Science.gov

Sample records for aggregate packet arrival

  1. Estimation over Unreliable Communication Links without Arrival Information of Packet Losses

    NASA Astrophysics Data System (ADS)

    Ma, Xiao; Djouadi, Seddik M.; Kuruganti, Teja; Nutaro, James J.; Drira, Anis

    2009-03-01

    This paper considers the estimation of a linear stochastic discrete-time system through an unreliable network. Packet losses from the sensor to the estimator are assumed to follow a Bernoulli distribution, while information loss at any time is not assumed to be available at the receiver. A new estimator is derived from the Kalman filter by using the probability of packet arrivals. It is shown that the new estimator provides a good estimate under unreliable communications with packet losses. The estimator is used successfully in a Linear Quadratic Gaussian (LQG) controller to stabilize an inverted pendulum system and compared to the standard Kalman filter.

  2. The benefits of converged packet/TDM/DWDM switching in metro aggregation networks

    NASA Astrophysics Data System (ADS)

    Bar On, Dror; Voll, Stefan; Au-Yang, Robert

    2012-12-01

    Next generation metro aggregation systems are expected to use integrated lambda, circuit and packet switching platforms. We analyzed a typical Tier 1 aggregation scenario using a converged transport platform offering OTN, MPLS-TP and lambda switching. Vertical integration (multiple transport technologies) and horizontal integration (multiple service types) yielded about one third savings over a traditional L3 over DWDM approach. The number of wavelengths needed was roughly halved. The usage of hybrid interfaces which allow sharing the wavelength between OTN and MPLS services leads to additional savings which will increase as the line rate shifts from 10G to 40G and 100G.

  3. GUIDANCE PACKET.

    ERIC Educational Resources Information Center

    Modern Language Association of America, New York, NY.

    THIS PACKET PROVIDES VOCATIONAL AND ACADEMIC ADVICE TO THE LANGUAGE LEARNER AND USEFUL INFORMATION ABOUT LANGUAGE LEARNING TO TEACHERS, COUNSELORS, AND ADMINISTRATORS. THE DOCUMENTS, PUBLISHED FROM 1963 TO 1967, ARE--(1) "VOCATIONAL OPPORTUNITIES FOR FOREIGN LANGUAGE STUDENTS" BY GILBERT C. KETTELKAMP, (2) "ADVICE TO THE LANGUAGE LEARNER" BY…

  4. Information Packet.

    ERIC Educational Resources Information Center

    Cable Television Information Center, Washington, DC.

    Documents included in the packet are Federal Communications Commission (FCC) releases dealing with cable television and similar notices from other organizations. Among these are an interpretation of the FCC local origination decision of Dec. 9, 1974, explaining the repeal of the requirement that small cable systems originate programing while…

  5. Television Compression Algorithms And Transmission On Packet Networks

    NASA Astrophysics Data System (ADS)

    Brainard, R. C.; Othmer, J. H.

    1988-10-01

    Wide-band packet transmission is a subject of strong current interest. The transmission of compressed TV signals over such networks is possible with any quality level. There are some specific advantages in using packet networks for TV transmission. Namely, any fixed data rate can be chosen, or a variable data rate can be utilized. However, on the negative side packet loss must be considered and differential delay in packet arrival must be compensated. The possibility of packet loss has a strong influence on compression algorithm choice. Differential delay of packet arrival is a new problem in codec design. Some issues relevant to mutual design of the transmission networks and compression algorithms will be presented. An assumption is that the packet network will maintain packet sequence integrity. For variable-rate transmission, a reasonable definition of peak data rate is necessary. Rate constraints may be necessary to encourage instituting a variable-rate service on the networks. The charging algorithm for network use will have an effect on selection of compression algorithm. Some values of and procedures for implementing packet priorities are discussed. Packet length has only a second-order effect on packet-TV considerations. Some examples of a range of codecs for differing data rates and picture quality are given. These serve to illustrate sensitivities to the various characteristics of packet networks. Perhaps more important, we talk about what we do not know about the design of such systems.

  6. Extensible packet processing architecture

    DOEpatents

    Robertson, Perry J.; Hamlet, Jason R.; Pierson, Lyndon G.; Olsberg, Ronald R.; Chun, Guy D.

    2013-08-20

    A technique for distributed packet processing includes sequentially passing packets associated with packet flows between a plurality of processing engines along a flow through data bus linking the plurality of processing engines in series. At least one packet within a given packet flow is marked by a given processing engine to signify by the given processing engine to the other processing engines that the given processing engine has claimed the given packet flow for processing. A processing function is applied to each of the packet flows within the processing engines and the processed packets are output on a time-shared, arbitered data bus coupled to the plurality of processing engines.

  7. A Packet Discarding Method with Two Parametrers

    NASA Astrophysics Data System (ADS)

    Fujii, Atsuro; Inai, Hiroshi

    In order to avoid congestion in the network and to achieve a fair share of the resource among communication flows, the packet discarding method called RED (Random Early Detection) has been proposed. In that method, a router randomly discards arriving packets before its buffer overflows. Although some enhanced methods of RED have been proposed, they employ complicated controls to achieve high throughput and fairness among communication flows. However, many control parameters in the complicated methods would prevent from reaching their practical stages. This paper proposes a simple packet discarding method which reduces the number of parameters and provides better performance than existing ones. Concretely speaking, our method omits the probabilistic packet discard from RED. Via simulation, the proposed method provides higher throughput than existing ones and almost equal fairness.

  8. Nonspreading Wave Packets.

    ERIC Educational Resources Information Center

    Berry, M. V.; Balazs, N. L.

    1979-01-01

    Explains properties of the Airy packet that show that quantum wave functions correspond to a family of orbits and not to a single particle. Introducing the Airy packet into elementary quantum mechanics courses is recommended. (HM)

  9. Packet Transport Technologies for Optical Networks

    NASA Astrophysics Data System (ADS)

    Lometti, Alberto; Busi, Italo; Grandi, Pietro; Sestito, Vincenzo; Paparella, Andrea

    The purpose of a transport network is to provide a reliable aggregation and transport infrastructure for any client traffic type, in any scale, at the lowest cost per bit. With the growth of packet services, operators are transforming their network infrastructures while looking at reducing capital expenditures and maximizing operational savings. In that scope, new technologies are emerging such as transport multi-protocol label switching and provider backbone transport. This article outlines the state of the art for packet-based transport technologies, comparing them and highlighting the key factors.

  10. New Teachers Packet.

    ERIC Educational Resources Information Center

    Journalism Education Association.

    This packet of information for new scholastic journalism teachers (or advisers) compiles information on professional associations in journalism education, offers curriculum guides and general help, and contains worksheets and handouts. Sections of the packet are: (1) Professional Help (Journalism Education Association Information, and Other…

  11. Quantum wave packet revivals

    NASA Astrophysics Data System (ADS)

    Robinett, R. W.

    2004-03-01

    The numerical prediction, theoretical analysis, and experimental verification of the phenomenon of wave packet revivals in quantum systems has flourished over the last decade and a half. Quantum revivals are characterized by initially localized quantum states which have a short-term, quasi-classical time evolution, which then can spread significantly over several orbits, only to reform later in the form of a quantum revival in which the spreading reverses itself, the wave packet relocalizes, and the semi-classical periodicity is once again evident. Relocalization of the initial wave packet into a number of smaller copies of the initial packet (‘minipackets’ or ‘clones’) is also possible, giving rise to fractional revivals. Systems exhibiting such behavior are a fundamental realization of time-dependent interference phenomena for bound states with quantized energies in quantum mechanics and are therefore of wide interest in the physics and chemistry communities. We review the theoretical machinery of quantum wave packet construction leading to the existence of revivals and fractional revivals, in systems with one (or more) quantum number(s), as well as discussing how information on the classical period and revival time is encoded in the energy eigenvalue spectrum. We discuss a number of one-dimensional model systems which exhibit revival behavior, including the infinite well, the quantum bouncer, and others, as well as several two-dimensional integrable quantum billiard systems. Finally, we briefly review the experimental evidence for wave packet revivals in atomic, molecular, and other systems, and related revival phenomena in condensed matter and optical systems.

  12. Hoover Dam Learning Packet.

    ERIC Educational Resources Information Center

    Bureau of Reclamation (Dept. of Interior), Washington, DC.

    This learning packet provides background information about Hoover Dam (Nevada) and the surrounding area. Since the dam was built at the height of the Depression in 1931, people came from all over the country to work on it. Because of Hoover Dam, the Colorado River was controlled for the first time in history and farmers in Nevada, California, and…

  13. PROGRAMMED LEARNING PACKET.

    ERIC Educational Resources Information Center

    Modern Language Association of America, New York, NY.

    MATERIALS CONCERNING PROGRAMED INSTRUCTION IN FOREIGN LANGUAGES, PUBLISHED FROM 1960 TO 1967, ARE COLLECTED IN THIS PACKET FOR LANGUAGE TEACHERS AND PERSONS INTERESTED IN THE FUTURE USES OF THE LANGUAGE LABORATORY. INCLUDED ARE--(1) "PROGRAMED LEARNING OF A SECOND LANGUAGE" BY HARLAN LANE, (2) "A PRIMER OF PROGRAMED INSTRUCTION IN FOREIGN LANGUAGE…

  14. Amelia Earhart Learning Packet.

    ERIC Educational Resources Information Center

    Civil Air Patrol, Maxwell AFB, AL.

    The feats of individuals who have made history in the aerospace world are often misunderstood and soon ignored or forgotten after the first notoriety has been achieved. Amelia Earhart was selected as the subject for this learning packet because of her brilliant accomplishments on the world of flight, a persistent desire to determine what really…

  15. Predictive onboard flow control for packet switching satellites

    NASA Technical Reports Server (NTRS)

    Bobinsky, Eric A.

    1992-01-01

    We outline two alternate approaches to predicting the onset of congestion in a packet switching satellite, and argue that predictive, rather than reactive, flow control is necessary for the efficient operation of such a system. The first method discussed is based on standard, statistical techniques which are used to periodically calculate a probability of near-term congestion based on arrival rate statistics. If this probability exceeds a present threshold, the satellite would transmit a rate-reduction signal to all active ground stations. The second method discussed would utilize a neural network to periodically predict the occurrence of buffer overflow based on input data which would include, in addition to arrival rates, the distributions of packet lengths, source addresses, and destination addresses.

  16. Predictive onboard flow control in packet switching satellites

    NASA Technical Reports Server (NTRS)

    Bobinsky, E. A.

    1992-01-01

    We outline two alternate approaches to predicting the onset of congestion in a packet switching satellite, and argue that predictive, rather than reactive, flow control is necessary for the efficient operation of such a system. The first method discussed is based on standard, statistical techniques which are used to periodically calculate a probability of near-term congestion based on arrival rate statistics. If this probability exceeds a present threshold, the satellite would transmit a rate-reduction signal to all active ground stations. The second method discussed would utilize a neural network to periodically predict the occurrence of buffer overflow based on input data which would include, in addition to arrival rates, the distributions of packet lengths, source addresses, and destination addresses.

  17. Packet Daemon Version 12(SOPHIA)

    SciTech Connect

    2012-08-09

    Packet Daemon Version 12 is the code exclusively used by the ‘packetd’ executable. It provides packet data to the OglNet Version 12 visualization tool. It reads PCAP data and sends an abstraction of the packets to the ‘oglnet’ executable for display. ‘packetd’will run as a service on a Linux host thereby capturing data continuously and make that data available for ‘oglnet’ whenever it connects to the service.

  18. Controlled Quantum Packets

    NASA Technical Reports Server (NTRS)

    DeMartino, Salvatore; DeSiena, Silvio

    1996-01-01

    We look at time evolution of a physical system from the point of view of dynamical control theory. Normally we solve motion equation with a given external potential and we obtain time evolution. Standard examples are the trajectories in classical mechanics or the wave functions in Quantum Mechanics. In the control theory, we have the configurational variables of a physical system, we choose a velocity field and with a suited strategy we force the physical system to have a well defined evolution. The evolution of the system is the 'premium' that the controller receives if he has adopted the right strategy. The strategy is given by well suited laboratory devices. The control mechanisms are in many cases non linear; it is necessary, namely, a feedback mechanism to retain in time the selected evolution. Our aim is to introduce a scheme to obtain Quantum wave packets by control theory. The program is to choose the characteristics of a packet, that is, the equation of evolution for its centre and a controlled dispersion, and to give a building scheme from some initial state (for example a solution of stationary Schroedinger equation). It seems natural in this view to use stochastic approach to Quantum Mechanics, that is, Stochastic Mechanics [S.M.]. It is a quantization scheme different from ordinary ones only formally. This approach introduces in quantum theory the whole mathematical apparatus of stochastic control theory. Stochastic Mechanics, in our view, is more intuitive when we want to study all the classical-like problems. We apply our scheme to build two classes of quantum packets both derived generalizing some properties of coherent states.

  19. Charles A. Lindbergh Learning Packet.

    ERIC Educational Resources Information Center

    Rodriguez, Charley

    This aerospace education learning packet contains information about the famous pilot, Charles A. Lindbergh. Posters, recommended teaching methods, tests with keys, and task cards are also included. (KHR)

  20. Separated Fringe Packet Binaries

    NASA Astrophysics Data System (ADS)

    Bagnuolo, W. G.; Taylor, S. F.; McAlister, H. A.; ten Brummelaar, T.; Sturmann, L.; Sturmann, J.; Turner, N. H.; Berger, D.; Ridgway, S. T.; CenterHigh Angular Resolution Astronomy (CHARA)

    2004-12-01

    Individually resolved packets are produced by scans from the CHARA Interferometer Array for binary stars with separations from 10 to 100 milli-arcsec (mas) in the K' band. We have used this data for astrometry of the binary with the goal of improving the visual orbits for these systems. About 12 data sets of 400 scans each can be collected for a star within an hour. The intrinsic accuracy with simple linear/quadratic fits to the time-separation curve yields accuracies of 0.15 mas. But, for systems with separations less than 80 mas, the measured separation is modulated periodically by the secondary star's packet riding over the sidelobes of the primary which provides a phase reference. This "sidelobe verniering" can improve the precision to better than 50 micro-arcsec. These techniques, represents 1-2 orders of magnitude improvement in astrometic accuracy over speckle interferometry techniques. Visual orbits can then be refined via a maximum liklihood technique, which leads to revisions in the stellar masses. We present the results for several binaries that have been observed at the CHARA Array, starting in 2001.

  1. Pulsar Signal Denoising Method Based on Laplace Distribution in No-subsampling Wavelet Packet Domain

    NASA Astrophysics Data System (ADS)

    Wenbo, Wang; Yanchao, Zhao; Xiangli, Wang

    2016-11-01

    In order to improve the denoising effect of the pulsar signal, a new denoising method is proposed in the no-subsampling wavelet packet domain based on the local Laplace prior model. First, we count the true noise-free pulsar signal’s wavelet packet coefficient distribution characteristics and construct the true signal wavelet packet coefficients’ Laplace probability density function model. Then, we estimate the denosied wavelet packet coefficients by using the noisy pulsar wavelet coefficients based on maximum a posteriori criteria. Finally, we obtain the denoisied pulsar signal through no-subsampling wavelet packet reconstruction of the estimated coefficients. The experimental results show that the proposed method performs better when calculating the pulsar time of arrival than the translation-invariant wavelet denoising method.

  2. On quantization of nondispersive wave packets

    SciTech Connect

    Altaisky, M. V.

    2013-10-15

    Nondispersive wave packets are widely used in optics and acoustics. We found it interesting that such packets could be also a subject of quantum field theory. Canonical commutation relations for the nondispersive wave packets are constructed.

  3. Vocational and Industrial Arts Packets.

    ERIC Educational Resources Information Center

    Maine Audubon Society, Falmouth.

    This book is a teacher's guide to energy alternatives. It is divided into seven informational packets on the following topics: parabolic solar concentrators, solar flat plate collectors, wood as fuel, heat loss, bio-gas, wind, and water. Each packet contains background information for the teachers and learning activities for the students. The…

  4. USDA's Great Nutrition Adventure [Packet].

    ERIC Educational Resources Information Center

    Department of Agriculture, Washington, DC.

    This nutrition education packet provides information to schools setting up healthy school meal programs and nutrition education programs. Team Nutrition schools will involve students, teachers, families, food service personnel, and community organizations in nutrition education activities. The packet contains fact sheets that focus on: the Great…

  5. Tropical Animal Tour Packet. Metro.

    ERIC Educational Resources Information Center

    Metro Washington Park Zoo, Portland, OR. Educational Services Div.

    This packet is designed to assist teachers in creating a tropical animals lesson plan that centers around a visit to the zoo. A teacher packet is divided into eight parts: (1) goals and objectives; (2) what to expect at the zoo; (3) student activities (preparatory activities, on-site activities, and follow-up activities); (4) background…

  6. Experience with the EURECA Packet Telemetry and Packet Telecommand system

    NASA Technical Reports Server (NTRS)

    Sorensen, Erik Mose; Ferri, Paolo

    1994-01-01

    The European Retrieval Carrier (EURECA) was launched on its first flight on the 31st of July 1992 and retrieved on the 29th of June 1993. EURECA is characterized by several new on-board features, most notably Packet telemetry, and a partial implementation of packet telecommanding, the first ESA packetised spacecraft. Today more than one year after the retrieval the data from the EURECA mission has to a large extent been analysed and we can present some of the interesting results. This paper concentrates on the implementation and operational experience with the EURECA Packet Telemetry and Packet Telecommanding. We already discovered during the design of the ground system that the use of packet telemetry has major impact on the overall design and that processing of packet telemetry may have significant effect on the computer loading and sizing. During the mission a number of problems were identified with the on-board implementation resulting in very strange anomalous behaviors. Many of these problems directly violated basic assumptions for the design of the ground segment adding to the strange behavior. The paper shows that the design of a telemetry packet system should be flexible enough to allow a rapid configuration of the telemetry processing in order to adapt it to the new situation in case of an on-board failure. The experience gained with the EURECA mission control should be used to improve ground systems for future missions.

  7. High speed packet switching

    NASA Technical Reports Server (NTRS)

    1991-01-01

    This document constitutes the final report prepared by Proteon, Inc. of Westborough, Massachusetts under contract NAS 5-30629 entitled High-Speed Packet Switching (SBIR 87-1, Phase 2) prepared for NASA-Greenbelt, Maryland. The primary goal of this research project is to use the results of the SBIR Phase 1 effort to develop a sound, expandable hardware and software router architecture capable of forwarding 25,000 packets per second through the router and passing 300 megabits per second on the router's internal busses. The work being delivered under this contract received its funding from three different sources: the SNIPE/RIG contract (Contract Number F30602-89-C-0014, CDRL Sequence Number A002), the SBIR contract, and Proteon. The SNIPE/RIG and SBIR contracts had many overlapping requirements, which allowed the research done under SNIPE/RIG to be applied to SBIR. Proteon funded all of the work to develop new router interfaces other than FDDI, in addition to funding the productization of the router itself. The router being delivered under SBIR will be a fully product-quality machine. The work done during this contract produced many significant findings and results, summarized here and explained in detail in later sections of this report. The SNIPE/RIG contract was completed. That contract had many overlapping requirements with the SBIR contract, and resulted in the successful demonstration and delivery of a high speed router. The development that took place during the SNIPE/RIG contract produced findings that included the choice of processor and an understanding of the issues surrounding inter processor communications in a multiprocessor environment. Many significant speed enhancements to the router software were made during that time. Under the SBIR contract (and with help from Proteon-funded work), it was found that a single processor router achieved a throughput significantly higher than originally anticipated. For this reason, a single processor router was

  8. Threatened and Endangered Species: Tour Packet.

    ERIC Educational Resources Information Center

    Coats, Victoria; Samia, Cory

    This resource unit contains a teacher information packet and a middle school student activity packet to be used in creating a threatened and endangered species unit. The packet of student activities is designed to help maximize a field trip to the zoo and build on students' zoo experience in the classroom. The teacher information packet covers the…

  9. Overview of wideband packet protocols

    NASA Astrophysics Data System (ADS)

    Sherif, M. H.

    1992-10-01

    Wideband packet networks operate at rates equal to, or higher than, 64 kb/s, but lower than the basic broadband rate of 150 Mb/s, on cables or satellite links. Wideband packet protocols are the transmission protocols for these networks. They define open interfaces that can be used for public and private ISDNs. The protocols are defined in CCITT Recommendations G.764 and G.765. This paper describes the objectives of the wideband protocols, and how the objectives were achieved.

  10. Packet flow monitoring tool and method

    DOEpatents

    Thiede, David R [Richland, WA

    2009-07-14

    A system and method for converting packet streams into session summaries. Session summaries are a group of packets each having a common source and destination internet protocol (IP) address, and, if present in the packets, common ports. The system first captures packets from a transport layer of a network of computer systems, then decodes the packets captured to determine the destination IP address and the source IP address. The system then identifies packets having common destination IP addresses and source IP addresses, then writes the decoded packets to an allocated memory structure as session summaries in a queue.

  11. Bohmian trajectories of Airy packets

    NASA Astrophysics Data System (ADS)

    Nassar, Antonio B.; Miret-Artés, Salvador

    2014-09-01

    The discovery of Berry and Balazs in 1979 that the free-particle Schrödinger equation allows a non-dispersive and accelerating Airy-packet solution has taken the folklore of quantum mechanics by surprise. Over the years, this intriguing class of wave packets has sparked enormous theoretical and experimental activities in related areas of optics and atom physics. Within the Bohmian mechanics framework, we present new features of Airy wave packet solutions to Schrödinger equation with time-dependent quadratic potentials. In particular, we provide some insights to the problem by calculating the corresponding Bohmian trajectories. It is shown that by using general space-time transformations, these trajectories can display a unique variety of cases depending upon the initial position of the individual particle in the Airy wave packet. Further, we report here a myriad of nontrivial Bohmian trajectories associated to the Airy wave packet. These new features are worth introducing to the subject's theoretical folklore in light of the fact that the evolution of a quantum mechanical Airy wave packet governed by the Schrödinger equation is analogous to the propagation of a finite energy Airy beam satisfying the paraxial equation. Numerous experimental configurations of optics and atom physics have shown that the dynamics of Airy beams depends significantly on initial parameters and configurations of the experimental set-up.

  12. Bohmian trajectories of Airy packets

    SciTech Connect

    Nassar, Antonio B.; Miret-Artés, Salvador

    2014-09-15

    The discovery of Berry and Balazs in 1979 that the free-particle Schrödinger equation allows a non-dispersive and accelerating Airy-packet solution has taken the folklore of quantum mechanics by surprise. Over the years, this intriguing class of wave packets has sparked enormous theoretical and experimental activities in related areas of optics and atom physics. Within the Bohmian mechanics framework, we present new features of Airy wave packet solutions to Schrödinger equation with time-dependent quadratic potentials. In particular, we provide some insights to the problem by calculating the corresponding Bohmian trajectories. It is shown that by using general space–time transformations, these trajectories can display a unique variety of cases depending upon the initial position of the individual particle in the Airy wave packet. Further, we report here a myriad of nontrivial Bohmian trajectories associated to the Airy wave packet. These new features are worth introducing to the subject’s theoretical folklore in light of the fact that the evolution of a quantum mechanical Airy wave packet governed by the Schrödinger equation is analogous to the propagation of a finite energy Airy beam satisfying the paraxial equation. Numerous experimental configurations of optics and atom physics have shown that the dynamics of Airy beams depends significantly on initial parameters and configurations of the experimental set-up.

  13. Arrival Metering Precision Study

    NASA Technical Reports Server (NTRS)

    Prevot, Thomas; Mercer, Joey; Homola, Jeffrey; Hunt, Sarah; Gomez, Ashley; Bienert, Nancy; Omar, Faisal; Kraut, Joshua; Brasil, Connie; Wu, Minghong, G.

    2015-01-01

    This paper describes the background, method and results of the Arrival Metering Precision Study (AMPS) conducted in the Airspace Operations Laboratory at NASA Ames Research Center in May 2014. The simulation study measured delivery accuracy, flight efficiency, controller workload, and acceptability of time-based metering operations to a meter fix at the terminal area boundary for different resolution levels of metering delay times displayed to the air traffic controllers and different levels of airspeed information made available to the Time-Based Flow Management (TBFM) system computing the delay. The results show that the resolution of the delay countdown timer (DCT) on the controllers display has a significant impact on the delivery accuracy at the meter fix. Using the 10 seconds rounded and 1 minute rounded DCT resolutions resulted in more accurate delivery than 1 minute truncated and were preferred by the controllers. Using the speeds the controllers entered into the fourth line of the data tag to update the delay computation in TBFM in high and low altitude sectors increased air traffic control efficiency and reduced fuel burn for arriving aircraft during time based metering.

  14. A scheme for synchronizing clocks connected by a packet communication network

    NASA Astrophysics Data System (ADS)

    dos Santos, R. V.; Monteiro, L. H. A.

    2012-07-01

    Consider a communication system in which a transmitter equipment sends fixed-size packets of data at a uniform rate to a receiver equipment. Consider also that these equipments are connected by a packet-switched network, which introduces a random delay to each packet. Here we propose an adaptive clock recovery scheme able of synchronizing the frequencies and the phases of these devices, within specified limits of precision. This scheme for achieving frequency and phase synchronization is based on measurements of the packet arrival times at the receiver, which are used to control the dynamics of a digital phase-locked loop. The scheme performance is evaluated via numerical simulations performed by using realistic parameter values.

  15. Greedy data transportation scheme with hard packet deadlines for wireless ad hoc networks.

    PubMed

    Lee, HyungJune

    2014-01-01

    We present a greedy data transportation scheme with hard packet deadlines in ad hoc sensor networks of stationary nodes and multiple mobile nodes with scheduled trajectory path and arrival time. In the proposed routing strategy, each stationary ad hoc node en route decides whether to relay a shortest-path stationary node toward destination or a passing-by mobile node that will carry closer to destination. We aim to utilize mobile nodes to minimize the total routing cost as far as the selected route can satisfy the end-to-end packet deadline. We evaluate our proposed routing algorithm in terms of routing cost, packet delivery ratio, packet delivery time, and usability of mobile nodes based on network level simulations. Simulation results show that our proposed algorithm fully exploits the remaining time till packet deadline to turn into networking benefits of reducing the overall routing cost and improving packet delivery performance. Also, we demonstrate that the routing scheme guarantees packet delivery with hard deadlines, contributing to QoS improvement in various network services.

  16. Self-Interfering Wave Packets

    NASA Astrophysics Data System (ADS)

    Colas, David; Laussy, Fabrice P.

    2016-01-01

    We study the propagation of noninteracting polariton wave packets. We show how two qualitatively different concepts of mass that arise from the peculiar polariton dispersion lead to a new type of particlelike object from noninteracting fields—much like self-accelerating beams—shaped by the Rabi coupling out of Gaussian initial states. A divergence and change of sign of the diffusive mass results in a "mass wall" on which polariton wave packets bounce back. Together with the Rabi dynamics, this yields propagation of ultrafast subpackets and ordering of a spacetime crystal.

  17. Self-Interfering Wave Packets.

    PubMed

    Colas, David; Laussy, Fabrice P

    2016-01-15

    We study the propagation of noninteracting polariton wave packets. We show how two qualitatively different concepts of mass that arise from the peculiar polariton dispersion lead to a new type of particlelike object from noninteracting fields-much like self-accelerating beams-shaped by the Rabi coupling out of Gaussian initial states. A divergence and change of sign of the diffusive mass results in a "mass wall" on which polariton wave packets bounce back. Together with the Rabi dynamics, this yields propagation of ultrafast subpackets and ordering of a spacetime crystal. PMID:26824554

  18. Sports Medicine. Clinical Rotation. Instructor's Packet and Student Study Packet.

    ERIC Educational Resources Information Center

    Texas Univ., Austin. Extension Instruction and Materials Center.

    The materials in this packet are for a course designed to provide individualized classroom study for a specific area of clinical rotation--sports medicine. The instructor's manual describes the learning objectives together with a list of reference materials that should be provided for completion of the student worksheets, and lists suggested…

  19. Environment Resource Packets Get Wide Use

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1974

    1974-01-01

    Announces the availability of the resource packet entitled "Noise Pollution," the third in the series prepared by the University of Maryland, and the main topics which will be covered in the remaining three packets. (CC)

  20. A robust coding scheme for packet video

    NASA Technical Reports Server (NTRS)

    Chen, Y. C.; Sayood, Khalid; Nelson, D. J.

    1991-01-01

    We present a layered packet video coding algorithm based on a progressive transmission scheme. The algorithm provides good compression and can handle significant packet loss with graceful degradation in the reconstruction sequence. Simulation results for various conditions are presented.

  1. A robust coding scheme for packet video

    NASA Technical Reports Server (NTRS)

    Chen, Yun-Chung; Sayood, Khalid; Nelson, Don J.

    1992-01-01

    A layered packet video coding algorithm based on a progressive transmission scheme is presented. The algorithm provides good compression and can handle significant packet loss with graceful degradation in the reconstruction sequence. Simulation results for various conditions are presented.

  2. Homelessness: A General Information Packet.

    ERIC Educational Resources Information Center

    Homelessness Exchange, Washington, DC.

    This packet contains documents that provide general information about homelessness and the need for both Federal and local action to help the homeless people in America. Sections 1 and 2 contain the following articles released by the Homelessness Information Exchange: (1) "The Problem of Homelessness Nationwide"; and "Alternative Family Housing…

  3. Dynamics of quantum wave packets

    SciTech Connect

    Gosnell, T.R.; Taylor, A.J.; Rodriguez, G.; Clement, T.S.

    1998-11-01

    This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The objective of this project was to develop ultrafast laser techniques for the creation and measurement of quantum vibrational wave packets in gas phase diatomic molecules. Moreover, the authors sought to manipulate the constitution of these wave packets in terms of harmonic-oscillator basis wavefunctions by manipulating the time-dependent amplitude and phase of the incident ultrashort laser pulse. They specifically investigated gaseous diatomic potassium (K{sub 2}), and discovered variations in the shape of the wave packets as a result of changing the linear chirp in the ultrashort preparation pulse. In particular, they found evidence for wave-packet compression for a specific degree of chirp. Important ancillary results include development of new techniques for denoising and deconvolution of femtosecond time traces and techniques for diagnosing the phase and amplitude of the electric field of femtosecond laser pulses.

  4. Population and Development [Issue Packet].

    ERIC Educational Resources Information Center

    American Freedom from Hunger Foundation, Washington, DC.

    A variety of informational materials is compiled in this issue packet concentrating on population and development. The materials have been assembled to understand the issues associated with the facts of the world's population and to try to invent new forms of action and thought necessary to find the possibilities hidden in the population issue.…

  5. Dissection & Science Fairs. [Information Packet.

    ERIC Educational Resources Information Center

    National Anti-Vivisection Society, Chicago, IL.

    This collection of pamphlets and articles reprinted from other National Anti-Vivisection Society (NAVS) publications was compiled to address the issues of classroom laboratory dissection and the use of animals in science fair projects. Three of the pamphlets contained in this packet are student handbooks designed to help students of elementary,…

  6. Hunger and Development [Issue Packet].

    ERIC Educational Resources Information Center

    American Freedom from Hunger Foundation, Washington, DC.

    A variety of informational materials is compiled in this issue packet concentrating on hunger and development. They have been assembled to understand the issues associated with the facts of world hunger and to try to invent new forms of action and thought necessary to find the possibilities hidden in the hunger issue. Items include: (1) a fact and…

  7. Recycling Study Guide [Resource Packet].

    ERIC Educational Resources Information Center

    Wisconsin State Dept. of Natural Resources, Madison.

    This resource packet contains six documents developed by the Wisconsin Department of Natural Resources in order to help teachers infuse the environmental education topics of recycling and solid waste into social studies, art, English, health, mathematics, science, and environmental education classes. "Recycling Study Guide" contains 19 activities…

  8. Ancient Chinese Bronzes: Teacher's Packet.

    ERIC Educational Resources Information Center

    Smithsonian Institution, Washington, DC. Arthur M. Sackler Gallery.

    The focus of this teacher's packet is the bronze vessels made for the kings and great families of the early Chinese dynasties between 1700 B.C. and 200 A.D. The materials in the guide are intended for use by teachers and students visiting the exhibition, "The Arts of China," at the Arthur M. Sackler Gallery of the Smithsonian Institution in…

  9. 78 FR 63228 - Determination That Potassium Citrate, 10 Milliequivalents/Packet and 20 Milliequivalents/Packet...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-10-23

    ... HUMAN SERVICES Food and Drug Administration Determination That Potassium Citrate, 10 Milliequivalents...) has determined that Potassium Citrate, 10 milliequivalents/packet (mEq/packet) and 20 mEq/ packet, was... approve abbreviated new drug applications (ANDAs) for Potassium Citrate, 10 mEq/packet and 20...

  10. Packet Radio: An Alternative Way to Connect.

    ERIC Educational Resources Information Center

    Lucas, Larry W.

    1995-01-01

    Explains packet radio as a form of telecomputing in which digital data is transported via radio waves instead of telephone lines or other cabling, and describes how it can be used by students to access the Internet. Highlights include packet bulletin board systems and equipment needed for a packet radio station. (LRW)

  11. [KIND Worksheet Packet: Wild Animals (Junior).

    ERIC Educational Resources Information Center

    National Association for Humane and Environmental Education, East Haddam, CT.

    This packet is the junior part of a series of worksheet packets available at both junior (grades 3-4) and senior (grades 5-6) levels that covers a variety of humane and environmental topics. Each packet includes 10 worksheets, all of which originally appeared in past issues of the annual teaching magazine "KIND (Kids in Nature's Defense) Teacher."…

  12. Trade Related Reading Packets for Disabled Readers.

    ERIC Educational Resources Information Center

    Davis, Beverly; Woodruff, Nancy S.

    Six trade-related reading packets for disabled readers are provided for these trades: assemblers, baking, building maintenance, data entry, interior landscaping, and warehousing. Each packet stresses from 9 to 14 skills. Those skills common to most packets include context clues, fact or opinion, details, following directions, main idea,…

  13. [KIND Worksheet Packet: Wild Animals (Senior).

    ERIC Educational Resources Information Center

    National Association for Humane and Environmental Education, East Haddam, CT.

    This packet is the senior part of a series of worksheet packets available at both junior (grades 3-4) and senior (grades 5-6) levels that covers a variety of humane and environmental topics. Each packet includes 10 worksheets, all of which originally appeared in past issues of the annual teaching magazine "KIND (Kids in Nature's Defense) Teacher."…

  14. On-board closed-loop congestion control for satellite based packet switching networks

    NASA Technical Reports Server (NTRS)

    Chu, Pong P.; Ivancic, William D.; Kim, Heechul

    1993-01-01

    NASA LeRC is currently investigating a satellite architecture that incorporates on-board packet switching capability. Because of the statistical nature of packet switching, arrival traffic may fluctuate and thus it is necessary to integrate congestion control mechanism as part of the on-board processing unit. This study focuses on the closed-loop reactive control. We investigate the impact of the long propagation delay on the performance and propose a scheme to overcome the problem. The scheme uses a global feedback signal to regulate the packet arrival rate of ground stations. In this scheme, the satellite continuously broadcasts the status of its output buffer and the ground stations respond by selectively discarding packets or by tagging the excessive packets as low-priority. The two schemes are evaluated by theoretical queuing analysis and simulation. The former is used to analyze the simplified model and to determine the basic trends and bounds, and the later is used to assess the performance of a more realistic system and to evaluate the effectiveness of more sophisticated control schemes. The results show that the long propagation delay makes the closed-loop congestion control less responsive. The broadcasted information can only be used to extract statistical information. The discarding scheme needs carefully-chosen status information and reduction function, and normally requires a significant amount of ground discarding to reduce the on-board packet loss probability. The tagging scheme is more effective since it tolerates more uncertainties and allows a larger margin of error in status information. It can protect the high-priority packets from excessive loss and fully utilize the downlink bandwidth at the same time.

  15. The effect of human rhythm on packet delivery

    NASA Astrophysics Data System (ADS)

    Zhou, Zhao; Huang, Zi-Gang; Yang, Lei; Xue, De-Sheng; Wang, Ying-Hai

    2010-08-01

    In communication networks such as the Internet, the relationship between packet generation rate and time is similar to a rectangle wavefunction due to the rhythm of humans. Thus, we investigate the traffic dynamics on a network with a rectangle wavepacket generation rate. It is found that the critical delivering capacity parameter βc (which separates the congested phase and the free phase) decreases significantly with the duty cycle r of the rectangle wave for package generation. And, in the congested phase, more collective generation of packets (smaller r) is helpful for decreasing the packet aggregation rate. Moreover, it is found that the congested phase can be divided into two regions, i.e., region 1 and region 2, where the distributions of queue lengths are nonlinear and linear, respectively. Also, the linear expression for the distribution of queue lengths in region 2 is obtained analytically. Our work reveals an obvious effect of the rectangle wave on the traffic dynamics and the queue length distribution in the system, which is of essential interest and may provide insights into the designing of work-rest schedules and routing strategies.

  16. Group-normalized wavelet packet signal processing

    NASA Astrophysics Data System (ADS)

    Shi, Zhuoer; Bao, Zheng

    1997-04-01

    Since the traditional wavelet and wavelet packet coefficients do not exactly represent the strength of signal components at the very time(space)-frequency tilling, group- normalized wavelet packet transform (GNWPT), is presented for nonlinear signal filtering and extraction from the clutter or noise, together with the space(time)-frequency masking technique. The extended F-entropy improves the performance of GNWPT. For perception-based image, soft-logic masking is emphasized to remove the aliasing with edge preserved. Lawton's method for complex valued wavelets construction is extended to generate the complex valued compactly supported wavelet packets for radar signal extraction. This kind of wavelet packets are symmetry and unitary orthogonal. Well-defined wavelet packets are chosen by the analysis remarks on their time-frequency characteristics. For real valued signal processing, such as images and ECG signal, the compactly supported spline or bi- orthogonal wavelet packets are preferred for perfect de- noising and filtering qualities.

  17. Ingestion of Laundry Detergent Packets in Children.

    PubMed

    Shah, Lindsey Wilson

    2016-08-01

    Ingestion of laundry detergent packets is an important threat to young children. Because of their developmental stage, toddlers are prone to place these small, colorful packets in their mouths. The packets can easily burst, sending a large volume of viscous, alkaline liquid throughout the oropharynx. Ingestion causes major toxic effects, including depression of the central nervous system, metabolic acidosis, respiratory distress, and dysphagia. Critical care nurses should anticipate these clinical effects and facilitate prompt intervention. Increased understanding of the risks and clinical effects of ingestion of laundry detergent packets will better prepare critical care nurses to provide care for these children. (Critical Care Nurse 2016; 36[4]:70-75).

  18. Ingestion of Laundry Detergent Packets in Children.

    PubMed

    Shah, Lindsey Wilson

    2016-08-01

    Ingestion of laundry detergent packets is an important threat to young children. Because of their developmental stage, toddlers are prone to place these small, colorful packets in their mouths. The packets can easily burst, sending a large volume of viscous, alkaline liquid throughout the oropharynx. Ingestion causes major toxic effects, including depression of the central nervous system, metabolic acidosis, respiratory distress, and dysphagia. Critical care nurses should anticipate these clinical effects and facilitate prompt intervention. Increased understanding of the risks and clinical effects of ingestion of laundry detergent packets will better prepare critical care nurses to provide care for these children. (Critical Care Nurse 2016; 36[4]:70-75). PMID:27481804

  19. Oral Hygiene. Instructor's Packet. Learning Activity Package.

    ERIC Educational Resources Information Center

    Hime, Kirsten

    This instructor's packet accompanies the learning activity package (LAP) on oral hygiene. Contents included in the packet are a time sheet, suggested uses for the LAP, an instruction sheet, final LAP reviews, a final LAP review answer key, suggested activities, additional resources (student handouts), student performance checklists for both…

  20. Grooming. Instructor's Packet. Learning Activity Package.

    ERIC Educational Resources Information Center

    Stark, Pamela

    This instructor's packet accompanies the learning activity package (LAP) on grooming. Contents included in the packet are a time sheet, suggested uses for the LAP, an instruction sheet, final LAP reviews, a final LAP review answer key, suggested activities, an additional resources list, and student completion cards to issue to students as an…

  1. Handwashing Technique. Instructor's Packet. Learning Activity Package.

    ERIC Educational Resources Information Center

    Stark, Pamela

    This instructor's packet accompanies the learning activity package (LAP) on handwashing. Contents included in the packet are a time sheet, suggested uses for the LAP, an instruction sheet, final LAP reviews, a final LAP review answer key, a student performance checklist, an additional resources list, and student completion cards to issue to…

  2. Construction aggregates

    USGS Publications Warehouse

    Tepordei, V.V.

    1995-01-01

    Part of the 1994 Industrial Minerals Review. The production, consumption, and applications of construction aggregates are reviewed. In 1994, the production of construction aggregates, which includes crushed stone and construction sand and gravel combined, increased 7.7 percent to 2.14 Gt compared with the previous year. These record production levels are mostly a result of funding for highway construction work provided by the Intermodal Surface Transportation Efficiency Act of 1991. Demand is expected to increase for construction aggregates in 1995.

  3. Packet Traffic Dynamics Near Onset of Congestion in Data Communication Network Model

    NASA Astrophysics Data System (ADS)

    Lawniczak, A. T.; Tang, X.

    2006-05-01

    The dominant technology of data communication networks is the Packet Switching Network (PSN). It is a complex technology organized as various hierarchical layers according to the International Standard Organization (ISO) Open Systems Interconnect (OSI) Reference Model. The Network Layer of the ISO OSI Reference Model is responsible for delivering packets from their sources to their destinations and for dealing with congestion if it arises in a network. Thus, we focus on this layer and present an abstraction of the Network Layer of the ISO OSI Reference Model. Using this abstraction we investigate how onset of traffic congestion is affected for various routing algorithms by changes in network connection topology. We study how aggregate measures of network performance depend on network connection topology and routing. We explore packets traffic spatio-temporal dynamics near the phase transition point from free flow to congestion for various network connection topologies and routing algorithms. We consider static and adaptive routings. We present selected simulation results.

  4. Bad data packet capture device

    DOEpatents

    Chen, Dong; Gara, Alan; Heidelberger, Philip; Vranas, Pavlos

    2010-04-20

    An apparatus and method for capturing data packets for analysis on a network computing system includes a sending node and a receiving node connected by a bi-directional communication link. The sending node sends a data transmission to the receiving node on the bi-directional communication link, and the receiving node receives the data transmission and verifies the data transmission to determine valid data and invalid data and verify retransmissions of invalid data as corresponding valid data. A memory device communicates with the receiving node for storing the invalid data and the corresponding valid data. A computing node communicates with the memory device and receives and performs an analysis of the invalid data and the corresponding valid data received from the memory device.

  5. Experiments examining drag in linear droplet packets

    NASA Astrophysics Data System (ADS)

    Nguyen, Q. V.; Dunn-Rankin, D.

    1992-01-01

    This paper presents an experimental study of vertically traveling droplet packets, where the droplets in each packet are aligned linearly, one behind another. The paper describes in detail, an experimental apparatus that produces repeatable, linearly aligned, and isolated droplet packets containing 1 6 droplets per packet. The apparatus is suitable for examining aerodynamic interactions between droplets within each packet. This paper demonstrates the performance of the apparatus by examining the drag reduction and collision of droplets traveling in the wake of a lead droplet. Comparison of a calculated single droplet trajectory with the detailed droplet position versus time data for a droplet packet provides the average drag reduction experienced by the trailing droplets due to the aerodynamic wake of the lead droplet. For the conditions of our experiment (4 droplet packet, 145 μm methanol droplets, 10 m/s initial velocity, initial droplet spacing of 5.2 droplet diameters, Reynolds number approx. 80) the average drag on the first trailing droplet was found to be 75% of the drag on the lead droplet.

  6. Operator-normalized quantum arrival times in the presence of interactions

    SciTech Connect

    Hegerfeldt, G.C.; Seidel, D.; Muga, J.G.; Navarro, B.

    2004-07-01

    We model ideal arrival-time measurements for free quantum particles and for particles subject to an external interaction by means of a narrow and weak absorbing potential. This approach is related to the operational approach of measuring the first photon emitted from a two-level atom illuminated by a laser. By operator normalizing the resulting time-of-arrival distribution, a distribution is obtained which for freely moving particles not only recovers the axiomatically derived distribution of Kijowski for states with purely positive momenta but is also applicable to general momentum components. For particles interacting with a square barrier the mean arrival time and corresponding 'tunneling time' obtained at the transmission side of the barrier become independent of the barrier width (Hartman effect) for arbitrarily wide barriers, i.e., without the transition to the ultraopaque, classical-like regime dominated by wave packet components above the barrier.

  7. Interconnecting network for switching data packets and method for switching data packets

    DOEpatents

    Benner, Alan Frederic; Minkenberg, Cyriel Johan Agnes; Stunkel, Craig Brian

    2010-05-25

    The interconnecting network for switching data packets, having data and flow control information, comprises a local packet switch element (S1) with local input buffers (I(1,1) . . . I(1,y)) for buffering the incoming data packets, a remote packet switch element (S2) with remote input buffers (I(2,1) . . . I(2,y)) for buffering the incoming data packets, and data lines (L) for interconnecting the local and the remote packet switch elements (S1, S2). The interconnecting network further comprises a local and a remote arbiter (A1, A2) which are connected via control lines (CL) to the input buffers (I(1,1) . . . I(1,y), I(2,1) . . . I(2,y)), and which are formed such that they can provide that the flow control information is transmitted via the data lines (L) and the control lines (CL).

  8. Construction aggregates

    USGS Publications Warehouse

    Langer, W.H.; Tepordei, V.V.; Bolen, W.P.

    2000-01-01

    Construction aggregates consist primarily of crushed stone and construction sand and gravel. Total estimated production of construction aggregates increased in 1999 by about 2% to 2.39 Gt (2.64 billion st) compared with 1998. This record production level continued an expansion that began in 1992. By commodities, crushed stone production increased 3.3%, while sand and gravel production increased by about 0.5%.

  9. Construction aggregates

    USGS Publications Warehouse

    Tepordei, V.V.

    1994-01-01

    Part of a special section on industrial minerals in 1993. The 1993 production of construction aggregates increased 6.3 percent over the 1992 figure, to reach 2.01 Gt. This represents the highest estimated annual production of combined crushed stone and construction sand and gravel ever recorded in the U.S. The outlook for construction aggregates and the issues facing the industry are discussed.

  10. Issues in packet radio network design

    NASA Technical Reports Server (NTRS)

    Leiner, Barry M.; Nielson, Donald L.; Tobagi, Fouad A.

    1987-01-01

    The physical aspects of a packet radio network design, the automated management of the network, and the interface of the network to the users are examined. The networks provide data communications to users located over a broad geographic region where direct radio or wire connection between the source and destination user is not practical; the network consists of a radio, antenna, and digital controller. The physical connectivity, bandwidth-time-space management, channel access, and data link control of the network are analyzed. Consideration is given to link determination and control, routing and packet forwarding, congestion and flow control, and supported users management. The operation and management of a packet radio network, in particular network deployment and maintenance, network access methods, and its effect on the radio spectrum, are discussed. The performance and cost of a packet radio network are evaluated.

