Coherent optical memory with high storage efficiency and large fractional delay.

PubMed

Chen, Yi-Hsin; Lee, Meng-Jung; Wang, I-Chung; Du, Shengwang; Chen, Yong-Fan; Chen, Ying-Cheng; Yu, Ite A

2013-02-22

A high-storage efficiency and long-lived quantum memory for photons is an essential component in long-distance quantum communication and optical quantum computation. Here, we report a 78% storage efficiency of light pulses in a cold atomic medium based on the effect of electromagnetically induced transparency. At 50% storage efficiency, we obtain a fractional delay of 74, which is the best up-to-date record. The classical fidelity of the recalled pulse is better than 90% and nearly independent of the storage time, as confirmed by the direct measurement of phase evolution of the output light pulse with a beat-note interferometer. Such excellent phase coherence between the stored and recalled light pulses suggests that the current result may be readily applied to single photon wave packets. Our work significantly advances the technology of electromagnetically induced transparency-based optical memory and may find practical applications in long-distance quantum communication and optical quantum computation.

Electronic device aspects of neural network memories

NASA Technical Reports Server (NTRS)

Lambe, J.; Moopenn, A.; Thakoor, A. P.

1985-01-01

The basic issues related to the electronic implementation of the neural network model (NNM) for content addressable memories are examined. A brief introduction to the principles of the NNM is followed by an analysis of the information storage of the neural network in the form of a binary connection matrix and the recall capability of such matrix memories based on a hardware simulation study. In addition, materials and device architecture issues involved in the future realization of such networks in VLSI-compatible ultrahigh-density memories are considered. A possible space application of such devices would be in the area of large-scale information storage without mechanical devices.

SODR Memory Control Buffer Control ASIC

NASA Technical Reports Server (NTRS)

Hodson, Robert F.

1994-01-01

The Spacecraft Optical Disk Recorder (SODR) is a state of the art mass storage system for future NASA missions requiring high transmission rates and a large capacity storage system. This report covers the design and development of an SODR memory buffer control applications specific integrated circuit (ASIC). The memory buffer control ASIC has two primary functions: (1) buffering data to prevent loss of data during disk access times, (2) converting data formats from a high performance parallel interface format to a small computer systems interface format. Ten 144 p in, 50 MHz CMOS ASIC's were designed, fabricated and tested to implement the memory buffer control function.

Reflections on CD-ROM: Bridging the Gap between Technology and Purpose.

ERIC Educational Resources Information Center

Saviers, Shannon Smith

1987-01-01

Provides a technological overview of CD-ROM (Compact Disc-Read Only Memory), an optically-based medium for data storage offering large storage capacity, computer-based delivery system, read-only medium, and economic mass production. CD-ROM database attributes appropriate for information delivery are also reviewed, including large database size,…

The epigenetic basis of memory formation and storage.

PubMed

Jarome, Timothy J; Thomas, Jasmyne S; Lubin, Farah D

2014-01-01

The formation of long-term memory requires a series of cellular and molecular changes that involve transcriptional regulation of gene expression. While these changes in gene transcription were initially thought to be largely regulated by the activation of transcription factors by intracellular signaling molecules, epigenetic mechanisms have emerged as an important regulator of transcriptional processes across multiple brain regions to form a memory circuit for a learned event or experience. Due to their self-perpetuating nature and ability to bidirectionally control gene expression, these epigenetic mechanisms have the potential to not only regulate initial memory formation but also modify and update memory over time. This chapter focuses on the established, but poorly understood, role for epigenetic mechanisms such as posttranslational modifications of histone proteins and DNA methylation at the different stages of memory storage. Additionally, this chapter emphasizes how these mechanisms interact to control the ideal epigenetic environment for memory formation and modification in neurons. The reader will gain insights into the limitations in our current understanding of epigenetic regulation of memory storage, especially in terms of their cell-type specificity and the lack of understanding in the interactions of various epigenetic modifiers to one another to impact gene expression changes during memory formation.

