Embedded High Performance Scalable Computing Systems

National Research Council Canada - National Science Library

Ngo, David

2003-01-01

The Embedded High Performance Scalable Computing Systems (EHPSCS) program is a cooperative agreement between Sanders, A Lockheed Martin Company and DARPA that ran for three years, from Apr 1995 - Apr 1998...

Multiple Embedded Processors for Fault-Tolerant Computing

Science.gov (United States)

Bolotin, Gary; Watson, Robert; Katanyoutanant, Sunant; Burke, Gary; Wang, Mandy

2005-01-01

A fault-tolerant computer architecture has been conceived in an effort to reduce vulnerability to single-event upsets (spurious bit flips caused by impingement of energetic ionizing particles or photons). As in some prior fault-tolerant architectures, the redundancy needed for fault tolerance is obtained by use of multiple processors in one computer. Unlike prior architectures, the multiple processors are embedded in a single field-programmable gate array (FPGA). What makes this new approach practical is the recent commercial availability of FPGAs that are capable of having multiple embedded processors. A working prototype (see figure) consists of two embedded IBM PowerPC 405 processor cores and a comparator built on a Xilinx Virtex-II Pro FPGA. This relatively simple instantiation of the architecture implements an error-detection scheme. A planned future version, incorporating four processors and two comparators, would correct some errors in addition to detecting them.

Embedding Moodle into Ubiquitous Computing Environments

NARCIS (Netherlands)

Glahn, Christian; Specht, Marcus

2010-01-01

Glahn, C., & Specht, M. (2010). Embedding Moodle into Ubiquitous Computing Environments. In M. Montebello, et al. (Eds.), 9th World Conference on Mobile and Contextual Learning (MLearn2010) (pp. 100-107). October, 19-22, 2010, Valletta, Malta.

Spacecraft computer technology at Southwest Research Institute

Science.gov (United States)

Shirley, D. J.

1993-01-01

Southwest Research Institute (SwRI) has developed and delivered spacecraft computers for a number of different near-Earth-orbit spacecraft including shuttle experiments and SDIO free-flyer experiments. We describe the evolution of the basic SwRI spacecraft computer design from those weighing in at 20 to 25 lb and using 20 to 30 W to newer models weighing less than 5 lb and using only about 5 W, yet delivering twice the processing throughput. Because of their reduced size, weight, and power, these newer designs are especially applicable to planetary instrument requirements. The basis of our design evolution has been the availability of more powerful processor chip sets and the development of higher density packaging technology, coupled with more aggressive design strategies in incorporating high-density FPGA technology and use of high-density memory chips. In addition to reductions in size, weight, and power, the newer designs also address the necessity of survival in the harsh radiation environment of space. Spurred by participation in such programs as MSTI, LACE, RME, Delta 181, Delta Star, and RADARSAT, our designs have evolved in response to program demands to be small, low-powered units, radiation tolerant enough to be suitable for both Earth-orbit microsats and for planetary instruments. Present designs already include MIL-STD-1750 and Multi-Chip Module (MCM) technology with near-term plans to include RISC processors and higher-density MCM's. Long term plans include development of whole-core processors on one or two MCM's.

Tools for Embedded Computing Systems Software

Science.gov (United States)

1978-01-01

A workshop was held to assess the state of tools for embedded systems software and to determine directions for tool development. A synopsis of the talk and the key figures of each workshop presentation, together with chairmen summaries, are presented. The presentations covered four major areas: (1) tools and the software environment (development and testing); (2) tools and software requirements, design, and specification; (3) tools and language processors; and (4) tools and verification and validation (analysis and testing). The utility and contribution of existing tools and research results for the development and testing of embedded computing systems software are described and assessed.

Computer vision camera with embedded FPGA processing

Science.gov (United States)

Lecerf, Antoine; Ouellet, Denis; Arias-Estrada, Miguel

2000-03-01

Traditional computer vision is based on a camera-computer system in which the image understanding algorithms are embedded in the computer. To circumvent the computational load of vision algorithms, low-level processing and imaging hardware can be integrated in a single compact module where a dedicated architecture is implemented. This paper presents a Computer Vision Camera based on an open architecture implemented in an FPGA. The system is targeted to real-time computer vision tasks where low level processing and feature extraction tasks can be implemented in the FPGA device. The camera integrates a CMOS image sensor, an FPGA device, two memory banks, and an embedded PC for communication and control tasks. The FPGA device is a medium size one equivalent to 25,000 logic gates. The device is connected to two high speed memory banks, an IS interface, and an imager interface. The camera can be accessed for architecture programming, data transfer, and control through an Ethernet link from a remote computer. A hardware architecture can be defined in a Hardware Description Language (like VHDL), simulated and synthesized into digital structures that can be programmed into the FPGA and tested on the camera. The architecture of a classical multi-scale edge detection algorithm based on a Laplacian of Gaussian convolution has been developed to show the capabilities of the system.

Disclosive Computer Ethics: The Exposure and Evaluation of Embedded Normativity in Computer Technology.

NARCIS (Netherlands)

Brey, Philip A.E.

2000-01-01

This essay provides a critique of mainstream computer ethics and argues for the importance of a complementary approach called disclosive computer ethics, which is concerned with the moral deciphering of embedded values and norms in computer systems, applications and practices. Also, four key values

A spacecraft computer repairable via command.

Science.gov (United States)

Fimmel, R. O.; Baker, T. E.

1971-01-01

The MULTIPAC is a central data system developed for deep-space probes with the distinctive feature that it may be repaired during flight via command and telemetry links by reprogramming around the failed unit. The computer organization uses pools of identical modules which the program organizes into one or more computers called processors. The interaction of these modules is dynamically controlled by the program rather than hardware. In the event of a failure, new programs are entered which reorganize the central data system with a somewhat reduced total processing capability aboard the spacecraft. Emphasis is placed on the evolution of the system architecture and the final overall system design rather than the specific logic design.

Integrating Embedded Computing Systems into High School and Early Undergraduate Education

Science.gov (United States)

Benson, B.; Arfaee, A.; Choon Kim; Kastner, R.; Gupta, R. K.

2011-01-01

Early exposure to embedded computing systems is crucial for students to be prepared for the embedded computing demands of today's world. However, exposure to systems knowledge often comes too late in the curriculum to stimulate students' interests and to provide a meaningful difference in how they direct their choice of electives for future…

Rad-hard embedded computers for nuclear robotics

International Nuclear Information System (INIS)

Giraud, A.; Joffre, F.; Marceau, M.; Robiolle, M.; Brunet, J.P.; Mijuin, D.

1993-01-01

For requirements of nuclear industries, it is necessary to use robots with embedded rad hard electronics and high level safety. The computer developed for french research program SYROCO is presented in this paper. (authors). 8 refs., 5 figs

Dissertation Defense Computational Fluid Dynamics Uncertainty Analysis for Payload Fairing Spacecraft Environmental Control Systems

Science.gov (United States)

Groves, Curtis Edward

2014-01-01

Spacecraft thermal protection systems are at risk of being damaged due to airflow produced from Environmental Control Systems. There are inherent uncertainties and errors associated with using Computational Fluid Dynamics to predict the airflow field around a spacecraft from the Environmental Control System. This paper describes an approach to quantify the uncertainty in using Computational Fluid Dynamics to predict airflow speeds around an encapsulated spacecraft without the use of test data. Quantifying the uncertainty in analytical predictions is imperative to the success of any simulation-based product. The method could provide an alternative to traditional "validation by test only" mentality. This method could be extended to other disciplines and has potential to provide uncertainty for any numerical simulation, thus lowering the cost of performing these verifications while increasing the confidence in those predictions. Spacecraft requirements can include a maximum airflow speed to protect delicate instruments during ground processing. Computational Fluid Dynamics can be used to verify these requirements; however, the model must be validated by test data. This research includes the following three objectives and methods. Objective one is develop, model, and perform a Computational Fluid Dynamics analysis of three (3) generic, non-proprietary, environmental control systems and spacecraft configurations. Several commercially available and open source solvers have the capability to model the turbulent, highly three-dimensional, incompressible flow regime. The proposed method uses FLUENT, STARCCM+, and OPENFOAM. Objective two is to perform an uncertainty analysis of the Computational Fluid Dynamics model using the methodology found in "Comprehensive Approach to Verification and Validation of Computational Fluid Dynamics Simulations". This method requires three separate grids and solutions, which quantify the error bars around Computational Fluid Dynamics

Dissertation Defense: Computational Fluid Dynamics Uncertainty Analysis for Payload Fairing Spacecraft Environmental Control Systems

Science.gov (United States)

Groves, Curtis Edward

2014-01-01

Spacecraft thermal protection systems are at risk of being damaged due to airflow produced from Environmental Control Systems. There are inherent uncertainties and errors associated with using Computational Fluid Dynamics to predict the airflow field around a spacecraft from the Environmental Control System. This paper describes an approach to quantify the uncertainty in using Computational Fluid Dynamics to predict airflow speeds around an encapsulated spacecraft without the use of test data. Quantifying the uncertainty in analytical predictions is imperative to the success of any simulation-based product. The method could provide an alternative to traditional validation by test only mentality. This method could be extended to other disciplines and has potential to provide uncertainty for any numerical simulation, thus lowering the cost of performing these verifications while increasing the confidence in those predictions.Spacecraft requirements can include a maximum airflow speed to protect delicate instruments during ground processing. Computational Fluid Dynamics can be used to verify these requirements; however, the model must be validated by test data. This research includes the following three objectives and methods. Objective one is develop, model, and perform a Computational Fluid Dynamics analysis of three (3) generic, non-proprietary, environmental control systems and spacecraft configurations. Several commercially available and open source solvers have the capability to model the turbulent, highly three-dimensional, incompressible flow regime. The proposed method uses FLUENT, STARCCM+, and OPENFOAM. Objective two is to perform an uncertainty analysis of the Computational Fluid Dynamics model using the methodology found in Comprehensive Approach to Verification and Validation of Computational Fluid Dynamics Simulations. This method requires three separate grids and solutions, which quantify the error bars around Computational Fluid Dynamics predictions

Application of advanced electronics to a future spacecraft computer design

Science.gov (United States)

Carney, P. C.

1980-01-01

Advancements in hardware and software technology are summarized with specific emphasis on spacecraft computer capabilities. Available state of the art technology is reviewed and candidate architectures are defined.

The selection of embedded computer using in the nuclear physics instruments

International Nuclear Information System (INIS)

Zhang Jianchuan; Nan Gangyang; Wang Yanyu; Su Hong

2010-01-01

It introduces the requirement for embedded PC and the benefits of using it in the experimental nuclear physics instrument developing and improving project. A cording to the specific requirements in the project of improving laboratory instruments. several kinds of embedded computer are compared and specifically tested. Thus, a x86 architecture embedded computer, which have ultra-low-power consumption and a small in size, is selected to be the main component of the controller using in the nuclear physics instrument, and this will be used in the high-speed data acquisition and electronic control system. (authors)

Soft-error tolerance and energy consumption evaluation of embedded computer with magnetic random access memory in practical systems using computer simulations

Science.gov (United States)

Nebashi, Ryusuke; Sakimura, Noboru; Sugibayashi, Tadahiko

2017-08-01

We evaluated the soft-error tolerance and energy consumption of an embedded computer with magnetic random access memory (MRAM) using two computer simulators. One is a central processing unit (CPU) simulator of a typical embedded computer system. We simulated the radiation-induced single-event-upset (SEU) probability in a spin-transfer-torque MRAM cell and also the failure rate of a typical embedded computer due to its main memory SEU error. The other is a delay tolerant network (DTN) system simulator. It simulates the power dissipation of wireless sensor network nodes of the system using a revised CPU simulator and a network simulator. We demonstrated that the SEU effect on the embedded computer with 1 Gbit MRAM-based working memory is less than 1 failure in time (FIT). We also demonstrated that the energy consumption of the DTN sensor node with MRAM-based working memory can be reduced to 1/11. These results indicate that MRAM-based working memory enhances the disaster tolerance of embedded computers.

7th International Conference on Embedded and Multimedia Computing (EMC-12)

CERN Document Server

Jeong, Young-Sik; Park, Sang; Chen, Hsing-Chung; Embedded and Multimedia Computing Technology and Service

2012-01-01

The 7th International Conference on Embedded and Multimedia Computing (EMC-12), will be held in Gwangju, Korea on September 6 - 8, 2012. EMC-12 will be the most comprehensive conference focused on the various aspects of advances in Embedded and Multimedia (EM) Computing. EMC-12 will provide an opportunity for academic and industry professionals to discuss the latest issues and progress in the area of EM. In addition, the conference will publish high quality papers which are closely related to the various theories and practical applications in EM. Furthermore, we expect that the conference and its publications will be a trigger for further related research and technology improvements in this important subject. The EMC-12 is the next event, in a series of highly successful International Conference on Embedded and Multimedia Computing, previously held as EMC 2011 (China, Aug. 2011), EMC 2010 (Philippines, Aug. 2010), EM-Com 2009 (Korea, Dec. 2009), UMC-08 (Australia, Oct. 2008), ESO-08(China, Dec. 2008), UMS-08 ...

Computer Game Play as an Imaginary Stage for Reading: Implicit Spatial Effects of Computer Games Embedded in Hard Copy Books

Science.gov (United States)

Smith, Glenn Gordon

2012-01-01

This study compared books with embedded computer games (via pentop computers with microdot paper and audio feedback) with regular books with maps, in terms of fifth graders' comprehension and retention of spatial details from stories. One group read a story in hard copy with embedded computer games, the other group read it in regular book format…

A computer graphics system for visualizing spacecraft in orbit

Science.gov (United States)

Eyles, Don E.

1989-01-01

To carry out unanticipated operations with resources already in space is part of the rationale for a permanently manned space station in Earth orbit. The astronauts aboard a space station will require an on-board, spatial display tool to assist the planning and rehearsal of upcoming operations. Such a tool can also help astronauts to monitor and control such operations as they occur, especially in cases where first-hand visibility is not possible. A computer graphics visualization system designed for such an application and currently implemented as part of a ground-based simulation is described. The visualization system presents to the user the spatial information available in the spacecraft's computers by drawing a dynamic picture containing the planet Earth, the Sun, a star field, and up to two spacecraft. The point of view within the picture can be controlled by the user to obtain a number of specific visualization functions. The elements of the display, the methods used to control the display's point of view, and some of the ways in which the system can be used are described.

Embedded Systems

Indian Academy of Sciences (India)

Embedded system, micro-con- troller ... Embedded systems differ from general purpose computers in many ... Low cost: As embedded systems are extensively used in con- .... operating systems for the desktop computers where scheduling.

Embedded systems for supporting computer accessibility.

Science.gov (United States)

Mulfari, Davide; Celesti, Antonio; Fazio, Maria; Villari, Massimo; Puliafito, Antonio

2015-01-01

Nowadays, customized AT software solutions allow their users to interact with various kinds of computer systems. Such tools are generally available on personal devices (e.g., smartphones, laptops and so on) commonly used by a person with a disability. In this paper, we investigate a way of using the aforementioned AT equipments in order to access many different devices without assistive preferences. The solution takes advantage of open source hardware and its core component consists of an affordable Linux embedded system: it grabs data coming from the assistive software, which runs on the user's personal device, then, after processing, it generates native keyboard and mouse HID commands for the target computing device controlled by the end user. This process supports any operating system available on the target machine and it requires no specialized software installation; therefore the user with a disability can rely on a single assistive tool to control a wide range of computing platforms, including conventional computers and many kinds of mobile devices, which receive input commands through the USB HID protocol.

A Trusted Computing Architecture of Embedded System Based on Improved TPM

Directory of Open Access Journals (Sweden)

Wang Xiaosheng

2017-01-01

Full Text Available The Trusted Platform Module (TPM currently used by PCs is not suitable for embedded systems, it is necessary to improve existing TPM. The paper proposes a trusted computing architecture with new TPM and the cryptographic system developed by China for the embedded system. The improved TPM consists of the Embedded System Trusted Cryptography Module (eTCM and the Embedded System Trusted Platform Control Module (eTPCM, which are combined and implemented the TPM’s autonomous control, active defense, high-speed encryption/decryption and other function through its internal bus arbitration module and symmetric and asymmetric cryptographic engines to effectively protect the security of embedded system. In our improved TPM, a trusted measurement method with chain model and star type model is used. Finally, the improved TPM is designed by FPGA, and it is used to a trusted PDA to carry out experimental verification. Experiments show that the trusted architecture of the embedded system based on the improved TPM is efficient, reliable and secure.

Application of software technology to a future spacecraft computer design

Science.gov (United States)

Labaugh, R. J.

1980-01-01

A study was conducted to determine how major improvements in spacecraft computer systems can be obtained from recent advances in hardware and software technology. Investigations into integrated circuit technology indicated that the CMOS/SOS chip set being developed for the Air Force Avionics Laboratory at Wright Patterson had the best potential for improving the performance of spaceborne computer systems. An integral part of the chip set is the bit slice arithmetic and logic unit. The flexibility allowed by microprogramming, combined with the software investigations, led to the specification of a baseline architecture and instruction set.

A computer graphics pilot project - Spacecraft mission support with an interactive graphics workstation

Science.gov (United States)

Hagedorn, John; Ehrner, Marie-Jacqueline; Reese, Jodi; Chang, Kan; Tseng, Irene

1986-01-01

The NASA Computer Graphics Pilot Project was undertaken to enhance the quality control, productivity and efficiency of mission support operations at the Goddard Operations Support Computing Facility. The Project evolved into a set of demonstration programs for graphics intensive simulated control room operations, particularly in connection with the complex space missions that began in the 1980s. Complex mission mean more data. Graphic displays are a means to reduce the probabilities of operator errors. Workstations were selected with 1024 x 768 pixel color displays controlled by a custom VLSI chip coupled to an MC68010 chip running UNIX within a shell that permits operations through the medium of mouse-accessed pulldown window menus. The distributed workstations run off a host NAS 8040 computer. Applications of the system for tracking spacecraft orbits and monitoring Shuttle payload handling illustrate the system capabilities, noting the built-in capabilities of shifting the point of view and rotating and zooming in on three-dimensional views of spacecraft.

Embedded Volttron specification - benchmarking small footprint compute device for Volttron

Energy Technology Data Exchange (ETDEWEB)

Sanyal, Jibonananda [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Fugate, David L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Woodworth, Ken [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Nutaro, James J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kuruganti, Teja [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2015-08-17

An embedded system is a small footprint computing unit that typically serves a specific purpose closely associated with measurements and control of hardware devices. These units are designed for reasonable durability and operations in a wide range of operating conditions. Some embedded systems support real-time operations and can demonstrate high levels of reliability. Many have failsafe mechanisms built to handle graceful shutdown of the device in exception conditions. The available memory, processing power, and network connectivity of these devices are limited due to the nature of their specific-purpose design and intended application. Industry practice is to carefully design the software for the available hardware capability to suit desired deployment needs. Volttron is an open source agent development and deployment platform designed to enable researchers to interact with devices and appliances without having to write drivers themselves. Hosting Volttron on small footprint embeddable devices enables its demonstration for embedded use. This report details the steps required and the experience in setting up and running Volttron applications on three small footprint devices: the Intel Next Unit of Computing (NUC), the Raspberry Pi 2, and the BeagleBone Black. In addition, the report also details preliminary investigation of the execution performance of Volttron on these devices.

An embedded single-board computer for BPM of SSRF

International Nuclear Information System (INIS)

Chen Kai; Liu Shubin; Yan Han; Wu Weihao; Zhao Lei; An Qi; Leng Yongbin; Yi Xing; Yan Yingbing; Lai Longwei

2011-01-01

An embedded single-board computer (SBC) system based on AT91RM9200 was designed for monitoring and controlling the digital beam position monitor system of Shanghai Synchrotron Radiation Facility (SSRF) through the Virtex-4 FPGA in the digital processing board. The SBC transfers the configuration commands from the remote EPICS to the FPGA, and calculates the beam position data. The interface between the FPGA and the SBC is the Static Memory Controller (SMC) with a peak transfer speed of up to 349 Mbps. The 100 Mb Ethernet is used for data transfer between the EPICS and SBC board, and a serial port serves as monitoring the status of the embedded system. Test results indicate that the SBC board functions well. (authors)

A general method for computing the total solar radiation force on complex spacecraft structures

Science.gov (United States)

Chan, F. K.

1981-01-01

The method circumvents many of the existing difficulties in computational logic presently encountered in the direct analytical or numerical evaluation of the appropriate surface integral. It may be applied to complex spacecraft structures for computing the total force arising from either specular or diffuse reflection or even from non-Lambertian reflection and re-radiation.

A Middleware Platform for Providing Mobile and Embedded Computing Instruction to Software Engineering Students

Science.gov (United States)

Mattmann, C. A.; Medvidovic, N.; Malek, S.; Edwards, G.; Banerjee, S.

2012-01-01

As embedded software systems have grown in number, complexity, and importance in the modern world, a corresponding need to teach computer science students how to effectively engineer such systems has arisen. Embedded software systems, such as those that control cell phones, aircraft, and medical equipment, are subject to requirements and…

Using neuromorphic optical sensors for spacecraft absolute and relative navigation

Science.gov (United States)

Shake, Christopher M.

We develop a novel attitude determination system (ADS) for use on nano spacecraft using neuromorphic optical sensors. The ADS intends to support nano-satellite operations by providing low-cost, low-mass, low-volume, low-power, and redundant attitude determination capabilities with quick and straightforward onboard programmability for real time spacecraft operations. The ADS is experimentally validated with commercial-off-the-shelf optical devices that perform sensing and image processing on the same circuit board and are biologically inspired by insects' vision systems, which measure optical flow while navigating in the environment. The firmware on the devices is modified to both perform the additional biologically inspired task of tracking objects and communicate with a PC/104 form-factor embedded computer running Real Time Application Interface Linux used on a spacecraft simulator. Algorithms are developed for operations using optical flow, point tracking, and hybrid modes with the sensors, and the performance of the system in all three modes is assessed using a spacecraft simulator in the Advanced Autonomous Multiple Spacecraft (ADAMUS) laboratory at Rensselaer. An existing relative state determination method is identified to be combined with the novel ADS to create a self-contained navigation system for nano spacecraft. The performance of the method is assessed in simulation and found not to match the results from its authors using only conditions and equations already published. An improved target inertia tensor method is proposed as an update to the existing relative state method, but found not to perform as expected, but is presented for others to build upon.

Fault tolerant embedded computers and power electronics for nuclear robotics

International Nuclear Information System (INIS)

Giraud, A.; Robiolle, M.

1995-01-01

For requirements of nuclear industries, it is necessary to use embedded rad-tolerant electronics and high-level safety. In this paper, we first describe a computer architecture called MICADO designed for French nuclear industry. We then present outgoing projects on our industry. A special point is made on power electronics for remote-operated and legged robots. (authors). 7 refs., 2 figs

Fault tolerant embedded computers and power electronics for nuclear robotics

Energy Technology Data Exchange (ETDEWEB)

Giraud, A.; Robiolle, M.

1995-12-31

For requirements of nuclear industries, it is necessary to use embedded rad-tolerant electronics and high-level safety. In this paper, we first describe a computer architecture called MICADO designed for French nuclear industry. We then present outgoing projects on our industry. A special point is made on power electronics for remote-operated and legged robots. (authors). 7 refs., 2 figs.

Adaptive Management of Computing and Network Resources for Spacecraft Systems

Science.gov (United States)

Pfarr, Barbara; Welch, Lonnie R.; Detter, Ryan; Tjaden, Brett; Huh, Eui-Nam; Szczur, Martha R. (Technical Monitor)

2000-01-01

It is likely that NASA's future spacecraft systems will consist of distributed processes which will handle dynamically varying workloads in response to perceived scientific events, the spacecraft environment, spacecraft anomalies and user commands. Since all situations and possible uses of sensors cannot be anticipated during pre-deployment phases, an approach for dynamically adapting the allocation of distributed computational and communication resources is needed. To address this, we are evolving the DeSiDeRaTa adaptive resource management approach to enable reconfigurable ground and space information systems. The DeSiDeRaTa approach embodies a set of middleware mechanisms for adapting resource allocations, and a framework for reasoning about the real-time performance of distributed application systems. The framework and middleware will be extended to accommodate (1) the dynamic aspects of intra-constellation network topologies, and (2) the complete real-time path from the instrument to the user. We are developing a ground-based testbed that will enable NASA to perform early evaluation of adaptive resource management techniques without the expense of first deploying them in space. The benefits of the proposed effort are numerous, including the ability to use sensors in new ways not anticipated at design time; the production of information technology that ties the sensor web together; the accommodation of greater numbers of missions with fewer resources; and the opportunity to leverage the DeSiDeRaTa project's expertise, infrastructure and models for adaptive resource management for distributed real-time systems.

User interfaces for computational science: A domain specific language for OOMMF embedded in Python

Science.gov (United States)

Beg, Marijan; Pepper, Ryan A.; Fangohr, Hans

2017-05-01

Computer simulations are used widely across the engineering and science disciplines, including in the research and development of magnetic devices using computational micromagnetics. In this work, we identify and review different approaches to configuring simulation runs: (i) the re-compilation of source code, (ii) the use of configuration files, (iii) the graphical user interface, and (iv) embedding the simulation specification in an existing programming language to express the computational problem. We identify the advantages and disadvantages of different approaches and discuss their implications on effectiveness and reproducibility of computational studies and results. Following on from this, we design and describe a domain specific language for micromagnetics that is embedded in the Python language, and allows users to define the micromagnetic simulations they want to carry out in a flexible way. We have implemented this micromagnetic simulation description language together with a computational backend that executes the simulation task using the Object Oriented MicroMagnetic Framework (OOMMF). We illustrate the use of this Python interface for OOMMF by solving the micromagnetic standard problem 4. All the code is publicly available and is open source.

Computer-Automated Evolution of Spacecraft X-Band Antennas

Science.gov (United States)

Lohn, Jason D.; Homby, Gregory S.; Linden, Derek S.

2010-01-01

A document discusses the use of computer- aided evolution in arriving at a design for X-band communication antennas for NASA s three Space Technology 5 (ST5) satellites, which were launched on March 22, 2006. Two evolutionary algorithms, incorporating different representations of the antenna design and different fitness functions, were used to automatically design and optimize an X-band antenna design. A set of antenna designs satisfying initial ST5 mission requirements was evolved by use these algorithms. The two best antennas - one from each evolutionary algorithm - were built. During flight-qualification testing of these antennas, the mission requirements were changed. After minimal changes in the evolutionary algorithms - mostly in the fitness functions - new antenna designs satisfying the changed mission requirements were evolved and within one month of this change, two new antennas were designed and prototypes of the antennas were built and tested. One of these newly evolved antennas was approved for deployment on the ST5 mission, and flight-qualified versions of this design were built and installed on the spacecraft. At the time of writing the document, these antennas were the first computer-evolved hardware in outer space.

Embedded Processor Laboratory

Data.gov (United States)

Federal Laboratory Consortium — The Embedded Processor Laboratory provides the means to design, develop, fabricate, and test embedded computers for missile guidance electronics systems in support...

User interfaces for computational science: A domain specific language for OOMMF embedded in Python

Directory of Open Access Journals (Sweden)

Marijan Beg

2017-05-01

Full Text Available Computer simulations are used widely across the engineering and science disciplines, including in the research and development of magnetic devices using computational micromagnetics. In this work, we identify and review different approaches to configuring simulation runs: (i the re-compilation of source code, (ii the use of configuration files, (iii the graphical user interface, and (iv embedding the simulation specification in an existing programming language to express the computational problem. We identify the advantages and disadvantages of different approaches and discuss their implications on effectiveness and reproducibility of computational studies and results. Following on from this, we design and describe a domain specific language for micromagnetics that is embedded in the Python language, and allows users to define the micromagnetic simulations they want to carry out in a flexible way. We have implemented this micromagnetic simulation description language together with a computational backend that executes the simulation task using the Object Oriented MicroMagnetic Framework (OOMMF. We illustrate the use of this Python interface for OOMMF by solving the micromagnetic standard problem 4. All the code is publicly available and is open source.

Computational Model for Spacecraft/Habitat Volume

Data.gov (United States)

National Aeronautics and Space Administration — Please note that funding to Dr. Simon Hsiang, a critical co-investigator for the development of the Spacecraft Optimization Layout and Volume (SOLV) model, was...

Securing Embedded Smart Cameras with Trusted Computing

Directory of Open Access Journals (Sweden)

Winkler Thomas

2011-01-01

Full Text Available Camera systems are used in many applications including video surveillance for crime prevention and investigation, traffic monitoring on highways or building monitoring and automation. With the shift from analog towards digital systems, the capabilities of cameras are constantly increasing. Today's smart camera systems come with considerable computing power, large memory, and wired or wireless communication interfaces. With onboard image processing and analysis capabilities, cameras not only open new possibilities but also raise new challenges. Often overlooked are potential security issues of the camera system. The increasing amount of software running on the cameras turns them into attractive targets for attackers. Therefore, the protection of camera devices and delivered data is of critical importance. In this work we present an embedded camera prototype that uses Trusted Computing to provide security guarantees for streamed videos. With a hardware-based security solution, we ensure integrity, authenticity, and confidentiality of videos. Furthermore, we incorporate image timestamping, detection of platform reboots, and reporting of the system status. This work is not limited to theoretical considerations but also describes the implementation of a prototype system. Extensive evaluation results illustrate the practical feasibility of the approach.

Computing in the presence of soft bit errors. [caused by single event upset on spacecraft

Science.gov (United States)

Rasmussen, R. D.

1984-01-01

It is shown that single-event-upsets (SEUs) due to cosmic rays are a significant source of single bit error in spacecraft computers. The physical mechanism of SEU, electron hole generation by means of Linear Energy Transfer (LET), it discussed with reference made to the results of a study of the environmental effects on computer systems of the Galileo spacecraft. Techniques for making software more tolerant of cosmic ray effects are considered, including: reducing the number of registers used by the software; continuity testing of variables; redundant execution of major procedures for error detection; and encoding state variables to detect single-bit changes. Attention is also given to design modifications which may reduce the cosmic ray exposure of on-board hardware. These modifications include: shielding components operating in LEO; removing low-power Schottky parts; and the use of CMOS diodes. The SEU parameters of different electronic components are listed in a table.

Technology for organization of the onboard system for processing and storage of ERS data for ultrasmall spacecraft

Science.gov (United States)

Strotov, Valery V.; Taganov, Alexander I.; Konkin, Yuriy V.; Kolesenkov, Aleksandr N.

2017-10-01

Task of processing and analysis of obtained Earth remote sensing data on ultra-small spacecraft board is actual taking into consideration significant expenditures of energy for data transfer and low productivity of computers. Thereby, there is an issue of effective and reliable storage of the general information flow obtained from onboard systems of information collection, including Earth remote sensing data, into a specialized data base. The paper has considered peculiarities of database management system operation with the multilevel memory structure. For storage of data in data base the format has been developed that describes a data base physical structure which contains required parameters for information loading. Such structure allows reducing a memory size occupied by data base because it is not necessary to store values of keys separately. The paper has shown architecture of the relational database management system oriented into embedment into the onboard ultra-small spacecraft software. Data base for storage of different information, including Earth remote sensing data, can be developed by means of such database management system for its following processing. Suggested database management system architecture has low requirements to power of the computer systems and memory resources on the ultra-small spacecraft board. Data integrity is ensured under input and change of the structured information.

Embedded engineering education

CERN Document Server

Kaštelan, Ivan; Temerinac, Miodrag; Barak, Moshe; Sruk, Vlado

2016-01-01

This book focuses on the outcome of the European research project “FP7-ICT-2011-8 / 317882: Embedded Engineering Learning Platform” E2LP. Additionally, some experiences and researches outside this project have been included. This book provides information about the achieved results of the E2LP project as well as some broader views about the embedded engineering education. It captures project results and applications, methodologies, and evaluations. It leads to the history of computer architectures, brings a touch of the future in education tools and provides a valuable resource for anyone interested in embedded engineering education concepts, experiences and material. The book contents 12 original contributions and will open a broader discussion about the necessary knowledge and appropriate learning methods for the new profile of embedded engineers. As a result, the proposed Embedded Computer Engineering Learning Platform will help to educate a sufficient number of future engineers in Europe, capable of d...

Energy-aware memory management for embedded multimedia systems a computer-aided design approach

CERN Document Server

Balasa, Florin

2011-01-01

Energy-Aware Memory Management for Embedded Multimedia Systems: A Computer-Aided Design Approach presents recent computer-aided design (CAD) ideas that address memory management tasks, particularly the optimization of energy consumption in the memory subsystem. It explains how to efficiently implement CAD solutions, including theoretical methods and novel algorithms. The book covers various energy-aware design techniques, including data-dependence analysis techniques, memory size estimation methods, extensions of mapping approaches, and memory banking approaches. It shows how these techniques

Rad-hard embedded computers for nuclear robotics; Calculateurs durcis embarques pour la robotique nucleaire

Energy Technology Data Exchange (ETDEWEB)

Giraud, A; Joffre, F; Marceau, M; Robiolle, M; Brunet, J P; Mijuin, D

1994-12-31

For requirements of nuclear industries, it is necessary to use robots with embedded rad hard electronics and high level safety. The computer developed for french research program SYROCO is presented in this paper. (authors). 8 refs., 5 figs.

Integral Images: Efficient Algorithms for Their Computation and Storage in Resource-Constrained Embedded Vision Systems.

Science.gov (United States)

Ehsan, Shoaib; Clark, Adrian F; Naveed ur Rehman; McDonald-Maier, Klaus D

2015-07-10

The integral image, an intermediate image representation, has found extensive use in multi-scale local feature detection algorithms, such as Speeded-Up Robust Features (SURF), allowing fast computation of rectangular features at constant speed, independent of filter size. For resource-constrained real-time embedded vision systems, computation and storage of integral image presents several design challenges due to strict timing and hardware limitations. Although calculation of the integral image only consists of simple addition operations, the total number of operations is large owing to the generally large size of image data. Recursive equations allow substantial decrease in the number of operations but require calculation in a serial fashion. This paper presents two new hardware algorithms that are based on the decomposition of these recursive equations, allowing calculation of up to four integral image values in a row-parallel way without significantly increasing the number of operations. An efficient design strategy is also proposed for a parallel integral image computation unit to reduce the size of the required internal memory (nearly 35% for common HD video). Addressing the storage problem of integral image in embedded vision systems, the paper presents two algorithms which allow substantial decrease (at least 44.44%) in the memory requirements. Finally, the paper provides a case study that highlights the utility of the proposed architectures in embedded vision systems.

Integral Images: Efficient Algorithms for Their Computation and Storage in Resource-Constrained Embedded Vision Systems

Directory of Open Access Journals (Sweden)

Shoaib Ehsan

2015-07-01

Full Text Available The integral image, an intermediate image representation, has found extensive use in multi-scale local feature detection algorithms, such as Speeded-Up Robust Features (SURF, allowing fast computation of rectangular features at constant speed, independent of filter size. For resource-constrained real-time embedded vision systems, computation and storage of integral image presents several design challenges due to strict timing and hardware limitations. Although calculation of the integral image only consists of simple addition operations, the total number of operations is large owing to the generally large size of image data. Recursive equations allow substantial decrease in the number of operations but require calculation in a serial fashion. This paper presents two new hardware algorithms that are based on the decomposition of these recursive equations, allowing calculation of up to four integral image values in a row-parallel way without significantly increasing the number of operations. An efficient design strategy is also proposed for a parallel integral image computation unit to reduce the size of the required internal memory (nearly 35% for common HD video. Addressing the storage problem of integral image in embedded vision systems, the paper presents two algorithms which allow substantial decrease (at least 44.44% in the memory requirements. Finally, the paper provides a case study that highlights the utility of the proposed architectures in embedded vision systems.

Embedding potentials for excited states of embedded species

International Nuclear Information System (INIS)

Wesolowski, Tomasz A.

2014-01-01

Frozen-Density-Embedding Theory (FDET) is a formalism to obtain the upper bound of the ground-state energy of the total system and the corresponding embedded wavefunction by means of Euler-Lagrange equations [T. A. Wesolowski, Phys. Rev. A 77(1), 012504 (2008)]. FDET provides the expression for the embedding potential as a functional of the electron density of the embedded species, electron density of the environment, and the field generated by other charges in the environment. Under certain conditions, FDET leads to the exact ground-state energy and density of the whole system. Following Perdew-Levy theorem on stationary states of the ground-state energy functional, the other-than-ground-state stationary states of the FDET energy functional correspond to excited states. In the present work, we analyze such use of other-than-ground-state embedded wavefunctions obtained in practical calculations, i.e., when the FDET embedding potential is approximated. Three computational approaches based on FDET, that assure self-consistent excitation energy and embedded wavefunction dealing with the issue of orthogonality of embedded wavefunctions for different states in a different manner, are proposed and discussed

Small Spacecraft for Planetary Science

Science.gov (United States)

Baker, John; Castillo-Rogez, Julie; Bousquet, Pierre-W.; Vane, Gregg; Komarek, Tomas; Klesh, Andrew

2016-07-01

As planetary science continues to explore new and remote regions of the Solar system with comprehensive and more sophisticated payloads, small spacecraft offer the possibility for focused and more affordable science investigations. These small spacecraft or micro spacecraft (attitude control and determination, capable computer and data handling, and navigation are being met by technologies currently under development to be flown on CubeSats within the next five years. This paper will discuss how micro spacecraft offer an attractive alternative to accomplish specific science and technology goals and what relevant technologies are needed for these these types of spacecraft. Acknowledgements: Part of this work is being carried out at the Jet Propulsion Laboratory, California Institute of Technology under contract to NASA. Government sponsorship acknowledged.

Holomorphic Embedded Load Flow for Autonomous Spacecraft Power Systems, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — The proposed innovation advances the ability to apply the Holomorphic Embedding Load Flow Technology (HELM™) method to provide deterministic load flow modeling for...

Tensor Train Neighborhood Preserving Embedding

Science.gov (United States)

Wang, Wenqi; Aggarwal, Vaneet; Aeron, Shuchin

2018-05-01

In this paper, we propose a Tensor Train Neighborhood Preserving Embedding (TTNPE) to embed multi-dimensional tensor data into low dimensional tensor subspace. Novel approaches to solve the optimization problem in TTNPE are proposed. For this embedding, we evaluate novel trade-off gain among classification, computation, and dimensionality reduction (storage) for supervised learning. It is shown that compared to the state-of-the-arts tensor embedding methods, TTNPE achieves superior trade-off in classification, computation, and dimensionality reduction in MNIST handwritten digits and Weizmann face datasets.

Embedded Web Technology: Applying World Wide Web Standards to Embedded Systems

Science.gov (United States)

Ponyik, Joseph G.; York, David W.

2002-01-01

Embedded Systems have traditionally been developed in a highly customized manner. The user interface hardware and software along with the interface to the embedded system are typically unique to the system for which they are built, resulting in extra cost to the system in terms of development time and maintenance effort. World Wide Web standards have been developed in the passed ten years with the goal of allowing servers and clients to intemperate seamlessly. The client and server systems can consist of differing hardware and software platforms but the World Wide Web standards allow them to interface without knowing about the details of system at the other end of the interface. Embedded Web Technology is the merging of Embedded Systems with the World Wide Web. Embedded Web Technology decreases the cost of developing and maintaining the user interface by allowing the user to interface to the embedded system through a web browser running on a standard personal computer. Embedded Web Technology can also be used to simplify an Embedded System's internal network.

Modeling the fundamental characteristics and processes of the spacecraft functioning

Science.gov (United States)

Bazhenov, V. I.; Osin, M. I.; Zakharov, Y. V.

1986-01-01

The fundamental aspects of modeling of spacecraft characteristics by using computing means are considered. Particular attention is devoted to the design studies, the description of physical appearance of the spacecraft, and simulated modeling of spacecraft systems. The fundamental questions of organizing the on-the-ground spacecraft testing and the methods of mathematical modeling were presented.

Embedded Platforms for Computer Vision-based Advanced Driver Assistance Systems: a Survey

OpenAIRE

Velez, Gorka; Otaegui, Oihana

2015-01-01

Computer Vision, either alone or combined with other technologies such as radar or Lidar, is one of the key technologies used in Advanced Driver Assistance Systems (ADAS). Its role understanding and analysing the driving scene is of great importance as it can be noted by the number of ADAS applications that use this technology. However, porting a vision algorithm to an embedded automotive system is still very challenging, as there must be a trade-off between several design requisites. Further...

An Orbit Propagation Software for Mars Orbiting Spacecraft

Directory of Open Access Journals (Sweden)

Young-Joo Song

2004-12-01

Full Text Available An orbit propagation software for the Mars orbiting spacecraft has been developed and verified in preparations for the future Korean Mars missions. Dynamic model for Mars orbiting spacecraft has been studied, and Mars centered coordinate systems are utilized to express spacecraft state vectors. Coordinate corrections to the Mars centered coordinate system have been made to adjust the effects caused by Mars precession and nutation. After spacecraft enters Sphere of Influence (SOI of the Mars, the spacecraft experiences various perturbation effects as it approaches to Mars. Every possible perturbation effect is considered during integrations of spacecraft state vectors. The Mars50c gravity field model and the Mars-GRAM 2001 model are used to compute perturbation effects due to Mars gravity field and Mars atmospheric drag, respectively. To compute exact locations of other planets, JPL's DE405 ephemerides are used. Phobos and Deimos's ephemeris are computed using analytical method because their informations are not released with DE405. Mars Global Surveyor's mapping orbital data are used to verify the developed propagator performances. After one Martian day propagation (12 orbital periods, the results show about maximum ±5 meter errors, in every position state components(radial, cross-track and along-track, when compared to these from the Astrogator propagation in the Satellite Tool Kit. This result shows high reliability of the developed software which can be used to design near Mars missions for Korea, in future.

Computing the Dilation of Edge-Augmented Graphs Embedded in Metric Spaces

DEFF Research Database (Denmark)

Wulff-Nilsen, Christian

2008-01-01

Let G = (V,E) be an undirected graph with n vertices embedded in a metric space. We consider the problem of adding a shortcut edge in G that minimizes the dilation of the resulting graph. The fastest algorithm to date for this problem has O(n^4) running time and uses O(n^2) space. We show how...... to improve running time to O(n^3*log n) while maintaining quadratic space requirement. In fact, our algorithm not only determines the best shortcut but computes the dilation of G U {(u,v)} for every pair of distinct vertices u and v....

On the spacecraft attitude stabilization in the orbital frame

Directory of Open Access Journals (Sweden)

Antipov Kirill A.

2012-01-01

Full Text Available The paper deals with spacecraft in the circular near-Earth orbit. The spacecraft interacts with geomagnetic field by the moments of Lorentz and magnetic forces. The octupole approximation of the Earth’s magnetic field is accepted. The spacecraft electromagnetic parameters, namely the electrostatic charge moment of the first order and the eigen magnetic moment are the controlled quasiperiodic functions. The control algorithms for the spacecraft electromagnetic parameters, which allows to stabilize the spacecraft attitude position in the orbital frame are obtained. The stability of the spacecraft stabilized orientation is proved both analytically and by PC computations.

MIDN: A spacecraft Micro-dosimeter mission

International Nuclear Information System (INIS)

Pisacane, V. L.; Ziegler, J. F.; Nelson, M. E.; Caylor, M.; Flake, D.; Heyen, L.; Youngborg, E.; Rosenfeld, A. B.; Cucinotta, F.; Zaider, M.; Dicello, J. F.

2006-01-01

MIDN (Micro-dosimetry instrument) is a payload on the MidSTAR-I spacecraft (Midshipman Space Technology Applications Research) under development at the United States Naval Academy. MIDN is a solid-state system being designed and constructed to measure Micro-dosimetric spectra to determine radiation quality factors for space environments. Radiation is a critical threat to the health of astronauts and to the success of missions in low-Earth orbit and space exploration. The system will consist of three separate sensors, one external to the spacecraft, one internal and one embedded in polyethylene. Design goals are mass <3 kg and power <2 W. The MidSTAR-I mission in 2006 will provide an opportunity to evaluate a preliminary version of this system. Its low power and mass makes it useful for the International Space Station and manned and unmanned interplanetary missions as a real-time system to assess and alert astronauts to enhanced radiation environments. (authors)

Quantification of encapsulated bioburden in spacecraft polymer materials by cultivation-dependent and molecular methods.

Directory of Open Access Journals (Sweden)

Anja Bauermeister

Full Text Available Bioburden encapsulated in spacecraft polymers (such as adhesives and coatings poses a potential risk to jeopardize scientific exploration of other celestial bodies. This is particularly critical for spacecraft components intended for hard landing. So far, it remained unclear if polymers are indeed a source of microbial contamination. In addition, data with respect to survival of microbes during the embedding/polymerization process are sparse. In this study we developed testing strategies to quantitatively examine encapsulated bioburden in five different polymers used frequently and in large quantities on spaceflight hardware. As quantitative extraction of the bioburden from polymerized (solid materials did not prove feasible, contaminants were extracted from uncured precursors. Cultivation-based analyses revealed <0.1-2.5 colony forming units (cfu per cm3 polymer, whereas quantitative PCR-based detection of contaminants indicated considerably higher values, despite low DNA extraction efficiency. Results obtained from this approach reflect the most conservative proxy for encapsulated bioburden, as they give the maximum bioburden of the polymers irrespective of any additional physical and chemical stress occurring during polymerization. To address the latter issue, we deployed an embedding model to elucidate and monitor the physiological status of embedded Bacillus safensis spores in a cured polymer. Staining approaches using AlexaFluor succinimidyl ester 488 (AF488, propidium monoazide (PMA, CTC (5-cyano-2,3-diotolyl tetrazolium chloride demonstrated that embedded spores retained integrity, germination and cultivation ability even after polymerization of the adhesive Scotch-Weld 2216 B/A. Using the methods presented here, we were able to estimate the worst case contribution of encapsulated bioburden in different polymers to the bioburden of spacecraft. We demonstrated that spores were not affected by polymerization processes. Besides Planetary

Hard-real-time resource management for autonomous spacecraft

Science.gov (United States)

Gat, E.

2000-01-01

This paper describes tickets, a computational mechanism for hard-real-time autonomous resource management. Autonomous spacecraftcontrol can be considered abstractly as a computational process whose outputs are spacecraft commands.

A Resource-Aware Component Model for Embedded Systems

OpenAIRE

Vulgarakis, Aneta

2009-01-01

Embedded systems are microprocessor-based systems that cover a large range of computer systems from ultra small computer-based devices to large systems monitoring and controlling complex processes. The particular constraints that must be met by embedded systems, such as timeliness, resource-use efficiency, short time-to-market and low cost, coupled with the increasing complexity of embedded system software, demand technologies and processes that will tackle these issues. An attractive approac...

Embedded Systems Design with FPGAs

CERN Document Server

Pnevmatikatos, Dionisios; Sklavos, Nicolas

2013-01-01

This book presents methodologies for modern applications of embedded systems design, using field programmable gate array (FPGA) devices.  Coverage includes state-of-the-art research from academia and industry on a wide range of topics, including advanced electronic design automation (EDA), novel system architectures, embedded processors, arithmetic, dynamic reconfiguration and applications. Describes a variety of methodologies for modern embedded systems design;  Implements methodologies presented on FPGAs; Covers a wide variety of applications for reconfigurable embedded systems, including Bioinformatics, Communications and networking, Application acceleration, Medical solutions, Experiments for high energy physics, Astronomy, Aerospace, Biologically inspired systems and Computational fluid dynamics (CFD).

Software for Engineering Simulations of a Spacecraft

Science.gov (United States)

Shireman, Kirk; McSwain, Gene; McCormick, Bernell; Fardelos, Panayiotis

2005-01-01

Spacecraft Engineering Simulation II (SES II) is a C-language computer program for simulating diverse aspects of operation of a spacecraft characterized by either three or six degrees of freedom. A functional model in SES can include a trajectory flight plan; a submodel of a flight computer running navigational and flight-control software; and submodels of the environment, the dynamics of the spacecraft, and sensor inputs and outputs. SES II features a modular, object-oriented programming style. SES II supports event-based simulations, which, in turn, create an easily adaptable simulation environment in which many different types of trajectories can be simulated by use of the same software. The simulation output consists largely of flight data. SES II can be used to perform optimization and Monte Carlo dispersion simulations. It can also be used to perform simulations for multiple spacecraft. In addition to its generic simulation capabilities, SES offers special capabilities for space-shuttle simulations: for this purpose, it incorporates submodels of the space-shuttle dynamics and a C-language version of the guidance, navigation, and control components of the space-shuttle flight software.

Conceptual definition of Automated Power Systems Management. [for planetary spacecraft

Science.gov (United States)

Imamura, M. S.; Skelly, L.; Weiner, H.

1977-01-01

Automated Power Systems Management (APSM) is defined as the capability of a spacecraft power system to automatically perform monitoring, computational, command, and control functions without ground intervention. Power systems for future planetary spacecraft must have this capability because they must perform up to 10 years, and accommodate real-time changes in mission execution autonomously. Specific APSM functions include fault detection, isolation, and correction; system performance and load profile prediction; power system optimization; system checkout; and data storage and transmission control. This paper describes the basic method of implementing these specific functions. The APSM hardware includes a central power system computer and a processor dedicated to each major power system subassembly along with digital interface circuitry. The major payoffs anticipated are in enhancement of spacecraft reliability and life and reduction of overall spacecraft program cost.

Atrial Fibrillation Screening in Nonmetropolitan Areas Using a Telehealth Surveillance System With an Embedded Cloud-Computing Algorithm: Prospective Pilot Study

Science.gov (United States)

Chen, Ying-Hsien; Hung, Chi-Sheng; Huang, Ching-Chang; Hung, Yu-Chien

2017-01-01

Background Atrial fibrillation (AF) is a common form of arrhythmia that is associated with increased risk of stroke and mortality. Detecting AF before the first complication occurs is a recognized priority. No previous studies have examined the feasibility of undertaking AF screening using a telehealth surveillance system with an embedded cloud-computing algorithm; we address this issue in this study. Objective The objective of this study was to evaluate the feasibility of AF screening in nonmetropolitan areas using a telehealth surveillance system with an embedded cloud-computing algorithm. Methods We conducted a prospective AF screening study in a nonmetropolitan area using a single-lead electrocardiogram (ECG) recorder. All ECG measurements were reviewed on the telehealth surveillance system and interpreted by the cloud-computing algorithm and a cardiologist. The process of AF screening was evaluated with a satisfaction questionnaire. Results Between March 11, 2016 and August 31, 2016, 967 ECGs were recorded from 922 residents in nonmetropolitan areas. A total of 22 (2.4%, 22/922) residents with AF were identified by the physician’s ECG interpretation, and only 0.2% (2/967) of ECGs contained significant artifacts. The novel cloud-computing algorithm for AF detection had a sensitivity of 95.5% (95% CI 77.2%-99.9%) and specificity of 97.7% (95% CI 96.5%-98.5%). The overall satisfaction score for the process of AF screening was 92.1%. Conclusions AF screening in nonmetropolitan areas using a telehealth surveillance system with an embedded cloud-computing algorithm is feasible. PMID:28951384

Autonomous Multicamera Tracking on Embedded Smart Cameras

Directory of Open Access Journals (Sweden)

Bischof Horst

2007-01-01

Full Text Available There is currently a strong trend towards the deployment of advanced computer vision methods on embedded systems. This deployment is very challenging since embedded platforms often provide limited resources such as computing performance, memory, and power. In this paper we present a multicamera tracking method on distributed, embedded smart cameras. Smart cameras combine video sensing, processing, and communication on a single embedded device which is equipped with a multiprocessor computation and communication infrastructure. Our multicamera tracking approach focuses on a fully decentralized handover procedure between adjacent cameras. The basic idea is to initiate a single tracking instance in the multicamera system for each object of interest. The tracker follows the supervised object over the camera network, migrating to the camera which observes the object. Thus, no central coordination is required resulting in an autonomous and scalable tracking approach. We have fully implemented this novel multicamera tracking approach on our embedded smart cameras. Tracking is achieved by the well-known CamShift algorithm; the handover procedure is realized using a mobile agent system available on the smart camera network. Our approach has been successfully evaluated on tracking persons at our campus.

