WorldWideScience

Sample records for spaceborne memory organization

  1. Narratives and Memory in Organizations

    DEFF Research Database (Denmark)

    Rowlinson, Michael; Casey, Andrea; Hansen, Per H.

    2014-01-01

    Organizations remember through narratives and storytelling. The articles in this Special Issue explore the interface between organization studies, memory studies, and historiography. They focus on the practices for organizational remembering. Taken together, the articles explore the similarities...... and differences between ethnographic and historical methods for studying memory in organizations, which represents a contribution to the historic turn in organization studies....

  2. Emotional organization of autobiographical memory.

    Science.gov (United States)

    Schulkind, Matthew D; Woldorf, Gillian M

    2005-09-01

    The emotional organization of autobiographical memory was examined by determining whether emotional cues would influence autobiographical retrieval in younger and older adults. Unfamiliar musical cues that represented orthogonal combinations of positive and negative valence and high and low arousal were used. Whereas cue valence influenced the valence of the retrieved memories, cue arousal did not affect arousal ratings. However, high-arousal cues were associated with reduced response latencies. A significant bias to report positive memories was observed, especially for the older adults, but neither the distribution of memories across the life span nor response latencies varied across memories differing in valence or arousal. These data indicate that emotional information can serve as effective cues for autobiographical memories and that autobiographical memories are organized in terms of emotional valence but not emotional arousal. Thus, current theories of autobiographical memory must be expanded to include emotional valence as a primary dimension of organization.

  3. From silicon to organic nanoparticle memory devices.

    Science.gov (United States)

    Tsoukalas, D

    2009-10-28

    After introducing the operational principle of nanoparticle memory devices, their current status in silicon technology is briefly presented in this work. The discussion then focuses on hybrid technologies, where silicon and organic materials have been combined together in a nanoparticle memory device, and finally concludes with the recent development of organic nanoparticle memories. The review is focused on the nanoparticle memory concept as an extension of the current flash memory device. Organic nanoparticle memories are at a very early stage of research and have not yet found applications. When this happens, it is expected that they will not directly compete with mature silicon technology but will find their own areas of application.

  4. Organization and Memory in Adulthood.

    Science.gov (United States)

    Hultsch, David F.

    This paper discusses organizational processes and memory in general and organizational processes and adult age differences in memory in particular. The simplest analysis of memory is to divide the process into two parts: storage and retrieval. Studies show that the limitation of memory lies primarily in retrieval rather than storage. Organization…

  5. Organic ferroelectric opto-electronic memories

    NARCIS (Netherlands)

    Asadi, K.; Li, M.; Blom, P.W.M.; Kemerink, M.; Leeuw, D.M. de

    2011-01-01

    Memory is a prerequisite for many electronic devices. Organic non-volatile memory devices based on ferroelectricity are a promising approach towards the development of a low-cost memory technology based on a simple cross-bar array. In this review article we discuss the latest developments in this

  6. Organic Nonvolatile Memory Devices Based on Ferroelectricity

    NARCIS (Netherlands)

    Naber, Ronald C. G.; Asadi, Kamal; Blom, Paul W. M.; de Leeuw, Dago M.; de Boer, Bert

    2010-01-01

    A memory functionality is a prerequisite for many applications of electronic devices. Organic nonvolatile memory devices based on ferroelectricity are a promising approach toward the development of a low-cost memory technology. In this Review Article we discuss the latest developments in this area

  7. Organic nonvolatile memory devices based on ferroelectricity

    NARCIS (Netherlands)

    Naber, R.C.G.; Asadi, K.; Blom, P.W.M.; Leeuw, D.M. de; Boer, B. de

    2010-01-01

    A memory functionality is a prerequisite for many applications of electronic devices. Organic nonvolatile memory devices based on ferroelectricity are a promising approach toward the development of a low-cost memory technology. In this Review Article we discuss the latest developments in this area

  8. Neuroanatomic organization of sound memory in humans.

    Science.gov (United States)

    Kraut, Michael A; Pitcock, Jeffery A; Calhoun, Vince; Li, Juan; Freeman, Thomas; Hart, John

    2006-11-01

    The neural interface between sensory perception and memory is a central issue in neuroscience, particularly initial memory organization following perceptual analyses. We used functional magnetic resonance imaging to identify anatomic regions extracting initial auditory semantic memory information related to environmental sounds. Two distinct anatomic foci were detected in the right superior temporal gyrus when subjects identified sounds representing either animals or threatening items. Threatening animal stimuli elicited signal changes in both foci, suggesting a distributed neural representation. Our results demonstrate both category- and feature-specific responses to nonverbal sounds in early stages of extracting semantic memory information from these sounds. This organization allows for these category-feature detection nodes to extract early, semantic memory information for efficient processing of transient sound stimuli. Neural regions selective for threatening sounds are similar to those of nonhuman primates, demonstrating semantic memory organization for basic biological/survival primitives are present across species.

  9. Infants Hierarchically Organize Memory Representations

    Science.gov (United States)

    Rosenberg, Rebecca D.; Feigenson, Lisa

    2013-01-01

    Throughout development, working memory is subject to capacity limits that severely constrain short-term storage. However, adults can massively expand the total amount of remembered information by grouping items into "chunks". Although infants also have been shown to chunk objects in memory, little is known regarding the limits of this…

  10. Human Memory Organization for Computer Programs.

    Science.gov (United States)

    Norcio, A. F.; Kerst, Stephen M.

    1983-01-01

    Results of study investigating human memory organization in processing of computer programming languages indicate that algorithmic logic segments form a cognitive organizational structure in memory for programs. Statement indentation and internal program documentation did not enhance organizational process of recall of statements in five Fortran…

  11. Analysis of the Organization of Lexical Memory

    National Research Council Canada - National Science Library

    Miller, George

    1997-01-01

    The practical outcome of the project, Analysis of the Organization of Lexical Memory, is an electronic lexical database called WordNet that can be incorporated into computer systems for processing English text...

  12. Flexible NAND-Like Organic Ferroelectric Memory Array

    NARCIS (Netherlands)

    Kam, B.; Ke, T.H.; Chasin, A.; Tyagi, M.; Cristoferi, C.; Tempelaars, K.; Breemen, A.J.J.M. van; Myny, K.; Schols, S.; Genoe, J.; Gelinck, G.H.; Heremans, P.

    2014-01-01

    We present a memory array of organic ferroelectric field-effect transistors (OFeFETs) on flexible substrates. The OFeFETs are connected serially, similar to the NAND architecture of flash memory, which offers the highest memory density of transistor memories. We demonstrate a reliable addressing

  13. Spaceborne Photonics Institute

    Science.gov (United States)

    Venable, D. D.; Farrukh, U. O.; Han, K. S.; Hwang, I. H.; Jalufka, N. W.; Lowe, C. W.; Tabibi, B. M.; Lee, C. J.; Lyons, D.; Maclin, A.

    1994-01-01

    This report describes in chronological detail the development of the Spaceborne Photonics Institute as a sustained research effort at Hampton University in the area of optical physics. This provided the research expertise to initiate a PhD program in Physics. Research was carried out in the areas of: (1) modelling of spaceborne solid state laser systems; (2) amplified spontaneous emission in solar pumped iodine lasers; (3) closely simulated AM0 CW solar pumped iodine laser and repeatedly short pulsed iodine laser oscillator; (4) a materials spectroscopy and growth program; and (5) laser induced fluorescence and atomic and molecular spectroscopy.

  14. Special Operations Commemoration: Monuments, Memory & Memorialization Practices of Elite Organizations

    Science.gov (United States)

    2013-04-01

    historical narrative, feminist agendas that reject masculine war commemoration efforts, general anti-war sentiment, and, probably most significant of...Collective Memory of Political Events: Social Psychological Perspectives (Mahwah, N.J.: Lawrence Erlbaum Associates, 1997), 18. 37 Malgorzata...44 James W. Pennebaker, Collective Memory of Political Events: Social Psychological Perspectives (Mahwah, N.J.: Lawrence Erlbaum Associates, 1997

  15. The Effects of Motoric Action and Organization on Children's Memory.

    Science.gov (United States)

    Heindel, Patricia; Kose, Gary

    1990-01-01

    Two experiments examined preschool, first, and third grade students for the effects of motoric activities on memory performance. Findings for the first experiment revealed that, although organizational differences affected memory performance, the drawing of configurations enhanced the effect of unitary organization. In the second experiment,…

  16. The Organization of Reactivated Memory in Infancy.

    Science.gov (United States)

    Hayne, Harlene; Rovee-Collier, Carolyn

    1995-01-01

    Infants were trained to kick their feet into a crib mobile and tested two weeks later. Found that presentation of a moving, but not a stationary, mobile in a reminder treatment 24 hours before testing alleviated forgetting in the test and that, in the test, memory of the kicking activity was specific to the conditions of the original training. (BC)

  17. Temporal Organization of Sound Information in Auditory Memory

    Directory of Open Access Journals (Sweden)

    Kun Song

    2017-06-01

    Full Text Available Memory is a constructive and organizational process. Instead of being stored with all the fine details, external information is reorganized and structured at certain spatiotemporal scales. It is well acknowledged that time plays a central role in audition by segmenting sound inputs into temporal chunks of appropriate length. However, it remains largely unknown whether critical temporal structures exist to mediate sound representation in auditory memory. To address the issue, here we designed an auditory memory transferring study, by combining a previously developed unsupervised white noise memory paradigm with a reversed sound manipulation method. Specifically, we systematically measured the memory transferring from a random white noise sound to its locally temporal reversed version on various temporal scales in seven experiments. We demonstrate a U-shape memory-transferring pattern with the minimum value around temporal scale of 200 ms. Furthermore, neither auditory perceptual similarity nor physical similarity as a function of the manipulating temporal scale can account for the memory-transferring results. Our results suggest that sounds are not stored with all the fine spectrotemporal details but are organized and structured at discrete temporal chunks in long-term auditory memory representation.

  18. Temporal Organization of Sound Information in Auditory Memory.

    Science.gov (United States)

    Song, Kun; Luo, Huan

    2017-01-01

    Memory is a constructive and organizational process. Instead of being stored with all the fine details, external information is reorganized and structured at certain spatiotemporal scales. It is well acknowledged that time plays a central role in audition by segmenting sound inputs into temporal chunks of appropriate length. However, it remains largely unknown whether critical temporal structures exist to mediate sound representation in auditory memory. To address the issue, here we designed an auditory memory transferring study, by combining a previously developed unsupervised white noise memory paradigm with a reversed sound manipulation method. Specifically, we systematically measured the memory transferring from a random white noise sound to its locally temporal reversed version on various temporal scales in seven experiments. We demonstrate a U-shape memory-transferring pattern with the minimum value around temporal scale of 200 ms. Furthermore, neither auditory perceptual similarity nor physical similarity as a function of the manipulating temporal scale can account for the memory-transferring results. Our results suggest that sounds are not stored with all the fine spectrotemporal details but are organized and structured at discrete temporal chunks in long-term auditory memory representation.

  19. Spiers memorial lecture. Organic electronics: an organic materials perspective.

    Science.gov (United States)

    Wudl, Fred

    2014-01-01

    This Introductory Lecture is intended to provide a background to Faraday Discussion 174: "Organic Photonics and Electronics" and will consist of a chronological, subjective review of organic electronics. Starting with "ancient history" (1888) and history (1950-present), the article will take us to the present. The principal developments involved the processes of charge carrier generation and charge transport in molecular solids, starting with insulators (photoconductors) and moving to metals, to semiconductors and ending with the most popular semiconductor devices, such as organic light-emitting diodes (OLEDs), organic field effect transistors (OFETs) and organic photovoltaics (OPVs). The presentation will be from an organic chemistry/materials point of view.

  20. Light programmable organic transistor memory device based on hybrid dielectric

    Science.gov (United States)

    Ren, Xiaochen; Chan, Paddy K. L.

    2013-09-01

    We have fabricated the transistor memory devices based on SiO2 and polystyrene (PS) hybrid dielectric. The trap states densities with different semiconductors have been investigated and a maximum 160V memory window between programming and erasing is realized. For DNTT based transistor, the trapped electron density is limited by the number of mobile electrons in semiconductor. The charge transport mechanism is verified by light induced Vth shift effect. Furthermore, in order to meet the low operating power requirement of portable electronic devices, we fabricated the organic memory transistor based on AlOx/self-assembly monolayer (SAM)/PS hybrid dielectric, the effective capacitance of hybrid dielectric is 210 nF cm-2 and the transistor can reach saturation state at -3V gate bias. The memory window in transfer I-V curve is around 1V under +/-5V programming and erasing bias.

  1. Knowledge Loss: A Defensive Model In Nuclear Research Organization Memory

    International Nuclear Information System (INIS)

    Mohamad Safuan Bin Sulaiman; Muhd Noor Muhd Yunus

    2013-01-01

    Knowledge is an essential part of research based organization. It should be properly managed to ensure that any pitfalls of knowledge retention due to knowledge loss of both tacit and explicit is mitigated. Audit of the knowledge entities exist in the organization is important to identify the size of critical knowledge. It is very much related to how much know-what, know-how and know-why experts exist in the organization. This study conceptually proposed a defensive model for Nuclear Malaysia's organization memory and application of Knowledge Loss Risk Assessment (KLRA) as an important tool for critical knowledge identification. (author)

  2. A Vertical Organic Transistor Architecture for Fast Nonvolatile Memory.

    Science.gov (United States)

    She, Xiao-Jian; Gustafsson, David; Sirringhaus, Henning

    2017-02-01

    A new device architecture for fast organic transistor memory is developed, based on a vertical organic transistor configuration incorporating high-performance ambipolar conjugated polymers and unipolar small molecules as the transport layers, to achieve reliable and fast programming and erasing of the threshold voltage shift in less than 200 ns. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Organic nonvolatile memory devices with charge trapping multilayer graphene film

    International Nuclear Information System (INIS)

    Ji, Yongsung; Choe, Minhyeok; Cho, Byungjin; Song, Sunghoon; Yoon, Jongwon; Ko, Heung Cho; Lee, Takhee

    2012-01-01

    We fabricated an array-type organic nonvolatile memory device with multilayer graphene (MLG) film embedded in polyimide (PI) layers. The memory devices showed a high ON/OFF ratio (over 10 6 ) and a long retention time (over 10 4 s). The switching of the Al/PI/MLG/PI/Al memory devices was due to the presence of the MLG film inserted into the PI layers. The double-log current–voltage characteristics could be explained by the space-charge-limited current conduction based on a charge-trap model. A conductive atomic force microscopy found that the conduction paths in the low-resistance ON state were distributed in a highly localized area, which was associated with a carbon-rich filamentary switching mechanism. (paper)

  4. Modeling Sub-500MHz Space-Borne Radar Signal Propagation in Complex Media

    Data.gov (United States)

    National Aeronautics and Space Administration — Space-borne radar platforms are becoming increasingly prevalent in current and planned missions by NASA and partner organizations (e.g. the European Space Agency...

  5. Single-Walled Carbon-Nanotubes-Based Organic Memory Structures

    Directory of Open Access Journals (Sweden)

    Sundes Fakher

    2016-09-01

    Full Text Available The electrical behaviour of organic memory structures, based on single-walled carbon-nanotubes (SWCNTs, metal–insulator–semiconductor (MIS and thin film transistor (TFT structures, using poly(methyl methacrylate (PMMA as the gate dielectric, are reported. The drain and source electrodes were fabricated by evaporating 50 nm gold, and the gate electrode was made from 50 nm-evaporated aluminium on a clean glass substrate. Thin films of SWCNTs, embedded within the insulating layer, were used as the floating gate. SWCNTs-based memory devices exhibited clear hysteresis in their electrical characteristics (capacitance–voltage (C–V for MIS structures, as well as output and transfer characteristics for transistors. Both structures were shown to produce reliable and large memory windows by virtue of high capacity and reduced charge leakage. The hysteresis in the output and transfer characteristics, the shifts in the threshold voltage of the transfer characteristics, and the flat-band voltage shift in the MIS structures were attributed to the charging and discharging of the SWCNTs floating gate. Under an appropriate gate bias (1 s pulses, the floating gate is charged and discharged, resulting in significant threshold voltage shifts. Pulses as low as 1 V resulted in clear write and erase states.

  6. The organization of words and environmental sounds in memory.

    Science.gov (United States)

    Hendrickson, Kristi; Walenski, Matthew; Friend, Margaret; Love, Tracy

    2015-03-01

    In the present study we used event-related potentials to compare the organization of linguistic and meaningful nonlinguistic sounds in memory. We examined N400 amplitudes as adults viewed pictures presented with words or environmental sounds that matched the picture (Match), that shared semantic features with the expected match (Near Violation), and that shared relatively few semantic features with the expected match (Far Violation). Words demonstrated incremental N400 amplitudes based on featural similarity from 300-700ms, such that both Near and Far Violations exhibited significant N400 effects, however Far Violations exhibited greater N400 effects than Near Violations. For environmental sounds, Far Violations but not Near Violations elicited significant N400 effects, in both early (300-400ms) and late (500-700ms) time windows, though a graded pattern similar to that of words was seen in the mid-latency time window (400-500ms). These results indicate that the organization of words and environmental sounds in memory is differentially influenced by featural similarity, with a consistently fine-grained graded structure for words but not sounds. Published by Elsevier Ltd.

  7. Perceptual Organization and Operative Thought: A Study of Coherence in Memory.

    Science.gov (United States)

    Heindel, Patricia; Kose, Gary

    Examined in three studies were the influence of perceptual organization on children's memory and the relationship between operational thought and memory performance. In the first study, 72 children at 5, 7, and 9 years of age were given a series of Piagetian tasks and a memory task. Subjects were presented with 10 color-shape pairs depicted in…

  8. Early blindness alters the spatial organization of verbal working memory.

    Science.gov (United States)

    Bottini, Roberto; Mattioni, Stefania; Collignon, Olivier

    2016-10-01

    Several studies suggest that serial order in working memory (WM) is grounded on space. For a list of ordered items held in WM, items at the beginning of the list are associated with the left side of space and items at the end of the list with the right side. This suggests that maintaining items in verbal WM is performed in strong analogy to writing these items down on a physical whiteboard for later consultation (The Mental Whiteboard Hypothesis). What drives this spatial mapping of ordered series in WM remains poorly understood. In the present study we tested whether visual experience is instrumental in establishing the link between serial order in WM and spatial processing. We tested early blind (EB), late blind (LB) and sighted individuals in an auditory WM task. Replicating previous studies, left-key responses were faster for early items in the list whereas later items facilitated right-key responses in the sighted group. The same effect was observed in LB individuals. In contrast, EB participants did not show any association between space and serial position in WM. These results suggest that early visual experience plays a critical role in linking ordered items in WM and spatial representations. The analogical spatial structure of WM may depend in part on the actual experience of using spatially organized devices (e.g., notes, whiteboards) to offload WM. These practices are largely precluded to EB individuals, who instead rely to mnemonic devices that are less spatially organized (e.g., recordings, vocal notes). The way we habitually organize information in the external world may bias the way we organize information in our WM. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Pulse-modulated multilevel data storage in an organic ferroelectric resistive memory diode

    NARCIS (Netherlands)

    Lee, J.; Breemen, A.J.J.M. van; Khikhlovskyi, V.; Kemerink, M.; Janssen, R.A.J.; Gelinck, G.H.

    2016-01-01

    We demonstrate multilevel data storage in organic ferroelectric resistive memory diodes consisting of a phase-separated blend of P(VDF-TrFE) and a semiconducting polymer. The dynamic behaviour of the organic ferroelectric memory diode can be described in terms of the inhomogeneous field mechanism

  10. Short-term memory stores organized by information domain.

    Science.gov (United States)

    Noyce, Abigail L; Cestero, Nishmar; Shinn-Cunningham, Barbara G; Somers, David C

    2016-04-01

    Vision and audition have complementary affinities, with vision excelling in spatial resolution and audition excelling in temporal resolution. Here, we investigated the relationships among the visual and auditory modalities and spatial and temporal short-term memory (STM) using change detection tasks. We created short sequences of visual or auditory items, such that each item within a sequence arose at a unique spatial location at a unique time. On each trial, two successive sequences were presented; subjects attended to either space (the sequence of locations) or time (the sequence of inter item intervals) and reported whether the patterns of locations or intervals were identical. Each subject completed blocks of unimodal trials (both sequences presented in the same modality) and crossmodal trials (Sequence 1 visual, Sequence 2 auditory, or vice versa) for both spatial and temporal tasks. We found a strong interaction between modality and task: Spatial performance was best on unimodal visual trials, whereas temporal performance was best on unimodal auditory trials. The order of modalities on crossmodal trials also mattered, suggesting that perceptual fidelity at encoding is critical to STM. Critically, no cost was attributable to crossmodal comparison: In both tasks, performance on crossmodal trials was as good as or better than on the weaker unimodal trials. STM representations of space and time can guide change detection in either the visual or the auditory modality, suggesting that the temporal or spatial organization of STM may supersede sensory-specific organization.

  11. Short-term memory stores organized by information domain

    Science.gov (United States)

    Noyce, Abigail L.; Cestero, Nishmar; Shinn-Cunningham, Barbara G.; Somers, David C.

    2016-01-01

    Vision and audition have complementary affinities, with vision excelling in spatial resolution and audition excelling in temporal resolution. Here, we investigate the relationships among visual and auditory modalities and spatial and temporal short-term memory (STM) using change detection tasks. We created short sequences of visual or auditory items, such that each item within a sequence arose at a unique spatial location at a unique time. On each trial, two successive sequences were presented; subjects attended to either space (the sequence of locations), or time (the sequence of inter-item intervals), and reported whether the patterns of locations or intervals were identical. Each subject completed blocks of unimodal trials (both sequences presented in the same modality) and crossmodal trials (sequence 1 visual and sequence 2 auditory, or vice versa) for both spatial and temporal tasks. We found a strong interaction between modality and task: spatial performance was best on unimodal visual trials, while temporal performance was best on unimodal auditory trials. The order of modalities on crossmodal trials also mattered, suggesting that perceptual fidelity at encoding is critical to STM. Critically, there was no cost attributable to crossmodal comparison: in both tasks, performance on crossmodal trials was as good or better than on the weaker unimodal trials. STM representations of space and time can guide change detection in either the visual or the auditory modality, suggesting that temporal or spatial organization of STM may supersede sensory-specific organization. PMID:26791231

  12. Polar Applications of Spaceborne Scatterometers

    Science.gov (United States)

    Long, David G.

    2017-01-01

    Wind scatterometers were originally developed for observation of near-surface winds over the ocean. They retrieve wind indirectly by measuring the normalized radar cross section (σo) of the surface, and estimating the wind via a geophysical model function relating σo to the vector wind. The σo measurements have proven to be remarkably capable in studies of the polar regions where they can map snow cover; detect the freeze/thaw state of forest, tundra, and ice; map and classify sea ice; and track icebergs. Further, a long time series of scatterometer σo observations is available to support climate studies. In addition to fundamental scientific research, scatterometer data are operationally used for sea-ice mapping to support navigation. Scatterometers are, thus, invaluable tools for monitoring the polar regions. In this paper, a brief review of some of the polar applications of spaceborne wind scatterometer data is provided. The paper considers both C-band and Ku-band scatterometers, and the relative merits of fan-beam and pencil-beam scatterometers in polar remote sensing are discussed. PMID:28919936

  13. Scalable printed electronics: an organic decoder addressing ferroelectric non-volatile memory

    Science.gov (United States)

    Ng, Tse Nga; Schwartz, David E.; Lavery, Leah L.; Whiting, Gregory L.; Russo, Beverly; Krusor, Brent; Veres, Janos; Bröms, Per; Herlogsson, Lars; Alam, Naveed; Hagel, Olle; Nilsson, Jakob; Karlsson, Christer

    2012-01-01

    Scalable circuits of organic logic and memory are realized using all-additive printing processes. A 3-bit organic complementary decoder is fabricated and used to read and write non-volatile, rewritable ferroelectric memory. The decoder-memory array is patterned by inkjet and gravure printing on flexible plastics. Simulation models for the organic transistors are developed, enabling circuit designs tolerant of the variations in printed devices. We explain the key design rules in fabrication of complex printed circuits and elucidate the performance requirements of materials and devices for reliable organic digital logic. PMID:22900143

  14. The organization and neural substrates of human memory.

    Science.gov (United States)

    Squire, L R

    The neurology of memory has been illuminated by parallel studies of patients with circumscribed memory impairment and animal models of human amnesia. Human amnesia can occur as an isolated cognitive deficit that impairs the ability to learn new facts and episodes. In addition, memory can be affected for material learned many years prior to the onset of amnesia. The finding that some memory abilities are intact in amnesia (e.g., skill learning, word priming, and adaptation-level effects) has suggested that memory can be divided into two or more separate processes. Declarative memory affords the ability to store information explicitly and to retrieve it later as a conscious recollection. This form of memory depends on the integrity of the structures damaged in amnesia. Other, non-declarative kinds of memory afford the ability to change as the result of experience, but the information is available only through performance. Recent studies of a favorable human case provided strong evidence that the hippocampus is a critical component of the declarative memory system. Extensive convergent and divergent projections link the hippocampus to many areas of neocortex where processing and storage of new information is likely to occur. It is perhaps by way of these connections that the hippocampus operates upon and participates in declarative representations.

  15. Organization of the two-level memory in the image processing system on scanning measuring projectors

    International Nuclear Information System (INIS)

    Sychev, A.Yu.

    1977-01-01

    Discussed are the problems of improving the efficiency of the system for processing pictures taken in bubble chambers with the use of scanning measuring projectors. The system comprises 20 to 30 pro ectors linked with the ICL-1903A computer provided with a mainframe memory, 64 kilobytes in size. Because of the insufficient size of a mainframe memory, a part of the programs and data is located in a second-level memory, i.e. in an external memory. The analytical model described herein is used to analyze the effect of the memory organization on the characteristics of the system. It is shown that organization of pure procedures and introduction of the centralized control of the tWo-leVel memory result in substantial improvement of the efficiency of the picture processing system

  16. Differential patterns of contextual organization of memory in first-episode psychosis.

    Science.gov (United States)

    Murty, Vishnu P; McKinney, Rachel A; DuBrow, Sarah; Jalbrzikowski, Maria; Haas, Gretchen L; Luna, Beatriz

    2018-02-15

    Contextual information is used to support and organize episodic memory. Prior research has reliably shown memory deficits in psychosis; however, little research has characterized how this population uses contextual information during memory recall. We employed an approach founded in a computational framework of free recall to quantify how individuals with first episode of psychosis (FEP, N = 97) and controls (CON, N = 55) use temporal and semantic context to organize memory recall. Free recall was characterized using the Hopkins Verbal Learning Test-Revised (HVLT-R). We compared FEP and CON on three measures of free recall: proportion recalled, temporal clustering, and semantic clustering. Measures of temporal/semantic clustering quantified how individuals use contextual information to organize memory recall. We also assessed to what extent these measures relate to antipsychotic use and differentiated between different types of psychosis. We also explored the relationship between these measures and intelligence. In comparison to CON, FEP had reduced recall and less temporal clustering during free recall (p contextual organization of memory. IQ was related to free recall accuracy, but not the use of contextual information during recall in either group (p < 0.05, Bonferroni-corrected). These results show that in addition to deficits in memory recall, FEP differed in how they organize memories compared to CON.

  17. The organization of associative memory with lamination of elements ...

    African Journals Online (AJOL)

    . Processing of character sets is carried out on bit cutoffs in the associative memory at the same time. For the hardware support of steps of retrieval operation the original structure of the associative memory is offered. The structure contains new ...

  18. Materials for spaceborne laser systems

    International Nuclear Information System (INIS)

    Gusarov, A.

    2006-01-01

    Advanced laser systems are attracting a growing interest for space missions, in particular for LIDAR (LIght Detection And Ranging) applications. An important issue for the LIDARs is the very strict requirements on the optical performance and more specifically the need for a high optical output power combined with a nearly perfect output beam quality. These features are traditionally in conflict with each other. Thermally induced phase distortions indeed corrupt the beam quality of high-power solid-state lasers and it becomes increasingly difficult to maintain a good beam quality while increasing the output power. A possible solution of the problem is to use the optical phase conjugation, which provides a method to dynamically correct for those aberrations. A process by which phase-conjugated waves can be generated is the SBS (stimulated Brillouin scattering). SBS mirrors commonly used in terrestrial application are based on liquids or gases, which are not 'space-friendly' and often toxic. The solid-state alternative seems the most appropriate for space. Such PCMs (Phase-Conjugating Mirrors) have been the subject of many research efforts in recent years and a significant progress in improving their characteristics has been achieved. However, the issue of space qualification remains open. To address it, the European Space Agency initiated in 2004 the research project named Solid-State Phase Conjugation, Radiation Testing and Evaluation for Core Laser Technologies with the TRT (Thales Research and Technology), France, as the prime contractor, and the CSL (Centre Spatial de Liege) and SCKCEN as the subcontractors. The project is to be completed in 2006. To qualify a PCM for a spaceborne laser system, one has to address a number of specific issues. Such a component must be mechanically rugged to sustain vibrations during the launch phase, provide a low out-gassing to prevent optical surfaces contamination in vacuum, be highly reliable to operate properly without

  19. Solution-Processed Wide-Bandgap Organic Semiconductor Nanostructures Arrays for Nonvolatile Organic Field-Effect Transistor Memory.

    Science.gov (United States)

    Li, Wen; Guo, Fengning; Ling, Haifeng; Liu, Hui; Yi, Mingdong; Zhang, Peng; Wang, Wenjun; Xie, Linghai; Huang, Wei

    2018-01-01

    In this paper, the development of organic field-effect transistor (OFET) memory device based on isolated and ordered nanostructures (NSs) arrays of wide-bandgap (WBG) small-molecule organic semiconductor material [2-(9-(4-(octyloxy)phenyl)-9H-fluoren-2-yl)thiophene]3 (WG 3 ) is reported. The WG 3 NSs are prepared from phase separation by spin-coating blend solutions of WG 3 /trimethylolpropane (TMP), and then introduced as charge storage elements for nonvolatile OFET memory devices. Compared to the OFET memory device with smooth WG 3 film, the device based on WG 3 NSs arrays exhibits significant improvements in memory performance including larger memory window (≈45 V), faster switching speed (≈1 s), stable retention capability (>10 4 s), and reliable switching properties. A quantitative study of the WG 3 NSs morphology reveals that enhanced memory performance is attributed to the improved charge trapping/charge-exciton annihilation efficiency induced by increased contact area between the WG 3 NSs and pentacene layer. This versatile solution-processing approach to preparing WG 3 NSs arrays as charge trapping sites allows for fabrication of high-performance nonvolatile OFET memory devices, which could be applicable to a wide range of WBG organic semiconductor materials. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Estradiol enhances retention but not organization of hippocampus-dependent memory in intact male mice.

    Science.gov (United States)

    Al Abed, Alice Shaam; Sellami, Azza; Brayda-Bruno, Laurent; Lamothe, Valérie; Noguès, Xavier; Potier, Mylène; Bennetau-Pelissero, Catherine; Marighetto, Aline

    2016-07-01

    Because estrogens have mostly been studied in gonadectomized females, effects of chronic exposure to environmental estrogens in the general population are underestimated. Estrogens can enhance hippocampus-dependent memory through the modulation of information storage. However, declarative memory, the hippocampus-dependent memory of facts and events, demands more than abilities to retain information. Specifically, memory of repetitive events of everyday life such as "where I parked" requires abilities to organize/update memories to prevent proactive interference from similar memories of previous "parking events". Whether such organizational processes are estrogen-sensitive is unknown. We here studied, in intact young and aged adult mice, drinking-water (1μM) estradiol effects on both retention and organizational components of hippocampus-dependent memory, using a radial-maze task of everyday-like memory. Demand on retention vs organization was manipulated by varying the time-interval separating repetitions of similar events. Estradiol increased performance in young and aged mice under minimized organizational demand, but failed to improve the age-associated memory impairment and diminished performance in young mice under high organizational demand. In fact, estradiol prolonged mnemonic retention of successive events without improving organization abilities, hence resulted in more proactive interference from irrelevant memories. c-Fos imaging of testing-induced brain activations showed that the deterioration of young memory was associated with dentate gyrus dysconnectivity, reminiscent of that seen in aged mice. Our findings support the view that estradiol is promnesic but also reveal that such property can paradoxically impair memory. These findings have important outcomes regarding health issues relative to the impact of environmental estrogens in the general population. Copyright © 2016 Elsevier Ltd. All rights reserved.

  1. Dopamine D1 signaling organizes network dynamics underlying working memory.

    Science.gov (United States)

    Roffman, Joshua L; Tanner, Alexandra S; Eryilmaz, Hamdi; Rodriguez-Thompson, Anais; Silverstein, Noah J; Ho, New Fei; Nitenson, Adam Z; Chonde, Daniel B; Greve, Douglas N; Abi-Dargham, Anissa; Buckner, Randy L; Manoach, Dara S; Rosen, Bruce R; Hooker, Jacob M; Catana, Ciprian

    2016-06-01

    Local prefrontal dopamine signaling supports working memory by tuning pyramidal neurons to task-relevant stimuli. Enabled by simultaneous positron emission tomography-magnetic resonance imaging (PET-MRI), we determined whether neuromodulatory effects of dopamine scale to the level of cortical networks and coordinate their interplay during working memory. Among network territories, mean cortical D1 receptor densities differed substantially but were strongly interrelated, suggesting cross-network regulation. Indeed, mean cortical D1 density predicted working memory-emergent decoupling of the frontoparietal and default networks, which respectively manage task-related and internal stimuli. In contrast, striatal D1 predicted opposing effects within these two networks but no between-network effects. These findings specifically link cortical dopamine signaling to network crosstalk that redirects cognitive resources to working memory, echoing neuromodulatory effects of D1 signaling on the level of cortical microcircuits.

  2. Overview of one transistor type of hybrid organic ferroelectric non-volatile memory

    Institute of Scientific and Technical Information of China (English)

    Young; Tea; Chun; Daping; Chu

    2015-01-01

    Organic ferroelectric memory devices based on field effect transistors that can be configured between two stable states of on and off have been widely researched as the next generation data storage media in recent years.This emerging type of memory devices can lead to a new instrument system as a potential alternative to previous non-volatile memory building blocks in future processing units because of their numerous merits such as cost-effective process,simple structure and freedom in substrate choices.This bi-stable non-volatile memory device of information storage has been investigated using several organic or inorganic semiconductors with organic ferroelectric polymer materials.Recent progresses in this ferroelectric memory field,hybrid system have attracted a lot of attention due to their excellent device performance in comparison with that of all organic systems.In this paper,a general review of this type of ferroelectric non-volatile memory is provided,which include the device structure,organic ferroelectric materials,electrical characteristics and working principles.We also present some snapshots of our previous study on hybrid ferroelectric memories including our recent work based on zinc oxide nanowire channels.

  3. Temporal Organization of Sound Information in Auditory Memory

    OpenAIRE

    Song, Kun; Luo, Huan

    2017-01-01

    Memory is a constructive and organizational process. Instead of being stored with all the fine details, external information is reorganized and structured at certain spatiotemporal scales. It is well acknowledged that time plays a central role in audition by segmenting sound inputs into temporal chunks of appropriate length. However, it remains largely unknown whether critical temporal structures exist to mediate sound representation in auditory memory. To address the issue, here we designed ...

  4. Development in the Organization of Episodic Memories in Middle Childhood and Adolescence

    Directory of Open Access Journals (Sweden)

    Yan eChen

    2013-07-01

    Full Text Available The basic elements of autobiographical or episodic memory are established in early childhood, although the exact age at which memories gain episodic status is still under contention. The self-memory system proposed that adults use lifetime periods to group episodic memories together into life story chapters. Two studies examined at what point in development children or adolescents begin to take advantage of lifetime-period chapters to organize their episodic memories. The results of Study 1 with 8- to 12-year-olds revealed that the ability to provide life story chapters began to emerge as early as 8 years of age. In Study 2 with adolescents aged 12 to 21, this ability continued to develop into late adolescence among New Zealand European and New Zealand Chinese adolescents; however, cultural differences also existed in the specificity of memories. New Zealand Chinese adolescents narrated fewer life story chapters containing specific memories than New Zealand European adolescents. These findings support and extend current theories of episodic memory by specifying that pre-adolescents are starting to organize their episodic memories into lifetime periods, but this achievement is not fully realized until later in adolescence.

  5. Development in the organization of episodic memories in middle childhood and adolescence.

    Science.gov (United States)

    Chen, Yan; McAnally, Helena Margaret; Reese, Elaine

    2013-01-01

    The basic elements of autobiographical or episodic memory are established in early childhood, although the exact age at which memories gain episodic status is still under contention. The self-memory system proposed that adults use "lifetime periods" to group episodic memories together into chapters of the life story - an evolving and internalized account of significant life events that are self-defining. Two studies examined at what point in development children or adolescents begin to take advantage of lifetime-period chapters to organize their episodic memories. The results of Study 1 with 8- to 12-year-olds revealed that the ability to provide life story chapters began to emerge as early as 8 years of age. In Study 2 with adolescents aged 12-21, this ability continued to develop into late adolescence among New Zealand European (NZE) and New Zealand Chinese (NZC) adolescents; however, cultural differences also existed in the specificity of memories. NZC adolescents narrated fewer life story chapters containing specific memories than NZE adolescents. These findings support and extend current theories of episodic memory by specifying that pre-adolescents are starting to organize their episodic memories into lifetime periods, but this achievement is not fully realized until later in adolescence.

  6. Associative memory for online learning in noisy environments using self-organizing incremental neural network.

    Science.gov (United States)

    Sudo, Akihito; Sato, Akihiro; Hasegawa, Osamu

    2009-06-01

    Associative memory operating in a real environment must perform well in online incremental learning and be robust to noisy data because noisy associative patterns are presented sequentially in a real environment. We propose a novel associative memory that satisfies these requirements. Using the proposed method, new associative pairs that are presented sequentially can be learned accurately without forgetting previously learned patterns. The memory size of the proposed method increases adaptively with learning patterns. Therefore, it suffers neither redundancy nor insufficiency of memory size, even in an environment in which the maximum number of associative pairs to be presented is unknown before learning. Noisy inputs in real environments are classifiable into two types: noise-added original patterns and faultily presented random patterns. The proposed method deals with two types of noise. To our knowledge, no conventional associative memory addresses noise of both types. The proposed associative memory performs as a bidirectional one-to-many or many-to-one associative memory and deals not only with bipolar data, but also with real-valued data. Results demonstrate that the proposed method's features are important for application to an intelligent robot operating in a real environment. The originality of our work consists of two points: employing a growing self-organizing network for an associative memory, and discussing what features are necessary for an associative memory for an intelligent robot and proposing an associative memory that satisfies those requirements.

  7. Organic field-effect transistor nonvolatile memories utilizing sputtered C nanoparticles as nano-floating-gate

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jie; Liu, Chang-Hai; She, Xiao-Jian; Sun, Qi-Jun; Gao, Xu; Wang, Sui-Dong, E-mail: wangsd@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu 215123 (China)

    2014-10-20

    High-performance organic field-effect transistor nonvolatile memories have been achieved using sputtered C nanoparticles as the nano-floating-gate. The sputtered C nano-floating-gate is prepared with low-cost material and simple process, forming uniform and discrete charge trapping sites covered by a smooth and complete polystyrene layer. The devices show large memory window, excellent retention capability, and programming/reading/erasing/reading endurance. The sputtered C nano-floating-gate can effectively trap both holes and electrons, and it is demonstrated to be suitable for not only p-type but also n-type organic field-effect transistor nonvolatile memories.

  8. Organic field-effect transistor nonvolatile memories utilizing sputtered C nanoparticles as nano-floating-gate

    International Nuclear Information System (INIS)

    Liu, Jie; Liu, Chang-Hai; She, Xiao-Jian; Sun, Qi-Jun; Gao, Xu; Wang, Sui-Dong

    2014-01-01

    High-performance organic field-effect transistor nonvolatile memories have been achieved using sputtered C nanoparticles as the nano-floating-gate. The sputtered C nano-floating-gate is prepared with low-cost material and simple process, forming uniform and discrete charge trapping sites covered by a smooth and complete polystyrene layer. The devices show large memory window, excellent retention capability, and programming/reading/erasing/reading endurance. The sputtered C nano-floating-gate can effectively trap both holes and electrons, and it is demonstrated to be suitable for not only p-type but also n-type organic field-effect transistor nonvolatile memories.

  9. Elastic pointer directory organization for scalable shared memory multiprocessors

    Institute of Scientific and Technical Information of China (English)

    Yuhang Liu; Mingfa Zhu; Limin Xiao

    2014-01-01

    In the field of supercomputing, one key issue for scal-able shared-memory multiprocessors is the design of the directory which denotes the sharing state for a cache block. A good direc-tory design intends to achieve three key attributes: reasonable memory overhead, sharer position precision and implementation complexity. However, researchers often face the problem that gain-ing one attribute may result in losing another. The paper proposes an elastic pointer directory (EPD) structure based on the analysis of shared-memory applications, taking the fact that the number of sharers for each directory entry is typical y smal . Analysis re-sults show that for 4 096 nodes, the ratio of memory overhead to the ful-map directory is 2.7%. Theoretical analysis and cycle-accurate execution-driven simulations on a 16 and 64-node cache coherence non uniform memory access (CC-NUMA) multiproces-sor show that the corresponding pointer overflow probability is reduced significantly. The performance is observed to be better than that of a limited pointers directory and almost identical to the ful-map directory, except for the slight implementation complex-ity. Using the directory cache to explore directory access locality is also studied. The experimental result shows that this is a promis-ing approach to be used in the state-of-the-art high performance computing domain.

  10. A High-Performance Optical Memory Array Based on Inhomogeneity of Organic Semiconductors.

    Science.gov (United States)

    Pei, Ke; Ren, Xiaochen; Zhou, Zhiwen; Zhang, Zhichao; Ji, Xudong; Chan, Paddy Kwok Leung

    2018-03-01

    Organic optical memory devices keep attracting intensive interests for diverse optoelectronic applications including optical sensors and memories. Here, flexible nonvolatile optical memory devices are developed based on the bis[1]benzothieno[2,3-d;2',3'-d']naphtho[2,3-b;6,7-b']dithiophene (BBTNDT) organic field-effect transistors with charge trapping centers induced by the inhomogeneity (nanosprouts) of the organic thin film. The devices exhibit average mobility as high as 7.7 cm 2 V -1 s -1 , photoresponsivity of 433 A W -1 , and long retention time for more than 6 h with a current ratio larger than 10 6 . Compared with the standard floating gate memory transistors, the BBTNDT devices can reduce the fabrication complexity, cost, and time. Based on the reasonable performance of the single device on a rigid substrate, the optical memory transistor is further scaled up to a 16 × 16 active matrix array on a flexible substrate with operating voltage less than 3 V, and it is used to map out 2D optical images. The findings reveal the potentials of utilizing [1]benzothieno[3,2-b][1]benzothiophene (BTBT) derivatives as organic semiconductors for high-performance optical memory transistors with a facile structure. A detailed study on the charge trapping mechanism in the derivatives of BTBT materials is also provided, which is closely related to the nanosprouts formed inside the organic active layer. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Differential pattern of semantic memory organization between bipolar I and II disorders.

    Science.gov (United States)

    Chang, Jae Seung; Choi, Sungwon; Ha, Kyooseob; Ha, Tae Hyon; Cho, Hyun Sang; Choi, Jung Eun; Cha, Boseok; Moon, Eunsoo

    2011-06-01

    Semantic cognition is one of the key factors in psychosocial functioning. The aim of this study was to explore the differences in pattern of semantic memory organization between euthymic patients with bipolar I and II disorders using the category fluency task. Study participants included 23 euthymic subjects with bipolar I disorder, 23 matched euthymic subjects with bipolar II disorder and 23 matched control subjects. All participants were assessed for verbal learning, recall, learning strategies, and fluency. The combined methods of hierarchical clustering and multidimensional scaling were used to compare the pattern of semantic memory organization among the three groups. Quantitative measures of verbal learning, recall, learning strategies, and fluency did not differ between the three groups. A two-cluster structure of semantic memory organization was identified for the three groups. Semantic structure was more disorganized in the bipolar I disorder group compared to the bipolar II disorder. In addition, patients with bipolar II disorder used less elaborate strategies of semantic memory organization than those of controls. Compared to healthy controls, strategies for categorization in semantic memory appear to be less knowledge-based in patients with bipolar disorders. A differential pattern of semantic memory organization between bipolar I and II disorders indicates a higher risk of cognitive abnormalities in patients with bipolar I disorder compared to patients with bipolar II disorder. Exploring qualitative nature of neuropsychological domains may provide an explanatory insight into the characteristic behaviors of patients with bipolar disorders. Copyright © 2011 Elsevier Inc. All rights reserved.

  12. Memory

    Science.gov (United States)

    ... it has to decide what is worth remembering. Memory is the process of storing and then remembering this information. There are different types of memory. Short-term memory stores information for a few ...

  13. Organic ferroelectric/semiconducting nanowire hybrid layer for memory storage

    NARCIS (Netherlands)

    Cai, R.; Kassa, H.G.; Haouari, R.; Marrani, A.; Geerts, Y.H.; Ruzié, C.; Breemen, A.J.J.M. van; Gelinck, G.H.; Nysten, B.; Hu, Z.; Jonas, A.M.

    2016-01-01

    Ferroelectric materials are important components of sensors, actuators and non-volatile memories. However, possible device configurations are limited due to the need to provide screening charges to ferroelectric interfaces to avoid depolarization. Here we show that, by alternating ferroelectric and

  14. The organization of Romanian social memory after the December 1989 events

    Directory of Open Access Journals (Sweden)

    Constantin-Ovidiu Craiu

    2013-12-01

    Full Text Available The social memory phenomenon causes debates nowadays, puts in opposition methodological schools, generates a series of incompatible theoretical positions. Proof that the concept of “social memory” “lived” its first age are the numerous research which regards the phenomenon, studies which led either to new theories of social memory (the theory of the organization of memory according to culture and interests is one of the acknowledged theories from which it starts in the development of the subject, or they certified the ones established until then. The present paper proposes as its objective to evaluate the factors which led to the readjustment of the social memory of the Romanian people after the events from 1989. I consider that the social memory can be organized under the influence of factors which acts unitary. As a result, I will analyze the connection between the political factor (decision – maker agents that can influence some contents of the collective memory and the social one (the public opinion of the group that undergoes major alterations regarding the contents of memory. I initiated the investigation approach from the observation that certain contents of the social memory resignify themselves through the direct influence of the social group, the power structure having the role of putting into practice the community’s “desire”. The necessity of a unitary co-operation between the community and the decision factor for the achievement of a new mnezic construction is imperative. For that purpose, I will analyze the effects of the non-unitary actions of these factors against the social memory, being known that not always the decision factor and the social factor (the community have the same attitudes towards certain mnesic contents. One can observe certain patterns concerning the organization of social memory in relation to these two factors, being analyzed the intentionality (what the two parts desire and the purpose (the

  15. What does the functional organization of cortico-hippocampal networks tell us about the functional organization of memory?

    Science.gov (United States)

    Reagh, Zachariah M; Ranganath, Charan

    2018-04-25

    Historically, research on the cognitive processes that support human memory proceeded, to a large extent, independently of research on the neural basis of memory. Accumulating evidence from neuroimaging, however, has enabled the field to develop a broader and more integrative perspective. Here, we briefly outline how advances in cognitive neuroscience can potentially shed light on concepts and controversies in human memory research. We argue that research on the functional properties of cortico-hippocampal networks informs us about how memories might be organized in the brain, which, in turn, helps to reconcile seemingly disparate perspectives in cognitive psychology. Finally, we discuss several open questions and directions for future research. Copyright © 2018. Published by Elsevier B.V.

  16. Organic electronic memory based on a ferroelectric polymer

    Energy Technology Data Exchange (ETDEWEB)

    Kalbitz, R; Fruebing, P; Gerhard, R [Department of Physics and Astronomy, University of Potsdam, Karl-Liebknecht Str., 24-25, 14476 Potsdam (Germany); Taylor, D M, E-mail: d.m.taylor@bangor.ac.uk [School of Electronic Engineering, Bangor University, Dean Street, Bangor, Gwynedd LL57 1UT (United Kingdom)

    2011-06-23

    Measurements of the capacitance of metal-insulator-semiconductor capacitors and the output characteristics of thin film transistors based on poly(3-hexylthiophene) as the active semiconductor and poly(vinylidenefluoride-trifluoroethylene) as the gate insulator show that ferroelectric polarisation in the insulator is stable but that its effect when poled by depletion voltages is partially neutralised by trapping of electrons at or near the semiconductor interface. Nevertheless, the combination of materials is capable of providing an adequate memory function.

  17. Metal-organic molecular device for non-volatile memory storage

    International Nuclear Information System (INIS)

    Radha, B.; Sagade, Abhay A.; Kulkarni, G. U.

    2014-01-01

    Non-volatile memory devices have been of immense research interest for their use in active memory storage in powered off-state of electronic chips. In literature, various molecules and metal compounds have been investigated in this regard. Molecular memory devices are particularly attractive as they offer the ease of storing multiple memory states in a unique way and also represent ubiquitous choice for miniaturized devices. However, molecules are fragile and thus the device breakdown at nominal voltages during repeated cycles hinders their practical applicability. Here, in this report, a synergetic combination of an organic molecule and an inorganic metal, i.e., a metal-organic complex, namely, palladium hexadecylthiolate is investigated for memory device characteristics. Palladium hexadecylthiolate following partial thermolysis is converted to a molecular nanocomposite of Pd(II), Pd(0), and long chain hydrocarbons, which is shown to exhibit non-volatile memory characteristics with exceptional stability and retention. The devices are all solution-processed and the memory action stems from filament formation across the pre-formed cracks in the nanocomposite film.

  18. Soluble dendrimers europium(III) β-diketonate complex for organic memory devices

    International Nuclear Information System (INIS)

    Wang Binbin; Fang Junfeng; Li Bin; You Han; Ma Dongge; Hong Ziruo; Li Wenlian; Su Zhongmin

    2008-01-01

    We report the synthesis of a soluble dendrimers europium(III) complex, tris(dibenzoylmethanato)(1,3,5-tris[2-(2'-pyridyl) benzimidazoly]methylbenzene)-europium(III), and its application in organic electrical bistable memory device. Excellent stability that ensured more than 10 6 write-read-erase-reread cycles has been performed in ambient conditions without current-induced degradation. High-density, low-cost memory, good film-firming property, fascinating thermal and morphological stability allow the application of the dendrimers europium(III) complex as an active medium in non-volatile memory devices

  19. Ambipolar organic thin-film transistor-based nano-floating-gate nonvolatile memory

    International Nuclear Information System (INIS)

    Han, Jinhua; Wang, Wei; Ying, Jun; Xie, Wenfa

    2014-01-01

    An ambipolar organic thin-film transistor-based nano-floating-gate nonvolatile memory was demonstrated, with discrete distributed gold nanoparticles, tetratetracontane (TTC), pentacene as the floating-gate layer, tunneling layer, and active layer, respectively. The electron traps at the TTC/pentacene interface were significantly suppressed, which resulted in an ambipolar operation in present memory. As both electrons and holes were supplied in the channel and trapped in the floating-gate by programming/erasing operations, respectively, i.e., one type of charge carriers was used to overwrite the other, trapped, one, a large memory window, extending on both sides of the initial threshold voltage, was realized

  20. Ambipolar organic thin-film transistor-based nano-floating-gate nonvolatile memory

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jinhua; Wang, Wei, E-mail: wwei99@jlu.edu.cn; Ying, Jun; Xie, Wenfa [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012 (China)

    2014-01-06

    An ambipolar organic thin-film transistor-based nano-floating-gate nonvolatile memory was demonstrated, with discrete distributed gold nanoparticles, tetratetracontane (TTC), pentacene as the floating-gate layer, tunneling layer, and active layer, respectively. The electron traps at the TTC/pentacene interface were significantly suppressed, which resulted in an ambipolar operation in present memory. As both electrons and holes were supplied in the channel and trapped in the floating-gate by programming/erasing operations, respectively, i.e., one type of charge carriers was used to overwrite the other, trapped, one, a large memory window, extending on both sides of the initial threshold voltage, was realized.

  1. A model of cognitive and operational memory of organizations in changing worlds

    OpenAIRE

    Giovanni Dosi; Luigi Marengo; Evita Paraskevopoulou; Marco Valente

    2015-01-01

    This work analyzes and models the nature and dynamics of organizational memory, as such an essential ingredient of organizational capabilities. There are two sides to it, namely a cognitive side, involving the beliefs and interpretative frameworks by which the organization categorizes the states of the world and its own internal states, and an operational one, including routines and procedures that store the knowledge of how to do things. We formalize both types of memory by means of evolving...

  2. Infrastructure monitoring with spaceborne SAR sensors

    CERN Document Server

    ANGHEL, ANDREI; CACOVEANU, REMUS

    2017-01-01

    This book presents a novel non-intrusive infrastructure monitoring technique based on the detection and tracking of scattering centers in spaceborne SAR images. The methodology essentially consists of refocusing each available SAR image on an imposed 3D point cloud associated to the envisaged infrastructure element and identifying the reliable scatterers to be monitored by means of four dimensional (4D) tomography. The methodology described in this book provides a new perspective on infrastructure monitoring with spaceborne SAR images, is based on a standalone processing chain, and brings innovative technical aspects relative to conventional approaches. The book is intended primarily for professionals and researchers working in the area of critical infrastructure monitoring by radar remote sensing.

  3. Part I: the effect of long-term exposure to organic solvents on memory: a cross sectional study.

    Science.gov (United States)

    Ratzon, N Z; Vakil, E; Derazne, E; Sculsky, M

    1998-01-01

    This study focuses on a wide range of different aspects of memory functions trying to ascertain a possible profile of memory changes, which take place following long-term exposure to organic solvents. The research design was cross-sectional. Study population included 31 industrial painters who were exposed at work to organic solvents and 31 unexposed workers. Workers after long-term exposure to organic solvents showed significant decline in memory as indicated in all three standard memory tests (i.e. Wechsler Memory Scale - Revised, Benton Revised Visual Retention Test, and Rey Auditory Verbal Learning Test). The results of Rey Auditory Verbal Learning Test showed a negative correlation with exposure index indicating that the more intensive and longer the time of exposure was, the more impaired is the verbal memory. It was also found that the affect of age on memory was stronger among workers after long-term exposure to organic solvents compared to the unexposed workers.

  4. The ultrametric organization of memories in a neural network

    International Nuclear Information System (INIS)

    Parga, N.; Virasoro, M.A.

    1985-08-01

    In Hopfield's model of human memory the words to be stored must be orthogonal. From the point of view of human psychology this feature is unacceptable unless we reinterpret these words as primordial categories. But then one has to complete the model so as to be able to store a full hierarchical tree of categories embodying subcategories and so on. We use recent results on the spin glass mean field theories to show that this complementation can be done in a natural way with a minimal modification of Hebb's rule for learning. Categorization emerges naturally from an encoding stage structured in layers. (author)

  5. Organic non-volatile memories from ferroelectric phase separated blends

    Science.gov (United States)

    Asadi, Kamal; de Leeuw, Dago; de Boer, Bert; Blom, Paul

    2009-03-01

    Ferroelectric polarisation is an attractive physical property for non-volatile binary switching. The functionality of the targeted memory should be based on resistive switching. Conductivity and ferroelectricity however cannot be tuned independently. The challenge is to develop a storage medium in which the favourable properties of ferroelectrics such as bistability and non-volatility can be combined with the beneficial properties provided by semiconductors such as conductivity and rectification. In this contribution we present an integrated solution by blending semiconducting and ferroelectric polymers into phase separated networks. The polarisation field of the ferroelectric modulates the injection barrier at the semiconductor--metal contact. This combination allows for solution-processed non-volatile memory arrays with a simple cross-bar architecture that can be read-out non-destructively. Based on this general concept a non-volatile, reversible switchable Schottky diode with relatively fast programming time of shorter than 100 microseconds, long information retention time of longer than 10^ days, and high programming cycle endurance with non-destructive read-out is demonstrated.

  6. Resistive switching characteristics of solution-processed organic-inorganic blended films for flexible memory applications

    Science.gov (United States)

    Baek, Il-Jin; Cho, Won-Ju

    2018-02-01

    We developed a hybrid organic-inorganic resistive random access memory (ReRAM) device that uses a solution-process to overcome the disadvantages of organic and inorganic materials for flexible memory applications. The drawbacks of organic and inorganic materials are a poor electrical characteristics and a lack of flexibility, respectively. We fabricated a hybrid organic-inorganic switching layer of ReRAM by blending HfOx or AlOx solution with PMMA solution and investigated the resistive switching behaviour in Ti/PMMA/Pt, Ti/PMMA-HfOx/Pt and Ti/PMMA-AlOx/Pt structures. It is found that PMMA-HfOx or PMMA-AlOx hybrid switching layer has a larger memory window, more stable durability and retention characteristics, and a better set/reset voltage distribution than PMMA layer. Further, it is confirmed that the flexibility of the PMMA-HfOx and PMMA-AlOx blended films was almost similar to that of the organic PMMA film. Thus, the solution-processed organic-inorganic blended films are considered a promising material for a non-volatile memory device on a flexible or wearable electronic system.

  7. Quasi-unipolar pentacene films embedded with fullerene for non-volatile organic transistor memories

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Juhee; Lee, Sungpyo; Lee, Moo Hyung; Kang, Moon Sung, E-mail: mskang@ssu.ac.kr [Department of Chemical Engineering, Soongsil University, Seoul 156-743 (Korea, Republic of)

    2015-02-09

    Quasi-unipolar non-volatile organic transistor memory (NOTM) can combine the best characteristics of conventional unipolar and ambipolar NOTMs and, as a result, exhibit improved device performance. Unipolar NOTMs typically exhibit a large signal ratio between the programmed and erased current signals but also require a large voltage to program and erase the memory cells. Meanwhile, an ambipolar NOTM can be programmed and erased at lower voltages, but the resulting signal ratio is small. By embedding a discontinuous n-type fullerene layer within a p-type pentacene film, quasi-unipolar NOTMs are fabricated, of which the signal storage utilizes both electrons and holes while the electrical signal relies on only hole conduction. These devices exhibit superior memory performance relative to both pristine unipolar pentacene devices and ambipolar fullerene/pentacene bilayer devices. The quasi-unipolar NOTM exhibited a larger signal ratio between the programmed and erased states while also reducing the voltage required to program and erase a memory cell. This simple approach should be readily applicable for various combinations of advanced organic semiconductors that have been recently developed and thereby should make a significant impact on organic memory research.

  8. Silver nanoparticles alter learning and memory formation in an aquatic organism, Lymnaea stagnalis.

    Science.gov (United States)

    Young, Austin; Protheroe, Amy; Lukowiak, Ken

    2017-06-01

    We tested the effect of silver nanoparticles (AgNPs) on the ability of the pond snail, Lymnaea stagnalis, to learn and form long-term memory (LTM) following operant conditioning of aerial respiration. We hypothesized that the AgNPs would act as a stressor and prevent learning and LTM formation. We tested snails exposed for either 72 h or only during training and testing for memory (i.e. 0.5 h) and found no difference between those treatments. We found that at a low concentration of AgNPs (5 μg/L) neither learning and nor memory formation were altered. When we increased the concentration of AgNPs (10 μg/L) we found that memory formation was enhanced. Finally, at a higher concentration (50 μg/L) memory formation was blocked. To determine if the disassociation of Ag + from the AgNPs caused the effects on memory we performed similar experiments with AgNO 3 and found similar concentration-dependent results. Finally, we found that snails perceive the AgNPs differently from Ag+ as there was context specific memory. That is, snails trained in AgNPs did not show memory when tested in Ag + and vice-versa. We believe that changes in memory formation may be a more sensitive determination of AgNPs on aquatic organisms than the determination of a LC 50 . Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  9. Surface engineering of ferroelectric polymer for the enhanced electrical performance of organic transistor memory

    Science.gov (United States)

    Kim, Do-Kyung; Lee, Gyu-Jeong; Lee, Jae-Hyun; Kim, Min-Hoi; Bae, Jin-Hyuk

    2018-05-01

    We suggest a viable surface control method to improve the electrical properties of organic nonvolatile memory transistors. For viable surface control, the surface of the ferroelectric insulator in the memory field-effect transistors was modified using a smooth-contact-curing process. For the modification of the ferroelectric polymer, during the curing of the ferroelectric insulators, the smooth surface of a soft elastomer contacts intimately with the ferroelectric surface. This smooth-contact-curing process reduced the surface roughness of the ferroelectric insulator without degrading its ferroelectric properties. The reduced roughness of the ferroelectric insulator increases the mobility of the organic field-effect transistor by approximately eight times, which results in a high memory on–off ratio and a low-voltage reading operation.

