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Sample records for activity packets ecaps

  1. 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…

  2. 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…

  3. 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…

  4. 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…

  5. 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.…

  6. 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…

  7. 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…

  8. Influence of thermally activated processes on the deformation behavior during low temperature ECAP

    NASA Astrophysics Data System (ADS)

    Fritsch, S.; Scholze, M.; F-X Wagner, M.

    2016-03-01

    High strength aluminum alloys are generally hard to deform. Therefore, the application of conventional severe plastic deformation methods to generate ultrafine-grained microstructures and to further increase strength is considerably limited. In this study, we consider low temperature deformation in a custom-built, cooled equal channel angular pressing (ECAP) tool (internal angle 90°) as an alternative approach to severely plastically deform a 7075 aluminum alloy. To document the maximum improvement of mechanical properties, these alloys are initially deformed from a solid solution heat-treated condition. We characterize the mechanical behavior and the microstructure of the coarse grained initial material at different low temperatures, and we analyze how a tendency for the PLC effect and the strain-hardening rate affect the formability during subsequent severe plastic deformation at low temperatures. We then discuss how the deformation temperature and velocity influence the occurrence of PLC effects and the homogeneity of the deformed ECAP billets. Besides the mechanical properties and these microstructural changes, we discuss technologically relevant processing parameters (such as pressing forces) and practical limitations, as well as changes in fracture behavior of the low temperature deformed materials as a function of deformation temperature.

  9. 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…

  10. 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…

  11. 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…

  12. 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…

  13. 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…

  14. 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…

  15. 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…

  16. 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…

  17. Ultrasonic assisted-ECAP.

    PubMed

    Djavanroodi, F; Ahmadian, H; Koohkan, K; Naseri, R

    2013-08-01

    Equal channel angular pressing (ECAP) is one of the most prominent procedures for achieving ultra-fine grain (UFG) structures among the various severe plastic deformation (SPD) techniques. In this study, the effect of ultrasonic vibration on deformation behavior of commercial pure aluminum in the ECAP process is analyzed successfully using three dimensional (3D) by finite element methods (FEMs). The investigation includes the effects of die geometry, billet length, friction factor, ram speed, ultrasonic amplitude and ultrasonic frequency. Conventional as well as ultrasonic ECAP has been performed on aluminium 1070 alloy and the obtained data were used for validating simulations. It is observed that a 13% reduction in the average force was achieved when ultrasonic vibration with amplitude of 2.5 μm at 20 kHz is applied. Also, further reduction in ECAP forming forces are obtained with increase of vibration amplitude, vibration frequency, friction factor, billet length and die channel angle.

  18. 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)

  19. 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…

  20. 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…

  1. [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…

  2. 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…

  3. 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)…

  4. 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.

  5. 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…

  6. 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…

  7. 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…

  8. Home Economics. Iowa Developed Energy Activity Sampler, 6-12. Revised.

    ERIC Educational Resources Information Center

    Iowa State Dept. of Education, Des Moines. Div. of Instructional Services.

    The revised Iowa Developed Energy Activity Sampler (IDEAS) was compiled using the original IDEAS program and the Energy Conservation Activity Packets (ECAPS). This document was developed to provide home economics teachers with background information on energy, and activities that can be used/adapted with a minimum of preparation time. The…

  9. Can ECAP measures be used for totally objective programming of cochlear implants?

    PubMed

    McKay, Colette M; Chandan, Kirpa; Akhoun, Idrick; Siciliano, Catherine; Kluk, Karolina

    2013-12-01

    An experiment was conducted with eight cochlear implant subjects to investigate the feasibility of using electrically evoked compound action potential (ECAP) measures other than ECAP thresholds to predict the way that behavioral thresholds change with rate of stimulation, and hence, whether they can be used without combination with behavioral measures to determine program stimulus levels for cochlear implants. Loudness models indicate that two peripheral neural response characteristics contribute to the slope of the threshold versus rate function: the way that neural activity to each stimulus pulse decreases as rate increases and the slope of the neural response versus stimulus current function. ECAP measures related to these two characteristics were measured: the way that ECAP amplitude decreases with stimulus rate and the ECAP amplitude growth function, respectively. A loudness model (incorporating temporal integration and the two neural response characteristics) and regression analyses were used to evaluate whether the ECAP measures could predict the average slope of the behavioral threshold versus current function and whether individual variation in the measures could predict individual variation in the slope of the threshold function. The average change of behavioral threshold with increasing rate was well predicted by the model when using the average ECAP data. However, the individual variations in the slope of the thresholds versus rate functions were not well predicted by individual variations in ECAP data. It was concluded that these ECAP measures are not useful for fully objective programming, possibly because they do not accurately reflect the neural response characteristics assumed by the model, or are measured at current levels much higher than threshold currents.

  10. Slow-light Airy wave packets and their active control via electromagnetically induced transparency

    NASA Astrophysics Data System (ADS)

    Hang, Chao; Huang, Guoxiang

    2013-07-01

    We propose a scheme to generate (3+1)-dimensional slow-light Airy wave packets in a resonant Λ-type three-level atomic gas via electromagnetically induced transparency. We show that in the absence of dispersion the Airy wave packets formed by a probe field consist of two Airy wave packets accelerated in transverse directions and a longitudinal Gaussian pulse with a constant propagating velocity lowered to 10-5c (c is the light speed in vacuum). We also show that in the presence of dispersion it is possible to generate another type of slow-light Airy wave packet consisting of two Airy beams in transverse directions and an Airy wave packet in the longitudinal direction. In this case, the longitudinal velocity of the Airy wave packet can be further reduced during propagation. Additionally, we further show that the transverse accelerations (or bending) of the both types of slow-light Airy wave packets can be completely eliminated and the motional trajectories of them can be actively manipulated and controlled by using a Stern-Gerlach gradient magnetic field.

  11. Electronic Compliance and Approval Project (ECAP)

    SciTech Connect

    Morgan, Hope; Varela, Richard A.; LaHood, Deborah; Cisco, Susan; Benavides, Mary Ann; Burks, Donna

    2002-03-20

    The Texas Railroad Commission (RRC), working in partnership with the United States Department of Energy and the oil and gas industry it regulates, implemented a strategy for improving efficiency in regulations and significantly reducing administrative operating costs through the Electronic Compliance and Approval Process (ECAP). This project streamlined regulatory compliance and reporting by providing the ability to electronically submit, process, and query oil and gas applications and reports through the Internet-based ECAP system.

  12. Learning Activity Packets for Grinding Machines. Unit II--Surface Grinding.

    ERIC Educational Resources Information Center

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

    This learning activity packet (LAP) is one of three that accompany the curriculum guide on grinding machines. It outlines the study activities and performance tasks for the second unit of this curriculum guide. Its purpose is to aid the student in attaining a working knowledge of this area of training and in achieving a skilled or moderately…

  13. Learning Activity Packets for Grinding Machines. Unit I--Grinding Machines.

    ERIC Educational Resources Information Center

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

    This learning activity packet (LAP) is one of three that accompany the curriculum guide on grinding machines. It outlines the study activities and performance tasks for the first unit of this curriculum guide. Its purpose is to aid the student in attaining a working knowledge of this area of training and in achieving a skilled or moderately…

  14. French-Canadians, Acadians and the French in New England. A Learning Activity Packet.

    ERIC Educational Resources Information Center

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

    The history of the French-Canadians from their beginnings to the present time is the topic of this Learning Activity Packet (LAP). Designed to acquaint students with the French, Canada's earliest permanent settlers following the Indians, the unit is divided into six objectives which include learning activities for each. Students are expected to…

  15. Auto Mechanics I. Learning Activity Packets (LAPs). Section C--Engine.

    ERIC Educational Resources Information Center

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

    This document contains five learning activity packets (LAPs) that outline the study activities for the "engine" instructional area for an Auto Mechanics I course. The five LAPs cover the following topics: basic engine principles, cooling system, engine lubrication system, exhaust system, and fuel system. Each LAP contains a cover sheet that…

  16. Learning Activity Packets for Auto Mechanics II. Section A--Engine Rebuilding.

    ERIC Educational Resources Information Center

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

    Eight learning activity packets (LAPs) are provided for the instructional area of engine rebuilding in the auto mechanics II program. They accompany an instructor's guide available separately. The LAPs outline the study activities and performance tasks for these eight units: (1) engine condition evaluation; (2) engine removal; (3) engine…

  17. Learning Activity Packets for Auto Mechanics II. Section C--Drive Train.

    ERIC Educational Resources Information Center

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

    Five learning activity packets (LAPs) are provided for the instructional area of drive train in the auto mechanics II program. They accompany an instructor's guide available separately. The LAPs outline the study activities and performance tasks for these five units: (1) clutch assembly, (2) standard transmission, (3) drive lines, (4) rear axle,…

  18. Auto Mechanics I. Learning Activity Packets (LAPs). Section A--Orientation and Safety.

    ERIC Educational Resources Information Center

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

    This document contains seven learning activity packets (LAPs) that outline the study activities for the orientation and safety instructional area for an Auto Mechanics I course. The seven LAPs cover the following topics: orientation, safety, hand tools, arc welding, oxyacetylene cutting, oxyacetylene fusion welding, and oxyacetylene braze welding.…

  19. The Atlantic Canada-New England Region and Environment. A Learning Activity Packet.

    ERIC Educational Resources Information Center

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

    In this Learning Activity Packet (LAP) students examine the geographic and ecological bases of the Eastern international region. The overall objective of activities is to help students comprehend the man-earth relationship concept. By studying this familiar relevant region students gain geographic knowledge and skills applicable to other areas.…

  20. Learning Activity Packets for Milling Machines. Unit III--Vertical Milling Machines.

    ERIC Educational Resources Information Center

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

    This learning activity packet (LAP) outlines the study activities and performance tasks covered in a related curriculum guide on milling machines. The course of study in this LAP is intended to help students learn to set up and operate a vertical mill. Tasks addressed in the LAP include mounting and removing cutters and cutter holders for vertical…

  1. Learning Activity Packets for Milling Machines. Unit II--Horizontal Milling Machines.

    ERIC Educational Resources Information Center

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

    This learning activity packet (LAP) outlines the study activities and performance tasks covered in a related curriculum guide on milling machines. The course of study in this LAP is intended to help students learn to set up and operate a horizontal mill. Tasks addressed in the LAP include mounting style "A" or "B" arbors and adjusting arbor…

  2. Learning Activity Packets for Milling Machines. Unit I--Introduction to Milling Machines.

    ERIC Educational Resources Information Center

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

    This learning activity packet (LAP) outlines the study activities and performance tasks covered in a related curriculum guide on milling machines. The course of study in this LAP is intended to help students learn to identify parts and attachments of vertical and horizontal milling machines, identify work-holding devices, state safety rules, and…

  3. Time Management. Office Occupations. Audiovisual Package. Instructor's Guide. Student Activity Packet.

    ERIC Educational Resources Information Center

    Johnson, Diane E.

    This instructor's guide and student activity packet (together with a slide/tape presentation not available here) comprise a module for the postsecondary office occupations education competency area of time management. Modules for other competency areas are available separately. The purpose stated for the module is to help students obtain basic…

  4. Curriculum Development of Learning Activity Packets, Dental Assisting Program. Final Report.

    ERIC Educational Resources Information Center

    Hempler, Nancy A.

    A dental assisting instructor was provided with 250 hours of released time to develop standardized Learning Activity Packets (LAPs) for the Dental Assisting program at the Bellingham (Washington) Vocational Technical Institute. The instructor reviewed unit objectives, gathered input from local dental professionals, reviewed reference materials,…

  5. Viva Nuestra Amistad IV: Spanish Activity Packet (Long Live our Friendship).

    ERIC Educational Resources Information Center

    Cobb, Hubert

    This Spanish activity packet was designed to be used with the map study portion of each of twelve units in a second year course in Spanish. Each unit deals with a different Spanish-speaking country or place, such as Puerto Rico, Colombia, Venezuela, or Peru. Included here are worksheets, games, map outlines, crossword puzzles, skits, and cultural…

  6. Math Skills for Business. 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 math skills for business. Included in the instructor's guide are general directions for implementing the presentation; a detailed guide for teaching the lesson that includes performance objectives,…

  7. ELECTRONIC COMPLIANCE AND APPROVAL PROJECT (ECAP)

    SciTech Connect

    Hope Morgan; Richard A. Varela; Deborah LaHood; Susan Cisco; Mary Ann Benavides; Donna Burks

    2002-11-01

    The Texas Railroad Commission (RRC), working in partnership with the United States Department of Energy and the oil and gas industry it regulates, is implementing a strategy for improving efficiency in regulations and significantly reducing administrative operating costs through the Electronic Compliance and Approval Process (ECAP). The project will streamline regulatory compliance and reporting by providing the ability to electronically submit, process, and query oil and gas applications and reports through the Internet-based ECAP system. Implementation of an ECAP drilling permit pilot project began September 1999 after funding resources were secured--a $700,000 grant from the U.S. Department of Energy and an appropriation of $1.4 million from the Texas Legislature. The pilot project involves creating the ability to file, review, and approve a well's drilling permit application through a completely electronic process. The pilot project solution will ultimately provide the infrastructure, technology, and electronic modules to enable the filing of all compliance permits and performance reports through the internet from a desktop computer. The pilot project was conducted in three phases. The first phase, implemented May 2000, provided the infrastructure that allows the electronic filing and approval of simple drilling permit applications, associated fees, and attachments. The official ''roll-out'' of ECAP and the first electronically filed drilling permit application occurred on May 11, 2000 in Dallas in conjunction with an Internet Workshop sponsored by the Petroleum Technology Transfer Council. After the completion of Phase I, the ECAP team conducted an extensive review of progress to date and analyzed requirements and opportunities for future steps. The technical team identified core infrastructure modifications that would facilitate and better support future development and expansion of the ECAP system and work began on database structure modifications. The

  8. Wind in the Willows--Theatre Activity Packet.

    ERIC Educational Resources Information Center

    New York City Board of Education, Brooklyn, NY. Div. of Curriculum and Instruction.

    Part of the New York City Board of Education's Early Stages program, and intended for elementary and secondary school teachers who wish to include a unit on theater in their classes, this guide offers suggestions for lessons and activities to accompany viewing a performance of "Wind in the Willows" at the Nederlander Theater. Part one of the guide…

  9. 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…

  10. Recognizing Proofreaders' Marks and Using Them in Editing. Audiovisual Package. Instructor's Guide [and] Student Activity Packet. Office Occupations.

    ERIC Educational Resources Information Center

    Johnson, Diane E.

    Designed for use with 38 full-color slides and a cassette tape presentation, this instructional package consists of an instructor's guide and a student activity packet. The instructor's guide includes general instructions for presenting the instructional unit as well as specific instructions for introducing, implementing, and evaluating student…

  11. 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…

  12. Evaluation of microstructure anisotropy on room and medium temperature ECAP deformed F138 steel

    SciTech Connect

    De Vincentis, N.S.; Kliauga, A.; Ferrante, M.; Avalos, M.; Brokmeier, H.-G.; Bolmaro, R.E.

    2015-09-15

    The microstructure developed during severe plastic deformation results in improved mechanical properties because of the decrease in domain sizes and accumulation of defects, mainly dislocation arrays. The characteristic deformation stages observed in low stacking fault energy (SFE) face centered cubic (FCC) materials are highly influenced by the development of the primary and secondary twinning that compete with dislocation glide. In this paper, a low SFE F138 stainless steel is deformed by equal channel angular pressing (ECAP) up to 4 passes at room temperature (RT) and at 300 °C to compare the grain refinement and twin boundary development with increasing deformation. Tensile tests were performed to determine the deformation stages reached by the material before and after ECAP deformation, and the resulting microstructure was observed by TEM. X-ray diffraction and EBSD, average technique the first and local the second one, were used to quantify the microstructural changes, allowing the determination of diffraction domain sizes, dislocation and stacking fault densities and misorientation indices, which lead to a complete analysis of the deformation introduced in the material, with comparative correlations between various microstructural parameters. - Highlights: • The microstructure of ECAP pressed F138 steel was studied using TEM, EBSD and XRD. • Increasing deformation reduced domain sizes and increased dislocation densities. • Dislocation array compactness and misorientation increased with higher deformation. • Largest dislocation densities, mostly screw, match with simultaneous activation of twins. • Several correlations among microstructural features and parameters have been disclosed.

  13. Thermal Response on the Microstructure and Texture of ECAP and Cold-Rolled Pure Magnesium

    NASA Astrophysics Data System (ADS)

    Biswas, Somjeet; Singh, D. Satyaveer; Beausir, Benoît; Toth, Laszlo S.; Suwas, Satyam

    2015-06-01

    This paper deals with dynamic recrystallization (DRX), static recrystallization, and grain growth phenomena of pure magnesium after equal channel angular pressing (ECAP) by route A and BC at 523 K (250 °C) followed by 80 pct cold rolling. The ECAP-deformed and the subsequently rolled samples were annealed at 373 K and 773 K (100 °C and 500 °C). The associated changes in the microstructure and texture were studied using electron back-scattered diffraction. ECAP produced an average grain size of ~12 to 18 µm with B and C2 fiber textures. Subsequent rolling led to an average grain size ~8 to 10 µm with basal texture fiber parallel to ND. There was no noticeable increase in the average grain size on annealing at 373 K (100 °C). However, significant increase in the average grain size occurred at 773 K (500 °C). The occurrence of different DRX mechanisms was detected: discontinuous dynamic recrystallization was attributed to basal slip activity and continuous dynamic recovery and recrystallization to prismatic/pyramidal slip systems. Only continuous static recrystallization could be observed on annealing.

  14. 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…

  15. 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…

  16. A Modification on ECAP Process by Incorporating Twist Channel

    NASA Astrophysics Data System (ADS)

    Bisadi, Hosein; Mohamadi, Mehdi Rezazadeh; Miyanaji, Hadi; Abdoli, Maryam

    2013-03-01

    In this study, a method that combines the equal channel angular pressing (ECAP) and twist extrusion (TE) techniques has been introduced as a severe plastic deformation process and investigated by means of the three-dimensional finite element analysis. Owing to the form of the mold which is used in this technique, it can be called the symmetrical channels angular pressing (SCAP) method. This method resembles the more common ECAP process for samples with rectangular cross sections, with the difference that, in this method, the entrance and exit channels at the intersecting corner of the mold also have a twist about their longitudinal axis (as in the TE technique). In this study, to show the characteristics of the SCAP method and to compare it with the ECAP technique, the former method has been simulated by the ABAQUS/Explicit software. Also, to validate the obtained results, the SCAP and ECAP methods were practically applied on samples made of pure commercial aluminum (AA1050). To get the strain distribution along the longitudinal and transverse directions of the samples, Vickers hardness was measured on these samples. The results obtained from these hardness measurements indicate that after one pass, the SCAP method can achieve a higher amount of hardness, compared with the ECAP technique. Moreover, the strain distributions obtained from the simulation and from the samples demonstrate that the SCAP method produces a more homogeneous distribution of strain in the workpieces.

  17. 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…

  18. 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…

  19. Three-dimensional modeling of plastic deformation flow during ECAP

    SciTech Connect

    Budilov, I. N.; Alexandrov, I. V.; Beyerlein, Irene J.; Lukaschuk, Y. V.; Zhernakov, V. S.

    2004-01-01

    Plastic flow during equal-channel angular pressing (ECAP) of a copper billet is analyzed in this paper using three-dimensional finite element. The influence of the outer die radius and friction coefficient on the homogeneity in the accumulated plastic strain distribution is investigated. An increase in either outer radius or friction conditions was found to decrease the size of the steady-state region and increase heterogeneity in the final strain distribution from top to bottom and from side to side. Recent investigations have clearly demonstrated the great potential of the severe plastic deformation (SPD) methods, particularly by means of equal-channel angular pressing (ECAP), for ultra-fine grain refinement in various metals and alloys. One of the biggest challenges faced is the fabrication of larger and larger bulk ECAP samples with a uniform desired microstructure, e.g. equiaxed ultra-fine grains, and hence outstanding mechanical properties characteristic of such SPD materials. The degree of homogeneity depends on a myriad of processing and material variables. Numerical methods, such as finite elements (FE), have been an important tool in simulating the ECAP process and exploring the large ECAP parameter space, such as the pressing route and number of passes, die channel intersection angle, outer radius of the die, friction coefficient, pressing rate, material deformation response, and backpressure, e.g. Studying the effects of several factors simultaneously, however, can potentially lead to ambiguous conclusions about the regularities in the plastic flow, regularities in the material fill status, or the final distributions of accumulated total plastic strain. Thus more systematic studies using FE coupled with theoretical considerations are needed. Also, most of the FE studies found in the literature are two-dimensional analyses, and therefore cannot make conclusions regarding the influence of the confined character of plastic deformation on plastic flow in

  20. Finite Element Analysis of ECAP, TCAP, RUE and CGP Processes

    NASA Astrophysics Data System (ADS)

    Patil, Deepak C.; Kallannavar, Vinayak; Bhovi, Prabhakar M.; Kori, S. A.; Venkateswarlu, K.

    2016-02-01

    A finite element method was applied to study the various severe plastic deformation processes like, Equal Channel Angular Pressing (ECAP), Tubular Channel Angular Pressing (TCAP), Repetitive Upsetting and Extrusion (RUE) and Constrained Groove Pressing (CGP), considering aluminum AA-390 alloy as specimen material for all these processes. FEA simulation was carried out using AFDEX simulation tool. Effect of the various ECAP process parameters like, die corner angle, channel angle, and the coefficient of friction were analyzed. The die corner angles were divided into 2 equal parts for increasing the effectiveness of ECAP process, thereby increasing the channel number from 2 to 3 and further, their influence on ECAP process was investigated. A 3D simulation of TCAP was carried out for die shapes like triangular and trapezoidal, and variation of the generated stress and strain was plotted. In CGP, four cycle operation was carried out; wherein each cycle is composed of corrugating the specimen and subsequent straightening to original dimension. During RUE process, a maximum effective stress of 683.1 MPa was induced in the specimen after processing it for four complete cycles of RUE process; whereas the maximum strain induced during the same condition was 3.715.