  11. Individualized Science Packets for Gifted Students.

    ERIC Educational Resources Information Center

    Blurton, Craig

    1983-01-01

    Discusses four problems facing gifted students in elementary science classrooms. Suggests development of teacher-made science packets to resolve these and other problems. A sample lesson on animal classification for grade three is provided. (JN)

  12. Unidirectional transport of wave packets through tilted discrete breathers in nonlinear lattices with asymmetric defects

    NASA Astrophysics Data System (ADS)

    Bai, Xiao-Dong; Malomed, Boris A.; Deng, Fu-Guo

    2016-09-01

    We consider the transfer of lattice wave packets through a tilted discrete breather (TDB) in opposite directions in the discrete nonlinear Schrödinger model with asymmetric defects, which may be realized as a Bose-Einstein condensate trapped in a deep optical lattice, or as optical beams in a waveguide array. A unidirectional transport mode is found, in which the incident wave packets, whose energy belongs to a certain interval between full reflection and full passage regions, pass the TDB only in one direction, while in the absence of the TDB, the same lattice admits bidirectional propagation. The operation of this mode is accurately explained by an analytical consideration of the respective energy barriers. The results suggest that the TDB may emulate the unidirectional propagation of atomic and optical beams in various settings. In the case of the passage of the incident wave packet, the scattering TDB typically shifts by one lattice unit in the direction from which the wave packet arrives, which is an example of the tractor-beam effect, provided by the same system, in addition to the rectification of incident waves.

  13. Comparison of Ring-Buffer-Based Packet Capture Solutions

    SciTech Connect

    Barker, Steven Andrew

    2015-10-01

    Traditional packet-capture solutions using commodity hardware incur a large amount of overhead as packets are copied multiple times by the operating system. This overhead slows sensor systems to a point where they are unable to keep up with high bandwidth traffic, resulting in dropped packets. Incomplete packet capture files hinder network monitoring and incident response efforts. While costly commercial hardware exists to capture high bandwidth traffic, several software-based approaches exist to improve packet capture performance using commodity hardware.

  14. Time of arrival in quantum and Bohmian mechanics

    NASA Astrophysics Data System (ADS)

    Leavens, C. R.

    1998-08-01

    In a recent paper Grot, Rovelli, and Tate (GRT) [Phys. Rev. A 54, 4676 (1996)] derived an expression for the probability distribution π(TX) of intrinsic arrival times T(X) at position x=X for a quantum particle with initial wave function ψ(x,t=0) freely evolving in one dimension. This was done by quantizing the classical expression for the time of arrival of a free particle at X, assuming a particular choice of operator ordering, and then regulating the resulting time of arrival operator. For the special case of a minimum-uncertainty-product wave packet at t=0 with average wave number and variance Δk they showed that their analytical expression for π(TX) agreed with the probability current density J(x=X,t=T) only to terms of order Δk/. They dismissed the probability current density as a viable candidate for the exact arrival time distribution on the grounds that it can sometimes be negative. This fact is not a problem within Bohmian mechanics where the arrival time distribution for a particle, either free or in the presence of a potential, is rigorously given by \\|J(X,T)\\| (suitably normalized) [W. R. McKinnon and C. R. Leavens, Phys. Rev. A 51, 2748 (1995); C. R. Leavens, Phys. Lett. A 178, 27 (1993); M. Daumer et al., in On Three Levels: The Mathematical Physics of Micro-, Meso-, and Macro-Approaches to Physics, edited by M. Fannes et al. (Plenum, New York, 1994); M. Daumer, in Bohmian Mechanics and Quantum Theory: An Appraisal, edited by J. T. Cushing et al. (Kluwer Academic, Dordrecht, 1996)]. The two theories are compared in this paper and a case presented for which the results could not differ more: According to GRT's theory, every particle in the ensemble reaches a point x=X, where ψ(x,t) and J(x,t) are both zero for all t, while no particle ever reaches X according to the theory based on Bohmian mechanics. Some possible implications are discussed.

  15. STS-93: Chandra Crew Arrival

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The primary objective of the STS-93 mission was to deploy the Advanced X-ray Astrophysical Facility, which had been renamed the Chandra X-ray Observatory in honor of the late Indian-American Nobel Laureate Subrahmanyan Chandrasekhar. The mission was launched at 12:31 on July 23, 1999 onboard the space shuttle Columbia. The mission was led by Commander Eileen Collins. The crew was Pilot Jeff Ashby and Mission Specialists Cady Coleman, Steve Hawley and Michel Tognini from the Centre National d'Etudes Spatiales (CNES). This videotape shows the astronauts arrival at Kennedy Space Center a week before the launch. Each of the astronauts gives brief remarks, beginning with Eileen Collins, the first woman to command a space mission.

  16. Dynamics of Attosecond Electron Wave Packets

    NASA Astrophysics Data System (ADS)

    Mauritsson, Johan

    2005-05-01

    We present results from some of the first experimental studies of attosecond electron wave packets created via the absorption of ultrashort extreme ultraviolet (XUV) light pulses [1]. The pulses, made via high harmonic generation, form an attosecond pulse train (APT) whose properties we can manipulate by a combination of spatial and spectral filtering. For instance, we show that on-target attosecond pulses of 170 as duration, which is close to the single cycle limit, can be produced [2]. The electron wave packets created when such an APT is used to ionize an atom are different from the tunneling wave packets familiar from strong field ionization. We show how to measure the dynamics of these wave packets in a strong infrared (IR) field, where the absorption of energy above the ionization threshold is found to depend strongly on the APT-IR delay [3]. We also demonstrate that altering the properties of the initial electron wave packet by manipulating the APT changes the subsequent continuum electron dynamics. Finally, we show how the phase of a longer, femtosecond electron wave packet can be modulated by a moderately strong IR pulse with duration comparable to or shorter than that of the electron wave packet. This experiment reveals how the normal ponderomotive shift of an XUV ionization event is modified when the IR pulse is shorter than the XUV pulse.[1] The experiments were done at Lund Institute of Technology, Sweden.[2] R. López-Martens, et al., Phys. Rev. Lett. 94, 033001 (2005)[3] P. Johnsson, et al., submitted to Phys. Rev. Lett.

  17. Radiology/Imaging. Clinical Rotation. Instructor's Packet and Student Study Packet.

    ERIC Educational Resources Information Center

    Texas Univ., Austin. Extension Instruction and Materials Center.

    The instructor's packet, the first of two packets, is one of a series of materials designed to help students who are investigating the activities within a radiology department or considering any of the imaging technologies as a career. The material is designed to relate training experience to information studied in the classroom. This packet…

  18. Social Security. Cooperative Work Experience Learning Activity Packet: Series on Job Entry and Adjustment; Packet Six.

    ERIC Educational Resources Information Center

    Herschbach, Dennis R.; And Others

    This student booklet is sixth in an illustrated series of eleven learning activity packets for use in teaching job hunting and application procedures and the management of wages to secondary students. Four units are included in this packet to explain (1) the different benefits social security provides and the principles behind the program; (2) the…

  19. Acoustic multipath arrivals in the horizontal plane due to approaching nonlinear internal waves.

    PubMed

    Badiey, Mohsen; Katsnelson, Boris G; Lin, Ying-Tsong; Lynch, James F

    2011-04-01

    Simultaneous measurements of acoustic wave transmissions and a nonlinear internal wave packet approaching an along-shelf acoustic path during the Shallow Water 2006 experiment are reported. The incoming internal wave packet acts as a moving frontal layer reflecting (or refracting) sound in the horizontal plane. Received acoustic signals are filtered into acoustic normal mode arrivals. It is shown that a horizontal multipath interference is produced. This has previously been called a horizontal Lloyd's mirror. The interference between the direct path and the refracted path depends on the mode number and frequency of the acoustic signal. A mechanism for the multipath interference is shown. Preliminary modeling results of this dynamic interaction using vertical modes and horizontal parabolic equation models are in good agreement with the observed data.

  20. All-optical buffering for DPSK packets

    NASA Astrophysics Data System (ADS)

    Liu, Guodong; Wu, Chongqing; Liu, Lanlan; Wang, Fu; Mao, Yaya; Sun, Zhenchao

    2013-12-01

    Advanced modulation formats, such as DPSK, DQPSK, QAM, have become the mainstream technologies in the optical network over 40Gb/s, the DPSK format is the fundamental of all advanced modulation formats. Optical buffers, as a key element for temporarily storing packets in order to synchronization or contention resolution in optical nodes, must be adapted to this new requirement. Different from other current buffers to store the NRZ or RZ format, an all-optical buffer of storing DPSK packets based on nonlinear polarization rotation in SOA is proposed and demonstrated. In this buffer, a section of PMF is used as fiber delay line to maintain the polarization states unchanged, the driver current of SOA is optimized, and no amplifier is required in the fiber loop. A packet delay resolution of 400ns is obtained and storage for tens rounds is demonstrated without significant signal degradation. Using proposed the new tunable DPSK demodulator, bit error rate has been measured after buffering for tens rounds for 10Gb/s data payload. Configurations for First-in First-out (FIFO) buffer or First-in Last-out (FILO) buffer are proposed based on this buffer. The buffer is easy control and suitable for integration. The terminal contention caused by different clients can be mitigated by managing packets delays in future all-optical network, such as optical packet switching network and WDM switching network.

  1. High Angular Momentum Rydberg Wave Packets

    NASA Astrophysics Data System (ADS)

    Wyker, Brendan

    2011-12-01

    High angular momentum Rydberg wave packets are studied. Application of carefully tailored electric fields to low angular momentum, high- n (n ˜ 300) Rydberg atoms creates coherent superpositions of Stark states with near extreme values of angular momentum, ℓ. Wave packet components orbit the parent nucleus at rates that depend on their energy, leading to periods of localization and delocalization as the components come into and go out of phase with each other. Monitoring survival probability signals in the presence of position dependent probing leads to observation of characteristic oscillations based on the composition of the wave packet. The discrete nature of electron energy levels is observed through the measurement of quantum revivals in the wave packet localization signal. Time-domain spectroscopy of these signals allows determination of both the population and phase of individual superposition components. Precise manipulation of wave packets is achieved through further application of pulsed electric fields. Decoherence effects due to background gas collisions and electrical noise are also detailed. Quantized classical trajectory Monte-Carlo simulations are introduced and agree remarkably well with experimental results.

  2. Packet radar spectrum recovery for physiological signals.

    PubMed

    Yavari, Ehsan; Padasdao, Bryson; Lubecke, Victor; Boric-Lubecke, Olga

    2013-01-01

    Packet Doppler radar is investigated for extracting physiological signals. System on Chip is employed as a signal source in packet mode, and it transmits signals intermittently at 2.405 GHz to save power. Reflected signals are demodulated directly by spectral analysis of received pulses in the baseband. Spectral subtraction, using data from an empty room, is applied to extract the periodic movement. It was experimentally demonstrated that frequency of the periodic motion can be accurately extracted using this technique. Proposed approach reduces the computation complexity of the signal processing part effectively. PMID:24110048

  3. Packet radar spectrum recovery for physiological signals.

    PubMed

    Yavari, Ehsan; Padasdao, Bryson; Lubecke, Victor; Boric-Lubecke, Olga

    2013-01-01

    Packet Doppler radar is investigated for extracting physiological signals. System on Chip is employed as a signal source in packet mode, and it transmits signals intermittently at 2.405 GHz to save power. Reflected signals are demodulated directly by spectral analysis of received pulses in the baseband. Spectral subtraction, using data from an empty room, is applied to extract the periodic movement. It was experimentally demonstrated that frequency of the periodic motion can be accurately extracted using this technique. Proposed approach reduces the computation complexity of the signal processing part effectively.

  4. NASA Dual Precipitation Radar Arrives at Goddard

    NASA Video Gallery

    The Dual-frequency Precipitation Radar (DPR) built by the Japan Aerospace Exploration Agency (JAXA) for the Global Precipitation Measurement (GPM) mission's Core Observatory arrived on Friday, Marc...

  5. Construction aggregates

    USGS Publications Warehouse

    Nelson, T.I.; Bolen, W.P.

    2007-01-01

    Construction aggregates, primarily stone, sand and gravel, are recovered from widespread naturally occurring mineral deposits and processed for use primarily in the construction industry. They are mined, crushed, sorted by size and sold loose or combined with portland cement or asphaltic cement to make concrete products to build roads, houses, buildings, and other structures. Much smaller quantities are used in agriculture, cement manufacture, chemical and metallurgical processes, glass production and many other products.

  6. Construction aggregates

    USGS Publications Warehouse

    Tepordei, V.V.

    1996-01-01

    Part of the Annual Commodities Review 1995. Production of construction aggregates such as crushed stone and construction sand and gravel showed a marginal increase in 1995. Most of the 1995 increases were due to funding for highway construction work. The major areas of concern to the industry included issues relating to wetlands classification and the classification of crystalline silica as a probable human carcinogen. Despite this, an increase in demand is anticipated for 1996.

  7. Construction aggregates

    USGS Publications Warehouse

    Tepordei, V.V.

    1993-01-01

    Part of a special section on the market performance of industrial minerals in 1992. Production of construction aggregates increased by 4.6 percent in 1992. This increase was due, in part, to the increased funding for transportation and infrastructure projects. The U.S. produced about 1.05 Gt of crushed stone and an estimated 734 Mt of construction sand and gravel in 1992. Demand is expected to increase by about 5 percent in 1993.

  8. All-optical packet header and payload separation for un-slotted optical packet switched networks

    NASA Astrophysics Data System (ADS)

    Ji, Wei; Zhang, Min; Ye, Peida

    2005-11-01

    A novel all-optical header and payload separation technique that can be utilized in un-slotted optical packet switched networks is presented. The technique uses a modified TOAD for packet header extraction with differential modulation scheme and two SOAs that perform a simple XOR operation between the packet and its self-derived header to get the separated payload. The main virtue of this system is simple structure and need not any additional continuous pulses. Through numerical simulations, the operating characteristics of the scheme are illustrated. In addition, the parameters of the system are discussed and designed to optimize the operation performance.

  9. Time-of-Flight Measurements of Single-Electron Wave Packets in Quantum Hall Edge States

    NASA Astrophysics Data System (ADS)

    Kataoka, M.; Johnson, N.; Emary, C.; See, P.; Griffiths, J. P.; Jones, G. A. C.; Farrer, I.; Ritchie, D. A.; Pepper, M.; Janssen, T. J. B. M.

    2016-03-01

    We report time-of-flight measurements on electrons traveling in quantum Hall edge states. Hot-electron wave packets are emitted one per cycle into edge states formed along a depleted sample boundary. The electron arrival time is detected by driving a detector barrier with a square wave that acts as a shutter. By adding an extra path using a deflection barrier, we measure a delay in the arrival time, from which the edge-state velocity v is deduced. We find that v follows 1 /B dependence, in good agreement with the E →×B → drift. The edge potential is estimated from the energy dependence of v using a harmonic approximation.

  10. Controllably accelerating and decelerating Airy–Bessel–Gaussian wave packets

    NASA Astrophysics Data System (ADS)

    Deng, Fu; Yu, Weihao; Deng, Dongmei

    2016-11-01

    By solving the (3  +  1)D free-space Schrödinger equation in polar coordinates analytically, we have investigated the propagation of 3D controllably accelerating and decelerating Airy–Bessel–Gaussian (CAiBG) wave packets, even CAiBG wave packets, odd CAiBG wave packets and the superposition of several CAiBG wave packets in free space. The CAiBG wave packets are constructed with the Airy pulses with initial velocity in temporal domain and the Bessel–Gaussian beams in space domain. Due to the initial velocity on Airy pulses, we can obtain decelerating and accelerating Airy–Bessel–Gaussian wave packets by selecting different initial velocities. Moreover, by superposing several CAiBG wave packets, we can obtain the rotating wave packets.

  11. The European Space Agency standard for space packet utilisation

    NASA Technical Reports Server (NTRS)

    Kaufeler, J.-F.; Parkes, A.; Pidgeon, A.

    1993-01-01

    This paper presents the ESA concept for the use of CCSDS defined Telemetry and Telecommand Packets at the application level. These Packets are used to monitor and control remotely a space born application. This concept is defined in a Packet Utilisation Standard (PUS) which should become applicable for all ESA missions using Packets. The production of this standard is under the responsibility of an ESA standardization group called 'COES'.

  12. Solid Waste Activity Packet for Teachers.

    ERIC Educational Resources Information Center

    Illinois Univ., Urbana. Cooperative Extension Service.

    This solid waste activity packet introduces students to the solid waste problem in Illinois. Topics explore consumer practices in the market place, packaging, individual and community garbage generation, and disposal practices. The activities provide an integrated approach to incorporating solid waste management issues into subject areas. The…

  13. The Air We Breathe. Activity Packet.

    ERIC Educational Resources Information Center

    Connecticut State Dept. of Environmental Protection, Hartford.

    This packet of materials is intended to provide teachers with an interdisciplinary approach to integrating air quality education into the existing curriculum of Connecticut schools. The unit is designed to complement the student booklet "The Air We Breathe," which is included. A major portion of the document is comprised of teaching activities.…

  14. Biological Diversity. Global Issues Education Packet.

    ERIC Educational Resources Information Center

    Holm, Amy E.

    Biological diversity, also commonly called genetic diversity, refers to the variety of organisms on Earth. Scientists are concerned that many species will become extinct because of extensive development in the tropical regions. This packet is designed to increase student's awareness about direct and indirect causes of extinction, endangered…

  15. Peninsula Humane Society Teacher's Packet. Secondary Level.

    ERIC Educational Resources Information Center

    Peninsula Humane Society, San Mateo, CA.

    Activities in this teacher's packet are designed to familiarize secondary school students with the responsibilities involved in pet ownership. Teaching plans are provided for a total of 12 lessons grouped under social studies, language arts, math, and health sciences. Activities focus on pet overpopulation, expressions of social responses in…

  16. Cashier/Checker Learning Activity Packets (LAPs).

    ERIC Educational Resources Information Center

    Oklahoma State Dept. of Vocational and Technical Education, Stillwater. Curriculum and Instructional Materials Center.

    Twenty-four learning activity packets (LAPs) are provided for six areas of instruction in a cashier/checker program. Section A, Orientation, contains an LAP on exploring the job of cashier-checker. Section B, Operations, has nine LAPs, including those on operating the cash register, issuing trading stamps, and completing the cash register balance…

  17. Metro College for Living. Workshop Packet.

    ERIC Educational Resources Information Center

    Kreps, Alice Roelofs

    This packet contains information and materials for conducting a training workshop for working with adults who are developmentally disabled. The materials are specifically designed to train volunteer teachers in the College for Living (CFL) program, which supplements residential programs in and around Denver and aids institutions in orienting…

  18. Resource Packet on Disability, Spirituality, and Healing.

    ERIC Educational Resources Information Center

    Lane, Nancy

    This resource packet includes information relating to the inclusion of people with disabilities in the Christian church. The first article, "Changing Attitudes, Creating Awareness," highlights several critical areas where churches can begin to understand the barriers of exclusion to people with disabilities. The following article, "Victim…

  19. The World Around You. Environmental Education Packet.

    ERIC Educational Resources Information Center

    Garden Club of America, New York, NY.

    The Garden Club of America has compiled this environmental education packet of informational materials to help teachers educate their students for survival. The "Study Guide" contains essays by ten authorities on topics of population, soil, air, water, power and energy, solid waste management, open space, public lands, oceans, and wildlife. Each…

  20. Passive analysis technique for packet link performance

    NASA Astrophysics Data System (ADS)

    Fairhurst, G.; Wan, P. S.

    1993-01-01

    The performance of a bearer link is usually assessed by bit error rate (BER) tests or measurement of the error free seconds (EFS). These require exclusive access to the link. An alternative technique is presented that measures performance by passive observation of the frames passing over a packet link. This may be used to estimate the performance of the link.

  1. [Alum Rock Voucher Project. Information Packet.

    ERIC Educational Resources Information Center

    Alum Rock Union Elementary School District, San Jose, CA.

    This packet contains (1) informational booklets for parents in the Alum Rock Union Elementary School District, (2) a booklet on the pros and cons of a voucher system, (3) promotional material, (4) a progress report on the project, (5) the project proposal to OEO, and (6) a sample school and program preferences form. The program, according to the…

  2. 8 CFR 232.3 - Arriving aliens.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 8 Aliens and Nationality 1 2013-01-01 2013-01-01 false Arriving aliens. 232.3 Section 232.3 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS DETENTION OF ALIENS FOR PHYSICAL AND MENTAL EXAMINATION § 232.3 Arriving aliens. When a district director has reasonable...

  3. 8 CFR 232.3 - Arriving aliens.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 8 Aliens and Nationality 1 2014-01-01 2014-01-01 false Arriving aliens. 232.3 Section 232.3 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS DETENTION OF ALIENS FOR PHYSICAL AND MENTAL EXAMINATION § 232.3 Arriving aliens. When a district director has reasonable...

  4. 8 CFR 232.3 - Arriving aliens.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 8 Aliens and Nationality 1 2012-01-01 2012-01-01 false Arriving aliens. 232.3 Section 232.3 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS DETENTION OF ALIENS FOR PHYSICAL AND MENTAL EXAMINATION § 232.3 Arriving aliens. When a district director has reasonable...

  5. 8 CFR 232.3 - Arriving aliens.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 8 Aliens and Nationality 1 2010-01-01 2010-01-01 false Arriving aliens. 232.3 Section 232.3 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS DETENTION OF ALIENS FOR PHYSICAL AND MENTAL EXAMINATION § 232.3 Arriving aliens. When a district director has reasonable...

  6. 8 CFR 232.3 - Arriving aliens.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 8 Aliens and Nationality 1 2011-01-01 2011-01-01 false Arriving aliens. 232.3 Section 232.3 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS DETENTION OF ALIENS FOR PHYSICAL AND MENTAL EXAMINATION § 232.3 Arriving aliens. When a district director has reasonable...

  7. PROJECT SUCCESS: Art. (Introductory Packet, Drawing, Claywork, Painting).

    ERIC Educational Resources Information Center

    Petersen, Nancy

    Four packets comprise the art component of an enrichment program for gifted elementary students. The introduction packet reviews identification of children gifted in art through pre and post measures. A drawing packet reviews techniques for such activities as human figure drawing, shading, crayon rubbinqs, experimenting with perspective, and…

  8. STS-114: Discovery Crew Arrival

    NASA Technical Reports Server (NTRS)

    2005-01-01

    George Diller of NASA Public Affairs narrates the STS-114 Crew arrival at Kennedy Space Center aboard a Gulf Stream aircraft. They were greeted by Center Director Jim Kennedy. Commander Eileen Collins introduced each of her crew members and gave a brief description of their roles in the mission. Mission Specialist 3, Andrew Thomas will be the lead crew member on the inspection on flight day 2; he is the intravehicular (IV) crew member that will help and guide Mission Specialists Souichi Noguchi and Stephen Robinson during their spacewalks. Pilot James Kelly will be operating the shuttle systems in flying the Shuttle; he will be flying the space station robotic arm during the second extravehicular activity and he will be assisting Mission Specialist Wendy Lawrence during the other two extravehicular activities; he will be assisting on the rendezvous on flight day three, and landing of the shuttle. Commander Collins also mentioned Pilot Kelly's recent promotion to Colonel by the United States Air Force. Mission Specialist 1, Souichi Noguchi from JAXA (The Japanese Space Agency) will be flying on the flight deck for ascent; he will be doing three spacewalks on day 5, 7, and 9; He will be the photo/TV lead for the different types of cameras on board to document the flight and to send back the information to the ground for both technical and public affairs reasons. Mission Specialist 5, Charles Camada will be doing the inspection on flight day 2 with Mission Specialist Thomas and Pilot Kelly; he will be transferring the logistics off the shuttle and onto the space station and from the space station back to the shuttle; He will help set up eleven lap tops on board. Mission Specialist 4, Wendy Lawrence will lead the transfer of logistics to the space station; she is the space station arm operator during extravehicular activities 1 and 3; she will be carrying the 6,000 pounds of external storage platform from the shuttle payload bay over to the space station; she is also

  9. Construction aggregates

    USGS Publications Warehouse

    Bolen, W.P.; Tepordei, V.V.

    2001-01-01

    The estimated production during 2000 of construction aggregates, crushed stone, and construction sand and gravel increased by about 2.6% to 2.7 Gt (3 billion st), compared with 1999. The expansion that started in 1992 continued with record production levels for the ninth consecutive year. By commodity, construction sand and gravel production increased by 4.5% to 1.16 Gt (1.28 billion st), while crushed stone production increased by 1.3% to 1.56 Gt (1.72 billion st).

  10. Effects of inter-packet spacing on the delivery of multimedia content

    SciTech Connect

    Kapadia, A. C.; Feng, A. C.; Feng, W. C.

    2001-01-01

    Streaming multimedia content with UDP has become increasingly popular over distributed systems such as the Internet. However, because UDP does not possess any congestion-control mechanism and most best-effort trafic is served by the congestion-controlled TCP, UDP flows steal bandwidth from TCP to the point that TCP flows can starve for network resources. Furthermore, such applications may cause the Internet infrastructure to eventually suffer from congestion collapse because UDP trafic does not self-regulate itself. To address this problem, next-generation Internet routers will implement active queue-management schemes to punish malicious traffic, e.g., non-adaptive UDP flows, and to the improve the performance of congestion-controlled traffic, e.g., TCP flows. The arrival of such routers will cripple the performance of today's UDP-based multimedia applications. So, in this paper, we introduce the notion of inter-packet spacing with control feedback to enable these UDP-based applications to perform well in the next-generation Internet while being adaptive and self-regulating. When compared with traditional UDP-based multimedia streaming, we illustrate that our counterintuitive, interpacket-spacing scheme with control feedback can reduce packet loss by 90% without adversely affecting delivered throughput. Keywords: network protocol, multimedia, packet spacing, rate-adjusting congestion control.

  11. Architectures and Design for Next-Generation Hybrid Circuit/Packet Networks

    NASA Astrophysics Data System (ADS)

    Vadrevu, Sree Krishna Chaitanya

    Internet traffic is increasing rapidly at an annual growth rate of 35% with aggregate traffic exceeding several Exabyte's per month. The traffic is also becoming heterogeneous in bandwidth and quality-of-service (QoS) requirements with growing popularity of cloud computing, video-on-demand (VoD), e-science, etc. Hybrid circuit/packet networks which can jointly support circuit and packet services along with the adoption of high-bit-rate transmission systems form an attractive solution to address the traffic growth. 10 Gbps and 40 Gbps transmission systems are widely deployed in telecom backbone networks such as Comcast, AT&T, etc., and network operators are considering migration to 100 Gbps and beyond. This dissertation proposes robust architectures, capacity migration strategies, and novel service frameworks for next-generation hybrid circuit/packet architectures. In this dissertation, we study two types of hybrid circuit/packet networks: a) IP-over-WDM networks, in which the packet (IP) network is overlaid on top of the circuit (optical WDM) network and b) Hybrid networks in which the circuit and packet networks are deployed side by side such as US DoE's ESnet. We investigate techniques to dynamically migrate capacity between the circuit and packet sections by exploiting traffic variations over a day, and our methods show that significant bandwidth savings can be obtained with improved reliability of services. Specifically, we investigate how idle backup circuit capacity can be used to support packet services in IP-over-WDM networks, and similarly, excess capacity in packet network to support circuit services in ESnet. Control schemes that enable our mechanisms are also discussed. In IP-over-WDM networks, with upcoming 100 Gbps and beyond, dedicated protection will induce significant under-utilization of backup resources. We investigate design strategies to loan idle circuit backup capacity to support IP/packet services. However, failure of backup circuits will

  12. X-36 arrival at Dryden

    NASA Technical Reports Server (NTRS)

    1996-01-01

    NASA and McDonnell Douglas Corporation (MDC) personnel steady the X-36 Tailless Fighter Agility Research Aircraft following arrival at NASA Dryden Flight Research Center, Edwards, California, on July 2, 1996. The aircraft is being hoisted out of it's shipping crate. The NASA/Boeing X-36 Tailless Fighter Agility Research Aircraft program successfully demonstrated the tailless fighter design using advanced technologies to improve the maneuverability and survivability of possible future fighter aircraft. The program met or exceeded all project goals. For 31 flights during 1997 at the Dryden Flight Research Center, Edwards, California, the project team examined the aircraft's agility at low speed / high angles of attack and at high speed / low angles of attack. The aircraft's speed envelope reached up to 206 knots (234 mph). This aircraft was very stable and maneuverable. It handled very well. The X-36 vehicle was designed to fly without the traditional tail surfaces common on most aircraft. Instead, a canard forward of the wing was used as well as split ailerons and an advanced thrust-vectoring nozzle for directional control. The X-36 was unstable in both pitch and yaw axes, so an advanced, single-channel digital fly-by-wire control system (developed with some commercially available components) was put in place to stabilize the aircraft. Using a video camera mounted in the nose of the aircraft and an onboard microphone, the X-36 was remotely controlled by a pilot in a ground station virtual cockpit. A standard fighter-type head-up display (HUD) and a moving-map representation of the vehicle's position within the range in which it flew provided excellent situational awareness for the pilot. This pilot-in-the-loop approach eliminated the need for expensive and complex autonomous flight control systems and the risks associated with their inability to deal with unknown or unforeseen phenomena in flight. Fully fueled the X-36 prototype weighed approximately 1,250 pounds

  13. Effect of Coulomb interaction on multi-electronwave packet dynamics

    SciTech Connect

    Shiokawa, T.; Takada, Y.; Konabe, S.; Hatsugai, Y.; Muraguchi, M.; Endoh, T.; Shiraishi, K.

    2013-12-04

    We have investigated the effect of Coulomb interaction on electron transport in a one-dimensional nanoscale structure using a multi-electron wave packet approach. To study the time evolution, we numerically solve the time-dependent Hartree-Fock equation, finding that the electron wave packet dynamics strongly depends on the Coulomb interaction strength. When the Coulomb interaction is large, each electron wave packet moves separately in the presence of an electric field. With weak Coulomb interaction, however, the electron wave packets overlap, forming and moving as one collective wave packet.

  14. Spin Models for Packet Routing Control in Computer Networks

    NASA Astrophysics Data System (ADS)

    Horiguchi, T.

    We investigate packet flow in computer networks within the framework of statistical physics by using numerical simulations. As mathematical models for packet routing, we present a spin model with lattice gas spins and the one with Ising spins. Then we propose dynamic programming for optimal routing control of packet flow by using the two spin models. This is a kind of goal-directed learning for taking into account of time-dependent environment for the packets. Next we investigate a congestion problem by using the model with lattice gas spins when the packets are not sent to nodes at which their buffers are already full up with packets. Since we have found serious congestion in the packet flow, we then propose reinforcement learning for avoiding the congestion and have performed simulations on several networks including small world networks, scale free networks and so on.

  15. Wavelet packet entropy for heart murmurs classification.

    PubMed

    Safara, Fatemeh; Doraisamy, Shyamala; Azman, Azreen; Jantan, Azrul; Ranga, Sri

    2012-01-01

    Heart murmurs are the first signs of cardiac valve disorders. Several studies have been conducted in recent years to automatically differentiate normal heart sounds, from heart sounds with murmurs using various types of audio features. Entropy was successfully used as a feature to distinguish different heart sounds. In this paper, new entropy was introduced to analyze heart sounds and the feasibility of using this entropy in classification of five types of heart sounds and murmurs was shown. The entropy was previously introduced to analyze mammograms. Four common murmurs were considered including aortic regurgitation, mitral regurgitation, aortic stenosis, and mitral stenosis. Wavelet packet transform was employed for heart sound analysis, and the entropy was calculated for deriving feature vectors. Five types of classification were performed to evaluate the discriminatory power of the generated features. The best results were achieved by BayesNet with 96.94% accuracy. The promising results substantiate the effectiveness of the proposed wavelet packet entropy for heart sounds classification.

  16. A packet switched communications system for GRO

    NASA Astrophysics Data System (ADS)

    Husain, Shabu; Yang, Wen-Hsing; Vadlamudi, Rani; Valenti, Joseph

    1993-11-01

    This paper describes the packet switched Instrumenters Communication System (ICS) that was developed for the Command Management Facility at GSFC to support the Gamma Ray Observatory (GRO) spacecraft. The GRO ICS serves as a vital science data acquisition link to the GRO scientists to initiate commands for their spacecraft instruments. The system is ready to send and receive messages at any time, 24 hours a day and seven days a week. The system is based on X.25 and the International Standard Organization's (ISO) 7-layer Open Systems Interconnection (OSI) protocol model and has client and server components. The components of the GRO ICS are discussed along with how the Communications Subsystem for Interconnection (CSFI) and Network Control Program Packet Switching Interface (NPSI) software are used in the system.

  17. Steering attosecond electron wave packets with light.

    PubMed

    Kienberger, R; Hentschel, M; Uiberacker, M; Spielmann, Ch; Kitzler, M; Scrinzi, A; Wieland, M; Westerwalbesloh, Th; Kleineberg, U; Heinzmann, U; Drescher, M; Krausz, F

    2002-08-16

    Photoelectrons excited by extreme ultraviolet or x-ray photons in the presence of a strong laser field generally suffer a spread of their energies due to the absorption and emission of laser photons. We demonstrate that if the emitted electron wave packet is temporally confined to a small fraction of the oscillation period of the interacting light wave, its energy spectrum can be up- or downshifted by many times the laser photon energy without substantial broadening. The light wave can accelerate or decelerate the electron's drift velocity, i.e., steer the electron wave packet like a classical particle. This capability strictly relies on a sub-femtosecond duration of the ionizing x-ray pulse and on its timing to the phase of the light wave with a similar accuracy, offering a simple and potentially single-shot diagnostic tool for attosecond pump-probe spectroscopy.

  18. Particlelike wave packets in complex scattering systems

    NASA Astrophysics Data System (ADS)

    Gérardin, Benoît; Laurent, Jérôme; Ambichl, Philipp; Prada, Claire; Rotter, Stefan; Aubry, Alexandre

    2016-07-01

    A wave packet undergoes a strong spatial and temporal dispersion while propagating through a complex medium. This wave scattering is often seen as a nightmare in wave physics whether it be for focusing, imaging, or communication purposes. Controlling wave propagation through complex systems is thus of fundamental interest in many areas, ranging from optics or acoustics to medical imaging or telecommunications. Here, we study the propagation of elastic waves in a cavity and a disordered waveguide by means of laser interferometry. From the direct experimental access to the time-delay matrix of these systems, we demonstrate the existence of particlelike wave packets that remain focused in time and space throughout their complex trajectory. Due to their limited dispersion, their selective excitation will be crucially relevant for all applications involving selective wave focusing and efficient information transfer through complex media.

  19. Teleportation of nonclassical wave packets of light.

    PubMed

    Lee, Noriyuki; Benichi, Hugo; Takeno, Yuishi; Takeda, Shuntaro; Webb, James; Huntington, Elanor; Furusawa, Akira

    2011-04-15

    We report on the experimental quantum teleportation of strongly nonclassical wave packets of light. To perform this full quantum operation while preserving and retrieving the fragile nonclassicality of the input state, we have developed a broadband, zero-dispersion teleportation apparatus that works in conjunction with time-resolved state preparation equipment. Our approach brings within experimental reach a whole new set of hybrid protocols involving discrete- and continuous-variable techniques in quantum information processing for optical sciences.

  20. New Expedition 32 Trio Arrives at Station

    NASA Video Gallery

    Expedition 32 Flight Engineers Suni Williams, Yuri Malenchenko and Aki Hoshide have arrived at the International Space Station after two days in orbit. The new trio docked its Soyuz TMA-05M spacecr...

  1. New Crew Members Arrive at Station

    NASA Video Gallery

    The Expedition 28 crew expanded to six members with the arrival of Flight Engineers Mike Fossum, Sergei Volkov and Satoshi Furukawa. The new trio docked to the International Space Station in the So...

  2. Packet theory of conditioning and timing.

    PubMed

    Kirkpatrick, Kimberly

    2002-04-28

    Packet theory is based on the assumption that the momentary probability of producing a bout or packet of responding is controlled by the conditional expected time function. Bouts of head entry responses of rats into a food cup appear to have the same characteristics across a range of conditions. The conditional expected time function is the mean expected time remaining until the next food delivery as a function of time since an event such as food or stimulus onset. The conditional expected time function encodes mean interval duration as well as the distribution form so that both the mean response rate and form of responding in time can be predicted. Simulations of Packet theory produced accurate quantitative predictions of: (1) the effect of reinforcement density (mean food-food interval) and distribution form on responding; (2) scalar variance in fixed interval responding; (3) CS-US and intertrial interval effects on the strength of conditioning; and (4) the effect of the ratio of cycle:trial time on the strength of conditioning.

  3. BAG (Continuous Round Robin Packet Capture)

    SciTech Connect

    Wood, C. Philip

    2006-03-10

    Bag is a miniature pcap filter which takes pcap input (or input off the wire) using a bpf filter, if specified, and then writes the output to stdout or a file (in pcap format). It depends for some aspects of its functionality on a libpcap library which uses a shared memory packet capture ring bugger. There are two build in modules: chcksum and session. the build in chcksum modules is used to anonymize the ip addresses and repair any checksums in the stream. % bag -r /tmp/*.pcap -Cchucksum, 128.1 65: 10.10 The session module generates sessions which are defined as a series of packets that have two things in common. the first is a unique five-tuple composed oi an IP protocol, IP source address, IP source port, IP destination address, and IP destination port. The second is that if the originating packet is associated with a bi-directional service such as ftpltcp, characteristics and data will be kept for both flows involved with the service. The only protocols evaluated beyond the IP header are ICMP, TCP and UDP. A session can last for as long as bag is running. However, under normal conditions, sessions are generated every time they appear to have closed down. There is a man page included with the distribution which goes into more detail.

  4. BAG (Continuous Round Robin Packet Capture)

    2006-03-10

    Bag is a miniature pcap filter which takes pcap input (or input off the wire) using a bpf filter, if specified, and then writes the output to stdout or a file (in pcap format). It depends for some aspects of its functionality on a libpcap library which uses a shared memory packet capture ring bugger. There are two build in modules: chcksum and session. the build in chcksum modules is used to anonymize the ipmore » addresses and repair any checksums in the stream. % bag -r /tmp/*.pcap -Cchucksum, 128.1 65: 10.10 The session module generates sessions which are defined as a series of packets that have two things in common. the first is a unique five-tuple composed oi an IP protocol, IP source address, IP source port, IP destination address, and IP destination port. The second is that if the originating packet is associated with a bi-directional service such as ftpltcp, characteristics and data will be kept for both flows involved with the service. The only protocols evaluated beyond the IP header are ICMP, TCP and UDP. A session can last for as long as bag is running. However, under normal conditions, sessions are generated every time they appear to have closed down. There is a man page included with the distribution which goes into more detail.« less

  5. Resilient packet ring media access protocol

    NASA Astrophysics Data System (ADS)

    Thepot, Frederic

    2001-07-01

    The discussion will cover the new initiative to create a new MAC layer standard for resilient packet rings: IEEE 802.17 RPR. The key aspects of the presentation will include a preliminary address of the Metro Area Network today and the current networking technologies such as SONET/SDH which are not optimized to carry IP traffic over Metro MAN. The next segment will cover the options which could change the traditional and expensive layered networking model, and address the real benefits of marrying several technologies like Ethernet, SONET/SDH and IP into one technology. The next part of the discussion will detail the technical advantages a new MAC will bring to the services providers. Lastly a summary of the view and strategy about the acceptance and deployment of this new technology in the next 12 months, specifically, now one defines and develops standards for a Resilient Packet Ring Access Protocol for use in Local, Metropolitan, and Wide Area Networks for transfer of data packets at rates scalable to multiple gigabits per second; specifically address the data transmission requirements of carriers that have present and planned fiber optic physical infrastructure in a ring topology; and, defining and developing detailed specifications for using existing and/or new physical layers at appropriate data rates that will support transmission of this access protocol.

  6. Pair bonds: arrival synchrony in migratory birds.

    PubMed

    Gunnarsson, T G; Gill, J A; Sigurbjörnsson, T; Sutherland, W J

    2004-10-01

    Synchronous arrival of pairs of migratory birds at their breeding grounds is important for maintaining pair bonds and is achieved by pairs that remain together all year round. Here we show that arrival is also synchronized in paired individuals of a migratory shorebird, the black-tailed godwit (Limosa limosa islandica), even though they winter hundreds of kilometres apart and do not migrate together. The mechanisms required to achieve this synchrony and prevent 'divorce' illustrate the complexity of migratory systems. PMID:15470417

  7. Quantum arrival time for open systems

    SciTech Connect

    Yearsley, J. M.

    2010-07-15

    We extend previous work on the arrival time problem in quantum mechanics, in the framework of decoherent histories, to the case of a particle coupled to an environment. The usual arrival time probabilities are related to the probability current, so we explore the properties of the current for general open systems that can be written in terms of a master equation of the Lindblad form. We specialize to the case of quantum Brownian motion, and show that after a time of order the localization time of the current becomes positive. We show that the arrival time probabilities can then be written in terms of a positive operator-valued measure (POVM), which we compute. We perform a decoherent histories analysis including the effects of the environment and show that time-of-arrival probabilities are decoherent for a generic state after a time much greater than the localization time, but that there is a fundamental limitation on the accuracy {delta}t, with which they can be specified which obeys E{delta}t>>({h_bar}/2{pi}). We confirm that the arrival time probabilities computed in this way agree with those computed via the current, provided there is decoherence. We thus find that the decoherent histories formulation of quantum mechanics provides a consistent explanation for the emergence of the probability current as the classical arrival time distribution, and a systematic rule for deciding when probabilities may be assigned.

  8. 19 CFR 122.31 - Notice of arrival.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... advance notice of arrival in accordance with § 122.22 of this part. (ii) Aircraft arriving from Cuba. Aircraft arriving from Cuba must follow the advance notice of arrival procedures set forth in § 122.154 in... aircraft arriving from areas south of the United States (other than Cuba) must follow the advance notice...

  9. Alternative packet switch architectures for a 30/20 GHz FDMA/TDMA geostationary communication satellite network

    NASA Technical Reports Server (NTRS)

    Stehle, Roy; Ogier, Richard G.

    1995-01-01

    This study has investigated alternatives for realizing a packet-based network switch for deployment on a communication satellite. The emphasis was on the avoidance of contention problems that can occur due to the simultaneous arrival of an excessive number of packets destined for the same downlink dwell. The study was to look ahead, beyond the current Advanced Communications Technology Satellite (ACTS) capability, to the next generation of satellites. The study has not been limited by currently available technology, but has used university and commercial research efforts as a basis for designs that can be readily constructed and launched within the next five years. Tradeoffs in memory requirement, power requirement, and architecture have been considered as a part of our study.

  10. Microwave Ionization of an Atomic Electron Wave Packet

    SciTech Connect

    Noel, Michael W.; Ko, Lung; Gallagher, T. F.

    2001-07-23

    A short microwave pulse is used to ionize a lithium Rydberg wave packet launched from the core at a well-defined phase of the field. We observe a strong dependence on the relative phase between the motion of the wave packet and the oscillations of the field. This phase dependent ionization is also studied as a function of the relative frequency. Our experimental observations are in good qualitative agreement with a one-dimensional classical model of wave packet ionization.

  11. Development of optical packet and circuit integrated ring network testbed.

    PubMed

    Furukawa, Hideaki; Harai, Hiroaki; Miyazawa, Takaya; Shinada, Satoshi; Kawasaki, Wataru; Wada, Naoya

    2011-12-12

    We developed novel integrated optical packet and circuit switch-node equipment. Compared with our previous equipment, a polarization-independent 4 × 4 semiconductor optical amplifier switch subsystem, gain-controlled optical amplifiers, and one 100 Gbps optical packet transponder and seven 10 Gbps optical path transponders with 10 Gigabit Ethernet (10GbE) client-interfaces were newly installed in the present system. The switch and amplifiers can provide more stable operation without equipment adjustments for the frequent polarization-rotations and dynamic packet-rate changes of optical packets. We constructed an optical packet and circuit integrated ring network testbed consisting of two switch nodes for accelerating network development, and we demonstrated 66 km fiber transmission and switching operation of multiplexed 14-wavelength 10 Gbps optical paths and 100 Gbps optical packets encapsulating 10GbE frames. Error-free (frame error rate < 1×10(-4)) operation was achieved with optical packets of various packet lengths and packet rates, and stable operation of the network testbed was confirmed. In addition, 4K uncompressed video streaming over OPS links was successfully demonstrated.

  12. Controlling plasmonic wave packets in silver nanowires.

    SciTech Connect

    Cao, L.; Nome, R.; Montgomery, J. M.; Gray, S. K.; Scherer, N. F.

    2010-09-01

    Three-dimensional finite-difference time-domain simulations were performed to explore the excitation of surface plasmon resonances in long silver (Ag) nanowires. In particular, we show that it is possible to generate plasmonic wave packets that can propagate along the nanowire by exciting superpositions of surface plasmon resonances. By using an appropriately chirped pulse, it is possible to transiently achieve localization of the excitation at the distal end of the nanowire. Such designed coherent superpositions will allow realizing spatiotemporal control of plasmonic excitations for enhancing nonlinear responses in plasmonic 'circuits'.

  13. Comparison of all optical forwarding packet architectures

    NASA Astrophysics Data System (ADS)

    Farhat, Rim; Farhat, Amel; Menif, Mourad

    2016-04-01

    In this paper two all optical packet forwarding architectures based on non linear effect in semiconductor optical amplifier in Mach-Zehnder configuration SOA-MZI are studied. The first architecture consist in combing flip flop functionality with the AND logic functionality in the same unit. Error free operation at 40 Gbps for two cascaded nodes is achieved. In the second architecture two separated units namely the flip flop and the AND logic gate are used. 100 Gbps bit rate is reached. At 40 Gbps error free operation is achieved for three cascaded nodes.

  14. Audio-Visual/Communications Teaching Aids Packet. Supplementary Materials. Packet P-8.

    ERIC Educational Resources Information Center

    Peace Corps, Washington, DC. Information Collection and Exchange Div.

    This packet contains three handouts on training theory and the use of audiovisual aids, as well as a section on materials and presentation techniques for use by community development workers concerned with exchanging information and working with the people in a community. The first handout, "Communication in Development," briefly discusses the…

  15. Feedlot Processing and Arrival Cattle Management.

    PubMed

    Noffsinger, Tom; Lukasiewicz, Kip; Hyder, LeeAnn

    2015-11-01

    Acclimating newly arrived cattle in a feedlot setting can increase cattle confidence, reduce stress, improve immune function, and increase cattle well-being. Understanding cattle instincts and using low-stress handling techniques teaches cattle to trust their caregivers and work efficiently for them throughout the feeding period. These techniques should be applied with newly arrived cattle when they are unloaded, moved from the holding pen to the home pen, and handled inside the home pen. Low-stress handling during processing and a sound processing protocol based on cattle history and proper risk assessment can improve cattle health from the start of the feeding period.

  16. Time-dependent wave packet averaged vibrational frequencies from femtosecond stimulated Raman spectra

    NASA Astrophysics Data System (ADS)

    Wu, Yue-Chao; Zhao, Bin; Lee, Soo-Y.