  10. High-Performance Nonvolatile Organic Field-Effect Transistor Memory Based on Organic Semiconductor Heterostructures of Pentacene/P13/Pentacene as Both Charge Transport and Trapping Layers.

    Science.gov (United States)

    Li, Wen; Guo, Fengning; Ling, Haifeng; Zhang, Peng; Yi, Mingdong; Wang, Laiyuan; Wu, Dequn; Xie, Linghai; Huang, Wei

    2017-08-01

    Nonvolatile organic field-effect transistor (OFET) memory devices based on pentacene/ N , N '-ditridecylperylene-3,4,9,10-tetracarboxylic diimide (P13)/pentacene trilayer organic heterostructures have been proposed. The discontinuous n-type P13 embedded in p-type pentacene layers can not only provide electrons in the semiconductor layer that facilitates electron trapping process; it also works as charge trapping sites, which is attributed to the quantum well-like pentacene/P13/pentacene organic heterostructures. The synergistic effects of charge trapping in the discontinuous P13 and the charge-trapping property of the poly(4-vinylphenol) (PVP) layer remarkably improve the memory performance. In addition, the trilayer organic heterostructures have also been successfully applied to multilevel and flexible nonvolatile memory devices. The results provide a novel design strategy to achieve high-performance nonvolatile OFET memory devices and allow potential applications for different combinations of various organic semiconductor materials in OFET memory.

  11. Poly(3,4-ethylenedioxythiophene)-Poly(styrenesulfonate) Interlayer Insertion Enables Organic Quaternary Memory.

    Science.gov (United States)

    Cheng, Xue-Feng; Hou, Xiang; Qian, Wen-Hu; He, Jing-Hui; Xu, Qing-Feng; Li, Hua; Li, Na-Jun; Chen, Dong-Yun; Lu, Jian-Mei

    2017-08-23

    Herein, for the first time, quaternary resistive memory based on an organic molecule is achieved via surface engineering. A layer of poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT-PSS) was inserted between the indium tin oxide (ITO) electrode and the organic layer (squaraine, SA-Bu) to form an ITO/PEDOT-PSS/SA-Bu/Al architecture. The modified resistive random-access memory (RRAM) devices achieve quaternary memory switching with the highest yield (∼41%) to date. Surface morphology, crystallinity, and mosaicity of the deposited organic grains are greatly improved after insertion of a PEDOT-PSS interlayer, which provides better contacts at the grain boundaries as well as the electrode/active layer interface. The PEDOT-PSS interlayer also reduces the hole injection barrier from the electrode to the active layer. Thus, the threshold voltage of each switching is greatly reduced, allowing for more quaternary switching in a certain voltage window. Our results provide a simple yet powerful strategy as an alternative to molecular design to achieve organic quaternary resistive memory.

  12. Plausible carrier transport model in organic-inorganic hybrid perovskite resistive memory devices

    Science.gov (United States)

    Park, Nayoung; Kwon, Yongwoo; Choi, Jaeho; Jang, Ho Won; Cha, Pil-Ryung

    2018-04-01

    We demonstrate thermally assisted hopping (TAH) as an appropriate carrier transport model for CH3NH3PbI3 resistive memories. Organic semiconductors, including organic-inorganic hybrid perovskites, have been previously speculated to follow the space-charge-limited conduction (SCLC) model. However, the SCLC model cannot reproduce the temperature dependence of experimental current-voltage curves. Instead, the TAH model with temperature-dependent trap densities and a constant trap level are demonstrated to well reproduce the experimental results.

  13. Feature-Based Visual Short-Term Memory Is Widely Distributed and Hierarchically Organized.

    Science.gov (United States)

    Dotson, Nicholas M; Hoffman, Steven J; Goodell, Baldwin; Gray, Charles M

    2018-06-15

    Feature-based visual short-term memory is known to engage both sensory and association cortices. However, the extent of the participating circuit and the neural mechanisms underlying memory maintenance is still a matter of vigorous debate. To address these questions, we recorded neuronal activity from 42 cortical areas in monkeys performing a feature-based visual short-term memory task and an interleaved fixation task. We find that task-dependent differences in firing rates are widely distributed throughout the cortex, while stimulus-specific changes in firing rates are more restricted and hierarchically organized. We also show that microsaccades during the memory delay encode the stimuli held in memory and that units modulated by microsaccades are more likely to exhibit stimulus specificity, suggesting that eye movements contribute to visual short-term memory processes. These results support a framework in which most cortical areas, within a modality, contribute to mnemonic representations at timescales that increase along the cortical hierarchy. Copyright © 2018 Elsevier Inc. All rights reserved.

  14. Organizing of delay, input gate and memory of proportional chamber channel basing on D-trigger

    International Nuclear Information System (INIS)

    Vladimirov, S.V.; Kuzichev, V.F.; Rabin, N.V.

    1980-01-01

    Economical organization of delay, input gate and proportional chamber (PC) channel memory on the 155 TM2 D trigger basis is described. The channel consists of an amplifier; delay element permitting to synchronize PC signal and recording strobe-signal; input gate, where coincidence of the above signals occurs; memory element, where the data from a wire are recorded and stored; read gate through which the data are transmitted for further processing. Presented is one of the versions of circuit solution for delay element, input gate and momory element. Flowsheet peculiarity is the simplicity of fabrication and tuning as well as low cost of the device

  15. Dependence of the organic nonvolatile memory performance on the location of ultra-thin Ag film

    International Nuclear Information System (INIS)

    Jiao Bo; Wu Zhaoxin; He Qiang; Mao Guilin; Hou Xun; Tian Yuan

    2010-01-01

    We demonstrated organic nonvolatile memory devices based on 4,4',4''-tris[N-(3-methylphenyl)-N-phenylamino] triphenylamine (m-MTDATA) inserted by an ultra-thin Ag film. The memory devices with different locations of ultra-thin Ag film in m-MTDATA were investigated, and it was found that the location of the Ag film could affect the performance of the organic memory, such as ON/OFF ratio, retention time and cycling endurance. When the Ag film was located at the ITO/m-MTDATA interface, the largest ON/OFF ratio (about 10 5 ) could be achieved, but the cycling endurance was poor. When the Ag film was located in the middle region of the m-MTDATA layer, the ON/OFF ratios came down by about 10 3 , but better performance of cycling endurance was exhibited. When the Ag film was located close to the Al electrode, the ON/OFF ratios and the retention time of this device decreased sharply and the bistable phenomenon almost disappeared. Our works show a simple approach to improve the performance of organic memory by adjusting the location of the metal film.

  16. Ionospheric correction for spaceborne single-frequency GPS based ...

    Indian Academy of Sciences (India)

    A modified ionospheric correction method and the corresponding approximate algorithm for spaceborne single-frequency Global Positioning System (GPS) users are proposed in this study. Single Layer Model (SLM) mapping function for spaceborne GPS was analyzed. SLM mapping functions at different altitudes were ...

  17. Prefrontal θ-Burst Stimulation Disrupts the Organizing Influence of Active Short-Term Retrieval on Episodic Memory.

    Science.gov (United States)

    Marin, Bianca M; VanHaerents, Stephen A; Voss, Joel L; Bridge, Donna J

    2018-01-01

    Dorsolateral prefrontal cortex (DLPFC) is thought to organize items in working memory and this organizational role may also influence long-term memory. To causally test this hypothesized role of DLPFC in long-term memory formation, we used θ-burst noninvasive stimulation (TBS) to modulate DLPFC involvement in a memory task that assessed the influence of active short-term retrieval on later memory. Human subjects viewed three objects on a grid and then either actively retrieved or passively restudied one object's location after a brief delay. Long-term memory for the other objects was assessed after a delay to evaluate the beneficial role of active short-term retrieval on subsequent memory for the entire set of object locations. We found that DLPFC TBS had no significant effects on short-term memory. In contrast, DLPFC TBS impaired long-term memory selectively in the active-retrieval condition but not in the passive-restudy condition. These findings are consistent with the hypothesized contribution of DLPFC to the organizational processes operative during active short-term retrieval that influence long-term memory, although other regions that were not stimulated could provide similar contributions. Notably, active-retrieval and passive-restudy conditions were intermixed, and therefore nonspecific influences of stimulation were well controlled. These results suggest that DLPFC is causally involved in organizing event information during active retrieval to support coherent long-term memory formation.

  18. Episodic Memory Retrieval Benefits from a Less Modular Brain Network Organization

    Science.gov (United States)

    2017-01-01

    Most complex cognitive tasks require the coordinated interplay of multiple brain networks, but the act of retrieving an episodic memory may place especially heavy demands for communication between the frontoparietal control network (FPCN) and the default mode network (DMN), two networks that do not strongly interact with one another in many task contexts. We applied graph theoretical analysis to task-related fMRI functional connectivity data from 20 human participants and found that global brain modularity—a measure of network segregation—is markedly reduced during episodic memory retrieval relative to closely matched analogical reasoning and visuospatial perception tasks. Individual differences in modularity were correlated with memory task performance, such that lower modularity levels were associated with a lower false alarm rate. Moreover, the FPCN and DMN showed significantly elevated coupling with each other during the memory task, which correlated with the global reduction in brain modularity. Both networks also strengthened their functional connectivity with the hippocampus during the memory task. Together, these results provide a novel demonstration that reduced modularity is conducive to effective episodic retrieval, which requires close collaboration between goal-directed control processes supported by the FPCN and internally oriented self-referential processing supported by the DMN. SIGNIFICANCE STATEMENT Modularity, an index of the degree to which nodes of a complex system are organized into discrete communities, has emerged as an important construct in the characterization of brain connectivity dynamics. We provide novel evidence that the modularity of the human brain is reduced when individuals engage in episodic memory retrieval, relative to other cognitive tasks, and that this state of lower modularity is associated with improved memory performance. We propose a neural systems mechanism for this finding where the nodes of the frontoparietal

  19. Pointing Verification Method for Spaceborne Lidars

    Directory of Open Access Journals (Sweden)

    Axel Amediek

    2017-01-01

    Full Text Available High precision acquisition of atmospheric parameters from the air or space by means of lidar requires accurate knowledge of laser pointing. Discrepancies between the assumed and actual pointing can introduce large errors due to the Doppler effect or a wrongly assumed air pressure at ground level. In this paper, a method for precisely quantifying these discrepancies for airborne and spaceborne lidar systems is presented. The method is based on the comparison of ground elevations derived from the lidar ranging data with high-resolution topography data obtained from a digital elevation model and allows for the derivation of the lateral and longitudinal deviation of the laser beam propagation direction. The applicability of the technique is demonstrated by using experimental data from an airborne lidar system, confirming that geo-referencing of the lidar ground spot trace with an uncertainty of less than 10 m with respect to the used digital elevation model (DEM can be obtained.

  20. Rotator side chains trigger cooperative transition for shape and function memory effect in organic semiconductors.

    Science.gov (United States)

    Chung, Hyunjoong; Dudenko, Dmytro; Zhang, Fengjiao; D'Avino, Gabriele; Ruzié, Christian; Richard, Audrey; Schweicher, Guillaume; Cornil, Jérôme; Beljonne, David; Geerts, Yves; Diao, Ying

    2018-01-18

    Martensitic transition is a solid-state phase transition involving cooperative movement of atoms, mostly studied in metallurgy. The main characteristics are low transition barrier, ultrafast kinetics, and structural reversibility. They are rarely observed in molecular crystals, and hence the origin and mechanism are largely unexplored. Here we report the discovery of martensitic transition in single crystals of two different organic semiconductors. In situ microscopy, single-crystal X-ray diffraction, Raman and nuclear magnetic resonance spectroscopy, and molecular simulations combined indicate that the rotating bulky side chains trigger cooperative transition. Cooperativity enables shape memory effect in single crystals and function memory effect in thin film transistors. We establish a molecular design rule to trigger martensitic transition in organic semiconductors, showing promise for designing next-generation smart multifunctional materials.

  1. Memory

    OpenAIRE

    Wager, Nadia

    2017-01-01

    This chapter will explore a response to traumatic victimisation which has divided the opinions of psychologists at an exponential rate. We will be examining amnesia for memories of childhood sexual abuse and the potential to recover these memories in adulthood. Whilst this phenomenon is generally accepted in clinical circles, it is seen as highly contentious amongst research psychologists, particularly experimental cognitive psychologists. The chapter will begin with a real case study of a wo...

  2. Plausible carrier transport model in organic-inorganic hybrid perovskite resistive memory devices

    Directory of Open Access Journals (Sweden)

    Nayoung Park

    2018-04-01

    Full Text Available We demonstrate thermally assisted hopping (TAH as an appropriate carrier transport model for CH3NH3PbI3 resistive memories. Organic semiconductors, including organic-inorganic hybrid perovskites, have been previously speculated to follow the space-charge-limited conduction (SCLC model. However, the SCLC model cannot reproduce the temperature dependence of experimental current-voltage curves. Instead, the TAH model with temperature-dependent trap densities and a constant trap level are demonstrated to well reproduce the experimental results.

  3. A bio-inspired memory device based on interfacing Physarum polycephalum with an organic semiconductor

    Directory of Open Access Journals (Sweden)

    Agostino Romeo

    2015-01-01

    Full Text Available The development of devices able to detect and record ion fluxes is a crucial point in order to understand the mechanisms that regulate communication and life of organisms. Here, we take advantage of the combined electronic and ionic conduction properties of a conducting polymer to develop a hybrid organic/living device with a three-terminal configuration, using the Physarum polycephalum Cell (PPC slime mould as a living bio-electrolyte. An over-oxidation process induces a conductivity switch in the polymer, due to the ionic flux taking place at the PPC/polymer interface. This behaviour endows a current-depending memory effect to the device.

  4. A bio-inspired memory device based on interfacing Physarum polycephalum with an organic semiconductor

    Energy Technology Data Exchange (ETDEWEB)

    Romeo, Agostino; Dimonte, Alice; Tarabella, Giuseppe; D’Angelo, Pasquale, E-mail: dangelo@imem.cnr.it, E-mail: iannotta@imem.cnr.it; Erokhin, Victor; Iannotta, Salvatore, E-mail: dangelo@imem.cnr.it, E-mail: iannotta@imem.cnr.it [IMEM-CNR, Institute of Materials for Electronics and Magnetism-National Research Council, Parma 43124 (Italy)

    2015-01-01

    The development of devices able to detect and record ion fluxes is a crucial point in order to understand the mechanisms that regulate communication and life of organisms. Here, we take advantage of the combined electronic and ionic conduction properties of a conducting polymer to develop a hybrid organic/living device with a three-terminal configuration, using the Physarum polycephalum Cell (PPC) slime mould as a living bio-electrolyte. An over-oxidation process induces a conductivity switch in the polymer, due to the ionic flux taking place at the PPC/polymer interface. This behaviour endows a current-depending memory effect to the device.

  5. Charge Carrier Transport Mechanism Based on Stable Low Voltage Organic Bistable Memory Device.

    Science.gov (United States)

    Ramana, V V; Moodley, M K; Kumar, A B V Kiran; Kannan, V

    2015-05-01

    A solution processed two terminal organic bistable memory device was fabricated utilizing films of polymethyl methacrylate PMMA/ZnO/PMMA on top of ITO coated glass. Electrical characterization of the device structure showed that the two terminal device exhibited favorable switching characteristics with an ON/OFF ratio greater than 1 x 10(4) when the voltage was swept between - 2 V and +3 V. The device maintained its state after removal of the bias voltage. The device did not show degradation after a 1-h retention test at 120 degrees C. The memory functionality was consistent even after fifty cycles of operation. The charge transport switching mechanism is discussed on the basis of carrier transport mechanism and our analysis of the data shows that the charge carrier trans- port mechanism of the device during the writing process can be explained by thermionic emission (TE) and space-charge-limited-current (SCLC) mechanism models while erasing process could be explained by the FN tunneling mechanism. This demonstration provides a class of memory devices with the potential for low-cost, low-power consumption applications, such as a digital memory cell.

  6. Towards an organization with a memory: exploring the organizational generation of adverse events in health care.

    Science.gov (United States)

    Smith, Denis; Toft, Brian

    2005-05-01

    The role of organizational factors in the generation of adverse events, and the manner in which such factors can also inhibit an organization's abilities to learn, have become important agenda items within health care. The government report 'An organization with a memory' highlighted many of the problems facing health care and suggested changes that need to be made if the sector is to learn effective lessons and prevent adverse events from occurring. This paper seeks to examine some of these organizational factors in more detail and suggests issues that managers need to consider as part of their wider strategies for the prevention and management of risk. The paper sets out five core elements that are held to be importance in shaping the manner in which the potential for risk is incubated within organizations. Although the paper focuses its attention on health care, the points made have validity across the public sector and into private sector organizations.

  7. Direct observation of conductive filament formation in Alq3 based organic resistive memories

    Energy Technology Data Exchange (ETDEWEB)

    Busby, Y., E-mail: yan.busby@unamur.be; Pireaux, J.-J. [Research Center in the Physics of Matter and Radiation (PMR), Laboratoire Interdisciplinaire de Spectroscopie Electronique (LISE), University of Namur, B-5000 Namur (Belgium); Nau, S.; Sax, S. [NanoTecCenter Weiz Forschungsgesellschaft mbH, Franz-Pichler Straße 32, A-8160 Weiz (Austria); List-Kratochvil, E. J. W. [NanoTecCenter Weiz Forschungsgesellschaft mbH, Franz-Pichler Straße 32, A-8160 Weiz (Austria); Institute of Solid State Physics, Graz University of Technology, A-8010 Graz (Austria); Novak, J.; Banerjee, R.; Schreiber, F. [Institute of Applied Physics, Eberhard-Karls-Universität Tübingen, D-72076 Tübingen (Germany)

    2015-08-21

    This work explores resistive switching mechanisms in non-volatile organic memory devices based on tris(8-hydroxyquinolie)aluminum (Alq{sub 3}). Advanced characterization tools are applied to investigate metal diffusion in ITO/Alq{sub 3}/Ag memory device stacks leading to conductive filament formation. The morphology of Alq{sub 3}/Ag layers as a function of the metal evaporation conditions is studied by X-ray reflectivity, while depth profile analysis with X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry is applied to characterize operational memory elements displaying reliable bistable current-voltage characteristics. 3D images of the distribution of silver inside the organic layer clearly point towards the existence of conductive filaments and allow for the identification of the initial filament formation and inactivation mechanisms during switching of the device. Initial filament formation is suggested to be driven by field assisted diffusion of silver from abundant structures formed during the top electrode evaporation, whereas thermochemical effects lead to local filament inactivation.

  8. Physical implication of transition voltage in organic nano-floating-gate nonvolatile memories

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shun; Gao, Xu, E-mail: wangsd@suda.edu.cn, E-mail: gaoxu@suda.edu.cn; Zhong, Ya-Nan; Zhang, Zhong-Da; Xu, Jian-Long; Wang, Sui-Dong, E-mail: wangsd@suda.edu.cn, E-mail: gaoxu@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou, Jiangsu 215123 (China)

    2016-07-11

    High-performance pentacene-based organic field-effect transistor nonvolatile memories, using polystyrene as a tunneling dielectric and Au nanoparticles as a nano-floating-gate, show parallelogram-like transfer characteristics with a featured transition point. The transition voltage at the transition point corresponds to a threshold electric field in the tunneling dielectric, over which stored electrons in the nano-floating-gate will start to leak out. The transition voltage can be modulated depending on the bias configuration and device structure. For p-type active layers, optimized transition voltage should be on the negative side of but close to the reading voltage, which can simultaneously achieve a high ON/OFF ratio and good memory retention.

  9. Organic bistable memory devices based on MoO3 nanoparticle embedded Alq3 structures

    Science.gov (United States)

    Abhijith, T.; Kumar, T. V. Arun; Reddy, V. S.

    2017-03-01

    Organic bistable memory devices were fabricated by embedding a thin layer of molybdenum trioxide (MoO3) between two tris-(8-hydroxyquinoline)aluminum (Alq3) layers. The device exhibited excellent switching characteristics with an ON/OFF current ratio of 1.15 × 103 at a read voltage of 1 V. The device showed repeatable write-erase capability and good stability in both the conductance states. These conductance states are non-volatile in nature and can be obtained by applying appropriate voltage pulses. The effect of MoO3 layer thickness and its location in the Alq3 matrix on characteristics of the memory device was investigated. The field emission scanning electron microscopy (FE-SEM) images of the MoO3 layer revealed the presence of isolated nanoparticles. Based on the experimental results, a mechanism has been proposed for explaining the conductance switching of fabricated devices.

  10. Conjugated donor-acceptor-acceptor (D-A-A) molecule for organic nonvolatile resistor memory.

    Science.gov (United States)

    Dong, Lei; Li, Guangwu; Yu, An-Dih; Bo, Zhishan; Liu, Cheng-Liang; Chen, Wen-Chang

    2014-12-01

    A new donor-acceptor-acceptor (D-A-A) type of conjugated molecule, N-(4-(N',N'-diphenyl)phenylamine)-4-(4'-(2,2-dicyanovinyl)phenyl) naphthalene-1,8-dicarboxylic monoimide (TPA-NI-DCN), consisting of triphenylamine (TPA) donors and naphthalimide (NI)/dicyanovinylene (DCN) acceptors was synthesized and characterized. In conjunction with previously reported D-A based materials, the additional DCN moiety attached as end group in the D-A-A configuration can result in a stable charge transfer (CT) and charge-separated state to maintain the ON state current. The vacuum-deposited TPA-NI-DCN device fabricated as an active memory layer was demonstrated to exhibit write-once-read-many (WORM) switching characteristics of organic nonvolatile memory due to the strong polarity of the TPA-NI-DCN moiety. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Flexible and twistable non-volatile memory cell array with all-organic one diode-one resistor architecture.

    Science.gov (United States)

    Ji, Yongsung; Zeigler, David F; Lee, Dong Su; Choi, Hyejung; Jen, Alex K-Y; Ko, Heung Cho; Kim, Tae-Wook

    2013-01-01

    Flexible organic memory devices are one of the integral components for future flexible organic electronics. However, high-density all-organic memory cell arrays on malleable substrates without cross-talk have not been demonstrated because of difficulties in their fabrication and relatively poor performances to date. Here we demonstrate the first flexible all-organic 64-bit memory cell array possessing one diode-one resistor architectures. Our all-organic one diode-one resistor cell exhibits excellent rewritable switching characteristics, even during and after harsh physical stresses. The write-read-erase-read output sequence of the cells perfectly correspond to the external pulse signal regardless of substrate deformation. The one diode-one resistor cell array is clearly addressed at the specified cells and encoded letters based on the standard ASCII character code. Our study on integrated organic memory cell arrays suggests that the all-organic one diode-one resistor cell architecture is suitable for high-density flexible organic memory applications in the future.

  12. Memories.

    Science.gov (United States)

    Brand, Judith, Ed.

    1998-01-01

    This theme issue of the journal "Exploring" covers the topic of "memories" and describes an exhibition at San Francisco's Exploratorium that ran from May 22, 1998 through January 1999 and that contained over 40 hands-on exhibits, demonstrations, artworks, images, sounds, smells, and tastes that demonstrated and depicted the biological,…

  13. Episodic Memory Retrieval Benefits from a Less Modular Brain Network Organization.

    Science.gov (United States)

    Westphal, Andrew J; Wang, Siliang; Rissman, Jesse

    2017-03-29

    Most complex cognitive tasks require the coordinated interplay of multiple brain networks, but the act of retrieving an episodic memory may place especially heavy demands for communication between the frontoparietal control network (FPCN) and the default mode network (DMN), two networks that do not strongly interact with one another in many task contexts. We applied graph theoretical analysis to task-related fMRI functional connectivity data from 20 human participants and found that global brain modularity-a measure of network segregation-is markedly reduced during episodic memory retrieval relative to closely matched analogical reasoning and visuospatial perception tasks. Individual differences in modularity were correlated with memory task performance, such that lower modularity levels were associated with a lower false alarm rate. Moreover, the FPCN and DMN showed significantly elevated coupling with each other during the memory task, which correlated with the global reduction in brain modularity. Both networks also strengthened their functional connectivity with the hippocampus during the memory task. Together, these results provide a novel demonstration that reduced modularity is conducive to effective episodic retrieval, which requires close collaboration between goal-directed control processes supported by the FPCN and internally oriented self-referential processing supported by the DMN. SIGNIFICANCE STATEMENT Modularity, an index of the degree to which nodes of a complex system are organized into discrete communities, has emerged as an important construct in the characterization of brain connectivity dynamics. We provide novel evidence that the modularity of the human brain is reduced when individuals engage in episodic memory retrieval, relative to other cognitive tasks, and that this state of lower modularity is associated with improved memory performance. We propose a neural systems mechanism for this finding where the nodes of the frontoparietal control

  14. Dall-Null tester for spaceborne applications

    Science.gov (United States)

    Wingler, R. L.

    1984-12-01

    This is a study to design a self correcting primary mirror system for a space telescope. The design is centered around a Dall-Null tester (a Foucault knife-edge tester with compensating lens). An indepth study of the theory of the Foucault test from Foucault's original publications to current work is presented. Also short comings of the diffraction approach are shown. The findings of a simple experiment showed the way to the correct explanation as to the workings of the test. Based on this new explanation, a computer program to find the error in the surface of the mirror from the irradiance pattern provided by the Dall-Null tester was developed. The computer program with a sample run is included in the appendixes A and B. The basic design of an adaptive optic system for a spaceborne application is also presented in the paper. This design has the desired quality of being able to correct the mirror while the telescope is in use. The equations being independent of wavelength allows for the design to be applied to systems working outside of the visible spectrum as well as the systems working in the visible.

  15. A complementary switching mechanism for organic memory devices to regulate the conductance of binary states

    Science.gov (United States)

    Vyas, Giriraj; Dagar, Parveen; Sahu, Satyajit

    2016-06-01

    We have fabricated an organic non-volatile memory device wherein the ON/OFF current ratio has been controlled by varying the concentration of a small organic molecule, 2,3-Dichloro-5,6-dicyano-p-benzoquinone (DDQ), in an insulating matrix of a polymer Poly(4-vinylphenol) (PVP). A maximum ON-OFF ratio of 106 is obtained when the concentration of DDQ is half or 10 wt. % of PVP. In this process, the switching direction for the devices has also been altered, indicating the disparity in conduction mechanism. Conduction due to metal filament formation through the active material and the voltage dependent conformational change of the organic molecule seem to be the motivation behind the gradual change in the switching direction.

  16. Effect of halide-mixing on the switching behaviors of organic-inorganic hybrid perovskite memory

    Science.gov (United States)

    Hwang, Bohee; Gu, Chungwan; Lee, Donghwa; Lee, Jang-Sik

    2017-03-01

    Mixed halide perovskite materials are actively researched for solar cells with high efficiency. Their hysteresis which originates from the movement of defects make perovskite a candidate for resistive switching memory devices. We demonstrate the resistive switching device based on mixed-halide organic-inorganic hybrid perovskite CH3NH3PbI3-xBrx (x = 0, 1, 2, 3). Solvent engineering is used to deposit the homogeneous CH3NH3PbI3-xBrx layer on the indium-tin oxide-coated glass substrates. The memory device based on CH3NH3PbI3-xBrx exhibits write endurance and long retention, which indicate reproducible and reliable memory properties. According to the increase in Br contents in CH3NH3PbI3-xBrx the set electric field required to make the device from low resistance state to high resistance state decreases. This result is in accord with the theoretical calculation of migration barriers, that is the barrier to ionic migration in perovskites is found to be lower for Br- (0.23 eV) than for I- (0.29-0.30 eV). The resistive switching may be the result of halide vacancy defects and formation of conductive filaments under electric field in the mixed perovskite layer. It is observed that enhancement in operating voltage can be achieved by controlling the halide contents in the film.

  17. The objects of visuospatial short-term memory: Perceptual organization and change detection.

    Science.gov (United States)

    Nikolova, Atanaska; Macken, Bill

    2016-01-01

    We used a colour change-detection paradigm where participants were required to remember colours of six equally spaced circles. Items were superimposed on a background so as to perceptually group them within (a) an intact ring-shaped object, (b) a physically segmented but perceptually completed ring-shaped object, or (c) a corresponding background segmented into three arc-shaped objects. A nonpredictive cue at the location of one of the circles was followed by the memory items, which in turn were followed by a test display containing a probe indicating the circle to be judged same/different. Reaction times for correct responses revealed a same-object advantage; correct responses were faster to probes on the same object as the cue than to equidistant probes on a segmented object. This same-object advantage was identical for physically and perceptually completed objects, but was only evident in reaction times, and not in accuracy measures. Not only, therefore, is it important to consider object-level perceptual organization of stimulus elements when assessing the influence of a range of factors (e.g., number and complexity of elements) in visuospatial short-term memory, but a more detailed picture of the structure of information in memory may be revealed by measuring speed as well as accuracy.

  18. Organic non-volatile memories from ferroelectric phase-separated blends

    Science.gov (United States)

    Asadi, Kamal; de Leeuw, Dago M.; de Boer, Bert; Blom, Paul W. M.

    2008-07-01

    New non-volatile memories are being investigated to keep up with the organic-electronics road map. Ferroelectric polarization is an attractive physical property as the mechanism for non-volatile switching, because the two polarizations can be used as two binary levels. However, in ferroelectric capacitors the read-out of the polarization charge is destructive. The functionality of the targeted memory should be based on resistive switching. In inorganic ferroelectrics conductivity and ferroelectricity cannot be tuned independently. The challenge is to develop a storage medium in which the favourable properties of ferroelectrics such as bistability and non-volatility can be combined with the beneficial properties provided by semiconductors such as conductivity and rectification. Here we present an integrated solution by blending semiconducting and ferroelectric polymers into phase-separated networks. The polarization field of the ferroelectric modulates the injection barrier at the semiconductor-metal contact. The combination of ferroelectric bistability with (semi)conductivity and rectification allows for solution-processed non-volatile memory arrays with a simple cross-bar architecture that can be read out non-destructively. The concept of an electrically tunable injection barrier as presented here is general and can be applied to other electronic devices such as light-emitting diodes with an integrated on/off switch.

  19. Surface-type nonvolatile electric memory elements based on organic-on-organic CuPc-H2Pc heterojunction

    International Nuclear Information System (INIS)

    Karimov, Khasan S.; Muqeet Rehman, M.; Zameer Abbas, S.; Ahmad, Zubair; Touati, Farid; Mahroof-Tahir, M.

    2015-01-01

    A novel surface-type nonvolatile electric memory elements based on organic semiconductors CuPc and H 2 Pc are fabricated by vacuum deposition of the CuPc and H 2 Pc films on preliminary deposited metallic (Ag and Cu) electrodes. The gap between Ag and Cu electrodes is 30–40 μm. For the current–voltage (I–V) characteristics the memory effect, switching effect, and negative differential resistance regions are observed. The switching mechanism is attributed to the electric-field-induced charge transfer. As a result the device switches from a low to a high-conductivity state and then back to a low conductivity state if the opposite polarity voltage is applied. The ratio of resistance at the high resistance state to that at the low resistance state is equal to 120–150. Under the switching condition, the electric current increases ∼ 80–100 times. A comparison between the forward and reverse I–V characteristics shows the presence of rectifying behavior. (paper)

  20. Semantic Memory Organization in Japanese Patients With Schizophrenia Examined With Category Fluency

    Directory of Open Access Journals (Sweden)

    Chika Sumiyoshi

    2018-03-01

    Full Text Available BackgroundDisorganization of semantic memory in patients with schizophrenia has been studied by referring to their category fluency performance. Recently, data-mining techniques such as singular value decomposition (SVD analysis have been reported to be effective in elucidating the latent semantic memory structure in patients with schizophrenia. The aim of this study is to investigate semantic memory organization in patients with schizophrenia using a novel method based on data-mining approach.MethodCategory fluency data were collected from 181 patients with schizophrenia and 335 healthy controls at the Department of Psychiatry, Osaka University. The 20 most frequently reported animals were chosen for SVD analysis. In the two-dimensional (2D solution, item vectors (i.e., animal names were plotted in the 2D space of each group. In the six-dimensional (6D solution, inter-item similarities (i.e., cosines were calculated among items. Cosine charts were also created for the six most frequent items to show the similarities to other animal items.ResultsIn the 2D spatial representation, the six most frequent items were grouped in the same clusters (i.e., dog, cat as pet cluster, lion, tiger as wild/carnivorous cluster, and elephant, giraffe as wild/herbivorous cluster for patients and healthy adults. As for 6D spatial cosines, the correlations (Pearson’s r between 17 items commonly generated in the two groups were moderately high. However, cosine charts created for the three pairs from the six most frequent animals (dog–cat, lion–tiger, elephant–giraffe showed that pair-wise similarities between other animals were less salient in patients with schizophrenia.DiscussionSemantic memory organization in patients with schizophrenia, revealed by SVD analysis, did not appear to be seriously impaired in the 2D space representation, maintaining a clustering structure similar to that in healthy controls for common animals. However, the coherence of those

  1. High‐Performance Nonvolatile Organic Field‐Effect Transistor Memory Based on Organic Semiconductor Heterostructures of Pentacene/P13/Pentacene as Both Charge Transport and Trapping Layers

    Science.gov (United States)

    Li, Wen; Guo, Fengning; Ling, Haifeng; Zhang, Peng; Wang, Laiyuan; Wu, Dequn

    2017-01-01

    Nonvolatile organic field‐effect transistor (OFET) memory devices based on pentacene/N,N′‐ditridecylperylene‐3,4,9,10‐tetracarboxylic diimide (P13)/pentacene trilayer organic heterostructures have been proposed. The discontinuous n‐type P13 embedded in p‐type pentacene layers can not only provide electrons in the semiconductor layer that facilitates electron trapping process; it also works as charge trapping sites, which is attributed to the quantum well‐like pentacene/P13/pentacene organic heterostructures. The synergistic effects of charge trapping in the discontinuous P13 and the charge‐trapping property of the poly(4‐vinylphenol) (PVP) layer remarkably improve the memory performance. In addition, the trilayer organic heterostructures have also been successfully applied to multilevel and flexible nonvolatile memory devices. The results provide a novel design strategy to achieve high‐performance nonvolatile OFET memory devices and allow potential applications for different combinations of various organic semiconductor materials in OFET memory. PMID:28852619

  2. Concept of rewritable organic ferroelectric random access memory in two lateral transistors-in-one cell architecture

    International Nuclear Information System (INIS)

    Kim, Min-Hoi; Lee, Gyu Jeong; Keum, Chang-Min; Lee, Sin-Doo

    2014-01-01

    We propose a concept of rewritable ferroelectric random access memory (RAM) with two lateral organic transistors-in-one cell architecture. Lateral integration of a paraelectric organic field-effect transistor (OFET), being a selection transistor, and a ferroelectric OFET as a memory transistor is realized using a paraelectric depolarizing layer (PDL) which is patterned on a ferroelectric insulator by transfer-printing. For the selection transistor, the key roles of the PDL are to reduce the dipolar strength and the surface roughness of the gate insulator, leading to the low memory on–off ratio and the high switching on–off current ratio. A new driving scheme preventing the crosstalk between adjacent memory cells is also demonstrated for the rewritable operation of the ferroelectric RAM. (paper)

  3. Boost Up Carrier Mobility for Ferroelectric Organic Transistor Memory via Buffering Interfacial Polarization Fluctuation

    Science.gov (United States)

    Sun, Huabin; Wang, Qijing; Li, Yun; Lin, Yen-Fu; Wang, Yu; Yin, Yao; Xu, Yong; Liu, Chuan; Tsukagoshi, Kazuhito; Pan, Lijia; Wang, Xizhang; Hu, Zheng; Shi, Yi

    2014-11-01

    Ferroelectric organic field-effect transistors (Fe-OFETs) have been attractive for a variety of non-volatile memory device applications. One of the critical issues of Fe-OFETs is the improvement of carrier mobility in semiconducting channels. In this article, we propose a novel interfacial buffering method that inserts an ultrathin poly(methyl methacrylate) (PMMA) between ferroelectric polymer and organic semiconductor layers. A high field-effect mobility (μFET) up to 4.6 cm2 V-1 s-1 is obtained. Subsequently, the programming process in our Fe-OFETs is mainly dominated by the switching between two ferroelectric polarizations rather than by the mobility-determined charge accumulation at the channel. Thus, the ``reading'' and ``programming'' speeds are significantly improved. Investigations show that the polarization fluctuation at semiconductor/insulator interfaces, which affect the charge transport in conducting channels, can be suppressed effectively using our method.

  4. Self-organized titanium oxide nano-channels for resistive memory application

    Energy Technology Data Exchange (ETDEWEB)

    Barman, A.; Saini, C. P.; Dhar, S.; Kanjilal, A., E-mail: aloke.kanjilal@snu.edu.in [Department of Physics, School of Natural Sciences, Shiv Nadar University, NH-91, Tehsil Dadri, Gautam Buddha Nagar, Uttar Pradesh 201 314 (India); Sarkar, P. [Department of Physics, National Institute of Technology, Silchar, Assam 788 010 (India); Satpati, B.; Bhattacharyya, S. R. [Surface Physics and Material Science Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700 064 (India); Kabiraj, D.; Kanjilal, D. [Inter-University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110 067 (India)

    2015-12-14

    Towards developing next generation scalable TiO{sub 2}-based resistive switching (RS) memory devices, the efficacy of 50 keV Ar{sup +}-ion irradiation to achieve self-organized nano-channel based structures at a threshold fluence of 5 × 10{sup 16} ions/cm{sup 2} at ambient temperature is presented. Although x-ray diffraction results suggest the amorphization of as-grown TiO{sub 2} layers, detailed transmission electron microscopy study reveals fluence-dependent evolution of voids and eventual formation of self-organized nano-channels between them. Moreover, gradual increase of TiO/Ti{sub 2}O{sub 3} in the near surface region, as monitored by x-ray photoelectron spectroscopy, establishes the upsurge in oxygen deficient centers. The impact of structural and chemical modification on local RS behavior has also been investigated by current-voltage measurements in conductive atomic force microscopy, while memory application is manifested by fabricating Pt/TiO{sub 2}/Pt/Ti/SiO{sub 2}/Si devices. Finally, the underlying mechanism of our experimental results has been analyzed and discussed in the light of oxygen vacancy migration through nano-channels.

  5. An Adaptive Ship Detection Scheme for Spaceborne SAR Imagery

    Directory of Open Access Journals (Sweden)

    Xiangguang Leng

    2016-08-01

    Full Text Available With the rapid development of spaceborne synthetic aperture radar (SAR and the increasing need of ship detection, research on adaptive ship detection in spaceborne SAR imagery is of great importance. Focusing on practical problems of ship detection, this paper presents a highly adaptive ship detection scheme for spaceborne SAR imagery. It is able to process a wide range of sensors, imaging modes and resolutions. Two main stages are identified in this paper, namely: ship candidate detection and ship discrimination. Firstly, this paper proposes an adaptive land masking method using ship size and pixel size. Secondly, taking into account the imaging mode, incidence angle, and polarization channel of SAR imagery, it implements adaptive ship candidate detection in spaceborne SAR imagery by applying different strategies to different resolution SAR images. Finally, aiming at different types of typical false alarms, this paper proposes a comprehensive ship discrimination method in spaceborne SAR imagery based on confidence level and complexity analysis. Experimental results based on RADARSAT-1, RADARSAT-2, TerraSAR-X, RS-1, and RS-3 images demonstrate that the adaptive scheme proposed in this paper is able to detect ship targets in a fast, efficient and robust way.

  6. A Naturalistic Assessment of the Organization of Children's Memories Predicts Cognitive Functioning and Reading Ability

    Science.gov (United States)

    Mota, Natália Bezerra; Weissheimer, Janaína; Madruga, Beatriz; Adamy, Nery; Bunge, Silvia A.; Copelli, Mauro; Ribeiro, Sidarta

    2016-01-01

    To explore the relationship between memory and early school performance, we used graph theory to investigate memory reports from 76 children aged 6-8 years. The reports comprised autobiographical memories of events days to years past, and memories of novel images reported immediately after encoding. We also measured intelligence quotient (IQ) and…

  7. Better Organic Ternary Memory Performance through Self-Assembled Alkyltrichlorosilane Monolayers on Indium Tin Oxide (ITO) Surfaces.

    Science.gov (United States)

    Hou, Xiang; Cheng, Xue-Feng; Zhou, Jin; He, Jing-Hui; Xu, Qing-Feng; Li, Hua; Li, Na-Jun; Chen, Dong-Yun; Lu, Jian-Mei

    2017-11-16

    Recently, surface engineering of the indium tin oxide (ITO) electrode of sandwich-like organic electric memory devices was found to effectively improve their memory performances. However, there are few methods to modify the ITO substrates. In this paper, we have successfully prepared alkyltrichlorosilane self-assembled monolayers (SAMs) on ITO substrates, and resistive random access memory devices are fabricated on these surfaces. Compared to the unmodified ITO substrates, organic molecules (i.e., 2-((4-butylphenyl)amino)-4-((4-butylphenyl)iminio)-3-oxocyclobut-1-en-1-olate, SA-Bu) grown on these SAM-modified ITO substrates have rougher surface morphologies but a smaller mosaicity. The organic layer on the SAM-modified ITO further aged to eliminate the crystalline phase diversity. In consequence, the ternary memory yields are effectively improved to approximately 40-47 %. Our results suggest that the insertion of alkyltrichlorosilane self-assembled monolayers could be an efficient method to improve the performance of organic memory devices. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Optical registration of spaceborne low light remote sensing camera

    Science.gov (United States)

    Li, Chong-yang; Hao, Yan-hui; Xu, Peng-mei; Wang, Dong-jie; Ma, Li-na; Zhao, Ying-long

    2018-02-01

    For the high precision requirement of spaceborne low light remote sensing camera optical registration, optical registration of dual channel for CCD and EMCCD is achieved by the high magnification optical registration system. System integration optical registration and accuracy of optical registration scheme for spaceborne low light remote sensing camera with short focal depth and wide field of view is proposed in this paper. It also includes analysis of parallel misalignment of CCD and accuracy of optical registration. Actual registration results show that imaging clearly, MTF and accuracy of optical registration meet requirements, it provide important guarantee to get high quality image data in orbit.

  9. Towards a functional organization of episodic memory in the medial temporal lobe.

    Science.gov (United States)

    Eichenbaum, Howard; Sauvage, Magdalena; Fortin, Norbert; Komorowski, Robert; Lipton, Paul

    2012-08-01

    Here we describe a model of medial temporal lobe organization in which parallel "what" and "where" processing streams converge within the hippocampus to represent events in the spatio-temporal context in which they occurred; this circuitry also mediates the retrieval of context from event cues and vice versa, which are prototypes of episodic recall. Evidence from studies in animals are reviewed in support of this model, including experiments that distinguish characteristics of episodic recollection from familiarity, neuropsychological and recording studies that have identified a key role for the hippocampus in recollection and in associating events with the context in which they occurred, and distinct roles for parahippocampal region areas in separate "what" and "where" information processing that contributes to recollective and episodic memory. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Nonvolatile organic write-once-read-many-times memory devices based on hexadecafluoro-copper-phthalocyanine

    Science.gov (United States)

    Wang, Lidan; Su, Zisheng; Wang, Cheng

    2012-05-01

    Nonvolatile organic write-once-read-many-times memory device was demonstrated based on hexadecafluoro-copper-phthalocyanine (F16CuPc) single layer sandwiched between indium tin oxide (ITO) anode and Al cathode. The as fabricated device remains in ON state and it can be tuned to OFF state by applying a reverse bias. The ON/OFF current ratio of the device can reach up to 2.3 × 103. Simultaneously, the device shows long-term storage stability and long retention time in air. The ON/OFF transition is attributed to the formation and destruction of the interfacial dipole layer in the ITO/F16CuPc interface, and such a mechanism is different from previously reported ones.

  11. Crossover from Super- to Subdiffusive Motion and Memory Effects in Crystalline Organic Semiconductors

    Science.gov (United States)

    De Filippis, G.; Cataudella, V.; Mishchenko, A. S.; Nagaosa, N.; Fierro, A.; de Candia, A.

    2015-02-01

    The transport properties at finite temperature of crystalline organic semiconductors are investigated, within the Su-Schrieffer-Heeger model, by combining an exact diagonalization technique, Monte Carlo approaches, and a maximum entropy method. The temperature-dependent mobility data measured in single crystals of rubrene are successfully reproduced: a crossover from super- to subdiffusive motion occurs in the range 150 ≤T ≤200 K , where the mean free path becomes of the order of the lattice parameter and strong memory effects start to appear. We provide an effective model, which can successfully explain features of the absorption spectra at low frequencies. The observed response to slowly varying electric field is interpreted by means of a simple model where the interaction between the charge carrier and lattice polarization modes is simulated by a harmonic interaction between a fictitious particle and an electron embedded in a viscous fluid.

  12. Memory versus logic: two models of organizing information and their influences on web retrieval strategies

    Directory of Open Access Journals (Sweden)

    Teresa Numerico

    2008-07-01

    Full Text Available We can find the first anticipation of the World Wide Web hypertextual structure in Bush paper of 1945, where he described a “selection” and storage machine called the Memex, capable of keeping the useful information of a user and connecting it to other relevant material present in the machine or added by other users. We will argue that Vannevar Bush, who conceived this type of machine, did it because its involvement with analogical devices. During the 1930s, in fact, he invented and built the Differential Analyzer, a powerful analogue machine, used to calculate various relevant mathematical functions. The model of the Memex is not the digital one, because it relies on another form of data representation that emulates more the procedures of memory than the attitude of the logic used by the intellect. Memory seems to select and arrange information according to association strategies, i.e., using analogies and connections that are very often arbitrary, sometimes even chaotic and completely subjective. The organization of information and the knowledge creation process suggested by logic and symbolic formal representation of data is deeply different from the former one, though the logic approach is at the core of the birth of computer science (i.e., the Turing Machine and the Von Neumann Machine. We will discuss the issues raised by these two “visions” of information management and the influences of the philosophical tradition of the theory of knowledge on the hypertextual organization of content. We will also analyze all the consequences of these different attitudes with respect to information retrieval techniques in a hypertextual environment, as the web. Our position is that it necessary to take into accounts the nature and the dynamic social topology of the network when we choose information retrieval methods for the network; otherwise, we risk creating a misleading service for the end user of web search tools (i.e., search engines.

  13. Lightweight high-performance 1-4 meter class spaceborne mirrors: emerging technology for demanding spaceborne requirements

    Science.gov (United States)

    Hull, Tony; Hartmann, Peter; Clarkson, Andrew R.; Barentine, John M.; Jedamzik, Ralf; Westerhoff, Thomas

    2010-07-01

    Pending critical spaceborne requirements, including coronagraphic detection of exoplanets, require exceptionally smooth mirror surfaces, aggressive lightweighting, and low-risk cost-effective optical manufacturing methods. Simultaneous development at Schott for production of aggressively lightweighted (>90%) Zerodur® mirror blanks, and at L-3 Brashear for producing ultra-smooth surfaces on Zerodur®, will be described. New L-3 techniques for large-mirror optical fabrication include Computer Controlled Optical Surfacing (CCOS) pioneered at L-3 Tinsley, and the world's largest MRF machine in place at L-3 Brashear. We propose that exceptional mirrors for the most critical spaceborne applications can now be produced with the technologies described.

  14. Enhancing memory performance after organic brain disease relies on retrieval processes rather than encoding or consolidation

    NARCIS (Netherlands)

    Hildebrandt, H.; Gehrmann, A.; Mödden, C.; Eling, P.A.T.M.

    2011-01-01

    Neuropsychological rehabilitation of memory performance is still a controversial topic, and rehabilitation studies have not analyzed to which stage of memory processing (encoding, consolidation, or retrieval) enhancement may be attributed. We first examined the efficacy of a computer training

  15. Development in the Organization of Episodic Memories in Middle Childhood and Adolescence

    OpenAIRE

    Yan eChen; Helena Margaret McAnally; Elaine eReese

    2013-01-01

    The basic elements of autobiographical or episodic memory are established in early childhood, although the exact age at which memories gain episodic status is still under contention. The self-memory system proposed that adults use “lifetime periods” to group episodic memories together into chapters of the life story – an evolving and internalized account of significant life events that are self-defining. Two studies examined at what point in development children or adolescents begin to take a...

  16. Memory effect driven emissions of persistent organic pollutants from industrial thermal processes, their implications and management: a review.

    Science.gov (United States)

    Trivedi, Jitendra; Majumdar, Deepanjan

    2013-04-15

    Memory effect is delayed emission of certain persistent organic pollutants (POPs). Many of the POP compounds viz. polycyclic aromatic hydrocarbons (PAHs), polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF) get trapped in the particulate phase deposited in the flue transfer lines and air pollution control systems (equivalent to storage in the memory of a system) and released subsequently. Memory effect driven emission is a combination of real time emission and emission of stored compounds and so is not a true measure of actual real time emission. Memory effect is now realized to have existed for a long time but was not identified and understood until recently. Memory effect has several serious implications e.g. it wrongly depicts emission patterns of POPs; it makes compliance to stipulated emission standards difficult; it could lead to wrong calculations of emission factors and emission inventory estimates of a plant and leads to misinterpretation of efficacy of processes and air pollution control systems. Further, new PCDD/Fs may be formed in the trapped particulate phase via de novo synthesis and the new compounds may be emitted, thereby increasing total PCDD/F emissions, apart from altering the homologue pattern of PCDD/Fs in emissions. Memory effect could be minimized by judicious operational and management (O&M) procedures like optimizing combustion, minimizing unnecessary halts in operations, periodical cleaning of flue transfer lines, application of inhibitors etc. Copyright © 2013 Elsevier Ltd. All rights reserved.

  17. Organic ferroelectric memory devices with inkjet-printed polymer electrodes on flexible substrates

    KAUST Repository

    Bhansali, Unnat Sampatraj

    2013-05-01

    Drop-on-demand piezoelectric inkjet-printing technique has been used to fabricate a functional cross-bar array of all-organic ferroelectric memory devices. The polymer-ferroelectric-polymer device consists of a ferroelectric copolymer P(VDF-TrFE) film sandwiched between inkjet-patterned, continuous, orthogonal lines of PEDOT:PSS polymer as the bottom and top electrodes. These devices exhibit well-saturated hysteresis curves with a maximum remnant polarization (Pr) = 6.7 μC/cm2, coercive field (E c) = 55 MV/m and a peak capacitance density of 45 nF/cm2. Our polarization fatigue measurements show that these devices retain ∼100% and 45% of their initial Pr values after 103 and 10 5 stress cycles, respectively. The overall performance and polarization retention characteristics of these ferroelectric capacitors with inkjet-printed polymer electrodes are comparable to metal and spin-cast polymer electrodes suggesting their potential use in large-area flexible electronics. © 2013 Elsevier Ltd. All rights reserved.

  18. Ultrametricity and memory in a solvable model of self-organized criticality

    International Nuclear Information System (INIS)

    Boettcher, S.; Paczuski, M.

    1996-01-01

    Slowly driven dissipative systems may evolve to a critical state where long periods of apparent equilibrium are punctuated by intermittent avalanches of activity. We present a self-organized critical model of punctuated equilibrium behavior in the context of biological evolution, and solve it in the limit that the number of independent traits for each species diverges. We derive an exact equation of motion for the avalanche dynamics from the microscopic rules. In the continuum limit, avalanches propagate via a diffusion equation with a nonlocal, history dependent potential representing memory. This nonlocal potential gives rise to a non-Gaussian (fat) tail for the subdiffusive spreading of activity. The probability for the activity to spread beyond a distance r in time s decays as √(24/π)s -3/2 x 1/3 exp[-3/4x 1/3 ] for x=r 4 /s>1. The potential represents a hierarchy of time scales that is dynamically generated by the ultrametric structure of avalanches, which can be quantified in terms of open-quote open-quote backward close-quote close-quote avalanches. In addition, a number of other correlation functions characterizing the punctuated equilibrium dynamics are determined exactly

  19. How "mere" is the mere ownership effect in memory? Evidence for semantic organization processes.

    Science.gov (United States)

    Englert, Julia; Wentura, Dirk

    2016-11-01

    Memory is better for items arbitrarily assigned to the self than for items assigned to another person (mere ownership effect, MOE). In a series of six experiments, we investigated the role of semantic processes for the MOE. Following successful replication, we investigated whether the MOE was contingent upon semantic processing: For meaningless stimuli, there was no MOE. Testing for a potential role of semantic elaboration using meaningful stimuli in an encoding task without verbal labels, we found evidence of spontaneous semantic processing irrespective of self- or other-assignment. When semantic organization was manipulated, the MOE vanished if a semantic classification task was added to the self/other assignment but persisted for a perceptual classification task. Furthermore, we found greater clustering of self-assigned than of other-assigned items in free recall. Taken together, these results suggest that the MOE could be based on the organizational principle of a "me" versus "not-me" categorization. Copyright © 2016 Elsevier Inc. All rights reserved.

  20. Reasoning on the Self-Organizing Incremental Associative Memory for Online Robot Path Planning

    Science.gov (United States)

    Kawewong, Aram; Honda, Yutaro; Tsuboyama, Manabu; Hasegawa, Osamu

    Robot path-planning is one of the important issues in robotic navigation. This paper presents a novel robot path-planning approach based on the associative memory using Self-Organizing Incremental Neural Networks (SOINN). By the proposed method, an environment is first autonomously divided into a set of path-fragments by junctions. Each fragment is represented by a sequence of preliminarily generated common patterns (CPs). In an online manner, a robot regards the current path as the associative path-fragments, each connected by junctions. The reasoning technique is additionally proposed for decision making at each junction to speed up the exploration time. Distinct from other methods, our method does not ignore the important information about the regions between junctions (path-fragments). The resultant number of path-fragments is also less than other method. Evaluation is done via Webots physical 3D-simulated and real robot experiments, where only distance sensors are available. Results show that our method can represent the environment effectively; it enables the robot to solve the goal-oriented navigation problem in only one episode, which is actually less than that necessary for most of the Reinforcement Learning (RL) based methods. The running time is proved finite and scales well with the environment. The resultant number of path-fragments matches well to the environment.

  1. Organization principles in visual working memory: Evidence from sequential stimulus display.

    Science.gov (United States)

    Gao, Zaifeng; Gao, Qiyang; Tang, Ning; Shui, Rende; Shen, Mowei

    2016-01-01

    Although the mechanisms of visual working memory (VWM) have been studied extensively in recent years, the active property of VWM has received less attention. In the current study, we examined how VWM integrates sequentially presented stimuli by focusing on the role of Gestalt principles, which are important organizing principles in perceptual integration. We manipulated the level of Gestalt cues among three or four sequentially presented objects that were memorized. The Gestalt principle could not emerge unless all the objects appeared together. We distinguished two hypotheses: a perception-alike hypothesis and an encoding-specificity hypothesis. The former predicts that the Gestalt cue will play a role in information integration within VWM; the latter predicts that the Gestalt cue will not operate within VWM. In four experiments, we demonstrated that collinearity (Experiment 1) and closure (Experiment 2) cues significantly improved VWM performance, and this facilitation was not affected by the testing manner (Experiment 3) or by adding extra colors to the memorized objects (Experiment 4). Finally, we re-established the Gestalt cue benefit with similarity cues (Experiment 5). These findings together suggest that VWM realizes and uses potential Gestalt principles within the stored representations, supporting a perception-alike hypothesis. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. SPACE-BORNE LASER ALTIMETER GEOLOCATION ERROR ANALYSIS

    Directory of Open Access Journals (Sweden)

    Y. Wang

    2018-05-01

    Full Text Available This paper reviews the development of space-borne laser altimetry technology over the past 40 years. Taking the ICESAT satellite as an example, a rigorous space-borne laser altimeter geolocation model is studied, and an error propagation equation is derived. The influence of the main error sources, such as the platform positioning error, attitude measurement error, pointing angle measurement error and range measurement error, on the geolocation accuracy of the laser spot are analysed by simulated experiments. The reasons for the different influences on geolocation accuracy in different directions are discussed, and to satisfy the accuracy of the laser control point, a design index for each error source is put forward.

  3. Forward modeling of space-borne gravitational wave detectors

    International Nuclear Information System (INIS)

    Rubbo, Louis J.; Cornish, Neil J.; Poujade, Olivier

    2004-01-01

    Planning is underway for several space-borne gravitational wave observatories to be built in the next 10 to 20 years. Realistic and efficient forward modeling will play a key role in the design and operation of these observatories. Space-borne interferometric gravitational wave detectors operate very differently from their ground-based counterparts. Complex orbital motion, virtual interferometry, and finite size effects complicate the description of space-based systems, while nonlinear control systems complicate the description of ground-based systems. Here we explore the forward modeling of space-based gravitational wave detectors and introduce an adiabatic approximation to the detector response that significantly extends the range of the standard low frequency approximation. The adiabatic approximation will aid in the development of data analysis techniques, and improve the modeling of astrophysical parameter extraction

  4. A Probabilistic Clustering Theory of the Organization of Visual Short-Term Memory

    Science.gov (United States)

    Orhan, A. Emin; Jacobs, Robert A.

    2013-01-01

    Experimental evidence suggests that the content of a memory for even a simple display encoded in visual short-term memory (VSTM) can be very complex. VSTM uses organizational processes that make the representation of an item dependent on the feature values of all displayed items as well as on these items' representations. Here, we develop a…

  5. Crossbar memory array of organic bistable rectifying diodes for nonvolatile data storage

    NARCIS (Netherlands)

    Asadi, Kamal; Li, Mengyuan; Stingelin, Natalie; Blom, Paul W. M.; de Leeuw, Dago M.

    2010-01-01

    Cross-talk in memories using resistive switches in a cross-bar geometry can be prevented by integration of a rectifying diode. We present a functional cross bar memory array using a phase separated blend of a ferroelectric and a semiconducting polymer as storage medium. Each intersection acts

  6. Source analysis of spaceborne microwave radiometer interference over land

    Science.gov (United States)

    Guan, Li; Zhang, Sibo

    2016-03-01

    Satellite microwave thermal emissions mixed with signals from active sensors are referred to as radiofrequency interference (RFI). Based on Advanced Microwave Scanning Radiometer-Earth Observing System (AMSR-E) observations from June 1 to 16, 2011, RFI over Europe was identified and analyzed using the modified principal component analysis algorithm in this paper. The X band AMSR-E measurements in England and Italy are mostly affected by the stable, persistent, active microwave transmitters on the surface, while the RFI source of other European countries is the interference of the reflected geostationary TV satellite downlink signals to the measurements of spaceborne microwave radiometers. The locations and intensities of the RFI induced by the geostationary TV and communication satellites changed with time within the observed period. The observations of spaceborne microwave radiometers in ascending portions of orbits are usually interfered with over European land, while no RFI was detected in descending passes. The RFI locations and intensities from the reflection of downlink radiation are highly dependent upon the relative geometry between the geostationary satellite and the measuring passive sensor. Only these fields of view of a spaceborne instrument whose scan azimuths are close to the azimuth relative to the geostationary satellite are likely to be affected by RFI.