  1. Incremental ECAP of thick continuous plates - machine and initial trials

    NASA Astrophysics Data System (ADS)

    Rosochowski, A.; Olejnik, L.

    2014-08-01

    Incremental ECAP (I-ECAP) can be used for SPD of continuous bars, plates and sheets. This paper describes design, construction and preliminary trials of a prototype machine capable of processing thick continuous plates. To increase productivity, a two-turn I-ECAP is used, which is equivalent to route C in conventional one-turn ECAP. The machine has a reciprocating punch inclined at 45°, a clamp holding the plate in the die during deformation and a feeder incrementally feeding the plate when it is not deformed; all these devices are driven by hydraulic actuators controlled by a PLC. The machine is capable of deforming materials at room temperature as well as elevated temperatures. The die is heated with electric heaters. The machine has also an integrated cooling system and a lubrication system. The material used for the initial trials was Al 1050 plate (10×50×1000) conversion coated with calcium aluminate and lubricated with dry soap. The process was carried out at room temperature using 1.6 mm feeding stroke and a low cycle frequency of approximately 0.2 Hz. The UFG structure after the first pass of the process revealed by STEM confirms process feasibility.

  2. ECAP spread of excitation with virtual channels and physical electrodes.

    PubMed

    Hughes, Michelle L; Stille, Lisa J; Baudhuin, Jacquelyn L; Goehring, Jenny L

    2013-12-01

    The primary goal of this study was to evaluate physiological spatial excitation patterns for stimulation of adjacent physical electrodes and intermediate virtual channels. Two experiments were conducted that utilized electrically evoked compound action potential (ECAP) spread-of-excitation (SOE) functions obtained with the traditional forward-masking subtraction method. These two experiments examined spatial excitation patterns for virtual-channel maskers and probes, respectively. In Experiment 1, ECAP SOE patterns were obtained for maskers applied to physical electrodes and virtual channels to determine whether virtual-channel maskers yield SOE patterns similar to those predicted from physical electrodes. In Experiment 2, spatial separation of SOE functions was compared for two adjacent physical probe electrodes and the intermediate virtual channel to determine the extent to which ECAP SOE patterns for virtual-channel probes are spatially separate from those obtained with physical electrodes. Data were obtained for three electrode regions (basal, middle, apical) for 35 ears implanted with Cochlear (N = 16) or Advanced Bionics (N = 19) devices. Results from Experiment 1 showed no significant difference between predicted and measured ECAP amplitudes for Advanced Bionics subjects. Measured ECAP amplitudes for virtual-channel maskers were significantly larger than the predicted amplitudes for Cochlear subjects; however, the difference was <2 μV and thus is likely not clinically significant. Results from Experiment 2 showed that the probe set in the apical region demonstrated the least amount of spatial separation amongst SOE functions, which may be attributed to more uniform nerve survival patterns, closer electrode spacing, and/or the tapered geometry of the cochlea. As expected, adjacent physical probes demonstrated greater spatial separation than for comparisons between each physical probe and the intermediate virtual channel. Finally, the virtual-channel SOE

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Finite element analysis of die angle at constant offset length in two-turn ECAP

    NASA Astrophysics Data System (ADS)

    Kumar, Pintu; Sekhar Panda, Sudhansu

    2016-09-01

    Severe plastic deformation (SPD) is the process used to produce smaller grain in the range of 1-pm. These materials have been classified as equiaxed ultrafine grain (UFG) metals. These metals are characterised by high defect density and improved mechanical properties which make them suitable for advanced structural applications. From all available SPD techniques, two turn incremental equal channel angular pressing (ECAP), S-shape channel discussed in this paper to double the effective strain in single press. Analysis of ECAP technique by changing die geometry and process parameter helps to produce defect free UFG metals. ECAP channel continuously pressed a very long billet in which repetitions accumulate large plastic strain. Two turn ECAP is useful to increase the productivity. However, any changes in channel angle, corner angle as well as offset length are cause for variation in mechanical properties of metals. In order to check the die suitability of two-turn ECAP with variation of die angle a finite element analysis (FEA) simulation is carried out and the suitable tool geometry with process kinematics are established. ECAP channels at two different channel angles are used to study the flow behaviour of metal through 15mm offset length. The mode of material flow is the same as in the well-established classical L-shape ECAP process following route C pass, while continuous character and improved productivity suggest that new S-shape ECAP process might be suitable for grain refinement of metals as well as minimization of deformation load on an industrial scale.

  8. Investigation of Microstructure and Mechanical Properties of ECAP-Processed AM Series Magnesium Alloy

    NASA Astrophysics Data System (ADS)

    Gopi, K. R.; Nayaka, H. Shivananda; Sahu, Sandeep

    2016-09-01

    Magnesium alloy Mg-Al-Mn (AM70) was processed by equal channel angular pressing (ECAP) at 275 °C for up to 4 passes in order to produce ultrafine-grained microstructure and improve its mechanical properties. ECAP-processed samples were characterized for microstructural analysis using optical microscopy, scanning electron microscopy, and transmission electron microscopy. Microstructural analysis showed that, with an increase in the number of ECAP passes, grains refined and grain size reduced from an average of 45 to 1 µm. Electron backscatter diffraction analysis showed the transition from low angle grain boundaries to high angle grain boundaries in ECAP 4 pass sample as compared to as-cast sample. The strength and hardness values an showed increasing trend for the initial 2 passes of ECAP processing and then started decreasing with further increase in the number of ECAP passes, even though the grain size continued to decrease in all the successive ECAP passes. However, the strength and hardness values still remained quite high when compared to the initial condition. This behavior was found to be correlated with texture modification in the material as a result of ECAP processing.

  9. Investigation of Microstructure and Mechanical Properties of ECAP-Processed AM Series Magnesium Alloy

    NASA Astrophysics Data System (ADS)

    Gopi, K. R.; Nayaka, H. Shivananda; Sahu, Sandeep

    2016-07-01

    Magnesium alloy Mg-Al-Mn (AM70) was processed by equal channel angular pressing (ECAP) at 275 °C for up to 4 passes in order to produce ultrafine-grained microstructure and improve its mechanical properties. ECAP-processed samples were characterized for microstructural analysis using optical microscopy, scanning electron microscopy, and transmission electron microscopy. Microstructural analysis showed that, with an increase in the number of ECAP passes, grains refined and grain size reduced from an average of 45 to 1 µm. Electron backscatter diffraction analysis showed the transition from low angle grain boundaries to high angle grain boundaries in ECAP 4 pass sample as compared to as-cast sample. The strength and hardness values an showed increasing trend for the initial 2 passes of ECAP processing and then started decreasing with further increase in the number of ECAP passes, even though the grain size continued to decrease in all the successive ECAP passes. However, the strength and hardness values still remained quite high when compared to the initial condition. This behavior was found to be correlated with texture modification in the material as a result of ECAP processing.

  10. Structure and property evolutions of ECAPed 7075 Al alloy during annealing.

    SciTech Connect

    Zhao, Y.; Liao, Xiaozhou; Zhu, Y. T.; Valiev, R. Z.

    2004-01-01

    Structure and microhardness evolutions of equal-channel angular pressing (ECAP) processed and coarse-grained (CG) 7075 A1 alloys during differential scanning calorimeter (DSC) were investigated by x-ray diffraction (XRD), transmission electron microscopy (TEM) and microhardness measurements. After one-month aging at room temperature, the microhardness of the ECAP processed sample is about 50% larger than that of the CG sample. During DSC annealing, the microhardness of the ECAP processed sample decreased gradually, while a hardening peak appeared for the CG sample. XRD and TEM show that the hardening peak of the CG sample was mainly caused by the precipitation hardening of the Guinier-Preston (GP) zone. For the ECAP processed sample, upon annealing the microstrain (dislocation density) decreased and the crystallites grew, which decreased the hardness and overcompensated the GP zone precipitation hardening. DSC analysis indicates ECAP process only promoted the phase precipitation, but did not change the sequence of phase precipitation.

  11. 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)

  12. Elementary Environmental Learning Packet K-3, Third Revised Edition. [Primary CEL Blocks, Student Activity Cards].

    ERIC Educational Resources Information Center

    Brevard County School Board, Cocoa, FL.

    This environmental education program consists of two levels: primary and intermediate. The learning materials are activity based and incorporate process and subject area skills with knowledge and concern for the environment. The program is also interdisciplinary including activities and skills from art, language arts, mathematics, music, science,…

  13. Equal-channel-angular processing (ECAP) of materials: Experiment and theory

    NASA Astrophysics Data System (ADS)

    Stoica, Grigoreta Mihaela

    Equal Channel-Angular Processing (ECAP), as a severe plastic deformation of metals and composites, is analyzed both theoretically---to describe the ECAP macromechanics---and experimentally---to obtain ultrafine-grained materials with new thermo-mechanical properties---with a focus on hexagonal-closed-packed (HCP) structures such as Mg alloys. Due to their obvious similarity to ECAP, the slip-line - field theories developed for orthogonal cutting are applied to the ECAP deformation for predicting the shear-strain spatial heterogeneities. A theoretical model for predicting the plastic-deformation zone in an ECAP-ed billet with a free surface is provided, and is validated experimentally. A shear-strain-mapping procedure was developed by decomposing the large deformation process into fine steps, and, by analyzing the partially-deformed billets, the strain maps captured the spatio-temporal evolutions of the ECAP-induced plastic shear strains. This approach was later generalized for studying the local behavior of different material parameters, such as textures (texture mapping). The mechanical testing of the as-received and ECAP-deformed Mg-alloys (ZK60 and AZ31) was performed in monotonic and cyclic tests, for three loading orientations. The ECAP-ed samples demonstrate: (a) a good grain refinement from 50--70 mum down to 2.5--7 mum), (b) a superplastic ZK60 alloy, with an elongation to failure of 371% at 3500C and the strain rate of 10-2 s-1, and (c) a longer fatigue life for the AZ31 alloy, relative to the as-received material. The starting and ECAP-deformed materials were characterized by optical microscopy, X-ray diffraction using both soft and hard X-rays, and neutron diffraction. The grain sizes, the textures, the coherent-domain sizes, the elastic microstrains, and the dislocation densities were determined for the samples deformed by rolling, extrusion, and ECAP. The synchrotron radiation measurements allowed monitoring the lattice rotation induced by the ECAP

  14. 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…

  15. 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…

  16. 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…

  17. Impedance and electrically evoked compound action potential (ECAP) drop within 24 hours after cochlear implantation.

    PubMed

    Chen, Joshua Kuang-Chao; Chuang, Ann Yi-Chiun; Sprinzl, Georg Mathias; Tung, Tao-Hsin; Li, Lieber Po-Hung

    2013-01-01

    Previous animal study revealed that post-implantation electrical detection levels significantly declined within days. The impact of cochlear implant (CI) insertion on human auditory pathway in terms of impedance and electrically evoked compound action potential (ECAP) variation within hours after surgery remains unclear, since at this time frequency mapping can only commence weeks after implantation due to factors associated with wound conditions. The study presented our experiences with regards to initial switch-on within 24 hours, and thus the findings about the milieus inside cochlea within the first few hours after cochlear implantation in terms of impedance/ECAP fluctuations. The charts of fifty-four subjects with profound hearing impairment were studied. A minimal invasive approach was used for cochlear implantation, characterized by a small skin incision (≈ 2.5 cm) and soft techniques for cochleostomy. Impedance/ECAP was measured intro-operatively and within 24 hours post-operatively. Initial mapping within 24 hours post-operatively was performed in all patients without major complications. Impedance/ECAP became significantly lower measured within 24 hours post-operatively as compared with intra-operatively (p<0.001). There were no differences between pre-operative and post-operative threshold for air-conduction hearing. A significant drop of impedance/ECAP in one day after cochlear implantation was revealed for the first time in human beings. Mechanisms could be related to the restoration of neuronal sensitivity to the electrical stimulation, and/or the interaction between the matrix enveloping the electrodes and the electrical stimulation of the initial switch-on. Less wound pain/swelling and soft techniques both contributed to the success of immediate initial mapping, which implied a stable micro-environment inside the cochlea despite electrodes insertion. Our research invites further studies to correlate initial impedance/ECAP changes with long

  18. Impedance and Electrically Evoked Compound Action Potential (ECAP) Drop within 24 Hours after Cochlear Implantation

    PubMed Central

    Chen, Joshua Kuang-Chao; Chuang, Ann Yi-Chiun; Sprinzl, Georg Mathias; Tung, Tao-Hsin; Li, Lieber Po-Hung

    2013-01-01

    Previous animal study revealed that post-implantation electrical detection levels significantly declined within days. The impact of cochlear implant (CI) insertion on human auditory pathway in terms of impedance and electrically evoked compound action potential (ECAP) variation within hours after surgery remains unclear, since at this time frequency mapping can only commence weeks after implantation due to factors associated with wound conditions. The study presented our experiences with regards to initial switch-on within 24 hours, and thus the findings about the milieus inside cochlea within the first few hours after cochlear implantation in terms of impedance/ECAP fluctuations. The charts of fifty-four subjects with profound hearing impairment were studied. A minimal invasive approach was used for cochlear implantation, characterized by a small skin incision (≈2.5 cm) and soft techniques for cochleostomy. Impedance/ECAP was measured intro-operatively and within 24 hours post-operatively. Initial mapping within 24 hours post-operatively was performed in all patients without major complications. Impedance/ECAP became significantly lower measured within 24 hours post-operatively as compared with intra-operatively (p<0.001). There were no differences between pre-operative and post-operative threshold for air-conduction hearing. A significant drop of impedance/ECAP in one day after cochlear implantation was revealed for the first time in human beings. Mechanisms could be related to the restoration of neuronal sensitivity to the electrical stimulation, and/or the interaction between the matrix enveloping the electrodes and the electrical stimulation of the initial switch-on. Less wound pain/swelling and soft techniques both contributed to the success of immediate initial mapping, which implied a stable micro-environment inside the cochlea despite electrodes insertion. Our research invites further studies to correlate initial impedance/ECAP changes with long

  19. Photoelectron circular dichroism in the multiphoton ionization by short laser pulses. I. Propagation of single-active-electron wave packets in chiral pseudo-potentials

    SciTech Connect

    Artemyev, Anton N.; Müller, Anne D.; Demekhin, Philipp V.; Hochstuhl, David

    2015-06-28

    A theoretical method to study the angle-resolved multiphoton ionization of polyatomic molecules is developed. It is based on the time-dependent formulation of the Single Center (TDSC) method and consists in the propagation of single-active-electron wave packets in the effective molecular potentials in the presence of intense laser pulses. For this purpose, the time-dependent Schrödinger equation for one electron, moving in a molecular field and interacting with an arbitrary laser pulse, is solved in spherical coordinates by an efficient numerical approach. As a test, the method is applied to the one- and two-photon ionizations of a model methane-like chiral system by circularly polarized short intense high-frequency laser pulses. Thereby, we analyze the photoelectron circular dichroism (PECD) in the momentum distribution. The considered model application illustrates the capability of the TDSC method to study multiphoton PECD in fixed-in-space and randomly oriented chiral molecules.

  20. 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.

  1. Comparative study of the influence of friction forces on cold forming processes in conventional ECAP die and ECAP die with low friction, by numerical simulation methods

    NASA Astrophysics Data System (ADS)

    Dragnea, D.; Lixandru, P.; Chereches, T.; Velicu, S.

    2016-08-01

    In the process of severe plastic deformation in the ECAP dies, the frictional forces between the blank and the walls of the dies play a determinant role on forming technologies. Due to the great length of the workpiece subjected to forming (in die), high frictional forces are developing, which can lead to blocking the forming process or even to the cracking of the dies. Two sets of numerical simulations were carried out for two coefficients of friction µ = 0.08 and µ = 0.10. There were analysed the following elements comparatively: the structure of the deformed mesh of the finished piece; the effective plastic strain fields; the Von Misses effective stress fields; the actuation forces on the die punch. The results of the numerical simulations showed: uniform structure of slipped layers in central areas of the finished parts, obtained by the two processes; the effective plastic strain field is uniformly at the process with low friction Von Misses effective stresses were significantly lower at the numerical simulation for the process with low friction; the application forces occurring in the processes carried out in the ECAP die with low friction are significantly lower than those obtained in conventional ECAP die.

  2. Spall properties of Al 5083 plate fabricated using equi-channel angular pressing (ECAP) and rolling

    NASA Astrophysics Data System (ADS)

    Whelchel, R. L.; Thadhani, N. N.; Sanders, T. H.; Kecskes, L. J.; Williams, C. L.

    2014-05-01

    The spall strength and Hugoniot Elastic Limit (HEL) of aluminum alloy 5083 (Al 5083) are compared for plates fabricated using equi-channel angular pressing (ECAP) and rolling. Al 5083 is a light-weight and strain-hardenable aluminum alloy used for armor plating in military transport vehicles, thus requiring the highest achievable spall strength and HEL. Materials that were processed by ECAP displayed a highly refined grain structure with little texture and a large degree of plastic deformation, whereas subsequent rolling resulted in a textured microstructure with both grains and inclusions aligning along the rolling direction. The spall behavior of Al 5083 was determined using plate-impact gas-gun experiments with rear free surface velocity measurements for a variety of processing conditions involving both ECAP and rolling. The spall strength and HEL increased from that of the as-received material after processing with ECAP. Subsequent rolling further increased the HEL but reduced the spall strength. Rolling also resulted in directional dependence of the spall strength, with the lowest spall strength occurring for impact through the plate thickness and highest spall strength in the rolling direction. The trends in the spall behavior correlate with the size and preferential alignment of manganese dispersoids and iron and silicon rich inclusions that are evolved during processing.

  3. 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…

  4. 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…

  5. 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…

  6. 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…

  7. 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…

  8. Elementary Environmental Learning Packet Grades 4-6, Third Revised Edition. [Intermediate CEL Blocks, Student Activity Cards].

    ERIC Educational Resources Information Center

    Brevard County School Board, Cocoa, FL.

    This environmental education program consists of two levels: primary and intermediate. The learning materials are activity based and incorporate process and subject area skills with knowledge and concern for the environment. The program is also interdisciplinary including activities and skills from several areas. The materials in this set for…

  9. 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

    , and the local ADI number. The destination ADI is used to route the packet to its ultimate destination. At each hop, the sending interface uses the destination address to determine the next node for the data. The sending node is the node address of the interface that is broadcasting the packet. This field is used to determine the health of the subsystem that is sending the packet. In the case of a packet that traverses several intermediate nodes, it may be the node address of the intermediate node. The target node is the node address of the next hop for the packet. It may be an intermediate node, or the final destination for the packet. The sequence number is used to identify duplicate packets. Because each interface has multiple transceivers, the same packet will appear at both receivers. The sequence number allows the interface to correlate the reception and forward a single, unique packet for additional processing. The subnet field allows data traffic to be partitioned into segregated local networks to support large networks while keeping each subnet at a manageable size. This also keeps the routing table small enough so routing can be done by a simple table lookup in an FPGA device. The subsystem class identifies members of a set of redundant subsystems, and, in a hot standby configuration, all members of the subsystem class will receive the data packets. Only the active subsystem will generate data traffic. Specific units in a class of redundant units can be identified and, if the hot standby configuration is not used, packets will be directed to a specific subsystem unit.

  10. 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.

  11. 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.

  12. 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)

  13. 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.

  14. Influence of grain boundaries on the deformation resistance: insights from an investigation of deformation kinetics and microstructure of copper after predeformation by ECAP

    NASA Astrophysics Data System (ADS)

    Bach, J.; Liebig, J. P.; Höppel, H. W.; Blum, W.

    2013-12-01

    The grain structure of coarse-grained Cu of different degrees of purity was modified by plastic deformation by ?, 4 and 8 passes of equal channel angular pressing (ECAP) at an ambient temperature with and without back pressure. The effect of this modification on deformation resistance was tested in rate change tests in compression at elevated temperatures up to 473. Electron microscopy and compressive strength evolution with strain confirmed that static recrystallization leads to grain coarsening during heating to test temperatures of 423 for ? and 473 for ? and that discontinuous grain coarsening by dynamic recry- stallization sets in already at ?. The influence of the grain structure on the deformation resistance is discussed in terms of a control loop considering generation and loss of free dislocations. The magnitude and rate dependence of the maximal deformation resistance of unrecrystallized ECAPed Cu were explained in terms of dynamic recovery at low- and high-angle boundaries as proposed previously. The interpretation sheds doubt on the common interpretation of rate change experiments in terms of thermally activated glide.

  15. 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.

  16. Equal Channel Angular Pressing (ECAP) and Its Application to Grain Refinement of Al-Zn-Mg-Cu Alloy

    SciTech Connect

    Tekeli, Sueleyman; Gueral, Ahmet

    2011-12-10

    Microstructure of a metal can be considerably changed by severe plastic deformation techniques such as high pressure torsion, extrusion and equal-channel angular pressing (ECAP). Among these methods, ECAP is particularly attractive because it has a potential for introducing significant grain refinement and homogeneous microstructure into bulk materials. Typically, it reduces the grain size to the submicrometer level or even nanometer range and thus produces materials that are capable of exhibiting unusual mechanical properties. In the present study, a test unites for equal channel angular pressing was constructed and this system was used for Al-Zn-Mg-Cu alloy. After the optimization tests, it was seen that the most effective lubricant for the dies was MoS{sub 2}, the pressing pressure was around 25-35 ton and the pressing speed was 2 mm/s. By using these parameters, the Al-Zn-Mg-Cu alloy was successfully ECAPed up to 14 passes at 200 deg. C using route C. After ECAP tests, the specimens were characterized by transmission electron microscope (TEM), hardness and macrostructural investigations. It was seen that the plastic deformation in the ECAPed specimens occurred from edge to the centre like whirlpool. In addition, the deformation intensity increased with increasing pass number. The grain size of the specimens effectively also decreased with increasing pass number. That is, while the grain size of unECAPed specimen was 10 {mu}m, this value decreased to 300 nm after 14 passes. At the beginning, while there was a banding tendency in the grains toward deformation direction, homogeneous and equiaxed grains were formed with increasing pass number. This grain refinement was as a result of an interaction between shear strain and thermal recovery during ECAP processing. Hardness measurements showed that the hardness values increased up to 4 passes, decreased effectively at 6th pass, again increased at 8th pass and after this pass, the hardness again decreased due to

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. Optimizing the equal channel angular pressing process (ECAP) operation parameters to produce bulk nanostructure materials

    SciTech Connect

    Abushgair, K.