General rigid motion correction for computed tomography imaging based on locally linear embedding

Science.gov (United States)

Chen, Mianyi; He, Peng; Feng, Peng; Liu, Baodong; Yang, Qingsong; Wei, Biao; Wang, Ge

2018-02-01

The patient motion can damage the quality of computed tomography images, which are typically acquired in cone-beam geometry. The rigid patient motion is characterized by six geometric parameters and are more challenging to correct than in fan-beam geometry. We extend our previous rigid patient motion correction method based on the principle of locally linear embedding (LLE) from fan-beam to cone-beam geometry and accelerate the computational procedure with the graphics processing unit (GPU)-based all scale tomographic reconstruction Antwerp toolbox. The major merit of our method is that we need neither fiducial markers nor motion-tracking devices. The numerical and experimental studies show that the LLE-based patient motion correction is capable of calibrating the six parameters of the patient motion simultaneously, reducing patient motion artifacts significantly.

Time maintenance system for the BMDO MSX spacecraft

Science.gov (United States)

Hermes, Martin J.

1994-01-01

The Johns Hopkins University Applied Physics Laboratory (APL) is responsible for designing and implementing a clock maintenance system for the Ballistic Missile Defense Organizations (BMDO) Midcourse Space Experiment (MSX) spacecraft. The MSX spacecraft has an on-board clock that will be used to control execution of time-dependent commands and to time tag all science and housekeeping data received from the spacecraft. MSX mission objectives have dictated that this spacecraft time, UTC(MSX), maintain a required accuracy with respect to UTC(USNO) of +/- 10 ms with a +/- 1 ms desired accuracy. APL's atomic time standards and the downlinked spacecraft time were used to develop a time maintenance system that will estimate the current MSX clock time offset during an APL pass and make estimates of the clock's drift and aging using the offset estimates from many passes. Using this information, the clock's accuracy will be maintained by uplinking periodic clock correction commands. The resulting time maintenance system is a combination of offset measurement, command/telemetry, and mission planning hardware and computing assets. All assets provide necessary inputs for deciding when corrections to the MSX spacecraft clock must be made to maintain its required accuracy without inhibiting other mission objectives. The MSX time maintenance system is described as a whole and the clock offset measurement subsystem, a unique combination of precision time maintenance and measurement hardware controlled by a Macintosh computer, is detailed. Simulations show that the system estimates the MSX clock offset to less than+/- 33 microseconds.

Spacecraft Dynamics Should be Considered in Kalman Filter Attitude Estimation

Science.gov (United States)

Yang, Yaguang; Zhou, Zhiqiang

2016-01-01

Kalman filter based spacecraft attitude estimation has been used in some high-profile missions and has been widely discussed in literature. While some models in spacecraft attitude estimation include spacecraft dynamics, most do not. To our best knowledge, there is no comparison on which model is a better choice. In this paper, we discuss the reasons why spacecraft dynamics should be considered in the Kalman filter based spacecraft attitude estimation problem. We also propose a reduced quaternion spacecraft dynamics model which admits additive noise. Geometry of the reduced quaternion model and the additive noise are discussed. This treatment is more elegant in mathematics and easier in computation. We use some simulation example to verify our claims.

A Micro-Computed Tomography Technique to Study the Quality of Fibre Optics Embedded in Composite Materials

Directory of Open Access Journals (Sweden)

Gabriele Chiesura

2015-05-01

Full Text Available Quality of embedment of optical fibre sensors in carbon fibre-reinforced polymers plays an important role in the resultant properties of the composite, as well as for the correct monitoring of the structure. Therefore, availability of a tool able to check the optical fibre sensor-composite interaction becomes essential. High-resolution 3D X-ray Micro-Computed Tomography, or Micro-CT, is a relatively new non-destructive inspection technique which enables investigations of the internal structure of a sample without actually compromising its integrity. In this work the feasibility of inspecting the position, the orientation and, more generally, the quality of the embedment of an optical fibre sensor in a carbon fibre reinforced laminate at unit cell level have been proven.

Atrial Fibrillation Screening in Nonmetropolitan Areas Using a Telehealth Surveillance System With an Embedded Cloud-Computing Algorithm: Prospective Pilot Study.

Science.gov (United States)

Chen, Ying-Hsien; Hung, Chi-Sheng; Huang, Ching-Chang; Hung, Yu-Chien; Hwang, Juey-Jen; Ho, Yi-Lwun

2017-09-26

Atrial fibrillation (AF) is a common form of arrhythmia that is associated with increased risk of stroke and mortality. Detecting AF before the first complication occurs is a recognized priority. No previous studies have examined the feasibility of undertaking AF screening using a telehealth surveillance system with an embedded cloud-computing algorithm; we address this issue in this study. The objective of this study was to evaluate the feasibility of AF screening in nonmetropolitan areas using a telehealth surveillance system with an embedded cloud-computing algorithm. We conducted a prospective AF screening study in a nonmetropolitan area using a single-lead electrocardiogram (ECG) recorder. All ECG measurements were reviewed on the telehealth surveillance system and interpreted by the cloud-computing algorithm and a cardiologist. The process of AF screening was evaluated with a satisfaction questionnaire. Between March 11, 2016 and August 31, 2016, 967 ECGs were recorded from 922 residents in nonmetropolitan areas. A total of 22 (2.4%, 22/922) residents with AF were identified by the physician's ECG interpretation, and only 0.2% (2/967) of ECGs contained significant artifacts. The novel cloud-computing algorithm for AF detection had a sensitivity of 95.5% (95% CI 77.2%-99.9%) and specificity of 97.7% (95% CI 96.5%-98.5%). The overall satisfaction score for the process of AF screening was 92.1%. AF screening in nonmetropolitan areas using a telehealth surveillance system with an embedded cloud-computing algorithm is feasible. ©Ying-Hsien Chen, Chi-Sheng Hung, Ching-Chang Huang, Yu-Chien Hung, Juey-Jen Hwang, Yi-Lwun Ho. Originally published in JMIR Mhealth and Uhealth (http://mhealth.jmir.org), 26.09.2017.

A generalized modal shock spectra method for spacecraft loads analysis. [internal loads in a spacecraft structure subjected to a dynamic launch environment

Science.gov (United States)

Trubert, M.; Salama, M.

1979-01-01

Unlike an earlier shock spectra approach, generalization permits an accurate elastic interaction between the spacecraft and launch vehicle to obtain accurate bounds on the spacecraft response and structural loads. In addition, the modal response from a previous launch vehicle transient analysis with or without a dummy spacecraft - is exploited to define a modal impulse as a simple idealization of the actual forcing function. The idealized modal forcing function is then used to derive explicit expressions for an estimate of the bound on the spacecraft structural response and forces. Greater accuracy is achieved with the present method over the earlier shock spectra, while saving much computational effort over the transient analysis.

Polarizable Density Embedding

DEFF Research Database (Denmark)

Olsen, Jógvan Magnus Haugaard; Steinmann, Casper; Ruud, Kenneth

2015-01-01

We present a new QM/QM/MM-based model for calculating molecular properties and excited states of solute-solvent systems. We denote this new approach the polarizable density embedding (PDE) model and it represents an extension of our previously developed polarizable embedding (PE) strategy. The PDE...... model is a focused computational approach in which a core region of the system studied is represented by a quantum-chemical method, whereas the environment is divided into two other regions: an inner and an outer region. Molecules belonging to the inner region are described by their exact densities...

Automated constraint checking of spacecraft command sequences

Science.gov (United States)

Horvath, Joan C.; Alkalaj, Leon J.; Schneider, Karl M.; Spitale, Joseph M.; Le, Dang

1995-01-01

Robotic spacecraft are controlled by onboard sets of commands called "sequences." Determining that sequences will have the desired effect on the spacecraft can be expensive in terms of both labor and computer coding time, with different particular costs for different types of spacecraft. Specification languages and appropriate user interface to the languages can be used to make the most effective use of engineering validation time. This paper describes one specification and verification environment ("SAVE") designed for validating that command sequences have not violated any flight rules. This SAVE system was subsequently adapted for flight use on the TOPEX/Poseidon spacecraft. The relationship of this work to rule-based artificial intelligence and to other specification techniques is discussed, as well as the issues that arise in the transfer of technology from a research prototype to a full flight system.

Security Implications for Ultra-Low Power Configurable SoC FPAA Embedded Systems

Directory of Open Access Journals (Sweden)

Jennifer Hasler

2018-06-01

Full Text Available We discuss the impact of physical computing techniques to classifying network security issues for ultra-low power networked IoT devices. Physical computing approaches enable at least a factor of 1000 improvement in computational energy efficiency empowering a new generation of local computational structures for embedded IoT devices. These techniques offer computational capability to address network security concerns. This paper begins the discussion of security opportunities for, and issues using, FPAA devices for small embedded IoT platforms. These FPAAs enable devices often utilized for low-power context aware computation. Embedded FPAA devices have both positive Security attributes, as well as potential vulnerabilities. FPAA devices can be part of the resulting secure computation, such as implementing unique functions. FPAA devices can be used investigate security of analog/mixed signal capabilities. The paper concludes with summarizing key improvements for secure ultra-low power embedded FPAA devices.

T and D-Bench--Innovative Combined Support for Education and Research in Computer Architecture and Embedded Systems

Science.gov (United States)

Soares, S. N.; Wagner, F. R.

2011-01-01

Teaching and Design Workbench (T&D-Bench) is a framework aimed at education and research in the areas of computer architecture and embedded systems. It includes a set of features not found in other educational environments. This set of features is the result of an original combination of design requirements for T&D-Bench: that the…

Polarizable Density Embedding

DEFF Research Database (Denmark)

Reinholdt, Peter; Kongsted, Jacob; Olsen, Jógvan Magnus Haugaard

2017-01-01

We analyze the performance of the polarizable density embedding (PDE) model-a new multiscale computational approach designed for prediction and rationalization of general molecular properties of large and complex systems. We showcase how the PDE model very effectively handles the use of large...

Overview of SDCM - The Spacecraft Design and Cost Model

Science.gov (United States)

Ferebee, Melvin J.; Farmer, Jeffery T.; Andersen, Gregory C.; Flamm, Jeffery D.; Badi, Deborah M.

1988-01-01

The Spacecraft Design and Cost Model (SDCM) is a computer-aided design and analysis tool for synthesizing spacecraft configurations, integrating their subsystems, and generating information concerning on-orbit servicing and costs. SDCM uses a bottom-up method in which the cost and performance parameters for subsystem components are first calculated; the model then sums the contributions from individual components in order to obtain an estimate of sizes and costs for each candidate configuration within a selected spacecraft system. An optimum spacraft configuration can then be selected.

Numerical simulation of a hovering rotor using embedded grids

Science.gov (United States)

Duque, Earl-Peter N.; Srinivasan, Ganapathi R.

1992-01-01

The flow field for a rotor blade in hover was computed by numerically solving the compressible thin-layer Navier-Stokes equations on embedded grids. In this work, three embedded grids were used to discretize the flow field - one for the rotor blade and two to convect the rotor wake. The computations were performed at two hovering test conditions, for a two-bladed rectangular rotor of aspect ratio six. The results compare fairly with experiment and illustrates the use of embedded grids in solving helicopter type flow fields.

The data embedding method

Energy Technology Data Exchange (ETDEWEB)

Sandford, M.T. II; Bradley, J.N.; Handel, T.G.

1996-06-01

Data embedding is a new steganographic method for combining digital information sets. This paper describes the data embedding method and gives examples of its application using software written in the C-programming language. Sandford and Handel produced a computer program (BMPEMBED, Ver. 1.51 written for IBM PC/AT or compatible, MS/DOS Ver. 3.3 or later) that implements data embedding in an application for digital imagery. Information is embedded into, and extracted from, Truecolor or color-pallet images in Microsoft{reg_sign} bitmap (.BMP) format. Hiding data in the noise component of a host, by means of an algorithm that modifies or replaces the noise bits, is termed {open_quote}steganography.{close_quote} Data embedding differs markedly from conventional steganography, because it uses the noise component of the host to insert information with few or no modifications to the host data values or their statistical properties. Consequently, the entropy of the host data is affected little by using data embedding to add information. The data embedding method applies to host data compressed with transform, or {open_quote}lossy{close_quote} compression algorithms, as for example ones based on discrete cosine transform and wavelet functions. Analysis of the host noise generates a key required for embedding and extracting the auxiliary data from the combined data. The key is stored easily in the combined data. Images without the key cannot be processed to extract the embedded information. To provide security for the embedded data, one can remove the key from the combined data and manage it separately. The image key can be encrypted and stored in the combined data or transmitted separately as a ciphertext much smaller in size than the embedded data. The key size is typically ten to one-hundred bytes, and it is in data an analysis algorithm.

An embedded implementation based on adaptive filter bank for brain-computer interface systems.

Science.gov (United States)

Belwafi, Kais; Romain, Olivier; Gannouni, Sofien; Ghaffari, Fakhreddine; Djemal, Ridha; Ouni, Bouraoui

2018-07-15

Brain-computer interface (BCI) is a new communication pathway for users with neurological deficiencies. The implementation of a BCI system requires complex electroencephalography (EEG) signal processing including filtering, feature extraction and classification algorithms. Most of current BCI systems are implemented on personal computers. Therefore, there is a great interest in implementing BCI on embedded platforms to meet system specifications in terms of time response, cost effectiveness, power consumption, and accuracy. This article presents an embedded-BCI (EBCI) system based on a Stratix-IV field programmable gate array. The proposed system relays on the weighted overlap-add (WOLA) algorithm to perform dynamic filtering of EEG-signals by analyzing the event-related desynchronization/synchronization (ERD/ERS). The EEG-signals are classified, using the linear discriminant analysis algorithm, based on their spatial features. The proposed system performs fast classification within a time delay of 0.430 s/trial, achieving an average accuracy of 76.80% according to an offline approach and 80.25% using our own recording. The estimated power consumption of the prototype is approximately 0.7 W. Results show that the proposed EBCI system reduces the overall classification error rate for the three datasets of the BCI-competition by 5% compared to other similar implementations. Moreover, experiment shows that the proposed system maintains a high accuracy rate with a short processing time, a low power consumption, and a low cost. Performing dynamic filtering of EEG-signals using WOLA increases the recognition rate of ERD/ERS patterns of motor imagery brain activity. This approach allows to develop a complete prototype of a EBCI system that achieves excellent accuracy rates. Copyright © 2018 Elsevier B.V. All rights reserved.

Web Server Embedded System

Directory of Open Access Journals (Sweden)

Adharul Muttaqin

2014-07-01

Full Text Available Abstrak Embedded sistem saat ini menjadi perhatian khusus pada teknologi komputer, beberapa sistem operasi linux dan web server yang beraneka ragam juga sudah dipersiapkan untuk mendukung sistem embedded, salah satu aplikasi yang dapat digunakan dalam operasi pada sistem embedded adalah web server. Pemilihan web server pada lingkungan embedded saat ini masih jarang dilakukan, oleh karena itu penelitian ini dilakukan dengan menitik beratkan pada dua buah aplikasi web server yang tergolong memiliki fitur utama yang menawarkan “keringanan” pada konsumsi CPU maupun memori seperti Light HTTPD dan Tiny HTTPD. Dengan menggunakan parameter thread (users, ramp-up periods, dan loop count pada stress test embedded system, penelitian ini menawarkan solusi web server manakah diantara Light HTTPD dan Tiny HTTPD yang memiliki kecocokan fitur dalam penggunaan embedded sistem menggunakan beagleboard ditinjau dari konsumsi CPU dan memori. Hasil penelitian menunjukkan bahwa dalam hal konsumsi CPU pada beagleboard embedded system lebih disarankan penggunaan Light HTTPD dibandingkan dengan tiny HTTPD dikarenakan terdapat perbedaan CPU load yang sangat signifikan antar kedua layanan web tersebut Kata kunci: embedded system, web server Abstract Embedded systems are currently of particular concern in computer technology, some of the linux operating system and web server variegated also prepared to support the embedded system, one of the applications that can be used in embedded systems are operating on the web server. Selection of embedded web server on the environment is still rarely done, therefore this study was conducted with a focus on two web application servers belonging to the main features that offer a "lightness" to the CPU and memory consumption as Light HTTPD and Tiny HTTPD. By using the parameters of the thread (users, ramp-up periods, and loop count on a stress test embedded systems, this study offers a solution of web server which between the Light

Computers as Components Principles of Embedded Computing System Design

CERN Document Server

Wolf, Wayne

2008-01-01

This book was the first to bring essential knowledge on embedded systems technology and techniques under a single cover. This second edition has been updated to the state-of-the-art by reworking and expanding performance analysis with more examples and exercises, and coverage of electronic systems now focuses on the latest applications. Researchers, students, and savvy professionals schooled in hardware or software design, will value Wayne Wolf's integrated engineering design approach.The second edition gives a more comprehensive view of multiprocessors including VLIW and superscalar archite

Video-Game-Like Engine for Depicting Spacecraft Trajectories

Science.gov (United States)

Upchurch, Paul R.

2009-01-01

GoView is a video-game-like software engine, written in the C and C++ computing languages, that enables real-time, three-dimensional (3D)-appearing visual representation of spacecraft and trajectories (1) from any perspective; (2) at any spatial scale from spacecraft to Solar-system dimensions; (3) in user-selectable time scales; (4) in the past, present, and/or future; (5) with varying speeds; and (6) forward or backward in time. GoView constructs an interactive 3D world by use of spacecraft-mission data from pre-existing engineering software tools. GoView can also be used to produce distributable application programs for depicting NASA orbital missions on personal computers running the Windows XP, Mac OsX, and Linux operating systems. GoView enables seamless rendering of Cartesian coordinate spaces with programmable graphics hardware, whereas prior programs for depicting spacecraft trajectories variously require non-Cartesian coordinates and/or are not compatible with programmable hardware. GoView incorporates an algorithm for nonlinear interpolation between arbitrary reference frames, whereas the prior programs are restricted to special classes of inertial and non-inertial reference frames. Finally, whereas the prior programs present complex user interfaces requiring hours of training, the GoView interface provides guidance, enabling use without any training.

Rad-hard embedded computers for nuclear robotics

International Nuclear Information System (INIS)

Giraud, A.; Joffre, F.; Marceau, M.; Robiolle, M.; Brunet, J.P.; Mijuin, D.

1994-01-01

Nuclear industries require robots with embedded rad hard electronics and high reliability. The SYROCO research program allowed to perform efficient industrial prototypes, build according to MICADO architecture, and to design CADMOS architecture. MICADO architecture uses the auto healing property that have CMOS circuits when being switched off during irradiation. (D.L.). 8 refs., 5 figs

Robust Spacecraft Component Detection in Point Clouds

Directory of Open Access Journals (Sweden)

Quanmao Wei

2018-03-01

Full Text Available Automatic component detection of spacecraft can assist in on-orbit operation and space situational awareness. Spacecraft are generally composed of solar panels and cuboidal or cylindrical modules. These components can be simply represented by geometric primitives like plane, cuboid and cylinder. Based on this prior, we propose a robust automatic detection scheme to automatically detect such basic components of spacecraft in three-dimensional (3D point clouds. In the proposed scheme, cylinders are first detected in the iteration of the energy-based geometric model fitting and cylinder parameter estimation. Then, planes are detected by Hough transform and further described as bounded patches with their minimum bounding rectangles. Finally, the cuboids are detected with pair-wise geometry relations from the detected patches. After successive detection of cylinders, planar patches and cuboids, a mid-level geometry representation of the spacecraft can be delivered. We tested the proposed component detection scheme on spacecraft 3D point clouds synthesized by computer-aided design (CAD models and those recovered by image-based reconstruction, respectively. Experimental results illustrate that the proposed scheme can detect the basic geometric components effectively and has fine robustness against noise and point distribution density.

Robust Spacecraft Component Detection in Point Clouds.

Science.gov (United States)

Wei, Quanmao; Jiang, Zhiguo; Zhang, Haopeng

2018-03-21

Automatic component detection of spacecraft can assist in on-orbit operation and space situational awareness. Spacecraft are generally composed of solar panels and cuboidal or cylindrical modules. These components can be simply represented by geometric primitives like plane, cuboid and cylinder. Based on this prior, we propose a robust automatic detection scheme to automatically detect such basic components of spacecraft in three-dimensional (3D) point clouds. In the proposed scheme, cylinders are first detected in the iteration of the energy-based geometric model fitting and cylinder parameter estimation. Then, planes are detected by Hough transform and further described as bounded patches with their minimum bounding rectangles. Finally, the cuboids are detected with pair-wise geometry relations from the detected patches. After successive detection of cylinders, planar patches and cuboids, a mid-level geometry representation of the spacecraft can be delivered. We tested the proposed component detection scheme on spacecraft 3D point clouds synthesized by computer-aided design (CAD) models and those recovered by image-based reconstruction, respectively. Experimental results illustrate that the proposed scheme can detect the basic geometric components effectively and has fine robustness against noise and point distribution density.

Deep Space Networking Experiments on the EPOXI Spacecraft

Science.gov (United States)

Jones, Ross M.

2011-01-01

NASA's Space Communications & Navigation Program within the Space Operations Directorate is operating a program to develop and deploy Disruption Tolerant Networking [DTN] technology for a wide variety of mission types by the end of 2011. DTN is an enabling element of the Interplanetary Internet where terrestrial networking protocols are generally unsuitable because they rely on timely and continuous end-to-end delivery of data and acknowledgments. In fall of 2008 and 2009 and 2011 the Jet Propulsion Laboratory installed and tested essential elements of DTN technology on the Deep Impact spacecraft. These experiments, called Deep Impact Network Experiment (DINET 1) were performed in close cooperation with the EPOXI project which has responsibility for the spacecraft. The DINET 1 software was installed on the backup software partition on the backup flight computer for DINET 1. For DINET 1, the spacecraft was at a distance of about 15 million miles (24 million kilometers) from Earth. During DINET 1 300 images were transmitted from the JPL nodes to the spacecraft. Then, they were automatically forwarded from the spacecraft back to the JPL nodes, exercising DTN's bundle origination, transmission, acquisition, dynamic route computation, congestion control, prioritization, custody transfer, and automatic retransmission procedures, both on the spacecraft and on the ground, over a period of 27 days. The first DINET 1 experiment successfully validated many of the essential elements of the DTN protocols. DINET 2 demonstrated: 1) additional DTN functionality, 2) automated certain tasks which were manually implemented in DINET 1 and 3) installed the ION SW on nodes outside of JPL. DINET 3 plans to: 1) upgrade the LTP convergence-layer adapter to conform to the international LTP CL specification, 2) add convergence-layer "stewardship" procedures and 3) add the BSP security elements [PIB & PCB]. This paper describes the planning and execution of the flight experiment and the

Teaching Embedded System Concepts for Technological Literacy

Science.gov (United States)

Winzker, M.; Schwandt, A.

2011-01-01

A basic understanding of technology is recognized as important knowledge even for students not connected with engineering and computer science. This paper shows that embedded system concepts can be taught in a technological literacy course. An embedded system teaching block that has been used in an electronics module for non-engineers is…

Small private key MQPKS on an embedded microprocessor.

Science.gov (United States)

Seo, Hwajeong; Kim, Jihyun; Choi, Jongseok; Park, Taehwan; Liu, Zhe; Kim, Howon

2014-03-19

Multivariate quadratic (MQ) cryptography requires the use of long public and private keys to ensure a sufficient security level, but this is not favorable to embedded systems, which have limited system resources. Recently, various approaches to MQ cryptography using reduced public keys have been studied. As a result of this, at CHES2011 (Cryptographic Hardware and Embedded Systems, 2011), a small public key MQ scheme, was proposed, and its feasible implementation on an embedded microprocessor was reported at CHES2012. However, the implementation of a small private key MQ scheme was not reported. For efficient implementation, random number generators can contribute to reduce the key size, but the cost of using a random number generator is much more complex than computing MQ on modern microprocessors. Therefore, no feasible results have been reported on embedded microprocessors. In this paper, we propose a feasible implementation on embedded microprocessors for a small private key MQ scheme using a pseudo-random number generator and hash function based on a block-cipher exploiting a hardware Advanced Encryption Standard (AES) accelerator. To speed up the performance, we apply various implementation methods, including parallel computation, on-the-fly computation, optimized logarithm representation, vinegar monomials and assembly programming. The proposed method reduces the private key size by about 99.9% and boosts signature generation and verification by 5.78% and 12.19% than previous results in CHES2012.

Small Private Key PKS on an Embedded Microprocessor

Science.gov (United States)

Seo, Hwajeong; Kim, Jihyun; Choi, Jongseok; Park, Taehwan; Liu, Zhe; Kim, Howon

2014-01-01

Multivariate quadratic ( ) cryptography requires the use of long public and private keys to ensure a sufficient security level, but this is not favorable to embedded systems, which have limited system resources. Recently, various approaches to cryptography using reduced public keys have been studied. As a result of this, at CHES2011 (Cryptographic Hardware and Embedded Systems, 2011), a small public key scheme, was proposed, and its feasible implementation on an embedded microprocessor was reported at CHES2012. However, the implementation of a small private key scheme was not reported. For efficient implementation, random number generators can contribute to reduce the key size, but the cost of using a random number generator is much more complex than computing on modern microprocessors. Therefore, no feasible results have been reported on embedded microprocessors. In this paper, we propose a feasible implementation on embedded microprocessors for a small private key scheme using a pseudo-random number generator and hash function based on a block-cipher exploiting a hardware Advanced Encryption Standard (AES) accelerator. To speed up the performance, we apply various implementation methods, including parallel computation, on-the-fly computation, optimized logarithm representation, vinegar monomials and assembly programming. The proposed method reduces the private key size by about 99.9% and boosts signature generation and verification by 5.78% and 12.19% than previous results in CHES2012. PMID:24651722

A Fault-tolerant RISC Microprocessor for Spacecraft Applications

Science.gov (United States)

Timoc, Constantin; Benz, Harry

1990-01-01

Viewgraphs on a fault-tolerant RISC microprocessor for spacecraft applications are presented. Topics covered include: reduced instruction set computer; fault tolerant registers; fault tolerant ALU; and double rail CMOS logic.

STFTP: Secure TFTP Protocol for Embedded Multi-Agent Systems Communication

Directory of Open Access Journals (Sweden)

ZAGAR, D.

2013-05-01

Full Text Available Today's embedded systems have evolved into multipurpose devices moving towards an embedded multi-agent system (MAS infrastructure. With the involvement of MAS in embedded systems, one remaining issues is establishing communication between agents in low computational power and low memory embedded systems without present Embedded Operating System (EOS. One solution is the extension of an outdated Trivial File Transfer Protocol (TFTP. The main advantage of using TFTP in embedded systems is the easy implementation. However, the problem at hand is the overall lack of security mechanisms in TFTP. This paper proposes an extension to the existing TFTP in a form of added security mechanisms: STFTP. The authentication is proposed using Digest Access Authentication process whereas the data encryption can be performed by various cryptographic algorithms. The proposal is experimentally tested using two embedded systems based on micro-controller architecture. Communication is analyzed for authentication, data rate and transfer time versus various data encryption ciphers and files sizes. STFTP results in an expected drop in performance, which is in the range of similar encryption algorithms. The system could be improved by using embedded systems of higher computational power or by the use of hardware encryption modules.

Intelligence for embedded systems a methodological approach

CERN Document Server

Alippi, Cesare

2014-01-01

Addressing current issues of which any engineer or computer scientist should be aware, this monograph is a response to the need to adopt a new computational paradigm as the methodological basis for designing pervasive embedded systems with sensor capabilities. The requirements of this paradigm are to control complexity, to limit cost and energy consumption, and to provide adaptation and cognition abilities allowing the embedded system to interact proactively with the real world. The quest for such intelligence requires the formalization of a new generation of intelligent systems able to exploit advances in digital architectures and in sensing technologies. The book sheds light on the theory behind intelligence for embedded systems with specific focus on: ·        robustness (the robustness of a computational flow and its evaluation); ·        intelligence (how to mimic the adaptation and cognition abilities of the human brain), ·        the capacity to learn in non-stationary and evolv...

Comparison of Pilot Symbol Embedded Channel Estimation Algorithms

Directory of Open Access Journals (Sweden)

P. Kadlec

2009-12-01

Full Text Available In the paper, algorithms of the pilot symbol embedded channel estimation are compared. Attention is turned to the Least Square (LS channel estimation and the Sliding Correlator (SC algorithm. Both algorithms are implemented in Matlab to estimate the Channel Impulse Response (CIR of a channel exhibiting multi-path propagation. Algorithms are compared from the viewpoint of computational demands, influence of the Additive White Gaussian Noise (AWGN, an embedded pilot symbol and a computed CIR over the estimation error.

The Use of Video-Gaming Devices as a Motivation for Learning Embedded Systems Programming

Science.gov (United States)

Gonzalez, J.; Pomares, H.; Damas, M.; Garcia-Sanchez,P.; Rodriguez-Alvarez, M.; Palomares, J. M.

2013-01-01

As embedded systems are becoming prevalent in everyday life, many universities are incorporating embedded systems-related courses in their undergraduate curricula. However, it is not easy to motivate students in such courses since they conceive of embedded systems as bizarre computing elements, different from the personal computers with which they…

Mesh Network Architecture for Enabling Inter-Spacecraft Communication

Science.gov (United States)

Becker, Christopher; Merrill, Garrick

2017-01-01

To enable communication between spacecraft operating in a formation or small constellation, a mesh network architecture was developed and tested using a time division multiple access (TDMA) communication scheme. The network is designed to allow for the exchange of telemetry and other data between spacecraft to enable collaboration between small spacecraft. The system uses a peer-to-peer topology with no central router, so that it does not have a single point of failure. The mesh network is dynamically configurable to allow for addition and subtraction of new spacecraft into the communication network. Flight testing was performed using an unmanned aerial system (UAS) formation acting as a spacecraft analogue and providing a stressing environment to prove mesh network performance. The mesh network was primarily devised to provide low latency, high frequency communication but is flexible and can also be configured to provide higher bandwidth for applications desiring high data throughput. The network includes a relay functionality that extends the maximum range between spacecraft in the network by relaying data from node to node. The mesh network control is implemented completely in software making it hardware agnostic, thereby allowing it to function with a wide variety of existing radios and computing platforms..

Small Private Key MQPKS on an Embedded Microprocessor

Directory of Open Access Journals (Sweden)

Hwajeong Seo

2014-03-01

Full Text Available Multivariate quadratic (MQ cryptography requires the use of long public and private keys to ensure a sufficient security level, but this is not favorable to embedded systems, which have limited system resources. Recently, various approaches to MQ cryptography using reduced public keys have been studied. As a result of this, at CHES2011 (Cryptographic Hardware and Embedded Systems, 2011, a small public key MQ scheme, was proposed, and its feasible implementation on an embedded microprocessor was reported at CHES2012. However, the implementation of a small private key MQ scheme was not reported. For efficient implementation, random number generators can contribute to reduce the key size, but the cost of using a random number generator is much more complex than computing MQ on modern microprocessors. Therefore, no feasible results have been reported on embedded microprocessors. In this paper, we propose a feasible implementation on embedded microprocessors for a small private key MQ scheme using a pseudo-random number generator and hash function based on a block-cipher exploiting a hardware Advanced Encryption Standard (AES accelerator. To speed up the performance, we apply various implementation methods, including parallel computation, on-the-fly computation, optimized logarithm representation, vinegar monomials and assembly programming. The proposed method reduces the private key size by about 99.9% and boosts signature generation and verification by 5.78% and 12.19% than previous results in CHES2012.

OpenVX-based Python Framework for real-time cross platform acceleration of embedded computer vision applications

Directory of Open Access Journals (Sweden)

Ori Heimlich

2016-11-01

Full Text Available Embedded real-time vision applications are being rapidly deployed in a large realm of consumer electronics, ranging from automotive safety to surveillance systems. However, the relatively limited computational power of embedded platforms is considered as a bottleneck for many vision applications, necessitating optimization. OpenVX is a standardized interface, released in late 2014, in an attempt to provide both system and kernel level optimization to vision applications. With OpenVX, Vision processing are modeled with coarse-grained data flow graphs, which can be optimized and accelerated by the platform implementer. Current full implementations of OpenVX are given in the programming language C, which does not support advanced programming paradigms such as object-oriented, imperative and functional programming, nor does it have runtime or type-checking. Here we present a python-based full Implementation of OpenVX, which eliminates much of the discrepancies between the object-oriented paradigm used by many modern applications and the native C implementations. Our open-source implementation can be used for rapid development of OpenVX applications in embedded platforms. Demonstration includes static and real-time image acquisition and processing using a Raspberry Pi and a GoPro camera. Code is given as supplementary information. Code project and linked deployable virtual machine are located on GitHub: https://github.com/NBEL-lab/PythonOpenVX.

Scheduling of network access for feedback-based embedded systems

Science.gov (United States)

Liberatore, Vincenzo

2002-07-01

nd communication capabilities. Examples range from smart dust embedded in building materials to networks of appliances in the home. Embedded devices will be deployed in unprecedented numbers, will enable pervasive distributed computing, and will radically change the way people interact with the surrounding environment [EGH00a]. The paper targets embedded systems and their real-time (RT) communication requirements. RT requirements arise from the

Operating system concepts for embedded multicores

OpenAIRE

Horst, Oliver; Schmidt, Adriaan

2014-01-01

Currently we can see an increasing adoption of multi-core platforms in the area of embedded systems. While these new hardware platforms offer the potential to satisfy the ever increasing demand for computational power, they pose considerable challenges with regard to software development. This affects the application software itself, but also the system design and architecture. Here, we address the consequences for operating system architecture in embedded systems. After dis-cussing current a...

Parametric embedding for class visualization.

Science.gov (United States)

Iwata, Tomoharu; Saito, Kazumi; Ueda, Naonori; Stromsten, Sean; Griffiths, Thomas L; Tenenbaum, Joshua B

2007-09-01

We propose a new method, parametric embedding (PE), that embeds objects with the class structure into a low-dimensional visualization space. PE takes as input a set of class conditional probabilities for given data points and tries to preserve the structure in an embedding space by minimizing a sum of Kullback-Leibler divergences, under the assumption that samples are generated by a gaussian mixture with equal covariances in the embedding space. PE has many potential uses depending on the source of the input data, providing insight into the classifier's behavior in supervised, semisupervised, and unsupervised settings. The PE algorithm has a computational advantage over conventional embedding methods based on pairwise object relations since its complexity scales with the product of the number of objects and the number of classes. We demonstrate PE by visualizing supervised categorization of Web pages, semisupervised categorization of digits, and the relations of words and latent topics found by an unsupervised algorithm, latent Dirichlet allocation.

Miniaturized star tracker for micro spacecraft with high angular rate

Science.gov (United States)

Li, Jianhua; Li, Zhifeng; Niu, Zhenhong; Liu, Jiaqi

2017-10-01

There is a clear need for miniaturized, lightweight, accurate and inexpensive star tracker for spacecraft with large anglar rate. To face these new constraints, the Beijing Institute of Space Long March Vehicle has designed, built and flown a low cost miniaturized star tracker that provides autonomous ("Lost in Space") inertial attitude determination, 2 Hz 3-axis star tracking, and digital imaging with embedded compression. Detector with high sensitivity is adopted to meet the dynamic and miniature requirement. A Sun and Moon avoiding method based on the calculation of Sun and Moon's vector by astronomical theory is proposed. The produced prototype weight 0.84kg, and can be used for a spacecraft with 6°/s anglar rate. The average angle measure error is less than 43 arc second. The ground verification and application of the star tracker during the pick-up flight test showed that the capability of the product meet the requirement.

Large-Scale Spacecraft Fire Safety Tests

Science.gov (United States)

Urban, David; Ruff, Gary A.; Ferkul, Paul V.; Olson, Sandra; Fernandez-Pello, A. Carlos; T'ien, James S.; Torero, Jose L.; Cowlard, Adam J.; Rouvreau, Sebastien; Minster, Olivier;

Telemetry Timing Analysis for Image Reconstruction of Kompsat Spacecraft

Directory of Open Access Journals (Sweden)

Jin-Ho Lee

2000-06-01

Full Text Available The KOMPSAT (KOrea Multi-Purpose SATellite has two optical imaging instruments called EOC (Electro-Optical Camera and OSMI (Ocean Scanning Multispectral Imager. The image data of these instruments are transmitted to ground station and restored correctly after post-processing with the telemetry data transferred from KOMPSAT spacecraft. The major timing information of the KOMPSAT is OBT (On-Board Time which is formatted by the on-board computer of the spacecraft, based on 1Hz sync. pulse coming from the GPS receiver involved. The OBT is transmitted to ground station with the house-keeping telemetry data of the spacecraft while it is distributed to the instruments via 1553B data bus for synchronization during imaging and formatting. The timing information contained in the spacecraft telemetry data would have direct relation to the image data of the instruments, which should be well explained to get a more accurate image. This paper addresses the timing analysis of the KOMPSAT spacecraft and instruments, including the gyro data timing analysis for the correct restoration of the EOC and OSMI image data at ground station.

Static Schedulers for Embedded Real-Time Systems

Science.gov (United States)

1989-12-01

Because of the need for having efficient scheduling algorithms in large scale real time systems , software engineers put a lot of effort on developing...provide static schedulers for he Embedded Real Time Systems with single processor using Ada programming language. The independent nonpreemptable...support the Computer Aided Rapid Prototyping for Embedded Real Time Systems so that we determine whether the system, as designed, meets the required

Spacecraft radiator systems

Science.gov (United States)

Anderson, Grant A. (Inventor)

2012-01-01

A spacecraft radiator system designed to provide structural support to the spacecraft. Structural support is provided by the geometric "crescent" form of the panels of the spacecraft radiator. This integration of radiator and structural support provides spacecraft with a semi-monocoque design.

Evaluation of spacecraft technology programs (effects on communication satellite business ventures), volume 2

Science.gov (United States)

Greenburg, J. S.; Kaplan, M.; Fishman, J.; Hopkins, C.

1985-01-01

The computational procedures used in the evaluation of spacecraft technology programs that impact upon commercial communication satellite operations are discussed. Computer programs and data bases are described.

Proceedings of the High Performance Embedded Computing Workshop (HPEC 2006) (10th). Held in Lexington, Massachusetts on September 19-21, 2006 (CD-ROM)

National Research Council Canada - National Science Library

Kepner, Jeremy

2007-01-01

...: 1 CD-ROM; 4 3/4 in.; 78.3 MB. ABSTRACT: The High-Performance Embedded Computing (HPEC) technical committee announced the tenth annual HPEC Workshop held in September 2006 at MIT Lincoln Laboratory in Lexington, MA...

Large Scale Experiments on Spacecraft Fire Safety

Science.gov (United States)

Urban, David; Ruff, Gary A.; Minster, Olivier; Fernandez-Pello, A. Carlos; Tien, James S.; Torero, Jose L.; Legros, Guillaume; Eigenbrod, Christian; Smirnov, Nickolay; Fujita, Osamu;

Real-time depth processing for embedded platforms

Science.gov (United States)

Rahnama, Oscar; Makarov, Aleksej; Torr, Philip

2017-05-01

Obtaining depth information of a scene is an important requirement in many computer-vision and robotics applications. For embedded platforms, passive stereo systems have many advantages over their active counterparts (i.e. LiDAR, Infrared). They are power efficient, cheap, robust to lighting conditions and inherently synchronized to the RGB images of the scene. However, stereo depth estimation is a computationally expensive task that operates over large amounts of data. For embedded applications which are often constrained by power consumption, obtaining accurate results in real-time is a challenge. We demonstrate a computationally and memory efficient implementation of a stereo block-matching algorithm in FPGA. The computational core achieves a throughput of 577 fps at standard VGA resolution whilst consuming less than 3 Watts of power. The data is processed using an in-stream approach that minimizes memory-access bottlenecks and best matches the raster scan readout of modern digital image sensors.

Guidance and control of swarms of spacecraft

Science.gov (United States)

Morgan, Daniel James

There has been considerable interest in formation flying spacecraft due to their potential to perform certain tasks at a cheaper cost than monolithic spacecraft. Formation flying enables the use of smaller, cheaper spacecraft that distribute the risk of the mission. Recently, the ideas of formation flying have been extended to spacecraft swarms made up of hundreds to thousands of 100-gram-class spacecraft known as femtosatellites. The large number of spacecraft and limited capabilities of each individual spacecraft present a significant challenge in guidance, navigation, and control. This dissertation deals with the guidance and control algorithms required to enable the flight of spacecraft swarms. The algorithms developed in this dissertation are focused on achieving two main goals: swarm keeping and swarm reconfiguration. The objectives of swarm keeping are to maintain bounded relative distances between spacecraft, prevent collisions between spacecraft, and minimize the propellant used by each spacecraft. Swarm reconfiguration requires the transfer of the swarm to a specific shape. Like with swarm keeping, minimizing the propellant used and preventing collisions are the main objectives. Additionally, the algorithms required for swarm keeping and swarm reconfiguration should be decentralized with respect to communication and computation so that they can be implemented on femtosats, which have limited hardware capabilities. The algorithms developed in this dissertation are concerned with swarms located in low Earth orbit. In these orbits, Earth oblateness and atmospheric drag have a significant effect on the relative motion of the swarm. The complicated dynamic environment of low Earth orbits further complicates the swarm-keeping and swarm-reconfiguration problems. To better develop and test these algorithms, a nonlinear, relative dynamic model with J2 and drag perturbations is developed. This model is used throughout this dissertation to validate the algorithms

An Overview of Reconfigurable Hardware in Embedded Systems

Directory of Open Access Journals (Sweden)

Wenyin Fu

2006-09-01

Full Text Available Over the past few years, the realm of embedded systems has expanded to include a wide variety of products, ranging from digital cameras, to sensor networks, to medical imaging systems. Consequently, engineers strive to create ever smaller and faster products, many of which have stringent power requirements. Coupled with increasing pressure to decrease costs and time-to-market, the design constraints of embedded systems pose a serious challenge to embedded systems designers. Reconfigurable hardware can provide a flexible and efficient platform for satisfying the area, performance, cost, and power requirements of many embedded systems. This article presents an overview of reconfigurable computing in embedded systems, in terms of benefits it can provide, how it has already been used, design issues, and hurdles that have slowed its adoption.

Toward autonomous spacecraft

Science.gov (United States)

Fogel, L. J.; Calabrese, P. G.; Walsh, M. J.; Owens, A. J.

1982-01-01

Ways in which autonomous behavior of spacecraft can be extended to treat situations wherein a closed loop control by a human may not be appropriate or even possible are explored. Predictive models that minimize mean least squared error and arbitrary cost functions are discussed. A methodology for extracting cyclic components for an arbitrary environment with respect to usual and arbitrary criteria is developed. An approach to prediction and control based on evolutionary programming is outlined. A computer program capable of predicting time series is presented. A design of a control system for a robotic dense with partially unknown physical properties is presented.

Comprehensive Fault Tolerance and Science-Optimal Attitude Planning for Spacecraft Applications

Science.gov (United States)

Nasir, Ali

Spacecraft operate in a harsh environment, are costly to launch, and experience unavoidable communication delay and bandwidth constraints. These factors motivate the need for effective onboard mission and fault management. This dissertation presents an integrated framework to optimize science goal achievement while identifying and managing encountered faults. Goal-related tasks are defined by pointing the spacecraft instrumentation toward distant targets of scientific interest. The relative value of science data collection is traded with risk of failures to determine an optimal policy for mission execution. Our major innovation in fault detection and reconfiguration is to incorporate fault information obtained from two types of spacecraft models: one based on the dynamics of the spacecraft and the second based on the internal composition of the spacecraft. For fault reconfiguration, we consider possible changes in both dynamics-based control law configuration and the composition-based switching configuration. We formulate our problem as a stochastic sequential decision problem or Markov Decision Process (MDP). To avoid the computational complexity involved in a fully-integrated MDP, we decompose our problem into multiple MDPs. These MDPs include planning MDPs for different fault scenarios, a fault detection MDP based on a logic-based model of spacecraft component and system functionality, an MDP for resolving conflicts between fault information from the logic-based model and the dynamics-based spacecraft models" and the reconfiguration MDP that generates a policy optimized over the relative importance of the mission objectives versus spacecraft safety. Approximate Dynamic Programming (ADP) methods for the decomposition of the planning and fault detection MDPs are applied. To show the performance of the MDP-based frameworks and ADP methods, a suite of spacecraft attitude planning case studies are described. These case studies are used to analyze the content and

Software for Embedded Control Systems

NARCIS (Netherlands)

Broenink, Johannes F.; Hilderink, G.H.; Jovanovic, D.S.

2001-01-01

The research of our team deals with the realization of control schemes on digital computers. As such the emphasis is on embedded control software implementation. Applications are in the field of mechatronic devices, using a mechatronic design approach (the integrated and optimal design of a

The art of programming embedded systems

CERN Document Server

Ganssle, Jack

1992-01-01

Embedded systems are products such as microwave ovens, cars, and toys that rely on an internal microprocessor. This book is oriented toward the design engineer or programmer who writes the computer code for such a system. There are a number of problems specific to the embedded systems designer, and this book addresses them and offers practical solutions.Key Features* Offers cookbook routines, algorithms, and design techniques* Includes tips for handling debugging management and testing* Explores the philosophy of tightly coupling software and hardware in programming and dev

Bootstrap embedding: An internally consistent fragment-based method

Energy Technology Data Exchange (ETDEWEB)

Welborn, Matthew; Tsuchimochi, Takashi; Van Voorhis, Troy [Department of Chemistry, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139 (United States)

2016-08-21

Strong correlation poses a difficult problem for electronic structure theory, with computational cost scaling quickly with system size. Fragment embedding is an attractive approach to this problem. By dividing a large complicated system into smaller manageable fragments “embedded” in an approximate description of the rest of the system, we can hope to ameliorate the steep cost of correlated calculations. While appealing, these methods often converge slowly with fragment size because of small errors at the boundary between fragment and bath. We describe a new electronic embedding method, dubbed “Bootstrap Embedding,” a self-consistent wavefunction-in-wavefunction embedding theory that uses overlapping fragments to improve the description of fragment edges. We apply this method to the one dimensional Hubbard model and a translationally asymmetric variant, and find that it performs very well for energies and populations. We find Bootstrap Embedding converges rapidly with embedded fragment size, overcoming the surface-area-to-volume-ratio error typical of many embedding methods. We anticipate that this method may lead to a low-scaling, high accuracy treatment of electron correlation in large molecular systems.

Data combinations accounting for LISA spacecraft motion

International Nuclear Information System (INIS)

Shaddock, Daniel A.; Tinto, Massimo; Estabrook, Frank B.; Armstrong, J.W.

2003-01-01

The laser interferometer space antenna is an array of three spacecraft in an approximately equilateral triangle configuration which will be used as a low-frequency gravitational wave detector. We present here new generalizations of the Michelson- and Sagnac-type time-delay interferometry data combinations. These combinations cancel laser phase noise in the presence of different up and down propagation delays in each arm of the array, and slowly varying systematic motion of the spacecraft. The gravitational wave sensitivities of these generalized combinations are the same as previously computed for the stationary cases, although the combinations are now more complicated. We introduce a diagrammatic representation to illustrate that these combinations are actually synthesized equal-arm interferometers

Autonomous Spacecraft Communication Interface for Load Planning

Science.gov (United States)

Dever, Timothy P.; May, Ryan D.; Morris, Paul H.

2014-01-01

Ground-based controllers can remain in continuous communication with spacecraft in low Earth orbit (LEO) with near-instantaneous communication speeds. This permits near real-time control of all of the core spacecraft systems by ground personnel. However, as NASA missions move beyond LEO, light-time communication delay issues, such as time lag and low bandwidth, will prohibit this type of operation. As missions become more distant, autonomous control of manned spacecraft will be required. The focus of this paper is the power subsystem. For present missions, controllers on the ground develop a complete schedule of power usage for all spacecraft components. This paper presents work currently underway at NASA to develop an architecture for an autonomous spacecraft, and focuses on the development of communication between the Mission Manager and the Autonomous Power Controller. These two systems must work together in order to plan future load use and respond to unanticipated plan deviations. Using a nominal spacecraft architecture and prototype versions of these two key components, a number of simulations are run under a variety of operational conditions, enabling development of content and format of the messages necessary to achieve the desired goals. The goals include negotiation of a load schedule that meets the global requirements (contained in the Mission Manager) and local power system requirements (contained in the Autonomous Power Controller), and communication of off-plan disturbances that arise while executing a negotiated plan. The message content is developed in two steps: first, a set of rapid-prototyping "paper" simulations are preformed; then the resultant optimized messages are codified for computer communication for use in automated testing.

Building professionalism and employability skills: embedding employer engagement within first-year computing modules

Science.gov (United States)

Hanna, Philip; Allen, Angela; Kane, Russell; Anderson, Neil; McGowan, Aidan; Collins, Matthew; Hutchison, Malcolm

2015-07-01

This paper outlines a means of improving the employability skills of first-year university students through a closely integrated model of employer engagement within computer science modules. The outlined approach illustrates how employability skills, including communication, teamwork and time management skills, can be contextualised in a manner that directly relates to student learning but can still be linked forward into employment. The paper tests the premise that developing employability skills early within the curriculum will result in improved student engagement and learning within later modules. The paper concludes that embedding employer participation within first-year models can help relate a distant notion of employability into something of more immediate relevance in terms of how students can best approach learning. Further, by enhancing employability skills early within the curriculum, it becomes possible to improve academic attainment within later modules.

An Embedded Reconfigurable Logic Module

Science.gov (United States)

Tucker, Jerry H.; Klenke, Robert H.; Shams, Qamar A. (Technical Monitor)

2002-01-01

A Miniature Embedded Reconfigurable Computer and Logic (MERCAL) module has been developed and verified. MERCAL was designed to be a general-purpose, universal module that that can provide significant hardware and software resources to meet the requirements of many of today's complex embedded applications. This is accomplished in the MERCAL module by combining a sub credit card size PC in a DIMM form factor with a XILINX Spartan I1 FPGA. The PC has the ability to download program files to the FPGA to configure it for different hardware functions and to transfer data to and from the FPGA via the PC's ISA bus during run time. The MERCAL module combines, in a compact package, the computational power of a 133 MHz PC with up to 150,000 gate equivalents of digital logic that can be reconfigured by software. The general architecture and functionality of the MERCAL hardware and system software are described.

Self-Organization in Embedded Real-Time Systems

CERN Document Server

Brinkschulte, Uwe; Rettberg, Achim

2013-01-01

This book describes the emerging field of self-organizing, multicore, distributed and real-time embedded systems.  Self-organization of both hardware and software can be a key technique to handle the growing complexity of modern computing systems. Distributed systems running hundreds of tasks on dozens of processors, each equipped with multiple cores, requires self-organization principles to ensure efficient and reliable operation. This book addresses various, so-called Self-X features such as self-configuration, self-optimization, self-adaptation, self-healing and self-protection. Presents open components for embedded real-time adaptive and self-organizing applications; Describes innovative techniques in: scheduling, memory management, quality of service, communications supporting organic real-time applications; Covers multi-/many-core embedded systems supporting real-time adaptive systems and power-aware, adaptive hardware and software systems; Includes case studies of open embedded real-time self-organizi...

ADRC for spacecraft attitude and position synchronization in libration point orbits

Science.gov (United States)

Gao, Chen; Yuan, Jianping; Zhao, Yakun

2018-04-01

This paper addresses the problem of spacecraft attitude and position synchronization in libration point orbits between a leader and a follower. Using dual quaternion, the dimensionless relative coupled dynamical model is derived considering computation efficiency and accuracy. Then a model-independent dimensionless cascade pose-feedback active disturbance rejection controller is designed to spacecraft attitude and position tracking control problems considering parameter uncertainties and external disturbances. Numerical simulations for the final approach phase in spacecraft rendezvous and docking and formation flying are done, and the results show high-precision tracking errors and satisfactory convergent rates under bounded control torque and force which validate the proposed approach.