  7. Unipolar resistive switching in metal oxide/organic semiconductor non-volatile memories as a critical phenomenon

    International Nuclear Information System (INIS)

    Bory, Benjamin F.; Meskers, Stefan C. J.; Rocha, Paulo R. F.; Gomes, Henrique L.; Leeuw, Dago M. de

    2015-01-01

    Diodes incorporating a bilayer of an organic semiconductor and a wide bandgap metal oxide can show unipolar, non-volatile memory behavior after electroforming. The prolonged bias voltage stress induces defects in the metal oxide with an areal density exceeding 10 17  m −2 . We explain the electrical bistability by the coexistence of two thermodynamically stable phases at the interface between an organic semiconductor and metal oxide. One phase contains mainly ionized defects and has a low work function, while the other phase has mainly neutral defects and a high work function. In the diodes, domains of the phase with a low work function constitute current filaments. The phase composition and critical temperature are derived from a 2D Ising model as a function of chemical potential. The model predicts filamentary conduction exhibiting a negative differential resistance and nonvolatile memory behavior. The model is expected to be generally applicable to any bilayer system that shows unipolar resistive switching

  8. Effect of tunneling layers on the performances of floating-gate based organic thin-film transistor nonvolatile memories

    International Nuclear Information System (INIS)

    Wang, Wei; Han, Jinhua; Ying, Jun; Xiang, Lanyi; Xie, Wenfa

    2014-01-01

    Two types of floating-gate based organic thin-film transistor nonvolatile memories (FG-OTFT-NVMs) were demonstrated, with poly(methyl methacrylate co glycidyl methacrylate) (P(MMA-GMA)) and tetratetracontane (TTC) as the tunneling layer, respectively. Their device performances were measured and compared. In the memory with a P(MMA-GMA) tunneling layer, typical unipolar hole transport was obtained with a relatively small mobility of 0.16 cm 2 /V s. The unidirectional shift of turn-on voltage (V on ) due to only holes trapped/detrapped in/from the floating gate resulted in a small memory window of 12.5 V at programming/erasing voltages (V P /V E ) of ±100 V and a nonzero reading voltage. Benefited from the well-ordered molecule orientation and the trap-free surface of TTC layer, a considerably high hole mobility of 1.7 cm 2 /V s and a visible feature of electrons accumulated in channel and trapped in floating-gate were achieved in the memory with a TTC tunneling layer. High hole mobility resulted in a high on current and a large memory on/off ratio of 600 at the V P /V E of ±100 V. Both holes and electrons were injected into floating-gate and overwritten each other, which resulted in a bidirectional V on shift. As a result, an enlarged memory window of 28.6 V at the V P /V E of ±100 V and a zero reading voltage were achieved. Based on our results, a strategy is proposed to optimize FG-OTFT-NVMs by choosing a right tunneling layer to improve the majority carrier mobility and realize ambipolar carriers injecting and trapping in the floating-gate.

  9. Effect of tunneling layers on the performances of floating-gate based organic thin-film transistor nonvolatile memories

    Science.gov (United States)

    Wang, Wei; Han, Jinhua; Ying, Jun; Xiang, Lanyi; Xie, Wenfa

    2014-09-01

    Two types of floating-gate based organic thin-film transistor nonvolatile memories (FG-OTFT-NVMs) were demonstrated, with poly(methyl methacrylate co glycidyl methacrylate) (P(MMA-GMA)) and tetratetracontane (TTC) as the tunneling layer, respectively. Their device performances were measured and compared. In the memory with a P(MMA-GMA) tunneling layer, typical unipolar hole transport was obtained with a relatively small mobility of 0.16 cm2/V s. The unidirectional shift of turn-on voltage (Von) due to only holes trapped/detrapped in/from the floating gate resulted in a small memory window of 12.5 V at programming/erasing voltages (VP/VE) of ±100 V and a nonzero reading voltage. Benefited from the well-ordered molecule orientation and the trap-free surface of TTC layer, a considerably high hole mobility of 1.7 cm2/V s and a visible feature of electrons accumulated in channel and trapped in floating-gate were achieved in the memory with a TTC tunneling layer. High hole mobility resulted in a high on current and a large memory on/off ratio of 600 at the VP/VE of ±100 V. Both holes and electrons were injected into floating-gate and overwritten each other, which resulted in a bidirectional Von shift. As a result, an enlarged memory window of 28.6 V at the VP/VE of ±100 V and a zero reading voltage were achieved. Based on our results, a strategy is proposed to optimize FG-OTFT-NVMs by choosing a right tunneling layer to improve the majority carrier mobility and realize ambipolar carriers injecting and trapping in the floating-gate.

  10. High-performance non-volatile organic ferroelectric memory on banknotes

    KAUST Repository

    Khan, Yasser; Bhansali, Unnat Sampatraj; Alshareef, Husam N.

    2012-01-01

    High-performance non-volatile polymer ferroelectric memory are fabricated on banknotes using poly(vinylidene fluoride trifluoroethylene). The devices show excellent performance with high remnant polarization, low operating voltages, low leakage

  11. A Retina-Like Dual Band Organic Photosensor Array for Filter-Free Near-Infrared-to-Memory Operations.

    Science.gov (United States)

    Wang, Hanlin; Liu, Hongtao; Zhao, Qiang; Ni, Zhenjie; Zou, Ye; Yang, Jie; Wang, Lifeng; Sun, Yanqiu; Guo, Yunlong; Hu, Wenping; Liu, Yunqi

    2017-08-01

    Human eyes use retina photoreceptor cells to absorb and distinguish photons from different wavelengths to construct an image. Mimicry of such a process and extension of its spectral response into the near-infrared (NIR) is indispensable for night surveillance, retinal prosthetics, and medical imaging applications. Currently, NIR organic photosensors demand optical filters to reduce visible interference, thus making filter-free and anti-visible NIR imaging a challenging task. To solve this limitation, a filter-free and conformal, retina-inspired NIR organic photosensor is presented. Featuring an integration of photosensing and floating-gate memory modules, the device possesses an acute color distinguishing capability. In general, the retina-like photosensor transduces NIR (850 nm) into nonvolatile memory and acts as a dynamic photoswitch under green light (550 nm). In doing this, a filter-free but color-distinguishing photosensor is demonstrated that selectively converts NIR optical signals into nonvolatile memory. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Effect of Ag nanoparticles on resistive switching of polyfluorene-based organic non-volatile memory devices

    International Nuclear Information System (INIS)

    Kim, Tae-Wook; Oh, Seung-Hwan; Choi, Hye-Jung; Wang, Gun-Uk; Kim, Dong-Yu; Hwang, Hyun-Sang; Lee, Tak-Hee

    2010-01-01

    The effects of Ag nanoparticles on the switching behavior of polyfluorene-based organic nonvolatile memory devices were investigated. Polyfluorene-derivatives (WPF-oxy-F) with and without Ag nanoparticles were synthesized, and the presence of Ag nanoparticles in Ag-WPF-oxy-F was identified by transmission electron microscopy and X-ray photoelectron spectroscopy analyses. The Ag-nanoparticles did not significantly affect the basic switching performances, such as the current-voltage characteristics, the distribution of on/off resistance, and the retention. The pulse switching time of Ag-WPF-oxy-F was faster than that of WPF-oxy-F. Ag-WPF-oxy-F memory devices showed an area dependence in the high resistance state, implying that formation of a Ag metallic channel for current conduction.

  13. Broadband infrared beam splitter for spaceborne interferometric infrared sounder.

    Science.gov (United States)

    Yu, Tianyan; Liu, Dingquan; Qin, Yang

    2014-10-01

    A broadband infrared beam splitter (BS) on ZnSe substrate used for the spaceborne interferometric infrared sounder (SIIRS) is studied in the spectral range of 4.44-15 μm. Both broadband antireflection coating and broadband beam-splitter coating in this BS are designed and tested. To optimize the optical properties and the stability of the BS, suitable infrared materials were selected, and improved deposition techniques were applied. The designed structures matched experimental data well, and the properties of the BS met the application specification of SIIRS.

  14. Incipient fault detection and power system protection for spaceborne systems

    Science.gov (United States)

    Russell, B. Don; Hackler, Irene M.

    1987-01-01

    A program was initiated to study the feasibility of using advanced terrestrial power system protection techniques for spacecraft power systems. It was designed to enhance and automate spacecraft power distribution systems in the areas of safety, reliability and maintenance. The proposed power management/distribution system is described as well as security assessment and control, incipient and low current fault detection, and the proposed spaceborne protection system. It is noted that the intelligent remote power controller permits the implementation of digital relaying algorithms with both adaptive and programmable characteristics.

  15. Inferential Costs of Trait Centrality in Impression Formation: Organization in Memory and Misremembering

    Directory of Open Access Journals (Sweden)

    Ludmila D. Nunes

    2017-08-01

    Full Text Available An extension of the DRM paradigm was used to study the impact of central traits (Asch, 1946 in impression formation. Traits corresponding to the four clusters of the implicit theory of personality—intellectual, positive and negative; and social, positive and negative (Rosenberg et al., 1968—were used to develop lists containing several traits of one cluster and one central trait prototypical of the opposite cluster. Participants engaging in impression formation relative to participants engaging in memorization not only produced higher levels of false memories corresponding to the same cluster of the list traits but, under response time pressure at retrieval, also produced more false memories of the cluster corresponding to the central trait. We argue that the importance of central traits stems from their ability to activate their corresponding semantic space within a specialized associative memory structure underlying the implicit theory of personality.

  16. Inferential Costs of Trait Centrality in Impression Formation: Organization in Memory and Misremembering

    Science.gov (United States)

    Nunes, Ludmila D.; Garcia-Marques, Leonel; Ferreira, Mário B.; Ramos, Tânia

    2017-01-01

    An extension of the DRM paradigm was used to study the impact of central traits (Asch, 1946) in impression formation. Traits corresponding to the four clusters of the implicit theory of personality—intellectual, positive and negative; and social, positive and negative (Rosenberg et al., 1968)—were used to develop lists containing several traits of one cluster and one central trait prototypical of the opposite cluster. Participants engaging in impression formation relative to participants engaging in memorization not only produced higher levels of false memories corresponding to the same cluster of the list traits but, under response time pressure at retrieval, also produced more false memories of the cluster corresponding to the central trait. We argue that the importance of central traits stems from their ability to activate their corresponding semantic space within a specialized associative memory structure underlying the implicit theory of personality. PMID:28878708

  17. Children's Representation and Imitation of Events: How Goal Organization Influences 3-Year-Old Children's Memory for Action Sequences.

    Science.gov (United States)

    Loucks, Jeff; Mutschler, Christina; Meltzoff, Andrew N

    2017-09-01

    Children's imitation of adults plays a prominent role in human cognitive development. However, few studies have investigated how children represent the complex structure of observed actions which underlies their imitation. We integrate theories of action segmentation, memory, and imitation to investigate whether children's event representation is organized according to veridical serial order or a higher level goal structure. Children were randomly assigned to learn novel event sequences either through interactive hands-on experience (Study 1) or via storybook (Study 2). Results demonstrate that children's representation of observed actions is organized according to higher level goals, even at the cost of representing the veridical temporal ordering of the sequence. We argue that prioritizing goal structure enhances event memory, and that this mental organization is a key mechanism of social-cognitive development in real-world, dynamic environments. It supports cultural learning and imitation in ecologically valid settings when social agents are multitasking and not demonstrating one isolated goal at a time. Copyright © 2016 Cognitive Science Society, Inc.

  18. Fattori di organizzazione del discorso nella memoria linguistica (Factors in Organizing Speech in Linguistic Memory)

    Science.gov (United States)

    Baroni, Maria Rosa; And Others

    1977-01-01

    An experiment was carried out to study the processes of linguistic memory. Subjects were asked to read aloud brief prose passages and repeat what they had read. The "deviations" from the original passages were analyzed to determine the time of the deviation, during decoding or recall. (Text is in Italian.) (CFM)

  19. High-performance non-volatile organic ferroelectric memory on banknotes

    KAUST Repository

    Khan, Yasser

    2012-03-21

    High-performance non-volatile polymer ferroelectric memory are fabricated on banknotes using poly(vinylidene fluoride trifluoroethylene). The devices show excellent performance with high remnant polarization, low operating voltages, low leakage, high mobility, and long retention times. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Verbal Memory Deficits in Relation to Organization Strategy in High- and Low-Functioning Autistic Children

    Science.gov (United States)

    Cheung, Mei-chun; Chan, Agnes S.; Sze, Sophia L.; Leung, Winnie W.; To, Cho Yee

    2010-01-01

    The present study examined the verbal memory profile and its relation to organizational strategies in high-functioning (Hi-AUT) and low-functioning (Lo-AUT) children with autism. Twenty-two Hi-AUT and 16 Lo-AUT, and 22 age-, gender- and handedness-matched normal children (NC) were required to remember a list of semantically related words for…

  1. High-performance non-volatile organic ferroelectric memory on banknotes.

    Science.gov (United States)

    Khan, M A; Bhansali, Unnat S; Alshareef, H N

    2012-04-24

    High-performance non-volatile polymer ferroelectric memory are fabricated on banknotes using poly(vinylidene fluoride trifluoroethylene). The devices show excellent performance with high remnant polarization, low operating voltages, low leakage, high mobility, and long retention times. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Self-Regulatory Private Speech Relates to Children's Recall and Organization of Autobiographical Memories

    Science.gov (United States)

    Al-Namlah, Abdulrahman S.; Meins, Elizabeth; Fernyhough, Charles

    2012-01-01

    We investigated relations between 4- and 7-year-olds' (N=58) autobiographical memory and their use of self-regulatory private speech in a non-mnemonic context (a cognitive planning task). Children's use of self-regulatory private speech during the planning task was associated with longer autobiographical narratives which included specific rather…

  3. Nonvolatile Memory Elements Based on the Intercalation of Organic Molecules Inside Carbon Nanotubes

    Science.gov (United States)

    Meunier, Vincent; Kalinin, Sergei V.; Sumpter, Bobby G.

    2007-02-01

    We propose a novel class of nonvolatile memory elements based on the modification of the transport properties of a conducting carbon nanotube by the presence of an encapsulated molecule. The guest molecule has two stable orientational positions relative to the nanotube that correspond to conducting and nonconducting states. The mechanism, governed by a local gating effect of the molecule on the electronic properties of the nanotube host, is studied using density functional theory. The mechanisms of reversible reading and writing of information are illustrated with a F4TCNQ molecule encapsulated inside a metallic carbon nanotube. Our results suggest that this new type of nonvolatile memory element is robust, fatigue-free, and can operate at room temperature.

  4. Low cost realization of space-borne synthectic aperture radar - MicroSAR

    Science.gov (United States)

    Carter, D.; Hall, C.

    Spaceborne Earth Observation data has been used for decades in the areas of meteorology and optical imaging. The systems and satellites have, in the main, been owned and operated by a few government institutions and agencies. More recently industrial organizations in North America have joined the list. Few of these, however, include Synthetic Aperture Radar (SAR)., although the additional utility in terms of all weather, 24 hour measurement capability over the Earth's surface is well recognized. Three major factors explain this:1) Relationships between the SAR measurements of radar backscatter and images to the specific information needs have not been seen as sufficiently well understood or robust2) Availability of suitable sources, at the relevant performance and data quality have been inadequate to provide service assurance that is necessary to sustain commercial businesses3) Costs associated with building, launching and operating spaceborne SAR have not been low enough as to achieve an acceptable return of investment. A significant amount of research and development has been undertaken throughout the World to establish reliable and robust algorithms for information extraction from SAR data. Much of this work has been carried out utilizing airborne systems over localized and carefully controlled regions. In addition, an increasing number of pilot services have been offered by geo-information providers. This has allowed customer confidence to grow. With the status of spaceborne SAR being effectively in the development phase, commercial funding has been scarce, and there has been need to rely on government and institutional budgets. Today the increasing maturity of the technology of SAR and its applications is beginning to attract the commercial sector. This is the funding necessary to realize sufficient assets to be able to provide a robust supply of SAR data to the geo-information providers and subsequently a reliable service to customers. Reducing the costs

  5. Integration of organic based Schottky junctions for crossbar non-volatile memory applications

    DEFF Research Database (Denmark)

    Katsia, E.; Tallarida, G.; Ferrari, S.

    2008-01-01

    Small size Schottky junctions using two different synthesized organic semiconductors (oligophenylene-vinylenes) were integrated by standard UV lithography into crossbar arrays. The proposed integration scheme can be applied to a wide class of organics without affecting material properties. Current...

  6. Novel Organic Phototransistor-Based Nonvolatile Memory Integrated with UV-Sensing/Green-Emissive Aggregation Enhanced Emission (AEE)-Active Aromatic Polyamide Electret Layer.

    Science.gov (United States)

    Cheng, Shun-Wen; Han, Ting; Huang, Teng-Yung; Chang Chien, Yu-Hsin; Liu, Cheng-Liang; Tang, Ben Zhong; Liou, Guey-Sheng

    2018-05-30

    A novel aggregation enhanced emission (AEE)-active polyamide TPA-CN-TPE with a high photoluminesence characteristic was successfully synthesized by the direct polymerization of 4-cyanotriphenyl diamine (TPA-CN) and tetraphenylethene (TPE)-containing dicarboxylic acid. The obtained luminescent polyamide plays a significant role as the polymer electret layer in organic field-effect transistors (OFETs)-type memory. The strong green emission of TPA-CN-TPE under ultraviolet (UV) irradiation can be directly absorbed by the pentacene channel, displaying a light-induced programming and voltage-driven erasing organic phototransistor-based nonvolatile memory. Memory window can be effectively manipulated between the programming and erasing states by applying UV light illumination and electrical field, respectively. The photoinduced memory behavior can be maintained for over 10 4 s between these two states with an on/off ratio of 10 4 , and the memory switching can be steadily operated for many cycles. With high photoresponsivity ( R) and photosensitivity ( S), this organic phototransistor integrated with AEE-active polyamide electret layer could serve as an excellent candidate for UV photodetectors in optical applications. For comparison, an AEE-inactive aromatic polyimide TPA-PIS electret with much weaker solid-state emission was also applied in the same OFETs device architecture, but this device did not show any UV-sensitive and UV-induced memory characteristics, which further confirmed the significance of the light-emitting capability of the electret layer.

  7. Spaceborne Radar for Mapping Forest and Land Use Changes

    DEFF Research Database (Denmark)

    Joshi, Neha Pankaj

    Degradation (REDD+). The implementation and effectiveness of such mechanisms relies partially on continuous observations of forests using satellite technology and partially on ground-based measurements of forest aboveground volume/biomass (AGV/AGB), carbon density and changes therein. Together, these means...... of forest monitoring enable the development of policies and measures to alter current trends in global forest and biodiversity loss. This thesis investigates the use of long wavelength (~23 cm, L-band) spaceborne radar, which has all-weather and canopy-penetration capabilities, acquired by the Advanced Land...... Observing Satellite (ALOS) for forest monitoring. Using a combination of local expert knowledge, plot inventories, and data from lidar and optical sensors, it aims to understand (1) whether forest disturbance dynamics may be detected with radar, and (2) what physical and macroecological properties influence...

  8. Spaceborne Lidar in the Study of Marine Systems.

    Science.gov (United States)

    Hostetler, Chris A; Behrenfeld, Michael J; Hu, Yongxiang; Hair, Johnathan W; Schulien, Jennifer A

    2018-01-03

    Satellite passive ocean color instruments have provided an unbroken ∼20-year record of global ocean plankton properties, but this measurement approach has inherent limitations in terms of spatial-temporal sampling and ability to resolve vertical structure within the water column. These limitations can be addressed by coupling ocean color data with measurements from a spaceborne lidar. Airborne lidars have been used for decades to study ocean subsurface properties, but recent breakthroughs have now demonstrated that plankton properties can be measured with a satellite lidar. The satellite lidar era in oceanography has arrived. Here, we present a review of the lidar technique, its applications in marine systems, a perspective on what can be accomplished in the near future with an ocean- and atmosphere-optimized satellite lidar, and a vision for a multiplatform virtual constellation of observational assets that would enable a three-dimensional reconstruction of global ocean ecosystems.

  9. Ocean subsurface particulate backscatter estimation from CALIPSO spaceborne lidar measurements

    Science.gov (United States)

    Chen, Peng; Pan, Delu; Wang, Tianyu; Mao, Zhihua

    2017-10-01

    A method for ocean subsurface particulate backscatter estimation from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite was demonstrated. The effects of the CALIOP receiver's transient response on the attenuated backscatter profile were first removed. The two-way transmittance of the overlying atmosphere was then estimated as the ratio of the measured ocean surface attenuated backscatter to the theoretical value computed from wind driven wave slope variance. Finally, particulate backscatter was estimated from the depolarization ratio as the ratio of the column-integrated cross-polarized and co-polarized channels. Statistical results show that the derived particulate backscatter by the method based on CALIOP data agree reasonably well with chlorophyll-a concentration using MODIS data. It indicates a potential use of space-borne lidar to estimate global primary productivity and particulate carbon stock.

  10. Spaceborne Lidar in the Study of Marine Systems

    Science.gov (United States)

    Hostetler, Chris A.; Behrenfeld, Michael J.; Hu, Yongxiang; Hair, Johnathan W.; Schulien, Jennifer A.

    2018-01-01

    Satellite passive ocean color instruments have provided an unbroken ˜20-year record of global ocean plankton properties, but this measurement approach has inherent limitations in terms of spatial-temporal sampling and ability to resolve vertical structure within the water column. These limitations can be addressed by coupling ocean color data with measurements from a spaceborne lidar. Airborne lidars have been used for decades to study ocean subsurface properties, but recent breakthroughs have now demonstrated that plankton properties can be measured with a satellite lidar. The satellite lidar era in oceanography has arrived. Here, we present a review of the lidar technique, its applications in marine systems, a perspective on what can be accomplished in the near future with an ocean- and atmosphere-optimized satellite lidar, and a vision for a multiplatform virtual constellation of observational assets that would enable a three-dimensional reconstruction of global ocean ecosystems.

  11. Efficient and compact hyperspectral imager for space-borne applications

    Science.gov (United States)

    Pisani, Marco; Zucco, Massimo

    2017-11-01

    In the last decades Hyperspectral Imager (HI) have become irreplaceable space-borne instruments for an increasing number of applications. A number of HIs are now operative onboard (e.g. CHRIS on PROBA), others are going to be launched (e.g. PRISMA, EnMAP, HyspIRI), many others are at the breadboard level. The researchers goal is to realize HI with high spatial and spectral resolution, having low weight and contained dimensions. The most common HI technique is based on the use of a dispersive mean (a grating or a prism) or on the use of band pass filters (tunable or linear variable). These approaches have the advantages of allowing compact devices. Another approach is based on the use of interferometer based spectrometers (Michelson or Sagnac type). The advantage of the latter is a very high efficiency in light collection because of the well-known Felgett and Jaquinot principles.

  12. Improved spatial mapping of rainfall events with spaceborne SAR imagery

    Science.gov (United States)

    Ulaby, F. T.; Brisco, B.; Dobson, C.

    1983-01-01

    The Seasat satellite acquired the first spaceborne synthetic-aperture radar (SAR) images of the earth's surface, in 1978, at a frequency of 1.275 GHz (L-band) in a like-polarization mode at incidence angles of 23 + or - 3 deg. Although this may not be the optimum system configuration for radar remote sensing of soil moisture, interpretation of two Seasat images of Iowa demonstrates the sensitivity of microwave backscatter to soil moisture content. In both scenes, increased image brightness, which represents more radar backscatter, can be related to previous rainfall activity in the two areas. Comparison of these images with ground-based rainfall observations illustrates the increased spatial coverage of the rainfall event that can be obtained from the satellite SAR data. These data can then be color-enhanced by a digital computer to produce aesthetically pleasing output products for the user community.

  13. Highly-reliable laser diodes and modules for spaceborne applications

    Science.gov (United States)

    Deichsel, E.

    2017-11-01

    Laser applications become more and more interesting in contemporary missions such as earth observations or optical communication in space. One of these applications is light detection and ranging (LIDAR), which comprises huge scientific potential in future missions. The Nd:YAG solid-state laser of such a LIDAR system is optically pumped using 808nm emitting pump sources based on semiconductor laser-diodes in quasi-continuous wave (qcw) operation. Therefore reliable and efficient laser diodes with increased output powers are an important requirement for a spaceborne LIDAR-system. In the past, many tests were performed regarding the performance and life-time of such laser-diodes. There were also studies for spaceborne applications, but a test with long operation times at high powers and statistical relevance is pending. Other applications, such as science packages (e.g. Raman-spectroscopy) on planetary rovers require also reliable high-power light sources. Typically fiber-coupled laser diode modules are used for such applications. Besides high reliability and life-time, designs compatible to the harsh environmental conditions must be taken in account. Mechanical loads, such as shock or strong vibration are expected due to take-off or landing procedures. Many temperature cycles with high change rates and differences must be taken in account due to sun-shadow effects in planetary orbits. Cosmic radiation has strong impact on optical components and must also be taken in account. Last, a hermetic sealing must be considered, since vacuum can have disadvantageous effects on optoelectronics components.

  14. Visuospatial working memory in children with autism: the effect of a semantic global organization.

    Science.gov (United States)

    Mammarella, Irene C; Giofrè, David; Caviola, Sara; Cornoldi, Cesare; Hamilton, Colin

    2014-06-01

    It has been reported that individuals with Autism Spectrum Disorders (ASD) perceive visual scenes as a sparse set of details rather than as a congruent and meaningful unit, failing in the extraction of the global configuration of the scene. In the present study, children with ASD were compared with typically developing (TD) children, in a visuospatial working memory task, the Visual Patterns Test (VPT). The VPT array was manipulated to vary the semantic affordance of the pattern, high semantic (global) vs. low semantic; temporal parameters were also manipulated within the change detection protocol. Overall, there was no main effect associated with Group, however there was a significant effect associated with Semantics, which was further qualified by an interaction between the Group and Semantic factors; there was only a significant effect of semantics in the TD group. The findings are discussed in light of the weak central coherence theory where the ASD group are unable to make use of long term memory semantics in order to construct global representations of the array. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Organizing distributed knowledge for collaborative action: Structure, functioning, and emergence of organizational transactive memory systems

    NARCIS (Netherlands)

    Schakel, J.K.

    2013-01-01

    In the domain of safety and security specialized organizations often have to collaborate on an occasional basis with other organizations to head challenges that none of the partners can head (as easily) on its own. Such collaborations are temporal and often virtual in nature. One emerging

  16. Genetic correlations between brain volumes and the WAIS-III dimensions of verbal comprehension, working memory, perceptual organization, and processing speed

    DEFF Research Database (Denmark)

    Posthuma, Daniëlle; Baare, Wim F.C.; Hulshoff Pol, Hilleke E.

    2003-01-01

    We recently showed that the correlation of gray and white matter volume with full scale IQ and the Working Memory dimension are completely mediated by common genetic factors (Posthuma et al., 2002). Here we examine whether the other WAIS III dimensions (Verbal Comprehension, Perceptual Organization...... to Working Memory capacity (r = 0.27). This phenotypic correlation is completely due to a common underlying genetic factor. Processing Speed was genetically related to white matter volume (r(g) = 0.39). Perceptual Organization was both genetically (r(g) = 0.39) and environmentally (r(e) = -0.71) related...

  17. Organic nonvolatile resistive memory devices based on thermally deposited Au nanoparticle

    Science.gov (United States)

    Jin, Zhiwen; Liu, Guo; Wang, Jizheng

    2013-05-01

    Uniform Au nanoparticles (NPs) are formed by thermally depositing nominal 2-nm thick Au film on a 10-nm thick polyimide film formed on a Al electrode, and then covered by a thin polymer semiconductor film, which acts as an energy barrier for electrons to be injected from the other Al electrode (on top of polymer film) into the Au NPs, which are energetically electron traps in such a resistive random access memory (RRAM) device. The Au NPs based RRAM device exhibits estimated retention time of 104 s, cycle times of more than 100, and ON-OFF ratio of 102 to 103. The carrier transport properties are also analyzed by fitting the measured I-V curves with several conduction models.

  18. Direct probing of electron and hole trapping into nano-floating-gate in organic field-effect transistor nonvolatile memories

    Energy Technology Data Exchange (ETDEWEB)

    Cui, Ze-Qun; Wang, Shun; Chen, Jian-Mei; Gao, Xu; Dong, Bin, E-mail: wangsd@suda.edu.cn, E-mail: chilf@suda.edu.cn, E-mail: bdong@suda.edu.cn; Chi, Li-Feng, E-mail: wangsd@suda.edu.cn, E-mail: chilf@suda.edu.cn, E-mail: bdong@suda.edu.cn; Wang, Sui-Dong, E-mail: wangsd@suda.edu.cn, E-mail: chilf@suda.edu.cn, E-mail: bdong@suda.edu.cn [Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu 215123 (China)

    2015-03-23

    Electron and hole trapping into the nano-floating-gate of a pentacene-based organic field-effect transistor nonvolatile memory is directly probed by Kelvin probe force microscopy. The probing is straightforward and non-destructive. The measured surface potential change can quantitatively profile the charge trapping, and the surface characterization results are in good accord with the corresponding device behavior. Both electrons and holes can be trapped into the nano-floating-gate, with a preference of electron trapping than hole trapping. The trapped charge quantity has an approximately linear relation with the programming/erasing gate bias, indicating that the charge trapping in the device is a field-controlled process.

  19. Direct probing of electron and hole trapping into nano-floating-gate in organic field-effect transistor nonvolatile memories

    International Nuclear Information System (INIS)

    Cui, Ze-Qun; Wang, Shun; Chen, Jian-Mei; Gao, Xu; Dong, Bin; Chi, Li-Feng; Wang, Sui-Dong

    2015-01-01

    Electron and hole trapping into the nano-floating-gate of a pentacene-based organic field-effect transistor nonvolatile memory is directly probed by Kelvin probe force microscopy. The probing is straightforward and non-destructive. The measured surface potential change can quantitatively profile the charge trapping, and the surface characterization results are in good accord with the corresponding device behavior. Both electrons and holes can be trapped into the nano-floating-gate, with a preference of electron trapping than hole trapping. The trapped charge quantity has an approximately linear relation with the programming/erasing gate bias, indicating that the charge trapping in the device is a field-controlled process

  20. A Comparison between Local and Global Spaceborne Chlorophyll Indices in the St. Lawrence Estuary

    Directory of Open Access Journals (Sweden)

    Martin A. Montes-Hugo

    2012-11-01

    Full Text Available Spaceborne chlorophyll indices based on red fluorescence (wavelength = 680 nm and water leaving radiance (Lw in the visible spectrum (i.e., 400–700 nm were evaluated in the St Lawrence Estuary (SLE during September of 2011. Relationships between chlorophyll concentration (chl and fluorescence were constructed based on fluorescence line height (FLH measurements derived from a compact laser-based spectrofluorometer developed by ENEA (CASPER and using spectral bands corresponding to the satellite sensor MERIS (MEdium Resolution Imaging Spectrometer. Chlorophyll concentration as estimated from CASPER (chlCASPER was relatively high NE of the MTZ (upper Estuary, and nearby areas influenced by fronts or freshwater plumes derived from secondary rivers (lower estuary. These findings agree with historical shipboard measurements. In general, global chl products calculated from Lw had large biases (up to 27-fold overestimation and 50-fold underestimation with respect to chlCASPER values. This was attributed to the smaller interference of detritus (mineral + organic non-living particulates and chromophoric dissolved organic matter on chlCASPER estimates. We encourage the use of spectrofluorometry for developing and validating remote sensing models of chl in SLE waters and other coastal environments characterized by relatively low to moderate (<10 g·m−3 concentrations of detritus.

  1. Feasibility Study on Passive-radar Detection of Space Targets Using Spaceborne Illuminators of Opportunity

    Directory of Open Access Journals (Sweden)

    Jiang Tie-zhen

    2015-01-01

    Full Text Available Space target surveillance generally uses active radars. To take full advantage of passive radars, the idea of using spaceborne illuminators of opportunity for space target detection is presented in this paper. Analysis of the detectable time and direct wave suppression shows that passive radar using spaceborne illuminators of opportunity can effectively detect a Low-Earth-Orbit (LEO target. Meanwhile, Ku and L band bi-static radar cross section of passive radars that use spaceborne illuminators of opportunity are presented by simulation, providing the basis of choosing space target forward scatter. Finally the key parameters, mainly system gain, accumulation time and radiation source selection are studied. Results show that system size using satellite TV signals as illuminators of opportunity is relatively small. These encouraging results should stimulate the development of passive radar detection of space targets using spaceborne illuminators of opportunity.

  2. Neurophysiology of spectrotemporal cue organization of spoken language in auditory memory.

    Science.gov (United States)

    Moberly, Aaron C; Bhat, Jyoti; Welling, D Bradley; Shahin, Antoine J

    2014-03-01

    Listeners assign different weights to spectral dynamics, such as formant rise time (FRT), and temporal dynamics, such as amplitude rise time (ART), during phonetic judgments. We examined the neurophysiological basis of FRT and ART weighting in the /ba/-/wa/ contrast. Electroencephalography was recorded for thirteen adult English speakers during a mismatch negativity (MMN) design using synthetic stimuli: a /ba/ with /ba/-like FRT and ART; a /wa/ with /wa/-like FRT and ART; and a /ba/(wa) with /ba/-like FRT and /wa/-like ART. We hypothesized that because of stronger reliance on FRT, subjects would encode a stronger memory trace and exhibit larger MMN during the FRT than the ART contrast. Results supported this hypothesis. The effect was most robust in the later portion of MMN. Findings suggest that MMN is generated by multiple sources, differentially reflecting acoustic change detection (earlier MMN, bottom-up process) and perceptual weighting of ART and FRT (later MMN, top-down process). Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Simulating return signals of a spaceborne high-spectral resolution lidar channel at 532 nm

    Science.gov (United States)

    Xiao, Yu; Binglong, Chen; Min, Min; Xingying, Zhang; Lilin, Yao; Yiming, Zhao; Lidong, Wang; Fu, Wang; Xiaobo, Deng

    2018-06-01

    High spectral resolution lidar (HSRL) system employs a narrow spectral filter to separate the particulate (cloud/aerosol) and molecular scattering components in lidar return signals, which improves the quality of the retrieved cloud/aerosol optical properties. To better develop a future spaceborne HSRL system, a novel simulation technique was developed to simulate spaceborne HSRL return signals at 532 nm using the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) cloud/aerosol extinction coefficients product and numerical weather prediction data. For validating simulated data, a mathematical particulate extinction coefficient retrieval method for spaceborne HSRL return signals is described here. We compare particulate extinction coefficient profiles from the CALIPSO operational product with simulated spaceborne HSRL data. Further uncertainty analysis shows that relative uncertainties are acceptable for retrieving the optical properties of cloud and aerosol. The final results demonstrate that they agree well with each other. It indicates that the return signals of the spaceborne HSRL molecular channel at 532 nm will be suitable for developing operational algorithms supporting a future spaceborne HSRL system.

  4. Genetic correlations between brain volumes and the WAIS-III dimensions of verbal comprehension, working memory, perceptual organization, and processing speed

    NARCIS (Netherlands)

    Posthuma, D.; Baare, W.F.C.; Hulshoff Pol, H.E.; Kahn, R.S.; Boomsma, D.I.; de Geus, E.J.C.

    2003-01-01

    We recently showed that the correlation of gray and white matter volume with full scale IQ and the Working Memory dimension are completely mediated by common genetic factors (Posthuma et al., 2002). Here we examine whether the other WAIS III dimensions (Verbal Comprehension, Perceptual Organization,

  5. Uncertainty Assessment of Space-Borne Passive Soil Moisture Retrievals

    Science.gov (United States)

    Quets, Jan; De Lannoy, Gabrielle; Reichle, Rolf; Cosh, Michael; van der Schalie, Robin; Wigneron, Jean-Pierre

    2017-01-01

    The uncertainty associated with passive soil moisture retrieval is hard to quantify, and known to be underlain by various, diverse, and complex causes. Factors affecting space-borne retrieved soil moisture estimation include: (i) the optimization or inversion method applied to the radiative transfer model (RTM), such as e.g. the Single Channel Algorithm (SCA), or the Land Parameter Retrieval Model (LPRM), (ii) the selection of the observed brightness temperatures (Tbs), e.g. polarization and incidence angle, (iii) the definition of the cost function and the impact of prior information in it, and (iv) the RTM parameterization (e.g. parameterizations officially used by the SMOS L2 and SMAP L2 retrieval products, ECMWF-based SMOS assimilation product, SMAP L4 assimilation product, and perturbations from those configurations). This study aims at disentangling the relative importance of the above-mentioned sources of uncertainty, by carrying out soil moisture retrieval experiments, using SMOS Tb observations in different settings, of which some are mentioned above. The ensemble uncertainties are evaluated at 11 reference CalVal sites, over a time period of more than 5 years. These experimental retrievals were inter-compared, and further confronted with in situ soil moisture measurements and operational SMOS L2 retrievals, using commonly used skill metrics to quantify the temporal uncertainty in the retrievals.

  6. Spaceborne Differential SAR Interferometry: Data Analysis Tools for Deformation Measurement

    Directory of Open Access Journals (Sweden)

    Michele Crosetto

    2011-02-01

    Full Text Available This paper is focused on spaceborne Differential Interferometric SAR (DInSAR for land deformation measurement and monitoring. In the last two decades several DInSAR data analysis procedures have been proposed. The objective of this paper is to describe the DInSAR data processing and analysis tools developed at the Institute of Geomatics in almost ten years of research activities. Four main DInSAR analysis procedures are described, which range from the standard DInSAR analysis based on a single interferogram to more advanced Persistent Scatterer Interferometry (PSI approaches. These different procedures guarantee a sufficient flexibility in DInSAR data processing. In order to provide a technical insight into these analysis procedures, a whole section discusses their main data processing and analysis steps, especially those needed in PSI analyses. A specific section is devoted to the core of our PSI analysis tools: the so-called 2+1D phase unwrapping procedure, which couples a 2D phase unwrapping, performed interferogram-wise, with a kind of 1D phase unwrapping along time, performed pixel-wise. In the last part of the paper, some examples of DInSAR results are discussed, which were derived by standard DInSAR or PSI analyses. Most of these results were derived from X-band SAR data coming from the TerraSAR-X and CosmoSkyMed sensors.

  7. W-band spaceborne radar observations of atmospheric river events

    Science.gov (United States)

    Matrosov, S. Y.

    2010-12-01

    While the main objective of the world first W-band radar aboard the CloudSat satellite is to provide vertically resolved information on clouds, it proved to be a valuable tool for observing precipitation. The CloudSat radar is generally able to resolve precipitating cloud systems in their vertical entirety. Although measurements from the liquid hydrometer layer containing rainfall are strongly attenuated, special retrieval approaches can be used to estimate rainfall parameters. These approaches are based on vertical gradients of observed radar reflectivity factor rather than on absolute estimates of reflectivity. Concurrent independent estimations of ice cloud parameters in the same vertical column allow characterization of precipitating systems and provide information on coupling between clouds and rainfall they produce. The potential of CloudSat for observations atmospheric river events affecting the West Coast of North America is evaluated. It is shown that spaceborne radar measurements can provide high resolution information on the height of the freezing level thus separating areas of rainfall and snowfall. CloudSat precipitation rate estimates complement information from the surface-based radars. Observations of atmospheric rivers at different locations above the ocean and during landfall help to understand evolutions of atmospheric rivers and their structures.

  8. MIDAS: Lessons learned from the first spaceborne atomic force microscope

    Science.gov (United States)

    Bentley, Mark Stephen; Arends, Herman; Butler, Bart; Gavira, Jose; Jeszenszky, Harald; Mannel, Thurid; Romstedt, Jens; Schmied, Roland; Torkar, Klaus

    2016-08-01

    The Micro-Imaging Dust Analysis System (MIDAS) atomic force microscope (AFM) onboard the Rosetta orbiter was the first such instrument launched into space in 2004. Designed only a few years after the technique was invented, MIDAS is currently orbiting comet 67P Churyumov-Gerasimenko and producing the highest resolution 3D images of cometary dust ever made in situ. After more than a year of continuous operation much experience has been gained with this novel instrument. Coupled with operations of the Flight Spare and advances in terrestrial AFM a set of "lessons learned" has been produced, cumulating in recommendations for future spaceborne atomic force microscopes. The majority of the design could be reused as-is, or with incremental upgrades to include more modern components (e.g. the processor). Key additional recommendations are to incorporate an optical microscope to aid the search for particles and image registration, to include a variety of cantilevers (with different spring constants) and a variety of tip geometries.

  9. Spaceborne Polarimetric SAR Interferometry: Performance Analysis and Mission Concepts

    Directory of Open Access Journals (Sweden)

    Shane R. Cloude

    2005-12-01

    Full Text Available We investigate multichannel imaging radar systems employing coherent combinations of polarimetry and interferometry (Pol-InSAR. Such systems are well suited for the extraction of bio- and geophysical parameters by evaluating the combined scattering from surfaces and volumes. This combination leads to several important differences between the design of Pol-InSAR sensors and conventional single polarisation SAR interferometers. We first highlight these differences and then investigate the Pol-InSAR performance of two proposed spaceborne SAR systems (ALOS/PalSAR and TerraSAR-L operating in repeat-pass mode. For this, we introduce the novel concept of a phase tube which enables (1 a quantitative assessment of the Pol-InSAR performance, (2 a comparison between different sensor configurations, and (3 an optimization of the instrument settings for different Pol-InSAR applications. The phase tube may hence serve as an interface between system engineers and application-oriented scientists. The performance analysis reveals major limitations for even moderate levels of temporal decorrelation. Such deteriorations may be avoided in single-pass sensor configurations and we demonstrate the potential benefits from the use of future bi- and multistatic SAR interferometers.

  10. Photoresponse and photo-induced memory effect in the organic field-effect transistor based on AlOX nanoparticles at the interface of semiconductor/dielectric

    Science.gov (United States)

    Cheng, Yunfei; Wang, Wu

    2017-10-01

    In this work, the photoresponse and photo-induced memory effect were demonstrated in an organic field-effect transistor (OFET) with semiconductor pentacene and SiO2 as the active and gate dielectric layers, respectively. By inserting AlOX nanoparticles (NPs) at the interface of pentacene/SiO2, obvious enhancing photoresponse was obtained in the OFET with the maximum responsivity and photosensitivity of about 15 A/W and 100, respectively. Moreover, the stable photoinduced memory effect was achieved in the OFET, attributing to the photogenerated electrons captured by the interface traps of the AlOX NPs/SiO2.

  11. Performance Simulations for a Spaceborne Methane Lidar Mission

    Science.gov (United States)

    Kiemle, C.; Kawa, Stephan Randolph; Quatrevalet, Mathieu; Browell, Edward V.

    2014-01-01

    Future spaceborne lidar measurements of key anthropogenic greenhouse gases are expected to close current observational gaps particularly over remote, polar, and aerosol-contaminated regions, where actual in situ and passive remote sensing observation techniques have difficulties. For methane, a "Methane Remote Lidar Mission" was proposed by Deutsches Zentrum fuer Luft- und Raumfahrt and Centre National d'Etudes Spatiales in the frame of a German-French climate monitoring initiative. Simulations assess the performance of this mission with the help of Moderate Resolution Imaging Spectroradiometer and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations of the earth's surface albedo and atmospheric optical depth. These are key environmental parameters for integrated path differential absorption lidar which uses the surface backscatter to measure the total atmospheric methane column. Results showthat a lidar with an average optical power of 0.45W at 1.6 µm wavelength and a telescope diameter of 0.55 m, installed on a low Earth orbit platform(506 km), will measure methane columns at precisions of 1.2%, 1.7%, and 2.1% over land, water, and snow or ice surfaces, respectively, for monthly aggregated measurement samples within areas of 50 × 50 km2. Globally, the mean precision for the simulated year 2007 is 1.6%, with a standard deviation of 0.7%. At high latitudes, a lower reflectance due to snow and ice is compensated by denser measurements, owing to the orbital pattern. Over key methane source regions such as densely populated areas, boreal and tropical wetlands, or permafrost, our simulations show that the measurement precision will be between 1 and 2%.

  12. Four Decades of Space-Borne Radio Sounding

    Science.gov (United States)

    Benson, Robert F.

    2010-01-01

    A review is given of the 38 rocket, satellite, and planetary payloads dedicated to ionospheric/magnetospheric radio sounding since 1961. Between 1961 and 1995, eleven sounding-rocket payloads from four countries evolved from proof-of-concept flights to sophisticated instruments. Some involved dual payloads, with the sounder transmitter on one and the sounder receiver on the other. The rocket sounders addressed specific space-plasma-wave questions, and provided improved measurements of ionospheric electron-density (N(sub e)) field-aligned irregularities (FAI). Four countries launched 12 ionospheric topside-sounder satellites between 1962 and 1994, and an ionospheric sounder was placed on the Mir Space Station in 1998. Eleven magnetospheric radio sounders, most of the relaxation type, were launched from 1977 to 2000. The relaxation sounders used low-power transmitters, designed to stimulate plasma resonances for accurate local Ne determinations. The latest magnetospheric sounder designed for remote sensing incorporated long antennas and digital signal processing techniques to overcome the challenges posed by low Ne values and large propagation distances. Three radio sounders from three countries were included on payloads to extraterrestrial destinations from 1990 to 2003. The scientific accomplishments of space-borne radio sounders included (1) a wealth of global N(sub e) information on the topside ionosphere and magnetosphere, based on vertical and magnetic-field-aligned N(sub e) profiles; (2) accurate in-situ N(sub e) values, even under low-density conditions; and (3) fundamental advances in our understanding of the excitation and propagation of plasma waves, which have even led to the prediction of a new plasma-wave mode.

  13. Molecular control of memory in nematode Caenorhabditis elegans

    OpenAIRE

    Ye, Hua-Yue; Ye, Bo-Ping; Wang, Da-Yong

    2008-01-01

    Model invertebrate organism Caenorhabditis elegans has become an ideal model to unravel the complex processes of memory. C. elegans has three simple forms of memory: memory for thermosensation, memory for chemosensation, and memory for mechanosensation. In the form of memory for mechanosensation, short-term memory, intermediate-term memory, and long-term memory have been extensively studied. The short-term memory and intermediate-term memory may occur in the presynaptic sensory neurons, where...

  14. What Makes Grassroots Conservation Organizations Resilient? An Empirical Analysis of Diversity, Organizational Memory, and the Number of Leaders

    Science.gov (United States)

    Baral, Nabin

    2013-03-01

    Conservation Area Management Committees (CAMCs)—the functional decision-making units consisting entirely of local villagers—are grassroots organizations legally established to manage the Annapurna Conservation Area (ACA) in Nepal. These committees suffered due to the decade-long Maoist insurgency, but they survived. The paper attempts to test what factors contributed to their resiliency. For this, I surveyed 30 CAMCs during the summer of 2007 and conducted semi-structured interviews of 190 executive members of the CAMCs and 13 park officials who closely monitor the CAMCs. Regression results showed that the number of leaders ( b = 0.44, t = 2.38, P = .027) was the most critical variable for building the resilience of CAMCs to the Maoist insurgency, i.e., retaining the same function, structure, and identity of the committees. As there were no reported conflicts among leaders and they were involved in negotiations and devising contingency plans, CAMCs actually benefited from having more leaders. Of the three diversity indices, the quadratic terms of age diversity ( b = -5.42, t = 1.95, P = .064) and ethnic diversity ( b = -4.05, t = 1.78, P = .075) had a negative impact on the CAMCs' resilience. Skill diversity and organizational memory had no significant influence on the CAMCs' resilience ( t .10). These results have important implications for building resilience in community-based conservation.

  15. Direct visualization of polarization reversal of organic ferroelectric memory transistor by using charge modulated reflectance imaging

    Science.gov (United States)

    Otsuka, Takako; Taguchi, Dai; Manaka, Takaaki; Iwamoto, Mitsumasa

    2017-11-01

    By using the charge modulated reflectance (CMR) imaging technique, charge distribution in the pentacene organic field-effect transistor (OFET) with a ferroelectric gate insulator [P(VDF-TrFE)] was investigated in terms of polarization reversal of the P(VDF-TrFE) layer. We studied the polarization reversal process and the carrier spreading process in the OFET channel. The I-V measurement showed a hysteresis behavior caused by the spontaneous polarization of P(VDF-TrFE), but the hysteresis I-V curve changes depending on the applied drain bias, possibly due to the gradual shift of the polarization reversal position in the OFET channel. CMR imaging visualized the gradual shift of the polarization reversal position and showed that the electrostatic field formed by the polarization of P(VDF-TrFE) contributes to hole and electron injection into the pentacene layer and the carrier distribution is significantly dependent on the direction of the polarization. The polarization reversal position in the channel region is governed by the electrostatic potential, and it happens where the potential reaches the coercive voltage of P(VDF-TrFE). The transmission line model developed on the basis of the Maxwell-Wagner effect element analysis well accounts for this polarization reversal process in the OFET channel.

  16. The influence of learning methods on collaboration: prior repeated retrieval enhances retrieval organization, abolishes collaborative inhibition, and promotes post-collaborative memory.

    Science.gov (United States)

    Congleton, Adam R; Rajaram, Suparna

    2011-11-01

    Research on collaborative memory has unveiled the counterintuitive yet robust phenomenon that collaboration impairs group recall. A candidate explanation for this collaborative inhibition effect is the disruption of people's idiosyncratic retrieval strategies during collaboration, and it is hypothesized that employing methods that improve one's organization protects against retrieval disruption. Here it is investigated how one's learning method during the study phase--defined as either repeatedly studying or repeatedly retrieving information--influences retrieval organization and what effects this has on collaborative recall and post-collaborative individual recall. Results show that repeated retrieval consistently eliminated collaborative inhibition. This enabled participants to gain the most from re-exposure to materials recalled by their partners that they themselves did not recall and led to improvements in their individual memory following collaboration. This repeated retrieval advantage stemmed from the preferential manner in which this learning method strengthened retrieval organization. Findings are also discussed that reveal a relationship between retrieval organization and the interaction observed between learning method and short versus long delay seen in the testing effect literature. Finally, results show that the elusive benefits of cross-cuing during collaboration may be best detected with a longer study-test delay. Together, these findings illuminate when and how collaboration can enhance memory.

  17. Memory T Cell Migration

    OpenAIRE

    Qianqian eZhang; Qianqian eZhang; Fadi G. Lakkis

    2015-01-01

    Immunological memory is a key feature of adaptive immunity. It provides the organism with long-lived and robust protection against infection. In organ transplantation, memory T cells pose a significant threat by causing allograft rejection that is generally resistant to immunosuppressive therapy. Therefore, a more thorough understanding of memory T cell biology is needed to improve the survival of transplanted organs without compromising the host’s ability to fight infections. This review...

  18. Role of serial order in the impact of talker variability on short-term memory: testing a perceptual organization-based account.

    Science.gov (United States)

    Hughes, Robert W; Marsh, John E; Jones, Dylan M

    2011-11-01

    In two experiments, we examined the impact of the degree of match between sequential auditory perceptual organization processes and the demands of a short-term memory task (memory for order vs. item information). When a spoken sequence of digits was presented so as to promote its perceptual partitioning into two distinct streams by conveying it in alternating female (F) and male (M) voices (FMFMFMFM)--thereby disturbing the perception of true temporal order--recall of item order was greatly impaired (as compared to recall of item identity). Moreover, an order error type consistent with the formation of voice-based streams was committed more quickly in the alternating-voice condition (Exp. 1). In contrast, when the perceptual organization of the sequence mapped well onto an optimal two-group serial rehearsal strategy--by presenting the two voices in discrete clusters (FFFFMMMM)--order, but not item, recall was enhanced (Exp. 2). The results are consistent with the view that the degree of compatibility between perceptual and deliberate sequencing processes is a key determinant of serial short-term memory performance. Alternative accounts of talker variability effects in short-term memory, based on the concept of a dedicated phonological short-term store and a capacity-limited focus of attention, are also reviewed.

  19. Organic Ferroelectric-Based 1T1T Random Access Memory Cell Employing a Common Dielectric Layer Overcoming the Half-Selection Problem.

    Science.gov (United States)

    Zhao, Qiang; Wang, Hanlin; Ni, Zhenjie; Liu, Jie; Zhen, Yonggang; Zhang, Xiaotao; Jiang, Lang; Li, Rongjin; Dong, Huanli; Hu, Wenping

    2017-09-01

    Organic electronics based on poly(vinylidenefluoride/trifluoroethylene) (P(VDF-TrFE)) dielectric is facing great challenges in flexible circuits. As one indispensable part of integrated circuits, there is an urgent demand for low-cost and easy-fabrication nonvolatile memory devices. A breakthrough is made on a novel ferroelectric random access memory cell (1T1T FeRAM cell) consisting of one selection transistor and one ferroelectric memory transistor in order to overcome the half-selection problem. Unlike complicated manufacturing using multiple dielectrics, this system simplifies 1T1T FeRAM cell fabrication using one common dielectric. To achieve this goal, a strategy for semiconductor/insulator (S/I) interface modulation is put forward and applied to nonhysteretic selection transistors with high performances for driving or addressing purposes. As a result, high hole mobility of 3.81 cm 2 V -1 s -1 (average) for 2,6-diphenylanthracene (DPA) and electron mobility of 0.124 cm 2 V -1 s -1 (average) for N,N'-1H,1H-perfluorobutyl dicyanoperylenecarboxydiimide (PDI-FCN 2 ) are obtained in selection transistors. In this work, we demonstrate this technology's potential for organic ferroelectric-based pixelated memory module fabrication. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Global Rapid Flood Mapping System with Spaceborne SAR Data

    Science.gov (United States)

    Yun, S. H.; Owen, S. E.; Hua, H.; Agram, P. S.; Fattahi, H.; Liang, C.; Manipon, G.; Fielding, E. J.; Rosen, P. A.; Webb, F.; Simons, M.

    2017-12-01

    As part of the Advanced Rapid Imaging and Analysis (ARIA) project for Natural Hazards, at NASA's Jet Propulsion Laboratory and California Institute of Technology, we have developed an automated system that produces derived products for flood extent map generation using spaceborne SAR data. The system takes user's input of area of interest polygons and time window for SAR data search (pre- and post-event). Then the system automatically searches and downloads SAR data, processes them to produce coregistered SAR image pairs, and generates log amplitude ratio images from each pair. Currently the system is automated to support SAR data from the European Space Agency's Sentinel-1A/B satellites. We have used the system to produce flood extent maps from Sentinel-1 SAR data for the May 2017 Sri Lanka floods, which killed more than 200 people and displaced about 600,000 people. Our flood extent maps were delivered to the Red Cross to support response efforts. Earlier we also responded to the historic August 2016 Louisiana floods in the United States, which claimed 13 people's lives and caused over $10 billion property damage. For this event, we made synchronized observations from space, air, and ground in close collaboration with USGS and NOAA. The USGS field crews acquired ground observation data, and NOAA acquired high-resolution airborne optical imagery within the time window of +/-2 hours of the SAR data acquisition by JAXA's ALOS-2 satellite. The USGS coordinates of flood water boundaries were used to calibrate our flood extent map derived from the ALOS-2 SAR data, and the map was delivered to FEMA for estimating the number of households affected. Based on the lessons learned from this response effort, we customized the ARIA system automation for rapid flood mapping and developed a mobile friendly web app that can easily be used in the field for data collection. Rapid automatic generation of SAR-based global flood maps calibrated with independent observations from

  1. Genetic correlations between brain volumes and the WAIS-III dimensions of verbal comprehension, working memory, perceptual organization, and processing speed

    DEFF Research Database (Denmark)

    Posthuma, Daniëlle; Baare, Wim F.C.; Hulshoff Pol, Hilleke E.

    2003-01-01

    We recently showed that the correlation of gray and white matter volume with full scale IQ and the Working Memory dimension are completely mediated by common genetic factors (Posthuma et al., 2002). Here we examine whether the other WAIS III dimensions (Verbal Comprehension, Perceptual Organization......, Processing Speed) are also related to gray and white matter volume, and whether any of the dimensions are related to cerebellar volume. Two overlapping samples provided 135 subjects from 60 extended twin families for whom both MRI scans and WAIS III data were available. All three brain volumes are related...... to Working Memory capacity (r = 0.27). This phenotypic correlation is completely due to a common underlying genetic factor. Processing Speed was genetically related to white matter volume (r(g) = 0.39). Perceptual Organization was both genetically (r(g) = 0.39) and environmentally (r(e) = -0.71) related...

  2. Spaceborne Potential for Examining Taiga-Tundra Ecotone Form and Vulnerability

    Science.gov (United States)

    Montesano, Paul M.; Sun, Guoqing; Dubayah, Ralph O.; Ranson, K. Jon

    2016-01-01

    In the taiga-tundra ecotone (TTE), site-dependent forest structure characteristics can influence the subtle and heterogeneous structural changes that occur across the broad circumpolar extent. Such changes may be related to ecotone form, described by the horizontal and vertical patterns of forest structure (e.g., tree cover, density and height) within TTE forest patches, driven by local site conditions, and linked to ecotone dynamics. The unique circumstance of subtle, variable and widespread vegetation change warrants the application of spaceborne data including high-resolution (less than 5m) spaceborne imagery (HRSI) across broad scales for examining TTE form and predicting dynamics. This study analyzes forest structure at the patch-scale in the TTE to provide a means to examine both vertical and horizontal components of ecotone form. We demonstrate the potential of spaceborne data for integrating forest height and density to assess TTE form at the scale of forest patches across the circumpolar biome by (1) mapping forest patches in study sites along the TTE in northern Siberia with a multi-resolution suite of spaceborne data, and (2) examining the uncertainty of forest patch height from this suite of data across sites of primarily diffuse TTE forms. Results demonstrate the opportunities for improving patch-scale spaceborne estimates of forest height, the vertical component of TTE form, with HRSI. The distribution of relative maximum height uncertainty based on prediction intervals is centered at approximately 40%, constraining the use of height for discerning differences in forest patches. We discuss this uncertainty in light of a conceptual model of general ecotone forms, and highlight how the uncertainty of spaceborne estimates of height can contribute to the uncertainty in identifying TTE forms. A focus on reducing the uncertainty of height estimates in forest patches may improve depiction of TTE form, which may help explain variable forest responses in the

  3. What makes grassroots conservation organizations resilient? An empirical analysis of diversity, organizational memory, and the number of leaders.

    Science.gov (United States)

    Baral, Nabin

    2013-03-01

    Conservation Area Management Committees (CAMCs)-the functional decision-making units consisting entirely of local villagers-are grassroots organizations legally established to manage the Annapurna Conservation Area (ACA) in Nepal. These committees suffered due to the decade-long Maoist insurgency, but they survived. The paper attempts to test what factors contributed to their resiliency. For this, I surveyed 30 CAMCs during the summer of 2007 and conducted semi-structured interviews of 190 executive members of the CAMCs and 13 park officials who closely monitor the CAMCs. Regression results showed that the number of leaders (b = 0.44, t = 2.38, P = .027) was the most critical variable for building the resilience of CAMCs to the Maoist insurgency, i.e., retaining the same function, structure, and identity of the committees. As there were no reported conflicts among leaders and they were involved in negotiations and devising contingency plans, CAMCs actually benefited from having more leaders. Of the three diversity indices, the quadratic terms of age diversity (b = -5.42, t = 1.95, P = .064) and ethnic diversity (b = -4.05, t = 1.78, P = .075) had a negative impact on the CAMCs' resilience. Skill diversity and organizational memory had no significant influence on the CAMCs' resilience (t  .10). These results have important implications for building resilience in community-based conservation.