    2015-03-30

    In this work we were interested in doing simulation using finite elements analysis (FEA) to study the equal channel angular pressing process (ECAP), which is currently one of the most popular methods of severe plastic deformation Processes (SPD). for fabricating Ultra-Fine Grained (UFG) materials, because it allows very high strains to be imposed leading to extreme work hardening and microstructural refinement. The main object of this study is to establish the influence of main parameters which effect ECAP process which are magnitude of the die angle and the friction coefficient. The angle studied between (90-135°) degree, and magnitude of the friction coefficient μ between (0.12-0.6), and number of pass. The samples were made from aluminum alloy at room temperature with (15X 15) mm cross section and 150 mm length. The simulation result shows that normal elastic strain, shears elastic strain, and max. shear elastic strain increased, when changing the angle from 90° to 100°. and decrease between the angle 110° to 135°. Also the total deformation increased when we change die angle from 90° to 135°. By studding the friction effect on the die and sample we noted that increasing the friction coefficient from 0.12 to 0.6, normal elastic strain, and shear elastic strain increased and increasing the friction coefficient from 0.1 to 0.6 decrease the normal and shear stress.

  3. Microstructure and mechanical behavior of UFG copper processed by ECAP following different processing regimes

    NASA Astrophysics Data System (ADS)

    Purcek, G.; Saray, O.; Nagimov, M. I.; Nazarov, A. A.; Safarov, I. M.; Danilenko, V. N.; Valiakhmetov, O. R.; Mulyukov, R. R.

    2012-02-01

    Commercially pure (99.9%) copper was severe plastically deformed by equal-channel angular pressing (ECAP) following route-Bc in three different processing regimes in order to obtain ultrafine-grained (UFG) microstructures leading to improved mechanical properties. In regime-1, the billets were processed at room temperature up to eight passes. The billets were processed at 200°C up to eight passes in regime-2. Regime-3 is a hybrid regime by which the billets were deformed at 200°C up to four passes first, and these billets were then processed at room temperature for one, two and four passes. In all regimes, the ECAP processing results in a refinement of the conventionally grained (CG) initial microstructure of copper down to sub-micron level leading to a great improvement in the strength as compared to CG copper. Among the regimes applied, regime-3 was found to be the best regime for improvement in strength along with adequate ductility. The samples showed more than eight times increases in yield strength after processing in regime-3 for 4 + 4 passes, from 47 MPa for CG copper to about 408 MPa for the UFG sample. Such improvement in strength was accompanied by a 16.9% total elongation and 6% uniform elongation. The processing in regime-2 resulted in the best elongation to failure of about 22% after eight passes, but it gave the lowest strength values among others.

  4. Recording and analysis of electrically evoked compound action potentials (ECAPs) with MED-EL cochlear implants and different artifact reduction strategies in Matlab.

    PubMed

    Bahmer, Andreas; Peter, Otto; Baumann, Uwe

    2010-08-15

    Electrically evoked compound action potentials (ECAPs) are used in auditory research to evaluate the response of the auditory nerve to electrical stimulation. Animal preparations are typically used for the recording. With the introduction of a new generation of cochlear implants, however it is possible to record the response of the auditory nerve to electrical stimulation in humans as well, which is used in the clinic to test whether the implant works properly and whether the auditory nerve is responsive. Currently, ECAPs are used to estimate thresholds for speech processor programs. In addition, ECAPs recordings allow new research to be addressed, e.g., to evaluate enhanced electrical stimulation patterns. Research platforms are required to test user-defined stimuli and algorithms for the ECAPs analysis. Clinical fitting software that records ECAPs is not flexible enough for this purpose. To enable a larger group of scientists to pursue research in this field, we introduce a flexible setup that allows to change stimulation and recording parameters. ECAP recording and analysis software was developed in Matlab (The Mathworks, Inc.) for standard PC, using a National instruments (PCI-6533, National Instruments, Austin, TX) card and a Research Interface Box 2 (RIB2, Department of Ion Physics and Applied Physics at the University of Innsbruck, Innsbruck, Austria) for MED-EL cochlear implants. ECAP recordings of a human subject with three different artifact reduction methods (alternating, Miller modified masker-probe, triphasic pulses) are presented and compared.

  5. The Effect of Multi-pass Equal-Channel Angular Pressing (ECAP) for Consolidation of Aluminum-Nano Alumina Composite Powder on Wear Resistance

    NASA Astrophysics Data System (ADS)

    Derakhshandeh-Haghighi, Reza; Jenabali Jahromi, Seyed Ahmad

    2016-02-01

    The wear behavior of aluminum matrix composite powder with varying concentration of nano alumina particles, which was consolidated by equal-channel angular pressing (ECAP) at different passes, was determined by applying, 10 and 46 N loads, using a pin-on-disk machine. Optical and electronic microscopy, EDX analysis, and hardness measurement were performed in order to characterize the worn samples. The relative density of the samples after each pass of ECAP was determined using Archimedes principle. Within the studied range of loads, the wear loss decreased by increasing the number of ECAP passes.

  6. 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.

  7. 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.

  8. 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

  9. 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…

  10. 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…

  11. 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)

  12. 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.

  13. 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.

  14. Microstructure heterogeneity after the ECAP process and its influence on recrystallization in aluminium

    SciTech Connect

    Wronski, S.; Tarasiuk, J.; Bacroix, B.; Wierzbanowski, K.; Paul, H.

    2013-04-15

    The main purpose of the present work is to describe the qualitative and quantitative behaviours of aluminium during high strain plastic deformation and the effect of deformation on the subsequent recrystallization process. An Electron Backscatter Diffraction analysis of aluminium after the Equal channel angular pressing (ECAP) and recrystallization process is presented. In order to do this, several topological maps are measured for samples processed by 4 and 8 passes and recrystallized. The processing was conducted with route C. For all samples, distributions of grain size, misorientation, image quality factor (IQ) and texture were preceded and then analysed in some detail. - Highlights: ► Describe the microstructure fragmentation in aluminum. ► High strain plastic deformation and effect of deformation on recrystallization. ► The microstructure fragmentation and its influence on recrystallization. ► Image quality factor and misorientation characteristics are examined using EBSD.

  15. 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…

  16. 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.

  17. 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.…

  18. 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,…

  19. 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…

  20. 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…

  1. 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…

  2. 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...

  3. 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)

  4. [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."…

  5. 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,…

  6. [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."…

  7. 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…

  8. Packet personal radiation monitor

    DOEpatents

    Phelps, James E.

    1989-01-01

    A personal radiation monitor of the chirper type is provided for detecting ionizing radiation. A battery powered high voltage power supply is used to generate and apply a high voltage bias to a G-M tube radiation sensor. The high voltage is monitored by a low-loss sensing network which generates a feedback signal to control the high voltage power supply such that the high voltage bias is recharged to +500 VDC when the current pulses of the sensor, generated by the detection of ionizing radiation events, discharges the high voltage bias to +450 VDC. During the high voltage recharge period an audio transducer is activated to produce an audible "chirp". The rate of the "chirps" is controlled by the rate at which the high voltage bias is recharged, which is proportional to the radiation field intensity to which the sensor is exposed. The chirp rate sensitivity is set to be approximately 1.5 (chirps/min/MR/hr.). The G-M tube sensor is used in a current sensing mode so that the device does not paralyze in a high radiation field.

  9. Packet personal radiation monitor

    DOEpatents

    Phelps, J.E.

    1988-03-31

    A personal radiation monitor of the chirper type is provided for detecting ionizing radiation. A battery powered high voltage power supply is used to generate and apply a high voltage bias to a G-M tube radiation sensor. The high voltage is monitored by a low-loss sensing network which generates a feedback signal to control the high voltage power supply such that the high voltage bias is recharged to +500 VDC when the current pulses of the sensor, generated by the detection of ionizing radiatonevents, discharges the high voltage bias to +450 VDC. During the high voltage recharge period an audio transducer is activated to produce an audible ''chirp''. The rate of the ''chirps'' is controlled by the rate at which the high voltage bias is recharged, which is proportional to the radiation field intensity to which the sensor is exposed. The chirp rate sensitivity is set to be approximately 1.5 (chirps/min/MR/hr.). The G-M tube sensor is used in a current sensing mode so that the device does not paralyze in a high radiation field. 2 figs.

  10. 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…

  11. Effect of molybdenum addition to ZA22 grain refined by titanium in the cast and after pressing by ECAP

    NASA Astrophysics Data System (ADS)

    Zaid, Adnan I. O.; Al-Hunetti, N. S.; Eyal-Awwad, K. Y. S.

    2016-08-01

    Zinc aluminum alloys are versatile materials which are widely used in manufacturing many industrial and engineering parts due to their attractive properties. The ZA22 has the extra advantage of possessing super plastic behavior within the temperature range from 350 to 375°C. The equal channel angular pressing, ECAP is a relatively recent manufacturing process by which heavy plastic deformation can be produced in materials resulting in grain refinement of its microstructure. It is, therefore, anticipated that if the ECAP process is applied to the ZA22 alloy after being grain refined by certain grain refiners may produce super plastic behavior in this alloy at room temperature, by this eliminating the heating process and its costs, hence widening its applications rendering it to be cost effective. In this paper, the effect of molybdenum addition at a rate of 0.1 % wt. to ZA22 grain refined by Ti on its metallurgical and mechanical characteristics in the cast condition and after applying the ECAP process is investigated. It was found that addition of Mo to ZA22 either in the nonrefined or the refined by Ti resulted in refining its structure being more refined in the latter. The ECAP process resulted in further refinement of its structure of the ZA22-Ti, ZA22-Mo and the ZA22-Ti-Mo alloys. Regarding the mechanical behavior, it was found that addition of Mo to ZA22 resulted in pronounced reduction of its mechanical strength presented by the following values of the flow stress at 20% strain: from 451 MPa to 346 MPa, whereas pronounced increase in case of Ti addition i.e. by 22.22% and only increase of 1.1% when Mo is added in the presence of Ti. However the Vickers hardness HV was increased by 5% in case of Ti addition and 2.5% increase in case of Mo addition. Finally it was concluded that super plastic behavior was obtained at room temperature by the addition of Mo and the ECAP process.

  12. 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.

  13. Thermal stability of bimodal microstructure in magnesium alloy AZ91 processed by ECAP

    SciTech Connect

    Pantělejev, Libor

    2015-09-15

    The changes in microstructure of equal channel angular pressing (ECAP) processed magnesium alloy AZ91 during thermal exposure were studied in this paper. The microstructure stability was investigated by means of electron backscatter diffraction (EBSD), which allowed to measure the changes in grain size, mutual ratio of low-angle boundaries (LABs) to high-angle ones (HABs) and local lattice distortion evaluated by the kernel average misorientation (KAM) parameter. It was found experimentally that the threshold temperature at which significant grain coarsening takes place is 350 °C. No modification to mean grain diameter occurs below this temperature, nonetheless, some changes in LAB and HAB fraction, as well as in local lattice distortion, can be observed. - Highlights: • Thermal stability of bimodal UFG AZ91 alloy was assessed by means of EBSD. • Threshold temperature for pronounced grain coarsening was found at 350 °C. • Below 350 °C increase in LAB fraction and local lattice distortion takes place. • Local lattice distortion (LLD) can be well described using KAM approach. • LLD is influenced by coarsening and precipitation of Mg{sub 17}Al{sub 12} particles.

  14. 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).

  15. 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

  16. Microstructure stability of ultra-fine grained magnesium alloy AZ31 processed by extrusion and equal-channel angular pressing (EX–ECAP)

    SciTech Connect

    Stráská, Jitka; Janeček, Miloš; Čížek, Jakub; Stráský, Josef; Hadzima, Branislav

    2014-08-15

    Thermal stability of the ultra-fine grained (UFG) microstructure of magnesium AZ31 alloy was investigated. UFG microstructure was achieved by a combined two-step severe plastic deformation process: the extrusion (EX) and subsequent equal-channel angular pressing (ECAP). This combined process leads to refined microstructure and enhanced microhardness. Specimens with UFG microstructure were annealed isochronally at temperatures 150–500 °C for 1 h. The evolution of microstructure, mechanical properties and dislocation density was studied by electron backscatter diffraction (EBSD), microhardness measurements and positron annihilation spectroscopy (PAS). The coarsening of the fine-grained structure at higher temperatures was accompanied by a gradual decrease of the microhardness and decrease of dislocation density. Mechanism of grain growth was studied by general equation for grain growth and Arrhenius equation. Activation energies for grain growth were calculated to be 115, 33 and 164 kJ/mol in temperature ranges of 170–210 °C, 210–400 °C and 400–500 °C (443–483 K, 483–673 K and 673–773 K), respectively. - Highlights: • Microhardness of UFG AZ31 alloy decreases with increasing annealing temperature. • This fact has two reasons: dislocation annihilations and/or grain growth. • The activation energies for grain growth were calculated for all temperature ranges.

  17. Effect of ECAP-based choice of stimulation rate on speech-perception performance

    PubMed Central

    Bournique, Jennifer L.; Hughes, Michelle L.; Baudhuin, Jacquelyn L.; Goehring, Jenny L.

    2012-01-01

    Objectives The objective determination of an optimal stimulation rate for CI users could save time and take the uncertainty out of choosing a rate based on patient preference. Electrically evoked compound action potential (ECAP) temporal response patterns vary across stimulation rates and cochlear regions, and could be useful in objectively predicting an optimal rate. Given that only one rate of stimulation can be used for current CI devices, we propose two potential ways to investigate whether a rate that produces stochastic ECAP responses (termed stochastic rate) can be used to predict an optimal stimulation rate. The first approach follows that of Hochmair et al. (2003), which compared performance across three cochlear regions using limited electrode sets. This approach, which has inherent limitations, may provide insight into the effects of region-specific stochastic rates on performance. The second, more direct approach is to compare speech perception for full-array maps that each employs a stochastic rate from a different region of the cochlea. Using both of these methods in a set of two acute experiments, the goal of the present study was to assess the effects of stochastic rate on speech perception. Design Speech-perception stimuli included the Hearing in Noise Test (HINT sentences), Consonant-Nucleus-Consonant (CNC) phonemes, and Iowa Medial Consonants. For Experiment 1, 22 ears in 20 CI recipients were tested in three map conditions (basal-only, middle-only, and apical-only electrode sets) using the subject’s daily-use stimulation rate to first explore the level of performance possible with region-specific maps. A one-way repeated-measures analysis of variance (RM ANOVA) was used to examine the effect of electrode region on performance. A subset of nine subjects was tested with three additional maps (basal-only, middle-only, and apical-only electrode sets) using the region-specific stochastic rate, as measured in a previous study. A two-way RM ANOVA was

  18. User's Guide for ECAP2D: an Euler Unsteady Aerodynamic and Aeroelastic Analysis Program for Two Dimensional Oscillating Cascades, Version 1.0

    NASA Technical Reports Server (NTRS)

    Reddy, T. S. R.

    1995-01-01

    This guide describes the input data required for using ECAP2D (Euler Cascade Aeroelastic Program-Two Dimensional). ECAP2D can be used for steady or unsteady aerodynamic and aeroelastic analysis of two dimensional cascades. Euler equations are used to obtain aerodynamic forces. The structural dynamic equations are written for a rigid typical section undergoing pitching (torsion) and plunging (bending) motion. The solution methods include harmonic oscillation method, influence coefficient method, pulse response method, and time integration method. For harmonic oscillation method, example inputs and outputs are provided for pitching motion and plunging motion. For the rest of the methods, input and output for pitching motion only are given.

  19. 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.

  20. 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.

  1. 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).

  2. 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.

  3. 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.

  4. 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)

  5. 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.

  6. 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.

  7. 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.

  8. Fast WEP-Key Recovery Attack Using Only Encrypted IP Packets

    NASA Astrophysics Data System (ADS)

    Teramura, Ryoichi; Asakura, Yasuo; Ohigashi, Toshihiro; Kuwakado, Hidenori; Morii, Masakatu

    Conventional efficient key recovery attacks against Wired Equivalent Privacy (WEP) require specific initialization vectors or specific packets. Since it takes much time to collect the packets sufficiently, any active attack should be performed. An Intrusion Detection System (IDS), however, will be able to prevent the attack. Since the attack logs are stored at the servers, it is possible to prevent such an attack. This paper proposes an algorithm for recovering a 104-bit WEP key from any IP packets in a realistic environment. This attack needs about 36, 500 packets with a success probability 0.5, and the complexity of our attack is equivalent to about 220 computations of the RC4 key setups. Since our attack is passive, it is difficult for both WEP users and administrators to detect our attack.

  9. 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.

  10. Structures and mechanical properties of ECAP processed 7075 AI alloy upon natural aging and T651 treatment.

    SciTech Connect

    Zhao, Y.; Liao, Xiaozhou; Valiev, R. Z.; Zhu, Y. T.

    2004-01-01

    Equal-channel angular pressing (ECAP) processed ultrafine grained (UFG) and coarse grained (CG) 7075 Al alloys were treated by natural aging and T651 temper (annealed at 120 C for 48 h in Ar atmosphere), respectively. Mechanical tests showed that for the UFG sample, the natural aging resulted in the highest strength (the ultimate tensile strength is 720 MPa). In contrast, for the CG sample, the T651 treatment resulted in the higher strength (the ultimate strength is 590 MPa) than the natural aging (530 MPa). Microstructural analyses indicated that the enhanced strength of the T651 treated CG sample was mainly caused by high densities of G-P zones and metastable {eta}{prime} precipitate. The enhanced strength of the naturally aged UFG sample was mainly caused by the high densities of G-P zones and dislocations. Upon T65 1 treatment, the dislocation density of the UFG sample deceased significantly, overcompensating the precipitation strengthening.

  11. 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.

  12. 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.

  13. In vitro and in vivo studies of ultrafine-grain Ti as dental implant material processed by ECAP.

    PubMed

    An, Baili; Li, Zhirui; Diao, Xiaoou; Xin, Haitao; Zhang, Qiang; Jia, Xiaorui; Wu, Yulu; Li, Kai; Guo, Yazhou

    2016-10-01

    The aim of this study was to investigate the surface characterization of ultrafine-grain pure titanium (UFG-Ti) after sandblasting and acid-etching (SLA) and to evaluate its biocompatibility as dental implant material in vitro and in vivo. UFG-Ti was produced by equal channel angular pressing (ECAP) using commercially pure titanium (CP-Ti). Microstructure and yield strength were investigated. The morphology, wettability and roughness of the specimens were analyzed after they were modified by SLA. MC3T3-E1 osteoblasts were seeded onto the specimens to evaluate its biocompatibility in vitro. For the in vivo study, UFG-Ti implants after SLA were embedded into the femurs of New Zealand rabbits. Osseointegration was investigated though micro-CT analysis, histological assessment and pull-out test. The control group was CP-Ti. UFG-Ti with enhanced mechanical properties was produced by four passes of ECAP in BC route at room temperature. After SLA modification, the hierarchical porous structure on its surface exhibited excellent wettability. The adhesion, proliferation and viability of cells cultured on the UFG-Ti were superior to that of CP-Ti. In the in vivo study, favorable osseointegration occurred between the implant and bone in CP and UFG-Ti groups. The combination intensity of UF- Ti with bone was higher according to the pull-out test. This study supports the claim that UFG-Ti has grain refinement with outstanding mechanical properties and, with its excellent biocompatibility, has potential for use as dental implant material.

  14. In vitro and in vivo studies of ultrafine-grain Ti as dental implant material processed by ECAP.

    PubMed

    An, Baili; Li, Zhirui; Diao, Xiaoou; Xin, Haitao; Zhang, Qiang; Jia, Xiaorui; Wu, Yulu; Li, Kai; Guo, Yazhou

    2016-10-01

    The aim of this study was to investigate the surface characterization of ultrafine-grain pure titanium (UFG-Ti) after sandblasting and acid-etching (SLA) and to evaluate its biocompatibility as dental implant material in vitro and in vivo. UFG-Ti was produced by equal channel angular pressing (ECAP) using commercially pure titanium (CP-Ti). Microstructure and yield strength were investigated. The morphology, wettability and roughness of the specimens were analyzed after they were modified by SLA. MC3T3-E1 osteoblasts were seeded onto the specimens to evaluate its biocompatibility in vitro. For the in vivo study, UFG-Ti implants after SLA were embedded into the femurs of New Zealand rabbits. Osseointegration was investigated though micro-CT analysis, histological assessment and pull-out test. The control group was CP-Ti. UFG-Ti with enhanced mechanical properties was produced by four passes of ECAP in BC route at room temperature. After SLA modification, the hierarchical porous structure on its surface exhibited excellent wettability. The adhesion, proliferation and viability of cells cultured on the UFG-Ti were superior to that of CP-Ti. In the in vivo study, favorable osseointegration occurred between the implant and bone in CP and UFG-Ti groups. The combination intensity of UF- Ti with bone was higher according to the pull-out test. This study supports the claim that UFG-Ti has grain refinement with outstanding mechanical properties and, with its excellent biocompatibility, has potential for use as dental implant material. PMID:27287096

  15. 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

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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'.

  1. 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…

  2. 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…

  3. 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…

  4. 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…

  5. 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.

  6. [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…

  7. 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.

  8. 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.

  9. ZooScope. Teacher's Packet.

    ERIC Educational Resources Information Center

    Henrie, Charis

    This curriculum provides background information and activities for teaching inquiry-based science in the classroom and at the Oregon Zoo. The ZooScope program was created to provide students with hands-on and minds-on activities that are crucial to taking theoretical learning into the real world. The hope is that as students begin asking about the…

  10. Drug Courts. Technical Assistance Packet.

    ERIC Educational Resources Information Center

    Join Together, Boston, MA.

