the Loop testing was adopted to deeply verified high level software (application), low level software (OS, API, drivers,...) and hardware. HIL bench include the complete brake by wire system and a real time platform running the same vehicle model used during previous phase. Finally, vehicle testing phases complete the evaluation in the real environment and allows the system control development and tuning toward performances and subjective aspects. In each phase the system is tested both in normal and faulty conditions; a fault injection campaign was carried on to verify system response to fault with respect to the expected one. The process is cyclical, and a new loop has to be activated for each changes in the system. At the same time, testing complexity increases in order to guarantee the system safety.

scholarly journals INTRODUCTION OF THE INFORMATION AND REFERENCE SYSTEM "UNIBELL" IN THE EDUCATIONAL ENVIRONMENT INSTITUTION OF HIGHER EDUCATION

2020 ◽  
Vol 2 (1) ◽  
pp. 57-65
Author(s):  
O. V. Prydatko ◽  
◽  
N. Ye. Burak ◽  
V. Ye. Dzen ◽  
M. S. Kunynets ◽  
...  
Keyword(s):  
Set Theory ◽  
Reference System ◽  
System Development ◽  
Real Life ◽  
Scientific Work ◽  
Educational Environment ◽  
Educational Process ◽  
Remote Access ◽  
Training Schedule ◽  
Internal Stakeholders

Scientific work is aimed to identifying problem areas during distance educational process and to development of services that could help of solving them. Empirical methods and methods of real-life observation were used to collect the initial data for study. Processing of the obtained data is performed on the basis of using analytical methods and methods of expert evaluations. This allowed to identify weaknesses at distance education organization and to form a list of necessary services, which development and implementation will improve the quality of distance and inpatient educational process and education situation generally. The study identified and characterized the range of internal stakeholders of the educational environment, to meet the needs of which the development of these services is aimed. The results of empirical observations are presented using of set theory. To identify priority of declared services on the range for immediate implementation were provided their detailed analysis that showed high needs of an informational reference system development for remote access to the schedule with its further integration into educational environment. The proposed system is called "UniBell". This system is the part of education project "Smart-University", the main purpose of which is to integrate Universities into modern digital environment. Also, study defined the term "Smart University" or "Smart Educational Environment" and described main functionalities, general architecture and features of separate client as well as server parts of the "UniBell" service. Furthermore, features of additional subsystems of server part management, implemented with the use of software technologies.Net, Java and the language of structured queries SQL were highlighted. The model of client-server architecture, as well as algorithms for accounting and control of the training schedule have formed the basis for the development of an existing application for the Android operating system with the ability to download it via Google Play. The analysis of educational process virtualization has identified the main factors that may affect the educational process quality in the format of distance learning. The results of the analysis have become the basis for developing the architecture and algorithm of information system "UniBell" tasked to organize remote access to the training schedule using mobile technology. Using the conceptual apparatus of set theory, the volumes of internal stakeholders are investigated have been characterized, which provides a solid basis and target audience for further research on the effectiveness of the developed system in the Lviv State University of Life Safety educational environment.

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