7,392 research outputs found
Adaptive feedback analysis and control of programmable stimuli for assessment of cerebrovascular function
The assessment of cerebrovascular regulatory mechanisms often requires flexibly controlled and precisely timed changes in arterial blood pressure (ABP) and/or inspired CO2. In this study, a new system for inducing variations in mean ABP was designed, implemented and tested using programmable sequences and programmable controls to induce pressure changes through bilateral thigh cuffs. The system is also integrated with a computer-controlled switch to select air or a CO2/air mixture to be provided via a face mask. Adaptive feedback control of a pressure generator was required to meet stringent specifications for fast changes, and accuracy in timing and pressure levels applied by the thigh cuffs. The implemented system consists of a PC-based signal analysis/control unit, a pressure control unit and a CO2/air control unit. Initial evaluations were carried out to compare the cuff pressure control performances between adaptive and non-adaptive control configurations. Results show that the adaptive control method can reduce the mean error in sustaining target pressure by 99.57 % and reduce the transient time in pressure increases by 45.21 %. The system has proven a highly effective tool in ongoing research on brain blood flow control
Hybrid System of Distributed Automation
One of the most important tendencies in the development of the
industrial automation is the application of intelligent control systems
within factories, which focuses heavily on networked architectures.
Following this line of thinking, the goal of this dissertation resumes itself
in the implementation of a distributed system that controls two physical
processes, where the system components not only trade information
between each other, but also have that same information be accessible
remotely and within HMI equipment.
The controllers were conceptualized to offer different functional modes
with high customization available.
This system also takes resource of an OPC server, so it allows, not only
the communication between different manufacturer PLC controllers but
also the connection with remotes clients
The implemented remote clients hold the intent of demonstrating the
versatility of this architecture and are, namely, an operational historian
that registers information and a data viewer, which allows the use of more
advanced methods of monitoring
System configuration and executive requirements specifications for reusable shuttle and space station/base
System configuration and executive requirements specifications for reusable shuttle and space station/bas
A NASA family of minicomputer systems, Appendix A
This investigation was undertaken to establish sufficient specifications, or standards, for minicomputer hardware and software to provide NASA with realizable economics in quantity purchases, interchangeability of minicomputers, software, storage and peripherals, and a uniformly high quality. The standards will define minicomputer system component types, each specialized to its intended NASA application, in as many levels of capacity as required
Space power distribution system technology. Volume 2: Autonomous power management
Electrical power subsystem requirements, power management system functional requirements, algorithms, power management subsystem, hardware development, and trade studies and analyses are discussed
Programmable electronic mining systems: best practice recommendations (in nine parts) : part 2, 2.1 System safety
"This report (An Introduction to Safety) is the first in a nine-part series of recommendations addressing the functional safety of processor-controlled mining equipment. It is part of a risk-based system safety process encompassing hardware, software, humans and the operating environment for the equipment's life cycle. The reports in this series address the various life cycle stages of inception, design, approval and certification, commissioning, operation, maintenance, and decommissioning. These recommendations were developed as a joint project between the National Institute for Occupational Safety and Health and the Mine Safety and Health Administration. They are intended for use by mining companies, original equipment manufacturers, and aftermarket suppliers to these mining companies. Users of these reports are expected to consider the set in total during the design cycle. 1.0 Safety Introduction - This is an introductory report for the general mining industry. It provides basic system/software safety concepts, discusses the need for mining to address the functional safety of programmable electronics, and includes the benefits of implementing a system/software safety program. 2.1 System Safety and 2.2 Software Safety - These reports draw heavily from International Electrotechnical Commission (IEC) standard 61508 and other recognized standards. The scope is "surface and underground safety mining systems employing embedded, networked, and non-networked programmable electronics." System safety seeks to design safety into all phases of the entire system. Software is a subsystem; thus, software safety is a part of the systems safety. 3.0 Safety File - This report contains the documentation that demonstrates the level of safety built into the system and identifies limitations for the system's use and operation. In essence, it is a "proof of safety" that the system and its operation meets the appropriate level of safety for the intended application. It starts from the beginning of the design, is maintained during the full life cycle of the system, and provides administrative support for the safety program of the full system. 4.0 Safety Assessment - The independent assessment of the Safety file is addressed. It establishes consistent methods to determine the completeness and suitability of safety evidence and justification. This assessment could be done by an independent third party. 5.0 Safety Framework Guidance - It is intended to supplement the safety framework reports with guidance that provides users with additional information. The purpose is to help users in applying the concepts presented. In other words, the safety framework is what needs to be done and the guidance is how it can be done. The guidance information reinforces the concepts, describes various methodologies that can be used and gives examples and references. It also gives information on the benefits and drawbacks of various methodologies. The guidance reports are not intended to promote a single methodology or to be an exhaustive treaty of the subject material. They provide information and references so that the user can more intelligently choose and implement the appropriate methodologies given the user's application and capabilities." - NIOSHTIC-
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