Working memory and fluid intelligence: capacity, attention control, and secondary memory retrieval.

PubMed

Unsworth, Nash; Fukuda, Keisuke; Awh, Edward; Vogel, Edward K

2014-06-01

Several theories have been put forth to explain the relation between working memory (WM) and gF. Unfortunately, no single factor has been shown to fully account for the relation between these two important constructs. In the current study we tested whether multiple factors (capacity, attention control, and secondary memory) would collectively account for the relation. A large number of participants performed multiple measures of each construct and latent variable analyses were used to examine the data. The results demonstrated that capacity, attention control, and secondary memory were uniquely related to WM storage, WM processing, and gF. Importantly, the three factors completely accounted for the relation between WM (both processing and storage) and gF. Thus, although storage and processing make independent contributions to gF, both of these contributions are accounted for by variation in capacity, attention control and secondary memory. These results are consistent with the multifaceted view of WM, suggesting that individual differences in capacity, attention control, and secondary memory jointly account for individual differences in WM and its relation with gF. Copyright © 2014 Elsevier Inc. All rights reserved.

Working Memory and Fluid Intelligence: Capacity, Attention Control, and Secondary Memory Retrieval

PubMed Central

Unsworth, Nash; Fukuda, Keisuke; Awh, Edward; Vogel, Edward K.

2015-01-01

Several theories have been put forth to explain the relation between working memory (WM) and gF. Unfortunately, no single factor has been shown to fully account for the relation between these two important constructs. In the current study we tested whether multiple factors (capacity, attention control, and secondary memory) would collectively account for the relation. A large number of participants performed multiple measures of each construct and latent variable analyses were used to examine the data. The results demonstrated that capacity, attention control, and secondary memory were uniquely related to WM storage, WM processing, and gF. Importantly, the three factors completely accounted for the relation between WM (both processing and storage) and gF. Thus, although storage and processing make independent contributions to gF, both of these contributions are accounted for by variation in capacity, attention control and secondary memory. These results are consistent with the multifaceted view of WM, suggesting that individual differences in capacity, attention control, and secondary memory jointly account for individual differences in WM and its relation with gF. PMID:24531497

Improved memory characteristics by NH3-nitrided GdO as charge storage layer for nonvolatile memory applications

NASA Astrophysics Data System (ADS)

Liu, L.; Xu, J. P.; Ji, F.; Chen, J. X.; Lai, P. T.

2012-07-01

Charge-trapping memory capacitor with nitrided gadolinium oxide (GdO) as charge storage layer (CSL) is fabricated, and the influence of post-deposition annealing in NH3 on its memory characteristics is investigated. Transmission electron microscopy, x-ray photoelectron spectroscopy, and x-ray diffraction are used to analyze the cross-section and interface quality, composition, and crystallinity of the stack gate dielectric, respectively. It is found that nitrogen incorporation can improve the memory window and achieve a good trade-off among the memory properties due to NH3-annealing-induced reasonable distribution profile of a large quantity of deep-level bulk traps created in the nitrided GdO film and reduction of shallow traps near the CSL/SiO2 interface.

Progress towards broadband Raman quantum memory in Bose-Einstein condensates

NASA Astrophysics Data System (ADS)

Saglamyurek, Erhan; Hrushevskyi, Taras; Smith, Benjamin; Leblanc, Lindsay

2017-04-01

Optical quantum memories are building blocks for quantum information technologies. Efficient and long-lived storage in combination with high-speed (broadband) operation are key features required for practical applications. While the realization has been a great challenge, Raman memory in Bose-Einstein condensates (BECs) is a promising approach, due to negligible decoherence from diffusion and collisions that leads to seconds-scale memory times, high efficiency due to large atomic density, the possibility for atom-chip integration with micro photonics, and the suitability of the far off-resonant Raman approach with storage of broadband photons (over GHz) [5]. Here we report our progress towards Raman memory in a BEC. We describe our apparatus recently built for producing BEC with 87Rb atoms, and present the observation of nearly pure BEC with 5x105 atoms at 40 nK. After showing our initial characterizations, we discuss the suitability of our system for Raman-based light storage in our BEC.