    2016-02-01

    Femtosecond stimulated Raman spectroscopy (FSRS) on the Stokes side arises from a third order polarization, P(3)(t), which is given by an overlap of a first order wave packet, |" separators=" Ψ2 ( 1 ) ( p u , t ) > , prepared by a narrow band (ps) Raman pump pulse, Epu(t), on the upper electronic e2 potential energy surface (PES), with a second order wave packet, <" separators=" Ψ1 ( 2 ) ( p r ∗ , p u , t ) | , that is prepared on the lower electronic e1 PES by a broadband (fs) probe pulse, Epr(t), acting on the first-order wave packet. In off-resonant FSRS, |" separators=" Ψ2 ( 1 ) ( p u , t ) > resembles the zeroth order wave packet |" separators=" Ψ1 ( 0 ) ( t ) > on the lower PES spatially, but with a force on |" separators=" Ψ2 ( 1 ) ( p u , t ) > along the coordinates of the reporter modes due to displacements in the equilibrium position, so that <" separators=" Ψ1 ( 2 ) ( p r ∗ , p u , t ) | will oscillate along those coordinates thus giving rise to similar oscillations in P(3)(t) with the frequencies of the reporter modes. So, by recovering P(3)(t) from the FSRS spectrum, we are able to deduce information on the time-dependent quantum-mechanical wave packet averaged frequencies, ω ¯ j ( t ) , of the reporter modes j along the trajectory of |" separators=" Ψ1 ( 0 ) ( t ) > . The observable FSRS Raman gain is related to the imaginary part of P(3)(ω). The imaginary and real parts of P(3)(ω) are related by the Kramers-Kronig relation. Hence, from the FSRS Raman gain, we can obtain the complex P(3)(ω), whose Fourier transform then gives us the complex P(3)(t) to analyze for ω ¯ j ( t ) . We apply the theory, first, to a two-dimensional model system with one conformational mode of low frequency and one reporter vibrational mode of higher frequency with good results, and then we apply it to the time-resolved FSRS spectra of the cis-trans isomerization of retinal in rhodopsin [P. Kukura et al., Science 310, 1006 (2005)]. We obtain the vibrational

  17. Deep seafloor arrivals: an unexplained set of arrivals in long-range ocean acoustic propagation.

    PubMed

    Stephen, Ralph A; Bolmer, S Thompson; Dzieciuch, Matthew A; Worcester, Peter F; Andrew, Rex K; Buck, Linda J; Mercer, James A; Colosi, John A; Howe, Bruce M

    2009-08-01

    Receptions, from a ship-suspended source (in the band 50-100 Hz) to an ocean bottom seismometer (about 5000 m depth) and the deepest element on a vertical hydrophone array (about 750 m above the seafloor) that were acquired on the 2004 Long-Range Ocean Acoustic Propagation Experiment in the North Pacific Ocean, are described. The ranges varied from 50 to 3200 km. In addition to predicted ocean acoustic arrivals and deep shadow zone arrivals (leaking below turning points), "deep seafloor arrivals," that are dominant on the seafloor geophone but are absent or very weak on the hydrophone array, are observed. These deep seafloor arrivals are an unexplained set of arrivals in ocean acoustics possibly associated with seafloor interface waves.

  18. Wireless Avionics Packet to Support Fault Tolerance for Flight Applications

    NASA Technical Reports Server (NTRS)

    Block, Gary L.; Whitaker, William D.; Dillon, James W.; Lux, James P.; Ahmad, Mohammad

    2009-01-01

    In this protocol and packet format, data traffic is monitored by all network interfaces to determine the health of transmitter and subsystems. When failures are detected, the network inter face applies its recover y policies to provide continued service despite the presence of faults. The protocol, packet format, and inter face are independent of the data link technology used. The current demonstration system supports both commercial off-the-shelf wireless connections and wired Ethernet connections. Other technologies such as 1553 or serial data links can be used for the network backbone. The Wireless Avionics packet is divided into three parts: a header, a data payload, and a checksum. The header has the following components: magic number, version, quality of service, time to live, sending transceiver, function code, payload length, source Application Data Interface (ADI) address, destination ADI address, sending node address, target node address, and a sequence number. The magic number is used to identify WAV packets, and allows the packet format to be updated in the future. The quality of service field allows routing decisions to be made based on this value and can be used to route critical management data over a dedicated channel. The time to live value is used to discard misrouted packets while the source transceiver is updated at each hop. This information is used to monitor the health of each transceiver in the network. To identify the packet type, the function code is used. Besides having a regular data packet, the system supports diagnostic packets for fault detection and isolation. The payload length specifies the number of data bytes in the payload, and this supports variable-length packets in the network. The source ADI is the address of the originating interface. This can be used by the destination application to identify the originating source of the packet where the address consists of a subnet, subsystem class within the subnet, a subsystem unit

  19. First in line or first in time? Effects of settlement order and arrival date on reproduction in a group-living beetle Dendroctonus ponderosae.

    PubMed

    Latty, Tanya M; Reid, Mary L

    2009-05-01

    1. In group-living organisms, individuals that initiate aggregations, termed pioneers, may suffer higher mortality costs than individuals that join established aggregations. Here we examine the hypothesis that aggregation initiators achieve higher reproductive success in the early phases of colonization, potentially through lower competition and increased access to the resource (finder's advantage), and that this benefit is sufficient to outweigh the costs of pioneering. 2. We also examine the role of arrival date (irrespective of order within the aggregation) on reproductive success, because individuals in seasonal environments may gain an advantage by arriving early. We test these hypotheses using mountain pine beetles, Dendroctonus ponderosae (Coleoptera: Curculionidae, Scolytinae), an obligately aggregating insect wherein pioneers suffer high mortality due to tree defences. We measured reproductive success at the start of winter when most components of final offspring number were likely to be determined. 3. Surviving pioneers that successfully recruited conspecifics had smaller broods than individuals that joined aggregations, refuting our hypothesis. The later that a beetle settled within an aggregation, the higher its reproductive success. However, beetles that settled early in the season produced more offspring than those that settled later in the season, and this effect was generally stronger than settlement order within an aggregation. Our study highlights the importance of examining the effects of both settlement order and arrival date on the costs and benefits of pioneering aggregations.

  20. Exact Results for `Bouncing' Gaussian Wave Packets

    NASA Astrophysics Data System (ADS)

    Belloni, M.; Doncheski, M. A.; Robinett, R. W.

    2005-01-01

    We consider time-dependent Gaussian wave packet solutions of the Schrödinger equation, with arbitrary initial central position, x0, and momentum, p0, for an otherwise free particle, but with an infinite wall at x = 0, so-called bouncing wave packets. We show how difference or mirror solutions of the form ψ(x,t) - ψ(-x,t) can, in this case, be normalized exactly, allowing for the evaluation of a number of time-dependent expectation values and other quantities in closed form. For example, we calculate langp2rangt explicitly which illustrates how the free-particle kinetic (and hence total energy) is affected by the presence of the distant boundary. We also discuss the time dependence of the expectation values of position, langxrangt, and momentum, langprangt, and their relation to the impulsive force during the `collision' with the wall. Finally, the x0, p0 → 0 limit is shown to reduce a special case of a non-standard free-particle Gaussian solution. The addition of this example to the literature then expands of the relatively small number of Gaussian solutions to quantum mechanical problems with familiar classical analogs (free particle, uniform acceleration, harmonic oscillator, unstable oscillator, and uniform magnetic field) available in closed form.

  1. Per-packet reservation MAC protocols

    NASA Astrophysics Data System (ADS)

    Hrasnica, Halid

    2006-10-01

    Recent and future communications networks have to provide QoS guarantees for a rapidly growing number of various telecommunications services. Therefore, various communications systems, such as wireless and fixed access networks, apply reservation MAC protocols, providing a good network utilization, which is particularly important access networks with typically limited data rates, and ensuring realization of different QoS guarantees for various telecommunications services. This is important because of a hard competition among communications technologies applied in the access area. The considered MAC protocols apply a per-packet reservation method to avoid the transmission gaps caused by per-burst reservation, and accordingly to achieve a better network utilization. However, the per-packet reservation increases the network load caused by the signaling, which calls for an efficient resource sharing strategy in the signaling channel. There are two basic solutions for capacity sharing in the signaling channel: random access, usually using slotted ALOHA, and dedicated access, realized by a polling method. Performance improvement of basic protocols can be carried out in different ways; by protocol extensions, a combination of different protocol solutions, and the application of adaptive protocols providing a change of access parameters according to the current network status. The best network performance is achieved by application of two-step reservation protocol, which combined with additional features, such as appropriate signaling procedure, priority and fairness mechanisms, and combined reservation domains, can fulfill requirements of services with high QoS demands.

  2. F-16: The Arrival of NASA 516

    NASA Technical Reports Server (NTRS)

    1991-01-01

    NASA 516, NASA Langley's F-16A Research Support Aircraft is shown on arrival at the center in late summer of 1991. Delivered from Eglin AFB, NASA 516 provided an advanced fighter capability for Langley research pilots in support of advanced Fighter Research Programs at the center.

  3. Time of arrival in quantum mechanics

    SciTech Connect

    Grot, N.; Rovelli, C.; Tate, R.S.

    1996-12-01

    We study the problem of computing the probability for the time of arrival of a quantum particle at a given spatial position. We consider a solution to this problem based on the spectral decomposition of the particle{close_quote}s (Heisenberg) state into the eigenstates of a suitable operator, which we denote as the {open_quote}{open_quote}time-of-arrival{close_quote}{close_quote} operator. We discuss the general properties of this operator. We construct the operator explicitly in the simple case of a free nonrelativistic particle and compare the probabilities it yields with the ones estimated indirectly in terms of the flux of the Schr{umlt o}dinger current. We derive a well-defined uncertainty relation between time of arrival and energy; this result shows that the well-known arguments against the existence of such a relation can be circumvented. Finally, we define a {open_quote}{open_quote}time representation{close_quote}{close_quote} of the quantum mechanics of a free particle, in which the time of arrival is diagonal. Our results suggest that, contrary to what is commonly assumed, quantum mechanics exhibits a hidden equivalence between independent (time) and dependent (position) variables, analogous to the one revealed by the parametrized formalism in classical mechanics. {copyright} {ital 1996 The American Physical Society.}

  4. 14 CFR 93.23 - Arrival Authorizations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Arrival Authorizations. 93.23 Section 93.23 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR TRAFFIC AND GENERAL OPERATING RULES SPECIAL AIR TRAFFIC RULES Congestion and Delay Reduction at Chicago...

  5. Wake Turbulence Mitigation for Arrivals (WTMA)

    NASA Technical Reports Server (NTRS)

    Williams, Daniel M.; Lohr, Gary W.; Trujillo, Anna C.

    2008-01-01

    The preliminary Wake Turbulence Mitigation for Arrivals (WTMA) concept of operations is described in this paper. The WTMA concept provides further detail to work initiated by the Wake Vortex Avoidance System Concept Evaluation Team and is an evolution of the Wake Turbulence Mitigation for Departure concept. Anticipated benefits about reducing wake turbulence separation standards in crosswind conditions, and candidate WTMA system considerations are discussed.

  6. HELCATS Prediction of Planetary CME arrival times

    NASA Astrophysics Data System (ADS)

    Boakes, Peter; Moestl, Christian; Davies, Jackie; Harrison, Richard; Byrne, Jason; Barnes, David; Isavnin, Alexey; Kilpua, Emilia; Rollett, Tanja

    2015-04-01

    We present the first results of CME arrival time prediction at different planetary locations and their comparison to the in situ data within the HELCATS project. The EU FP7 HELCATS (Heliospheric Cataloguing, Analysis & Techniques Service) is a European effort to consolidate the exploitation of the maturing field of heliospheric imaging. HELCATS aims to catalogue solar wind transients, observed by the NASA STEREO Heliospheric Imager (HI) instruments, and validate different methods for the determination of their kinematic properties. This validation includes comparison with arrivals at Earth, and elsewhere in the heliosphere, as well as onsets at the Sun (http://www.helcats-fp7.eu/). A preliminary catalogue of manually identified CMEs, with over 1000 separate events, has been created from observations made by the STEREO/HI instruments covering the years 2007-2013. Initial speeds and directions of each CME have been derived through fitting the time elongation profile to the state of the art Self-Similar Expansion Fitting (SSEF) geometric technique (Davies et al., 2012). The technique assumes that, in the plane corresponding to the position angle of interest, CMEs can be modelled as circles subtending a fixed angular width to Sun-center and propagating anti-sunward in a fixed direction at a constant speed (we use an angular width of 30 degrees in our initial results). The model has advantages over previous geometric models (e.g. harmonic mean or fixed phi) as it allows one to predict whether a CME will 'hit' a specific heliospheric location, as well as to what degree (e.g. direct assault or glancing blow). We use correction formulae (Möstl and Davies, 2013) to convert CME speeds, direction and launch time to speed and arrival time at any in situ location. From the preliminary CME dataset, we derive arrival times for over 400 Earth-directed CMEs, and for over 100 Mercury-, Venus-, Mars- and Saturn-directed CMEs predicted to impact each planet. We present statistics of

  7. Nature's Hitchhikers. A Fall Activity Packet for Second Grade.

    ERIC Educational Resources Information Center

    Jackson Community Coll., MI. Dahlem Environmental Education Center.

    This instructional packet is one of 14 school environmental education programs developed for use in the classroom and at the Dahlem Environmental Education Center (DEEC) of the Jackson Community College (Michigan). Provided in the packet are pre-trip activities, field trip activities, and post-trip activities which focus on the characteristics of…

  8. Responding to Crisis at a School. A Resource Aid Packet.

    ERIC Educational Resources Information Center

    California Univ., Los Angeles. Center for Mental Health Schools.

    Schools are increasingly confronted with crisis events. This resource aid packet provides materials to facilitate planning and implementation of a school-based crisis response and related staff training. The packet is divided into four sections. The first offers a brief overview that can be shared with school staff to raise awareness about the…

  9. Spring Birds. A Spring Activity Packet for First Grade.

    ERIC Educational Resources Information Center

    Jackson Community Coll., MI. Dahlem Environmental Education Center.

    This instructional packet is one of 14 school environmental education programs developed for use in the classroom and at the Dahlem Environmental Education Center (DEEC) of the Jackson Community College (Michigan). Provided in the packet are pre-trip activities, field trip activities, and post-trip activities which focus on the characteristics of…

  10. Reading the Rocks. A Fall Activity Packet for Fifth Grade.

    ERIC Educational Resources Information Center

    Jackson Community Coll., MI. Dahlem Environmental Education Center.

    This instructional packet is one of 14 school environmental education programs developed for use in the classroom and at the Dahlem Environmental Education Center (DEEC) of the Jackson Community College (Michigan). Provided in the packet are pre-trip activities, field trip activities, and post-trip activities which focus on various geological…

  11. Frogs and Toads. A Spring Activity Packet for Second Grade.

    ERIC Educational Resources Information Center

    Jackson Community Coll., MI. Dahlem Environmental Education Center.

    This instructional packet is one of 14 school environmental education programs developed for use in the classroom and at the Dahlem Environmental Education Center (DEEC) of the Jackson Community College (Michigan). Provided in the packet are pre-trip activities, field trip activities, and post-trip activities which focus on the characteristics and…

  12. Understanding and Minimizing Staff Burnout. An Introductory Packet.

    ERIC Educational Resources Information Center

    California Univ., Los Angeles. Center for Mental Health Schools.

    Staff who bring a mental health perspective to the schools can deal with problems of staff burnout. This packet is designed to help in beginning the process of minimizing burnout, a process that requires reducing environmental stressors, increasing personal capabilities, and enhancing job supports. The packet opens with brief discussions of "What…

  13. Continuing Development of California State Packet Radio Project.

    ERIC Educational Resources Information Center

    Brownrigg, Edwin

    1992-01-01

    Provides background on the California State Library Packet Radio project, which will use packet radios to deploy a wireless, high-speed, wide-area network of 600 nodes, including 100 libraries, in the San Francisco Bay Area. Project goals and objectives, plan of operation, equipment, and evaluation plans are summarized. (MES)

  14. Learn about Seabirds. Teaching Packet, Grades 4-6.

    ERIC Educational Resources Information Center

    Fish and Wildlife Service (Dept. of Interior), Anchorage, AK.

    This teaching packet is designed to teach Alaskan students in grades 4-6 about Alaska's seabird populations, the worldwide significance of seabirds, and the environmental conditions to which seabirds are sensitive. The packet includes a curriculum guide (containing a teacher's background story and 12 teaching activities), a separately published…

  15. Forests and Flowers. A Spring Activity Packet for Third Grade.

    ERIC Educational Resources Information Center

    Jackson Community Coll., MI. Dahlem Environmental Education Center.

    This instructional packet is one of 14 school environmental education programs developed for use in the classroom and at the Dahlem Environmental Education Center (DEEC) of the Jackson Community College (Michigan). Provided in the packet are pre-trip activities, field trip activities, and post-trip activities which focus on plants and…

  16. Student Activity Packet for the California State Capitol Museum.

    ERIC Educational Resources Information Center

    2001

    This packet contains materials to help fourth and fifth grade teachers provide their students with background information for field trips to the California State Capitol Museum (Sacramento). The working museum focuses on the theme areas of California history, the state government/legislative process, and state symbols. The packet presents teacher…

  17. Nature Prepares for Winter. A Fall Activity Packet for Kindergarten.

    ERIC Educational Resources Information Center

    Jackson Community Coll., MI. Dahlem Environmental Education Center.

    This instructional packet is one of 14 school environmental education programs developed for use in the classroom and at the Dahlem Environmental Education Center (DEEC) of the Jackson Community College (Michigan). Provided in the packet are pre-trip activities, field trip activities, and post-trip activities which focus on preparations for winter…

  18. Energy Around Us. A Fall Activity Packet for Fourth Grade.

    ERIC Educational Resources Information Center

    Jackson Community Coll., MI. Dahlem Environmental Education Center.

    This instructional packet is one of 14 school environmental education programs developed for use in the classroom and at the Dahlem Environmental Education Center (DEEC) of the Jackson Community College (Michigan). Provided in the packet are pre-trip activities, field trip activities, and post-trip activities which focus on energy uses, energy…

  19. Michigan Natural History. A Spring Activity Packet for Fourth Grade.

    ERIC Educational Resources Information Center

    Jackson Community Coll., MI. Dahlem Environmental Education Center.

    This instructional packet is one of 14 school environmental education programs developed for use in the classroom and at the Dahlem Environmental Education Center (DEEC) of the Jackson Community College (Michigan). Provided in the packet are pre-trip activities, field trip activities, and post-trip activities which focus on the natural history of…

  20. Langston Hughes Curriculum Packet: Dig and Be Dug in Return.

    ERIC Educational Resources Information Center

    Danielson, Susan

    Designed in a flexible format for use by college instructors, high school teachers, and community education workers, this curriculum packet serves as an introduction to the life and works of black poet Langston Hughes. The major component of the packet is a critical essay that explores the thematic highlights of Hughes's career. The remaining…

  1. The preadmission packet: a strategy that benefits patients and nurses during the admission process.

    PubMed

    Keithly, Sherry; Muldoon, Mary; Cheng, Dunlei; Vish, Nancy; Dejong, Sandra McLeroy; Adams, Jenny

    2011-10-01

    At Baylor Jack and Jane Hamilton Heart and Vascular Hospital, we developed a preadmission packet that is given to patients before their procedure date, enabling them to complete much of their paperwork in advance. The results of our subsequent study revealed that nurses save time during the assessment interview when patients arrive at the hospital with their admission database forms completed. In a busy facility with a large number of patients admitted daily, the nursing time saved can translate into a substantial economic benefit. Even more important, however, is the benefit to patients, who feel less rushed and provide a more thorough and accurate medical history when they can fill out the admission database form at home.

  2. Jump state estimation with multiple sensors with packet dropping and delaying channels

    NASA Astrophysics Data System (ADS)

    Dolz, Daniel; Peñarrocha, Ignacio; Sanchis, Roberto

    2016-03-01

    This work addresses the design of a state observer for systems whose outputs are measured through a communication network. The measurements from each sensor node are assumed to arrive randomly, scarcely and with a time-varying delay. The proposed model of the plant and the network measurement scenarios cover the cases of multiple sensors, out-of-sequence measurements, buffered measurements on a single packet and multirate sensor measurements. A jump observer is proposed that selects a different gain depending on the number of periods elapsed between successfully received measurements and on the available data. A finite set of gains is pre-calculated offline with a tractable optimisation problem, where the complexity of the observer implementation is a design parameter. The computational cost of the observer implementation is much lower than in the Kalman filter, whilst the performance is similar. Several examples illustrate the observer design for different measurement scenarios and observer complexity and show the achievable performance.

  3. Relaxation of an electron wave packet at the quantum Hall edge at filling factor ν =2

    NASA Astrophysics Data System (ADS)

    Slobodeniuk, Artur O.; Idrisov, Edvin G.; Sukhorukov, Eugene V.

    2016-01-01

    We address the recent experiment (S. Tewari et al., Phys. Rev. B 93, 035420 (2016), 10.1103/PhysRevB.93.035420) where the suppression of phase coherence of a single-electron wave packet created at the edge of a quantum Hall (QH) system at filling factor 2 has been investigated with the help of an electronic Mach-Zehnder (MZ) interferometer. The authors of the experiment have observed an unexpected behavior of phase coherence that saturates at high energies instead of vanishing, presumably suggesting the relaxation of a wave packet to the ground state before it arrives to the MZ interferometer. Here, we theoretically investigate this situation using the model of edge states [I. P. Levkivskyi and E. V. Sukhorukov, Phys. Rev. B 78, 045322 (2008), 10.1103/PhysRevB.78.045322], which accounts for the strong Coulomb interaction between the two electron channels at the edge of a QH system. We conclude that the observed phenomenon cannot be explained within this model for the reason that under an assumption of linearity of the electron spectrum at low energies, the system remains integrable in terms of the collective charge excitations and therefore full relaxation to the ground state is not possible, despite strong interactions. As a result, the degree of the phase coherence decreases with the energy of the initial state in a power-law manner. Since this does not happen in the experiment, a different physical phenomenon may take place at the edge of a QH state, which deserves further investigation. We support our findings by calculating the energy distribution and the Wigner function of the outgoing nonequilibrium state of the single-electron wave packet.

  4. Learning packets in nursing education: reviving the past.

    PubMed

    Xu, Yin; Martin, Madeleine; Gribbins, Ashley

    2010-05-01

    Learning packets gained popularity in nursing education in the 1960's. Recently, they have been cited as strategies for distance learning. The aim of this project was to integrate Topic Focused Learning Packets as a complementary teaching strategy for presentation of new content to large classes of undergraduate nursing students. In addition to reducing in-class content presentation time, goals included: fostering critical thinking, actively engaging the student, and providing opportunities for team-based interaction. Rationale, design process and packets will be described. The learning packet was viewed positively by the students and faculty. Among 134 students, 119 strongly agreed or agreed that the learning packet was effective in increasing their understanding of the content and achieving the course objectives.

  5. The ESA standard for telemetry and telecommand packet utilisation: PUS

    NASA Technical Reports Server (NTRS)

    Kaufeler, Jean-Francois

    1994-01-01

    ESA has developed standards for packet telemetry and telecommand, which are derived from the recommendations of the Inter-Agency Consultative Committee for Space Data Systems (CCSDS). These standards are now mandatory for future ESA programs as well as for many programs currently under development. However, while these packet standards address the end-to-end transfer of telemetry and telecommand data between applications on the ground and Application Processes on-board, they leave open the internal structure or content of the packets. This paper presents the ESA Packet Utilization Standard (PUS) which addresses this very subject and, as such, serves to extend and complement the ESA packet standards. The goal of the PUS is to be applicable to future ESA missions in all application areas (Telecommunications, Science, Earth Resources, microgravity, etc.). The production of the PUS falls under the responsibility of the ESA Committee for Operations and EGSE Standards (COES).

  6. Theory for low-frequency modulated Langmuir wave packets

    NASA Technical Reports Server (NTRS)

    Cairns, Iver H.; Robinson, P. A.

    1992-01-01

    Langmuir wave packets with low frequency modulations (or beats) observed in the Jovian foreshock are argued to be direct evidence for the Langmuir wave decay L yields L-prime + S. In this decay, 'pump' Langmuir waves L, driven by an electron beam, produce backscattered product Langmuir waves L-prime and ion sound waves S. The L and L-prime waves beat at the frequency and wavevector of the S waves, thereby modulating the wave packets. Beam speeds calculated using the modulated Jovian wave packets (1) are reasonable, at 4-10 times the electron thermal speed, (2) are consistent with theoretical limits on the decay process, and (3) decrease with increasing foreshock depth, as expected theoretically. These results strongly support the theory. The modulation depth of some wave packets suggests saturation by the decay L yields L-prime + S. Applications to modulated Langmuir packets in the Venusian and terrestrial foreshocks and in a type III radio source are proposed.

  7. Nondiffracting accelerating wave packets of Maxwell's equations.

    PubMed

    Kaminer, Ido; Bekenstein, Rivka; Nemirovsky, Jonathan; Segev, Mordechai

    2012-04-20

    We present the nondiffracting spatially accelerating solutions of the Maxwell equations. Such beams accelerate in a circular trajectory, thus generalizing the concept of Airy beams to the full domain of the wave equation. For both TE and TM polarizations, the beams exhibit shape-preserving bending which can have subwavelength features, and the Poynting vector of the main lobe displays a turn of more than 90°. We show that these accelerating beams are self-healing, analyze their properties, and find the new class of accelerating breathers: self-bending beams of periodically oscillating shapes. Finally, we emphasize that in their scalar form, these beams are the exact solutions for nondispersive accelerating wave packets of the most common wave equation describing time-harmonic waves. As such, this work has profound implications to many linear wave systems in nature, ranging from acoustic and elastic waves to surface waves in fluids and membranes. PMID:22680719

  8. Nondiffracting accelerating wave packets of Maxwell's equations.

    PubMed

    Kaminer, Ido; Bekenstein, Rivka; Nemirovsky, Jonathan; Segev, Mordechai

    2012-04-20

    We present the nondiffracting spatially accelerating solutions of the Maxwell equations. Such beams accelerate in a circular trajectory, thus generalizing the concept of Airy beams to the full domain of the wave equation. For both TE and TM polarizations, the beams exhibit shape-preserving bending which can have subwavelength features, and the Poynting vector of the main lobe displays a turn of more than 90°. We show that these accelerating beams are self-healing, analyze their properties, and find the new class of accelerating breathers: self-bending beams of periodically oscillating shapes. Finally, we emphasize that in their scalar form, these beams are the exact solutions for nondispersive accelerating wave packets of the most common wave equation describing time-harmonic waves. As such, this work has profound implications to many linear wave systems in nature, ranging from acoustic and elastic waves to surface waves in fluids and membranes.

  9. Networked LQG control over lossy channels with computational/packet-transmission delays and coarsely quantised packets

    NASA Astrophysics Data System (ADS)

    Foo, Yung Kuan; Moayedi, Maryam; Chai Soh, Yeng

    2016-04-01

    This article addresses the linear quadratic Gaussian (LQG) control problem of networked multi-input, multi-output systems where computational delay exists and the measurement and control signals are packetised and transmitted through a network within which random delay and packet loss may occur during transmissions. A transmission control protocol (TCP)-like protocol for the communication network is considered in which acknowledgement is sent from the actuator to the controller if and only if the control packet is received, assuming these acknowledgements always reach the estimator in time and without fail. To minimise the data word-length for transmissions over the network and to maximise control system performance, it is proposed that different quantisation resolutions be used for transmission data encapsulation, and control and output signals A/D-D/A conversions at sensor/actuator. To circumvent the problem of disparity between encapsulation and A/D-D/A quantisation resolutions, a pseudo-stochastic approach via subtractive dither is applied to quantise the transmission packets. This also enables us to model the quantisation errors as uncorrelated independent zero-mean additive white noises and apply standard LQG methodology and separation principle to design the estimator and the controller separately. An example is included to demonstrate the effectiveness of the approach.

  10. Knowledge-based scheduling of arrival aircraft

    NASA Technical Reports Server (NTRS)

    Krzeczowski, K.; Davis, T.; Erzberger, H.; Lev-Ram, I.; Bergh, C.

    1995-01-01

    A knowledge-based method for scheduling arrival aircraft in the terminal area has been implemented and tested in real-time simulation. The scheduling system automatically sequences, assigns landing times, and assigns runways to arrival aircraft by utilizing continuous updates of aircraft radar data and controller inputs. The scheduling algorithms is driven by a knowledge base which was obtained in over two thousand hours of controller-in-the-loop real-time simulation. The knowledge base contains a series of hierarchical 'rules' and decision logic that examines both performance criteria, such as delay reduction, as well as workload reduction criteria, such as conflict avoidance. The objective of the algorithms is to devise an efficient plan to land the aircraft in a manner acceptable to the air traffic controllers. This paper will describe the scheduling algorithms, give examples of their use, and present data regarding their potential benefits to the air traffic system.

  11. STS-85 Crew Arrival for TCDT

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The Space Shuttle Mission STS-85 crew arrives at the Shuttle Landing Facility for their mission's Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. They are (from left): Mission Specialist Stephen K. Robinson; Payload Commander N. Jan Davis; Mission Specialist Robert L. Curbeam; Commander Curtis L. Brown, Jr.; Pilot Kent V. Rominger; and Payload Specialist Bjarni V. Tryggvason. The liftoff for STS-85 is targeted for August 7, 1997.

  12. Semiautomated Management Of Arriving Air Traffic

    NASA Technical Reports Server (NTRS)

    Erzberger, Heinz; Nedell, William

    1992-01-01

    System of computers, graphical workstations, and computer programs developed for semiautomated management of approach and arrival of numerous aircraft at airport. System comprises three subsystems: traffic-management advisor, used for controlling traffic into terminal area; descent advisor generates information integrated into plan-view display of traffic on monitor; and final-approach-spacing tool used to merge traffic converging on final approach path while making sure aircraft are properly spaced. Not intended to restrict decisions of air-traffic controllers.

  13. STS-80 Crew Arrival (Commander Kenneth Cockrell)

    NASA Technical Reports Server (NTRS)

    1996-01-01

    STS-80 Commander Kenneth D. Cockrell and four fellow crew members arrive at KSC's Shuttle Landing Facility as preparations continue for launch of the final Shuttle flight of 1996. Tomorrow, Nov. 12, the launch countdown will begin at 1 p.m. with the countdown clock set at T-43 hours. The Space Shuttle Columbia is scheduled for liftoff from Launch Pad 39B at 2:50 p.m. EST, Nov. 15.

  14. Instrument for measurement of vacuum in sealed thin wall packets

    DOEpatents

    Kollie, Thomas G.; Thacker, Louis H.; Fine, H. Alan

    1993-01-01

    An instrument for the measurement of vacuum within sealed packets 12, the packets 12 having a wall 14 sufficiently thin that it can be deformed by the application of an external vacuum to small area thereof. The instrument has a detector head 18 for placement against the deformable wall 14 of the packet to apply the vacuum in a controlled manner to accomplish a limited deformation or lift of the wall 14, with this deformation or lift monitored by the application of light as via a bifurcated light pipe 20. Retro-reflected light through the light pipe is monitored with a photo detector 26. An abrupt change (e.g., a decrease) of retro-reflected light signals the wall movement such that the value of the vacuum applied through the head 18 to achieve this initiation of movement is equal to the vacuum Within the packet 12. In a preferred embodiment a vacuum reference plate 44 is placed beneath the packet 12 to ensure that no deformation occurs on the reverse surface 16 of the packet. A packet production line model is also described.

  15. Instrument for measurement of vacuum in sealed thin wall packets

    DOEpatents

    Kollie, T.G.; Thacker, L.H.; Fine, H.A.

    1993-10-05

    An instrument is described for the measurement of vacuum within sealed packets, the packets having a wall sufficiently thin that it can be deformed by the application of an external vacuum to small area thereof. The instrument has a detector head for placement against the deformable wall of the packet to apply the vacuum in a controlled manner to accomplish a limited deformation or lift of the wall, with this deformation or lift monitored by the application of light as via a bifurcated light pipe. Retro-reflected light through the light pipe is monitored with a photo detector. An abrupt change (e.g., a decrease) of retro-reflected light signals the wall movement such that the value of the vacuum applied through the head to achieve this initiation of movement is equal to the vacuum within the packet. In a preferred embodiment a vacuum reference plate is placed beneath the packet to ensure that no deformation occurs on the reverse surface of the packet. A packet production line model is also described. 3 figures.

  16. Rate-matching packet scheduler for real-rate applications

    NASA Astrophysics Data System (ADS)

    Li, Kang; Walpole, Jonathan; McNamee, Dylan; Pu, Calton; Steere, David C.

    2000-12-01

    A packet scheduler is an operating system component that controls the allocation of network interface bandwidth to outgoing network flows. By deciding which packet to send next, packet schedulers not only determine how bandwidth is shared among flows, but also play a key role in determining the rate and timing behavior of individual flows. The recent explosion of rate and timing-sensitive flows, particularly in the context of multimedia applications, has focused new interest on packet schedulers. Next generation packet schedulers must not only ensure separation among flows and meet real-time performance constraints, they must also support dynamic fine- grain real-location of bandwidth for flows with variable-bit- rate requirements. Unfortunately, today's packet schedulers either do not support rate and timing sensitive flows, or do so with reservation systems that are relatively coarse-grain and inflexible. This paper makes two contributions. First it shows how bandwidth requirements can be inferred directly from real-rate flows, without requiring explicit specifications from the application. Second, it presents the design, implementation and performance evaluation of a rate-matching packet scheduler that uses these inferred requirements to automatically and dynamically control the bandwidth allocation to flows.

  17. Reinforcement learning for congestion-avoidance in packet flow

    NASA Astrophysics Data System (ADS)

    Horiguchi, Tsuyoshi; Hayashi, Keisuke; Tretiakov, Alexei

    2005-04-01

    Occurrence of congestion of packet flow in computer networks is one of the unfavorable problems in packet communication and hence its avoidance should be investigated. We use a neural network model for packet routing control in a computer network proposed in a previous paper by Horiguchi and Ishioka (Physica A 297 (2001) 521). If we assume that the packets are not sent to nodes whose buffers are already full of packets, then we find that traffic congestion occurs when the number of packets in the computer network is larger than some critical value. In order to avoid the congestion, we introduce reinforcement learning for a control parameter in the neural network model. We find that the congestion is avoided by the reinforcement learning and at the same time we have good performance for the throughput. We investigate the packet flow on computer networks of various types of topology such as a regular network, a network with fractal structure, a small-world network, a scale-free network and so on.

  18. Observation of Quantum Interference between Separated Mechanical Oscillator Wave Packets

    NASA Astrophysics Data System (ADS)

    Kienzler, D.; Flühmann, C.; Negnevitsky, V.; Lo, H.-Y.; Marinelli, M.; Nadlinger, D.; Home, J. P.

    2016-04-01

    We directly observe the quantum interference between two well-separated trapped-ion mechanical oscillator wave packets. The superposed state is created from a spin-motion entangled state using a heralded measurement. Wave packet interference is observed through the energy eigenstate populations. We reconstruct the Wigner function of these states by introducing probe Hamiltonians which measure Fock state populations in displaced and squeezed bases. Squeezed-basis measurements with 8 dB squeezing allow the measurement of interference for Δ α =15.6 , corresponding to a distance of 240 nm between the two superposed wave packets.

  19. Realization of localized Bohr-like wave packets.

    PubMed

    Mestayer, J J; Wyker, B; Lancaster, J C; Dunning, F B; Reinhold, C O; Yoshida, S; Burgdörfer, J

    2008-06-20

    We demonstrate a protocol to create localized wave packets in very-high-n Rydberg states which travel in nearly circular orbits around the nucleus. Although these wave packets slowly dephase and eventually lose their localization, their motion can be monitored over several orbital periods. These wave packets represent the closest analog yet achieved to the original Bohr model of the hydrogen atom, i.e., an electron in a circular classical orbit around the nucleus. The possible extension of the approach to create "planetary atoms" in highly correlated stable multiply excited states is discussed.

  20. Observation of Quantum Interference between Separated Mechanical Oscillator Wave Packets.

    PubMed

    Kienzler, D; Flühmann, C; Negnevitsky, V; Lo, H-Y; Marinelli, M; Nadlinger, D; Home, J P

    2016-04-01

    We directly observe the quantum interference between two well-separated trapped-ion mechanical oscillator wave packets. The superposed state is created from a spin-motion entangled state using a heralded measurement. Wave packet interference is observed through the energy eigenstate populations. We reconstruct the Wigner function of these states by introducing probe Hamiltonians which measure Fock state populations in displaced and squeezed bases. Squeezed-basis measurements with 8 dB squeezing allow the measurement of interference for Δα=15.6, corresponding to a distance of 240 nm between the two superposed wave packets.

  1. Thermodynamics of Protein Aggregation

    NASA Astrophysics Data System (ADS)

    Osborne, Kenneth L.; Barz, Bogdan; Bachmann, Michael; Strodel, Birgit

    Amyloid protein aggregation characterizes many neurodegenerative disorders, including Alzheimer's, Parkinson's, and Creutz- feldt-Jakob disease. Evidence suggests that amyloid aggregates may share similar aggregation pathways, implying simulation of full-length amyloid proteins is not necessary for understanding amyloid formation. In this study we simulate GNNQQNY, the N-terminal prion-determining domain of the yeast protein Sup35 to investigate the thermodynamics of structural transitions during aggregation. We use a coarse-grained model with replica-exchange molecular dynamics to investigate the association of 3-, 6-, and 12-chain GNNQQNY systems and we determine the aggregation pathway by studying aggregation states of GN- NQQNY. We find that the aggregation of the hydrophilic GNNQQNY sequence is mainly driven by H-bond formation, leading to the formation of /3-sheets from the very beginning of the assembly process. Condensation (aggregation) and ordering take place simultaneously, which is underpinned by the occurrence of a single heat capacity peak only.

  2. All-optical packet header and payload separation based on two TOADs for optical packet switched networks

    NASA Astrophysics Data System (ADS)

    Ji, Wei; Zhang, Min; Ye, Peida

    2006-09-01

    We present a novel all-optical header and payload separation technique that can be utilized in Un-Slotted optical packet switched networks. The technique uses two modified TOADs, one is for packet header extraction with differential modulation scheme and the other performs a simple XOR operation between the packet and its self-derived header to get the separated payload. The main virtue of this system is simple structure and low power consumption. Through numerical simulations, the operating characteristics of the scheme are illustrated. In addition, the system parameters are discussed and designed to optimize the performance of the proposed scheme.

  3. STS-93: Crew Arrival and PR Location

    NASA Technical Reports Server (NTRS)

    1999-01-01

    The primary objective of the STS-93 mission was to deploy the Advanced X-ray Astrophysical Facility, which had been renamed the Chandra X-ray Observatory in honor of the late Indian-American Nobel Laureate Subrahmanyan Chandrasekhar. The mission was launched at 12:31 on July 23, 1999 onboard the space shuttle Columbia. The mission was led by Commander Eileen Collins. The crew was Pilot Jeff Ashby and Mission Specialists Cady Coleman, Steve Hawley and Michel Tognini from the Centre National d'Etudes Spatiales (CNES). This videotape shows the astronauts arriving at Kennedy and an inspection in the clean room.

  4. 19 CFR 122.154 - Notice of arrival.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... AIR COMMERCE REGULATIONS Flights to and From Cuba § 122.154 Notice of arrival. (a) Application. All aircraft entering the U.S. from Cuba must give advance notice of arrival, unless it is an Office of...

  5. Initial phase and free-particle wave packet evolution

    NASA Astrophysics Data System (ADS)

    Beach, Theodore L.

    2009-06-01

    The evolution of the free-particle wave function in one dimension is the same as scalar Fresnel diffraction from a one-dimensional structure. Quantum mechanics courses often explore the propagation of Gaussian wave packets, but the diffractionlike mathematics is sufficiently tractable to investigate the propagation of other wave packets, both numerically and analytically. More importantly, the diffraction analogy facilitates the development of an intuitive understanding of the role that the initial phase plays in free-particle wave packet evolution. This article considers some of the effects of the initial phase function on the subsequent evolution of free-particle wave packets in the position representation. These considerations reinforce the idea that the classical mechanics limit embodied in the correspondence principle and formalized in the Ehrenfest theorem is necessarily an incomplete representation of quantum behavior.

  6. Localization of wave packets in one-dimensional random potentials

    NASA Astrophysics Data System (ADS)

    Valdes, Juan Pablo Ramírez; Wellens, Thomas

    2016-06-01

    We study the expansion of an initially strongly confined wave packet in a one-dimensional weak random potential with short correlation length. At long times, the expansion of the wave packet comes to a halt due to destructive interferences leading to Anderson localization. We develop an analytical description for the disorder-averaged localized density profile. For this purpose, we employ the diagrammatic method of Berezinskii which we extend to the case of wave packets, present an analytical expression of the Lyapunov exponent which is valid for small as well as for high energies, and, finally, develop a self-consistent Born approximation in order to analytically calculate the energy distribution of our wave packet. By comparison with numerical simulations, we show that our theory describes well the complete localized density profile, not only in the tails but also in the center.

  7. Packet-Based Protocol Efficiency for Aeronautical and Satellite Communications

    NASA Technical Reports Server (NTRS)

    Carek, David A.

    2005-01-01

    This paper examines the relation between bit error ratios and the effective link efficiency when transporting data with a packet-based protocol. Relations are developed to quantify the impact of a protocol s packet size and header size relative to the bit error ratio of the underlying link. These relations are examined in the context of radio transmissions that exhibit variable error conditions, such as those used in satellite, aeronautical, and other wireless networks. A comparison of two packet sizing methodologies is presented. From these relations, the true ability of a link to deliver user data, or information, is determined. Relations are developed to calculate the optimal protocol packet size forgiven link error characteristics. These relations could be useful in future research for developing an adaptive protocol layer. They can also be used for sizing protocols in the design of static links, where bit error ratios have small variability.

  8. Analytic approach to the wave packet formalism in oscillation phenomena

    SciTech Connect

    Bernardini, A.E.; Leo, S. de

    2004-09-01

    We introduce an approximation scheme to perform an analytic study of the oscillation phenomena in a pedagogical and comprehensive way. By using Gaussian wave packets, we show that the oscillation is bounded by a time-dependent vanishing function which characterizes the slippage between the mass-eigenstate wave packets. We also demonstrate that the wave packet spreading represents a secondary effect which plays a significant role only in the nonrelativistic limit. In our analysis, we note the presence of a new time-dependent phase and calculate how this additional term modifies the oscillating character of the flavor conversion formula. Finally, by considering box and sine wave packets we study how the choice of different functions to describe the particle localization changes the oscillation probability.

  9. Propagation velocity of Alfven wave packets in a dissipative plasma

    SciTech Connect

    Amagishi, Y.; Nakagawa, H. ); Tanaka, M. )

    1994-09-01

    We have experimentally studied the behavior of Alfven wave packets in a dissipative plasma due to ion--neutral-atom collisions. It is urged that the central frequency of the packet is observed to gradually decrease with traveling distance in the absorption range of frequencies because of a differential damping among the Fourier components, and that the measured average velocity of its peak amplitude is not accounted for by the conventional group velocity, but by the prediction derived by Tanaka, Fujiwara, and Ikegami [Phys. Rev. A 34, 4851 (1986)]. Furthermore, when the initial central frequency is close to the critical frequency in the anomalous dispersion, the wave packet apparently collapses when traveling along the magnetic field; however, we have found that it is decomposed into another two wave packets with the central frequencies being higher or lower than the critical frequency.

  10. Nondispersive wave packets -- control through chaos

    NASA Astrophysics Data System (ADS)

    Buchleitner, Andreas

    2005-05-01

    Nondispersive wave packets were predicted to emerge in periodically driven Rydberg atoms a little more than 10 years ago [1], and have now been observed in the laboratory [2]. I shall illustrate how these robust, generic ``quantum particles'' and their relatives naturally emerge from the theory of chaotic quantum systems [3], and thus open new perspectives for robust quantum control in various experimental settings -- from one and two-electron [4] atoms under periodic or impulsive [5] driving to cold atoms in flashing periodic potentials, possibly amended by harmonic confinement [6]. Besides the fundamental underlying (nonlinear) resonance phenomena also some more subtle properties will be discussed, including open questions within the realm of spectral theory. *[1] A. Buchleitner, thèse de doctorat, Universit'e Paris 6 (1993); I. Bialynicki-Birula, M. Kalinski, and J. H. Eberly, Phys. Rev. Lett. 73, 1777 (1994); D. Delande and A. Buchleitner, Adv. At. Mol. Opt. Phys. 34, 85 (1994). *[2] H. Maeda and T. F. Gallagher, Phys. Rev. Lett. 92, 133004 (2004). *[3] A. Buchleitner, D. Delande, and J. Zakrzewski, Phys. Rep. 386, 409 (2002). *[4] J. Madroñero, PhD thesis, Ludwig-Maximilians-Universität München (2004), http://edoc.ub.uni-muenchen.de/archive/00002187. *[5] D.G. Arb'o et al., Phys. Rev. A 67, 63401 (2003). *[6] A.R.R. de Carvalho and A. Buchleitner, Phys. Rev. Lett. 93, 204101 (2004).

  11. Embedded wavelet packet transform technique for texture compression

    NASA Astrophysics Data System (ADS)

    Li, Jin; Cheng, Po-Yuen; Kuo, C.-C. Jay

    1995-09-01

    A highly efficient texture compression scheme is proposed in this research. With this scheme, energy compaction of texture images is first achieved by the wavelet packet transform, and an embedding approach is then adopted for the coding of the wavelet packet transform coefficients. By comparing the proposed algorithm with the JPEG standard, FBI wavelet/scalar quantization standard and the EZW scheme with extensive experimental results, we observe a significant improvement in the rate-distortion performance and visual quality.

  12. Behavior of a Moist Kelvin Wave Packet with Nonlinear Heating.

    NASA Astrophysics Data System (ADS)

    Wang, Bin; Xue, Yan

    1992-04-01

    The effects of nonlinear (positive only or conditional) heating on moist Kelvin waves are examined with a simple equatorial zonal-plane model describing the gravest baroclinic mode.The unstable perturbation subject to nonlinear beating emerges as a wave packet. A typical amplifying, eastward-moving wave packet is characterized by an asymmetric structure: 1) the ascending branch (wet region) is much narrower than the two descending ones (dry regions); and 2) the circulation cell to the east of the wet region center is smaller and stronger than its counterpart to the west of the center. The wet-dry asymmetry is primarily caused by the nonlinear beating effect, while the east-west asymmetry is a result of the movement of the wave packet relative to mean flow. The existence of Newtonian cooling and Rayleigh friction enhances the structural asymmetries.The unstable wave packet is characterized by two zonal length scales: the ascending branch length (ABL) and total circulation extent (TCE). For a given basic state, the growth rate of a wave packet increases with decreasing ABL or TCE. However, up to a moderate growth rate (order of day1) the energy spectra of all wave packets are dominated by zonal wavenumber one regardless of ABL size. In particular, the slowly growing (low frequency) wave packets normally exhibit TCEs of planetary scale and ABLs of synoptic scale.Observed equatorial intraseasonal disturbances often display a narrow convection region in between two much broader dry regions and a total circulation of planetary scale. These structure and scale characteristics are caused by the effects of nonlinear heating and the cyclic geometry of the equator. It is argued that the unstable disturbance found in numerical experiments (e.g., Lau and Peng; Hayashi and Sumi) is a manifestation of the nonlinear wave packet.

  13. An Exploratory Study of Runway Arrival Procedures: Time Based Arrival and Self-Spacing

    NASA Technical Reports Server (NTRS)

    Houston, Vincent E.; Barmore, Bryan

    2009-01-01

    The ability of a flight crew to deliver their aircraft to its arrival runway on time is important to the overall efficiency of the National Airspace System (NAS). Over the past several years, the NAS has been stressed almost to its limits resulting in problems such as airport congestion, flight delay, and flight cancellation to reach levels that have never been seen before in the NAS. It is predicted that this situation will worsen by the year 2025, due to an anticipated increase in air traffic operations to one-and-a-half to three times its current level. Improved arrival efficiency, in terms of both capacity and environmental impact, is an important part of improving NAS operations. One way to improve the arrival performance of an aircraft is to enable the flight crew to precisely deliver their aircraft to a specified point at either a specified time or specified interval relative to another aircraft. This gives the flight crew more control to make the necessary adjustments to their aircraft s performance with less tactical control from the controller; it may also decrease the controller s workload. Two approaches to precise time navigation have been proposed: Time-Based Arrivals (e.g., required times of arrival) and Self-Spacing. Time-Based Arrivals make use of an aircraft s Flight Management System (FMS) to deliver the aircraft to the runway threshold at a given time. Self-Spacing enables the flight crew to achieve an ATC assigned spacing goals at the runway threshold relative to another aircraft. The Joint Planning and Development Office (JPDO), a multi-agency initiative established to plan and coordinate the development of the Next Generation Air Transportation System (NextGen), has asked for data for both of these concepts to facilitate future research and development. This paper provides a first look at the delivery performance of these two concepts under various initial and environmental conditions in an air traffic simulation environment.