    Drug courts are designed to stop the abuse of alcohol and other drugs and the related criminal activity by offering individuals, whose criminal activity stems from substance abuse, the choice to participate in treatment. In exchange for successful completion of a treatment program, the court has the option of dismissing the original charge,…

  11. A Study of the Earth: "Everything Comes from Our Natural Resources." Teacher's Helper Packet.

    ERIC Educational Resources Information Center

    Mineral Information Inst., Denver, CO.

    This instructional information packet had been prepared to help teachers plan lessons and activities related to natural resources. It contains posters, activity sheets, teacher guides, student pages, background and study sheets, video and reading lists, free video offers, and sources for more information. (JRH)

  12. SCDC Spanish Curricula Units. Fine Arts, Unit 4, Grade 2, Supplements & Ditto Packet.

    ERIC Educational Resources Information Center

    Spanish Curricula Development Center, Miami Beach, FL.

    The supplement and ditto packet to the unit four fine arts strand for second graders contains visual materials to aid the teacher in carrying out the instructional and assessment activities of this strand. Seatwork for individual students is featured along with materials intended for class participation activities. Illustrations, provided to help…

  13. SCDC Spanish Curricula Units. Language Arts, Unit 6, Grade 2, Supplement & Ditto Packet.

    ERIC Educational Resources Information Center

    Spanish Curricula Development Center, Miami Beach, FL.

    The supplement and ditto packet for the unit six language arts strand for second graders features visual aids to help carry out the activities described in the teacher's guide. Visuals based on the stories are used to help stimulate oral language and conceptual development along with class participation activities and written work. Other materials…

  14. SCDC Spanish Curricula Units. Fine Arts Strand, Unit 9, Grade 3, Supplement & Ditto Packet.

    ERIC Educational Resources Information Center

    Spanish Curricula Development Center, Miami Beach, FL.

    The supplement and ditto packet to the fine arts strand of unit nine for third graders contains illustrations, ditto masters, and four songbooks to help the teacher carry out the fine arts activities of this unit. Materials for both group activities and seatwork are included. Kit 33 uses the songbook "Canciones de Aqui y de Alla" and studies the…

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. The Prevalence of Asthma and Declared Asthma in Poland on the Basis of ECAP Survey Using Correspondence Analysis

    PubMed Central

    Zalewska, M.; Furmańczyk, K.; Jaworski, S.; Niemiro, W.; Samoliński, B.

    2013-01-01

    Results of epidemiological and public health surveys are often presented in the form of cross-classification tables. It is sometimes difficult to analyze data described in this way and to understand relations between variables. Graphical methods such as correspondence analysis are more convenient and useful. Our paper describes an application of correspondence analysis to epidemiological research. We apply the basic concepts of correspondence analysis like profiles, chi-square distance to medical data concerning prevalence of asthma. We aim at describing the relationship between asthma, region, and age. The data presented in this paper come from Epidemiology of Allergy in Poland (ECAP) survey in years 2006–2008. Correspondence analysis shows that there is a fundamental difference in the structure of age groups for people with symptoms compared to those who have declared asthma (regardless of the level of symptoms of asthma and the level of declaration). The variable which best differentiates declared asthma in all regions is “wheezing and whistling.” Correspondence analysis also shows significant differences between locations. Our analyses are performed in the R package “ca”. PMID:23401722

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. This Is Challenger Center...Changing the Way Teachers Teach and Students Learn. [Information Packet].

    ERIC Educational Resources Information Center

    Challenger Center for Space Science Education, Alexandria, VA.

    The Challenger Center for Space Science Education is a not-for-profit educational organization founded in 1986 following the Challenger 51-L space shuttle tragedy. This packet contains a variety of separate sheets and brochures providing information about the activities of the Challenger Center. Challenger Learning Centers provide hands-on,…

  8. Learning Packet in Social Studies (8th Grade) for ESOL Students.

    ERIC Educational Resources Information Center

    Clemons, Jacquelyn; And Others

    The learning packet is intended to provide the eighth grade social studies teacher with supplemental material for teaching beginning and intermediate students of English as a second language. It contains a variety of activities to assist in developing the student's vocabulary skills, reading comprehension, writing skills, and a working knowledge…

  9. SCDC Spanish Curricula Units. Science/Math Strand, Unit 3, Grade One, Supplement & Ditto Packet.

    ERIC Educational Resources Information Center

    Spanish Curricula Development Center, Miami Beach, FL.

    Instructional aids and ditto masters for unit three of a science/math curriculum in Spanish for first graders are included in this supplement and ditto packet. Encompassing kits 9-12, these materials are designed for use with learning activities referred to in the teacher's guide corresponding to this unit. Illustrations and materials for both…

  10. SCDC Spanish Curricula Units. Science/Math Strand, Unit 9, Grade 3, Supplement & Ditto Packet.

    ERIC Educational Resources Information Center

    Spanish Curricula Development Center, Miami Beach, FL.

    Designed to help the teacher in presenting the material of unit nine's science-math strand for third graders, this supplement and ditto packet contains both group visual aids and seatwork activities for individual students. Notations in the teacher's guide indicate when the supplementary materials should be used. Concepts explored in the four kits…

  11. Plant Galls and Ecological Concepts: A Multidisciplinary Outdoor Education Teaching Resource Packet.

    ERIC Educational Resources Information Center

    Matthews, Bruce; And Others

    Designed for adaptation in primary through high school classes, the lessons in this resource packet use the development of plant galls (plant growths caused by irritation of the plant tissue) as a focus for outdoor education studies and activities. Emphasis is on science and ecology, though other disciplines are represented. Illustrations and…

  12. Transitions: Turning Risks into Opportunities for Student Support. An Introductory Packet.

    ERIC Educational Resources Information Center

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

    This Introductory Packet provides readings and related activities on support for transitions to address barriers to student learning covering both research and best practices. It explores why transitions are dangerous opportunities that can disrupt or promote development. Key transitions and related intervention strategies are presented for…

  13. When I Was Hungry. A Hunger Course for High School Students. Teacher's Manual [and] Action Packet.

    ERIC Educational Resources Information Center

    Bread for the World Educational Fund, Washington, DC.

    Designed to accompany a student activity packet on issues related to world hunger, this teacher's manual provides 12 units of study at the high school level. Materials are presented from a Christian perspective. The following topics are covered in separate chapters: introduction (justice and the right to food), the dimensions and scope of the…

  14. Schools Are for All Kids. Part II: School Site Implementation. Trainer's Packet.

    ERIC Educational Resources Information Center

    Roger, Blair; And Others

    This trainer's packet, designed to be used in conjunction with the participant's manual, was prepared for a 2-day workshop to restructure schools to embrace all children, including those with disabilities. The trainer's materials include: program objectives; masters for overhead transparencies; and descriptions of learning activities, including…

  15. Intermediate SCDC Spanish Curricula Units. Spanish SL, Unit 1, Kits 1-4, Supplement & Ditto Packet.

    ERIC Educational Resources Information Center

    Spanish Curricula Development Center, Miami Beach, FL.

    Designed for use with the teacher's guide to the Spanish as a Second Language unit, this supplement and ditto packet includes visual aids and worksheets to help the teacher carry out the instructional and assessment activities. The illustrations are designed to help stimulate oral language and conceptual development. These visual materials…

  16. 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.

  17. 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.

  18. 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'.

  19. 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.

  20. 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…

  1. 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.

  2. 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.

  3. 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…

  4. 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…

  5. 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)

  6. 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…

  7. 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).

  8. 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.

  9. Filaggrin Gene Defects Are Independent Risk Factors for Atopic Asthma in a Polish Population: A Study in ECAP Cohort

    PubMed Central

    Ponińska, Joanna; Samoliński, Bolesław; Tomaszewska, Aneta; Raciborski, Filip; Samel-Kowalik, Piotr; Walkiewicz, Artur; Lipiec, Agnieszka; Piekarska, Barbara; Komorowski, Jarosław; Krzych-Fałta, Edyta; Namysłowski, Andrzej; Borowicz, Jacek; Kostrzewa, Grażyna; Majewski, Sławomir; Płoski, Rafał

    2011-01-01

    Background FLG null variants of which 2282del4 and R501X are the most frequent in Caucasians are established risk factors for atopic dermatitis (AD) with an effect probably mediated through impairment of epidermal barrier. Among subjects with AD FLG defects are also consistently associated with asthma and allergic rhinitis (AR) but it is less clear to what extent these associations are also present independently from skin disease. The aim of the present study was to evaluate the role of 2282del4 and R501X in predisposing to these allergic phenotypes in a Polish population. Methodology 2282del4 and R501X were typed among 3,802 participants of the Epidemiology of Allergic Diseases in Poland (ECAP) survey, a cross-sectional population-based study using ECRHS II and ISAAC questionnaires, and ambulatory examination. Principal Findings The FLG null variants were associated with AD (OR = 2.01, CI: 1.20–3.36, P = 0.007), allergic rhinitis (in particular persistent form, OR = 1.69, CI:1.12–2.54, P = 0.011), and asthma (in particular atopic asthma, OR = 2.22, CI:1.24–3.96, P = 0.006). Association with atopic asthma (but not persistent allergic rhinitis) was also present in the absence of AD, (OR = 2.02, CI: 1.07–3.81, P = 0.027) as well as in the absence of AD and history of broadly defined inflammatory skin disease (OR = 2.30, CI: 1.07–4.93, P = 0.03). Association to atopic asthma would have not been found if diagnosis was made by questionnaire only (OR = 1.15, CI: 0.58–2.32, P = 0.8). We did not observe an association between FLG variants and allergic sensitizations (P = 0.8) or total IgE. (P = 0.6). Conclusions/Significance In a Polish population FLG 2282del4 and R501X carriage increases risk for development of AD and atopic asthma (also in the absence of AD or history thereof). This suggests that interventions aimed at restoring epidermal barrier may have a general role in asthma prophylaxis

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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).

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. An On-Demand Emergency Packet Transmission Scheme for Wireless Body Area Networks

    PubMed Central

    Al Ameen, Moshaddique; Hong, Choong Seon

    2015-01-01

    The rapid developments of sensor devices that can actively monitor human activities have given rise to a new field called wireless body area network (BAN). A BAN can manage devices in, on and around the human body. Major requirements of such a network are energy efficiency, long lifetime, low delay, security, etc. Traffic in a BAN can be scheduled (normal) or event-driven (emergency). Traditional media access control (MAC) protocols use duty cycling to improve performance. A sleep-wake up cycle is employed to save energy. However, this mechanism lacks features to handle emergency traffic in a prompt and immediate manner. To deliver an emergency packet, a node has to wait until the receiver is awake. It also suffers from overheads, such as idle listening, overhearing and control packet handshakes. An external radio-triggered wake up mechanism is proposed to handle prompt communication. It can reduce the overheads and improve the performance through an on-demand scheme. In this work, we present a simple-to-implement on-demand packet transmission scheme by taking into considerations the requirements of a BAN. The major concern is handling the event-based emergency traffic. The performance analysis of the proposed scheme is presented. The results showed significant improvements in the overall performance of a BAN compared to state-of-the-art protocols in terms of energy consumption, delay and lifetime. PMID:26690161

  14. Intermediate SCDC Spanish Curricula Units. Science/Health, Unit 1, Kits 1-4, Supplement & Ditto Packet.

    ERIC Educational Resources Information Center

    Spanish Curricula Development Center, Miami Beach, FL.

    Visual aids and ditto masters for the first unit of a science/health curriculum for the intermediate level are included in this supplement and ditto packet. The visual aids are designed to help stimulate oral language and conceptual development through group activities and individual seatwork. Intended to help the teacher successfully carry out…

  15. Highly survivable communications: Complementary media packet switched networks

    NASA Astrophysics Data System (ADS)

    Yavuz, D.; Eken, F.; Karavassilis, N.

    1994-07-01

    The requirement for highly survivable communications (HSC) for essential command functions in military operations does not need any justification. The ability to communicate under extreme jamming levels and adverse propagation conditions, including high altitude nuclear events, is a very important requirement. There are also many natural disaster related requirements that also need such highly survivable communications. The prevalent and in a sense classical, approach to provide highly assured connectivity can be summarized as follows: Take a particular propagation medium and try to obtain the ultimate performance from it. There are many examples of this philosophy some successful, most not. Our approach, on the other hand, is to use complementary multi-media or mixed-media where communication links utilizing essentially commercial-off-the-shelf (COTS) equipment are integrated using packet radio (PR) techniques. There is also, in our view, an even more fundamental, recently discovered consideration why the expectation of continuous incremental refinement of a system using a given single media may be be achievable. This is derived from the theory of 'deterministic uncertainty' or more popularly known as 'theory of CHAOS', systems whose state space behavior has fractal characteristics. We will elaborate on this novel argument. Complementary multi-media approach has been the focus for all HSC communications activities at STC since 1982. The original STC studies and prototypes were in response to requirements of broadcasting (i.e., one-way transmission) information. A high frequency (HF)/meteorburst (MB) system was developed/prototyped/tested demonstrating the cost effectiveness of the approach. These results are reviewed. More recently, in 1992 STC has completed the development/test of an Open Systems Interconnection (OSI) HF packet radio protocol as no such open or non-proprietary protocol exists. This protocol has been fully tested, documented and made available to

  16. Congestion Control for a Fair Packet Delivery in WSN: From a Complex System Perspective

    PubMed Central

    2014-01-01

    In this work, we propose that packets travelling across a wireless sensor network (WSN) can be seen as the active agents that make up a complex system, just like a bird flock or a fish school, for instance. From this perspective, the tools and models that have been developed to study this kind of systems have been applied. This is in order to create a distributed congestion control based on a set of simple rules programmed at the nodes of the WSN. Our results show that it is possible to adapt the carried traffic to the network capacity, even under stressing conditions. Also, the network performance shows a smooth degradation when the traffic goes beyond a threshold which is settled by the proposed self-organized control. In contrast, without any control, the network collapses before this threshold. The use of the proposed solution provides an effective strategy to address some of the common problems found in WSN deployment by providing a fair packet delivery. In addition, the network congestion is mitigated using adaptive traffic mechanisms based on a satisfaction parameter assessed by each packet which has impact on the global satisfaction of the traffic carried by the WSN. PMID:25177722

  17. 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.

  18. Congestion control for a fair packet delivery in WSN: from a complex system perspective.

    PubMed

    Aguirre-Guerrero, Daniela; Marcelín-Jiménez, Ricardo; Rodriguez-Colina, Enrique; Pascoe-Chalke, Michael

    2014-01-01

    In this work, we propose that packets travelling across a wireless sensor network (WSN) can be seen as the active agents that make up a complex system, just like a bird flock or a fish school, for instance. From this perspective, the tools and models that have been developed to study this kind of systems have been applied. This is in order to create a distributed congestion control based on a set of simple rules programmed at the nodes of the WSN. Our results show that it is possible to adapt the carried traffic to the network capacity, even under stressing conditions. Also, the network performance shows a smooth degradation when the traffic goes beyond a threshold which is settled by the proposed self-organized control. In contrast, without any control, the network collapses before this threshold. The use of the proposed solution provides an effective strategy to address some of the common problems found in WSN deployment by providing a fair packet delivery. In addition, the network congestion is mitigated using adaptive traffic mechanisms based on a satisfaction parameter assessed by each packet which has impact on the global satisfaction of the traffic carried by the WSN. PMID:25177722

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Alfvénic wave packets collision in a kinetic plasma

    NASA Astrophysics Data System (ADS)

    Pezzi, Oreste; Parashar, Tulasi N.; Servidio, Sergio; Valentini, Francesco; Malara, Francesco; Matthaeus, William H.; Veltri, Pierluigi

    2016-04-01

    The problem of two colliding and counter-propagating Alfvénic wave packets has been investigated in detail since the late Seventies. In particular Moffatt [1] and Parker [2] showed that, in the framework of the incompressible magnetohydrodynamics (MHD), nonlinear interactions can develop only during the overlapping of the two packets. Here we describe a similar problem in the framework of the kinetic physics. The collision of two quasi-Alfvénic packets has been analyzed by means of MHD, Hall-MHD and kinetic simulations performed with two different hybrid codes: a PIC code [3] and a Vlasov-Maxwell code [4]. Due to the huge computational cost, only a 2D-3V phase space is allowed (two dimensions in the physical space, three dimensions in the velocity space). Preliminary results suggest that, as well as in the MHD case, the most relevant nonlinear effects occur during the overlapping of the two packets. For both the PIC and Vlasov cases, strong temperature anisotropies are present during the evolution of the wave packets. Moreover, due to the absence of numerical noise, Vlasov simulations show that the collision of the counter-propagating solitary waves produces a significant beam in the velocity distribution functions [5], which, instead, cannot be appreciated in PIC simulations. We remark that, beyond the interest of studying a well-known MHD problem in the realm of the kinetic physics, our results allows also to compare different numerical codes. [1] H.K. Moffatt, Field generation in electrically conducting fluids (Cambridge University Press, 1978). [2] E.N. Parker, Cosmical magnetic fields: their origin and their activity (Oxford University Press, 1979). [3] T.N. Parashar, M.A. Shay, P.A. Cassak and W.H. Matthaeus, Physics of Plasmas 16, 032310 (2009). [4] F. Valentini, P. Trávníček, F. Califano, P. Hellinger & A. Mangeney, Journal of Computational Physics 225, 753-770 (2007). [5] J. He, C. Tu, E. Marsch, C.H. Chen, L. Wang, Z. Pei, L. Zhang, C.S. Salem and S

  19. Early Childhood Motor Skills Information Packet.

    ERIC Educational Resources Information Center

    Juelsgaard, Cheri

    This activity book is designed to assist teachers in enhancing preschool children's motor skills, physical development, and social skills, and to build young children's self-esteem. The activities are designed for both disabled and nondisabled children. The first section of the book suggests specific activities in 13 categories of motor skills:…

  20. 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.

  1. 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.

  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. 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.

  4. 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…

  5. 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.

  6. 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…

  7. 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…

  8. 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...

  9. 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...

  10. 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.…

  11. 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.

  12. 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…

  13. 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."…

  14. 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…

  15. 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.

  16. "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…

  17. 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…

  18. 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)…

  19. 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…

  20. 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.

  1. 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).

  2. 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.

  3. 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…

  4. 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.

  5. 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.

  6. 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.

  7. 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…

  8. 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…

  9. 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:…

  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. Nebraska Energy Education-1982. An Evaluation.

    ERIC Educational Resources Information Center

    Scharmann, Larry

    To determine the success of Nebraska's 3-year effort in energy education, an evaluation was conducted to solicit data concerning the effectiveness of on-going energy curricula using teacher responses. These curricula include "Energy Conservation Activity Packets" (ECAP) for elementary programs and "Basic Teaching Units on Energy" (BTU) for…

  12. The Transfer Achievement Program (TAP): Information Packet.

    ERIC Educational Resources Information Center

    Segura, Armando; Noseworthy, Victoria

    Santa Barbara City College (California) created the Transfer Achievement Program (TAP) to deliver an integrated and cohesive set of services to underrepresented students to help increase their transfer rate to four-year institutions. TAP provides students with a developmental map of transfer-related activities through the use of the Transfer Task…

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. America's Hero to the World, George C. Marshall. Teacher's Guide. Second Edition [and] Resource Packet [and] George C. Marshall: An American Leader. A Teacher's Notebook.

    ERIC Educational Resources Information Center

    Thompson, Rachel Yarnell; Sittig, Linda H.

    This teaching unit about George C. Marshall contains a teacher's guide, a resource packet, and a teacher's notebook. The teacher's guide includes ten introductory, overarching, and culminating activities: (1) About this Guide; (2) Getting to Know Him; (3) Marshal on Video; (4) Share a Space with a Hero; (5) On a Global Stage--Links; (6) A Picture…

  6. Art Image Preschool: Introducing 3-to-5-Year-Old Children to Art and Artists. [Packet] 4: Animals in the Wild. Teacher's Guide.

    ERIC Educational Resources Information Center

    Thompson, Christine

    This teacher's guide accompanies a packet of five art reproductions based on animals as a theme. The guide offers suggestions for engaging children's attention and curiosity about art and artists, and encourages exploration of the issues these works present through art activities, discussions, learning centers, field trips, and other experiences…

  7. Art Image Preschool: Introducing 3-to-5-Year-Old Children to Art and Artists. [Packet] 2: Pets Are Part of Our Lives. Teacher's Guide.

    ERIC Educational Resources Information Center

    Thompson, Christine

    This teacher's guide accompanies a packet of five art reproductions based on pets as a theme. The guide offers suggestions for engaging children's attention and curiosity about art and artists, and encourages exploration of the issues these works present through art activities, discussions, learning centers, field trips, and other experiences…

  8. Art Image Preschool: Introducing 3-to-5-Year-Old Children to Art and Artists. [Packet] 3: Portraits Are Images of People. Teacher's Guide.

    ERIC Educational Resources Information Center

    Thompson, Christine

    This teacher's guide accompanies a packet of five art reproductions based on portraits as a theme. The guide offers suggestions for engaging children's attention and curiosity about art and artists, and encourages exploration of the issues these works present through art activities, discussions, learning centers, field trips, and other experiences…

  9. Art Image Preschool: Introducing 3-to-5-Year-Old Children to Art and Artists. [Packet] 1: Shapes, Colors, and Stories. Teacher's Guide.

    ERIC Educational Resources Information Center

    Thompson, Christine

    This teacher's guide accompanies a packet of five art reproductions based on the theme: shapes, colors, and stories. The guide offers suggestions for engaging children's attention and curiosity about art and artists, and encourages exploration of the issues these works present through art activities, discussions, learning centers, field trip, and…

  10. 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

  11. 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

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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)

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. Novel engineered cationic antimicrobial peptides display broad-spectrum activity against Francisella tularensis, Yersinia pestis and Burkholderia pseudomallei.