Two-dimensional signal processing using a morphological filter for holographic memory

NASA Astrophysics Data System (ADS)

Kondo, Yo; Shigaki, Yusuke; Yamamoto, Manabu

2012-03-01

Today, along with the wider use of high-speed information networks and multimedia, it is increasingly necessary to have higher-density and higher-transfer-rate storage devices. Therefore, research and development into holographic memories with three-dimensional storage areas is being carried out to realize next-generation large-capacity memories. However, in holographic memories, interference between bits, which affect the detection characteristics, occurs as a result of aberrations such as the deviation of a wavefront in an optical system. In this study, we pay particular attention to the nonlinear factors that cause bit errors, where filters with a Volterra equalizer and the morphologies are investigated as a means of signal processing.

C-MOS array design techniques: SUMC multiprocessor system study

NASA Technical Reports Server (NTRS)

Clapp, W. A.; Helbig, W. A.; Merriam, A. S.

1972-01-01

The current capabilities of LSI techniques for speed and reliability, plus the possibilities of assembling large configurations of LSI logic and storage elements, have demanded the study of multiprocessors and multiprocessing techniques, problems, and potentialities. Evaluated are three previous systems studies for a space ultrareliable modular computer multiprocessing system, and a new multiprocessing system is proposed that is flexibly configured with up to four central processors, four 1/0 processors, and 16 main memory units, plus auxiliary memory and peripheral devices. This multiprocessor system features a multilevel interrupt, qualified S/360 compatibility for ground-based generation of programs, virtual memory management of a storage hierarchy through 1/0 processors, and multiport access to multiple and shared memory units.

Compact Holographic Data Storage

NASA Technical Reports Server (NTRS)

Chao, T. H.; Reyes, G. F.; Zhou, H.

2001-01-01

NASA's future missions would require massive high-speed onboard data storage capability to Space Science missions. For Space Science, such as the Europa Lander mission, the onboard data storage requirements would be focused on maximizing the spacecraft's ability to survive fault conditions (i.e., no loss in stored science data when spacecraft enters the 'safe mode') and autonomously recover from them during NASA's long-life and deep space missions. This would require the development of non-volatile memory. In order to survive in the stringent environment during space exploration missions, onboard memory requirements would also include: (1) survive a high radiation environment (1 Mrad), (2) operate effectively and efficiently for a very long time (10 years), and (3) sustain at least a billion write cycles. Therefore, memory technologies requirements of NASA's Earth Science and Space Science missions are large capacity, non-volatility, high-transfer rate, high radiation resistance, high storage density, and high power efficiency. JPL, under current sponsorship from NASA Space Science and Earth Science Programs, is developing a high-density, nonvolatile and rad-hard Compact Holographic Data Storage (CHDS) system to enable large-capacity, high-speed, low power consumption, and read/write of data in a space environment. The entire read/write operation will be controlled with electrooptic mechanism without any moving parts. This CHDS will consist of laser diodes, photorefractive crystal, spatial light modulator, photodetector array, and I/O electronic interface. In operation, pages of information would be recorded and retrieved with random access and high-speed. The nonvolatile, rad-hard characteristics of the holographic memory will provide a revolutionary memory technology meeting the high radiation challenge facing the Europa Lander mission. Additional information is contained in the original extended abstract.

A polymer/semiconductor write-once read-many-times memory

NASA Astrophysics Data System (ADS)

Möller, Sven; Perlov, Craig; Jackson, Warren; Taussig, Carl; Forrest, Stephen R.