  4. High reliable and stable organic field-effect transistor nonvolatile memory with a poly(4-vinyl phenol) charge trapping layer based on a pn-heterojunction active layer

    Energy Technology Data Exchange (ETDEWEB)

    Xiang, Lanyi; Ying, Jun; Han, Jinhua; Zhang, Letian, E-mail: zlt@jlu.edu.cn, E-mail: wwei99@jlu.edu.cn; Wang, Wei, E-mail: zlt@jlu.edu.cn, E-mail: wwei99@jlu.edu.cn [State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012 (China)

    2016-04-25

    In this letter, we demonstrate a high reliable and stable organic field-effect transistor (OFET) based nonvolatile memory (NVM) with a polymer poly(4-vinyl phenol) (PVP) as the charge trapping layer. In the unipolar OFETs, the inreversible shifts of the turn-on voltage (V{sub on}) and severe degradation of the memory window (ΔV{sub on}) at programming (P) and erasing (E) voltages, respectively, block their application in NVMs. The obstacle is overcome by using a pn-heterojunction as the active layer in the OFET memory, which supplied a holes and electrons accumulating channel at the supplied P and E voltages, respectively. Both holes and electrons transferring from the channels to PVP layer and overwriting the trapped charges with an opposite polarity result in the reliable bidirectional shifts of V{sub on} at P and E voltages, respectively. The heterojunction OFET exhibits excellent nonvolatile memory characteristics, with a large ΔV{sub on} of 8.5 V, desired reading (R) voltage at 0 V, reliable P/R/E/R dynamic endurance over 100 cycles and a long retention time over 10 years.

  5. Episodic memory, semantic memory, and amnesia.

    Science.gov (United States)

    Squire, L R; Zola, S M

    1998-01-01

    Episodic memory and semantic memory are two types of declarative memory. There have been two principal views about how this distinction might be reflected in the organization of memory functions in the brain. One view, that episodic memory and semantic memory are both dependent on the integrity of medial temporal lobe and midline diencephalic structures, predicts that amnesic patients with medial temporal lobe/diencephalic damage should be proportionately impaired in both episodic and semantic memory. An alternative view is that the capacity for semantic memory is spared, or partially spared, in amnesia relative to episodic memory ability. This article reviews two kinds of relevant data: 1) case studies where amnesia has occurred early in childhood, before much of an individual's semantic knowledge has been acquired, and 2) experimental studies with amnesic patients of fact and event learning, remembering and knowing, and remote memory. The data provide no compelling support for the view that episodic and semantic memory are affected differently in medial temporal lobe/diencephalic amnesia. However, episodic and semantic memory may be dissociable in those amnesic patients who additionally have severe frontal lobe damage.

  6. Organizational memory: from expectations memory to procedural memory

    NARCIS (Netherlands)

    Ebbers, J.J.; Wijnberg, N.M.

    2009-01-01

    Organizational memory is not just the stock of knowledge about how to do things, but also of expectations of organizational members vis-à-vis each other and the organization as a whole. The central argument of this paper is that this second type of organizational memory -organizational expectations

  7. Design of a modular digital computer system, DRL 4. [for meeting future requirements of spaceborne computers

    Science.gov (United States)

    1972-01-01

    The design is reported of an advanced modular computer system designated the Automatically Reconfigurable Modular Multiprocessor System, which anticipates requirements for higher computing capacity and reliability for future spaceborne computers. Subjects discussed include: an overview of the architecture, mission analysis, synchronous and nonsynchronous scheduling control, reliability, and data transmission.

  8. On reconciling ground-based with spaceborne normalized radar cross section measurements

    DEFF Research Database (Denmark)

    Baumgartner, Francois; Munk, Jens; Jezek, K C

    2002-01-01

    This study examines differences in the normalized radar cross section, derived from ground-based versus spaceborne radar data. A simple homogeneous half-space model, indicates that agreement between the two improves as 1) the distance from the scatterer is increased; and/or 2) the extinction...

  9. Design considerations on a sparse array antenna for Ka-band spaceborne SAR applications

    NARCIS (Netherlands)

    Jacobs, S.; Bekers, D.; Monni, S.; Otten, M.; Van Rossum, W.; Gerini, G.; Germani, C.; Fortini, D.; Toso, G.

    2015-01-01

    This contribution addresses the problem of designing a sparse active array antenna for spaceborne SAR applications at Ka-band. The main driver for the design is limiting the recurring manufacturing costs associated to the number of active modules, while preserving main performance and insuring a

  10. Space-borne polarimetric SAR sensors or the golden age of radar polarimetry

    Directory of Open Access Journals (Sweden)

    Pottier E.

    2010-06-01

    Full Text Available SAR Polarimetry represents an active area of research in Active Earth Remote Sensing. This interest is clearly supported by the fact that nowadays there exists, or there will exist in a very next future, a non negligible quantity of launched Polarimetric SAR Spaceborne sensors. The ENVISAT satellite, developed by ESA, was launched on March 2002, and was the first Spaceborne sensor offering an innovative dualpolarization Advanced Synthetic Aperture Radar (ASAR system operating at C-band. The second Polarimetric Spaceborne sensor is ALOS, a Japanese Earth-Observation satellite, developed by JAXA and was launched in January 2006. This mission includes an active L-band polarimetric radar sensor (PALSAR whose highresolution data may be used for environmental and hazard monitoring. The third Polarimetric Spaceborne sensor is TerraSAR-X, a new German radar satellite, developed by DLR, EADS-Astrium and Infoterra GmbH, was launched on June 2007. This sensor carries a dual-polarimetric and high frequency X-Band SAR sensor that can be operated in different modes and offers features that were not available from space before. At least, the Polarimetric Spaceborne sensor, developed by CSA and MDA, and named RADARSAT-2 was launched in December 2007 The Radarsat program was born out the need for effective monitoring of Canada’s icy waters, and some Radarsat-2 capabilities that benefit sea- and river ice applications are the multi-polarization options that will improve ice-edge detection, ice-type discrimination and structure information. The many advances in these different Polarimetric Spaceborne platforms were developed to respond to specific needs for radar data in environmental monitoring applications around the world, like : sea- and river-ice monitoring, marine surveillance, disaster management, oil spill detection, snow monitoring, hydrology, mapping, geology, agriculture, soil characterisation, forestry applications (biomass, allometry, height

  11. Spaceborne potential for examining taiga-tundra ecotone form and vulnerability

    Science.gov (United States)

    Montesano, Paul M.; Sun, Guoqing; Dubayah, Ralph O.; Ranson, K. Jon

    2016-07-01

    In the taiga-tundra ecotone (TTE), site-dependent forest structure characteristics can influence the subtle and heterogeneous structural changes that occur across the broad circumpolar extent. Such changes may be related to ecotone form, described by the horizontal and vertical patterns of forest structure (e.g., tree cover, density, and height) within TTE forest patches, driven by local site conditions, and linked to ecotone dynamics. The unique circumstance of subtle, variable, and widespread vegetation change warrants the application of spaceborne data including high-resolution (ecotone form. We demonstrate the potential of spaceborne data for integrating forest height and density to assess TTE form at the scale of forest patches across the circumpolar biome by (1) mapping forest patches in study sites along the TTE in northern Siberia with a multi-resolution suite of spaceborne data and (2) examining the uncertainty of forest patch height from this suite of data across sites of primarily diffuse TTE forms. Results demonstrate the opportunities for improving patch-scale spaceborne estimates of forest height, the vertical component of TTE form, with HRSI. The distribution of relative maximum height uncertainty based on prediction intervals is centered at ˜ 40 %, constraining the use of height for discerning differences in forest patches. We discuss this uncertainty in light of a conceptual model of general ecotone forms and highlight how the uncertainty of spaceborne estimates of height can contribute to the uncertainty in identifying TTE forms. A focus on reducing the uncertainty of height estimates in forest patches may improve depiction of TTE form, which may help explain variable forest responses in the TTE to climate change and the vulnerability of portions of the TTE to forest structure change.

  12. [Supposed role of "metabolic memory" in formation of response reaction to stress-factors in young and adult organisms].

    Science.gov (United States)

    Bozhkov, A I; Dlubovskaia, V L; Dmitriev, Iu V; Meshaĭkina, N I; Maleev, V A; Klimova, E M

    2009-01-01

    The influence of the combined long-lasted influences of sulfur sulfate and diet restriction in young (3 month age) and adult (21 month age) Vistar rats on activity of glucose-6-phospatase, alaninaminotranspherase (ALT), aspartataminotranspherase (AST), and on phosphorilating activity of liver mitochondria was studied to investigate the role of metabolic memory on the peculiarities of response reaction. The young animals not differed from adult ones in the possibility of inducing activity of glucose-6-phospatase, ALT, and on phosphorilating activity after the influence of sulfur sulfate and diet restriction. The age-related differences in glucose-6-phospatase and transpherases and phosphorilating activity existing in control disappeared after the long-lasted action of sulfur sulfate and diet restriction. The answer reaction in enzyme activity to stress factors applied many times depends upon the metabolic memory formed in the process of adaptation, and the age of animals have no influence on it. In some relation the ontogenesis may be considered as a result of adaptation genesis. The metabolic memory can change the answer of the system to the stress influence. There are three types of modification of the answer to stress factors: the answer remains unchanged (metabolic memory), "paradox answer" formation, and super activation of the metabolic system.

  13. Change detection on LOD 2 building models with very high resolution spaceborne stereo imagery

    Science.gov (United States)

    Qin, Rongjun

    2014-10-01

    Due to the fast development of the urban environment, the need for efficient maintenance and updating of 3D building models is ever increasing. Change detection is an essential step to spot the changed area for data (map/3D models) updating and urban monitoring. Traditional methods based on 2D images are no longer suitable for change detection in building scale, owing to the increased spectral variability of the building roofs and larger perspective distortion of the very high resolution (VHR) imagery. Change detection in 3D is increasingly being investigated using airborne laser scanning data or matched Digital Surface Models (DSM), but rare study has been conducted regarding to change detection on 3D city models with VHR images, which is more informative but meanwhile more complicated. This is due to the fact that the 3D models are abstracted geometric representation of the urban reality, while the VHR images record everything. In this paper, a novel method is proposed to detect changes directly on LOD (Level of Detail) 2 building models with VHR spaceborne stereo images from a different date, with particular focus on addressing the special characteristics of the 3D models. In the first step, the 3D building models are projected onto a raster grid, encoded with building object, terrain object, and planar faces. The DSM is extracted from the stereo imagery by hierarchical semi-global matching (SGM). In the second step, a multi-channel change indicator is extracted between the 3D models and stereo images, considering the inherent geometric consistency (IGC), height difference, and texture similarity for each planar face. Each channel of the indicator is then clustered with the Self-organizing Map (SOM), with "change", "non-change" and "uncertain change" status labeled through a voting strategy. The "uncertain changes" are then determined with a Markov Random Field (MRF) analysis considering the geometric relationship between faces. In the third step, buildings are

  14. High-Sensitivity Semiconductor Photocathodes for Space-Born UV Photon-Counting and Imaging, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Many UV photon-counting and imaging applications, including space-borne astronomy, missile tracking and guidance, UV spectroscopy for chemical/biological...

  15. The Role of Shape in Semantic Memory Organization of Objects: An Experimental Study Using PI-Release.

    Science.gov (United States)

    van Weelden, Lisanne; Schilperoord, Joost; Swerts, Marc; Pecher, Diane

    2015-01-01

    Visual information contributes fundamentally to the process of object categorization. The present study investigated whether the degree of activation of visual information in this process is dependent on the contextual relevance of this information. We used the Proactive Interference (PI-release) paradigm. In four experiments, we manipulated the information by which objects could be categorized and subsequently be retrieved from memory. The pattern of PI-release showed that if objects could be stored and retrieved both by (non-perceptual) semantic and (perceptual) shape information, then shape information was overruled by semantic information. If, however, semantic information could not be (satisfactorily) used to store and retrieve objects, then objects were stored in memory in terms of their shape. The latter effect was found to be strongest for objects from identical semantic categories.

  16. Low-voltage operating flexible ferroelectric organic field-effect transistor nonvolatile memory with a vertical phase separation P(VDF-TrFE-CTFE)/PS dielectric

    Science.gov (United States)

    Xu, Meili; Xiang, Lanyi; Xu, Ting; Wang, Wei; Xie, Wenfa; Zhou, Dayu

    2017-10-01

    Future flexible electronic systems require memory devices combining low-power operation and mechanical bendability. However, high programming/erasing voltages, which are universally needed to switch the storage states in previously reported ferroelectric organic field-effect transistor (Fe-OFET) nonvolatile memories (NVMs), severely prevent their practical applications. In this work, we develop a route to achieve a low-voltage operating flexible Fe-OFET NVM. Utilizing vertical phase separation, an ultrathin self-organized poly(styrene) (PS) buffering layer covers the surface of the ferroelectric polymer layer by one-step spin-coating from their blending solution. The ferroelectric polymer with a low coercive field contributes to low-voltage operation in the Fe-OFET NVM. The polymer PS contributes to the improvement of mobility, attributing to screening the charge scattering and decreasing the surface roughness. As a result, a high performance flexible Fe-OFET NVM is achieved at the low P/E voltages of ±10 V, with a mobility larger than 0.2 cm2 V-1 s-1, a reliable P/E endurance over 150 cycles, stable data storage retention capability over 104 s, and excellent mechanical bending durability with a slight performance degradation after 1000 repetitive tensile bending cycles at a curvature radius of 5.5 mm.

  17. Genetic correlations between brain volumes and the WAIS-III dimensions of verbal comprehension, working memory, perceptual organization, and processing speed.

    Science.gov (United States)

    Posthuma, Daniëlle; Baaré, Wim F C; Hulshoff Pol, Hilleke E; Kahn, René S; Boomsma, Dorret I; De Geus, Eco J C

    2003-04-01

    We recently showed that the correlation of gray and white matter volume with full scale IQ and the Working Memory dimension are completely mediated by common genetic factors (Posthuma et al., 2002). Here we examine whether the other WAIS III dimensions (Verbal Comprehension, Perceptual Organization, Processing Speed) are also related to gray and white matter volume, and whether any of the dimensions are related to cerebellar volume. Two overlapping samples provided 135 subjects from 60 extended twin families for whom both MRI scans and WAIS III data were available. All three brain volumes are related to Working Memory capacity (r = 0.27). This phenotypic correlation is completely due to a common underlying genetic factor. Processing Speed was genetically related to white matter volume (r(g) = 0.39). Perceptual Organization was both genetically (r(g) = 0.39) and environmentally (r(e) = -0.71) related to cerebellar volume. Verbal Comprehension was not related to any of the three brain volumes. It is concluded that brain volumes are genetically related to intelligence which suggests that genes that influence brain volume may also be important for intelligence. It is also noted however, that the direction of causation (i.e., do genes influence brain volume which in turn influences intelligence, or alternatively, do genes influence intelligence which in turn influences brain volume), or the presence or absence of pleiotropy has not been resolved yet.

  18. A design study for an advanced ocean color scanner system. [spaceborne equipment

    Science.gov (United States)

    Kim, H. H.; Fraser, R. S.; Thompson, L. L.; Bahethi, O.

    1980-01-01

    Along with a colorimetric data analysis scheme, the instrumental parameters which need to be optimized in future spaceborne ocean color scanner systems are outlined. With regard to assessing atmospheric effects from ocean colorimetry, attention is given to computing size parameters of the aerosols in the atmosphere, total optical depth measurement, and the aerosol optical thickness. It is suggested that sensors based on the use of linear array technology will meet hardware objectives.

  19. Memory architecture

    NARCIS (Netherlands)

    2012-01-01

    A memory architecture is presented. The memory architecture comprises a first memory and a second memory. The first memory has at least a bank with a first width addressable by a single address. The second memory has a plurality of banks of a second width, said banks being addressable by components

  20. Facile fabrication of highly ordered poly(vinylidene fluoride-trifluoroethylene) nanodot arrays for organic ferroelectric memory

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Huajing [Department of Applied Physics, The Hong Kong Polytechnic University (PolyU) Hunghom, Kowloon (Hong Kong); Department of Chemistry, Tsinghua University, Beijing 100084 (China); Yan, Qingfeng, E-mail: yanqf@mail.tsinghua.edu.cn, E-mail: jiyan.dai@polyu.edu.hk; Geng, Chong; Li, Qiang [Department of Chemistry, Tsinghua University, Beijing 100084 (China); Chan, Ngai Yui; Au, Kit; Ng, Sheung Mei; Leung, Chi Wah; Wa Chan, Helen Lai; Dai, Jiyan, E-mail: yanqf@mail.tsinghua.edu.cn, E-mail: jiyan.dai@polyu.edu.hk [Department of Applied Physics, The Hong Kong Polytechnic University (PolyU) Hunghom, Kowloon (Hong Kong); Yao, Jianjun [Asylum Research, Oxford Instruments, Shanghai 200233 (China); Guo, Dong [Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190 (China)

    2016-01-07

    Nano-patterned ferroelectric materials have attracted significant attention as the presence of two or more thermodynamically equivalent switchable polarization states can be employed in many applications such as non-volatile memory. In this work, a simple and effective approach for fabrication of highly ordered poly(vinylidene fluoride–trifluoroethylene) P(VDF-TrFE) nanodot arrays is demonstrated. By using a soft polydimethylsiloxane mold, we successfully transferred the 2D array pattern from the initial monolayer of colloidal polystyrene nanospheres to the imprinted P(VDF-TrFE) films via nanoimprinting. The existence of a preferred orientation of the copolymer chain after nanoimprinting was confirmed by Fourier transform infrared spectra. Local polarization switching behavior was measured by piezoresponse force microscopy, and each nanodot showed well-formed hysteresis curve and butterfly loop with a coercive field of ∼62.5 MV/m. To illustrate the potential application of these ordered P(VDF-TrFE) nanodot arrays, the writing and reading process as non-volatile memory was demonstrated at a relatively low voltage. As such, our results offer a facile and promising route to produce arrays of ferroelectric polymer nanodots with improved piezoelectric functionality.

  1. Facile fabrication of highly ordered poly(vinylidene fluoride-trifluoroethylene) nanodot arrays for organic ferroelectric memory

    International Nuclear Information System (INIS)

    Fang, Huajing; Yan, Qingfeng; Geng, Chong; Li, Qiang; Chan, Ngai Yui; Au, Kit; Ng, Sheung Mei; Leung, Chi Wah; Wa Chan, Helen Lai; Dai, Jiyan; Yao, Jianjun; Guo, Dong

    2016-01-01

    Nano-patterned ferroelectric materials have attracted significant attention as the presence of two or more thermodynamically equivalent switchable polarization states can be employed in many applications such as non-volatile memory. In this work, a simple and effective approach for fabrication of highly ordered poly(vinylidene fluoride–trifluoroethylene) P(VDF-TrFE) nanodot arrays is demonstrated. By using a soft polydimethylsiloxane mold, we successfully transferred the 2D array pattern from the initial monolayer of colloidal polystyrene nanospheres to the imprinted P(VDF-TrFE) films via nanoimprinting. The existence of a preferred orientation of the copolymer chain after nanoimprinting was confirmed by Fourier transform infrared spectra. Local polarization switching behavior was measured by piezoresponse force microscopy, and each nanodot showed well-formed hysteresis curve and butterfly loop with a coercive field of ∼62.5 MV/m. To illustrate the potential application of these ordered P(VDF-TrFE) nanodot arrays, the writing and reading process as non-volatile memory was demonstrated at a relatively low voltage. As such, our results offer a facile and promising route to produce arrays of ferroelectric polymer nanodots with improved piezoelectric functionality

  2. Facile fabrication of highly ordered poly(vinylidene fluoride-trifluoroethylene) nanodot arrays for organic ferroelectric memory

    Science.gov (United States)

    Fang, Huajing; Yan, Qingfeng; Geng, Chong; Chan, Ngai Yui; Au, Kit; Yao, Jianjun; Ng, Sheung Mei; Leung, Chi Wah; Li, Qiang; Guo, Dong; Wa Chan, Helen Lai; Dai, Jiyan

    2016-01-01

    Nano-patterned ferroelectric materials have attracted significant attention as the presence of two or more thermodynamically equivalent switchable polarization states can be employed in many applications such as non-volatile memory. In this work, a simple and effective approach for fabrication of highly ordered poly(vinylidene fluoride-trifluoroethylene) P(VDF-TrFE) nanodot arrays is demonstrated. By using a soft polydimethylsiloxane mold, we successfully transferred the 2D array pattern from the initial monolayer of colloidal polystyrene nanospheres to the imprinted P(VDF-TrFE) films via nanoimprinting. The existence of a preferred orientation of the copolymer chain after nanoimprinting was confirmed by Fourier transform infrared spectra. Local polarization switching behavior was measured by piezoresponse force microscopy, and each nanodot showed well-formed hysteresis curve and butterfly loop with a coercive field of ˜62.5 MV/m. To illustrate the potential application of these ordered P(VDF-TrFE) nanodot arrays, the writing and reading process as non-volatile memory was demonstrated at a relatively low voltage. As such, our results offer a facile and promising route to produce arrays of ferroelectric polymer nanodots with improved piezoelectric functionality.

  3. Memory mass storage

    CERN Document Server

    Campardo, Giovanni; Iaculo, Massimo

    2011-01-01

    Covering all the fundamental storage technologies such as semiconductor, magnetic, optical and uncommon, this volume details their core characteristics. In addition, it includes an overview of the 'biological memory' of the human brain and its organization.

  4. Electrical bistabilities and memory mechanisms of nonvolatile organic bistable devices based on exfoliated muscovite-type mica nanoparticle/poly(methylmethacrylate) nanocomposites

    Science.gov (United States)

    Lim, Won Gyu; Lee, Dea Uk; Na, Han Gil; Kim, Hyoun Woo; Kim, Tae Whan

    2018-02-01

    Organic bistable devices (OBDs) with exfoliated mica nanoparticles (NPs) embedded into an insulating poly(methylmethacrylate) (PMMA) layer were fabricated by using a spin-coating method. Current-voltage (I-V) curves for the Al/PMMA/exfoliated mica NP/PMMA/indium-tin-oxide/glass devices at 300 K showed a clockwise current hysteresis behavior due to the existence of the exfoliated muscovite-type mica NPs, which is an essential feature for bistable devices. Write-read-erase-read data showed that the OBDs had rewritable nonvolatile memories and an endurance number of ON/OFF switching for the OBDs of 102 cycles. An ON/OFF ratio of 1 × 103 was maintained for retention times larger than 1 × 104 s. The memory mechanisms of the fabricated OBDs were described by using the trapping and the tunneling processes within a PMMA active layer containing exfoliated muscovite-type mica NPs on the basis of the energy band diagram and the I-V curves.

  5. Structured Memory for Neural Turing Machines

    OpenAIRE

    Zhang, Wei; Yu, Yang; Zhou, Bowen

    2015-01-01

    Neural Turing Machines (NTM) contain memory component that simulates "working memory" in the brain to store and retrieve information to ease simple algorithms learning. So far, only linearly organized memory is proposed, and during experiments, we observed that the model does not always converge, and overfits easily when handling certain tasks. We think memory component is key to some faulty behaviors of NTM, and better organization of memory component could help fight those problems. In this...

  6. Neural organization of linguistic short-term memory is sensory modality-dependent: evidence from signed and spoken language.

    Science.gov (United States)

    Pa, Judy; Wilson, Stephen M; Pickell, Herbert; Bellugi, Ursula; Hickok, Gregory

    2008-12-01

    Despite decades of research, there is still disagreement regarding the nature of the information that is maintained in linguistic short-term memory (STM). Some authors argue for abstract phonological codes, whereas others argue for more general sensory traces. We assess these possibilities by investigating linguistic STM in two distinct sensory-motor modalities, spoken and signed language. Hearing bilingual participants (native in English and American Sign Language) performed equivalent STM tasks in both languages during functional magnetic resonance imaging. Distinct, sensory-specific activations were seen during the maintenance phase of the task for spoken versus signed language. These regions have been previously shown to respond to nonlinguistic sensory stimulation, suggesting that linguistic STM tasks recruit sensory-specific networks. However, maintenance-phase activations common to the two languages were also observed, implying some form of common process. We conclude that linguistic STM involves sensory-dependent neural networks, but suggest that sensory-independent neural networks may also exist.

  7. Spaceborne profiling of atmospheric temperature and particle extinction with pure rotational Raman lidar and of relative humidity in combination with differential absorption lidar: performance simulations

    International Nuclear Information System (INIS)

    Di Girolamo, Paolo; Behrendt, Andreas; Wulfmeyer, Volker

    2006-01-01

    The performance of a spaceborne temperature lidar based on the pure rotational Raman (RR) technique in the UV has been simulated. Results show that such a system deployed onboard a low-Earth-orbit satellite would provide global-scale clear-sky temperature measurements in the troposphere and lower stratosphere with precisions that satisfy World Meteorological Organization (WMO) threshold observational requirements for numerical weather prediction and climate research applications. Furthermore, nighttime temperature measurements would still be within the WMO threshold observational requirements in the presence of several cloud structures. The performance of aerosol extinction measurements from space, which can be carried out simultaneously with temperature measurements by RR lidar, is also assessed. Furthermore, we discuss simulations of relative humidity measurements from space obtained from RR temperature measurements and water-vapor data measured with the differential absorption lidar (DIAL) technique

  8. Organics.

    Science.gov (United States)

    Chian, Edward S. K.; DeWalle, Foppe B.

    1978-01-01

    Presents water analysis literature for 1978. This review is concerned with organics, and it covers: (1) detergents and surfactants; (2) aliphatic and aromatic hydrocarbons; (3) pesticides and chlorinated hydrocarbons; and (4) naturally occurring organics. A list of 208 references is also presented. (HM)

  9. Organizers.

    Science.gov (United States)

    Callison, Daniel

    2000-01-01

    Focuses on "organizers," tools or techniques that provide identification and classification along with possible relationships or connections among ideas, concepts, and issues. Discusses David Ausubel's research and ideas concerning advance organizers; the implications of Ausubel's theory to curriculum and teaching; "webbing," a…

  10. Advancing Atmosphere-Ocean Remote Sensing with Spaceborne High Spectral Resolution Lidar

    Science.gov (United States)

    Hostetler, C. A.; Behrenfeld, M. J.; Chepfer, H.; Hu, Y.; Hair, J. W.; Trepte, C. R.; Winker, D. M.; Ferrare, R. A.; Burton, S. P.; Scarino, A. J.; Powell, K. A.; Michaud, J.

    2016-12-01

    More than 1600 publications employing observations from the CALIOP lidar on CALIPSO testify to the value of spaceborne lidar for aerosol and cloud remote sensing. Recent publications have shown the value of CALIOP data for retrievals of key ocean carbon cycle stocks. In this presentation we focus on the advantages of a more advanced technique, High Spectral Resolution Lidar (HSRL), for aerosol, cloud, and ocean remote sensing. An atmosphere-ocean optimized HSRL achieves greater accuracy over the standard backscatter lidar technique for retrievals of aerosol and cloud extinction and backscatter profiles, provides additional capability to retrieve aerosol and cloud microphysical parameters, and enables vertically-resolved characterization of scattering and absorption properties of suspended and dissolved materials in the ocean. Numerous publications highlight the synergy of coincident CALIOP and passive A-train observations for studies of aerosol-cloud radiative effects and cloud-climate feedback. Less appreciated is the complementarity that would exist between an optimized spaceborne lidar and passive ocean color. An optimized HSRL flown in formation with the Plankton, Aerosol, and ocean Ecosystem (PACE) mission would provide phytoplankton vertical distribution, which is needed for accurately estimating net primary productivity but absent in the PACE ocean color data. The HSRL would also provide data needed to improve atmospheric correction schemes in ocean color retrievals. Because lidar provides measurements both night and day, through tenuous clouds and aerosol layers, and in holes between clouds, the sampling achieved is highly complementary to passive radiometry, providing data in important high latitude regions where ocean color data are sparse or nonexistent. In this presentation we will discuss 1) relevant aerosol, cloud, and ocean retrievals from airborne HSRL field missions; 2) the advantages of an optimized spaceborne HSRL for aerosol, cloud, and ocean

  11. Research on the space-borne coherent wind lidar technique and the prototype experiment

    Science.gov (United States)

    Gao, Long; Tao, Yuliang; An, Chao; Yang, Jukui; Du, Guojun; Zheng, Yongchao

    2016-10-01

    Space-borne coherent wind lidar technique is considered as one of the most promising and appropriate remote Sensing methods for successfully measuring the whole global vector wind profile between the lower atmosphere and the middle atmosphere. Compared with other traditional methods, the space-borne coherent wind lidar has some advantages, such as, the all-day operation; many lidar systems can be integrated into the same satellite because of the light-weight and the small size, eye-safe wavelength, and being insensitive to the background light. Therefore, this coherent lidar could be widely applied into the earth climate research, disaster monitoring, numerical weather forecast, environment protection. In this paper, the 2μm space-borne coherent wind lidar system for measuring the vector wind profile is proposed. And the technical parameters about the sub-system of the coherent wind lidar are simulated and the all sub-system schemes are proposed. For sake of validating the technical parameters of the space-borne coherent wind lidar system and the optical off-axis telescope, the weak laser signal detection technique, etc. The proto-type coherent wind lidar is produced and the experiments for checking the performance of this proto-type coherent wind lidar are finished with the hard-target and the soft target, and the horizontal wind and the vertical wind profile are measured and calibrated, respectively. For this proto-type coherent wind lidar, the wavelength is 1.54μm, the pulse energy 80μJ, the pulse width 300ns, the diameter of the off-axis telescope 120mm, the single wedge for cone scanning with the 40°angle, and the two dualbalanced InGaAs detector modules are used. The experiment results are well consisted with the simulation process, and these results show that the wind profile between the vertical altitude 4km can be measured, the accuracy of the wind velocity and the wind direction are better than 1m/s and +/-10°, respectively.

  12. Particle transport simulation for spaceborne, NaI gamma-ray spectrometers

    International Nuclear Information System (INIS)

    Dyer, C.S.; Truscott, P.R.; Sims, A.J.; Comber, C.; Hammond, N.D.A.

    1988-11-01

    Radioactivity induced in detectors by protons and secondary neutrons limits the sensitivity of spaceborne gamma-ray spectrometers. Three dimensional Monte Carlo transport codes have been employed to simulate particle transport of cosmic rays and inner-belt protons in various representations of the Gamma Ray Observatory Spacecraft and the Oriented Scintillation Spectrometer Experiment. Results are used to accurately quantify the contributions to the radioactive background, assess shielding options and examine the effect of detector and space-craft orientation in anisotropic trapped proton fluxes. (author)

  13. The concentration principle applied to spaceborne solar arrays. AGORA mission: Studies synthesis

    Science.gov (United States)

    Laget, R.

    1986-01-01

    Studies that led to selection of the distributed 25 kW SARA LOUVRE concept for the solar cell generator to be flown on the AGORA asteroid mission, and the major characteristics of such a spaceborne solar array are summarized. In the SARA LOUVRE concept, a parabolic cross section reflector concentrates incident light over the rear face of the identical, preceding reflector dish. The whole set of reflectors is pivotally commanded, thus compensating the effects of depointing. Geometric concentration factor is 10. End of life power level at 2.5 AU is 4.5 kW.

  14. Remote sensing of high-latitude ionization profiles by ground-based and spaceborne instrumentation

    International Nuclear Information System (INIS)

    Vondrak, R.R.

    1981-01-01

    Ionospheric specification and modeling are now largely based on data provided by active remote sensing with radiowave techniques (ionosondes, incoherent-scatter radars, and satellite beacons). More recently, passive remote sensing techniques have been developed that can be used to monitor quantitatively the spatial distribution of high-latitude E-region ionization. These passive methods depend on the measurement, or inference, of the energy distribution of precipitating kilovolt electrons, the principal source of the nighttime E-region at high latitudes. To validate these techniques, coordinated measurements of the auroral ionosphere have been made with the Chatanika incoherent-scatter radar and a variety of ground-based and spaceborne sensors

  15. Tests of the gravitational redshift effect in space-born and ground-based experiments

    Science.gov (United States)

    Vavilova, I. B.

    2018-02-01

    This paper provides a brief overview of experiments as concerns with the tests of the gravitational redshift (GRS) effect in ground-based and space-born experiments. In particular, we consider the GRS effects in the gravitational field of the Earth, the major planets of the Solar system, compact stars (white dwarfs and neutron stars) where this effect is confirmed with a higher accuracy. We discuss availabilities to confirm the GRS effect for galaxies and galaxy clusters in visible and X-ray ranges of the electromagnetic spectrum.

  16. Application of spaceborne SAR data to uranium metallogenetic environment, condition and prognosis

    International Nuclear Information System (INIS)

    Huang Xianfang; Huang Shutao; Dong Wenming; Pan Wei; Fang Maolong; Xuan Yanxiu

    2001-01-01

    JERS-1 SAR data processing and data fusion with TM, airborne radioactive and magnetic survey data have been elaborated and image effects have been described in the paper. By means of the analysis of the processed images, the stratigraphy, structures (including faults and folds) and ore-controlling factors in the study area have successfully been interpreted; the underground water mobile characteristics have been discussed; and the metallogenetic environment and condition have been summarized. Based on above research results, the prospecting criteria have been provided and favorable sections have been suggested. The practice has indicated that the application of spaceborne SAR data to uranium reconnaissance and exploration has potential prospects

  17. FIR and sub-mm direct detection spectrometers for spaceborne astronomy

    Science.gov (United States)

    Wijnbergen, Jan J.; de Graauw, Thijs

    1990-12-01

    Candidate spaceborne sub-mm instrumentation proposed for space projects with large passively cooled telescopes are reviewed. Grating instruments and Fourier transform spectroscopy (FTS) spectrometers are discussed. Particular attention is given to imaging Fabry-Perot spectrometers. The special needs of the Large Deployable Reflector (LDR) and for the Far InfraRed Space Telescope (FIRST) missions in this area are outlined. Possible Fabry-Perot spectrometer setups are diagrammed and outlined. The use of spherical and multiplex Fabry-Perot spectrometers is discussed.

  18. An Optimal Beamforming Algorithm for Phased-Array Antennas Used in Multi-Beam Spaceborne Radiometers

    DEFF Research Database (Denmark)

    Iupikov, O. A.; Ivashina, M. V.; Pontoppidan, K.

    2015-01-01

    Strict requirements for future spaceborne ocean missions using multi-beam radiometers call for new antenna technologies, such as digital beamforming phased arrays. In this paper, we present an optimal beamforming algorithm for phased-array antenna systems designed to operate as focal plane arrays...... to a FPA feeding a torus reflector antenna (designed under the contract with the European Space Agency) and tested for multiple beams. The results demonstrate an improved performance in terms of the optimized beam characteristics, yielding much higher spatial and radiometric resolution as well as much...

  19. MEMORY MODULATION

    Science.gov (United States)

    Roozendaal, Benno; McGaugh, James L.

    2011-01-01

    Our memories are not all created equally strong: Some experiences are well remembered while others are remembered poorly, if at all. Research on memory modulation investigates the neurobiological processes and systems that contribute to such differences in the strength of our memories. Extensive evidence from both animal and human research indicates that emotionally significant experiences activate hormonal and brain systems that regulate the consolidation of newly acquired memories. These effects are integrated through noradrenergic activation of the basolateral amygdala which regulates memory consolidation via interactions with many other brain regions involved in consolidating memories of recent experiences. Modulatory systems not only influence neurobiological processes underlying the consolidation of new information, but also affect other mnemonic processes, including memory extinction, memory recall and working memory. In contrast to their enhancing effects on consolidation, adrenal stress hormones impair memory retrieval and working memory. Such effects, as with memory consolidation, require noradrenergic activation of the basolateral amygdala and interactions with other brain regions. PMID:22122145

  20. Memory Matters

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Memory Matters KidsHealth / For Kids / Memory Matters What's in ... of your complex and multitalented brain. What Is Memory? When an event happens, when you learn something, ...

  1. Spatial working memory in immersive virtual reality foraging: path organization, traveling distance and search efficiency in humans (Homo sapiens).

    Science.gov (United States)

    De Lillo, Carlo; Kirby, Melissa; James, Frances C

    2014-05-01

    Search and serial recall tasks were used in the present study to characterize the factors affecting the ability of humans to keep track of a set of spatial locations while traveling in an immersive virtual reality foraging environment. The first experiment required the exhaustive exploration of a set of locations following a procedure previously used with other primate and non-primate species to assess their sensitivity to the geometric arrangement of foraging sites. The second experiment assessed the dependency of search performance on search organization by requiring the participants to recall specific trajectories throughout the foraging space. In the third experiment, the distance between the foraging sites was manipulated in order to contrast the effects of organization and traveling distance on recall accuracy. The results show that humans benefit from the use of organized search patterns when attempting to monitor their travel though either a clustered "patchy" space or a matrix of locations. Their ability to recall a series of locations is dependent on whether the order in which they are explored conformed or did not conform to specific organization principles. Moreover, the relationship between search efficiency and search organization is not confounded by effects of traveling distance. These results indicate that in humans, organizational factors may play a large role in their ability to forage efficiently. The extent to which such dependency may pertain to other primates and could be accounted for by visual organization processes is discussed on the basis of previous studies focused on perceptual grouping, search, and serial recall in non-human species. © 2013 Wiley Periodicals, Inc.

  2. Recognition of abstract objects via neural oscillators: interaction among topological organization, associative memory and gamma band synchronization.

    Science.gov (United States)

    Ursino, Mauro; Magosso, Elisa; Cuppini, Cristiano

    2009-02-01

    Synchronization of neural activity in the gamma band is assumed to play a significant role not only in perceptual processing, but also in higher cognitive functions. Here, we propose a neural network of Wilson-Cowan oscillators to simulate recognition of abstract objects, each represented as a collection of four features. Features are ordered in topological maps of oscillators connected via excitatory lateral synapses, to implement a similarity principle. Experience on previous objects is stored in long-range synapses connecting the different topological maps, and trained via timing dependent Hebbian learning (previous knowledge principle). Finally, a downstream decision network detects the presence of a reliable object representation, when all features are oscillating in synchrony. Simulations performed giving various simultaneous objects to the network (from 1 to 4), with some missing and/or modified properties suggest that the network can reconstruct objects, and segment them from the other simultaneously present objects, even in case of deteriorated information, noise, and moderate correlation among the inputs (one common feature). The balance between sensitivity and specificity depends on the strength of the Hebbian learning. Achieving a correct reconstruction in all cases, however, requires ad hoc selection of the oscillation frequency. The model represents an attempt to investigate the interactions among topological maps, autoassociative memory, and gamma-band synchronization, for recognition of abstract objects.

  3. Organizations

    DEFF Research Database (Denmark)

    Hatch, Mary Jo

    and considers many more. Mary Jo Hatch introduces the concept of organizations by presenting definitions and ideas drawn from the a variety of subject areas including the physical sciences, economics, sociology, psychology, anthropology, literature, and the visual and performing arts. Drawing on examples from......Most of us recognize that organizations are everywhere. You meet them on every street corner in the form of families and shops, study in them, work for them, buy from them, pay taxes to them. But have you given much thought to where they came from, what they are today, and what they might become...... prehistory and everyday life, from the animal kingdom as well as from business, government, and other formal organizations, Hatch provides a lively and thought provoking introduction to the process of organization....

  4. Development of reaction-sintered SiC mirror for space-borne optics

    Science.gov (United States)

    Yui, Yukari Y.; Kimura, Toshiyoshi; Tange, Yoshio

    2017-11-01

    We are developing high-strength reaction-sintered silicon carbide (RS-SiC) mirror as one of the new promising candidates for large-diameter space-borne optics. In order to observe earth surface or atmosphere with high spatial resolution from geostationary orbit, larger diameter primary mirrors of 1-2 m are required. One of the difficult problems to be solved to realize such optical system is to obtain as flat mirror surface as possible that ensures imaging performance in infrared - visible - ultraviolet wavelength region. This means that homogeneous nano-order surface flatness/roughness is required for the mirror. The high-strength RS-SiC developed and manufactured by TOSHIBA is one of the most excellent and feasible candidates for such purpose. Small RS-SiC plane sample mirrors have been manufactured and basic physical parameters and optical performances of them have been measured. We show the current state of the art of the RS-SiC mirror and the feasibility of a large-diameter RS-SiC mirror for space-borne optics.

  5. Studies of Bagley Icefield during surge and Black Rapids Glacier, Alaska, using spaceborne SAR interferometry

    Science.gov (United States)

    Fatland, Dennis Robert

    1998-12-01

    This thesis presents studies of two temperate valley glaciers---Bering Glacier in the Chugach-St.Elias Mountains, South Central Alaska, and Black Rapids Glacier in the Alaska Range, Interior Alaska---using differential spaceborne radar interferometry. The first study was centered on the 1993--95 surge of Bering Glacier and the resultant ice dynamics on its accumulation area, the Bagley Icefield. The second study site was chosen for purposes of comparison of the interferometry results with conventional field measurements, particularly camera survey data and airborne laser altimetry. A comprehensive suite of software was written to interferometrically process synthetic aperture radar (SAR) data in order to derive estimates of surface elevation and surface velocity on these subject glaciers. In addition to these results, the data revealed unexpected but fairly common concentric rings called 'phase bull's-eyes', image features typically 0.5 to 4 km in diameter located over the central part of various glaciers. These bull's-eyes led to a hypothetical model in which they were interpreted to indicate transitory instances of high subglacial water pressure that locally lift the glacier from its bed by several centimeters. This model is associated with previous findings about the nature of glacier bed hydrology and glacier surging. In addition to the dynamical analysis presented herein, this work is submitted as a contribution to the ongoing development of spaceborne radar interferometry as a glaciological tool.

  6. The Characterization of a DIRSIG Simulation Environment to Support the Inter-Calibration of Spaceborne Sensors

    Science.gov (United States)

    Ambeau, Brittany L.; Gerace, Aaron D.; Montanaro, Matthew; McCorkel, Joel

    2016-01-01

    Climate change studies require long-term, continuous records that extend beyond the lifetime, and the temporal resolution, of a single remote sensing satellite sensor. The inter-calibration of spaceborne sensors is therefore desired to provide spatially, spectrally, and temporally homogeneous datasets. The Digital Imaging and Remote Sensing Image Generation (DIRSIG) tool is a first principle-based synthetic image generation model that has the potential to characterize the parameters that impact the accuracy of the inter-calibration of spaceborne sensors. To demonstrate the potential utility of the model, we compare the radiance observed in real image data to the radiance observed in simulated image from DIRSIG. In the present work, a synthetic landscape of the Algodones Sand Dunes System is created. The terrain is facetized using a 2-meter digital elevation model generated from NASA Goddard's LiDAR, Hyperspectral, and Thermal (G-LiHT) imager. The material spectra are assigned using hyperspectral measurements of sand collected from the Algodones Sand Dunes System. Lastly, the bidirectional reflectance distribution function (BRDF) properties are assigned to the modeled terrain using the Moderate Resolution Imaging Spectroradiometer (MODIS) BRDF product in conjunction with DIRSIG's Ross-Li capability. The results of this work indicate that DIRSIG is in good agreement with real image data. The potential sources of residual error are identified and the possibilities for future work are discussed..

  7. Hybrid Geometric Calibration Method for Multi-Platform Spaceborne SAR Image with Sparse Gcps

    Science.gov (United States)

    Lv, G.; Tang, X.; Ai, B.; Li, T.; Chen, Q.

    2018-04-01

    Geometric calibration is able to provide high-accuracy geometric coordinates of spaceborne SAR image through accurate geometric parameters in the Range-Doppler model by ground control points (GCPs). However, it is very difficult to obtain GCPs that covering large-scale areas, especially in the mountainous regions. In addition, the traditional calibration method is only used for single platform SAR images and can't support the hybrid geometric calibration for multi-platform images. To solve the above problems, a hybrid geometric calibration method for multi-platform spaceborne SAR images with sparse GCPs is proposed in this paper. First, we calibrate the master image that contains GCPs. Secondly, the point tracking algorithm is used to obtain the tie points (TPs) between the master and slave images. Finally, we calibrate the slave images using TPs as the GCPs. We take the Beijing-Tianjin- Hebei region as an example to study SAR image hybrid geometric calibration method using 3 TerraSAR-X images, 3 TanDEM-X images and 5 GF-3 images covering more than 235 kilometers in the north-south direction. Geometric calibration of all images is completed using only 5 GCPs. The GPS data extracted from GNSS receiver are used to assess the plane accuracy after calibration. The results after geometric calibration with sparse GCPs show that the geometric positioning accuracy is 3 m for TSX/TDX images and 7.5 m for GF-3 images.

  8. The characterization of a DIRSIG simulation environment to support the inter-calibration of spaceborne sensors

    Science.gov (United States)

    Ambeau, Brittany L.; Gerace, Aaron D.; Montanaro, Matthew; McCorkel, Joel

    2016-09-01

    Climate change studies require long-term, continuous records that extend beyond the lifetime, and the temporal resolution, of a single remote sensing satellite sensor. The inter-calibration of spaceborne sensors is therefore desired to provide spatially, spectrally, and temporally homogeneous datasets. The Digital Imaging and Remote Sensing Image Generation (DIRSIG) tool is a first principle-based synthetic image generation model that has the potential to characterize the parameters that impact the accuracy of the inter-calibration of spaceborne sensors. To demonstrate the potential utility of the model, we compare the radiance observed in real image data to the radiance observed in simulated image from DIRSIG. In the present work, a synthetic landscape of the Algodones Sand Dunes System is created. The terrain is facetized using a 2-meter digital elevation model generated from NASA Goddard's LiDAR, Hyperspectral, and Thermal (G-LiHT) imager. The material spectra are assigned using hyperspectral measurements of sand collected from the Algodones Sand Dunes System. Lastly, the bidirectional reflectance distribution function (BRDF) properties are assigned to the modeled terrain using the Moderate Resolution Imaging Spectroradiometer (MODIS) BRDF product in conjunction with DIRSIG's Ross-Li capability. The results of this work indicate that DIRSIG is in good agreement with real image data. The potential sources of residual error are identified and the possibilities for future work are discussed.

  9. Emotion and Autobiographical Memory

    Directory of Open Access Journals (Sweden)

    Nuray Sarp

    2011-09-01

    Full Text Available Self and mind are constituted with the cumulative effects of significant life events. This description is regarded as a given explicitly or implicitly in vari-ous theories of personality. Such an acknowledgment inevitably brings together these theories on two basic concepts. The first one is the emotions that give meaning to experiences and the second one is the memory which is related to the storage of these experiences. The part of the memory which is responsible for the storage and retrieval of life events is the autobiographical memory. Besides the development of personality, emotions and autobiographical memory are important in the development of and maintenance of psychopathology. Therefore, these two concepts have both longitudinal and cross-sectional functions in understanding human beings. In case of psychopathology, understanding emotions and autobiographical memory developmentally, aids in understanding the internal susceptibility factors. In addition, understanding how these two structures work and influence each other in an acute event would help to understand the etiological mechanisms of mental disorders. In the literature, theories that include both of these structures and that have clinical implications, are inconclusive. Theories on memory generally focus on cognitive and semantic structures while neglecting emotions, whereas theories on emotions generally neglect memory and its organization. There are only a few theories that cover both of these two concepts. In the present article, these theories that include both emotions and autobiographical memory in the same framework (i.e. Self Memory System, Associative Network Theory, Structural and Contextual theories and Affect Regulation Theory were discussed to see the full picture. Taken together, these theories seem to have the potential to suggest data-driven models in understanding and explaining symptoms such as flashbacks, dissociation, amnesia, over general memory seen in

  10. Time-Predictable Virtual Memory

    DEFF Research Database (Denmark)

    Puffitsch, Wolfgang; Schoeberl, Martin

    2016-01-01

    Virtual memory is an important feature of modern computer architectures. For hard real-time systems, memory protection is a particularly interesting feature of virtual memory. However, current memory management units are not designed for time-predictability and therefore cannot be used...... in such systems. This paper investigates the requirements on virtual memory from the perspective of hard real-time systems and presents the design of a time-predictable memory management unit. Our evaluation shows that the proposed design can be implemented efficiently. The design allows address translation...... and address range checking in constant time of two clock cycles on a cache miss. This constant time is in strong contrast to the possible cost of a miss in a translation look-aside buffer in traditional virtual memory organizations. Compared to a platform without a memory management unit, these two additional...

  11. Single-Mode, High Repetition Rate, Compact Ho:YLF Laser for Space-Borne Lidar Applications

    Science.gov (United States)

    Bai, Yingxin; Yu, Jirong; Wong, Teh-Hwa; Chen, Songsheng; Petros, Mulugeta; Singh, Upendra N.

    2014-01-01

    A single transverse/longitudinal mode, compact Q-switched Ho:YLF laser has been designed and demonstrated for space-borne lidar applications. The pulse energy is between 34-40 mJ for 100-200 Hz operation. The corresponding peak power is >1 MW.

  12. Integrated active fire retrievals and biomass burning emissions using complementary near-coincident ground, airborne and spaceborne sensor data

    Science.gov (United States)

    Wilfrid Schroeder; Evan Ellicott; Charles Ichoku; Luke Ellison; Matthew B. Dickinson; Roger D. Ottmar; Craig Clements; Dianne Hall; Vincent Ambrosia; Robert. Kremens

    2013-01-01

    Ground, airborne and spaceborne data were collected for a 450 ha prescribed fire implemented on 18 October 2011 at the Henry W. Coe State Park in California. The integration of various data elements allowed near-coincident active fire retrievals to be estimated. The Autonomous Modular Sensor-Wildfire (AMS) airborne multispectral imaging system was used as a bridge...

  13. Development of transition edge superconducting bolometers for the SAFARI Far-Infrared spectrometer on the SPICA space-borne telescope

    NARCIS (Netherlands)

    Mauskopf, P.; Morozov, D.; Glowacka, D.; Goldie, D.; Withington, S.; Bruijn, M.; De Korte, P.; Hoevers, H.; Ridder, M.; Van der Kuur, J.; Gao, J.R.

    2008-01-01

    We describe the optimization of transition edge superconducting (TES) detectors for use in a far-infrared (FIR) Fourier transform spectrometer (FTS) mounted on a cryogenically cooled space-borne telescope (e.g. SPICA). The required noise equivalent power (NEP) of the detectors is approximately 10?19

  14. Using memory-efficient algorithm for large-scale time-domain modeling of surface plasmon polaritons propagation in organic light emitting diodes

    Science.gov (United States)

    Zakirov, Andrey; Belousov, Sergei; Valuev, Ilya; Levchenko, Vadim; Perepelkina, Anastasia; Zempo, Yasunari

    2017-10-01

    We demonstrate an efficient approach to numerical modeling of optical properties of large-scale structures with typical dimensions much greater than the wavelength of light. For this purpose, we use the finite-difference time-domain (FDTD) method enhanced with a memory efficient Locally Recursive non-Locally Asynchronous (LRnLA) algorithm called DiamondTorre and implemented for General Purpose Graphical Processing Units (GPGPU) architecture. We apply our approach to simulation of optical properties of organic light emitting diodes (OLEDs), which is an essential step in the process of designing OLEDs with improved efficiency. Specifically, we consider a problem of excitation and propagation of surface plasmon polaritons (SPPs) in a typical OLED, which is a challenging task given that SPP decay length can be about two orders of magnitude greater than the wavelength of excitation. We show that with our approach it is possible to extend the simulated volume size sufficiently so that SPP decay dynamics is accounted for. We further consider an OLED with periodically corrugated metallic cathode and show how the SPP decay length can be greatly reduced due to scattering off the corrugation. Ultimately, we compare the performance of our algorithm to the conventional FDTD and demonstrate that our approach can efficiently be used for large-scale FDTD simulations with the use of only a single GPGPU-powered workstation, which is not practically feasible with the conventional FDTD.

  15. AN ASSESSMENT OF SPACEBORNE NEAR-NADIR INTERFEROMETRIC SAR PERFORMANCE OVER INLAND WATERS WITH REAL

    Directory of Open Access Journals (Sweden)

    H. Tan

    2018-04-01

    Full Text Available Elevation measurements of the continental water surface have been poorly collected with in situ measurements or occasionally with conventional altimeters with low accuracy. Techniques using InSAR at near-nadir angles to measure the inland water elevation with large swath and with high accuracy have been proposed, for instance, the WSOA on Jason 2 and the KaRIn on SWOT. However, the WSOA was abandoned unfortunately and the SWOT is planned to be launched in 2021. In this paper, we show real acquisitions of the first spaceborne InSAR of such kind, the Interferometric Imaging Radar Altimeter (InIRA, which has been working on Tiangong II spacecraft since 2016. We used the 90-m SRTM DEM as a reference to estimate the phase offset, and then an empirical calibration model was used to correct the baseline errors.

  16. An Assessment of Spaceborne Near-Nadir Interferometric SAR Performance Over Inland Waters with Real

    Science.gov (United States)

    Tan, H.; Li, S. Y.; Liu, Z. W.

    2018-04-01

    Elevation measurements of the continental water surface have been poorly collected with in situ measurements or occasionally with conventional altimeters with low accuracy. Techniques using InSAR at near-nadir angles to measure the inland water elevation with large swath and with high accuracy have been proposed, for instance, the WSOA on Jason 2 and the KaRIn on SWOT. However, the WSOA was abandoned unfortunately and the SWOT is planned to be launched in 2021. In this paper, we show real acquisitions of the first spaceborne InSAR of such kind, the Interferometric Imaging Radar Altimeter (InIRA), which has been working on Tiangong II spacecraft since 2016. We used the 90-m SRTM DEM as a reference to estimate the phase offset, and then an empirical calibration model was used to correct the baseline errors.

  17. Functional requirements for an intelligent RPC. [remote power controller for spaceborne electrical distribution system

    Science.gov (United States)

    Aucoin, B. M.; Heller, R. P.

    1990-01-01

    An intelligent remote power controller (RPC) based on microcomputer technology can implement advanced functions for the accurate and secure detection of all types of faults on a spaceborne electrical distribution system. The intelligent RPC will implement conventional protection functions such as overcurrent, under-voltage, and ground fault protection. Advanced functions for the detection of soft faults, which cannot presently be detected, can also be implemented. Adaptive overcurrent protection changes overcurrent settings based on connected load. Incipient and high-impedance fault detection provides early detection of arcing conditions to prevent fires, and to clear and reconfigure circuits before soft faults progress to a hard-fault condition. Power electronics techniques can be used to implement fault current limiting to prevent voltage dips during hard faults. It is concluded that these techniques will enhance the overall safety and reliability of the distribution system.

  18. Innovative operating modes and techniques for the spaceborne imaging radar-C instrument

    Science.gov (United States)

    Huneycutt, Bryan L.

    1990-01-01

    The operation of the spaceborne imaging radar-C (SIR-C) is discussed. The SIR-C instrument has been designed to obtain simultaneous multifrequency and simultaneous multipolarization radar images from a low earth orbit. It is a multiparameter imaging radar which will be flown during at least two different seasons. The instrument has been designed to operate in innovative modes such as the squint alignment mode, the extended aperture mode, the scansar mode, and the interferometry mode. The instrument has been designed to demonstrate innovative engineering techniques such as beam nulling for echo tracking, pulse-repetition frquency hopping for Doppler centroid tracking, generating the frequency step chirp for radar parameter flexibility, block floating point quantizing for data rate compression, and elevation beamwidth broadening for increasing the swath illumination.

  19. Research on Synthetic Aperture Radar Processing for the Spaceborne Sliding Spotlight Mode.

    Science.gov (United States)

    Shen, Shijian; Nie, Xin; Zhang, Xinggan

    2018-02-03

    Gaofen-3 (GF-3) is China' first C-band multi-polarization synthetic aperture radar (SAR) satellite, which also provides the sliding spotlight mode for the first time. Sliding-spotlight mode is a novel mode to realize imaging with not only high resolution, but also wide swath. Several key technologies for sliding spotlight mode in spaceborne SAR with high resolution are investigated in this paper, mainly including the imaging parameters, the methods of velocity estimation and ambiguity elimination, and the imaging algorithms. Based on the chosen Convolution BackProjection (CBP) and PFA (Polar Format Algorithm) imaging algorithms, a fast implementation method of CBP and a modified PFA method suitable for sliding spotlight mode are proposed, and the processing flows are derived in detail. Finally, the algorithms are validated by simulations and measured data.

  20. Research on Synthetic Aperture Radar Processing for the Spaceborne Sliding Spotlight Mode

    Directory of Open Access Journals (Sweden)

    Shijian Shen

    2018-02-01

    Full Text Available Gaofen-3 (GF-3 is China’ first C-band multi-polarization synthetic aperture radar (SAR satellite, which also provides the sliding spotlight mode for the first time. Sliding-spotlight mode is a novel mode to realize imaging with not only high resolution, but also wide swath. Several key technologies for sliding spotlight mode in spaceborne SAR with high resolution are investigated in this paper, mainly including the imaging parameters, the methods of velocity estimation and ambiguity elimination, and the imaging algorithms. Based on the chosen Convolution BackProjection (CBP and PFA (Polar Format Algorithm imaging algorithms, a fast implementation method of CBP and a modified PFA method suitable for sliding spotlight mode are proposed, and the processing flows are derived in detail. Finally, the algorithms are validated by simulations and measured data.

  1. Identification of sea ice types in spaceborne synthetic aperture radar data

    Science.gov (United States)

    Kwok, Ronald; Rignot, Eric; Holt, Benjamin; Onstott, R.

    1992-01-01

    This study presents an approach for identification of sea ice types in spaceborne SAR image data. The unsupervised classification approach involves cluster analysis for segmentation of the image data followed by cluster labeling based on previously defined look-up tables containing the expected backscatter signatures of different ice types measured by a land-based scatterometer. Extensive scatterometer observations and experience accumulated in field campaigns during the last 10 yr were used to construct these look-up tables. The classification approach, its expected performance, the dependence of this performance on radar system performance, and expected ice scattering characteristics are discussed. Results using both aircraft and simulated ERS-1 SAR data are presented and compared to limited field ice property measurements and coincident passive microwave imagery. The importance of an integrated postlaunch program for the validation and improvement of this approach is discussed.

  2. Coincident Observation of Lightning using Spaceborne Spectrophotometer and Ground-Level Electromagnetic Sensors

    Science.gov (United States)

    Adachi, Toru; Cohen, Morris; Li, Jingbo; Cummer, Steve; Blakeslee, Richard; Marshall, THomas; Stolzenberg, Maribeth; Karunarathne, Sumedhe; Hsu, Rue-Ron; Su, Han-Tzong; hide

    2012-01-01

    The present study aims at assessing a possible new way to reveal the properties of lightning flash, using spectrophotometric data obtained by FORMOSAT-2/ISUAL which is the first spaceborne multicolor lightning detector. The ISUAL data was analyzed in conjunction with ground ]based electromagnetic data obtained by Duke magnetic field sensors, NLDN, North Alabama Lightning Mapping Array (LMA), and Kennedy Space Center (KSC) electric field antennas. We first classified the observed events into cloud ]to ]ground (CG) and intra ]cloud (IC) lightning based on the Duke and NLDN measurements and analyzed ISUAL data to clarify their optical characteristics. It was found that the ISUAL optical waveform of CG lightning was strongly correlated with the current moment waveform, suggesting that it is possible to evaluate the electrical properties of lightning from satellite optical measurement to some extent. The ISUAL data also indicated that the color of CG lightning turned to red at the time of return stroke while the color of IC pulses remained unchanged. Furthermore, in one CG event which was simultaneously detected by ISUAL and LMA, the observed optical emissions slowly turned red as the altitude of optical source gradually decreased. All of these results indicate that the color of lightning flash depends on the source altitude and suggest that spaceborne optical measurement could be a new tool to discriminate CG and IC lightning. In the presentation, we will also show results on the comparison between the ISUAL and KSC electric field data to clarify characteristics of each lightning process such as preliminary breakdown, return stroke, and subsequent upward illumination.