Autonomous spacecraft landing through human pre-attentive vision

International Nuclear Information System (INIS)

Schiavone, Giuseppina; Izzo, Dario; Simões, Luís F; De Croon, Guido C H E

2012-01-01

In this work, we exploit a computational model of human pre-attentive vision to guide the descent of a spacecraft on extraterrestrial bodies. Providing the spacecraft with high degrees of autonomy is a challenge for future space missions. Up to present, major effort in this research field has been concentrated in hazard avoidance algorithms and landmark detection, often by reference to a priori maps, ranked by scientists according to specific scientific criteria. Here, we present a bio-inspired approach based on the human ability to quickly select intrinsically salient targets in the visual scene; this ability is fundamental for fast decision-making processes in unpredictable and unknown circumstances. The proposed system integrates a simple model of the spacecraft and optimality principles which guarantee minimum fuel consumption during the landing procedure; detected salient sites are used for retargeting the spacecraft trajectory, under safety and reachability conditions. We compare the decisions taken by the proposed algorithm with that of a number of human subjects tested under the same conditions. Our results show how the developed algorithm is indistinguishable from the human subjects with respect to areas, occurrence and timing of the retargeting. (paper)

μShield : Configurable Code-Reuse Attacks Mitigation For Embedded Systems

NARCIS (Netherlands)

Abbasi, Ali; Wetzels, Jos; Bokslag, Wouter; Zambon, Emmanuele; Etalle, Sandro; Yan, Zheng; Molva, Refik; Mazurczyk, Wojciech; Kantola, Raimo

2017-01-01

Embedded devices are playing a major role in our way of life. Similar to other computer systems embedded devices are vulnerable to code-reuse attacks. Compromising these devices in a critical environment constitute a significant security and safety risk. In this paper, we present μShield, a memory

Automating a spacecraft electrical power system using expert systems

Science.gov (United States)

Lollar, L. F.

1991-01-01

Since Skylab, Marshall Space Flight Center (MSFC) has recognized the need for large electrical power systems (EPS's) in upcoming Spacecraft. The operation of the spacecraft depends on the EPS. Therefore, it must be efficient, safe, and reliable. In 1978, as a consequence of having to supply a large number of EPS personnel to monitor and control Skylab, the Electrical power Branch of MSFC began the autonomously managed power system (AMPS) project. This project resulted in the assembly of a 25-kW high-voltage dc test facility and provided the means of getting man out of the loop as much as possible. AMPS includes several embedded controllers which allow a significant level of autonomous operation. More recently, the Electrical Division at MSFC has developed the space station module power management and distribution (SSM/PMAD) breadboard to investigate managing and distributing power in the Space Station Freedom habitation and laboratory modules. Again, the requirement for a high level of autonomy for the efficient operation over the lifetime of the station and for the benefits of enhanced safety has been demonstrated. This paper describes the two breadboards and the hierarchical approach to automation which was developed through these projects.

Spacecraft Charging and the Microwave Anisotropy Probe Spacecraft

Science.gov (United States)

Timothy, VanSant J.; Neergaard, Linda F.

1998-01-01

The Microwave Anisotropy Probe (MAP), a MIDEX mission built in partnership between Princeton University and the NASA Goddard Space Flight Center (GSFC), will study the cosmic microwave background. It will be inserted into a highly elliptical earth orbit for several weeks and then use a lunar gravity assist to orbit around the second Lagrangian point (L2), 1.5 million kilometers, anti-sunward from the earth. The charging environment for the phasing loops and at L2 was evaluated. There is a limited set of data for L2; the GEOTAIL spacecraft measured relatively low spacecraft potentials (approx. 50 V maximum) near L2. The main area of concern for charging on the MAP spacecraft is the well-established threat posed by the "geosynchronous region" between 6-10 Re. The launch in the autumn of 2000 will coincide with the falling of the solar maximum, a period when the likelihood of a substorm is higher than usual. The likelihood of a substorm at that time has been roughly estimated to be on the order of 20% for a typical MAP mission profile. Because of the possibility of spacecraft charging, a requirement for conductive spacecraft surfaces was established early in the program. Subsequent NASCAP/GEO analyses for the MAP spacecraft demonstrated that a significant portion of the sunlit surface (solar cell cover glass and sunshade) could have nonconductive surfaces without significantly raising differential charging. The need for conductive materials on surfaces continually in eclipse has also been reinforced by NASCAP analyses.

Diverse Power Iteration Embeddings and Its Applications

Energy Technology Data Exchange (ETDEWEB)

Huang H.; Yoo S.; Yu, D.; Qin, H.

2014-12-14

Abstract—Spectral Embedding is one of the most effective dimension reduction algorithms in data mining. However, its computation complexity has to be mitigated in order to apply it for real-world large scale data analysis. Many researches have been focusing on developing approximate spectral embeddings which are more efficient, but meanwhile far less effective. This paper proposes Diverse Power Iteration Embeddings (DPIE), which not only retains the similar efficiency of power iteration methods but also produces a series of diverse and more effective embedding vectors. We test this novel method by applying it to various data mining applications (e.g. clustering, anomaly detection and feature selection) and evaluating their performance improvements. The experimental results show our proposed DPIE is more effective than popular spectral approximation methods, and obtains the similar quality of classic spectral embedding derived from eigen-decompositions. Moreover it is extremely fast on big data applications. For example in terms of clustering result, DPIE achieves as good as 95% of classic spectral clustering on the complex datasets but 4000+ times faster in limited memory environment.

On TTEthernet for Integrated Fault-Tolerant Spacecraft Networks

Science.gov (United States)

Loveless, Andrew

2015-01-01

There has recently been a push for adopting integrated modular avionics (IMA) principles in designing spacecraft architectures. This consolidation of multiple vehicle functions to shared computing platforms can significantly reduce spacecraft cost, weight, and de- sign complexity. Ethernet technology is attractive for inclusion in more integrated avionic systems due to its high speed, flexibility, and the availability of inexpensive commercial off-the-shelf (COTS) components. Furthermore, Ethernet can be augmented with a variety of quality of service (QoS) enhancements that enable its use for transmitting critical data. TTEthernet introduces a decentralized clock synchronization paradigm enabling the use of time-triggered Ethernet messaging appropriate for hard real-time applications. TTEthernet can also provide two forms of event-driven communication, therefore accommodating the full spectrum of traffic criticality levels required in IMA architectures. This paper explores the application of TTEthernet technology to future IMA spacecraft architectures as part of the Avionics and Software (A&S) project chartered by NASA's Advanced Exploration Systems (AES) program.

Research on spacecraft electrical power conversion

Science.gov (United States)

Wilson, T. G.

1983-01-01

The history of spacecraft electrical power conversion in literature, research and practice is reviewed. It is noted that the design techniques, analyses and understanding which were developed make today's contribution to power computers and communication installations. New applications which require more power, improved dynamic response, greater reliability, and lower cost are outlined. The switching mode approach in electronic power conditioning is discussed. Technical aspects of the research are summarized.

Pervasive Computing Support for Hospitals: An Overview of the Activity-Based Computing Project

DEFF Research Database (Denmark)

Christensen, Henrik Bærbak; Bardram, Jakob E

2007-01-01

The activity-based computing project researched pervasive computing support for clinical hospital work. Such technologies have potential for supporting the mobile, collaborative, and disruptive use of heterogeneous embedded devices in a hospital......The activity-based computing project researched pervasive computing support for clinical hospital work. Such technologies have potential for supporting the mobile, collaborative, and disruptive use of heterogeneous embedded devices in a hospital...

A real-time spike sorting method based on the embedded GPU.

Science.gov (United States)

Zelan Yang; Kedi Xu; Xiang Tian; Shaomin Zhang; Xiaoxiang Zheng

2017-07-01

Microelectrode arrays with hundreds of channels have been widely used to acquire neuron population signals in neuroscience studies. Online spike sorting is becoming one of the most important challenges for high-throughput neural signal acquisition systems. Graphic processing unit (GPU) with high parallel computing capability might provide an alternative solution for increasing real-time computational demands on spike sorting. This study reported a method of real-time spike sorting through computing unified device architecture (CUDA) which was implemented on an embedded GPU (NVIDIA JETSON Tegra K1, TK1). The sorting approach is based on the principal component analysis (PCA) and K-means. By analyzing the parallelism of each process, the method was further optimized in the thread memory model of GPU. Our results showed that the GPU-based classifier on TK1 is 37.92 times faster than the MATLAB-based classifier on PC while their accuracies were the same with each other. The high-performance computing features of embedded GPU demonstrated in our studies suggested that the embedded GPU provide a promising platform for the real-time neural signal processing.

SHARP: A multi-mission AI system for spacecraft telemetry monitoring and diagnosis

Science.gov (United States)

Lawson, Denise L.; James, Mark L.

1989-01-01

The Spacecraft Health Automated Reasoning Prototype (SHARP) is a system designed to demonstrate automated health and status analysis for multi-mission spacecraft and ground data systems operations. Telecommunications link analysis of the Voyager II spacecraft is the initial focus for the SHARP system demonstration which will occur during Voyager's encounter with the planet Neptune in August, 1989, in parallel with real-time Voyager operations. The SHARP system combines conventional computer science methodologies with artificial intelligence techniques to produce an effective method for detecting and analyzing potential spacecraft and ground systems problems. The system performs real-time analysis of spacecraft and other related telemetry, and is also capable of examining data in historical context. A brief introduction is given to the spacecraft and ground systems monitoring process at the Jet Propulsion Laboratory. The current method of operation for monitoring the Voyager Telecommunications subsystem is described, and the difficulties associated with the existing technology are highlighted. The approach taken in the SHARP system to overcome the current limitations is also described, as well as both the conventional and artificial intelligence solutions developed in SHARP.

Spacecraft Charge Monitor

Science.gov (United States)

Goembel, L.

2003-12-01

We are currently developing a flight prototype Spacecraft Charge Monitor (SCM) with support from NASA's Small Business Innovation Research (SBIR) program. The device will use a recently proposed high energy-resolution electron spectroscopic technique to determine spacecraft floating potential. The inspiration for the technique came from data collected by the Atmosphere Explorer (AE) satellites in the 1970s. The data available from the AE satellites indicate that the SCM may be able to determine spacecraft floating potential to within 0.1 V under certain conditions. Such accurate measurement of spacecraft charge could be used to correct biases in space plasma measurements. The device may also be able to measure spacecraft floating potential in the solar wind and in orbit around other planets.

Computer simulation of liquid cesium using embedded atom model

International Nuclear Information System (INIS)

Belashchenko, D K; Nikitin, N Yu

2008-01-01

The new method is presented for the inventing an embedded atom potential (EAM potential) for liquid metals. This method uses directly the pair correlation function (PCF) of the liquid metal near the melting temperature. Because of the specific analytic form of this EAM potential, the pair term of potential can be calculated using the pair correlation function and, for example, Schommers algorithm. Other parameters of EAM potential may be found using the potential energy, module of compression and pressure at some conditions, mainly near the melting temperature, at very high temperature or in strongly compressed state. We used the simple exponential formula for effective EAM electronic density and a polynomial series for embedding energy. Molecular dynamics method was applied with L. Verlet algorithm. A series of models with 1968 atoms in the basic cube was constructed in temperature interval 323-1923 K. The thermodynamic properties of liquid cesium, structure data and self-diffusion coefficients are calculated. In general, agreement between the model data and known experimental ones is reasonable. The evaluation is given for the critical temperature of cesium models with EAM potential

On Verification Modelling of Embedded Systems

NARCIS (Netherlands)

Brinksma, Hendrik; Mader, Angelika H.

Computer-aided verification of embedded systems hinges on the availability of good verification models of the systems at hand. Such models must be much simpler than full design models or specifications to be of practical value, because of the unavoidable combinatorial complexities in the

Generalized and Resource-Efficient VNet Embeddings with Migrations

OpenAIRE

Schaffrath, Gregor; Schmid, Stefan; Feldmann, Anja

2010-01-01

This paper attends to the problem of embedding flexibly specified CloudNets, virtual networks connecting cloud resources (such as storage or computation). We attend to a scenario where customers can request CloudNets at short notice, and an infrastructure provider (or a potential itermediate broker or reseller) first embeds the CloudNet fast (e.g., using a simple heuristic). Later, however, long-lived CloudNets embeddings are optimized by migrating them to more suitable locations, whose preci...

Application of square-root filtering for spacecraft attitude control

Science.gov (United States)

Sorensen, J. A.; Schmidt, S. F.; Goka, T.

1978-01-01

Suitable digital algorithms are developed and tested for providing on-board precision attitude estimation and pointing control for potential use in the Landsat-D spacecraft. These algorithms provide pointing accuracy of better than 0.01 deg. To obtain necessary precision with efficient software, a six state-variable square-root Kalman filter combines two star tracker measurements to update attitude estimates obtained from processing three gyro outputs. The validity of the estimation and control algorithms are established, and the sensitivity of their performance to various error sources and software parameters are investigated by detailed digital simulation. Spacecraft computer memory, cycle time, and accuracy requirements are estimated.

An Open Source Rapid Computer Aided Control System Design Toolchain Using Scilab, Scicos and RTAI Linux

Science.gov (United States)

Bouchpan-Lerust-Juéry, L.

2007-08-01

Current and next generation on-board computer systems tend to implement real-time embedded control applications (e.g. Attitude and Orbit Control Subsystem (AOCS), Packet Utililization Standard (PUS), spacecraft autonomy . . . ) which must meet high standards of Reliability and Predictability as well as Safety. All these requirements require a considerable amount of effort and cost for Space Sofware Industry. This paper, in a first part, presents a free Open Source integrated solution to develop RTAI applications from analysis, design, simulation and direct implementation using code generation based on Open Source and in its second part summarises this suggested approach, its results and the conclusion for further work.

SHARP: A multi-mission artificial intelligence system for spacecraft telemetry monitoring and diagnosis

Science.gov (United States)

Lawson, Denise L.; James, Mark L.

1989-01-01

The Spacecraft Health Automated Reasoning Prototype (SHARP) is a system designed to demonstrate automated health and status analysis for multi-mission spacecraft and ground data systems operations. Telecommunications link analysis of the Voyager 2 spacecraft is the initial focus for the SHARP system demonstration which will occur during Voyager's encounter with the planet Neptune in August, 1989, in parallel with real time Voyager operations. The SHARP system combines conventional computer science methodologies with artificial intelligence techniques to produce an effective method for detecting and analyzing potential spacecraft and ground systems problems. The system performs real time analysis of spacecraft and other related telemetry, and is also capable of examining data in historical context. A brief introduction is given to the spacecraft and ground systems monitoring process at the Jet Propulsion Laboratory. The current method of operation for monitoring the Voyager Telecommunications subsystem is described, and the difficulties associated with the existing technology are highlighted. The approach taken in the SHARP system to overcome the current limitations is also described, as well as both the conventional and artificial intelligence solutions developed in SHARP.

High-Fidelity Dynamic Modeling of Spacecraft in the Continuum--Rarefied Transition Regime

Science.gov (United States)

Turansky, Craig P.

The state of the art of spacecraft rarefied aerodynamics seldom accounts for detailed rigid-body dynamics. In part because of computational constraints, simpler models based upon the ballistic and drag coefficients are employed. Of particular interest is the continuum-rarefied transition regime of Earth's thermosphere where gas dynamic simulation is difficult yet wherein many spacecraft operate. The feasibility of increasing the fidelity of modeling spacecraft dynamics is explored by coupling rarefied aerodynamics with rigid-body dynamics modeling similar to that traditionally used for aircraft in atmospheric flight. Presented is a framework of analysis and guiding principles which capitalize on the availability of increasing computational methods and resources. Aerodynamic force inputs for modeling spacecraft in two dimensions in a rarefied flow are provided by analytical equations in the free-molecular regime, and the direct simulation Monte Carlo method in the transition regime. The application of the direct simulation Monte Carlo method to this class of problems is examined in detail with a new code specifically designed for engineering-level rarefied aerodynamic analysis. Time-accurate simulations of two distinct geometries in low thermospheric flight and atmospheric entry are performed, demonstrating non-linear dynamics that cannot be predicted using simpler approaches. The results of this straightforward approach to the aero-orbital coupled-field problem highlight the possibilities for future improvements in drag prediction, control system design, and atmospheric science. Furthermore, a number of challenges for future work are identified in the hope of stimulating the development of a new subfield of spacecraft dynamics.

The embedded operating system project

Science.gov (United States)

Campbell, R. H.

1984-01-01

This progress report describes research towards the design and construction of embedded operating systems for real-time advanced aerospace applications. The applications concerned require reliable operating system support that must accommodate networks of computers. The report addresses the problems of constructing such operating systems, the communications media, reconfiguration, consistency and recovery in a distributed system, and the issues of realtime processing. A discussion is included on suitable theoretical foundations for the use of atomic actions to support fault tolerance and data consistency in real-time object-based systems. In particular, this report addresses: atomic actions, fault tolerance, operating system structure, program development, reliability and availability, and networking issues. This document reports the status of various experiments designed and conducted to investigate embedded operating system design issues.

SPECT detector system design based on embedded system

International Nuclear Information System (INIS)

Zhang Weizheng; Zhao Shujun; Zhang Lei; Sun Yuanling

2007-01-01

A single-photon emission computed tomography detector system based on embedded Linux designed. This system is composed of detector module, data acquisition module, ARM MPU module, network interface communication module and human machine interface module. Its software uses multithreading technology based on embedded Linux. It can achieve high speed data acquisition, real-time data correction and network data communication. It can accelerate the data acquisition and decrease the dead time. The accuracy and the stability of the system can be improved. (authors)

Practical Applications of Cosmic Ray Science: Spacecraft, Aircraft, Ground Based Computation and Control Systems and Human Health and Safety

Science.gov (United States)

Atwell, William; Koontz, Steve; Normand, Eugene

2012-01-01

In this paper we review the discovery of cosmic ray effects on the performance and reliability of microelectronic systems as well as on human health and safety, as well as the development of the engineering and health science tools used to evaluate and mitigate cosmic ray effects in earth surface, atmospheric flight, and space flight environments. Three twentieth century technological developments, 1) high altitude commercial and military aircraft; 2) manned and unmanned spacecraft; and 3) increasingly complex and sensitive solid state micro-electronics systems, have driven an ongoing evolution of basic cosmic ray science into a set of practical engineering tools (e.g. ground based test methods as well as high energy particle transport and reaction codes) needed to design, test, and verify the safety and reliability of modern complex electronic systems as well as effects on human health and safety. The effects of primary cosmic ray particles, and secondary particle showers produced by nuclear reactions with spacecraft materials, can determine the design and verification processes (as well as the total dollar cost) for manned and unmanned spacecraft avionics systems. Similar considerations apply to commercial and military aircraft operating at high latitudes and altitudes near the atmospheric Pfotzer maximum. Even ground based computational and controls systems can be negatively affected by secondary particle showers at the Earth's surface, especially if the net target area of the sensitive electronic system components is large. Accumulation of both primary cosmic ray and secondary cosmic ray induced particle shower radiation dose is an important health and safety consideration for commercial or military air crews operating at high altitude/latitude and is also one of the most important factors presently limiting manned space flight operations beyond low-Earth orbit (LEO).

Embedded Leverage

DEFF Research Database (Denmark)

Frazzini, Andrea; Heje Pedersen, Lasse

find that asset classes with embedded leverage offer low risk-adjusted returns and, in the cross-section, higher embedded leverage is associated with lower returns. A portfolio which is long low-embedded-leverage securities and short high-embedded-leverage securities earns large abnormal returns...

Large Scale Experiments on Spacecraft Fire Safety

DEFF Research Database (Denmark)

Urban, David L.; Ruff, Gary A.; Minster, Olivier

2012-01-01

-based microgravity facilities or has been limited to very small fuel samples. Still, the work conducted to date has shown that fire behaviour in low-gravity is very different from that in normal-gravity, with differences observed for flammability limits, ignition delay, flame spread behaviour, flame colour and flame......Full scale fire testing complemented by computer modelling has provided significant knowhow about the risk, prevention and suppression of fire in terrestrial systems (cars, ships, planes, buildings, mines, and tunnels). In comparison, no such testing has been carried out for manned spacecraft due...... to the complexity, cost and risk associ-ated with operating a long duration fire safety experiment of a relevant size in microgravity. Therefore, there is currently a gap in knowledge of fire behaviour in spacecraft. The entire body of low-gravity fire research has either been conducted in short duration ground...

Reconfiguration of Computation and Communication Resources in Multi-Core Real-Time Embedded Systems

DEFF Research Database (Denmark)

Pezzarossa, Luca

-core platform. Our approach is to associate reconfiguration with operational mode changes where the system, during normal operation, changes a subset of the executing tasks to adapt its behaviour to new conditions. Reconfiguration is therefore used during a mode change to modify the real-time guaranteed services...... of the communication channels between the tasks that are affected by the reconfiguration. This thesis investigates the use of reconfiguration in the context of multicore realtime systems targeting embedded applications. We address the reconfiguration of both the computation and the communication resources of a multi...... by the communication fabric between the cores of the platform. To support this, we present a new network on chip architecture, named Argo 2, that allows instantaneous and time-predictable reconfiguration of the communication channels. Our reconfiguration-capable architecture is prototyped using the existing time...

Optimal Electrical Energy Slewing for Reaction Wheel Spacecraft

Science.gov (United States)

Marsh, Harleigh Christian

The results contained in this dissertation contribute to a deeper level of understanding to the energy required to slew a spacecraft using reaction wheels. This work addresses the fundamental manner in which spacecrafts are slewed (eigenaxis maneuvering), and demonstrates that this conventional maneuver can be dramatically improved upon in regards to reduction of energy, dissipative losses, as well as peak power. Energy is a fundamental resource that effects every asset, system, and subsystem upon a spacecraft, from the attitude control system which orients the spacecraft, to the communication subsystem to link with ground stations, to the payloads which collect scientific data. For a reaction wheel spacecraft, the attitude control system is a particularly heavy load on the power and energy resources on a spacecraft. The central focus of this dissertation is reducing the burden which the attitude control system places upon the spacecraft in regards to electrical energy, which is shown in this dissertation to be a challenging problem to computationally solve and analyze. Reducing power and energy demands can have a multitude of benefits, spanning from the initial design phase, to in-flight operations, to potentially extending the mission life of the spacecraft. This goal is approached from a practical standpoint apropos to an industry-flight setting. Metrics to measure electrical energy and power are developed which are in-line with the cost associated to operating reaction wheel based attitude control systems. These metrics are incorporated into multiple families of practical high-dimensional constrained nonlinear optimal control problems to reduce the electrical energy, as well as the instantaneous power burdens imposed by the attitude control system upon the spacecraft. Minimizing electrical energy is shown to be a problem in L1 optimal control which is nonsmooth in regards to state variables as well as the control. To overcome the challenge of nonsmoothness, a

Model predictive control for spacecraft rendezvous in elliptical orbit

Science.gov (United States)

Li, Peng; Zhu, Zheng H.

2018-05-01

This paper studies the control of spacecraft rendezvous with attitude stable or spinning targets in an elliptical orbit. The linearized Tschauner-Hempel equation is used to describe the motion of spacecraft and the problem is formulated by model predictive control. The control objective is to maximize control accuracy and smoothness simultaneously to avoid unexpected change or overshoot of trajectory for safe rendezvous. It is achieved by minimizing the weighted summations of control errors and increments. The effects of two sets of horizons (control and predictive horizons) in the model predictive control are examined in terms of fuel consumption, rendezvous time and computational effort. The numerical results show the proposed control strategy is effective.

Data management in the mission data system

Science.gov (United States)

Wagner, David A.

2005-01-01

As spacecraft evolve from simple embedded devices to become more sophisticated computing platforms with complex behaviors it is increasingly necessary to model and manage the flow of data, and to provide uniform models for managing data that promote adaptability, yet pay heed to the physical limitations of the embedded and space environments.

Link Analysis of High Throughput Spacecraft Communication Systems for Future Science Missions

Science.gov (United States)

Simons, Rainee N.

2015-01-01

NASA's plan to launch several spacecrafts into low Earth Orbit (LEO) to support science missions in the next ten years and beyond requires down link throughput on the order of several terabits per day. The ability to handle such a large volume of data far exceeds the capabilities of current systems. This paper proposes two solutions, first, a high data rate link between the LEO spacecraft and ground via relay satellites in geostationary orbit (GEO). Second, a high data rate direct to ground link from LEO. Next, the paper presents results from computer simulations carried out for both types of links taking into consideration spacecraft transmitter frequency, EIRP, and waveform; elevation angle dependent path loss through Earths atmosphere, and ground station receiver GT.

Implementation of an Embedded Web Server Application for Wireless Control of Brain Computer Interface Based Home Environments.

Science.gov (United States)

Aydın, Eda Akman; Bay, Ömer Faruk; Güler, İnan

2016-01-01

Brain Computer Interface (BCI) based environment control systems could facilitate life of people with neuromuscular diseases, reduces dependence on their caregivers, and improves their quality of life. As well as easy usage, low-cost, and robust system performance, mobility is an important functionality expected from a practical BCI system in real life. In this study, in order to enhance users' mobility, we propose internet based wireless communication between BCI system and home environment. We designed and implemented a prototype of an embedded low-cost, low power, easy to use web server which is employed in internet based wireless control of a BCI based home environment. The embedded web server provides remote access to the environmental control module through BCI and web interfaces. While the proposed system offers to BCI users enhanced mobility, it also provides remote control of the home environment by caregivers as well as the individuals in initial stages of neuromuscular disease. The input of BCI system is P300 potentials. We used Region Based Paradigm (RBP) as stimulus interface. Performance of the BCI system is evaluated on data recorded from 8 non-disabled subjects. The experimental results indicate that the proposed web server enables internet based wireless control of electrical home appliances successfully through BCIs.

Protection of surface assets on Mars from wind blown jettisoned spacecraft components

Science.gov (United States)

Paton, Mark

2017-07-01

Jettisoned Entry, Descent and Landing System (EDLS) hardware from landing spacecraft have been observed by orbiting spacecraft, strewn over the Martian surface. Future Mars missions that land spacecraft close to prelanded assets will have to use a landing architecture that somehow minimises the possibility of impacts from these jettisoned EDLS components. Computer modelling is used here to investigate the influence of wind speed and direction on the distribution of EDLS components on the surface. Typical wind speeds encountered in the Martian Planetary Boundary Layer (PBL) were found to be of sufficient strength to blow items having a low ballistic coefficient, i.e. Hypersonic Inflatable Aerodynamic Decelerators (HIADs) or parachutes, onto prelanded assets even when the lander itself touches down several kilometres away. Employing meteorological measurements and careful characterisation of the Martian PBL, e.g. appropriate wind speed probability density functions, may then benefit future spacecraft landings, increase safety and possibly help reduce the delta v budget for Mars landers that rely on aerodynamic decelerators.

Adaptive GDDA-BLAST: fast and efficient algorithm for protein sequence embedding.

Directory of Open Access Journals (Sweden)

Yoojin Hong

2010-10-01

Full Text Available A major computational challenge in the genomic era is annotating structure/function to the vast quantities of sequence information that is now available. This problem is illustrated by the fact that most proteins lack comprehensive annotations, even when experimental evidence exists. We previously theorized that embedded-alignment profiles (simply "alignment profiles" hereafter provide a quantitative method that is capable of relating the structural and functional properties of proteins, as well as their evolutionary relationships. A key feature of alignment profiles lies in the interoperability of data format (e.g., alignment information, physio-chemical information, genomic information, etc.. Indeed, we have demonstrated that the Position Specific Scoring Matrices (PSSMs are an informative M-dimension that is scored by quantitatively measuring the embedded or unmodified sequence alignments. Moreover, the information obtained from these alignments is informative, and remains so even in the "twilight zone" of sequence similarity (<25% identity. Although our previous embedding strategy was powerful, it suffered from contaminating alignments (embedded AND unmodified and high computational costs. Herein, we describe the logic and algorithmic process for a heuristic embedding strategy named "Adaptive GDDA-BLAST." Adaptive GDDA-BLAST is, on average, up to 19 times faster than, but has similar sensitivity to our previous method. Further, data are provided to demonstrate the benefits of embedded-alignment measurements in terms of detecting structural homology in highly divergent protein sequences and isolating secondary structural elements of transmembrane and ankyrin-repeat domains. Together, these advances allow further exploration of the embedded alignment data space within sufficiently large data sets to eventually induce relevant statistical inferences. We show that sequence embedding could serve as one of the vehicles for measurement of low

Integrated Design Tools for Embedded Control Systems

NARCIS (Netherlands)

Jovanovic, D.S.; Hilderink, G.H.; Broenink, Johannes F.; Karelse, F.

2001-01-01

Currently, computer-based control systems are still being implemented using the same techniques as 10 years ago. The purpose of this project is the development of a design framework, consisting of tools and libraries, which allows the designer to build high reliable heterogeneous real-time embedded

Co Modeling and Co Synthesis of Safety Critical Multi threaded Embedded Software for Multi Core Embedded Platforms

Science.gov (United States)

2017-03-20

Kaiserslautern Kaiserslautern, Germany Sandeep Shukla FERMAT Lab Electrical and Computer Engineering Department Virginia Tech 900 North Glebe Road...Software Engineering , Software Producibility, Component-based software design, behavioral types, behavioral type inference, Polychronous model of...near future, many embedded applications including safety critical ones as used in avionics, automotive , mission control systems will run on

Modeling Electronic Circular Dichroism within the Polarizable Embedding Approach

DEFF Research Database (Denmark)

Nørby, Morten S; Olsen, Jógvan Magnus Haugaard; Steinmann, Casper

2017-01-01

We present a systematic investigation of the key components needed to model single chromophore electronic circular dichroism (ECD) within the polarizable embedding (PE) approach. By relying on accurate forms of the embedding potential, where especially the inclusion of local field effects...... are in focus, we show that qualitative agreement between rotatory strength parameters calculated by full quantum mechanical calculations and the more efficient embedding calculations can be obtained. An important aspect in the computation of reliable absorption parameters is the need for conformational...... sampling. We show that a significant number of snapshots are needed to avoid artifacts in the calculated electronic circular dichroism parameters due to insufficient configurational sampling, thus highlighting the efficiency of the PE model....

Compact Acoustic Models for Embedded Speech Recognition

Directory of Open Access Journals (Sweden)

Lévy Christophe

2009-01-01

Full Text Available Speech recognition applications are known to require a significant amount of resources. However, embedded speech recognition only authorizes few KB of memory, few MIPS, and small amount of training data. In order to fit the resource constraints of embedded applications, an approach based on a semicontinuous HMM system using state-independent acoustic modelling is proposed. A transformation is computed and applied to the global model in order to obtain each HMM state-dependent probability density functions, authorizing to store only the transformation parameters. This approach is evaluated on two tasks: digit and voice-command recognition. A fast adaptation technique of acoustic models is also proposed. In order to significantly reduce computational costs, the adaptation is performed only on the global model (using related speaker recognition adaptation techniques with no need for state-dependent data. The whole approach results in a relative gain of more than 20% compared to a basic HMM-based system fitting the constraints.

TTEthernet for Integrated Spacecraft Networks

Science.gov (United States)

Loveless, Andrew

2015-01-01

Aerospace projects have traditionally employed federated avionics architectures, in which each computer system is designed to perform one specific function (e.g. navigation). There are obvious downsides to this approach, including excessive weight (from so much computing hardware), and inefficient processor utilization (since modern processors are capable of performing multiple tasks). There has therefore been a push for integrated modular avionics (IMA), in which common computing platforms can be leveraged for different purposes. This consolidation of multiple vehicle functions to shared computing platforms can significantly reduce spacecraft cost, weight, and design complexity. However, the application of IMA principles introduces significant challenges, as the data network must accommodate traffic of mixed criticality and performance levels - potentially all related to the same shared computer hardware. Because individual network technologies are rarely so competent, the development of truly integrated network architectures often proves unreasonable. Several different types of networks are utilized - each suited to support a specific vehicle function. Critical functions are typically driven by precise timing loops, requiring networks with strict guarantees regarding message latency (i.e. determinism) and fault-tolerance. Alternatively, non-critical systems generally employ data networks prioritizing flexibility and high performance over reliable operation. Switched Ethernet has seen widespread success filling this role in terrestrial applications. Its high speed, flexibility, and the availability of inexpensive commercial off-the-shelf (COTS) components make it desirable for inclusion in spacecraft platforms. Basic Ethernet configurations have been incorporated into several preexisting aerospace projects, including both the Space Shuttle and International Space Station (ISS). However, classical switched Ethernet cannot provide the high level of network

Using embedded computer-assisted instruction to teach science to students with Autism Spectrum Disorders

Science.gov (United States)

Smith, Bethany

The need for promoting scientific literacy for all students has been the focus of recent education reform resulting in the rise of the Science Technology, Engineering, and Mathematics movement. For students with Autism Spectrum Disorders and intellectual disability, this need for scientific literacy is further complicated by the need for individualized instruction that is often required to teach new skills, especially when those skills are academic in nature. In order to address this need for specialized instruction, as well as scientific literacy, this study investigated the effects of embedded computer-assisted instruction to teach science terms and application of those terms to three middle school students with autism and intellectual disability. This study was implemented within an inclusive science classroom setting. A multiple probe across participants research design was used to examine the effectiveness of the intervention. Results of this study showed a functional relationship between the number of correct responses made during probe sessions and introduction of the intervention. Additionally, all three participants maintained the acquired science terms and applications over time and generalized these skills across materials and settings. The findings of this study suggest several implications for practice within inclusive settings and provide suggestions for future research investigating the effectiveness of computer-assisted instruction to teach academic skills to students with Autism Spectrum Disorders and intellectual disability.

TINY TCP/IP PROTOCOL SUITE FOR EMBEDDED SYSTEMS WITH 32 BIT MICROCONTROLLER

OpenAIRE

Mr. Praful M. Godhankar; Mr. Maske Vishnu Dattatraya; Prof. Shahzia Sayyad

2015-01-01

The scope of embedded devices is increasing day by day and the demand will be further more when networking technology is incorporated into these devices. Many embedded systems not only communicate with each other, but also with computers using a network. All systems connected to the Internet, wireless networks such as WLAN and GPRS, and many local area networks communicate using the standard TCP/IP protocol suite. An embedded system may have as little memory, the memory constraints make progr...

Like the breathability of air: Embodied embedded communication

NARCIS (Netherlands)

Haselager, W.F.G.

2012-01-01

I present experimental and computational research, inspired by the perspective of Embodied Embedded Cognition, concerning various aspects of language as supporting Everett’s interactionist view of language. Based on earlier and ongoing work, I briefly illustrate the contribution of the environment

Conceptualizing Embedded Configuration

DEFF Research Database (Denmark)

Oddsson, Gudmundur Valur; Hvam, Lars; Lysgaard, Ole

2006-01-01

and services. The general idea can be named embedded configuration. In this article we intend to conceptualize embedded configuration, what it is and is not. The difference between embedded configuration, sales configuration and embedded software is explained. We will look at what is needed to make embedded...... configuration systems. That will include requirements to product modelling techniques. An example with consumer electronics will illuminate the elements of embedded configuration in settings that most can relate to. The question of where embedded configuration would be relevant is discussed, and the current...

Rapid Calculation of Spacecraft Trajectories Using Efficient Taylor Series Integration

Science.gov (United States)

Scott, James R.; Martini, Michael C.

2011-01-01

A variable-order, variable-step Taylor series integration algorithm was implemented in NASA Glenn's SNAP (Spacecraft N-body Analysis Program) code. SNAP is a high-fidelity trajectory propagation program that can propagate the trajectory of a spacecraft about virtually any body in the solar system. The Taylor series algorithm's very high order accuracy and excellent stability properties lead to large reductions in computer time relative to the code's existing 8th order Runge-Kutta scheme. Head-to-head comparison on near-Earth, lunar, Mars, and Europa missions showed that Taylor series integration is 15.8 times faster than Runge- Kutta on average, and is more accurate. These speedups were obtained for calculations involving central body, other body, thrust, and drag forces. Similar speedups have been obtained for calculations that include J2 spherical harmonic for central body gravitation. The algorithm includes a step size selection method that directly calculates the step size and never requires a repeat step. High-order Taylor series integration algorithms have been shown to provide major reductions in computer time over conventional integration methods in numerous scientific applications. The objective here was to directly implement Taylor series integration in an existing trajectory analysis code and demonstrate that large reductions in computer time (order of magnitude) could be achieved while simultaneously maintaining high accuracy. This software greatly accelerates the calculation of spacecraft trajectories. At each time level, the spacecraft position, velocity, and mass are expanded in a high-order Taylor series whose coefficients are obtained through efficient differentiation arithmetic. This makes it possible to take very large time steps at minimal cost, resulting in large savings in computer time. The Taylor series algorithm is implemented primarily through three subroutines: (1) a driver routine that automatically introduces auxiliary variables and

Corrosion Monitors for Embedded Evaluation

Energy Technology Data Exchange (ETDEWEB)

Robinson, Alex L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Pfeifer, Kent B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Casias, Adrian L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Howell, Stephen W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sorensen, Neil R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Missert, Nancy A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2017-05-01

We have developed and characterized novel in-situ corrosion sensors to monitor and quantify the corrosive potential and history of localized environments. Embedded corrosion sensors can provide information to aid health assessments of internal electrical components including connectors, microelectronics, wires, and other susceptible parts. When combined with other data (e.g. temperature and humidity), theory, and computational simulation, the reliability of monitored systems can be predicted with higher fidelity.

New approach to invariant-embedding methods in reactor physics calculations

International Nuclear Information System (INIS)

Forsbacka, M.J.; Rydin, R.A.

1997-01-01

Invariant-embedding methods offer an alternative approach to modeling physical phenomena and solving mathematical problems. Invariant embedding allows one to express traditional boundary-value problems as initial-value problems. In doing this, one effectively reformulates a problem to be solved in terms of an embedding parameter. In this paper, a hybrid method that consists of Monte Carlo-generated response functions that describe the neutronic properties of local spatial cells are coupled together in a global reactor model using the invariant embedding methodology, where the system multiplication factor k eff is used as the embedding parameter. Thus, k eff is computed directly rather than as the result of a secondary eigenvalue calculation. Because the response functions can represent any arbitrary material distribution within a local cell, this method shows promise to accurately assess the change in reactivity due to core disruptive accidents and other changes in system configuration such as changing control rod positions. This paper reports a series of proof-of-concept calculations that assess this method

Embedded Control in Wearable Medical Devices: Application to the Artificial Pancreas

Directory of Open Access Journals (Sweden)

Stamatina Zavitsanou

2016-09-01

Full Text Available Significant increases in processing power, coupled with the miniaturization of processing units operating at low power levels, has motivated the embedding of modern control systems into medical devices. The design of such embedded decision-making strategies for medical applications is driven by multiple crucial factors, such as: (i guaranteed safety in the presence of exogenous disturbances and unexpected system failures; (ii constraints on computing resources; (iii portability and longevity in terms of size and power consumption; and (iv constraints on manufacturing and maintenance costs. Embedded control systems are especially compelling in the context of modern artificial pancreas systems (AP used in glucose regulation for patients with type 1 diabetes mellitus (T1DM. Herein, a review of potential embedded control strategies that can be leveraged in a fully-automated and portable AP is presented. Amongst competing controllers, emphasis is provided on model predictive control (MPC, since it has been established as a very promising control strategy for glucose regulation using the AP. Challenges involved in the design, implementation and validation of safety-critical embedded model predictive controllers for the AP application are discussed in detail. Additionally, the computational expenditure inherent to MPC strategies is investigated, and a comparative study of runtime performances and storage requirements among modern quadratic programming solvers is reported for a desktop environment and a prototype hardware platform.

Automatic generation of co-embeddings from relational data with adaptive shaping.

Science.gov (United States)

Mu, Tingting; Goulermas, John Yannis

2013-10-01

In this paper, we study the co-embedding problem of how to map different types of patterns into one common low-dimensional space, given only the associations (relation values) between samples. We conduct a generic analysis to discover the commonalities between existing co-embedding algorithms and indirectly related approaches and investigate possible factors controlling the shapes and distributions of the co-embeddings. The primary contribution of this work is a novel method for computing co-embeddings, termed the automatic co-embedding with adaptive shaping (ACAS) algorithm, based on an efficient transformation of the co-embedding problem. Its advantages include flexible model adaptation to the given data, an economical set of model variables leading to a parametric co-embedding formulation, and a robust model fitting criterion for model optimization based on a quantization procedure. The secondary contribution of this work is the introduction of a set of generic schemes for the qualitative analysis and quantitative assessment of the output of co-embedding algorithms, using existing labeled benchmark datasets. Experiments with synthetic and real-world datasets show that the proposed algorithm is very competitive compared to existing ones.

Programs To Optimize Spacecraft And Aircraft Trajectories

Science.gov (United States)

Brauer, G. L.; Petersen, F. M.; Cornick, D.E.; Stevenson, R.; Olson, D. W.

1994-01-01

POST/6D POST is set of two computer programs providing ability to target and optimize trajectories of powered or unpowered spacecraft or aircraft operating at or near rotating planet. POST treats point-mass, three-degree-of-freedom case. 6D POST treats more-general rigid-body, six-degree-of-freedom (with point masses) case. Used to solve variety of performance, guidance, and flight-control problems for atmospheric and orbital vehicles. Applications include computation of performance or capability of vehicle in ascent, or orbit, and during entry into atmosphere, simulation and analysis of guidance and flight-control systems, dispersion-type analyses and analyses of loads, general-purpose six-degree-of-freedom simulation of controlled and uncontrolled vehicles, and validation of performance in six degrees of freedom. Written in FORTRAN 77 and C language. Two machine versions available: one for SUN-series computers running SunOS(TM) (LAR-14871) and one for Silicon Graphics IRIS computers running IRIX(TM) operating system (LAR-14869).

Hardware for soft computing and soft computing for hardware

CERN Document Server

Nedjah, Nadia

2014-01-01

Single and Multi-Objective Evolutionary Computation (MOEA),  Genetic Algorithms (GAs), Artificial Neural Networks (ANNs), Fuzzy Controllers (FCs), Particle Swarm Optimization (PSO) and Ant colony Optimization (ACO) are becoming omnipresent in almost every intelligent system design. Unfortunately, the application of the majority of these techniques is complex and so requires a huge computational effort to yield useful and practical results. Therefore, dedicated hardware for evolutionary, neural and fuzzy computation is a key issue for designers. With the spread of reconfigurable hardware such as FPGAs, digital as well as analog hardware implementations of such computation become cost-effective. The idea behind this book is to offer a variety of hardware designs for soft computing techniques that can be embedded in any final product. Also, to introduce the successful application of soft computing technique to solve many hard problem encountered during the design of embedded hardware designs. Reconfigurable em...

Toward real-time virtual biopsy of oral lesions using confocal laser endomicroscopy interfaced with embedded computing.

Science.gov (United States)

Thong, Patricia S P; Tandjung, Stephanus S; Movania, Muhammad Mobeen; Chiew, Wei-Ming; Olivo, Malini; Bhuvaneswari, Ramaswamy; Seah, Hock-Soon; Lin, Feng; Qian, Kemao; Soo, Khee-Chee

2012-05-01

Oral lesions are conventionally diagnosed using white light endoscopy and histopathology. This can pose a challenge because the lesions may be difficult to visualise under white light illumination. Confocal laser endomicroscopy can be used for confocal fluorescence imaging of surface and subsurface cellular and tissue structures. To move toward real-time "virtual" biopsy of oral lesions, we interfaced an embedded computing system to a confocal laser endomicroscope to achieve a prototype three-dimensional (3-D) fluorescence imaging system. A field-programmable gated array computing platform was programmed to enable synchronization of cross-sectional image grabbing and Z-depth scanning, automate the acquisition of confocal image stacks and perform volume rendering. Fluorescence imaging of the human and murine oral cavities was carried out using the fluorescent dyes fluorescein sodium and hypericin. Volume rendering of cellular and tissue structures from the oral cavity demonstrate the potential of the system for 3-D fluorescence visualization of the oral cavity in real-time. We aim toward achieving a real-time virtual biopsy technique that can complement current diagnostic techniques and aid in targeted biopsy for better clinical outcomes.

Effect of External Disturbing Gravity Field on Spacecraft Guidance and Surveying Line Layout for Marine Gravity Survey

Directory of Open Access Journals (Sweden)

HUANG Motao

2016-11-01

Full Text Available Centred on the support requirement of flying track control for a long range spacecraft, a detail research is made on the computation of external disturbing gravity field, the survey accuracy of gravity anomaly on the earth' surface and the program of surveying line layout for marine gravity survey. Firstly, the solution expression of navigation error for a long range spacecraft is analyzed and modified, and the influence of the earth's gravity field on flying track of spacecraft is evaluated. Then with a given limited quota of biased error of spacecraft drop point, the accuracy requirement for calculating the external disturbing gravity field is discussed and researched. Secondly, the data truncation error and the propagated data error are studied and estimated, and the quotas of survey resolution and computation accuracy for gravity anomaly on the earth' surface are determined. Finally, based on the above quotas, a corresponding program of surveying line layout for marine gravity survey is proposed. A numerical test has been made to prove the reasonableness and validity of the suggested program.

Short rendezvous missions for advanced Russian human spacecraft

Science.gov (United States)

Murtazin, Rafail F.; Budylov, Sergey G.

2010-10-01

The two-day stay of crew in a limited inhabited volume of the Soyuz-TMA spacecraft till docking to ISS is one of the most stressful parts of space flight. In this paper a number of possible ways to reduce the duration of the free flight phase are considered. The duration is defined by phasing strategy that is necessary for reduction of the phase angle between the chaser and target spacecraft. Some short phasing strategies could be developed. The use of such strategies creates more comfortable flight conditions for crew thanks to short duration and additionally it allows saving spacecraft's life support resources. The transition from the methods of direct spacecraft rendezvous using one orbit phasing (first flights of " Vostok" and " Soyuz" vehicles) to the currently used methods of two-day rendezvous mission can be observed in the history of Soviet manned space program. For an advanced Russian human rated spacecraft the short phasing strategy is recommended, which can be considered as a combination between the direct and two-day rendezvous missions. The following state of the art technologies are assumed available: onboard accurate navigation; onboard computations of phasing maneuvers; launch vehicle with high accuracy injection orbit, etc. Some operational requirements and constraints for the strategies are briefly discussed. In order to provide acceptable phase angles for possible launch dates the experience of the ISS altitude profile control can be used. As examples of the short phasing strategies, the following rendezvous missions are considered: direct ascent, short mission with the phasing during 3-7 orbits depending on the launch date (nominal or backup). For each option statistical modeling of the rendezvous mission is fulfilled, as well as an admissible phase angle range, accuracy of target state vector and addition fuel consumption coming out of emergency is defined. In this paper an estimation of pros and cons of all options is conducted.

Unsteady Flame Embedding

KAUST Repository

El-Asrag, Hossam A.

2011-01-01

Direct simulation of all the length and time scales relevant to practical combustion processes is computationally prohibitive. When combustion processes are driven by reaction and transport phenomena occurring at the unresolved scales of a numerical simulation, one must introduce a dynamic subgrid model that accounts for the multiscale nature of the problem using information available on a resolvable grid. Here, we discuss a model that captures unsteady flow-flame interactions- including extinction, re-ignition, and history effects-via embedded simulations at the subgrid level. The model efficiently accounts for subgrid flame structure and incorporates detailed chemistry and transport, allowing more accurate prediction of the stretch effect and the heat release. In this chapter we first review the work done in the past thirty years to develop the flame embedding concept. Next we present a formulation for the same concept that is compatible with Large Eddy Simulation in the flamelet regimes. The unsteady flame embedding approach (UFE) treats the flame as an ensemble of locally one-dimensional flames, similar to the flamelet approach. However, a set of elemental one-dimensional flames is used to describe the turbulent flame structure directly at the subgrid level. The calculations employ a one-dimensional unsteady flame model that incorporates unsteady strain rate, curvature, and mixture boundary conditions imposed by the resolved scales. The model is used for closure of the subgrid terms in the context of large eddy simulation. Direct numerical simulation (DNS) data from a flame-vortex interaction problem is used for comparison. © Springer Science+Business Media B.V. 2011.

Modeling and optimization of parallel and distributed embedded systems

CERN Document Server

Munir, Arslan; Ranka, Sanjay

2016-01-01

This book introduces the state-of-the-art in research in parallel and distributed embedded systems, which have been enabled by developments in silicon technology, micro-electro-mechanical systems (MEMS), wireless communications, computer networking, and digital electronics. These systems have diverse applications in domains including military and defense, medical, automotive, and unmanned autonomous vehicles. The emphasis of the book is on the modeling and optimization of emerging parallel and distributed embedded systems in relation to the three key design metrics of performance, power and dependability.

[Design of an embedded stroke rehabilitation apparatus system based on Linux computer engineering].

Science.gov (United States)

Zhuang, Pengfei; Tian, XueLong; Zhu, Lin

2014-04-01

A realizaton project of electrical stimulator aimed at motor dysfunction of stroke is proposed in this paper. Based on neurophysiological biofeedback, this system, using an ARM9 S3C2440 as the core processor, integrates collection and display of surface electromyography (sEMG) signal, as well as neuromuscular electrical stimulation (NMES) into one system. By embedding Linux system, the project is able to use Qt/Embedded as a graphical interface design tool to accomplish the design of stroke rehabilitation apparatus. Experiments showed that this system worked well.

The scheduling of tracking times for interplanetary spacecraft on the Deep Space Network

Science.gov (United States)

Webb, W. A.

1978-01-01

The Deep Space Network (DSN) is a network of tracking stations, located throughout the globe, used to track spacecraft for NASA's interplanetary missions. This paper describes a computer program, DSNTRAK, which provides an optimum daily tracking schedule for the DSN given the view periods at each station for a mission set of n spacecraft, where n is between 2 and 6. The objective function is specified in terms of relative total daily tracking time requirements between the n spacecraft. Linear programming is used to maximize the total daily tracking time and determine an optimal daily tracking schedule consistent with DSN station capabilities. DSNTRAK is used as part of a procedure to provide DSN load forecasting information for proposed future NASA mission sets.

Research on Face Recognition Based on Embedded System

Directory of Open Access Journals (Sweden)

Hong Zhao

2013-01-01

Full Text Available Because a number of image feature data to store, complex calculation to execute during the face recognition, therefore the face recognition process was realized only by PCs with high performance. In this paper, the OpenCV facial Haar-like features were used to identify face region; the Principal Component Analysis (PCA was employed in quick extraction of face features and the Euclidean Distance was also adopted in face recognition; as thus, data amount and computational complexity would be reduced effectively in face recognition, and the face recognition could be carried out on embedded platform. Finally, based on Tiny6410 embedded platform, a set of embedded face recognition systems was constructed. The test results showed that the system has stable operation and high recognition rate can be used in portable and mobile identification and authentication.

A real-time photogrammetry system based on embedded architecture

Directory of Open Access Journals (Sweden)

S. Y. Zheng

2014-06-01

Full Text Available In order to meet the demand of real-time spatial data processing and improve the online processing capability of photogrammetric system, a kind of real-time photogrammetry method is proposed in this paper. According to the proposed method, system based on embedded architecture is then designed: using FPGA, ARM+DSP and other embedded computing technology to build specialized hardware operating environment, transplanting and optimizing the existing photogrammetric algorithm to the embedded system, and finally real-time photogrammetric data processing is realized. At last, aerial photogrammetric experiment shows that the method can achieve high-speed and stable on-line processing of photogrammetric data. And the experiment also verifies the feasibility of the proposed real-time photogrammetric system based on embedded architecture. It is the first time to realize real-time aerial photogrammetric system, which can improve the online processing efficiency of photogrammetry to a higher level and broaden the application field of photogrammetry.