2003-11-01

Organic devices promise to revolutionize the extent of, and access to, electronics by providing extremely inexpensive, lightweight and capable ubiquitous components that are printed onto plastic, glass or metal foils. One key component of an electronic circuit that has thus far received surprisingly little attention is an organic electronic memory. Here we report an architecture for a write-once read-many-times (WORM) memory, based on the hybrid integration of an electrochromic polymer with a thin-film silicon diode deposited onto a flexible metal foil substrate. WORM memories are desirable for ultralow-cost permanent storage of digital images, eliminating the need for slow, bulky and expensive mechanical drives used in conventional magnetic and optical memories. Our results indicate that the hybrid organic/inorganic memory device is a reliable means for achieving rapid, large-scale archival data storage. The WORM memory pixel exploits a mechanism of current-controlled, thermally activated un-doping of a two-component electrochromic conducting polymer.

The Science of Computing: Virtual Memory

NASA Technical Reports Server (NTRS)

Denning, Peter J.

1986-01-01

In the March-April issue, I described how a computer's storage system is organized as a hierarchy consisting of cache, main memory, and secondary memory (e.g., disk). The cache and main memory form a subsystem that functions like main memory but attains speeds approaching cache. What happens if a program and its data are too large for the main memory? This is not a frivolous question. Every generation of computer users has been frustrated by insufficient memory. A new line of computers may have sufficient storage for the computations of its predecessor, but new programs will soon exhaust its capacity. In 1960, a longrange planning committee at MIT dared to dream of a computer with 1 million words of main memory. In 1985, the Cray-2 was delivered with 256 million words. Computational physicists dream of computers with 1 billion words. Computer architects have done an outstanding job of enlarging main memories yet they have never kept up with demand. Only the shortsighted believe they can.

Place Cells, Grid Cells, and Memory

PubMed Central

Moser, May-Britt; Rowland, David C.; Moser, Edvard I.

2015-01-01

The hippocampal system is critical for storage and retrieval of declarative memories, including memories for locations and events that take place at those locations. Spatial memories place high demands on capacity. Memories must be distinct to be recalled without interference and encoding must be fast. Recent studies have indicated that hippocampal networks allow for fast storage of large quantities of uncorrelated spatial information. The aim of the this article is to review and discuss some of this work, taking as a starting point the discovery of multiple functionally specialized cell types of the hippocampal–entorhinal circuit, such as place, grid, and border cells. We will show that grid cells provide the hippocampus with a metric, as well as a putative mechanism for decorrelation of representations, that the formation of environment-specific place maps depends on mechanisms for long-term plasticity in the hippocampus, and that long-term spatiotemporal memory storage may depend on offline consolidation processes related to sharp-wave ripple activity in the hippocampus. The multitude of representations generated through interactions between a variety of functionally specialized cell types in the entorhinal–hippocampal circuit may be at the heart of the mechanism for declarative memory formation. PMID:25646382

How to Use Removable Mass Storage Memory Devices

ERIC Educational Resources Information Center

Branzburg, Jeffrey

2004-01-01

Mass storage refers to the variety of ways to keep large amounts of information that are used on a computer. Over the years, the removable storage devices have grown smaller, increased in capacity, and transferred the information to the computer faster. The 8" floppy disk of the 1960s stored 100 kilobytes, or about 60 typewritten, double-spaced…

A Strategy to Design High-Density Nanoscale Devices utilizing Vapor Deposition of Metal Halide Perovskite Materials.

PubMed

Hwang, Bohee; Lee, Jang-Sik

2017-08-01

The demand for high memory density has increased due to increasing needs of information storage, such as big data processing and the Internet of Things. Organic-inorganic perovskite materials that show nonvolatile resistive switching memory properties have potential applications as the resistive switching layer for next-generation memory devices, but, for practical applications, these materials should be utilized in high-density data-storage devices. Here, nanoscale memory devices are fabricated by sequential vapor deposition of organolead halide perovskite (OHP) CH 3 NH 3 PbI 3 layers on wafers perforated with 250 nm via-holes. These devices have bipolar resistive switching properties, and show low-voltage operation, fast switching speed (200 ns), good endurance, and data-retention time >10 5 s. Moreover, the use of sequential vapor deposition is extended to deposit CH 3 NH 3 PbI 3 as the memory element in a cross-point array structure. This method to fabricate high-density memory devices could be used for memory cells that occupy large areas, and to overcome the scaling limit of existing methods; it also presents a way to use OHPs to increase memory storage capacity. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A model for the distributed storage and processing of large arrays

NASA Technical Reports Server (NTRS)

Mehrota, P.; Pratt, T. W.