  14. Instrument for measurement of vacuum in sealed thin wall packets

    DOEpatents

    Kollie, T.G.; Thacker, L.H.; Fine, H.A.

    1995-04-18

    An instrument is disclosed for the measurement of vacuum within sealed packets, the packets having a wall that it can be deformed by the application of an external dynamic vacuum to an area thereof. The instrument has a detector head for placement against the deformable wall of the packet to apply the vacuum in a controlled manner to accomplish a limited deformation or lift of the wall with this deformation or lift monitored by the application of light as via a bifurcated light pipe. Retro-reflected light through the light pipe is monitored with a photo detector. A change (e.g., a decrease) of retro-reflected light signals the wall movement such that the value of the dynamic vacuum applied through the head be to achieve this initiation of movement is equal to the vacuum within the packet. In a preferred embodiment a vacuum plate is placed beneath the packet to ensure that no deformation occurs on the reverse surface of the packet. A vacuum can be applied to a recess in this vacuum plate, the value of which can be used to calibrate the vacuum transducer in the detector head. 4 figs.

  15. Instrument for measurement of vacuum in sealed thin wall packets

    DOEpatents

    Kollie, Thomas G.; Thacker, Louis H.; Fine, H. Alan

    1995-01-01

    An instrument for the measurement of vacuum within sealed packets 12, the packets 12 having a wall 14 that it can be deformed by the application of an external dynamic vacuum to an area thereof. The instrument has a detector head 18 for placement against the deformable wall 14 of the packet to apply the vacuum in a controlled manner to accomplish a limited deformation or lift of the wall 14, with this deformation or lift monitored by the application of light as via a bifurcated light pipe 20. Retro-reflected light through the light pipe is monitored with a photo detector 26. A change (e.g., a decrease) of retro-reflected light signals the wall movement such that the value of the dynamic vacuum applied through the head be to achieve this initiation of movement is equal to the vacuum within the packet 12. In a preferred embodiment a vacuum plate 44 is placed beneath the packet 12 to ensure that no deformation occurs on the reverse surface 16 of the packet. A vacuum can be applied to a recess in this vacuum plate, the value of which can be used to calibrate the vacuum transducer in the detector head.

  16. TCP Packet Trace Analysis. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Shepard, Timothy J.

    1991-01-01

    Examination of a trace of packets collected from the network is often the only method available for diagnosing protocol performance problems in computer networks. This thesis explores the use of packet traces to diagnose performance problems of the transport protocol TCP. Unfortunately, manual examination of these traces can be so tedious that effective analysis is not possible. The primary contribution of this thesis is a graphical method of displaying the packet trace which greatly reduce, the tediousness of examining a packet trace. The graphical method is demonstrated by the examination of some packet traces of typical TCP connections. The performance of two different implementations of TCP sending data across a particular network path is compared. Traces many thousands of packets long are used to demonstrate how effectively the graphical method simplifies examination of long complicated traces. In the comparison of the two TCP implementations, the burstiness of the TCP transmitter appeared to be related to the achieved throughput. A method of quantifying this burstiness is presented and its possible relevance to understanding the performance of TCP is discussed.

  17. Packet utilisation definitions for the ESA XMM mission

    NASA Technical Reports Server (NTRS)

    Nye, H. R.

    1994-01-01

    XMM, ESA's X-Ray Multi-Mirror satellite, due for launch at the end of 1999 will be the first ESA scientific spacecraft to implement the ESA packet telecommand and telemetry standards and will be the first ESOC-controlled science mission to take advantage of the new flight control system infrastructure development (based on object-oriented design and distributed-system architecture) due for deployment in 1995. The implementation of the packet standards is well defined at packet transport level. However, the standard relevant to the application level (the ESA Packet Utilization Standard) covers a wide range of on-board 'services' applicable in varying degrees to the needs of XMM. In defining which parts of the ESA PUS to implement, the XMM project first considered the mission objectives and the derived operations concept and went on to identify a minimum set of packet definitions compatible with these aspects. This paper sets the scene as above and then describes the services needed for XMM and the telecommand and telemetry packet types necessary to support each service.

  18. Time arrival of slab avalanche masses

    NASA Astrophysics Data System (ADS)

    McClung, D. M.

    2003-10-01

    One of three criteria to demonstrate self-organized criticality (SOC) for a critical phenomenon is that time arrival of events displays a frequency dependence which is inversely proportional to frequency (f) to some power. That is, for SOC, the power spectrum in the frequency (f) domain is supposed to fall off as 1/fβ, where β is typically a number between 1 and 2. Avalanche phenomena have been used as prototypes for illustrating SOC, and therefore it is of interest as to whether snow avalanches follow the criterion. In this paper, time series analyses of mass arrivals from 20 years of records constituting ˜10,000 avalanches are presented for Bear Pass and Kootenay Pass, British Columbia. The results suggest that the autocorrelation functions and partial autocorrelation functions of the series fall off in an exponential manner so that the implied power spectra in the frequency domain, given by the Fourier transforms of the autocorrelation functions, decay with frequency in a manner which is not strictly consistent with SOC. In common with SOC, the power spectra are suggested to have most content in the low-frequency events and the spectra do not constitute white noise. However, given the limitations on the data sampling and recording, it cannot be definitively stated that the power spectra fall off with 1/f® as required for SOC.

  19. 33 CFR 146.405 - Safety and Security notice of arrival for vessels arriving at a place on the OCS.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... submitting an NOA: (1) All the information specified in 33 CFR Table 160.206 with the exception of... arrival for vessels arriving at a place on the OCS. 146.405 Section 146.405 Navigation and Navigable... vessels arriving at a place on the OCS. (a) General. The owner or operator of each vessel subject to...

  20. 33 CFR 146.405 - Safety and Security notice of arrival for vessels arriving at a place on the OCS.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... submitting an NOA: (1) All the information specified in 33 CFR Table 160.206 with the exception of... arrival for vessels arriving at a place on the OCS. 146.405 Section 146.405 Navigation and Navigable... vessels arriving at a place on the OCS. (a) General. The owner or operator of each vessel subject to...

  1. 33 CFR 146.405 - Safety and Security notice of arrival for vessels arriving at a place on the OCS.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... submitting an NOA: (1) All the information specified in 33 CFR Table 160.206 with the exception of... arrival for vessels arriving at a place on the OCS. 146.405 Section 146.405 Navigation and Navigable... vessels arriving at a place on the OCS. (a) General. The owner or operator of each vessel subject to...

  2. 33 CFR 146.405 - Safety and Security notice of arrival for vessels arriving at a place on the OCS.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... submitting an NOA: (1) All the information specified in 33 CFR Table 160.206 with the exception of... arrival for vessels arriving at a place on the OCS. 146.405 Section 146.405 Navigation and Navigable... vessels arriving at a place on the OCS. (a) General. The owner or operator of each vessel subject to...

  3. ExoMars 2016 arrives at Mars

    NASA Astrophysics Data System (ADS)

    Svedhem, Hakan; Vago, Jorge L.; ExoMars Team

    2016-10-01

    The Trace Gas Orbiter (TGO) and the Schiaparelli Entry, descent and landing Demonstrator Model (EDM) will arrive at Mars on 19 October 2016. The TGO and the EDM are part of the first step of the ExoMars Programme. They will be followed by a Rover and a long lived Surface Platform to be launched in 2020.The EDM is attached to the TGO for the full duration of the cruise to Mars and will be separated three days before arrival at Mars. After separation the TGO will perform a deflection manoeuvre and, on 19 October (during the EDM landing), enter into a highly elliptical near equatorial orbit. TGO will remain in this parking orbit until January 2017, when the orbital plane inclination will be changed to 74 degrees and aerobraking to the final 400 km near circular orbit will start. The final operational orbit is expected to be reached at the end of 2017.The TGO scientific payload consists of four instruments. These are: ACS and NOMAD, both infrared spectrometers for atmospheric measurements in solar occultation mode and in nadir mode, CASSIS, a multichannel camera with stereo imaging capability, and FREND, an epithermal neutron detector for search of subsurface hydrogen. The mass of the TGO is 3700 kg, including fuel. The EDM, with a mass of 600 kg, is mounted on top of the TGO as seen in its launch configuration. The main objective of the EDM is to demonstrate the capability of performing a safe entry, descent and landing on the surface, but it does carry a descent camera and a small battery powered meteorological package that may operate for a few days on the surface.The ExoMars programme is a joint activity by the European Space Agency(ESA) and ROSCOSMOS, Russia. ESA is providing the TGO spacecraft and Schiaparelli (EDM) and two of the TGO instruments and ROSCOSMOS is providing the launcher and the other two TGO instruments. After the arrival of the ExoMars 2020 mission at the surface of Mars, the TGO will handle the communication between the Earth and the Rover and

  4. An Outline of Data Aggregation Security in Heterogeneous Wireless Sensor Networks.

    PubMed

    Boubiche, Sabrina; Boubiche, Djallel Eddine; Bilami, Azzedine; Toral-Cruz, Homero

    2016-01-01

    Data aggregation processes aim to reduce the amount of exchanged data in wireless sensor networks and consequently minimize the packet overhead and optimize energy efficiency. Securing the data aggregation process is a real challenge since the aggregation nodes must access the relayed data to apply the aggregation functions. The data aggregation security problem has been widely addressed in classical homogeneous wireless sensor networks, however, most of the proposed security protocols cannot guarantee a high level of security since the sensor node resources are limited. Heterogeneous wireless sensor networks have recently emerged as a new wireless sensor network category which expands the sensor nodes' resources and capabilities. These new kinds of WSNs have opened new research opportunities where security represents a most attractive area. Indeed, robust and high security level algorithms can be used to secure the data aggregation at the heterogeneous aggregation nodes which is impossible in classical homogeneous WSNs. Contrary to the homogeneous sensor networks, the data aggregation security problem is still not sufficiently covered and the proposed data aggregation security protocols are numberless. To address this recent research area, this paper describes the data aggregation security problem in heterogeneous wireless sensor networks and surveys a few proposed security protocols. A classification and evaluation of the existing protocols is also introduced based on the adopted data aggregation security approach. PMID:27077866

  5. An Outline of Data Aggregation Security in Heterogeneous Wireless Sensor Networks

    PubMed Central

    Boubiche, Sabrina; Boubiche, Djallel Eddine; Bilami, Azzedine; Toral-Cruz, Homero

    2016-01-01

    Data aggregation processes aim to reduce the amount of exchanged data in wireless sensor networks and consequently minimize the packet overhead and optimize energy efficiency. Securing the data aggregation process is a real challenge since the aggregation nodes must access the relayed data to apply the aggregation functions. The data aggregation security problem has been widely addressed in classical homogeneous wireless sensor networks, however, most of the proposed security protocols cannot guarantee a high level of security since the sensor node resources are limited. Heterogeneous wireless sensor networks have recently emerged as a new wireless sensor network category which expands the sensor nodes’ resources and capabilities. These new kinds of WSNs have opened new research opportunities where security represents a most attractive area. Indeed, robust and high security level algorithms can be used to secure the data aggregation at the heterogeneous aggregation nodes which is impossible in classical homogeneous WSNs. Contrary to the homogeneous sensor networks, the data aggregation security problem is still not sufficiently covered and the proposed data aggregation security protocols are numberless. To address this recent research area, this paper describes the data aggregation security problem in heterogeneous wireless sensor networks and surveys a few proposed security protocols. A classification and evaluation of the existing protocols is also introduced based on the adopted data aggregation security approach. PMID:27077866

  6. An Outline of Data Aggregation Security in Heterogeneous Wireless Sensor Networks.

    PubMed

    Boubiche, Sabrina; Boubiche, Djallel Eddine; Bilami, Azzedine; Toral-Cruz, Homero

    2016-04-12

    Data aggregation processes aim to reduce the amount of exchanged data in wireless sensor networks and consequently minimize the packet overhead and optimize energy efficiency. Securing the data aggregation process is a real challenge since the aggregation nodes must access the relayed data to apply the aggregation functions. The data aggregation security problem has been widely addressed in classical homogeneous wireless sensor networks, however, most of the proposed security protocols cannot guarantee a high level of security since the sensor node resources are limited. Heterogeneous wireless sensor networks have recently emerged as a new wireless sensor network category which expands the sensor nodes' resources and capabilities. These new kinds of WSNs have opened new research opportunities where security represents a most attractive area. Indeed, robust and high security level algorithms can be used to secure the data aggregation at the heterogeneous aggregation nodes which is impossible in classical homogeneous WSNs. Contrary to the homogeneous sensor networks, the data aggregation security problem is still not sufficiently covered and the proposed data aggregation security protocols are numberless. To address this recent research area, this paper describes the data aggregation security problem in heterogeneous wireless sensor networks and surveys a few proposed security protocols. A classification and evaluation of the existing protocols is also introduced based on the adopted data aggregation security approach.

  7. NASA T-34C arrival at Dryden

    NASA Technical Reports Server (NTRS)

    1996-01-01

    A NASA T-34C aircraft, used for safety chase, is viewed by personnel on the ramp at the Dryden Flight Research Center, Edwards, California, after its arrival in June of 1996. The aircraft was previously used at the Lewis Research Center in propulsion experiments involving turboprop engines, and is now used as a chase aircraft at Dryden for smaller and slower research projects. Chase aircraft accompany research flights for photography and video purposes, and also as support for safety and research. The T-34 is used mainly for smaller remotely piloted vehicles which fly slower than NASA's F-18's, used for larger scale projects. The T-34C, built by Beech, carries a crew of 2 and is nicknamed the Mentor.

  8. The stratospheric arrival pair in infrasound propagation.

    PubMed

    Waxler, Roger; Evers, Läslo G; Assink, Jelle; Blom, Phillip

    2015-04-01

    The ideal case of a deep and well-formed stratospheric duct for long range infrasound propagation in the absence of tropospheric ducting is considered. A canonical form, that of a pair of arrivals, for ground returns of impulsive signals in a stratospheric duct is determined. The canonical form is derived from the geometrical acoustics approximation, and is validated and extended through full wave modeling. The full caustic structure of the field of ray paths is found and used to determine phase relations between the contributions to the wavetrain from different propagation paths. Finally, comparison with data collected from the 2005 fuel gas depot explosion in Buncefield, England is made. The correspondence between the theoretical results and the observations is shown to be quite good. PMID:25920837

  9. STS-79 astronauts arrive at SLF

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The STS-79 astronauts arrive at KSC's Shuttle Landing Facility at about the same time the three-day launch countdown gets under way. From left are Mission Specialists Carl E. Walz and John E. Blaha; Mission Commander William F. Readdy; Pilot Terrence W. Wilcutt; and Mission Specialists Thomas D. Akers and Jay Apt. Not too far away, final preparations are in work at Launch Pad 39A to prepare the Space Shuttle Atlantis for liftoff on the 79th Shuttle mission. During the approximately 10-day flight, Atlantis will dock with the Russian Space Station Mir and Blaha will transfer to the station. Returning with the STS-79 astronauts aboard Atlantis will be American astronaut Shannon Lucid, who is wrapping up a record-setting stay aboard Mir. Liftoff currently is set for Sept. 16 at about 4:54 a.m. EDT during an approximately seven-minute launch window.

  10. P-1 truss arrival at KSC

    NASA Technical Reports Server (NTRS)

    2000-01-01

    The P-1 truss, a component of the International Space Station, arrives inside the RLV hangar, located near the Shuttle Landing Facility at KSC. Approaching bad weather caused the detour as a precaution. The truss will eventually be transferred to the Operations and Checkout Building for processing. The P-1 truss, scheduled to fly in spring of 2002, is part of a total 10-truss, girder-like structure on the Station that will ultimately extend the length of a football field. Astronauts will attach the 14-by- 15 foot structure to the port side of the center truss, S0, during the spring assembly flight. The 33,000-pound P-1 will house the thermal radiator rotating joint (TRRJ) that will rotate the Station's radiators away from the sun to increase their maximum cooling efficiency.

  11. Determining surface wave arrival angle anomalies

    NASA Astrophysics Data System (ADS)

    Larson, Erik W. F.; Ekström, Göran

    2002-06-01

    A new method for measuring arrival angles of teleseismic Love and Rayleigh waves is developed. The new method utilizes estimates of surface wave dispersion to create a phase-matched filter to isolate the Love or Rayleigh wave in three-component recordings. The polarization of the filtered wave group is determined in the time domain by application of a variation of the complex polarization method of Vidale [1986]. Orientation, linearity, and ellipticity of particle motion are estimated in several frequency bands to determine the frequency-dependent polarization. The method employs an iterative scheme, by which a predicted Love wave, based on the estimated dispersion and polarization, is subtracted from the three-component data prior to the estimation of Rayleigh wave polarization, and vice versa. The method is applied to an extensive set of Global Seismographic Network data covering the years 1989-1998. Between 4244 and 15,075 measurements are collected for fundamental mode Love and Rayleigh waves at nine different periods (37 to 150 s). Measurement uncertainties are estimated using the statistics of observations for pairwise similar paths and are generally of the order of 15-50% of the total signal, depending on the period and the wave type. Large and azimuthally invariant angle anomalies are documented for several stations and are consistent with misorientation of the horizontal seismometers. Two schemes are employed to determine the misorientations: (1) an azimuthally weighted average at each station, and (2) a joint inversion for seismometer misorientation and globally heterogeneous phase velocities. The determined corrections are robust and correlate well with those reported in earlier studies. Azimuthally varying arrival angle anomalies are shown to agree qualitatively with predictions of wave refraction calculated for recent phase velocity maps, which explain up to 30% of the variance in the new measurements.

  12. Multi-echo processing by a bottlenose dolphin operating in "packet" transmission mode at long range.

    PubMed

    Finneran, James J; Schroth-Miller, Maddie; Borror, Nancy; Tormey, Megan; Brewer, Arial; Black, Amy; Bakhtiari, Kimberly; Goya, Gavin

    2014-11-01

    Bottlenose dolphins performing echolocation tasks at long ranges may utilize a transmission mode where bursts, or "packets," of echolocation clicks are emitted rather than single clicks. The clicks within each packet are separated by time intervals well below the two-way travel time, while the packets themselves are emitted at intervals greater than the two-way travel time. Packet use has been shown to increase with range; however, the exact function of packets and the advantages gained by their utilization remain unknown. In this study, the capability for dolphins to utilize multi-echo processing within packets of echoes was investigated by manipulating the number of available echoes within each packet as a dolphin performed a long-range echolocation task. The results showed an improvement in detectability with an increase in the number of echoes in each packet and suggest that packet use is an adaptation to allow multi-echo processing at long ranges without introducing range ambiguity.

  13. An effective packetization algorithm of LT codes for stable video streaming over wireless network

    NASA Astrophysics Data System (ADS)

    Lee, Dongju; Kim, Wan; Song, Hwangjun

    2011-09-01

    In this work, we propose an effective And-Or tree based packetization algorithm of Luby Transform (LT) codes to provide stable video streaming services by minimizing the deterioration of video streaming service quality caused by lost packets over error-prone wireless network. To accomplish our goal, the proposed packetization algorithm considers the relationships among encoded symbols of LT codes based on an And-Or tree analysis tool, and then puts the these encoded symbols into packets to minimize the packet loss effect during packet transmission and improve the decoding success rate of LT codes by reducing the correlations among packets. We conduct a mathematical analysis to prove performance of our packetization algorithm of LT codes compared with conventional packetization algorithm. Finally, the proposed system is fully implemented in Java and C/C++, and widely tested to show that the proposed packetization algorithm works reasonably well. The experimental results are provided to demonstrate that the proposed packetization algorithm supports more stable video streaming services with higher peak signal-to-nose ratio (PSNR) than the conventional packetization algorithm with various packet loss patterns, including random and burst packet loss patterns.

  14. A model of seismic coda arrivals to suppress spurious events.

    NASA Astrophysics Data System (ADS)

    Arora, N.; Russell, S.

    2012-04-01

    We describe a model of coda arrivals which has been added to NET-VISA (Network processing Vertically Integrated Seismic Analysis) our probabilistic generative model of seismic events, their transmission, and detection on a global seismic network. The scattered energy that follows a seismic phase arrival tends to deceive typical STA/LTA based arrival picking software into believing that a real seismic phase has been detected. These coda arrivals which tend to follow all seismic phases cause most network processing software including NET-VISA to believe that multiple events have taken place. It is not a simple matter of ignoring closely spaced arrivals since arrivals from multiple events can indeed overlap. The current practice in NET-VISA of pruning events within a small space-time neighborhood of a larger event works reasonably well, but it may mask real events produced in an after-shock sequence. Our new model allows any seismic arrival, even coda arrivals, to trigger a subsequent coda arrival. The probability of such a triggered arrival depends on the amplitude of the triggering arrival. Although real seismic phases are more likely to generate such coda arrivals. Real seismic phases also tend to generate coda arrivals with more strongly correlated parameters, for example azimuth and slowness. However, the SNR (Signal to Noise Ratio) of a coda arrival immediately following a phase arrival tends to be lower because of the nature of the SNR calculation. We have calibrated our model on historical statistics of such triggered arrivals and our inference accounts for them while searching for the best explanation of seismic events their association to the arrivals and the coda arrivals. We have tested our new model on one week of global seismic data spanning March 22, 2009 to March 29, 2009. Our model was trained on two and half months of data from April 5, 2009 to June 20, 2009. We use the LEB bulletin produced by the IDC (International Data Center) as the ground truth

  15. Rydberg wave packets and half-cycle electromagnetic pulses

    NASA Astrophysics Data System (ADS)

    Raman, Chandra Shekar

    1997-08-01

    This dissertation summarizes an examination of the dynamics of atomic Rydberg wave packets with coherent pulses of THz electromagnetic radiation consisting of less than a single cycle of the electric field. The bulk of the energy is contained in just a half-cycle. Previous work (1, 10) has shown how these half-cycle pulses can be used to ionize the highly excited states of an atom, and that a classical view of electronic motion in the atom explains the ionization mechanism. To further probe the boundary between classical trajectories and quantum mechanics, in this work we investigate dynamical combinations of Rydberg states, or Rydberg wave packets, and how they ionize under the influence of a half-cycle electromagnetic pulse. With time-domain techniques we are able to extract the dynamics of the wave packet from the ionization rate. We then observe wave packet motion in both the electronic radial and angular coordinates, and can view it directly with the half-cycle pulse anywhere on its trajectory. This is the unique feature of half- cycle pulse ionization. Semiclassical ideas of ionization in conjunction with quantum descriptions of the wave packet, are capable of reproducing the main trends in our data, and in the absence of a rigorous model we rely on these. Experiments of this nature provide examples of the ongoing effort to use the coherent properties of radiation to control electronic motion in an atom, as well as to probe the boundaries between quantum and classical mechanics.

  16. Integrated optical buffers for packet-switched networks

    NASA Astrophysics Data System (ADS)

    Burmeister, Emily Frances

    Routers form the backbone of the Internet, directing data to the right locations with huge throughput capacity of terabits/second) and very few errors (1 error allowed in 1012 bits). However, as the Internet continues to grow rapidly, so must the capacity of electronic routers, thereby also growing in footprint and power consumption. The energy bill alone has developers looking for an alternate solution. Today's routers can only operate with electrical signals although Internet data is transmitted optically. This requires the data to be converted from the optical domain to the electrical domain and back again. Optical routers have the potential of saving in power by omitting these conversions, but have been held back in part by the lack of a practical optical memory device. This work presents the first integrated optical buffer for next generation optical packet-switched networks. Buffering is required in a router to move packets of data in order to avoid collisions between packets heading to the same destination at the same time. The device presented here uses an InP-based two-by-two switch with a silica waveguide delay to form a recirculating buffer. Packet storage was shown with 98% packet recovery for 5 circulations. Autonomous contention resolution was demonstrated with two buffered channels to show that the technology is a realistic solution for creating multiple element buffers on multiple router ports. This thesis proposes and demonstrates the first integrated optical random access memory, thereby making a great stride toward high capacity optical routers.

  17. Aggregations in Flatworms.

    ERIC Educational Resources Information Center

    Liffen, C. L.; Hunter, M.

    1980-01-01

    Described is a school project to investigate aggregations in flatworms which may be influenced by light intensity, temperature, and some form of chemical stimulus released by already aggregating flatworms. Such investigations could be adopted to suit many educational levels of science laboratory activities. (DS)

  18. A New Reactive FMIPv6 Mechanism for Minimizing Packet Loss

    NASA Astrophysics Data System (ADS)

    Kim, Pyungsoo

    This paper considers a new reactive fast handover MIPv6 (FMIPv6) mechanism to minimize packet loss of the existing mechanism. The primary idea of the proposed reactive FMIPv6 mechanism is that the serving access router buffers packets toward the mobile node (MN) as soon as the link layer between MN and serving base station is disconnected. To implement the proposed mechanism, the router discovery message exchanged between MN and serving access router is extended. In addition, the IEEE 802.21 Media Independent Handover Function event service message is defined newly. Through analytic performance evaluation and experiments, the proposed reactive FMIPv6 mechanism can be shown to minimize packet loss much than the existing mechanism.

  19. Semiclassical Dynamics of Electron Wave Packet States with Phase Vortices

    SciTech Connect

    Bliokh, Konstantin Yu.; Bliokh, Yury P.; Savel'ev, Sergey; Nori, Franco

    2007-11-09

    We consider semiclassical higher-order wave packet solutions of the Schroedinger equation with phase vortices. The vortex line is aligned with the propagation direction, and the wave packet carries a well-defined orbital angular momentum (OAM) ({Dirac_h}/2{pi})l (l is the vortex strength) along its main linear momentum. The probability current coils around the momentum in such OAM states of electrons. In an electric field, these states evolve like massless particles with spin l. The magnetic-monopole Berry curvature appears in momentum space, which results in a spin-orbit-type interaction and a Berry/Magnus transverse force acting on the wave packet. This brings about the OAM Hall effect. In a magnetic field, there is a Zeeman interaction, which, can lead to more complicated dynamics.

  20. On-board congestion control for satellite packet switching networks

    NASA Technical Reports Server (NTRS)

    Chu, Pong P.

    1991-01-01

    It is desirable to incorporate packet switching capability on-board for future communication satellites. Because of the statistical nature of packet communication, incoming traffic fluctuates and may cause congestion. Thus, it is necessary to incorporate a congestion control mechanism as part of the on-board processing to smooth and regulate the bursty traffic. Although there are extensive studies on congestion control for both baseband and broadband terrestrial networks, these schemes are not feasible for space based switching networks because of the unique characteristics of satellite link. Here, we propose a new congestion control method for on-board satellite packet switching. This scheme takes into consideration the long propagation delay in satellite link and takes advantage of the the satellite's broadcasting capability. It divides the control between the ground terminals and satellite, but distributes the primary responsibility to ground terminals and only requires minimal hardware resource on-board satellite.

  1. Bufferless Ultra-High Speed All-Optical Packet Routing

    NASA Astrophysics Data System (ADS)

    Muttagi, Shrihari; Prince, Shanthi

    2011-10-01

    All-Optical network is still in adolescence to cope up with steep rise in data traffic at the backbone network. Routing of packets in optical network depends on the processing speed of the All-Optical routers, thus there is a need to enhance optical processing to curb the delay in packet forwarding unit. In the proposed scheme, the header processing takes place on fly, therefore processing delay is at its lower limit. The objective is to propose a framework which establishes high data rate transmission with least latency in data routing from source to destination. The Routing table and optical header pulses are converted into Pulse Position (PP) format, thus reducing the complexity and in turn the processing delay. Optical pulse matching is exercised which results in multi-output transmission. This results in ultra-high speed packet forwarding unit. In addition, this proposed scheme includes dispersion compensation unit, which makes the data reliable.

  2. Chiral wave-packet scattering in Weyl semimetals

    NASA Astrophysics Data System (ADS)

    Jiang, Qing-Dong; Jiang, Hua; Liu, Haiwen; Sun, Qing-Feng; Xie, X. C.

    2016-05-01

    In quantum mechanics, a particle is best described by the wave packet instead of the plane wave. Here, we study the wave-packet scattering problem in Weyl semimetals with the low-energy Weyl fermions of different chiralities. Our results show that the wave packet acquires a chirality-protected shift in the single-impurity scattering process. More importantly, the chirality-protected shift can lead to an anomalous scattering probability, and thus affects the transport properties in Weyl semimetals. We find that the ratio between the transport lifetime and the quantum lifetime increases sharply when the Fermi energy approaches the Weyl nodes, providing an explanation of the experimentally observed ultrahigh mobility in topological (Weyl or Dirac) semimetals.

  3. Confined quantum time of arrival for the vanishing potential

    SciTech Connect

    Galapon, Eric A.; Caballar, Roland F.; Bahague, Ricardo

    2005-12-15

    We give full account of our recent report in E. A. Galapon, R. Caballar, and R. Bahague, Phys. Rev. Lett. 93, 180406 (2004), where it is shown that formulating the free quantum time of arrival problem in a segment of the real line suggests rephrasing the quantum time of arrival problem to finding a complete set of states that evolve to unitarily arrive at a given point at a definite time. For a spatially confined particle, here it is shown explicitly that the problem admits a solution in the form of an eigenvalue problem of a class of compact and self-adjoint time of arrival operators derived by a quantization of the classical time of arrival. The eigenfunctions of these operators are numerically demonstrated to unitarily arrive at the origin at their respective eigenvalues.

  4. Emergency contraception use up -- new ECP arrives.

    PubMed

    1999-09-01

    The first progestin-only dedicated emergency contraceptive pill (ECP) is about to enter the US market. The arrival of Plan B, a levonorgestrel-only ECP produced by the Women's Capital Corporation (WCC) of Seattle, has been long awaited by providers in the US because of it is more effective and produces fewer side effects than does the combined regimen. The WCC is taking a different marketing and distributing approach to emergency contraception than its competitor, Gynetics, focusing on existing ECP provider/dispensers such as Planned Parenthood affiliates, major Title X programs, and college/university student health centers. The FDA has also approved a change in product labeling for Gynetics¿ ECU Preven. The change, marked by the disappearance of the "Black Box Warning," puts the benefits and risks of emergency contraception in perspective, according to a Gynetics executive. It further eliminates substantial restrictions on the company's ability to communicate directly to the consumer and to the medical professional. The FDA¿s decisions should help to accelerate the process of building awareness of emergency contraception and its availability in the US.

  5. Cassini-Huygens arrives at Saturn

    NASA Astrophysics Data System (ADS)

    McGee, H. W.

    2004-08-01

    Cover images: Following a seven-year journey through the solar system, the NASA spacecraft Cassini, carrying the ESA Titan probe Huygens, arrived at Saturn on 2004 July 1. With a flawlessly executed manoeuvre and 95-minute engine burn the spacecraft passed twice through Saturn's rings and took up orbit around the planet, ready for its four-year mission to study the Saturnian system. The cover shows Saturn's atmosphere and rings, imaged on 2004 May 15 from a distance of 24.7 million km; and three closeup images recorded during the ring plane crossing. Clockwise from right: density waves and unexpected detail in the A ring, exquisitely delicate patterning in the F ring, and the Cassini Division, seen from the unlit side of the rings. The image on the right shows a wide view of the F ring. NASA/JPL/Space Science Institute. [Hazel McGee and Nick James represented the BAA at JPL during this historic event, and will report further in future issues of the Journal.

  6. Wave packet propagation across barriers by semiclassical initial value methods

    NASA Astrophysics Data System (ADS)

    Petersen, Jakob; Kay, Kenneth G.

    2015-07-01

    Semiclassical initial value representation (IVR) formulas for the propagator have difficulty describing tunneling through barriers. A key reason is that these formulas do not automatically reduce, in the classical limit, to the version of the Van Vleck-Gutzwiller (VVG) propagator required to treat barrier tunneling, which involves trajectories that have complex initial conditions and that follow paths in complex time. In this work, a simple IVR expression, that has the correct tunneling form in the classical limit, is derived for the propagator in the case of one-dimensional barrier transmission. Similarly, an IVR formula, that reduces to the Generalized Gaussian Wave Packet Dynamics (GGWPD) expression [D. Huber, E. J. Heller, and R. Littlejohn, J. Chem. Phys. 89, 2003 (1988)] in the classical limit, is derived for the transmitted wave packet. Uniform semiclassical versions of the IVR formulas are presented and simplified expressions in terms of real trajectories and WKB penetration factors are described. Numerical tests show that the uniform IVR treatment gives good results for wave packet transmission through the Eckart and Gaussian barriers in all cases examined. In contrast, even when applied with the proper complex trajectories, the VVG and GGWPD treatments are inaccurate when the mean energy of the wave packet is near the classical transmission threshold. The IVR expressions for the propagator and wave packet are cast as contour integrals in the complex space of initial conditions and these are generalized to potentially allow treatment of a larger variety of systems. A steepest descent analysis of the contour integral formula for the wave packet in the present cases confirms its relationship to the GGWPD method, verifies its semiclassical validity, and explains results of numerical calculations.

  7. Advances in integrated photonic circuits for packet-switched interconnection

    NASA Astrophysics Data System (ADS)

    Williams, Kevin A.; Stabile, Ripalta

    2014-03-01

    Sustained increases in capacity and connectivity are needed to overcome congestion in a range of broadband communication network nodes. Packet routing and switching in the electronic domain are leading to unsustainable energy- and bandwidth-densities, motivating research into hybrid solutions: optical switching engines are introduced for massive-bandwidth data transport while the electronic domain is clocked at more modest GHz rates to manage routing. Commercially-deployed optical switching engines using MEMS technologies are unwieldy and too slow to reconfigure for future packet-based networking. Optoelectronic packet-compliant switch technologies have been demonstrated as laboratory prototypes, but they have so far mostly used discretely pigtailed components, which are impractical for control plane development and product assembly. Integrated photonics has long held the promise of reduced hardware complexity and may be the critical step towards packet-compliant optical switching engines. Recently a number of laboratories world-wide have prototyped optical switching circuits using monolithic integration technology with up to several hundreds of integrated optical components per chip. Our own work has focused on multi-input to multi-output switching matrices. Recently we have demonstrated 8×8×8λ space and wavelength selective switches using gated cyclic routers and 16×16 broadband switching chips using monolithic multi-stage networks. We now operate these advanced circuits with custom control planes implemented with FPGAs to explore real time packet routing in multi-wavelength, multi-port test-beds. We review our contributions in the context of state of the art photonic integrated circuit technology and packet optical switching hardware demonstrations.

  8. The Open Host Network Packet Process Correlator for Windows

    2014-06-17

    The Hone sensors are packet-process correlation engines that log the relationships between applications and the communications they are responsible for. Hone sensors are available for a variety of platforms including Linux, Windows, and MacOSX. Hone sensors are designed to help analysts understand the meaning of communications on a deeper level by associating the origin or destination process to the communication. They do this by tracing communications on a per-packet basis, through the kernel of themore » operating system to determine their ultimate source/destination on the monitored machine.« less

  9. Wave packet dynamics under effect of a pulsed electric field

    NASA Astrophysics Data System (ADS)

    da Silva, A. R. C. B.; de Moura, F. A. B. F.; Dias, W. S.

    2016-06-01

    We studied the dynamics of an electron in a crystalline one-dimensional model under effect of a time-dependent Gaussian field. The time evolution of an initially Gaussian wave packet it was obtained through the numerical solution of the time-dependent Schrödinger equation. Our analysis consists of computing the electronic centroid as well as the mean square displacement. We observe that the electrical pulse is able to promote a special kind of displacement along the chain. We demonstrated a direct relation between the group velocity of the wave packet and the applied electrical pulses. We compare those numerical calculations with a semi-classical approach.

  10. The Open Host Network Packet Process Correlator for Windows

    SciTech Connect

    2014-06-17

    The Hone sensors are packet-process correlation engines that log the relationships between applications and the communications they are responsible for. Hone sensors are available for a variety of platforms including Linux, Windows, and MacOSX. Hone sensors are designed to help analysts understand the meaning of communications on a deeper level by associating the origin or destination process to the communication. They do this by tracing communications on a per-packet basis, through the kernel of the operating system to determine their ultimate source/destination on the monitored machine.

  11. Control with a random access protocol and packet dropouts

    NASA Astrophysics Data System (ADS)

    Wang, Liyuan; Guo, Ge

    2016-08-01

    This paper investigates networked control systems whose actuators communicate with the controller via a limited number of unreliable channels. The access to the channels is decided by a so-called group random access protocol, which is modelled as a binary Markov sequence. Data packet dropouts in the channels are modelled as independent Bernoulli processes. For such systems, a systematic characterisation for controller synthesis is established and stated in terms of the transition probabilities of the Markov protocol and the packet dropout probabilities. The results are illustrated via a numerical example.

  12. Gabor Wave Packet Method to Solve Plasma Wave Equations

    SciTech Connect

    A. Pletzer; C.K. Phillips; D.N. Smithe

    2003-06-18

    A numerical method for solving plasma wave equations arising in the context of mode conversion between the fast magnetosonic and the slow (e.g ion Bernstein) wave is presented. The numerical algorithm relies on the expansion of the solution in Gaussian wave packets known as Gabor functions, which have good resolution properties in both real and Fourier space. The wave packets are ideally suited to capture both the large and small wavelength features that characterize mode conversion problems. The accuracy of the scheme is compared with a standard finite element approach.

  13. Symmetry and conservation laws in semiclassical wave packet dynamics

    SciTech Connect

    Ohsawa, Tomoki

    2015-03-15

    We formulate symmetries in semiclassical Gaussian wave packet dynamics and find the corresponding conserved quantities, particularly the semiclassical angular momentum, via Noether’s theorem. We consider two slightly different formulations of Gaussian wave packet dynamics; one is based on earlier works of Heller and Hagedorn and the other based on the symplectic-geometric approach by Lubich and others. In either case, we reveal the symplectic and Hamiltonian nature of the dynamics and formulate natural symmetry group actions in the setting to derive the corresponding conserved quantities (momentum maps). The semiclassical angular momentum inherits the essential properties of the classical angular momentum as well as naturally corresponds to the quantum picture.

  14. Zeno dynamics in wave-packet diffraction spreading

    SciTech Connect

    Porras, Miguel A.; Luis, Alfredo; Gonzalo, Isabel; Sanz, Angel S.

    2011-11-15

    We analyze a simple and feasible practical scheme displaying Zeno, anti-Zeno, and inverse-Zeno effects in the observation of wave-packet spreading caused by free evolution. The scheme is valid both in spatial diffraction of classical optical waves and in time diffraction of a quantum wave packet. In the optical realization, diffraction spreading is observed by placing slits between a light source and a light-power detector. We show that the occurrence of Zeno or anti-Zeno effects depends just on the frequency of observations between the source and detector. These effects are seen to be related to the diffraction mode theory in Fabry-Perot resonators.

  15. Short-time Chebyshev wave packet method for molecular photoionization

    NASA Astrophysics Data System (ADS)

    Sun, Zhaopeng; Zheng, Yujun

    2016-08-01

    In this letter we present the extended usage of short-time Chebyshev wave packet method in the laser induced molecular photoionization dynamics. In our extension, the polynomial expansion of the exponential in the time evolution operator, the Hamiltonian operator can act on the wave packet directly which neatly avoids the matrix diagonalization. This propagation scheme is of obvious advantages when the dynamical system has large Hamiltonian matrix. Computational simulations are performed for the calculation of photoelectronic distributions from intense short pulse ionization of K2 and NaI which represent the Born-Oppenheimer (BO) model and Non-BO one, respectively.

  16. RATE-ADJUSTMENT ALGORITHM FOR AGGREGATE TCP CONGESTION CONTROL

    SciTech Connect

    P. TINNAKORNSRISUPHAP, ET AL

    2000-09-01

    The TCP congestion-control mechanism is an algorithm designed to probe the available bandwidth of the network path that TCP packets traverse. However, it is well-known that the TCP congestion-control mechanism does not perform well on networks with a large bandwidth-delay product due to the slow dynamics in adapting its congestion window, especially for short-lived flows. One promising solution to the problem is to aggregate and share the path information among TCP connections that traverse the same bottleneck path, i.e., Aggregate TCP. However, this paper shows via a queueing analysis of a generalized processor-sharing (GPS) queue with regularly-varying service time that a simple aggregation of local TCP connections together into a single aggregate TCP connection can result in a severe performance degradation. To prevent such a degradation, we introduce a rate-adjustment algorithm. Our simulation confirms that by utilizing our rate-adjustment algorithm on aggregate TCP, connections which would normally receive poor service achieve significant performance improvements without penalizing connections which already receive good service.

  17. Emerging leaders 1991. Six who have arrived.

    PubMed

    Weber, D O

    1991-01-01

    "I would quibble with the idea that Cheryl is an 'emerging leader,"' observes a colleague of one of this year's honorees. "I believe she has arrived." In truth, each of the six extraordinary people cited as 1991's Emerging Leaders have had a major impact on their organizations and, by example and design, on the nature and quality of healthcare in their communities. But then, the annual call for nominations demands nothing less. Sponsors Korn/Ferry International and The Healthcare Forum are "looking for...talented people with the proven ability to nurture the growth of the industry. They are dynamic, decisive young leaders who have already made a mark." Five men and one woman, all age 40 or younger, were selected as this year's Emerging Leaders in two separate categories. Three represent large healthcare organizations, three smaller urban or rural institutions--generally hospitals with fewer than 200 beds. Interestingly, nearly all were influenced to pursue careers in healthcare at an early age. Two had physician parents, two were sons of healthcare administrators, two worked in hospitals as teenagers. All, of course, have shown their mettle in difficult times and complex, uncomfortable situations. All have been pivotal in turning around failing--or at least beleaguered--organizations. Yet, while each has labored diligently to further the interests of his or her own organization and constituency, each has also sought to shape a more cooperative system. As honoree Larry Sanders observes, "Competition without conscience will deny our claim to a true community leadership role." Marveling at the accomplishments of honoree Kevin Fickenscher, an awed peer declared: "One of these days we'll all be working for him!"(ABSTRACT TRUNCATED AT 250 WORDS) PMID:10160736

  18. Aggregate and the environment

    USGS Publications Warehouse

    Langer, William H.; Drew, Lawrence J.; Sachs, J.S.

    2004-01-01

    This book is designed to help you understand our aggregate resources-their importance, where they come from, how they are processed for our use, the environmental concerns related to their mining and processing, how those concerns are addressed, and the policies and regulations designed to safeguard workers, neighbors, and the environment from the negative impacts of aggregate mining. We hope this understanding will help prepare you to be involved in decisions that need to be made-individually and as a society-to be good stewards of our aggregate resources and our living planet.

  19. Joint source coding, transport processing, and error concealment for H.323-based packet video

    NASA Astrophysics Data System (ADS)

    Zhu, Qin-Fan; Kerofsky, Louis

    1998-12-01

    In this paper, we investigate how to adapt different parameters in H.263 source coding, transport processing and error concealment to optimize end-to-end video quality at different bitrates and packet loss rates for H.323-based packet video. First different intra coding patterns are compared and we show that the contiguous rectangle or square block pattern offers the best performance in terms of video quality in the presence of packet loss. Second, the optimal intra coding frequency is found for different bitrates and packet loss rates. The optimal number of GOB headers to be inserted in the source coding is then determined. The effect of transport processing strategies such as packetization and retransmission is also examined. For packetization, the impact of packet size and the effect of macroblock segmentation to picture quality are investigated. Finally, we show that the dejitter buffering delay can be used to the advantage for packet loss recovery with video retransmission without incurring any extra delay.

  20. A multi-ring optical packet and circuit integrated network with optical buffering.

    PubMed

    Furukawa, Hideaki; Shinada, Satoshi; Miyazawa, Takaya; Harai, Hiroaki; Kawasaki, Wataru; Saito, Tatsuhiko; Matsunaga, Koji; Toyozumi, Tatuya; Wada, Naoya

    2012-12-17

    We newly developed a 3 × 3 integrated optical packet and circuit switch-node. Optical buffers and burst-mode erbium-doped fiber amplifiers with the gain flatness are installed in the 3 × 3 switch-node. The optical buffer can prevent packet collisions and decrease packet loss. We constructed a multi-ring optical packet and circuit integrated network testbed connecting two single-ring networks and a client network by the 3 × 3 switch-node. For the first time, we demonstrated 244 km fiber transmission and 5-node hopping of multiplexed 14-wavelength 10 Gbps optical paths and 100 Gbps optical packets encapsulating 10 Gigabit Ethernet frames on the testbed. Error-free (frame error rate < 1 × 10(-4)) operation was achieved with optical packets of various packet lengths. In addition, successful avoidance of packet collisions by optical buffers was confirmed.

  1. Information Theory Filters for Wavelet Packet Coefficient Selection with Application to Corrosion Type Identification from Acoustic Emission Signals

    PubMed Central

    Van Dijck, Gert; Van Hulle, Marc M.

    2011-01-01

    The damage caused by corrosion in chemical process installations can lead to unexpected plant shutdowns and the leakage of potentially toxic chemicals into the environment. When subjected to corrosion, structural changes in the material occur, leading to energy releases as acoustic waves. This acoustic activity can in turn be used for corrosion monitoring, and even for predicting the type of corrosion. Here we apply wavelet packet decomposition to extract features from acoustic emission signals. We then use the extracted wavelet packet coefficients for distinguishing between the most important types of corrosion processes in the chemical process industry: uniform corrosion, pitting and stress corrosion cracking. The local discriminant basis selection algorithm can be considered as a standard for the selection of the most discriminative wavelet coefficients. However, it does not take the statistical dependencies between wavelet coefficients into account. We show that, when these dependencies are ignored, a lower accuracy is obtained in predicting the corrosion type. We compare several mutual information filters to take these dependencies into account in order to arrive at a more accurate prediction. PMID:22163921

  2. Standard services for the capture, processing, and distribution of packetized telemetry data

    NASA Technical Reports Server (NTRS)

    Stallings, William H.

    1989-01-01

    Standard functional services for the capture, processing, and distribution of packetized data are discussed with particular reference to the future implementation of packet processing systems, such as those for the Space Station Freedom. The major functions are listed under the following major categories: input processing, packet processing, and output processing. A functional block diagram of a packet data processing facility is presented, showing the distribution of the various processing functions as well as the primary data flow through the facility.

  3. Protein Colloidal Aggregation Project

    NASA Technical Reports Server (NTRS)

    Oliva-Buisson, Yvette J. (Compiler)

    2014-01-01

    To investigate the pathways and kinetics of protein aggregation to allow accurate predictive modeling of the process and evaluation of potential inhibitors to prevalent diseases including cataract formation, chronic traumatic encephalopathy, Alzheimer's Disease, Parkinson's Disease and others.

  4. Compression of echocardiographic scan line data using wavelet packet transform

    NASA Technical Reports Server (NTRS)

    Hang, X.; Greenberg, N. L.; Qin, J.; Thomas, J. D.

    2001-01-01

    An efficient compression strategy is indispensable for digital echocardiography. Previous work has suggested improved results utilizing wavelet transforms in the compression of 2D echocardiographic images. Set partitioning in hierarchical trees (SPIHT) was modified to compress echocardiographic scanline data based on the wavelet packet transform. A compression ratio of at least 94:1 resulted in preserved image quality.

  5. A CURRICULUM FOR ENGLISH, STUDENT PACKET, GRADE 12.

    ERIC Educational Resources Information Center

    Nebraska Univ., Lincoln. Curriculum Development Center.

    THE LITERATURE PROGRAM OF THE GRADE 12 STUDENT PACKET OF THE NEBRASKA ENGLISH CURRICULUM CONSISTS OF A SELECTIVE SURVEY OF ENGLISH LITERATURE FROM THE RENAISSANCE TO THE 20TH CENTURY. IT BEGINS WITH A UNIT ON SHAKESPEAREAN TRAGEDY IN WHICH STUDENTS READ REVENGE TRAGEDIES--SENECA'S "THYESTES" AND KYD'S "THE SPANISH TRAGEDY"--AS PREPARATION FOR THE…

  6. Scattering of wave packets on atoms in the Born approximation

    NASA Astrophysics Data System (ADS)

    Karlovets, D. V.; Kotkin, G. L.; Serbo, V. G.