    PubMed

    Abdelbaqi, Suha; Deslouches, Berthony; Steckbeck, Jonathan; Montelaro, Ronald; Reed, Douglas S

    2016-02-01

    Broad-spectrum antimicrobials are needed to effectively treat patients infected in the event of a pandemic or intentional release of a pathogen prior to confirmation of the pathogen's identity. Engineered cationic antimicrobial peptides (eCAPs) display activity against a number of bacterial pathogens including multi-drug-resistant strains. Two lead eCAPs, WLBU2 and WR12, were compared with human cathelicidin (LL-37) against three highly pathogenic bacteria: Francisella tularensis, Yersinia pestis and Burkholderia pseudomallei. Both WLBU2 and WR12 demonstrated bactericidal activity greater than that of LL-37, particularly against F. tularensis and Y. pestis. Only WLBU2 had bactericidal activity against B. pseudomallei. WLBU2, WR12 and LL-37 were all able to inhibit the growth of the three bacteria in vitro. Because these bacteria can be facultative intracellular pathogens, preferentially infecting macrophages and dendritic cells, we evaluated the activity of WLBU2 against F. tularensis in an ex vivo infection model with J774 cells, a mouse macrophage cell line. In that model WLBU2 was able to achieve greater than 50% killing of F. tularensis at a concentration of 12.5 μM. These data show the therapeutic potential of eCAPs, particularly WLBU2, as a broad-spectrum antimicrobial for treating highly pathogenic bacterial infections. PMID:26673248

  15. 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.

  16. 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

  17. 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.

  18. 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…

  19. 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…

  20. 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.

  1. 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.

  2. 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…

  3. 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…

  4. 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.

  5. 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.

  6. 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.

  7. 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)

  8. 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…

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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

  6. 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.

  7. 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.

  8. 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.

  9. Experimental evaluation of the impact of packet capturing tools for web services.

    SciTech Connect

    Choe, Yung Ryn; Mohapatra, Prasant; Chuah, Chen-Nee; Chen, Chao-Chih

    2011-10-01

    Network measurement is a discipline that provides the techniques to collect data that are fundamental to many branches of computer science. While many capturing tools and comparisons have made available in the literature and elsewhere, the impact of these packet capturing tools on existing processes have not been thoroughly studied. While not a concern for collection methods in which dedicated servers are used, many usage scenarios of packet capturing now requires the packet capturing tool to run concurrently with operational processes. In this work we perform experimental evaluations of the performance impact that packet capturing process have on web-based services; in particular, we observe the impact on web servers. We find that packet capturing processes indeed impact the performance of web servers, but on a multi-core system the impact varies depending on whether the packet capturing and web hosting processes are co-located or not. In addition, the architecture and behavior of the web server and process scheduling is coupled with the behavior of the packet capturing process, which in turn also affect the web server's performance.

  10. Oak Ridge Environmental Information System (ORIES) site workstation information packet for OREIS V1. 2

    SciTech Connect

    Voorhees, L.D.; McCord, R.A.; Durfee, R.C.; Land, M.L.; Olson, R.J.; Palmer, M.R.; Thomas, J.K.; Tinnel, E.P.; Zygmunt, B.C.

    1993-02-01

    The OREIS site workstation information packet was developed to accompany the OREIS site workstations, which are being delivered to the Environmental Restoration programs at the five DOE-OR sites. The packet is written specifically for the Site ER program staff at each of the five Sites who have been designated the OREIS contact by their ER program manager, and is not intended for general distribution. The packet provides an overview of the components of OREIS, points to more detailed information provided in the accompanying vendor and OREIS developed manuals, and includes information on training opportunities and user support.

  11. Eliminating the dipole phase in attosecond pulse characterization using Rydberg wave packets

    NASA Astrophysics Data System (ADS)

    Pabst, Stefan; Dahlström, Jan Marcus

    2016-07-01

    We propose a technique to fully characterize the temporal structure of extreme ultraviolet pulses by ionizing a bound coherent electronic wave packet. The influence of the dipole phase, which is the main obstacle for state-of-the-art pulse characterization schemes, can be eliminated by angle integration of the photoelectron spectrum. We show that in particular, atomic Rydberg wave packets are ideal and that wave packets involving multiple electronic states provide redundant information that can be used to cross-check the consistency of the phase reconstruction.

  12. Classification of surface EMG signals using optimal wavelet packet method based on Davies-Bouldin criterion.

    PubMed

    Wang, Gang; Wang, Zhizhong; Chen, Weiting; Zhuang, Jun

    2006-10-01

    In this paper we present an optimal wavelet packet (OWP) method based on Davies-Bouldin criterion for the classification of surface electromyographic signals. To reduce the feature dimensionality of the outputs of the OWP decomposition, the principle components analysis was employed. Then we chose a neural network classifier to discriminate four types of prosthesis movements. The proposed method achieved a mean classification accuracy of 93.75%, which outperformed the method using the energy of wavelet packet coefficients (with mean classification accuracy 86.25%) and the fuzzy wavelet packet method (87.5%).

  13. 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.

  14. Reliability aspects of the future hybrid optical network and quality of service issues for real time and packet traffic

    NASA Astrophysics Data System (ADS)

    Marciniak, Marian

    2004-09-01

    While Internet traffic increases dramatically and now it exceeds the almost stable voice traffic, new efficient solutions for network architecture are sought. One of the main problems to be resolved is the basic concept of the future network performance. While actual networks are based on 'circuit switching' connection networks with IP packets forwarded given the network offers some free resources, a number of researchers foresee the future network as a 'packet switched' connectionless network which would support also the traditional real time services with phone calls as the most representative example. This is driven by the growing use of voice over IP services. Unfortunately, the Quality of Service is actually not sufficient for wide acceptance of that technique. In fact, Internet is based on the 'best-effort' principle in what it fudamentally differs from circuit-switched network which has been developed uniquely to provide excellent voice quality during last century. Moreover, the reliability of the network is a crucial factor in emergency communications, what has recently became a subject of intense activity at national and international scale. As a consequence, the idea of dropping the converged network with voice-over-IP concept is hard to accept for a great majority and those expressing it are usually looked as strange or even dangerous individuals. Nevertheless, those fundamental difficulties become obvious for a growing number of people who approach the future network evolution more fundamentally, and try to trace reasonable and economic ways of the future network development. The author of this paper has extensively developed a concept of a "hybrid network" which consists of real-time subnetwork and packet network separated in the optical frequency domain that will be discussed in detail in this paper. This optimized network concept is intended to guarantee both reliability of the network and Quality of Service as well.

  15. Wave-packet squeezing by iterative pump-dump control in diatomic molecules

    SciTech Connect

    Chang, Bo Y.; Lee, Sungyul; Sola, Ignacio R.; Santamaria, Jesus

    2006-02-15

    Iterative vibrational wave packet squeezing by a sequence of femtosecond pulses is proposed. Analytic formulas are derived for the harmonic oscillator case, and the practical implementation of the scheme is tested on different electronic transitions in Rb{sub 2}.

  16. Oriented rotational wave-packet dynamics studies via high harmonic generation.

    PubMed

    Frumker, E; Hebeisen, C T; Kajumba, N; Bertrand, J B; Wörner, H J; Spanner, M; Villeneuve, D M; Naumov, A; Corkum, P B

    2012-09-14

    We produce oriented rotational wave packets in CO and measure their characteristics via high harmonic generation. The wave packet is created using an intense, femtosecond laser pulse and its second harmonic. A delayed 800 nm pulse probes the wave packet, generating even-order high harmonics that arise from the broken symmetry induced by the orientation dynamics. The even-order harmonic radiation that we measure appears on a zero background, enabling us to accurately follow the temporal evolution of the wave packet. Our measurements reveal that, for the conditions optimum for harmonic generation, the orientation is produced by preferential ionization which depletes the sample of molecules of one orientation. PMID:23005628

  17. 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.

  18. Contentionless transmission in buffer-less slotted optical packet switched networks

    NASA Astrophysics Data System (ADS)

    Asghari, Masoud; Ghaffarpour Rahbar, Akbar

    2016-07-01

    Contention of optical packets in optical packet switched (OPS) networks is a major problem, and it is even more critical in buffer-less OPS networks. In this paper, an innovative contention avoidance technique is proposed which uses combination of special traffic shaping at ingress switches and special time slot reservation technique through the path of traffic flows in core network. This novel protocol is called contentionless transmission OPS (CLTOPS) suitable for buffer-less slotted OPS networks. Performance evaluations show that the CLTOPS can outperform the original slotted-OPS architecture in terms of packet loss rate (PLR) performance, with or without using wavelength conversion. It is shown that there is a trade-off between the amount of improvement in PLR and additional delay applied to the users' packets at the ingress switches buffers. However, appropriate parameters can be selected to make the additional delay tolerable for users' applications.

  19. Nonlinear dynamics of Airy-vortex 3D wave packets: emission of vortex light waves.

    PubMed

    Driben, Rodislav; Meier, Torsten

    2014-10-01

    The dynamics of 3D Airy-vortex wave packets is studied under the action of strong self-focusing Kerr nonlinearity. Emissions of nonlinear 3D waves out of the main wave packets with the topological charges were demonstrated. Because of the conservation of the total angular momentum, charges of the emitted waves are equal to those carried by the parental light structure. The rapid collapse imposes a severe limitation on the propagation of multidimensional waves in Kerr media. However, the structure of the Airy beam carrier allows the coupling of light from the leading, most intense peak into neighboring peaks and consequently strongly postpones the collapse. The dependence of the critical input amplitude for the appearance of a fast collapse on the beam width is studied for wave packets with zero and nonzero topological charges. Wave packets carrying angular momentum are found to be much more resistant to the rapid collapse.

  20. Discrete Packet Analysis for Improved Atmospheric Rejection on Modulated Laser Signals

    SciTech Connect

    O'Neill, M., McKenna, I., DiBenedetto, J., Capelle, G., Trainham, R.

    2012-07-19

    This slide-show discusses how the method of discrete packet analysis improves atmospheric compensation for quasi-CW fluorescence detection methods. This is key to improving remote sensing capabilities.

  1. Femtosecond wave-packet dynamics in cesium dimers studied through controlled stimulated emission

    SciTech Connect

    Yuan Luqi; Wang Xi; Patnaik, Anil K.; Sokolov, Alexei V.; Ariunbold, Gombojav O.; Murawski, Robert K.; Pestov, Dmitry; Sautenkov, Vladimir A.; Rostovtsev, Yuri V.; Scully, Marlan O.

    2010-05-15

    We study the dynamics of wave packets in cesium dimers using a femtosecond-controlled pump-probe technique. We implement configurations with one pulse (pump) or two pulses (pump and control) to produce vibrational wave packets on the electronic excited state. The transmission of an additional, variable-delay probe pulse is measured to monitor the time evolution of the wave packets. In the case of the pump-control-probe configuration, a superposition of two independent wave packets is observed. In order to elucidate the observed experimental data, we develop a theory based on the Liouville equation for the density matrix associated with the Franck-Condon factors. Both the numerical and analytical calculations are in good agreement with our experimental results.

  2. Temporal and spatial manipulation of the recolliding wave packet in strong-field photoelectron holography

    NASA Astrophysics Data System (ADS)

    He, Mingrui; Li, Yang; Zhou, Yueming; Li, Min; Lu, Peixiang

    2016-03-01

    We theoretically demonstrate temporal and spatial manipulation of electron wave packets involved in strong-field photoelectron holography (SFPH) with the orthogonally polarized two-color laser fields. By varying the relative phase of the two-color fields, the recollision time of the returning wave packet can be accurately controlled, which allows us to switch off and on the holographic interference. Moreover, the recollision angles of the returning electron wave packet can be arbitrarily controlled via changing the relative intensity of the two-color fields, and thus the structure information of the target is encoded in the hologram by the recollision electron wave packet from different angles. This makes the SFPH a powerful technique of imaging the molecular structure as well as ultrafast dynamics on an attosecond time scale.

  3. A wavelet packet adaptive filtering algorithm for enhancing manatee vocalizations.

    PubMed

    Gur, M Berke; Niezrecki, Christopher

    2011-04-01

    Approximately a quarter of all West Indian manatee (Trichechus manatus latirostris) mortalities are attributed to collisions with watercraft. A boater warning system based on the passive acoustic detection of manatee vocalizations is one possible solution to reduce manatee-watercraft collisions. The success of such a warning system depends on effective enhancement of the vocalization signals in the presence of high levels of background noise, in particular, noise emitted from watercraft. Recent research has indicated that wavelet domain pre-processing of the noisy vocalizations is capable of significantly improving the detection ranges of passive acoustic vocalization detectors. In this paper, an adaptive denoising procedure, implemented on the wavelet packet transform coefficients obtained from the noisy vocalization signals, is investigated. The proposed denoising algorithm is shown to improve the manatee detection ranges by a factor ranging from two (minimum) to sixteen (maximum) compared to high-pass filtering alone, when evaluated using real manatee vocalization and background noise signals of varying signal-to-noise ratios (SNR). Furthermore, the proposed method is also shown to outperform a previously suggested feedback adaptive line enhancer (FALE) filter on average 3.4 dB in terms of noise suppression and 0.6 dB in terms of waveform preservation.

  4. Wide-band packet radio for multipath environments

    NASA Astrophysics Data System (ADS)

    Fischer, Jeffrey H.; Cafarella, John H.; Bouman, Charles A.; Flynn, Gerard T.; Dolat, Victor S.

    1988-05-01

    A direct-sequence spread-spectrum packet radio is described that has versatile signal-processing and local-control capabilities designed to support the functions required of a robust mobile communications network. Noteworthy capabilities include eleven selectable data rates with accurate range measurements in a fading multipath channel. The radio uses a hybrid analog/digital signal processor and nonrepeating spreading codes for suppression of intersymbol interference and jamming. It incorporates two sets of monolithic surface-acoustic-wave convolvers as programmable matched filters with time-bandwidth products of 64 and 2000. The analog matched filters are coupled with binary postprocessing for the functions of detection, RAKE demodulation, and ranging measurements over a wide multipath spread. The data rate can be varied in response to channel conditions from 1.45 Mb/s down to 44 b/s with an almost ideal tradeoff in signal-processing gain from 18 dB up to 61 dB prior to multipath combining.

  5. Separated Fringe Packet Observations with the CHARA Array

    NASA Astrophysics Data System (ADS)

    Farrington, Christopher D.; ten Brummelaar, T. A.; Mason, B. D.; Hartkopf, W. I.; McAlister, H. A.; Raghavan, D.; Turner, N. H.; Sturmann, L.; Sturmann, J.; Ridgway, S. T.

    2010-01-01

    We present the modification of the orbits of several spectroscopic binarie and a completely new orbit for HD 198084, including data taken at the Center for High Angular Resolution Astronomy (CHARA) Array. These data were obtained using a modification of the little used technique of separated fringe packets (SFP). The accuracy of the SFP data surpasses that of data taken by speckle, but the technique is much more time and labor intensive. Additionally, using SFPs with the CHARA Array, it is possible to obtain separations below the detection range of speckle interferometry (>30mas) and above the range in "classic" long-baseline interferometry where fringes from a binary overlap and are no longer separated (<10mas). Using spectroscopic binary systems with published speckle orbits, we are able to test our new measurements against their ephemerides to calibrate the method as well as produce entirely new orbits for systems with no current astrometric observations. The CHARA Array, operated by Georgia State University, was built with funding provided by the National Science Foundation, Georgia State University, the W. M. Keck Foundation, and the David and Lucile Packard Foundation. This research is supported by the National Science Foundation under grant AST 0908253 as well as by funding from the office of the Dean of the College of Arts and Science at Georgia State University.

  6. Riemann {zeta} function from wave-packet dynamics

    SciTech Connect

    Mack, R.; Schleich, W. P.; Dahl, J. P.; Moya-Cessa, H.; Strunz, W. T.; Walser, R.

    2010-09-15

    We show that the time evolution of a thermal phase state of an anharmonic oscillator with logarithmic energy spectrum is intimately connected to the generalized Riemann {zeta} function {zeta}(s,a). Indeed, the autocorrelation function at a time t is determined by {zeta}({sigma}+i{tau},a), where {sigma} is governed by the temperature of the thermal phase state and {tau} is proportional to t. We use the JWKB method to solve the inverse spectral problem for a general logarithmic energy spectrum; that is, we determine a family of potentials giving rise to such a spectrum. For large distances, all potentials display a universal behavior; they take the shape of a logarithm. However, their form close to the origin depends on the value of the Hurwitz parameter a in {zeta}(s,a). In particular, we establish a connection between the value of the potential energy at its minimum, the Hurwitz parameter and the Maslov index of JWKB. We compare and contrast exact and approximate eigenvalues of purely logarithmic potentials. Moreover, we use a numerical method to find a potential which leads to exact logarithmic eigenvalues. We discuss possible realizations of Riemann {zeta} wave-packet dynamics using cold atoms in appropriately tailored light fields.

  7. A wavelet packet adaptive filtering algorithm for enhancing manatee vocalizations.

    PubMed

    Gur, M Berke; Niezrecki, Christopher

    2011-04-01

    Approximately a quarter of all West Indian manatee (Trichechus manatus latirostris) mortalities are attributed to collisions with watercraft. A boater warning system based on the passive acoustic detection of manatee vocalizations is one possible solution to reduce manatee-watercraft collisions. The success of such a warning system depends on effective enhancement of the vocalization signals in the presence of high levels of background noise, in particular, noise emitted from watercraft. Recent research has indicated that wavelet domain pre-processing of the noisy vocalizations is capable of significantly improving the detection ranges of passive acoustic vocalization detectors. In this paper, an adaptive denoising procedure, implemented on the wavelet packet transform coefficients obtained from the noisy vocalization signals, is investigated. The proposed denoising algorithm is shown to improve the manatee detection ranges by a factor ranging from two (minimum) to sixteen (maximum) compared to high-pass filtering alone, when evaluated using real manatee vocalization and background noise signals of varying signal-to-noise ratios (SNR). Furthermore, the proposed method is also shown to outperform a previously suggested feedback adaptive line enhancer (FALE) filter on average 3.4 dB in terms of noise suppression and 0.6 dB in terms of waveform preservation. PMID:21476661

  8. Coriolis-coupled wave packet dynamics of H + HLi reaction.

    PubMed

    Padmanaban, R; Mahapatra, S

    2006-05-11

    We investigated the effect of Coriolis coupling (CC) on the initial state-selected dynamics of H+HLi reaction by a time-dependent wave packet (WP) approach. Exact quantum scattering calculations were obtained by a WP propagation method based on the Chebyshev polynomial scheme and ab initio potential energy surface of the reacting system. Partial wave contributions up to the total angular momentum J=30 were found to be necessary for the scattering of HLi in its vibrational and rotational ground state up to a collision energy approximately 0.75 eV. For each J value, the projection quantum number K was varied from 0 to min (J, K(max)), with K(max)=8 until J=20 and K(max)=4 for further higher J values. This is because further higher values of K do not have much effect on the dynamics and also because one wishes to maintain the large computational overhead for each calculation within the affordable limit. The initial state-selected integral reaction cross sections and thermal rate constants were calculated by summing up the contributions from all partial waves. These were compared with our previous results on the title system, obtained within the centrifugal sudden and J-shifting approximations, to demonstrate the impact of CC on the dynamics of this system.

  9. Discrete wave-packet representation in nuclear matter calculations

    NASA Astrophysics Data System (ADS)

    Müther, H.; Rubtsova, O. A.; Kukulin, V. I.; Pomerantsev, V. N.

    2016-08-01

    The Lippmann-Schwinger equation for the nucleon-nucleon t matrix as well as the corresponding Bethe-Goldstone equation to determine the Brueckner reaction matrix in nuclear matter are reformulated in terms of the resolvents for the total two-nucleon Hamiltonians defined in free space and in medium correspondingly. This allows one to find solutions at many energies simultaneously by using the respective Hamiltonian matrix diagonalization in the stationary wave-packet basis. Among other important advantages, this approach simplifies greatly the whole computation procedures both for the coupled-channel t matrix and the Brueckner reaction matrix. Therefore this principally novel scheme is expected to be especially useful for self-consistent nuclear matter calculations because it allows one to accelerate in a high degree single-particle potential iterations. Furthermore the method provides direct access to the properties of possible two-nucleon bound states in the nuclear medium. The comparison between reaction matrices found via the numerical solution of the Bethe-Goldstone integral equation and the straightforward Hamiltonian diagonalization shows a high accuracy of the method suggested. The proposed fully discrete approach opens a new way to an accurate treatment of two- and three-particle correlations in nuclear matter on the basis of the three-particle Bethe-Faddeev equation by an effective Hamiltonian diagonalization procedure.

  10. Method and apparatus for routing data in an inter-nodal communications lattice of a massively parallel computer system by semi-randomly varying routing policies for different packets

    DOEpatents

    Archer, Charles Jens; Musselman, Roy Glenn; Peters, Amanda; Pinnow, Kurt Walter; Swartz, Brent Allen; Wallenfelt, Brian Paul

    2010-11-23

    A massively parallel computer system contains an inter-nodal communications network of node-to-node links. Nodes vary a choice of routing policy for routing data in the network in a semi-random manner, so that similarly situated packets are not always routed along the same path. Semi-random variation of the routing policy tends to avoid certain local hot spots of network activity, which might otherwise arise using more consistent routing determinations. Preferably, the originating node chooses a routing policy for a packet, and all intermediate nodes in the path route the packet according to that policy. Policies may be rotated on a round-robin basis, selected by generating a random number, or otherwise varied.

  11. Beam dynamics and wave packet splitting in a periodically curved optical waveguide: multimode effects.

    PubMed

    Marangoni, M; Janner, D; Ramponi, R; Laporta, P; Longhi, S; Cianci, E; Foglietti, V

    2005-08-01

    A theoretical and experimental analysis of beam dynamics and wave packet splitting of light in a periodically bent optical waveguide, a phenomenon recently observed [Phys. Rev. Lett. 94, 073002 (2005)] which is the optical equivalent of adiabatic stabilization of atoms in intense and high-frequency laser fields, is presented in the multimode operational regime. Inhibition of wave packet splitting is theoretically predicted and experimentally observed for higher-order mode excitation.