1983-01-01

A conceptual model for parallel computations on large arrays is developed. The model provides a set of language concepts appropriate for processing arrays which are generally too large to fit in the primary memories of a multiprocessor system. The semantic model is used to represent arrays on a concurrent architecture in such a way that the performance realities inherent in the distributed storage and processing can be adequately represented. An implementation of the large array concept as an Ada package is also described.

Max-plus and min-plus projection autoassociative morphological memories and their compositions for pattern classification.

PubMed

Dos Santos, Alex Santana; Valle, Marcos Eduardo

2018-04-01

Autoassociative morphological memories (AMMs) are robust and computationally efficient memory models with unlimited storage capacity. In this paper, we present the max-plus and min-plus projection autoassociative morphological memories (PAMMs) as well as their compositions. Briefly, the max-plus PAMM yields the largest max-plus combination of the stored vectors which is less than or equal to the input. Dually, the vector recalled by the min-plus PAMM corresponds to the smallest min-plus combination which is larger than or equal to the input. Apart from unlimited absolute storage capacity and one step retrieval, PAMMs and their compositions exhibit an excellent noise tolerance. Furthermore, the new memories yielded quite promising results in classification problems with a large number of features and classes. Copyright © 2018 Elsevier Ltd. All rights reserved.

Computer memory power control for the Galileo spacecraft

NASA Technical Reports Server (NTRS)

Detwiler, R. C.

1983-01-01

The developmental history, major design drives, and final topology of the computer memory power system on the Galileo spacecraft are described. A unique method of generating memory backup power directly from the fault current drawn during a spacecraft power overload or fault condition allows this system to provide continuous memory power. This concept provides a unique solution to the problem of volatile memory loss without the use of a battery of other large energy storage elements usually associated with uninterrupted power supply designs.

An ASIC memory buffer controller for a high speed disk system

NASA Technical Reports Server (NTRS)

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.

Asymmetric programming: a highly reliable metadata allocation strategy for MLC NAND flash memory-based sensor systems.

PubMed

Huang, Min; Liu, Zhaoqing; Qiao, Liyan

2014-10-10

While the NAND flash memory is widely used as the storage medium in modern sensor systems, the aggressive shrinking of process geometry and an increase in the number of bits stored in each memory cell will inevitably degrade the reliability of NAND flash memory. In particular, it's critical to enhance metadata reliability, which occupies only a small portion of the storage space, but maintains the critical information of the file system and the address translations of the storage system. Metadata damage will cause the system to crash or a large amount of data to be lost. This paper presents Asymmetric Programming, a highly reliable metadata allocation strategy for MLC NAND flash memory storage systems. Our technique exploits for the first time the property of the multi-page architecture of MLC NAND flash memory to improve the reliability of metadata. The basic idea is to keep metadata in most significant bit (MSB) pages which are more reliable than least significant bit (LSB) pages. Thus, we can achieve relatively low bit error rates for metadata. Based on this idea, we propose two strategies to optimize address mapping and garbage collection. We have implemented Asymmetric Programming on a real hardware platform. The experimental results show that Asymmetric Programming can achieve a reduction in the number of page errors of up to 99.05% with the baseline error correction scheme.