  3. Electromagnetic modelling of a space-borne far-infrared interferometer

    Science.gov (United States)

    Donohoe, Anthony; O'Sullivan, Créidhe; Murphy, J. Anthony; Bracken, Colm; Savini, Giorgio; Pascale, Enzo; Ade, Peter; Sudiwala, Rashmi; Hornsby, Amber

    2016-02-01

    In this paper I will describe work done as part of an EU-funded project `Far-infrared space interferometer critical assessment' (FISICA). The aim of the project is to investigate science objectives and technology development required for the next generation THz space interferometer. The THz/FIR is precisely the spectral region where most of the energy from stars, exo-planetary systems and galaxy clusters deep in space is emitted. The atmosphere is almost completely opaque in the wave-band of interest so any observation that requires high quality data must be performed with a space-born instrument. A space-borne far infrared interferometer will be able to answer a variety of crucial astrophysical questions such as how do planets and stars form, what is the energy engine of most galaxies and how common are the molecule building blocks of life. The FISICA team have proposed a novel instrument based on a double Fourier interferometer that is designed to resolve the light from an extended scene, spectrally and spatially. A laboratory prototype spectral-spatial interferometer has been constructed to demonstrate the feasibility of the double-Fourier technique at far infrared wavelengths (0.15 - 1 THz). This demonstrator is being used to investigate and validate important design features and data-processing methods for future instruments. Using electromagnetic modelling techniques several issues related to its operation at long baselines and wavelengths, such as diffraction, have been investigated. These are critical to the design of the concept instrument and the laboratory testbed.

  4. Airborne Radar Observations of Severe Hailstorms: Implications for Future Spaceborne Radar

    Science.gov (United States)

    Heymsfield, Gerald M.; Tian, Lin; Li, Lihua; McLinden, Matthew; Cervantes, Jaime I.

    2013-01-01

    A new dual-frequency (Ku and Ka band) nadir-pointing Doppler radar on the high-altitude NASA ER-2 aircraft, called the High-Altitude Imaging Wind and Rain Airborne Profiler (HIWRAP), has collected data over severe thunderstorms in Oklahoma and Kansas during the Midlatitude Continental Convective Clouds Experiment (MC3E). The overarching motivation for this study is to understand the behavior of the dualwavelength airborne radar measurements in a global variety of thunderstorms and how these may relate to future spaceborne-radar measurements. HIWRAP is operated at frequencies that are similar to those of the precipitation radar on the Tropical Rainfall Measuring Mission (Ku band) and the upcoming Global Precipitation Measurement mission satellite's dual-frequency (Ku and Ka bands) precipitation radar. The aircraft measurements of strong hailstorms have been combined with ground-based polarimetric measurements to obtain a better understanding of the response of the Ku- and Ka-band radar to the vertical distribution of the hydrometeors, including hail. Data from two flight lines on 24 May 2011 are presented. Doppler velocities were approx. 39m/s2at 10.7-km altitude from the first flight line early on 24 May, and the lower value of approx. 25m/s on a second flight line later in the day. Vertical motions estimated using a fall speed estimate for large graupel and hail suggested that the first storm had an updraft that possibly exceeded 60m/s for the more intense part of the storm. This large updraft speed along with reports of 5-cm hail at the surface, reflectivities reaching 70 dBZ at S band in the storm cores, and hail signals from polarimetric data provide a highly challenging situation for spaceborne-radar measurements in intense convective systems. The Ku- and Ka-band reflectivities rarely exceed approx. 47 and approx. 37 dBZ, respectively, in these storms.

  5. English/Russian terminology on radiometric calibration of space-borne optoelectronic sensors

    Science.gov (United States)

    Privalsky, V.; Zakharenkov, V.; Humpherys, T.; Sapritsky, V.; Datla, R.

    The efficient use of data acquired through exo-atmospheric observations of the Earth within the framework of existing and newly planned programs requires a unique understanding of respective terms and definitions. Yet, the last large-scale document on the subject - The International Electrotechnical Vocabulary - had been published 18 years ago. This lack of a proper document, which would reflect the changes that had occurred in the area since that time, is especially detrimental to the developing international efforts aimed at global observations of the Earth from space such as the Global Earth Observations Program proposed by the U.S.A. at the 2003 WMO Congress. To cover this gap at least partially, a bi-lingual explanatory dictionary of terms and definitions in the area of radiometric calibration of space-borne IR sensors is developed. The objectives are to produce a uniform terminology for the global space-borne observations of the Earth, establish a unique understanding of terms and definitions by the radiometric communities, including a correspondence between the Russian and American terms and definitions, and to develop a formal English/Russian reference dictionary for use by scientists and engineers involved in radiometric observations of the Earth from space. The dictionary includes close to 400 items covering basic concepts of geometric, wave and corpuscular optics, remote sensing technologies, and ground-based calibration as well as more detailed treatment of terms and definitions in the areas of radiometric quantities, symbols and units, optical phenomena and optical properties of objects and media, and radiometric systems and their properties. The dictionary contains six chapters: Basic Concepts, Quantities, Symbols, and Units, Optical phenomena, Optical characteristics of surfaces and media, Components of Radiometric Systems, Characteristics of radiometric system components, plus English/Russian and Russian/Inglish indices.

  6. New Processing of Spaceborne Imaging Radar-C (SIR-C) Data

    Science.gov (United States)

    Meyer, F. J.; Gracheva, V.; Arko, S. A.; Labelle-Hamer, A. L.

    2017-12-01

    The Spaceborne Imaging Radar-C (SIR-C) was a radar system, which successfully operated on two separate shuttle missions in April and October 1994. During these two missions, a total of 143 hours of radar data were recorded. SIR-C was the first multifrequency and polarimetric spaceborne radar system, operating in dual frequency (L- and C- band) and with quad-polarization. SIR-C had a variety of different operating modes, which are innovative even from today's point of view. Depending on the mode, it was possible to acquire data with different polarizations and carrier frequency combinations. Additionally, different swaths and bandwidths could be used during the data collection and it was possible to receive data with two antennas in the along-track direction.The United States Geological Survey (USGS) distributes the synthetic aperture radar (SAR) images as single-look complex (SLC) and multi-look complex (MLC) products. Unfortunately, since June 2005 the SIR-C processor has been inoperable and not repairable. All acquired SLC and MLC images were processed with a course resolution of 100 m with the goal of generating a quick look. These images are however not well suited for scientific analysis. Only a small percentage of the acquired data has been processed as full resolution SAR images and the unprocessed high resolution data cannot be processed any more at the moment.At the Alaska Satellite Facility (ASF) a new processor was developed to process binary SIR-C data to full resolution SAR images. ASF is planning to process the entire recoverable SIR-C archive to full resolution SLCs, MLCs and high resolution geocoded image products. ASF will make these products available to the science community through their existing data archiving and distribution system.The final paper will describe the new processor and analyze the challenges of reprocessing the SIR-C data.

  7. Cognitive memory.

    Science.gov (United States)

    Widrow, Bernard; Aragon, Juan Carlos

    2013-05-01

    Regarding the workings of the human mind, memory and pattern recognition seem to be intertwined. You generally do not have one without the other. Taking inspiration from life experience, a new form of computer memory has been devised. Certain conjectures about human memory are keys to the central idea. The design of a practical and useful "cognitive" memory system is contemplated, a memory system that may also serve as a model for many aspects of human memory. The new memory does not function like a computer memory where specific data is stored in specific numbered registers and retrieval is done by reading the contents of the specified memory register, or done by matching key words as with a document search. Incoming sensory data would be stored at the next available empty memory location, and indeed could be stored redundantly at several empty locations. The stored sensory data would neither have key words nor would it be located in known or specified memory locations. Sensory inputs concerning a single object or subject are stored together as patterns in a single "file folder" or "memory folder". When the contents of the folder are retrieved, sights, sounds, tactile feel, smell, etc., are obtained all at the same time. Retrieval would be initiated by a query or a prompt signal from a current set of sensory inputs or patterns. A search through the memory would be made to locate stored data that correlates with or relates to the prompt input. The search would be done by a retrieval system whose first stage makes use of autoassociative artificial neural networks and whose second stage relies on exhaustive search. Applications of cognitive memory systems have been made to visual aircraft identification, aircraft navigation, and human facial recognition. Concerning human memory, reasons are given why it is unlikely that long-term memory is stored in the synapses of the brain's neural networks. Reasons are given suggesting that long-term memory is stored in DNA or RNA

  8. Memory Modulation

    NARCIS (Netherlands)

    Roozendaal, Benno; McGaugh, James L.

    2011-01-01

    Our memories are not all created equally strong: Some experiences are well remembered while others are remembered poorly, if at all. Research on memory modulation investigates the neurobiological processes and systems that contribute to such differences in the strength of our memories. Extensive

  9. Traces of Drosophila Memory

    Science.gov (United States)

    Davis, Ronald L.

    2012-01-01

    Summary Studies using functional cellullar imaging of living flies have identified six memory traces that form in the olfactory nervous system after conditioning with odors. These traces occur in distinct nodes of the olfactory nervous system, form and disappear across different windows of time, and are detected in the imaged neurons as increased calcium influx or synaptic release in response to the conditioned odor. Three traces form at, or near acquisition and co-exist with short-term behavioral memory. One trace forms with a delay after learning and co-exists with intermediate-term behavioral memory. Two traces form many hours after acquisition and co-exist with long-term behavioral memory. The transient memory traces may support behavior across the time-windows of their existence. The experimental approaches for dissecting memory formation in the fly, ranging from the molecular to the systems, make it an ideal system for dissecting the logic by which the nervous system organizes and stores different temporal forms of memory. PMID:21482352

  10. Memory Dysfunction

    Science.gov (United States)

    Matthews, Brandy R.

    2015-01-01

    Purpose of Review: This article highlights the dissociable human memory systems of episodic, semantic, and procedural memory in the context of neurologic illnesses known to adversely affect specific neuroanatomic structures relevant to each memory system. Recent Findings: Advances in functional neuroimaging and refinement of neuropsychological and bedside assessment tools continue to support a model of multiple memory systems that are distinct yet complementary and to support the potential for one system to be engaged as a compensatory strategy when a counterpart system fails. Summary: Episodic memory, the ability to recall personal episodes, is the subtype of memory most often perceived as dysfunctional by patients and informants. Medial temporal lobe structures, especially the hippocampal formation and associated cortical and subcortical structures, are most often associated with episodic memory loss. Episodic memory dysfunction may present acutely, as in concussion; transiently, as in transient global amnesia (TGA); subacutely, as in thiamine deficiency; or chronically, as in Alzheimer disease. Semantic memory refers to acquired knowledge about the world. Anterior and inferior temporal lobe structures are most often associated with semantic memory loss. The semantic variant of primary progressive aphasia (svPPA) is the paradigmatic disorder resulting in predominant semantic memory dysfunction. Working memory, associated with frontal lobe function, is the active maintenance of information in the mind that can be potentially manipulated to complete goal-directed tasks. Procedural memory, the ability to learn skills that become automatic, involves the basal ganglia, cerebellum, and supplementary motor cortex. Parkinson disease and related disorders result in procedural memory deficits. Most memory concerns warrant bedside cognitive or neuropsychological evaluation and neuroimaging to assess for specific neuropathologies and guide treatment. PMID:26039844

  11. Declarative memory.

    Science.gov (United States)

    Riedel, Wim J; Blokland, Arjan

    2015-01-01

    Declarative Memory consists of memory for events (episodic memory) and facts (semantic memory). Methods to test declarative memory are key in investigating effects of potential cognition-enhancing substances--medicinal drugs or nutrients. A number of cognitive performance tests assessing declarative episodic memory tapping verbal learning, logical memory, pattern recognition memory, and paired associates learning are described. These tests have been used as outcome variables in 34 studies in humans that have been described in the literature in the past 10 years. Also, the use of episodic tests in animal research is discussed also in relation to the drug effects in these tasks. The results show that nutritional supplementation of polyunsaturated fatty acids has been investigated most abundantly and, in a number of cases, but not all, show indications of positive effects on declarative memory, more so in elderly than in young subjects. Studies investigating effects of registered anti-Alzheimer drugs, cholinesterase inhibitors in mild cognitive impairment, show positive and negative effects on declarative memory. Studies mainly carried out in healthy volunteers investigating the effects of acute dopamine stimulation indicate enhanced memory consolidation as manifested specifically by better delayed recall, especially at time points long after learning and more so when drug is administered after learning and if word lists are longer. The animal studies reveal a different picture with respect to the effects of different drugs on memory performance. This suggests that at least for episodic memory tasks, the translational value is rather poor. For the human studies, detailed parameters of the compositions of word lists for declarative memory tests are discussed and it is concluded that tailored adaptations of tests to fit the hypothesis under study, rather than "off-the-shelf" use of existing tests, are recommended.

  12. Tracking morphological changes and slope instability using spaceborne and ground-based SAR data

    Science.gov (United States)

    Di Traglia, Federico; Nolesini, Teresa; Ciampalini, Andrea; Solari, Lorenzo; Frodella, William; Bellotti, Fernando; Fumagalli, Alfio; De Rosa, Giuseppe; Casagli, Nicola

    2018-01-01

    Stromboli (Aeolian Archipelago, Italy) is an active volcano that is frequently affected by moderate to large mass wasting, which has occasionally triggered tsunamis. With the aim of understanding the relationship between the geomorphologic evolution and slope instability of Stromboli, remote sensing information from space-born Synthetic Aperture Radar (SAR) change detection and interferometry (InSAR) () and Ground Based InSAR (GBInSAR) was compared with field observations and morphological analyses. Ground reflectivity and SqueeSAR™ (an InSAR algorithm for surface deformation monitoring) displacement measurements from X-band COSMO-SkyMed satellites (CSK) were analysed together with displacement measurements from a permanent-sited, Ku-band GBInSAR system. Remote sensing results were compared with a preliminary morphological analysis of the Sciara del Fuoco (SdF) steep volcanic flank, which was carried out using a high-resolution Digital Elevation Model (DEM). Finally, field observations, supported by infrared thermographic surveys (IRT), allowed the interpretation and validation of remote sensing data. The analysis of the entire dataset (collected between January 2010 and December 2014) covers a period characterized by a low intensity of Strombolian activity. This period was punctuated by the occurrence of lava overflows, occurring from the crater terrace evolving downslope toward SdF, and flank eruptions, such as the 2014 event. The amplitude of the CSK images collected between February 22nd, 2010, and December 18th, 2014, highlights that during periods characterized by low-intensity Strombolian activity, the production of materials ejected from the crater terrace towards the SdF is generally low, and erosion is the prevailing process mainly affecting the central sector of the SdF. CSK-SqueeSAR™ and GBInSAR data allowed the identification of low displacements in the SdF, except for high displacement rates (up to 1.5 mm/h) that were measured following both lava

  13. Development of Spaceborne Radar Simulator by NICT and JAXA using JMA Cloud-resolving Model

    Science.gov (United States)

    Kubota, T.; Eito, H.; Aonashi, K.; Hashimoto, A.; Iguchi, T.; Hanado, H.; Shimizu, S.; Yoshida, N.; Oki, R.

    2009-12-01

    We are developing synthetic spaceborne radar data toward a simulation of the Dual-frequency Precipitation Radar (DPR) aboard the Global Precipitation Measurement (GPM) core-satellite. Our purposes are a production of test-bed data for higher level DPR algorithm developers, in addition to a diagnosis of a cloud resolving model (CRM). To make the synthetic data, we utilize the CRM by the Japan Meteorological Agency (JMA-NHM) (Ikawa and Saito 1991, Saito et al. 2006, 2007), and the spaceborne radar simulation algorithm by the National Institute of Information and Communications Technology (NICT) and the Japan Aerospace Exploration Agency (JAXA) named as the Integrated Satellite Observation Simulator for Radar (ISOSIM-Radar). The ISOSIM-Radar simulates received power data in a field of view of the spaceborne radar with consideration to a scan angle of the radar (Oouchi et al. 2002, Kubota et al. 2009). The received power data are computed with gaseous and hydrometeor attenuations taken into account. The backscattering and extinction coefficients are calculated assuming the Mie approximation for all species. The dielectric constants for solid particles are computed by the Maxwell-Garnett model (Bohren and Battan 1982). Drop size distributions are treated in accordance with those of the JMA-NHM. We assume a spherical sea surface, a Gaussian antenna pattern, and 49 antenna beam directions for scan angles from -17 to 17 deg. in the PR. In this study, we report the diagnosis of the JMA-NHM with reference to the TRMM Precipitation Radar (PR) and CloudSat Cloud Profiling Radar (CPR) using the ISOSIM-Radar from the view of comparisons in cloud microphysics schemes of the JMA-NHM. We tested three kinds of explicit bulk microphysics schemes based on Lin et al. (1983), that is, three-ice 1-moment scheme, three-ice 2-moment scheme (Eito and Aonashi 2009), and newly developed four-ice full 2-moment scheme (Hashimoto 2008). The hydrometeor species considered here are rain, graupel

  14. Quantum memory Quantum memory

    Science.gov (United States)

    Le Gouët, Jean-Louis; Moiseev, Sergey

    2012-06-01

    Interaction of quantum radiation with multi-particle ensembles has sparked off intense research efforts during the past decade. Emblematic of this field is the quantum memory scheme, where a quantum state of light is mapped onto an ensemble of atoms and then recovered in its original shape. While opening new access to the basics of light-atom interaction, quantum memory also appears as a key element for information processing applications, such as linear optics quantum computation and long-distance quantum communication via quantum repeaters. Not surprisingly, it is far from trivial to practically recover a stored quantum state of light and, although impressive progress has already been accomplished, researchers are still struggling to reach this ambitious objective. This special issue provides an account of the state-of-the-art in a fast-moving research area that makes physicists, engineers and chemists work together at the forefront of their discipline, involving quantum fields and atoms in different media, magnetic resonance techniques and material science. Various strategies have been considered to store and retrieve quantum light. The explored designs belong to three main—while still overlapping—classes. In architectures derived from photon echo, information is mapped over the spectral components of inhomogeneously broadened absorption bands, such as those encountered in rare earth ion doped crystals and atomic gases in external gradient magnetic field. Protocols based on electromagnetic induced transparency also rely on resonant excitation and are ideally suited to the homogeneous absorption lines offered by laser cooled atomic clouds or ion Coulomb crystals. Finally off-resonance approaches are illustrated by Faraday and Raman processes. Coupling with an optical cavity may enhance the storage process, even for negligibly small atom number. Multiple scattering is also proposed as a way to enlarge the quantum interaction distance of light with matter. The

  15. Spaceborne Remote Sensing of Aerosol Type: Global Distribution, Model Evaluation and Translation into Chemical Speciation

    Science.gov (United States)

    Kacenelenbogen, M. S.; Tan, Q.; Johnson, M. S.; Burton, S. P.; Redemann, J.; Hasekamp, O. P.; Dawson, K. W.; Hair, J. W.; Ferrare, R. A.; Butler, C. F.; Holben, B. N.; Beyersdorf, A. J.; Ziemba, L. D.; Froyd, K. D.; Dibb, J. E.; Shingler, T.; Sorooshian, A.; Jimenez, J. L.; Campuzano Jost, P.; Jacob, D.; Kim, P. S.; Travis, K.; Lacagnina, C.

    2016-12-01

    It is essential to evaluate and refine aerosol classification methods applied to passive satellite remote sensing. We have developed an aerosol classification algorithm (called Specified Clustering and Mahalanobis Classification, SCMC) that assigns an aerosol type to multi-parameter retrievals by spaceborne, airborne or ground-based passive remote sensing instruments [1]. The aerosol types identified by our scheme are pure dust, polluted dust, urban-industrial/developed economy, urban-industrial/developing economy, dark biomass smoke, light biomass smoke and pure marine. We apply the SCMC method to inversions from the ground-based AErosol RObotic NETwork (AERONET [2]) and retrievals from the space-borne Polarization and Directionality of Earth's Reflectances instrument (POLDER, [3]). The POLDER retrievals that we use differ from the standard POLDER retrievals [4] as they make full use of multi-angle, multispectral polarimetric data [5]. We analyze agreement in the aerosol types inferred from both AERONET and POLDER and evaluate GEOS-Chem [6] simulations over the globe. Finally, we use in-situ observations from the SEAC4RS airborne field experiment to bridge the gap between remote sensing-inferred qualitative SCMC aerosol types and their corresponding quantitative chemical speciation. We apply the SCMC method to airborne in-situ observations from the NASA Langley Aerosol Research Group Experiment (LARGE, [7]) and the Differential Aerosol Sizing and Hygroscopicity Spectrometer Probe (DASH-SP, [8]) instruments; we then relate each coarsely defined SCMC type to a sum of percentage of individual aerosol species, using in-situ observations from the Particle Analysis by Laser Mass Spectrometry (PALMS, [9]), the Soluble Acidic Gases and Aerosol (SAGA, [10]), and the High - Resolution Time - of - Flight Aerosol Mass Spectrometer (HR ToF AMS, [11]). [1] Russell P. B., et al., JGR, 119.16 (2014) [2] Holben B. N., et al., RSE, 66.1 (1998) [3] Tanré D., et al., AMT, 4.7 (2011

  16. A Memory-based Robot Architecture based on Contextual Information

    OpenAIRE

    Pratama, Ferdian; Mastrogiovanni, Fulvio; Chong, Nak Young

    2014-01-01

    In this paper, we present a preliminary conceptual design for a robot long-term memory architecture based on the notion of context. Contextual information is used to organize the data flow between Working Memory (including Perceptual Memory) and Long-Term Memory components. We discuss the major influence of the notion of context within Episodic Memory on Semantic and Procedural Memory, respectively. We address how the occurrence of specific object-related events in time impacts on the semanti...

  17. The Cognitive Neuroscience of Human Memory Since H.M

    OpenAIRE

    Squire, Larry R.; Wixted, John T.

    2011-01-01

    Work with patient H.M., beginning in the 1950s, established key principles about the organization of memory that inspired decades of experimental work. Since H.M., the study of human memory and its disorders has continued to yield new insights and to improve understanding of the structure and organization of memory. Here we review this work with emphasis on the neuroanatomy of medial temporal lobe and diencephalic structures important for memory, multiple memory systems, visual perception, im...

  18. The neurobiology of the human memory.

    Science.gov (United States)

    Fietta, Pierluigi; Fietta, Pieranna

    2011-01-01

    Memory can be defined as the ability to acquire, process, store, and retrieve information. Memory is indispensable for learning, adaptation, and survival of every living organism. In humans, the remembering process has acquired great flexibility and complexity, reaching close links with other mental functions, such as thinking and emotions. Changes in synaptic connectivity and interactions among multiple neural networks provide the neurobiological substrates for memory encoding, retention, and consolidation. Memory may be categorized as short-term and long-term memory (according to the storage temporal duration), as implicit and explicit memory (with respect to the consciousness of remembering), as declarative (knowing that [fact]) and procedural (knowing how [skill]) memory, or as sensory (echoic, iconic and haptil), semantic, and episodic memory (according to the various remembering domains). Significant advances have been obtained in understanding memory neurobiology, but much remains to be learned in its cognitive, psychological, and phenomenological aspects.

  19. Evaluating Land-Atmosphere Moisture Feedbacks in Earth System Models With Spaceborne Observations

    Science.gov (United States)

    Levine, P. A.; Randerson, J. T.; Lawrence, D. M.; Swenson, S. C.

    2016-12-01

    We have developed a set of metrics for measuring the feedback loop between the land surface moisture state and the atmosphere globally on an interannual time scale. These metrics consider both the forcing of terrestrial water storage (TWS) on subsequent atmospheric conditions as well as the response of TWS to antecedent atmospheric conditions. We designed our metrics to take advantage of more than one decade's worth of satellite observations of TWS from the Gravity Recovery and Climate Experiment (GRACE) along with atmospheric variables from the Atmospheric Infrared Sounder (AIRS), the Global Precipitation Climatology Project (GPCP), and Clouds and the Earths Radiant Energy System (CERES). Metrics derived from spaceborne observations were used to evaluate the strength of the feedback loop in the Community Earth System Model (CESM) Large Ensemble (LENS) and in several models that contributed simulations to Phase 5 of the Coupled Model Intercomparison Project (CMIP5). We found that both forcing and response limbs of the feedback loop were generally stronger in tropical and temperate regions in CMIP5 models and even more so in LENS compared to satellite observations. Our analysis suggests that models may overestimate the strength of the feedbacks between the land surface and the atmosphere, which is consistent with previous studies conducted across different spatial and temporal scales.

  20. Spaceborne Applications of P Band Imaging Radars for Measuring Forest Biomass

    Science.gov (United States)

    Rignot, Eric J.; Zimmermann, Reiner; vanZyl, Jakob J.

    1995-01-01

    In three sites of boreal and temperate forests, P band HH, HV, and VV polarization data combined estimate total aboveground dry woody biomass within 12 to 27% of the values derived from allometric equations, depending on forest complexity. Biomass estimates derived from HV-polarization data only are 2 to 14% less accurate. When the radar operates at circular polarization, the errors exceed 100% over flooded forests, wet or damaged trees and sparse open tall forests because double-bounce reflections of the radar signals yield radar signatures similar to that of tall and massive forests. Circular polarizations, which minimize the effect of Faraday rotation in spaceborne applications, are therefore of limited use for measuring forest biomass. In the tropical rain forest of Manu, in Peru, where forest biomass ranges from 4 kg/sq m in young forest succession up to 50 kg/sq m in old, undisturbed floodplain stands, the P band horizontal and vertical polarization data combined separate biomass classes in good agreement with forest inventory estimates. The worldwide need for large scale, updated, biomass estimates, achieved with a uniformly applied method, justifies a more in-depth exploration of multi-polarization long wavelength imaging radar applications for tropical forests inventories.

  1. A spaceborne inventory of volcanic activity in Antarctica and southern oceans, 2000-10

    Science.gov (United States)

    Patrick, Matthew R.; Smellie, John L.

    2015-01-01

    Of the more than twenty historically active volcanoes in Antarctica and the sub-Antarctic region only two, to our knowledge, host any ground-based monitoring instruments. Moreover, because of their remoteness, most of the volcanoes are seldom visited, thus relegating the monitoring of volcanism in this region almost entirely to satellites. In this study, high temporal resolution satellite data from the Hawaii Institute of Geophysics and Planetology's MODVOLC system using MODIS (Moderate Resolution Imaging Spectroradiometer) are complemented with high spatial resolution data (ASTER, or Advanced Spaceborne Thermal Emission and Reflection Radiometer, and similar sensors) to document volcanic activity throughout the region during the period 2000–10. Five volcanoes were observed in eruption (Mount Erebus, Mount Belinda, Mount Michael, Heard Island and McDonald Island), which were predominantly low-level and effusive in nature. Mount Belinda produced tephra, building a cinder cone in addition to an extensive lava field. Five volcanoes exhibited detectable thermal, and presumed fumarolic, activity (Deception, Zavodovski, Candlemas, Bristol, and Bellingshausen islands). A minor eruption reported at Marion Island was not detected in our survey due to its small size. This study also discovered a new active vent on Mount Michael, tracked dramatic vent enlargement on Heard Island, and provides an improved picture of the morphology of some of the volcanoes.

  2. Integrated Time and Phase Synchronization Strategy for a Multichannel Spaceborne-Stationary Bistatic SAR System

    Directory of Open Access Journals (Sweden)

    Feng Hong

    2016-07-01

    Full Text Available The spatial separation of the transmitter and receiver in Bistatic Synthetic Aperture Radar (BiSAR makes it a promising and useful supplement to a classical Monostatic SAR system (MonoSAR. This paper proposes a novel integrated time and phase synchronization strategy for a multichannel spaceborne-stationary BiSAR system. Firstly, the time synchronization strategy is proposed, which includes Pulse Repetition Frequency (PRF generation under noisy conditions, multichannel calibration and the alignment of the recorded data with the orbital data. Furthermore, the phase synchronization strategy, which fully considers the deteriorative factors in the BiSAR configuration, is well studied. The contribution of the phase synchronization strategy includes two aspects: it not only compensates the phase error, but also improves the Signal to Noise Ratio (SNR of the obtained signals. Specifically, all direct signals on different PRF time can be reconstructed with the shift and phase compensation operation using a reference signal. Besides, since the parameters of the reference signal can be estimated only once using the selected practical direct signal and a priori information, the processing complexity is well reduced. Final imaging results with and without compensation for real data are presented to validate the proposed synchronization strategy.

  3. Airborne and spaceborne radar images for geologic and environmental mapping in the Amazon rain forest, Brazil

    Science.gov (United States)

    Ford, John P.; Hurtak, James J.

    1986-01-01

    Spaceborne and airborne radar image of portions of the Middle and Upper Amazon basin in the state of Amazonas and the Territory of Roraima are compared for purposes of geological and environmental mapping. The contrasted illumination geometries and imaging parameters are related to terrain slope and surface roughness characteristics for corresponding areas that were covered by each of the radar imaging systems. Landforms range from deeply dissected mountain and plateau with relief up to 500 m in Roraima, revealing ancient layered rocks through folded residual mountains to deeply beveled pediplain in Amazonas. Geomorphic features provide distinct textural signatures that are characteristic of different rock associations. The principle drainages in the areas covered are the Rio Negro, Rio Branco, and the Rio Japura. Shadowing effects and low radar sensitivity to subtle linear fractures that are aligned parallel or nearly parallel to the direction of radar illumination illustrate the need to obtain multiple coverage with viewing directions about 90 degrees. Perception of standing water and alluvial forest in floodplains varies with incident angle and with season. Multitemporal data sets acquired over periods of years provide an ideal method of monitoring environmental changes.

  4. Mapping Palaeohydrography in Deserts: Contribution from Space-Borne Imaging Radar

    Directory of Open Access Journals (Sweden)

    Philippe Paillou

    2017-03-01

    Full Text Available Space-borne Synthetic Aperture Radar (SAR has the capability to image subsurface features down to several meters in arid regions. A first demonstration of this capability was performed in the Egyptian desert during the early eighties, thanks to the first Shuttle Imaging Radar mission. Global coverage provided by recent SARs, such as the Japanese ALOS/PALSAR sensor, allowed the mapping of vast ancient hydrographic systems in Northern Africa. We present a summary of palaeohydrography results obtained using PALSAR data over large deserts such as the Sahara and the Gobi. An ancient river system was discovered in eastern Lybia, connecting in the past the Kufrah oasis to the Mediterranean Sea, and the terminal part of the Tamanrasett river was mapped in western Mauritania, ending with a large submarine canyon. In southern Mongolia, PALSAR images combined with topography analysis allowed the mapping of the ancient Ulaan Nuur lake. We finally show the potentials of future low frequency SAR sensors by comparing L-band (1.25 GHz and P-band (435 MHz airborne SAR acquisitions over a desert site in southern Tunisia.

  5. A numerical and experimental investigation of the thermal control performance of a spaceborne compressor assembly

    Science.gov (United States)

    Oh, Hyun-Ung; Lee, Min-Kyu; Shin, Somin; Hong, Joo-Sung

    2011-09-01

    Spaceborne pulse tube type cryocoolers are widely used for providing cryogenic temperatures for sensitive infrared, gamma-ray and X-ray detectors. Thermal control for the compressor of the cryocooler is one of the important technologies for the cooling performance, mission life time, and jitter stability of the cooler. The thermal design of the compressor assembly proposed in this study is basically composed of a heat pipe, a radiator, and a heater. In the present work, a method for heat pipe implementation is proposed and investigated to ensure the jitter stability of the compressor under the condition that one heat pipe is not working. An optimal design of the radiator that uses ribs for effective use by minimizing the temperature gradient on the radiator and reducing its weight is introduced. The effectiveness of the thermal design of the compressor assembly is demonstrated by on-orbit thermal analysis using the correlated thermal model obtained from the thermal balance test that is performed under a space simulating environment.

  6. Improving the Monitoring of Crop Productivity Using Spaceborne Solar-Induced Fluorescence

    Science.gov (United States)

    Guan, Kaiyu; Berry, Joseph A.; Zhang, Yongguang; Joiner, Joanna; Guanter, Luis; Badgley, Grayson; Lobell, David B.

    2015-01-01

    Large-scale monitoring of crop growth and yield has important value for forecasting food production and prices and ensuring regional food security. A newly emerging satellite retrieval, solar-induced fluorescence (SIF) of chlorophyll, provides for the first time a direct measurement related to plant photosynthetic activity (i.e. electron transport rate). Here, we provide a framework to link SIF retrievals and crop yield, accounting for stoichiometry, photosynthetic pathways, and respiration losses. We apply this framework to estimate United States crop productivity for 2007-2012, where we use the spaceborne SIF retrievals from the Global Ozone Monitoring Experiment-2 satellite, benchmarked with county-level crop yield statistics, and compare it with various traditional crop monitoring approaches. We find that a SIF-based approach accounting for photosynthetic pathways (i.e. C3 and C4 crops) provides the best measure of crop productivity among these approaches, despite the fact that SIF sensors are not yet optimized for terrestrial applications. We further show that SIF provides the ability to infer the impacts of environmental stresses on autotrophic respiration and carbon-use-efficiency, with a substantial sensitivity of both to high temperatures. These results indicate new opportunities for improved mechanistic understanding of crop yield responses to climate variability and change.

  7. Development of micro-mirror slicer integral field unit for space-borne solar spectrographs

    Science.gov (United States)

    Suematsu, Yoshinori; Saito, Kosuke; Koyama, Masatsugu; Enokida, Yukiya; Okura, Yukinobu; Nakayasu, Tomoyasu; Sukegawa, Takashi

    2017-12-01

    We present an innovative optical design for image slicer integral field unit (IFU) and a manufacturing method that overcomes optical limitations of metallic mirrors. Our IFU consists of a micro-mirror slicer of 45 arrayed, highly narrow, flat metallic mirrors and a pseudo-pupil-mirror array of off-axis conic aspheres forming three pseudo slits of re-arranged slicer images. A prototype IFU demonstrates that the final optical quality is sufficiently high for a visible light spectrograph. Each slicer micro-mirror is 1.58 mm long and 30 μm wide with surface roughness ≤1 nm rms, and edge sharpness ≤ 0.1 μm, etc. This IFU is small size and can be implemented in a multi-slit spectrograph without any moving mechanism and fore optics, in which one slit is real and the others are pseudo slits from the IFU. The IFU mirrors were deposited by a space-qualified, protected silver coating for high reflectivity in visible and near IR wavelength regions. These properties are well suitable for space-borne spectrograph such as the future Japanese solar space mission SOLAR-C. We present the optical design, performance of prototype IFU, and space qualification tests of the silver coating.

  8. Detecting ship targets in spaceborne infrared image based on modeling radiation anomalies

    Science.gov (United States)

    Wang, Haibo; Zou, Zhengxia; Shi, Zhenwei; Li, Bo

    2017-09-01

    Using infrared imaging sensors to detect ship target in the ocean environment has many advantages compared to other sensor modalities, such as better thermal sensitivity and all-weather detection capability. We propose a new ship detection method by modeling radiation anomalies for spaceborne infrared image. The proposed method can be decomposed into two stages, where in the first stage, a test infrared image is densely divided into a set of image patches and the radiation anomaly of each patch is estimated by a Gaussian Mixture Model (GMM), and thereby target candidates are obtained from anomaly image patches. In the second stage, target candidates are further checked by a more discriminative criterion to obtain the final detection result. The main innovation of the proposed method is inspired by the biological mechanism that human eyes are sensitive to the unusual and anomalous patches among complex background. The experimental result on short wavelength infrared band (1.560 - 2.300 μm) and long wavelength infrared band (10.30 - 12.50 μm) of Landsat-8 satellite shows the proposed method achieves a desired ship detection accuracy with higher recall than other classical ship detection methods.

  9. Retrievals of Aerosol Microphysics from Simulations of Spaceborne Multiwavelength Lidar Measurements

    Science.gov (United States)

    Whiteman, David N.; Perez-Ramírez, Daniel; Veselovskii, Igor; Colarco, Peter; Buchard, Virginie

    2017-01-01

    In support of the Aerosol, Clouds, Ecosystems mission, simulations of a spaceborne multiwavelength lidar are performed based on global model simulations of the atmosphere along a satellite orbit track. The yield for aerosol microphysical inversions is quantified and comparisons are made between the aerosol microphysics inherent in the global model and those inverted from both the model's optical data and the simulated three backscatter and two extinction lidar measurements, which are based on the model's optical data. We find that yield can be significantly increased if inversions based on a reduced optical dataset of three backscatter and one extinction are acceptable. In general, retrieval performance is better for cases where the aerosol fine mode dominates although a lack of sensitivity to particles with sizes less than 0.1 microns is found. Lack of sensitivity to coarse mode cases is also found, in agreement with earlier studies. Surface area is generally the most robustly retrieved quantity. The work here points toward the need for ancillary data to aid in the constraints of the lidar inversions and also for joint inversions involving lidar and polarimeter measurements.

  10. Key issues in the thermal design of spaceborne cryogenic infrared instruments

    Science.gov (United States)

    Schember, Helene R.; Rapp, Donald

    1992-12-01

    Thermal design and analysis play an integral role in the development of spaceborne cryogenic infrared (IR) instruments. From conceptual sketches to final testing, both direct and derived thermal requirements place significant constraints on the instrument design. Although in practice these thermal requirements are interdependent, the sources of most thermal constraints may be grouped into six distinct categories. These are: (1) Detector temperatures, (2) Optics temperatures, (3) Pointing or alignment stability, (4) Mission lifetime, (5) Orbit, and (6) Test and Integration. In this paper, we discuss these six sources of thermal requirements with particular regard to development of instrument packages for low background infrared astronomical observatories. In the end, the thermal performance of these instruments must meet a set of thermal requirements. The development of these requirements is typically an ongoing and interactive process, however, and the thermal design must maintain flexibility and robustness throughout the process. The thermal (or cryogenic) engineer must understand the constraints imposed by the science requirements, the specific hardware, the observing environment, the mission design, and the testing program. By balancing these often competing factors, the system-oriented thermal engineer can work together with the experiment team to produce an effective overall design of the instrument.

  11. Highly-efficient, frequency-tripled Nd:YAG laser for spaceborne LIDARs

    Science.gov (United States)

    Treichel, R.; Hoffmann, H.-D.; Luttmann, J.; Morasch, V.; Nicklaus, K.; Wührer, C.

    2017-11-01

    For a spaceborne lidar a highly reliable, long living and efficient laser source is absolutely essential. Within the frame of the development of a laser source for the backscatter lidar ATLID, which will be flown on EarthCare mission, we setup and tested a predevelopment model of an injection-seeded, diode pumped, frequency tripled, pulsed high power Nd:YAG MOPA laser operating nominally at 100 Hz pulse repetition frequency. We also tested the burst operation mode. The excellent measured performance parameter will be introduced. The oscillator rod is longitudinally pumped from both sides. The oscillator has been operated with three cavity control methods: "Cavity Dither", "Pound-Drever-Hall" and "Adaptive Ramp & Fire". Especially the latter method is very suitable to operate the laser in harsh vibrating environment such in airplanes. The amplifier bases on the InnoSlab design concept. The constant keeping of a moderate fluence in the InnoSlab crystal permits excellent possibilities to scale the pulse energy to several 100 mJ. An innovative pump unit and optics makes the laser performance insensitive to inhomogeneous diode degradation and allows switching of additional redundant diodes. Further key features have been implemented in a FM design concept. The operational lifetime is extended by the implementation of internal redundancies for the most critical parts. The reliability is increased due to the higher margin onto the laser induced damage threshold by a pressurized housing. Additionally air-to-vacuum effects becomes obsolete. A high efficient heat removal concept has been implemented.

  12. Memory design

    DEFF Research Database (Denmark)

    Tanderup, Sisse

    by cultural forms, often specifically by the concept of memory in philosophy, sociology and psychology, while Danish design traditionally has been focusing on form and function with frequent references to the forms of nature. Alessi's motivation for investigating the concept of memory is that it adds......Mind and Matter - Nordik 2009 Conference for Art Historians Design Matters Contributed Memory design BACKGROUND My research concerns the use of memory categories in the designs by the companies Alessi and Georg Jensen. When Alessi's designers create their products, they are usually inspired...... a cultural dimension to the design objects, enabling the objects to make an identity-forming impact. Whether or not the concept of memory plays a significant role in Danish design has not yet been elucidated fully. TERMINOLOGY The concept of "memory design" refers to the idea that design carries...

  13. Disputed Memory

    DEFF Research Database (Denmark)

    , individual and political discourse and electronic social media. Analyzing memory disputes in various local, national and transnational contexts, the chapters demonstrate the political power and social impact of painful and disputed memories. The book brings new insights into current memory disputes...... in Central, Eastern and Southeastern Europe. It contributes to the understanding of processes of memory transmission and negotiation across borders and cultures in Europe, emphasizing the interconnectedness of memory with emotions, mediation and politics....... century in the region. Written by an international group of scholars from a diversity of disciplines, the chapters approach memory disputes in methodologically innovative ways, studying representations and negotiations of disputed pasts in different media, including monuments, museum exhibitions...

  14. Main Memory

    OpenAIRE

    Boncz, Peter; Liu, Lei; Özsu, M.

    2008-01-01

    htmlabstractPrimary storage, presently known as main memory, is the largest memory directly accessible to the CPU in the prevalent Von Neumann model and stores both data and instructions (program code). The CPU continuously reads instructions stored there and executes them. It is also called Random Access Memory (RAM), to indicate that load/store instructions can access data at any location at the same cost, is usually implemented using DRAM chips, which are connected to the CPU and other per...

  15. A Fault-Tolerant Radiation-Robust Mass Storage Concept for Highly Scaled Flash Memory

    Science.gov (United States)

    Fuchs, Cristian M.; Trinitis, Carsten; Appel, Nicolas; Langer, Martin

    2015-09-01

    Future spacemissions will require vast amounts of data to be stored and processed aboard spacecraft. While satisfying operational mission requirements, storage systems must guarantee data integrity and recover damaged data throughout the mission. NAND-flash memories have become popular for space-borne high performance mass memory scenarios, though future storage concepts will rely upon highly scaled flash or other memory technologies. With modern flash memory, single bit erasure coding and RAID based concepts are insufficient. Thus, a fully run-time configurable, high performance, dependable storage concept, requiring a minimal set of logic or software. The solution is based on composite erasure coding and can be adjusted for altered mission duration or changing environmental conditions.

  16. Collaging Memories

    Science.gov (United States)

    Wallach, Michele

    2011-01-01

    Even middle school students can have memories of their childhoods, of an earlier time. The art of Romare Bearden and the writings of Paul Auster can be used to introduce ideas about time and memory to students and inspire works of their own. Bearden is an exceptional role model for young artists, not only because of his astounding art, but also…

  17. Memory Magic.

    Science.gov (United States)

    Hartman, Thomas G.; Nowak, Norman

    This paper outlines several "tricks" that aid students in improving their memories. The distinctions between operational and figural thought processes are noted. Operational memory is described as something that allows adults to make generalizations about numbers and the rules by which they may be combined, thus leading to easier memorization.…

  18. Memory loss

    Science.gov (United States)

    ... barbiturates or ( hypnotics ) ECT (electroconvulsive therapy) (most often short-term memory loss) Epilepsy that is not well controlled Illness that ... appointment. Medical history questions may include: Type of memory loss, such as short-term or long-term Time pattern, such as how ...

  19. Episodic Memories

    Science.gov (United States)

    Conway, Martin A.

    2009-01-01

    An account of episodic memories is developed that focuses on the types of knowledge they represent, their properties, and the functions they might serve. It is proposed that episodic memories consist of "episodic elements," summary records of experience often in the form of visual images, associated to a "conceptual frame" that provides a…

  20. Flavor Memory

    NARCIS (Netherlands)

    Mojet, Jos; Köster, Ep

    2016-01-01

    Odor, taste, texture, temperature, and pain all contribute to the perception and memory of food flavor. Flavor memory is also strongly linked to the situational aspects of previous encounters with the flavor, but does not depend on the precise recollection of its sensory features as in vision and

  1. Main Memory

    NARCIS (Netherlands)

    P.A. Boncz (Peter); L. Liu (Lei); M. Tamer Özsu

    2008-01-01

    htmlabstractPrimary storage, presently known as main memory, is the largest memory directly accessible to the CPU in the prevalent Von Neumann model and stores both data and instructions (program code). The CPU continuously reads instructions stored there and executes them. It is also called Random

  2. Accessing memory

    Science.gov (United States)

    Yoon, Doe Hyun; Muralimanohar, Naveen; Chang, Jichuan; Ranganthan, Parthasarathy

    2017-09-26

    A disclosed example method involves performing simultaneous data accesses on at least first and second independently selectable logical sub-ranks to access first data via a wide internal data bus in a memory device. The memory device includes a translation buffer chip, memory chips in independently selectable logical sub-ranks, a narrow external data bus to connect the translation buffer chip to a memory controller, and the wide internal data bus between the translation buffer chip and the memory chips. A data access is performed on only the first independently selectable logical sub-rank to access second data via the wide internal data bus. The example method also involves locating a first portion of the first data, a second portion of the first data, and the second data on the narrow external data bus during separate data transfers.

  3. Children's Representation and Imitation of Events: How Goal Organization Influences 3-Year-Old Children's Memory for Action Sequences

    Science.gov (United States)

    Loucks, Jeff; Mutschler, Christina; Meltzoff, Andrew N.

    2017-01-01

    Children's imitation of adults plays a prominent role in human cognitive development. However, few studies have investigated how children represent the complex structure of observed actions which underlies their imitation. We integrate theories of action segmentation, memory, and imitation to investigate whether children's event representation is…

  4. Development of compact integral field unit for spaceborne solar spectro-polarimeter

    Science.gov (United States)

    Suematsu, Y.; Koyama, M.; Sukegawa, T.; Enokida, Y.; Saito, K.; Okura, Y.; Nakayasu, T.; Ozaki, S.; Tsuneta, S.

    2017-11-01

    optics is the best option among the three. However, the image slicers are presently limited either by their risk in the case of classical glass polishing techniques (see Vivès et al. [11] for recent development) or by their optical performances when constituted by metallic mirrors. For space instruments, small sized units are much advantageous and demands that width of each slicer mirror is as narrow as an optimal slit width (hard to manufacture with glass polishing techniques. On the other hand, Canon is developing a novel technique for such as high performance gratings which can be applicable for manufacturing high optical performance metallic mirrors of small dimensions. For the space-borne spectrograph of SUVIT to be aboard SOLAR-C, we designed the IFS made of a micro image slicer of 45 arrayed 30-micron-thick metal mirrors and a pseudo-pupil metal mirror array re-formatting three pseudo-slits; the design is feasible for optical configuration sharing a spectrograph with a conventional real slit. According to the optical deign, Canon manufactured a prototype IFU for evaluation, demonstrating high performances of micro image slicer and pupil mirrors; enough small micro roughness for visible light spectrographs, sharp edges for efficient image slices, surface figure for high image quality, etc. In the following, we describe the optical design of IFU feasible for space-borne spectrograph, manufacturing method to attain high optical performance of metal mirrors developed by Canon, and resulted performance of prototype IFU in detail.

  5. AsteroidFinder - the space-borne telescope to search for NEO Asteroids

    Science.gov (United States)

    Hartl, M.; Mosebach, H.; Schubert, J.; Michaelis, H.; Mottola, S.; Kührt, E.; Schindler, K.

    2017-11-01

    This paper presents the mission profile as well as the optical configuration of the space-borne AsteroidFinder telescope. Its main objective is to retrieve asteroids with orbits interior to the earth's orbit. The instrument requires high sensitivity to detect asteroids with a limiting magnitude of equal or larger than 18.5mag (V-Band) and astrometric accuracy of 1arcsec (1σ). This requires a telescope aperture greater than 400cm2, high image stability, detector with high quantum efficiency (peak > 90%) and very low noise, which is only limited by zodiacal background. The telescope will observe the sky between 30° and 60° in solar elongation. The telescope optics is based on a Cook type TMA. An effective 2°×2° field of view (FOV) is achieved by a fast F/3.4 telescope with near diffraction-limited performance. The absence of centre obscuration or spiders in combination with an accessible intermediate field plane and exit pupil allow for efficient stray light mitigation. Design drivers for the telescope are the required point spread function (PSF) values, an extremely efficient stray light suppression (due to the magnitude requirement mentioned above), the detector performance, and the overall optical and mechanical stability for all orientations of the satellite. To accommodate the passive thermal stabilization scheme and the necessary structural stability, the materials selection for the telescope main structure and the mirrors are of vital importance. A focal plane with four EMCCD detectors is envisaged. The EMCCD technology features shorter integration times, which is in favor regarding the pointing performance of the satellite. The launch of the mission is foreseen for the year 2013 with a subsequent mission lifetime of at least 1 year.

  6. Probing early universe cosmology and high energy physics through space-borne interferometers

    International Nuclear Information System (INIS)

    Ungarelli, C.; Vecchio, A.

    2001-01-01

    We discuss the impact of space-borne laser interferometric experiments operating in the low-frequency window (∼ 1 μHz - 1 Hz), with the goal of identifying the fundamental issues that regard the detection of a primordial background of GW predicted by slow-roll inflationary models, corresponding to h 100 2 Ω ∼ 10 -16 - 10 -15 . We analyse the capabilities of the planned single-instrument LISA mission and the sensitivity improvements that could be achieved by cross-correlating the data streams from a pair of detectors of the LISA-class. We show that the two-detectors configuration is extremely powerful, and leads to the detection of a stochastic background as weak as h 100 2 Ω ∼ 10 -14 . However, such instrumental sensitivity cannot be exploited to achieve a comparable performance for the detection of the primordial component of the background, due to the overwhelming power of the stochastic signal produced by short-period solar-mass binary systems of compact objects, that cannot be resolved as individual sources. We estimate that the primordial background can be detected only if its fractional energy density h 100 2 Ω is greater than a few times 10 -12 . The key conclusion of our analysis is that the typical mHz frequency band, regardless of the instrumental noise level, is the wrong observational window to probe slow-roll inflationary models. We discuss possible follow-on missions with optimal sensitivity in the ∼ μHz-regime and/or in the ∼ 0.1Hz-band specifically aimed at gravitational wave cosmology. (author)

  7. The EnMAP Spaceborne Imaging Spectroscopy Mission for Earth Observation

    Directory of Open Access Journals (Sweden)

    Luis Guanter

    2015-07-01

    Full Text Available Imaging spectroscopy, also known as hyperspectral remote sensing, is based on the characterization of Earth surface materials and processes through spectrally-resolved measurements of the light interacting with matter. The potential of imaging spectroscopy for Earth remote sensing has been demonstrated since the 1980s. However, most of the developments and applications in imaging spectroscopy have largely relied on airborne spectrometers, as the amount and quality of space-based imaging spectroscopy data remain relatively low to date. The upcoming Environmental Mapping and Analysis Program (EnMAP German imaging spectroscopy mission is intended to fill this gap. An overview of the main characteristics and current status of the mission is provided in this contribution. The core payload of EnMAP consists of a dual-spectrometer instrument measuring in the optical spectral range between 420 and 2450 nm with a spectral sampling distance varying between 5 and 12 nm and a reference signal-to-noise ratio of 400:1 in the visible and near-infrared and 180:1 in the shortwave-infrared parts of the spectrum. EnMAP images will cover a 30 km-wide area in the across-track direction with a ground sampling distance of 30 m. An across-track tilted observation capability will enable a target revisit time of up to four days at the Equator and better at high latitudes. EnMAP will contribute to the development and exploitation of spaceborne imaging spectroscopy applications by making high-quality data freely available to scientific users worldwide.

  8. Applying spaceborne reflectivity measurements for calculation of the solar ultraviolet radiation at ground level

    Directory of Open Access Journals (Sweden)

    P. N. den Outer

    2012-12-01

    Full Text Available Long-term analysis of cloud effects on ultraviolet (UV radiation on the ground using spaceborne observations requires the use of instruments that have operated consecutively. The longest data record can be built from the reflectivity measurements produced by the instruments Total Ozone Mapping Spectrometers (TOMS flown on Nimbus 7 from 1979 to 1992, TOMS on Earth Probe from 1996 to 2005, and the Ozone Monitoring Instrument (OMI flown on EOS Aura since 2004. The reflectivity data produced by TOMS on Earth Probe is only included until 2002. A comparison is made with cloud effects inferred from ground-based pyranometer measurements at over 83 World Radiation Data Centre stations. Modelled UV irradiances utilizing the standard reflectivity are compared with measurements of UV irradiances at eight European low-elevation stations. The reflectivity data of the two TOMS instruments shows a consistent agreement, and the required corrections are of low percentage, i.e. 2–3%. In contrast, the reflectivity product of OMI requires correction of 7–10%, and a solar angle dependency therein is more pronounced. These corrections were inferred from a comparison with pyranometer data, and tested using the UV measurements. The average reduction of UV radiation due to clouds for all sites together indicates a small trend: a diminishing cloudiness, in line with ground-based UV observations. Uncorrected implementation of the reflectivity data would have indicated the opposite.

    An optimal area was established for reflectivity data for the calculation of daily sums of UV radiation. It measures approximately 1.25° in latitudinal direction for square-shaped areas overhead the ground-based UV stations. Such an area can be traversed within 5 to 7 h at the average wind speeds found for the West European continent.

  9. Time-delay interferometric ranging for space-borne gravitational-wave detectors

    International Nuclear Information System (INIS)

    Tinto, Massimo; Vallisneri, Michele; Armstrong, J.W.

    2005-01-01

    Space-borne interferometric gravitational-wave detectors, sensitive in the low-frequency (mHz) band, will fly in the next decade. In these detectors, the spacecraft-to-spacecraft light-travel times will necessarily be unequal and time varying, and (because of aberration) will have different values on up- and down-links. In such unequal-armlength interferometers, laser-phase noise will be canceled by taking linear combinations of the laser-phase observables measured between pairs of spacecraft, appropriately time shifted by the light propagation times along the corresponding arms. This procedure, known as time-delay interferometry (TDI), requires an accurate knowledge of the light-time delays as functions of time. Here we propose a high-accuracy technique to estimate these time delays, and we study its use in the context of the Laser Interferometer Space Antenna (LISA) mission. We refer to this ranging technique, which relies on the TDI combinations themselves, as time-delay interferometric ranging (TDIR). For every TDI combination, we show that, by minimizing the rms power in that combination (averaged over integration times ∼10 4 s) with respect to the time-delay parameters, we obtain estimates of the time delays accurate enough to cancel laser noise to a level well below the secondary noises. Thus TDIR allows the implementation of TDI without the use of dedicated interspacecraft ranging systems, with a potential simplification of the LISA design. In this paper we define the TDIR procedure formally, and we characterize its expected performance via simulations with the Synthetic LISA software package

  10. Targeted Memory Reactivation during Sleep Adaptively Promotes the Strengthening or Weakening of Overlapping Memories.

    Science.gov (United States)

    Oyarzún, Javiera P; Morís, Joaquín; Luque, David; de Diego-Balaguer, Ruth; Fuentemilla, Lluís

    2017-08-09

    System memory consolidation is conceptualized as an active process whereby newly encoded memory representations are strengthened through selective memory reactivation during sleep. However, our learning experience is highly overlapping in content (i.e., shares common elements), and memories of these events are organized in an intricate network of overlapping associated events. It remains to be explored whether and how selective memory reactivation during sleep has an impact on these overlapping memories acquired during awake time. Here, we test in a group of adult women and men the prediction that selective memory reactivation during sleep entails the reactivation of associated events and that this may lead the brain to adaptively regulate whether these associated memories are strengthened or pruned from memory networks on the basis of their relative associative strength with the shared element. Our findings demonstrate the existence of efficient regulatory neural mechanisms governing how complex memory networks are shaped during sleep as a function of their associative memory strength. SIGNIFICANCE STATEMENT Numerous studies have demonstrated that system memory consolidation is an active, selective, and sleep-dependent process in which only subsets of new memories become stabilized through their reactivation. However, the learning experience is highly overlapping in content and thus events are encoded in an intricate network of related memories. It remains to be explored whether and how memory reactivation has an impact on overlapping memories acquired during awake time. Here, we show that sleep memory reactivation promotes strengthening and weakening of overlapping memories based on their associative memory strength. These results suggest the existence of an efficient regulatory neural mechanism that avoids the formation of cluttered memory representation of multiple events and promotes stabilization of complex memory networks. Copyright © 2017 the authors 0270-6474/17/377748-11$15.00/0.

  11. An expert system environment for the Generic VHSIC Spaceborne Computer (GVSC)

    Science.gov (United States)

    Cockerham, Ann; Labhart, Jay; Rowe, Michael; Skinner, James

    The authors describe a Phase II Phillips Laboratory Small Business Innovative Research (SBIR) program being performed to implement a flexible and general-purpose inference environment for embedded space and avionics applications. This inference environment is being developed in Ada and takes special advantage of the target architecture, the GVSC. The GVSC implements the MIL-STD-1750A ISA and contains enhancements to allow access of up to 8 MBytes of memory. The inference environment makes use of the Merit Enhanced Traversal Engine (METE) algorithm, which employs the latest inference and knowledge representation strategies to optimize both run-time speed and memory utilization.

  12. Memory Reconsolidation.

    Science.gov (United States)

    Haubrich, Josue; Nader, Karim

    2018-01-01

    Scientific advances in the last decades uncovered that memory is not a stable, fixed entity. Apparently stable memories may become transiently labile and susceptible to modifications when retrieved due to the process of reconsolidation. Here, we review the initial evidence and the logic on which reconsolidation theory is based, the wide range of conditions in which it has been reported and recent findings further revealing the fascinating nature of this process. Special focus is given to conceptual issues of when and why reconsolidation happen and its possible outcomes. Last, we discuss the potential clinical implications of memory modifications by reconsolidation.

  13. Olfactory Memory

    Science.gov (United States)

    Eichenbaum, Howard; Robitsek, R. Jonathan

    2009-01-01

    Odor-recognition memory in rodents may provide a valuable model of cognitive aging. In a recent study we used signal detection analyses to distinguish odor recognition based on recollection versus that based on familiarity. Aged rats were selectively impaired in recollection, with relative sparing of familiarity, and the deficits in recollection were correlated with spatial memory impairments. These results complement electro-physiological findings indicating age-associated deficits in the ability of hippocampal neurons to differentiate contextual information, and this information-processing impairment may underlie the common age-associated decline in olfactory and spatial memory. PMID:19686208

  14. Integrated Active Fire Retrievals and Biomass Burning Emissions Using Complementary Near-Coincident Ground, Airborne and Spaceborne Sensor Data

    Science.gov (United States)

    Schroeder, Wilfrid; Ellicott, Evan; Ichoku, Charles; Ellison, Luke; Dickinson, Matthew B.; Ottmar, Roger D.; Clements, Craig; Hall, Dianne; Ambrosia, Vincent; Kremens, Robert

    2013-01-01

    Ground, airborne and spaceborne data were collected for a 450 ha prescribed fire implemented on 18 October 2011 at the Henry W. Coe State Park in California. The integration of various data elements allowed near coincident active fire retrievals to be estimated. The Autonomous Modular Sensor-Wildfire (AMS) airborne multispectral imaging system was used as a bridge between ground and spaceborne data sets providing high quality reference information to support satellite fire retrieval error analyses and fire emissions estimates. We found excellent agreement between peak fire radiant heat flux data (less than 1% error) derived from near-coincident ground radiometers and AMS. Both MODIS and GOES imager active fire products were negatively influenced by the presence of thick smoke, which was misclassified as cloud by their algorithms, leading to the omission of fire pixels beneath the smoke, and resulting in the underestimation of their retrieved fire radiative power (FRP) values for the burn plot, compared to the reference airborne data. Agreement between airborne and spaceborne FRP data improved significantly after correction for omission errors and atmospheric attenuation, resulting in as low as 5 difference between AquaMODIS and AMS. Use of in situ fuel and fire energy estimates in combination with a collection of AMS, MODIS, and GOES FRP retrievals provided a fuel consumption factor of 0.261 kg per MJ, total energy release of 14.5 x 10(exp 6) MJ, and total fuel consumption of 3.8 x 10(exp 6) kg. Fire emissions were calculated using two separate techniques, resulting in as low as 15 difference for various species

  15. An A.P.L. micro-programmed machine: implementation on a Multi-20 mini-computer, memory organization, micro-programming and flowcharts

    International Nuclear Information System (INIS)

    Granger, Jean-Louis

    1975-01-01

    This work deals with the presentation of an APL interpreter implemented on an MULTI 20 mini-computer. It includes a left to right syntax analyser, a recursive routine for generation and execution. This routine uses a beating method for array processing. Moreover, during the execution of all APL statements, dynamic memory allocation is used. Execution of basic operations has been micro-programmed. The basic APL interpreter has a length of 10 K bytes. It uses overlay methods. (author) [fr

  16. Multiferroic Memories

    Directory of Open Access Journals (Sweden)

    Amritendu Roy

    2012-01-01

    Full Text Available Multiferroism implies simultaneous presence of more than one ferroic characteristics such as coexistence of ferroelectric and magnetic ordering. This phenomenon has led to the development of various kinds of materials and conceptions of many novel applications such as development of a memory device utilizing the multifunctionality of the multiferroic materials leading to a multistate memory device with electrical writing and nondestructive magnetic reading operations. Though, interdependence of electrical- and magnetic-order parameters makes it difficult to accomplish the above and thus rendering the device to only two switchable states, recent research has shown that such problems can be circumvented by novel device designs such as formation of tunnel junction or by use of exchange bias. In this paper, we review the operational aspects of multiferroic memories as well as the materials used for these applications along with the designs that hold promise for the future memory devices.