  12. New hybrid frequency reuse method for packet loss minimization in LTE network.

    PubMed

    Ali, Nora A; El-Dakroury, Mohamed A; El-Soudani, Magdi; ElSayed, Hany M; Daoud, Ramez M; Amer, Hassanein H

    2015-11-01

    This paper investigates the problem of inter-cell interference (ICI) in Long Term Evolution (LTE) mobile systems, which is one of the main problems that causes loss of packets between the base station and the mobile station. Recently, different frequency reuse methods, such as soft and fractional frequency reuse, have been introduced in order to mitigate this type of interference. In this paper, minimizing the packet loss between the base station and the mobile station is the main concern. Soft Frequency Reuse (SFR), which is the most popular frequency reuse method, is examined and the amount of packet loss is measured. In order to reduce packet loss, a new hybrid frequency reuse method is implemented. In this method, each cell occupies the same bandwidth of the SFR, but the total system bandwidth is greater than in SFR. This will provide the new method with a lot of new sub-carriers from the neighboring cells to reduce the ICI which represents a big problem in many applications and causes a lot of packets loss. It is found that the new hybrid frequency reuse method has noticeable improvement in the amount of packet loss compared to SFR method in the different frequency bands. Traffic congestion management in Intelligent Transportation system (ITS) is one of the important applications that is affected by the packet loss due to the large amount of traffic that is exchanged between the base station and the mobile node. Therefore, it is used as a studied application for the proposed frequency reuse method and the improvement in the amount of packet loss reached 49.4% in some frequency bands using the new hybrid frequency reuse method.

  13. Image encryption algorithm based on wavelet packet decomposition and discrete linear canonical transform

    NASA Astrophysics Data System (ADS)

    Sharma, K. K.; Jain, Heena

    2013-01-01

    The security of digital data including images has attracted more attention recently, and many different image encryption methods have been proposed in the literature for this purpose. In this paper, a new image encryption method using wavelet packet decomposition and discrete linear canonical transform is proposed. The use of wavelet packet decomposition and DLCT increases the key size significantly making the encryption more robust. Simulation results of the proposed technique are also presented.

  14. Generation of attosecond electron packets via conical surface plasmon electron acceleration

    PubMed Central

    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. PMID:26764129

  15. New hybrid frequency reuse method for packet loss minimization in LTE network.

    PubMed

    Ali, Nora A; El-Dakroury, Mohamed A; El-Soudani, Magdi; ElSayed, Hany M; Daoud, Ramez M; Amer, Hassanein H

    2015-11-01

    This paper investigates the problem of inter-cell interference (ICI) in Long Term Evolution (LTE) mobile systems, which is one of the main problems that causes loss of packets between the base station and the mobile station. Recently, different frequency reuse methods, such as soft and fractional frequency reuse, have been introduced in order to mitigate this type of interference. In this paper, minimizing the packet loss between the base station and the mobile station is the main concern. Soft Frequency Reuse (SFR), which is the most popular frequency reuse method, is examined and the amount of packet loss is measured. In order to reduce packet loss, a new hybrid frequency reuse method is implemented. In this method, each cell occupies the same bandwidth of the SFR, but the total system bandwidth is greater than in SFR. This will provide the new method with a lot of new sub-carriers from the neighboring cells to reduce the ICI which represents a big problem in many applications and causes a lot of packets loss. It is found that the new hybrid frequency reuse method has noticeable improvement in the amount of packet loss compared to SFR method in the different frequency bands. Traffic congestion management in Intelligent Transportation system (ITS) is one of the important applications that is affected by the packet loss due to the large amount of traffic that is exchanged between the base station and the mobile node. Therefore, it is used as a studied application for the proposed frequency reuse method and the improvement in the amount of packet loss reached 49.4% in some frequency bands using the new hybrid frequency reuse method. PMID:26644933

  16. Trajectory description of the quantum-classical transition for wave packet interference

    NASA Astrophysics Data System (ADS)

    Chou, Chia-Chun

    2016-08-01

    The quantum-classical transition for wave packet interference is investigated using a hydrodynamic description. A nonlinear quantum-classical transition equation is obtained by introducing a degree of quantumness ranging from zero to one into the classical time-dependent Schrödinger equation. This equation provides a continuous description for the transition process of physical systems from purely quantum to purely classical regimes. In this study, the transition trajectory formalism is developed to provide a hydrodynamic description for the quantum-classical transition. The flow momentum of transition trajectories is defined by the gradient of the action function in the transition wave function and these trajectories follow the main features of the evolving probability density. Then, the transition trajectory formalism is employed to analyze the quantum-classical transition of wave packet interference. For the collision-like wave packet interference where the propagation velocity is faster than the spreading speed of the wave packet, the interference process remains collision-like for all the degree of quantumness. However, the interference features demonstrated by transition trajectories gradually disappear when the degree of quantumness approaches zero. For the diffraction-like wave packet interference, the interference process changes continuously from a diffraction-like to collision-like case when the degree of quantumness gradually decreases. This study provides an insightful trajectory interpretation for the quantum-classical transition of wave packet interference.

  17. 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

  18. General Solution for Theoretical Packet Data Loss Rate

    NASA Technical Reports Server (NTRS)

    Lansdowne, Chatwin; Schlesinger, Adam

    2006-01-01

    Communications systems which transfer blocks ("frames") of data must use a marker ("frame synchronization pattern") for identifying where a block begins. A technique ("frame synchronization strategy") is used to locate the start of each frame and maintain synchronization as additional blocks are processed. A device which strips out the frame synchronization pattern [FSP] and provides an "end of frame" pulse is called a frame synchronizer. As clock and data errors are introduced into the system, the start-of-block marker becomes displaced and/or corrupted. The capability of the frame synchronizer to stay locked to the pattern under these conditions is a figure of merit for the frame synchronization strategy. It is important to select a strategy which will stay locked nearly all the time at bit error rates where the data is usable. ("Bit error rate" [BER] is the fraction of binary bits which are inverted by passage through a communication system.) The fraction of frames that are discarded because the frame synchronizer is not locked is called "Percent Data Loss" or "Packet Data Loss rate" [PDL]. A general approach for accurately predicting PDL given BER was developed in Theoretical Percent Data Loss Calculation and Measurement Accuracy, T. P. Kelly, LESC-30554, December 1992. Kelly gave a solution in terms of matrix equations, and only addressed "level" channel encoding. This paper goes on to give a closed-form polynomial solution for the most common class of frame synchronizer strategies, and will also address "mark" and "space" (differential) channel encoding, and burst error environments. The paper is divided into four sections and follows a logically ordered presentation, with results developed before they are evaluated. However, most readers will derive the greatest benefit from this paper by treating the results as reference material. The result developed for differential encoding can be extended to other applications (like block codes) where the probability is

  19. A Packet Loss Concealment Algorithm Robust to Burst Packet Loss Using Multiple Codebooks and Comfort Noise for CELP-Type Speech Coders

    NASA Astrophysics Data System (ADS)

    Park, Nam In; Kim, Hong Kook; Jung, Min A.; Lee, Seong Ro; Choi, Seung Ho

    In this paper, a packet loss concealment (PLC) algorithm for CELP-type speech coders is proposed to improve the quality of decoded speech under burst packet loss. A conventional PLC algorithm is usually based on speech correlation to reconstruct decoded speech of lost frames by using the information on the parameters obtained from the previous frames that are assumed to be correctly received. However, this approach is apt to fail to reconstruct voice onset signals since the parameters such as pitch, LPC coefficient, and adaptive/fixed codebooks of the previous frames are almost related to silence frames. Thus, in order to reconstruct speech signals in the voice onset intervals, we propose a multiple codebook based approach which includes a traditional adaptive codebook and a new random codebook composed of comfort noise. The proposed PLC algorithm is designed as a PLC algorithm for G.729 and its performance is then compared with that of the PLC algorithm employed in G.729 by means of perceptual evaluation of speech quality (PESQ), a waveform comparison, and an A-B preference test under different random and burst packet loss conditions. It is shown from the experiments that the proposed PLC algorithm provides significantly better speech quality than the PLC of G.729, especially under burst packet loss and voice onset conditions.

  20. Optical control of molecular dynamics: Molecular cannons, reflectrons, and wave-packet focusers

    NASA Astrophysics Data System (ADS)

    Krause, Jeffrey L.; Whitnell, Robert M.; Wilson, Kent R.; Yan, YiJing; Mukamel, Shaul

    1993-11-01

    We consider the control of molecular dynamics using tailored light fields, based on a phase space theory of control [Y. J. Yan et al., J. Phys. Chem. 97, 2320 (1993)]. This theory enables us to calculate, in the weak field (one-photon) limit, the globally optimal light field that produces the best overlap for a given phase space target. We present as an illustrative example the use of quantum control to overcome the natural tendency of quantum wave packets to delocalize on excited state potential energy curves. Three cases are studied: (i) a ``molecular cannon'' in which we focus an outgoing continuum wave packet of I2 in both position and momentum, (ii) a ``reflectron'' in which we focus an incoming bound wave packet of I2, and (iii) the focusing of a bound wave packet of Na2 at a turning point on the excited state potential using multiple light pulses to create a localized wave packet with zero momentum. For each case, we compute the globally optimal light field and also how well the wave packet produced by this light field achieves the desired target. These globally optimal fields are quite simple and robust. While our theory provides the globally optimal light field in the linear, weak field regime, experiment can in reality only provide a restricted universe of possible light fields. We therefore also consider the control of molecular quantum dynamics using light fields restricted to a parametrized functional form which spans a set of fields that can be experimentally realized. We fit the globally optimal electric field with a functional form consisting of a superposition of subpulses with variable parameters of amplitude, center time, center frequency, temporal width, relative phase, and linear and quadratic chirp. The best fit light fields produce excellent quantum control and are within the range of experimental possibility. We discuss relevant experiments such as ultrafast spectroscopy and ultrafast electron and x-ray diffraction which can in principle

  1. 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.

  2. [Positive Activities Campaign.

    ERIC Educational Resources Information Center

    Substance Abuse and Mental Health Services Administration (DHHS/PHS), Rockville, MD. Center for Substance Abuse Prevention.

    This packet contains four pamphlets that are part of a campaign to encourage adults to provide and promote positive activities for youth and to serve as role models for young people. "Positive Activities: A Campaign for Youth" includes information on what positive activities are, how to get involved in helping to provide positive activities for…

  3. Phase Structure of Strong-Field Tunneling Wave Packets from Molecules

    NASA Astrophysics Data System (ADS)

    Liu, Ming-Ming; Li, Min; Wu, Chengyin; Gong, Qihuang; Staudte, André; Liu, Yunquan

    2016-04-01

    We study the phase structure of the tunneling wave packets from strong-field ionization of molecules and present a molecular quantum-trajectory Monte Carlo model to describe the laser-driven dynamics of photoelectron momentum distributions of molecules. Using our model, we reproduce and explain the alignment-dependent molecular frame photoelectron spectra of strong-field tunneling ionization of N2 reported by M. Meckel et al. [Nat. Phys. 10, 594 (2014)]. In addition to modeling the low-energy photoelectron angular distributions quantitatively, we extract the phase structure of strong-field molecular tunneling wave packets, shedding light on its physical origin. The initial phase of the tunneling wave packets at the tunnel exit depends on both the initial transverse momentum distribution and the molecular internuclear distance. We further show that the ionizing molecular orbital has a critical effect on the initial phase of the tunneling wave packets. The phase structure of the photoelectron wave packet is a key ingredient for modeling strong-field molecular photoelectron holography, high-harmonic generation, and molecular orbital imaging.

  4. Rotating wave packet caused by the superposition of two Bessel-Gauss beams

    NASA Astrophysics Data System (ADS)

    Zheng, Shuiqin; Cai, Yi; Li, Ying; Li, Jingzhen; Zheng, Guoliang; Chen, Hongyi; Xu, Shixiang

    2015-12-01

    This paper presents, theoretically, a rotating wave packet by overlapping two Bessel-Gauss beams with different longitudinal wave vectors and topological charges. Our results show that the angular velocity of this kind of packet varies with propagating distance, and that Gauss amplitude modulation thus depends strongly on the Fresnel number N f. In the far field, the angular velocity of the packet tends to zero, so the packet will no longer rotate. If N f > 3.18, the packet will rotate with a constant velocity or have a stable rotating velocity along the propagation distance. Interestingly, if appropriate Gauss waist size and propagating distance z are chosen so that 0.006 < N f < 3.18, both the amplitude and the direction of the rotating angular velocity can be manipulated for given topological charges and longitudinal wave vectors. The small Gauss waist radius can induce angular velocity dispersion, causing radial rotation with out-sync and thereby the phase distortion of the BG beam.

  5. Support for non-locking parallel reception of packets belonging to a single memory reception FIFO

    DOEpatents

    Chen, Dong; Heidelberger, Philip; Salapura, Valentina; Senger, Robert M.; Steinmacher-Burow, Burkhard; Sugawara, Yutaka

    2011-01-27

    A method and apparatus for distributed parallel messaging in a parallel computing system. A plurality of DMA engine units are configured in a multiprocessor system to operate in parallel, one DMA engine unit for transferring a current packet received at a network reception queue to a memory location in a memory FIFO (rmFIFO) region of a memory. A control unit implements logic to determine whether any prior received packet destined for that rmFIFO is still in a process of being stored in the associated memory by another DMA engine unit of the plurality, and prevent the one DMA engine unit from indicating completion of storing the current received packet in the reception memory FIFO (rmFIFO) until all prior received packets destined for that rmFIFO are completely stored by the other DMA engine units. Thus, there is provided non-locking support so that multiple packets destined for a single rmFIFO are transferred and stored in parallel to predetermined locations in a memory.

  6. On the fly all-optical packet switching based on hybrid WDM/OCDMA labeling scheme

    NASA Astrophysics Data System (ADS)

    Brahmi, Houssem; Giannoulis, Giannis; Menif, Mourad; Katopodis, Vasilis; Kalavrouziotis, Dimitrios; Kouloumentas, Christos; Groumas, Panos; Kanakis, Giannis; Stamatiadis, Christos; Avramopoulos, Hercules; Erasme, Didier

    2014-02-01

    We introduce a novel design of an all-optical packet routing node that allows for the selection and forwarding of optical packets based on the routing information contained in hybrid wavelength division multiplexing/optical code division multiple access (WDM/OCDMA) labels. A stripping paradigm of optical code-label is adopted. The router is built around an optical-code gate that consists in an optical flip-flop controlled by two fiber Bragg grating correlators and is combined with a Mach-Zehnder interferometer (MZI)-based forwarding gate. We experimentally verify the proof-of-principle operation of the proposed self-routing node under NRZ and OCDMA packet traffic conditions. The successful switching of elastic NRZ payload at 40 Gb/s controlled by DS-OCDMA coded labels and the forwarding operation of encoded data using EQC codes are presented. Proper auto-correlation functions are obtained with higher than 8.1 dB contrast ratio, suitable to efficiently trigger the latching device with a contrast ratio of 11.6 dB and switching times below 3.8 ns. Error-free operation is achieved with 1.5 dB penalty for 40 Gb/s NRZ data and with 2.1 dB penalty for DS-OCDMA packets. The scheme can further be applied to large-scale optical packet switching networks by exploiting efficient optical coders allocated at different WDM channels.

  7. A Hybrid CPU/GPU Pattern-Matching Algorithm for Deep Packet Inspection.

    PubMed

    Lee, Chun-Liang; Lin, Yi-Shan; Chen, Yaw-Chung

    2015-01-01

    The large quantities of data now being transferred via high-speed networks have made deep packet inspection indispensable for security purposes. Scalable and low-cost signature-based network intrusion detection systems have been developed for deep packet inspection for various software platforms. Traditional approaches that only involve central processing units (CPUs) are now considered inadequate in terms of inspection speed. Graphic processing units (GPUs) have superior parallel processing power, but transmission bottlenecks can reduce optimal GPU efficiency. In this paper we describe our proposal for a hybrid CPU/GPU pattern-matching algorithm (HPMA) that divides and distributes the packet-inspecting workload between a CPU and GPU. All packets are initially inspected by the CPU and filtered using a simple pre-filtering algorithm, and packets that might contain malicious content are sent to the GPU for further inspection. Test results indicate that in terms of random payload traffic, the matching speed of our proposed algorithm was 3.4 times and 2.7 times faster than those of the AC-CPU and AC-GPU algorithms, respectively. Further, HPMA achieved higher energy efficiency than the other tested algorithms.

  8. Phase Structure of Strong-Field Tunneling Wave Packets from Molecules.

    PubMed

    Liu, Ming-Ming; Li, Min; Wu, Chengyin; Gong, Qihuang; Staudte, André; Liu, Yunquan

    2016-04-22

    We study the phase structure of the tunneling wave packets from strong-field ionization of molecules and present a molecular quantum-trajectory Monte Carlo model to describe the laser-driven dynamics of photoelectron momentum distributions of molecules. Using our model, we reproduce and explain the alignment-dependent molecular frame photoelectron spectra of strong-field tunneling ionization of N_{2} reported by M. Meckel et al. [Nat. Phys. 10, 594 (2014)]. In addition to modeling the low-energy photoelectron angular distributions quantitatively, we extract the phase structure of strong-field molecular tunneling wave packets, shedding light on its physical origin. The initial phase of the tunneling wave packets at the tunnel exit depends on both the initial transverse momentum distribution and the molecular internuclear distance. We further show that the ionizing molecular orbital has a critical effect on the initial phase of the tunneling wave packets. The phase structure of the photoelectron wave packet is a key ingredient for modeling strong-field molecular photoelectron holography, high-harmonic generation, and molecular orbital imaging.

  9. A Hybrid CPU/GPU Pattern-Matching Algorithm for Deep Packet Inspection

    PubMed Central

    Chen, Yaw-Chung

    2015-01-01

    The large quantities of data now being transferred via high-speed networks have made deep packet inspection indispensable for security purposes. Scalable and low-cost signature-based network intrusion detection systems have been developed for deep packet inspection for various software platforms. Traditional approaches that only involve central processing units (CPUs) are now considered inadequate in terms of inspection speed. Graphic processing units (GPUs) have superior parallel processing power, but transmission bottlenecks can reduce optimal GPU efficiency. In this paper we describe our proposal for a hybrid CPU/GPU pattern-matching algorithm (HPMA) that divides and distributes the packet-inspecting workload between a CPU and GPU. All packets are initially inspected by the CPU and filtered using a simple pre-filtering algorithm, and packets that might contain malicious content are sent to the GPU for further inspection. Test results indicate that in terms of random payload traffic, the matching speed of our proposed algorithm was 3.4 times and 2.7 times faster than those of the AC-CPU and AC-GPU algorithms, respectively. Further, HPMA achieved higher energy efficiency than the other tested algorithms. PMID:26437335

  10. A novel timestamp based adaptive clock method for circuit emulation service over packet network

    NASA Astrophysics Data System (ADS)

    Dai, Jin-you; Yu, Shao-hua

    2007-11-01

    It is necessary to transport TDM (time division multiplexing) over packet network such as IP and Ethernet, and synchronization is a problem when carrying TDM over the packet network. Clock methods for TDM over packet network are introduced. A new adaptive clock method is presented. The method is a kind of timestamp based adaptive method, but no timestamp needs transporting over packet network. By using the local oscillator and a counter, the timestamp information (local timestamp) related to the service clock of the remote PE (provide edge) and the near PE can be attained. By using D-EWMA filter algorithm, the noise caused by packet network can be filtered and the useful timestamp can be extracted out. With the timestamp and a voltage-controlled oscillator, clock frequency of near PE can be adjusted the same as clock frequency of the remote PE. A kind of simulation device is designed and a test network topology is set up to test and verify the method. The experiment result shows that synthetical performance of the new method is better than ordinary buffer based method and ordinary timestamp based method.

  11. Higher order dispersion in the propagation of a gravity wave packet

    NASA Technical Reports Server (NTRS)

    Yeh, K. C.; Dong, B.

    1989-01-01

    To the first order of approximation, the complex amplitude of a wave packet in an anisotropic and dispersive medium is convected with the group of velocity. However, a gravity wave is a vector wave. Its wave packet must be formed by superposition of various wave numbers with corresponding frequencies, as is the case for scalar waves, and additionally by superposing many eigenmodes which also depend on the wave number. To represent the vector wave packet self-consistently, it is found that a gradient term must be included in the expansion. For a Guassian wave packet, this gradient term is shown to have important implications on the velocity vector as represented by its hodograph. Numerical results show that the hodograph is influenced by the location of the relative position of interest from the center of a Gaussian pulse. Higher order expansion shows that an initial Gaussian wave packet will retain its Gaussian shape as it propagates, but the pulse will spread in all directions with its major axis undergoing a rotation. Numerical results indicate that these higher order dispersive effects may be marginally observable in the atmosphere.

  12. Parametric Packet-Layer Model for Evaluation Audio Quality in Multimedia Streaming Services

    NASA Astrophysics Data System (ADS)

    Egi, Noritsugu; Hayashi, Takanori; Takahashi, Akira

    We propose a parametric packet-layer model for monitoring audio quality in multimedia streaming services such as Internet protocol television (IPTV). This model estimates audio quality of experience (QoE) on the basis of quality degradation due to coding and packet loss of an audio sequence. The input parameters of this model are audio bit rate, sampling rate, frame length, packet-loss frequency, and average burst length. Audio bit rate, packet-loss frequency, and average burst length are calculated from header information in received IP packets. For sampling rate, frame length, and audio codec type, the values or the names used in monitored services are input into this model directly. We performed a subjective listening test to examine the relationships between these input parameters and perceived audio quality. The codec used in this test was the Advanced Audio Codec-Low Complexity (AAC-LC), which is one of the international standards for audio coding. On the basis of the test results, we developed an audio quality evaluation model. The verification results indicate that audio quality estimated by the proposed model has a high correlation with perceived audio quality.