Asymmetric Programming: A Highly Reliable Metadata Allocation Strategy for MLC NAND Flash Memory-Based Sensor Systems

PubMed Central

Huang, Min; Liu, Zhaoqing; Qiao, Liyan

2014-01-01

While the NAND flash memory is widely used as the storage medium in modern sensor systems, the aggressive shrinking of process geometry and an increase in the number of bits stored in each memory cell will inevitably degrade the reliability of NAND flash memory. In particular, it's critical to enhance metadata reliability, which occupies only a small portion of the storage space, but maintains the critical information of the file system and the address translations of the storage system. Metadata damage will cause the system to crash or a large amount of data to be lost. This paper presents Asymmetric Programming, a highly reliable metadata allocation strategy for MLC NAND flash memory storage systems. Our technique exploits for the first time the property of the multi-page architecture of MLC NAND flash memory to improve the reliability of metadata. The basic idea is to keep metadata in most significant bit (MSB) pages which are more reliable than least significant bit (LSB) pages. Thus, we can achieve relatively low bit error rates for metadata. Based on this idea, we propose two strategies to optimize address mapping and garbage collection. We have implemented Asymmetric Programming on a real hardware platform. The experimental results show that Asymmetric Programming can achieve a reduction in the number of page errors of up to 99.05% with the baseline error correction scheme. PMID:25310473

Sentinel 2 MMFU: The first European Mass Memory System Based on NAND-Flash Storage Technology

NASA Astrophysics Data System (ADS)

Staehle, M.; Cassel, M.; Lonsdorfer, U.; Gliem, F.; Walter, D.; Fichna, T.

2011-08-01

Sentinel-2 is the multispectral optical mission of the EU-ESA GMES (Global Monitoring for Environment and Security) program, currently under development by Astrium-GmbH in Friedrichshafen (Germany) for a launch in 2013. The mission features a 490 Mbit/s optical sensor operating at high duty cycles, requiring in turn a large 2.4 Tbit on-board storage capacity.The required storage capacity motivated the selection of the NAND-Flash technology which was already secured by a lengthy period (2004-2009) of detailed testing, analysis and qualification by Astrium GmbH, IDA and ESTEC. The mass memory system is currently being realized by Astrium GmbH.

Tunnel field-effect transistor charge-trapping memory with steep subthreshold slope and large memory window

NASA Astrophysics Data System (ADS)

Kino, Hisashi; Fukushima, Takafumi; Tanaka, Tetsu

2018-04-01

Charge-trapping memory requires the increase of bit density per cell and a larger memory window for lower-power operation. A tunnel field-effect transistor (TFET) can achieve to increase the bit density per cell owing to its steep subthreshold slope. In addition, a TFET structure has an asymmetric structure, which is promising for achieving a larger memory window. A TFET with the N-type gate shows a higher electric field between the P-type source and the N-type gate edge than the conventional FET structure. This high electric field enables large amounts of charges to be injected into the charge storage layer. In this study, we fabricated silicon-oxide-nitride-oxide-semiconductor (SONOS) memory devices with the TFET structure and observed a steep subthreshold slope and a larger memory window.

The Library and Human Memory. Final Report on Mechanized Information Services in the University Library, Phase I - Planning. Part 13.

ERIC Educational Resources Information Center

Norman, Donald A.

This paper discusses the differences between the storage problems encountered in a large library and those encountered in the human memory. Some of the properties of the human memory system and some of the major issues which affect the interaction between human users and the existing library systems are outlined. The problem of browsing is used as…

Holographic Compact Disk Read-Only Memories

NASA Technical Reports Server (NTRS)

Liu, Tsuen-Hsi

1996-01-01

Compact disk read-only memories (CD-ROMs) of proposed type store digital data in volume holograms instead of in surface differentially reflective elements. Holographic CD-ROM consist largely of parts similar to those used in conventional CD-ROMs. However, achieves 10 or more times data-storage capacity and throughput by use of wavelength-multiplexing/volume-hologram scheme.

