Safety computer

The safety computer DIGISAFE XME is an evolution of the DIGISAFE platform used for railway automation applieations sinee 1989 first on SAGEM systems [GEO 90 MAR 90 HEN 94], see, for example, the RER A of the Parisian 

DIGISAFE is a registered trademark of Siemens Transportation Systems. 

The DIGISAFE computer is a calculation platform that we use for CBTC (communication based train control [lEE 04]) applications, whether for embedded computers or fixed computers. 

To fulfill this role, DIGISAFE secures all processing from input reading to output application, taking into account all layers of software architecture. 

Applications processed on this platform are cychcal during each cycle, the inputs are read, the calculations are made, taking into account these inputs and, of course, the internal states of the computer (variables), and determining the outputs. Finally, the outputs are applied. The inputs and outputs can be of several kinds  

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Research and development sponsorship has produced and accumulated, particularly within the Military Departments, a vast amount of new technology. This technology has served the defense establishment well in its mission to develop and acquire the weapons systems and materiel necessary for the defense of the nation. Large defense and aerospace contractors have transferred aircraft, air control and safety, computer and similar technology from the military sector to the civilian sector. 

The master copy of the Safety Computer punched paper tape will be stored in Document Control. 

Safety Computer Unintenuptibie Power Supply Supplementary Safety System (Seismic/Explosive Valve)... 

Cross Sections for Criticality Safety Computations,/f. K. Clark (DuPont-SRL)... 

Advances in cross-section processing have made criticality safety computations increasingly complex. The criticality safety analyst must select a suitable processing scheme and describe it well. 

In the early days of criticality safety computations, when a two-group diffusion theory calculation in cylindrical or spherical coordinates 1 desk calculator was a tedious and somewhat formidable task and when cross-section data were more sparse, the selection of cross sections was perhaps a sinqiler task. The fbur-fitctor formula was widely used for moderated systems. A factor was used to indicate the deviation from 1/v behavior of an absorption cross section at thermal energy. - Thermal and epithermal cross sections were related to the Integral parameters, diffusion area, and neutron age. 

The goal of any quality assurance program in criticality safety is to ensure that limits have been accurately established and will contribute to a safe operation. Computers are relied on to a great extent in most criticality safety programs and consequently are a key element in quality assurance programs in criticality safety. Computers are used at the Lawrence Livermore Laboratory (LLL) not only directly in criticality safety analysis but also in management of numerical and bibliographic criticality data that are needed for the validation of computational methods. 

An ability to communicate with scientists in both ADME, drug safety, computational chemistry, discovery chemistry, discovery biology, biostatistics, and information technology groups. 

In this chapter, we describe the architectural evolution of safety computers in the railway signaling sector, namely at Ansaldo STS. CSEE-Transport, a compaity estabhshed in 1902 to work the underground railway signals in Paris, became Ansaldo STS in July 2007. However, CSEE-Transport is better known as a world leader in high-speed signaling. 

This transmission is achieved through the rails. The train has sensors on the front of the first axle, which enables it to capture information from the ground. On board, the safety computer calculates and then displays the speed limit to the conductor, using the emergency break if the conductor does not respect the authorized Umit. 

For ground equipment TVM 430, and to meet the above constraints, the coded uniprocessor technology was modified and the ground safety computer TVM 430 divided into four blocks supported by four electronic cards. 

Under the Mediterranean LGV project, preliminaiy studies have shown the benefits of integrating interlocking and signaling functions into a single safety computer in order to significantly rednce the nnmber of safety relays necessary to set up a signaling terminal. 

The principle of the safety computer (outside availability) of the Mediterranean LGV is composed of five blocks supported by standard microprocessor cards, fir fact, the only safety constraint weighing on CSD equipment is the implementation of two independent clocks the safety of the computer is entirely ensnred by the software. 

The CSD is therefore a safety computer (or PU processing nnit) that receives and sends out safety messages. It acts as safety server with the application (the cyclic safety software developed by the CSD nser), receiving and cychcally delivering SACEM-coded and dated messages. 

In principle, the CSD exchanges safety messages with other safety computers, which may be CSDs or other types of computers (the latter must know the characteristics of encoding exchanged messages). 

It was the first signaling safety computer made in Franee put in service at the SNCF in 1995 then at the RATP in 2005 (see [GAL 08] whieh presents an overview of the safety demonstration conducted as part of the eonmiissioning of the PMI fine 3 bis of the Parisian imdergroimd system). 

The second initiative related to improving the reliability of follow-up actiom After considerable discussion among the Working Group, it was decided to computerise action tracking and monitoring as an addition to a safety computer... 

Factors of safety, computational margins for metallic materials of 1.25 against yield, 1.5 against ultimate stress and a minimum fatigue factor of 4. 

Safety Computer MC-29, VSF Status Trees Conduct of Operations Notification Procedure (RDP 12.02) Introduction to New Technical Specifications (REVD) Simulator Training... 

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