    2015-11-01

    It has recently been demonstrated experimentally that 200 -300 keV electrons with the unusual spatial profiles can be produced and even focused to a subnanometer scale—namely, electrons carrying nonzero orbital angular momentum and also the so-called Airy beams. Since the wave functions of such electrons do not represent plane waves, the standard Born formula for scattering of them off a potential field is no longer applicable and, hence, needs modification. In the present paper, we address the generic problem of elastic scattering of a wave packet of a fast nonrelativistic particle off a potential field. We obtain simple and convenient formulas for a number of events and an effective cross section in such a scattering, which represent generalization of the Born formula for a case when finite sizes and spatial inhomogeneity of the initial packet should be taken into account. As a benchmark, we consider two simple models corresponding to scattering of a Gaussian wave packet on a Gaussian potential and on a hydrogen atom, and perform a detailed analysis of the effects brought about by the limited sizes of the incident beam and by the finite impact parameter between the potential center and the packet's axis.

  7. Energy Crisis: Libya's and Nigeria's Role. Resource Packet.

    ERIC Educational Resources Information Center

    African-American Inst., New York, NY. School Services Div.

    This resource packet contains practical suggestions and resource materials to help secondary teachers teach about Libya's and Nigeria's roles in the energy crisis. Students become acquainted with the governments and cultures of the two countries, examine their social problems, and learn how the Libyan and Nigerian governments are using money from…

  8. Teaching about the U.S. Constitution. A Resource Packet.

    ERIC Educational Resources Information Center

    Leming, Robert S.; And Others

    The 200th anniversary of the United States Constitution offers an excellent opportunity for encouraging renewed study of the principles and foundations of constitutional government. This resource packet provides a listing of current materials and resources to aid teachers in planning lesson units. The listings include: (1) professional…

  9. Solar Energy Education Packet for Elementary & Secondary Students.

    ERIC Educational Resources Information Center

    Center for Renewable Resources, Washington, DC.

    The arrangement of this packet is essentially evolutionary, with a conscious effort to alternate reading assignments, activities and experiments. It begins with solar energy facts and terminology as background to introduce the reader to basic concepts. It progresses into a discussion of passive solar systems. This is followed by several projects…

  10. 41 CFR 101-39.306 - Operator's packet.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Regulations System FEDERAL PROPERTY MANAGEMENT REGULATIONS AVIATION, TRANSPORTATION, AND MOTOR VEHICLES 39-INTERAGENCY FLEET MANAGEMENT SYSTEMS 39.3-Use and Care of GSA Interagency Fleet Management System Vehicles § 101-39.306 Operator's packet. The GSA Interagency Fleet Management System (IFMS) will provide...

  11. 41 CFR 101-39.306 - Operator's packet.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Regulations System FEDERAL PROPERTY MANAGEMENT REGULATIONS AVIATION, TRANSPORTATION, AND MOTOR VEHICLES 39-INTERAGENCY FLEET MANAGEMENT SYSTEMS 39.3-Use and Care of GSA Interagency Fleet Management System Vehicles § 101-39.306 Operator's packet. The GSA Interagency Fleet Management System (IFMS) will provide...

  12. Using the Internet To Create Primary Source Teaching Packets.

    ERIC Educational Resources Information Center

    VanFossen, Phillip J.; Shiveley, James M.

    2000-01-01

    Describes strategies and guidelines for creating age- and content-appropriate primary source documents using the Internet. Discusses the value of using topic-specific primary source teaching packets, or jackdaws. Provides three Internet generated jackdaws: New Deal/FDR, Home Front during World War II, and the Gilded Age. Addresses fair use issues.…

  13. An Efficient Conflict Detection Algorithm for Packet Filters

    NASA Astrophysics Data System (ADS)

    Lee, Chun-Liang; Lin, Guan-Yu; Chen, Yaw-Chung

    Packet classification is essential for supporting advanced network services such as firewalls, quality-of-service (QoS), virtual private networks (VPN), and policy-based routing. The rules that routers use to classify packets are called packet filters. If two or more filters overlap, a conflict occurs and leads to ambiguity in packet classification. This study proposes an algorithm that can efficiently detect and resolve filter conflicts using tuple based search. The time complexity of the proposed algorithm is O(nW+s), and the space complexity is O(nW), where n is the number of filters, W is the number of bits in a header field, and s is the number of conflicts. This study uses the synthetic filter databases generated by ClassBench to evaluate the proposed algorithm. Simulation results show that the proposed algorithm can achieve better performance than existing conflict detection algorithms both in time and space, particularly for databases with large numbers of conflicts.

  14. Using Document Reading Activity Packets (DRAP) in the Classroom.

    ERIC Educational Resources Information Center

    Adomanis, James F.; Schulz, Constance

    1987-01-01

    Reviews a Document Reading Activity Packet (DRAP) revolving around the "Fort Washington Incident" of the War of 1812 and the resulting court martial of Captain Samuel T. Dyson. Explains this exercise is designed to stimulate students' interest in their own state histories as well as stimulate their curiosity for further research. (BSR)

  15. Office Reprographics. Instructor's Guide. Student Activity Packet. Office Occupations.

    ERIC Educational Resources Information Center

    Johnson, Diane E.

    This training package, one in a series of instructional modules consisting of an instructor's guide and a student activity packet, deals with office reprographics. Included in the instructor's guide are general directions for implementing the presentation; a detailed guide for teaching the lesson that includes performance objectives, suggestions…

  16. A CURRICULUM FOR ENGLISH, STUDENT PACKET, GRADE 7.

    ERIC Educational Resources Information Center

    Nebraska Univ., Lincoln. Curriculum Development Center.

    THE SEVENTH-GRADE STUDENT PACKET, PRODUCED BY THE NEBRASKA CURRICULUM DEVELOPMENT CENTER, BEGINS WITH THE UNIT ENTITLED "THE MAKING OF STORIES" IN WHICH STUDENTS CONSIDER WRITERS' AUDIENCES AND METHODS OF COMPOSITION AND PRESENTATION. SUCH MATERIAL AS "A CHRISTMAS CAROL" AND SELECTIONS FROM "THE ODYSSEY,""BEOWULF,""HYMN TO HERMES," AND GRIMM'S…

  17. Marine and Coastal Resources. Global Issues Education Packet.

    ERIC Educational Resources Information Center

    Holm, Amy E.

    At least 70% of the Earth is covered with water. This packet provides background information on eight areas of concern regarding marine and coastal resources. Considered are: (1) "Coastal Resources"; (2) "Mangroves"; (3) "Coral Reefs"; (4) "Ocean Resources"; (5) "Aquaculture"; (6) "Pollution"; (7) "Marine Debris"; and (8) "The Global Commons."…

  18. Teen Pregnancy Prevention and Support. An Introductory Packet.

    ERIC Educational Resources Information Center

    California Univ., Los Angeles. Center for Mental Health Schools.

    This introductory packet is designed to help those with an interest in preventing teen pregnancy. It opens with "A Brief Introduction to Teen Pregnancy Prevention and Support," an essay by the Center for Mental Health in Schools of the University of California, Los Angeles, that outlines the dimensions of the problem. "A Quick Overview of Some…

  19. Hardware packet pacing using a DMA in a parallel computer

    DOEpatents

    Chen, Dong; Heidelberger, Phillip; Vranas, Pavlos

    2013-08-13

    Method and system for hardware packet pacing using a direct memory access controller in a parallel computer which, in one aspect, keeps track of a total number of bytes put on the network as a result of a remote get operation, using a hardware token counter.

  20. "Macbeth." A Play Packet To Accompany "Elementary, My Dear Shakespeare."

    ERIC Educational Resources Information Center

    Engen, Barbara; Campbell, Joy

    Intended for use by elementary school teachers as a supplement to the book, "Elementary, My Dear Shakespeare," or for use by itself to produce one Shakespeare play, this play packet contains ready-to-reproduce materials for the production of "Macbeth." Materials include: staging suggestions for scenery, props, lighting, and costumes; a short…

  1. Environmental Education Inservice Training Packet for the Intermediate Level.

    ERIC Educational Resources Information Center

    Upper Mississippi River ECO-Center, Thomson, IL.

    The inservice teacher training packet, developed with help from the environmental education program of the Upper Mississippi River ECO-Center, is designed to help intermediate-level teachers develop teaching skills which will enable them to introduce environmental or outdoor education to their students and develop those concepts, attitudes, and…

  2. Maintaining Inequality: A Background Packet on Tracking and Ability Grouping.

    ERIC Educational Resources Information Center

    National Coalition of Education Activists, Rosendale, NY.

    This document includes a selection of materials from the National Coalition of Education Activists (NCEA) on tracking and ability grouping designed to be a tool for teachers who wish to organize their school or district against tracking. The packet contains a cover letter, a response/feedback form, and reproductions of the following articles: (1)…

  3. A CURRICULUM FOR ENGLISH, TEACHER PACKET, GRADE 11.

    ERIC Educational Resources Information Center

    Nebraska Univ., Lincoln. Curriculum Development Center.

    UNITS IN THE TEACHER PACKET FOR THE 11TH-GRADE NEBRASKA ENGLISH CURRICULUM ARE ORGANIZED AROUND THREE MAJOR THEMES IN AMERICAN LITERATURE--MAN AND NATURE, MAN AND MORAL LAW, AND MAN AND SOCIETY. THE MAN AND NATURE THEME IS EXAMINED IN TWO UNITS--"INDIVIDUALISM AND IDEALISM, SPIRITUAL AUTOBIOGRAPHY" AND "THE SEARCH FOR FORM." THE FORMER UNIT, AN…

  4. Wave packet motion in harmonic potential and computer visualization

    NASA Technical Reports Server (NTRS)

    Tsuru, Hideo; Kobayashi, Takeshi

    1993-01-01

    Wave packet motions of a single electron in harmonic potentials or a magnetic field are obtained analytically. The phase of the wave function which depends on both time and space is also presented explicitly. The probability density of the electron changes its width and central position periodically. These results are visualized using computer animation techniques.

  5. Quality Enhancement of Packet Audio with Time-Scale Modification

    NASA Astrophysics Data System (ADS)

    Liu, Fang; Kuo, C.-C. Jay

    2002-12-01

    In traditional packet voice or the emerging 2.5G and 3G wireless data services, smooth and timely delivery of audio is an essential requirement in Quality of Service (QoS) provision. It has been shown in our previous work that, by adapting time-scale modification to audio signals, an adaptive play-out algorithm can be designed to minimize packet dropping at the receiver end. By stretching the audio frame duration up and down, the proposed algorithm could adapt quickly to accommodate fluctuating delays including delay spikes. In this paper, we will address the packet audio QoS with emphasis on end-to-end delay, packet loss, and delay jitter. The characteristics of delay and loss will be discussed. Adaptive playback will enhance the audio quality by adapting to the transmission delay jitter and delay spike. Coupled with Forward Error Correction (FEC) schemes, the proposed delay and loss concealment algorithm achieves less overall application loss rate without sacrificing on the average end-to-end delay. The optimal solution of such algorithms will be discussed. We also investigate the stretching-ratio transition effect on perceived audio quality by measuring the objective Perceptual Evaluation of Speech Quality (PESQ) Mean Opinion Score (MOS).

  6. Electronic-To-Optical-To-Electronic Packet-Data Conversion

    NASA Technical Reports Server (NTRS)

    Monacos, Steve

    1996-01-01

    Space-time multiplexer (STM) cell-based communication system designed to take advantage of both high throughput attainable in optical transmission links and flexibility and functionality of electronic processing, storage, and switching. Long packets segmented and transmitted optically by wavelength-division multiplexing. Performs optoelectronic and protocol conversion between electronic "store-and-forward" protocols and optical "hot-potato" protocols.

  7. Canada and the United States. Perspective. Learning Activity Packet.

    ERIC Educational Resources Information Center

    Maine Univ., Orono. New England - Atlantic Provinces - Quebec Center.

    The similarities and differences of Canada and the United States are explored in this Learning Activity Packet (LAP). Ten learning objectives are given which encourage students to examine: 1) the misconceptions Americans and Canadians have about each other and their ways of life; 2) the effect and influence of French and English exploration and…

  8. SLIAG Advocacy Packet: A Guide for Community-Based Organizations.

    ERIC Educational Resources Information Center

    National Council of La Raza, Washington, DC.

    This packet of materials is designed as a basic guide for community-based organizations (CBOs) interested in tracking the use of State Legalization Impact Assistance Grants (SLIAG) funds and in advocating that they be used efficiently and effectively. The SLIAG program was created under the Immigration Reform and Control Act of 1986 (IRCA) to…

  9. Resonance-assisted decay of nondispersive wave packets.

    PubMed

    Wimberger, Sandro; Schlagheck, Peter; Eltschka, Christopher; Buchleitner, Andreas

    2006-07-28

    We present a quantitative semiclassical theory for the decay of nondispersive electronic wave packets in driven, ionizing Rydberg systems. Statistically robust quantities are extracted combining resonance-assisted tunneling with subsequent transport across chaotic phase space and a final ionization step.

  10. [Geography Awareness Week Activity Packet, 1987 and 1988.

    ERIC Educational Resources Information Center

    Texas Alliance for Geographic Education, College Station.

    This resource packet contains materials and suggestions to integrate National Geography Awareness Week for 1987 and 1988 into elementary and secondary education in Texas. The materials for 1987 include: (1) a pamphlet for a balloon release; (2) a collection of ideas for student activities; (3) a description of two field experiences; (4) a…

  11. An integrated circuit/packet switched videoconferencing system

    SciTech Connect

    Kippenhan, H.A. Jr.; Lidinsky, W.P.; Roediger, G.A.; Watts, T.A.

    1995-11-01

    The HEP Network Resource Center (HEPNRC) at Fermilab and the Collider Detector Facility (CDF) collaboration have evolved a flexible, cost-effective, widely accessible videoconferencing system for use by high energy physics collaborations and others wishing to use videoconferencing. No current systems seemed to fully meet the needs of high energy physics collaborations. However, two classes of videoconferencing technology: circuit-switched and packet-switched, if integrated, might encompass most of HEP`s needs. It was also realized that, even with this integration, some additional functions were needed and some of the existing functions were not always wanted. HEPNRC with the help of members of the CDF collaboration set out to develop such an integrated system using as many existing subsystems and components as possible. This system is called VUPAC (Videoconferencing Using PAckets and Circuits). This paper begins with brief descriptions of the circuit-switched and packet-switched videoconferencing systems. Following this, issues and limitations of these systems are considered. Next the VUPAC system is described. Integration is accomplished primarily by a circuit/packet videoconferencing interface. Augmentation is centered in another subsystem called MSB (Multiport multisession Bridge). Finally, there is a discussion of the future work needed in the evolution of this system.

  12. Customized lifting multiwavelet packet information entropy for equipment condition identification

    NASA Astrophysics Data System (ADS)

    Chen, Jinglong; Zuo, Ming J.; Zi, Yanyang; He, Zhengjia; Yuan, Jing; Chen, Xuefeng

    2013-09-01

    Condition identification of mechanical equipment from vibration measurement data is significant to avoid economic loss caused by unscheduled breakdowns and catastrophic accidents. However, this task still faces challenges due to the complexity of equipment and the harsh environment. This paper provides a possibility for equipment condition identification by proposing a method called customized lifting multiwavelet packet information entropy. Benefiting from the properties of multi-resolution analysis and multiple wavelet basis functions, the multiwavelet method has advantages in characterizing non-stationary vibration signals. In order to realize the accurate detection and identification of the condition features, a customized lifting multiwavelet packet is constructed via a multiwavelet lifting scheme. Then the vibration signal from the mechanical equipment is processed by the customized lifting multiwavelet packet transform. The relative energy in each frequency band of the multiwavelet packet transform coefficients that equals a percentage of the whole signal energy is taken as the probability. The normalized information entropy is obtained based on the relative energy to describe the condition of a mechanical system. The proposed method is applied to the condition identification of a rolling mill and a demountable disk-drum aero-engine. The results support the feasibility of the proposed method in equipment condition identification.

  13. The Sphinx and the Pyramids at Giza. Educational Packet.

    ERIC Educational Resources Information Center

    Gagliano, Sara; Rapport, Wendy

    This packet of materials was created to accompany the exhibit "The Sphinx and the Pyramids: 100 Years of American Archaeology at Giza" at the Semitic Museum of Harvard University. The lessons and teacher's guide focus on the following: (1) "The Mystery of the Secret Tomb" where students take on the role of an archaeologist by attempting to solve a…

  14. Business Education: Learning Activities Packet for Office Education.

    ERIC Educational Resources Information Center

    Hawaii State Dept. of Education, Honolulu. Office of Instructional Services.

    These seventeen individualized learning activities packets (LAPs) are intended to relate essential competencies needed for entry or advancement in office occupations to the secondary level office education program and to assist students in achieving occupational proficiency in business careers. Each LAP contains some or all of the following…

  15. Application of Cellular Automata to Detection of Malicious Network Packets

    ERIC Educational Resources Information Center

    Brown, Robert L.

    2014-01-01

    A problem in computer security is identification of attack signatures in network packets. An attack signature is a pattern of bits that characterizes a particular attack. Because there are many kinds of attacks, there are potentially many attack signatures. Furthermore, attackers may seek to avoid detection by altering the attack mechanism so that…

  16. Teacher Education Packet for Illinois Core Curriculum in Agriculture.

    ERIC Educational Resources Information Center

    Hemp, Paul; Pepple, Jerry

    Developed for use by teacher educators or state staff, this teaching packet provides preservice or inservice training to teachers and prospective teachers on how to use the Illinois Core Curriculum in Agriculture. (It is recommended that copies of the Illinois core materials be available to the students.) Three problem areas are included:…

  17. Anti-Litter Curriculum Packet, Interdisciplinary, K-12.

    ERIC Educational Resources Information Center

    Tillis, Richard

    This curriculum packet consists of 20 illustrated cards with 15 activities designed to create "positive feelings" about a clean environment. Activities range from picture coloring for younger students, to lessons such as the economic and health problems litter creates for older students. Objectives include encouraging anti-litter and…

  18. Signal processing and tracking of arrivals in ocean acoustic tomography.

    PubMed

    Dzieciuch, Matthew A

    2014-11-01

    The signal processing for ocean acoustic tomography experiments has been improved to account for the scattering of the individual arrivals. The scattering reduces signal coherence over time, bandwidth, and space. In the typical experiment, scattering is caused by the random internal-wave field and results in pulse spreading (over arrival-time and arrival-angle) and wander. The estimator-correlator is an effective procedure that improves the signal-to-noise ratio of travel-time estimates and also provides an estimate of signal coherence. The estimator-correlator smoothes the arrival pulse at the expense of resolution. After an arrival pulse has been measured, it must be associated with a model arrival, typically a ray arrival. For experiments with thousands of transmissions, this is a tedious task that is error-prone when done manually. An error metric that accounts for peak amplitude as well as travel-time and arrival-angle can be defined. The Viterbi algorithm can then be adapted to the task of automated peak tracking. Repeatable, consistent results are produced that are superior to a manual tracking procedure. The tracking can be adjusted by tuning the error metric in logical, quantifiable manner. PMID:25373953

  19. 27 CFR 26.128 - Taxpayment at port of arrival.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Taxpayment at port of... Liquors and Articles Purchased by Tourists in Puerto Rico § 26.128 Taxpayment at port of arrival. If the... the port of arrival prior to release of the liquors or articles from customs custody. The tax may...

  20. 14 CFR 93.29 - International Arrival Authorizations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... point for the winter and summer scheduling seasons as follows. This section does not apply to arrivals at O'Hare from Canada by U.S. or Canadian air carriers. (1) Winter Scheduling Season. Upon request... Scheduling Season, as evidenced by the FAA's records, a corresponding Arrival Authorization for the...

  1. 7 CFR 322.7 - Notice of arrival.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ..., DEPARTMENT OF AGRICULTURE BEES, BEEKEEPING BYPRODUCTS, AND BEEKEEPING EQUIPMENT Importation of Adult Honeybees, Honeybee Germ Plasm, and Bees Other Than Honeybees From Approved Regions § 322.7 Notice of arrival. (a) At least 10 business days prior to the arrival in the United States of any shipment of...

  2. 7 CFR 322.7 - Notice of arrival.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ..., DEPARTMENT OF AGRICULTURE BEES, BEEKEEPING BYPRODUCTS, AND BEEKEEPING EQUIPMENT Importation of Adult Honeybees, Honeybee Germ Plasm, and Bees Other Than Honeybees From Approved Regions § 322.7 Notice of arrival. (a) At least 10 business days prior to the arrival in the United States of any shipment of...

  3. 7 CFR 322.7 - Notice of arrival.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ..., DEPARTMENT OF AGRICULTURE BEES, BEEKEEPING BYPRODUCTS, AND BEEKEEPING EQUIPMENT Importation of Adult Honeybees, Honeybee Germ Plasm, and Bees Other Than Honeybees From Approved Regions § 322.7 Notice of arrival. (a) At least 10 business days prior to the arrival in the United States of any shipment of...

  4. 19 CFR 4.2 - Reports of arrival of vessels.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... vessels. (a) Upon arrival in any port or place within the U.S., including, for purposes of this section... purposes of this part, “foreign port or place” includes a hovering vessel, as defined in 19 U.S.C. 1401(k... arriving either in distress or for the limited purpose of taking on certain supplies and departing within...

  5. 14 CFR 93.125 - Arrival or departure reservation.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 2 2010-01-01 2010-01-01 false Arrival or departure reservation. 93.125 Section 93.125 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION... § 93.125 Arrival or departure reservation. Except between 12 Midnight and 6 a.m. local time, no...

  6. Signal processing and tracking of arrivals in ocean acoustic tomography.

    PubMed

    Dzieciuch, Matthew A

    2014-11-01

    The signal processing for ocean acoustic tomography experiments has been improved to account for the scattering of the individual arrivals. The scattering reduces signal coherence over time, bandwidth, and space. In the typical experiment, scattering is caused by the random internal-wave field and results in pulse spreading (over arrival-time and arrival-angle) and wander. The estimator-correlator is an effective procedure that improves the signal-to-noise ratio of travel-time estimates and also provides an estimate of signal coherence. The estimator-correlator smoothes the arrival pulse at the expense of resolution. After an arrival pulse has been measured, it must be associated with a model arrival, typically a ray arrival. For experiments with thousands of transmissions, this is a tedious task that is error-prone when done manually. An error metric that accounts for peak amplitude as well as travel-time and arrival-angle can be defined. The Viterbi algorithm can then be adapted to the task of automated peak tracking. Repeatable, consistent results are produced that are superior to a manual tracking procedure. The tracking can be adjusted by tuning the error metric in logical, quantifiable manner.

  7. 9 CFR 93.804 - Declaration upon arrival.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Elephants, Hippopotami, Rhinoceroses, and Tapirs § 93.804 Declaration upon arrival. Upon arrival of an elephant, hippopotamus, rhinoceros, or tapir at a..., rhinoceros, or tapir was shipped; (h) The number, species, and purpose of importation of the...

  8. 9 CFR 93.804 - Declaration upon arrival.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Elephants, Hippopotami, Rhinoceroses, and Tapirs § 93.804 Declaration upon arrival. Upon arrival of an elephant, hippopotamus, rhinoceros, or tapir at a..., rhinoceros, or tapir was shipped; (h) The number, species, and purpose of importation of the...

  9. 9 CFR 93.804 - Declaration upon arrival.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Elephants, Hippopotami, Rhinoceroses, and Tapirs § 93.804 Declaration upon arrival. Upon arrival of an elephant, hippopotamus, rhinoceros, or tapir at a..., rhinoceros, or tapir was shipped; (h) The number, species, and purpose of importation of the...

  10. 9 CFR 93.804 - Declaration upon arrival.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Elephants, Hippopotami, Rhinoceroses, and Tapirs § 93.804 Declaration upon arrival. Upon arrival of an elephant, hippopotamus, rhinoceros, or tapir at a..., rhinoceros, or tapir was shipped; (h) The number, species, and purpose of importation of the...

  11. 9 CFR 93.804 - Declaration upon arrival.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... FOR MEANS OF CONVEYANCE AND SHIPPING CONTAINERS Elephants, Hippopotami, Rhinoceroses, and Tapirs § 93.804 Declaration upon arrival. Upon arrival of an elephant, hippopotamus, rhinoceros, or tapir at a..., rhinoceros, or tapir was shipped; (h) The number, species, and purpose of importation of the...

  12. 19 CFR 123.61 - Baggage arriving in baggage car.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 19 Customs Duties 1 2012-04-01 2012-04-01 false Baggage arriving in baggage car. 123.61 Section... OF THE TREASURY CBP RELATIONS WITH CANADA AND MEXICO Baggage § 123.61 Baggage arriving in baggage car... cars....

  13. 19 CFR 123.61 - Baggage arriving in baggage car.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 19 Customs Duties 1 2013-04-01 2013-04-01 false Baggage arriving in baggage car. 123.61 Section... OF THE TREASURY CBP RELATIONS WITH CANADA AND MEXICO Baggage § 123.61 Baggage arriving in baggage car... cars....

  14. 19 CFR 123.61 - Baggage arriving in baggage car.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 19 Customs Duties 1 2014-04-01 2014-04-01 false Baggage arriving in baggage car. 123.61 Section... OF THE TREASURY CBP RELATIONS WITH CANADA AND MEXICO Baggage § 123.61 Baggage arriving in baggage car... cars....

  15. 19 CFR 123.61 - Baggage arriving in baggage car.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 19 Customs Duties 1 2010-04-01 2010-04-01 false Baggage arriving in baggage car. 123.61 Section... car. An inward foreign manifest on Customs Form 7533 shall be used for all baggage arriving in baggage cars....

  16. 8 CFR 251.1 - Arrival manifests and lists.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 8 Aliens and Nationality 1 2014-01-01 2014-01-01 false Arrival manifests and lists. 251.1 Section 251.1 Aliens and Nationality DEPARTMENT OF HOMELAND SECURITY IMMIGRATION REGULATIONS ARRIVAL AND... or agent of the vessel shall indicate in writing immediately below the name of the last alien...

  17. 7 CFR 322.7 - Notice of arrival.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ..., DEPARTMENT OF AGRICULTURE BEES, BEEKEEPING BYPRODUCTS, AND BEEKEEPING EQUIPMENT Importation of Adult Honeybees, Honeybee Germ Plasm, and Bees Other Than Honeybees From Approved Regions § 322.7 Notice of arrival. (a) At least 10 business days prior to the arrival in the United States of any shipment of...

  18. 7 CFR 322.7 - Notice of arrival.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ..., DEPARTMENT OF AGRICULTURE BEES, BEEKEEPING BYPRODUCTS, AND BEEKEEPING EQUIPMENT Importation of Adult Honeybees, Honeybee Germ Plasm, and Bees Other Than Honeybees From Approved Regions § 322.7 Notice of arrival. (a) At least 10 business days prior to the arrival in the United States of any shipment of...

  19. Divorce and asynchronous arrival in common terns, Sterna hirundo.

    PubMed

    GonzáLez-SolíS; Becker; Wendeln

    1999-11-01

    We investigated which of three hypotheses (better option, incompatibility or asynchronous arrival) best explains divorce in the common tern. One partner did not return the next year in 18.5% of 150 pairs. Among the 106 pairs in which both mates returned, the divorce rate was 18.9%. We found no significant differences in: breeding performance or condition in relation to the probability of divorce; quality of previous mates and new mates, mean age in relation to pair bond status; breeding success before and after divorce nor did this differ from breeding success of reunited pairs. Hence the better option and incompatibility hypotheses were not supported. However, divorce was more likely in pairs in which mates arrived asynchronously on the breeding grounds, supporting the asynchronous arrival hypothesis. Median arrival asynchrony for divorced pairs was 7.5 days and for reunited pairs 2 days; mates arriving more than 16 days apart always split up. About 20% of divorced birds lost breeding status in the year of divorce, probably as a consequence of their late arrival. Our results suggest that terns search for a new mate as soon as they arrive on the breeding grounds and that mates remain faithful to each other to avoid the costs of searching for a new partner. Thus, synchrony in arrival facilitates pair bond maintenance rather than asynchrony promoting divorce, since divorce appears to be a side-effect of asynchrony and not an active decision. Copyright 1999 The Association for the Study of Animal Behaviour. PMID:10564616

  20. 27 CFR 26.128 - Taxpayment at port of arrival.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Taxpayment at port of arrival. 26.128 Section 26.128 Alcohol, Tobacco Products and Firearms ALCOHOL AND TOBACCO TAX AND TRADE... Liquors and Articles Purchased by Tourists in Puerto Rico § 26.128 Taxpayment at port of arrival. If...

  1. Evaluation of Post-Arrival Programs and Services.

    ERIC Educational Resources Information Center

    Australian Inst. of Multicultural Affairs, Melbourne (Australia).

    This book assesses the effectiveness of recommendations implemented after the release of the Australian government's "Report of the Review of Post-Arrival Programs and Services for Migrants" in 1977. In general, the implementation of the Report's proposals has been of substantial benefit to migrants (both newly arrived and longer resident), to…

  2. 9 CFR 98.7 - Declaration upon arrival.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... CERTAIN ANIMAL EMBRYOS AND ANIMAL SEMEN Ruminant and Swine Embryos from Regions Free of Rinderpest and Foot-and-Mouth Disease; and Embryos of Horses and Asses § 98.7 Declaration upon arrival. Upon arrival of an embryo at a port of entry, the importer or the importer's agent shall notify APHIS of...

  3. 9 CFR 98.7 - Declaration upon arrival.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... CERTAIN ANIMAL EMBRYOS AND ANIMAL SEMEN Ruminant and Swine Embryos from Regions Free of Rinderpest and Foot-and-Mouth Disease; and Embryos of Horses and Asses § 98.7 Declaration upon arrival. Upon arrival of an embryo at a port of entry, the importer or the importer's agent shall notify APHIS of...

  4. 9 CFR 98.7 - Declaration upon arrival.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... CERTAIN ANIMAL EMBRYOS AND ANIMAL SEMEN Ruminant and Swine Embryos from Regions Free of Rinderpest and Foot-and-Mouth Disease; and Embryos of Horses and Asses § 98.7 Declaration upon arrival. Upon arrival of an embryo at a port of entry, the importer or the importer's agent shall notify APHIS of...

  5. 9 CFR 98.7 - Declaration upon arrival.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... CERTAIN ANIMAL EMBRYOS AND ANIMAL SEMEN Ruminant and Swine Embryos from Regions Free of Rinderpest and Foot-and-Mouth Disease; and Embryos of Horses and Asses § 98.7 Declaration upon arrival. Upon arrival of an embryo at a port of entry, the importer or the importer's agent shall notify APHIS of...

  6. 9 CFR 98.7 - Declaration upon arrival.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... CERTAIN ANIMAL EMBRYOS AND ANIMAL SEMEN Ruminant and Swine Embryos from Regions Free of Rinderpest and Foot-and-Mouth Disease; and Embryos of Horses and Asses § 98.7 Declaration upon arrival. Upon arrival of an embryo at a port of entry, the importer or the importer's agent shall notify APHIS of...

  7. 19 CFR 123.61 - Baggage arriving in baggage car.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 19 Customs Duties 1 2011-04-01 2011-04-01 false Baggage arriving in baggage car. 123.61 Section... OF THE TREASURY CBP RELATIONS WITH CANADA AND MEXICO Baggage § 123.61 Baggage arriving in baggage car... cars....

  8. TRACON Aircraft Arrival Planning and Optimization Through Spatial Constraint Satisfaction

    NASA Technical Reports Server (NTRS)

    Bergh, Christopher P.; Krzeczowski, Kenneth J.; Davis, Thomas J.; Denery, Dallas G. (Technical Monitor)

    1995-01-01

    A new aircraft arrival planning and optimization algorithm has been incorporated into the Final Approach Spacing Tool (FAST) in the Center-TRACON Automation System (CTAS) developed at NASA-Ames Research Center. FAST simulations have been conducted over three years involving full-proficiency, level five air traffic controllers from around the United States. From these simulations an algorithm, called Spatial Constraint Satisfaction, has been designed, coded, undergone testing, and soon will begin field evaluation at the Dallas-Fort Worth and Denver International airport facilities. The purpose of this new design is an attempt to show that the generation of efficient and conflict free aircraft arrival plans at the runway does not guarantee an operationally acceptable arrival plan upstream from the runway -information encompassing the entire arrival airspace must be used in order to create an acceptable aircraft arrival plan. This new design includes functions available previously but additionally includes necessary representations of controller preferences and workload, operationally required amounts of extra separation, and integrates aircraft conflict resolution. As a result, the Spatial Constraint Satisfaction algorithm produces an optimized aircraft arrival plan that is more acceptable in terms of arrival procedures and air traffic controller workload. This paper discusses the current Air Traffic Control arrival planning procedures, previous work in this field, the design of the Spatial Constraint Satisfaction algorithm, and the results of recent evaluations of the algorithm.

  9. Cell aggregation and sedimentation.

    PubMed

    Davis, R H

    1995-01-01

    The aggregation of cells into clumps or flocs has been exploited for decades in such applications as biological wastewater treatment, beer brewing, antibiotic fermentation, and enhanced sedimentation to aid in cell recovery or retention. More recent research has included the use of cell aggregation and sedimentation to selectively separate subpopulations of cells. Potential biotechnological applications include overcoming contamination, maintaining plasmid-bearing cells in continuous fermentors, and selectively removing nonviable hybridoma cells from perfusion cultures.

  10. Exploring multiple degrees of freedom in Rydberg wave packets

    NASA Astrophysics Data System (ADS)

    Wen, Haidan

    2006-12-01

    Recent advances in the study of Rydberg atoms have focused on the control, manipulation and detection of Rydberg wave packets using novel external fields such as half-cycle pulses. The radial degree of freedom has been controlled and used to process information encoded in Rydberg states. However, these previous experiments make use of only a single degree of freedom, restricting the potential of other degrees of freedom for quantum computing in Rydberg atoms. In this dissertation, we explore the control and detection of other degrees of freedom in an electron wave packet, such as the angular momentum quantum number ℓ, the magnetic quantum number m and the electron spin; so that the full range of quantum numbers can participate in information processing. We first propose an interferometric control of the population of angular momentum states using two time-delayed phase-locked ultrafast laser pulses. The population of arbitrary angular momentum states can be greatly enhanced by optimizing the time delay and the relative phases between two laser pulses. We then qualitatively measure the evolution of angular momentum components in Stark wave packets by a weak half-cycle pulse (HCP). This measurement utilizes a time-delayed HCP and is proved to be effective for detecting various aspects of wave packet dynamics, particularly, the evolution of non-stationary states. The technique relies on the fact that the HCP redistributes the eigenstate populations and induced the population variation which reflects the evolution of eigenstate phases. Finally, we find that the dynamics of m-states could be highly correlated with the internal degree of freedom of the electron, the spin. We study the effect of spin-orbit coupling on the wave packet dynamics and observe the angular precession of a Rydberg wave packet. The population redistribution from p to s states is highly sensitive to the polarization of the HCP and changes with the precession of the electron orbit. We obtain the

  11. Modeling Weather Impact on Airport Arrival Miles-in-Trail Restrictions

    NASA Technical Reports Server (NTRS)

    Wang, Yao; Grabbe, Shon

    2013-01-01

    When the demand for either a region of airspace or an airport approaches or exceeds the available capacity, miles-in-trail (MIT) restrictions are the most frequently issued traffic management initiatives (TMIs) that are used to mitigate these imbalances. Miles-intrail operations require aircraft in a traffic stream to meet a specific inter-aircraft separation in exchange for maintaining a safe and orderly flow within the stream. This stream of aircraft can be departing an airport, over a common fix, through a sector, on a specific route or arriving at an airport. This study begins by providing a high-level overview of the distribution and causes of arrival MIT restrictions for the top ten airports in the United States. This is followed by an in-depth analysis of the frequency, duration and cause of MIT restrictions impacting the Hartsfield-Jackson Atlanta International Airport (ATL) from 2009 through 2011. Then, machine-learning methods for predicting (1) situations in which MIT restrictions for ATL arrivals are implemented under low demand scenarios, and (2) days in which a large number of MIT restrictions are required to properly manage and control ATL arrivals are presented. More specifically, these predictions were accomplished by using an ensemble of decision trees with Bootstrap aggregation (BDT) and supervised machine learning was used to train the BDT binary classification models. The models were subsequently validated using data cross validation methods. When predicting the occurrence of arrival MIT restrictions under low demand situations, the model was able to achieve over all accuracy rates ranging from 84% to 90%, with false alarm ratios ranging from 10% to 15%. In the second set of studies designed to predict days on which a high number of MIT restrictions were required, overall accuracy rates of 80% were achieved with false alarm ratios of 20%. Overall, the predictions proposed by the model give better MIT usage information than what has been

  12. Children's Literature with a Science Emphasis: Twenty Teacher-Developed K-8 Activity Packets.

    ERIC Educational Resources Information Center

    Butler, Malcolm B.

    This document features 10 science activity packets developed for elementary students by science teachers in a graduate seminar. The activity packets were designed to cover existing commercial children's books on specific content areas. The 10 activity packets are: (1) "Bringing the Rain to Kapiti Plain," which explains the water cycle; (2)…

  13. Data relationship degree-based clustering data aggregation for VANET

    NASA Astrophysics Data System (ADS)

    Kumar, Rakesh; Dave, Mayank

    2016-03-01

    Data aggregation is one of the major needs of vehicular ad hoc networks (VANETs) due to the constraints of resources. Data aggregation in VANET can reduce the data redundancy in the process of data gathering and thus conserving the bandwidth. In realistic applications, it is always important to construct an effective route strategy that optimises not only communication cost but also the aggregation cost. Data aggregation at the cluster head by individual vehicle causes flooding of the data, which results in maximum latency and bandwidth consumption. Another approach of data aggregation in VANET is sending local representative data based on spatial correlation of sampled data. In this article, we emphasise on the problem that recent spatial correlation data models of vehicles in VANET are not appropriate for measuring the correlation in a complex and composite environment. Moreover, the data represented by these models is generally inaccurate when compared to the real data. To minimise this problem, we propose a group-based data aggregation method that uses data relationship degree (DRD). In the proposed approach, DRD is a spatial relationship measurement parameter that measures the correlation between a vehicle's data and its neighbouring vehicles' data. The DRD clustering method where grouping of vehicle's data is done based on the available data and its correlation is presented in detail. Results prove that the representative data using proposed approach have a low distortion and provides an improvement in packet delivery ratio and throughput (up to of 10.84% and 24.82% respectively) as compared to the other state-of-the-art solutions like Cluster-Based Accurate Syntactic Compression of Aggregated Data in VANETs.

  14. Fibronectin Aggregation and Assembly

    PubMed Central

    Ohashi, Tomoo; Erickson, Harold P.

    2011-01-01

    The mechanism of fibronectin (FN) assembly and the self-association sites are still unclear and contradictory, although the N-terminal 70-kDa region (I1–9) is commonly accepted as one of the assembly sites. We previously found that I1–9 binds to superfibronectin, which is an artificial FN aggregate induced by anastellin. In the present study, we found that I1–9 bound to the aggregate formed by anastellin and a small FN fragment, III1–2. An engineered disulfide bond in III2, which stabilizes folding, inhibited aggregation, but a disulfide bond in III1 did not. A gelatin precipitation assay showed that I1–9 did not interact with anastellin, III1, III2, III1–2, or several III1–2 mutants including III1–2KADA. (In contrast to previous studies, we found that the III1–2KADA mutant was identical in conformation to wild-type III1–2.) Because I1–9 only bound to the aggregate and the unfolding of III2 played a role in aggregation, we generated a III2 domain that was destabilized by deletion of the G strand. This mutant bound I1–9 as shown by the gelatin precipitation assay and fluorescence resonance energy transfer analysis, and it inhibited FN matrix assembly when added to cell culture. Next, we introduced disulfide mutations into full-length FN. Three disulfide locks in III2, III3, and III11 were required to dramatically reduce anastellin-induced aggregation. When we tested the disulfide mutants in cell culture, only the disulfide bond in III2 reduced the FN matrix. These results suggest that the unfolding of III2 is one of the key factors for FN aggregation and assembly. PMID:21949131

  15. Scheduling and Separating Departures Crossing Arrival Flows in Shared Airspace

    NASA Technical Reports Server (NTRS)

    Chevalley, Eric; Parke, Bonny K.; Lee, Paul; Omar, Faisal; Lee, Hwasoo; Beinert, Nancy; Kraut, Joshua M.; Palmer, Everett

    2013-01-01

    Flight efficiency and reduction of flight delays are among the primary goals of NextGen. In this paper, we propose a concept of shared airspace where departures fly across arrival flows, provided gaps are available in these flows. We have explored solutions to separate departures temporally from arrival traffic and pre-arranged procedures to support controllers' decisions. We conducted a Human-in-the-Loop simulation and assessed the efficiency and safety of 96 departures from the San Jose airport (SJC) climbing across the arrival airspace of the Oakland and San Francisco arrival flows. In our simulation, the SJC tower had a tool to schedule departures to fly across predicted gaps in the arrival flow. When departures were mistimed and separation could not be ensured, a safe but less efficient route was provided to the departures to fly under the arrival flows. A coordination using a point-out procedure allowed the arrival controller to control the SJC departures right after takeoff. We manipulated the accuracy of departure time (accurate vs. inaccurate) as well as which sector took control of the departures after takeoff (departure vs. arrival sector) in a 2x2 full factorial plan. Results show that coordination time decreased and climb efficiency increased when the arrival sector controlled the aircraft right after takeoff. Also, climb efficiency increased when the departure times were more accurate. Coordination was shown to be a critical component of tactical operations in shared airspace. Although workload, coordination, and safety were judged by controllers as acceptable in the simulation, it appears that in the field, controllers would need improved tools and coordination procedures to support this procedure.

  16. Collaborative Arrival Planning: Data Sharing and User Preference Tools

    NASA Technical Reports Server (NTRS)

    Zelenka, Richard E.; Edwards, Thomas A. (Technical Monitor)

    1998-01-01

    Air traffic growth and air carrier economic pressures have motivated efforts to increase the flexibility of the air traffic management process and change the relationship between the air traffic control service provider and the system user. One of the most visible of these efforts is the U.S. government/industry "free flight" initiative, in which the service provider concentrates on safety and cross-airline fairness, and the user on their business objectives and operating preferences, including selecting their own path and speed in real-time. In the terminal arrival phase of flight, severe restrictions and rigid control are currently placed on system users, typically without regard for individual user operational preferences. Airborne delays applied to arriving aircraft into capacity constrained airports are imposed on a first-come, first-serve basis, and thus do not allow the system user to plan for or prioritize late arrivals, or to economically optimize their arrival sequence. A central tenant of the free-flight operating paradigm is collaboration between service providers and users in reaching air traffic management decisions. Such collaboration would be particularly beneficial to an airline's "hub" operation, where off-schedule arrival aircraft are a consistent problem, as they cause serious air-port ramp difficulties, rippling airline scheduling effects, and result in large economic inefficiencies. Greater collaboration can also lead to increased airport capacity and decrease the severity of over-capacity rush periods. In the NASA Collaborative Arrival Planning (CAP) project, both independent exchange of real-time data between the service provider and system user and collaborative decision support tools are addressed. Data exchange of real-time arrival scheduling, airspace management, and air carrier fleet data between the FAA service provider and an air carrier is being conducted and evaluated. Collaborative arrival decision support tools to allow intra

  17. Drought in Africa caused delayed arrival of European songbirds.

    PubMed

    Tøttrup, A P; Klaassen, R H G; Kristensen, M W; Strandberg, R; Vardanis, Y; Lindström, Å; Rahbek, C; Alerstam, T; Thorup, K

    2012-12-01

    Despite an overall advancement in breeding area arrival, one of the latest spring arrivals in northwest Europe since 1950 of several trans-Saharan songbird species occurred in 2011. Year-round tracking of red-backed shrikes and thrush nightingales revealed that the cause of the delay was a prolongation of stopover time during spring migration at the Horn of Africa, which was affected by extreme drought. Our results help to establish a direct link at the individual level between changes in local climate during migration and arrival and breeding condition in Europe thousands of kilometers further north.

  18. Concept of Operations for Interval Management Arrivals and Approach

    NASA Technical Reports Server (NTRS)

    Hicok, Daniel S.; Barmore, Bryan E.

    2016-01-01

    This paper presents the concept of operations for interval management operations to be deployed in the US National Airspace System (NAS) by the Federal Aviation Administration (FAA) after 2020. The use of interval management operations is described that begin in en route airspace and continue to a termination point inside the arrival terminal area, in a terminal environment that includes other arrival management tools such as arrival metering, Ground-based Interval Management - Spacing (GIM-S), and Terminal Sequencing and Spacing (TSAS). The roles of Air Traffic Controllers and Flight Crews and the ground automation tools that are used by Air Traffic Controllers to enable the primary operation and variations are described.

  19. Flame Arrival Measurement By Instrumented Spark Plug or Head Gasket

    1995-04-10

    PLUGBIN was developed to support Sandia technologies involving instrumented head gaskets and spark plugs for engine research and development. It acquires and processes measurements of flame arrival and pressure from a spark ignition. Flame arrival is determined from analog ionization-probe or visible-emission signals, and/or digitial signals from a dedicated flame arrival measurement processor. The pressure measurements are analyzed to determine the time of peak pressure and the time to burn 10 and 90 percent ofmore » the charge. Histograms are then calculated and displayed for each measurement.« less

  20. Investigation into the formation of charge packets in polyethylene: Experiment and simulation

    NASA Astrophysics Data System (ADS)

    Zhao, J.; Chen, G.; Lewin, P. L.

    2012-08-01

    The phenomenon of charge packet has been reported in polymeric insulation materials under the application of dc electric fields in recent decades. It is noted that such charge packets could lead to substantial modification of local electric stress, which increases the possibility of failure of insulating materials. The physics of charge packets has not yet been revealed clearly. In this paper, the dynamics of positive charge packets in polyethylene is observed using the pulsed electro-acoustic technique. Negative differential mobility of positive charge carrier is found, which is believed to be crucial to the formation of charge packets. This negative differential mobility is introduced into a bipolar charge transport model to simulate the packet-like space charge in polymers. Simulation results show that not only the negative differential mobility but also weaker trapping characteristic are required to generate a positive charge packet in polyethylene under dc stress.

  1. Technology meets aggregate

    SciTech Connect

    Wilson, C.; Swan, C.

    2007-07-01

    New technology carried out at Tufts University and the University of Massachusetts on synthetic lightweight aggregate has created material from various qualities of fly ash from coal-fired power plants for use in different engineered applications. In pilot scale manufacturing tests an 'SLA' containing 80% fly ash and 20% mixed plastic waste from packaging was produced by 'dry blending' mixed plastic with high carbon fly ash. A trial run was completed to produce concrete masonry unit (CMU) blocks at a full-scale facility. It has been shown that SLA can be used as a partial substitution of a traditional stone aggregate in hot asphalt mix. 1 fig., 2 photos.

  2. Second Harmonic Generation of Nanoscale Phonon Wave Packets

    NASA Astrophysics Data System (ADS)

    Bojahr, A.; Gohlke, M.; Leitenberger, W.; Pudell, J.; Reinhardt, M.; von Reppert, A.; Roessle, M.; Sander, M.; Gaal, P.; Bargheer, M.

    2015-11-01

    Phonons are often regarded as delocalized quasiparticles with certain energy and momentum. The anharmonic interaction of phonons determines macroscopic properties of the solid, such as thermal expansion or thermal conductivity, and a detailed understanding becomes increasingly important for functional nanostructures. Although phonon-phonon scattering processes depicted in simple wave-vector diagrams are the basis of theories describing these macroscopic phenomena, experiments directly accessing these coupling channels are scarce. We synthesize monochromatic acoustic phonon wave packets with only a few cycles to introduce nonlinear phononics as the acoustic counterpart to nonlinear optics. Control of the wave vector, bandwidth, and consequently spatial extent of the phonon wave packets allows us to observe nonlinear phonon interaction, in particular, second harmonic generation, in real time by wave-vector-sensitive Brillouin scattering with x-rays and optical photons.