  13. Encoding Odorant Identity by Spiking Packets of Rate-Invariant Neurons in Awake Mice

    PubMed Central

    Gschwend, Olivier; Beroud, Jonathan; Carleton, Alan

    2012-01-01

    Background How do neural networks encode sensory information? Following sensory stimulation, neural coding is commonly assumed to be based on neurons changing their firing rate. In contrast, both theoretical works and experiments in several sensory systems showed that neurons could encode information as coordinated cell assemblies by adjusting their spike timing and without changing their firing rate. Nevertheless, in the olfactory system, there is little experimental evidence supporting such model. Methodology/Principal Findings To study these issues, we implanted tetrodes in the olfactory bulb of awake mice to record the odorant-evoked activity of mitral/tufted (M/T) cells. We showed that following odorant presentation, most M/T neurons do not significantly change their firing rate over a breathing cycle but rather respond to odorant stimulation by redistributing their firing activity within respiratory cycles. In addition, we showed that sensory information can be encoded by cell assemblies composed of such neurons, thus supporting the idea that coordinated populations of globally rate-invariant neurons could be efficiently used to convey information about the odorant identity. We showed that different coding schemes can convey high amount of odorant information for specific read-out time window. Finally we showed that the optimal readout time window corresponds to the duration of gamma oscillations cycles. Conclusion We propose that odorant can be encoded by population of cells that exhibit fine temporal tuning of spiking activity while displaying weak or no firing rate change. These cell assemblies may transfer sensory information in spiking packets sequence using the gamma oscillations as a clock. This would allow the system to reach a tradeoff between rapid and accurate odorant discrimination. PMID:22272291

  14. Adaptive Control of the Packet Transmission Period with Solar Energy Harvesting Prediction in Wireless Sensor Networks

    PubMed Central

    Kwon, Kideok; Yang, Jihoon; Yoo, Younghwan

    2015-01-01

    A number of research works has studied packet scheduling policies in energy scavenging wireless sensor networks, based on the predicted amount of harvested energy. Most of them aim to achieve energy neutrality, which means that an embedded system can operate perpetually while meeting application requirements. Unlike other renewable energy sources, solar energy has the feature of distinct periodicity in the amount of harvested energy over a day. Using this feature, this paper proposes a packet transmission control policy that can enhance the network performance while keeping sensor nodes alive. Furthermore, this paper suggests a novel solar energy prediction method that exploits the relation between cloudiness and solar radiation. The experimental results and analyses show that the proposed packet transmission policy outperforms others in terms of the deadline miss rate and data throughput. Furthermore, the proposed solar energy prediction method can predict more accurately than others by 6.92%. PMID:25919372

  15. Moving the boundary between wavelength resources in optical packet and circuit integrated ring network.

    PubMed

    Furukawa, Hideaki; Miyazawa, Takaya; Wada, Naoya; Harai, Hiroaki

    2014-01-13

    Optical packet and circuit integrated (OPCI) networks provide both optical packet switching (OPS) and optical circuit switching (OCS) links on the same physical infrastructure using a wavelength multiplexing technique in order to deal with best-effort services and quality-guaranteed services. To immediately respond to changes in user demand for OPS and OCS links, OPCI networks should dynamically adjust the amount of wavelength resources for each link. We propose a resource-adjustable hybrid optical packet/circuit switch and transponder. We also verify that distributed control of resource adjustments can be applied to the OPCI ring network testbed we developed. In cooperation with the resource adjustment mechanism and the hybrid switch and transponder, we demonstrate that automatically allocating a shared resource and moving the wavelength resource boundary between OPS and OCS links can be successfully executed, depending on the number of optical paths in use. PMID:24514964

  16. Nonlinear plasma-assisted collapse of ring-Airy wave packets

    NASA Astrophysics Data System (ADS)

    Panagiotopoulos, Paris; Couairon, Arnaud; Kolesik, Miroslav; Papazoglou, Dimitris G.; Moloney, Jerome V.; Tzortzakis, Stelios

    2016-03-01

    We numerically demonstrate that femtosecond ring-Airy wave packets are able to overcome the reference intensity clamping of 4 ×1013 W/cm2 for filaments generated with Gaussian beams at low numerical apertures and form an intense sharp intensity peak on axis. Numerical simulations, with unidirectional propagation models for the pulse envelope and the carrier resolved electric field, reveal that the driving mechanism for this unexpected intensity increase is due to the self-generated plasma. The plasma formation, in conjunction with the circular geometry of the beam, force the wave packet into a multistage collapse process which takes place faster than the saturating mechanisms can compensate. We report here a nonstandard mechanism that increases the intensity of a collapsing wave packet, due to the joint contributions of the cubic phase of the Airy beam and the formation of a partially reflecting plasma.

  17. Packet Format Design and Decision Directed Tracking Methods for Filter Bank Multicarrier Systems

    NASA Astrophysics Data System (ADS)

    Amini, Peiman; Farhang-Boroujeny, Behrouz

    2010-12-01

    Packetized data transmission is commonly used in wireless communication systems. Each packet starts with a preamble which is used to synchronize the receiver with carrier frequency of the incoming signal, to find a good timing phase, and to identify the channel impulse response or to adjust a set of channel equalizer parameters. In this paper, following the same philosophy, we develop a packet format for multicarrier systems that operate based on filter banks, filter bank multicarrier (FBMC) systems. The related algorithms for carrier frequency and timing recovery as well as channel identification/equalizer adjustment and methods for carrier and timing tracking loops are proposed. The proposed ideas are evaluated and their satisfactory performance are presented through computer simulations.

  18. Observing the phase space trajectory of an entangled matter wave packet.

    PubMed

    Poschinger, U; Walther, A; Singer, K; Schmidt-Kaler, F

    2010-12-31

    We observe the phase space trajectory of an entangled wave packet of a trapped ion with high precision. The application of a spin-dependent light force on a superposition of spin states allows for coherent splitting of the matter wave packet such that two distinct components in phase space emerge. We observe such motion with a precision of better than 9% of the wave packet extension in both momentum and position, corresponding to a 0.8 nm position resolution. We accurately study the effect of the initial ion temperature on the quantum entanglement dynamics. Furthermore, we map out the phonon distributions throughout the action of the displacement force. Our investigation shows corrections to simplified models of the system evolution. The precise knowledge of these dynamics may improve quantum gates for ion crystals and lead to entangled matter wave states with large displacements. PMID:21231660

  19. Application of knowledge-based network management techniques for packet radio networks

    NASA Astrophysics Data System (ADS)

    Doyle, R. J.; Sastry, A. R. K.

    The authors developed a preliminary version of a knowledge-based model for network management and reconfiguration using blackboard techniques and have applied it to packet radio networks. The analysis is concerned with developing procedures for evaluation of candidate recovery/reconfiguration methodologies and techniques for fault isolation and related monitoring functions. As an initial step, the generic blackboard was chosen as the artificial intelligence environment to develop the management tools and interlink it to a packet radio network simulator that was used as a testbed network to be controlled and monitored. The details of the interaction of the management environment and the packet radio simulator as implemented in the model so far, and present numerical results obtained through the execution of some preliminary rules are described.

  20. A simple packet retransmission strategy for throughput and delay enhancement on power line communication channels

    SciTech Connect

    Onunga, J.O. ); Donaldson, R.W. . Dept. of Electrical Engineering)

    1993-07-01

    A new, simple, and effective communication protocol is developed and evaluated for use on power line distribution networks. The protocol involves retransmission of unacknowledged packets, which are sent in either single or multiple (N) copies in accordance with estimates of communication link quality. Multiple packet copies can be code combined at the receiver, using majority voting on each bit position, to reduce packet error rates. Adaptive link quality estimates are based on the receipt or absence of positive acknowledgements. Information throughput efficiency is calculated and N optimized in terms of system variables. Performance benefits of code combining are clearly demonstrated. The algorithm was implemented and tested using a five-station intrabuilding power line communications network operating at 1.2, 2.4, 4.8 and 9.6 kbit/s data rate. Substantial throughput and delay improvement occurred on poor quality links, without degrading performance on good links.

  1. 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.

  2. Observer-based H(infinity) control for networked nonlinear systems with random packet losses.

    PubMed

    Li, Jian Guo; Yuan, Jing Qi; Lu, Jun Guo

    2010-01-01

    This paper investigates the observer-based H(infinity) control problem of networked nonlinear systems with global Lipschitz nonlinearities and random communication packet losses. The random packet loss is modelled as a Bernoulli distributed white sequence with a known conditional probability distribution. In the presence of random packet losses, sufficient conditions for the existence of an observer-based feedback controller are derived, such that the closed-loop networked nonlinear system is exponentially stable in the mean-square sense, and a prescribed H(infinity) disturbance-rejection-attenuation performance is also achieved. Then a linear matrix inequality (LMI) approach for designing such an observer-based H(infinity) controller is presented. Finally, a simulation example is used to demonstrate the effectiveness of the proposed method.

  3. Adaptive control of the packet transmission period with solar energy harvesting prediction in wireless sensor networks.

    PubMed

    Kwon, Kideok; Yang, Jihoon; Yoo, Younghwan

    2015-04-24

    A number of research works has studied packet scheduling policies in energy scavenging wireless sensor networks, based on the predicted amount of harvested energy. Most of them aim to achieve energy neutrality, which means that an embedded system can operate perpetually while meeting application requirements. Unlike other renewable energy sources, solar energy has the feature of distinct periodicity in the amount of harvested energy over a day. Using this feature, this paper proposes a packet transmission control policy that can enhance the network performance while keeping sensor nodes alive. Furthermore, this paper suggests a novel solar energy prediction method that exploits the relation between cloudiness and solar radiation. The experimental results and analyses show that the proposed packet transmission policy outperforms others in terms of the deadline miss rate and data throughput. Furthermore, the proposed solar energy prediction method can predict more accurately than others by 6.92%.

  4. Moving the boundary between wavelength resources in optical packet and circuit integrated ring network.

    PubMed

    Furukawa, Hideaki; Miyazawa, Takaya; Wada, Naoya; Harai, Hiroaki

    2014-01-13

    Optical packet and circuit integrated (OPCI) networks provide both optical packet switching (OPS) and optical circuit switching (OCS) links on the same physical infrastructure using a wavelength multiplexing technique in order to deal with best-effort services and quality-guaranteed services. To immediately respond to changes in user demand for OPS and OCS links, OPCI networks should dynamically adjust the amount of wavelength resources for each link. We propose a resource-adjustable hybrid optical packet/circuit switch and transponder. We also verify that distributed control of resource adjustments can be applied to the OPCI ring network testbed we developed. In cooperation with the resource adjustment mechanism and the hybrid switch and transponder, we demonstrate that automatically allocating a shared resource and moving the wavelength resource boundary between OPS and OCS links can be successfully executed, depending on the number of optical paths in use.

  5. 40-Gbit/s photonic random access memory for photonic packet-switched networks

    NASA Astrophysics Data System (ADS)

    Takahashi, Ryo; Nakahara, Tatsushi; Takahata, Kiyoto; Takenouchi, Hirokazu; Yasui, Takako; Kondo, Naoto; Suzuki, Hiroyuki

    2004-06-01

    We present a photonic random access memory (RAM) that can write and read high-speed asynchronous burst optical packets freely by specifying addresses. The photonic RAM consists of an optical clock-pulse generator, an all-optical serial-to-parallel converter, a photonic parallel-to-serial converter, all developed by us, and a CMOS RAM as a storage medium. Unlike conventional optical buffers, which merely function as optical delay lines, the photonic RAM provides various advantages, such as compactness, large capacity, long-term storage, and random access at an arbitrary timing for ultrafast asynchronous burst optical packets. We experimentally confirm its basic operation for 40-Gbit/s 16-bit optical packets.

  6. Covariant asymmetric wave packet for a field-theoretical description of neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Naumov, Vadim A.; Shkirmanov, Dmitry S.

    2015-06-01

    We consider a class of models for the relativistic covariant wave packets (WPs) which can be used as asymptotically free in and out states in the quantum field theoretical formalisms for description of the neutrino flavor oscillation phenomenon. We demonstrate that the new “asymmetric” wave packet (AWP) is an appropriate alternative to the more conventional “symmetric” WPs, like the so-called relativistic Gaussian packet (RGP) widely used in the quantum field theory (QFT)-based approaches to neutrino oscillations. We show that RGP is not a particular case of AWP, although many properties of these models are almost identical in the quasistable regime. We discuss some features of AWP distinguishing it from RGP.

  7. All-optical 2-bit header recognition and packet switching using polarization bistable VCSELs.

    PubMed

    Hayashi, Daisuke; Nakao, Kazuya; Katayama, Takeo; Kawaguchi, Hitoshi

    2015-04-01

    We propose and evaluate an all-optical 2-bit header recognition and packet switching method using two 1.55-µm polarization bistable vertical-cavity surface-emitting lasers (VCSELs) and three optical switches. Polarization bistable VCSELs acted as flip-flop devices by using AND-gate operations of the header and set pulses, together with the reset pulses. Optical packets including 40-Gb/s non-return-to-zero pseudo-random bit-sequence payloads were successfully sent to one of four ports according to the state of two bits in the headers with a 4-bit 500-Mb/s return-to-zero format. The input pulse powers were 17.2 to 31.8 dB lower than the VCSEL output power. We also examined an extension of this method to multi-bit header recognition and packet switching.

  8. Preserving bandwidth using a lazy packet discard policy in ATM networks

    NASA Astrophysics Data System (ADS)

    Bestavros, Azer; Kim, Gitae

    1999-08-01

    In this paper, we introduce Lazy Packet Discard (LPD), an AAL-level enhancement that improves effective throughput, reduces response time, and minimizes wasted bandwidth for TCP/IP over ATM. In contrast to the SCD and EPD policies, LPD delays as much as possible the removal from the network of cells belonging to a partially communicated packet. LPD preserves network bandwidth by keeping such cells alive and by ensuring that additional cells, obtained through Reed- Solomon block coding at the sender's AAL, are eventually transmitted to salvage the packet in question. We outline the implementation of LPD and show the performance advantage of TCP/LPD, compared to plain TCP and TCP/EPD through analysis and simulations.

  9. Energy-saving scheme based on downstream packet scheduling in ethernet passive optical networks

    NASA Astrophysics Data System (ADS)

    Zhang, Lincong; Liu, Yejun; Guo, Lei; Gong, Xiaoxue

    2013-03-01

    With increasing network sizes, the energy consumption of Passive Optical Networks (PONs) has grown significantly. Therefore, it is important to design effective energy-saving schemes in PONs. Generally, energy-saving schemes have focused on sleeping the low-loaded Optical Network Units (ONUs), which tends to bring large packet delays. Further, the traditional ONU sleep modes are not capable of sleeping the transmitter and receiver independently, though they are not required to transmit or receive packets. Clearly, this approach contributes to wasted energy. Thus, in this paper, we propose an Energy-Saving scheme that is based on downstream Packet Scheduling (ESPS) in Ethernet PON (EPON). First, we design both an algorithm and a rule for downstream packet scheduling at the inter- and intra-ONU levels, respectively, to reduce the downstream packet delay. After that, we propose a hybrid sleep mode that contains not only ONU deep sleep mode but also independent sleep modes for the transmitter and the receiver. This ensures that the energy consumed by the ONUs is minimal. To realize the hybrid sleep mode, a modified GATE control message is designed that involves 10 time points for sleep processes. In ESPS, the 10 time points are calculated according to the allocated bandwidths in both the upstream and the downstream. The simulation results show that ESPS outperforms traditional Upstream Centric Scheduling (UCS) scheme in terms of energy consumption and the average delay for both real-time and non-real-time packets downstream. The simulation results also show that the average energy consumption of each ONU in larger-sized networks is less than that in smaller-sized networks; hence, our ESPS is better suited for larger-sized networks.

  10. Reconstruction and control of a time-dependent two-electron wave packet

    NASA Astrophysics Data System (ADS)

    Ott, Christian; Kaldun, Andreas; Argenti, Luca; Raith, Philipp; Meyer, Kristina; Laux, Martin; Zhang, Yizhu; Blättermann, Alexander; Hagstotz, Steffen; Ding, Thomas; Heck, Robert; Madroñero, Javier; Martín, Fernando; Pfeifer, Thomas

    2014-12-01

    The concerted motion of two or more bound electrons governs atomic and molecular non-equilibrium processes including chemical reactions, and hence there is much interest in developing a detailed understanding of such electron dynamics in the quantum regime. However, there is no exact solution for the quantum three-body problem, and as a result even the minimal system of two active electrons and a nucleus is analytically intractable. This makes experimental measurements of the dynamics of two bound and correlated electrons, as found in the helium atom, an attractive prospect. However, although the motion of single active electrons and holes has been observed with attosecond time resolution, comparable experiments on two-electron motion have so far remained out of reach. Here we show that a correlated two-electron wave packet can be reconstructed from a 1.2-femtosecond quantum beat among low-lying doubly excited states in helium. The beat appears in attosecond transient-absorption spectra measured with unprecedentedly high spectral resolution and in the presence of an intensity-tunable visible laser field. We tune the coupling between the two low-lying quantum states by adjusting the visible laser intensity, and use the Fano resonance as a phase-sensitive quantum interferometer to achieve coherent control of the two correlated electrons. Given the excellent agreement with large-scale quantum-mechanical calculations for the helium atom, we anticipate that multidimensional spectroscopy experiments of the type we report here will provide benchmark data for testing fundamental few-body quantum dynamics theory in more complex systems. They might also provide a route to the site-specific measurement and control of metastable electronic transition states that are at the heart of fundamental chemical reactions.

  11. Multi-level basis selection of wavelet packet decomposition tree for heart sound classification.

    PubMed

    Safara, Fatemeh; Doraisamy, Shyamala; Azman, Azreen; Jantan, Azrul; Abdullah Ramaiah, Asri Ranga

    2013-10-01

    Wavelet packet transform decomposes a signal into a set of orthonormal bases (nodes) and provides opportunities to select an appropriate set of these bases for feature extraction. In this paper, multi-level basis selection (MLBS) is proposed to preserve the most informative bases of a wavelet packet decomposition tree through removing less informative bases by applying three exclusion criteria: frequency range, noise frequency, and energy threshold. MLBS achieved an accuracy of 97.56% for classifying normal heart sound, aortic stenosis, mitral regurgitation, and aortic regurgitation. MLBS is a promising basis selection to be suggested for signals with a small range of frequencies.

  12. Experimental observation of simultaneous wave and particle behavior in a narrowband single-photon wave packet

    NASA Astrophysics Data System (ADS)

    Yan, Hui; Liao, Kaiyu; Deng, Zhitao; He, Junyu; Xue, Zheng-Yuan; Zhang, Zhi-Ming; Zhu, Shi-Liang

    2015-04-01

    Light's wave-particle duality is at the heart of quantum mechanics and can be well illustrated by Wheeler's delayed-choice experiment: The choice of inserting or removing the second classical (quantum) beam splitter in a Mach-Zehnder interferometer determines the classical (quantum) wave-particle behavior of a photon. In this paper, we report our experiment on directly observing simultaneous wave and particle behavior in a narrowband single-photon wave packet by classically inserting or removing the second beam splitter when part of the wave packet passes through it. Our experiment demonstrates that the produced wave-particle state can be utilized in encoding quantum information.

  13. Generation of Quasiclassical Bohr-Like Wave Packets Using Half-Cycle Pulses

    SciTech Connect

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

    2008-08-01

    We demonstrate the experimental realization of Bohr-like atoms by applying a pulsed unidirectional field, termed a half-cycle pulse (HCP), to atoms in quasi-two-dimensional near-circular states. This leads to creation of localized wave packets that travel in near-circular orbits and mimic the dynamics of an electron in the original Bohr model of the hydrogen atom. This motion can be followed for several orbital periods before the localization of the wave packet is lost due to dephasing. We show, however, that localization can be recovered by application of further HCPs.

  14. Time-dependent treatment of scattering. II - Novel integral equation approach to quantum wave packets

    NASA Technical Reports Server (NTRS)

    Sharafeddin, Omar A.; Judson, Richard S.; Kouri, Donald J.; Hoffman, David K.

    1990-01-01

    The novel wave-packet propagation scheme presented is based on the time-dependent form of the Lippman-Schwinger integral equation and does not require extensive matrix inversions, thereby facilitating application to systems in which some degrees of freedom express the potential in a basis expansion. The matrix to be inverted is a function of the kinetic energy operator, and is accordingly diagonal in a Bessel function basis set. Transition amplitudes for various orbital angular momentum quantum numbers are obtainable via either Fourier transform of the amplitude density from the time to the energy domain, or the direct analysis of the scattered wave packet.

  15. Motion of an Atomic Wave Packet in a Standing-Wave Cavity Field

    NASA Astrophysics Data System (ADS)

    Chough, Young-Tak

    2007-11-01

    We present an in-depth study on the behavior of an atomic wave packet which is placed in a standing wave cavity prepared in various states of light. We extract a simple classical oscillator model out of the dynamics of the quantum system. We quantitatively resolve the states of the spatially reorganized wave packet by the dressed state spatial probability distribution functions we developed. We also report a novel type of the “quantum collapse and revival” behavior of the Rabi nutation which is originated from the effect of the quantized atomic center-of-mass motion on the atomic internal motion.

  16. Performance evaluation of a burst-mode EDFA in an optical packet and circuit integrated network.

    PubMed

    Shiraiwa, Masaki; Awaji, Yoshinari; Furukawa, Hideaki; Shinada, Satoshi; Puttnam, Benjamin J; Wada, Naoya

    2013-12-30

    We experimentally investigate the performance of burst-mode EDFA in an optical packet and circuit integrated system. In such networks, packets and light paths can be dynamically assigned to the same fibers, resulting in gain transients in EDFAs throughout the network that can limit network performance. Here, we compare the performance of a 'burst-mode' EDFA (BM-EDFA), employing transient suppression techniques and optical feedback, with conventional EDFAs, and those using automatic gain control and previous BM-EDFA implementations. We first measure gain transients and other impairments in a simplified set-up before making frame error-rate measurements in a network demonstration.

  17. Gaussian wave packet states of scalar fields in a universe of de Sitter

    SciTech Connect

    Lopes, C. E. F.; Pedrosa, I. A.; Furtado, C.; Carvalho de M, A. M.

    2009-08-15

    In this work, we study quantum effects of a massive scalar field in the de Sitter spacetime. We reduce the problem to that of a time-dependent harmonic oscillator and use exact linear invariants and the dynamic invariant method to derive the corresponding Schroedinger states in terms of solutions of a second order ordinary differential equation. Afterwards, we construct Gaussian wave packet states and calculate the quantum dispersions as well as the quantum correlations for each mode of the quantized scalar field. It is further shown that the center of the Gaussian wave packet remains trapped in the origin.