Adaptive Probabilistic Tracking Embedded in Smart Cameras for Distributed Surveillance in a 3D Model

Directory of Open Access Journals (Sweden)

Sven Fleck

2006-12-01

Full Text Available Tracking applications based on distributed and embedded sensor networks are emerging today, both in the fields of surveillance and industrial vision. Traditional centralized approaches have several drawbacks, due to limited communication bandwidth, computational requirements, and thus limited spatial camera resolution and frame rate. In this article, we present network-enabled smart cameras for probabilistic tracking. They are capable of tracking objects adaptively in real time and offer a very bandwidthconservative approach, as the whole computation is performed embedded in each smart camera and only the tracking results are transmitted, which are on a higher level of abstraction. Based on this, we present a distributed surveillance system. The smart cameras' tracking results are embedded in an integrated 3D environment as live textures and can be viewed from arbitrary perspectives. Also a georeferenced live visualization embedded in Google Earth is presented.

Adaptive Probabilistic Tracking Embedded in Smart Cameras for Distributed Surveillance in a 3D Model

Directory of Open Access Journals (Sweden)

Fleck Sven

2007-01-01

Full Text Available Tracking applications based on distributed and embedded sensor networks are emerging today, both in the fields of surveillance and industrial vision. Traditional centralized approaches have several drawbacks, due to limited communication bandwidth, computational requirements, and thus limited spatial camera resolution and frame rate. In this article, we present network-enabled smart cameras for probabilistic tracking. They are capable of tracking objects adaptively in real time and offer a very bandwidthconservative approach, as the whole computation is performed embedded in each smart camera and only the tracking results are transmitted, which are on a higher level of abstraction. Based on this, we present a distributed surveillance system. The smart cameras' tracking results are embedded in an integrated 3D environment as live textures and can be viewed from arbitrary perspectives. Also a georeferenced live visualization embedded in Google Earth is presented.

Rapid Open Source GPS software development for modern embedded systems:using the GPSTk with the Gumstix

OpenAIRE

Salazar Hernández, Dagoberto José; Hernández Pajares, Manuel; Juan Zornoza, José Miguel; Sanz Subirana, Jaume

2006-01-01

This work shows how the combination of GPS Open Source Software (GOSS) and advanced full function miniature computers (FFMC) allows rapid development, implementation and testing of advanced embedded GNSS data processing applications in a flexible way. In this regard, our tools of choice are the “GPS Toolkit” (GPSTk), and a modern, high power embedded platform such as the “Gumstix” computer boards. Peer Reviewed

The Formation and Early Evolution of Embedded Massive Star Clusters

Science.gov (United States)

Barnes, Peter

We propose to combine Spitzer, WISE, Herschel, and other archival spacecraft data with an existing ground- and space-based mm-wave to near-IR survey of molecular clouds over a large portion of the Milky Way, in order to systematically study the formation and early evolution of massive stars and star clusters, and provide new observational calibrations for a theoretical paradigm of this key astrophysical problem. Central Objectives: The Galactic Census of High- and Medium-mass Protostars (CHaMP) is a large, unbiased, uniform, and panchromatic survey of massive star and cluster formation and early evolution, covering 20°x6° of the Galactic Plane. Its uniqueness lies in the comprehensive molecular spectroscopy of 303 massive dense clumps, which have also been included in several archival spacecraft surveys. Our objective is a systematic demographic analysis of massive star and cluster formation, one which has not been possible without knowledge of our CHaMP cloud sample, including all clouds with embedded clusters as well as those that have not yet formed massive stars. For proto-clusters deeply embedded within dense molecular clouds, analysis of these space-based data will: 1. Yield a complete census of Young Stellar Objects in each cluster. 2. Allow systematic measurements of embedded cluster properties: spectral energy distributions, luminosity functions, protostellar and disk fractions, and how these vary with cluster mass, age, and density. Combined with other, similarly complete and unbiased infrared and mm data, CHaMP's goals include: 3. A detailed comparison of the embedded stellar populations with their natal dense gas to derive extinction maps, star formation efficiencies and feedback effects, and the kinematics, physics, and chemistry of the gas in and around the clusters. 4. Tying the demographics, age spreads, and timescales of the clusters, based on pre-Main Sequence evolution, to that of the dense gas clumps and Giant Molecular Clouds. 5. A

Co-simulation of Distributed Embedded Real-Time Control Systems

NARCIS (Netherlands)

Verhoef, M.; Visser, P.M.; Hooman, J.; Broenink, Johannes F.; Davies, J.; Gibbons, J.

2007-01-01

Development of computerized embedded control systems is difficult because it brings together systems theory, electrical engineering and computer science. The engineering and analysis approaches advocated by these disciplines are fundamentally different which complicates reasoning about e.g.

Introduction to Embedded Systems Using ANSI C and the Arduino Development Environment

CERN Document Server

Russell, David

2010-01-01

Many electrical and computer engineering projects involve some kind of embedded system in which a microcontroller sits at the center as the primary source of control. The recently-developed Arduino development platform includes an inexpensive hardware development board hosting an eight-bit ATMEL ATmega-family processor and a Java-based software-development environment. These features allow an embedded systems beginner the ability to focus their attention on learning how to write embedded software instead of wasting time overcoming the engineering CAD tools learning curve. The goal of this text

NASA Computational Case Study: The Flight of Friendship 7

Science.gov (United States)

Simpson, David G.

2012-01-01

In this case study, we learn how to compute the position of an Earth-orbiting spacecraft as a function of time. As an exercise, we compute the position of John Glenn's Mercury spacecraft Friendship 7 as it orbited the Earth during the third flight of NASA's Mercury program.

Research on applications of ARM-LINUX embedded systems in manufacturing the nuclear equipment

International Nuclear Information System (INIS)

Nguyen Van Sy; Phan Luong Tuan; Nguyen Xuan Vinh; Dang Quang Bao

2016-01-01

A new microprocessor system that is ARM processor with open source Linux operating system is studied with the objective to apply ARM-Linux embedded systems in manufacturing the nuclear equipment. We use the development board of the company to learn and to build the workflow for an embedded system, then basing on the knowledge we design a motherboard embedded systems interface with the peripherals is buttons, LEDs through GPIO interface and connected with GM counting system via RS232 interface. The results of this study are: i) The procedures for working with embedded systems: process customization, installation embedded operating system and installation process, configure the development tools on the host computer; ii) ARM-Linux motherboard embedded systems interface with the peripherals and GM counting system, indicating the counts from GM counting system on the touch screen. (author)

Application of Space Environmental Observations to Spacecraft Pre-Launch Engineering and Spacecraft Operations

Science.gov (United States)

Barth, Janet L.; Xapsos, Michael

2008-01-01

This presentation focuses on the effects of the space environment on spacecraft systems and applying this knowledge to spacecraft pre-launch engineering and operations. Particle radiation, neutral gas particles, ultraviolet and x-rays, as well as micrometeoroids and orbital debris in the space environment have various effects on spacecraft systems, including degradation of microelectronic and optical components, physical damage, orbital decay, biasing of instrument readings, and system shutdowns. Space climate and weather must be considered during the mission life cycle (mission concept, mission planning, systems design, and launch and operations) to minimize and manage risk to both the spacecraft and its systems. A space environment model for use in the mission life cycle is presented.

Benefits of Spacecraft Level Vibration Testing

Science.gov (United States)

Gordon, Scott; Kern, Dennis L.

2015-01-01

NASA-HDBK-7008 Spacecraft Level Dynamic Environments Testing discusses the approaches, benefits, dangers, and recommended practices for spacecraft level dynamic environments testing, including vibration testing. This paper discusses in additional detail the benefits and actual experiences of vibration testing spacecraft for NASA Goddard Space Flight Center (GSFC) and Jet Propulsion Laboratory (JPL) flight projects. JPL and GSFC have both similarities and differences in their spacecraft level vibration test approach: JPL uses a random vibration input and a frequency range usually starting at 5 Hz and extending to as high as 250 Hz. GSFC uses a sine sweep vibration input and a frequency range usually starting at 5 Hz and extending only to the limits of the coupled loads analysis (typically 50 to 60 Hz). However, both JPL and GSFC use force limiting to realistically notch spacecraft resonances and response (acceleration) limiting as necessary to protect spacecraft structure and hardware from exceeding design strength capabilities. Despite GSFC and JPL differences in spacecraft level vibration test approaches, both have uncovered a significant number of spacecraft design and workmanship anomalies in vibration tests. This paper will give an overview of JPL and GSFC spacecraft vibration testing approaches and provide a detailed description of spacecraft anomalies revealed.

Communicating LightSail: Embedded Reporting and Web Strategies for Citizen-Funded Space Missions

Science.gov (United States)

Hilverda, M.; Davis, J.

2015-12-01

The Planetary Society (TPS) is a non-profit space advocacy group with a stated mission to "empower the world's citizens to advance space science and exploration." In 2009, TPS began work on LightSail, a small, citizen-funded spacecraft to demonstrate solar sailing propulsion technology. The program included a test flight, completed in June 2015, with a primary mission slated for late 2016. TPS initiated a LightSail public engagement campaign to provide the public with transparent mission updates, and foster educational outreach. A credentialed science journalist was given unrestricted access to the team and data, and provided regular reports without editorial oversight. An accompanying website, sail.planetary.org, provided project updates, multimedia, and real-time spacecraft data during the mission. Design approaches included a clean layout with text optimized for easy reading, balanced by strong visual elements to enhance reader comprehension and interest. A dedicated "Mission Control" page featured social media feeds, links to most recent articles, and a ground track showing the spacecraft's position, including overflight predictions based on user location. A responsive, cross-platform design allowed easy access across a broad range of devices. Efficient web server performance was prioritized by implementing a static content management system (CMS). Despite two spacecraft contingencies, the test mission successfully completed its primary objective of solar sail deployment. Qualitative feedback on the transparent, embedded reporting style was positive, and website metrics showed high user retention times. The website also grew awareness and support for the primary 2016 mission, driving traffic to a Kickstarter campaign that raised $1.24 million. Websites constantly evolve, and changes for the primary mission will include a new CMS to better support multiple authors and a custom dashboard to display real-time spacecraft sensor data.

Learning for VMM + WTA Embedded Classifiers

Science.gov (United States)

2016-03-31

Learning for VMM + WTA Embedded Classifiers Jennifer Hasler and Sahil Shah Electrical and Computer Engineering Georgia Institute of Technology...enabling correct classification of each novel acoustic signal (generator, idle car, and idle truck ). The classification structure requires, after...measured on our SoC FPAA IC. The test input is composed of signals from urban environment for 3 objects (generator, idle car, and idle truck

Advanced Smart Structures Flight Experiments for Precision Spacecraft

Science.gov (United States)

Denoyer, Keith K.; Erwin, R. Scott; Ninneman, R. Rory

2000-07-01

This paper presents an overview as well as data from four smart structures flight experiments directed by the U.S. Air Force Research Laboratory's Space Vehicles Directorate in Albuquerque, New Mexico. The Middeck Active Control Experiment $¯Flight II (MACE II) is a space shuttle flight experiment designed to investigate modeling and control issues for achieving high precision pointing and vibration control of future spacecraft. The Advanced Controls Technology Experiment (ACTEX-I) is an experiment that has demonstrated active vibration suppression using smart composite structures with embedded piezoelectric sensors and actuators. The Satellite Ultraquiet Isolation Technology Experiment (SUITE) is an isolation platform that uses active piezoelectric actuators as well as damped mechanical flexures to achieve hybrid passive/active isolation. The Vibration Isolation, Suppression, and Steering Experiment (VISS) is another isolation platform that uses viscous dampers in conjunction with electromagnetic voice coil actuators to achieve isolation as well as a steering capability for an infra-red telescope.

Diamond High Assurance Security Program: Trusted Computing Exemplar

Science.gov (United States)

2002-09-01

computing component, the Embedded MicroKernel Prototype. A third-party evaluation of the component will be initiated during development (e.g., once...target technologies and larger projects is a topic for future research. Trusted Computing Reference Component – The Embedded MicroKernel Prototype We...Kernel The primary security function of the Embedded MicroKernel will be to enforce process and data-domain separation, while providing primitive

Computing Best and Worst Shortcuts of Graphs Embedded in Metric Spaces

DEFF Research Database (Denmark)

Wulff-Nilsen, Christian; Luo, Jun

2008-01-01

Given a graph embedded in a metric space, its dilation is the maximum over all distinct pairs of vertices of the ratio between their distance in the graph and the metric distance between them. Given such a graph G with n vertices and m edges and consisting of at most two connected components, we ...

Embedding Approach to Modeling Electromagnetic Fields in a Complex Two-Dimensional Environment

Directory of Open Access Journals (Sweden)

Anton Tijhuis

2018-01-01

Full Text Available An approach is presented to combine the response of a two-dimensionally inhomogeneous dielectric object in a homogeneous environment with that of an empty inhomogeneous environment. This allows an efficient computation of the scattering behavior of the dielectric cylinder with the aid of the CGFFT method and a dedicated extrapolation procedure. Since a circular observation contour is adopted, an angular spectral representation can be employed for the embedding. Implementation details are discussed for the case of a closed 434 MHz microwave scanner, and the accuracy and efficiency of all steps in the numerical procedure are investigated. Guidelines are proposed for choosing computational parameters such as truncation limits and tolerances. We show that the embedding approach does not increase the CPU time with respect to the forward problem solution in a homogeneous environment, if only the fields on the observation contour are computed, and that it leads to a relatively small increase when the fields on the mesh are computed as well.

Parallel embedded systems: where real-time and low-power meet

DEFF Research Database (Denmark)

Karakehayov, Zdravko; Guo, Yu

2008-01-01

This paper introduces a combination of models and proofs for optimal power management via Dynamic Frequency Scaling and Dynamic Voltage Scaling. The approach is suitable for systems on a chip or microcontrollers where processors run in parallel with embedded peripherals. We have developed...... a software tool, called CASTLE, to provide computer assistance in the design process of energy-aware embedded systems. The tool considers single processor and parallel architectures. An example shows an energy reduction of 23% when the tool allocates two microcontrollers for parallel execution....

An embedded formula of the Chebyshev collocation method for stiff problems

Science.gov (United States)

Piao, Xiangfan; Bu, Sunyoung; Kim, Dojin; Kim, Philsu

2017-12-01

In this study, we have developed an embedded formula of the Chebyshev collocation method for stiff problems, based on the zeros of the generalized Chebyshev polynomials. A new strategy for the embedded formula, using a pair of methods to estimate the local truncation error, as performed in traditional embedded Runge-Kutta schemes, is proposed. The method is performed in such a way that not only the stability region of the embedded formula can be widened, but by allowing the usage of larger time step sizes, the total computational costs can also be reduced. In terms of concrete convergence and stability analysis, the constructed algorithm turns out to have an 8th order convergence and it exhibits A-stability. Through several numerical experimental results, we have demonstrated that the proposed method is numerically more efficient, compared to several existing implicit methods.

The effects of perceived USB-delay for sensor and embedded system development.

Science.gov (United States)

Du, J; Kade, D; Gerdtman, C; Ozcan, O; Linden, M

2016-08-01

Perceiving delay in computer input devices is a problem which gets even more eminent when being used in healthcare applications and/or in small, embedded systems. Therefore, the amount of delay found as acceptable when using computer input devices was investigated in this paper. A device was developed to perform a benchmark test for the perception of delay. The delay can be set from 0 to 999 milliseconds (ms) between a receiving computer and an available USB-device. The USB-device can be a mouse, a keyboard or some other type of USB-connected input device. Feedback from performed user tests with 36 people form the basis for the determination of time limitations for the USB data processing in microprocessors and embedded systems without users' noticing the delay. For this paper, tests were performed with a personal computer and a common computer mouse, testing the perception of delays between 0 and 500 ms. The results of our user tests show that perceived delays up to 150 ms were acceptable and delays larger than 300 ms were not acceptable at all.

Embedded multiprocessors scheduling and synchronization

CERN Document Server

Sriram, Sundararajan

2009-01-01

Techniques for Optimizing Multiprocessor Implementations of Signal Processing ApplicationsAn indispensable component of the information age, signal processing is embedded in a variety of consumer devices, including cell phones and digital television, as well as in communication infrastructure, such as media servers and cellular base stations. Multiple programmable processors, along with custom hardware running in parallel, are needed to achieve the computation throughput required of such applications. Reviews important research in key areas related to the multiprocessor implementation of multi

A Real-Time Embedded Control System for Electro-Fused Magnesia Furnace

Directory of Open Access Journals (Sweden)

Fang Zheng

2013-01-01

Full Text Available Since smelting process of electro-fused magnesia furnace is a complicated process which has characteristics like complex operation conditions, strong nonlinearities, and strong couplings, traditional linear controller cannot control it very well. Advanced intelligent control strategy is a good solution to this kind of industrial process. However, advanced intelligent control strategy always involves huge programming task and hard debugging and maintaining problems. In this paper, a real-time embedded control system is proposed for the process control of electro-fused magnesia furnace based on intelligent control strategy and model-based design technology. As for hardware, an embedded controller based on an industrial Single Board Computer (SBC is developed to meet industrial field environment demands. As for software, a Linux based on Real-Time Application Interface (RTAI is used as the real-time kernel of the controller to improve its real-time performance. The embedded software platform is also modified to support generating embedded code automatically from Simulink/Stateflow models. Based on the proposed embedded control system, the intelligent embedded control software of electro-fused magnesium furnace can be directly generated from Simulink/Stateflow models. To validate the effectiveness of the proposed embedded control system, hardware-in-the-loop (HIL and industrial field experiments are both implemented. Experiments results show that the embedded control system works very well in both laboratory and industry environments.

First principles nickel-cadmium and nickel hydrogen spacecraft battery models

Energy Technology Data Exchange (ETDEWEB)

Timmerman, P.; Ratnakumar, B.V.; Distefano, S.

1996-02-01

The principles of Nickel-Cadmium and Nickel-Hydrogen spacecraft battery models are discussed. The Ni-Cd battery model includes two phase positive electrode and its predictions are very close to actual data. But the Ni-H2 battery model predictions (without the two phase positive electrode) are unacceptable even though the model is operational. Both models run on UNIX and Macintosh computers.

Improved Secret Image Sharing Scheme in Embedding Capacity without Underflow and Overflow.

Science.gov (United States)

Pang, Liaojun; Miao, Deyu; Li, Huixian; Wang, Qiong

2015-01-01

Computational secret image sharing (CSIS) is an effective way to protect a secret image during its transmission and storage, and thus it has attracted lots of attentions since its appearance. Nowadays, it has become a hot topic for researchers to improve the embedding capacity and eliminate the underflow and overflow situations, which is embarrassing and difficult to deal with. The scheme, which has the highest embedding capacity among the existing schemes, has the underflow and overflow problems. Although the underflow and overflow situations have been well dealt with by different methods, the embedding capacities of these methods are reduced more or less. Motivated by these concerns, we propose a novel scheme, in which we take the differential coding, Huffman coding, and data converting to compress the secret image before embedding it to further improve the embedding capacity, and the pixel mapping matrix embedding method with a newly designed matrix is used to embed secret image data into the cover image to avoid the underflow and overflow situations. Experiment results show that our scheme can improve the embedding capacity further and eliminate the underflow and overflow situations at the same time.

Embedded Empiricisms in Soft Soil Technology

Science.gov (United States)

Wijeyesekera, D. C.; John, L. M. S. Alvin; Adnan, Z.

2016-07-01

Civil engineers of today are continuously challenged by innovative projects that push further the knowledge boundaries with conceptual and/or ingenious solutions leading to the realization of that once was considered impossible in the realms of geotechnology. Some of the forward developments rely on empirical methods embedded within soft soil technology and the spectral realms of engineering in its entirety. Empiricisms unlike folklore are not always shrouded in mysticism but can find scientific reasoning to justify them being adopted in design and tangible construction projects. This lecture therefore is an outline exposition of how empiricism has been integrally embedded in total empirical beginnings in the evolution of soft soil technology from the Renaissance time, through the developments of soil mechanics in the 19th century which in turn has paved the way to the rise of computational soil mechanics. Developments in computational soil mechanics has always embraced and are founded on a wide backdrop of empirical geoenvironment simulations. However, it is imperative that a competent geotechnical engineer needs postgraduate training combined with empiricism that is based on years of well- winnowed practical experience to fathom the diverseness and complexity of nature. However, experience being regarded more highly than expertise can, perhaps inadvertently, inhibit development and innovation.

Four-spacecraft determination of magnetopause orientation, motion and thickness: comparison with results from single-spacecraft methods

Directory of Open Access Journals (Sweden)

S. E. Haaland

2004-04-01

Full Text Available In this paper, we use Cluster data from one magnetopause event on 5 July 2001 to compare predictions from various methods for determination of the velocity, orientation, and thickness of the magnetopause current layer. We employ established as well as new multi-spacecraft techniques, in which time differences between the crossings by the four spacecraft, along with the duration of each crossing, are used to calculate magnetopause speed, normal vector, and width. The timing is based on data from either the Cluster Magnetic Field Experiment (FGM or the Electric Field Experiment (EFW instruments. The multi-spacecraft results are compared with those derived from various single-spacecraft techniques, including minimum-variance analysis of the magnetic field and deHoffmann-Teller, as well as Minimum-Faraday-Residue analysis of plasma velocities and magnetic fields measured during the crossings. In order to improve the overall consistency between multi- and single-spacecraft results, we have also explored the use of hybrid techniques, in which timing information from the four spacecraft is combined with certain limited results from single-spacecraft methods, the remaining results being left for consistency checks. The results show good agreement between magnetopause orientations derived from appropriately chosen single-spacecraft techniques and those obtained from multi-spacecraft timing. The agreement between magnetopause speeds derived from single- and multi-spacecraft methods is quantitatively somewhat less good but it is evident that the speed can change substantially from one crossing to the next within an event. The magnetopause thickness varied substantially from one crossing to the next, within an event. It ranged from 5 to 10 ion gyroradii. The density profile was sharper than the magnetic profile: most of the density change occured in the earthward half of the magnetopause.

Key words. Magnetospheric physics (magnetopause, cusp and

Spacecraft Attitude Determination

DEFF Research Database (Denmark)

Bak, Thomas

This thesis describes the development of an attitude determination system for spacecraft based only on magnetic field measurements. The need for such system is motivated by the increased demands for inexpensive, lightweight solutions for small spacecraft. These spacecraft demands full attitude...... determination based on simple, reliable sensors. Meeting these objectives with a single vector magnetometer is difficult and requires temporal fusion of data in order to avoid local observability problems. In order to guaranteed globally nonsingular solutions, quaternions are generally the preferred attitude...... is a detailed study of the influence of approximations in the modeling of the system. The quantitative effects of errors in the process and noise statistics are discussed in detail. The third contribution is the introduction of these methods to the attitude determination on-board the Ørsted satellite...

Charging in the environment of large spacecraft

International Nuclear Information System (INIS)

Lai, S.T.

1993-01-01

This paper discusses some potential problems of spacecraft charging as a result of interactions between a large spacecraft, such as the Space Station, and its environment. Induced electric field, due to VXB effect, may be important for large spacecraft at low earth orbits. Differential charging, due to different properties of surface materials, may be significant when the spacecraft is partly in sunshine and partly in shadow. Triple-root potential jump condition may occur because of differential charging. Sudden onset of severe differential charging may occur when an electron or ion beam is emitted from the spacecraft. The beam may partially return to the ''hot spots'' on the spacecraft. Wake effects, due to blocking of ambient ion trajectories, may result in an undesirable negative potential region in the vicinity of a large spacecraft. Outgassing and exhaust may form a significant spacecraft induced environment; ionization may occur. Spacecraft charging and discharging may affect the electronic components on board

Results from active spacecraft potential control on the Geotail spacecraft

International Nuclear Information System (INIS)

Schmidt, R.; Arends, H.; Pedersen, A.

1995-01-01

A low and actively controlled electrostatic potential on the outer surfaces of a scientific spacecraft is very important for accurate measurements of cold plasma electrons and ions and the DC to low-frequency electric field. The Japanese/NASA Geotail spacecraft carriers as part of its scientific payload a novel ion emitter for active control of the electrostatic potential on the surface of the spacecraft. The aim of the ion emitter is to reduce the positive surface potential which is normally encountered in the outer magnetosphere when the spacecraft is sunlit. Ion emission clamps the surface potential to near the ambient plasma potential. Without emission control, Geotail has encountered plasma conditions in the lobes of the magnetotail which resulted in surface potentials of up to about +70 V. The ion emitter proves to be able to discharge the outer surfaces of the spacecraft and is capable of keeping the surface potential stable at about +2 V. This potential is measured with respect to one of the electric field probes which are current biased and thus kept at a potential slightly above the ambient plasma potential. The instrument uses the liquid metal field ion emission principle to emit indium ions. The ion beam energy is about 6 keV and the typical total emission current amounts to about 15 μA. Neither variations in the ambient plasma conditions nor operation of two electron emitters on Geotail produce significant variations of the controlled surface potential as long as the resulting electron emission currents remain much smaller than the ion emission current. Typical results of the active potential control are shown, demonstrating the surface potential reduction and its stability over time. 25 refs., 5 figs

An Application of the "Virtual Spacecraft" Concept in Evaluation of the Mars Pathfinder Lander Low Gain Antenna

Science.gov (United States)

Pogorzelski, R. J.; Beckon, R. J.

1997-01-01

The virtual spacecraft concept is embodied in a set of subsystems, either in the form of hardware or computational models, which together represent all, or a portion of, a spacecraft. For example, the telecommunications transponder may be a hardware prototype while the propulsion system may exist only as a simulation. As the various subsystems are realized in hardware, the spacecraft becomes progressively less virtual. This concept is enabled by JPL's Mission System Testbed which is a set of networked workstations running a message passing operating system called "TRAMEL" which stands for Task Remote Asynchronous Message Exchange Layer. Each simulation on the workstations, which may in fact be hardware controlled by the workstation, "publishes" its operating parameters on TRAMEL and other simulations requiring those parameters as input may "subscribe" to them. In this manner, the whole simulation operates as a single virtual system. This paper describes a simulation designed to evaluate a communications link between the earth and the Mars Pathfinder Lander module as it descends under a parachute through the Martian atmosphere toward the planet's surface. This link includes a transmitter and a low gain antenna on the spacecraft and a receiving antenna and receiver on the earth as well as a simulation of the dynamics of the spacecraft. The transmitter, the ground station antenna, the receiver and the dynamics are all simulated computationally while the spacecraft antenna is implemented in hardware on a very simple spacecraft mockup. The dynamics simulation is a record of one output of the ensemble of outputs of a Monte Carlo simulation of the descent. Additionally, the antenna/spacecraft mock-up system was simulated using APATCH, a shooting and bouncing ray code developed by Demaco, Inc. The antenna simulation, the antenna hardware, and the link simulation are all physically located in different facilities at JPL separated by several hundred meters and are linked via

A microkernel middleware architecture for distributed embedded real-zime systems

OpenAIRE

Pfeffer, Matthias

2001-01-01

A microkernel middleware architecture for distributed embedded real-zime systems / T. Ungerer ... - In: Symposium on Reliable Distributed Systems : Proceedings : October 28 - 31, 2001, New Orleans, Louisiana, USA. - Los Alamitos, Calif. [u.a.] : IEEE Computer Soc., 2001. - S. 218-226

Spacecraft attitude maneuver control using two parallel mounted 3-DOF spherical actuators

Directory of Open Access Journals (Sweden)

Guidan Li

2017-02-01

Full Text Available A parallel configuration using two 3-degree-of-freedom (3-DOF spherical electromagnetic momentum exchange actuators is investigated for large angle spacecraft attitude maneuvers. First, the full dynamic equations of motion for the spacecraft system are derived by the Newton-Euler method. To facilitate computation, virtual gimbal coordinate frames are established. Second, a nonlinear control law in terms of quaternions is developed via backstepping method. The proposed control law compensates the coupling torques arising from the spacecraft rotation, and is robust against the external disturbances. Then, the singularity problem is analyzed. To avoid singularities, a modified weighed Moore-Pseudo inverse velocity steering law based on null motion is proposed. The weighted matrices are carefully designed to switch the actuators and redistribute the control torques. The null motion is used to reorient the rotor away from the tilt angle saturation state. Finally, numerical simulations of rest-to-rest maneuvers are performed to validate the effectiveness of the proposed method.

Fractionated Spacecraft Architectures Seeding Study

National Research Council Canada - National Science Library

Mathieu, Charlotte; Weigel, Annalisa

2006-01-01

.... Models were developed from a customer-centric perspective to assess different fractionated spacecraft architectures relative to traditional spacecraft architectures using multi-attribute analysis...

Real-Time Video Convolutional Face Finder on Embedded Platforms

Directory of Open Access Journals (Sweden)

Mamalet Franck

2007-01-01

Full Text Available A high-level optimization methodology is applied for implementing the well-known convolutional face finder (CFF algorithm for real-time applications on mobile phones, such as teleconferencing, advanced user interfaces, image indexing, and security access control. CFF is based on a feature extraction and classification technique which consists of a pipeline of convolutions and subsampling operations. The design of embedded systems requires a good trade-off between performance and code size due to the limited amount of available resources. The followed methodology copes with the main drawbacks of the original implementation of CFF such as floating-point computation and memory allocation, in order to allow parallelism exploitation and perform algorithm optimizations. Experimental results show that our embedded face detection system can accurately locate faces with less computational load and memory cost. It runs on a 275 MHz Starcore DSP at 35 QCIF images/s with state-of-the-art detection rates and very low false alarm rates.

Real-Time Video Convolutional Face Finder on Embedded Platforms

Directory of Open Access Journals (Sweden)

Franck Mamalet

2007-03-01

Full Text Available A high-level optimization methodology is applied for implementing the well-known convolutional face finder (CFF algorithm for real-time applications on mobile phones, such as teleconferencing, advanced user interfaces, image indexing, and security access control. CFF is based on a feature extraction and classification technique which consists of a pipeline of convolutions and subsampling operations. The design of embedded systems requires a good trade-off between performance and code size due to the limited amount of available resources. The followed methodology copes with the main drawbacks of the original implementation of CFF such as floating-point computation and memory allocation, in order to allow parallelism exploitation and perform algorithm optimizations. Experimental results show that our embedded face detection system can accurately locate faces with less computational load and memory cost. It runs on a 275 MHz Starcore DSP at 35 QCIF images/s with state-of-the-art detection rates and very low false alarm rates.

Internet Technology on Spacecraft

Science.gov (United States)

Rash, James; Parise, Ron; Hogie, Keith; Criscuolo, Ed; Langston, Jim; Powers, Edward I. (Technical Monitor)

2000-01-01

The Operating Missions as Nodes on the Internet (OMNI) project has shown that Internet technology works in space missions through a demonstration using the UoSAT-12 spacecraft. An Internet Protocol (IP) stack was installed on the orbiting UoSAT-12 spacecraft and tests were run to demonstrate Internet connectivity and measure performance. This also forms the basis for demonstrating subsequent scenarios. This approach provides capabilities heretofore either too expensive or simply not feasible such as reconfiguration on orbit. The OMNI project recognized the need to reduce the risk perceived by mission managers and did this with a multi-phase strategy. In the initial phase, the concepts were implemented in a prototype system that includes space similar components communicating over the TDRS (space network) and the terrestrial Internet. The demonstration system includes a simulated spacecraft with sample instruments. Over 25 demonstrations have been given to mission and project managers, National Aeronautics and Space Administration (NASA), Department of Defense (DoD), contractor technologists and other decisions makers, This initial phase reached a high point with an OMNI demonstration given from a booth at the Johnson Space Center (JSC) Inspection Day 99 exhibition. The proof to mission managers is provided during this second phase with year 2000 accomplishments: testing the use of Internet technologies onboard an actual spacecraft. This was done with a series of tests performed using the UoSAT-12 spacecraft. This spacecraft was reconfigured on orbit at very low cost. The total period between concept and the first tests was only 6 months! On board software was modified to add an IP stack to support basic IP communications. Also added was support for ping, traceroute and network timing protocol (NTP) tests. These tests show that basic Internet functionality can be used onboard spacecraft. The performance of data was measured to show no degradation from current

Physical Activity Recognition from Smartphone Embedded Sensors

DEFF Research Database (Denmark)

Prudêncio, João; Aguiar, Ana; Roetter, Daniel Enrique Lucani

2013-01-01

The ubiquity of smartphones has motivated efforts to use the embedded sensors to detect various aspects of user context to transparently provide personalized and contextualized services to the user. One relevant piece of context is the physical activity of the smartphone user. In this paper, we...... propose a novel set of features for distinguishing five physical activities using only sensors embedded in the smartphone. Specifically, we introduce features that are normalized using the orientation sensor such that horizontal and vertical movements are explicitly computed. We evaluate a neural network...... classifier in experiments in the wild with multiple users and hardware, we achieve accuracies above 90% for a single user and phone, and above 65% for multiple users, which is higher that similar works on the same set of activities, demonstrating the potential of our approach....

Spacecraft momentum control systems

CERN Document Server

Leve, Frederick A; Peck, Mason A

2015-01-01

The goal of this book is to serve both as a practical technical reference and a resource for gaining a fuller understanding of the state of the art of spacecraft momentum control systems, specifically looking at control moment gyroscopes (CMGs). As a result, the subject matter includes theory, technology, and systems engineering. The authors combine material on system-level architecture of spacecraft that feature momentum-control systems with material about the momentum-control hardware and software. This also encompasses material on the theoretical and algorithmic approaches to the control of space vehicles with CMGs. In essence, CMGs are the attitude-control actuators that make contemporary highly agile spacecraft possible. The rise of commercial Earth imaging, the advances in privately built spacecraft (including small satellites), and the growing popularity of the subject matter in academic circles over the past decade argues that now is the time for an in-depth treatment of the topic. CMGs are augmented ...

Sensor Selection method for IoT systems – focusing on embedded system requirements

Directory of Open Access Journals (Sweden)

Hirayama Masayuki

2016-01-01

Full Text Available Recently, various types of sensors have been developed. Using these sensors, IoT systems have become hot topics in embedded system domain. However, sensor selections for embedded systems are not well discussed up to now. This paper focuses on embedded system’s features and architecture, and proposes a sensor selection method which is composed seven steps. In addition, we applied the proposed method to a simple example – a sensor selection for computer scored answer sheet reader unit. From this case study, an idea to use FTA in sensor selection is also discussed.

Engineering embedded systems physics, programs, circuits

CERN Document Server

Hintenaus, Peter

2015-01-01

This is a textbook for graduate and final-year-undergraduate computer-science and electrical-engineering students interested in the hardware and software aspects of embedded and cyberphysical systems design. It is comprehensive and self-contained, covering everything from the basics to case-study implementation. Emphasis is placed on the physical nature of the problem domain and of the devices used. The reader is assumed to be familiar on a theoretical level with mathematical tools like ordinary differential equation and Fourier transforms. In this book these tools will be put to practical use. Engineering Embedded Systems begins by addressing basic material on signals and systems, before introducing to electronics. Treatment of digital electronics accentuating synchronous circuits and including high-speed effects proceeds to micro-controllers, digital signal processors and programmable logic. Peripheral units and decentralized networks are given due weight. The properties of analog circuits and devices like ...

Generating Animated Displays of Spacecraft Orbits

Science.gov (United States)

Candey, Robert M.; Chimiak, Reine A.; Harris, Bernard T.

2005-01-01

Tool for Interactive Plotting, Sonification, and 3D Orbit Display (TIPSOD) is a computer program for generating interactive, animated, four-dimensional (space and time) displays of spacecraft orbits. TIPSOD utilizes the programming interface of the Satellite Situation Center Web (SSCWeb) services to communicate with the SSC logic and database by use of the open protocols of the Internet. TIPSOD is implemented in Java 3D and effects an extension of the preexisting SSCWeb two-dimensional static graphical displays of orbits. Orbits can be displayed in any or all of the following seven reference systems: true-of-date (an inertial system), J2000 (another inertial system), geographic, geomagnetic, geocentric solar ecliptic, geocentric solar magnetospheric, and solar magnetic. In addition to orbits, TIPSOD computes and displays Sibeck's magnetopause and Fairfield's bow-shock surfaces. TIPSOD can be used by the scientific community as a means of projection or interpretation. It also has potential as an educational tool.

Development and experimentation of LQR/APF guidance and control for autonomous proximity maneuvers of multiple spacecraft

Science.gov (United States)

Bevilacqua, R.; Lehmann, T.; Romano, M.

2011-04-01

This work introduces a novel control algorithm for close proximity multiple spacecraft autonomous maneuvers, based on hybrid linear quadratic regulator/artificial potential function (LQR/APF), for applications including autonomous docking, on-orbit assembly and spacecraft servicing. Both theoretical developments and experimental validation of the proposed approach are presented. Fuel consumption is sub-optimized in real-time through re-computation of the LQR at each sample time, while performing collision avoidance through the APF and a high level decisional logic. The underlying LQR/APF controller is integrated with a customized wall-following technique and a decisional logic, overcoming problems such as local minima. The algorithm is experimentally tested on a four spacecraft simulators test bed at the Spacecraft Robotics Laboratory of the Naval Postgraduate School. The metrics to evaluate the control algorithm are: autonomy of the system in making decisions, successful completion of the maneuver, required time, and propellant consumption.

Efficient physical embedding of topologically complex information processing networks in brains and computer circuits.

Directory of Open Access Journals (Sweden)

Danielle S Bassett

2010-04-01

Full Text Available Nervous systems are information processing networks that evolved by natural selection, whereas very large scale integrated (VLSI computer circuits have evolved by commercially driven technology development. Here we follow historic intuition that all physical information processing systems will share key organizational properties, such as modularity, that generally confer adaptivity of function. It has long been observed that modular VLSI circuits demonstrate an isometric scaling relationship between the number of processing elements and the number of connections, known as Rent's rule, which is related to the dimensionality of the circuit's interconnect topology and its logical capacity. We show that human brain structural networks, and the nervous system of the nematode C. elegans, also obey Rent's rule, and exhibit some degree of hierarchical modularity. We further show that the estimated Rent exponent of human brain networks, derived from MRI data, can explain the allometric scaling relations between gray and white matter volumes across a wide range of mammalian species, again suggesting that these principles of nervous system design are highly conserved. For each of these fractal modular networks, the dimensionality of the interconnect topology was greater than the 2 or 3 Euclidean dimensions of the space in which it was embedded. This relatively high complexity entailed extra cost in physical wiring: although all networks were economically or cost-efficiently wired they did not strictly minimize wiring costs. Artificial and biological information processing systems both may evolve to optimize a trade-off between physical cost and topological complexity, resulting in the emergence of homologous principles of economical, fractal and modular design across many different kinds of nervous and computational networks.

A Memory/Immunology-Based Control Approach with Applications to Multiple Spacecraft Formation Flying

Directory of Open Access Journals (Sweden)

Liguo Weng

2013-01-01

Full Text Available This paper addresses the problem of formation control for multiple spacecrafts in Planetary Orbital Environment (POE. Due to the presence of diverse interferences and uncertainties in the outer space, such as the changing spacecraft mass, unavailable space parameters, and varying gravity forces, traditional control methods encounter great difficulties in this area. A new control approach inspired by human memory and immune system is proposed, and this approach is shown to be capable of learning from past control experience and current behavior to improve its performance. It demands much less system dynamic information as compared with traditional controls. Both theoretic analysis and computer simulation verify its effectiveness.

Embedded systems handbook

CERN Document Server

Zurawski, Richard

2005-01-01

Embedded systems are nearly ubiquitous, and books on individual topics or components of embedded systems are equally abundant. Unfortunately, for those designers who thirst for knowledge of the big picture of embedded systems there is not a drop to drink. Until now. The Embedded Systems Handbook is an oasis of information, offering a mix of basic and advanced topics, new solutions and technologies arising from the most recent research efforts, and emerging trends to help you stay current in this ever-changing field.With preeminent contributors from leading industrial and academic institutions

Messaging Performance of FIPA Interaction Protocols in Networked Embedded Controllers

Directory of Open Access Journals (Sweden)

García JoséAPérez

2008-01-01

Full Text Available Abstract Agent-based technologies in production control systems could facilitate seamless reconfiguration and integration of mechatronic devices/modules into systems. Advances in embedded controllers which are continuously improving computational capabilities allow for software modularization and distribution of decisions. Agent platforms running on embedded controllers could hide the complexity of bootstrap and communication. Therefore, it is important to investigate the messaging performance of the agents whose main motivation is the resource allocation in manufacturing systems (i.e., conveyor system. The tests were implemented using the FIPA-compliant JADE-LEAP agent platform. Agent containers were distributed through networked embedded controllers, and agents were communicating using request and contract-net FIPA interaction protocols. The test scenarios are organized in intercontainer and intracontainer communications. The work shows the messaging performance for the different test scenarios using both interaction protocols.

Messaging Performance of FIPA Interaction Protocols in Networked Embedded Controllers

Directory of Open Access Journals (Sweden)

Omar Jehovani López Orozco

2007-12-01

Full Text Available Agent-based technologies in production control systems could facilitate seamless reconfiguration and integration of mechatronic devices/modules into systems. Advances in embedded controllers which are continuously improving computational capabilities allow for software modularization and distribution of decisions. Agent platforms running on embedded controllers could hide the complexity of bootstrap and communication. Therefore, it is important to investigate the messaging performance of the agents whose main motivation is the resource allocation in manufacturing systems (i.e., conveyor system. The tests were implemented using the FIPA-compliant JADE-LEAP agent platform. Agent containers were distributed through networked embedded controllers, and agents were communicating using request and contract-net FIPA interaction protocols. The test scenarios are organized in intercontainer and intracontainer communications. The work shows the messaging performance for the different test scenarios using both interaction protocols.

A low-cost high-performance embedded platform for accelerator controls

International Nuclear Information System (INIS)

Cleva, Stefano; Bogani, Alessio Igor; Pivetta, Lorenzo

2012-01-01

Over the last years the mobile and hand-held device market has seen a dramatic performance improvement of the microprocessors employed for these systems. As an interesting side effect, this brings the opportunity of adopting these microprocessors to build small low-cost embedded boards, featuring lots of processing power and input/output capabilities. Moreover, being capable of running a full featured operating system such as Gnu/Linux, and even a control system toolkit such as Tango, these boards can also be used in control systems as front-end or embedded computers. In order to evaluate the feasibility of this idea, an activity has started at Elettra to select, evaluate and validate a commercial embedded device able to guarantee production grade reliability, competitive costs and an open source platform. The preliminary results of this work are presented. (author)

Embedded System Implementation on FPGA System With μCLinux OS

International Nuclear Information System (INIS)

Amin, Ahmad Fairuz Muhd; Aris, Ishak; Abdullah, Raja Syamsul Azmir Raja; Sahbudin, Ratna Kalos Zakiah

2011-01-01

Embedded systems are taking on more complicated tasks as the processors involved become more powerful. The embedded systems have been widely used in many areas such as in industries, automotives, medical imaging, communications, speech recognition and computer vision. The complexity requirements in hardware and software nowadays need a flexibility system for further enhancement in any design without adding new hardware. Therefore, any changes in the design system will affect the processor that need to be changed. To overcome this problem, a System On Programmable Chip (SOPC) has been designed and developed using Field Programmable Gate Array (FPGA). A softcore processor, NIOS II 32-bit RISC, which is the microprocessor core was utilized in FPGA system together with the embedded operating system(OS), μClinux. In this paper, an example of web server is explained and demonstrated

Embedded System Implementation on FPGA System With μCLinux OS

Science.gov (United States)

Fairuz Muhd Amin, Ahmad; Aris, Ishak; Syamsul Azmir Raja Abdullah, Raja; Kalos Zakiah Sahbudin, Ratna

2011-02-01

Embedded systems are taking on more complicated tasks as the processors involved become more powerful. The embedded systems have been widely used in many areas such as in industries, automotives, medical imaging, communications, speech recognition and computer vision. The complexity requirements in hardware and software nowadays need a flexibility system for further enhancement in any design without adding new hardware. Therefore, any changes in the design system will affect the processor that need to be changed. To overcome this problem, a System On Programmable Chip (SOPC) has been designed and developed using Field Programmable Gate Array (FPGA). A softcore processor, NIOS II 32-bit RISC, which is the microprocessor core was utilized in FPGA system together with the embedded operating system(OS), μClinux. In this paper, an example of web server is explained and demonstrated

Embedded System Implementation on FPGA System With {mu}CLinux OS

Energy Technology Data Exchange (ETDEWEB)

Amin, Ahmad Fairuz Muhd [Institute of Advanced Technology, Universiti Putra Malaysia, 43400 Serdang, Selangor (Malaysia); Aris, Ishak [Department of Electrical and Electronic Engineering, Universiti Putra Malaysia, 43400, Serdang, Selangor (Malaysia); Abdullah, Raja Syamsul Azmir Raja; Sahbudin, Ratna Kalos Zakiah, E-mail: gs20613@mutiara.upm.edu.my, E-mail: ishak@eng.upm.edu.my, E-mail: rsa@eng.upm.edu.my [Department of Computer and Communication Systems Engineering, Universiti Putra Malaysia, 43400, Serdang, Selangor (Malaysia)

2011-02-15

Embedded systems are taking on more complicated tasks as the processors involved become more powerful. The embedded systems have been widely used in many areas such as in industries, automotives, medical imaging, communications, speech recognition and computer vision. The complexity requirements in hardware and software nowadays need a flexibility system for further enhancement in any design without adding new hardware. Therefore, any changes in the design system will affect the processor that need to be changed. To overcome this problem, a System On Programmable Chip (SOPC) has been designed and developed using Field Programmable Gate Array (FPGA). A softcore processor, NIOS II 32-bit RISC, which is the microprocessor core was utilized in FPGA system together with the embedded operating system(OS), {mu}Clinux. In this paper, an example of web server is explained and demonstrated

Development and Analysis of a Resource-Aware Power Management System as Applied to Small Spacecraft

Energy Technology Data Exchange (ETDEWEB)

Shriver, Patrick [Univ. of Colorado, Boulder, CO (United States)

2005-01-01

In this thesis, an overall framework and solution method for managing the limited power resources of a small spacecraft is presented. Analogous to mobile computing technology, a primary limiting factor is the available power resources. In spite of the millions of dollars budgeted for research and development over decades, improvements in battery efficiency remains low. This situation is exacerbated by advances in payload technology that lead to increasingly power-hungry and data-intensive instruments. The challenge for the small spacecraft is to maximize capabilities and performance while meeting difficult design requirements and small project budgets.

An innovative ultra-capacitor driven shape memory alloy actuator with an embedded control system

International Nuclear Information System (INIS)

Li, Peng; Song, Gangbing

2014-01-01

In this paper, an innovative ultra-capacitor driven shape memory alloy (SMA) actuator with an embedded control system is proposed targeting high power high-duty cycle SMA applications. The ultra-capacitor, which is capable of delivering massive amounts of instantaneous current in a compact dimension for high power applications, is chosen as the main component of the power supply. A specialized embedded system is designed from the ground up to control the ultra-capacitor driven SMA system. The control of the ultra-capacitor driven SMA is different from that of a regular constant voltage powered SMA system in that the energy and the voltage of the ultra-capacitor decrease as the system load increases. The embedded control system is also different from a computer-based control system in that it has limited computational power, and the control algorithm has to be designed to be simple while effective so that it can fit into the embedded system environment. The problem of a variable voltage power source induced by the use of the ultra-capacitor is solved by using a fuzzy PID (proportional integral and derivative) control. The method of using an ultra-capacitor to drive SMA actuators enabled SMA as a good candidate for high power high-duty cycle applications. The proposed embedded control system provides a good and ready-to-use solution for SMA high power applications. (paper)

The art of software thermal management for embedded systems

CERN Document Server

Benson, Mark

2014-01-01

This book introduces Software Thermal Management (STM) as a means of reducing power consumption in a computing system, in order to manage heat, improve component reliability, and increase system safety.  Readers will benefit from this pragmatic guide to the field of STM for embedded systems and its catalog of software power management techniques.  Since thermal management is a key bottleneck in embedded systems design, this book focuses on power as the root cause of heat. Since software has an enormous impact on power consumption in an embedded system, this book guides readers to manage heat effectively by understanding, categorizing, and developing new ways to reduce dynamic power. Whereas most books on thermal management describe mechanisms to remove heat, this book focuses on ways to avoid generating heat in the first place.   • Explains fundamentals of software thermal management, application techniques and advanced optimization strategies; • Describes a novel method for managing dynamic power, e...

Cluster PEACE observations of electrons of spacecraft origin

Directory of Open Access Journals (Sweden)

S. Szita

2001-09-01

Full Text Available The two PEACE (Plasma Electron And Current Experiment sensors on board each Cluster spacecraft sample the electron velocity distribution across the full 4 solid angle and the energy range 0.7 eV to 26 keV with a time resolution of 4 s. We present high energy and angular resolution 3D observations of electrons of spacecraft origin in the various environments encountered by the Cluster constellation, including a lunar eclipse interval where the spacecraft potential was reduced but remained positive, and periods of ASPOC (Active Spacecraft POtential Control operation which reduced the spacecraft potential. We demonstrate how the spacecraft potential may be found from a gradient change in the PEACE low energy spectrum, and show how the observed spacecraft electrons are confined by the spacecraft potential. We identify an intense component of the spacecraft electrons with energies equivalent to the spacecraft potential, the arrival direction of which is seen to change when ASPOC is switched on. Another spacecraft electron component, observed in the sunward direction, is reduced in the eclipse but unaffected by ASPOC, and we believe this component is produced in the analyser by solar UV. We find that PEACE anodes with a look direction along the spacecraft surfaces are more susceptible to spacecraft electron contamination than those which look perpendicular to the surface, which justifies the decision to mount PEACE with its field-of-view radially outward rather than tangentially.Key words. Magnetosheric physics (general or miscellaneous Space plasma physics (spacecraft sheaths, wakes, charging

Embedded systems handbook networked embedded systems

CERN Document Server

Zurawski, Richard

2009-01-01

Considered a standard industry resource, the Embedded Systems Handbook provided researchers and technicians with the authoritative information needed to launch a wealth of diverse applications, including those in automotive electronics, industrial automated systems, and building automation and control. Now a new resource is required to report on current developments and provide a technical reference for those looking to move the field forward yet again. Divided into two volumes to accommodate this growth, the Embedded Systems Handbook, Second Edition presents a comprehensive view on this area

Computing in high energy physics

International Nuclear Information System (INIS)

Hertzberger, L.O.; Hoogland, W.

1986-01-01

This book deals with advanced computing applications in physics, and in particular in high energy physics environments. The main subjects covered are networking; vector and parallel processing; and embedded systems. Also examined are topics such as operating systems, future computer architectures and commercial computer products. The book presents solutions that are foreseen as coping, in the future, with computing problems in experimental and theoretical High Energy Physics. In the experimental environment the large amounts of data to be processed offer special problems on-line as well as off-line. For on-line data reduction, embedded special purpose computers, which are often used for trigger applications are applied. For off-line processing, parallel computers such as emulator farms and the cosmic cube may be employed. The analysis of these topics is therefore a main feature of this volume

Multi-Spacecraft Study of Kinetic scale Turbulence Using MMS Observations in the Solar Wind

Science.gov (United States)

Chasapis, A.; Matthaeus, W. H.; Parashar, T.; Fuselier, S. A.; Maruca, B.; Burch, J.; Moore, T. E.; Phan, T.; Pollock, C. J.; Gershman, D. J.; Torbert, R. B.; Russell, C. T.; Strangeway, R. J.

2017-12-01

We present a study investigating kinetic scale turbulence in the solar wind. Most previous studies relied on single spacecraft measurements, employing the Taylor hypothesis in order to probe different scales. The small separation of MMS spacecraft, well below the ion inertial scale, allow us for the first time to directly probe turbulent fluctuations at the kinetic range. Using multi-spacecraft measurements, we are able to measure the spatial characteristics of turbulent fluctuations and compare with the traditional Taylor-based single spacecraft approach. Meanwhile, combining observations from Cluster and MMS data we were able to cover a wide range of scales from the inertial range where the turbulent cascade takes place, down to the kinetic range where the energy is eventually dissipated. These observations present an important step in understanding the nature of solar wind turbulence and the processes through which turbulent energy is dissipated into particle heating and acceleration. We compute statistical quantities such as the second order structure function and the scale-dependent kurtosis, along with their dependence on the parameters such as the mean magnetic field direction. Overall, we observe an overall agreement between the single spacecraft and the multi-spacecraft approach. However, a small but significant deviation is observed at the smaller scales near the electron inertial scale. The high values of the scale dependent kurtosis at very small scales, observed via two-point measurements, open up a compelling avenue of investigation for theory and numerical modelling.