  3. Wave packet dynamics in the optimal superadiabatic approximation

    NASA Astrophysics Data System (ADS)

    Betz, V.; Goddard, B. D.; Manthe, U.

    2016-06-01

    We explain the concept of superadiabatic representations and show how in the context of electronically non-adiabatic transitions they lead to an explicit formula that can be used to predict transitions at avoided crossings. Based on this formula, we present a simple method for computing wave packet dynamics across avoided crossings. Only knowledge of the adiabatic potential energy surfaces near the avoided crossing is required for the computation. In particular, this means that no diabatization procedure is necessary, the adiabatic electronic energies can be computed on the fly, and they only need to be computed to higher accuracy when an avoided crossing is detected. We test the quality of our method on the paradigmatic example of photo-dissociation of NaI, finding very good agreement with results of exact wave packet calculations.

  4. Probing surface states with many-body wave packet scattering

    NASA Astrophysics Data System (ADS)

    Damon, F.; Georgeot, B.; Guéry-Odelin, D.

    2016-07-01

    The scattering of 1D matter wave bright solitons on attractive potentials enables one to populate bound states, a feature impossible with noninteracting wave packets. Compared to noninteracting states, the populated states are renormalized by the attractive interactions between atoms and keep the same topology. This renormalization can even transform a virtual state into a bound state. By switching off adiabatically the interactions, the trapped wave packets converge towards the true noninteracting bound states. Our numerical studies show how such scattering experiments can reveal and characterize the surface states of a periodic structure whose translational invariance has been broken. We provide evidence that the corresponding 3D regime should be accessible with current techniques.

  5. Exciton-polariton localized wave packets in a microcavity

    NASA Astrophysics Data System (ADS)

    Voronych, Oksana; Buraczewski, Adam; Matuszewski, MichałÂ; Stobińska, Magdalena

    2016-06-01

    We investigate the possibility of creating X waves, or localized wave packets, in resonantly excited exciton-polariton superfluids. We demonstrate the existence of X-wave traveling solutions in the coupled exciton-photon system past the inflection point, where the effective mass of lower polaritons is negative in the direction perpendicular to the wave vector of the pumping beam. Contrary to the case of bright solitons, X waves do not require nonlinearity for sustaining their shape. Nevertheless, we show that nonlinearity is important for their dynamics, as it allows for their spontaneous formation from an initial Gaussian wave packet. Unique properties of exciton-polaritons may lead to applications of their X waves in long-distance signal propagation inside novel integrated optoelectronic circuits based on excitons.

  6. Very low bit rate voice for packetized mobile applications

    SciTech Connect

    Knittle, C.D.; Malone, K.T.

    1991-01-01

    Transmitting digital voice via packetized mobile communications systems that employ relatively short packet lengths and narrow bandwidths often necessitates very low bit rate coding of the voice data. Sandia National Laboratories is currently developing an efficient voice coding system operating at 800 bits per second (bps). The coding scheme is a modified version of the 2400 bps NSA LPC-10e standard. The most significant modification to the LPC-10e scheme is the vector quantization of the line spectrum frequencies associated with the synthesis filters. An outline of a hardware implementation for the 800 bps coder is presented. The speech quality of the coder is generally good, although speaker recognition is not possible. Further research is being conducted to reduce the memory requirements and complexity of the vector quantizer, and to increase the quality of the reconstructed speech. 4 refs., 2 figs., 3 tabs.

  7. Very low bit rate voice for packetized mobile applications

    SciTech Connect

    Knittle, C.D.; Malone, K.T. )

    1991-01-01

    This paper reports that transmitting digital voice via packetized mobile communications systems that employ relatively short packet lengths and narrow bandwidths often necessitates very low bit rate coding of the voice data. Sandia National Laboratories is currently developing an efficient voice coding system operating at 800 bits per second (bps). The coding scheme is a modified version of the 2400 bps NSA LPC-10e standard. The most significant modification to the LPC-10e scheme is the vector quantization of the line spectrum frequencies associated with the synthesis filters. An outline of a hardware implementation for the 800 bps coder is presented. The speech quality of the coder is generally good, although speaker recognition is not possible. Further research is being conducted to reduce the memory requirements and complexity of the vector quantizer, and to increase the quality of the reconstructed speech. This work may be of use dealing with nuclear materials.

  8. Wave packet dynamics in the optimal superadiabatic approximation.

    PubMed

    Betz, V; Goddard, B D; Manthe, U

    2016-06-14

    We explain the concept of superadiabatic representations and show how in the context of electronically non-adiabatic transitions they lead to an explicit formula that can be used to predict transitions at avoided crossings. Based on this formula, we present a simple method for computing wave packet dynamics across avoided crossings. Only knowledge of the adiabatic potential energy surfaces near the avoided crossing is required for the computation. In particular, this means that no diabatization procedure is necessary, the adiabatic electronic energies can be computed on the fly, and they only need to be computed to higher accuracy when an avoided crossing is detected. We test the quality of our method on the paradigmatic example of photo-dissociation of NaI, finding very good agreement with results of exact wave packet calculations. PMID:27305998

  9. Stochastic acceleration of ions driven by Pc1 wave packets

    SciTech Connect

    Khazanov, G. V. Sibeck, D. G.; Tel'nikhin, A. A.; Kronberg, T. K.

    2015-07-15

    The stochastic motion of protons and He{sup +} ions driven by Pc1 wave packets is studied in the context of resonant particle heating. Resonant ion cyclotron heating typically occurs when wave powers exceed 10{sup −4} nT{sup 2}/Hz. Gyroresonance breaks the first adiabatic invariant and energizes keV ions. Cherenkov resonances with the electrostatic component of wave packets can also accelerate ions. The main effect of this interaction is to accelerate thermal protons to the local Alfven speed. The dependencies of observable quantities on the wave power and plasma parameters are determined, and estimates for the heating extent and rate of particle heating in these wave-particle interactions are shown to be in reasonable agreement with known empirical data.

  10. Future directions in packet radio architectures and protocols

    NASA Astrophysics Data System (ADS)

    Shacham, Nachum; Westcott, Jil

    1987-01-01

    The technology of packet switching over multihop, multiple-access channels has evolved to the point at which its protocols can now support internetwork operation of medium-size networks whose nodes possess some degree of mobility. As regards the needs and challenges of the future operating environment, it is clear that these can be met only by enhancing the packet radio architecture and its protocols. Several enhancements that allow the organization of large, dynamic networks that can operate over multiple channels, adapt to varying conditions, and possess self-monitoring and self-control capabilities are discussed. As these areas are examined, the attendant issues and tradeoffs are discussed; in addition, some protocols and information regarding their performance are presented.

  11. Two-dimensional attosecond electron wave-packet interferometry.

    PubMed

    Xie, Xinhua

    2015-05-01

    We propose a two-dimensional interferometry based on the electron wave-packet interference by using a cycle-shaped orthogonally polarized two-color laser field. With such a method, the subcycle and intercycle interferences can be disentangled into different directions in the measured photoelectron momentum spectra. The Coulomb influence can be minimized and the overlapping of interference fringes with the complicated low-energy structures can be avoided as well. The contributions of the excitation effect and the long-range Coulomb potential can be traced in the Fourier domain of the photoelectron distribution. Because of these advantages, precise information on valence electron dynamics of atoms or molecules with attosecond temporal resolution and additional spatial information with angstrom resolution can be obtained with the two-dimensional electron wave-packet interferometry.

  12. The Interference of the Dynamically Squeezed Vibrational Wave Packets

    NASA Technical Reports Server (NTRS)

    Vinogradov, An. V.; Janszky, J.; Kobayashi, T.

    1996-01-01

    An electronic excitation of a molecule by a sequence of two femtosecond phase-locked laser pulses is considered. In this case the interference between the vibrational wave packets induced by each of the subpulses within a single molecule takes place. It is shown that due to the dynamical squeezing effect of a molecular vibrational state the interference of the vibrational wave packets allows one to measure the duration of a femtosecond laser pulse. This can be achieved experimentally by measuring the dependence of the integral fluorescence of the excited molecule on the delay time between the subpulses. The interference can lead to a sharp peak (or to a down-fall) in that dependence, the width of which is equal to the duration of the laser pulse. It is shown that finite temperature of the medium is favorable for such an experiment.

  13. Two-Dimensional Attosecond Electron Wave-Packet Interferometry

    NASA Astrophysics Data System (ADS)

    Xie, Xinhua

    2015-05-01

    We propose a two-dimensional interferometry based on the electron wave-packet interference by using a cycle-shaped orthogonally polarized two-color laser field. With such a method, the subcycle and intercycle interferences can be disentangled into different directions in the measured photoelectron momentum spectra. The Coulomb influence can be minimized and the overlapping of interference fringes with the complicated low-energy structures can be avoided as well. The contributions of the excitation effect and the long-range Coulomb potential can be traced in the Fourier domain of the photoelectron distribution. Because of these advantages, precise information on valence electron dynamics of atoms or molecules with attosecond temporal resolution and additional spatial information with angstrom resolution can be obtained with the two-dimensional electron wave-packet interferometry.

  14. Formation of wave packets in electron diffraction on crystals

    NASA Astrophysics Data System (ADS)

    Lanning, Robert; Bahrim, Cristian

    2012-02-01

    Measurements of electron diffraction typically reveal the atomic structure of crystals and allow finding the length of chemical bonds. The effective electronic charge of each atom in the crystal acts upon the incident electron beam as a netting of narrow pinholes, and Fourier transforms the unique deBroglie wavelength of the projectile electron accelerated at fixed voltage into a wave packet. Using the uncertainty principle one can understand the mechanism that makes an incident electron to become a wave packet travelling inside the crystal at a group velocity identical with the initial speed of the projectile electron. Furthermore, the Pauli Exclusion Principle allows us to understand the fast passage of the projectile electron through the crystal and also, it allows the evaluation of the characteristic time for electron transmission. The project was sponsored by the STAIRSTEP program under the NSF-DUE grant# 0757057.

  15. Queues with Dropping Functions and General Arrival Processes.

    PubMed

    Chydzinski, Andrzej; Mrozowski, Pawel

    2016-01-01

    In a queueing system with the dropping function the arriving customer can be denied service (dropped) with the probability that is a function of the queue length at the time of arrival of this customer. The potential applicability of such mechanism is very wide due to the fact that by choosing the shape of this function one can easily manipulate several performance characteristics of the queueing system. In this paper we carry out analysis of the queueing system with the dropping function and a very general model of arrival process--the model which includes batch arrivals and the interarrival time autocorrelation, and allows for fitting the actual shape of the interarrival time distribution and its moments. For such a system we obtain formulas for the distribution of the queue length and the overall customer loss ratio. The analytical results are accompanied with numerical examples computed for several dropping functions.

  16. President Obama and Family Arrive at Kennedy Space Center

    NASA Video Gallery

    President Obama, accompanied by First Lady Michelle Obama and their two daughters, arrive aboard Air Force One at the Cape Canaveral AFS near NASA’s Kennedy Space Center at approximately 2 p.m. E...

  17. Countdown to Exploration Flight Test 1: The Arrival

    NASA Video Gallery

    As NASA counts down to the Exploration Flight Test 1 (EFT-1) of Orion in 2014, the spacecraft that will fly that mission has arrived at the launch site in Florida. Take a look inside the Operations...

  18. Webb Telescope Backplane Arrives at NASA Goddard Space Flight Center

    NASA Video Gallery

    Webb Telescope's Backplane arrived at Joint Base Andrews on Monday, August 24, 2015 aboard a U.S. Air Force C-5 cargo plane. The Backplane, inside the Space Telescope Transporter for Air Road and S...

  19. Concept of Operations for Interval Management Arrivals and Approach

    NASA Technical Reports Server (NTRS)

    Hicok, Daniel S.; Barmore, Bryan E.

    2016-01-01

    This paper presents the concept of operations for interval management operations to be deployed in the US National Airspace System (NAS) by the Federal Aviation Administration (FAA) Interval Management Program. The arrivals and approach operations are explored in detail including the primary operation and variations. The use of interval management operations is described that begin in en route airspace and continue to a termination point inside the arrival terminal area in the highly automated terminal environment that includes other arrival management tools such as arrival metering, Ground-based Interval Management - Spacing (GIM-S), and Terminal Sequencing and Spacing (TSAS). The roles of Air Traffic and Pilots and the ground automation tools that are used by Air Traffic Controllers to enable the operations are explored.

  20. Astronauts Armstrong and Scott arrive at Hickam Field, Hawaii

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Astronauts Neil A. Armstrong (center), command pilot, and David R. Scott, pilot, arrive at Hickam Field, Hawaii on their way from Naha, Okinawa, to Cape Kennedy, Florida. Astronaut Walter M. Schirra Jr. is at extreme left.

  1. Queues with Dropping Functions and General Arrival Processes

    PubMed Central

    Chydzinski, Andrzej; Mrozowski, Pawel

    2016-01-01

    In a queueing system with the dropping function the arriving customer can be denied service (dropped) with the probability that is a function of the queue length at the time of arrival of this customer. The potential applicability of such mechanism is very wide due to the fact that by choosing the shape of this function one can easily manipulate several performance characteristics of the queueing system. In this paper we carry out analysis of the queueing system with the dropping function and a very general model of arrival process—the model which includes batch arrivals and the interarrival time autocorrelation, and allows for fitting the actual shape of the interarrival time distribution and its moments. For such a system we obtain formulas for the distribution of the queue length and the overall customer loss ratio. The analytical results are accompanied with numerical examples computed for several dropping functions. PMID:26943171

  2. NASA's SOFIA Arrives in Christchurch, New Zealand, July 14, 2013

    NASA Video Gallery

    NASA's Stratospheric Observatory for Infrared Astronomy airborne observatory arrived at Christchurch International Airport, New Zealand, July 14 at 12:14 p.m. (New Zealand Standard Time) to investi...

  3. STS-85 Commander Curtis Brown arrives at SLF for TCDT

    NASA Technical Reports Server (NTRS)

    1997-01-01

    STS-85 Commander Curtis L. Brown, Jr., arrives at the Shuttle Landing Facility for his mission's Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. The liftoff of STS-85 is targeted for August 7, 1997.

  4. STS-85 Pilot Kent Rominger arrives at SLF for TCDT

    NASA Technical Reports Server (NTRS)

    1997-01-01

    STS-85 Pilot Kent V. Rominger arrives at the Shuttle Landing Facility for his mission's Terminal Countdown Demonstration Test (TCDT), a dress rehearsal for launch. The liftoff of STS-85 is targeted for August 7, 1997.

  5. IP- -: A Reduced Internet Protocol for Optical Packet Networking

    NASA Astrophysics Data System (ADS)

    Ohta, Masataka; Fujikawa, Kenji

    IP- - is proposed as an Internet Protocol suitable for optical packet networking. As optical routers require much faster control than electric ones and lack of optical buffers other than those by fiber delay lines requires fixed time control, Internet Protocols must be at least as simple as IPv4 and much simpler than IPv6. IP- - also addresses issues of IP address space exhaustion and IP routing table explosion.

  6. Ground equipment for the support of packet telemetry and telecommand

    NASA Technical Reports Server (NTRS)

    Hell, Wolfgang

    1994-01-01

    This paper describes ground equipment for packet telemetry and telecommand which has been recently developed by industry for the European Space Agency. The architectural concept for this type of equipment is outlined and the actual implementation is presented. Focus is put on issues related to cross support and telescience as far as they affect the design of the interfaces to the users of the services provided by the equipment and to the management entities in charge of equipment control and monitoring.

  7. Spin-orbit states of neutron wave packets

    NASA Astrophysics Data System (ADS)

    Nsofini, Joachim; Sarenac, Dusan; Wood, Christopher J.; Cory, David G.; Arif, Muhammad; Clark, Charles W.; Huber, Michael G.; Pushin, Dmitry A.

    2016-07-01

    We propose a method to prepare an entangled spin-orbit state between the spin and the orbital angular momenta of a neutron wave packet. This spin-orbit state is created by passing neutrons through the center of a quadrupole magnetic field, which provides a coupling between the spin and orbital degrees of freedom. A Ramsey-fringe-type measurement is suggested as a means of verifying the spin-orbit correlations.

  8. Lossless Compression of Data into Fixed-Length Packets

    NASA Technical Reports Server (NTRS)

    Kiely, Aaron B.; Klimesh, Matthew A.

    2009-01-01

    A computer program effects lossless compression of data samples from a one-dimensional source into fixed-length data packets. The software makes use of adaptive prediction: it exploits the data structure in such a way as to increase the efficiency of compression beyond that otherwise achievable. Adaptive linear filtering is used to predict each sample value based on past sample values. The difference between predicted and actual sample values is encoded using a Golomb code.

  9. Software For Management Of A Packet-Radio Network

    NASA Technical Reports Server (NTRS)

    Smyth, Patrick J.; Chauvin, Todd H.; Oliver, Gordon P.; Statman, Joseph I.

    1994-01-01

    Network-management software assists in planning, monitoring, and controlling resources of Datalink network. Packet-message network featuring time-division multiple access, frequency and spatial diversity, and dynamic tree-structured routing scheme. Developed for communication between central control station on ground and instrumented aircraft flying over test range. Aircraft derives navigational data from satellites of Global Positioning System, and primary function of Datalink network feeding GPS position data from participating aircraft into control center in real time.

  10. Attosecond Electron Wave-Packet Interference Observed by Transient Absorption

    SciTech Connect

    Holler, M.; Schapper, F.; Gallmann, L.; Keller, U.

    2011-03-25

    We perform attosecond time-resolved transient absorption spectroscopy around the first ionization threshold of helium and observe rapid oscillations of the absorption of the individual harmonics as a function of time delay with respect to a superimposed, moderately strong infrared laser field. The phase relation between the absorption modulation of individual harmonics gives direct evidence for the interference of transiently bound electronic wave packets as the mechanism behind the absorption modulation.

  11. Attosecond electron wave-packet interference observed by transient absorption.

    PubMed

    Holler, M; Schapper, F; Gallmann, L; Keller, U

    2011-03-25

    We perform attosecond time-resolved transient absorption spectroscopy around the first ionization threshold of helium and observe rapid oscillations of the absorption of the individual harmonics as a function of time delay with respect to a superimposed, moderately strong infrared laser field. The phase relation between the absorption modulation of individual harmonics gives direct evidence for the interference of transiently bound electronic wave packets as the mechanism behind the absorption modulation.

  12. Accelerating Airy-Gauss-Kummer localized wave packets

    NASA Astrophysics Data System (ADS)

    Zhong, Wei-Ping; Belić, Milivoj; Zhang, Yiqi; Huang, Tingwen

    2014-01-01

    A general approach to generating three-dimensional nondiffracting spatiotemporal solutions of the linear Schrödinger equation with an Airy-beam time-dependence is reported. A class of accelerating optical pulses with the structure of Airy-Gauss-Kummer vortex beams is obtained. Our results demonstrate that the optical field contributions to the Airy-Gauss-Kummer accelerating optical wave packets of the cylindrical symmetry can be characterized by the radial and angular mode numbers.

  13. SDN architecture for optical packet and circuit integrated networks

    NASA Astrophysics Data System (ADS)

    Furukawa, Hideaki; Miyazawa, Takaya

    2016-02-01

    We have been developing an optical packet and circuit integrated (OPCI) network, which realizes dynamic optical path, high-density packet multiplexing, and flexible wavelength resource allocation. In the OPCI networks, a best-effort service and a QoS-guaranteed service are provided by employing optical packet switching (OPS) and optical circuit switching (OCS) respectively, and users can select these services. Different wavelength resources are assigned for OPS and OCS links, and the amount of their wavelength resources are dynamically changed in accordance with the service usage conditions. To apply OPCI networks into wide-area (core/metro) networks, we have developed an OPCI node with a distributed control mechanism. Moreover, our OPCI node works with a centralized control mechanism as well as a distributed one. It is therefore possible to realize SDN-based OPCI networks, where resource requests and a centralized configuration are carried out. In this paper, we show our SDN architecture for an OPS system that configures mapping tables between IP addresses and optical packet addresses and switching tables according to the requests from multiple users via a web interface. While OpenFlow-based centralized control protocol is coming into widespread use especially for single-administrative, small-area (LAN/data-center) networks. Here, we also show an interworking mechanism between OpenFlow-based networks (OFNs) and the OPCI network for constructing a wide-area network, and a control method of wavelength resource selection to automatically transfer diversified flows from OFNs to the OPCI network.

  14. STS-90 Payload Specialist James Pawelczyk arrives at KSC

    NASA Technical Reports Server (NTRS)

    1998-01-01

    STS-90 Payload Specialist James Pawelczyk, Ph.D., tosses mission hats to his two children shortly after arrival at Kennedy Space Center's Shuttle Landing Facility. The crew of STS-90 arrived at KSC in preparation for their mission, scheduled for launch from KSC's Launch Pad 39B on April 16 at 2:19 p.m. EDT. The flight of Neurolab is scheduled to last nearly 17 days.

  15. Generalized Gaussian wave packet dynamics: Integrable and chaotic systems

    NASA Astrophysics Data System (ADS)

    Pal, Harinder; Vyas, Manan; Tomsovic, Steven

    2016-01-01

    The ultimate semiclassical wave packet propagation technique is a complex, time-dependent Wentzel-Kramers-Brillouin method known as generalized Gaussian wave packet dynamics (GGWPD). It requires overcoming many technical difficulties in order to be carried out fully in practice. In its place roughly twenty years ago, linearized wave packet dynamics was generalized to methods that include sets of off-center, real trajectories for both classically integrable and chaotic dynamical systems that completely capture the dynamical transport. The connections between those methods and GGWPD are developed in a way that enables a far more practical implementation of GGWPD. The generally complex saddle-point trajectories at its foundation are found using a multidimensional Newton-Raphson root search method that begins with the set of off-center, real trajectories. This is possible because there is a one-to-one correspondence. The neighboring trajectories associated with each off-center, real trajectory form a path that crosses a unique saddle; there are exceptions that are straightforward to identify. The method is applied to the kicked rotor to demonstrate the accuracy improvement as a function of ℏ that comes with using the saddle-point trajectories.

  16. Geometrical aspects in optical wave-packet dynamics.

    PubMed

    Onoda, Masaru; Murakami, Shuichi; Nagaosa, Naoto

    2006-12-01

    We construct a semiclassical theory for propagation of an optical wave packet in a nonconducting medium with a periodic structure of dielectric permittivity and magnetic permeability, i.e., a nonconducting photonic crystal. We employ a quantum-mechanical formalism in order to clarify its link to those of electronic systems. It involves the geometrical phase, i.e., Berry's phase, in a natural way, and describes an interplay between orbital motion and internal rotation. Based on the above theory, we discuss the geometrical aspects of the optical Hall effect. We also consider a reduction of the theory to a system without periodic structure and apply it to the transverse shift of an optical beam at an interface reflection or refraction. For a generic incident beam with an arbitrary polarization, an identical result for the transverse shift of each reflected or transmitted beam is given by the following different approaches: (i) analytic evaluation of wave-packet dynamics, (ii) total angular momentum (TAM) conservation for individual photons, and (iii) numerical simulation of wave-packet dynamics. It is consistent with a result by classical electrodynamics. This means that the TAM conservation for individual photons is already taken into account in wave optics, i.e., classical electrodynamics. Finally, we show an application of our theory to a two-dimensional photonic crystal, and propose an optimal design for the enhancement of the optical Hall effect in photonic crystals.

  17. Electronically nonadiabatic wave packet propagation using frozen Gaussian scattering

    NASA Astrophysics Data System (ADS)

    Kondorskiy, Alexey D.; Nanbu, Shinkoh

    2015-09-01

    We present an approach, which allows to employ the adiabatic wave packet propagation technique and semiclassical theory to treat the nonadiabatic processes by using trajectory hopping. The approach developed generates a bunch of hopping trajectories and gives all additional information to incorporate the effect of nonadiabatic coupling into the wave packet dynamics. This provides an interface between a general adiabatic frozen Gaussian wave packet propagation method and the trajectory surface hopping technique. The basic idea suggested in [A. D. Kondorskiy and H. Nakamura, J. Chem. Phys. 120, 8937 (2004)] is revisited and complemented in the present work by the elaboration of efficient numerical algorithms. We combine our approach with the adiabatic Herman-Kluk frozen Gaussian approximation. The efficiency and accuracy of the resulting method is demonstrated by applying it to popular benchmark model systems including three Tully's models and 24D model of pyrazine. It is shown that photoabsorption spectrum is successfully reproduced by using a few hundreds of trajectories. We employ the compact finite difference Hessian update scheme to consider feasibility of the ab initio "on-the-fly" simulations. It is found that this technique allows us to obtain the reliable final results using several Hessian matrix calculations per trajectory.

  18. Wave packet spreading and localization in electron-nuclear scattering

    NASA Astrophysics Data System (ADS)

    Grabowski, Paul E.; Markmann, Andreas; Morozov, Igor V.; Valuev, Ilya A.; Fichtl, Christopher A.; Richards, David F.; Batista, Victor S.; Graziani, Frank R.; Murillo, Michael S.

    2013-06-01

    The wave packet molecular dynamics (WPMD) method provides a variational approximation to the solution of the time-dependent Schrödinger equation. Its application in the field of high-temperature dense plasmas has yielded diverging electron width (spreading), which results in diminishing electron-nuclear interactions. Electron spreading has previously been ascribed to a shortcoming of the WPMD method and has been counteracted by various heuristic additions to the models used. We employ more accurate methods to determine if spreading continues to be predicted by them and how WPMD can be improved. A scattering process involving a single dynamic electron interacting with a periodic array of statically screened protons is used as a model problem for comparison. We compare the numerically exact split operator Fourier transform method, the Wigner trajectory method, and the time-dependent variational principle (TDVP). Within the framework of the TDVP, we use the standard variational form of WPMD, the single Gaussian wave packet (WP), as well as a sum of Gaussian WPs, as in the split WP method. Wave packet spreading is predicted by all methods, so it is not the source of the unphysical diminishing of electron-nuclear interactions in WPMD at high temperatures. Instead, the Gaussian WP's inability to correctly reproduce breakup of the electron's probability density into localized density near the protons is responsible for the deviation from more accurate predictions. Extensions of WPMD must include a mechanism for breakup to occur in order to yield dynamics that lead to accurate electron densities.

  19. Generalized Gaussian wave packet dynamics: Integrable and chaotic systems.

    PubMed

    Pal, Harinder; Vyas, Manan; Tomsovic, Steven

    2016-01-01

    The ultimate semiclassical wave packet propagation technique is a complex, time-dependent Wentzel-Kramers-Brillouin method known as generalized Gaussian wave packet dynamics (GGWPD). It requires overcoming many technical difficulties in order to be carried out fully in practice. In its place roughly twenty years ago, linearized wave packet dynamics was generalized to methods that include sets of off-center, real trajectories for both classically integrable and chaotic dynamical systems that completely capture the dynamical transport. The connections between those methods and GGWPD are developed in a way that enables a far more practical implementation of GGWPD. The generally complex saddle-point trajectories at its foundation are found using a multidimensional Newton-Raphson root search method that begins with the set of off-center, real trajectories. This is possible because there is a one-to-one correspondence. The neighboring trajectories associated with each off-center, real trajectory form a path that crosses a unique saddle; there are exceptions that are straightforward to identify. The method is applied to the kicked rotor to demonstrate the accuracy improvement as a function of ℏ that comes with using the saddle-point trajectories.

  20. The performance analysis of linux networking - packet receiving

    SciTech Connect

    Wu, Wenji; Crawford, Matt; Bowden, Mark; /Fermilab

    2006-11-01

    The computing models for High-Energy Physics experiments are becoming ever more globally distributed and grid-based, both for technical reasons (e.g., to place computational and data resources near each other and the demand) and for strategic reasons (e.g., to leverage equipment investments). To support such computing models, the network and end systems, computing and storage, face unprecedented challenges. One of the biggest challenges is to transfer scientific data sets--now in the multi-petabyte (10{sup 15} bytes) range and expected to grow to exabytes within a decade--reliably and efficiently among facilities and computation centers scattered around the world. Both the network and end systems should be able to provide the capabilities to support high bandwidth, sustained, end-to-end data transmission. Recent trends in technology are showing that although the raw transmission speeds used in networks are increasing rapidly, the rate of advancement of microprocessor technology has slowed down. Therefore, network protocol-processing overheads have risen sharply in comparison with the time spent in packet transmission, resulting in degraded throughput for networked applications. More and more, it is the network end system, instead of the network, that is responsible for degraded performance of network applications. In this paper, the Linux system's packet receive process is studied from NIC to application. We develop a mathematical model to characterize the Linux packet receiving process. Key factors that affect Linux systems network performance are analyzed.

  1. Electronically nonadiabatic wave packet propagation using frozen Gaussian scattering

    SciTech Connect

    Kondorskiy, Alexey D.; Nanbu, Shinkoh

    2015-09-21

    We present an approach, which allows to employ the adiabatic wave packet propagation technique and semiclassical theory to treat the nonadiabatic processes by using trajectory hopping. The approach developed generates a bunch of hopping trajectories and gives all additional information to incorporate the effect of nonadiabatic coupling into the wave packet dynamics. This provides an interface between a general adiabatic frozen Gaussian wave packet propagation method and the trajectory surface hopping technique. The basic idea suggested in [A. D. Kondorskiy and H. Nakamura, J. Chem. Phys. 120, 8937 (2004)] is revisited and complemented in the present work by the elaboration of efficient numerical algorithms. We combine our approach with the adiabatic Herman-Kluk frozen Gaussian approximation. The efficiency and accuracy of the resulting method is demonstrated by applying it to popular benchmark model systems including three Tully’s models and 24D model of pyrazine. It is shown that photoabsorption spectrum is successfully reproduced by using a few hundreds of trajectories. We employ the compact finite difference Hessian update scheme to consider feasibility of the ab initio “on-the-fly” simulations. It is found that this technique allows us to obtain the reliable final results using several Hessian matrix calculations per trajectory.

  2. Aggregates, broccoli and cauliflower

    NASA Astrophysics Data System (ADS)

    Grey, Francois; Kjems, Jørgen K.

    1989-09-01

    Naturally grown structures with fractal characters like broccoli and cauliflower are discussed and compared with DLA-type aggregates. It is suggested that the branching density can be used to characterize the growth process and an experimental method to determine this parameter is proposed.

  3. Estimating Controller Intervention Probabilities for Optimized Profile Descent Arrivals

    NASA Technical Reports Server (NTRS)

    Meyn, Larry A.; Erzberger, Heinz; Huynh, Phu V.

    2011-01-01

    Simulations of arrival traffic at Dallas/Fort-Worth and Denver airports were conducted to evaluate incorporating scheduling and separation constraints into advisories that define continuous descent approaches. The goal was to reduce the number of controller interventions required to ensure flights maintain minimum separation distances of 5 nmi horizontally and 1000 ft vertically. It was shown that simply incorporating arrival meter fix crossing-time constraints into the advisory generation could eliminate over half of the all predicted separation violations and more than 80% of the predicted violations between two arrival flights. Predicted separation violations between arrivals and non-arrivals were 32% of all predicted separation violations at Denver and 41% at Dallas/Fort-Worth. A probabilistic analysis of meter fix crossing-time errors is included which shows that some controller interventions will still be required even when the predicted crossing-times of the advisories are set to add a 1 or 2 nmi buffer above the minimum in-trail separation of 5 nmi. The 2 nmi buffer was shown to increase average flight delays by up to 30 sec when compared to the 1 nmi buffer, but it only resulted in a maximum decrease in average arrival throughput of one flight per hour.

  4. Can we image complex structures with first-arrival traveltime

    SciTech Connect

    Geoltrain, S.; Brac, J. . PSI Research Consortium)

    1993-04-01

    The authors experienced difficulties when attempting to perform seismic imaging in complex velocity fields using prestack Kirchhoff depth migration in conjunction with traveltimes computed by finite-differencing the eikonal equation. The problem arose not because of intrinsic limitations of kirchhoff migration, but rather from the failure of finite-differencing to compute traveltimes representative of the energetic part of the wavefield. Further analysis showed that the first arrival is most often associated with a marginally energetic event wherever subsequent arrivals exist. The consequence is that energetic seismic events are imaged with a kinematically incorrect operator and turn out mispositioned at depth. They therefore recommend that first-arrival traveltime fields, such as those computed by finite-differencing the eikonal equation, be used in Kirchhoff migration only with great care when the velocity field hosts multiple transmitted arrivals; such a situation is typically met where geological structure creates strong and localized velocity hetero-geneities, which partition the incident and reflected wavefields into multiple arrivals; in such an instance, imaging cannot be strictly considered a kinematic process, as it must be performed with explicit reference to the relative amplitudes of multiple arrivals.

  5. Biomimetic direction of arrival estimation for resolving front-back confusions in hearing aids

    PubMed Central

    Archer-Boyd, Alan W.; Whitmer, William M.; Brimijoin, W. Owen; Soraghan, John J.

    2015-01-01

    Sound sources at the same angle in front or behind a two-microphone array (e.g., bilateral hearing aids) produce the same time delay and two estimates for the direction of arrival: A front-back confusion. The auditory system can resolve this issue using head movements. To resolve front-back confusion for hearing-aid algorithms, head movement was measured using an inertial sensor. Successive time-delay estimates between the microphones are shifted clockwise and counterclockwise by the head movement between estimates and aggregated in two histograms. The histogram with the largest peak after multiple estimates predicted the correct hemifield for the source, eliminating the front-back confusions. PMID:25994734

  6. Efficient algorithms for optimal arrival scheduling and air traffic flow management

    NASA Astrophysics Data System (ADS)

    Saraf, Aditya

    The research presented in this dissertation is motivated by the need for new, efficient algorithms for the solution of two important problems currently faced by the air-traffic control community: (i) optimal scheduling of aircraft arrivals at congested airports, and (ii) optimal National Airspace System (NAS) wide traffic flow management. In the first part of this dissertation, we present an optimal airport arrival scheduling algorithm, which works within a hierarchical scheduling structure. This structure consists of schedulers at multiple points along the arrival-route. Schedulers are linked through acceptance-rate constraints, which are passed up from downstream metering-points. The innovation in this scheduling algorithm is that these constraints are computed by using an Eulerian model-based optimization scheme. This rate computation removes inefficiencies introduced in the schedule through ad hoc acceptance-rate computations. The scheduling process at every metering-point uses its optimal acceptance-rate as a constraint and computes optimal arrival sequences by using a combinatorial search-algorithm. We test this algorithm in a dynamic air-traffic environment, which can be customized to emulate different arrival scenarios. In the second part of this dissertation, we introduce a novel two-level control system for optimal traffic-flow management. The outer-level control module of this two-level control system generates an Eulerian-model of the NAS by aggregating aircraft into interconnected control-volumes. Using this Eulerian model of the airspace, control strategies like Model Predictive Control are applied to find the optimal inflow and outflow commands for each control-volume so that efficient flows are achieved in the NAS. Each control-volume has its separate inner-level control-module. The inner-level control-module takes in the optimal inflow and outflow commands generated by the outer control-module as reference inputs and uses hybrid aircraft models to

  7. Rydberg Wave Packets and Half-Cycle Electromagnetic Pulses

    NASA Astrophysics Data System (ADS)

    Raman, Chandra S.

    1998-05-01

    This dissertation summarizes an examination of the dynamics of atomic Rydberg wave packets with coherent pulses of THz electromagnetic radiation consisting of less than a single cycle of the electric field. The bulk of the energy is contained in just a half-cycle. Previous work ( R. Jones, D. You, and P. Bucksbaum, ``Ionization of Rydberg atoms by subpicosecond half-cycle electromagnetic pulses,'' Phys. Rev. Lett.), vol. 70, 1993. had shown how these half-cycle pulses can be used to ionize the highly excited states of an atom, and that a classical view of electronic motion in the atom explains the ionization mechanism. To further probe the boundary between classical trajectories and quantum mechanics, in this work I investigate dynamical combinations of Rydberg states, or Rydberg wave packets, and how they ionize under the influence of a half-cycle electromagnetic pulse. With time-domain techniques I am able to extract the dynamics of the wave packet from the ionization rate, and to observe wave packet motion in both the electronic radial ( C. Raman, C. Conover, C. Sukenik, and P. Bucksbaum, ``Ionization of Rydberg wavepackets by sub-picosecond half-cycle electromagnetic pulses,'' Phys. Rev. Lett.), vol. 76, 1996.and angular ( C. Raman, T. Weinacht, and P. Bucksbaum, ``Stark wavepackets viewed with half cycle pulses.'' Phys. Rev. A), vol. 55, No. 6, 1997. coordinates. This is the first time a wavepacket technique has been used to view electron motion everywhere on its trajectory, and not just at the nucleus. This is the principal feature of half-cycle pulse ionization. Semiclassical ideas of ionization in conjunction with quantum descriptions of the wave packet, are capable of reproducing the main trends in the data, and in the absence of a rigorous model I rely on these. Experiments of this nature provide examples of the ongoing effort to use the coherent properties of radiation to control electronic motion in an atom, as well as to probe the boundaries between

  8. Shear wave arrival time estimates correlate with local speckle pattern.

    PubMed

    Mcaleavey, Stephen A; Osapoetra, Laurentius O; Langdon, Jonathan

    2015-12-01

    We present simulation and phantom studies demonstrating a strong correlation between errors in shear wave arrival time estimates and the lateral position of the local speckle pattern in targets with fully developed speckle. We hypothesize that the observed arrival time variations are largely due to the underlying speckle pattern, and call the effect speckle bias. Arrival time estimation is a key step in quantitative shear wave elastography, performed by tracking tissue motion via cross-correlation of RF ultrasound echoes or similar methods. Variations in scatterer strength and interference of echoes from scatterers within the tracking beam result in an echo that does not necessarily describe the average motion within the beam, but one favoring areas of constructive interference and strong scattering. A swept-receive image, formed by fixing the transmit beam and sweeping the receive aperture over the region of interest, is used to estimate the local speckle pattern. Metrics for the lateral position of the speckle are found to correlate strongly (r > 0.7) with the estimated shear wave arrival times both in simulations and in phantoms. Lateral weighting of the swept-receive pattern improved the correlation between arrival time estimates and speckle position. The simulations indicate that high RF echo correlation does not equate to an accurate shear wave arrival time estimate-a high correlation coefficient indicates that motion is being tracked with high precision, but the location tracked is uncertain within the tracking beam width. The presence of a strong on-axis speckle is seen to imply high RF correlation and low bias. The converse does not appear to be true-highly correlated RF echoes can still produce biased arrival time estimates. The shear wave arrival time bias is relatively stable with variations in shear wave amplitude and sign (-20 μm to 20 μm simulated) compared with the variation with different speckle realizations obtained along a given tracking

  9. Implementation of a Data Packet Generator Using Pattern Matching for Wearable ECG Monitoring Systems

    PubMed Central

    Noh, Yun Hong; Jeong, Do Un

    2014-01-01

    In this paper, a packet generator using a pattern matching algorithm for real-time abnormal heartbeat detection is proposed. The packet generator creates a very small data packet which conveys sufficient crucial information for health condition analysis. The data packet envelopes real time ECG signals and transmits them to a smartphone via Bluetooth. An Android application was developed specifically to decode the packet and extract ECG information for health condition analysis. Several graphical presentations are displayed and shown on the smartphone. We evaluate the performance of abnormal heartbeat detection accuracy using the MIT/BIH Arrhythmia Database and real time experiments. The experimental result confirm our finding that abnormal heart beat detection is practically possible. We also performed data compression ratio and signal restoration performance evaluations to establish the usefulness of the proposed packet generator and the results were excellent. PMID:25029280

  10. Implementation of a data packet generator using pattern matching for wearable ECG monitoring systems.

    PubMed

    Noh, Yun Hong; Jeong, Do Un

    2014-01-01

    In this paper, a packet generator using a pattern matching algorithm for real-time abnormal heartbeat detection is proposed. The packet generator creates a very small data packet which conveys sufficient crucial information for health condition analysis. The data packet envelopes real time ECG signals and transmits them to a smartphone via Bluetooth. An Android application was developed specifically to decode the packet and extract ECG information for health condition analysis. Several graphical presentations are displayed and shown on the smartphone. We evaluate the performance of abnormal heartbeat detection accuracy using the MIT/BIH Arrhythmia Database and real time experiments. The experimental result confirm our finding that abnormal heart beat detection is practically possible. We also performed data compression ratio and signal restoration performance evaluations to establish the usefulness of the proposed packet generator and the results were excellent. PMID:25029280

  11. Observation of ICRF (ion cyclotron range of frequencies) wave-packet propagation in a tokamak plasma

    SciTech Connect

    Greene, G.J.; Gould, R.W.

    1987-11-01

    Experimental observation of ICRF wave-packet propagation in a tokamak plasma is reported. Studies were carried out in the Caltech Research Tokamak in a pure hydrogen plasma and in a regime where fast-wave damping was sufficiently small to permit multiple toroidal transits of the wave-packet. Waves were launched by exciting a small loop antenna with a short burst of rf current and were detected with shielded magnetic probes. Probe scans revealed a large increase in wave-packet amplitude at smaller minor radii, and the packet velocity was found to be independent of radial position. Measurement of the packet transit time yielded direct information about the wave group velocity. Packet velocity was investigated as a function of the fundamental excitation frequency, plasma density, and toroidal magnetic field. Results are compared with the predictions of a cold plasma model which includes a vacuum layer at the edge. 24 refs., 8 figs.

  12. PacketLib: A C++ Library for Scientific Satellite Telemetry Applications

    NASA Astrophysics Data System (ADS)

    Bulgarelli, A.; Gianotti, F.; Trifoglio, M.

    PacketLib is a C++ open-source software library for writing applications which deal with satellite telemetry source packets, provided that the packets are compliant with the CCSDS Telemetry and Telecommand Standards. The library is being used within the Italian Space Agency (ASI) mission AGILE for simulation, graphical display, processing and decoding of the telemetry generated by the Test Equipment (TE) of two AGILE detectors. From an input stream of bytes, the library is able to recognize automatically the source packets (described by a simple configuration file), and provides a simple access to each packet field by means of an object oriented interface. In the same way the library writes source packets to output stream. Various types of input and output streams are abstracted by a software layer.

  13. Assessment of the performance of the inter-arrival time algorithm to identify ice shattering artifacts in cloud particle probe measurements

    NASA Astrophysics Data System (ADS)

    Korolev, A.; Field, P. R.

    2015-02-01

    Shattering presents a serious obstacle to current airborne in situ methods of characterizing the microphysical properties of ice clouds. Small shattered fragments result from the impact of natural ice crystals with the forward parts of aircraft-mounted measurement probes. The presence of these shattered fragments may result in a significant overestimation of the measured concentration of small ice crystals, contaminating the measurement of the ice particle size distribution (PSD). One method of identifying shattered particles is to use an inter-arrival time algorithm. This method is based on the assumption that shattered fragments form spatial clusters that have short inter-arrival times between particles, relative to natural particles, when they pass through the sample volume of the probe. The inter-arrival time algorithm is a successful technique for the classification of shattering artifacts and natural particles. This study assesses the limitations and efficiency of the inter-arrival time algorithm. The analysis has been performed using simultaneous measurements of two-dimensional (2-D) optical array probes with the standard and antishattering "K-tips" collected during the Airborne Icing Instrumentation Experiment (AIIE). It is shown that the efficiency of the algorithm depends on ice particle size, concentration and habit. Additional numerical simulations indicate that the effectiveness of the inter-arrival time algorithm to eliminate shattering artifacts can be significantly restricted in some cases. Improvements to the inter-arrival time algorithm are discussed. It is demonstrated that blind application of the inter-arrival time algorithm cannot filter out all shattered aggregates. To mitigate against the effects of shattering, the inter-arrival time algorithm should be used together with other means, such as antishattering tips and specially designed algorithms for segregation of shattered artifacts and natural particles.

  14. Proteins aggregation and human diseases

    NASA Astrophysics Data System (ADS)

    Hu, Chin-Kun

    2015-04-01

    Many human diseases and the death of most supercentenarians are related to protein aggregation. Neurodegenerative diseases include Alzheimer's disease (AD), Huntington's disease (HD), Parkinson's disease (PD), frontotemporallobar degeneration, etc. Such diseases are due to progressive loss of structure or function of neurons caused by protein aggregation. For example, AD is considered to be related to aggregation of Aβ40 (peptide with 40 amino acids) and Aβ42 (peptide with 42 amino acids) and HD is considered to be related to aggregation of polyQ (polyglutamine) peptides. In this paper, we briefly review our recent discovery of key factors for protein aggregation. We used a lattice model to study the aggregation rates of proteins and found that the probability for a protein sequence to appear in the conformation of the aggregated state can be used to determine the temperature at which proteins can aggregate most quickly. We used molecular dynamics and simple models of polymer chains to study relaxation and aggregation of proteins under various conditions and found that when the bending-angle dependent and torsion-angle dependent interactions are zero or very small, then protein chains tend to aggregate at lower temperatures. All atom models were used to identify a key peptide chain for the aggregation of insulin chains and to find that two polyQ chains prefer anti-parallel conformation. It is pointed out that in many cases, protein aggregation does not result from protein mis-folding. A potential drug from Chinese medicine was found for Alzheimer's disease.

  15. Safety management of Ethernet broadband access based on VLAN aggregation

    NASA Astrophysics Data System (ADS)

    Wang, Li

    2004-04-01

    With broadband access network development, the Ethernet technology is more and more applied access network now. It is different from the private network -LAN. The differences lie in four points: customer management, safety management, service management and count-fee management. This paper mainly discusses the safety management related questions. Safety management means that the access network must secure the customer data safety, isolate the broad message which brings the customer private information, such as ARP, DHCP, and protect key equipment from attack. Virtue LAN (VLAN) technology can restrict network broadcast flow. We can config each customer port with a VLAN, so each customer is isolated with others. The IP address bound with VLAN ID can be routed rightly. But this technology brings another question: IP address shortage. VLAN aggregation technology can solve this problem well. Such a mechanism provides several advantages over traditional IPv4 addressing architectures employed in large switched LANs today. With VLAN aggregation technology, we introduce the notion of sub-VLANs and super-VLANs, a much more optimal approach to IP addressing can be realized. This paper will expatiate the VLAN aggregation model and its implementation in Ethernet access network. It is obvious that the customers in different sub-VLANs can not communication to each other because the ARP packet is isolated. Proxy ARP can enable the communication among them. This paper will also expatiate the proxy ARP model and its implementation in Ethernet access network.

  16. Selection of ionization paths of K2 on superfluid helium droplets by wave packet interference

    NASA Astrophysics Data System (ADS)

    Hild, Marek Bastian; Dufour, Adrien; Achazi, Georg; Patas, Alexander; Scheier, Paul; Lindinger, Albrecht

    2016-08-01

    We report on the control of wave packet dynamics for the ionization of K2 attached to the surface of superfluid helium droplets. The superfluid helium matrix acts as a heat sink and reduces the coherence time of molecular processes by dissipation. We use tailor-shaped pulses in order to activate or inhibit different ionization paths by constructive or destructive wave packet interference. A drastic change of the wave packet dynamics is observed by shifting the phase between the exciting sub pulses.

  17. Encoding and Decoding Information in High-n Circular Wave Packets

    SciTech Connect

    Yoshida, S.; Reinhold, Carlos O; Burgdorfer, J.; Wyker, B.; Dunning, F. B.

    2010-01-01

    We demonstrate theoretically and experimentally the extraction of detailed information on the density matrix of very-high-n(> 300) near-circular Rydberg wave packets through Fourier analysis of the quantum beat and quantum revival signal. The remarkably long coherence times associated with circular wave packets facilitate the preservation and read-out of information encoded in this matrix. We illustrate the power of the method by determining the angular localization of the components of a wave packet.

