In order to measure the effectiveness of safety protection systems there are several design parameters. Diagnostic coverage factor is one of the most important parameter which influences all architectures. In this sho...
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In order to use electronic systems comprising of software and hardware components in safety related and high safety related applications, it is necessary to meet the Marginal risk numbers required by standards and leg...
In order to use electronic systems comprising of software and hardware components in safety related and high safety related applications, it is necessary to meet the Marginal risk numbers required by standards and legislative provisions. Existing processes and mathematical models are used to verify the risk numbers. On the hardware side, various accepted mathematical models, processes, and methods exist to provide the required proof. To this day, however, there are no closed models or mathematical procedures known that allow for a dependable prediction of software reliability. This work presents a method that makes a prognosis on the residual critical error number in software. Conventional models lack this ability and right now, there are no methods that forecast critical errors. The new method will show that an estimate of the residual error number of critical errors in software systems is possible by using a combination of prediction models, a ratio of critical errors, and the total error number. Subsequently, the critical expected value-function at any point in time can be derived from the new solution method, provided the detection rate has been calculated using an appropriate estimation method. Also, the presented method makes it possible to make an estimate on the critical failure rate. The approach is modelled on a real process and therefore describes two essential processes - detection and correction process.
Due to the complexity of microprocessor, an efficient testing is a crucial point and serious challenge in safety systems. A new instruction opcode for ALU based Built-In-Test (BIT) is proposed in this paper. With this...
Due to the complexity of microprocessor, an efficient testing is a crucial point and serious challenge in safety systems. A new instruction opcode for ALU based Built-In-Test (BIT) is proposed in this paper. With this novel method stuck-at-fault in Multiplexer (MUX) for Arithmetic Logic Unit (ALU) can be determined. A model that consists of the command and faulty states is developed. According to the designed state model, an algorithm and pseudo program that tests the stuck-at-fault in MUX is implemented and described in this paper.
This paper is concerned with the design procedures of an automated testing tool, developed in Matlab®/Simulink® environment, that performs software verification during runtime on a PLC (Programmable Logic Co...
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This paper describes a stereo-imaging system for variable distances. The setup includes a mechanical mount system-holder, a control unit for the correct positioning of the cameras, the cameras itself and the object to...
This paper describes a stereo-imaging system for variable distances. The setup includes a mechanical mount system-holder, a control unit for the correct positioning of the cameras, the cameras itself and the object to capture. The goal of this setup was to achieve a true sense of scale and depth of the filmed material on dynamically variable distances to the object. This demands certain requirements which are usually not necessary for many applications of stereoscopic filming. In the last step, the resulting material is prepared for viewing.
In order to measure the effectiveness of safety protection systems there are several design parameters. Diagnostic coverage factor is one of the most important parameter which influences all architectures. In this sho...
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In order to measure the effectiveness of safety protection systems there are several design parameters. Diagnostic coverage factor is one of the most important parameter which influences all architectures. In this short paper the relationship between PFD avg , DC and T I are presented. 1oo2 and 1oo2D architectures are considered as examples.
The paper is concerned with data transmission via channels composed of a memoryless binary symmetric channel and the erasure channel of Peter Elias. Channels of this type play an important role in modelling different ...
The paper is concerned with data transmission via channels composed of a memoryless binary symmetric channel and the erasure channel of Peter Elias. Channels of this type play an important role in modelling different types of networks especially wireless networks, and have been investigated using, amongst others, the theory of Markov chains. Channel Capacities and network flows have been determined. The authors focus their interest on some aspects of coding theory. They assume the data transmission to be protected by a linear code, a CRC for example, and determine the probability of undetected error of the code. They then consider redundant transmission via two or more channels with bit inversion, and calculate the probability of undetected error. They prove some inequalities that are useful instruments to estimate the rate of transmission errors and to determine safety integrity levels according to the standards. Finally the authors apply their results to Bluetooth channels suffering from different types of noise.
This paper is concerned with the design procedures of an automated testing tool, developed in Matlab ® /Simulink ® environment, that performs software verification during runtime on a PLC (Programmable Logi...
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This paper is concerned with the design procedures of an automated testing tool, developed in Matlab ® /Simulink ® environment, that performs software verification during runtime on a PLC (Programmable Logic Controller) or so called HiL test (Hardware-in-the-Loop) for model-based development of control applications. In addition to checking the “semantic” or “functional” correctness of the automatically generated C++ - Code with RTW (Real Time Workshop ® ) for algorithms designed and developed in Simulink ® on hardware targets, the tool compares results obtained from the HiL test with the results of the MiL test (Model-in-the-Loop) performed in early stage of development for the same developed application. The main purpose behind this work is to develop reliable software that fulfil system requirements and to test its behaviour during realtime hardware simulation, in order to achieve the validation step which represents the terminating - step of almost all projects.
Data flow processing is a common task of embedded systems which is usually modeled as a pipeline. Errors in a block of this pipeline can be propagated through it thus leading to unexpected and erroneous behaviors. For...
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Data flow processing is a common task of embedded systems which is usually modeled as a pipeline. Errors in a block of this pipeline can be propagated through it thus leading to unexpected and erroneous behaviors. For safety related applications, this pipeline has to be able to identify and react to failures. The DMOSES model-driven development method uses deterministic UML activities to describe and implement data flow processing. This method ensures deterministic behavior of concurrent processing. Design by Contract defines formal, precise and verifiable interfaces for software components. We propose a development method for safe data flow processing based on the integration of this concept in deterministic UML activities. This integration allows the identification of errors by detection of contracts violation. This paper presents an extension of the DMOSES tool for contracts verification at the model level and their monitoring at runtime.
The standard IEC/EN 61508 defines the requirements for safety systems to be applied to industrial plant safety independently of the application. It is not only intended as a basis for the development of future applica...
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ISBN:
(纸本)9784883254194
The standard IEC/EN 61508 defines the requirements for safety systems to be applied to industrial plant safety independently of the application. It is not only intended as a basis for the development of future application orientated standards, but also as a basis of all safety related electrical, electronic and programmable electronic systems, in order to apply it to safety critical applications. The purpose of this paper is to describe the SILCas tool which enables the user to determine the Safety Integrity Level (SIL) and the probability of failure on demand (PFD) for entire SIFs (consisting of sensor, signal processing, actuator) and for different systemarchitectures.
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