Embedded systemen en Y2K: vijf voor twaalf

NARCIS (Netherlands)

Luiijf, H.A.M.

1998-01-01

Met de regelmaat van de klok is Jan D. Timmer te zien op TV. Als voorzitter van het Millennium platform vraagt hij aandacht voor het feit dat computers, apparatuur en embedded systemen bij de overgang naar het jaar-2OOO dienst kunnen weigeren of op een andere wijze problemen kunnen veroorzaken. Dit

Hilbert-Twin – A Novel Hilbert Transform-Based Method To Compute Envelope Of Free Decaying Oscillations Embedded In Noise, And The Logarithmic Decrement In High-Resolution Mechanical Spectroscopy HRMS

Directory of Open Access Journals (Sweden)

Magalas L.B.

2015-06-01

Full Text Available In this work, we present a novel Hilbert-twin method to compute an envelope and the logarithmic decrement, δ, from exponentially damped time-invariant harmonic strain signals embedded in noise. The results obtained from five computing methods: (1 the parametric OMI (Optimization in Multiple Intervals method, two interpolated discrete Fourier transform-based (IpDFT methods: (2 the Yoshida-Magalas (YM method and (3 the classic Yoshida (Y method, (4 the novel Hilbert-twin (H-twin method based on the Hilbert transform, and (5 the conventional Hilbert transform (HT method are analyzed and compared. The fundamental feature of the Hilbert-twin method is the efficient elimination of intrinsic asymmetrical oscillations of the envelope, aHT (t, obtained from the discrete Hilbert transform of analyzed signals. Excellent performance in estimation of the logarithmic decrement from the Hilbert-twin method is comparable to that of the OMI and YM for the low- and high-damping levels. The Hilbert-twin method proved to be robust and effective in computing the logarithmic decrement and the resonant frequency of exponentially damped free decaying signals embedded in experimental noise. The Hilbert-twin method is also appropriate to detect nonlinearities in mechanical loss measurements of metals and alloys.

Mechanical Design of Spacecraft

Science.gov (United States)

1962-01-01

In the spring of 1962, engineers from the Engineering Mechanics Division of the Jet Propulsion Laboratory gave a series of lectures on spacecraft design at the Engineering Design seminars conducted at the California Institute of Technology. Several of these lectures were subsequently given at Stanford University as part of the Space Technology seminar series sponsored by the Department of Aeronautics and Astronautics. Presented here are notes taken from these lectures. The lectures were conceived with the intent of providing the audience with a glimpse of the activities of a few mechanical engineers who are involved in designing, building, and testing spacecraft. Engineering courses generally consist of heavily idealized problems in order to allow the more efficient teaching of mathematical technique. Students, therefore, receive a somewhat limited exposure to actual engineering problems, which are typified by more unknowns than equations. For this reason it was considered valuable to demonstrate some of the problems faced by spacecraft designers, the processes used to arrive at solutions, and the interactions between the engineer and the remainder of the organization in which he is constrained to operate. These lecture notes are not so much a compilation of sophisticated techniques of analysis as they are a collection of examples of spacecraft hardware and associated problems. They will be of interest not so much to the experienced spacecraft designer as to those who wonder what part the mechanical engineer plays in an effort such as the exploration of space.

Modular Neural Tile Architecture for Compact Embedded Hardware Spiking Neural Network

NARCIS (Netherlands)

Pande, Sandeep; Morgan, Fearghal; Cawley, Seamus; Bruintjes, Tom; Smit, Gerardus Johannes Maria; McGinley, Brian; Carrillo, Snaider; Harkin, Jim; McDaid, Liam

2013-01-01

Biologically-inspired packet switched network on chip (NoC) based hardware spiking neural network (SNN) architectures have been proposed as an embedded computing platform for classification, estimation and control applications. Storage of large synaptic connectivity (SNN topology) information in

FMT (Flight Software Memory Tracker) For Cassini Spacecraft-Software Engineering Using JAVA

Science.gov (United States)

Kan, Edwin P.; Uffelman, Hal; Wax, Allan H.

1997-01-01

The software engineering design of the Flight Software Memory Tracker (FMT) Tool is discussed in this paper. FMT is a ground analysis software set, consisting of utilities and procedures, designed to track the flight software, i.e., images of memory load and updatable parameters of the computers on-board Cassini spacecraft. FMT is implemented in Java.

Embedded Linux in het onderwijs

NARCIS (Netherlands)

Dr Ruud Ermers

2008-01-01

Embedded Linux wordt bij steeds meer grote bedrijven ingevoerd als embedded operating system. Binnen de opleiding Technische Informatica van Fontys Hogeschool ICT is Embedded Linux geïntroduceerd in samenwerking met het lectoraat Architectuur van Embedded Systemen. Embedded Linux is als vakgebied

Accuracy & Computational Considerations for Wide--Angle One--way Seismic Propagators and Multiple Scattering by Invariant Embedding

Science.gov (United States)

Thomson, C. J.

2004-12-01

of computation time differences. The ideas described extend to the three--dimensional, generally anisotropic case and to multiple scattering by invariant embedding.

DNS and Embedded DNS as Tools for Investigating Unsteady Heat Transfer Phenomena in Turbines

Science.gov (United States)

vonTerzi, Dominic; Bauer, H.-J.

2010-01-01

DNS is a powerful tool with high potential for investigating unsteady heat transfer and fluid flow phenomena, in particular for cases involving transition to turbulence and/or large coherent structures. - DNS of idealized configurations related to turbomachinery components is already possible. - For more realistic configurations and the inclusion of more effects, reduction of computational cost is key issue (e.g., hybrid methods). - Approach pursued here: Embedded DNS ( segregated coupling of DNS with LES and/or RANS). - Embedded DNS is an enabling technology for many studies. - Pre-transitional heat transfer and trailing-edge cutback film-cooling are good candidates for (embedded) DNS studies.

Use of Faraday-rotation data from beacon satellites to determine ionospheric corrections for interplanetary spacecraft navigation

Science.gov (United States)

Royden, H. N.; Green, D. W.; Walson, G. R.

1981-01-01

Faraday-rotation data from the linearly polarized 137-MHz beacons of the ATS-1, SIRIO, and Kiku-2 geosynchronous satellites are used to determine the ionospheric corrections to the range and Doppler data for interplanetary spacecraft navigation. The JPL operates the Deep Space Network of tracking stations for NASA; these stations monitor Faraday rotation with dual orthogonal, linearly polarized antennas, Teledyne polarization tracking receivers, analog-to-digital converter/scanners, and other support equipment. Computer software examines the Faraday data, resolves the pi ambiguities, constructs a continuous Faraday-rotation profile and converts the profile to columnar zenith total electron content at the ionospheric reference point; a second program computes the line-of-sight ionospheric correction for each pass of the spacecraft over each tracking complex. Line-of-sight ionospheric electron content using mapped Faraday-rotation data is compared with that using dispersive Doppler data from the Voyager spacecraft; a difference of about 0.4 meters, or 5 x 10 to the 16th electrons/sq m is obtained. The technique of determining the electron content of interplanetary plasma by subtraction of the ionospheric contribution is demonstrated on the plasma torus surrounding the orbit of Io.

Cable Connected Spinning Spacecraft, 1. the Canonical Equations, 2. Urban Mass Transportation, 3

Science.gov (United States)

Sitchin, A.

1972-01-01

Work on the dynamics of cable-connected spinning spacecraft was completed by formulating the equations of motion by both the canonical equations and Lagrange's equations and programming them for numerical solution on a digital computer. These energy-based formulations will permit future addition of the effect of cable mass. Comparative runs indicate that the canonical formulation requires less computer time. Available literature on urban mass transportation was surveyed. Areas of the private rapid transit concept of urban transportation are also studied.

Embedding beyond electrostatics

DEFF Research Database (Denmark)

Nåbo, Lina J.; Olsen, Jógvan Magnus Haugaard; Holmgaard List, Nanna

2016-01-01

We study excited states of cholesterol in solution and show that, in this specific case, solute wave-function confinement is the main effect of the solvent. This is rationalized on the basis of the polarizable density embedding scheme, which in addition to polarizable embedding includes non-electrostatic...... repulsion that effectively confines the solute wave function to its cavity. We illustrate how the inclusion of non-electrostatic repulsion results in a successful identification of the intense π → π∗ transition, which was not possible using an embedding method that only includes electrostatics....... This underlines the importance of non-electrostatic repulsion in quantum-mechanical embedding-based methods....

Nonlinear model and attitude dynamics of flexible spacecraft with large amplitude slosh

Science.gov (United States)

Deng, Mingle; Yue, Baozeng

2017-04-01

This paper is focused on the nonlinearly modelling and attitude dynamics of spacecraft coupled with large amplitude liquid sloshing dynamics and flexible appendage vibration. The large amplitude fuel slosh dynamics is included by using an improved moving pulsating ball model. The moving pulsating ball model is an equivalent mechanical model that is capable of imitating the whole liquid reorientation process. A modification is introduced in the capillary force computation in order to more precisely estimate the settling location of liquid in microgravity or zero-g environment. The flexible appendage is modelled as a three dimensional Bernoulli-Euler beam and the assumed modal method is employed to derive the nonlinear mechanical model for the overall coupled system of liquid filled spacecraft with appendage. The attitude maneuver is implemented by the momentum transfer technique, and a feedback controller is designed. The simulation results show that the liquid sloshing can always result in nutation behavior, but the effect of flexible deformation of appendage depends on the amplitude and direction of attitude maneuver performed by spacecraft. Moreover, it is found that the liquid sloshing and the vibration of flexible appendage are coupled with each other, and the coupling becomes more significant with more rapid motion of spacecraft. This study reveals that the appendage's flexibility has influence on the liquid's location and settling time in microgravity. The presented nonlinear system model can provide an important reference for the overall design of the modern spacecraft composed of rigid platform, liquid filled tank and flexible appendage.

Spacecraft fabrication and test MODIL. Final report

Energy Technology Data Exchange (ETDEWEB)

Saito, T.T.

1994-05-01

This report covers the period from October 1992 through the close of the project. FY 92 closed out with the successful briefing to industry and with many potential and important initiatives in the spacecraft arena. Due to the funding uncertainties, we were directed to proceed as if our funding would be approximately the same as FY 92 ($2M), but not to make any major new commitments. However, the MODIL`s FY 93 funding was reduced to $810K and we were directed to concentrate on the cryocooler area. The cryocooler effort completed its demonstration project. The final meetings with the cryocooler fabricators were very encouraging as we witnessed the enthusiastic reception of technology to help them reduce fabrication uncertainties. Support of the USAF Phillips Laboratory cryocooler program was continued including kick-off meetings for the Prototype Spacecraft Cryocooler (PSC). Under Phillips Laboratory support, Gill Cruz visited British Aerospace and Lucas Aerospace in the United Kingdom to assess their manufacturing capabilities. In the Automated Spacecraft & Assembly Project (ASAP), contracts were pursued for the analysis by four Brilliant Eyes prime contractors to provide a proprietary snap shot of their current status of Integrated Product Development. In the materials and structure thrust the final analysis was completed of the samples made under the contract (``Partial Automation of Matched Metal Net Shape Molding of Continuous Fiber Composites``) to SPARTA. The Precision Technologies thrust funded the Jet Propulsion Laboratory to prepare a plan to develop a Computer Aided Alignment capability to significantly reduce the time for alignment and even possibly provide real time and remote alignment capability of systems in flight.

Thermal control system. [removing waste heat from industrial process spacecraft

Science.gov (United States)

Hewitt, D. R. (Inventor)

1983-01-01

The temperature of an exothermic process plant carried aboard an Earth orbiting spacecraft is regulated using a number of curved radiator panels accurately positioned in a circular arrangement to form an open receptacle. A module containing the process is insertable into the receptacle. Heat exchangers having broad exterior surfaces extending axially above the circumference of the module fit within arcuate spacings between adjacent radiator panels. Banks of variable conductance heat pipes partially embedded within and thermally coupled to the radiator panels extend across the spacings and are thermally coupled to broad exterior surfaces of the heat exchangers by flanges. Temperature sensors monitor the temperature of process fluid flowing from the module through the heat exchanges. Thermal conduction between the heat exchangers and the radiator panels is regulated by heating a control fluid within the heat pipes to vary the effective thermal length of the heat pipes in inverse proportion to changes in the temperature of the process fluid.

Deployable Brake for Spacecraft

Science.gov (United States)

Rausch, J. R.; Maloney, J. W.

1987-01-01

Aerodynamic shield that could be opened and closed proposed. Report presents concepts for deployable aerodynamic brake. Brake used by spacecraft returning from high orbit to low orbit around Earth. Spacecraft makes grazing passes through atmosphere to slow down by drag of brake. Brake flexible shield made of woven metal or ceramic withstanding high temperatures created by air friction. Stored until needed, then deployed by set of struts.

Ulysses spacecraft control and monitoring system

Science.gov (United States)

Hamer, P. A.; Snowden, P. J.

1991-01-01

The baseline Ulysses spacecraft control and monitoring system (SCMS) concepts and the converted SCMS, residing on a DEC/VAX 8350 hardware, are considered. The main functions of the system include monitoring and displaying spacecraft telemetry, preparing spacecraft commands, producing hard copies of experimental data, and archiving spacecraft telemetry. The SCMS system comprises over 20 subsystems ranging from low-level utility routines to the major monitoring and control software. These in total consist of approximately 55,000 lines of FORTRAN source code and 100 VMS command files. The SCMS major software facilities are described, including database files, telemetry processing, telecommanding, archiving of data, and display of telemetry.

Comparison of Component Frameworks for Real-Time Embedded Systems

Czech Academy of Sciences Publication Activity Database

Pop, T.; Hnětynka, P.; Hošek, P.; Malohlava, M.; Bureš, Tomáš

2014-01-01

Roč. 40, č. 1 (2014), s. 127-170 ISSN 0219-1377 Grant - others:GA AV ČR(CZ) GAP202/11/0312; GA UK(CZ) Project 378111; UK(CZ) SVV-2013- 267312 Keywords : component-based development * component frameworks * real-time and embedded systems Subject RIV: JC - Computer Hardware ; Software Impact factor: 1.782, year: 2014

Contemporary state of spacecraft/environment interaction research

CERN Document Server

Novikov, L S

1999-01-01

Various space environment effects on spacecraft materials and equipment, and the reverse effects of spacecrafts and rockets on space environment are considered. The necessity of permanent updating and perfection of our knowledge on spacecraft/environment interaction processes is noted. Requirements imposed on models of space environment in theoretical and experimental researches of various aspects of the spacecraft/environment interaction problem are formulated. In this field, main problems which need to be solved today and in the nearest future are specified. The conclusion is made that the joint analysis of both aspects of spacecraft/environment interaction problem promotes the most effective solution of the problem.

Final results of the Resonance spacecraft calibration effort

Science.gov (United States)

Sampl, Manfred; Macher, Wolfgang; Gruber, Christian; Oswald, Thomas; Rucker, Helmut O.

2010-05-01

We report our dedicated analyses of electrical field sensors onboard the Resonance spacecraft with a focus on the high-frequency electric antennas. The aim of the Resonance mission is to investigate wave-particle interactions and plasma dynamics in the inner magnetosphere of the Earth, with a focus on phenomena occurring along the same field line and within the same flux tube of the Earth's magnetic field. Four spacecraft will be launched, in the middle of the next decade, to perform these observations and measurements. Amongst a variety of instruments and probes several low- and high-frequency electric sensors will be carried which can be used for simultaneous remote sensing and in-situ measurements. The high-frequency electric sensors consist of cylindrical antennas mounted on four booms extruded from the central body of the spacecraft. In addition, the boom rods themselves are used together with the these sensors for mutual impedance measurements. Due to the parasitic effects of the conducting spacecraft body the electrical antenna representations (effective length vector, capacitances) do not coincide with their physical representations. The analysis of the reception properties of these antennas is presented, along with a contribution to the understanding of their impairment by other objects; in particular the influence of large magnetic loop sensors is studied. In order to analyse the antenna system, we applied experimental and numerical methods. The experimental method, called rheometry, is essentially an electrolytic tank measurement, where a scaled-down spacecraft model is immersed into an electrolytic medium (water) with corresponding measurements of voltages at the antennas. The numerical method consists of a numerical solution of the underlying field equations by means of computer programs, which are based on wire-grid and patch-grid models. The experimental and numerical results show that parasitic effects of the antenna-spacecraft assembly alter the

Gravity Probe B spacecraft description

International Nuclear Information System (INIS)

Bennett, Norman R; Burns, Kevin; Katz, Russell; Kirschenbaum, Jon; Mason, Gary; Shehata, Shawky

2015-01-01

The Gravity Probe B spacecraft, developed, integrated, and tested by Lockheed Missiles and Space Company and later Lockheed Martin Corporation, consisted of structures, mechanisms, command and data handling, attitude and translation control, electrical power, thermal control, flight software, and communications. When integrated with the payload elements, the integrated system became the space vehicle. Key requirements shaping the design of the spacecraft were: (1) the tight mission timeline (17 months, 9 days of on-orbit operation), (2) precise attitude and translational control, (3) thermal protection of science hardware, (4) minimizing aerodynamic, magnetic, and eddy current effects, and (5) the need to provide a robust, low risk spacecraft. The spacecraft met all mission requirements, as demonstrated by dewar lifetime meeting specification, positive power and thermal margins, precision attitude control and drag-free performance, reliable communications, and the collection of more than 97% of the available science data. (paper)

Embedded Web Technology: Internet Technology Applied to Real-Time System Control

Science.gov (United States)

Daniele, Carl J.

1998-01-01

The NASA Lewis Research Center is developing software tools to bridge the gap between the traditionally non-real-time Internet technology and the real-time, embedded-controls environment for space applications. Internet technology has been expanding at a phenomenal rate. The simple World Wide Web browsers (such as earlier versions of Netscape, Mosaic, and Internet Explorer) that resided on personal computers just a few years ago only enabled users to log into and view a remote computer site. With current browsers, users not only view but also interact with remote sites. In addition, the technology now supports numerous computer platforms (PC's, MAC's, and Unix platforms), thereby providing platform independence.In contrast, the development of software to interact with a microprocessor (embedded controller) that is used to monitor and control a space experiment has generally been a unique development effort. For each experiment, a specific graphical user interface (GUI) has been developed. This procedure works well for a single-user environment. However, the interface for the International Space Station (ISS) Fluids and Combustion Facility will have to enable scientists throughout the world and astronauts onboard the ISS, using different computer platforms, to interact with their experiments in the Fluids and Combustion Facility. Developing a specific GUI for all these users would be cost prohibitive. An innovative solution to this requirement, developed at Lewis, is to use Internet technology, where the general problem of platform independence has already been partially solved, and to leverage this expanding technology as new products are developed. This approach led to the development of the Embedded Web Technology (EWT) program at Lewis, which has the potential to significantly reduce software development costs for both flight and ground software.

Type-based homeomorphic embedding for online termination

DEFF Research Database (Denmark)

Albert, Elvira; Gallagher, John Patrick; Gómez-Zamalloa, Miguel

2009-01-01

that the computations supervised are performed over a finite signature, i.e., the number of constants and function symbols involved is finite. However, there are many situations, for example numeric computations, which involve an infinite signature and thus HEm does not guarantee termination. Some extensions to HEm...... for the case of infinite signatures have been proposed which guarantee termination. However, the existing techniques either do not provide systematic means for generating such extensions or the extensions are too simplistic and do not produce the expected results in practice. We propose Type-based Homeomorphic...... Embedding (TbHEm) as an extension of the standard, untyped, HEm. By taking static information about the behavior of the computation into account, expressed as types, TbHEm allows obtaining more precise results than those of the previous extensions to HEm for the case of infinite signatures. We show...

Modeling and Analysis of Realistic Fire Scenarios in Spacecraft

Science.gov (United States)

Brooker, J. E.; Dietrich, D. L.; Gokoglu, S. A.; Urban, D. L.; Ruff, G. A.

2015-01-01

An accidental fire inside a spacecraft is an unlikely, but very real emergency situation that can easily have dire consequences. While much has been learned over the past 25+ years of dedicated research on flame behavior in microgravity, a quantitative understanding of the initiation, spread, detection and extinguishment of a realistic fire aboard a spacecraft is lacking. Virtually all combustion experiments in microgravity have been small-scale, by necessity (hardware limitations in ground-based facilities and safety concerns in space-based facilities). Large-scale, realistic fire experiments are unlikely for the foreseeable future (unlike in terrestrial situations). Therefore, NASA will have to rely on scale modeling, extrapolation of small-scale experiments and detailed numerical modeling to provide the data necessary for vehicle and safety system design. This paper presents the results of parallel efforts to better model the initiation, spread, detection and extinguishment of fires aboard spacecraft. The first is a detailed numerical model using the freely available Fire Dynamics Simulator (FDS). FDS is a CFD code that numerically solves a large eddy simulation form of the Navier-Stokes equations. FDS provides a detailed treatment of the smoke and energy transport from a fire. The simulations provide a wealth of information, but are computationally intensive and not suitable for parametric studies where the detailed treatment of the mass and energy transport are unnecessary. The second path extends a model previously documented at ICES meetings that attempted to predict maximum survivable fires aboard space-craft. This one-dimensional model implies the heat and mass transfer as well as toxic species production from a fire. These simplifications result in a code that is faster and more suitable for parametric studies (having already been used to help in the hatch design of the Multi-Purpose Crew Vehicle, MPCV).

Embedded systems analysis and modeling with SysML, UML and AADL

CERN Document Server

Kordon, Fabrice; Canals , Agusti; Dohet , Alain

2013-01-01

Since the construction of the first embedded system in the 1960s, embedded systems have continued to spread. They provide a continually increasing number of services and are part of our daily life. The development of these systems is a difficult problem which does not yet have a global solution. Another difficulty is that systems are plunged into the real world, which is not discrete (as is generally understood in computing), but has a richness of behaviors which sometimes hinders the formulation of simplifying assumptions due to their generally autonomous nature and they must face possibly

Estimating Torque Imparted on Spacecraft Using Telemetry

Science.gov (United States)

Lee, Allan Y.; Wang, Eric K.; Macala, Glenn A.

2013-01-01

There have been a number of missions with spacecraft flying by planetary moons with atmospheres; there will be future missions with similar flybys. When a spacecraft such as Cassini flies by a moon with an atmosphere, the spacecraft will experience an atmospheric torque. This torque could be used to determine the density of the atmosphere. This is because the relation between the atmospheric torque vector and the atmosphere density could be established analytically using the mass properties of the spacecraft, known drag coefficient of objects in free-molecular flow, and the spacecraft velocity relative to the moon. The density estimated in this way could be used to check results measured by science instruments. Since the proposed methodology could estimate disturbance torque as small as 0.02 N-m, it could also be used to estimate disturbance torque imparted on the spacecraft during high-altitude flybys.

Embedded defects

International Nuclear Information System (INIS)

Barriola, M.; Vachaspati, T.; Bucher, M.

1994-01-01

We give a prescription for embedding classical solutions and, in particular, topological defects in field theories which are invariant under symmetry groups that are not necessarily simple. After providing examples of embedded defects in field theories based on simple groups, we consider the electroweak model and show that it contains the Z string and a one-parameter family of strings called the W(α) string. It is argued that although the members of this family are gauge equivalent when considered in isolation, each member becomes physically distinct when multistring configurations are considered. We then turn to the issue of stability of embedded defects and demonstrate the instability of a large class of such solutions in the absence of bound states or condensates. The Z string is shown to be unstable for all values of the Higgs boson mass when θ W =π/4. W strings are also shown to be unstable for a large range of parameters. Embedded monopoles suffer from the Brandt-Neri-Coleman instability. Finally, we connect the electroweak string solutions to the sphaleron

Design and Implementation of an Embedded NIOS II System for JPEG2000 Tier II Encoding

Directory of Open Access Journals (Sweden)

John M. McNichols

2013-01-01

Full Text Available This paper presents a novel implementation of the JPEG2000 standard as a system on a chip (SoC. While most of the research in this field centers on acceleration of the EBCOT Tier I encoder, this work focuses on an embedded solution for EBCOT Tier II. Specifically, this paper proposes using an embedded softcore processor to perform Tier II processing as the back end of an encoding pipeline. The Altera NIOS II processor is chosen for the implementation and is coupled with existing embedded processing modules to realize a fully embedded JPEG2000 encoder. The design is synthesized on a Stratix IV FPGA and is shown to out perform other comparable SoC implementations by 39% in computation time.

Integrated Design Tools for Embedded Control Systems

OpenAIRE

Jovanovic, D.S.; Hilderink, G.H.; Broenink, Johannes F.; Karelse, F.

2001-01-01

Currently, computer-based control systems are still being implemented using the same techniques as 10 years ago. The purpose of this project is the development of a design framework, consisting of tools and libraries, which allows the designer to build high reliable heterogeneous real-time embedded systems in a very short time at a fraction of the present day costs. The ultimate focus of current research is on transformation control laws to efficient concurrent algorithms, with concerns about...

Polymorphic Embedding of DSLs

DEFF Research Database (Denmark)

Hofer, Christian; Ostermann, Klaus; Rendel, Tillmann

2008-01-01

propose polymorphic embedding of DSLs, where many different interpretations of a DSL can be provided as reusable components, and show how polymorphic embedding can be realized in the programming language Scala. With polymorphic embedding, the static type-safety, modularity, composability and rapid...

Attitude coordination for spacecraft formation with multiple communication delays

Directory of Open Access Journals (Sweden)

Guo Yaohua

2015-04-01

Full Text Available Communication delays are inherently present in information exchange between spacecraft and have an effect on the control performance of spacecraft formation. In this work, attitude coordination control of spacecraft formation is addressed, which is in the presence of multiple communication delays between spacecraft. Virtual system-based approach is utilized in case that a constant reference attitude is available to only a part of the spacecraft. The feedback from the virtual systems to the spacecraft formation is introduced to maintain the formation. Using backstepping control method, input torque of each spacecraft is designed such that the attitude of each spacecraft converges asymptotically to the states of its corresponding virtual system. Furthermore, the backstepping technique and the Lyapunov–Krasovskii method contribute to the control law design when the reference attitude is time-varying and can be obtained by each spacecraft. Finally, effectiveness of the proposed methodology is illustrated by the numerical simulations of a spacecraft formation.

Sequence embedding for fast construction of guide trees for multiple sequence alignment

LENUS (Irish Health Repository)

Blackshields, Gordon

2010-05-14

Abstract Background The most widely used multiple sequence alignment methods require sequences to be clustered as an initial step. Most sequence clustering methods require a full distance matrix to be computed between all pairs of sequences. This requires memory and time proportional to N 2 for N sequences. When N grows larger than 10,000 or so, this becomes increasingly prohibitive and can form a significant barrier to carrying out very large multiple alignments. Results In this paper, we have tested variations on a class of embedding methods that have been designed for clustering large numbers of complex objects where the individual distance calculations are expensive. These methods involve embedding the sequences in a space where the similarities within a set of sequences can be closely approximated without having to compute all pair-wise distances. Conclusions We show how this approach greatly reduces computation time and memory requirements for clustering large numbers of sequences and demonstrate the quality of the clusterings by benchmarking them as guide trees for multiple alignment. Source code is available for download from http:\\/\\/www.clustal.org\\/mbed.tgz.

SHARP - Automated monitoring of spacecraft health and status

Science.gov (United States)

Atkinson, David J.; James, Mark L.; Martin, R. G.

1990-01-01

Briefly discussed here are the spacecraft and ground systems monitoring process at the Jet Propulsion Laboratory (JPL). Some of the difficulties associated with the existing technology used in mission operations are highlighted. A new automated system based on artificial intelligence technology is described which seeks to overcome many of these limitations. The system, called the Spacecraft Health Automated Reasoning Prototype (SHARP), is designed to automate health and status analysis for multi-mission spacecraft and ground data systems operations. The system has proved to be effective for detecting and analyzing potential spacecraft and ground systems problems by performing real-time analysis of spacecraft and ground data systems engineering telemetry. Telecommunications link analysis of the Voyager 2 spacecraft was the initial focus for evaluation of the system in real-time operations during the Voyager spacecraft encounter with Neptune in August 1989.

SHARP: Automated monitoring of spacecraft health and status

Science.gov (United States)

Atkinson, David J.; James, Mark L.; Martin, R. Gaius

1991-01-01

Briefly discussed here are the spacecraft and ground systems monitoring process at the Jet Propulsion Laboratory (JPL). Some of the difficulties associated with the existing technology used in mission operations are highlighted. A new automated system based on artificial intelligence technology is described which seeks to overcome many of these limitations. The system, called the Spacecraft Health Automated Reasoning Prototype (SHARP), is designed to automate health and status analysis for multi-mission spacecraft and ground data systems operations. The system has proved to be effective for detecting and analyzing potential spacecraft and ground systems problems by performing real-time analysis of spacecraft and ground data systems engineering telemetry. Telecommunications link analysis of the Voyager 2 spacecraft was the initial focus for evaluation of the system in real-time operations during the Voyager spacecraft encounter with Neptune in August 1989.

Marginalized particle filter for spacecraft attitude estimation from vector measurements

Institute of Scientific and Technical Information of China (English)

Yaqiu LIU; Xueyuan JIANG; Guangfu MA

2007-01-01

An algorithm based on the marginalized particle filters(MPF)is given in details in this paper to solve the spacecraft attitude estimation problem:attitude and gyro bias estimation using the biased gyro and vector observations.In this algorithm,by marginalizing out the state appearing linearly in the spacecraft model,the Kalman filter is associated with each particle in order to reduce the size of the state space and computational burden.The distribution of attitude vector is approximated by a set of particles and estimated using particle filter,while the estimation of gyro bias is obtained for each one of the attitude particles by applying the Kalman filter.The efficiency of this modified MPF estimator is verified through numerical simulation of a fully actuated rigid body.For comparison,unscented Kalman filter(UKF)is also used to gauge the performance of MPF.The results presented in this paper clearly demonstrate that the MPF is superior to UKF in coping with the nonlinear model.

Computer simulations of collisionless shock waves

International Nuclear Information System (INIS)

Leroy, M.M.

1984-01-01

A review of the contributions of particle computer simulations to the understanding of the physics of magnetic shock waves in collisionless plasmas is presented. The emphasis is on the relation between the computer simulation results, spacecraft observations of shocks in space, and related theories, rather than on technical aspects of the numerics. It is shown that much has been learned from the comparison of ISEE spacecraft observations of the terrestrial bow shock and particle computer simulations concerning the quasi-perpendicular, supercritical shock (ion scale structure, ion reflection mechanism and ultimate dissipation processes). Particle computer simulations have also had an appreciable prospective role in the investigation of the physics of quasi-parallel shocks, about which still little is known observationally. Moreover, these numerical techniques have helped to clarify the process of suprathermal ion rejection by the shock into the foreshock, and the subsequent evolution of the ions in the foreshock. 95 references

An introduction to NASA's advanced computing program: Integrated computing systems in advanced multichip modules

Science.gov (United States)

Fang, Wai-Chi; Alkalai, Leon

1996-01-01

Recent changes within NASA's space exploration program favor the design, implementation, and operation of low cost, lightweight, small and micro spacecraft with multiple launches per year. In order to meet the future needs of these missions with regard to the use of spacecraft microelectronics, NASA's advanced flight computing (AFC) program is currently considering industrial cooperation and advanced packaging architectures. In relation to this, the AFC program is reviewed, considering the design and implementation of NASA's AFC multichip module.

PERANCANGAN KANAL KOMUNIKASI PADA TRANSACTION LEVEL MODELING DALAM PERANCANGAN EMBEDDED SYSTEM

Directory of Open Access Journals (Sweden)

Maman Abdurohman

2012-05-01

Full Text Available Pada embedded system terdapat dua bagian penting yaitu komponen komputasi (register dan komponen komunikasi. Komponen komunikasi menjadi perhatian penting pada mekanisme pemodelan level transaksi (Transaction Level Modeling, TLM. Kanal komunikasi adalah komponen untuk transaksi antar register. Fokus pembahasan TLM adalah perancangan kanal yang dapat mengakomodasi untuk peningkatan level transaksi. Kanal (channel adalah implementasi bus untuk komunikasi antar komponen pada embedded system. Hal ini adalah kunci penting untuk mencapai impelementasi TLM untuk meningkatkan efisiensi pemodelan. Pada paper ini diusulkan beberapa definisi rancangan kanal sebagai implementasi TLM untuk perancangan embedded system. Hasilnya menunjukan bahwa rancangan kanal dapat berjalan sebagai bus untuk transaksi pada TLM. Paper ini menggunakan SystemC sebagai bahasa pemodelan. On embedded systems, there are two important parts: computational components (registers and communication components. Communication component becomes an important attention on the mechanism of transaction level modeling (TLM. Communication channel is a component for transactions between registers. The focus of TLM is the design of the channel that could accommodate for the increased level of transactions. Channel is the implementation of the bus for communication between components in embedded systems. This is an important key to achieve the implementation of TLM to improve the efficiency of modeling. This paper proposed a definition of the channel design as the implementation of TLM for embedded systems design. The result shows that the design of the channel can run as a bus for transactions on the TLM. This paper uses SystemC as modeling language.

Time-dependent embedding

OpenAIRE

Inglesfield, J. E.

2007-01-01

A method of solving the time-dependent Schr\\"odinger equation is presented, in which a finite region of space is treated explicitly, with the boundary conditions for matching the wave-functions on to the rest of the system replaced by an embedding term added on to the Hamiltonian. This time-dependent embedding term is derived from the Fourier transform of the energy-dependent embedding potential, which embeds the time-independent Schr\\"odinger equation. Results are presented for a one-dimensi...

Field tests on partial embedment effects (embedment effect tests on soil-structure interaction)

International Nuclear Information System (INIS)

Kurimoto, O.; Tsunoda, T.; Inoue, T.; Izumi, M.; Kusakabe, K.; Akino, K.

1993-01-01

A series of Model Tests of Embedment Effect on Reactor Buildings has been carried out by the Nuclear Power Engineering Corporation (NUPEC), under the sponsorship of the Ministry of International Trade and lndustry (MITI) of Japan. The nuclear reactor buildings are partially embedded due to conditions for the construction or building arrangement in Japan. It is necessary to verify the partial embedment effects by experiments and analytical studies in order to incorporate the effects in the seismic design. Forced vibration tests, therefore, were performed using a model with several types of embedment. Correlated simulation analyses were also performed and the characteristics of partial embedment effects on soil-structure interaction were evaluated. (author)

An Embedded Ghost-Fluid Method for Compressible Flow in Complex Geometry

KAUST Repository

Almarouf, Mohamad Abdulilah Alhusain Alali

2016-06-03

We present an embedded ghost-fluid method for numerical solutions of the compressible Navier Stokes (CNS) equations in arbitrary complex domains. The PDE multidimensional extrapolation approach of Aslam [1] is used to reconstruct the solution in the ghost-fluid regions and impose boundary conditions at the fluid-solid interface. The CNS equations are numerically solved by the second order multidimensional upwind method of Colella [2] and Saltzman [3]. Block-structured adaptive mesh refinement implemented under the Chombo framework is utilized to reduce the computational cost while keeping high-resolution mesh around the embedded boundary and regions of high gradient solutions. Numerical examples with different Reynolds numbers for low and high Mach number flow will be presented. We compare our simulation results with other reported experimental and computational results. The significance and advantages of our implementation, which revolve around balancing between the solution accuracy and implementation difficulties, are briefly discussed as well. © 2016 Trans Tech Publications.

An Embedded Ghost-Fluid Method for Compressible Flow in Complex Geometry

KAUST Repository

Almarouf, Mohamad Abdulilah Alhusain Alali; Samtaney, Ravi

2016-01-01

We present an embedded ghost-fluid method for numerical solutions of the compressible Navier Stokes (CNS) equations in arbitrary complex domains. The PDE multidimensional extrapolation approach of Aslam [1] is used to reconstruct the solution in the ghost-fluid regions and impose boundary conditions at the fluid-solid interface. The CNS equations are numerically solved by the second order multidimensional upwind method of Colella [2] and Saltzman [3]. Block-structured adaptive mesh refinement implemented under the Chombo framework is utilized to reduce the computational cost while keeping high-resolution mesh around the embedded boundary and regions of high gradient solutions. Numerical examples with different Reynolds numbers for low and high Mach number flow will be presented. We compare our simulation results with other reported experimental and computational results. The significance and advantages of our implementation, which revolve around balancing between the solution accuracy and implementation difficulties, are briefly discussed as well. © 2016 Trans Tech Publications.

Compact FPGA hardware architecture for public key encryption in embedded devices.

Science.gov (United States)

Rodríguez-Flores, Luis; Morales-Sandoval, Miguel; Cumplido, René; Feregrino-Uribe, Claudia; Algredo-Badillo, Ignacio

2018-01-01

Security is a crucial requirement in the envisioned applications of the Internet of Things (IoT), where most of the underlying computing platforms are embedded systems with reduced computing capabilities and energy constraints. In this paper we present the design and evaluation of a scalable low-area FPGA hardware architecture that serves as a building block to accelerate the costly operations of exponentiation and multiplication in [Formula: see text], commonly required in security protocols relying on public key encryption, such as in key agreement, authentication and digital signature. The proposed design can process operands of different size using the same datapath, which exhibits a significant reduction in area without loss of efficiency if compared to representative state of the art designs. For example, our design uses 96% less standard logic than a similar design optimized for performance, and 46% less resources than other design optimized for area. Even using fewer area resources, our design still performs better than its embedded software counterparts (190x and 697x).

Embedded Systems Design: Optimization Challenges

DEFF Research Database (Denmark)

Pop, Paul

2005-01-01

Summary form only given. Embedded systems are everywhere: from alarm clocks to PDAs, from mobile phones to cars, almost all the devices we use are controlled by embedded systems. Over 99% of the microprocessors produced today are used in embedded systems, and recently the number of embedded systems...

Spacecraft Charging: Hazard Causes, Hazard Effects, Hazard Controls

Science.gov (United States)

Koontz, Steve.

2018-01-01

Spacecraft flight environments are characterized both by a wide range of space plasma conditions and by ionizing radiation (IR), solar ultraviolet and X-rays, magnetic fields, micrometeoroids, orbital debris, and other environmental factors, all of which can affect spacecraft performance. Dr. Steven Koontz's lecture will provide a solid foundation in the basic engineering physics of spacecraft charging and charging effects that can be applied to solving practical spacecraft and spacesuit engineering design, verification, and operations problems, with an emphasis on spacecraft operations in low-Earth orbit, Earth's magnetosphere, and cis-Lunar space.

Automating Trend Analysis for Spacecraft Constellations

Science.gov (United States)

Davis, George; Cooter, Miranda; Updike, Clark; Carey, Everett; Mackey, Jennifer; Rykowski, Timothy; Powers, Edward I. (Technical Monitor)

2001-01-01

Spacecraft trend analysis is a vital mission operations function performed by satellite controllers and engineers, who perform detailed analyses of engineering telemetry data to diagnose subsystem faults and to detect trends that may potentially lead to degraded subsystem performance or failure in the future. It is this latter function that is of greatest importance, for careful trending can often predict or detect events that may lead to a spacecraft's entry into safe-hold. Early prediction and detection of such events could result in the avoidance of, or rapid return to service from, spacecraft safing, which not only results in reduced recovery costs but also in a higher overall level of service for the satellite system. Contemporary spacecraft trending activities are manually intensive and are primarily performed diagnostically after a fault occurs, rather than proactively to predict its occurrence. They also tend to rely on information systems and software that are oudated when compared to current technologies. When coupled with the fact that flight operations teams often have limited resources, proactive trending opportunities are limited, and detailed trend analysis is often reserved for critical responses to safe holds or other on-orbit events such as maneuvers. While the contemporary trend analysis approach has sufficed for current single-spacecraft operations, it will be unfeasible for NASA's planned and proposed space science constellations. Missions such as the Dynamics, Reconnection and Configuration Observatory (DRACO), for example, are planning to launch as many as 100 'nanospacecraft' to form a homogenous constellation. A simple extrapolation of resources and manpower based on single-spacecraft operations suggests that trending for such a large spacecraft fleet will be unmanageable, unwieldy, and cost-prohibitive. It is therefore imperative that an approach to automating the spacecraft trend analysis function be studied, developed, and applied to

Radiation Effects on Spacecraft Structural Materials

International Nuclear Information System (INIS)

Wang, Jy-An J.; Ellis, Ronald J.; Hunter, Hamilton T.; Singleterry, Robert C. Jr.

2002-01-01

Research is being conducted to develop an integrated technology for the prediction of aging behavior for space structural materials during service. This research will utilize state-of-the-art radiation experimental apparatus and analysis, updated codes and databases, and integrated mechanical and radiation testing techniques to investigate the suitability of numerous current and potential spacecraft structural materials. Also included are the effects on structural materials in surface modules and planetary landing craft, with or without fission power supplies. Spacecraft structural materials would also be in hostile radiation environments on the surface of the moon and planets without appreciable atmospheres and moons around planets with large intense magnetic and radiation fields (such as the Jovian moons). The effects of extreme temperature cycles in such locations compounds the effects of radiation on structural materials. This paper describes the integrated methodology in detail and shows that it will provide a significant technological advance for designing advanced spacecraft. This methodology will also allow for the development of advanced spacecraft materials through the understanding of the underlying mechanisms of material degradation in the space radiation environment. Thus, this technology holds a promise for revolutionary advances in material damage prediction and protection of space structural components as, for example, in the development of guidelines for managing surveillance programs regarding the integrity of spacecraft components, and the safety of the aging spacecraft. (authors)

Stay in the Box! Embedded Assistive Technology Improves Access for Students with Disabilities

Directory of Open Access Journals (Sweden)

Katherine Koch

2017-11-01

Full Text Available Assistive technology is not only a required component of a student’s IEP; it can be an effective way to help students with (and without disabilities access their education and to provide them with required instructional accommodations. Teachers, however, are often not adequately prepared in their pre-service course work and ongoing professional development to address the technology needs of their special education students and have not had the opportunities to access technology due to limited availability and cost. While assistive technology can be purchased to augment an existing computer, it is often unnecessary to do that. Both Microsoft and Apple operating systems in “off-the-shelf” computers and handheld devices have embedded assistive technology that is easy to access and easy to use. This embedded technology can help teachers become familiar with technology and assist students with sensory, physical, learning, and attention disabilities, and it might have practical applications with Universal Design for Learning. This paper provides a discussion on how embedded technology can support students with disabilities in the school setting and provides examples for access and use.

Development of embedded real-time and high-speed vision platform

Science.gov (United States)

Ouyang, Zhenxing; Dong, Yimin; Yang, Hua

2015-12-01

Currently, high-speed vision platforms are widely used in many applications, such as robotics and automation industry. However, a personal computer (PC) whose over-large size is not suitable and applicable in compact systems is an indispensable component for human-computer interaction in traditional high-speed vision platforms. Therefore, this paper develops an embedded real-time and high-speed vision platform, ER-HVP Vision which is able to work completely out of PC. In this new platform, an embedded CPU-based board is designed as substitution for PC and a DSP and FPGA board is developed for implementing image parallel algorithms in FPGA and image sequential algorithms in DSP. Hence, the capability of ER-HVP Vision with size of 320mm x 250mm x 87mm can be presented in more compact condition. Experimental results are also given to indicate that the real-time detection and counting of the moving target at a frame rate of 200 fps at 512 x 512 pixels under the operation of this newly developed vision platform are feasible.

Design of massively parallel hardware multi-processors for highly-demanding embedded applications

NARCIS (Netherlands)

Jozwiak, L.; Jan, Y.

2013-01-01

Many new embedded applications require complex computations to be performed to tight schedules, while at the same time demanding low energy consumption and low cost. For implementation of these highly-demanding applications, highly-optimized application-specific multi-processor system-on-a-chip

Design and implement of pack filter module base on embedded firewall

Science.gov (United States)

Tian, Libo; Wang, Chen; Yang, Shunbo

2011-10-01

In the traditional security solution conditions, software firewall cannot intercept and respond the invasion before being attacked. And because of the high cost, the hardware firewall does not apply to the security strategy of the end nodes, so we have designed a kind of solution of embedded firewall with hardware and software. With ARM embedding Linux operating system, we have designed packet filter module and intrusion detection module to implement the basic function of firewall. Experiments and results show that that firewall has the advantages of low cost, high processing speed, high safety and the application of the computer terminals. This paper focuses on packet filtering module design and implementation.

Design of remote weather monitor system based on embedded web database

International Nuclear Information System (INIS)

Gao Jiugang; Zhuang Along

2010-01-01

The remote weather monitoring system is designed by employing the embedded Web database technology and the S3C2410 microprocessor as the core. The monitoring system can simultaneously monitor the multi-channel sensor signals, and can give a dynamic Web pages display of various types of meteorological information on the remote computer. It gives a elaborated introduction of the construction and application of the Web database under the embedded Linux. Test results show that the client access the Web page via the GPRS or the Internet, acquires data and uses an intuitive graphical way to display the value of various types of meteorological information. (authors)

Vibration and Acoustic Testing for Mars Micromission Spacecraft

Science.gov (United States)

Kern, Dennis L.; Scharton, Terry D.

1999-01-01

The objective of the Mars Micromission program being managed by the Jet Propulsion Laboratory (JPL) for NASA is to develop a common spacecraft that can carry telecommunications equipment and a variety of science payloads for exploration of Mars. The spacecraft will be capable of carrying robot landers and rovers, cameras, probes, balloons, gliders or aircraft, and telecommunications equipment to Mars at much lower cost than recent NASA Mars missions. The lightweight spacecraft (about 220 Kg mass) will be launched in a cooperative venture with CNES as a TWIN auxiliary payload on the Ariane 5 launch vehicle. Two or more Mars Micromission launches are planned for each Mars launch opportunity, which occur every 26 months. The Mars launch window for the first mission is November 1, 2002 through April 2003, which is planned to be a Mars airplane technology demonstration mission to coincide with the 100 year anniversary of the Kittyhawk flight. Several subsequent launches will create a telecommunications network orbiting Mars, which will provide for continuous communication with lenders and rovers on the Martian surface. Dedicated science payload flights to Mars are slated to start in 2005. This new cheaper and faster approach to Mars exploration calls for innovative approaches to the qualification of the Mars Micromission spacecraft for the Ariane 5 launch vibration and acoustic environments. JPL has in recent years implemented new approaches to spacecraft testing that may be effectively applied to the Mars Micromission. These include 1) force limited vibration testing, 2) combined loads, vibration and modal testing, and 3) direct acoustic testing. JPL has performed nearly 200 force limited vibration tests in the past 9 years; several of the tests were on spacecraft and large instruments, including the Cassini and Deep Space One spacecraft. Force limiting, which measures and limits the spacecraft base reaction force using triaxial force gages sandwiched between the

Foot Pedals for Spacecraft Manual Control

Science.gov (United States)

Love, Stanley G.; Morin, Lee M.; McCabe, Mary

2010-01-01

Fifty years ago, NASA decided that the cockpit controls in spacecraft should be like the ones in airplanes. But controls based on the stick and rudder may not be best way to manually control a vehicle in space. A different method is based on submersible vehicles controlled with foot pedals. A new pilot can learn the sub's control scheme in minutes and drive it hands-free. We are building a pair of foot pedals for spacecraft control, and will test them in a spacecraft flight simulator.

Embedded software verification and debugging

CERN Document Server

Winterholer, Markus

2017-01-01

This book provides comprehensive coverage of verification and debugging techniques for embedded software, which is frequently used in safety critical applications (e.g., automotive), where failures are unacceptable. Since the verification of complex systems needs to encompass the verification of both hardware and embedded software modules, this book focuses on verification and debugging approaches for embedded software with hardware dependencies. Coverage includes the entire flow of design, verification and debugging of embedded software and all key approaches to debugging, dynamic, static, and hybrid verification. This book discusses the current, industrial embedded software verification flow, as well as emerging trends with focus on formal and hybrid verification and debugging approaches. Includes in a single source the entire flow of design, verification and debugging of embedded software; Addresses the main techniques that are currently being used in the industry for assuring the quality of embedded softw...

Isometric embeddings of 2-spheres by embedding flow for applications in numerical relativity

International Nuclear Information System (INIS)

Jasiulek, Michael; Korzyński, Mikołaj

2012-01-01

We present a numerical method for solving Weyl's embedding problem which consists in finding a global isometric embedding of a positively curved and positive-definite spherical 2-metric into the Euclidean 3-space. The method is based on a construction introduced by Weingarten and was used in Nirenberg's proof of Weyl's conjecture. The target embedding results as the endpoint of an embedding flow in R 3 beginning at the unit sphere's embedding. We employ spectral methods to handle functions on the surface and to solve various (non)linear elliptic PDEs. The code requires no additional input or steering from the operator and its convergence is guaranteed by the Nirenberg arguments. Possible applications in 3 + 1 numerical relativity range from quasi-local mass and momentum measures to coarse-graining in inhomogeneous cosmological models. (paper)

Spacecraft Thermal Management

Science.gov (United States)

Hurlbert, Kathryn Miller

2009-01-01

In the 21st century, the National Aeronautics and Space Administration (NASA), the Russian Federal Space Agency, the National Space Agency of Ukraine, the China National Space Administration, and many other organizations representing spacefaring nations shall continue or newly implement robust space programs. Additionally, business corporations are pursuing commercialization of space for enabling space tourism and capital business ventures. Future space missions are likely to include orbiting satellites, orbiting platforms, space stations, interplanetary vehicles, planetary surface missions, and planetary research probes. Many of these missions will include humans to conduct research for scientific and terrestrial benefits and for space tourism, and this century will therefore establish a permanent human presence beyond Earth s confines. Other missions will not include humans, but will be autonomous (e.g., satellites, robotic exploration), and will also serve to support the goals of exploring space and providing benefits to Earth s populace. This section focuses on thermal management systems for human space exploration, although the guiding principles can be applied to unmanned space vehicles as well. All spacecraft require a thermal management system to maintain a tolerable thermal environment for the spacecraft crew and/or equipment. The requirements for human rating and the specified controlled temperature range (approximately 275 K - 310 K) for crewed spacecraft are unique, and key design criteria stem from overall vehicle and operational/programatic considerations. These criteria include high reliability, low mass, minimal power requirements, low development and operational costs, and high confidence for mission success and safety. This section describes the four major subsystems for crewed spacecraft thermal management systems, and design considerations for each. Additionally, some examples of specialized or advanced thermal system technologies are presented

Nested Interrupt Analysis of Low Cost and High Performance Embedded Systems Using GSPN Framework

Science.gov (United States)

Lin, Cheng-Min

Interrupt service routines are a key technology for embedded systems. In this paper, we introduce the standard approach for using Generalized Stochastic Petri Nets (GSPNs) as a high-level model for generating CTMC Continuous-Time Markov Chains (CTMCs) and then use Markov Reward Models (MRMs) to compute the performance for embedded systems. This framework is employed to analyze two embedded controllers with low cost and high performance, ARM7 and Cortex-M3. Cortex-M3 is designed with a tail-chaining mechanism to improve the performance of ARM7 when a nested interrupt occurs on an embedded controller. The Platform Independent Petri net Editor 2 (PIPE2) tool is used to model and evaluate the controllers in terms of power consumption and interrupt overhead performance. Using numerical results, in spite of the power consumption or interrupt overhead, Cortex-M3 performs better than ARM7.