  18. Mesoscopic superposition and sub-Planck-scale structure in molecular wave packets

    SciTech Connect

    Ghosh, Suranjana; Banerji, J.; Panigrahi, P. K.; Chiruvelli, Aravind

    2006-01-15

    We demonstrate the possibility of realizing sub-Planck-scale structures in the mesoscopic superposition of molecular wave packets involving vibrational levels. The time evolution of the wave packet, taken here as the SU(2) coherent state of the Morse potential describing hydrogen iodide molecules, produces macroscopic-quantum-superposition-like states, responsible for the above phenomenon. We investigate the phase-space dynamics of the coherent state through the Wigner function approach and identify the interference phenomena behind the sub-Planck-scale structures. The optimal parameter ranges are specified for observing these features.

  19. The experiment of CCSDS packet telemetry using a highly elliptical orbit satellite 'Hiten'

    NASA Astrophysics Data System (ADS)

    Takano, Tadashi; Yamada, Takahiro; Shuto, Koshiro; Tanaka, Toshiyuki; Moyd, Katherine I.

    This paper describes the outline of the telemetry scheme proposed by the Consultative Committee of Space Data Systems (CCSDS), and the on-orbit experiment which was carried out to show the applicability of the CCSDS packet telemetry scheme using the Japan's satellite Hiten in a highly elliptical orbit. The telemetry data which are generated by the instruments are packetized in Hiten and reformed to the original data in earth stations successfully. The experimental results showed that the standardized scheme is helpful in allowing for tracking cross support between organizations, and the concatenated code is quite effective to transmit data in a low C/N condition.

  20. A Gaussian wave packet phase-space representation of quantum canonical statistics

    SciTech Connect

    Coughtrie, David J.; Tew, David P.

    2015-07-28

    We present a mapping of quantum canonical statistical averages onto a phase-space average over thawed Gaussian wave-packet (GWP) parameters, which is exact for harmonic systems at all temperatures. The mapping invokes an effective potential surface, experienced by the wave packets, and a temperature-dependent phase-space integrand, to correctly transition from the GWP average at low temperature to classical statistics at high temperature. Numerical tests on weakly and strongly anharmonic model systems demonstrate that thermal averages of the system energy and geometric properties are accurate to within 1% of the exact quantum values at all temperatures.

  1. Spectral bandwidth scaling laws and reconstruction of THz wave packets generated from two-color laser plasma filaments

    NASA Astrophysics Data System (ADS)

    Koulouklidis, A. D.; Fedorov, V. Yu.; Tzortzakis, S.

    2016-03-01

    We find the spectral bandwidth scaling laws of the THz wave packets, produced from two-color laser filaments, as a function of the input laser-pulse duration and demonstrate how one can fully recover the original broadband THz wave packets even using narrow-band detection techniques such as the widespread electro-optic sampling.

  2. Three Packets with Which to Evaluate Teacher In-Service Workshops via Participant Evaluation and via Observer Evaluation.

    ERIC Educational Resources Information Center

    Alvir, Howard P.

    Three evaluation packets which can serve as guidelines for evaluation models are illustrated in this document. These packages were designed originally for occupational educators, but editing can make these packets and evaluation forms applicable to any area in which secondary and post-secondary teachers attend an inservice workshop or training…

  3. The Texas Real Estate License Act. Teachers Instructional Packet (TIP), No. 1, Fall 1984. Revised Fall 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 content and complexities of the Real Estate License Act of Texas. The packet has three parts. The first two parts provide an instructor's evaluation form and the instructor's guide to the law,…

  4. 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

  5. On-board B-ISDN fast packet switching architectures. Phase 2: Development. Proof-of-concept architecture definition report

    NASA Technical Reports Server (NTRS)

    Shyy, Dong-Jye; Redman, Wayne

    1993-01-01

    For the next-generation packet switched communications satellite system with onboard processing and spot-beam operation, a reliable onboard fast packet switch is essential to route packets from different uplink beams to different downlink beams. The rapid emergence of point-to-point services such as video distribution, and the large demand for video conference, distributed data processing, and network management makes the multicast function essential to a fast packet switch (FPS). The satellite's inherent broadcast features gives the satellite network an advantage over the terrestrial network in providing multicast services. This report evaluates alternate multicast FPS architectures for onboard baseband switching applications and selects a candidate for subsequent breadboard development. Architecture evaluation and selection will be based on the study performed in phase 1, 'Onboard B-ISDN Fast Packet Switching Architectures', and other switch architectures which have become commercially available as large scale integration (LSI) devices.

  6. The Assessment of Print Materials. Individualized Inservice Packet Number I. Teaching Teen Reading Series.

    ERIC Educational Resources Information Center

    Ohio State Dept. of Education, Columbus.

    This individualized inservice packet provides teachers with guidelines for the meaningful selection and assessment of print materials, so that they may locate and utilize the appropriate reading content for individual students. It is one of a nine-part series of booklets--Teaching Teen Reading--in self-instructional format, intended as a practical…

  7. 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.

  8. Job Discrimination. A Curriculum Packet about Immigration-Related Job Discrimination.

    ERIC Educational Resources Information Center

    Nash, Andrea; Wright, Peggy

    A curriculum packet is presented that is designed to give English-as-a-Second-Language (ESL) teachers the information and tools they need to help students address the issue of job discrimination, especially discrimination based on citizenship status or national origin that may result from the employer verification requirement of the Immigration…

  9. Are the Ideas of Learning Kejar Packet A of Indonesia Still Valid?

    ERIC Educational Resources Information Center

    Napitupulu, Washington P.

    Introduced in Indonesia in 1977, the Learning Kejar Packet A (LKPA) is an educational program for low-literate people and primary school dropouts. The 20-year-old program is still flourishing, but are its ideas still valid and what are the secrets of its longevity? The first reason probably lies in the contents and design of the learning materials…

  10. The Gorgeous Mosaic: A Work of Art by the Schoolchildren of the World. Teacher's Packet.

    ERIC Educational Resources Information Center

    Gura, Mark

    This document is a packet of information for art teachers about the Gorgeous Mosaic, a project being carried out by the classroom art teachers of the world in which students individually draw portraits of the many different types of youngsters there are in their world on small cardboard tiles. The completed tiles are mounted on panels for…

  11. Space-time correlations in inflationary spectra: A wave-packet analysis

    SciTech Connect

    Campo, David; Parentani, Renaud

    2004-11-15

    The inflationary mechanism of mode amplification predicts that the state of each mode with a given wave vector is correlated to that of its partner mode with the opposite vector. This implies nonlocal correlations which leave their imprint on temperature anisotropies in the cosmic microwave background. Their spatial properties are best revealed by using local wave packets. This analysis shows that all density fluctuations giving rise to the large scale structures originate in pairs which are born near the reheating. In fact each local density fluctuation is paired with an oppositely moving partner with opposite amplitude. To obtain these results we first apply a 'wave packet transformation' with respect to one argument of the two-point correlation function. A finer understanding of the correlations is then reached by making use of coherent states. A knowledge of the velocity field is required to extract the contribution of a single pair of wave packets. Otherwise, there is a two-folded degeneracy which gives three aligned wave packets arising from two pairs. The applicability of these methods to observational data is briefly discussed.

  12. Anxiety, Fears, Phobias, and Related Problems: Intervention and Resources for School Aged Youth. An Introductory Packet.

    ERIC Educational Resources Information Center

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

    This introductory packet provides an introduction to anxiety problems, framing the discussion within the classification scheme developed by the American Pediatric Association. The variations in degree of problem are discussed with respect to interventions that range from environmental accommodations to behavioral strategies to medication. The…

  13. Affect and Mood Problems Related to School Aged Youth. An Introductory Packet.

    ERIC Educational Resources Information Center

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

    This introductory packet provides an introduction to affect and mood problems, framing the discussion within the classification scheme developed by the American Pediatric Association. Included is information on the symptoms and severity of a variety of affect and mood problems, as well as information on interventions ranging from environmental…

  14. Project Trade Related Reading Packets for Disabled Readers. Final Report 1984-85.

    ERIC Educational Resources Information Center

    Davis, Beverly; Woodruff, Nancy S.

    A comprehensive, shop-related curriculum was developed for special needs students who are severely disabled readers. The basic approach of the curriculum was to provide individualized diagnostic-prescriptive materials that correlate basic reading skills and the required vocational and technical concepts. Trade-related packets were written for…

  15. "The Taming of the Shrew." 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 "The Taming of the Shrew." Materials include: staging suggestions for scenery, props, lighting, and…

  16. Manager's Informational Packet. Project VISIONS. National Workplace Skills Project. January 1, 1995-December 31, 1998.

    ERIC Educational Resources Information Center

    Orangeburg-Calhoun Technical Coll., Orangeburg, SC.

    This packet of information was developed to be distributed as an informational referral tool for a workplace literacy project following an oral presentation by project staff. It includes the following sections: a managers' checklist; questions managers ask; manager's survey; information about workplace literacy; characteristics of work-based…

  17. Simmons Insurance Agency. A Clerk-Typist Position Simulation. Student Packet II. Office Occupations.

    ERIC Educational Resources Information Center

    Georgia State Univ., Atlanta.

    This is the second of five student packets forming part of a position simulation developed for use in an office applications laboratory at the postsecondary level. The purpose of the simulation is to give the student an opportunity to become familiar with the tasks and duties performed by a clerk-typist working for an independent insurance agency.…

  18. Packet speech transmission on ATM networks using a variable rate embedded ADPCM coding scheme

    NASA Astrophysics Data System (ADS)

    Kondo, Kazuhiro; Ohno, Masashi

    1994-02-01

    We propose a packet speech coding scheme to vary the code bits of an embedded ADPCM coder between 6 bits per sample, for high prediction gain speech blocks, to 2 bits for blocks representing silence. Subjective quality of 3.2 MOS on a scale of 1 to 5 at an enhancement-bit loss rate of 30% was obtained in our tests.

  19. Burst-mode-operated, sub-nanosecond fiber MOPA system incorporating direct seed-packet shaping.

    PubMed

    Chen, Tao; Liu, Hao; Kong, Wei; Shu, Rong

    2016-09-01

    We report a novel burst-mode-operated sub-nanosecond fiber Master Oscillator, Power Amplifier (MOPA) system incorporating direct seed-packet shaping without external modulators. A fast digital-to-analog converter with 1 Gsps sampling rate and 16 bit resolution was developed to control the pulse amplitudes and sequences of a distributed feedback semiconductor seed laser to realize packet-shaped burst mode operation. Optical pulses with durations as short as 700 ps and peak power as high as 1 W can be generated from the seed by applying proper reverse voltages after positive electrical pulses to the laser driver to cancel the residual charges at its gate electrode. The average power of the laser can be amplified to nearly 40 W with FWHM spectral linewidth of ~0.12 nm after three stages of polarization maintaining fiber amplifiers. Different packet shapes including ramp-off, Gaussian, square and double rectangle can be produced from the fiber MOPA by finely pre-shaping the seed pulse bursts. It is believed that such a laser has provided a cost-effective solution to the generation of pulse bursts with arbitrary packet shapes for different practical applications including material micromachining and nonlinear frequency conversion. PMID:27607699

  20. Ecologia: Spanish Ecology Packet Resource Units and Materials for Intermediate and Advanced Spanish Classes.

    ERIC Educational Resources Information Center

    Bell, Mozelle Sawyer; Arribas, E. Jaime

    This Spanish ecology packet contains resource units and materials for intermediate and advanced Spanish classes. It is designed to be used for individual and small-group instruction in the senior high school to supplement the Spanish language curriculum. Included are articles, pictures, and cartoons from Spanish-language newspapers and magazines…

  1. Motion of an Electron Wave Packet in a Uniform Electric Field

    ERIC Educational Resources Information Center

    Churchill, John N.

    1978-01-01

    Energy eigenstates are superimposed in order to form a wave packet for an electron propagating in one dimension under the influence of a uniform, time-dependent electric field. A graphical method is presented by which one can obtain both the position and shape of the envelope. (BB)

  2. A Teacher's Ready-to-Use Packet of General Business Subjects Crossword Puzzles.

    ERIC Educational Resources Information Center

    Yacyk, Peter

    Eleven crossword puzzles, designed to give the student practice with the correct spelling and usage of those words needed to indicate his mastery of the concepts and understandings taught in business courses, are contained, with answer keys, in a teacher's packet. Any puzzle can be reproduced by ditto or by transparency for classroom use. There is…

  3. Characteristics of the High Performance Real Estate Salesperson. Teachers Instructional Packet, TIP No. 12, Spring 1987.

    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 characteristics of Texas real estate salespersons based on a 1983 state survey. First, questions for class discussion are presented, followed by a summary presentation on the survey findings,…

  4. Development of an Educational Packet for Persons with Life-Threatening Food Allergies

    ERIC Educational Resources Information Center

    Olson, Bradley F.; Teuber, Suzanne; Bruhn, Christine M.

    2009-01-01

    Previous studies have shown that those with severe food allergies have significant gaps in knowledge about their disease and how to prevent recurrences. The purpose of this study was to address these deficiencies by creating and testing an educational packet, "Coping with Food Allergies." Participants included 46 of 58 adults with documented…

  5. The Paradox of Giftedness and Autism: Packet of Information for Families

    ERIC Educational Resources Information Center

    Nicpon, Megan Foley; Assouline, Susan G.; Colangelo, Nicholas; O'Brien, Matthew

    2008-01-01

    This "Packet of Information for Families" (PIF) was developed for parents whose children are identified as both gifted/ talented and on the autism spectrum, or twice-exceptional. Parents of twice-exceptional children often search for appropriate and challenging enrichment programs for their child, but the dearth of information available about how…

  6. Underwater Acoustic Communications: Relationship Between Data Packet Size, Throughput, Ber, and Distance

    NASA Astrophysics Data System (ADS)

    Jung, Low Tang; Abdullah, Azween B.

    2011-06-01

    The authors of this paper embarked on a research to find an effective mechanism or algorithm to determine the optimal data packet size for efficient underwater acoustic (UWA) data transmission. In the course of the research the authors have identified some of the UWA channel parameters that play an important role in determining the suitable data packet size for efficient data transfer. These include the distance between a source and a sink, bit error rate, type of protocol, energy per useful bit, and the throughput. In this paper the authors present the findings on the relationship between data packet size, the throughput, the bit error rate (BER), and the distance between a source-sink pair by keeping the type of protocol and the energy per useful bit parameters constant. These findings represent the preliminary contribution in parts to the final induction of the algorithm for data packet size optimization. The results obtained are based on simulation using the MIRACLE (Multi-InteRfAce Cross-Layer Extension library) package running on standard ns2 network simulator.

  7. Simmons Insurance Agency. A Clerk-Typist Position Simulation. Student Packet III. Office Occupations.

    ERIC Educational Resources Information Center

    Georgia State Univ., Atlanta.

    This is the third of five student packets forming part of a position simulation developed for use in an office applications laboratory at the postsecondary level. The purpose of the simulation is to give the student an opportunity to become familiar with the tasks and duties performed by a clerk-typist working for an independent insurance agency.…

  8. 78 FR 10263 - Proposed Collection; Comment Request for ADA Accommodations Request Packet

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-02-13

    ... Internal Revenue Service Proposed Collection; Comment Request for ADA Accommodations Request Packet AGENCY... U.S.C. 3506(c)(2)(A)). Currently, the IRS is soliciting comments concerning the ADA Accommodations... through the Internet, at Martha.R.Brinson @irs.gov. SUPPLEMENTARY INFORMATION: Title: ADA...

  9. SCDC Spanish Curricula Units. Science/Math Strand, Unit 4, Grade 2, Supplements & Ditto Packet.

    ERIC Educational Resources Information Center

    Spanish Curricula Development Center, Miami Beach, FL.

    Designed for use with unit four of the science/math strand for second graders, the supplement and ditto packet contain visuals, worksheets, and instructional aids referred to in the teacher's guide corresponding to this unit. The brief introductions to kits 13-16 are written in both English and Spanish; all classroom materials for students are in…

  10. Pressure fluctuations beneath turbulent spots and instability wave packets in a hypersonic boundary layer.

    SciTech Connect

    Beresh, Steven Jay; Casper, Katya M.; Schneider, Steven P.

    2010-12-01

    The development of turbulent spots in a hypersonic boundary layer was studied on the nozzle wall of the Boeing/AFOSR Mach-6 Quiet Tunnel. Under quiet flow conditions, the nozzle wall boundary layer remains laminar and grows very thick over the long nozzle length. This allows the development of large turbulent spots that can be readily measured with pressure transducers. Measurements of naturally occurring wave packets and developing turbulent spots were made. The peak frequencies of these natural wave packets were in agreement with second-mode computations. For a controlled study, the breakdown of disturbances created by spark and glow perturbations were studied at similar freestream conditions. The spark perturbations were the most effective at creating large wave packets that broke down into turbulent spots. The flow disturbances created by the controlled perturbations were analyzed to obtain amplitude criteria for nonlinearity and breakdown as well as the convection velocities of the turbulent spots. Disturbances first grew into linear instability waves and then quickly became nonlinear. Throughout the nonlinear growth of the wave packets, large harmonics are visible in the power spectra. As breakdown begins, the peak amplitudes of the instability waves and harmonics decrease into the rising broad-band frequencies. Instability waves are still visible on either side of the growing turbulent spots during this breakdown process.

  11. Simmons Insurance Agency. A Clerk-Typist Position Simulation. Student Packet IV. Office Occupations.

    ERIC Educational Resources Information Center

    Georgia State Univ., Atlanta.

    This is the fourth of five student packets forming part of a position simulation developed for use in an office applications laboratory at the postsecondary level. The purpose of the simulation is to give the student an opportunity to become familiar with the tasks and duties performed by a clerk-typist working for an independent insurance agency.…

  12. Is Disgust the Driver behind the Selection of Images for UK Tobacco Packets?

    ERIC Educational Resources Information Center

    Humphris, Gerry; Williams, Brian

    2014-01-01

    Objective: The use of pictorial warning labels on tobacco packets has gained almost universal international acceptance. In a public consultation exercise in 2006, the Department of Health in England, through a web-based answering system, asked people's preferences of 42 images, asking which images might be effective to encourage tobacco…

  13. [A Packet of Information on the Background of the AFT-NEA Merger Break.

    ERIC Educational Resources Information Center

    American Federation of Teachers, Washington, DC.

    This document contains informational materials about the breakdown in merger talks between the American Federation of Teachers (AFT) and the National Education Association (NEA). Included in the packet are (a) the AFT statement on the breakup of unity talks; (b) transcripts of two news conferences by David Selden, president of the AFT, on the…

  14. The Paradox of Giftedness and Autism: Packet of Information for Professionals (PIP)--Revised (2008)

    ERIC Educational Resources Information Center

    Assouline, Susan G.; Nicpon, Megan Foley; Colangelo, Nicholas; O'Brien, Matthew

    2008-01-01

    This "Packet of Information for Professionals" (PIP) was developed for professionals who work with gifted and talented students who have an autism spectrum disorder (ASD). The purpose of PIP is to offer recommendations that will lead to a positive experience for twice-exceptional students who participate in specialized programs for gifted/talented…

  15. Map Resource Packet: Course Models for the History-Social Science Framework, Grade Seven.

    ERIC Educational Resources Information Center

    California State Dept. of Education, Sacramento.

    This packet of maps is an auxiliary resource to the "World History and Geography: Medieval and Early Modern Times. Course Models for the History-Social Science Framework, Grade Seven." The set includes: outline, precipitation, and elevation maps; maps for locating key places; landform maps; and historical maps. The list of maps are grouped under…

  16. Wave-packet dynamics of noninteracting ultracold bosons in an amplitude-modulated parabolic optical lattice

    NASA Astrophysics Data System (ADS)

    Yamakoshi, Tomotake; Watanabe, Shinichi

    2015-06-01

    The recent Aarhus experiment [Phys. Rev. A 88, 023620 (2013), 10.1103/PhysRevA.88.023620] produced wave packets by applying amplitude modulation to a trapped Bose-Einstein condensate (BEC) of 87Rb using an optical lattice. The present paper renders a theoretical account of this experimental production of wave packets and their subsequent time evolution, focusing on a one-dimensional noninteracting bosonic system as a fundamental starting point for accurate quantum analysis. Since experimental manipulation requires efficient wave-packet creation, we introduce the "single-Q Rabi model" to give a simple and reliable description of the interband transition. As a natural extension, we demonstrate enhancement of the wave-packet production by the "two-step Rabi oscillation method" using either one or two frequencies. The subsequent time evolution is affected by the intertwining of Bragg reflection and the Landau-Zener transition at each band gap, which is analyzed with the aid of a semiclassical theory [Phys. Rev. Lett. 110, 085302 (2013), 10.1103/PhysRevLett.110.085302].

  17. Constitutional and Non-Constitutional Governments...Similarities and Differences throughout History. Resource Packet.

    ERIC Educational Resources Information Center

    Pallasch, Brian Thomas

    This civic education resource packet is designed to provide teachers, community leaders, and other civic educators with an understanding of the differences between constitutional and non-constitutional governments. Six papers discussing the topic are included: "The Differences bewteen Constitutional and Non-Constitutional Governments" (John…

  18. Simmons Insurance Agency. A Clerk-Typist Position Simulation. Student Packet I. Office Occupations.

    ERIC Educational Resources Information Center

    Georgia State Univ., Atlanta.

    This is the first of five student packets forming part of a position simulation developed for use in an office applications laboratory at the postsecondary level. The purpose of the simulation is to give the student an opportunity to become familiar with the tasks and duties performed by a clerk-typist working for an independent insurance agency.…

  19. Issues and Images: New Yorkers during the Thirties. A Teaching Packet of Historical Documents.

    ERIC Educational Resources Information Center

    New York State Education Dept., Albany. Cultural Education Center.

    Derived from an exhibit produced cooperatively by the New York State Archives and the New York State Museum for the Franklin D. Roosevelt Centennial, and designed to provide secondary students with first-hand exposure to New York during the Great Depression, this packet contains a teacher's guide and 22 facsimile documents, including historic…

  20. "Romeo and Juliet." 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 a Shakespeare play, this play packet contains ready-to-reproduce materials for the production of "Romeo and Juliet." Materials include: staging suggestions for scenery, props, lighting, and costumes; a…