  17. Potential of EnMAP spaceborne imaging spectroscopy for the prediction of common surface soil properties and expected accuracy

    Science.gov (United States)

    Chabrillat, Sabine; Foerster, Saskia; Steinberg, Andreas; Stevens, Antoine; Segl, Karl

    2016-04-01

    algorithms are examined based on the analyses of chemical-physical features from the soil spectral reflectance and/or multivariate established techniques such as Partial-Least Squares PLS, Support-Vector Machine SVM, to determine common surface soil properties, in particular soil organic carbon (SOC), clay and iron oxide content. Results show that EnMAP is able to predict clay, free iron oxide, and SOC with an RV2 between 0.53 and 0.67 compared to airborne imagery with RV2 between 0.64 and 0.74. The correlation between EnMAP and airborne imagery prediction results is high (Pearson coefficients between 0.84 and 0.91). Furthermore, spatial distribution is coherent between the airborne mapping and simulated EnMAP mapping as shown with a spatial structure analysis. In general, this paper demonstrates the high potential of upcoming spaceborne hyperspectral missions for soil science studies but also shows the need for future adapted strategies to fulfill the entire potential of soil spectroscopy for orbital utilization.

  18. Color Memory

    OpenAIRE

    Pate, Monica; Raclariu, Ana-Maria; Strominger, Andrew

    2017-01-01

    A transient color flux across null infinity in classical Yang-Mills theory is considered. It is shown that a pair of test `quarks' initially in a color singlet generically acquire net color as a result of the flux. A nonlinear formula is derived for the relative color rotation of the quarks. For weak color flux the formula linearizes to the Fourier transform of the soft gluon theorem. This color memory effect is the Yang-Mills analog of the gravitational memory effect.

  19. Memory NK cells: why do they reside in the liver?

    OpenAIRE

    Jiang, Xiaojun; Chen, Yonglin; Peng, Hui; Tian, Zhigang

    2013-01-01

    Immune memory is the hallmark of adaptive immunity. However, recent studies have shown that natural killer (NK) cells, key components of the innate immune system, also mediate memory responses in mice and humans. Strikingly, memory NK cells were liver-resident in some models, raising the question as to whether the liver is a special organ for the acquisition of NK cell memory. Here, we review the characteristics of NK cell memory by summarizing recent progress and discuss how the liver may ge...

  20. Command vector memory systems: high performance at low cost

    OpenAIRE

    Corbal San Adrián, Jesús; Espasa Sans, Roger; Valero Cortés, Mateo

    1998-01-01

    The focus of this paper is on designing both a low cost and high performance, high bandwidth vector memory system that takes advantage of modern commodity SDRAM memory chips. To successfully extract the full bandwidth from SDRAM parts, we propose a new memory system organization based on sending commands to the memory system as opposed to sending individual addresses. A command specifies, in a few bytes, a request for multiple independent memory words. A command is similar to a burst found in...

  1. Providing for organizational memory in computer supported meetings

    OpenAIRE

    Schwabe, Gerhard

    1994-01-01

    Meeting memory features are poorly integrated into current group support systems (GSS). In this article, I discuss how to introduce meeting memory functionality into a GSS. The article first introduces the benefits of effective meetings and organizational memory to an organization. Then, the following challenges to design are discussed: How to store semantically rich output, how to build up the meeting memory with a minimum of additional effort, how to integrate meeting memory into organizati...

  2. Improving everyday memory performance after acquired brain injury: An RCT on recollection and working memory training.

    Science.gov (United States)

    Richter, Kim Merle; Mödden, Claudia; Eling, Paul; Hildebrandt, Helmut

    2018-04-26

    To show the effectiveness of a combined recognition and working memory training on everyday memory performance in patients suffering from organic memory disorders. In this double-blind, randomized controlled Study 36 patients with organic memory impairments, mainly attributable to stroke, were assigned to either the experimental or the active control group. In the experimental group a working memory training was combined with a recollection training based on the repetition-lag procedure. Patients in the active control group received the memory therapy usually provided in the rehabilitation center. Both groups received nine hours of therapy. Prior (T0) and subsequent (T1) to the therapy, patients were evaluated on an everyday memory test (EMT) as well as on a neuropsychological test battery. Based on factor analysis of the neuropsychological test scores at T0 we calculated composite scores for working memory, verbal learning and word fluency. After treatment, the intervention group showed a significantly greater improvement for WM performance compared with the active control group. More importantly, performance on the EMT also improved significantly in patients receiving the recollection and working memory training compared with patients with standard memory training. Our results show that combining working memory and recollection training significantly improves performance on everyday memory tasks, demonstrating far transfer effects. The present study argues in favor of a process-based approach for treating memory impairments. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  3. Development of grazing incidence devices for space-borne time of flight mass spectrometry

    Science.gov (United States)

    Cadu, A.; Devoto, P.; Louarn, P.; Sauvaud, J.-A.

    2012-04-01

    Time of flight mass spectrometer is widely used to study space plasmas in planetary and solar missions. This space-borne instrument selects ions in function of their energy through an electrostatic analyzer. Particles are then post-accelerated to energies in the range of 20 keV to cross a carbon foil. At the foil exit, electrons are emitted and separated from ion beam in the time of flight section. A first detector (a Micro-Channel Plate or MCP) emits a start signal at electron arrival and a second one emits a stop signal at incident ion end of path. The time difference gives the speed of the particle and its mass can be calculated, knowing its initial energy. However, current instruments suffer from strong limitations. The post acceleration needs very high voltage power supplies which are heavy, have a high power consumption and imply technical constraints for the development. A typical instrument weighs from 5 to 6 kg, includes a 20 kV power supply, consumes a least 5 W and encounters corona effect and electrical breakdown problems. Moreover, despite the particle high energy range, scattering and straggling phenomena in the carbon foil significantly reduce the instrument overall resolution. Some methods, such as electrostatic focus lenses or reflectrons, really improve mass separation but global system efficiency remains very low because of the charge state dependence of such devices. The main purpose of our work is to replace carbon foil by grazing incidence MCP's - also known as MPO's, for Micro Pore Optics - for electron emission. Thus, incident particles would back-scatter onto the channel inner surface with an angle of a few degrees. With this solution, we can decrease dispersion sources and lower the power supplies to post accelerate ions. The result would be a lighter and simpler instrument with a substantial resolution improvement. We have first simulated MPO's behavior with TRIM and MARLOWE Monte-Carlo codes. Energy scattering and output angle computed

  4. Advancing spaceborne tools for the characterization of planetary ionospheres and circumstellar environments

    Science.gov (United States)

    Douglas, Ewan Streets

    This work explores remote sensing of planetary atmospheres and their circumstellar surroundings. The terrestrial ionosphere is a highly variable space plasma embedded in the thermosphere. Generated by solar radiation and predominantly composed of oxygen ions at high altitudes, the ionosphere is dynamically and chemically coupled to the neutral atmosphere. Variations in ionospheric plasma density impact radio astronomy and communications. Inverting observations of 83.4 nm photons resonantly scattered by singly ionized oxygen holds promise for remotely sensing the ionospheric plasma density. This hypothesis was tested by comparing 83.4 nm limb profiles recorded by the Remote Atmospheric and Ionospheric Detection System aboard the International Space Station to a forward model driven by coincident plasma densities measured independently via ground-based incoherent scatter radar. A comparison study of two separate radar overflights with different limb profile morphologies found agreement between the forward model and measured limb profiles. A new implementation of Chapman parameter retrieval via Markov chain Monte Carlo techniques quantifies the precision of the plasma densities inferred from 83.4 nm emission profiles. This first study demonstrates the utility of 83.4 nm emission for ionospheric remote sensing. Future visible and ultraviolet spectroscopy will characterize the composition of exoplanet atmospheres; therefore, the second study advances technologies for the direct imaging and spectroscopy of exoplanets. Such spectroscopy requires the development of new technologies to separate relatively dim exoplanet light from parent star light. High-contrast observations at short wavelengths require spaceborne telescopes to circumvent atmospheric aberrations. The Planet Imaging Concept Testbed Using a Rocket Experiment (PICTURE) team designed a suborbital sounding rocket payload to demonstrate visible light high-contrast imaging with a visible nulling coronagraph

  5. THE FUTURE SPACEBORNE HYPERSPECTRAL IMAGER ENMAP: ITS IN-FLIGHT RADIOMETRIC AND GEOMETRIC CALIBRATION CONCEPT

    Directory of Open Access Journals (Sweden)

    M. Schneider

    2012-07-01

    Full Text Available The German Aerospace Center DLR – namely the Earth Observation Center EOC and the German Space Operations Center GSOC – is responsible for the establishment of the ground segment of the future German hyperspectral satellite mission EnMAP (Environmental Mapping and Analysis Program. The Earth Observation Center has long lasting experiences with air- and spaceborne acquisition, processing, and analysis of hyperspectral image data. In the first part of this paper, an overview of the radiometric in-flight calibration concept including dark value measurements, deep space measurements, internal lamps measurements and sun measurements is presented. Complemented by pre-launch calibration and characterization these analyses will deliver a detailed and quantitative assessment of possible changes of spectral and radiometric characteristics of the hyperspectral instrument, e.g. due to degradation of single elements. A geometric accuracy of 100 m, which will be improved to 30 m with respect to a used reference image, if it exists, will be achieved by ground processing. Therfore, and for the required co-registration accuracy between SWIR and VNIR channels, additional to the radiometric calibration, also a geometric calibration is necessary. In the second part of this paper, the concept of the geometric calibration is presented in detail. The geometric processing of EnMAP scenes will be based on laboratory calibration results. During repeated passes over selected calibration areas images will be acquired. The update of geometric camera model parameters will be done by an adjustment using ground control points, which will be extracted by automatic image matching. In the adjustment, the improvements of the attitude angles (boresight angles, the improvements of the interior orientation (view vector and the improvements of the position data are estimated. In this paper, the improvement of the boresight angles is presented in detail as an example. The other

  6. The Future Spaceborne Hyperspectral Imager Enmap: its In-Flight Radiometric and Geometric Calibration Concept

    Science.gov (United States)

    Schneider, M.; Müller, R.; Krawzcyk, H.; Bachmann, M.; Storch, T.; Mogulsky, V.; Hofer, S.

    2012-07-01

    The German Aerospace Center DLR - namely the Earth Observation Center EOC and the German Space Operations Center GSOC - is responsible for the establishment of the ground segment of the future German hyperspectral satellite mission EnMAP (Environmental Mapping and Analysis Program). The Earth Observation Center has long lasting experiences with air- and spaceborne acquisition, processing, and analysis of hyperspectral image data. In the first part of this paper, an overview of the radiometric in-flight calibration concept including dark value measurements, deep space measurements, internal lamps measurements and sun measurements is presented. Complemented by pre-launch calibration and characterization these analyses will deliver a detailed and quantitative assessment of possible changes of spectral and radiometric characteristics of the hyperspectral instrument, e.g. due to degradation of single elements. A geometric accuracy of 100 m, which will be improved to 30 m with respect to a used reference image, if it exists, will be achieved by ground processing. Therfore, and for the required co-registration accuracy between SWIR and VNIR channels, additional to the radiometric calibration, also a geometric calibration is necessary. In the second part of this paper, the concept of the geometric calibration is presented in detail. The geometric processing of EnMAP scenes will be based on laboratory calibration results. During repeated passes over selected calibration areas images will be acquired. The update of geometric camera model parameters will be done by an adjustment using ground control points, which will be extracted by automatic image matching. In the adjustment, the improvements of the attitude angles (boresight angles), the improvements of the interior orientation (view vector) and the improvements of the position data are estimated. In this paper, the improvement of the boresight angles is presented in detail as an example. The other values and combinations

  7. Looking Back and Looking Forward: Reprising the Promise and Predicting the Future of Formation Flying and Spaceborne GPS Navigation Systems

    Science.gov (United States)

    Bauer, Frank H.; Dennehy, Neil

    2015-01-01

    A retrospective consideration of two 15-year old Guidance, Navigation and Control (GN&C) technology 'vision' predictions will be the focus of this paper. A look back analysis and critique of these late 1990s technology roadmaps out-lining the future vision, for two then nascent, but rapidly emerging, GN&C technologies will be performed. Specifically, these two GN&C technologies were: 1) multi-spacecraft formation flying and 2) the spaceborne use and exploitation of global positioning system (GPS) signals to enable formation flying. This paper reprises the promise of formation flying and spaceborne GPS as depicted in the cited 1999 and 1998 papers. It will discuss what happened to cause that promise to be mostly unfulfilled and the reasons why the envisioned formation flying dream has yet to become a reality. The recent technology trends over the past few years will then be identified and a renewed government interest in spacecraft formation flying/cluster flight will be highlighted. The authors will conclude with a reality-tempered perspective, 15 years after the initial technology roadmaps were published, predicting a promising future of spacecraft formation flying technology development over the next decade.

  8. Potential of Space-Borne Hyperspectral Data for Biomass Quantification in an Arid Environment: Advantages and Limitations

    Directory of Open Access Journals (Sweden)

    Harald Zandler

    2015-04-01

    Full Text Available In spite of considerable efforts to monitor global vegetation, biomass quantification in drylands is still a major challenge due to low spectral resolution and considerable background effects. Hence, this study examines the potential of the space-borne hyperspectral Hyperion sensor compared to the multispectral Landsat OLI sensor in predicting dwarf shrub biomass in an arid region characterized by challenging conditions for satellite-based analysis: The Eastern Pamirs of Tajikistan. We calculated vegetation indices for all available wavelengths of both sensors, correlated these indices with field-mapped biomass while considering the multiple comparison problem, and assessed the predictive performance of single-variable linear models constructed with data from each of the sensors. Results showed an increased performance of the hyperspectral sensor and the particular suitability of indices capturing the short-wave infrared spectral region in dwarf shrub biomass prediction. Performance was considerably poorer in the area with less vegetation cover. Furthermore, spatial transferability of vegetation indices was not feasible in this region, underlining the importance of repeated model building. This study indicates that upcoming space-borne hyperspectral sensors increase the performance of biomass prediction in the world’s arid environments.

  9. Optical timing receiver for the NASA Spaceborne Ranging System. Part II: high precision event-timing digitizer

    Energy Technology Data Exchange (ETDEWEB)

    Leskovar, Branko; Turko, Bojan

    1978-08-01

    Position-resolution capabilities of the NASA Spaceborne Laser Ranging System are essentially determined by the timeresolution capabilities of its optical timing receiver. The optical timing receiver consists of a fast photoelectric device; (e.g., photomultiplier or an avalanche photodiode detector), a timing discriminator, a high-precision event-timing digitizer, and a signal-processing system. The time-resolution capabilities of the receiver are determined by the photoelectron time spread of the photoelectric device, the time walk and resolution characteristics of the timing discriminator, and the resolution of the event-timing digitizer. It is thus necessary to evaluate available fast photoelectronic devices with respect to the time-resolution capabilities, and to develop a very low time walk timing discriminator and a high-resolution event-timing digitizer to be used in the high-resolution spaceborne laser ranging system receiver. This part of the report describes the development of a high precision event-timing digitizer. The event-timing digitizer is basically a combination of a very accurate high resolution real time digital clock and an interval timer. The timing digitizer is a high resolution multiple stop clock, counting the time up to 131 days in 19.5 ps increments.

  10. Report on International Spaceborne Imaging Spectroscopy Technical Committee Calibration and Validation Workshop, National Environment Research Council Field Spectroscopy Facility, University of Edinburgh

    Science.gov (United States)

    Ong, C,; Mueller, A.; Thome, K.; Bachmann, M.; Czapla-Myers, J.; Holzwarth, S.; Khalsa, S. J.; Maclellan, C.; Malthus, T.; Nightingale, J.; hide

    2016-01-01

    Calibration and validation are fundamental for obtaining quantitative information from Earth Observation (EO) sensor data. Recognising this and the impending launch of at least five sensors in the next five years, the International Spaceborne Imaging Spectroscopy Technical Committee instigated a calibration and validation initiative. A workshop was conducted recently as part of this initiative with the objective of establishing a good practice framework for radiometric and spectral calibration and validation in support of spaceborne imaging spectroscopy missions. This paper presents the outcomes and recommendations for future work arising from the workshop.

  11. a Study of Co-Planing Technology of Spaceborne, Airborne and Ground Remote Sensing Detecting Resource, Driven by Disaster Emergency Task

    Science.gov (United States)

    Yu, F.; Chen, H.; Tu, K.; Wen, Q.; He, J.; Gu, X.; Wang, Z.

    2018-04-01

    Facing the monitoring needs of emergency responses to major disasters, combining the disaster information acquired at the first time after the disaster and the dynamic simulation result of the disaster chain evolution process, the overall plan for coordinated planning of spaceborne, airborne and ground observation resources have been designed. Based on the analysis of the characteristics of major disaster observation tasks, the key technologies of spaceborne, airborne and ground collaborative observation project are studied. For different disaster response levels, the corresponding workflow tasks are designed. On the basis of satisfying different types of disaster monitoring demands, the existing multi-satellite collaborative observation planning algorithms are compared, analyzed, and optimized.

  12. Classic and contemporary perspectives on memory

    Directory of Open Access Journals (Sweden)

    Bentosela, Mariana

    2009-06-01

    Full Text Available Humans organize past events as “memories”, i.e. what we learn is encoded and stored in the brain, and by accumulating relevant environmental information we better cope with similar situations in the future. The main research on memory began in the 70s and the most important conclusions have been derived, on the one hand, from animal experiments, and on the other hand, from clinical studies of amnesic patients. Many classification systems of memory have been proposed. First, authors have distinguished among the different phases involved in the process of memory formation: short-term and long-term memory. Second, declarative and non-declarative memories have been recognized. Last, researchers have conceived the need to evaluate memory in a systematic manner through behavioral as well as pharmacological means, in different moments or times to be able to have independent access to the study of the different memory phases or types of memory. This approach to the study of memory has allowed evaluating drug effects on memory and also understanding the molecular mechanisms involved in memory processes. In addition, this research has also aimed at studying brain regions implicated in the diverse memory phenomena under investigation.

  13. An intrinsic poperty of memory of the Cellular automaton infrastructure of Nature leading to the organization of the physical world as an Internet o things; TOE = IOT

    Science.gov (United States)

    Berkovich, Simon

    2015-04-01

    The undamental advantage of a Cellular automaton construction foris that it can be viewed as an undetectable absolute frame o reference, in accordance with Lorentz-Poincare's interpretation.. The cellular automaton model for physical poblems comes upon two basic hurdles: (1) How to find the Elemental Rule that, and how to get non-locality from local transformations. Both problems are resolved considering the transfomation rule of mutual distributed synchronization Actually any information proessing device starts with a clocking system. and it turns out that ``All physical phenomena are different aspects of the high-level description of distributed mutual synchronization in a network of digital clocks''. Non-locality comes from two hugely different time-scales of signaling.. The universe is acombinines information and matter processes, These fast spreading diffusion wave solutions create the mechanism of the Holographic Universe. And thirdly Disengaged from synchronization, circular counters can perform memory functions by retaining phases of their oscillations, an idea of Von Neumann'. Thus, the suggested model generates the necessary constructs for the physical world as an Internet of Things. Life emerges due to the specifics of macromolecules that serve as communication means, with the holographic memory...

  14. The Cognitive Neuroscience of Human Memory Since H.M

    Science.gov (United States)

    Squire, Larry R.; Wixted, John T.

    2011-01-01

    Work with patient H.M., beginning in the 1950s, established key principles about the organization of memory that inspired decades of experimental work. Since H.M., the study of human memory and its disorders has continued to yield new insights and to improve understanding of the structure and organization of memory. Here we review this work with emphasis on the neuroanatomy of medial temporal lobe and diencephalic structures important for memory, multiple memory systems, visual perception, immediate memory, memory consolidation, the locus of long-term memory storage, the concepts of recollection and familiarity, and the question of how different medial temporal lobe structures may contribute differently to memory functions. PMID:21456960

  15. Probing electron density across Ar{sup +} irradiation-induced self-organized TiO{sub 2−x} nanochannels for memory application

    Energy Technology Data Exchange (ETDEWEB)

    Barman, A.; Saini, C. P.; Ghosh, S. K.; Dhar, S.; Kanjilal, A., E-mail: aloke.kanjilal@snu.edu.in [Department of Physics, School of Natural Sciences, Shiv Nadar University, NH-91, Tehsil Dadri, Gautam Buddha Nagar, Uttar Pradesh 201314 (India); Sarkar, P. K.; Roy, A. [Department of Physics, National Institute of Technology, Silchar, Assam 788010 (India); Satpati, B. [Surface Physics and Material Science Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India); Kanjilal, D. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India)

    2016-06-13

    The variation of electron density in TiO{sub 2−x} nanochannels, exhibiting resistive switching phenomenon, produced by Ar{sup +} ion-irradiation at the threshold fluence of 5 × 10{sup 16} ions/cm{sup 2} is demonstrated by X-ray reflectivity (XRR). The transmission electron microscopy reveals the formation of nanochannels, while the energy dispersive X-ray spectroscopy confirms Ti enrichment near the surface due to ion-irradiation, in consistent with the increase in electron density by XRR measurements. Such a variation in Ti concentration indicates the evolution of oxygen vacancies (OVs) along the TiO{sub 2−x} nanochannels, and thus paves the way to explain the operation and performance of the Pt/TiO{sub 2−x}/Pt-based memory devices via OV migration.

  16. Holographic memories

    DEFF Research Database (Denmark)

    Ramanujam, P.S.; Berg, R.H.; Hvilsted, Søren

    1999-01-01

    A Two-dimensional holographic memory for archival storage is described. Assuming a coherent transfer function, an A4 page can be stored at high resolution in an area of 1 mm(2). Recently developed side-chain liquid crystalline azobenzene polyesters are found to be suitable media for holographic...

  17. Sharing Memories

    DEFF Research Database (Denmark)

    Rodil, Kasper; Nielsen, Emil Byskov; Nielsen, Jonathan Bernstorff

    2018-01-01

    in which it was to be contextualized and through a close partnership between aphasics and their caretakers. The underlying design methodology for the MemoryBook is Participatory Design manifested through the collaboration and creations by two aphasic residents and one member of the support staff. The idea...

  18. Memory consolidation

    NARCIS (Netherlands)

    Takashima, A.; Bakker, I.; Schmid, H.-J.

    2016-01-01

    In order to make use of novel experiences and knowledge to guide our future behavior, we must keep large amounts of information accessible for retrieval. The memory system that stores this information needs to be flexible in order to rapidly incorporate incoming information, but also requires that

  19. Skilled Memory.

    Science.gov (United States)

    1980-11-06

    Woodworth, R. S. Experimental Psychology. New York: Henry Holt and Co., 1938. Yates, F. A. The art of memory. London: Rutledge and Kegan Paul, 1966. 50...Group 1 Psychologist (TAEG) ON! Branch Office Dept. of the Navy 1030 East Green Street Orlando, FL 32813 Pasadena, CA 91101 1 Dr. Richard Sorensen I

  20. Intercomparison of spaceborne precipitation radars and its applications in examining precipitation-topography relationships in the Tibetan Plateau

    Science.gov (United States)

    Tang, G.; Gao, J.; Long, D.

    2017-12-01

    Precipitation is one of the most important components in the water and energy cycles. Spaceborne radars are considered the most direct technology for observing precipitation from space since 1998. This study compares and evaluates the only three existing spaceborne precipitation radars, i.e., the Ku-band precipitation radar (TRMM PR), the W-band Cloud Profiling Radar (CloudSat CPR), and the Ku/Ka-band Dual-frequency Precipitation Radar (GPM DPR). In addition, TRMM PR and GPM DPR are evaluated against hourly rain gauge data in Mainland China. The Tibetan Plateau (TP) is known as the Earth's third pole where precipitation is affected profoundly by topography. However, ground gauges are extremely sparse in the TP, and spaceborne radars can provide valuable data with relatively high accuracy. The relationships between precipitation and topography over the TP are investigated using 17-year TRMM PR data and 2-year GPM DPR data, in combination with rain gauge data. Results indicate that: (1) DPR and PR agree with each other and correlate very well with gauges in Mainland China. DPR improves light precipitation detectability significantly compared with PR. However, DPR high sensitivity scans (HS) deviates from DPR normal and matched scans (NS and MS) and PR in the comparison based on global coincident events and rain gauges in China; (2) CPR outperforms the other two radars in terms of light precipitation detection. In terms of global snowfall estimation, DPR and CPR show very different global snowfall distributions originating from different frequencies, retrieval algorithms, and sampling characteristics; and (3) Precipitation generally decreases exponentially with increasing elevation in the TP. The precipitation-topography relationships are regressed using exponential fitting in seventeen river basins in the TP with good coefficients of determination. Due to the short time span of GPM DPR, the relationships based on GPM DPR data are less robust than those derived from

  1. Memory processing in and out of sleep

    NARCIS (Netherlands)

    Cox, R.

    2014-01-01

    Memories established during learning are re-expressed during sleep. Specific memory circuits can be tagged during learning, and these networks may be reactivated during subsequent sleep using those tags. A complex system of rhythmic brain waves, highly coordinated both in space and time, organizes

  2. Intercomparison of Vertical Structure of Storms Revealed by Ground-Based (NMQ and Spaceborne Radars (CloudSat-CPR and TRMM-PR

    Directory of Open Access Journals (Sweden)

    Veronica M. Fall

    2013-01-01

    Full Text Available Spaceborne radars provide great opportunities to investigate the vertical structure of clouds and precipitation. Two typical spaceborne radars for such a study are the W-band Cloud Profiling Radar (CPR and Ku-band Precipitation Radar (PR, which are onboard NASA’s CloudSat and TRMM satellites, respectively. Compared to S-band ground-based radars, they have distinct scattering characteristics for different hydrometeors in clouds and precipitation. The combination of spaceborne and ground-based radar observations can help in the identification of hydrometeors and improve the radar-based quantitative precipitation estimation (QPE. This study analyzes the vertical structure of the 18 January, 2009 storm using data from the CloudSat CPR, TRMM PR, and a NEXRAD-based National Mosaic and Multisensor QPE (NMQ system. Microphysics above, within, and below the melting layer are studied through an intercomparison of multifrequency measurements. Hydrometeors’ type and their radar scattering characteristics are analyzed. Additionally, the study of the vertical profile of reflectivity (VPR reveals the brightband properties in the cold-season precipitation and its effect on the radar-based QPE. In all, the joint analysis of spaceborne and ground-based radar data increases the understanding of the vertical structure of storm systems and provides a good insight into the microphysical modeling for weather forecasts.

  3. Retrieval of Methane Source Strengths in Europe Using a Simple Modeling Approach to Assess the Potential of Spaceborne Lidar Observations

    Science.gov (United States)

    Weaver, C.; Kiemle, C.; Kawa, S. R.; Aalto, T.; Necki, J.; Steinbacher, M.; Arduini, J.; Apadula, F.; Berkhout, H.; Hatakka, J.

    2014-01-01

    We investigate the sensitivity of future spaceborne lidar measurements to changes in surface methane emissions. We use surface methane observations from nine European ground stations and a Lagrangian transport model to infer surface methane emissions for 2010. Our inversion shows the strongest emissions from the Netherlands, the coal mines in Upper Silesia, Poland, and wetlands in southern Finland. The simulated methane surface concentrations capture at least half of the daily variability in the observations, suggesting that the transport model is correctly simulating the regional transport pathways over Europe. With this tool we can test whether proposed methane lidar instruments will be sensitive to changes in surface emissions. We show that future lidar instruments should be able to detect a 50% reduction in methane emissions from the Netherlands and Germany, at least during summer.

  4. Azimuth-Variant Signal Processing in High-Altitude Platform Passive SAR with Spaceborne/Airborne Transmitter

    Directory of Open Access Journals (Sweden)

    Huaizong Shao

    2013-03-01

    Full Text Available High-altitude platforms (HAP or near-space vehicle offers several advantages over current low earth orbit (LEO satellite and airplane, because HAP is not constrained by orbital mechanics and fuel consumption. These advantages provide potential for some specific remote sensing applications that require persistent monitoring or fast-revisiting frequency. This paper investigates the azimuth-variant signal processing in HAP-borne bistatic synthetic aperture radar (BiSAR with spaceborne or airborne transmitter for high-resolution remote sensing. The system configuration, azimuth-variant Doppler characteristics and two-dimensional echo spectrum are analyzed. Conceptual system simulation results are also provided. Since the azimuth-variant BiSAR geometry brings a challenge for developing high precision data processing algorithms, we propose an image formation algorithm using equivalent velocity and nonlinear chirp scaling (NCS to address the azimuth-variant signal processing problem. The proposed algorithm is verified by numerical simulation results.

  5. Space-borne remote sensing of CO2 by IPDA lidar with heterodyne detection: random error estimation

    Science.gov (United States)

    Matvienko, G. G.; Sukhanov, A. Y.

    2015-11-01

    Possibilities of measuring the CO2 column concentration by spaceborne integrated path differential lidar (IPDA) signals in the near IR absorption bands are investigated. It is shown that coherent detection principles applied in the nearinfrared spectral region promise a high sensitivity for the measurement of the integrated dry air column mixing ratio of the CO2. The simulations indicate that for CO2 the target observational requirements (0.2%) for the relative random error can be met with telescope aperture 0.5 m, detector bandwidth 10 MHz, laser energy per impulse 0.3 mJ and averaging 7500 impulses. It should also be noted that heterodyne technique allows to significantly reduce laser power and receiver overall dimensions compared to direct detection.

  6. Precise Orbit Solution for Swarm Using Space-Borne GPS Data and Optimized Pseudo-Stochastic Pulses

    Directory of Open Access Journals (Sweden)

    Bingbing Zhang

    2017-03-01

    Full Text Available Swarm is a European Space Agency (ESA project that was launched on 22 November 2013, which consists of three Swarm satellites. Swarm precise orbits are essential to the success of the above project. This study investigates how well Swarm zero-differenced (ZD reduced-dynamic orbit solutions can be determined using space-borne GPS data and optimized pseudo-stochastic pulses under high ionospheric activity. We choose Swarm space-borne GPS data from 1–25 October 2014, and Swarm reduced-dynamic orbits are obtained. Orbit quality is assessed by GPS phase observation residuals and compared with Precise Science Orbits (PSOs released by ESA. Results show that pseudo-stochastic pulses with a time interval of 6 min and a priori standard deviation (STD of 10−2 mm/s in radial (R, along-track (T and cross-track (N directions are optimized to Swarm ZD reduced-dynamic precise orbit determination (POD. During high ionospheric activity, the mean Root Mean Square (RMS of Swarm GPS phase residuals is at 9–11 mm, Swarm orbit solutions are also compared with Swarm PSOs released by ESA and the accuracy of Swarm orbits can reach 2–4 cm in R, T and N directions. Independent Satellite Laser Ranging (SLR validation indicates that Swarm reduced-dynamic orbits have an accuracy of 2–4 cm. Swarm-B orbit quality is better than those of Swarm-A and Swarm-C. The Swarm orbits can be applied to the geomagnetic, geoelectric and gravity field recovery.

  7. Optical timing receiver for the NASA Spaceborne Ranging System. Part I. Dual peak-sensing timing discriminator

    International Nuclear Information System (INIS)

    Leskovar, B.; Lo, C.C.; Zizka, G.

    1978-01-01

    Position-resolution capabilities of the NASA Spaceborne Laser Ranging System are essentially determined by the time-resolution capabilities of its optical timing receiver. The optical timing receiver consists of a fast photoelectric device; (e.g., photomultiplier or an avalanche photodiode detector), a timing discriminator, a high-precision event-timing digitizer, and a signal-processing system. The time-resolution capabilities of the receiver are determined by the photoelectron time spread of the photoelectric device, the time walk and resolution characteristics of the timing discriminator, and the resolution of the event-timing digitizer. It is thus necessary to evaluate available fast photoelectronic devices with respect to their time-resolution capabilities, to design a very low time walk timing discriminator and to develop a high-resolution event-timing digitizer which will be used in the high-resolution spaceborne laser ranging system receiver. The development of a new dual-peak sensing timing discriminator is described. The amplitude dependent time walk is less than +-150 psec for a 100:1 dynamic range of Gaussian-shaped input signals having pulse widths between 11 and 17 nsec. The unit produces 800 mV negative output pulses, each 10 nsec wide, and 3V positive pulses with widths of 15 nsec. The time delay through the discriminator is approximately 37 nsec. In this discriminator the input signal is processed by a peak-crossing circuit which produces a bipolar pulse having its zero-crossing point at the peak of the input signal. All essential functions in the discriminator are performed by means of tunnel diodes with backward diodes as nonlinear loads. The discriminator is designed to be CAMAC compatible to a conventional time-interval unit or a high-precision event timing digitizer. The adjustment procedure for obtaining minimum time walk is also given

  8. The effect of spatial organization of targets and distractors on the capacity to selectively memorize objects in visual short-term memory.

    Science.gov (United States)

    Abbes, Aymen Ben; Gavault, Emmanuelle; Ripoll, Thierry

    2014-01-01

    We conducted a series of experiments to explore how the spatial configuration of objects influences the selection and the processing of these objects in a visual short-term memory task. We designed a new experiment in which participants had to memorize 4 targets presented among 4 distractors. Targets were cued during the presentation of distractor objects. Their locations varied according to 4 spatial configurations. From the first to the last configuration, the distance between targets' locations was progressively increased. The results revealed a high capacity to select and memorize targets embedded among distractors even when targets were extremely distant from each other. This capacity is discussed in relation to the unitary conception of attention, models of split attention, and the competitive interaction model. Finally, we propose that the spatial dispersion of objects has different effects on attentional allocation and processing stages. Thus, when targets are extremely distant from each other, attentional allocation becomes more difficult while processing becomes easier. This finding implicates that these 2 aspects of attention need to be more clearly distinguished in future research.

  9. Exponential increase in the on-off ratio of conductance in organic memory devices by controlling the surface morphology of the devices

    Science.gov (United States)

    Vyas, Giriraj; Dagar, Parveen; Sahu, Satyajit

    2018-05-01

    We have shown an exponential increase in the ratio of conductance in the on and off states of switching devices by controlling the surface morphology of the thin films for the device by depositing at different rotational speeds. The pinholes which are preferred topography on the surface at higher rotational speed give rise to higher on-off ratio of current from the devices fabricated at the speed. The lower rotational speed contributes to higher thickness of the film and hence no switching. For thicker films, the domain is formed due to phase segregation between the two components in the film, which also indicates that the film is far from thermal equilibrium. At higher speed, there is very little scope of segregation when the film is drying up. Hence, there are only few pinholes on the surface of the film which are shallow. So, the filamentary mechanism of switching in memory devices can be firmly established by varying the speed of thin film deposition which leads to phase segregation of the materials. Thus, the formation of filament can be regulated by controlling the thickness and the surface morphology.

  10. Concrete Memories

    DEFF Research Database (Denmark)

    Wiegand, Frauke Katharina

    2015-01-01

    This article traces the presence of Atlantikwall bunkers in amateur holiday snapshots and discusses the ambiguous role of the bunker site in visual cultural memory. Departing from my family’s private photo collection from twenty years of vacationing at the Danish West coast, the different mundane...... and poetic appropriations and inscriptions of the bunker site are depicted. Ranging between overlooked side presences and an overwhelming visibility, the concrete remains of fascist war architecture are involved in and motivate different sensuous experiences and mnemonic appropriations. The article meets...... the bunkers’ changing visuality and the cultural topography they both actively transform and are being transformed by through juxtaposing different acts and objects of memory over time and in different visual articulations....

  11. Treadwell Memorial

    OpenAIRE

    Downey, Frances K

    2015-01-01

    This is a memorial to gold mining in Southeast Alaska. The structure takes visitors from the Treadwell trail onto the edge of a popular local beach, reclaiming a forgotten place that was once the largest gold mine in the world. A tangible tribute to this obscure period of history, this building kindles a connection between artifacts and the community. It is a liminal space, connecting ocean and mountain, past and present, civilization and wilderness. An investigation of the Treadwell Gold...

  12. A Time-predictable Memory Network-on-Chip

    DEFF Research Database (Denmark)

    Schoeberl, Martin; Chong, David VH; Puffitsch, Wolfgang

    2014-01-01

    To derive safe bounds on worst-case execution times (WCETs), all components of a computer system need to be time-predictable: the processor pipeline, the caches, the memory controller, and memory arbitration on a multicore processor. This paper presents a solution for time-predictable memory...... arbitration and access for chip-multiprocessors. The memory network-on-chip is organized as a tree with time-division multiplexing (TDM) of accesses to the shared memory. The TDM based arbitration completely decouples processor cores and allows WCET analysis of the memory accesses on individual cores without...

  13. MoRM and Future Memory

    DEFF Research Database (Denmark)

    Rehder, Mads Middelboe; Ostrowski, Kasper

    2017-01-01

    Through a playful process which in many ways resembled devised theatre, being collaborative, script-free and improvisatory; The Museum of Random Memories was both envisioned, organized, realized, opened and documented on location at CounterPlay 2016.......Through a playful process which in many ways resembled devised theatre, being collaborative, script-free and improvisatory; The Museum of Random Memories was both envisioned, organized, realized, opened and documented on location at CounterPlay 2016....

  14. Source memory enhancement for emotional words.

    Science.gov (United States)

    Doerksen, S; Shimamura, A P

    2001-03-01

    The influence of emotional stimuli on source memory was investigated by using emotionally valenced words. The words were colored blue or yellow (Experiment 1) or surrounded by a blue or yellow frame (Experiment 2). Participants were asked to associate the words with the colors. In both experiments, emotionally valenced words elicited enhanced free recall compared with nonvalenced words; however, recognition memory was not affected. Source memory for the associated color was also enhanced for emotional words, suggesting that even memory for contextual information is benefited by emotional stimuli. This effect was not due to the ease of semantic clustering of emotional words because semantically related words were not associated with enhanced source memory, despite enhanced recall (Experiment 3). It is suggested that enhancement resulted from facilitated arousal or attention, which may act to increase organization processes important for source memory.

  15. Properties of a memory network in psychology

    Science.gov (United States)

    Wedemann, Roseli S.; Donangelo, Raul; de Carvalho, Luís A. V.

    2007-12-01

    We have previously described neurotic psychopathology and psychoanalytic working-through by an associative memory mechanism, based on a neural network model, where memory was modelled by a Boltzmann machine (BM). Since brain neural topology is selectively structured, we simulated known microscopic mechanisms that control synaptic properties, showing that the network self-organizes to a hierarchical, clustered structure. Here, we show some statistical mechanical properties of the complex networks which result from this self-organization. They indicate that a generalization of the BM may be necessary to model memory.

  16. Properties of a memory network in psychology

    International Nuclear Information System (INIS)

    Wedemann, Roseli S.; Donangelo, Raul; Carvalho, Luis A. V. de

    2007-01-01

    We have previously described neurotic psychopathology and psychoanalytic working-through by an associative memory mechanism, based on a neural network model, where memory was modelled by a Boltzmann machine (BM). Since brain neural topology is selectively structured, we simulated known microscopic mechanisms that control synaptic properties, showing that the network self-organizes to a hierarchical, clustered structure. Here, we show some statistical mechanical properties of the complex networks which result from this self-organization. They indicate that a generalization of the BM may be necessary to model memory

  17. Object recognition memory in zebrafish.

    Science.gov (United States)

    May, Zacnicte; Morrill, Adam; Holcombe, Adam; Johnston, Travis; Gallup, Joshua; Fouad, Karim; Schalomon, Melike; Hamilton, Trevor James

    2016-01-01

    The novel object recognition, or novel-object preference (NOP) test is employed to assess recognition memory in a variety of organisms. The subject is exposed to two identical objects, then after a delay, it is placed back in the original environment containing one of the original objects and a novel object. If the subject spends more time exploring one object, this can be interpreted as memory retention. To date, this test has not been fully explored in zebrafish (Danio rerio). Zebrafish possess recognition memory for simple 2- and 3-dimensional geometrical shapes, yet it is unknown if this translates to complex 3-dimensional objects. In this study we evaluated recognition memory in zebrafish using complex objects of different sizes. Contrary to rodents, zebrafish preferentially explored familiar over novel objects. Familiarity preference disappeared after delays of 5 mins. Leopard danios, another strain of D. rerio, also preferred the familiar object after a 1 min delay. Object preference could be re-established in zebra danios by administration of nicotine tartrate salt (50mg/L) prior to stimuli presentation, suggesting a memory-enhancing effect of nicotine. Additionally, exploration biases were present only when the objects were of intermediate size (2 × 5 cm). Our results demonstrate zebra and leopard danios have recognition memory, and that low nicotine doses can improve this memory type in zebra danios. However, exploration biases, from which memory is inferred, depend on object size. These findings suggest zebrafish ecology might influence object preference, as zebrafish neophobia could reflect natural anti-predatory behaviour. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Achieving Accuracy Requirements for Forest Biomass Mapping: A Data Fusion Method for Estimating Forest Biomass and LiDAR Sampling Error with Spaceborne Data

    Science.gov (United States)

    Montesano, P. M.; Cook, B. D.; Sun, G.; Simard, M.; Zhang, Z.; Nelson, R. F.; Ranson, K. J.; Lutchke, S.; Blair, J. B.

    2012-01-01

    The synergistic use of active and passive remote sensing (i.e., data fusion) demonstrates the ability of spaceborne light detection and ranging (LiDAR), synthetic aperture radar (SAR) and multispectral imagery for achieving the accuracy requirements of a global forest biomass mapping mission. This data fusion approach also provides a means to extend 3D information from discrete spaceborne LiDAR measurements of forest structure across scales much larger than that of the LiDAR footprint. For estimating biomass, these measurements mix a number of errors including those associated with LiDAR footprint sampling over regional - global extents. A general framework for mapping above ground live forest biomass (AGB) with a data fusion approach is presented and verified using data from NASA field campaigns near Howland, ME, USA, to assess AGB and LiDAR sampling errors across a regionally representative landscape. We combined SAR and Landsat-derived optical (passive optical) image data to identify forest patches, and used image and simulated spaceborne LiDAR data to compute AGB and estimate LiDAR sampling error for forest patches and 100m, 250m, 500m, and 1km grid cells. Forest patches were delineated with Landsat-derived data and airborne SAR imagery, and simulated spaceborne LiDAR (SSL) data were derived from orbit and cloud cover simulations and airborne data from NASA's Laser Vegetation Imaging Sensor (L VIS). At both the patch and grid scales, we evaluated differences in AGB estimation and sampling error from the combined use of LiDAR with both SAR and passive optical and with either SAR or passive optical alone. This data fusion approach demonstrates that incorporating forest patches into the AGB mapping framework can provide sub-grid forest information for coarser grid-level AGB reporting, and that combining simulated spaceborne LiDAR with SAR and passive optical data are most useful for estimating AGB when measurements from LiDAR are limited because they minimized

  19. Accelerating Spaceborne SAR Imaging Using Multiple CPU/GPU Deep Collaborative Computing

    Directory of Open Access Journals (Sweden)

    Fan Zhang

    2016-04-01

    Full Text Available With the development of synthetic aperture radar (SAR technologies in recent years, the huge amount of remote sensing data brings challenges for real-time imaging processing. Therefore, high performance computing (HPC methods have been presented to accelerate SAR imaging, especially the GPU based methods. In the classical GPU based imaging algorithm, GPU is employed to accelerate image processing by massive parallel computing, and CPU is only used to perform the auxiliary work such as data input/output (IO. However, the computing capability of CPU is ignored and underestimated. In this work, a new deep collaborative SAR imaging method based on multiple CPU/GPU is proposed to achieve real-time SAR imaging. Through the proposed tasks partitioning and scheduling strategy, the whole image can be generated with deep collaborative multiple CPU/GPU computing. In the part of CPU parallel imaging, the advanced vector extension (AVX method is firstly introduced into the multi-core CPU parallel method for higher efficiency. As for the GPU parallel imaging, not only the bottlenecks of memory limitation and frequent data transferring are broken, but also kinds of optimized strategies are applied, such as streaming, parallel pipeline and so on. Experimental results demonstrate that the deep CPU/GPU collaborative imaging method enhances the efficiency of SAR imaging on single-core CPU by 270 times and realizes the real-time imaging in that the imaging rate outperforms the raw data generation rate.

  20. Accelerating Spaceborne SAR Imaging Using Multiple CPU/GPU Deep Collaborative Computing.

    Science.gov (United States)

    Zhang, Fan; Li, Guojun; Li, Wei; Hu, Wei; Hu, Yuxin

    2016-04-07

    With the development of synthetic aperture radar (SAR) technologies in recent years, the huge amount of remote sensing data brings challenges for real-time imaging processing. Therefore, high performance computing (HPC) methods have been presented to accelerate SAR imaging, especially the GPU based methods. In the classical GPU based imaging algorithm, GPU is employed to accelerate image processing by massive parallel computing, and CPU is only used to perform the auxiliary work such as data input/output (IO). However, the computing capability of CPU is ignored and underestimated. In this work, a new deep collaborative SAR imaging method based on multiple CPU/GPU is proposed to achieve real-time SAR imaging. Through the proposed tasks partitioning and scheduling strategy, the whole image can be generated with deep collaborative multiple CPU/GPU computing. In the part of CPU parallel imaging, the advanced vector extension (AVX) method is firstly introduced into the multi-core CPU parallel method for higher efficiency. As for the GPU parallel imaging, not only the bottlenecks of memory limitation and frequent data transferring are broken, but also kinds of optimized strategies are applied, such as streaming, parallel pipeline and so on. Experimental results demonstrate that the deep CPU/GPU collaborative imaging method enhances the efficiency of SAR imaging on single-core CPU by 270 times and realizes the real-time imaging in that the imaging rate outperforms the raw data generation rate.

  1. The future of spaceborne altimetry. Oceans and climate change: A long-term strategy

    Science.gov (United States)

    Koblinsky, C. J. (Editor); Gaspar, P. (Editor); Lagerloef, G. (Editor)

    1992-01-01

    The ocean circulation and polar ice sheet volumes provide important memory and control functions in the global climate. Their long term variations are unknown and need to be understood before meaningful appraisals of climate change can be made. Satellite altimetry is the only method for providing global information on the ocean circulation and ice sheet volume. A robust altimeter measurement program is planned which will initiate global observations of the ocean circulation and polar ice sheets. In order to provide useful data about the climate, these measurements must be continued with unbroken coverage into the next century. Herein, past results of the role of the ocean in the climate system is summarized, near term goals are outlined, and requirements and options are presented for future altimeter missions. There are three basic scientific objectives for the program: ocean circulation; polar ice sheets; and mean sea level change. The greatest scientific benefit will be achieved with a series of dedicated high precision altimeter spacecraft, for which the choice of orbit parameters and system accuracy are unencumbered by requirements of companion instruments.

  2. The future of spaceborne altimetry. Oceans and climate change: A long-term strategy

    International Nuclear Information System (INIS)

    Koblinsky, C.J.; Gaspar, P.; Lagerloef, G.

    1992-03-01

    The ocean circulation and polar ice sheet volumes provide important memory and control functions in the global climate. Their long term variations are unknown and need to be understood before meaningful appraisals of climate change can be made. Satellite altimetry is the only method for providing global information on the ocean circulation and ice sheet volume. A robust altimeter measurement program is planned which will initiate global observations of the ocean circulation and polar ice sheets. In order to provide useful data about the climate, these measurements must be continued with unbroken coverage into the next century. Herein, past results of the role of the ocean in the climate system is summarized, near term goals are outlined, and requirements and options are presented for future altimeter missions. There are three basic scientific objectives for the program: ocean circulation; polar ice sheets; and mean sea level change. The greatest scientific benefit will be achieved with a series of dedicated high precision altimeter spacecraft, for which the choice of orbit parameters and system accuracy are unencumbered by requirements of companion instruments

  3. Transactional Memory

    CERN Document Server

    Harris, Tim; Rajwar, Ravi

    2010-01-01

    The advent of multicore processors has renewed interest in the idea of incorporating transactions into the programming model used to write parallel programs.This approach, known as transactional memory, offers an alternative, and hopefully better, way to coordinate concurrent threads. The ACI(atomicity, consistency, isolation) properties of transactions provide a foundation to ensure that concurrent reads and writes of shared data do not produce inconsistent or incorrect results. At a higher level, a computation wrapped in a transaction executes atomically - either it completes successfullyand

  4. Drosophila olfactory memory: single genes to complex neural circuits.

    Science.gov (United States)

    Keene, Alex C; Waddell, Scott

    2007-05-01

    A central goal of neuroscience is to understand how neural circuits encode memory and guide behaviour. Studying simple, genetically tractable organisms, such as Drosophila melanogaster, can illuminate principles of neural circuit organization and function. Early genetic dissection of D. melanogaster olfactory memory focused on individual genes and molecules. These molecular tags subsequently revealed key neural circuits for memory. Recent advances in genetic technology have allowed us to manipulate and observe activity in these circuits, and even individual neurons, in live animals. The studies have transformed D. melanogaster from a useful organism for gene discovery to an ideal model to understand neural circuit function in memory.

  5. Intentionally fabricated autobiographical memories

    OpenAIRE

    Justice, LV; Morrison, CM; Conway, MA

    2017-01-01

    Participants generated both autobiographical memories (AMs) that they believed to be true and intentionally fabricated autobiographical memories (IFAMs). Memories were constructed while a concurrent memory load (random 8-digit sequence) was held in mind or while there was no concurrent load. Amount and accuracy of recall of the concurrent memory load was reliably poorer following generation of IFAMs than following generation of AMs. There was no reliable effect of load on memory generation ti...

  6. STRUKTUR DAN PROSES MEMORI

    Directory of Open Access Journals (Sweden)

    Magda Bhinnety

    2015-09-01

    Full Text Available This paper describes structures and processes of human memory system according to the modal model. Sensory memory is described as the first system to store information from outside world. Short‐term memory, or now called working memory, represents a system characterized by limited ability in storing as well as retrieving information. Long‐term memory on the hand stores information larger in amount and longer than short‐term memory

  7. STRUKTUR DAN PROSES MEMORI

    OpenAIRE

    Bhinnety, Magda

    2015-01-01

    This paper describes structures and processes of human memory system according to the modal model. Sensory memory is described as the first system to store information from outside world. Short‐term memory, or now called working memory, represents a system characterized by limited ability in storing as well as retrieving information. Long‐term memory on the hand stores information larger in amount and longer than short‐term memory

  8. Electroconvulsive therapy and memory.

    Science.gov (United States)

    Harper, R G; Wiens, A N

    1975-10-01

    Recent research on the effects of electroconvulsive therapy (ECT) on memory is critically reviewed. Despite some inconsistent findings, unilateral nondominant ECT appears to affect verbal memory less than bilateral ECT. Adequate research on multiple monitored ECT is lacking. With few exceptions, the research methodologies for assessing memory have been inadequate. Many studies have confounded learning with retention, and only very recently has long term memory been adequately studied. Standardized assessment procedures for short term and long term memory are needed, in addition to more sophisticated assessment of memory processes, the duration of memory loss, and qualitative aspects of memories.

  9. Andra long term memory project - 59277

    International Nuclear Information System (INIS)

    Charton, Patrick; Boissier, Fabrice; Martin, Guillaume

    2012-01-01

    Document available in abstract form only. Full text of publication follows: Long term memory of repositories is required by safety, reversibility and social expectations. Thus Andra has implemented since 2010 a long-term memory project to reinforce and diversify its current arrangements in this field, as well as to explore opportunities to extend memory keeping over thousands years. The project includes opportunity studies of dedicated facilities. The 'Ecotheque' and 'Geotheque' projects contribute to memory respectively through environmental and geological samples preservation. The options of creating (i) an archive centre for Andra's interim and permanent archives, (ii) an artist center to study the contribution of arts to memory preservation, (iii) a museum of radioactive waste disposal history and technology (radium industry..., sea disposal, current solutions...) are considered. Other studies provided by the project examine our heritage. This includes the continuity of languages and symbolic systems, the continuity of writing and engraving methods, the archaeology of landscapes (memory of the earths evolution, multi-century memory of industrial and agricultural landscapes), the archaeology practices (how might a future archaeologist be interested in our current activity?), the preservation of historical sites and industrial memory, the continuity of institutional organizations, the memory and history of science evolution as well as broad history

  10. Detailed sensory memory, sloppy working memory

    NARCIS (Netherlands)

    Sligte, I.G.; Vandenbroucke, A.R.E.; Scholte, H.S.; Lamme, V.A.F.

    2010-01-01

    Visual short-term memory (VSTM) enables us to actively maintain information in mind for a brief period of time after stimulus disappearance. According to recent studies, VSTM consists of three stages - iconic memory, fragile VSTM, and visual working memory - with increasingly stricter capacity

  11. Interference Mitigation Technique Using Active Spaceborne Sensor Antenna in EESS (Active) and Space Research Service (Active) for Use in 500 MHz Bandwidth Near 9.6 GHz

    Science.gov (United States)

    Huneycutt, Bryan L.

    2005-01-01

    This document presents an interference mitigation technique using the active spaceborne sensor SAR3 antenna in the Earth Exploration-Satellite Service (active) and Space Research Service (active) for use in a 500 MHz bandwidth near 9.6 GHz. The purpose of the document is present antenna designs which offer lower sidelobes and faster rolloff in the sidelobes which in turn mitigates the interference to other services from the EESS (active) and SRS (active) sensors.

  12. Optical memory

    Science.gov (United States)

    Mao, Samuel S; Zhang, Yanfeng

    2013-07-02

    Optical memory comprising: a semiconductor wire, a first electrode, a second electrode, a light source, a means for producing a first voltage at the first electrode, a means for producing a second voltage at the second electrode, and a means for determining the presence of an electrical voltage across the first electrode and the second electrode exceeding a predefined voltage. The first voltage, preferably less than 0 volts, different from said second voltage. The semiconductor wire is optically transparent and has a bandgap less than the energy produced by the light source. The light source is optically connected to the semiconductor wire. The first electrode and the second electrode are electrically insulated from each other and said semiconductor wire.

  13. Mapping alteration using imagery from the Tiangong-1 hyperspectral spaceborne system: Example for the Jintanzi gold province, China

    Science.gov (United States)

    Liu, Lei; Feng, Jilu; Rivard, Benoit; Xu, Xinliang; Zhou, Jun; Han, Ling; Yang, Junlu; Ren, Guangli

    2018-02-01

    The Tiangong-1 Hyperspectral Imager (HSI) is a relatively new spaceborne hyperspectral remote sensing system that was launched by the Chinese government on September 29th 2011. The system has 64 shortwave infrared (SWIR) spectral bands (1000-2500 nm) and imagery is at a spatial resolution of 20 m. This study represents an evaluation of Tiangong-1 data for the production of alteration mineral maps. Alteration mineral maps resulting from the analysis of Tiangong-1 HSI data and airborne SASI (Shortwave infrared Airborne Spectrographic Imager) data are compared for the Jintanzi area, Beishan, Gansu province, northwest China where gold bearing veins are documented. The results illustrate the detection of muscovite, kaolinite, chlorite, epidote, calcite and dolomite from Tiangong-1 HSI data and most anomalies seen in the airborne SASI data are captured. The Tiangong-1 data appears to be well suited for the detection of surface mineralogy in support of regional mapping and exploration. The data complements that which will be offered by the Chinese GF-5 Hyperspectral Imager and the German EnMAP system, both scheduled for launch in 2018.

  14. Identification of glacier motion and potentially dangerous glacial lakes in the Mt. Everest region/Nepal using spaceborne imagery

    Directory of Open Access Journals (Sweden)

    T. Bolch

    2008-12-01

    Full Text Available Failures of glacial lake dams can cause outburst floods and represents a serious hazard. The potential danger of outburst floods depends on various factors like the lake's area and volume, glacier change, morphometry of the glacier and its surrounding moraines and valley, and glacier velocity. Remote sensing offers an efficient tool for displacement calculations and risk assessment of the identification of potentially dangerous glacial lakes (PDGLs and is especially helpful for remote mountainous areas. Not all important parameters can, however, be obtained using spaceborne imagery. Additional interpretation by an expert is required. ASTER data has a suitable accuracy to calculate surface velocity. Ikonos data offers more detail but requires more effort for rectification. All investigated debris-covered glacier tongues show areas with no or very slow movement rates. From 1962 to 2003 the number and area of glacial lakes increased, dominated by the occurrence and almost linear areal expansion of the moraine-dammed lakes, like the Imja Lake. Although the Imja Lake will probably still grow in the near future, the risk of an outburst flood (GLOF is considered not higher than for other glacial lakes in the area. Potentially dangerous lakes and areas of lake development are identified. There is a high probability of further lake development at Khumbu Glacier, but a low one at Lhotse Glacier.

  15. First Spaceborne GNSS-Reflectometry Observations of Hurricanes From the UK TechDemoSat-1 Mission

    Science.gov (United States)

    Foti, Giuseppe; Gommenginger, Christine; Srokosz, Meric

    2017-12-01

    We present the first examples of Global Navigation Satellite Systems-Reflectometry (GNSS-R) observations of hurricanes using spaceborne data from the UK TechDemoSat-1 (TDS-1) mission. We confirm that GNSS-R signals can detect ocean condition changes in very high near-surface ocean wind associated with hurricanes. TDS-1 GNSS-R reflections were collocated with International Best Track Archive for Climate Stewardship (IBTrACS) hurricane data, MetOp ASCAT A/B scatterometer winds, and two reanalysis products. Clear variations of GNSS-R reflected power (σ0) are observed as reflections travel through hurricanes, in some cases up to and through the eye wall. The GNSS-R reflected power is tentatively inverted to estimate wind speed using the TDS-1 baseline wind retrieval algorithm developed for low to moderate winds. Despite this, TDS-1 GNSS-R winds through the hurricanes show closer agreement with IBTrACS estimates than winds provided by scatterometers and reanalyses. GNSS-R wind profiles show realistic spatial patterns and sharp gradients that are consistent with expected structures around the eye of tropical cyclones.

  16. Thermal analysis of a prototype cryogenic polarization modulator for use in a space-borne CMB polarization experiment

    Science.gov (United States)

    Iida, T.; Sakurai, Y.; Matsumura, T.; Sugai, H.; Imada, H.; Kataza, H.; Ohsaki, H.; Hazumi, M.; Katayama, N.; Yamamoto, R.; Utsunomiya, S.; Terao, Y.

    2017-12-01

    We report a thermal analysis of a polarization modulator unit (PMU) for use in a space-borne cosmic microwave background (CMB) project. A measurement of the CMB polarization allows us to probe the physics of early universe, and that is the best method to test the cosmic inflation experimentally. One of the key instruments for this science is to use a halfwave plate (HWP) based polarization modulator. The HWP is required to rotate continuously at about 1 Hz below 10 K to minimize its own thermal emission to a detector system. The rotating HWP system at the cryogenic environment can be realized by using a superconducting magnetic bearing (SMB) without significant heat dissipation by mechanical friction. While the SMB achieves the smooth rotation due to the contactless bearing, an estimation of a levitating HWP temperature becomes a challenge. We manufactured a one-eighth scale prototype model of PMU and built a thermal model. We verified our thermal model with the experimental data. We forecasted the projected thermal performance of PMU for a full-scale model based on the thermal model. From this analysis, we discuss the design requirement toward constructing the full-scale model for use in a space environment such as a future CMB satellite mission, LiteBIRD.