3D ion-scale dynamics of BBFs and their associated emissions in Earth's magnetotail using 3D hybrid simulations and MMS multi-spacecraft observations

Science.gov (United States)

Breuillard, H.; Aunai, N.; Le Contel, O.; Catapano, F.; Alexandrova, A.; Retino, A.; Cozzani, G.; Gershman, D. J.; Giles, B. L.; Khotyaintsev, Y. V.; Lindqvist, P. A.; Ergun, R.; Strangeway, R. J.; Russell, C. T.; Magnes, W.; Plaschke, F.; Nakamura, R.; Fuselier, S. A.; Turner, D. L.; Schwartz, S. J.; Torbert, R. B.; Burch, J.

2017-12-01

Transient and localized jets of hot plasma, also known as Bursty Bulk Flows (BBFs), play a crucial role in Earth's magnetotail dynamics because the energy input from the solar wind is partly dissipated in their vicinity, notably in their embedded dipolarization front (DF). This dissipation is in the form of strong low-frequency waves that can heat and accelerate energetic particles up to the high-latitude plasma sheet. The ion-scale dynamics of BBFs have been revealed by the Cluster and THEMIS multi-spacecraft missions. However, the dynamics of BBF propagation in the magnetotail are still under debate due to instrumental limitations and spacecraft separation distances, as well as simulation limitations. The NASA/MMS fleet, which features unprecedented high time resolution instruments and four spacecraft separated by kinetic-scale distances, has also shown recently that the DF normal dynamics and its associated emissions are below the ion gyroradius scale in this region. Large variations in the dawn-dusk direction were also observed. However, most of large-scale simulations are using the MHD approach and are assumed 2D in the XZ plane. Thus, in this study we take advantage of both multi-spacecraft observations by MMS and large-scale 3D hybrid simulations to investigate the 3D dynamics of BBFs and their associated emissions at ion-scale in Earth's magnetotail, and their impact on particle heating and acceleration.

Modelling the reflective thermal contribution to the acceleration of the Pioneer spacecraft

International Nuclear Information System (INIS)

Francisco, F.; Bertolami, O.; Gil, P.J.S.; Páramos, J.

2012-01-01

We present an improved method to compute the radiative momentum transfer in the Pioneer 10 and 11 spacecraft that takes into account both diffusive and specular reflection. The method allows for more reliable results regarding the thermal acceleration of the deep-space probes, confirming previous findings. A parametric analysis is performed in order to set upper and lower bounds for the thermal acceleration and its evolution with time.

Modelling the reflective thermal contribution to the acceleration of the Pioneer spacecraft

Energy Technology Data Exchange (ETDEWEB)

Francisco, F., E-mail: frederico.francisco@ist.utl.pt [Instituto de Plasmas e Fusao Nuclear, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Bertolami, O., E-mail: orfeu.bertolami@fc.up.pt [Departamento de Fisica e Astronomia, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre 687, 4169-007 Porto (Portugal); Instituto de Plasmas e Fusao Nuclear, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Gil, P.J.S., E-mail: p.gil@dem.ist.utl.pt [Departamento de Engenharia Mecanica and IDMEC - Instituto de Engenharia Mecanica, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal); Paramos, J., E-mail: paramos@ist.edu [Instituto de Plasmas e Fusao Nuclear, Instituto Superior Tecnico, Universidade Tecnica de Lisboa, Av. Rovisco Pais 1, 1049-001 Lisboa (Portugal)

2012-05-23

We present an improved method to compute the radiative momentum transfer in the Pioneer 10 and 11 spacecraft that takes into account both diffusive and specular reflection. The method allows for more reliable results regarding the thermal acceleration of the deep-space probes, confirming previous findings. A parametric analysis is performed in order to set upper and lower bounds for the thermal acceleration and its evolution with time.

Influence of the Ambient Electric Field on Measurements of the Actively Controlled Spacecraft Potential by MMS

Science.gov (United States)

Torkar, K.; Nakamura, R.; Andriopoulou, M.; Giles, B. L.; Jeszenszky, H.; Khotyaintsev, Y. V.; Lindqvist, P.-A.; Torbert, R. B.

2017-12-01

Space missions with sophisticated plasma instrumentation such as Magnetospheric Multiscale, which employs four satellites to explore near-Earth space benefit from a low electric potential of the spacecraft, to improve the plasma measurements and therefore carry instruments to actively control the potential by means of ion beams. Without control, the potential varies in anticorrelation with plasma density and temperature to maintain an equilibrium between the plasma current and the one of photoelectrons produced at the surface and overcoming the potential barrier. A drawback of the controlled, almost constant potential is the difficulty to use it as convenient estimator for plasma density. This paper identifies a correlation between the spacecraft potential and the ambient electric field, both measured by double probes mounted at the end of wire booms, as the main responsible for artifacts in the potential data besides the known effect of the variable photoelectron production due to changing illumination of the surface. It is shown that the effect of density variations is too weak to explain the observed correlation with the electric field and that a correction of the artifacts can be achieved to enable the reconstruction of the uncontrolled potential and plasma density in turn. Two possible mechanisms are discussed: the asymmetry of the current-voltage characteristic determining the probe to plasma potential and the fact that a large equipotential structure embedded in an electric field results in asymmetries of both the emission and spatial distribution of photoelectrons, which results in an increase of the spacecraft potential.

Virtual Network Embedding via Monte Carlo Tree Search.

Science.gov (United States)

Haeri, Soroush; Trajkovic, Ljiljana

2018-02-01

Network virtualization helps overcome shortcomings of the current Internet architecture. The virtualized network architecture enables coexistence of multiple virtual networks (VNs) on an existing physical infrastructure. VN embedding (VNE) problem, which deals with the embedding of VN components onto a physical network, is known to be -hard. In this paper, we propose two VNE algorithms: MaVEn-M and MaVEn-S. MaVEn-M employs the multicommodity flow algorithm for virtual link mapping while MaVEn-S uses the shortest-path algorithm. They formalize the virtual node mapping problem by using the Markov decision process (MDP) framework and devise action policies (node mappings) for the proposed MDP using the Monte Carlo tree search algorithm. Service providers may adjust the execution time of the MaVEn algorithms based on the traffic load of VN requests. The objective of the algorithms is to maximize the profit of infrastructure providers. We develop a discrete event VNE simulator to implement and evaluate performance of MaVEn-M, MaVEn-S, and several recently proposed VNE algorithms. We introduce profitability as a new performance metric that captures both acceptance and revenue to cost ratios. Simulation results show that the proposed algorithms find more profitable solutions than the existing algorithms. Given additional computation time, they further improve embedding solutions.

Standardizing the information architecture for spacecraft operations

Science.gov (United States)

Easton, C. R.

1994-01-01

This paper presents an information architecture developed for the Space Station Freedom as a model from which to derive an information architecture standard for advanced spacecraft. The information architecture provides a way of making information available across a program, and among programs, assuming that the information will be in a variety of local formats, structures and representations. It provides a format that can be expanded to define all of the physical and logical elements that make up a program, add definitions as required, and import definitions from prior programs to a new program. It allows a spacecraft and its control center to work in different representations and formats, with the potential for supporting existing spacecraft from new control centers. It supports a common view of data and control of all spacecraft, regardless of their own internal view of their data and control characteristics, and of their communications standards, protocols and formats. This information architecture is central to standardizing spacecraft operations, in that it provides a basis for information transfer and translation, such that diverse spacecraft can be monitored and controlled in a common way.

Reconfigurable computing the theory and practice of FPGA-based computation

CERN Document Server

Hauck, Scott

2010-01-01

Reconfigurable Computing marks a revolutionary and hot topic that bridges the gap between the separate worlds of hardware and software design- the key feature of reconfigurable computing is its groundbreaking ability to perform computations in hardware to increase performance while retaining the flexibility of a software solution. Reconfigurable computers serve as affordable, fast, and accurate tools for developing designs ranging from single chip architectures to multi-chip and embedded systems. Scott Hauck and Andre DeHon have assembled a group of the key experts in the fields of both hardwa

Moving Object Detection in Heterogeneous Conditions in Embedded Systems.

Science.gov (United States)

Garbo, Alessandro; Quer, Stefano

2017-07-01

This paper presents a system for moving object exposure, focusing on pedestrian detection, in external, unfriendly, and heterogeneous environments. The system manipulates and accurately merges information coming from subsequent video frames, making small computational efforts in each single frame. Its main characterizing feature is to combine several well-known movement detection and tracking techniques, and to orchestrate them in a smart way to obtain good results in diversified scenarios. It uses dynamically adjusted thresholds to characterize different regions of interest, and it also adopts techniques to efficiently track movements, and detect and correct false positives. Accuracy and reliability mainly depend on the overall receipt, i.e., on how the software system is designed and implemented, on how the different algorithmic phases communicate information and collaborate with each other, and on how concurrency is organized. The application is specifically designed to work with inexpensive hardware devices, such as off-the-shelf video cameras and small embedded computational units, eventually forming an intelligent urban grid. As a matter of fact, the major contribution of the paper is the presentation of a tool for real-time applications in embedded devices with finite computational (time and memory) resources. We run experimental results on several video sequences (both home-made and publicly available), showing the robustness and accuracy of the overall detection strategy. Comparisons with state-of-the-art strategies show that our application has similar tracking accuracy but much higher frame-per-second rates.

Planning and Building Qualifiable Embedded Systems: Safety and Risk Properties Assessment for a Large and Complex System with Embedded Subsystems

Science.gov (United States)

Silva, N.; Lopes, R.; Barbosa, R.

2012-01-01

Systems based on embedded components and applications are today used in all markets. They are planned and developed by all types of institutions with different types of background experience, multidisciplinary teams and all types of capability and maturity levels. Organisational/engineering maturity has an impact on all aspects of the engineering of large and complex systems. An embedded system is a specific computer system designed to perform one or more dedicated functions, usually with real-time constraints. It is generally integrated as part of a more complex device typically composed of specific hardware such as sensors and actuators. This article presents an experimented technique to evaluate the organisation, processes, system and software engineering practices, methods, tools and the planned/produced artefacts themselves, leading towards certification/qualification. The safety and risk assessment of such core and complex systems is explained, described on a step-by- step manner, while presenting the main results and conclusions of the application of the technique to a real case study.

Passive Plasma Contact Mechanisms for Small-Scale Spacecraft

Science.gov (United States)

McTernan, Jesse K.

Small-scale spacecraft represent a paradigm shift in how entities such as academia, industry, engineering firms, and the scientific community operate in space. However, although the paradigm shift produces unique opportunities to build satellites in unique ways for novel missions, there are also significant challenges that must be addressed. This research addresses two of the challenges associated with small-scale spacecraft: 1) the miniaturization of spacecraft and associated instrumentation and 2) the need to transport charge across the spacecraft-environment boundary. As spacecraft decrease in size, constraints on the size, weight, and power of on-board instrumentation increase--potentially limiting the instrument's functionality or ability to integrate with the spacecraft. These constraints drive research into mechanisms or techniques that use little or no power and efficiently utilize existing resources. One limited resource on small-scale spacecraft is outer surface area, which is often covered with solar panels to meet tight power budgets. This same surface area could also be needed for passive neutralization of spacecraft charging. This research explores the use of a transparent, conductive layer on the solar cell coverglass that is electrically connected to spacecraft ground potential. This dual-purpose material facilitates the use of outer surfaces for both energy harvesting of solar photons as well as passive ion collection. Mission capabilities such as in-situ plasma measurements that were previously infeasible on small-scale platforms become feasible with the use of indium tin oxide-coated solar panel coverglass. We developed test facilities that simulate the space environment in low Earth orbit to test the dual-purpose material and the various application of this approach. Particularly, this research is in support of two upcoming missions: OSIRIS-3U, by Penn State's Student Space Programs Lab, and MiTEE, by the University of Michigan. The purpose of

COMPUTERS IN SURGERY

African Journals Online (AJOL)

BODE

Key words: Computers, surgery, applications. Introduction ... With improved memory, speed and processing power in an ever more compact ... with picture and voice embedment to wit. With the ... recall the tedium of anatomy, physiology and.

Trajectory Control of Rendezvous with Maneuver Target Spacecraft

Science.gov (United States)

Zhou, Zhinqiang

2012-01-01

In this paper, a nonlinear trajectory control algorithm of rendezvous with maneuvering target spacecraft is presented. The disturbance forces on the chaser and target spacecraft and the thrust forces on the chaser spacecraft are considered in the analysis. The control algorithm developed in this paper uses the relative distance and relative velocity between the target and chaser spacecraft as the inputs. A general formula of reference relative trajectory of the chaser spacecraft to the target spacecraft is developed and applied to four different proximity maneuvers, which are in-track circling, cross-track circling, in-track spiral rendezvous and cross-track spiral rendezvous. The closed-loop differential equations of the proximity relative motion with the control algorithm are derived. It is proven in the paper that the tracking errors between the commanded relative trajectory and the actual relative trajectory are bounded within a constant region determined by the control gains. The prediction of the tracking errors is obtained. Design examples are provided to show the implementation of the control algorithm. The simulation results show that the actual relative trajectory tracks the commanded relative trajectory tightly. The predicted tracking errors match those calculated in the simulation results. The control algorithm developed in this paper can also be applied to interception of maneuver target spacecraft and relative trajectory control of spacecraft formation flying.

Spacecraft command and control using expert systems

Science.gov (United States)

Norcross, Scott; Grieser, William H.

1994-01-01

This paper describes a product called the Intelligent Mission Toolkit (IMT), which was created to meet the changing demands of the spacecraft command and control market. IMT is a command and control system built upon an expert system. Its primary functions are to send commands to the spacecraft and process telemetry data received from the spacecraft. It also controls the ground equipment used to support the system, such as encryption gear, and telemetry front-end equipment. Add-on modules allow IMT to control antennas and antenna interface equipment. The design philosophy for IMT is to utilize available commercial products wherever possible. IMT utilizes Gensym's G2 Real-time Expert System as the core of the system. G2 is responsible for overall system control, spacecraft commanding control, and spacecraft telemetry analysis and display. Other commercial products incorporated into IMT include the SYBASE relational database management system and Loral Test and Integration Systems' System 500 for telemetry front-end processing.

The embedded operating system project

Science.gov (United States)

Campbell, R. H.

1985-01-01

The design and construction of embedded operating systems for real-time advanced aerospace applications was investigated. The applications require reliable operating system support that must accommodate computer networks. Problems that arise in the construction of such operating systems, reconfiguration, consistency and recovery in a distributed system, and the issues of real-time processing are reported. A thesis that provides theoretical foundations for the use of atomic actions to support fault tolerance and data consistency in real-time object-based system is included. The following items are addressed: (1) atomic actions and fault-tolerance issues; (2) operating system structure; (3) program development; (4) a reliable compiler for path Pascal; and (5) mediators, a mechanism for scheduling distributed system processes.

Artist concept of Galileo spacecraft

Science.gov (United States)

1988-01-01

Galileo spacecraft is illustrated in artist concept. Gallileo, named for the Italian astronomer, physicist and mathematician who is credited with construction of the first complete, practical telescope in 1620, will make detailed studies of Jupiter. A cooperative program with the Federal Republic of Germany the Galileo mission will amplify information acquired by two Voyager spacecraft in their brief flybys. Galileo is a two-element system that includes a Jupiter-orbiting observatory and an entry probe. Jet Propulsion Laboratory (JPL) is Galileo project manager and builder of the main spacecraft. Ames Research Center (ARC) has responsibility for the entry probe, which was built by Hughes Aircraft Company and General Electric. Galileo will be deployed from the payload bay (PLB) of Atlantis, Orbiter Vehicle (OV) 104, during mission STS-34.

A 3-D chimera grid embedding technique

Science.gov (United States)

Benek, J. A.; Buning, P. G.; Steger, J. L.

1985-01-01

A three-dimensional (3-D) chimera grid-embedding technique is described. The technique simplifies the construction of computational grids about complex geometries. The method subdivides the physical domain into regions which can accommodate easily generated grids. Communication among the grids is accomplished by interpolation of the dependent variables at grid boundaries. The procedures for constructing the composite mesh and the associated data structures are described. The method is demonstrated by solution of the Euler equations for the transonic flow about a wing/body, wing/body/tail, and a configuration of three ellipsoidal bodies.

Coupling dynamic analysis of spacecraft with multiple cylindrical tanks and flexible appendages

Science.gov (United States)

Wu, Wen-Jun; Yue, Bao-Zeng; Huang, Hua

2016-02-01

This paper is mainly concerned with the coupling dynamic analysis of a complex spacecraft consisting of one main rigid platform, multiple liquid-filled cylindrical tanks, and a number of flexible appendages. Firstly, the carrier potential function equations of liquid in the tanks are deduced according to the wall boundary conditions. Through employing the Fourier-Bessel series expansion method, the dynamic boundaries conditions on a curved free-surface under a low-gravity environment are transformed to general simple differential equations and the rigid-liquid coupled sloshing dynamic state equations of liquid in tanks are obtained. The state vectors of rigid-liquid coupled equations are composed with the modal coordinates of the relative potential function and the modal coordinates of wave height. Based on the Bernoulli-Euler beam theory and the D'Alembert's principle, the rigid-flexible coupled dynamic state equations of flexible appendages are directly derived, and the coordinate transform matrixes of maneuvering flexible appendages are precisely computed as time-varying. Then, the coupling dynamics state equations of the overall system of the spacecraft are modularly built by means of the Lagrange's equations in terms of quasi-coordinates. Lastly, the coupling dynamic performances of a typical complex spacecraft are studied. The availability and reliability of the presented method are also confirmed.

Addressing EO-1 Spacecraft Pulsed Plasma Thruster EMI Concerns

Science.gov (United States)

Zakrzwski, C. M.; Davis, Mitch; Sarmiento, Charles; Bauer, Frank H. (Technical Monitor)

2001-01-01

The Pulsed Plasma Thruster (PPT) Experiment on the Earth Observing One (EO-1) spacecraft has been designed to demonstrate the capability of a new generation PPT to perform spacecraft attitude control. Results from PPT unit level radiated electromagnetic interference (EMI) tests led to concerns about potential interference problems with other spacecraft subsystems. Initial plans to address these concerns included firing the PPT at the spacecraft level both in atmosphere, with special ground support equipment. and in vacuum. During the spacecraft level tests, additional concerns where raised about potential harm to the Advanced Land Imager (ALI). The inadequacy of standard radiated emission test protocol to address pulsed electromagnetic discharges and the lack of resources required to perform compatibility tests between the PPT and an ALI test unit led to changes in the spacecraft level validation plan. An EMI shield box for the PPT was constructed and validated for spacecraft level ambient testing. Spacecraft level vacuum tests of the PPT were deleted. Implementation of the shield box allowed for successful spacecraft level testing of the PPT while eliminating any risk to the ALI. The ALI demonstration will precede the PPT demonstration to eliminate any possible risk of damage of ALI from PPT operation.

Thermal radiators with embedded pulsating heat pipes: Infra-red thermography and simulations

International Nuclear Information System (INIS)

Hemadri, Vadiraj A.; Gupta, Ashish; Khandekar, Sameer

2011-01-01

With the aim of exploring potential applications of Pulsating Heat Pipes (PHP), for space/terrestrial sectors, experimental study of embedded PHP thermal radiators, having two different effective Biot numbers respectively, and subjected to conjugate heat transfer conditions on their surface, i.e., natural convection and radiation, has been carried out under different thermo-mechanical boundary conditions. High resolution infrared camera is used to obtain spatial temperature profiles of the radiators. To complement the experimental study, detailed 3D computational heat transfer simulation has also been undertaken. By embedding PHP structures, it was possible to make the net thermal resistance of the mild steel radiator plate equivalent to the aluminum radiator plate, in spite of the large difference in their respective thermal conductivities (k Al ∼ 4k MS ). The study reveals that embedded PHP structures can be beneficial only under certain boundary conditions. The degree of isothermalization achieved in these structures strongly depends on its effective Biot number. The relative advantage of embedded PHP is appreciably higher if the thermal conductivity of the radiator plate material itself is low. The study indicates that the effective thermal conductivity of embedded PHP structure is of the order of 400 W/mK to 2300 W/mK, depending on the operating conditions. - Research highlights: → Study of radiator plates with embedded Pulsating Heat Pipe by infrared thermography. → Radiator is subjected to natural convection and radiation boundary conditions. → Experimental study is supported by 3D simulation. → Effective thermal conductivity of PHPs of the order of 2000 W/mK is obtained. → Efficacy of embedded PHPs depends on the effective Biot number of the system.

How Spacecraft Fly Spaceflight Without Formulae

CERN Document Server

Swinerd, Graham

2009-01-01

About half a century ago a small satellite, Sputnik 1, was launched. The satellite did very little other than to transmit a radio signal to announce its presence in orbit. However, this humble beginning heralded the dawn of the Space Age. Today literally thousands of robotic spacecraft have been launched, many of which have flown to far-flung regions of the Solar System carrying with them the human spirit of scientific discovery and exploration. Numerous other satellites have been launched in orbit around the Earth providing services that support our technological society on the ground. How Spacecraft Fly: Spaceflight Without Formulae by Graham Swinerd focuses on how these spacecraft work. The book opens with a historical perspective of how we have come to understand our Solar System and the Universe. It then progresses through orbital flight, rocket science, the hostile environment within which spacecraft operate, and how they are designed. The concluding chapters give a glimpse of what the 21st century may ...

Optimal Autonomous Spacecraft Resiliency Maneuvers Using Metaheuristics

Science.gov (United States)

2014-09-15

This work was accepted for published by the American Institute of Aeronautics and Astronautics (AIAA) Journal of Spacecraft and Rockets in July 2014...publication in the AIAA Journal of Spacecraft and Rockets . Chapter 5 introduces an impulsive maneuvering strategy to deliver a spacecraft to its final...upon arrival r2 and v2 , respectively. The variable T2 determines the time of flight needed to make the maneuver, and the variable θ2 determines the

Integrating standard operating procedures with spacecraft automation, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Spacecraft automation has the potential to assist crew members and spacecraft operators in managing spacecraft systems during extended space missions. Automation can...

Improving developer productivity with C++ embedded domain specific languages

Science.gov (United States)

Kozacik, Stephen; Chao, Evenie; Paolini, Aaron; Bonnett, James; Kelmelis, Eric

2017-05-01

Domain-specific languages are a useful tool for productivity allowing domain experts to program using familiar concepts and vocabulary while benefiting from performance choices made by computing experts. Embedding the domain specific language into an existing language allows easy interoperability with non-domain-specific code and use of standard compilers and build systems. In C++, this is enabled through the template and preprocessor features. C++ embedded domain specific languages (EDSLs) allow the user to write simple, safe, performant, domain specific code that has access to all the low-level functionality that C and C++ offer as well as the diverse set of libraries available in the C/C++ ecosystem. In this paper, we will discuss several tools available for building EDSLs in C++ and show examples of projects successfully leveraging EDSLs. Modern C++ has added many useful new features to the language which we have leveraged to further extend the capability of EDSLs. At EM Photonics, we have used EDSLs to allow developers to transparently benefit from using high performance computing (HPC) hardware. We will show ways EDSLs combine with existing technologies and EM Photonics high performance tools and libraries to produce clean, short, high performance code in ways that were not previously possible.

An Information Technology Framework for the Development of an Embedded Computer System for the Remote and Non-Destructive Study of Sensitive Archaeology Sites

Directory of Open Access Journals (Sweden)

Iliya Georgiev

2017-04-01

Full Text Available The paper proposes an information technology framework for the development of an embedded remote system for non-destructive observation and study of sensitive archaeological sites. The overall concept and motivation are described. The general hardware layout and software configuration are presented. The paper concentrates on the implementation of the following informational technology components: (a a geographically unique identification scheme supporting a global key space for a key-value store; (b a common method for octree modeling for spatial geometrical models of the archaeological artifacts, and abstract object representation in the global key space; (c a broadcast of the archaeological information as an Extensible Markup Language (XML stream over the Web for worldwide availability; and (d a set of testing methods increasing the fault tolerance of the system. This framework can serve as a foundation for the development of a complete system for remote archaeological exploration of enclosed archaeological sites like buried churches, tombs, and caves. An archaeological site is opened once upon discovery, the embedded computer system is installed inside upon a robotic platform, equipped with sensors, cameras, and actuators, and the intact site is sealed again. Archaeological research is conducted on a multimedia data stream which is sent remotely from the system and conforms to necessary standards for digital archaeology.

Quick Spacecraft Thermal Analysis Tool, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — For spacecraft design and development teams concerned with cost and schedule, the Quick Spacecraft Thermal Analysis Tool (QuickSTAT) is an innovative software suite...

Embedding Complementarity in HCI Methods

DEFF Research Database (Denmark)

Nielsen, Janni; Yssing, Carsten; Tweddell Levinsen, Karin

2007-01-01

Differences in cultural contexts constitute differences in cognition, and research has shown that different cultures may use different cognitive tools for perception and reasoning. The cultural embeddings are significant in relation to HCI, because the cultural context is also embedded in the tec......Differences in cultural contexts constitute differences in cognition, and research has shown that different cultures may use different cognitive tools for perception and reasoning. The cultural embeddings are significant in relation to HCI, because the cultural context is also embedded...

Smart Multicore Embedded Systems

DEFF Research Database (Denmark)

This book provides a single-source reference to the state-of-the-art of high-level programming models and compilation tool-chains for embedded system platforms. The authors address challenges faced by programmers developing software to implement parallel applications in embedded systems, where very...... specificities of various embedded systems from different industries. Parallel programming tool-chains are described that take as input parameters both the application and the platform model, then determine relevant transformations and mapping decisions on the concrete platform, minimizing user intervention...... and hiding the difficulties related to the correct and efficient use of memory hierarchy and low level code generation. Describes tools and programming models for multicore embedded systems Emphasizes throughout performance per watt scalability Discusses realistic limits of software parallelization Enables...

Revamping Spacecraft Operational Intelligence

Science.gov (United States)

Hwang, Victor

2012-01-01

The EPOXI flight mission has been testing a new commercial system, Splunk, which employs data mining techniques to organize and present spacecraft telemetry data in a high-level manner. By abstracting away data-source specific details, Splunk unifies arbitrary data formats into one uniform system. This not only reduces the time and effort for retrieving relevant data, but it also increases operational visibility by allowing a spacecraft team to correlate data across many different sources. Splunk's scalable architecture coupled with its graphing modules also provide a solid toolset for generating data visualizations and building real-time applications such as browser-based telemetry displays.

Reliability Analysis and Optimal Release Problem Considering Maintenance Time of Software Components for an Embedded OSS Porting Phase

Science.gov (United States)

Tamura, Yoshinobu; Yamada, Shigeru

OSS (open source software) systems which serve as key components of critical infrastructures in our social life are still ever-expanding now. Especially, embedded OSS systems have been gaining a lot of attention in the embedded system area, i.e., Android, BusyBox, TRON, etc. However, the poor handling of quality problem and customer support prohibit the progress of embedded OSS. Also, it is difficult for developers to assess the reliability and portability of embedded OSS on a single-board computer. In this paper, we propose a method of software reliability assessment based on flexible hazard rates for the embedded OSS. Also, we analyze actual data of software failure-occurrence time-intervals to show numerical examples of software reliability assessment for the embedded OSS. Moreover, we compare the proposed hazard rate model for the embedded OSS with the typical conventional hazard rate models by using the comparison criteria of goodness-of-fit. Furthermore, we discuss the optimal software release problem for the porting-phase based on the total expected software maintenance cost.

High-Speed Solution of Spacecraft Trajectory Problems Using Taylor Series Integration

Science.gov (United States)

Scott, James R.; Martini, Michael C.

2010-01-01

It has been known for some time that Taylor series (TS) integration is among the most efficient and accurate numerical methods in solving differential equations. However, the full benefit of the method has yet to be realized in calculating spacecraft trajectories, for two main reasons. First, most applications of Taylor series to trajectory propagation have focused on relatively simple problems of orbital motion or on specific problems and have not provided general applicability. Second, applications that have been more general have required use of a preprocessor, which inevitably imposes constraints on computational efficiency. The latter approach includes the work of Berryman et al., who solved the planetary n-body problem with relativistic effects. Their work specifically noted the computational inefficiencies arising from use of a preprocessor and pointed out the potential benefit of manually coding derivative routines. In this Engineering Note, we report on a systematic effort to directly implement Taylor series integration in an operational trajectory propagation code: the Spacecraft N-Body Analysis Program (SNAP). The present Taylor series implementation is unique in that it applies to spacecraft virtually anywhere in the solar system and can be used interchangeably with another integration method. SNAP is a high-fidelity trajectory propagator that includes force models for central body gravitation with N X N harmonics, other body gravitation with N X N harmonics, solar radiation pressure, atmospheric drag (for Earth orbits), and spacecraft thrusting (including shadowing). The governing equations are solved using an eighth-order Runge-Kutta Fehlberg (RKF) single-step method with variable step size control. In the present effort, TS is implemented by way of highly integrated subroutines that can be used interchangeably with RKF. This makes it possible to turn TS on or off during various phases of a mission. Current TS force models include central body

Robonaut 2 and Watson: Cognitive Dexterity for Future Exploration

Science.gov (United States)

Badger, Julia M.; Strawser, Philip; Farrell, Logan; Goza, S. Michael; Claunch, Charles A.; Chancey, Raphael; Potapinski, Russell

2018-01-01

Future exploration missions will dictate a level of autonomy never before experienced in human spaceflight. Mission plans involving the uncrewed phases of complex human spacecraft in deep space will require a coordinated autonomous capability to be able to maintain the spacecraft when ground control is not available. One promising direction involves embedding intelligence into the system design both through the employment of state-of-the-art system engineering principles as well as through the creation of a cognitive network between a smart spacecraft or habitat and embodiments of cognitive agents. The work described here details efforts to integrate IBM's Watson and other cognitive computing services into NASA Johnson Space Center (JSC)'s Robonaut 2 (R2) anthropomorphic robot. This paper also discusses future directions this work will take. A cognitive spacecraft management system that is able to seamlessly collect data from subsystems, determine corrective actions, and provide commands to enable those actions is the end goal. These commands could be to embedded spacecraft systems or to a set of robotic assets that are tied into the cognitive system. An exciting collaboration with Woodside provides a promising Earth-bound testing analog, as controlling and maintaining not normally manned off-shore platforms have similar constraints to the space missions described.

Design feasibility via ascent optimality for next-generation spacecraft

Science.gov (United States)

Miele, A.; Mancuso, S.

This paper deals with the optimization of the ascent trajectories for single-stage-sub-orbit (SSSO), single-stage-to-orbit (SSTO), and two-stage-to-orbit (TSTO) rocket-powered spacecraft. The maximum payload weight problem is studied for different values of the engine specific impulse and spacecraft structural factor. The main conclusions are that: feasibility of SSSO spacecraft is guaranteed for all the parameter combinations considered; feasibility of SSTO spacecraft depends strongly on the parameter combination chosen; not only feasibility of TSTO spacecraft is guaranteed for all the parameter combinations considered, but the TSTO payload is several times the SSTO payload. Improvements in engine specific impulse and spacecraft structural factor are desirable and crucial for SSTO feasibility; indeed, aerodynamic improvements do not yield significant improvements in payload. For SSSO, SSTO, and TSTO spacecraft, simple engineering approximations are developed connecting the maximum payload weight to the engine specific impulse and spacecraft structural factor. With reference to the specific impulse/structural factor domain, these engineering approximations lead to the construction of zero-payload lines separating the feasibility region (positive payload) from the unfeasibility region (negative payload).

Hybrid brain-computer interface for biomedical cyber-physical system application using wireless embedded EEG systems.

Science.gov (United States)

Chai, Rifai; Naik, Ganesh R; Ling, Sai Ho; Nguyen, Hung T

2017-01-07

One of the key challenges of the biomedical cyber-physical system is to combine cognitive neuroscience with the integration of physical systems to assist people with disabilities. Electroencephalography (EEG) has been explored as a non-invasive method of providing assistive technology by using brain electrical signals. This paper presents a unique prototype of a hybrid brain computer interface (BCI) which senses a combination classification of mental task, steady state visual evoked potential (SSVEP) and eyes closed detection using only two EEG channels. In addition, a microcontroller based head-mounted battery-operated wireless EEG sensor combined with a separate embedded system is used to enhance portability, convenience and cost effectiveness. This experiment has been conducted with five healthy participants and five patients with tetraplegia. Generally, the results show comparable classification accuracies between healthy subjects and tetraplegia patients. For the offline artificial neural network classification for the target group of patients with tetraplegia, the hybrid BCI system combines three mental tasks, three SSVEP frequencies and eyes closed, with average classification accuracy at 74% and average information transfer rate (ITR) of the system of 27 bits/min. For the real-time testing of the intentional signal on patients with tetraplegia, the average success rate of detection is 70% and the speed of detection varies from 2 to 4 s.

Embedded with Facebook: DoD Faces Risks from Social Media

Science.gov (United States)

2011-06-01

Facebook and other social network websites, and now allows them to be used from official computer systems and...appropriate conduct. Embedded with Social Media Today Facebook is the world’s dominant social network site. Facebook boasts over 600 million active users...billion minutes on the site each month [4]. Facebook is also the most popular social network site for DoD personnel. Using our techniques for

Impact of computer advances on future finite elements computations. [for aircraft and spacecraft design

Science.gov (United States)

Fulton, Robert E.

1985-01-01

Research performed over the past 10 years in engineering data base management and parallel computing is discussed, and certain opportunities for research toward the next generation of structural analysis capability are proposed. Particular attention is given to data base management associated with the IPAD project and parallel processing associated with the Finite Element Machine project, both sponsored by NASA, and a near term strategy for a distributed structural analysis capability based on relational data base management software and parallel computers for a future structural analysis system.

Communicating embedded systems networks applications

CERN Document Server

Krief, Francine

2013-01-01

Embedded systems become more and more complex and require having some knowledge in various disciplines such as electronics, data processing, telecommunications and networks. Without detailing all the aspects related to the design of embedded systems, this book, which was written by specialists in electronics, data processing and telecommunications and networks, gives an interesting point of view of communication techniques and problems in embedded systems. This choice is easily justified by the fact that embedded systems are today massively communicating and that telecommunications and network

The Role of Mythical Form of Thinking Embedded into Earlier and Recent Computer Games in Teaching Religious and Ethical Values

Directory of Open Access Journals (Sweden)

Hülya ALTUNYA

2017-08-01

Full Text Available In the world of eastern thought, narration of exemplary events is common through methods of mythical expression such as fairy tales, stories, myths etc. In these discourses, it is aimed at giving moral advice and thus educating the audience. It is stated in these discourses in which surreal events are told people who stand up against distress and difficulties retain their happiness. In such narrative texts, on one hand hope is being kept alive; on the other hand, such messages as patience, clinging to honesty under harsh times and possessing stamina are conveyed to the audience. Likewise, today, surreal events; namely, mythical fictions are animated in cartoons, animation and computer games. In these games, it is told that the most brutal battles are carried out through the most merciless weapons and only the most powerful one wins. These games, causing youth to grow up as aggressive, merciless and likely to try each way to seize power, should be examined in terms of education as well as that way of thinking. In this article, the form of thinking in the stories in which surreal events in the past were narrated is compared in terms of ethical values with the form of thinking in recent computer games in which surreal events are embedded.

Research-Based Monitoring, Prediction, and Analysis Tools of the Spacecraft Charging Environment for Spacecraft Users

Science.gov (United States)

Zheng, Yihua; Kuznetsova, Maria M.; Pulkkinen, Antti A.; Maddox, Marlo M.; Mays, Mona Leila

2015-01-01

The Space Weather Research Center (http://swrc. gsfc.nasa.gov) at NASA Goddard, part of the Community Coordinated Modeling Center (http://ccmc.gsfc.nasa.gov), is committed to providing research-based forecasts and notifications to address NASA's space weather needs, in addition to its critical role in space weather education. It provides a host of services including spacecraft anomaly resolution, historical impact analysis, real-time monitoring and forecasting, tailored space weather alerts and products, and weekly summaries and reports. In this paper, we focus on how (near) real-time data (both in space and on ground), in combination with modeling capabilities and an innovative dissemination system called the integrated Space Weather Analysis system (http://iswa.gsfc.nasa.gov), enable monitoring, analyzing, and predicting the spacecraft charging environment for spacecraft users. Relevant tools and resources are discussed.

Design Methodologies for Secure Embedded Systems

CERN Document Server

Biedermann, Alexander

2011-01-01

Embedded systems have been almost invisibly pervading our daily lives for several decades. They facilitate smooth operations in avionics, automotive electronics, or telecommunication. New problems arise by the increasing employment, interconnection, and communication of embedded systems in heterogeneous environments: How secure are these embedded systems against attacks or breakdowns? Therefore, how can embedded systems be designed to be more secure? And how can embedded systems autonomically react to threats? Facing these questions, Sorin A. Huss is significantly involved in the exploration o

Three Dimensional Simulation of Ion Thruster Plume-Spacecraft Interaction Based on a Graphic Processor Unit

International Nuclear Information System (INIS)

Ren Junxue; Xie Kan; Qiu Qian; Tang Haibin; Li Juan; Tian Huabing

2013-01-01

Based on the three-dimensional particle-in-cell (PIC) method and Compute Unified Device Architecture (CUDA), a parallel particle simulation code combined with a graphic processor unit (GPU) has been developed for the simulation of charge-exchange (CEX) xenon ions in the plume of an ion thruster. Using the proposed technique, the potential and CEX plasma distribution are calculated for the ion thruster plume surrounding the DS1 spacecraft at different thrust levels. The simulation results are in good agreement with measured CEX ion parameters reported in literature, and the GPU's results are equal to a CPU's. Compared with a single CPU Intel Core 2 E6300, 16-processor GPU NVIDIA GeForce 9400 GT indicates a speedup factor of 3.6 when the total macro particle number is 1.1×10 6 . The simulation results also reveal how the back flow CEX plasma affects the spacecraft floating potential, which indicates that the plume of the ion thruster is indeed able to alleviate the extreme negative floating potentials of spacecraft in geosynchronous orbit

Industry perspectives on Plug-& -Play Spacecraft Avionics

Science.gov (United States)

Franck, R.; Graven, P.; Liptak, L.

This paper describes the methodologies and findings from an industry survey of awareness and utility of Spacecraft Plug-& -Play Avionics (SPA). The survey was conducted via interviews, in-person and teleconference, with spacecraft prime contractors and suppliers. It focuses primarily on AFRL's SPA technology development activities but also explores the broader applicability and utility of Plug-& -Play (PnP) architectures for spacecraft. Interviews include large and small suppliers as well as large and small spacecraft prime contractors. Through these “ product marketing” interviews, awareness and attitudes can be assessed, key technical and market barriers can be identified, and opportunities for improvement can be uncovered. Although this effort focuses on a high-level assessment, similar processes can be used to develop business cases and economic models which may be necessary to support investment decisions.

Multiple spacecraft observations of interplanetary shocks: four spacecraft determination of shock normals

International Nuclear Information System (INIS)

Russell, C.T.; Mellott, M.M.; Smith, E.J.; King, J.H.

1983-01-01

ISEE 1,2,3 IMP8, and Prognoz 7 observations of interplanetary shocks in 1978 and 1979 provide five instances where a single shock is observed by four spacecraft. These observations are used to determine best-fit normals for these five shocks. In addition to providing well-documented shocks for furture techniques. When the angle between upstream and downstream magnetic field is greater than 20, magnetic coplanarity can be an accurate single spacecraft method. However, no technique based solely on the magnetic measurements at one or multiple sites was universally accurate. Thus, we recommend using overdetermined shock normal solutions whenever possible, utilizing plasma measurements, separation vectors, and time delays together with magnetic constraints

Spacecraft design project: Low Earth orbit communications satellite

Science.gov (United States)

Moroney, Dave; Lashbrook, Dave; Mckibben, Barry; Gardener, Nigel; Rivers, Thane; Nottingham, Greg; Golden, Bill; Barfield, Bill; Bruening, Joe; Wood, Dave

1991-01-01

This is the final product of the spacecraft design project completed to fulfill the academic requirements of the Spacecraft Design and Integration 2 course (AE-4871) taught at the U.S. Naval Postgraduate School. The Spacecraft Design and Integration 2 course is intended to provide students detailed design experience in selection and design of both satellite system and subsystem components, and their location and integration into a final spacecraft configuration. The design team pursued a design to support a Low Earth Orbiting (LEO) communications system (GLOBALSTAR) currently under development by the Loral Cellular Systems Corporation. Each of the 14 team members was assigned both primary and secondary duties in program management or system design. Hardware selection, spacecraft component design, analysis, and integration were accomplished within the constraints imposed by the 11 week academic schedule and the available design facilities.

A Rapid Prototyping Environment for Wireless Communication Embedded Systems

Directory of Open Access Journals (Sweden)

Bryan A. Jones

2003-05-01

Full Text Available This paper introduces a rapid prototyping methodology which overcomes important barriers in the design and implementation of digital signal processing (DSP algorithms and systems on embedded hardware platforms, such as cellular phones. This paper describes rapid prototyping in terms of a simulation/prototype bridge and in terms of appropriate language design. The simulation/prototype bridge combines the strengths of simulation and of prototyping, allowing the designer to develop and evaluate next-generation communications systems, partly in simulation on a host computer and partly as a prototype on embedded hardware. Appropriate language design allows designers to express a communications system as a block diagram, in which each block represents an algorithm specified by a set of equations. Software tools developed for this paper implement both concepts, and have been successfully used in the development of a next-generation code division multiple access (CDMA cellular wireless communications system.

Effort to recover SOHO spacecraft continue as investigation board focuses on most likely causes

Science.gov (United States)

1998-07-01

Meanwhile, the ESA/NASA investigation board concentrates its inquiry on three errors that appear to have led to the interruption of communications with SOHO on June 25. Officials remain hopeful that, based on ESA's successful recovery of the Olympus spacecraft after four weeks under similar conditions in 1991, recovery of SOHO may be possible. The SOHO Mission Interruption Joint ESA/NASA Investigation Board has determined that the first two errors were contained in preprogrammed command sequences executed on ground system computers, while the last error was a decision to send a command to the spacecraft in response to unexpected telemetry readings. The spacecraft is controlled by the Flight Operations Team, based at NASA's Goddard Space Flight Center, Greenbelt, MD. The first error was in a preprogrammed command sequence that lacked a command to enable an on-board software function designed to activate a gyro needed for control in Emergency Sun Reacquisition (ESR) mode. ESR mode is entered by the spacecraft in the event of anomalies. The second error, which was in a different preprogrammed command sequence, resulted in incorrect readings from one of the spacecraft's three gyroscopes, which in turn triggered an ESR. At the current stage of the investigation, the board believes that the two anomalous command sequences, in combination with a decision to send a command to SOHO to turn off a gyro in response to unexpected telemetry values, caused the spacecraft to enter a series of ESRs, and ultimately led to the loss of control. The efforts of the investigation board are now directed at identifying the circumstances that led to the errors, and at developing a recovery plan should efforts to regain contact with the spacecraft succeed. ESA and NASA engineers believe the spacecraft is currently spinning with its solar panels nearly edge-on towards the Sun, and thus not generating any power. Since the spacecraft is spinning around a fixed axis, as the spacecraft progresses

Developing Sustainable Spacecraft Water Management Systems

Science.gov (United States)

Thomas, Evan A.; Klaus, David M.

2009-01-01

It is well recognized that water handling systems used in a spacecraft are prone to failure caused by biofouling and mineral scaling, which can clog mechanical systems and degrade the performance of capillary-based technologies. Long duration spaceflight applications, such as extended stays at a Lunar Outpost or during a Mars transit mission, will increasingly benefit from hardware that is generally more robust and operationally sustainable overtime. This paper presents potential design and testing considerations for improving the reliability of water handling technologies for exploration spacecraft. Our application of interest is to devise a spacecraft wastewater management system wherein fouling can be accommodated by design attributes of the management hardware, rather than implementing some means of preventing its occurrence.

Relativistic Spacecraft Propelled by Directed Energy

Science.gov (United States)

Kulkarni, Neeraj; Lubin, Philip; Zhang, Qicheng

2018-04-01

Achieving relativistic flight to enable extrasolar exploration is one of the dreams of humanity and the long-term goal of our NASA Starlight program. We derive a relativistic solution for the motion of a spacecraft propelled by radiation pressure from a directed energy (DE) system. Depending on the system parameters, low-mass spacecraft can achieve relativistic speeds, thus enabling interstellar exploration. The diffraction of the DE system plays an important role and limits the maximum speed of the spacecraft. We consider “photon recycling” as a possible method to achieving higher speeds. We also discuss recent claims that our previous work on this topic is incorrect and show that these claims arise from an improper treatment of causality.

Time Frequency Analysis of Spacecraft Propellant Tank Spinning Slosh

Science.gov (United States)

Green, Steven T.; Burkey, Russell C.; Sudermann, James

2010-01-01

Many spacecraft are designed to spin about an axis along the flight path as a means of stabilizing the attitude of the spacecraft via gyroscopic stiffness. Because of the assembly requirements of the spacecraft and the launch vehicle, these spacecraft often spin about an axis corresponding to a minor moment of inertia. In such a case, any perturbation of the spin axis will cause sloshing motions in the liquid propellant tanks that will eventually dissipate enough kinetic energy to cause the spin axis nutation (wobble) to grow further. This spinning slosh and resultant nutation growth is a primary design problem of spinning spacecraft and one that is not easily solved by analysis or simulation only. Testing remains the surest way to address spacecraft nutation growth. This paper describes a test method and data analysis technique that reveal the resonant frequency and damping behavior of liquid motions in a spinning tank. Slosh resonant frequency and damping characteristics are necessary inputs to any accurate numerical dynamic simulation of the spacecraft.

Computer simulation of the NASA water vapor electrolysis reactor

Science.gov (United States)

Bloom, A. M.

1974-01-01

The water vapor electrolysis (WVE) reactor is a spacecraft waste reclamation system for extended-mission manned spacecraft. The WVE reactor's raw material is water, its product oxygen. A computer simulation of the WVE operational processes provided the data required for an optimal design of the WVE unit. The simulation process was implemented with the aid of a FORTRAN IV routine.

Dips spacecraft integration issues

International Nuclear Information System (INIS)

Determan, W.R.; Harty, R.B.

1988-01-01

The Department of Energy, in cooperation with the Department of Defense, has recently initiated the dynamic isotope power system (DIPS) demonstration program. DIPS is designed to provide 1 to 10 kW of electrical power for future military spacecraft. One of the near-term missions considered as a potential application for DIPS was the boost surveillance and tracking system (BSTS). A brief review and summary of the reasons behind a selection of DIPS for BSTS-type missions is presented. Many of these are directly related to spacecraft integration issues; these issues will be reviewed in the areas of system safety, operations, survivability, reliability, and autonomy

SEQ-POINTER: Next generation, planetary spacecraft remote sensing science observation design tool

Science.gov (United States)

Boyer, Jeffrey S.

1994-11-01

Since Mariner, NASA-JPL planetary missions have been supported by ground software to plan and design remote sensing science observations. The software used by the science and sequence designers to plan and design observations has evolved with mission and technological advances. The original program, PEGASIS (Mariners 4, 6, and 7), was re-engineered as POGASIS (Mariner 9, Viking, and Mariner 10), and again later as POINTER (Voyager and Galileo). Each of these programs were developed under technological, political, and fiscal constraints which limited their adaptability to other missions and spacecraft designs. Implementation of a multi-mission tool, SEQ POINTER, under the auspices of the JPL Multimission Operations Systems Office (MOSO) is in progress. This version has been designed to address the limitations experienced on previous versions as they were being adapted to a new mission and spacecraft. The tool has been modularly designed with subroutine interface structures to support interchangeable celestial body and spacecraft definition models. The computational and graphics modules have also been designed to interface with data collected from previous spacecraft, or on-going observations, which describe the surface of each target body. These enhancements make SEQ POINTER a candidate for low-cost mission usage, when a remote sensing science observation design capability is required. The current and planned capabilities of the tool will be discussed. The presentation will also include a 5-10 minute video presentation demonstrating the capabilities of a proto-Cassini Project version that was adapted to test the tool. The work described in this abstract was performed by the Jet Propulsion Laboratory, California Institute of Technology, under contract to the National Aeronautics and Space Administration.

REQUIREMENTS FOR IMAGE QUALITY OF EMERGENCY SPACECRAFTS

Directory of Open Access Journals (Sweden)

A. I. Altukhov

2015-05-01

Full Text Available The paper deals with the method for formation of quality requirements to the images of emergency spacecrafts. The images are obtained by means of remote sensing of near-earth space orbital deployment in the visible range. of electromagnetic radiation. The method is based on a joint taking into account conditions of space survey, characteristics of surveillance equipment, main design features of the observed spacecrafts and orbital inspection tasks. Method. Quality score is the predicted linear resolution image that gives the possibility to create a complete view of pictorial properties of the space image obtained by electro-optical system from the observing satellite. Formulation of requirements to the numerical value of this indicator is proposed to perform based on the properties of remote sensing system, forming images in the conditions of outer space, and the properties of the observed emergency spacecraft: dimensions, platform construction of the satellite, on-board equipment placement. For method implementation the authors have developed a predictive model of requirements to a linear resolution for images of emergency spacecrafts, making it possible to select the intervals of space shooting and get the satellite images required for quality interpretation. Main results. To verify the proposed model functionality we have carried out calculations of the numerical values for the linear resolution of the image, ensuring the successful task of determining the gross structural damage of the spacecrafts and identifying changes in their spatial orientation. As input data were used with dimensions and geometric primitives corresponding to the shape of deemed inspected spacecrafts: Resurs-P", "Canopus-B", "Electro-L". Numerical values of the linear resolution images have been obtained, ensuring the successful task solution for determining the gross structural damage of spacecrafts.

Electronics for embedded systems

CERN Document Server

Bindal, Ahmet

2017-01-01

This book provides semester-length coverage of electronics for embedded systems, covering most common analog and digital circuit-related issues encountered while designing embedded system hardware. It is written for students and young professionals who have basic circuit theory background and want to learn more about passive circuits, diode and bipolar transistor circuits, the state-of-the-art CMOS logic family and its interface with older logic families such as TTL, sensors and sensor physics, operational amplifier circuits to condition sensor signals, data converters and various circuits used in electro-mechanical device control in embedded systems. The book also provides numerous hardware design examples by integrating the topics learned in earlier chapters. The last chapter extensively reviews the combinational and sequential logic design principles to be able to design the digital part of embedded system hardware.

Deep embedding convolutional neural network for synthesizing CT image from T1-Weighted MR image.

Science.gov (United States)

Xiang, Lei; Wang, Qian; Nie, Dong; Zhang, Lichi; Jin, Xiyao; Qiao, Yu; Shen, Dinggang

2018-07-01

Recently, more and more attention is drawn to the field of medical image synthesis across modalities. Among them, the synthesis of computed tomography (CT) image from T1-weighted magnetic resonance (MR) image is of great importance, although the mapping between them is highly complex due to large gaps of appearances of the two modalities. In this work, we aim to tackle this MR-to-CT synthesis task by a novel deep embedding convolutional neural network (DECNN). Specifically, we generate the feature maps from MR images, and then transform these feature maps forward through convolutional layers in the network. We can further compute a tentative CT synthesis from the midway of the flow of feature maps, and then embed this tentative CT synthesis result back to the feature maps. This embedding operation results in better feature maps, which are further transformed forward in DECNN. After repeating this embedding procedure for several times in the network, we can eventually synthesize a final CT image in the end of the DECNN. We have validated our proposed method on both brain and prostate imaging datasets, by also comparing with the state-of-the-art methods. Experimental results suggest that our DECNN (with repeated embedding operations) demonstrates its superior performances, in terms of both the perceptive quality of the synthesized CT image and the run-time cost for synthesizing a CT image. Copyright © 2018. Published by Elsevier B.V.

Nuclear-powered Hysat spacecraft: comparative design study

International Nuclear Information System (INIS)

Raab, B.