A Compute Capable SSD Architecture for Next-Generation Non-volatile Memories

DOE Office of Scientific and Technical Information (OSTI.GOV)

De, Arup

2014-01-01

Existing storage technologies (e.g., disks and ash) are failing to cope with the processor and main memory speed and are limiting the overall perfor- mance of many large scale I/O or data-intensive applications. Emerging fast byte-addressable non-volatile memory (NVM) technologies, such as phase-change memory (PCM), spin-transfer torque memory (STTM) and memristor are very promising and are approaching DRAM-like performance with lower power con- sumption and higher density as process technology scales. These new memories are narrowing down the performance gap between the storage and the main mem- ory and are putting forward challenging problems on existing SSD architecture, I/O interfacemore » (e.g, SATA, PCIe) and software. This dissertation addresses those challenges and presents a novel SSD architecture called XSSD. XSSD o oads com- putation in storage to exploit fast NVMs and reduce the redundant data tra c across the I/O bus. XSSD o ers a exible RPC-based programming framework that developers can use for application development on SSD without dealing with the complication of the underlying architecture and communication management. We have built a prototype of XSSD on the BEE3 FPGA prototyping system. We implement various data-intensive applications and achieve speedup and energy ef- ciency of 1.5-8.9 and 1.7-10.27 respectively. This dissertation also compares XSSD with previous work on intelligent storage and intelligent memory. The existing ecosystem and these new enabling technologies make this system more viable than earlier ones.« less

Set processing in a network environment. [data bases and magnetic disks and tapes

NASA Technical Reports Server (NTRS)

Hardgrave, W. T.

1975-01-01

A combination of a local network, a mass storage system, and an autonomous set processor serving as a data/storage management machine is described. Its characteristics include: content-accessible data bases usable from all connected devices; efficient storage/access of large data bases; simple and direct programming with data manipulation and storage management handled by the set processor; simple data base design and entry from source representation to set processor representation with no predefinition necessary; capability available for user sort/order specification; significant reduction in tape/disk pack storage and mounts; flexible environment that allows upgrading hardware/software configuration without causing major interruptions in service; minimal traffic on data communications network; and improved central memory usage on large processors.

Ultra-High Density Holographic Memory Module with Solid-State Architecture

NASA Technical Reports Server (NTRS)

Markov, Vladimir B.

2000-01-01

NASA's terrestrial. space, and deep-space missions require technology that allows storing. retrieving, and processing a large volume of information. Holographic memory offers high-density data storage with parallel access and high throughput. Several methods exist for data multiplexing based on the fundamental principles of volume hologram selectivity. We recently demonstrated that a spatial (amplitude-phase) encoding of the reference wave (SERW) looks promising as a way to increase the storage density. The SERW hologram offers a method other than traditional methods of selectivity, such as spatial de-correlation between recorded and reconstruction fields, In this report we present the experimental results of the SERW-hologram memory module with solid-state architecture, which is of particular interest for space operations.

Multipulse addressing of a Raman quantum memory: configurable beam splitting and efficient readout.

PubMed

Reim, K F; Nunn, J; Jin, X-M; Michelberger, P S; Champion, T F M; England, D G; Lee, K C; Kolthammer, W S; Langford, N K; Walmsley, I A

2012-06-29

Quantum memories are vital to the scalability of photonic quantum information processing (PQIP), since the storage of photons enables repeat-until-success strategies. On the other hand, the key element of all PQIP architectures is the beam splitter, which allows us to coherently couple optical modes. Here, we show how to combine these crucial functionalities by addressing a Raman quantum memory with multiple control pulses. The result is a coherent optical storage device with an extremely large time bandwidth product, that functions as an array of dynamically configurable beam splitters, and that can be read out with arbitrarily high efficiency. Networks of such devices would allow fully scalable PQIP, with applications in quantum computation, long distance quantum communications and quantum metrology.

Radiation-Hardened Solid-State Drive

NASA Technical Reports Server (NTRS)

Sheldon, Douglas J.

2010-01-01

A method is provided for a radiationhardened (rad-hard) solid-state drive for space mission memory applications by combining rad-hard and commercial off-the-shelf (COTS) non-volatile memories (NVMs) into a hybrid architecture. The architecture is controlled by a rad-hard ASIC (application specific integrated circuit) or a FPGA (field programmable gate array). Specific error handling and data management protocols are developed for use in a rad-hard environment. The rad-hard memories are smaller in overall memory density, but are used to control and manage radiation-induced errors in the main, and much larger density, non-rad-hard COTS memory devices. Small amounts of rad-hard memory are used as error buffers and temporary caches for radiation-induced errors in the large COTS memories. The rad-hard ASIC/FPGA implements a variety of error-handling protocols to manage these radiation-induced errors. The large COTS memory is triplicated for protection, and CRC-based counters are calculated for sub-areas in each COTS NVM array. These counters are stored in the rad-hard non-volatile memory. Through monitoring, rewriting, regeneration, triplication, and long-term storage, radiation-induced errors in the large NV memory are managed. The rad-hard ASIC/FPGA also interfaces with the external computer buses.