  17. A Large Underestimate of Formic Acid from Tropical Fires: Constraints from Space-Borne Measurements.

    Science.gov (United States)

    Chaliyakunnel, S; Millet, D B; Wells, K C; Cady-Pereira, K E; Shephard, M W

    2016-06-07

    Formic acid (HCOOH) is one of the most abundant carboxylic acids and a dominant source of atmospheric acidity. Recent work indicates a major gap in the HCOOH budget, with atmospheric concentrations much larger than expected from known sources. Here, we employ recent space-based observations from the Tropospheric Emission Spectrometer with the GEOS-Chem atmospheric model to better quantify the HCOOH source from biomass burning, and assess whether fire emissions can help close the large budget gap for this species. The space-based data reveal a severe model HCOOH underestimate most prominent over tropical burning regions, suggesting a major missing source of organic acids from fires. We develop an approach for inferring the fractional fire contribution to ambient HCOOH and find, based on measurements over Africa, that pyrogenic HCOOH:CO enhancement ratios are much higher than expected from direct emissions alone, revealing substantial secondary organic acid production in fire plumes. Current models strongly underestimate (by 10 ± 5 times) the total primary and secondary HCOOH source from African fires. If a 10-fold bias were to extend to fires in other regions, biomass burning could produce 14 Tg/a of HCOOH in the tropics or 16 Tg/a worldwide. However, even such an increase would only represent 15-20% of the total required HCOOH source, implying the existence of other larger missing sources.

  18. Memory, microprocessor, and ASIC

    CERN Document Server

    Chen, Wai-Kai

    2003-01-01

    System Timing. ROM/PROM/EPROM. SRAM. Embedded Memory. Flash Memories. Dynamic Random Access Memory. Low-Power Memory Circuits. Timing and Signal Integrity Analysis. Microprocessor Design Verification. Microprocessor Layout Method. Architecture. ASIC Design. Logic Synthesis for Field Programmable Gate Array (EPGA) Technology. Testability Concepts and DFT. ATPG and BIST. CAD Tools for BIST/DFT and Delay Faults.

  19. Infant Visual Recognition Memory

    Science.gov (United States)

    Rose, Susan A.; Feldman, Judith F.; Jankowski, Jeffery J.

    2004-01-01

    Visual recognition memory is a robust form of memory that is evident from early infancy, shows pronounced developmental change, and is influenced by many of the same factors that affect adult memory; it is surprisingly resistant to decay and interference. Infant visual recognition memory shows (a) modest reliability, (b) good discriminant…

  20. Episodic-like memory in zebrafish.

    Science.gov (United States)

    Hamilton, Trevor J; Myggland, Allison; Duperreault, Erika; May, Zacnicte; Gallup, Joshua; Powell, Russell A; Schalomon, Melike; Digweed, Shannon M

    2016-11-01

    Episodic-like memory tests often aid in determining an animal's ability to recall the what, where, and which (context) of an event. To date, this type of memory has been demonstrated in humans, wild chacma baboons, corvids (Scrub jays), humming birds, mice, rats, Yucatan minipigs, and cuttlefish. The potential for this type of memory in zebrafish remains unexplored even though they are quickly becoming an essential model organism for the study of a variety of human cognitive and mental disorders. Here we explore the episodic-like capabilities of zebrafish (Danio rerio) in a previously established mammalian memory paradigm. We demonstrate that when zebrafish were presented with a familiar object in a familiar context but a novel location within that context, they spend more time in the novel quadrant. Thus, zebrafish display episodic-like memory as they remember what object they saw, where they saw it (quadrant location), and on which occasion (yellow or blue walls) it was presented.

  1. Nanoscale memory devices

    International Nuclear Information System (INIS)

    Chung, Andy; Deen, Jamal; Lee, Jeong-Soo; Meyyappan, M

    2010-01-01

    This article reviews the current status and future prospects for the use of nanomaterials and devices in memory technology. First, the status and continuing scaling trends of the flash memory are discussed. Then, a detailed discussion on technologies trying to replace flash in the near-term is provided. This includes phase change random access memory, Fe random access memory and magnetic random access memory. The long-term nanotechnology prospects for memory devices include carbon-nanotube-based memory, molecular electronics and memristors based on resistive materials such as TiO 2 . (topical review)

  2. Episodic memory in aspects of large-scale brain networks

    Science.gov (United States)

    Jeong, Woorim; Chung, Chun Kee; Kim, June Sic

    2015-01-01

    Understanding human episodic memory in aspects of large-scale brain networks has become one of the central themes in neuroscience over the last decade. Traditionally, episodic memory was regarded as mostly relying on medial temporal lobe (MTL) structures. However, recent studies have suggested involvement of more widely distributed cortical network and the importance of its interactive roles in the memory process. Both direct and indirect neuro-modulations of the memory network have been tried in experimental treatments of memory disorders. In this review, we focus on the functional organization of the MTL and other neocortical areas in episodic memory. Task-related neuroimaging studies together with lesion studies suggested that specific sub-regions of the MTL are responsible for specific components of memory. However, recent studies have emphasized that connectivity within MTL structures and even their network dynamics with other cortical areas are essential in the memory process. Resting-state functional network studies also have revealed that memory function is subserved by not only the MTL system but also a distributed network, particularly the default-mode network (DMN). Furthermore, researchers have begun to investigate memory networks throughout the entire brain not restricted to the specific resting-state network (RSN). Altered patterns of functional connectivity (FC) among distributed brain regions were observed in patients with memory impairments. Recently, studies have shown that brain stimulation may impact memory through modulating functional networks, carrying future implications of a novel interventional therapy for memory impairment. PMID:26321939

  3. Episodic memory in aspects of large-scale brain networks

    Directory of Open Access Journals (Sweden)

    Woorim eJeong

    2015-08-01

    Full Text Available Understanding human episodic memory in aspects of large-scale brain networks has become one of the central themes in neuroscience over the last decade. Traditionally, episodic memory was regarded as mostly relying on medial temporal lobe (MTL structures. However, recent studies have suggested involvement of more widely distributed cortical network and the importance of its interactive roles in the memory process. Both direct and indirect neuro-modulations of the memory network have been tried in experimental treatments of memory disorders. In this review, we focus on the functional organization of the MTL and other neocortical areas in episodic memory. Task-related neuroimaging studies together with lesion studies suggested that specific sub-regions of the MTL are responsible for specific components of memory. However, recent studies have emphasized that connectivity within MTL structures and even their network dynamics with other cortical areas are essential in the memory process. Resting-state functional network studies also have revealed that memory function is subserved by not only the MTL system but also a distributed network, particularly the default-mode network. Furthermore, researchers have begun to investigate memory networks throughout the entire brain not restricted to the specific resting-state network. Altered patterns of functional connectivity among distributed brain regions were observed in patients with memory impairments. Recently, studies have shown that brain stimulation may impact memory through modulating functional networks, carrying future implications of a novel interventional therapy for memory impairment.

  4. Investigation of fast initialization of spacecraft bubble memory systems

    Science.gov (United States)

    Looney, K. T.; Nichols, C. D.; Hayes, P. J.

    1984-01-01

    Bubble domain technology offers significant improvement in reliability and functionality for spacecraft onboard memory applications. In considering potential memory systems organizations, minimization of power in high capacity bubble memory systems necessitates the activation of only the desired portions of the memory. In power strobing arbitrary memory segments, a capability of fast turn on is required. Bubble device architectures, which provide redundant loop coding in the bubble devices, limit the initialization speed. Alternate initialization techniques are investigated to overcome this design limitation. An initialization technique using a small amount of external storage is demonstrated.

  5. Visual memory needs categories

    OpenAIRE

    Olsson, Henrik; Poom, Leo

    2005-01-01

    Capacity limitations in the way humans store and process information in working memory have been extensively studied, and several memory systems have been distinguished. In line with previous capacity estimates for verbal memory and memory for spatial information, recent studies suggest that it is possible to retain up to four objects in visual working memory. The objects used have typically been categorically different colors and shapes. Because knowledge about categories is stored in long-t...

  6. Non-volatile memories

    CERN Document Server

    Lacaze, Pierre-Camille

    2014-01-01

    Written for scientists, researchers, and engineers, Non-volatile Memories describes the recent research and implementations in relation to the design of a new generation of non-volatile electronic memories. The objective is to replace existing memories (DRAM, SRAM, EEPROM, Flash, etc.) with a universal memory model likely to reach better performances than the current types of memory: extremely high commutation speeds, high implantation densities and retention time of information of about ten years.

  7. Memory: sins and virtues

    OpenAIRE

    Schacter, Daniel L.

    2013-01-01

    Memory plays an important role in everyday life but does not provide an exact and unchanging record of experience: research has documented that memory is a constructive process that is subject to a variety of errors and distortions. Yet these memory “sins” also reflect the operation of adaptive aspects of memory. Memory can thus be characterized as an adaptive constructive process, which plays a functional role in cognition but produces distortions, errors, or illusions as a consequence of d...

  8. Increment memory module for spectrometric data recording

    International Nuclear Information System (INIS)

    Zhuchkov, A.A.; Myagkikh, A.I.

    1988-01-01

    Incremental memory unit designed to input differential energy spectra of nuclear radiation is described. ROM application as incremental device has allowed to reduce the number of elements and do simplify information readout from the unit. 12-bit 2048 channels present memory unit organization. The device is connected directly with the bus of microprocessor systems similar to KR 580. Incrementation maximal time constitutes 3 mks. It is possible to use this unit in multichannel counting mode

  9. Salam Memorial

    CERN Document Server

    Rubbia, Carlo

    1997-01-01

    by T.W.B. KIBBLE / Blackett Laboratory, Imperial College, London. Recollections of Abdus Salam at Imperial College I shall give a personal account of Professor Salam's life and work from the perspective of a colleague at Imperial College, concentrating particularly but not exclusively on the period leading up to the discovery of the electro-weak theory. If necessary I could perhaps give more detail, but only once I have given more thought to what ground I shall cover. by Sheldon Lee GLASHOW / Harvard University, Cambridge, MA, USA. Memories of Abdus Salam. My interactions with Abdus Salam, weak as they have been, extended over five decades. I regret that we never once collaborated in print or by correspondence. I visited Abdus only twice in London and twice again in Trieste, and met him at the occasional conference or summer school. Our face-to-face encounters could be counted on one's fingers and toes, but we became the best of friends. Others will discuss Abdus as an inspiring teacher, as a great scientist,...

  10. Review: Attention and Memory in Autism

    Directory of Open Access Journals (Sweden)

    Arash Mirab-Zadeh

    2001-12-01

    Full Text Available Many investigations have documented about attentional and memorial abnormality in individuals with autism. This study is summary of recent researches about alternations of attention and memory in autism. The most important changes of attention in autism are: 1 Arousal modulatory system dysfunction, leading to fluctuations between states over and under arousal. 2 Reduction of orienting and processing of novel stimuli. 3 Over focused attention, responding to only a subset of environmental cues. 4 Deficit in shifting attention, leading to difficulty moving their attention from one special location to another. The most important changes of memory in autism are: 1 Good rote memory 2 Cued recall is significantly better than free recall 3 Deficit in working memory 4 Deficit in implicit and explicit memory 5 Deficit in verbal memory about material that requires further encoding, organization or use of meaning or semantic cues for recalling 6 High functioning memory in some of the patients for example ability to read well, singing or recognizing musical pieces

  11. A short review of memory research

    Directory of Open Access Journals (Sweden)

    Igor Areh

    2004-09-01

    Full Text Available Scientific research on memory began at the end of 19th century with studies of semantic and/or long term memory. In most cases memory was interpreted as a storehouse for various data and the quality of the storehouse was usually defined by a quantity of recalled data. The research work was concentrated on specificity of the connection between memory and learning. At that time few authors developed theories which were rare, uncommon and before their time (e.g.: Bartlett, Ribot, Freud. Even after 20th century, when behavioural stimulus-response approach began to dominate, the measure of memory quality was still the quantity of memory recall. In the 1960th the rise of cognitive psychology began, the computer metaphor was born and finally the behavioural comprehension of cognitive system was surpassed. Cognitive system was understood as a computer-like interface between an organism and environment. In recent years the computer metaphor is no longer dominant. New and efficient concepts are moving forward. Quantity of data recall, as the measure of memory quality, is not so important any more – attention is focused on accuracy of memory recall.

  12. From Augustine of Hippo's Memory Systems to Our Modern Taxonomy in Cognitive Psychology and Neuroscience of Memory: A 16-Century Nap of Intuition before Light of Evidence.

    Science.gov (United States)

    Cassel, Jean-Christophe; Cassel, Daniel; Manning, Lilianne

    2013-03-01

    Over the last half century, neuropsychologists, cognitive psychologists and cognitive neuroscientists interested in human memory have accumulated evidence showing that there is not one general memory function but a variety of memory systems deserving distinct (but for an organism, complementary) functional entities. The first attempts to organize memory systems within a taxonomic construct are often traced back to the French philosopher Maine de Biran (1766-1824), who, in his book first published in 1803, distinguished mechanical memory, sensitive memory and representative memory, without, however, providing any experimental evidence in support of his view. It turns out, however, that what might be regarded as the first elaborated taxonomic proposal is 14 centuries older and is due to Augustine of Hippo (354-430), also named St Augustine, who, in Book 10 of his Confessions, by means of an introspective process that did not aim at organizing memory systems, nevertheless distinguished and commented on sensible memory, intellectual memory, memory of memories, memory of feelings and passion, and memory of forgetting. These memories were envisaged as different and complementary instances. In the current study, after a short biographical synopsis of St Augustine, we provide an outline of the philosopher's contribution, both in terms of questions and answers, and focus on how this contribution almost perfectly fits with several viewpoints of modern psychology and neuroscience of memory about human memory functions, including the notion that episodic autobiographical memory stores events of our personal history in their what, where and when dimensions, and from there enables our mental time travel. It is not at all meant that St Augustine's elaboration was the basis for the modern taxonomy, but just that the similarity is striking, and that the architecture of our current viewpoints about memory systems might have preexisted as an outstanding intuition in the philosopher

  13. Towards ground-truthing of spaceborne estimates of above-ground biomass and leaf area index in tropical rain forests

    Science.gov (United States)

    Köhler, P.; Huth, A.

    2010-05-01

    The canopy height of forests is a key variable which can be obtained using air- or spaceborne remote sensing techniques such as radar interferometry or lidar. If new allometric relationships between canopy height and the biomass stored in the vegetation can be established this would offer the possibility for a global monitoring of the above-ground carbon content on land. In the absence of adequate field data we use simulation results of a tropical rain forest growth model to propose what degree of information might be generated from canopy height and thus to enable ground-truthing of potential future satellite observations. We here analyse the correlation between canopy height in a tropical rain forest with other structural characteristics, such as above-ground biomass (AGB) (and thus carbon content of vegetation) and leaf area index (LAI). The process-based forest growth model FORMIND2.0 was applied to simulate (a) undisturbed forest growth and (b) a wide range of possible disturbance regimes typically for local tree logging conditions for a tropical rain forest site on Borneo (Sabah, Malaysia) in South-East Asia. It is found that for undisturbed forest and a variety of disturbed forests situations AGB can be expressed as a power-law function of canopy height h (AGB=a·hb) with an r2~60% for a spatial resolution of 20 m×20 m (0.04 ha, also called plot size). The regression is becoming significant better for the hectare wide analysis of the disturbed forest sites (r2=91%). There seems to exist no functional dependency between LAI and canopy height, but there is also a linear correlation (r2~60%) between AGB and the area fraction in which the canopy is highly disturbed. A reasonable agreement of our results with observations is obtained from a comparison of the simulations with permanent sampling plot data from the same region and with the large-scale forest inventory in Lambir. We conclude that the spaceborne remote sensing techniques have the potential to

  14. Visual Memories Bypass Normalization.

    Science.gov (United States)

    Bloem, Ilona M; Watanabe, Yurika L; Kibbe, Melissa M; Ling, Sam

    2018-05-01

    How distinct are visual memory representations from visual perception? Although evidence suggests that briefly remembered stimuli are represented within early visual cortices, the degree to which these memory traces resemble true visual representations remains something of a mystery. Here, we tested whether both visual memory and perception succumb to a seemingly ubiquitous neural computation: normalization. Observers were asked to remember the contrast of visual stimuli, which were pitted against each other to promote normalization either in perception or in visual memory. Our results revealed robust normalization between visual representations in perception, yet no signature of normalization occurring between working memory stores-neither between representations in memory nor between memory representations and visual inputs. These results provide unique insight into the nature of visual memory representations, illustrating that visual memory representations follow a different set of computational rules, bypassing normalization, a canonical visual computation.

  15. Stochastic memory: getting memory out of noise

    Science.gov (United States)

    Stotland, Alexander; di Ventra, Massimiliano

    2011-03-01

    Memory circuit elements, namely memristors, memcapacitors and meminductors, can store information without the need of a power source. These systems are generally defined in terms of deterministic equations of motion for the state variables that are responsible for memory. However, in real systems noise sources can never be eliminated completely. One would then expect noise to be detrimental for memory. Here, we show that under specific conditions on the noise intensity memory can actually be enhanced. We illustrate this phenomenon using a physical model of a memristor in which the addition of white noise into the state variable equation improves the memory and helps the operation of the system. We discuss under which conditions this effect can be realized experimentally, discuss its implications on existing memory systems discussed in the literature, and also analyze the effects of colored noise. Work supported in part by NSF.

  16. Space-borne observation of mesospheric bore by Visible and near Infrared Spectral Imager onboard the International Space Station

    Science.gov (United States)

    Hozumi, Y.; Saito, A.; Sakanoi, T.; Yamazaki, A.; Hosokawa, K.

    2017-12-01

    Mesospheric bores were observed by Visible and near Infrared Spectral Imager (VISI) of the ISS-IMAP mission (Ionosphere, Mesosphere, upper Atmosphere and Plasmasphere mapping mission from the International Space Station) in O2 airglow at 762 nm wavelength. The mesospheric bore is moving front of sharp jump followed by undulations or turbulence in the mesopause region. Since previous studies of mesospheric bore were mainly based on ground-based airglow imaging that is limited in field-of-view and observing site, little is known about its horizontal extent and global behavior. Space-borne imaging by ISS-IMAP/VISI provides an opportunity to study the mesospheric bore with a wide field-of-view and global coverage. A mesospheric bore was captured by VISI in two consecutive paths on 9 July 2015 over the south of African continent (48ºS - 54ºS and 15ºE). The wave front aligned with south-north direction and propagated to west. The phase velocity and wave length of the following undulation were estimated to 100 m/s and 30 km, respectively. Those parameters are similar to those reported by previous studies. 30º anti-clockwise rotation of the wave front was recognized in 100 min. Another mesospheric bore was captured on 9 May 2013 over the south Atlantic ocean (35ºS - 43ºS and 24ºW - 1ºE) with more than 2,200 km horizontal extent of wave front. The wave front aligned with southeast-northwest direction. Because the following undulation is recognized in the southwest side of the wave front, it is estimated to propagate to northeast direction. The wave front was modulated with 1,000 km wave length. This modulation implies inhomogeneity of the phase velocity.

  17. Three-dimensional fusion of spaceborne and ground radar reflectivity data using a neural network-based approach

    Science.gov (United States)

    Kou, Leilei; Wang, Zhuihui; Xu, Fen

    2018-03-01

    The spaceborne precipitation radar onboard the Tropical Rainfall Measuring Mission satellite (TRMM PR) can provide good measurement of the vertical structure of reflectivity, while ground radar (GR) has a relatively high horizontal resolution and greater sensitivity. Fusion of TRMM PR and GR reflectivity data may maximize the advantages from both instruments. In this paper, TRMM PR and GR reflectivity data are fused using a neural network (NN)-based approach. The main steps included are: quality control of TRMM PR and GR reflectivity data; spatiotemporal matchup; GR calibration bias correction; conversion of TRMM PR data from Ku to S band; fusion of TRMM PR and GR reflectivity data with an NN method; interpolation of reflectivity data that are below PR's sensitivity; blind areas compensation with a distance weighting-based merging approach; combination of three types of data: data with the NN method, data below PR's sensitivity and data within compensated blind areas. During the NN fusion step, the TRMM PR data are taken as targets of the training NNs, and gridded GR data after horizontal downsampling at different heights are used as the input. The trained NNs are then used to obtain 3D high-resolution reflectivity from the original GR gridded data. After 3D fusion of the TRMM PR and GR reflectivity data, a more complete and finer-scale 3D radar reflectivity dataset incorporating characteristics from both the TRMM PR and GR observations can be obtained. The fused reflectivity data are evaluated based on a convective precipitation event through comparison with the high resolution TRMM PR and GR data with an interpolation algorithm.

  18. Simulation of space-borne tsunami detection using GNSS-Reflectometry applied to tsunamis in the Indian Ocean

    Directory of Open Access Journals (Sweden)

    R. Stosius

    2010-06-01

    Full Text Available Within the German-Indonesian Tsunami Early Warning System project GITEWS (Rudloff et al., 2009, a feasibility study on a future tsunami detection system from space has been carried out. The Global Navigation Satellite System Reflectometry (GNSS-R is an innovative way of using reflected GNSS signals for remote sensing, e.g. sea surface altimetry. In contrast to conventional satellite radar altimetry, multiple height measurements within a wide field of view can be made simultaneously. With a dedicated Low Earth Orbit (LEO constellation of satellites equipped with GNSS-R, densely spaced sea surface height measurements could be established to detect tsunamis. This simulation study compares the Walker and the meshed comb constellation with respect to their global reflection point distribution. The detection performance of various LEO constellation scenarios with GPS, GLONASS and Galileo as signal sources is investigated. The study concentrates on the detection performance for six historic tsunami events in the Indian Ocean generated by earthquakes of different magnitudes, as well as on different constellation types and orbit parameters. The GNSS-R carrier phase is compared with the PARIS or code altimetry approach. The study shows that Walker constellations have a much better reflection point distribution compared to the meshed comb constellation. Considering simulation assumptions and assuming technical feasibility it can be demonstrated that strong tsunamis with magnitudes (M ≥8.5 can be detected with certainty from any orbit altitude within 15–25 min by a 48/8 or 81/9 Walker constellation if tsunami waves of 20 cm or higher can be detected by space-borne GNSS-R. The carrier phase approach outperforms the PARIS altimetry approach especially at low orbit altitudes and for a low number of LEO satellites.

  19. Unsupervised SBAS-DInSAR Processing of Space-borne SAR data for Earth Surface Displacement Time Series Generation

    Science.gov (United States)

    Casu, F.; de Luca, C.; Lanari, R.; Manunta, M.; Zinno, I.

    2016-12-01

    During the last 25 years, the Differential Synthetic Aperture Radar Interferometry (DInSAR) has played an important role for understanding the Earth's surface deformation and its dynamics. In particular, the large collections of SAR data acquired by a number of space-borne missions (ERS, ENVISAT, ALOS, RADARSAT, TerraSAR-X, COSMO-SkyMed) have pushed toward the development of advanced DInSAR techniques for monitoring the temporal evolution of the ground displacements with an high spatial density. Moreover, the advent of the Copernicus Sentinel-1 (S1) constellation is providing a further increase in the SAR data flow available to the Earth science community, due to its characteristics of global coverage strategy and free and open access data policy. Therefore, managing and storing such a huge amount of data, processing it in an effcient way and maximizing the available archives exploitation are becoming high priority issues. In this work we present some recent advances in the DInSAR field for dealing with the effective exploitation of the present and future SAR data archives. In particular, an efficient parallel SBAS implementation (namely P-SBAS) that takes benefit from high performance computing is proposed. Then, the P-SBAS migration to the emerging Cloud Computing paradigm is shown, together with extensive tests carried out in the Amazon's Elastic Cloud Compute (EC2) infrastructure. Finally, the integration of the P-SBAS processing chain within the ESA Geohazards Exploitation Platform (GEP), for setting up operational on-demand and systematic web tools, open to every user, aimed at automatically processing stacks of SAR data for the generation of SBAS displacement time series, is also illustrated. A number of experimental results obtained by using the ERS, ENVISAT and S1 data in areas characterized by volcanic, seismic and anthropogenic phenomena will be shown. This work is partially supported by: the DPC-CNR agreement, the EPOS-IP project and the ESA GEP project.

  20. Detailed Sensory Memory, Sloppy Working Memory

    OpenAIRE

    Sligte, Ilja G.; Vandenbroucke, Annelinde R. E.; Scholte, H. Steven; Lamme, Victor A. F.

    2010-01-01

    Visual short-term memory (VSTM) enables us to actively maintain information in mind for a brief period of time after stimulus disappearance. According to recent studies, VSTM consists of three stages - iconic memory, fragile VSTM, and visual working memory - with increasingly stricter capacity limits and progressively longer lifetimes. Still, the resolution (or amount of visual detail) of each VSTM stage has remained unexplored and we test this in the present study. We presented people with a...

  1. The continental source of glyoxal estimated by the synergistic use of spaceborne measurements and inverse modelling

    Directory of Open Access Journals (Sweden)

    A. Richter

    2009-11-01

    Full Text Available Tropospheric glyoxal and formaldehyde columns retrieved from the SCIAMACHY satellite instrument in 2005 are used with the IMAGESv2 global chemistry-transport model and its adjoint in a two-compound inversion scheme designed to estimate the continental source of glyoxal. The formaldehyde observations provide an important constraint on the production of glyoxal from isoprene in the model, since the degradation of isoprene constitutes an important source of both glyoxal and formaldehyde. Current modelling studies underestimate largely the observed glyoxal satellite columns, pointing to the existence of an additional land glyoxal source of biogenic origin. We include an extra glyoxal source in the model and we explore its possible distribution and magnitude through two inversion experiments. In the first case, the additional source is represented as a direct glyoxal emission, and in the second, as a secondary formation through the oxidation of an unspecified glyoxal precursor. Besides this extra source, the inversion scheme optimizes the primary glyoxal and formaldehyde emissions, as well as their secondary production from other identified non-methane volatile organic precursors of anthropogenic, pyrogenic and biogenic origin.

    In the first inversion experiment, the additional direct source, estimated at 36 Tg/yr, represents 38% of the global continental source, whereas the contribution of isoprene is equally important (30%, the remainder being accounted for by anthropogenic (20% and pyrogenic fluxes. The inversion succeeds in reducing the underestimation of the glyoxal columns by the model, but it leads to a severe overestimation of glyoxal surface concentrations in comparison with in situ measurements. In the second scenario, the inferred total global continental glyoxal source is estimated at 108 Tg/yr, almost two times higher than the global a priori source. The extra secondary source is the largest contribution to the global glyoxal

  2. Detailed sensory memory, sloppy working memory.

    Science.gov (United States)

    Sligte, Ilja G; Vandenbroucke, Annelinde R E; Scholte, H Steven; Lamme, Victor A F

    2010-01-01

    Visual short-term memory (VSTM) enables us to actively maintain information in mind for a brief period of time after stimulus disappearance. According to recent studies, VSTM consists of three stages - iconic memory, fragile VSTM, and visual working memory - with increasingly stricter capacity limits and progressively longer lifetimes. Still, the resolution (or amount of visual detail) of each VSTM stage has remained unexplored and we test this in the present study. We presented people with a change detection task that measures the capacity of all three forms of VSTM, and we added an identification display after each change trial that required people to identify the "pre-change" object. Accurate change detection plus pre-change identification requires subjects to have a high-resolution representation of the "pre-change" object, whereas change detection or identification only can be based on the hunch that something has changed, without exactly knowing what was presented before. We observed that people maintained 6.1 objects in iconic memory, 4.6 objects in fragile VSTM, and 2.1 objects in visual working memory. Moreover, when people detected the change, they could also identify the pre-change object on 88% of the iconic memory trials, on 71% of the fragile VSTM trials and merely on 53% of the visual working memory trials. This suggests that people maintain many high-resolution representations in iconic memory and fragile VSTM, but only one high-resolution object representation in visual working memory.

  3. The Development of Organized Rehearsal

    Science.gov (United States)

    Weist, Richard M.; Crawford, Jack

    1977-01-01

    In a study of development of organization strategies in rehearsal processes, children in the first, third, and fifth grades were exposed to a memory task which involved multiple overt rehearsal and recall phases. (SB)

  4. Advance Organizers: Concret Versus Abstract.

    Science.gov (United States)

    Corkill, Alice J.; And Others

    1988-01-01

    Two experiments examined the relative effects of concrete and abstract advance organizers on students' memory for subsequent prose. Results of the experiments are discussed in terms of the memorability, familiarity, and visualizability of concrete and abstract verbal materials. (JD)

  5. Memory NK cells: why do they reside in the liver?

    Science.gov (United States)

    Jiang, Xiaojun; Chen, Yonglin; Peng, Hui; Tian, Zhigang

    2013-05-01

    Immune memory is the hallmark of adaptive immunity. However, recent studies have shown that natural killer (NK) cells, key components of the innate immune system, also mediate memory responses in mice and humans. Strikingly, memory NK cells were liver-resident in some models, raising the question as to whether the liver is a special organ for the acquisition of NK cell memory. Here, we review the characteristics of NK cell memory by summarizing recent progress and discuss how the liver may generate both the initiation and the recall phase of memory. We propose that the liver may have unique precursors for memory NK cells, which are developmentally distinct from NK cells derived from bone marrow.

  6. Severity of explicit memory impairment due to Alzheimer's disease improves effectiveness of implicit learning.

    Science.gov (United States)

    Klimkowicz-Mrowiec, Aleksandra; Slowik, Agnieszka; Krzywoszanski, Lukasz; Herzog-Krzywoszanska, Radosława; Szczudlik, Andrzej

    2008-04-01

    Consistent evidence from human and experimental animals studies indicates that memory is organized into two relatively independent systems with different functions and brain mechanisms. The explicit memory system, dependent on the hippocampus and adjacent medial temporal lobe structures, refers to conscious knowledge acquisition and intentional recollection of previous experiences. The implicit memory system, dependent on the striatum, refers to learning of complex information without awareness or intention. The functioning of implicit memory can be observed in progressive, gradual improvement across many trials in performance on implicit learning tasks. The influence of explicit memory on implicit memory has not been precisely identified yet. According to data from some studies, explicit memory seems to exhibit no influence on implicit memory,whereas the other studies indicate that explicit memory may inhibit or facilitate implicit memory. The analysis of performance on implicit learning tasks in patients with different severity of explicit memory impairment due to Alzheimer's disease allows one to identify the potential influence of the explicit memory system on the implicit memory system. 51 patients with explicit memory impairment due to Alzheimer's disease (AD) and 36 healthy controls were tested. Explicit memory was examined by means of a battery of neuropsychological tests. Implicit habit learning was examined on probabilistic classification task (weather prediction task). Patients with moderate explicit memory impairment performed the implicit task significantly better than those with mild AD and controls. Results of our study support the hypothesis of competition between the implicit and explicit memory systems in humans.

  7. Prospective memory, working memory, retrospective memory and self-rated memory performance in persons with intellectual disability

    OpenAIRE

    Levén, Anna; Lyxell, Björn; Andersson, Jan; Danielsson, Henrik; Rönnberg, Jerker

    2008-01-01

    The purpose of the present study was to examine the relationship between prospective memory, working memory, retrospective memory and self-rated memory capacity in adults with and without intellectual disability. Prospective memory was investigated by means of a picture-based task. Working memory was measured as performance on span tasks. Retrospective memory was scored as recall of subject performed tasks. Self-ratings of memory performance were based on the prospective and retrospective mem...

  8. Main Memory DBMS

    NARCIS (Netherlands)

    P.A. Boncz (Peter); L. Liu (Lei); M. Tamer Özsu

    2008-01-01

    htmlabstractA main memory database system is a DBMS that primarily relies on main memory for computer data storage. In contrast, normal database management systems employ hard disk based persisntent storage.

  9. Coping with Memory Loss

    Science.gov (United States)

    ... Consumers Home For Consumers Consumer Updates Coping With Memory Loss Share Tweet Linkedin Pin it More sharing ... be evaluated by a health professional. What Causes Memory Loss? Anything that affects cognition—the process of ...

  10. Memory and Aging

    Science.gov (United States)

    Memory and Aging Losing keys, misplacing a wallet, or forgetting someone’s name are common experiences. But for people nearing or over age 65, such memory lapses can be frightening. They wonder if they ...

  11. Tracing Cultural Memory

    DEFF Research Database (Denmark)

    Wiegand, Frauke Katharina

    by their encounters – to address a question that thirty years of ground - breaking research into memory has not yet sufficiently answered: What can we learn about the dynamics of cultural memory by examining mundane accounts of touristic encounters with sites of memory? From Blaavand Beach in Western Denmark......We encounter, relate to and make use of our past and that of others in multifarious and increasingly mobile ways. Tourism is one of the main paths for encountering sites of memory. This thesis examines tourists’ creative appropriations of sites of memory – the objects and future memories inspired...... of memory. They highlight the role of mundane uses of the past and indicate the need for cross - disciplinary research on the visual and on memory...

  12. Generic Database Cost Models for Hierarchical Memory Systems

    OpenAIRE

    Manegold, Stefan; Boncz, Peter; Kersten, Martin

    2002-01-01

    textabstractAccurate prediction of operator execution time is a prerequisite for database query optimization. Although extensively studied for conventional disk-based DBMSs, cost modeling in main-memory DBMSs is still an open issue. Recent database research has demonstrated that memory access is more and more becoming a significant---if not the major---cost component of database operations. If used properly, fast but small cache memories---usually organized in cascading hierarchy between CPU ...

  13. Emotional Memory Persists Longer than Event Memory

    Science.gov (United States)

    Kuriyama, Kenichi; Soshi, Takahiro; Fujii, Takeshi; Kim, Yoshiharu

    2010-01-01

    The interaction between amygdala-driven and hippocampus-driven activities is expected to explain why emotion enhances episodic memory recognition. However, overwhelming behavioral evidence regarding the emotion-induced enhancement of immediate and delayed episodic memory recognition has not been obtained in humans. We found that the recognition…

  14. Simulated and measured performance of a real-time processor for RFI detection and mitigation on-board spaceborne microwave radiometers

    DEFF Research Database (Denmark)

    Skou, Niels; Kristensen, Steen Savstrup; Søbjærg, Sten Schmidl

    2017-01-01

    An RFI processor breadboard has been designed and developed for future spaceborne microwave radiometer systems. RFI detection is based on the anomalous amplitude, kurtosis, and cross-frequency algorithms. These are implemented in VHDL code in an FPGA. Thus algorithm performance can be assessed...... by proper code simulation. The breadboard has been integrated with a Ku band radiometer subjected to RFI-like signals from a laboratory generator. Simulations show that the algorithms as implemented work according to theory when subjected to pulsed sinusoidal and QPSK signals. The laboratory measurements...

  15. Music, memory and emotion

    Science.gov (United States)

    Jäncke, Lutz

    2008-01-01

    Because emotions enhance memory processes and music evokes strong emotions, music could be involved in forming memories, either about pieces of music or about episodes and information associated with particular music. A recent study in BMC Neuroscience has given new insights into the role of emotion in musical memory. PMID:18710596

  16. Attending to auditory memory.

    Science.gov (United States)

    Zimmermann, Jacqueline F; Moscovitch, Morris; Alain, Claude

    2016-06-01

    Attention to memory describes the process of attending to memory traces when the object is no longer present. It has been studied primarily for representations of visual stimuli with only few studies examining attention to sound object representations in short-term memory. Here, we review the interplay of attention and auditory memory with an emphasis on 1) attending to auditory memory in the absence of related external stimuli (i.e., reflective attention) and 2) effects of existing memory on guiding attention. Attention to auditory memory is discussed in the context of change deafness, and we argue that failures to detect changes in our auditory environments are most likely the result of a faulty comparison system of incoming and stored information. Also, objects are the primary building blocks of auditory attention, but attention can also be directed to individual features (e.g., pitch). We review short-term and long-term memory guided modulation of attention based on characteristic features, location, and/or semantic properties of auditory objects, and propose that auditory attention to memory pathways emerge after sensory memory. A neural model for auditory attention to memory is developed, which comprises two separate pathways in the parietal cortex, one involved in attention to higher-order features and the other involved in attention to sensory information. This article is part of a Special Issue entitled SI: Auditory working memory. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Saving Malta's music memory

    OpenAIRE

    Sant, Toni

    2013-01-01

    Maltese music is being lost. Along with it Malta loses its culture, way of life, and memories. Dr Toni Sant is trying to change this trend through the Malta Music Memory Project (M3P) http://www.um.edu.mt/think/saving-maltas-music-memory-2/

  18. Associative Memory Acceptors.

    Science.gov (United States)

    Card, Roger

    The properties of an associative memory are examined in this paper from the viewpoint of automata theory. A device called an associative memory acceptor is studied under real-time operation. The family "L" of languages accepted by real-time associative memory acceptors is shown to properly contain the family of languages accepted by one-tape,…

  19. Generation and Context Memory

    Science.gov (United States)

    Mulligan, Neil W.; Lozito, Jeffrey P.; Rosner, Zachary A.

    2006-01-01

    Generation enhances memory for occurrence but may not enhance other aspects of memory. The present study further delineates the negative generation effect in context memory reported in N. W. Mulligan (2004). First, the negative generation effect occurred for perceptual attributes of the target item (its color and font) but not for extratarget…

  20. Music, memory and emotion.

    Science.gov (United States)

    Jäncke, Lutz

    2008-08-08

    Because emotions enhance memory processes and music evokes strong emotions, music could be involved in forming memories, either about pieces of music or about episodes and information associated with particular music. A recent study in BMC Neuroscience has given new insights into the role of emotion in musical memory.

  1. Memory operation mechanism of fullerene-containing polymer memory

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Anri, E-mail: anakajima@hiroshima-u.ac.jp; Fujii, Daiki [Research Institute for Nanodevice and Bio Systems, Hiroshima University, 1-4-2 Kagamiyama, Higashihiroshima, Hiroshima 739-8527 (Japan)

    2015-03-09

    The memory operation mechanism in fullerene-containing nanocomposite gate insulators was investigated while varying the kind of fullerene in a polymer gate insulator. It was cleared what kind of traps and which positions in the nanocomposite the injected electrons or holes are stored in. The reason for the difference in the easiness of programming was clarified taking the role of the charging energy of an injected electron into account. The dependence of the carrier dynamics on the kind of fullerene molecule was investigated. A nonuniform distribution of injected carriers occurred after application of a large magnitude programming voltage due to the width distribution of the polystyrene barrier between adjacent fullerene molecules. Through the investigations, we demonstrated a nanocomposite gate with fullerene molecules having excellent retention characteristics and a programming capability. This will lead to the realization of practical organic memories with fullerene-containing polymer nanocomposites.

  2. Quantitative Estimation of Above Ground Crop Biomass using Ground-based, Airborne and Spaceborne Low Frequency Polarimetric Synthetic Aperture Radar

    Science.gov (United States)

    Koyama, C.; Watanabe, M.; Shimada, M.

    2016-12-01

    Estimation of crop biomass is one of the important challenges in environmental remote sensing related to agricultural as well as hydrological and meteorological applications. Usually passive optical data (photographs, spectral data) operating in the visible and near-infrared bands is used for such purposes. The virtue of optical remote sensing for yield estimation, however, is rather limited as the visible light can only provide information about the chemical characteristics of the canopy surface. Low frequency microwave signals with wavelength longer 20 cm have the potential to penetrate through the canopy and provide information about the whole vertical structure of vegetation from the top of the canopy down to the very soil surface. This phenomenon has been well known and exploited to detect targets under vegetation in the military radar application known as FOPEN (foliage penetration). With the availability of polarimetric interferometric SAR data the use PolInSAR techniques to retrieve vertical vegetation structures has become an attractive tool. However, PolInSAR is still highly experimental and suitable data is not yet widely available. In this study we focus on the use of operational dual-polarization L-band (1.27 GHz) SAR which is since the launch of Japan's Advanced Land Observing Satellite (ALOS, 2006-2011) available worldwide. Since 2014 ALOS-2 continues to deliver such kind of partial polarimetric data for the entire land surface. In addition to these spaceborne data sets we use airborne L-band SAR data acquired by the Japanese Pi-SAR-L2 as well as ultra-wideband (UWB) ground based SAR data operating in the frequency range from 1-4 GHz. By exploiting the complex dual-polarization [C2] Covariance matrix information, the scattering contributions from the canopy can be well separated from the ground reflections allowing for the establishment of semi-empirical relationships between measured radar reflectivity and the amount of fresh-weight above

  3. Holographic associative memories in document retrieval systems

    International Nuclear Information System (INIS)

    Becker, P.J.; Bolle, H.; Keller, A.; Kistner, W.; Riecke, W.D.; Wagner, U.

    1979-03-01

    The objective of this work was the implementation of a holographic memory with associative readout for a document retrieval system. Taking advantage of the favourable properties of holography - associative readout of the memory, parallel processing in the response store - may give shorter response times than sequentially organized data memories. Such a system may also operate in the interactive mode including chain associations. In order to avoid technological difficulties, the experimental setup made use of commercially available components only. As a result an improved holographic structure is proposed which uses volume holograms in photorefractive crystals as storage device. In two chapters of appendix we give a review of the state of the art of electrooptic devices for coherent optical data processing and of competing technologies (semiconductor associative memories and associative program systems). (orig.) [de

  4. Emotional Arousal and Multiple Memory Systems in the Mammalian Brain

    Directory of Open Access Journals (Sweden)

    Mark G. Packard

    2012-03-01

    Full Text Available Emotional arousal induced by stress and/or anxiety can exert complex effects on learning and memory processes in mammals. Recent studies have begun to link study of the influence of emotional arousal on memory with earlier research indicating that memory is organized in multiple systems in the brain that differ in terms of the type of memory they mediate. Specifically, these studies have examined whether emotional arousal may have a differential effect on the cognitive and stimulus-response habit memory processes subserved by the hippocampus and dorsal striatum, respectively. Evidence indicates that stress or the peripheral injection of anxiogenic drugs can bias animals and humans towards the use of striatal-dependent habit memory in dual-solution tasks in which both hippocampal and stritatal-based strategies can provide an adequate solution. A bias towards the use of habit memory can also be produced by intra-basolateral amygdala administration of anxiogenic drugs, consistent with the well documented role of efferent projections of this brain region in mediating the modulatory influence of emotional arousal on memory. In some learning situations, the bias towards the use of habit memory produced by emotional arousal appears to result from an impairing effect on hippocampus-dependent cognitive memory. Further research examining the neural mechanisms linking emotion and the relative use of multiple memory systems should prove useful in view of the potential role for maladaptive habitual behaviors in various human psychopathologies.

  5. Context-dependent decay of motor memories during skill acquisition.

    Science.gov (United States)

    Ingram, James N; Flanagan, J Randall; Wolpert, Daniel M

    2013-06-17

    Current models of motor learning posit that skill acquisition involves both the formation and decay of multiple motor memories that can be engaged in different contexts. Memory formation is assumed to be context dependent, so that errors most strongly update motor memories associated with the current context. In contrast, memory decay is assumed to be context independent, so that movement in any context leads to uniform decay across all contexts. We demonstrate that for both object manipulation and force-field adaptation, contrary to previous models, memory decay is highly context dependent. We show that the decay of memory associated with a given context is greatest for movements made in that context, with more distant contexts showing markedly reduced decay. Thus, both memory formation and decay are strongest for the current context. We propose that this apparently paradoxical organization provides a mechanism for optimizing performance. While memory decay tends to reduce force output, memory formation can correct for any errors that arise, allowing the motor system to regulate force output so as to both minimize errors and avoid unnecessary energy expenditure. The motor commands for any given context thus result from a balance between memory formation and decay, while memories for other contexts are preserved. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. ECT and memory loss.

    Science.gov (United States)

    Squire, L R

    1977-09-01

    The author reviews several studies that clarify the nature of the memory loss associated with ECT. Bilateral ECT produced greater anterograde memory loss than right unilateral ECT and more extensive retrograde amnesia than unilateral ECT. Reactivating memories just before ECT did not produce amnesia. Capacity for new learning recovered substantially by several months after ECT, but memory complaints were common in individuals who had received bilateral ECT. Other things being equal, right unilateral ECT seems preferable to bilateral ECT because the risks to memory associated with unilateral ECT are smaller.

  7. Determination of memory performance

    International Nuclear Information System (INIS)

    Gopych, P.M.

    1999-01-01

    Within the scope of testing statistical hypotheses theory a model definition and a computer method for model calculation of widely used in neuropsychology human memory performance (free recall, cued recall, and recognition probabilities), a model definition and a computer method for model calculation of intensities of cues used in experiments for testing human memory quality are proposed. Models for active and passive traces of memory and their relations are found. It was shown that autoassociative memory unit in the form of short two-layer artificial neural network with (or without) damages can be used for model description of memory performance in subjects with (or without) local brain lesions

  8. Quantum random access memory

    OpenAIRE

    Giovannetti, Vittorio; Lloyd, Seth; Maccone, Lorenzo

    2007-01-01

    A random access memory (RAM) uses n bits to randomly address N=2^n distinct memory cells. A quantum random access memory (qRAM) uses n qubits to address any quantum superposition of N memory cells. We present an architecture that exponentially reduces the requirements for a memory call: O(log N) switches need be thrown instead of the N used in conventional (classical or quantum) RAM designs. This yields a more robust qRAM algorithm, as it in general requires entanglement among exponentially l...

  9. Function of memory in librarians

    Directory of Open Access Journals (Sweden)

    Simona Senica

    1999-01-01

    Full Text Available The article deals with different types of memory (semantic, episodic and schematicused in a reference process by a librarian. Three types of memory are described in the same way as librarians organize information during a reference interview. Some examples are added.The second part of the article describes problems of information process encountered by students of 3rd an 4th year of librarianship during a week of their work in the library.Methodology and its characteristics, the results and their interpretation are presented.Answers of the students of 4th year indicated equal proportions of semantic and semantic-schematic type while the students of 3rd year demonstrated 72 % of semantic and 28 % of semantic-schematic type.

  10. Auditory memory can be object based.

    Science.gov (United States)

    Dyson, Benjamin J; Ishfaq, Feraz

    2008-04-01

    Identifying how memories are organized remains a fundamental issue in psychology. Previous work has shown that visual short-term memory is organized according to the object of origin, with participants being better at retrieving multiple pieces of information from the same object than from different objects. However, it is not yet clear whether similar memory structures are employed for other modalities, such as audition. Under analogous conditions in the auditory domain, we found that short-term memories for sound can also be organized according to object, with a same-object advantage being demonstrated for the retrieval of information in an auditory scene defined by two complex sounds overlapping in both space and time. Our results provide support for the notion of an auditory object, in addition to the continued identification of similar processing constraints across visual and auditory domains. The identification of modality-independent organizational principles of memory, such as object-based coding, suggests possible mechanisms by which the human processing system remembers multimodal experiences.

  11. Memory dynamics under stress.

    Science.gov (United States)

    Quaedflieg, Conny W E M; Schwabe, Lars

    2018-03-01

    Stressful events have a major impact on memory. They modulate memory formation in a time-dependent manner, closely linked to the temporal profile of action of major stress mediators, in particular catecholamines and glucocorticoids. Shortly after stressor onset, rapidly acting catecholamines and fast, non-genomic glucocorticoid actions direct cognitive resources to the processing and consolidation of the ongoing threat. In parallel, control of memory is biased towards rather rigid systems, promoting habitual forms of memory allowing efficient processing under stress, at the expense of "cognitive" systems supporting memory flexibility and specificity. In this review, we discuss the implications of this shift in the balance of multiple memory systems for the dynamics of the memory trace. Specifically, stress appears to hinder the incorporation of contextual details into the memory trace, to impede the integration of new information into existing knowledge structures, to impair the flexible generalisation across past experiences, and to hamper the modification of memories in light of new information. Delayed, genomic glucocorticoid actions might reverse the control of memory, thus restoring homeostasis and "cognitive" control of memory again.

  12. Detailed sensory memory, sloppy working memory

    Directory of Open Access Journals (Sweden)

    Ilja G Sligte

    2010-10-01

    Full Text Available Visual short-term memory (VSTM enables us to actively maintain information in mind for a brief period of time after stimulus disappearance. According to recent studies, VSTM consists of three stages - iconic memory, fragile VSTM, and visual working memory - with increasingly stricter capacity limits and progressively longer lifetimes. Still, the resolution (or amount of visual detail of each VSTM stage has remained unexplored and we test this in the present study. We presented people with a change detection task that measures the capacity of all three forms of VSTM, and we added an identification display after each change trial that required people to identify the pre-change object. Accurate change detection plus pre-change identification requires subjects to have a high-resolution representation of the pre-change object, whereas change detection or identification only can be based on the hunch that something has changed, without exactly knowing what was presented before. We observed that people maintained 6.1 objects in iconic memory, 4.6 objects in fragile VSTM and 2.1 objects in visual working memory. Moreover, when people detected the change, they could also identify the pre-change object on 88 percent of the iconic memory trials, on 71 percent of the fragile VSTM trials and merely on 53 percent of the visual working memory trials. This suggests that people maintain many high-resolution representations in iconic memory and fragile VSTM, but only one high-resolution object representation in visual working memory.

  13. NAND flash memory technologies

    CERN Document Server

    Aritome, Seiichi

    2016-01-01

    This book discusses basic and advanced NAND flash memory technologies, including the principle of NAND flash, memory cell technologies, multi-bits cell technologies, scaling challenges of memory cell, reliability, and 3-dimensional cell as the future technology. Chapter 1 describes the background and early history of NAND flash. The basic device structures and operations are described in Chapter 2. Next, the author discusses the memory cell technologies focused on scaling in Chapter 3, and introduces the advanced operations for multi-level cells in Chapter 4. The physical limitations for scaling are examined in Chapter 5, and Chapter 6 describes the reliability of NAND flash memory. Chapter 7 examines 3-dimensional (3D) NAND flash memory cells and discusses the pros and cons in structure, process, operations, scalability, and performance. In Chapter 8, challenges of 3D NAND flash memory are dis ussed. Finally, in Chapter 9, the author summarizes and describes the prospect of technologies and market for the fu...

  14. Working memory and organizational skills problems in ADHD.

    Science.gov (United States)

    Kofler, Michael J; Sarver, Dustin E; Harmon, Sherelle L; Moltisanti, Allison; Aduen, Paula A; Soto, Elia F; Ferretti, Nicole

    2018-01-01

    This study tested model-driven predictions regarding working memory's role in the organizational problems associated with ADHD. Children aged 8-13 (M = 10.33, SD = 1.42) with and without ADHD (N = 103; 39 girls; 73% Caucasian/Non-Hispanic) were assessed on multiple, counterbalanced working memory tasks. Parents and teachers completed norm-referenced measures of organizational problems (Children's Organizational Skills Scale; COSS). Results confirmed large magnitude working memory deficits (d = 1.24) and organizational problems in ADHD (d = 0.85). Bias-corrected, bootstrapped conditional effects models linked impaired working memory with greater parent- and teacher-reported inattention, hyperactivity/impulsivity, and organizational problems. Working memory predicted organization problems across all parent and teacher COSS subscales (R 2  = .19-.23). Approximately 38%-57% of working memory's effect on organization problems was conveyed by working memory's association with inattentive behavior. Unique effects of working memory remained significant for both parent- and teacher-reported task planning, as well as for teacher-reported memory/materials management and overall organization problems. Attention problems uniquely predicted worse organizational skills. Hyperactivity was unrelated to parent-reported organizational skills, but predicted better teacher-reported task planning. Children with ADHD exhibit multisetting, broad-based organizational impairment. These impaired organizational skills are attributable in part to performance deficits secondary to working memory dysfunction, both directly and indirectly via working memory's role in regulating attention. Impaired working memory in ADHD renders it extraordinarily difficult for these children to consistently anticipate, plan, enact, and maintain goal-directed actions. © 2017 Association for Child and Adolescent Mental Health.

  15. Olfactory memory in the old and very old: relations to episodic and semantic memory and APOE genotype.

    Science.gov (United States)

    Larsson, Maria; Hedner, Margareta; Papenberg, Goran; Seubert, Janina; Bäckman, Lars; Laukka, Erika J

    2016-02-01

    The neuroanatomical organization that underlies olfactory memory is different from that of other memory types. The present work examines olfactory memory in an elderly population-based sample (Swedish National Study on Aging and Care in Kungsholmen) aged 60-100 years (n = 2280). We used structural equation modeling to investigate whether olfactory memory in old age is best conceptualized as a distinct category, differentiated from episodic and semantic memory. Further, potential olfactory dedifferentiation and genetic associations (APOE) to olfactory function in late senescence were investigated. Results are in support of a 3-factor solution where olfactory memory, as indexed by episodic odor recognition and odor identification, is modeled separately from episodic and semantic memory for visual and verbal information. Increasing age was associated with poorer olfactory memory performance, and observed age-related deficits were further exacerbated for carriers of the APOE ε4 allele; these effects tended to be larger for olfactory memory compared to episodic and semantic memory pertaining to other sensory systems (vision, auditory). Finally, stronger correlations between olfactory and episodic memory, indicating dedifferentiation, were observed in the older age groups. Copyright © 2016 Elsevier Inc. All rights reserved.

  16. Molecular Mechanisms Underlying Formation of Long-Term Reward Memories and Extinction Memories in the Honeybee ("Apis Mellifera")

    Science.gov (United States)

    Eisenhardt, Dorothea

    2014-01-01

    The honeybee ("Apis mellifera") has long served as an invertebrate model organism for reward learning and memory research. Its capacity for learning and memory formation is rooted in the ecological need to efficiently collect nectar and pollen during summer to ensure survival of the hive during winter. Foraging bees learn to associate a…

  17. Memory in astrocytes: a hypothesis

    Directory of Open Access Journals (Sweden)

    Caudle Robert M

    2006-01-01

    Full Text Available Abstract Background Recent work has indicated an increasingly complex role for astrocytes in the central nervous system. Astrocytes are now known to exchange information with neurons at synaptic junctions and to alter the information processing capabilities of the neurons. As an extension of this trend a hypothesis was proposed that astrocytes function to store information. To explore this idea the ion channels in biological membranes were compared to models known as cellular automata. These comparisons were made to test the hypothesis that ion channels in the membranes of astrocytes form a dynamic information storage device. Results Two dimensional cellular automata were found to behave similarly to ion channels in a membrane when they function at the boundary between order and chaos. The length of time information is stored in this class of cellular automata is exponentially related to the number of units. Therefore the length of time biological ion channels store information was plotted versus the estimated number of ion channels in the tissue. This analysis indicates that there is an exponential relationship between memory and the number of ion channels. Extrapolation of this relationship to the estimated number of ion channels in the astrocytes of a human brain indicates that memory can be stored in this system for an entire life span. Interestingly, this information is not affixed to any physical structure, but is stored as an organization of the activity of the ion channels. Further analysis of two dimensional cellular automata also demonstrates that these systems have both associative and temporal memory capabilities. Conclusion It is concluded that astrocytes may serve as a dynamic information sink for neurons. The memory in the astrocytes is stored by organizing the activity of ion channels and is not associated with a physical location such as a synapse. In order for this form of memory to be of significant duration it is necessary

  18. Study of the variation of schistosomiasis risk in Lake Poyang in the People’s Republic of China using multiple space-borne sensors for monitoring and modelling

    Directory of Open Access Journals (Sweden)

    Kuo-Hsin Tseng

    2014-05-01

    Full Text Available The dynamics of the Poyang Lake in Jiangxi province, People’s Republic of China has been monitored to demonstrate the association of various variables with the distribution of schistosomiasis transmission with particular reference to the annual variation of the habitats for the Oncomelania snail, the intermediate host of Schistosoma japonicum. This was studied with multiple space-borne sensors, including the ENVISAT radar altimeter (RA-2 and MODIS/Terra radiometry data products such as the 16-day enhanced vegetation index, the 8-day sun reflectance, and the derived modified normalized difference water index. The measurements of physical properties were in good accordance with previous reports based on in situ gauge data, spectroradiometry and other optical methods, which encouraged us to build a predictive model based on reported geospatial constraints to assess the limits of potential variation of the snail habitat areas. The simulated results correspond fairly well with surveys conducted by local authorities showing a correlation coefficient of 0.82 between highpotential habitat areas and local estimates in a 9-year (2002-2010 analysis. Taken together, these data indicate that spaceborne observations and in situ measurements can be integrated and used as a first step of a monitoring system for control and analysis of the potential of schistosomiasis dissemination. Since the true range and intensity of transmission in the study region remain elusive at present, a long-term survey around the lake is warranted to build a robust, parametric model.

  19. Stochastic memory: Memory enhancement due to noise

    Science.gov (United States)

    Stotland, Alexander; di Ventra, Massimiliano

    2012-01-01

    There are certain classes of resistors, capacitors, and inductors that, when subject to a periodic input of appropriate frequency, develop hysteresis loops in their characteristic response. Here we show that the hysteresis of such memory elements can also be induced by white noise of appropriate intensity even at very low frequencies of the external driving field. We illustrate this phenomenon using a physical model of memory resistor realized by TiO2 thin films sandwiched between metallic electrodes and discuss under which conditions this effect can be observed experimentally. We also discuss its implications on existing memory systems described in the literature and the role of colored noise.

  20. Distortions in memory for visual displays

    Science.gov (United States)

    Tversky, Barbara

    1989-01-01

    Systematic errors in perception and memory present a challenge to theories of perception and memory and to applied psychologists interested in overcoming them as well. A number of systematic errors in memory for maps and graphs are reviewed, and they are accounted for by an analysis of the perceptual processing presumed to occur in comprehension of maps and graphs. Visual stimuli, like verbal stimuli, are organized in comprehension and memory. For visual stimuli, the organization is a consequence of perceptual processing, which is bottom-up or data-driven in its earlier stages, but top-down and affected by conceptual knowledge later on. Segregation of figure from ground is an early process, and figure recognition later; for both, symmetry is a rapidly detected and ecologically valid cue. Once isolated, figures are organized relative to one another and relative to a frame of reference. Both perceptual (e.g., salience) and conceptual factors (e.g., significance) seem likely to affect selection of a reference frame. Consistent with the analysis, subjects perceived and remembered curves in graphs and rivers in maps as more symmetric than they actually were. Symmetry, useful for detecting and recognizing figures, distorts map and graph figures alike. Top-down processes also seem to operate in that calling attention to the symmetry vs. asymmetry of a slightly asymmetric curve yielded memory errors in the direction of the description. Conceptual frame of reference effects were demonstrated in memory for lines embedded in graphs. In earlier work, the orientation of map figures was distorted in memory toward horizontal or vertical. In recent work, graph lines, but not map lines, were remembered as closer to an imaginary 45 deg line than they had been. Reference frames are determined by both perceptual and conceptual factors, leading to selection of the canonical axes as a reference frame in maps, but selection of the imaginary 45 deg as a reference frame in graphs.

  1. An ASIC memory buffer controller for a high speed disk system

    Science.gov (United States)

    Hodson, Robert F.; Campbell, Steve

    1993-01-01

    The need for large capacity, high speed mass memory storage devices has become increasingly evident at NASA during the past decade. High performance mass storage systems are crucial to present and future NASA systems. Spaceborne data storage system requirements have grown in response to the increasing amounts of data generated and processed by orbiting scientific experiments. Predictions indicate increases in the volume of data by orders of magnitude during the next decade. Current predictions are for storage capacities on the order of terabits (Tb), with data rates exceeding one gigabit per second (Gbps). As part of the design effort for a state of the art mass storage system, NASA Langley has designed a 144 CMOS ASIC to support high speed data transfers. This paper discusses the system architecture, ASIC design and some of the lessons learned in the development process.