  18. Packet Randomized Experiments for Eliminating Classes of Confounders

    PubMed Central

    Pavela, Greg; Wiener, Howard; Fontaine, Kevin R.; Fields, David A.; Voss, Jameson D.; Allison, David B.

    2014-01-01

    Background Although randomization is considered essential for causal inference, it is often not possible to randomize in nutrition and obesity research. To address this, we develop a framework for an experimental design—packet randomized experiments (PREs), which improves causal inferences when randomization on a single treatment variable is not possible. This situation arises when subjects are randomly assigned to a condition (such as a new roommate) which varies in one characteristic of interest (such as weight), but also varies across many others. There has been no general discussion of this experimental design, including its strengths, limitations, and statistical properties. As such, researchers are left to develop and apply PREs on an ad hoc basis, limiting its potential to improve causal inferences among nutrition and obesity researchers. Methods We introduce PREs as an intermediary design between randomized controlled trials and observational studies. We review previous research that used the PRE design and describe its application in obesity-related research, including random roommate assignments, heterochronic parabiosis, and the quasi-random assignment of subjects to geographic areas. We then provide a statistical framework to control for potential packet-level confounders not accounted for by randomization. Results PREs have successfully been used to improve causal estimates of the effect of roommates, altitude, and breastfeeding on weight outcomes. When certain assumptions are met, PREs can asymptotically control for packet-level characteristics. This has the potential to statistically estimate the effect of a single treatment even when randomization to a single treatment did not occur. Conclusions Applying PREs to obesity-related research will improve decisions about clinical, public health, and policy actions insofar as it offers researchers new insight into cause and effect relationships among variables. PMID:25444088

  19. Design Considerations for a New Terminal Area Arrival Scheduler

    NASA Technical Reports Server (NTRS)

    Thipphavong, Jane; Mulfinger, Daniel

    2010-01-01

    Design of a terminal area arrival scheduler depends on the interrelationship between throughput, delay and controller intervention. The main contribution of this paper is an analysis of the above interdependence for several stochastic behaviors of expected system performance distributions in the aircraft s time of arrival at the meter fix and runway. Results of this analysis serve to guide the scheduler design choices for key control variables. Two types of variables are analyzed, separation buffers and terminal delay margins. The choice for these decision variables was tested using sensitivity analysis. Analysis suggests that it is best to set the separation buffer at the meter fix to its minimum and adjust the runway buffer to attain the desired system performance. Delay margin was found to have the least effect. These results help characterize the variables most influential in the scheduling operations of terminal area arrivals.

  20. Prediction of the shock arrival time with SEP observations

    NASA Astrophysics Data System (ADS)

    Qin, G.; Zhang, M.; Rassoul, H. K.

    2009-09-01

    Real-time prediction of the arrival times at Earth of shocks is very important for space weather research. Recently, various models for shock propagation are used to forecast the shock arriving times (SATs) with information of initial coronal shock and flare from near real-time radio and X-ray data. In this paper, we add the use of solar energetic particles (SEP) observation to improve the shock arrival time (SAT) prediction. High-energy SEPs originating from flares move to the Earth much faster than the shocks related to the same flares. We develop an SAT prediction model by combining a well-known shock propagation model, STOA, and the analysis of SEPs detected at Earth. We demonstrate that the SAT predictions are improved by the new model with the help of 38-53 keV electron SEP observations. In particular, the correct prediction to false alarm ratio is improved significantly.

  1. LETTER: Arrival time statistics in global disease spread

    NASA Astrophysics Data System (ADS)

    Gautreau, Aurélien; Barrat, Alain; Barthélemy, Marc

    2007-09-01

    Metapopulation models describing cities with different populations coupled by the travel of individuals are of great importance in the understanding of disease spread on a large scale. An important example is the Rvachev Longini model which is widely used in computational epidemiology. Few analytical results are, however, available and, in particular, little is known about paths followed by epidemics and disease arrival times. We study the arrival time of a disease in a city as a function of the starting seed of the epidemics. We propose an analytical ansatz, test it in the case of a spread on the worldwide air-transportation network, and show that it predicts accurately the arrival order of a disease in worldwide cities.

  2. Time delay of wave packets during their tunnelling through a quantum diode

    SciTech Connect

    Ivanov, N A; Skalozub, V V

    2014-04-28

    A modified saddle-point method is used to investigate the process of propagation of a wave packet through a quantum diode. A scattering matrix is constructed for the structure in question. The case of tunnelling of a packet with a Gaussian envelope through the diode is considered in detail. The time delay and the shape of the wave packet transmitted are calculated. The dependence of the delay time on the characteristics of the input packet and the internal characteristics of the quantum diode is studied. Possible applications of the results obtained are discussed. (laser applications and other topics in quantum electronics)

  3. Wave-packet dynamics on Chern-band lattices in a trap

    NASA Astrophysics Data System (ADS)

    Roy, Sthitadhi; Grushin, Adolfo G.; Moessner, Roderich; Haque, Masudul

    2015-12-01

    The experimental realization of lattices with Chern bands in ultracold-atom and photonic systems has motivated the study of time-dependent phenomena, such as spatial propagation, in lattices with nontrivial topology. We study the dynamics of Gaussian wave packets on the Haldane honeycomb Chern-band lattice model, in the presence of a harmonic trap. We focus on the transverse response to a force, which is due partly to the Berry curvature and partly to the transverse component of the energy band curvature. We evaluate the accuracy of a semiclassical description, which treats the wave packet as a point particle in both real and momentum space, in reproducing the motion of a realistic wave packet with finite extent. We find that, in order to accurately capture the wave-packet dynamics, the extent of the wave packet in momentum space needs to be taken into account: The dynamics is sensitive to the interplay of band dispersion and Berry curvature over the finite region of momentum (reciprocal) space where the wave packet has support. Moreover, if the wave packet is prepared with a finite initial momentum, the semiclassical analysis reproduces its motion as long as it has a large overlap with the eigenstates of a single band. The semiclassical description generally improves with increasing real-space size of the wave packet, as long as the external conditions (e.g., external force) remain uniform throughout the spatial extent of the wave packet.

  4. Generation of optical pulse packet using a fiber stacker for time fiducial applications

    NASA Astrophysics Data System (ADS)

    Lin, Honghuan; Wang, Jianjun; Huang, Zhihua; Li, Qi; Xu, Lixin; Tang, Xuan; Li, Chengyu; Guo, Chao; Zhao, Pengfei; Jing, Feng

    2016-08-01

    We present the concept of multicolor optical pulse packet generation based on modified fiber stackers featured with reflection geometries. Infrared radiation, visible and ultraviolet time fiducials were obtained by the amplification and frequency-conversion of the pulse packet generated in this fiber stacker. Application for the inertial confinement fusion (ICF) experiment diagnosis with time fiducials was demonstrated. With featured reflection geometries, the shaped packet pulses with uniform sub-pulse polarization states in a temporal window of ns range were generated in the fiber stacker. The design greatly simplifies the packet pulse generation for time fiducial and could be used for laser-driven ICF experimental diagnosis.

  5. Time behavior of a Gaussian wave packet accompanying the generalized coherent state for the inverted oscillator

    NASA Astrophysics Data System (ADS)

    Maamache, Mustapha; Bouguerra, Yacine; Choi, Jeong Ryeol

    2016-06-01

    A Gaussian wave packet of the inverted oscillator is investigated using the invariant operator method together with the unitary transformation method. A simple wave packet directly derived from the eigenstates of the invariant operator of the system corresponds to a plane wave that is fully delocalized. However, we can construct a weighted wave packet in terms of such plane waves, which corresponds to a Gaussian wave. This wave packet is associated with the generalized coherent state, which can be crucially utilized for investigating the classical limit of quantum wave mechanics. Various quantum properties of the system, such as fluctuations of the canonical variables, the uncertainty product, and the motion of the wave packet or quantum particle, are analyzed by means of this wave packet. We have confirmed that the time behavior of such a wave packet is very similar to the counterpart classical state. The wave packet runs away from the origin in the positive or negative direction in the 1D coordinate depending on the condition of the initial state. We have confirmed that this wave packet not only moves acceleratively but also spreads out during its propagation.

  6. Self-organising continuous attractor networks with multiple activity packets, and the representation of space.

    PubMed

    Stringer, S M; Rolls, E T; Trappenberg, T P

    2004-01-01

    'Continuous attractor' neural networks can maintain a localised packet of neuronal activity representing the current state of an agent in a continuous space without external sensory input. In applications such as the representation of head direction or location in the environment, only one packet of activity is needed. For some spatial computations a number of different locations, each with its own features, must be held in memory. We extend previous approaches to continuous attractor networks (in which one packet of activity is maintained active) by showing that a single continuous attractor network can maintain multiple packets of activity simultaneously, if each packet is in a different state space or map. We also show how such a network could by learning self-organise to enable the packets in each space to be moved continuously in that space by idiothetic (motion) inputs. We show how such multi-packet continuous attractor networks could be used to maintain different types of feature (such as form vs colour) simultaneously active in the correct location in a spatial representation. We also show how high-order synapses can improve the performance of these networks, and how the location of a packet could be read by motor networks. The multiple packet continuous attractor networks described here may be used for spatial representations in brain areas such as the parietal cortex and hippocampus.

  7. Real-time video transmission over a fast packet-switched network

    NASA Astrophysics Data System (ADS)

    Moorhead, Robert J.; Ma, Joong S.; Gonzales, Cesar A.

    1989-04-01

    Realtime transmission of packetized video is a relatively new but important area of research since tomorrow's networks will likely be based on a common fast packet-switching technology, replacing today's heterogeneous networks which are mixtures of circuit-switched and packet-switched networks dedicated for synchronous and asynchronous applications respectively. Unlike fixed bandwidth transmission channels, packet-switched networks can accommodate the bursty and highly variable rate of compressed motion video yet keep a constant level of image quality. Potential applications include motion video databases, video teleconferencing, and broadcasting over private networks. Unfortunately, traditional video-compression techniques which are applicable to synchronous, fixed bandwidth channels--cannot be applied in this new environment without substantial revisions that take into account the statistical nature of packet data transmission. Independent of their topology, fast packet-switched networks present unique challenges to the coding of motion video; one cannot simply divorce the coding of the source from the characteristics of the channel. The potential for loss of data integrity due to packet losses and transmission errors must be taken into account. The problem of re-synchronization must also be addressed since packet-switched networks are asynchronous by nature. In this paper, we evaluate image coding techniques for motion video in view of the constraints imposed by the packetized medium.

  8. The application study of wavelet packet transformation in the de-noising of dynamic EEG data.

    PubMed

    Li, Yifeng; Zhang, Lihui; Li, Baohui; Wei, Xiaoyang; Yan, Guiding; Geng, Xichen; Jin, Zhao; Xu, Yan; Wang, Haixia; Liu, Xiaoyan; Lin, Rong; Wang, Quan

    2015-01-01

    This paper briefly describes the basic principle of wavelet packet analysis, and on this basis introduces the general principle of wavelet packet transformation for signal den-noising. The dynamic EEG data under +Gz acceleration is made a de-noising treatment by using wavelet packet transformation, and the de-noising effects with different thresholds are made a comparison. The study verifies the validity and application value of wavelet packet threshold method for the de-noising of dynamic EEG data under +Gz acceleration. PMID:26405863

  9. Field structure of collapsing wave packets in 3D strong Langmuir turbulence

    NASA Technical Reports Server (NTRS)

    Newman, D. L.; Robinson, P. A.; Goldman, M. V.

    1989-01-01

    A simple model is constructed for the electric fields in the collapsing wave packets found in 3D simulations of driven and damped isotropic strong Langmuir turbulence. This model, based on a spherical-harmonic decomposition of the electrostatic potential, accounts for the distribution of wave-packet shapes observed in the simulations, particularly the predominance of oblate wave packets. In contrast with predictions for undamped and undriven subsonic collapse of scalar fields, oblate vector-field wave packets do not flatten during collapse but, instead, remain approximately self-similar and rigid.

  10. Nonlinear single Compton scattering of an electron wave packet

    NASA Astrophysics Data System (ADS)

    Angioi, A.; Mackenroth, F.; Di Piazza, A.

    2016-05-01

    Nonlinear single Compton scattering has been thoroughly investigated in the literature under the assumption that the electron initially has a definite momentum. Here, we study a more general initial state and consider the electron as a wave packet. In particular, we investigate the energy spectrum of the emitted radiation and show that, in typical experimental situations, some features of the spectra shown in previous works are almost completely washed out. Moreover, we show that, at comparable relative uncertainties, the one in the momentum of the incoming electron has a larger impact on the photon spectra at a fixed observation direction than the one on the laser frequency.

  11. Electroencephalography data analysis by using discrete wavelet packet transform

    NASA Astrophysics Data System (ADS)

    Karim, Samsul Ariffin Abdul; Ismail, Mohd Tahir; Hasan, Mohammad Khatim; Sulaiman, Jumat; Muthuvalu, Mohana Sundaram; Janier Josefina, B.

    2015-05-01

    Electroencephalography (EEG) is the electrical activity generated by the movement of neurons in the brain. It is categorized into delta waves, theta, alpha, beta and gamma. These waves exist in a different frequency band. This paper is a continuation of our previous research. EEG data will be decomposed using Discrete Wavelet Packet Transform (DWPT). Daubechies wavelets 10 (D10) will be used as the basic functions for research purposes. From the main results, it is clear that the DWPT able to characterize the EEG signal corresponding to each wave at a specific frequency. Furthermore, the numerical results obtained better than the results using DWT. Statistical analysis support our main findings.

  12. Engineering biphoton wave packets with an electromagnetically induced grating

    SciTech Connect

    Wen Jianming; Xiao Min; Zhai Yanhua; Du Shengwang

    2010-10-15

    We propose to shape biphoton wave packets with an electromagnetically induced grating in a four-level double-{Lambda} cold atomic system. We show that the induced hybrid grating plays an essential role in directing the new fields into different angular positions, especially for the zeroth-order diffraction. A number of interesting features appears in the shaped two-photon wave forms. For example, broadening or narrowing the spectrum would be possible in the proposed scheme even without the use of a cavity.

  13. Optimizing bandwidth utilization in packet based telemetry systems

    SciTech Connect

    Kalibjian, J.R.

    1995-10-17

    A consistent theme in spacecraft telemetry system design is the desire to obtain maximum bandwidth utilization given a fixed transmission capability (usually due to cost/weight criteria). Extensions to basic packetization telemetry architectures are discussed which can facilitate a reduction in the amount of actual data telemetered, without loss of data quality. Central to the extensions are the establishment of an ``intelligent`` telemetry process, which can evaluate pending data to be telemetered, and act to compress, discard, or re-formulate data before actual transmission to ground stations.

  14. A Wavelet Packets Approach to Electrocardiograph Baseline Drift Cancellation

    PubMed Central

    Mozaffary, Behzad

    2006-01-01

    Baseline wander elimination is considered a classical problem. In electrocardiography (ECG) signals, baseline drift can influence the accurate diagnosis of heart disease such as ischemia and arrhythmia. We present a wavelet-transform- (WT-) based search algorithm using the energy of the signal in different scales to isolate baseline wander from the ECG signal. The algorithm computes wavelet packet coefficients and then in each scale the energy of the signal is calculated. Comparison is made and the branch of the wavelet binary tree corresponding to higher energy wavelet spaces is chosen. This algorithm is tested using the data record from MIT/BIH database and excellent results are obtained. PMID:23165064

  15. A dynamic packet-switching system for satellite broadcast channels

    NASA Technical Reports Server (NTRS)

    Binder, R.

    1975-01-01

    A new satellite multi-access scheme for packet-switching computer communications combines a dynamic allocation technique with conventional time-division multiplexing to minimize delays and maximize traffic thruput. The scheme is designed to give the shortest delays to short-duration interactive or priority traffic, at the expense of longer delays for large data transfers. Simulation results show markedly improved delay-thruput characteristics over conventional time-division multiplexing for a wide range of traffic mixes, with especially significant performance gains as the traffic imbalance among the nodes increases.

  16. Wave-packet evolution in non-Hermitian quantum systems

    SciTech Connect

    Graefe, Eva-Maria; Schubert, Roman

    2011-06-15

    The quantum evolution of the Wigner function for Gaussian wave packets generated by a non-Hermitian Hamiltonian is investigated. In the semiclassical limit ({h_bar}/2{pi}){yields}0 this yields the non-Hermitian analog of the Ehrenfest theorem for the dynamics of observable expectation values. The lack of Hermiticity reveals the importance of the complex structure on the classical phase space: The resulting equations of motion are coupled to an equation of motion for the phase-space metric - a phenomenon having no analog in Hermitian theories.

  17. Simulation of the collapse and dissipation of Langmuir wave packets

    NASA Technical Reports Server (NTRS)

    Newman, D. L.; Winglee, R. M.; Robinson, P. A.; Glanz, J.; Goldman, M. V.

    1990-01-01

    Particle-in-cell (PIC) simulations and Zakharov's partial differential equations (PDEs) are used to investigate the collapse of isolated Langmuir wave packets in two dimensions. Collapse thresholds are determined numerically, and the roles of enhanced Langmuir wave damping and nonlinearities not included in the standard Zakharov equations are discussed. The Langmuir wave and ion dynamics in PIC simulations are compared with the predictions of PDE simulations incorporating enhanced Langmuir damping. Electron heating and coherent acceleration in the PIC simulations are discussed and compared with predictions of the transit-time theory.

  18. Correlation of femtosecond wave packets and fluorescence interference in a conjugated polymer: Towards the measurement of site homogeneous dephasing

    NASA Astrophysics Data System (ADS)

    Milota, F.; Sperling, J.; Szöcs, V.; Tortschanoff, A.; Kauffmann, H. F.

    2004-05-01

    Probing electronic femtosecond (fs) coherence among segmental sites that are congested by static and dynamic site disorder and subject to structural relaxation is a big, experimental challenge in the study of photophysics of poly(p-phenylenevinylene). In this work, fs-wave-packet fluorescence interferometry experiments are presented that measure macroscopic coherent kernels and their phase-relaxation in the low-temperature, bottom-state regime of the density-of-states below the migrational threshold energy where downhill site-to-site transfer is marginal. By using freely propagating and tunable 70 fs excitation/probing pulses and employing narrow-band spectral filtering of wave packets, fluorescence interferograms with strongly damped beatings can be observed. The coherences formally follow the in-phase superpositions of two site-optical free-induction-decays and originate from distinct pairs of coherent doorway-states, different in energy and space, each of them being targeted, by two discrete quantum-arrival-states 1α and 1β, via independent, isoenergetic 0→1 fluorescence transitions. The coherent transients are explained as site-to-site polarization beatings, caused by the interference of two fluorescence correlation signals. The numerical analysis of the damping regime, based upon second-order perturbational solutions, reveals the lower limit value of homogeneous dephasing in the range from T2≃100 fs to T2≃200 fs depending on the site-excitation energy of the bottom-states. The experiments enable to look into the formation of the relaxed state as a special molecular process of electron-phonon coupling and hence open-up a quite new perspective in the puzzle of multichromophore optical dynamics and structural relaxation in conjugated polymers.

  19. Anchorage Arrival Scheduling Under Off-Nominal Weather Conditions

    NASA Technical Reports Server (NTRS)

    Grabbe, Shon; Chan, William N.; Mukherjee, Avijit

    2012-01-01

    Weather can cause flight diversions, passenger delays, additional fuel consumption and schedule disruptions at any high volume airport. The impacts are particularly acute at the Ted Stevens Anchorage International Airport in Anchorage, Alaska due to its importance as a major international portal. To minimize the impacts due to weather, a multi-stage scheduling process is employed that is iteratively executed, as updated aircraft demand and/or airport capacity data become available. The strategic scheduling algorithm assigns speed adjustments for flights that originate outside of Anchorage Center to achieve the proper demand and capacity balance. Similarly, an internal departure-scheduling algorithm assigns ground holds for pre-departure flights that originate from within Anchorage Center. Tactical flight controls in the form of airborne holding are employed to reactively account for system uncertainties. Real-world scenarios that were derived from the January 16, 2012 Anchorage visibility observations and the January 12, 2012 Anchorage arrival schedule were used to test the initial implementation of the scheduling algorithm in fast-time simulation experiments. Although over 90% of the flights in the scenarios arrived at Anchorage without requiring any delay, pre-departure scheduling was the dominant form of control for Anchorage arrivals. Additionally, tactical scheduling was used extensively in conjunction with the pre-departure scheduling to reactively compensate for uncertainties in the arrival demand. For long-haul flights, the strategic scheduling algorithm performed best when the scheduling horizon was greater than 1,000 nmi. With these long scheduling horizons, it was possible to absorb between ten and 12 minutes of delay through speed control alone. Unfortunately, the use of tactical scheduling, which resulted in airborne holding, was found to increase as the strategic scheduling horizon increased because of the additional uncertainty in the arrival times

  20. Dynamics of fire ant aggregations

    NASA Astrophysics Data System (ADS)

    Tennenbaum, Michael; Hu, David; Fernandez-Nieves, Alberto

    Fire ant aggregations are an inherently active system. Each ant harvests its own energy and can convert it into motion. The motion of individual ants contributes non-trivially to the bulk material properties of the aggregation. We have measured some of these properties using plate-plate rheology, where the response to an applied external force or deformation is measured. In this talk, we will present data pertaining to the aggregation behavior in the absence of any external force. We quantify the aggregation dynamics by monitoring the rotation of the top plate and by measuring the normal force. We then compare the results with visualizations of 2D aggregations.

  1. STS-86 Mission Specialist Wolf arrives at SLF before launch

    NASA Technical Reports Server (NTRS)

    1997-01-01

    STS-86 Mission Specialist David A. Wolf, the next U.S. astronaut slated to live and work on the Russian Space Station Mir, is all smiles after his arrival at KSCs Shuttle Landing Facility on Monday. Wolf is making his second spaceflight on STS-86, scheduled to be the seventh docking of the Shuttle with the Mir. After the docking, Wolf will transfer to the Mir for an approximate four-month stay. He replaces U.S. astronaut C. Michael Foale, who arrived at Mir in May and will return to Earth with the remainder of the STS-86 crew.

  2. A new pulse arrival-time recording system

    SciTech Connect

    Arnone, G.J.

    1996-12-31

    We describe a new pulse arrival-time recording system that is being developed at Los Alamos. The new PATRM/PCI (Pulse Arrival-Time Recording Module/Peripheral Component Interconnect) has had several features added. These features enhance our time-correlation measurement capabilities. By applying the latest advances in electronics and computer technology we are able to increase capability over existing instrumentation while lowering the per channel cost. The modular design approach taken allows easy configuration of both small and large systems.

  3. Kinetics of protein aggregation

    NASA Astrophysics Data System (ADS)

    Knowles, Tuomas

    2015-03-01

    Aggregation into linear nanostructures, notably amyloid and amyloid-like fibrils, is a common form of behaviour exhibited by a range of peptides and proteins. This process was initially discovered in the context of the aetiology of a range of neurodegenerative diseases, but has recently been recognised to of general significance and has been found at the origin of a number of beneficial functional roles in nature, including as catalytic scaffolds and functional components in biofilms. This talk discusses our ongoing efforts to study the kinetics of linear protein self-assembly by using master equation approaches combined with global analysis of experimental data.

  4. Structure of Viral Aggregates

    NASA Astrophysics Data System (ADS)

    Barr, Stephen; Luijten, Erik

    2010-03-01

    The aggregation of virus particles is a particular form of colloidal self-assembly, since viruses of a give type are monodisperse and have identical, anisotropic surface charge distributions. In small-angle X-ray scattering experiments, the Qbeta virus was found to organize in different crystal structures in the presence of divalent salt and non-adsorbing polymer. Since a simple isotropic potential cannot explain the occurrence of all observed phases, we employ computer simulations to investigate how the surface charge distribution affects the virus interactions. Using a detailed model of the virus particle, we find an asymmetric ion distribution around the virus which gives rise to the different phases observed.

  5. Non-Hermitian wave packet approximation of Bloch optical equations

    SciTech Connect

    Charron, Eric; Sukharev, Maxim

    2013-01-14

    We introduce a non-Hermitian approximation of Bloch optical equations. This approximation provides a complete description of the excitation, relaxation, and decoherence dynamics of ensembles of coupled quantum systems in weak laser fields, taking into account collective effects and dephasing. In the proposed method, one propagates the wave function of the system instead of a complete density matrix. Relaxation and dephasing are taken into account via automatically adjusted time-dependent gain and decay rates. As an application, we compute the numerical wave packet solution of a time-dependent non-Hermitian Schroedinger equation describing the interaction of electromagnetic radiation with a quantum nano-structure, and compare the calculated transmission, reflection, and absorption spectra with those obtained from the numerical solution of the Liouville-von Neumann equation. It is shown that the proposed wave packet scheme is significantly faster than the propagation of the full density matrix while maintaining small error. We provide the key ingredients for easy-to-use implementation of the proposed scheme and identify the limits and error scaling of this approximation.

  6. Application of wavelet packet transform to compressing Raman spectra data

    NASA Astrophysics Data System (ADS)

    Chen, Chen; Peng, Fei; Cheng, Qinghua; Xu, Dahai

    2008-12-01

    Abstract The Wavelet transform has been established with the Fourier transform as a data-processing method in analytical fields. The main fields of application are related to de-noising, compression, variable reduction, and signal suppression. Raman spectroscopy (RS) is characterized by the frequency excursion that can show the information of molecule. Every substance has its own feature Raman spectroscopy, which can analyze the structure, components, concentrations and some other properties of samples easily. RS is a powerful analytical tool for detection and identification. There are many databases of RS. But the data of Raman spectrum needs large space to storing and long time to searching. In this paper, Wavelet packet is chosen to compress Raman spectra data of some benzene series. The obtained results show that the energy retained is as high as 99.9% after compression, while the percentage for number of zeros is 87.50%. It was concluded that the Wavelet packet has significance in compressing the RS data.

  7. Packet Drop Avoidance for High-speed network transmission protocol

    SciTech Connect

    Jin, Guojun

    2004-05-01

    As network bandwidth continues to grow and longer paths are used to exchange large scientific data between storage systems and GRID computation, it has become increasingly obvious that there is a need to deploy a packet drop avoidance mechanism into network transmission protocols. Current end-to-end congestion avoidance mechanisms used in Transmission Control Protocol (TCP) have worked well on low bandwidth delay product networks, but with newer high-bandwidth delay networks they have shown to be inefficient and prone to unstable. This is largely due to increased network bandwidth coupled with changes in internet traffic patterns. These changes come from a variety of new network applications that are being developed to take advantage of the increased network bandwidth. This paper will examine the end-to-end congestion avoidance mechanism and perform a step-by-step analysis of its theory. In addition we will propose an alternative approach developed as part of a new network transmission protocol. Our alternative protocol uses a packet drop avoidance (PDA) mechanism built on top of the maximum burst size (MBS) theory combined with a real-time available bandwidth algorithm.

  8. Wave packet spreading and localization in electron-nuclear scattering

    NASA Astrophysics Data System (ADS)

    Markmann, Andreas; Grabowski*, P. E.; Morozov, I. V.; Valuev, I. A.; Fichtl, C. A.; Batista, V. S.; Graziani, F. R.; Murillo, M. S.; Cimarron Collaboration

    2013-10-01

    The wave packet molecular dynamics (WPMD) method solves the time-dependent Schrödinger equation via a variational approximation. Application to high-temperature dense plasmas has yielded diverging electron width (spreading) with diminished electron-nuclear interaction. This was previously ascribed to a shortcoming of WPMD and has been counteracted by heuristic additions to the model. We employ various methods to determine if spreading continues to be predicted. Single electron scattering on a periodic array of statically screened protons is used as a model problem for comparison via the numerically exact split operator Fourier transform method, the Wigner trajectory method, and the time-dependent variational principle (TDVP). Within the TDVP, we use as ansätze the standard form of WPMD, a single Gaussian wave packet (WP), as well as the split WP method, a linear combination of Gaussian WPs. Spreading is predicted by all methods, so is not the cause of unphysical diminishing interactions in WPMD. Instead, the Gaussian WP's inability to reproduce breakup of the density into fragments localized near ions is responsible for the deviation between methods. Hence, extensions of WPMD must include a mechanism for breakup. Authors contributed equally.

  9. 8 CFR 251.1 - Arrival manifests and lists.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ...) General. The master or agent of every vessel arriving in the United States from a foreign place or an... List, in accordance with the instructions contained thereon. (2) Longshore work notations. The master... performed, the master or agent shall note which exception listed in section 258 of the Act permits the...

  10. 7 CFR 319.37-11 - Arrival notification.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Arrival notification. 319.37-11 Section 319.37-11 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Nursery Stock, Plants, Roots, Bulbs,...

  11. 7 CFR 319.37-11 - Arrival notification.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Arrival notification. 319.37-11 Section 319.37-11 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Nursery Stock, Plants, Roots, Bulbs,...

  12. Self-Regulation in Newly Arrived International Adoptees

    ERIC Educational Resources Information Center

    Tirella, Linda Grey; Miller, Laurie C.

    2011-01-01

    Many newly arrived international adoptees (IA) have difficulties with eating, sleeping, and self-soothing/self-stimulating (SS) behaviors. However, to date the prevalence of these problems and associated risk factors have not been clearly identified. Therefore, we proposed to evaluate 387 IA for the presence of these self-regulation and behavioral…

  13. "Reading between the Pictures": Immigrant Students' Interpretations of "The Arrival"

    ERIC Educational Resources Information Center

    Martinez-Roldan, Carmen M.; Newcomer, Sarah

    2011-01-01

    In this article, the authors share findings from a study in which immigrant students responded to the wordless text "The Arrival" in small-group, bilingual literature discussions. The interpretive processes of two of the children with different ethnic backgrounds, levels of English proficiency, and styles of response are highlighted as exemplary…

  14. Gemini 12 crew arrives aboard U.S.S. Wasp

    NASA Technical Reports Server (NTRS)

    1966-01-01

    A happy Gemini 12 prime crew arrives aboard the aircraft carrier, U.S.S. Wasp. Astronauts James A. Lovell Jr. (left), command pilot, and Edwin E. Aldrin Jr., pilot, had just been picked up from the splashdown area by helicopter.

  15. 14 CFR 93.29 - International Arrival Authorizations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... marketing arrangement unless the flight was predominately marketed, by contract, under the control of another Carrier. If the flight was under the marketing control of another Carrier or the entire inventory... foreign carrier arriving from a foreign point or the continuation of a flight that begins at a...

  16. Miracle or Menace?: The Arrival of Cocaine 1860-1900.

    PubMed

    Jay, Mike

    2015-01-01

    The arrival of cocaine was the formative episode in the modern understanding of the benefits and dangers of neurostimulants. European culture and medicine had historically been poor in stimulant plants and drugs. When coca and cocaine appeared in nineteenth-century Europe, doctors, pharmacists, and the public struggled to understand their benefits and risks, and to formulate a distinction between use and abuse.

  17. 7 CFR 319.75-6 - Arrival notification.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 5 2013-01-01 2013-01-01 false Arrival notification. 319.75-6 Section 319.75-6 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Khapra Beetle § 319.75-6...

  18. 7 CFR 319.75-6 - Arrival notification.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 5 2012-01-01 2012-01-01 false Arrival notification. 319.75-6 Section 319.75-6 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Khapra Beetle § 319.75-6...

  19. 7 CFR 319.75-6 - Arrival notification.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 5 2011-01-01 2011-01-01 false Arrival notification. 319.75-6 Section 319.75-6 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Khapra Beetle § 319.75-6...

  20. 7 CFR 319.75-6 - Arrival notification.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Arrival notification. 319.75-6 Section 319.75-6 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Khapra Beetle § 319.75-6...

  1. 7 CFR 319.75-6 - Arrival notification.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 5 2014-01-01 2014-01-01 false Arrival notification. 319.75-6 Section 319.75-6 Agriculture Regulations of the Department of Agriculture (Continued) ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Khapra Beetle § 319.75-6...

  2. Apollo 9 crewmen arrive aboard U.S.S. Guadelcanal

    NASA Technical Reports Server (NTRS)

    1969-01-01

    The Apollo 9 crewmen arrive aboard the U.S.S. Guadelcanal as they step from a helicopter to receive a red-carpet welcome. Two of the crewmen salute the crowd of newsmen, Navy and NASA personnel gathered to greet them. Left to right are Astronauts Russell L. Schweickart, David R. Scott, and James A. McDivitt.

  3. Simulation Results for Airborne Precision Spacing along Continuous Descent Arrivals

    NASA Technical Reports Server (NTRS)

    Barmore, Bryan E.; Abbott, Terence S.; Capron, William R.; Baxley, Brian T.

    2008-01-01

    This paper describes the results of a fast-time simulation experiment and a high-fidelity simulator validation with merging streams of aircraft flying Continuous Descent Arrivals through generic airspace to a runway at Dallas-Ft Worth. Aircraft made small speed adjustments based on an airborne-based spacing algorithm, so as to arrive at the threshold exactly at the assigned time interval behind their Traffic-To-Follow. The 40 aircraft were initialized at different altitudes and speeds on one of four different routes, and then merged at different points and altitudes while flying Continuous Descent Arrivals. This merging and spacing using flight deck equipment and procedures to augment or implement Air Traffic Management directives is called Flight Deck-based Merging and Spacing, an important subset of a larger Airborne Precision Spacing functionality. This research indicates that Flight Deck-based Merging and Spacing initiated while at cruise altitude and well prior to the Terminal Radar Approach Control entry can significantly contribute to the delivery of aircraft at a specified interval to the runway threshold with a high degree of accuracy and at a reduced pilot workload. Furthermore, previously documented work has shown that using a Continuous Descent Arrival instead of a traditional step-down descent can save fuel, reduce noise, and reduce emissions. Research into Flight Deck-based Merging and Spacing is a cooperative effort between government and industry partners.

  4. 19 CFR 122.118 - Exportation from port of arrival.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... port of arrival within 10 days from the date the exporting airline receives the cargo. After the 10-day... Customs. (1) Review copy. The importing airline shall file a copy of each transit air cargo manifest sheet... soon as the exporting airline has been chosen. The exporting airline need not give receipt on...

  5. 19 CFR 122.118 - Exportation from port of arrival.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... port of arrival within 10 days from the date the exporting airline receives the cargo. After the 10-day... Customs. (1) Review copy. The importing airline shall file a copy of each transit air cargo manifest sheet... soon as the exporting airline has been chosen. The exporting airline need not give receipt on...

  6. 19 CFR 122.118 - Exportation from port of arrival.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... port of arrival within 10 days from the date the exporting airline receives the cargo. After the 10-day... Customs. (1) Review copy. The importing airline shall file a copy of each transit air cargo manifest sheet... soon as the exporting airline has been chosen. The exporting airline need not give receipt on...

  7. 19 CFR 122.118 - Exportation from port of arrival.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... port of arrival within 10 days from the date the exporting airline receives the cargo. After the 10-day... Customs. (1) Review copy. The importing airline shall file a copy of each transit air cargo manifest sheet... soon as the exporting airline has been chosen. The exporting airline need not give receipt on...

  8. 19 CFR 122.118 - Exportation from port of arrival.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... port of arrival within 10 days from the date the exporting airline receives the cargo. After the 10-day... Customs. (1) Review copy. The importing airline shall file a copy of each transit air cargo manifest sheet... soon as the exporting airline has been chosen. The exporting airline need not give receipt on...

  9. A Comparison of CTAS and Airline Time of Arrival Predictions

    NASA Technical Reports Server (NTRS)

    Heere, Karen R.; Zelenka, Richard E.; Hsu, Rose Y.

    1999-01-01

    A statistically-based comparison of aircraft times of arrival between Center/TRACON Automation System (CTAS) air traffic control scheduling and airline predictions is presented. CTAS is found to provide much improved values, forming the foundation for airline operational improvements, as observed during an airline field trial of a CTAS display.

  10. ELECTRICAL LINES ARRIVE FROM CENTRAL FACILITIES AREA, SOUTH OF MTR. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    ELECTRICAL LINES ARRIVE FROM CENTRAL FACILITIES AREA, SOUTH OF MTR. EXCAVATION RUBBLE IN FOREGROUND. CONTRACTOR CRAFT SHOPS, CRANES, AND OTHER MATERIALS ON SITE. CAMERA FACES EAST, WITH LITTLE BUTTE AND MIDDLE BUTTE IN DISTANCE. INL NEGATIVE NO. 335. Unknown Photographer, 7/1/1950 - Idaho National Engineering Laboratory, Test Reactor Area, Materials & Engineering Test Reactors, Scoville, Butte County, ID

  11. Estimating Radar Velocity using Direction of Arrival Measurements

    SciTech Connect

    Doerry, Armin Walter; Horndt, Volker; Bickel, Douglas Lloyd; Naething, Richard M.

    2014-09-01

    Direction of Arrival (DOA) measurements, as with a monopulse antenna, can be compared against Doppler measurements in a Synthetic Aperture Radar ( SAR ) image to determine an aircraft's forward velocity as well as its crab angle, to assist the aircraft's navigation as well as improving high - performance SAR image formation and spatial calibration.

  12. STS-87 Crew arrives at KSC for TCDT

    NASA Technical Reports Server (NTRS)

    1997-01-01

    In preparation for Space Shuttle Mission STS-87, the crew arrives at the Kennedy Space Center Shuttle Landing Facility to participate in the Terminal Countdown Demonstration Test (TCDT) for their mission. The TCDT is a dress rehearsal for launch. STS- 87 will be the fourth flight of the United States Microgravity Payload and the Spartan-201 deployable satellite. Launch is targeted for Nov. 19.

  13. Taurine and platelet aggregation

    SciTech Connect

    Nauss-Karol, C.; VanderWende, C.; Gaut, Z.N.

    1986-03-01

    Taurine is a putative neurotransmitter or neuromodulator. The endogenous taurine concentration in human platelets, determined by amino acid analysis, is 15 ..mu..M/g. In spite of this high level, taurine is actively accumulated. Uptake is saturable, Na/sup +/ and temperature dependent, and suppressed by metabolic inhibitors, structural analogues, and several classes of centrally active substances. High, medium and low affinity transport processes have been characterized, and the platelet may represent a model system for taurine transport in the CNS. When platelets were incubated with /sup 14/C-taurine for 30 minutes, then resuspended in fresh medium and reincubated for one hour, essentially all of the taurine was retained within the cells. Taurine, at concentrations ranging from 10-1000 ..mu..M, had no effect on platelet aggregation induced by ADP or epinephrine. However, taurine may have a role in platelet aggregation since 35-39% of the taurine taken up by human platelets appears to be secreted during the release reaction induced by low concentrations of either epinephrine or ADP, respectively. This release phenomenon would imply that part of the taurine taken up is stored directly in the dense bodies of the platelet.

  14. Research Of Airborne Precision Spacing to Improve Airport Arrival Operations

    NASA Technical Reports Server (NTRS)

    Barmore, Bryan E.; Baxley, Brian T.; Murdoch, Jennifer L.

    2011-01-01

    In September 2004, the European Organization for the Safety of Air Navigation (EUROCONTROL) and the United States Federal Aviation Administration (FAA) signed a Memorandum of Cooperation to mutually develop, modify, test, and evaluate systems, procedures, facilities, and devices to meet the need for safe and efficient air navigation and air traffic control in the future. In the United States and Europe, these efforts are defined within the architectures of the Next Generation Air Transportation System (NextGen) Program and Single European Sky Air Traffic Management Research (SESAR) Program respectively. Both programs have identified Airborne Spacing as a critical component, with Automatic Dependent Surveillance Broadcast (ADS-B) as a key enabler. Increased interest in reducing airport community noise and the escalating cost of aviation fuel has led to the use of Continuous Descent Arrival (CDA) procedures to reduce noise, emissions, and fuel usage compared to current procedures. To provide these operational enhancements, arrival flight paths into terminal areas are planned around continuous vertical descents that are closer to an optimum trajectory than those in use today. The profiles are designed to be near-idle descents from cruise altitude to the Final Approach Fix (FAF) and are typically without any level segments. By staying higher and faster than conventional arrivals, CDAs also save flight time for the aircraft operator. The drawback is that the variation of optimized trajectories for different types and weights of aircraft requires the Air Traffic Controller to provide more airspace around an aircraft on a CDA than on a conventional arrival procedure. This additional space decreases the throughput rate of the destination airport. Airborne self-spacing concepts have been developed to increase the throughput at high-demand airports by managing the inter-arrival spacing to be more precise and consistent using on-board guidance. It has been proposed that the

  15. Separation Assurance and Scheduling Coordination in the Arrival Environment

    NASA Technical Reports Server (NTRS)

    Aweiss, Arwa S.; Cone, Andrew C.; Holladay, Joshua J.; Munoz, Epifanio; Lewis, Timothy A.

    2016-01-01

    Separation assurance (SA) automation has been proposed as either a ground-based or airborne paradigm. The arrival environment is complex because aircraft are being sequenced and spaced to the arrival fix. This paper examines the effect of the allocation of the SA and scheduling functions on the performance of the system. Two coordination configurations between an SA and an arrival management system are tested using both ground and airborne implementations. All configurations have a conflict detection and resolution (CD&R) system and either an integrated or separated scheduler. Performance metrics are presented for the ground and airborne systems based on arrival traffic headed to Dallas/ Fort Worth International airport. The total delay, time-spacing conformance, and schedule conformance are used to measure efficiency. The goal of the analysis is to use the metrics to identify performance differences between the configurations that are based on different function allocations. A surveillance range limitation of 100 nmi and a time delay for sharing updated trajectory intent of 30 seconds were implemented for the airborne system. Overall, these results indicate that the surveillance range and the sharing of trajectories and aircraft schedules are important factors in determining the efficiency of an airborne arrival management system. These parameters are not relevant to the ground-based system as modeled for this study because it has instantaneous access to all aircraft trajectories and intent. Creating a schedule external to the CD&R and the scheduling conformance system was seen to reduce total delays for the airborne system, and had a minor effect on the ground-based system. The effect of an external scheduler on other metrics was mixed.

  16. Does Pet Arrival Trigger Prosocial Behaviors in Individuals with Autism?

    PubMed Central

    Grandgeorge, Marine; Tordjman, Sylvie; Lazartigues, Alain; Lemonnier, Eric; Deleau, Michel; Hausberger, Martine

    2012-01-01

    Alteration of social interactions especially prosocial behaviors – an important aspect of development – is one of the characteristics of autistic disorders. Numerous strategies or therapies are used to improve communication skills or at least to reduce social impairments. Animal-assisted therapies are used widely but their relevant benefits have never been scientifically evaluated. In the present study, we evaluated the association between the presence or the arrival of pets in families with an individual with autism and the changes in his or her prosocial behaviors. Of 260 individuals with autism - on the basis of presence or absence of pets - two groups of 12 individuals and two groups of 8 individuals were assigned to: study 1 (pet arrival after age of 5 versus no pet) and study 2 (pet versus no pet), respectively. Evaluation of social impairment was assessed at two time periods using the 36-items ADI-R algorithm and a parental questionnaire about their child-pet relationships. The results showed that 2 of the 36 items changed positively between the age of 4 to 5 (t0) and time of assessment (t1) in the pet arrival group (study 1): “offering to share” and “offering comfort”. Interestingly, these two items reflect prosocial behaviors. There seemed to be no significant changes in any item for the three other groups. The interactions between individuals with autism and their pets were more – qualitatively and quantitatively - reported in the situation of pet arrival than pet presence since birth. These findings open further lines of research on the impact of pet’s presence or arrival in families with an individual with autism. Given the potential ability of individuals with autism to develop prosocial behaviors, related studies are needed to better understand the mechanisms involved in the development of such child-pet relationship. PMID:22870246

  17. 8 CFR 251.5 - Paper arrival and departure manifests for crew.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 8 Aliens and Nationality 1 2012-01-01 2012-01-01 false Paper arrival and departure manifests for... REGULATIONS ARRIVAL AND DEPARTURE MANIFESTS AND LISTS: SUPPORTING DOCUMENTS § 251.5 Paper arrival and... from the United States must submit arrival and departure manifests in a paper format in accordance...

  18. Creation of multihole molecular wave packets via strong-field ionization

    SciTech Connect

    Geissler, Dominik; Weinacht, Thomas; Rozgonyi, Tamas; Gonzalez-Vazquez, Jesus; Gonzalez, Leticia; Nichols, Sarah

    2010-07-15

    We demonstrate the creation of vibrational wave packets on multiple electronic states of a molecule via strong-field ionization. Furthermore, we show that the relative contribution of the different electronic states depends on the shape of the laser pulse which launches the wave packets.

  19. Fokker-Planck approach to the pulse packet propagation in synfire chain.

    PubMed

    Câteau, H; Fukai, T

    2001-01-01

    We applied the Fokker-Planck method to the so-called 'synfire chain' network model and showed how a synchronous population spike (pulse packet) evolves to a narrow pulse packet (width < 1 ms) or fades away, depending on its initial size and width. The results of numerical integration of the Fokker-Planck equation are in good agreement with those of simulations on a network of leaky integrate-and-fire neurons. For a narrow input pulse packet, the integration of the Fokker-Planck equation requires careful numerical treatment. However, we can construct a precise analytical waveform of an output packet, which proves valid for narrow input pulse packets, from the stationary solution to the Fokker-Planck equation and a previously proposed approximate input-output relationship. Our methods enable us also to understand an essential role of the synaptic noise in the evolution, the peculiar temporal evolution of a broader pulse packets, and the irrelevance of the refractory period in determining the waveform of a pulse packet. Furthermore, we elucidate possible functional roles of multiple interactive pulse packets in spatiotemporal information processing, i.e. the association of information and the temporal competition. PMID:11665762

  20. A multi-function IEC 61850 packet generator based on FPGA

    NASA Astrophysics Data System (ADS)

    Wei, Wei; Li, Hong-bin; Cheng, Han-miao

    2016-07-01

    An IEC 61850 packet generator is used to produce IEC 61850-9-2 packets by simulating the merging unit and testing the IEC 61850 digital device. While the existing IEC packet generator can produce ideal digital without any noise, it does not take into account the fact that the merging unit output signal packets will be inevitably superimposed with noise. Since the International Electrical Commission standard of the electronic current transformer specifies the minimum output signal-to-noise ratio of the merging unit to be 30 dB, and the signal superimposed with noise will influence the operation performance of the digital device, it is necessary to design a multi-function IEC 61850-9-2 packet generator for a digital device test. Therefore, in this paper, a multi-function IEC 61850 packet generator has been developed, which not only can output various IEC 61850-9-2 packets, but also can add white Gaussian noise to the signal for digital device testing. By testing three digital electricity meters from different manufacturers, we showed that the error of the digital electricity meter is significantly larger when the signal packet is superimposed with noise. Also when the signal-to-noise ration is 30 dB, the error of one of the meters exceeds the allowed range of the accuracy class. This indicates that the noise testing and the noise setting function of the system has an important role in the testing of a digital device.

  1. PROJECT SUCCESS: Marine Science. (Introductory Packet, Basic Marine Science Laboratory Techniques, Oceanographic Instruments, Individual Projects, Bibliography).

    ERIC Educational Resources Information Center

    Demaray, Bryan

    Five packets comprise the marine science component of an enrichment program for gifted elementary students. Considered in the introductory section are identification (pre/post measure) procedures. Remaining packets address the following topics (subtopics in parentheses): basic marine science laboratory techniques (microscope techniques and metric…

  2. Animal Homes and Habitats. A Fall Activity Packet for Third Grade.

    ERIC Educational Resources Information Center

    Jackson Community Coll., MI. Dahlem Environmental Education Center.