1975-08-01

The study shows that the all-nuclear spacecraft can have a substantial weight advantage over a hybrid (nuclear/solar) or all-solar spacecraft, owing to a further reduction in power requirement, and to the elimination of such equipment as the sensor gimbal and rotating joint assemblies. Because the need for a sun-oriented section is eliminated, the all-nuclear spacecraft can be designed as a monolithic structure, with the sensor and other payload firmly secured in a fixed position on the structure. This enhances attitude stability while minimizing structural weight and eliminating the need for flexible fluid lines. Sensor motion can be produced, varied, and controlled within the limits specified by the study contractors by moving the entire spacecraft in the prescribed pattern. A simple attitude control system using available hardware suffices to meet all requirements

Noncommutative spaces and matrix embeddings on flat ℝ{sup 2n+1}

Energy Technology Data Exchange (ETDEWEB)

Karczmarek, Joanna L.; Yeh, Ken Huai-Che [Department of Physics and Astronomy, University of British Columbia,6224 Agricultural Road, Vancouver (Canada)

2015-11-23

We conjecture an embedding operator which assigns, to any 2n+1 hermitian matrices, a 2n-dimensional hypersurface in flat (2n+1)-dimensional Euclidean space. This corresponds to precisely defining a fuzzy D(2n)-brane corresponding to N D0-branes. Points on the emergent hypersurface correspond to zero eigenstates of the embedding operator, which have an interpretation as coherent states underlying the emergent noncommutative geometry. Using this correspondence, all physical properties of the emergent D(2n)-brane can be computed. We apply our conjecture to noncommutative flat and spherical spaces. As a by-product, we obtain a construction of a rotationally symmetric flat noncommutative space in 4 dimensions.

Learning Word Embeddings with Chi-Square Weights for Healthcare Tweet Classification

Directory of Open Access Journals (Sweden)

Sicong Kuang

2017-08-01

Full Text Available Twitter is a popular source for the monitoring of healthcare information and public disease. However, there exists much noise in the tweets. Even though appropriate keywords appear in the tweets, they do not guarantee the identification of a truly health-related tweet. Thus, the traditional keyword-based classification task is largely ineffective. Algorithms for word embeddings have proved to be useful in many natural language processing (NLP tasks. We introduce two algorithms based on an existing word embedding learning algorithm: the continuous bag-of-words model (CBOW. We apply the proposed algorithms to the task of recognizing healthcare-related tweets. In the CBOW model, the vector representation of words is learned from their contexts. To simplify the computation, the context is represented by an average of all words inside the context window. However, not all words in the context window contribute equally to the prediction of the target word. Greedily incorporating all the words in the context window will largely limit the contribution of the useful semantic words and bring noisy or irrelevant words into the learning process, while existing word embedding algorithms also try to learn a weighted CBOW model. Their weights are based on existing pre-defined syntactic rules while ignoring the task of the learned embedding. We propose learning weights based on the words’ relative importance in the classification task. Our intuition is that such learned weights place more emphasis on words that have comparatively more to contribute to the later task. We evaluate the embeddings learned from our algorithms on two healthcare-related datasets. The experimental results demonstrate that embeddings learned from the proposed algorithms outperform existing techniques by a relative accuracy improvement of over 9%.

Brauer type embedding problems

CERN Document Server

Ledet, Arne

2005-01-01

This monograph is concerned with Galois theoretical embedding problems of so-called Brauer type with a focus on 2-groups and on finding explicit criteria for solvability and explicit constructions of the solutions. The advantage of considering Brauer type embedding problems is their comparatively simple condition for solvability in the form of an obstruction in the Brauer group of the ground field. This book presupposes knowledge of classical Galois theory and the attendant algebra. Before considering questions of reducing the embedding problems and reformulating the solvability criteria, the

Simulation of embedded systems for energy consumption estimation

Energy Technology Data Exchange (ETDEWEB)

Lafond, S.

2009-07-01

Technology developments in semiconductor fabrication along with a rapid expansion of the market for portable devices, such as PDAs and mobile phones, make the energy consumption of embedded systems a major problem. Indeed the need to provide an increasing number of computational intensive applications and at the same time to maximize the battery life of portable devices can be seen as incompatible trends. System simulation is a flexible and convenient method for analyzinging and exploring the performance of a system or sub-system. At the same time, the increasing use of computational intensive applications strengthens the need to maximize the battery life of portable devices. As a consequence, the simulation of embedded systems for energy consumption estimation is becoming essential in order to study and explore the influence of system design choices on the system energy consumption. The original publications presented in the second part of this thesis propose several frameworks for evaluating the effects of particular system and software architectures on the system energy consumption. From a software point of view Java and C based applications are studied, and from a hardware perspective systems using general purpose processor and heterogeneous platforms with dedicated hardware accelerators are analyzed. Papers 1 and 2 present a framework for estimating the energy consumption of an embedded Java Virtual Machine and show how an accurate energy consumption model of Java opcodes can be obtained. Paper 3 evaluates the cost-effectiveness of Forward Error Correction algorithms in terms of energy consumption and demonstrates that a substantial energy saving is achievable in a DVB-H receiver when a FEC algorithm is used for file downloading scenarios. Paper 4 and 5 present the simulation of heterogeneous platforms and point out the drawback of different mechanisms used to synchronize a hardware accelerator used as a peripheral device. Paper 6 shows that the use of a multi

Permutation entropy with vector embedding delays

Science.gov (United States)

Little, Douglas J.; Kane, Deb M.

2017-12-01

Permutation entropy (PE) is a statistic used widely for the detection of structure within a time series. Embedding delay times at which the PE is reduced are characteristic timescales for which such structure exists. Here, a generalized scheme is investigated where embedding delays are represented by vectors rather than scalars, permitting PE to be calculated over a (D -1 ) -dimensional space, where D is the embedding dimension. This scheme is applied to numerically generated noise, sine wave and logistic map series, and experimental data sets taken from a vertical-cavity surface emitting laser exhibiting temporally localized pulse structures within the round-trip time of the laser cavity. Results are visualized as PE maps as a function of embedding delay, with low PE values indicating combinations of embedding delays where correlation structure is present. It is demonstrated that vector embedding delays enable identification of structure that is ambiguous or masked, when the embedding delay is constrained to scalar form.

Computer graphics aid mission operations. [NASA missions

Science.gov (United States)

Jeletic, James F.

1990-01-01

The application of computer graphics techniques in NASA space missions is reviewed. Telemetric monitoring of the Space Shuttle and its components is discussed, noting the use of computer graphics for real-time visualization problems in the retrieval and repair of the Solar Maximum Mission. The use of the world map display for determining a spacecraft's location above the earth and the problem of verifying the relative position and orientation of spacecraft to celestial bodies are examined. The Flight Dynamics/STS Three-dimensional Monitoring System and the Trajectroy Computations and Orbital Products System world map display are described, emphasizing Space Shuttle applications. Also, consideration is given to the development of monitoring systems such as the Shuttle Payloads Mission Monitoring System and the Attitude Heads-Up Display and the use of the NASA-Goddard Two-dimensional Graphics Monitoring System during Shuttle missions and to support the Hubble Space Telescope.

Advanced Solar-propelled Cargo Spacecraft for Mars Missions

Science.gov (United States)

Auziasdeturenne, Jacqueline; Beall, Mark; Burianek, Joseph; Cinniger, Anna; Dunmire, Barbrina; Haberman, Eric; Iwamoto, James; Johnson, Stephen; Mccracken, Shawn; Miller, Melanie

1989-01-01

Three concepts for an unmanned, solar powered, cargo spacecraft for Mars support missions were investigated. These spacecraft are designed to carry a 50,000 kg payload from a low Earth orbit to a low Mars orbit. Each design uses a distinctly different propulsion system: A Solar Radiation Absorption (SRA) system, a Solar-Pumped Laser (SPL) system and a solar powered magnetoplasmadynamic (MPD) arc system. The SRA directly converts solar energy to thermal energy in the propellant through a novel process. In the SPL system, a pair of solar-pumped, multi-megawatt, CO2 lasers in sunsynchronous Earth orbit converts solar energy to laser energy. The MPD system used indium phosphide solar cells to convert sunlight to electricity, which powers the propulsion system. Various orbital transfer options are examined for these concepts. In the SRA system, the mother ship transfers the payload into a very high Earth orbit and a small auxiliary propulsion system boosts the payload into a Hohmann transfer to Mars. The SPL spacecraft and the SPL powered spacecraft return to Earth for subsequent missions. The MPD propelled spacecraft, however, remains at Mars as an orbiting space station. A patched conic approximation was used to determine a heliocentric interplanetary transfer orbit for the MPD propelled spacecraft. All three solar-powered spacecraft use an aerobrake procedure to place the payload into a low Mars parking orbit. The payload delivery times range from 160 days to 873 days (2.39 years).

Common data buffer system. [communication with computational equipment utilized in spacecraft operations

Science.gov (United States)

Byrne, F. (Inventor)

1981-01-01

A high speed common data buffer system is described for providing an interface and communications medium between a plurality of computers utilized in a distributed computer complex forming part of a checkout, command and control system for space vehicles and associated ground support equipment. The system includes the capability for temporarily storing data to be transferred between computers, for transferring a plurality of interrupts between computers, for monitoring and recording these transfers, and for correcting errors incurred in these transfers. Validity checks are made on each transfer and appropriate error notification is given to the computer associated with that transfer.

Connes' embedding problem and winning strategies for quantum XOR games

Science.gov (United States)

Harris, Samuel J.

2017-12-01

We consider quantum XOR games, defined in the work of Regev and Vidick [ACM Trans. Comput. Theory 7, 43 (2015)], from the perspective of unitary correlations defined in the work of Harris and Paulsen [Integr. Equations Oper. Theory 89, 125 (2017)]. We show that the winning bias of a quantum XOR game in the tensor product model (respectively, the commuting model) is equal to the norm of its associated linear functional on the unitary correlation set from the appropriate model. We show that Connes' embedding problem has a positive answer if and only if every quantum XOR game has entanglement bias equal to the commuting bias. In particular, the embedding problem is equivalent to determining whether every quantum XOR game G with a winning strategy in the commuting model also has a winning strategy in the approximate finite-dimensional model.

Integration of distributed computing into the drug discovery process.

Science.gov (United States)

von Korff, Modest; Rufener, Christian; Stritt, Manuel; Freyss, Joel; Bär, Roman; Sander, Thomas

2011-02-01

Grid computing offers an opportunity to gain massive computing power at low costs. We give a short introduction into the drug discovery process and exemplify the use of grid computing for image processing, docking and 3D pharmacophore descriptor calculations. The principle of a grid and its architecture are briefly explained. More emphasis is laid on the issues related to a company-wide grid installation and embedding the grid into the research process. The future of grid computing in drug discovery is discussed in the expert opinion section. Most needed, besides reliable algorithms to predict compound properties, is embedding the grid seamlessly into the discovery process. User friendly access to powerful algorithms without any restrictions, that is, by a limited number of licenses, has to be the goal of grid computing in drug discovery.

Spacecraft Multiple Array Communication System Performance Analysis

Science.gov (United States)

Hwu, Shian U.; Desilva, Kanishka; Sham, Catherine C.

2010-01-01

The Communication Systems Simulation Laboratory (CSSL) at the NASA Johnson Space Center is tasked to perform spacecraft and ground network communication system simulations, design validation, and performance verification. The CSSL has developed simulation tools that model spacecraft communication systems and the space and ground environment in which the tools operate. In this paper, a spacecraft communication system with multiple arrays is simulated. Multiple array combined technique is used to increase the radio frequency coverage and data rate performance. The technique is to achieve phase coherence among the phased arrays to combine the signals at the targeting receiver constructively. There are many technical challenges in spacecraft integration with a high transmit power communication system. The array combining technique can improve the communication system data rate and coverage performances without increasing the system transmit power requirements. Example simulation results indicate significant performance improvement can be achieved with phase coherence implementation.

Spacecraft Spin Test Facility

Data.gov (United States)

Federal Laboratory Consortium — FUNCTION: Provides the capability to correct unbalances of spacecraft by using dynamic measurement techniques and static/coupled measurements to provide products of...

Integrated Optical Interconnect Architectures for Embedded Systems

CERN Document Server

Nicolescu, Gabriela

2013-01-01

This book provides a broad overview of current research in optical interconnect technologies and architectures. Introductory chapters on high-performance computing and the associated issues in conventional interconnect architectures, and on the fundamental building blocks for integrated optical interconnect, provide the foundations for the bulk of the book which brings together leading experts in the field of optical interconnect architectures for data communication. Particular emphasis is given to the ways in which the photonic components are assembled into architectures to address the needs of data-intensive on-chip communication, and to the performance evaluation of such architectures for specific applications.   Provides state-of-the-art research on the use of optical interconnects in Embedded Systems; Begins with coverage of the basics for high-performance computing and optical interconnect; Includes a variety of on-chip optical communication topologies; Features coverage of system integration and opti...

Spacecraft Swarm Coordination and Planning Tool, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Fractionated spacecraft architectures to distribute mission performance from a single, monolithic satellite across large number of smaller spacecraft, for missions...

Practical Applications of Cosmic Ray Science: Spacecraft, Aircraft, Ground-Based Computation and Control Systems, and Human Health and Safety

Science.gov (United States)

Atwell, William; Koontz, Steve; Normand, Eugene

2012-01-01

Three twentieth century technological developments, 1) high altitude commercial and military aircraft; 2) manned and unmanned spacecraft; and 3) increasingly complex and sensitive solid state micro-electronics systems, have driven an ongoing evolution of basic cosmic ray science into a set of practical engineering tools needed to design, test, and verify the safety and reliability of modern complex technological systems. The effects of primary cosmic ray particles and secondary particle showers produced by nuclear reactions with the atmosphere, can determine the design and verification processes (as well as the total dollar cost) for manned and unmanned spacecraft avionics systems. Similar considerations apply to commercial and military aircraft operating at high latitudes and altitudes near the atmospheric Pfotzer maximum. Even ground based computational and controls systems can be negatively affected by secondary particle showers at the Earth s surface, especially if the net target area of the sensitive electronic system components is large. Finally, accumulation of both primary cosmic ray and secondary cosmic ray induced particle shower radiation dose is an important health and safety consideration for commercial or military air crews operating at high altitude/latitude and is also one of the most important factors presently limiting manned space flight operations beyond low-Earth orbit (LEO). In this paper we review the discovery of cosmic ray effects on the performance and reliability of microelectronic systems as well as human health and the development of the engineering and health science tools used to evaluate and mitigate cosmic ray effects in ground-based atmospheric flight, and space flight environments. Ground test methods applied to microelectronic components and systems are used in combinations with radiation transport and reaction codes to predict the performance of microelectronic systems in their operating environments. Similar radiation transport

Introduction Of Computational Materials Science

International Nuclear Information System (INIS)

Lee, Jun Geun

2006-08-01

This book gives, descriptions of computer simulation, computational materials science, typical three ways of computational materials science, empirical methods ; molecular dynamics such as potential energy, Newton's equation of motion, data production and analysis of results, quantum mechanical methods like wave equation, approximation, Hartree method, and density functional theory, dealing of solid such as pseudopotential method, tight-binding methods embedded atom method, Car-Parrinello method and combination simulation.

A report on SHARP (Spacecraft Health Automated Reasoning Prototype) and the Voyager Neptune encounter

Science.gov (United States)

Martin, R. G. (Editor); Atkinson, D. J.; James, M. L.; Lawson, D. L.; Porta, H. J.

1990-01-01

The development and application of the Spacecraft Health Automated Reasoning Prototype (SHARP) for the operations of the telecommunications systems and link analysis functions in Voyager mission operations are presented. An overview is provided of the design and functional description of the SHARP system as it was applied to Voyager. Some of the current problems and motivations for automation in real-time mission operations are discussed, as are the specific solutions that SHARP provides. The application of SHARP to Voyager telecommunications had the goal of being a proof-of-capability demonstration of artificial intelligence as applied to the problem of real-time monitoring functions in planetary mission operations. AS part of achieving this central goal, the SHARP application effort was also required to address the issue of the design of an appropriate software system architecture for a ground-based, highly automated spacecraft monitoring system for mission operations, including methods for: (1) embedding a knowledge-based expert system for fault detection, isolation, and recovery within this architecture; (2) acquiring, managing, and fusing the multiple sources of information used by operations personnel; and (3) providing information-rich displays to human operators who need to exercise the capabilities of the automated system. In this regard, SHARP has provided an excellent example of how advanced artificial intelligence techniques can be smoothly integrated with a variety of conventionally programmed software modules, as well as guidance and solutions for many questions about automation in mission operations.

Attitude Estimation in Fractionated Spacecraft Cluster Systems

Science.gov (United States)

Hadaegh, Fred Y.; Blackmore, James C.

2011-01-01

An attitude estimation was examined in fractioned free-flying spacecraft. Instead of a single, monolithic spacecraft, a fractionated free-flying spacecraft uses multiple spacecraft modules. These modules are connected only through wireless communication links and, potentially, wireless power links. The key advantage of this concept is the ability to respond to uncertainty. For example, if a single spacecraft module in the cluster fails, a new one can be launched at a lower cost and risk than would be incurred with onorbit servicing or replacement of the monolithic spacecraft. In order to create such a system, however, it is essential to know what the navigation capabilities of the fractionated system are as a function of the capabilities of the individual modules, and to have an algorithm that can perform estimation of the attitudes and relative positions of the modules with fractionated sensing capabilities. Looking specifically at fractionated attitude estimation with startrackers and optical relative attitude sensors, a set of mathematical tools has been developed that specify the set of sensors necessary to ensure that the attitude of the entire cluster ( cluster attitude ) can be observed. Also developed was a navigation filter that can estimate the cluster attitude if these conditions are satisfied. Each module in the cluster may have either a startracker, a relative attitude sensor, or both. An extended Kalman filter can be used to estimate the attitude of all modules. A range of estimation performances can be achieved depending on the sensors used and the topology of the sensing network.

Smart Multicore Embedded Systems

DEFF Research Database (Denmark)

This book provides a single-source reference to the state-of-the-art of high-level programming models and compilation tool-chains for embedded system platforms. The authors address challenges faced by programmers developing software to implement parallel applications in embedded systems, where ve...

Systems analysis and the computer

Energy Technology Data Exchange (ETDEWEB)

Douglas, A S

1983-08-01

The words systems analysis are used in at least two senses. Whilst the general nature of the topic is well understood in the or community, the nature of the term as used by computer scientists is less familiar. In this paper, the nature of systems analysis as it relates to computer-based systems is examined from the point of view that the computer system is an automaton embedded in a human system, and some facets of this are explored. It is concluded that or analysts and computer analysts have things to learn from each other and that this ought to be reflected in their education. The important role played by change in the design of systems is also highlighted, and it is concluded that, whilst the application of techniques developed in the artificial intelligence field have considerable relevance to constructing automata able to adapt to change in the environment, study of the human factors affecting the overall systems within which the automata are embedded has an even more important role. 19 references.

Experimental study of reinforced concrete pile caps with external, embedded and partially embedded socket with smooth interface

Directory of Open Access Journals (Sweden)

R. Barros

Full Text Available On Precast concrete structures the column foundation connections can occur through the socket foundation, which can be embedded, partially embedded or external, with socket walls over the pile caps. This paper presents an experimental study about two pile caps reinforced concrete with external, partially embedded and embedded socket submitted to central load, using 1:2 scaled models. In the analyzed models, the smooth interface between the socket walls and column was considered. The results are compared to a reference model that presents monolithic connections between the column and pile cap. It is observed that the ultimate load of pile cap with external sockets has the same magnitude as the reference pile cap, but the ultimate load of models with partially embedded and embedded socket present less magnitude than the reference model.

Methods library of embedded R functions at Statistics Norway

Directory of Open Access Journals (Sweden)

Øyvind Langsrud

2017-11-01

Full Text Available Statistics Norway is modernising the production processes. An important element in this work is a library of functions for statistical computations. In principle, the functions in such a methods library can be programmed in several languages. A modernised production environment demand that these functions can be reused for different statistics products, and that they are embedded within a common IT system. The embedding should be done in such a way that the users of the methods do not need to know the underlying programming language. As a proof of concept, Statistics Norway soon has established a methods library offering a limited number of methods for macro-editing, imputation and confidentiality. This is done within an area of municipal statistics with R as the only programming language. This paper presents the details and experiences from this work. The problem of fitting real word applications to simple and strict standards is discussed and exemplified by the development of solutions to regression imputation and table suppression.

Airborne particulate matter in spacecraft

Science.gov (United States)

1988-01-01

Acceptability limits and sampling and monitoring strategies for airborne particles in spacecraft were considered. Based on instances of eye and respiratory tract irritation reported by Shuttle flight crews, the following acceptability limits for airborne particles were recommended: for flights of 1 week or less duration (1 mg/cu m for particles less than 10 microns in aerodynamic diameter (AD) plus 1 mg/cu m for particles 10 to 100 microns in AD); and for flights greater than 1 week and up to 6 months in duration (0.2 mg/cu m for particles less than 10 microns in AD plus 0.2 mg/cu m for particles 10 to 100 microns in AD. These numerical limits were recommended to aid in spacecraft atmosphere design which should aim at particulate levels that are a low as reasonably achievable. Sampling of spacecraft atmospheres for particles should include size-fractionated samples of 0 to 10, 10 to 100, and greater than 100 micron particles for mass concentration measurement and elementary chemical analysis by nondestructive analysis techniques. Morphological and chemical analyses of single particles should also be made to aid in identifying airborne particulate sources. Air cleaning systems based on inertial collection principles and fine particle collection devices based on electrostatic precipitation and filtration should be considered for incorporation into spacecraft air circulation systems. It was also recommended that research be carried out in space in the areas of health effects and particle characterization.

Fifty-one years of Los Alamos Spacecraft

Energy Technology Data Exchange (ETDEWEB)

Fenimore, Edward E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2014-09-04

From 1963 to 2014, the Los Alamos National Laboratory was involved in at least 233 spacecraft. There are probably only one or two institutions in the world that have been involved in so many spacecraft. Los Alamos space exploration started with the Vela satellites for nuclear test detection, but soon expanded to ionospheric research (mostly barium releases), radioisotope thermoelectric generators, solar physics, solar wind, magnetospheres, astrophysics, national security, planetary physics, earth resources, radio propagation in the ionosphere, and cubesats. Here, we present a list of the spacecraft, their purpose, and their launch dates for use during RocketFest

Remodeling Air Force Cyber Command and Control

Science.gov (United States)

2017-10-10

Internet, telecommunications networks, computer systems , and embedded processors and controllers .” That last phrase includes processors and controllers ...embedded” into weapons systems , including aircraft and spacecraft. Many weapon systems were built and connected before cyberspace became a...problems for systemic improvement of mission assurance. The benefit of a centralized environment could also extend to improving enterprise-level patch

Hard real-time multibody simulations using ARM-based embedded systems

Energy Technology Data Exchange (ETDEWEB)

Pastorino, Roland, E-mail: roland.pastorino@kuleuven.be, E-mail: rpastorino@udc.es; Cosco, Francesco, E-mail: francesco.cosco@kuleuven.be; Naets, Frank, E-mail: frank.naets@kuleuven.be; Desmet, Wim, E-mail: wim.desmet@kuleuven.be [KU Leuven, PMA division, Department of Mechanical Engineering (Belgium); Cuadrado, Javier, E-mail: javicuad@cdf.udc.es [Universidad de La Coruña, Laboratorio de Ingeniería Mecánica (Spain)

2016-05-15

The real-time simulation of multibody models on embedded systems is of particular interest for controllers and observers such as model predictive controllers and state observers, which rely on a dynamic model of the process and are customarily executed in electronic control units. This work first identifies the software techniques and tools required to easily write efficient code for multibody models to be simulated on ARM-based embedded systems. Automatic Programming and Source Code Translation are the two techniques that were chosen to generate source code for multibody models in different programming languages. Automatic Programming is used to generate procedural code in an intermediate representation from an object-oriented library and Source Code Translation is used to translate the intermediate representation automatically to an interpreted language or to a compiled language for efficiency purposes. An implementation of these techniques is proposed. It is based on a Python template engine and AST tree walkers for Source Code Generation and on a model-driven translator for the Source Code Translation. The code is translated from a metalanguage to any of the following four programming languages: Python-Numpy, Matlab, C++-Armadillo, C++-Eigen. Two examples of multibody models were simulated: a four-bar linkage with multiple loops and a 3D vehicle steering system. The code for these examples has been generated and executed on two ARM-based single-board computers. Using compiled languages, both models could be simulated faster than real-time despite the low resources and performance of these embedded systems. Finally, the real-time performance of both models was evaluated when executed in hard real-time on Xenomai for both embedded systems. This work shows through measurements that Automatic Programming and Source Code Translation are valuable techniques to develop real-time multibody models to be used in embedded observers and controllers.

Hard real-time multibody simulations using ARM-based embedded systems

International Nuclear Information System (INIS)

Pastorino, Roland; Cosco, Francesco; Naets, Frank; Desmet, Wim; Cuadrado, Javier

2016-01-01

The real-time simulation of multibody models on embedded systems is of particular interest for controllers and observers such as model predictive controllers and state observers, which rely on a dynamic model of the process and are customarily executed in electronic control units. This work first identifies the software techniques and tools required to easily write efficient code for multibody models to be simulated on ARM-based embedded systems. Automatic Programming and Source Code Translation are the two techniques that were chosen to generate source code for multibody models in different programming languages. Automatic Programming is used to generate procedural code in an intermediate representation from an object-oriented library and Source Code Translation is used to translate the intermediate representation automatically to an interpreted language or to a compiled language for efficiency purposes. An implementation of these techniques is proposed. It is based on a Python template engine and AST tree walkers for Source Code Generation and on a model-driven translator for the Source Code Translation. The code is translated from a metalanguage to any of the following four programming languages: Python-Numpy, Matlab, C++-Armadillo, C++-Eigen. Two examples of multibody models were simulated: a four-bar linkage with multiple loops and a 3D vehicle steering system. The code for these examples has been generated and executed on two ARM-based single-board computers. Using compiled languages, both models could be simulated faster than real-time despite the low resources and performance of these embedded systems. Finally, the real-time performance of both models was evaluated when executed in hard real-time on Xenomai for both embedded systems. This work shows through measurements that Automatic Programming and Source Code Translation are valuable techniques to develop real-time multibody models to be used in embedded observers and controllers.

EOS: A project to investigate the design and construction of real-time distributed Embedded Operating Systems

Science.gov (United States)

Campbell, R. H.; Essick, Ray B.; Johnston, Gary; Kenny, Kevin; Russo, Vince

1987-01-01

Project EOS is studying the problems of building adaptable real-time embedded operating systems for the scientific missions of NASA. Choices (A Class Hierarchical Open Interface for Custom Embedded Systems) is an operating system designed and built by Project EOS to address the following specific issues: the software architecture for adaptable embedded parallel operating systems, the achievement of high-performance and real-time operation, the simplification of interprocess communications, the isolation of operating system mechanisms from one another, and the separation of mechanisms from policy decisions. Choices is written in C++ and runs on a ten processor Encore Multimax. The system is intended for use in constructing specialized computer applications and research on advanced operating system features including fault tolerance and parallelism.

An Embedded Sensor Node Microcontroller with Crypto-Processors.

Science.gov (United States)

Panić, Goran; Stecklina, Oliver; Stamenković, Zoran

2016-04-27

Wireless sensor network applications range from industrial automation and control, agricultural and environmental protection, to surveillance and medicine. In most applications, data are highly sensitive and must be protected from any type of attack and abuse. Security challenges in wireless sensor networks are mainly defined by the power and computing resources of sensor devices, memory size, quality of radio channels and susceptibility to physical capture. In this article, an embedded sensor node microcontroller designed to support sensor network applications with severe security demands is presented. It features a low power 16-bitprocessor core supported by a number of hardware accelerators designed to perform complex operations required by advanced crypto algorithms. The microcontroller integrates an embedded Flash and an 8-channel 12-bit analog-to-digital converter making it a good solution for low-power sensor nodes. The article discusses the most important security topics in wireless sensor networks and presents the architecture of the proposed hardware solution. Furthermore, it gives details on the chip implementation, verification and hardware evaluation. Finally, the chip power dissipation and performance figures are estimated and analyzed.

Developing a multimodal biometric authentication system using soft computing methods.

Science.gov (United States)

Malcangi, Mario

2015-01-01

Robust personal authentication is becoming ever more important in computer-based applications. Among a variety of methods, biometric offers several advantages, mainly in embedded system applications. Hard and soft multi-biometric, combined with hard and soft computing methods, can be applied to improve the personal authentication process and to generalize the applicability. This chapter describes the embedded implementation of a multi-biometric (voiceprint and fingerprint) multimodal identification system based on hard computing methods (DSP) for feature extraction and matching, an artificial neural network (ANN) for soft feature pattern matching, and a fuzzy logic engine (FLE) for data fusion and decision.

Training for spacecraft technical analysts

Science.gov (United States)

Ayres, Thomas J.; Bryant, Larry

1989-01-01

Deep space missions such as Voyager rely upon a large team of expert analysts who monitor activity in the various engineering subsystems of the spacecraft and plan operations. Senior teammembers generally come from the spacecraft designers, and new analysts receive on-the-job training. Neither of these methods will suffice for the creation of a new team in the middle of a mission, which may be the situation during the Magellan mission. New approaches are recommended, including electronic documentation, explicit cognitive modeling, and coached practice with archived data.

Efficient and Secure Fingerprint Verification for Embedded Devices

Directory of Open Access Journals (Sweden)

Sakiyama Kazuo

2006-01-01

Full Text Available This paper describes a secure and memory-efficient embedded fingerprint verification system. It shows how a fingerprint verification module originally developed to run on a workstation can be transformed and optimized in a systematic way to run real-time on an embedded device with limited memory and computation power. A complete fingerprint recognition module is a complex application that requires in the order of 1000 M unoptimized floating-point instruction cycles. The goal is to run both the minutiae extraction and the matching engines on a small embedded processor, in our case a 50 MHz LEON-2 softcore. It does require optimization and acceleration techniques at each design step. In order to speed up the fingerprint signal processing phase, we propose acceleration techniques at the algorithm level, at the software level to reduce the execution cycle number, and at the hardware level to distribute the system work load. Thirdly, a memory trace map-based memory reduction strategy is used for lowering the system memory requirement. Lastly, at the hardware level, it requires the development of specialized coprocessors. As results of these optimizations, we achieve a 65% reduction on the execution time and a 67% reduction on the memory storage requirement for the minutiae extraction process, compared against the reference implementation. The complete operation, that is, fingerprint capture, feature extraction, and matching, can be done in real-time of less than 4 seconds

Reconfigurable Computing

CERN Document Server

Cardoso, Joao MP

2011-01-01

As the complexity of modern embedded systems increases, it becomes less practical to design monolithic processing platforms. As a result, reconfigurable computing is being adopted widely for more flexible design. Reconfigurable Computers offer the spatial parallelism and fine-grained customizability of application-specific circuits with the postfabrication programmability of software. To make the most of this unique combination of performance and flexibility, designers need to be aware of both hardware and software issues. FPGA users must think not only about the gates needed to perform a comp

Poincare ball embeddings of the optical geometry

International Nuclear Information System (INIS)

Abramowicz, M A; Bengtsson, I; Karas, V; Rosquist, K

2002-01-01

It is shown that the optical geometry of the Reissner-Nordstroem exterior metric can be embedded in a hyperbolic space all the way down to its outer horizon. The adopted embedding procedure removes a breakdown of flat-space embeddings which occurs outside the horizon, at and below the Buchdahl-Bondi limit (R/M=9/4 in the Schwarzschild case). In particular, the horizon can be captured in the optical geometry embedding diagram. Moreover, by using the compact Poincare ball representation of the hyperbolic space, the embedding diagram can cover the whole extent of radius from spatial infinity down to the horizon. Attention is drawn to the advantages of such embeddings in an appropriately curved space: this approach gives compact embeddings and it clearly distinguishes the case of an extremal black hole from a non-extremal one in terms of the topology of the embedded horizon

Low power arcjet system spacecraft impacts

Science.gov (United States)

Pencil, Eric J.; Sarmiento, Charles J.; Lichtin, D. A.; Palchefsky, J. W.; Bogorad, A. L.

1993-01-01

Potential plume contamination of spacecraft surfaces was investigated by positioning spacecraft material samples relative to an arcjet thruster. Samples in the simulated solar array region were exposed to the cold gas arcjet plume for 40 hrs to address concerns about contamination by backstreaming diffusion pump oil. Except for one sample, no significant changes were measured in absorptance and emittance within experimental error. Concerns about surface property degradation due to electrostatic discharges led to the investigation of the discharge phenomenon of charged samples during arcjet ignition. Short duration exposure of charged samples demonstrated that potential differences are consistently and completely eliminated within the first second of exposure to a weakly ionized plume. The spark discharge mechanism was not the discharge phenomenon. The results suggest that the arcjet could act as a charge control device on spacecraft.

Homomorphic embeddings in n-groups

Directory of Open Access Journals (Sweden)

Mona Cristescu

2013-06-01

Full Text Available We prove that an cancellative n-groupoid A can be homotopic embedded in an n-group if and only if in A are satisfied all n-ary Malcev conditions. Now we shall prove that in the presence of associative law we obtain homomorphic embeddings. Furthermore, if A has a lateral identity a such embeddings is assured by a subset of n-ary Malcev conditions - unary Malcev conditions.

Multi-spacecraft observations of solar hard X-ray bursts

International Nuclear Information System (INIS)

Kane, S.R.

1981-01-01

The role of multi-spacecraft observations in solar flare research is examined from the point of view of solar hard X-ray bursts and their implications with respect to models of the impulsive phase. Multi-spacecraft measurements provide a stereoscopic view of the flare region, and hence represent the only direct method of measuring directivity of X-rays. In absence of hard X-ray imaging instruments with high spatial and temporal resolution, multi-spacecraft measurements provide the only means of determining the radial (vertical) structure of the hard X-ray source. This potential of the multi-spacecraft observations is illustrated with an analysis of the presently available observations of solar hard X-ray bursts made simultaneously by two or more of the following spacecraft: International Sun Earth Explorer-3 (ISEE-3), Pioneer Venus Orbiter (PVO), Helios-B and High Energy Astrophysical Observatory-A (HEAO-A). In particular, some conclusions have been drawn about the spatial structure and directivity of 50-100 keV X-rays from impulsive flares. Desirable features of future multi-spacecraft missions are briefly discussed followed by a short description of the hard X-ray experiment on the International Solar Polar Mission which has been planned specifically for multi-spacecraft observations of the Sun. (orig.)

Multiple spacecraft observations of interplanetary shocks Four spacecraft determination of shock normals

Science.gov (United States)

Russell, C. T.; Mellott, M. M.; Smith, E. J.; King, J. H.

1983-01-01

ISEE 1, 2, 3, IMP 8, and Prognoz 7 observations of interplanetary shocks in 1978 and 1979 provide five instances where a single shock is observed by four spacecraft. These observations are used to determine best-fit normals for these five shocks. In addition to providing well-documented shocks for future investigations these data allow the evaluation of the accuracy of several shock normal determination techniques. When the angle between upstream and downstream magnetic field is greater than 20 deg, magnetic coplanarity can be an accurate single spacecraft method. However, no technique based solely on the magnetic measurements at one or multiple sites was universally accurate. Thus, the use of overdetermined shock normal solutions, utilizing plasma measurements, separation vectors, and time delays together with magnetic constraints, is recommended whenever possible.

Standardized spacecraft: a methodology for decision making. AMS report No. 1199

International Nuclear Information System (INIS)

Greenberg, J.S.; Nichols, R.A.

1974-01-01

As the space program matures, more and more attention is being focused on ways to reduce the costs of performing space missions. Standardization has been suggested as a way of providing cost reductions. The question of standardization at the system level, in particular, the question of the desirability of spacecraft standardization for geocentric space missions is addressed. The spacecraft is considered to be a bus upon which mission oriented equipment, the payload, is mounted. Three basic questions are considered: (1) is spacecraft standardization economically desirable; (2) if spacecraft standardization is economically desirable, what standardized spacecraft configuration or mix of configurations and technologies should be developed; and (3) if standardized spacecraft are to be developed, what power levels should they be designed for. A methodology which has been developed and which is necessary to follow if the above questions are to be answered and informed decisions made relative to spacecraft standardization is described. To illustrate the decision making problems and the need for the developed methodology and the data requirements, typical standardized spacecraft have been considered. Both standardized solar and nuclear-powered spacecraft and mission specialized spacecraft have been conceptualized and performance and cost estimates have been made. These estimates are not considered to be of sufficient accuracy to allow decisions regarding spacecraft mix and power levels to be made at this time. The estimates are deemed of sufficient accuracy so as to demonstrate the desirability of spacecraft standardization and the methodology (as well as the need for the methodology) which is necessary to decide upon the best mix of standardized spacecraft and their design power levels. (U.S.)

Spacecraft Material Outgassing Data

Data.gov (United States)

National Aeronautics and Space Administration — This compilation of outgassing data of materials intended for spacecraft use were obtained at the Goddard Space Flight Center (GSFC), utilizing equipment developed...

Planning Inmarsat's second generation of spacecraft

Science.gov (United States)

Williams, W. P.

1982-09-01

The next generation of studies of the Inmarsat service are outlined, such as traffic forecasting studies, communications capacity estimates, space segment design, cost estimates, and financial analysis. Traffic forecasting will require future demand estimates, and a computer model has been developed which estimates demand over the Atlantic, Pacific, and Indian ocean regions. Communications estimates are based on traffic estimates, as a model converts traffic demand into a required capacity figure for a given area. The Erlang formula is used, requiring additional data such as peak hour ratios and distribution estimates. Basic space segment technical requirements are outlined (communications payload, transponder arrangements, etc), and further design studies involve such areas as space segment configuration, launcher and spacecraft studies, transmission planning, and earth segment configurations. Cost estimates of proposed design parameters will be performed, but options must be reduced to make construction feasible. Finally, a financial analysis will be carried out in order to calculate financial returns.

Light Curve Simulation Using Spacecraft CAD Models and Empirical Material Spectral BRDFS

Science.gov (United States)

Willison, A.; Bedard, D.

This paper presents a Matlab-based light curve simulation software package that uses computer-aided design (CAD) models of spacecraft and the spectral bidirectional reflectance distribution function (sBRDF) of their homogenous surface materials. It represents the overall optical reflectance of objects as a sBRDF, a spectrometric quantity, obtainable during an optical ground truth experiment. The broadband bidirectional reflectance distribution function (BRDF), the basis of a broadband light curve, is produced by integrating the sBRDF over the optical wavelength range. Colour-filtered BRDFs, the basis of colour-filtered light curves, are produced by first multiplying the sBRDF by colour filters, and integrating the products. The software package's validity is established through comparison of simulated reflectance spectra and broadband light curves with those measured of the CanX-1 Engineering Model (EM) nanosatellite, collected during an optical ground truth experiment. It is currently being extended to simulate light curves of spacecraft in Earth orbit, using spacecraft Two-Line-Element (TLE) sets, yaw/pitch/roll angles, and observer coordinates. Measured light curves of the NEOSSat spacecraft will be used to validate simulated quantities. The sBRDF was chosen to represent material reflectance as it is spectrometric and a function of illumination and observation geometry. Homogeneous material sBRDFs were obtained using a goniospectrometer for a range of illumination and observation geometries, collected in a controlled environment. The materials analyzed include aluminum alloy, two types of triple-junction photovoltaic (TJPV) cell, white paint, and multi-layer insulation (MLI). Interpolation and extrapolation methods were used to determine the sBRDF for all possible illumination and observation geometries not measured in the laboratory, resulting in empirical look-up tables. These look-up tables are referenced when calculating the overall sBRDF of objects, where

Effects of soil stiffness and embedment on reactor building response

International Nuclear Information System (INIS)

Michalopoulos, A.P.; Vardanega, C.; Cornaggia, L.

1981-01-01

A parametric study was made to assess the influence of soil conditions and foundation embedment depth on the floor response spectra for a reactor building. The analyses incorporated soft, medium and hard soils, and three different embedment depths, in a seismic environment described by a 0.36 g peak ground acceleration. The shear wave velocity profiles for the soft, medium and hard soil conditions, were assumed to increase in proportion to the square root of depth from their ground surface values of 300, 600 and 900 meters per second, respectively. Foundation embedment depths of zero, eight and fourteen meters were analyzed using elastic half-space theory, accounting for kinematic interaction. The variation of shear modulus with depth under earthquake excitation was determined using a deconvolution process. Horizontal and vertical synthetic time histories, matching the USNRC Regulatory Guide 1.60 design ground response spectra, were applied at the ground surface and then deconvolved to the foundation level to obtain the input for the soil-structure model. The mathematical model of the superstructure consisted of four lumped-mass close-coupled systems, representing containment shells and components, while the foundation mat was modeled as rigid. Lumped soil compliances (springs and dashpots) were used to represent the horizontal, vertical and rotational modes of vibration. The dynamic analyses were performed utilizing the computer code DAPSYS, and consisted of mode frequency analyses and modal superposition. Modal damping was computed as a weighted average of structural and soil (radiation and material) damping, using the strain energy stored in the respective components as the weighting factor and distinguishing the hysteric nature of the structural and soil material damping, and the viscous nature of the soil radiation damping. (orig./RW)

High-Performance Fire Detector for Spacecraft, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — The danger from fire aboard spacecraft is immediate with only moments for detection and suppression. Spacecraft are unique high-value systems where the cost of...

Image Watermarking Scheme for Specifying False Positive Probability and Bit-pattern Embedding

Science.gov (United States)

Sayama, Kohei; Nakamoto, Masayoshi; Muneyasu, Mitsuji; Ohno, Shuichi

This paper treats a discrete wavelet transform(DWT)-based image watermarking with considering the false positive probability and bit-pattern embedding. We propose an iterative embedding algorithm of watermarking signals which are K sets pseudo-random numbers generated by a secret key. In the detection, K correlations between the watermarked DWT coefficients and watermark signals are computed by using the secret key. L correlations are made available for the judgment of the watermark presence with specified false positive probability, and the other K-L correlations are corresponding to the bit-pattern signal. In the experiment, we show the detection results with specified false positive probability and the bit-pattern recovery, and the comparison of the proposed method against JPEG compression, scaling down and cropping.

Electromagnetic Forces on a Relativistic Spacecraft in the Interstellar Medium

Energy Technology Data Exchange (ETDEWEB)

Hoang, Thiem [Korea Astronomy and Space Science Institute, Daejeon 34055 (Korea, Republic of); Loeb, Abraham, E-mail: thiemhoang@kasi.re.kr, E-mail: aloeb@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA (United States)

2017-10-10

A relativistic spacecraft of the type envisioned by the Breakthrough Starshot initiative will inevitably become charged through collisions with interstellar particles and UV photons. Interstellar magnetic fields would therefore deflect the trajectory of the spacecraft. We calculate the expected deflection for typical interstellar conditions. We also find that the charge distribution of the spacecraft is asymmetric, producing an electric dipole moment. The interaction between the moving electric dipole and the interstellar magnetic field is found to produce a large torque, which can result in fast oscillation of the spacecraft around the axis perpendicular to the direction of motion, with a period of ∼0.5 hr. We then study the spacecraft rotation arising from impulsive torques by dust bombardment. Finally, we discuss the effect of the spacecraft rotation and suggest several methods to mitigate it.

Spacecraft Fire Safety Demonstration

Data.gov (United States)

National Aeronautics and Space Administration — The objective of the Spacecraft Fire Safety Demonstration project is to develop and conduct large-scale fire safety experiments on an International Space Station...

Interactive learning environments to support independent learning: the impact of discernability of embedded support devices

NARCIS (Netherlands)

Martens, Rob; Valcke, Martin; Portier, Stanley

2017-01-01

In this article the effectivity of prototypes of interactive learning environments (ILE) is investigated. These computer-based environments are used for independent learning. In the learning materials, represented in the prototypes, a clear distinction is made between the basic content and embedded

Operational Philosophy Concerning Manned Spacecraft Cabin Leaks

Science.gov (United States)

DeSimpelaere, Edward

2011-01-01

The last thirty years have seen the Space Shuttle as the prime United States spacecraft for manned spaceflight missions. Many lessons have been learned about spacecraft design and operation throughout these years. Over the next few decades, a large increase of manned spaceflight in the commercial sector is expected. This will result in the exposure of commercial crews and passengers to many of the same risks crews of the Space Shuttle have encountered. One of the more dire situations that can be encountered is the loss of pressure in the habitable volume of the spacecraft during on orbit operations. This is referred to as a cabin leak. This paper seeks to establish a general cabin leak response philosophy with the intent of educating future spacecraft designers and operators. After establishing a relative definition for a cabin leak, the paper covers general descriptions of detection equipment, detection methods, and general operational methods for management of a cabin leak. Subsequently, all these items are addressed from the perspective of the Space Shuttle Program, as this will be of the most value to future spacecraft due to similar operating profiles. Emphasis here is placed upon why and how these methods and philosophies have evolved to meet the Space Shuttle s needs. This includes the core ideas of: considerations of maintaining higher cabin pressures vs. lower cabin pressures, the pros and cons of a system designed to feed the leak with gas from pressurized tanks vs. using pressure suits to protect against lower cabin pressures, timeline and consumables constraints, re-entry considerations with leaks of unknown origin, and the impact the International Space Station (ISS) has had to the standard Space Shuttle cabin leak response philosophy. This last item in itself includes: procedural management differences, hardware considerations, additional capabilities due to the presence of the ISS and its resource, and ISS docking/undocking considerations with a

Computer-Aided Transformation of PDE Models: Languages, Representations, and a Calculus of Operations

Science.gov (United States)

2016-01-05

Computer-aided transformation of PDE models: languages, representations, and a calculus of operations A domain-specific embedded language called...languages, representations, and a calculus of operations Report Title A domain-specific embedded language called ibvp was developed to model initial...Computer-aided transformation of PDE models: languages, representations, and a calculus of operations 1 Vision and background Physical and engineered systems

Iodine Plasma (Electric Propulsion) Interaction with Spacecraft Materials

Science.gov (United States)

2016-12-28

Teflon (AGT5, Ag-FEP) Thermal control surface (radiator) Spacecraft Exposure Soda-lime glass (74% SiO2 , 13% Na2O, 8% CaO, 4% MgO, 1% other oxide... Glass Solar panel cover Spacecraft Exposure Buna-N (acrylonitrile butadiene rubber) Seals Iodine Feed System Carbon fiber composite (epoxy resin...Fe Propellant isolator Spacecraft Exposure Lanthanum Hexaboride, LaB6 Cathode emitter Inside Cathode Yes MACOR (46% SiO2 , 17% MgO, 16% Al2O3, 10

Minimum curvilinearity to enhance topological prediction of protein interactions by network embedding

KAUST Repository

Cannistraci, Carlo

2013-06-21

Motivation: Most functions within the cell emerge thanks to protein-protein interactions (PPIs), yet experimental determination of PPIs is both expensive and time-consuming. PPI networks present significant levels of noise and incompleteness. Predicting interactions using only PPI-network topology (topological prediction) is difficult but essential when prior biological knowledge is absent or unreliable.Methods: Network embedding emphasizes the relations between network proteins embedded in a low-dimensional space, in which protein pairs that are closer to each other represent good candidate interactions. To achieve network denoising, which boosts prediction performance, we first applied minimum curvilinear embedding (MCE), and then adopted shortest path (SP) in the reduced space to assign likelihood scores to candidate interactions. Furthermore, we introduce (i) a new valid variation of MCE, named non-centred MCE (ncMCE); (ii) two automatic strategies for selecting the appropriate embedding dimension; and (iii) two new randomized procedures for evaluating predictions.Results: We compared our method against several unsupervised and supervisedly tuned embedding approaches and node neighbourhood techniques. Despite its computational simplicity, ncMCE-SP was the overall leader, outperforming the current methods in topological link prediction.Conclusion: Minimum curvilinearity is a valuable non-linear framework that we successfully applied to the embedding of protein networks for the unsupervised prediction of novel PPIs. The rationale for our approach is that biological and evolutionary information is imprinted in the non-linear patterns hidden behind the protein network topology, and can be exploited for predicting new protein links. The predicted PPIs represent good candidates for testing in high-throughput experiments or for exploitation in systems biology tools such as those used for network-based inference and prediction of disease-related functional modules. The

Experiments study on attitude coupling control method for flexible spacecraft

Science.gov (United States)

Wang, Jie; Li, Dongxu

2018-06-01

High pointing accuracy and stabilization are significant for spacecrafts to carry out Earth observing, laser communication and space exploration missions. However, when a spacecraft undergoes large angle maneuver, the excited elastic oscillation of flexible appendages, for instance, solar wing and onboard antenna, would downgrade the performance of the spacecraft platform. This paper proposes a coupling control method, which synthesizes the adaptive sliding mode controller and the positive position feedback (PPF) controller, to control the attitude and suppress the elastic vibration simultaneously. Because of its prominent performance for attitude tracking and stabilization, the proposed method is capable of slewing the flexible spacecraft with a large angle. Also, the method is robust to parametric uncertainties of the spacecraft model. Numerical simulations are carried out with a hub-plate system which undergoes a single-axis attitude maneuver. An attitude control testbed for the flexible spacecraft is established and experiments are conducted to validate the coupling control method. Both numerical and experimental results demonstrate that the method discussed above can effectively decrease the stabilization time and improve the attitude accuracy of the flexible spacecraft.

Analyzing the Risks Embedded in Option Prices with rndfittool

DEFF Research Database (Denmark)

Barletta, Andrea; Santucci de Magistris, Paolo

2018-01-01

This paper introduces a new computational tool for the analysis of the risks embedded in a set of prices of European-style options. The software enables the estimation of the risk-neutral density (RND) from the observed option prices by means of orthogonal polynomial expansions. Orthogonal...... polynomials offer a viable alternative to more standard techniques based on interpolation and estimation of the second-order derivatives of option prices. The app rndfittool is available on GitHub and its usage is illustrated with examples based on real data....

An embedded control and acquisition system for multichannel detectors

International Nuclear Information System (INIS)

Gori, L.; Tommasini, R.; Cautero, G.; Giuressi, D.; Barnaba, M.; Accardo, A.; Carrato, S.; Paolucci, G.

1999-01-01

We present a pulse counting multichannel data acquisition system, characterized by the high number of high speed acquisition channels, and by the modular, embedded system architecture. The former leads to very fast acquisitions and allows to obtain sequences of snapshots, for the study of time dependent phenomena. The latter, thanks to the integration of a CPU into the system, provides high computational capabilities, so that the interfacing with the user computer is very simple and user friendly. Moreover, the user computer is free from control and acquisition tasks. The system has been developed for one of the beamlines of the third generation synchrotron radiation sources ELETTRA, and because of the modular architecture can be useful in various other kinds of experiments, where parallel acquisition, high data rates, and user friendliness are required. First experimental results on a double pass hemispherical electron analyser provided with a 96 channel detector confirm the validity of the approach. (author)

Uranus: a rapid prototyping tool for FPGA embedded computer vision

Science.gov (United States)

Rosales-Hernández, Victor; Castillo-Jimenez, Liz; Viveros-Velez, Gilberto; Zuñiga-Grajeda, Virgilio; Treviño Torres, Abel; Arias-Estrada, M.

2007-01-01

The starting point for all successful system development is the simulation. Performing high level simulation of a system can help to identify, insolate and fix design problems. This work presents Uranus, a software tool for simulation and evaluation of image processing algorithms with support to migrate them to an FPGA environment for algorithm acceleration and embedded processes purposes. The tool includes an integrated library of previous coded operators in software and provides the necessary support to read and display image sequences as well as video files. The user can use the previous compiled soft-operators in a high level process chain, and code his own operators. Additional to the prototyping tool, Uranus offers FPGA-based hardware architecture with the same organization as the software prototyping part. The hardware architecture contains a library of FPGA IP cores for image processing that are connected with a PowerPC based system. The Uranus environment is intended for rapid prototyping of machine vision and the migration to FPGA accelerator platform, and it is distributed for academic purposes.