  2. Working Memory From the Psychological and Neurosciences Perspectives: A Review.

    Science.gov (United States)

    Chai, Wen Jia; Abd Hamid, Aini Ismafairus; Abdullah, Jafri Malin

    2018-01-01

    Since the concept of working memory was introduced over 50 years ago, different schools of thought have offered different definitions for working memory based on the various cognitive domains that it encompasses. The general consensus regarding working memory supports the idea that working memory is extensively involved in goal-directed behaviors in which information must be retained and manipulated to ensure successful task execution. Before the emergence of other competing models, the concept of working memory was described by the multicomponent working memory model proposed by Baddeley and Hitch. In the present article, the authors provide an overview of several working memory-relevant studies in order to harmonize the findings of working memory from the neurosciences and psychological standpoints, especially after citing evidence from past studies of healthy, aging, diseased, and/or lesioned brains. In particular, the theoretical framework behind working memory, in which the related domains that are considered to play a part in different frameworks (such as memory's capacity limit and temporary storage) are presented and discussed. From the neuroscience perspective, it has been established that working memory activates the fronto-parietal brain regions, including the prefrontal, cingulate, and parietal cortices. Recent studies have subsequently implicated the roles of subcortical regions (such as the midbrain and cerebellum) in working memory. Aging also appears to have modulatory effects on working memory; age interactions with emotion, caffeine and hormones appear to affect working memory performances at the neurobiological level. Moreover, working memory deficits are apparent in older individuals, who are susceptible to cognitive deterioration. Another younger population with working memory impairment consists of those with mental, developmental, and/or neurological disorders such as major depressive disorder and others. A less coherent and organized neural

  3. The Impact of Current Goals on Autobiographical Memories

    DEFF Research Database (Denmark)

    Johannessen, Kim Berg; Berntsen, Dorthe

    This symposium presents four studies that illustrate how cultural life scripts and collective transitions brought about by historical events have a strong impact on autobiographical remembering and the organization of autobiographical memories across the life span. Further, knowledge about...

  4. Hybrid dual gate ferroelectric memory for multilevel information storage

    KAUST Repository

    Khan, Yasser; Caraveo-Frescas, Jesus Alfonso; Alshareef, Husam N.

    2015-01-01

    Here, we report hybrid organic/inorganic ferroelectric memory with multilevel information storage using transparent p-type SnO semiconductor and ferroelectric P(VDF-TrFE) polymer. The dual gate devices include a top ferroelectric field

  5. The contributions of handedness and working memory to episodic memory.

    Science.gov (United States)

    Sahu, Aparna; Christman, Stephen D; Propper, Ruth E

    2016-11-01

    Past studies have independently shown associations of working memory and degree of handedness with episodic memory retrieval. The current study takes a step ahead by examining whether handedness and working memory independently predict episodic memory. In agreement with past studies, there was an inconsistent-handed advantage for episodic memory; however, this advantage was absent for working memory tasks. Furthermore, regression analyses showed handedness, and complex working memory predicted episodic memory performance at different times. Results are discussed in light of theories of episodic memory and hemispheric interaction.

  6. Memory for speech and speech for memory.

    Science.gov (United States)

    Locke, J L; Kutz, K J

    1975-03-01

    Thirty kindergarteners, 15 who substituted /w/ for /r/ and 15 with correct articulation, received two perception tests and a memory test that included /w/ and /r/ in minimally contrastive syllables. Although both groups had nearly perfect perception of the experimenter's productions of /w/ and /r/, misarticulating subjects perceived their own tape-recorded w/r productions as /w/. In the memory task these same misarticulating subjects committed significantly more /w/-/r/ confusions in unspoken recall. The discussion considers why people subvocally rehearse; a developmental period in which children do not rehearse; ways subvocalization may aid recall, including motor and acoustic encoding; an echoic store that provides additional recall support if subjects rehearse vocally, and perception of self- and other- produced phonemes by misarticulating children-including its relevance to a motor theory of perception. Evidence is presented that speech for memory can be sufficiently impaired to cause memory disorder. Conceptions that restrict speech disorder to an impairment of communication are challenged.

  7. Psychophysiology of prospective memory.

    Science.gov (United States)

    Rothen, Nicolas; Meier, Beat

    2014-01-01

    Prospective memory involves the self-initiated retrieval of an intention upon an appropriate retrieval cue. Cue identification can be considered as an orienting reaction and may thus trigger a psychophysiological response. Here we present two experiments in which skin conductance responses (SCRs) elicited by prospective memory cues were compared to SCRs elicited by aversive stimuli to test whether a single prospective memory cue triggers a similar SCR as an aversive stimulus. In Experiment 2 we also assessed whether cue specificity had a differential influence on prospective memory performance and on SCRs. We found that detecting a single prospective memory cue is as likely to elicit a SCR as an aversive stimulus. Missed prospective memory cues also elicited SCRs. On a behavioural level, specific intentions led to better prospective memory performance. However, on a psychophysiological level specificity had no influence. More generally, the results indicate reliable SCRs for prospective memory cues and point to psychophysiological measures as valuable approach, which offers a new way to study one-off prospective memory tasks. Moreover, the findings are consistent with a theory that posits multiple prospective memory retrieval stages.

  8. Effect of the ZnS shell layer on the charge storage capabilities of organic bistable memory devices fabricated utilizing CuInS2–ZnS core–shell quantum dots embedded in a poly(methylmethacrylate) layer

    International Nuclear Information System (INIS)

    Yun, Dong Yeol; Kim, Tae Whan; Kim, Sang Wook

    2013-01-01

    The electrical characteristics of organic bistable memory devices (OBDs) fabricated utilizing CuInS 2 (CIS) core or CIS–ZnS core–shell quantum dots (QDs) embedded in a poly(methylmethacrylate) (PMMA) layer on indium–tin-oxide (ITO) coated glass substrates were investigated. X-ray photoelectron spectroscopy spectra demonstrated that the stoichiometries of the QDs embedded in a PMMA layer were CIS or CIS–ZnS QDs. Current–voltage measurements on Al/CIS or CIS–ZnS QDs embedded in PMMA layer/ITO glass devices at 300 K showed current bistabilities. The maximum ON/OFF current ratios of the OBDs with CIS or CIS–ZnS QDs were approximately 1 × 10 3 and 1 × 10 5 , respectively. The retention number of ON and OFF states was measured by 1 × 10 5 . The memory mechanisms of the OBDs with CIS or CIS–ZnS QDs are described on the basis of the experimental results. - Highlights: • Organic bistable devices utilizing nanocomposites were fabricated. • Current–voltage results on organic bistable devices showed current bistabilities. • Maximum ON/OFF current ratio of the device with core–shell quantum dots was 1 × 10 5 . • Retention number of the device with core–shell quantum dots was 1 × 10 5

  9. Why Narrating Changes Memory: A Contribution to an Integrative Model of Memory and Narrative Processes.

    Science.gov (United States)

    Smorti, Andrea; Fioretti, Chiara

    2016-06-01

    This paper aims to reflect on the relation between autobiographical memory (ME) and autobiographical narrative (NA), examining studies on the effects of narrating on the narrator and showing how studying these relations can make more comprehensible both memory's and narrating's way of working. Studies that address explicitly on ME and NA are scarce and touch this issue indirectly. Authors consider different trends of studies of ME and NA: congruency vs incongruency hypotheses on retrieving, the way of organizing memories according to gist or verbatim format and their role in organizing positive and negative emotional experiences, the social roots of ME and NA, the rules of conversation based on narrating. Analysis of investigations leads the Authors to point out three basic results of their research. Firstly, NA transforms ME because it narrativizes memories according to a narrative format. This means that memories, when are narrated, are transformed in stories (verbal language) and socialised. Secondly, the narrativization process is determined by the act of telling something within a communicative situation. Thus, relational situation of narrating act, by modifying the story, modifies also memories. The Authors propose the RE.NA.ME model (RElation, NArration, MEmory) to understand and study ME and NA. Finally, this study claims that ME and NA refer to two different types of processes having a wide area of overlapping. This is due to common social, developmental and cultural roots that make NA to include part of ME (narrative of memory) and ME to include part of NA (memory of personal events that have been narrated).

  10. Parallel effects of memory set activation and searchon timing and working memory capacity

    Directory of Open Access Journals (Sweden)

    Richard eSchweickert

    2014-07-01

    Full Text Available Accurately estimating a time interval is required in everyday activities such as driving or cooking. Estimating time is relatively easy, provided a person attends to it. But a brief shift of attention to another task usually interferes with timing. Most processes carried out concurrently with timing interfere with it. Curiously, some do not. Literature on a few processes suggests a general proposition, the Timing and Complex-Span Hypothesis: A process interferes with concurrent timing if and only if process performance is related to complex span. Complex-span is the number of items correctly recalled in order, when each item presented for study is followed by a brief activity. Literature on task switching, visual search, memory search, word generation and mental time travel supports the hypothesis. Previous work found that another process, activation of a memory set in long term memory, is not related to complex-span. If the Timing and Complex-Span Hypothesis is true, activation should not interfere with concurrent timing in dual-task conditions. We tested such activation in single-task memory search task conditions and in dual-task conditions where memory search was executed with concurrent timing. In Experiment 1, activating a memory set increased reaction time, with no significant effect on time production. In Experiment 2, set size and memory set activation were manipulated. Activation and set size had a puzzling interaction for time productions, perhaps due to difficult conditions, leading us to use a related but easier task in Experiment 3. In Experiment 3 increasing set size lengthened time production, but memory activation had no significant effect. Results here and in previous literature on the whole support the Timing and Complex-Span Hypotheses. Results also support a sequential organization of activation and search of memory. This organization predicts activation and set size have additive effects on reaction time and multiplicative

  11. Parallel effects of memory set activation and search on timing and working memory capacity.

    Science.gov (United States)

    Schweickert, Richard; Fortin, Claudette; Xi, Zhuangzhuang; Viau-Quesnel, Charles

    2014-01-01

    Accurately estimating a time interval is required in everyday activities such as driving or cooking. Estimating time is relatively easy, provided a person attends to it. But a brief shift of attention to another task usually interferes with timing. Most processes carried out concurrently with timing interfere with it. Curiously, some do not. Literature on a few processes suggests a general proposition, the Timing and Complex-Span Hypothesis: A process interferes with concurrent timing if and only if process performance is related to complex span. Complex-span is the number of items correctly recalled in order, when each item presented for study is followed by a brief activity. Literature on task switching, visual search, memory search, word generation and mental time travel supports the hypothesis. Previous work found that another process, activation of a memory set in long term memory, is not related to complex-span. If the Timing and Complex-Span Hypothesis is true, activation should not interfere with concurrent timing in dual-task conditions. We tested such activation in single-task memory search task conditions and in dual-task conditions where memory search was executed with concurrent timing. In Experiment 1, activating a memory set increased reaction time, with no significant effect on time production. In Experiment 2, set size and memory set activation were manipulated. Activation and set size had a puzzling interaction for time productions, perhaps due to difficult conditions, leading us to use a related but easier task in Experiment 3. In Experiment 3 increasing set size lengthened time production, but memory activation had no significant effect. Results here and in previous literature on the whole support the Timing and Complex-Span Hypotheses. Results also support a sequential organization of activation and search of memory. This organization predicts activation and set size have additive effects on reaction time and multiplicative effects on percent

  12. Stewardship, Learning, and Memory in Disaster Resilience

    Science.gov (United States)

    Tidball, Keith G.; Krasny, Marianne E.; Svendsen, Erika; Campbell, Lindsay; Helphand, Kenneth

    2010-01-01

    In this contribution, we propose and explore the following hypothesis: civic ecology practices, including urban community forestry, community gardening, and other self-organized forms of stewardship of green spaces in cities, are manifestations of how memories of the role of greening in healing can be instrumentalized through social learning to…

  13. Stewardship, learning, and memory in disaster resilience

    Science.gov (United States)

    Keith G. Tidball; Marianne E. Krasny; Erika Svendsen; Lindsay Campbell; Kenneth. Helphand

    2010-01-01

    In this contribution, we propose and explore the following hypothesis: civic ecology practices, including urban community forestry, community gardening, and other self-organized forms of stewardship of green spaces in cities, are manifestations of how memories of the role of greening in healing can be instrumentalized through social learning to foster social-ecological...

  14. Epigenetic Regulation of Memory Formation and Maintenance

    Science.gov (United States)

    Zovkic, Iva B.; Guzman-Karlsson, Mikael C.; Sweatt, J. David

    2013-01-01

    Understanding the cellular and molecular mechanisms underlying the formation and maintenance of memories is a central goal of the neuroscience community. It is well regarded that an organism's ability to lastingly adapt its behavior in response to a transient environmental stimulus relies on the central nervous system's capability for structural…

  15. From Augustine of Hippo’s Memory Systems to Our Modern Taxonomy in Cognitive Psychology and Neuroscience of Memory: A 16-Century Nap of Intuition before Light of Evidence

    OpenAIRE

    Cassel, Jean-Christophe; Cassel, Daniel; Manning, Lilianne

    2012-01-01

    Over the last half century, neuropsychologists, cognitive psychologists and cognitive neuroscientists interested in human memory have accumulated evidence showing that there is not one general memory function but a variety of memory systems deserving distinct (but for an organism, complementary) functional entities. The first attempts to organize memory systems within a taxonomic construct are often traced back to the French philosopher Maine de Biran (1766–1824), who, in his book f...

  16. Assessing boreal forest photosynthetic dynamics through space-borne measurements of greenness, chlorophyll fluorescence and model GPP

    Science.gov (United States)

    Walther, Sophia; Guanter, Luis; Voigt, Maximilian; Köhler, Philipp; Jung, Martin; Joiner, Joanna

    2015-04-01

    sophia.walther@gfz-potsdam.de The seasonality of photosynthesis of boreal forests is an essential driver of the terrestrial carbon, water and energy cycles. However, current carbon cycle model results only poorly represent interannual variability and predict very different magnitudes and timings of carbon fluxes between the atmosphere and the land surface (e.g. Jung et al. 2011, Richardson et al. 2012). Reflectance-based satellite measurements, which give an indication of the amount of green biomass on the Earth's surface, have so far been used as input to global carbon cycle simulations, but they have limitations as they are not directly linked to instantaneous photosynthesis. As an alternative, space-borne retrievals of sun-induced chlorophyll fluorescence (SIF) boast the potential to provide a direct indication of the seasonality of boreal forest photosynthetic activity and thus to improve carbon model performances. SIF is a small electromagnetic signal that is re-emitted from the photosystems in the chloroplasts, which results in a direct relationship to photosynthetic efficiency. In this contribution we examine the seasonality of the boreal forests with three different vegetation parameters, namely greenness, SIF and model simulations of gross primary production (gross carbon flux into the plants by photosynthesis, GPP). We use the enhanced vegetation index (EVI) to represent green biomass. EVI is calculated from NBAR MODIS reflectance measurements (0.05deg, 16 days temporal resolution) for the time from January 2007-May 2013. SIF data originate from GOME-2 measurements on board the MetOp-A satellite in a spatial resolution of 0.5deg for the time from 2007-2011 (Joiner et al. (2013), Köhler et al. (2014)). As a third data source, data-driven GPP model results are used for the time from 2006-2012 with 0.5deg spatial resolution. The method to quantify phenology developed by Gonsamo et al. (2013) is applied to infer the main phenological phases (greenup/onset of

  17. Intentionally fabricated autobiographical memories.

    Science.gov (United States)

    Justice, Lucy V; Morrison, Catriona M; Conway, Martin A

    2018-02-01

    Participants generated both autobiographical memories (AMs) that they believed to be true and intentionally fabricated autobiographical memories (IFAMs). Memories were constructed while a concurrent memory load (random 8-digit sequence) was held in mind or while there was no concurrent load. Amount and accuracy of recall of the concurrent memory load was reliably poorer following generation of IFAMs than following generation of AMs. There was no reliable effect of load on memory generation times; however, IFAMs always took longer to construct than AMs. Finally, replicating previous findings, fewer IFAMs had a field perspective than AMs, IFAMs were less vivid than AMs, and IFAMs contained more motion words (indicative of increased cognitive load). Taken together, these findings show a pattern of systematic differences that mark out IFAMs, and they also show that IFAMs can be identified indirectly by lowered performance on concurrent tasks that increase cognitive load.

  18. Shape memory polymers

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Thomas S.; Bearinger, Jane P.

    2017-08-29

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  19. Time for memory

    DEFF Research Database (Denmark)

    Murakami, Kyoko

    2012-01-01

    This article is a continuous dialogue on memory triggered by Brockmeier’s (2010) article. I drift away from the conventionalization of the archive as a spatial metaphor for memory in order to consider the greater possibility of “time” for conceptualizing memory. The concept of time is central...... in terms of autobiographical memory. The second category of time is discussed, drawing on Augustine and Bergson amongst others. Bergson’s notion of duration has been considered as a promising concept for a better understanding of autobiographical memory. Psychological phenomena such as autobiographical...... memory should embrace not only spatial dimension, but also a temporal dimension, in which a constant flow of irreversible time, where multiplicity, momentarily, dynamic stability and becoming and emergence of novelty can be observed....

  20. Shape memory polymers

    Science.gov (United States)

    Wilson, Thomas S.; Bearinger, Jane P.

    2015-06-09

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxyl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  1. Zone memories and pseudorandom addressing

    International Nuclear Information System (INIS)

    Marino, D.; Mirizzi, N.; Stella, R.; Visaggio, G.

    1975-01-01

    A quantitative comparison between zone memories, pseudorandom addressed memories and an alternative special purpose memory (spread zone memory) in which the distance between any two transformed descriptors, at first adjacent, is independent of the descriptors pair and results the maximum one is presented. This memory has not been particularly considered at present in spite of its efficiency and its simple implementation

  2. The Sensory Neocortex and Associative Memory.

    Science.gov (United States)

    Aschauer, Dominik; Rumpel, Simon

    2018-01-01

    Most behaviors in mammals are directly or indirectly guided by prior experience and therefore depend on the ability of our brains to form memories. The ability to form an association between an initially possibly neutral sensory stimulus and its behavioral relevance is essential for our ability to navigate in a changing environment. The formation of a memory is a complex process involving many areas of the brain. In this chapter we review classic and recent work that has shed light on the specific contribution of sensory cortical areas to the formation of associative memories. We discuss synaptic and circuit mechanisms that mediate plastic adaptations of functional properties in individual neurons as well as larger neuronal populations forming topographically organized representations. Furthermore, we describe commonly used behavioral paradigms that are used to study the mechanisms of memory formation. We focus on the auditory modality that is receiving increasing attention for the study of associative memory in rodent model systems. We argue that sensory cortical areas may play an important role for the memory-dependent categorical recognition of previously encountered sensory stimuli.

  3. Working Memory From the Psychological and Neurosciences Perspectives: A Review

    Science.gov (United States)

    Chai, Wen Jia; Abd Hamid, Aini Ismafairus; Abdullah, Jafri Malin

    2018-01-01

    Since the concept of working memory was introduced over 50 years ago, different schools of thought have offered different definitions for working memory based on the various cognitive domains that it encompasses. The general consensus regarding working memory supports the idea that working memory is extensively involved in goal-directed behaviors in which information must be retained and manipulated to ensure successful task execution. Before the emergence of other competing models, the concept of working memory was described by the multicomponent working memory model proposed by Baddeley and Hitch. In the present article, the authors provide an overview of several working memory-relevant studies in order to harmonize the findings of working memory from the neurosciences and psychological standpoints, especially after citing evidence from past studies of healthy, aging, diseased, and/or lesioned brains. In particular, the theoretical framework behind working memory, in which the related domains that are considered to play a part in different frameworks (such as memory’s capacity limit and temporary storage) are presented and discussed. From the neuroscience perspective, it has been established that working memory activates the fronto-parietal brain regions, including the prefrontal, cingulate, and parietal cortices. Recent studies have subsequently implicated the roles of subcortical regions (such as the midbrain and cerebellum) in working memory. Aging also appears to have modulatory effects on working memory; age interactions with emotion, caffeine and hormones appear to affect working memory performances at the neurobiological level. Moreover, working memory deficits are apparent in older individuals, who are susceptible to cognitive deterioration. Another younger population with working memory impairment consists of those with mental, developmental, and/or neurological disorders such as major depressive disorder and others. A less coherent and organized

  4. Working Memory From the Psychological and Neurosciences Perspectives: A Review

    Directory of Open Access Journals (Sweden)

    Wen Jia Chai

    2018-03-01

    and organized neural pattern has been consistently reported in these disadvantaged groups. Working memory of patients with traumatic brain injury was similarly affected and shown to have unusual neural activity (hyper- or hypoactivation as a general observation. Decoding the underlying neural mechanisms of working memory helps support the current theoretical understandings concerning working memory, and at the same time provides insights into rehabilitation programs that target working memory impairments from neurophysiological or psychological aspects.

  5. Music, memory and emotion

    OpenAIRE

    J?ncke, Lutz

    2008-01-01

    Because emotions enhance memory processes and music evokes strong emotions, music could be involved in forming memories, either about pieces of music or about episodes and information associated with particular music. A recent study in BMC Neuroscience has given new insights into the role of emotion in musical memory. Music has a prominent role in the everyday life of many people. Whether it is for recreation, distraction or mood enhancement, a lot of people listen to music from early in t...

  6. Making Memories Matter

    OpenAIRE

    Gold, Paul E.; Korol, Donna L.

    2012-01-01

    This article reviews some of the neuroendocrine bases by which emotional events regulate brain mechanisms of learning and memory. In laboratory rodents, there is extensive evidence that epinephrine influences memory processing through an inverted-U relationship, at which moderate levels enhance and high levels impair memory. These effects are, in large part, mediated by increases in blood glucose levels subsequent to epinephrine release, which then provide support for the brain processes en...

  7. Islamic Myths and Memories

    DEFF Research Database (Denmark)

    Islamic myths and collective memory are very much alive in today’s localized struggles for identity, and are deployed in the ongoing construction of worldwide cultural networks. This book brings the theoretical perspectives of myth-making and collective memory to the study of Islam and globalizat....... It shows how contemporary Islamic thinkers and movements respond to the challenges of globalization by preserving, reviving, reshaping, or transforming myths and memories....

  8. Iconic memory requires attention

    OpenAIRE

    Persuh, Marjan; Genzer, Boris; Melara, Robert D.

    2012-01-01

    Two experiments investigated whether attention plays a role in iconic memory, employing either a change detection paradigm (Experiment 1) or a partial-report paradigm (Experiment 2). In each experiment, attention was taxed during initial display presentation, focusing the manipulation on consolidation of information into iconic memory, prior to transfer into working memory. Observers were able to maintain high levels of performance (accuracy of change detection or categorization) even when co...

  9. Phase change memory

    CERN Document Server

    Qureshi, Moinuddin K

    2011-01-01

    As conventional memory technologies such as DRAM and Flash run into scaling challenges, architects and system designers are forced to look at alternative technologies for building future computer systems. This synthesis lecture begins by listing the requirements for a next generation memory technology and briefly surveys the landscape of novel non-volatile memories. Among these, Phase Change Memory (PCM) is emerging as a leading contender, and the authors discuss the material, device, and circuit advances underlying this exciting technology. The lecture then describes architectural solutions t

  10. Memories Persist in Silence

    Directory of Open Access Journals (Sweden)

    Sandra Patricia Arenas Grisales

    2012-08-01

    Full Text Available This article exposes the hypothesis that memory artifacts, created to commemorate the victims of armed conflict in Colombia, are an expression of the underground memories and a way of political action in the midst of war. We analyze three cases of creations of memory artifacts in Medellín, Colombia, as forms of suffering, perceiving and resisting the power of armed groups in Medellín. The silence, inherent in these objects, should not be treated as an absence of language, but as another form of expression of memory. Silence is a tactic used to overcome losses and reset everyday life in contexts of protracted violence.

  11. The future of memory

    Science.gov (United States)

    Marinella, M.

    In the not too distant future, the traditional memory and storage hierarchy of may be replaced by a single Storage Class Memory (SCM) device integrated on or near the logic processor. Traditional magnetic hard drives, NAND flash, DRAM, and higher level caches (L2 and up) will be replaced with a single high performance memory device. The Storage Class Memory paradigm will require high speed (read/write), excellent endurance (> 1012), nonvolatility (retention > 10 years), and low switching energies (memory (PCM). All of these devices show potential well beyond that of current flash technologies and research efforts are underway to improve the endurance, write speeds, and scalabilities to be on-par with DRAM. This progress has interesting implications for space electronics: each of these emerging device technologies show excellent resistance to the types of radiation typically found in space applications. Commercially developed, high density storage class memory-based systems may include a memory that is physically radiation hard, and suitable for space applications without major shielding efforts. This paper reviews the Storage Class Memory concept, emerging memory devices, and possible applicability to radiation hardened electronics for space.

  12. Sparse distributed memory overview

    Science.gov (United States)

    Raugh, Mike

    1990-01-01

    The Sparse Distributed Memory (SDM) project is investigating the theory and applications of massively parallel computing architecture, called sparse distributed memory, that will support the storage and retrieval of sensory and motor patterns characteristic of autonomous systems. The immediate objectives of the project are centered in studies of the memory itself and in the use of the memory to solve problems in speech, vision, and robotics. Investigation of methods for encoding sensory data is an important part of the research. Examples of NASA missions that may benefit from this work are Space Station, planetary rovers, and solar exploration. Sparse distributed memory offers promising technology for systems that must learn through experience and be capable of adapting to new circumstances, and for operating any large complex system requiring automatic monitoring and control. Sparse distributed memory is a massively parallel architecture motivated by efforts to understand how the human brain works. Sparse distributed memory is an associative memory, able to retrieve information from cues that only partially match patterns stored in the memory. It is able to store long temporal sequences derived from the behavior of a complex system, such as progressive records of the system's sensory data and correlated records of the system's motor controls.

  13. Models of Working Memory

    National Research Council Canada - National Science Library

    Miyake, Akira

    1997-01-01

    .... Understanding the mechanisms and structures underlying working memory is, hence, one of the most important scientific issues that need to be addressed to improve the efficiency and performance...

  14. Single-item memory, associative memory, and the human hippocampus

    OpenAIRE

    Gold, Jeffrey J.; Hopkins, Ramona O.; Squire, Larry R.

    2006-01-01

    We tested recognition memory for items and associations in memory-impaired patients with bilateral lesions thought to be limited to the hippocampal region. In Experiment 1 (Combined memory test), participants studied words and then took a memory test in which studied words, new words, studied word pairs, and recombined word pairs were presented in a mixed order. In Experiment 2 (Separated memory test), participants studied single words and then took a memory test involving studied word and ne...

  15. Memory reconsolidation mediates the updating of hippocampal memory content

    OpenAIRE

    Jonathan L C Lee

    2010-01-01

    The retrieval or reactivation of a memory places it into a labile state, requiring a process of reconsolidation to restabilize it. This retrieval-induced plasticity is a potential mechanism for the modification of the existing memory. Following previous data supportive of a functional role for memory reconsolidation in the modification of memory strength, here I show that hippocampal memory reconsolidation also supports the updating of contextual memory content. Using a procedure that se...

  16. A real-time multichannel memory controller and optimal mapping of memory clients to memory channels

    NARCIS (Netherlands)

    Gomony, M.D.; Akesson, K.B.; Goossens, K.G.W.

    2015-01-01

    Ever-increasing demands for main memory bandwidth and memory speed/power tradeoff led to the introduction of memories with multiple memory channels, such as Wide IO DRAM. Efficient utilization of a multichannel memory as a shared resource in multiprocessor real-time systems depends on mapping of the

  17. Acoustic Masking in Primary Memory

    Science.gov (United States)

    Colle, Herbert A.; Welsh, Alan

    1976-01-01

    Two experiments are reported to investigate the theory that since auditory sensory memory is used to store memory information, concurrent auditory stimulation should destroy memory information and thus reduce recall performance. (Author/RM)

  18. Memristic Characteristics from Bistable to Tristable Memory with Controllable Charge Trap Carbon Nanotubes.

    Science.gov (United States)

    Li, Lei; Wen, Dianzhong

    2018-02-17

    The incorporation of the one-dimensional carbon nanomaterial carbon nanotubes (CNTs) in poly(methyl methacrylate) (PMMA) was found to successfully develop a resistive switching. It implements memristic characteristics which shift from bistable to tristable memory. The localized current pathways in the organic nanocomposite layers for each intermediate resistive state (IRS) are attributed to the trapping mechanism consistent with the fluorescent measurements. Multi-bit organic memories have attracted considerable interest, which provide an effective way to increase the memory density per unit cell area. This study will be useful for the development and tuning of multi-bit storable organic nanocomposite memory device systems.

  19. Memristic Characteristics from Bistable to Tristable Memory with Controllable Charge Trap Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Lei Li

    2018-02-01

    Full Text Available The incorporation of the one-dimensional carbon nanomaterial carbon nanotubes (CNTs in poly(methyl methacrylate (PMMA was found to successfully develop a resistive switching. It implements memristic characteristics which shift from bistable to tristable memory. The localized current pathways in the organic nanocomposite layers for each intermediate resistive state (IRS are attributed to the trapping mechanism consistent with the fluorescent measurements. Multi-bit organic memories have attracted considerable interest, which provide an effective way to increase the memory density per unit cell area. This study will be useful for the development and tuning of multi-bit storable organic nanocomposite memory device systems.

  20. Classic and contemporary perspectives on memory

    OpenAIRE

    Bentosela, Mariana; ustel, Nadia J; Ruetti, Eliana

    2009-01-01

    Humans organize past events as “memories”, i.e. what we learn is encoded and stored in the brain, and by accumulating relevant environmental information we better cope with similar situations in the future. The main research on memory began in the 70s and the most important conclusions have been derived, on the one hand, from animal experiments, and on the other hand, from clinical studies of amnesic patients. Many classification systems of memory have been proposed. First, authors have disti...

  1. Applications for Packetized Memory Interfaces

    OpenAIRE

    Watson, Myles Glen

    2015-01-01

    The performance of the memory subsystem has a large impact on the performance of modern computer systems. Many important applications are memory bound and others are expected to become memory bound in the future. The importance of memory performance makes it imperative to understand and optimize the interactions between applications and the system architecture. Prototyping and exploring various configurations of memory systems can give important insights, but current memory interfaces are lim...

  2. Time Series with Long Memory

    OpenAIRE

    西埜, 晴久

    2004-01-01

    The paper investigates an application of long-memory processes to economic time series. We show properties of long-memory processes, which are motivated to model a long-memory phenomenon in economic time series. An FARIMA model is described as an example of long-memory model in statistical terms. The paper explains basic limit theorems and estimation methods for long-memory processes in order to apply long-memory models to economic time series.

  3. Spaceborne synthetic aperture radar: Current status and future directions. A report to the Committee on Earth Sciences, Space Studies Board, National Research Council

    Science.gov (United States)

    Evans, D. L. (Editor); Apel, J.; Arvidson, R.; Bindschadler, R.; Carsey, F.; Dozier, J.; Jezek, K.; Kasischke, E.; Li, F.; Melack, J.

    1995-01-01

    This report provides a context in which questions put forth by NASA's Office of Mission to Planet Earth (OMPTE) regarding the next steps in spaceborne synthetic aperture radar (SAR) science and technology can be addressed. It summarizes the state-of-the-art in theory, experimental design, technology, data analysis, and utilization of SAR data for studies of the Earth, and describes potential new applications. The report is divided into five science chapters and a technology assessment. The chapters summarize the value of existing SAR data and currently planned SAR systems, and identify gaps in observational capabilities needing to be filled to address the scientific questions. Cases where SAR provides complementary data to other (non-SAR) measurement techniques are also described. The chapter on technology assessment outlines SAR technology development which is critical not only to NASA's providing societally relevant geophysical parameters but to maintaining competitiveness in SAR technology, and promoting economic development.

  4. Hydrothermal alteration maps of the central and southern Basin and Range province of the United States compiled from Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data

    Science.gov (United States)

    Mars, John L.

    2013-01-01

    Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data and Interactive Data Language (IDL) logical operator algorithms were used to map hydrothermally altered rocks in the central and southern parts of the Basin and Range province of the United States. The hydrothermally altered rocks mapped in this study include (1) hydrothermal silica-rich rocks (hydrous quartz, chalcedony, opal, and amorphous silica), (2) propylitic rocks (calcite-dolomite and epidote-chlorite mapped as separate mineral groups), (3) argillic rocks (alunite-pyrophyllite-kaolinite), and (4) phyllic rocks (sericite-muscovite). A series of hydrothermal alteration maps, which identify the potential locations of hydrothermal silica-rich, propylitic, argillic, and phyllic rocks on Landsat Thematic Mapper (TM) band 7 orthorectified images, and geographic information systems shape files of hydrothermal alteration units are provided in this study.

  5. Transistor memory devices with large memory windows, using multi-stacking of densely packed, hydrophobic charge trapping metal nanoparticle array

    International Nuclear Information System (INIS)

    Cho, Ikjun; Cho, Jinhan; Kim, Beom Joon; Cho, Jeong Ho; Ryu, Sook Won

    2014-01-01

    Organic field-effect transistor (OFET) memories have rapidly evolved from low-cost and flexible electronics with relatively low-memory capacities to memory devices that require high-capacity memory such as smart memory cards or solid-state hard drives. Here, we report the high-capacity OFET memories based on the multilayer stacking of densely packed hydrophobic metal NP layers in place of the traditional transistor memory systems based on a single charge trapping layer. We demonstrated that the memory performances of devices could be significantly enhanced by controlling the adsorption isotherm behavior, multilayer stacking structure and hydrophobicity of the metal NPs. For this study, tetraoctylammonium (TOA)-stabilized Au nanoparticles (TOA-Au NPs ) were consecutively layer-by-layer (LbL) assembled with an amine-functionalized poly(amidoamine) dendrimer (PAD). The formed (PAD/TOA-Au NP ) n films were used as a multilayer stacked charge trapping layer at the interface between the tunneling dielectric layer and the SiO 2 gate dielectric layer. For a single Au NP layer (i.e. PAD/TOA-Au NP ) 1 ) with a number density of 1.82 × 10 12 cm −2 , the memory window of the OFET memory device was measured to be approximately 97 V. The multilayer stacked OFET memory devices prepared with four Au NP layers exhibited excellent programmable memory properties (i.e. a large memory window (ΔV th ) exceeding 145 V, a fast switching speed (1 μs), a high program/erase (P/E) current ratio (greater than 10 6 ) and good electrical reliability) during writing and erasing over a relatively short time scale under an operation voltage of 100 V applied at the gate. (paper)

  6. Memory systems interaction in the pigeon: working and reference memory.

    Science.gov (United States)

    Roberts, William A; Strang, Caroline; Macpherson, Krista

    2015-04-01

    Pigeons' performance on a working memory task, symbolic delayed matching-to-sample, was used to examine the interaction between working memory and reference memory. Reference memory was established by training pigeons to discriminate between the comparison cues used in delayed matching as S+ and S- stimuli. Delayed matching retention tests then measured accuracy when working and reference memory were congruent and incongruent. In 4 experiments, it was shown that the interaction between working and reference memory is reciprocal: Strengthening either type of memory leads to a decrease in the influence of the other type of memory. A process dissociation procedure analysis of the data from Experiment 4 showed independence of working and reference memory, and a model of working memory and reference memory interaction was shown to predict the findings reported in the 4 experiments. (PsycINFO Database Record (c) 2015 APA, all rights reserved).

  7. Quantification of Greenhouse Gas Emission Rates from strong Point Sources by Space-borne IPDA Lidar Measurements: Results from a Sensitivity Analysis Study

    Science.gov (United States)

    Ehret, G.; Kiemle, C.; Rapp, M.

    2017-12-01

    The practical implementation of the Paris Agreement (COP21) vastly profit from an independent, reliable and global measurement system of greenhouse gas emissions, in particular of CO2, in order to complement and cross-check national efforts. Most fossil-fuel CO2 emitters emanate from large sources such as cities and power plants. These emissions increase the local CO2 abundance in the atmosphere by 1-10 parts per million (ppm) which is a signal that is significantly larger than the variability from natural sources and sinks over the local source domain. Despite these large signals, they are only sparsely sampled by the ground-based network which calls for satellite measurements. However, none of the existing and forthcoming passive satellite instruments, operating in the NIR spectral domain, can measure CO2 emissions at night time or in low sunlight conditions and in high latitude regions in winter times. The resulting sparse coverage of passive spectrometers is a serious limitation, particularly for the Northern Hemisphere, since these regions exhibit substantial emissions during the winter as well as other times of the year. In contrast, CO2 measurements by an Integrated Path Differential Absorption (IPDA) Lidar are largely immune to these limitations and initial results from airborne application look promising. In this study, we discuss the implication for a space-borne IPDA Lidar system. A Gaussian plume model will be used to simulate the CO2-distribution of large power plants downstream to the source. The space-borne measurements are simulated by applying a simple forward model based on Gaussian error distribution. Besides the sampling frequency, the sampling geometry (e.g. measurement distance to the emitting source) and the error of the measurement itself vastly impact on the flux inversion performance. We will discuss the results by incorporating Gaussian plume and mass budget approaches to quantify the emission rates.

  8. Human Learning and Memory

    Science.gov (United States)

    Lieberman, David A.

    2012-01-01

    This innovative textbook is the first to integrate learning and memory, behaviour, and cognition. It focuses on fascinating human research in both memory and learning (while also bringing in important animal studies) and brings the reader up to date with the latest developments in the subject. Students are encouraged to think critically: key…

  9. Memory and technology

    Directory of Open Access Journals (Sweden)

    Olimpia Niglio

    2017-12-01

    Full Text Available The concept of "memory" has different meanings when analyzed within specific cultural contexts. In general, the memory expresses the ability of man to keep track of events, information, sensations, ideas, experiences, and recall this consciousness as soon as certain motivations make necessary the contribution of past experience.

  10. Shape memory alloys

    International Nuclear Information System (INIS)

    Kaszuwara, W.

    2004-01-01

    Shape memory alloys (SMA), when deformed, have the ability of returning, in certain circumstances, to their initial shape. Deformations related to this phenomenon are for polycrystals 1-8% and up to 15% for monocrystals. The deformation energy is in the range of 10 6 - 10 7 J/m 3 . The deformation is caused by martensitic transformation in the material. Shape memory alloys exhibit one directional or two directional shape memory effect as well as pseudoelastic effect. Shape change is activated by temperature change, which limits working frequency of SMA to 10 2 Hz. Other group of alloys exhibit magnetic shape memory effect. In these alloys martensitic transformation is triggered by magnetic field, thus their working frequency can be higher. Composites containing shape memory alloys can also be used as shape memory materials (applied in vibration damping devices). Another group of composite materials is called heterostructures, in which SMA alloys are incorporated in a form of thin layers The heterostructures can be used as microactuators in microelectromechanical systems (MEMS). Basic SMA comprise: Ni-Ti, Cu (Cu-Zn,Cu-Al, Cu-Sn) and Fe (Fe-Mn, Fe-Cr-Ni) alloys. Shape memory alloys find applications in such areas: automatics, safety and medical devices and many domestic appliances. Currently the most important appears to be research on magnetic shape memory materials and high temperature SMA. Vital from application point of view are composite materials especially those containing several intelligent materials. (author)

  11. Human memory search

    NARCIS (Netherlands)

    Davelaar, E.J.; Raaijmakers, J.G.W.; Hills, T.T.; Robbins, T.W.; Todd, P.M.

    2012-01-01

    The importance of understanding human memory search is hard to exaggerate: we build and live our lives based on what whe remember. This chapter explores the characteristics of memory search, with special emphasis on the use of retrieval cues. We introduce the dependent measures that are obtained

  12. Static memory devices

    NARCIS (Netherlands)

    2012-01-01

    A semiconductor memory device includes n-wells (22) and p-wells (24) used to make up a plurality of memory cell elements (40). The n-wells (22) and p-5 wells (24) can be back-biased to improve reading and writing performance. One of the n-wells and p-wells can be globally biased while the other one

  13. Human Memory: The Basics

    Science.gov (United States)

    Martinez, Michael E.

    2010-01-01

    The human mind has two types of memory: short-term and long-term. In all types of learning, it is best to use that structure rather than to fight against it. One way to do that is to ensure that learners can fit new information into patterns that can be stored in and more easily retrieved from long-term memory.

  14. Working Memory and Attitudes

    Science.gov (United States)

    Jung, Eun Sook; Reid, Norman

    2009-01-01

    Working memory capacity has been shown to be an important factor in controlling understanding in the sciences. Attitudes related to studies in the sciences are also known to be important in relation to success in learning. It might be argued that if working memory capacity is a rate controlling feature of learning and success in understanding…

  15. Reading and Working Memory

    Science.gov (United States)

    Baddeley, Alan

    1984-01-01

    Outlines the concept of working memory, with particular reference to a hypothetical subcomponent, the articulatory loop. Discusses the role of the loop in fluent adult reading, then examines the reading performance of adults with deficits in auditory verbal memory, showing that a capacity to articulate is not necessary for the effective…

  16. The memory of volatility

    Directory of Open Access Journals (Sweden)

    Kai R. Wenger

    2018-03-01

    Full Text Available The focus of the volatility literature on forecasting and the predominance of theconceptually simpler HAR model over long memory stochastic volatility models has led to the factthat the actual degree of memory estimates has rarely been considered. Estimates in the literaturerange roughly between 0.4 and 0.6 - that is from the higher stationary to the lower non-stationaryregion. This difference, however, has important practical implications - such as the existence or nonexistenceof the fourth moment of the return distribution. Inference on the memory order is complicatedby the presence of measurement error in realized volatility and the potential of spurious long memory.In this paper we provide a comprehensive analysis of the memory in variances of international stockindices and exchange rates. On the one hand, we find that the variance of exchange rates is subject tospurious long memory and the true memory parameter is in the higher stationary range. Stock indexvariances, on the other hand, are free of low frequency contaminations and the memory is in the lowernon-stationary range. These results are obtained using state of the art local Whittle methods that allowconsistent estimation in presence of perturbations or low frequency contaminations.

  17. Predicting Reasoning from Memory

    Science.gov (United States)

    Heit, Evan; Hayes, Brett K.

    2011-01-01

    In an effort to assess the relations between reasoning and memory, in 8 experiments, the authors examined how well responses on an inductive reasoning task are predicted from responses on a recognition memory task for the same picture stimuli. Across several experimental manipulations, such as varying study time, presentation frequency, and the…

  18. An Exceptional Memory

    Science.gov (United States)

    Hunter, Ian M. L.

    1977-01-01

    An account is given of the exceptional memory of the late Professor A. C. Aitken who was also a distinguished mathematician and mental calculator. Compared with Shereshevskii, another man with exceptional memory, he shows the scholar's reliance on conceptual mapping rather than the mnemonist's reliance on perceptual chaining. (Editor)

  19. Eavesdropping without quantum memory

    International Nuclear Information System (INIS)

    Bechmann-Pasquinucci, H.

    2006-01-01

    In quantum cryptography the optimal eavesdropping strategy requires that the eavesdropper uses ancillas and quantum memories in order to optimize her information. What happens if the eavesdropper has no quantum memory? It is shown that in this case the eavesdropper obtains a better information/disturbance trade-off by adopting the simple intercept/resend strategy

  20. Search of associative memory.

    NARCIS (Netherlands)

    Raaijmakers, J.G.W.; Shiffrin, R.M.

    1981-01-01

    Describes search of associative memory (SAM), a general theory of retrieval from long-term memory that combines features of associative network models and random search models. It posits cue-dependent probabilistic sampling and recovery from an associative network, but the network is specified as a

  1. The Use of Memory.

    Science.gov (United States)

    Smith, R. D.

    1983-01-01

    The predominantly linguistic orientation to current educational thinking, with its emphasis on the abstract and indirect, does not solve the problem of achieving a sense of identity. Experiential memory is crucial in personal identity. The definition and use of experiential memory and its merit are explored. (SR)

  2. Self-organizing representations

    Energy Technology Data Exchange (ETDEWEB)

    Kohonen, T.

    1983-01-01

    A property which is commonplace in the brain but which has always been ignored in learning machines is the spatial order of the processing units. This order is clearly highly significant and in nature it develops gradually during the lifetime of the organism. It then serves as the basis for perceptual and cognitive processes, and memory, too. The spatial order in biological organisms is often believed to be genetically determined. It is therefore intriguing to learn that a meaningful and optimal spatial order is formed in an extremely simple self-organizing process whereby certain feature maps are formed automatically. 8 references.

  3. Programming Robots with Associative Memories

    International Nuclear Information System (INIS)

    Touzet, C.

    1999-01-01

    Today, there are several drawbacks that impede the necessary and much needed use of robot learning techniques in real applications. First, the time needed to achieve the synthesis of any behavior is prohibitive. Second, the robot behavior during the learning phase is by definition bad, it may even be dangerous. Third, except within the lazy learning approach, a new behavior implies a new learning phase. We propose in this paper to use self-organizing maps to encode the non explicit model of the robot-world interaction sampled by the lazy memory, and then generate a robot behavior by means of situations to be achieved, i.e., points on the self-organizing maps. Any behavior can instantaneously be synthesized by the definition of a goal situation. Its performance will be minimal (not evidently bad) and will improve by the mere repetition of the behavior

  4. Programming Robots with Associative Memories

    Energy Technology Data Exchange (ETDEWEB)

    Touzet, C

    1999-07-10

    Today, there are several drawbacks that impede the necessary and much needed use of robot learning techniques in real applications. First, the time needed to achieve the synthesis of any behavior is prohibitive. Second, the robot behavior during the learning phase is "by definition" bad, it may even be dangerous. Third, except within the lazy learning approach, a new behavior implies a new learning phase. We propose in this paper to use self-organizing maps to encode the non explicit model of the robot-world interaction sampled by the lazy memory, and then generate a robot behavior by means of situations to be achieved, i.e., points on the self-organizing maps. Any behavior can instantaneously be synthesized by the definition of a goal situation. Its performance will be minimal (not evidently bad) and will improve by the mere repetition of the behavior.

  5. From Augustine of Hippo’s Memory Systems to Our Modern Taxonomy in Cognitive Psychology and Neuroscience of Memory: A 16-Century Nap of Intuition before Light of Evidence

    Directory of Open Access Journals (Sweden)

    Jean-Christophe Cassel

    2012-12-01

    Full Text Available Over the last half century, neuropsychologists, cognitive psychologists and cognitive neuroscientists interested in human memory have accumulated evidence showing that there is not one general memory function but a variety of memory systems deserving distinct (but for an organism, complementary functional entities. The first attempts to organize memory systems within a taxonomic construct are often traced back to the French philosopher Maine de Biran (1766–1824, who, in his book first published in 1803, distinguished mechanical memory, sensitive memory and representative memory, without, however, providing any experimental evidence in support of his view. It turns out, however, that what might be regarded as the first elaborated taxonomic proposal is 14 centuries older and is due to Augustine of Hippo (354–430, also named St Augustine, who, in Book 10 of his Confessions, by means of an introspective process that did not aim at organizing memory systems, nevertheless distinguished and commented on sensible memory, intellectual memory, memory of memories, memory of feelings and passion, and memory of forgetting. These memories were envisaged as different and complementary instances. In the current study, after a short biographical synopsis of St Augustine, we provide an outline of the philosopher’s contribution, both in terms of questions and answers, and focus on how this contribution almost perfectly fits with several viewpoints of modern psychology and neuroscience of memory about human memory functions, including the notion that episodic autobiographical memory stores events of our personal history in their what, where and when dimensions, and from there enables our mental time travel. It is not at all meant that St Augustine’s elaboration was the basis for the modern taxonomy, but just that the similarity is striking, and that the architecture of our current viewpoints about memory systems might have preexisted as an outstanding

  6. Working Memory in the Service of Executive Control Functions.

    Science.gov (United States)

    Mansouri, Farshad A; Rosa, Marcello G P; Atapour, Nafiseh

    2015-01-01

    Working memory is a type of short-term memory which has a crucial cognitive function that supports ongoing and upcoming behaviors, allowing storage of information across delay periods. The content of this memory may typically include tangible information about features such as the shape, color or texture of an object, and its location and motion relative to the body, as well as phonological information. The neural correlate of working memory has been found in different brain areas that are involved in organizing perceptual or motor functions. In particular, neuronal activity in prefrontal areas encodes task-related information corresponding to working memory across delay periods, and lesions in the prefrontal cortex severely affect the ability to retain this type of memory. Recent studies have further expanded the scope and possible role of working memory by showing that information of a more abstract nature (including a behavior-guiding rule, or the occurrence of a conflict in information processing) can also be maintained in short-term memory, and used for adjusting the allocation of executive control in dynamic environments. It has also been shown that neuronal activity in the prefrontal cortex encodes and maintains information about such abstract entities. These findings suggest that the prefrontal cortex plays crucial roles in the organization of goal-directed behavior by supporting many different mnemonic processes, which maintain a wide range of information required for the executive control of ongoing and upcoming behaviors.

  7. Schemas and memory consolidation.

    Science.gov (United States)

    Tse, Dorothy; Langston, Rosamund F; Kakeyama, Masaki; Bethus, Ingrid; Spooner, Patrick A; Wood, Emma R; Witter, Menno P; Morris, Richard G M

    2007-04-06

    Memory encoding occurs rapidly, but the consolidation of memory in the neocortex has long been held to be a more gradual process. We now report, however, that systems consolidation can occur extremely quickly if an associative "schema" into which new information is incorporated has previously been created. In experiments using a hippocampal-dependent paired-associate task for rats, the memory of flavor-place associations became persistent over time as a putative neocortical schema gradually developed. New traces, trained for only one trial, then became assimilated and rapidly hippocampal-independent. Schemas also played a causal role in the creation of lasting associative memory representations during one-trial learning. The concept of neocortical schemas may unite psychological accounts of knowledge structures with neurobiological theories of systems memory consolidation.

  8. Conflict and memory

    DEFF Research Database (Denmark)

    Wagoner, Brady; Brescó, Ignacio

    2016-01-01

    This introduction to the special issue on conflict and memory aims to underscore the importance of memory (whether individual and collective) in relation to intergroup conflicts. We argue that the way in which societies reconstruct and bring the past into the present—especially, the historical past......—is crucial when it comes to the study of intergroup conflict dynamics. In this regard, we also highlight the growing importance of memory studies within the area of social sciences as well as the multiple ways of approaching memory. Drawing from this wide theoretical framework, we introduce the articles...... of this issue, eight articles that tackle the role of memory in different conflicts, whether currently under way, in progress of being resolved, in postwar settings, or in contexts conflicts expected to happen do not arise....

  9. Children's episodic memory.

    Science.gov (United States)

    Ghetti, Simona; Lee, Joshua

    2011-07-01

    Episodic memory develops during childhood and adolescence. This trajectory depends on several underlying processes. In this article, we first discuss the development of the basic binding processes (e.g., the processes by which elements are bound together to form a memory episode) and control processes (e.g., reasoning and metamemory processes) involved in episodic remembering. Then, we discuss the role of these processes in false-memory formation. In the subsequent sections, we examine the neural substrates of the development of episodic memory. Finally, we discuss atypical development of episodic memory. As we proceed through the article, we suggest potential avenues for future research. WIREs Cogni Sci 2011 2 365-373 DOI: 10.1002/wcs.114 For further resources related to this article, please visit the WIREs website. Copyright © 2010 John Wiley & Sons, Ltd.

  10. Making memories matter

    Directory of Open Access Journals (Sweden)

    Paul E. Gold

    2012-12-01

    Full Text Available This article reviews some of the neuroendocrine bases by which emotional events regulate brain mechanisms of learning and memory. In laboratory rodents, there is extensive evidence that epinephrine influences memory processing through an inverted-U relationship, at which moderate levels enhance and high levels impair memory. These effects are, in large part, mediated by increases in blood glucose levels subsequent to epinephrine release, which then provide support for the brain processes engaged by learning and memory. These brain processes include augmentation of neurotransmitter release and of energy metabolism, the latter apparently including a key role for astrocytic glycogen. In addition to up- and down-regulation of learning and memory in general, physiological concomitants of emotion and arousal can also switch the neural system that controls learning at a particular time, at once improving some attributes of learning and impairing others in a manner that results in a change in the strategy used to solve a problem.

  11. Making Memories Matter

    Science.gov (United States)

    Gold, Paul E.; Korol, Donna L.

    2012-01-01

    This article reviews some of the neuroendocrine bases by which emotional events regulate brain mechanisms of learning and memory. In laboratory rodents, there is extensive evidence that epinephrine influences memory processing through an inverted-U relationship, at which moderate levels enhance and high levels impair memory. These effects are, in large part, mediated by increases in blood glucose levels subsequent to epinephrine release, which then provide support for the brain processes engaged by learning and memory. These brain processes include augmentation of neurotransmitter release and of energy metabolism, the latter apparently including a key role for astrocytic glycogen. In addition to up- and down-regulation of learning and memory in general, physiological concomitants of emotion and arousal can also switch the neural system that controls learning at a particular time, at once improving some attributes of learning and impairing others in a manner that results in a change in the strategy used to solve a problem. PMID:23264764

  12. Learning and memory.

    Science.gov (United States)

    Brem, Anna-Katharine; Ran, Kathy; Pascual-Leone, Alvaro

    2013-01-01

    Learning and memory functions are crucial in the interaction of an individual with the environment and involve the interplay of large, distributed brain networks. Recent advances in technologies to explore neurobiological correlates of neuropsychological paradigms have increased our knowledge about human learning and memory. In this chapter we first review and define memory and learning processes from a neuropsychological perspective. Then we provide some illustrations of how noninvasive brain stimulation can play a major role in the investigation of memory functions, as it can be used to identify cause-effect relationships and chronometric properties of neural processes underlying cognitive steps. In clinical medicine, transcranial magnetic stimulation may be used as a diagnostic tool to understand memory and learning deficits in various patient populations. Furthermore, noninvasive brain stimulation is also being applied to enhance cognitive functions, offering exciting translational therapeutic opportunities in neurology and psychiatry. © 2013 Elsevier B.V. All rights reserved.

  13. Optical quantum memory

    Science.gov (United States)

    Lvovsky, Alexander I.; Sanders, Barry C.; Tittel, Wolfgang

    2009-12-01

    Quantum memory is essential for the development of many devices in quantum information processing, including a synchronization tool that matches various processes within a quantum computer, an identity quantum gate that leaves any state unchanged, and a mechanism to convert heralded photons to on-demand photons. In addition to quantum computing, quantum memory will be instrumental for implementing long-distance quantum communication using quantum repeaters. The importance of this basic quantum gate is exemplified by the multitude of optical quantum memory mechanisms being studied, such as optical delay lines, cavities and electromagnetically induced transparency, as well as schemes that rely on photon echoes and the off-resonant Faraday interaction. Here, we report on state-of-the-art developments in the field of optical quantum memory, establish criteria for successful quantum memory and detail current performance levels.

  14. Validation of Atmosphere/Ionosphere Signals Associated with Major Earthquakes by Multi-Instrument Space-Borne and Ground Observations

    Science.gov (United States)

    Ouzounov, Dimitar; Pulinets, Sergey; Hattori, Katsumi; Parrot, Michel; Liu, J. Y.; Yang, T. F.; Arellano-Baeza, Alonso; Kafatos, M.; Taylor, Patrick

    2012-01-01

    ) eahquakes. Results have revealed the presence of related variations of these parameters implying their connection with the earthquake process. The second phase (B) of this validation included 102 major earthquakes (M>5.9) in Taiwan and Japan. We have found anomalous behavior before all of these events with no false negatives. False alarm ratio for false positives is less then 10% and has been calculated for the same month of the earthquake occurrence for the entire period of analysis (2003-2009). The commonalities for detecting atmospheric/ionospheric anomalies are: i.) Regularly appearance over regions of maximum stress (i.e., along plate boundaries); ii.) Anomaly existence over land and sea; and iii) association with M>5.9 earthquakes not deeper than 100km. Due to their long duration over the same region these anomalies are not consistent with a meteorological origin. Our initial results from the ISTF validation of multi-instrument space-borne and ground observations show a systematic appearance of atmospheric anomalies near the epicentral area, one to seven (average) days prior to the largest earthquakes, and suggest that it could be explained by a coupling process between the observed physical parameters and the pre-earthquake preparation processes.

  15. Task Context and Organization in Free Recall

    Science.gov (United States)

    Polyn, Sean M.; Norman, Kenneth A.; Kahana, Michael J.

    2009-01-01

    Prior work on organization in free recall has focused on the ways in which semantic and temporal information determine the order in which material is retrieved from memory. Tulving's theory of ecphory suggests that these organizational effects arise from the interaction of a retrieval cue with the contents of memory. Using the…

  16. Emerging non-volatile memories

    CERN Document Server

    Hong, Seungbum; Wouters, Dirk

    2014-01-01

    This book is an introduction to the fundamentals of emerging non-volatile memories and provides an overview of future trends in the field. Readers will find coverage of seven important memory technologies, including Ferroelectric Random Access Memory (FeRAM), Ferromagnetic RAM (FMRAM), Multiferroic RAM (MFRAM), Phase-Change Memories (PCM), Oxide-based Resistive RAM (RRAM), Probe Storage, and Polymer Memories. Chapters are structured to reflect diffusions and clashes between different topics. Emerging Non-Volatile Memories is an ideal book for graduate students, faculty, and professionals working in the area of non-volatile memory. This book also: Covers key memory technologies, including Ferroelectric Random Access Memory (FeRAM), Ferromagnetic RAM (FMRAM), and Multiferroic RAM (MFRAM), among others. Provides an overview of non-volatile memory fundamentals. Broadens readers' understanding of future trends in non-volatile memories.

  17. Phase-II Associative Memory ASIC Specifications

    CERN Document Server

    Stabile, Alberto; Warren, Matthew; Green, Barry; Konstantinidis, Nikolaos; Motuk, Halil Erdem; Frontini, Luca; Liberali, Valentino; Crescioli, Francesco; Fedi, Giacomo; Sotiropoulou, Calliope-louisa; De Canio, Francesco; Traversi, Gianluca; Shojaii, Seyed Ruhollah; Kubota, Takashi; Calderini, Giovanni; Palla, Fabrizio; Checcucci, Bruno; Spiller, Laurence Anthony; Mcnamara, Peter Charles

    2018-01-01

    This documents defines the specifications for the Associative Memory ASIC for Phase-II. The work-flow toward the final ASIC is organized in the following three steps • AM08 prototype: small area MPW prototype to test all the full custom features, the VHDL logic and the I/O. This chip must be fully functional with smaller memory area than the final ASIC; • AM09pre pre-production: full area ASIC to be fabricated with a full-mask set pilot run. Production corner wafers will be created; • AM09 production: full area ASIC with refinements for the mass production. The AM09 will be developed built on the AM08 extending the memory area, therefore the specification of both versions must be compatible.

  18. Aging Memories: Differential Decay of Episodic Memory Components

    Science.gov (United States)

    Talamini, Lucia M.; Gorree, Eva

    2012-01-01

    Some memories about events can persist for decades, even a lifetime. However, recent memories incorporate rich sensory information, including knowledge on the spatial and temporal ordering of event features, while old memories typically lack this "filmic" quality. We suggest that this apparent change in the nature of memories may reflect a…

  19. Associative working memory and subsequent episodic memory in Alzheimer's disease.

    NARCIS (Netherlands)

    Geldorp, B. van; Konings, E.P.; Tilborg, I.A. Van; Kessels, R.P.C.

    2012-01-01

    Recent studies indicate deficits in associative working memory in patients with medial-temporal lobe amnesia. However, it is unclear whether these deficits reflect working memory processing or are due to hippocampally mediated long-term memory impairment. We investigated associative working memory

  20. Associative working memory and subsequent episodic memory in Alzheimer's disease

    NARCIS (Netherlands)

    Geldorp, B. van; Konings, E.P.C.; Tilborg, I.A.D.A. van; Kessels, R.P.C.

    2012-01-01

    Recent studies indicate deficits in associative working memory in patients with medial-temporal lobe amnesia. However, it is unclear whether these deficits reflect working memory processing or are due to hippocampally mediated long-term memory impairment. We investigated associative working memory