    This instructional packet is one of 14 school environmental education programs developed for use in the classroom and at the Dahlem Environmental Education Center (DEEC) of the Jackson Community College (Michigan). Provided in the packet are pre-trip activities, field trip activities, and post-trip activities which focus on animal populations and…

  3. Mae Conn and Associates. A Legal Secretary Position Simulation. Student Packet 3. Office Occupations.

    ERIC Educational Resources Information Center

    Georgia State Univ., Atlanta.

    This is the third of four student packets forming part of a position simulation for use in an office applications laboratory at the postsecondary level. The purpose of the simulation is to give the student an opportunity to learn the tasks and duties performed by a legal secretary. The packet, which begins with a simulated office schedule for one…

  4. Observation of wave packet distortion during a negative-group-velocity transmission.

    PubMed

    Ye, Dexin; Salamin, Yannick; Huangfu, Jiangtao; Qiao, Shan; Zheng, Guoan; Ran, Lixin

    2015-01-29

    In Physics, causality is a fundamental postulation arising from the second law of thermodynamics. It states that, the cause of an event precedes its effect. In the context of Electromagnetics, the relativistic causality limits the upper bound of the velocity of information, which is carried by electromagnetic wave packets, to the speed of light in free space (c). In anomalously dispersive media (ADM), it has been shown that, wave packets appear to propagate with a superluminal or even negative group velocity. However, Sommerfeld and Brillouin pointed out that the "front" of such wave packets, known as the initial point of the Sommerfeld precursor, always travels at c. In this work, we investigate the negative-group-velocity transmission of half-sine wave packets. We experimentally observe the wave front and the distortion of modulated wave packets propagating with a negative group velocity in a passive artificial ADM in microwave regime. Different from previous literature on the propagation of superluminal Gaussian packets, strongly distorted sinusoidal packets with non-superluminal wave fronts were observed. This result agrees with Brillouin's assertion, i.e., the severe distortion of seemingly superluminal wave packets makes the definition of group velocity physically meaningless in the anomalously dispersive region.

  5. Multiwavelet packet entropy and its application in transmission line fault recognition and classification.

    PubMed

    Liu, Zhigang; Han, Zhiwei; Zhang, Yang; Zhang, Qiaoge

    2014-11-01

    Multiwavelets possess better properties than traditional wavelets. Multiwavelet packet transformation has more high-frequency information. Spectral entropy can be applied as an analysis index to the complexity or uncertainty of a signal. This paper tries to define four multiwavelet packet entropies to extract the features of different transmission line faults, and uses a radial basis function (RBF) neural network to recognize and classify 10 fault types of power transmission lines. First, the preprocessing and postprocessing problems of multiwavelets are presented. Shannon entropy and Tsallis entropy are introduced, and their difference is discussed. Second, multiwavelet packet energy entropy, time entropy, Shannon singular entropy, and Tsallis singular entropy are defined as the feature extraction methods of transmission line fault signals. Third, the plan of transmission line fault recognition using multiwavelet packet entropies and an RBF neural network is proposed. Finally, the experimental results show that the plan with the four multiwavelet packet energy entropies defined in this paper achieves better performance in fault recognition. The performance with SA4 (symmetric antisymmetric) multiwavelet packet Tsallis singular entropy is the best among the combinations of different multiwavelet packets and the four multiwavelet packet entropies.

  6. In the Public Interest: Law, Government, and Media. Maryland Women's History Resource Packet--1986.

    ERIC Educational Resources Information Center

    Maryland State Commission for Women, Baltimore.

    Designed to be used for National Women's History Week (March 2-8), this 1986 Maryland women's history resource packet centers around Maryland women who have made significant volunteer and career contributions in the areas of government, law, and the public interest media. The packet begins with suggested student activity lists and activity sheets…

  7. Japanese Painting: Form and Function. A Teacher Workshop on May 14, 1994. Teacher's Packet.

    ERIC Educational Resources Information Center

    Schardt, Molly; And Others

    This packet accompanies a slide series designed to introduce students to Japanese painting from the 12th century to the late 19th century. The packet includes an essay introduction to establish a historical framework, maps of the region, a time line of the chronology of Japan from 2000 B.C. to the present, illustrations of various art forms, a…

  8. Women's Studies for Teachers and Administrators: A Packet of Inservice Education Materials.

    ERIC Educational Resources Information Center

    Froschl, Merle, Ed.; And Others

    This packet of materials is designed for elementary and secondary teachers and administrators who are engaged in inservice education and interested in the movement to eliminate sexism in schools. Two major purposes of the packet are to help a school district start an inservice course on sexism in education and to show the potential of such a…

  9. Generation of attosecond electron packets via conical surface plasmon electron acceleration

    NASA Astrophysics Data System (ADS)

    Greig, S. R.; Elezzabi, A. Y.

    2016-01-01

    We present a method for the generation of high kinetic energy attosecond electron packets via magnetostatic and aperture filtering of conical surface plasmon (SP) accelerated electrons. The conical SP waves are excited by coupling an ultrafast radially polarized laser beam to a conical silica lens coated with an Ag film. Electromagnetic and particle tracking models are employed to characterize the ultrafast electron packets.

  10. Observation of Wave Packet Distortion during a Negative-Group-Velocity Transmission

    NASA Astrophysics Data System (ADS)

    Ye, Dexin; Salamin, Yannick; Huangfu, Jiangtao; Qiao, Shan; Zheng, Guoan; Ran, Lixin

    2015-01-01

    In Physics, causality is a fundamental postulation arising from the second law of thermodynamics. It states that, the cause of an event precedes its effect. In the context of Electromagnetics, the relativistic causality limits the upper bound of the velocity of information, which is carried by electromagnetic wave packets, to the speed of light in free space (c). In anomalously dispersive media (ADM), it has been shown that, wave packets appear to propagate with a superluminal or even negative group velocity. However, Sommerfeld and Brillouin pointed out that the ``front'' of such wave packets, known as the initial point of the Sommerfeld precursor, always travels at c. In this work, we investigate the negative-group-velocity transmission of half-sine wave packets. We experimentally observe the wave front and the distortion of modulated wave packets propagating with a negative group velocity in a passive artificial ADM in microwave regime. Different from previous literature on the propagation of superluminal Gaussian packets, strongly distorted sinusoidal packets with non-superluminal wave fronts were observed. This result agrees with Brillouin's assertion, i.e., the severe distortion of seemingly superluminal wave packets makes the definition of group velocity physically meaningless in the anomalously dispersive region.

  11. Spacelab Program: Conversion of Spacelab to packet data format. Flight system study

    NASA Technical Reports Server (NTRS)

    1981-01-01

    A study of packetization of the Spacelab data handling system, including the alternate approaches considered and the supporting rationale, is described. It is concluded that it is well within today's state of the art in microelectronics to implement either a full or hybrid packet data system on board the Spacelab. Of the two, the hybrid system is preferred because of the significant cost saving.

  12. The Interesting World of Insects. A Fall Activity Packet for First Grade.

    ERIC Educational Resources Information Center

    Jackson Community Coll., MI. Dahlem Environmental Education Center.

    This instructional packet is one of 14 school environmental education programs developed for use in the classroom and at the Dahlem Environmental Education Center (DEEC) of the Jackson Community College (Michigan). Provided in the packet are pre-trip activities, field trip activities, and post-trip activities which focus on the characteristics and…

  13. The Elegant Art of Thailand. A Teacher Workshop on January 22, 1994. Teacher's Packet.

    ERIC Educational Resources Information Center

    Schardt, Molly; And Others

    This packet accompanies a slide series that introduces students to the art of Thailand. The packet includes maps, a chronology of Southeast Asian history, an essay introduction to the influences on Thai art, a 15-item bibliography for further research, illustrations of Thai ceramics, the slide list, slide descriptions, and slide script. (EH)

  14. Guide to Alternative Mortgage Instruments. Teachers Instructional Packet, TIP No. 4, Spring 1985.

    ERIC Educational Resources Information Center

    Texas A and M Univ., College Station. Texas Real Estate Research Center.

    Part of a series of classroom aids designed for real estate instructors, this instructional packet was developed to help real estate students understand the various alternative mortgage instruments, including their major advantages and disadvantages. First, an evaluation form for the packet is presented. Next, a summary presentation on four basic…

  15. Holographic characterization of protein aggregates

    NASA Astrophysics Data System (ADS)

    Wang, Chen; Zhong, Xiao; Ruffner, David; Stutt, Alexandra; Philips, Laura; Ward, Michael; Grier, David

    Holographic characterization directly measures the size distribution of subvisible protein aggregates in suspension and offers insights into their morphology. Based on holographic video microscopy, this analytical technique records and interprets holograms of individual aggregates in protein solutions as they flow down a microfluidic channel, without requiring labeling or other exceptional sample preparation. The hologram of an individual protein aggregate is analyzed in real time with the Lorenz-Mie theory of light scattering to measure that aggregate's size and optical properties. Detecting, counting and characterizing subvisible aggregates proceeds fast enough for time-resolved studies, and lends itself to tracking trends in protein aggregation arising from changing environmental factors. No other analytical technique provides such a wealth of particle-resolved characterization data in situ. Holographic characterization promises accelerated development of therapeutic protein formulations, improved process control during manufacturing, and streamlined quality assurance during storage and at the point of use. Mrsec and MRI program of the NSF, Spheryx Inc.

  16. Test particle simulation study of whistler wave packets observed near Comet Giacobini-Zinner

    NASA Technical Reports Server (NTRS)

    Kaya, N.; Matsumoto, H.; Tsurutani, B. T.

    1989-01-01

    Nonlinear interactions of water group ions with large-amplitude whistler wave packets detected at the leading edge of steepened magnetosonic waves observed near Comet Giacobini-Zinner (GZ) are studied using test particle simulations of water-ion interactions with a model wave based on GZ data. Some of the water ions are found to be decelerated in the steepened portion of the magnetosonic wave to the resonance velocity with the whistler wave packets. Through resonance and related nonlinear interaction with the large-amplitude whistler waves, the water ions become trapped by the packet. An energy balance calculation demonstrates that the trapped ions lose their kinetic energy during the trapped motion in the packet. Thus, the nonlinear trapping motion in the wave structure leads to effective energy transfer from the water group ions to the whistler wave packets in the leading edge of the steepened MHD waves.

  17. New scheme of variable optical buffer for IP packets used in access control of HORNET

    NASA Astrophysics Data System (ADS)

    Fang, Nian; Wang, Lutang; Huang, Zhaoming

    2002-09-01

    A new scheme of variable optical buffer for IP packets is reported. It may be used in access control of HORNET (Hybrid Optoelectronic Ring NETwork), to avoid collision of added packet and the packet already on the ring and improve the loss ratio of the packets. In this scheme, a new multi-wavelength fiber loop memory technique is employed. This architecture uses the wavelength converter (WC) to specify the packets delay and wavelength conversion is accomplished by the technique of four-wave-mixing (FWM) with a semiconductor optical amplifier (SOA). The range of delay is 10 to 9990 bytes periods. First, architecture, operation principle, characteristics and applications of this scheme of variable optical buffer are introduced. Next, a new unslotted CSMA/CA MAC scheme based on the variable optical buffer is briefly introduced too. Finally, the simulation results are presented.

  18. Quantum dynamics of charge transfer on the one-dimensional lattice: Wave packet spreading and recurrence

    NASA Astrophysics Data System (ADS)

    V, N. Likhachev; O, I. Shevaleevskii; G, A. Vinogradov

    2016-01-01

    The wave function temporal evolution on the one-dimensional (1D) lattice is considered in the tight-binding approximation. The lattice consists of N equal sites and one impurity site (donor). The donor differs from other lattice sites by the on-site electron energy E and the intersite coupling C. The moving wave packet is formed from the wave function initially localized on the donor. The exact solution for the wave packet velocity and the shape is derived at different values E and C. The velocity has the maximal possible group velocity v = 2. The wave packet width grows with time ˜ t1/3 and its amplitude decreases ˜ t-1/3. The wave packet reflects multiply from the lattice ends. Analytical expressions for the wave packet front propagation and recurrence are in good agreement with numeric simulations.

  19. Packet transfer delay analysis of the RPR rings in the store-and-forward architecture

    NASA Astrophysics Data System (ADS)

    Yang, Yi; Cao, Mingcui; Huang, Ping

    2005-02-01

    RRP has two means to transmit data: store-and-forward and cut-through. In this paper, the high and low priority packet transfer delay of the N nodes Resilient Packet Rings (RPR) in store-and-forward architecture is analyzed based on the queuing theory. According to queuing theory, we set up the nodes model and analyzed the factors that influenced the packet transfer delay in a constrained condition. By calculation and simulation, the result indicates that both high priority and low priority packets" delay increase with the node number N of the RPR rings. The high priority traffic has less packet delay than the low priority traffic at the same node number N. The increase of the low priority transfer delay is much larger than the high priority traffic with the increase of the node number.

  20. Dispatching packets on a global combining network of a parallel computer

    DOEpatents

    Almasi, Gheorghe; Archer, Charles J.

    2011-07-19

    Methods, apparatus, and products are disclosed for dispatching packets on a global combining network of a parallel computer comprising a plurality of nodes connected for data communications using the network capable of performing collective operations and point to point operations that include: receiving, by an origin system messaging module on an origin node from an origin application messaging module on the origin node, a storage identifier and an operation identifier, the storage identifier specifying storage containing an application message for transmission to a target node, and the operation identifier specifying a message passing operation; packetizing, by the origin system messaging module, the application message into network packets for transmission to the target node, each network packet specifying the operation identifier and an operation type for the message passing operation specified by the operation identifier; and transmitting, by the origin system messaging module, the network packets to the target node.

  1. Magnetic helicity conservation and inverse energy cascade in electron magnetohydrodynamic wave packets.

    PubMed

    Cho, Jungyeon

    2011-05-13

    Electron magnetohydrodynamics (EMHD) provides a fluidlike description of small-scale magnetized plasmas. An EMHD wave propagates along magnetic field lines. The direction of propagation can be either parallel or antiparallel to the magnetic field lines. We numerically study propagation of three-dimensional (3D) EMHD wave packets moving in one direction. We obtain two major results. (1) Unlike its magnetohydrodynamic (MHD) counterpart, an EMHD wave packet is dispersive. Because of this, EMHD wave packets traveling in one direction create opposite-traveling wave packets via self-interaction and cascade energy to smaller scales. (2) EMHD wave packets traveling in one direction clearly exhibit inverse energy cascade. We find that the latter is due to conservation of magnetic helicity. We compare inverse energy cascade in 3D EMHD turbulence and two-dimensional (2D) hydrodynamic turbulence.

  2. Source Authentication for Code Dissemination Supporting Dynamic Packet Size in Wireless Sensor Networks.

    PubMed

    Kim, Daehee; Kim, Dongwan; An, Sunshin

    2016-01-01

    Code dissemination in wireless sensor networks (WSNs) is a procedure for distributing a new code image over the air in order to update programs. Due to the fact that WSNs are mostly deployed in unattended and hostile environments, secure code dissemination ensuring authenticity and integrity is essential. Recent works on dynamic packet size control in WSNs allow enhancing the energy efficiency of code dissemination by dynamically changing the packet size on the basis of link quality. However, the authentication tokens attached by the base station become useless in the next hop where the packet size can vary according to the link quality of the next hop. In this paper, we propose three source authentication schemes for code dissemination supporting dynamic packet size. Compared to traditional source authentication schemes such as μTESLA and digital signatures, our schemes provide secure source authentication under the environment, where the packet size changes in each hop, with smaller energy consumption. PMID:27409616

  3. Source Authentication for Code Dissemination Supporting Dynamic Packet Size in Wireless Sensor Networks †

    PubMed Central

    Kim, Daehee; Kim, Dongwan; An, Sunshin

    2016-01-01

    Code dissemination in wireless sensor networks (WSNs) is a procedure for distributing a new code image over the air in order to update programs. Due to the fact that WSNs are mostly deployed in unattended and hostile environments, secure code dissemination ensuring authenticity and integrity is essential. Recent works on dynamic packet size control in WSNs allow enhancing the energy efficiency of code dissemination by dynamically changing the packet size on the basis of link quality. However, the authentication tokens attached by the base station become useless in the next hop where the packet size can vary according to the link quality of the next hop. In this paper, we propose three source authentication schemes for code dissemination supporting dynamic packet size. Compared to traditional source authentication schemes such as μTESLA and digital signatures, our schemes provide secure source authentication under the environment, where the packet size changes in each hop, with smaller energy consumption. PMID:27409616

  4. Scattering of intense laser radiation by a single-electron wave packet

    SciTech Connect

    Corson, John P.; Peatross, Justin; Mueller, Carsten; Hatsagortsyan, Karen Z.

    2011-11-15

    A quantum theoretical description of photoemission by a single laser-driven electron wave packet is presented. Energy-momentum conservation ensures that the partial emissions from individual momentum components of the electron wave packet do not interfere when the driving field is unidirectional. In other words, light scattering by an electron packet is independent of the phases of the pure momentum states comprising the packet; the size of the electron wave packet does not matter. This result holds also in the case of high-intensity multiphoton scattering. Our analysis is first presented in the QED framework. Since QED permits the second-quantized entangled electron-photon final state to be projected onto pure plane-wave states, the Born probability interpretation requires these projections to be first squared and then summed to find an overall probability of a scattering event. The QED treatment indicates how a semiclassical framework can be developed to recover the key features of the correct result.

  5. Interception and modification of network authentication packets with the purpose of allowing alternative authentication modes

    DOEpatents

    Kent, Alexander Dale

    2008-09-02

    Methods and systems in a data/computer network for authenticating identifying data transmitted from a client to a server through use of a gateway interface system which are communicately coupled to each other are disclosed. An authentication packet transmitted from a client to a server of the data network is intercepted by the interface, wherein the authentication packet is encrypted with a one-time password for transmission from the client to the server. The one-time password associated with the authentication packet can be verified utilizing a one-time password token system. The authentication packet can then be modified for acceptance by the server, wherein the response packet generated by the server is thereafter intercepted, verified and modified for transmission back to the client in a similar but reverse process.

  6. Non-intrusive Packet-Layer Model for Monitoring Video Quality of IPTV Services

    NASA Astrophysics Data System (ADS)

    Yamagishi, Kazuhisa; Hayashi, Takanori

    Developing a non-intrusive packet-layer model is required to passively monitor the quality of experience (QoE) during service. We propose a packet-layer model that can be used to estimate the video quality of IPTV using quality parameters derived from transmitted packet headers. The computational load of the model is lighter than that of the model that takes video signals and/or video-related bitstream information such as motion vectors as input. This model is applicable even if the transmitted bitstream information is encrypted because it uses transmitted packet headers rather than bitstream information. For developing the model, we conducted three extensive subjective quality assessments for different encoders and decoders (codecs), and video content. Then, we modeled the subjective video quality assessment characteristics based on objective features affected by coding and packet loss. Finally, we verified the model's validity by applying our model to unknown data sets different from training data sets used above.

  7. Flavor entanglement in neutrino oscillations in the wave packet description

    NASA Astrophysics Data System (ADS)

    Blasone, Massimo; Dell'Anno, Fabio; De Siena, Silvio; Illuminati, Fabrizio

    2015-10-01

    The wave packet approach to neutrino oscillations provides an enlightening description of quantum decoherence induced, during propagation, by localization effects. Within this approach, we show that a deeper insight into the dynamical aspects of particle mixing can be obtained if one investigates the behavior of quantum correlations associated to flavor oscillations. By identifying the neutrino three-flavor modes with (suitably defined) three-qubit modes, the exploitation of tools of quantum information theory for mixed states allows a detailed analysis of the dynamical behavior of flavor entanglement during free propagation. This provides further elements leading to a more complete understanding of the phenomenon of neutrino oscillations, and a basis for possible applicative implementations. The analysis is carried out by studying the distribution of the flavor entanglement; to this aim, we perform combined investigations of the behaviors of the two-flavor concurrence and of the logarithmic negativities associated with specific bipartitions of the three flavors.

  8. Improved wavelet packet compression of electrocardiogram data: 1. noise filtering

    NASA Astrophysics Data System (ADS)

    Bradie, Brian D.

    1995-09-01

    The improvement in the performance of a wavelet packet based compression scheme for single lead electrocardiogram (ECG) data, obtained by prefiltering noise from the ECG signals, is investigated. The removal of powerline interference and the attenuation of high-frequency muscle noise are considered. Selected records from the MIT-BIH Arrhythmia Database are used as test signals. After both types of noise artifact were filtered, an average data rate of 167.6 bits per second (corresponding to a compression ratio of 23.62), with an average root mean-square (rms) error of 15.886 (mu) V, was achieved. These figures represent better than a 9% improvement in data rate and a 13.5% reduction in rms error over compressing the unfiltered signals.

  9. Quantum oscillations and wave packet revival in conical graphene structure

    NASA Astrophysics Data System (ADS)

    Sinha, Debabrata; Berche, Bertrand

    2016-03-01

    We present analytical expressions for the eigenstates and eigenvalues of electrons confined in a graphene monolayer in which the crystal symmetry is locally modified by replacing a hexagon by a pentagon, square or heptagon. The calculations are performed in the continuum limit approximation in the vicinity of the Dirac points, solving Dirac equation by freezing out the carrier radial motion. We include the effect of an external magnetic field and show the appearance of Aharonov-Bohm oscillations and find out the conditions of gapped and gapless states in the spectrum. We show that the gauge field due to a disclination lifts the orbital degeneracy originating from the existence of two valleys. The broken valley degeneracy has a clear signature on quantum oscillations and wave packet dynamics.

  10. Silicon-Germanium Fast Packet Switch Developed for Communications Satellites

    NASA Technical Reports Server (NTRS)

    Quintana, Jorge A.

    1999-01-01

    Emerging multimedia applications and future satellite systems will require high-speed switching networks to accommodate high data-rate traffic among thousands of potential users. This will require advanced switching devices to enable communication between satellites. The NASA Lewis Research Center has been working closely with industry to develop a state-of-the-art fast packet switch (FPS) to fulfill this requirement. Recently, the Satellite Industry Task Force identified the need for high-capacity onboard processing switching components as one of the "grand challenges" for the satellite industry in the 21st century. In response to this challenge, future generations of onboard processing satellites will require low power and low mass components to enable transmission of services in the 100 gigabit (1011 bits) per second (Gbps) range.

  11. Hydrodynamic view of wave-packet interference: quantum caves.

    PubMed

    Chou, Chia-Chun; Sanz, Angel S; Miret-Artés, Salvador; Wyatt, Robert E

    2009-06-26

    Wave-packet interference is investigated within the complex quantum Hamilton-Jacobi formalism using a hydrodynamic description. Quantum interference leads to the formation of the topological structure of quantum caves in space-time Argand plots. These caves consist of the vortical and stagnation tubes originating from the isosurfaces of the amplitude of the wave function and its first derivative. Complex quantum trajectories display counterclockwise helical wrapping around the stagnation tubes and hyperbolic deflection near the vortical tubes. The string of alternating stagnation and vortical tubes is sufficient to generate divergent trajectories. Moreover, the average wrapping time for trajectories and the rotational rate of the nodal line in the complex plane can be used to define the lifetime for interference features. PMID:19659057

  12. Simulation of wave packet tunneling of interacting identical particles

    NASA Astrophysics Data System (ADS)

    Lozovik, Yu. E.; Filinov, A. V.; Arkhipov, A. S.

    2003-02-01

    We demonstrate a different method of simulation of nonstationary quantum processes, considering the tunneling of two interacting identical particles, represented by wave packets. The used method of quantum molecular dynamics (WMD) is based on the Wigner representation of quantum mechanics. In the context of this method ensembles of classical trajectories are used to solve quantum Wigner-Liouville equation. These classical trajectories obey Hamiltonian-like equations, where the effective potential consists of the usual classical term and the quantum term, which depends on the Wigner function and its derivatives. The quantum term is calculated using local distribution of trajectories in phase space, therefore, classical trajectories are not independent, contrary to classical molecular dynamics. The developed WMD method takes into account the influence of exchange and interaction between particles. The role of direct and exchange interactions in tunneling is analyzed. The tunneling times for interacting particles are calculated.

  13. Design and implementation considerations of a MSAT packet data network

    NASA Technical Reports Server (NTRS)

    Karam, Fouad G.; Hearn, Terry; Rohr, Doug; Guibord, Arthur F.

    1993-01-01

    The Mobile Data System, which is intended to provide for packet switched data services is currently under development. The system is based on a star network topology consisting of a centralized Data Hub (DH) serving a large number of mobile terminals. Through the Data Hub, end-to-end connections can be established between terrestrial users on public or private data networks and mobile users. The MDS network will be capable of offering a variety of services some of which are based on the standard X.25 network interface protocol, and others optimized for short messages and broadcast messages. A description of these services and the trade-offs in the DH design are presented.

  14. Active interface debonding detection of a concrete-filled steel tube with piezoelectric technologies using wavelet packet analysis

    NASA Astrophysics Data System (ADS)

    Xu, Bin; Zhang, Ting; Song, Gangbing; Gu, Haichang

    2013-03-01

    Concrete-Filled Steel Tube (CFST) has been widely adopted in high-rise buildings and bridges as a typical structural member carrying vertical loads in recent years. The debonding between the steel tube and the concrete can dramatically reduce the confinement effect of steel tube on the concrete and decrease the load-carrying capacity and the ductility of the CFST. It is still challenging to develop reliable debonding monitoring and detection techniques for CFST because of the inaccessibility of the interface. In this study, an active interface condition monitoring approach for CFST by the use of lead zirconate titanate (PZT) piezoceramics based functional smart aggregates (SAs) embedded in concrete as actuator and PZT patches bonded on the surface of the steel tube as sensors is proposed and verified experimentally. Laboratory tests are performed on the CFST column, in which the deboning is mimicked by setting four thin styrofoam plates with different sizes on different locations of the four internal surfaces of the steel tube, respectively, before casting the concrete. The responses of the PZT sensors are measured when each SA is excited with sweep sinusoidal signals. According to the Fourier spectra and two evaluation indices based on the wavelet packet analysis on the PZT sensors measurements, the artificially mimicked debonding areas are detected successfully. Analysis on the sensitivity of the two evaluation indices shows that the indices based on wavelet packet analysis are more sensitive to the debonding defect. The proposed PZT based active debonding monitoring method provides an innovative approach to detect the debonding damage of CFST columns.

  15. Arrival Time Distribution by the New Observation System at Taro

    NASA Astrophysics Data System (ADS)

    Sakuyama, H.; Obara, Hitoshi; Kuramochi, Hiroshi; Ono, Shunichi; Origasa, Satoru; Mochida, Akinori; Sakuyama, Hiroshi; Suzuki, Noboru

    2003-07-01

    The arrival time distribution of EAS has been observed by using Ultra Fast Cherenkov detector (UFC) and oscilloscope at Taro observatory since 1995 (sea level 200m). The EAS array is arranged 169 sets of 0.25m2 scintillation detectors in the shape of a lattice at intervals of 1.5m and about 40 scintillation detectors which consists of 1m2 and 0.25m2 is arranged in the peripheral part. Then, it consists of 8 fast timing detectors. The UFC detector is installed in the palce of about 20m from the trigger center. The observation system of a UFC detector was changed from the autumn of 2000. The outline of a new observation system and EAS arrival time distribution are reported.

  16. The arrival time distribution of EAS at Taro

    NASA Astrophysics Data System (ADS)

    Maeda, T.; Kuramochi, H.; Ono, S.; Sakuyama, H.; Suzuki, N.

    The arrival time distribution of EAS has been observed since 1995 at Taro cosmicray laboratory (200m above sea level). The EAS arrays consist of 1m2 and 0.25m2 scintillation detectors, 0.25m2 fast timing counters and ultra fast Cherenkov detectors (UFC). 169 0.25m2 scintillation detectors are arranged in alattice configuration with a unit distance of 1.5m. UFC is placed at 20m from the center of lattice array. The arrival time distribution has been analyzed with distance from EAS core (r=10-60m). One of the results shows that the radius of corvature increases as shower size (Ne), near to the EAS core.

  17. STS-93 Mission Specialist Coleman arrives at SLF for launch.

    NASA Technical Reports Server (NTRS)

    1999-01-01

    STS-93 Mission Specialist Catherine G. 'Cady' Coleman (Ph.D.) smiles upon her arrival at KSC's Shuttle Landing Facility aboard a T-38 jet aircraft. She and other crew members Commander Eileen Collins, Pilot Jeffrey S. Ashby, and Mission Specialists Steven A. Hawley (Ph.D.) and Michel Tognini of France, with the Centre National d'Etudes Spatiales (CNES), are arriving for pre-launch activities. Coleman is making her second Shuttle flight. The primary mission of STS-93 is the release of the Chandra X-ray Observatory, which will allow scientists from around the world to study some of the most distant, powerful and dynamic objects in the universe. The new telescope is 20 to 50 times more sensitive than any previous X-ray telescope and is expected to unlock the secrets of supernovae, quasars and black holes.

  18. Queuing model of a traffic bottleneck with bimodal arrival rate

    NASA Astrophysics Data System (ADS)

    Woelki, Marko

    2016-06-01

    This paper revisits the problem of tuning the density in a traffic bottleneck by reduction of the arrival rate when the queue length exceeds a certain threshold, studied recently for variants of totally asymmetric simple exclusion process (TASEP) and Burgers equation. In the present approach, a simple finite queuing system is considered and its contrasting “phase diagram” is derived. One can observe one jammed region, one low-density region and one region where the queue length is equilibrated around the threshold. Despite the simplicity of the model the physics is in accordance with the previous approach: The density is tuned at the threshold if the exit rate lies in between the two arrival rates.

  19. Expedition 4 crew member Daniel W. Bursch arrives at KSC

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Expedition 4 crew member Daniel W. Bursch arrives at KSC KSC-01PD-1705 KENNEDY SPACE CENTER, Fla. - Expedition 4 crew member Daniel W. Bursch arrives at KSC in a T-38 jet trainer. He and other crew members Commander Yuri Onufrienko and astronaut Carl E. Walz will be traveling on Space Shuttle Endeavour - mission STS-108 - to replace the Expedition 3 crew. Top priorities for the STS-108 (UF-1) mission of Endeavour are rotation of the International Space Station Expedition Three and Expedition Four crews, bringing water, equipment and supplies to the station in the Multi-Purpose Logistics Module Raffaello, and completion of spacewalk and robotics tasks. The mission crew comprises Commander Dominic L. Gorie, Pilot Mark E. Kelly and Mission Specialists Linda A. Godwin and Daniel M. Tani. Liftoff is scheduled for 7:41 p.m. EST..

  20. STS-108 Mission Specialist Daniel M. Tani arrives at KSC

    NASA Technical Reports Server (NTRS)

    2001-01-01

    STS-108 Mission Specialist Daniel M. Tani arrives at KSC KSC-01PD-1707 KENNEDY SPACE CENTER, Fla. -- STS-108 Mission Specialist Daniel M. Tani arrives at KSC in a T-38 jet trainer. He and the rest of the crew will be preparing for launch Nov. 29 on Space Shuttle Endeavour. Liftoff is scheduled for 7:41 p.m. EST. Top priorities for the STS-108 (UF-1) mission of Endeavour are rotation of the International Space Station Expedition Three and Expedition Four crews, bringing water, equipment and supplies to the station in the Multi-Purpose Logistics Module Raffaello, and completion of spacewalk and robotics tasks. Mission Specialists Linda A. Godwin and Tani will take part in the spacewalk to install thermal blankets over two pieces of equipment at the bases of the Space Station's solar wings. Other crew members are Commander Dominic L. Gorie and Pilot Mark E. Kelly.

  1. Arrival condition of spent fuel after storage, handling, and transportation

    SciTech Connect

    Bailey, W.J.; Pankaskie, P.J.; Langstaff, D.C.; Gilbert, E.R.; Rising, K.H.; Schreiber, R.E.

    1982-11-01

    This report presents the results of a study conducted to determine the probable arrival condition of spent light-water reactor (LWR) fuel after handling and interim storage in spent fuel storage pools and subsequent handling and accident-free transport operations under normal or slightly abnormal conditions. The objective of this study was to provide information on the expected condition of spent LWR fuel upon arrival at interim storage or fuel reprocessing facilities or at disposal facilities if the fuel is declared a waste. Results of a literature survey and data evaluation effort are discussed. Preliminary threshold limits for storing, handling, and transporting unconsolidated spent LWR fuel are presented. The difficulty in trying to anticipate the amount of corrosion products (crud) that may be on spent fuel in future shipments is also discussed, and potential areas for future work are listed. 95 references, 3 figures, 17 tables.

  2. STS-84 Pilot Collins arrives at SLF prior to launch

    NASA Technical Reports Server (NTRS)

    1997-01-01

    STS-84 Pilot Eileen Marie Collins arrives in a T-38 jet at KSCs Shuttle Landing Facility. Collins will make her second space flight on STS-84. Her initial flight was as the first woman Shuttle pilot on STS-63 in 1995. STS-84 will be the sixth docking of the Space Shuttle with the Russian Space Station Mir. During the docking, STS-84 Mission Specialist C. Michael Foale will transfer to the Russian space station to become a member of the Mir 23 crew, replacing U.S. astronaut Jerry M. Linenger, who will return to Earth on Atlantis. Foale is scheduled to remain on Mir about four months until his replacement arrives on STS-86 in September.

  3. STS-86 Mission Specialist Chretien arrives at SLF before launch

    NASA Technical Reports Server (NTRS)

    1997-01-01

    STS-86 Mission Specialist Jean-Loup J.M. Chretien of the French Space Agency, CNES, arrives at KSCs Shuttle Landing Facility for the final prelaunch activities leading up to the scheduled Sept. 25 liftoff. This will be Chretiens third spaceflight, but first on the Space Shuttle. He is chief of the Astronaut Office of CNES. STS-86 is slated to be the seventh of nine planned dockings of the Space Shuttle with the Russian Space Station Mir.

  4. Community assembly in experimental grasslands: suitable environment or timely arrival?

    PubMed

    Ejrnaes, Rasmus; Bruun, Hans Henrik; Graae, Bente J

    2006-05-01

    It is hard to defend the view that biotic communities represent a simple and predictable response to the abiotic environment. Biota and the abiotic environment interact, and the environment of an individual certainly includes its neighbors and visitors in the community. The complexity of community assembly calls forth a quest for general principles, yet current results and theories on assembly rules differ widely. Using a grassland microcosm as a model system, we manipulated fertility, disturbance by defoliation, soil/microclimate, and arrival order of species belonging to two groups differing in functional attributes. We analyzed the outcome of community assembly dynamics in terms of species richness, invasibility, and species composition. The analyses revealed strong environmental control over species richness and invasibility. Species composition was mainly determined by the arrival order of species, indicating that historical contingency may change the outcome of community assembly. The probability for multiple equilibria appeared to increase with productivity and environmental stability. The importance of arrival order offers an explanation of the difficulties in predicting local occurrences of species in the field. In our experiment, variation in fertility and disturbance was controlling colonization with predictable effects on emergent community properties such as species richness. The key mechanism is suggested to be asymmetric competition, and our results show that this mechanism is relatively insensitive to the species through which it works. While our analyses indicate a positive and significant correlation between richness and invasibility, the significance disappears after accounting for the effect of the environment. The importance of arrival order (historical contingency) and environmental control supports the assumption of the unified neutral theory that different species within a trophic level can be considered functionally equivalent when it comes

  5. STS-80 Crew Arrival (Mission Specialist Story Musgrave)

    NASA Technical Reports Server (NTRS)

    1996-01-01

    STS-80 Mission Specialist Story Musgrave and four fellow crew members arrive at KSC's Shuttle Landing Facility as preparations continue for launch of the final Shuttle flight of 1996. Tomorrow, Nov. 12, the launch countdown will begin at 1 p.m. with the countdown clock set at T-43 hours. The Space Shuttle Columbia is scheduled for liftoff from Launch Pad 39B at 2:50 p.m. EST, Nov. 15.

  6. STS-104 MS Reilly arrives at the SLF before launch

    NASA Technical Reports Server (NTRS)

    2001-01-01

    KENNEDY SPACE CENTER, Fla. -- STS-104 Mission Specialist James F. Reilly arrives at the KSC Shuttle Landing Facility to make final preparations for launch of Space Shuttle Atlantis July 12. The mission is the 10th assembly flight to the International Space Station and carries the Joint Airlock Module, which will become the primary path for spacewalk entry and departure using both U.S. spacesuits and the Russian Orlan spacesuit for EVA activity.

  7. STS-104 MS Kavandi arrives at the SLF before launch

    NASA Technical Reports Server (NTRS)

    2001-01-01

    KENNEDY SPACE CENTER, Fla. -- STS-104 Mission Specialist Janet Lynn Kavandi arrives at the KSC Shuttle Landing Facility to make final preparations for launch of Space Shuttle Atlantis July 12. The mission is the 10th assembly flight to the International Space Station and carries the Joint Airlock Module, which will become the primary path for spacewalk entry and departure using both U.S. spacesuits and the Russian Orlan spacesuit for EVA activity.

  8. STS-104 MS Gernhardt arrives at the SLF before launch

    NASA Technical Reports Server (NTRS)

    2001-01-01

    KENNEDY SPACE CENTER, Fla. -- STS-104 Mission Specialist Michael L. Gernhardt arrives at the KSC Shuttle Landing Facility to make final preparations for launch of Space Shuttle Atlantis July 12. The mission is the 10th assembly flight to the International Space Station and carries the Joint Airlock Module, which will become the primary path for spacewalk entry and departure using both U.S. spacesuits and the Russian Orlan spacesuit for EVA activity.

  9. Crewmen of the Gemini 7 spacecraft arrive aboard aircraft carrier

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Astronauts James A. Lovell Jr., (left), pilot, and Frank Borman, command pilot, are shown just after they arrived aboard the aircraft carrier U.S.S. Wasp. Greeting the astronauts are Donald Stullken (at Lovell's right), Recovery Operations Branch, Landing and Recovery Division; Dr. Howard Minners (standing beside Borman), Flight Medicine Branch, Cneter Medical Office, Manned Spacecraft Center, and Bennett James (standing behind Borman), a NASA Public Affairs Officer.

  10. STS-79 Atlantis arrives at LC39A

    NASA Technical Reports Server (NTRS)

    1996-01-01

    The Space Shuttle Atlantis arrives at Launch Pad 39A at twilight. The second rollout to the pad brings Atlantis one step closer to a launch scheduled around September 12. Mission STS-79 will be highlighted by the fourth docking between the U.S. Space Shuttle and the Russian Space Station Mir, and the return to Earth of U.S. astronaut Shannon Lucid after a record-setting stay aboard the station

  11. Apollo 10 crewmembers arrive aboard U.S.S. Princeton

    NASA Technical Reports Server (NTRS)

    1969-01-01

    The Apollo 10 crewmembers arrive aboard the U.S.S. Princeton as they step from a helicopter to receive a red carpet welcome. Left to right, are Astronauts Eugene A. Cernan, lunar module pilot; Thomas P. Stafford, commander; and John W. Young, command module pilot. Standing in left foreground is Dr. Donald E. Stullken, Chief, Recovery Operations Branch, Landing and Recovery Division, Manned Spacecraft Center.

  12. Evaluating predictions of ICME arrival at Earth and Mars

    NASA Astrophysics Data System (ADS)

    Falkenberg, T. V.; Taktakishvili, A.; Pulkkinen, A.; Vennerstrom, S.; Odstrcil, D.; Brain, D.; Delory, G.; Mitchell, D.

    2011-09-01

    We present a study of interplanetary coronal mass ejection (ICME) propagation to Earth and Mars. Because of the significant space weather hazard posed by ICMEs, understanding and predicting their arrival and impact at Mars is important for current and future robotic and manned missions to the planet. We compare running ENLILv2.6 with coronal mass ejection (CME) input parameters from both a manual and an automated method. We analyze shock events identified at Mars in Mars Global Surveyor data in 2001 and 2003, when Earth and Mars were separated by <80° in heliocentric longitude. The shocks identified at Mars were also identified at Earth, and the majority of the shock sources were identified through the Solar and Heliospheric Observatory-Large Angle and Spectrometric Coronagraph catalogue. We find that arrival times predicted by the two methods at both planets are statistically similar, dynamic pressures predicted when using the automated method are better, and the automated method tends to underestimate both CME width and speed. Using the location of the related flare as the CME direction did not improve results. In addition, changing the CME speed toward the plane-of-sky speed at 20 RS improves the match to observations, mainly because the speed found by the automated method is underestimated. The time lapse between the shock arrival at Earth and Mars, for the events studied here, is shorter than expected from simulations, and the presence of high speed streams can enable an ICME to arrive almost simultaneously at Earth and Mars. This work will be applied to improve the input parameter methods for ENLIL.

  13. Community assembly in experimental grasslands: suitable environment or timely arrival?

    PubMed

    Ejrnaes, Rasmus; Bruun, Hans Henrik; Graae, Bente J

    2006-05-01

    It is hard to defend the view that biotic communities represent a simple and predictable response to the abiotic environment. Biota and the abiotic environment interact, and the environment of an individual certainly includes its neighbors and visitors in the community. The complexity of community assembly calls forth a quest for general principles, yet current results and theories on assembly rules differ widely. Using a grassland microcosm as a model system, we manipulated fertility, disturbance by defoliation, soil/microclimate, and arrival order of species belonging to two groups differing in functional attributes. We analyzed the outcome of community assembly dynamics in terms of species richness, invasibility, and species composition. The analyses revealed strong environmental control over species richness and invasibility. Species composition was mainly determined by the arrival order of species, indicating that historical contingency may change the outcome of community assembly. The probability for multiple equilibria appeared to increase with productivity and environmental stability. The importance of arrival order offers an explanation of the difficulties in predicting local occurrences of species in the field. In our experiment, variation in fertility and disturbance was controlling colonization with predictable effects on emergent community properties such as species richness. The key mechanism is suggested to be asymmetric competition, and our results show that this mechanism is relatively insensitive to the species through which it works. While our analyses indicate a positive and significant correlation between richness and invasibility, the significance disappears after accounting for the effect of the environment. The importance of arrival order (historical contingency) and environmental control supports the assumption of the unified neutral theory that different species within a trophic level can be considered functionally equivalent when it comes

  14. NOAA-L satellite arrives at Vandenberg AFB

    NASA Technical Reports Server (NTRS)

    2000-01-01

    A crated National Oceanic and Atmospheric Administration (NOAA-L) satellite arrives at Vandenberg Air Force Base, Calif. It is part of the Polar-Orbiting Operational Environmental Satellite (POES) program that provides atmospheric measurements of temperature, humidity, ozone and cloud images, tracking weather patterns that affect the global weather and climate. The launch of the NOAA-L satellite is scheduled no earlier than Sept. 12 aboard a Lockheed Martin Titan II rocket. STS-69 Pilot Kenneth D. Cockrell arrives at SLF

    NASA Technical Reports Server (NTRS)

    1995-01-01

    STS-69 Pilot Kenneth D. Cockrell arrives at KSC's Shuttle Landing Facility. Cockrell and four fellow crew members flew in from Johnson Space Center, Houston, in the T-38 jet aircraft traditionally used by the astronaut corps. Later today, the countdown will begin as final preparations continue toward liftoff of the Space Shuttle Endeavour at ll:04 a.m. EDT, Aug. 31, on STS-69.

  15. Does the arrival index predict physiological stress reactivity in children.

    PubMed

    de Veld, Danielle M J; Riksen-Walraven, J Marianne; de Weerth, Carolina

    2014-09-01

    Knowledge about children's stress reactivity and its correlates is mostly based on one stress task, making it hard to assess the generalizability of the results. The development of an additional stress paradigm for children, that also limits stress exposure and test time, could greatly advance this field of research. Research in adults may provide a starting point for the development of such an additional stress paradigm, as changes in salivary cortisol and alpha-amylase (sAA) over a 1-h pre-stress period in the laboratory correlated strongly with subsequent reactivity to stress task (Balodis et al., 2010, Psychoneuroendocrinology 35:1363-73). The present study examined whether such strong correlations could be replicated in 9- to 11-year-old children. Cortisol and sAA samples were collected from 158 children (83 girls) during a 2.5-h visit to the laboratory. This visit included a 1-h pre-stress period in which children performed some non-stressful tasks and relaxed before taking part in a psychosocial stress task (TSST-C). A higher cortisol arrival index was significantly and weakly correlated with a higher AUCg but unrelated to cortisol reactivity to the stressor. A higher sAA arrival index was significantly and moderately related to lower stress reactivity and to a lower AUCi. Children's personality and emotion regulation variables were unrelated to the cortisol and sAA arrival indices. The results of this study do not provide a basis for the development of an additional stress paradigm for children. Further replications in children and adults are needed to clarify the potential meaning of an arrival index.

  16. A study of the arrival direction using Offline

    SciTech Connect

    Flores, Alejandra Parra; Bravo, Oscar Martinez; Ibargueen, Humberto Salazar; Aguilar, Ibrahim Torres

    2009-04-30

    The purpose of this work is to show the results of the analysis of a library of synthetic data corresponding to Very Inclined Showers (i.e. those with a zenith angle between 60 and 80 degrees and energies from 50 EeV to 80 EeV). Simulations were performed using the Aires software and then analyzed to narrow down the arrival angles that allow us an efficient shower reconstruction using the Offline software.

  17. Iterative direction-of-arrival estimation with wideband chirp signals

    NASA Astrophysics Data System (ADS)

    Wang, Genyuan; Xia, Xiang-Gen; Chen, Victor C.

    1999-11-01

    Amin et. al. recently developed a time-frequency MUSIC algorithm with narrow band models for the estimation of direction of arrival (DOA) when the source signals are chirps. In this research, we consider wideband models. The joint time-frequency analysis is first used to estimate the chirp rates of the source signals and then the DOA is estimated by the MUSIC algorithm with an iterative approach.

  18. Group foraging by a stream minnow: shoals or aggregations?

    USGS Publications Warehouse

    Freeman, Mary C.; Grossman, G.D.

    1992-01-01

    The importance of social attraction in the formation of foraging groups was examined for a stream-dwelling cyprinid, the rosyside dace, Clinostomus funduloides. Dace arrivals and departures at natural foraging sites were monitored and tested for (1) tendency of dace to travel in groups, and (2) dependency of arrival and departure rates on group size. Dace usually entered and departed foraging sites independently of each other. Group size usually affected neither arrival rate nor departure probability. Thus, attraction among dace appeared weak; foraging groups most often resulted from dace aggregating in preferred foraging sites. The strongest evidence of social attraction was during autumn, when dace departure probability often decreased with increasing group size, possibly in response to increased threat of predation by a seasonally occurring predator. Dace also rarely avoided conspecifics, except when an aggressive individual defended a foraging site. Otherwise, there was little evidence of exploitative competition among dace for drifting prey or of foraging benefits in groups, because group size usually did not affect individual feeding rates. These results suggest that the benefits of group foraging demonstrated under laboratory conditions in other studies may not always apply to field conditions.

  19. Self-regulation in newly arrived international adoptees.

    PubMed

    Tirella, Linda Grey; Miller, Laurie C

    2011-08-01

    Many newly arrived international adoptees (IA) have difficulties with eating, sleeping, and self-soothing/self-stimulating (SS) behaviors. However, to date the prevalence of these problems and associated risk factors have not been clearly identified. Therefore, we proposed to evaluate 387 IA for the presence of these self-regulation and behavioral difficulties, and examined the relationships between these behaviors and pre-adoptive risk factors including growth measures, orphanage care, age at arrival and presence of medical complications. Data on participants were collected in a retrospective chart review and entered into a standardized data collection sheet by a trained research assistant. This exploratory study included 133 M and 254 F with an average age (M = 16) months at the time of the study. Children in the study represented adoptees from seventeen countries. Forty-nine per cent (49%) of the retrospective sample exhibited SS behaviors, 48% had sleep disturbances, and 34% had eating issues. Many had difficulties in more than one area. Country of origin, pre-adoption residence, and arrival nutritional status all related to the presence of these problems. Hence, self-regulation difficulties are common but both the course and influence of those behaviors on family functioning remains unknown.