Enhanced performance of microfluidic soft pressure sensors with embedded solid microspheres

Science.gov (United States)

Shin, Hee-Sup; Ryu, Jaiyoung; Majidi, Carmel; Park, Yong-Lae

2016-02-01

The cross-sectional geometry of an embedded microchannel influences the electromechanical response of a soft microfluidic sensor to applied surface pressure. When a pressure is exerted on the surface of the sensor deforming the soft structure, the cross-sectional area of the embedded channel filled with a conductive fluid decreases, increasing the channel’s electrical resistance. This electromechanical coupling can be tuned by adding solid microspheres into the channel. In order to determine the influence of microspheres, we use both analytic and computational methods to predict the pressure responses of soft microfluidic sensors with two different channel cross-sections: a square and an equilateral triangular. The analytical models were derived from contact mechanics in which microspheres were regarded as spherical indenters, and finite element analysis (FEA) was used for simulation. For experimental validation, sensor samples with the two different channel cross-sections were prepared and tested. For comparison, the sensor samples were tested both with and without microspheres. All three results from the analytical models, the FEA simulations, and the experiments showed reasonable agreement confirming that the multi-material soft structure significantly improved its pressure response in terms of both linearity and sensitivity. The embedded solid particles enhanced the performance of soft sensors while maintaining their flexible and stretchable mechanical characteristic. We also provide analytical and experimental analyses of hysteresis of microfluidic soft sensors considering a resistive force to the shape recovery of the polymer structure by the embedded viscous fluid.

Employing Inquiry-Based Computer Simulations and Embedded Scientist Videos To Teach Challenging Climate Change and Nature of Science Concepts

Science.gov (United States)

Cohen, E.

2013-12-01

Design based research was utilized to investigate how students use a greenhouse effect simulation in order to derive best learning practices. During this process, students recognized the authentic scientific process involving computer simulations. The simulation used is embedded within an inquiry-based technology-mediated science curriculum known as Web-based Inquiry Science Environment (WISE). For this research, students from a suburban, diverse, middle school setting use the simulations as part of a two week-long class unit on climate change. A pilot study was conducted during phase one of the research that informed phase two, which encompasses the dissertation. During the pilot study, as students worked through the simulation, evidence of shifts in student motivation, understanding of science content, and ideas about the nature of science became present using a combination of student interviews, focus groups, and students' conversations. Outcomes of the pilot study included improvements to the pedagogical approach. Allowing students to do 'Extreme Testing' (e.g., making the world as hot or cold as possible) and increasing the time for free exploration of the simulation are improvements made as a result of the findings of the pilot study. In the dissertation (phase two of the research design) these findings were implemented in a new curriculum scaled for 85 new students from the same school during the next school year. The modifications included new components implementing simulations as an assessment tool for all students and embedded modeling tools. All students were asked to build pre and post models, however due to technological constraints these were not an effective tool. A non-video group of 44 students was established and another group of 41 video students had a WISE curriculum which included twelve minutes of scientists' conversational videos referencing explicit aspects on the nature of science, specifically the use of models and simulations in science

Implementation of density functional embedding theory within the projector-augmented-wave method and applications to semiconductor defect states

International Nuclear Information System (INIS)

Yu, Kuang; Libisch, Florian; Carter, Emily A.

2015-01-01

We report a new implementation of the density functional embedding theory (DFET) in the VASP code, using the projector-augmented-wave (PAW) formalism. Newly developed algorithms allow us to efficiently perform optimized effective potential optimizations within PAW. The new algorithm generates robust and physically correct embedding potentials, as we verified using several test systems including a covalently bound molecule, a metal surface, and bulk semiconductors. We show that with the resulting embedding potential, embedded cluster models can reproduce the electronic structure of point defects in bulk semiconductors, thereby demonstrating the validity of DFET in semiconductors for the first time. Compared to our previous version, the new implementation of DFET within VASP affords use of all features of VASP (e.g., a systematic PAW library, a wide selection of functionals, a more flexible choice of U correction formalisms, and faster computational speed) with DFET. Furthermore, our results are fairly robust with respect to both plane-wave and Gaussian type orbital basis sets in the embedded cluster calculations. This suggests that the density functional embedding method is potentially an accurate and efficient way to study properties of isolated defects in semiconductors

Embedded Linux projects using Yocto project cookbook

CERN Document Server

González, Alex

2015-01-01

If you are an embedded developer learning about embedded Linux with some experience with the Yocto project, this book is the ideal way to become proficient and broaden your knowledge with examples that are immediately applicable to your embedded developments. Experienced embedded Yocto developers will find new insight into working methodologies and ARM specific development competence.

Relative Attitude Estimation for a Uniform Motion and Slowly Rotating Noncooperative Spacecraft

Directory of Open Access Journals (Sweden)

Liu Zhang

2017-01-01

Full Text Available This paper presents a novel relative attitude estimation approach for a uniform motion and slowly rotating noncooperative spacecraft. It is assumed that the uniform motion and slowly rotating noncooperative chief spacecraft is in failure or out of control and there is no a priori rotation rate information. We utilize a very fast binary descriptor based on binary robust independent elementary features (BRIEF to obtain the features of the target, which are rotational invariance and resistance to noise. And then, we propose a novel combination of single candidate random sample consensus (RANSAC with extended Kalman filter (EKF that makes use of the available prior probabilistic information from the EKF in the RANSAC model hypothesis stage. The advantage of this combination obviously reduces the sample size to only one, which results in large computational savings without the loss of accuracy. Experimental results from real image sequence of a real model target show that the relative angular error is about 3.5% and the mean angular velocity error is about 0.1 deg/s.

Spacecraft 3D Augmented Reality Mobile App

Science.gov (United States)

Hussey, Kevin J.; Doronila, Paul R.; Kumanchik, Brian E.; Chan, Evan G.; Ellison, Douglas J.; Boeck, Andrea; Moore, Justin M.

2013-01-01

The Spacecraft 3D application allows users to learn about and interact with iconic NASA missions in a new and immersive way using common mobile devices. Using Augmented Reality (AR) techniques to project 3D renditions of the mission spacecraft into real-world surroundings, users can interact with and learn about Curiosity, GRAIL, Cassini, and Voyager. Additional updates on future missions, animations, and information will be ongoing. Using a printed AR Target and camera on a mobile device, users can get up close with these robotic explorers, see how some move, and learn about these engineering feats, which are used to expand knowledge and understanding about space. The software receives input from the mobile device's camera to recognize the presence of an AR marker in the camera's field of view. It then displays a 3D rendition of the selected spacecraft in the user's physical surroundings, on the mobile device's screen, while it tracks the device's movement in relation to the physical position of the spacecraft's 3D image on the AR marker.

Integrated analysis tools for trade studies of spacecraft controller and sensor locations

Science.gov (United States)

Rowell, L. F.

1986-01-01

The present investigation was conducted with the aim to evaluate the practicality and difficulties of modern control design methods for large space structure controls. The evaluation is used as a basis for the identification of useful computer-based analysis tools which would provide insight into control characteristics of a spacecraft concept. A description is presented of the wrap-rib antenna and its packaging concept. Attention is given to active control requirements, a mathematical model of structural dynamics, aspects of sensor and actuator location, the analysis approach, controllability, observability, the concept of balanced realization, transmission zeros, singular value plots, analysis results, model reduction, and an interactive computer program. It is pointed out that the application of selected control analysis tools to the wrap-rib antenna demonstrates several capabilities which can be useful during conceptual design.

An Embedded Database Application for the Aggregation of Farming Device Data

DEFF Research Database (Denmark)

Iftikhar, Nadeem; Pedersen, Torben Bach

2010-01-01

In order to store massive amounts of data produced by the farming devices and to keep data that spans long intervals of time for analysis, reporting and maintenance purposes; it is desirable to reduce the size of the data by maintaining the data at different aggregate levels. The older data can...... be made coarse-grained while keeping the newest data fine-grained. Considering the availability of a limited amount of storage capacity on the farm machinery, an application written in C was developed to collect the data from a CAN-BUS, store it into the embedded database efficiently and perform gradual...... data aggregation effectively. Furthermore, the aggregation is achieved by using either two ratio-based aggregation methods or a time-granularity based aggregation method. A detailed description of the embedded database technology on a tractor computer is also presented in this paper....

Optimal trajectories of aircraft and spacecraft

Science.gov (United States)

Miele, A.

1990-01-01

Work done on algorithms for the numerical solutions of optimal control problems and their application to the computation of optimal flight trajectories of aircraft and spacecraft is summarized. General considerations on calculus of variations, optimal control, numerical algorithms, and applications of these algorithms to real-world problems are presented. The sequential gradient-restoration algorithm (SGRA) is examined for the numerical solution of optimal control problems of the Bolza type. Both the primal formulation and the dual formulation are discussed. Aircraft trajectories, in particular, the application of the dual sequential gradient-restoration algorithm (DSGRA) to the determination of optimal flight trajectories in the presence of windshear are described. Both take-off trajectories and abort landing trajectories are discussed. Take-off trajectories are optimized by minimizing the peak deviation of the absolute path inclination from a reference value. Abort landing trajectories are optimized by minimizing the peak drop of altitude from a reference value. Abort landing trajectories are optimized by minimizing the peak drop of altitude from a reference value. The survival capability of an aircraft in a severe windshear is discussed, and the optimal trajectories are found to be superior to both constant pitch trajectories and maximum angle of attack trajectories. Spacecraft trajectories, in particular, the application of the primal sequential gradient-restoration algorithm (PSGRA) to the determination of optimal flight trajectories for aeroassisted orbital transfer are examined. Both the coplanar case and the noncoplanar case are discussed within the frame of three problems: minimization of the total characteristic velocity; minimization of the time integral of the square of the path inclination; and minimization of the peak heating rate. The solution of the second problem is called nearly-grazing solution, and its merits are pointed out as a useful

D-Move: A Mobile Communication Based Delphi for Digital Natives to Support Embedded Research

Science.gov (United States)

Petrovic, Otto

2017-01-01

Digital Natives are raised with computers and the Internet, which are a familiar part of their daily life. To gain insights into their attitude and behavior, methods and media for empirical research face new challenges like gamification, context oriented embedded research, integration of multiple data sources, and the increased importance of…

Scheduling of Fault-Tolerant Embedded Systems with Soft and Hard Timing Constraints

DEFF Research Database (Denmark)

Izosimov, Viacheslav; Pop, Paul; Eles, Petru

2008-01-01

In this paper we present an approach to the synthesis of fault-tolerant schedules for embedded applications with soft and hard real-time constraints. We are interested to guarantee the deadlines for the hard processes even in the case of faults, while maximizing the overall utility. We use time....../utility functions to capture the utility of soft processes. Process re-execution is employed to recover from multiple faults. A single static schedule computed off-line is not fault tolerant and is pessimistic in terms of utility, while a purely online approach, which computes a new schedule every time a process...

Trends in languages for embedded systems

International Nuclear Information System (INIS)

Boasson, M.

1986-01-01

Characteristics of embedded systems are discussed. In particular, the role of the computer in such systems is highlighted. Special emphasis is placed on the different requirements different kinds of systems may place on program execution. From such requirements necessary programming constructs are derived and in an overview of currently used languages it is shown how evolution led to modern languages like Ada and CHILL. With the advent of cheap, fast and small processing units, exploitation of parallelism for enhancing system performance is becoming increasingly tempting. However, few languages support the design of such multi-processor systems. Some methods for dealing with this problem are discussed. Finally, systems architectures and associated languages for the use of techniques originally developed for AI research are adumbrated. (Auth.)

Embedded processor extensions for image processing

Science.gov (United States)

Thevenin, Mathieu; Paindavoine, Michel; Letellier, Laurent; Heyrman, Barthélémy

2008-04-01

The advent of camera phones marks a new phase in embedded camera sales. By late 2009, the total number of camera phones will exceed that of both conventional and digital cameras shipped since the invention of photography. Use in mobile phones of applications like visiophony, matrix code readers and biometrics requires a high degree of component flexibility that image processors (IPs) have not, to date, been able to provide. For all these reasons, programmable processor solutions have become essential. This paper presents several techniques geared to speeding up image processors. It demonstrates that a gain of twice is possible for the complete image acquisition chain and the enhancement pipeline downstream of the video sensor. Such results confirm the potential of these computing systems for supporting future applications.

Wireless embedded control system for atomically precise manufacturing

KAUST Repository

Khan, Yasser; Randall, John N.

2011-01-01

This paper will explore the possibilities of implementing a wireless embedded control system for atomically precise manufacturing. The manufacturing process, similar to Scanning Tunneling Microscopy, takes place within an Ultra High Vacuum (UHV) chamber at a pressure of 10-10 torr. In order to create vibration isolation, and to keep internal noise to a minimum, a wireless link inside the UHV chamber becomes essential. We present a MATLAB simulation of the problem, and then demonstrate a hardware scheme between a Gumstix computer and a Linux based laptop for controlling nano-manipulators with three degrees of freedom. © 2011 IEEE.

Wireless embedded control system for atomically precise manufacturing

KAUST Repository

Khan, Yasser

2011-04-01

This paper will explore the possibilities of implementing a wireless embedded control system for atomically precise manufacturing. The manufacturing process, similar to Scanning Tunneling Microscopy, takes place within an Ultra High Vacuum (UHV) chamber at a pressure of 10-10 torr. In order to create vibration isolation, and to keep internal noise to a minimum, a wireless link inside the UHV chamber becomes essential. We present a MATLAB simulation of the problem, and then demonstrate a hardware scheme between a Gumstix computer and a Linux based laptop for controlling nano-manipulators with three degrees of freedom. © 2011 IEEE.

LDEF materials results for spacecraft applications: Executive summary

Science.gov (United States)

Whitaker, A. F.; Dooling, D.

1995-03-01

To address the challenges of space environmental effects, NASA designed the Long Duration Exposure Facility (LDEF) for an 18-month mission to expose thousands of samples of candidate materials that might be used on a space station or other orbital spacecraft. LDEF was launched in April 1984 and was to have been returned to Earth in 1985. Changes in mission schedules postponed retrieval until January 1990, after 69 months in orbit. Analyses of the samples recovered from LDEF have provided spacecraft designers and managers with the most extensive data base on space materials phenomena. Many LDEF samples were greatly changed by extended space exposure. Among even the most radially altered samples, NASA and its science teams are finding a wealth of surprising conclusions and tantalizing clues about the effects of space on materials. Many were discussed at the first two LDEF results conferences and subsequent professional papers. The LDEF Materials Results for Spacecraft Applications Conference was convened in Huntsville to discuss implications for spacecraft design. Already, paint and thermal blanket selections for space station and other spacecraft have been affected by LDEF data. This volume synopsizes those results.

3D Display of Spacecraft Dynamics Using Real Telemetry

Directory of Open Access Journals (Sweden)

Sanguk Lee

2002-12-01

Full Text Available 3D display of spacecraft motion by using telemetry data received from satellite in real-time is described. Telemetry data are converted to the appropriate form for 3-D display by the real-time preprocessor. Stored playback telemetry data also can be processed for the display. 3D display of spacecraft motion by using real telemetry data provides intuitive comprehension of spacecraft dynamics.

Numerical Analysis of Magnetic Sail Spacecraft

International Nuclear Information System (INIS)

Sasaki, Daisuke; Yamakawa, Hiroshi; Usui, Hideyuki; Funaki, Ikkoh; Kojima, Hirotsugu

2008-01-01

To capture the kinetic energy of the solar wind by creating a large magnetosphere around the spacecraft, magneto-plasma sail injects a plasma jet into a strong magnetic field produced by an electromagnet onboard the spacecraft. The aim of this paper is to investigate the effect of the IMF (interplanetary magnetic field) on the magnetosphere of magneto-plasma sail. First, using an axi-symmetric two-dimensional MHD code, we numerically confirm the magnetic field inflation, and the formation of a magnetosphere by the interaction between the solar wind and the magnetic field. The expansion of an artificial magnetosphere by the plasma injection is then simulated, and we show that the magnetosphere is formed by the interaction between the solar wind and the magnetic field expanded by the plasma jet from the spacecraft. This simulation indicates the size of the artificial magnetosphere becomes smaller when applying the IMF.

Evaluation of Transient Pin-Stress Requirements for Spacecraft Launching in Lightning Environments. Pain Free Analysis to Alleviate Those Pin Stress Headaches

Science.gov (United States)

Edwards, Paul; Terseck, Alex; Trout, Dawn

2016-01-01

Spacecraft are generally protected from direct lightning attachment by encapsulation within the payload fairing of a launch vehicle and the ground structures that exist at the launch site. Regardless of where lightning strikes, potentially damaging indirect effects prevail from the coupling of electromagnetic fields into a loop created by outer shield of the payload umbilical. The energy coupled into individual spacecraft circuits is dependent on the umbilical current drive, the cable transfer impedance and the source/ load circuitry, and the reference potential used. Lightning induced transient susceptibility of the spacecraft avionics needs to be fully understood in order to define realistic re-test criteria in the event of a lightning occurrence during the launch campaign. Use of standards such as RTCA/DO-160 & SAE 5412 has some applicability but do not represent the indirect environment adequately. This paper evaluates the launch pad environments, the measurement data available, and computer simulations to provide pain-free analysis to alleviate the transient pin-stress headaches for spacecraft launching in Lightning environments.

Quick spacecraft charging primer

International Nuclear Information System (INIS)

Larsen, Brian Arthur

2014-01-01

This is a presentation in PDF format which is a quick spacecraft charging primer, meant to be used for program training. It goes into detail about charging physics, RBSP examples, and how to identify charging.

K{sub I}-T estimation for embedded flaws in pipes - Part II: Circumferentially oriented cracks

Energy Technology Data Exchange (ETDEWEB)

Qian Xudong, E-mail: cveqx@nus.edu.s [Department of Civil Engineering, National University of Singapore, 1 Engineering Drive 2, Singapore 117576 (Singapore)

2010-04-15

This paper, in parallel to the investigation on axially embedded cracks reported in the companion paper, presents a numerical study on the linear-elastic K{sub I} and T-stress values over the front of elliptical cracks circumferentially embedded in the wall of a pipe/cylindrical structure, under a uniform pressure applied on the inner surface of the pipe. The numerical procedure employs the interaction-integral approach to compute the linear-elastic stress-intensity factor (SIF) K{sub I} and T-stress values for embedded cracks with practical sizes at different locations in the wall of the pipe. The parametric study covers a wide range of geometric parameters for embedded cracks in the pipe, including: the wall thickness to the inner radius ratio (t/R{sub i}), the crack depth over the wall thickness ratio (a/t), the crack aspect ratio (a/c) and the ratio of the distance from the centerline of the crack to the outer surface of the pipe over the pipe wall thickness (e{sub M}/t). The parametric investigation identifies a significant effect of the remaining ligament length on both the T-stress and K{sub I} values at the crack-front location (denoted by point O) nearest to the outer surface of the pipe and at the crack-front location (denoted by point I) nearest to the inner surface of the pipe. The numerical investigation establishes the database to derive approximate functions from a nonlinear curve-fitting procedure to predict the T-stress and K{sub I} values at three critical front locations of the circumferentially embedded crack in a pipe: points O, I and M. The proposed T-stress and K{sub I} functions utilize a combined second-order polynomial and a power-law expression, which presents a close agreement with the T-stress and K{sub I} values computed from the very detailed finite element models. The comparison between the circumferentially embedded crack and the axially embedded crack indicates that both the T-stress and K{sub I} values at crack-front points O and

Research on intelligent power distribution system for spacecraft

Science.gov (United States)

Xia, Xiaodong; Wu, Jianju

2017-10-01

The power distribution system (PDS) mainly realizes the power distribution and management of the electrical load of the whole spacecraft, which is directly related to the success or failure of the mission, and hence is an important part of the spacecraft. In order to improve the reliability and intelligent degree of the PDS, and considering the function and composition of spacecraft power distribution system, this paper systematically expounds the design principle and method of the intelligent power distribution system based on SSPC, and provides the analysis and verification of the test data additionally.

Terahertz Computed Tomography of NASA Thermal Protection System Materials

Science.gov (United States)

Roth, D. J.; Reyes-Rodriguez, S.; Zimdars, D. A.; Rauser, R. W.; Ussery, W. W.

2011-01-01

A terahertz axial computed tomography system has been developed that uses time domain measurements in order to form cross-sectional image slices and three-dimensional volume renderings of terahertz-transparent materials. The system can inspect samples as large as 0.0283 cubic meters (1 cubic foot) with no safety concerns as for x-ray computed tomography. In this study, the system is evaluated for its ability to detect and characterize flat bottom holes, drilled holes, and embedded voids in foam materials utilized as thermal protection on the external fuel tanks for the Space Shuttle. X-ray micro-computed tomography was also performed on the samples to compare against the terahertz computed tomography results and better define embedded voids. Limits of detectability based on depth and size for the samples used in this study are loosely defined. Image sharpness and morphology characterization ability for terahertz computed tomography are qualitatively described.

Bacterial filamentation accelerates colonization of adhesive spots embedded in biopassive surfaces

International Nuclear Information System (INIS)

Möller, Jens; Emge, Philippe; Vizcarra, Ima Avalos; Kollmannsberger, Philip; Vogel, Viola

2013-01-01

Sessile bacteria adhere to engineered surfaces and host tissues and pose a substantial clinical and economical risk when growing into biofilms. Most engineered and biological interfaces are of chemically heterogeneous nature and provide adhesive islands for bacterial attachment and growth. To mimic either defects in a surface coating of biomedical implants or heterogeneities within mucosal layers (Peyer's patches), we embedded micrometre-sized adhesive islands in a poly(ethylene glycol) biopassive background. We show experimentally and computationally that filamentation of Escherichia coli can significantly accelerate the bacterial surface colonization under physiological flow conditions. Filamentation can thus provide an advantage to a bacterial population to bridge non-adhesive distances exceeding 5 μm. Bacterial filamentation, caused by blocking of bacterial division, is common among bacterial species and can be triggered by environmental conditions or antibiotic treatment. While great awareness exists that the build-up of antibiotic resistance serves as intrinsic survival strategy, we show here that antibiotic treatment can actually promote surface colonization by triggering filamentation, which in turn prevents daughter cells from being washed away. Our combined microfabrication and computational approaches provide quantitative insights into mechanisms that enable biofouling of biopassive surfaces with embedded adhesive spots, even for spot distances that are multiples of the bacterial length. (paper)

Bacterial filamentation accelerates colonization of adhesive spots embedded in biopassive surfaces

Science.gov (United States)

Möller, Jens; Emge, Philippe; Avalos Vizcarra, Ima; Kollmannsberger, Philip; Vogel, Viola

2013-12-01

Sessile bacteria adhere to engineered surfaces and host tissues and pose a substantial clinical and economical risk when growing into biofilms. Most engineered and biological interfaces are of chemically heterogeneous nature and provide adhesive islands for bacterial attachment and growth. To mimic either defects in a surface coating of biomedical implants or heterogeneities within mucosal layers (Peyer's patches), we embedded micrometre-sized adhesive islands in a poly(ethylene glycol) biopassive background. We show experimentally and computationally that filamentation of Escherichia coli can significantly accelerate the bacterial surface colonization under physiological flow conditions. Filamentation can thus provide an advantage to a bacterial population to bridge non-adhesive distances exceeding 5 μm. Bacterial filamentation, caused by blocking of bacterial division, is common among bacterial species and can be triggered by environmental conditions or antibiotic treatment. While great awareness exists that the build-up of antibiotic resistance serves as intrinsic survival strategy, we show here that antibiotic treatment can actually promote surface colonization by triggering filamentation, which in turn prevents daughter cells from being washed away. Our combined microfabrication and computational approaches provide quantitative insights into mechanisms that enable biofouling of biopassive surfaces with embedded adhesive spots, even for spot distances that are multiples of the bacterial length.

Embedded multi-channel data acquisition system on FPGA for Aditya Tokamak

Energy Technology Data Exchange (ETDEWEB)

Rajpal, Rachana, E-mail: rachana@ipr.res.in [Institute for Plasma Research, Gandhinagar, Gujarat (India); Mandaliya, Hitesh, E-mail: hitesh@ipr.res.in [ITER, Cadarache (France); Patel, Jignesh, E-mail: jjp@ipr.res.in [ITER, Cadarache (France); Kumari, Praveena, E-mail: praveena@ipr.res.in [Institute for Plasma Research, Gandhinagar, Gujarat (India); Gautam, Pramila, E-mail: pramila@ipr.res.in [Institute for Plasma Research, Gandhinagar, Gujarat (India); Raulji, Vismaysinh, E-mail: vismay@ipr.res.in [Institute for Plasma Research, Gandhinagar, Gujarat (India); Edappala, Praveenlal, E-mail: praveen@ipr.res.in [Institute for Plasma Research, Gandhinagar, Gujarat (India); Pujara, H.D, E-mail: pujara@ipr.res [Institute for Plasma Research, Gandhinagar, Gujarat (India); Jha, R., E-mail: jha@ipr.res.in [Institute for Plasma Research, Gandhinagar, Gujarat (India)

2016-11-15

Highlights: • 64 channel data acquisition, interface to PC/104 bus, using single board computer. • Integration of all components in single hardware to make it standalone and portable. • Development of application software in Qt on Linux platform for better performance and low cost compared to Windows. • Explored and utilized FPGA resources for hardware interfacing. - Abstract: The 64 channel data acquisition board is designed to meet the future demand of acquisition channels for plasma diagnostics. The inherent features of the board are 16 bit resolution, programmable sampling rate upto 200 kS/s/ch and simultaneous acquisition. To make system embedded and compact, 8 Analog Inputs ADC chip, 4M × 16 bit RAM memory, Field Programmable Gate Arrays, PC/104 platform and single board computer are used. High speed timing control signals for all ADCs and RAMs are generated by FPGA. The system is standalone, portable and interface through Ethernet. The acquisition application is developed in Qt. on Linux platform, in SBC. Due to ethernet connectivity and onboard processing, system can be integrated into Aditya and SST-1 data acquisition system. The performance of hardware is tested on Linux and Windows Embedded OS. The paper describes design, hardware and software architecture, implementation and results of 64 channel DAQ system.

Embedded multi-channel data acquisition system on FPGA for Aditya Tokamak

International Nuclear Information System (INIS)

Rajpal, Rachana; Mandaliya, Hitesh; Patel, Jignesh; Kumari, Praveena; Gautam, Pramila; Raulji, Vismaysinh; Edappala, Praveenlal; Pujara, H.D; Jha, R.

2016-01-01

Highlights: • 64 channel data acquisition, interface to PC/104 bus, using single board computer. • Integration of all components in single hardware to make it standalone and portable. • Development of application software in Qt on Linux platform for better performance and low cost compared to Windows. • Explored and utilized FPGA resources for hardware interfacing. - Abstract: The 64 channel data acquisition board is designed to meet the future demand of acquisition channels for plasma diagnostics. The inherent features of the board are 16 bit resolution, programmable sampling rate upto 200 kS/s/ch and simultaneous acquisition. To make system embedded and compact, 8 Analog Inputs ADC chip, 4M × 16 bit RAM memory, Field Programmable Gate Arrays, PC/104 platform and single board computer are used. High speed timing control signals for all ADCs and RAMs are generated by FPGA. The system is standalone, portable and interface through Ethernet. The acquisition application is developed in Qt. on Linux platform, in SBC. Due to ethernet connectivity and onboard processing, system can be integrated into Aditya and SST-1 data acquisition system. The performance of hardware is tested on Linux and Windows Embedded OS. The paper describes design, hardware and software architecture, implementation and results of 64 channel DAQ system.

Researching into a MOOC Embedded Flipped Classroom Model for College English Reading and Writing Course

Science.gov (United States)

Xinying, Zhang

2017-01-01

There is obvious pressure for higher education institutions to undergo transformation now in China. Reflecting this, the computer and information technology give rise to the development of a Massive Open Online Course (MOOC) embedded flipped classroom. Flipped classroom approaches replace the traditional transmissive teaching with engaging…

Source Code Verification for Embedded Systems using Prolog

Directory of Open Access Journals (Sweden)

Frank Flederer

2017-01-01

Full Text Available System relevant embedded software needs to be reliable and, therefore, well tested, especially for aerospace systems. A common technique to verify programs is the analysis of their abstract syntax tree (AST. Tree structures can be elegantly analyzed with the logic programming language Prolog. Moreover, Prolog offers further advantages for a thorough analysis: On the one hand, it natively provides versatile options to efficiently process tree or graph data structures. On the other hand, Prolog's non-determinism and backtracking eases tests of different variations of the program flow without big effort. A rule-based approach with Prolog allows to characterize the verification goals in a concise and declarative way. In this paper, we describe our approach to verify the source code of a flash file system with the help of Prolog. The flash file system is written in C++ and has been developed particularly for the use in satellites. We transform a given abstract syntax tree of C++ source code into Prolog facts and derive the call graph and the execution sequence (tree, which then are further tested against verification goals. The different program flow branching due to control structures is derived by backtracking as subtrees of the full execution sequence. Finally, these subtrees are verified in Prolog. We illustrate our approach with a case study, where we search for incorrect applications of semaphores in embedded software using the real-time operating system RODOS. We rely on computation tree logic (CTL and have designed an embedded domain specific language (DSL in Prolog to express the verification goals.

Feature-based component model for design of embedded systems

Science.gov (United States)

Zha, Xuan Fang; Sriram, Ram D.

2004-11-01

An embedded system is a hybrid of hardware and software, which combines software's flexibility and hardware real-time performance. Embedded systems can be considered as assemblies of hardware and software components. An Open Embedded System Model (OESM) is currently being developed at NIST to provide a standard representation and exchange protocol for embedded systems and system-level design, simulation, and testing information. This paper proposes an approach to representing an embedded system feature-based model in OESM, i.e., Open Embedded System Feature Model (OESFM), addressing models of embedded system artifacts, embedded system components, embedded system features, and embedded system configuration/assembly. The approach provides an object-oriented UML (Unified Modeling Language) representation for the embedded system feature model and defines an extension to the NIST Core Product Model. The model provides a feature-based component framework allowing the designer to develop a virtual embedded system prototype through assembling virtual components. The framework not only provides a formal precise model of the embedded system prototype but also offers the possibility of designing variation of prototypes whose members are derived by changing certain virtual components with different features. A case study example is discussed to illustrate the embedded system model.

Power requirements for commercial communications spacecraft

Science.gov (United States)

Billerbeck, W. J.

1985-01-01

Historical data on commercial spacecraft power systems are presented and their power requirements to the growth of satellite communications channel usage are related. Some approaches for estimating future power requirements of this class of spacecraft through the year 2000 are proposed. The key technology drivers in satellite power systems are addressed. Several technological trends in such systems are described, focusing on the most useful areas for research and development of major subsystems, including solar arrays, energy storage, and power electronics equipment.

PELACAKAN DAN PENGENALAN WAJAH MENGGUNAKAN METODE EMBEDDED HIDDEN MARKOV MODELS

Directory of Open Access Journals (Sweden)

Arie Wirawan Margono

2004-01-01

Full Text Available Tracking and recognizing human face becomes one of the important research subjects nowadays, where it is applicable in security system like room access, surveillance, as well as searching for person identity in police database. Because of applying in security case, it is necessary to have robust system for certain conditions such as: background influence, non-frontal face pose of male or female in different age and race. The aim of this research is to develop software which combines human face tracking using CamShift algorithm and face recognition system using Embedded Hidden Markov Models. The software uses video camera (webcam for real-time input, video AVI for dynamic input, and image file for static input. The software uses Object Oriented Programming (OOP coding style with C++ programming language, Microsoft Visual C++ 6.0® compiler, and assisted by some libraries of Intel Image Processing Library (IPL and Intel Open Source Computer Vision (OpenCV. System testing shows that object tracking based on skin complexion using CamShift algorithm comes out well, for tracking of single or even two face objects at once. Human face recognition system using Embedded Hidden Markov Models method has reach accuracy percentage of 82.76%, using 341 human faces in database that consists of 31 individuals with 11 poses and 29 human face testers. Abstract in Bahasa Indonesia : Pelacakan dan pengenalan wajah manusia merupakan salah satu bidang yang cukup berkembang dewasa ini, dimana aplikasi dapat diterapkan dalam bidang keamanan (security system seperti ijin akses masuk ruangan, pengawasan lokasi (surveillance, maupun pencarian identitas individu pada database kepolisian. Karena diterapkan dalam kasus keamanan, dibutuhkan sistem yang handal terhadap beberapa kondisi, seperti: pengaruh latar belakang, pose wajah non-frontal terhadap pria maupun wanita dalam perbedaan usia dan ras. Tujuan penelitiam ini adalah untuk membuat perangkat lunak yang menggabungkan

Modeling SMAP Spacecraft Attitude Control Estimation Error Using Signal Generation Model

Science.gov (United States)

Rizvi, Farheen

2016-01-01

Two ground simulation software are used to model the SMAP spacecraft dynamics. The CAST software uses a higher fidelity model than the ADAMS software. The ADAMS software models the spacecraft plant, controller and actuator models, and assumes a perfect sensor and estimator model. In this simulation study, the spacecraft dynamics results from the ADAMS software are used as CAST software is unavailable. The main source of spacecraft dynamics error in the higher fidelity CAST software is due to the estimation error. A signal generation model is developed to capture the effect of this estimation error in the overall spacecraft dynamics. Then, this signal generation model is included in the ADAMS software spacecraft dynamics estimate such that the results are similar to CAST. This signal generation model has similar characteristics mean, variance and power spectral density as the true CAST estimation error. In this way, ADAMS software can still be used while capturing the higher fidelity spacecraft dynamics modeling from CAST software.

Formal model-based development for safety-critical embedded software

International Nuclear Information System (INIS)

Kim, Jin Hyun; Choi, Jin Young

2005-01-01

Safety-critical embedded software for nuclear I and C system is developed under the safety and reliability regulation. Programmable logic controller(PLC) is a computer system for instrumentation and control (I and C) system of nuclear power plants. PLC consists of various I and C logics in software, including real-time operating system (RTOS). Hence, errors related with RTOS should be detected and eliminated in development processes. Practically, the verification and validation for errors in RTOS is performed in test procedure, in which a lot of tasks for testing are embedded in RTOS and are running under a test environments. But the test process can not be enough to guarantee the safety and reliability of RTOS. Therefore, in this paper, we introduce to applying formal methods with the development of software for the PLC. We particularity apply formal methods to a development of RTOS for PLC, which is a safety critical level. In this development, we use the state charts of I-Logix to specify and verification and model checking to verify the specification

Formal model-based development for safety-critical embedded software

Energy Technology Data Exchange (ETDEWEB)

Kim, Jin Hyun; Choi, Jin Young [Korea University, seoul (Korea, Republic of)

2005-11-15

Safety-critical embedded software for nuclear I and C system is developed under the safety and reliability regulation. Programmable logic controller(PLC) is a computer system for instrumentation and control (I and C) system of nuclear power plants. PLC consists of various I and C logics in software, including real-time operating system (RTOS). Hence, errors related with RTOS should be detected and eliminated in development processes. Practically, the verification and validation for errors in RTOS is performed in test procedure, in which a lot of tasks for testing are embedded in RTOS and are running under a test environments. But the test process can not be enough to guarantee the safety and reliability of RTOS. Therefore, in this paper, we introduce to applying formal methods with the development of software for the PLC. We particularity apply formal methods to a development of RTOS for PLC, which is a safety critical level. In this development, we use the state charts of I-Logix to specify and verification and model checking to verify the specification.

ATLAS Simulation using Real Data: Embedding and Overlay

Science.gov (United States)

Haas, Andrew; ATLAS Collaboration

2017-10-01

For some physics processes studied with the ATLAS detector, a more accurate simulation in some respects can be achieved by including real data into simulated events, with substantial potential improvements in the CPU, disk space, and memory usage of the standard simulation configuration, at the cost of significant database and networking challenges. Real proton-proton background events can be overlaid (at the detector digitization output stage) on a simulated hard-scatter process, to account for pileup background (from nearby bunch crossings), cavern background, and detector noise. A similar method is used to account for the large underlying event from heavy ion collisions, rather than directly simulating the full collision. Embedding replaces the muons found in Z→μμ decays in data with simulated taus at the same 4-momenta, thus preserving the underlying event and pileup from the original data event. In all these cases, care must be taken to exactly match detector conditions (beamspot, magnetic fields, alignments, dead sensors, etc.) between the real data event and the simulation. We will discuss the status of these overlay and embedding techniques within ATLAS software and computing.

A Sampling Based Approach to Spacecraft Autonomous Maneuvering with Safety Specifications

Science.gov (United States)

Starek, Joseph A.; Barbee, Brent W.; Pavone, Marco

2015-01-01

This paper presents a methods for safe spacecraft autonomous maneuvering that leverages robotic motion-planning techniques to spacecraft control. Specifically the scenario we consider is an in-plan rendezvous of a chaser spacecraft in proximity to a target spacecraft at the origin of the Clohessy Wiltshire Hill frame. The trajectory for the chaser spacecraft is generated in a receding horizon fashion by executing a sampling based robotic motion planning algorithm name Fast Marching Trees (FMT) which efficiently grows a tree of trajectories over a set of probabillistically drawn samples in the state space. To enforce safety the tree is only grown over actively safe samples for which there exists a one-burn collision avoidance maneuver that circularizes the spacecraft orbit along a collision-free coasting arc and that can be executed under potential thrusters failures. The overall approach establishes a provably correct framework for the systematic encoding of safety specifications into the spacecraft trajectory generations process and appears amenable to real time implementation on orbit. Simulation results are presented for a two-fault tolerant spacecraft during autonomous approach to a single client in Low Earth Orbit.

Expressing Environment Assumptions and Real-time Requirements for a Distributed Embedded System with Shared Variables

DEFF Research Database (Denmark)

Tjell, Simon; Fernandes, João Miguel

2008-01-01

In a distributed embedded system, it is often necessary to share variables among its computing nodes to allow the distribution of control algorithms. It is therefore necessary to include a component in each node that provides the service of variable sharing. For that type of component, this paper...

Special Semaphore Scheme for UHF Spacecraft Communications

Science.gov (United States)

Butman, Stanley; Satorius, Edgar; Ilott, Peter

2006-01-01

A semaphore scheme has been devised to satisfy a requirement to enable ultrahigh- frequency (UHF) radio communication between a spacecraft descending from orbit to a landing on Mars and a spacecraft, in orbit about Mars, that relays communications between Earth and the lander spacecraft. There are also two subsidiary requirements: (1) to use UHF transceivers, built and qualified for operation aboard the spacecraft that operate with residual-carrier binary phase-shift-keying (BPSK) modulation at a selectable data rate of 8, 32, 128, or 256 kb/s; and (2) to enable low-rate signaling even when received signals become so weak as to prevent communication at the minimum BPSK rate of 8 kHz. The scheme involves exploitation of Manchester encoding, which is used in conjunction with residual-carrier modulation to aid the carrier-tracking loop. By choosing various sequences of 1s, 0s, or 1s alternating with 0s to be fed to the residual-carrier modulator, one would cause the modulator to generate sidebands at a fundamental frequency of 4 or 8 kHz and harmonics thereof. These sidebands would constitute the desired semaphores. In reception, the semaphores would be detected by a software demodulator.

Environmentally-induced discharge transient coupling to spacecraft

Science.gov (United States)

Viswanathan, R.; Barbay, G.; Stevens, N. J.

1985-01-01

The Hughes SCREENS (Space Craft Response to Environments of Space) technique was applied to generic spin and 3-axis stabilized spacecraft models. It involved the NASCAP modeling for surface charging and lumped element modeling for transients coupling into a spacecraft. A differential voltage between antenna and spun shelf of approx. 400 V and current of 12 A resulted from discharge at antenna for the spinner and approx. 3 kv and 0.3 A from a discharge at solar panels for the 3-axis stabilized Spacecraft. A typical interface circuit response was analyzed to show that the transients would couple into the Spacecraft System through ground points, which are most vulnerable. A compilation and review was performed on 15 years of available data from electron and ion current collection phenomena. Empirical models were developed to match data and compared with flight data of Pix-1 and Pix-2 mission. It was found that large space power systems would float negative and discharge if operated at or above 300 V. Several recommendations are given to improve the models and to apply them to large space systems.

INCREASE OF STABILITY AT JPEG COMPRESSION OF THE DIGITAL WATERMARKS EMBEDDED IN STILL IMAGES

Directory of Open Access Journals (Sweden)

V. A. Batura

2015-07-01

Full Text Available Subject of Research. The paper deals with creation and research of method for increasing stability at JPEG compressing of digital watermarks embedded in still images. Method. A new algorithm of digital watermarking for still images which embeds digital watermark into a still image via modification of frequency coefficients for Hadamard discrete transformation is presented. The choice of frequency coefficients for embedding of a digital watermark is based on existence of sharp change of their values after modification at the maximum compression of JPEG. The choice of blocks of pixels for embedding is based on the value of their entropy. The new algorithm was subjected to the analysis of resistance to an image compression, noising, filtration, change of size, color and histogram equalization. Elham algorithm possessing a good resistance to JPEG compression was chosen for comparative analysis. Nine gray-scale images were selected as objects for protection. Obscurity of the distortions embedded in them was defined on the basis of the peak value of a signal to noise ratio which should be not lower than 43 dB for obscurity of the brought distortions. Resistibility of embedded watermark was determined by the Pearson correlation coefficient, which value should not be below 0.5 for the minimum allowed stability. The algorithm of computing experiment comprises: watermark embedding into each test image by the new algorithm and Elham algorithm; introducing distortions to the object of protection; extracting of embedded information with its subsequent comparison with the original. Parameters of the algorithms were chosen so as to provide approximately the same level of distortions introduced into the images. Main Results. The method of preliminary processing of digital watermark presented in the paper makes it possible to reduce significantly the volume of information embedded in the still image. The results of numerical experiment have shown that the

Column generation algorithms for virtual network embedding in flexi-grid optical networks.

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Lin, Rongping; Luo, Shan; Zhou, Jingwei; Wang, Sheng; Chen, Bin; Zhang, Xiaoning; Cai, Anliang; Zhong, Wen-De; Zukerman, Moshe

2018-04-16

Network virtualization provides means for efficient management of network resources by embedding multiple virtual networks (VNs) to share efficiently the same substrate network. Such virtual network embedding (VNE) gives rise to a challenging problem of how to optimize resource allocation to VNs and to guarantee their performance requirements. In this paper, we provide VNE algorithms for efficient management of flexi-grid optical networks. We provide an exact algorithm aiming to minimize the total embedding cost in terms of spectrum cost and computation cost for a single VN request. Then, to achieve scalability, we also develop a heuristic algorithm for the same problem. We apply these two algorithms for a dynamic traffic scenario where many VN requests arrive one-by-one. We first demonstrate by simulations for the case of a six-node network that the heuristic algorithm obtains very close blocking probabilities to exact algorithm (about 0.2% higher). Then, for a network of realistic size (namely, USnet) we demonstrate that the blocking probability of our new heuristic algorithm is about one magnitude lower than a simpler heuristic algorithm, which was a component of an earlier published algorithm.

Three-dimensional analysis for piled raft machine foundation embedded in sand

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Mahmood Mahmood

2018-01-01

Full Text Available Three-dimensional analysis for the dynamic response of a piled raft foundation subjected to vertical vibration is presented in this study. The analysis considers several factors affecting the amplitude of displacement for deep foundation such as pile cap embedment, pile cap thickness, relative density of the sand and the boundary effect. A validation for an experimental piled raft model depending on a scale factor of (20 using at (Plaxis 3D computer program was performed. The sand is simulated using Mohr-Coloumb model while the concrete is simulated as linear elastic material. It has been found that embedding the pile cap in the soil and increasing its thickness lead to decrease the maximum amplitude of displacement. Furthermore, the predictions showed that increasing the distance between the foundation and the boundaries and increasing the relative density of the sand can significantly minimize the dynamic response of the foundation.

Designing Ubiquitous Computing to Enhance Children's Learning in Museums

Science.gov (United States)

Hall, T.; Bannon, L.

2006-01-01

In recent years, novel paradigms of computing have emerged, which enable computational power to be embedded in artefacts and in environments in novel ways. These developments may create new possibilities for using computing to enhance learning. This paper presents the results of a design process that set out to explore interactive techniques,…

Phylogenetic trees and Euclidean embeddings.

Science.gov (United States)

Layer, Mark; Rhodes, John A

2017-01-01

It was recently observed by de Vienne et al. (Syst Biol 60(6):826-832, 2011) that a simple square root transformation of distances between taxa on a phylogenetic tree allowed for an embedding of the taxa into Euclidean space. While the justification for this was based on a diffusion model of continuous character evolution along the tree, here we give a direct and elementary explanation for it that provides substantial additional insight. We use this embedding to reinterpret the differences between the NJ and BIONJ tree building algorithms, providing one illustration of how this embedding reflects tree structures in data.

Economic analysis of open space box model utilization in spacecraft

Science.gov (United States)

Mohammad, Atif F.; Straub, Jeremy

2015-05-01

It is a known fact that the amount of data about space that is stored is getting larger on an everyday basis. However, the utilization of Big Data and related tools to perform ETL (Extract, Transform and Load) applications will soon be pervasive in the space sciences. We have entered in a crucial time where using Big Data can be the difference (for terrestrial applications) between organizations underperforming and outperforming their peers. The same is true for NASA and other space agencies, as well as for individual missions and the highly-competitive process of mission data analysis and publication. In most industries, conventional opponents and new candidates alike will influence data-driven approaches to revolutionize and capture the value of Big Data archives. The Open Space Box Model is poised to take the proverbial "giant leap", as it provides autonomic data processing and communications for spacecraft. We can find economic value generated from such use of data processing in our earthly organizations in every sector, such as healthcare, retail. We also can easily find retailers, performing research on Big Data, by utilizing sensors driven embedded data in products within their stores and warehouses to determine how these products are actually used in the real world.

DET/MPS - THE GSFC ENERGY BALANCE PROGRAM, DIRECT ENERGY TRANSFER/MULTIMISSION SPACECRAFT MODULAR POWER SYSTEM (UNIX VERSION)

Science.gov (United States)

Jagielski, J. M.

1994-01-01

The DET/MPS programs model and simulate the Direct Energy Transfer and Multimission Spacecraft Modular Power System in order to aid both in design and in analysis of orbital energy balance. Typically, the DET power system has the solar array directly to the spacecraft bus, and the central building block of MPS is the Standard Power Regulator Unit. DET/MPS allows a minute-by-minute simulation of the power system's performance as it responds to various orbital parameters, focusing its output on solar array output and battery characteristics. While this package is limited in terms of orbital mechanics, it is sufficient to calculate eclipse and solar array data for circular or non-circular orbits. DET/MPS can be adjusted to run one or sequential orbits up to about one week, simulated time. These programs have been used on a variety of Goddard Space Flight Center spacecraft projects. DET/MPS is written in FORTRAN 77 with some VAX-type extensions. Any FORTRAN 77 compiler that includes VAX extensions should be able to compile and run the program with little or no modifications. The compiler must at least support free-form (or tab-delineated) source format and 'do do-while end-do' control structures. DET/MPS is available for three platforms: GSC-13374, for DEC VAX series computers running VMS, is available in DEC VAX Backup format on a 9-track 1600 BPI tape (standard distribution) or TK50 tape cartridge; GSC-13443, for UNIX-based computers, is available on a .25 inch streaming magnetic tape cartridge in UNIX tar format; and GSC-13444, for Macintosh computers running AU/X with either the NKR FORTRAN or AbSoft MacFORTRAN II compilers, is available on a 3.5 inch 800K Macintosh format diskette. Source code and test data are supplied. The UNIX version of DET requires 90K of main memory for execution. DET/MPS was developed in 1990. A/UX and Macintosh are registered trademarks of Apple Computer, Inc. VMS, DEC VAX and TK50 are trademarks of Digital Equipment Corporation. UNIX is a

IDE Support of String-Embedded Languages

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S. Grigorev

2014-01-01

Full Text Available Complex information systems are often implemented by using more than one programming language. Sometimes this variety takes a form of one host and one or few string-embedded languages. Textual representation of clauses in a string-embedded language is built at run time by a host program and then analyzed, compiled or interpreted by a dedicated runtime component (database, web browser etc. Most general-purpose programming languages may play the role of the host; one of the most evident examples of the string-embedded language is the dynamic SQL which was specified in ISO SQL standard and is supported by the majority of DBMS. Standard IDE functionality such as code completion or syntax highlighting can really helps the developers who use this technique. There are several tools providing this functionality, but they all process only one concrete string-embedded language and cannot be easily extended for supporting another language. We present a platform which allows to easily create tools for string-embedded language processing.

A feedback linearization approach to spacecraft control using momentum exchange devices. Ph.D. Thesis

Science.gov (United States)

Dzielski, John Edward

1988-01-01

Recent developments in the area of nonlinear control theory have shown how coordiante changes in the state and input spaces can be used with nonlinear feedback to transform certain nonlinear ordinary differential equations into equivalent linear equations. These feedback linearization techniques are applied to resolve two problems arising in the control of spacecraft equipped with control moment gyroscopes (CMGs). The first application involves the computation of rate commands for the gimbals that rotate the individual gyroscopes to produce commanded torques on the spacecraft. The second application is to the long-term management of stored momentum in the system of control moment gyroscopes using environmental torques acting on the vehicle. An approach to distributing control effort among a group of redundant actuators is described that uses feedback linearization techniques to parameterize sets of controls which influence a specified subsystem in a desired way. The approach is adapted for use in spacecraft control with double-gimballed gyroscopes to produce an algorithm that avoids problematic gimbal configurations by approximating sets of gimbal rates that drive CMG rotors into desirable configurations. The momentum management problem is stated as a trajectory optimization problem with a nonlinear dynamical constraint. Feedback linearization and collocation are used to transform this problem into an unconstrainted nonlinear program. The approach to trajectory optimization is fast and robust. A number of examples are presented showing applications to the proposed NASA space station.

Constraint Embedding for Vehicle Suspension Dynamics

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Jain Abhinandan

2016-06-01

Full Text Available The goal of this research is to achieve close to real-time dynamics performance for allowing auto-pilot in-the-loop testing of unmanned ground vehicles (UGV for urban as well as off-road scenarios. The overall vehicle dynamics performance is governed by the multibody dynamics model for the vehicle, the wheel/terrain interaction dynamics and the onboard control system. The topic of this paper is the development of computationally efficient and accurate dynamics model for ground vehicles with complex suspension dynamics. A challenge is that typical vehicle suspensions involve closed-chain loops which require expensive DAE integration techniques. In this paper, we illustrate the use the alternative constraint embedding technique to reduce the cost and improve the accuracy of the dynamics model for the vehicle.

Global embedding of fibre inflation models

Energy Technology Data Exchange (ETDEWEB)

Cicoli, Michele [Dipartimento di Fisica e Astronomia, Università di Bologna,via Irnerio 46, 40126 Bologna (Italy); INFN - Sezione di Bologna,viale Berti Pichat 6/2, 40127 Bologna (Italy); Abdus Salam ICTP,Strada Costiera 11, Trieste 34151 (Italy); Muia, Francesco [Rudolf Peierls Centre for Theoretical Physics, University of Oxford,1 Keble Rd., Oxford OX1 3NP (United Kingdom); Shukla, Pramod [Abdus Salam ICTP,Strada Costiera 11, Trieste 34151 (Italy)

2016-11-30

We present concrete embeddings of fibre inflation models in globally consistent type IIB Calabi-Yau orientifolds with closed string moduli stabilisation. After performing a systematic search through the existing list of toric Calabi-Yau manifolds, we find several examples that reproduce the minimal setup to embed fibre inflation models. This involves Calabi-Yau manifolds with h{sup 1,1}=3 which are K3 fibrations over a ℙ{sup 1} base with an additional shrinkable rigid divisor. We then provide different consistent choices of the underlying brane set-up which generate a non-perturbative superpotential suitable for moduli stabilisation and string loop corrections with the correct form to drive inflation. For each Calabi-Yau orientifold setting, we also compute the effect of higher derivative contributions and study their influence on the inflationary dynamics.