System and method for programmable bank selection for banked memory subsystems

DOEpatents

Blumrich, Matthias A.; Chen, Dong; Gara, Alan G.; Giampapa, Mark E.; Hoenicke, Dirk; Ohmacht, Martin; Salapura, Valentina; Sugavanam, Krishnan

2010-09-07

A programmable memory system and method for enabling one or more processor devices access to shared memory in a computing environment, the shared memory including one or more memory storage structures having addressable locations for storing data. The system comprises: one or more first logic devices associated with a respective one or more processor devices, each first logic device for receiving physical memory address signals and programmable for generating a respective memory storage structure select signal upon receipt of pre-determined address bit values at selected physical memory address bit locations; and, a second logic device responsive to each of the respective select signal for generating an address signal used for selecting a memory storage structure for processor access. The system thus enables each processor device of a computing environment memory storage access distributed across the one or more memory storage structures.

Monolayer optical memory cells based on artificial trap-mediated charge storage and release

NASA Astrophysics Data System (ADS)

Lee, Juwon; Pak, Sangyeon; Lee, Young-Woo; Cho, Yuljae; Hong, John; Giraud, Paul; Shin, Hyeon Suk; Morris, Stephen M.; Sohn, Jung Inn; Cha, Seungnam; Kim, Jong Min

2017-03-01

Monolayer transition metal dichalcogenides are considered to be promising candidates for flexible and transparent optoelectronics applications due to their direct bandgap and strong light-matter interactions. Although several monolayer-based photodetectors have been demonstrated, single-layered optical memory devices suitable for high-quality image sensing have received little attention. Here we report a concept for monolayer MoS2 optoelectronic memory devices using artificially-structured charge trap layers through the functionalization of the monolayer/dielectric interfaces, leading to localized electronic states that serve as a basis for electrically-induced charge trapping and optically-mediated charge release. Our devices exhibit excellent photo-responsive memory characteristics with a large linear dynamic range of ~4,700 (73.4 dB) coupled with a low OFF-state current (<4 pA), and a long storage lifetime of over 104 s. In addition, the multi-level detection of up to 8 optical states is successfully demonstrated. These results represent a significant step toward the development of future monolayer optoelectronic memory devices.

Flash drive memory apparatus and method

NASA Technical Reports Server (NTRS)

Hinchey, Michael G. (Inventor)

2010-01-01

A memory apparatus includes a non-volatile computer memory, a USB mass storage controller connected to the non-volatile computer memory, the USB mass storage controller including a daisy chain component, a male USB interface connected to the USB mass storage controller, and at least one other interface for a memory device, other than a USB interface, the at least one other interface being connected to the USB mass storage controller.

Communication: Practical and rigorous reduction of the many-electron quantum mechanical Coulomb problem to O(N{sup 2/3}) storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pederson, Mark R., E-mail: mark.pederson@science.doe.gov

2015-04-14

It is tacitly accepted that, for practical basis sets consisting of N functions, solution of the two-electron Coulomb problem in quantum mechanics requires storage of O(N{sup 4}) integrals in the small N limit. For localized functions, in the large N limit, or for planewaves, due to closure, the storage can be reduced to O(N{sup 2}) integrals. Here, it is shown that the storage can be further reduced to O(N{sup 2/3}) for separable basis functions. A practical algorithm, that uses standard one-dimensional Gaussian-quadrature sums, is demonstrated. The resulting algorithm allows for the simultaneous storage, or fast reconstruction, of any two-electron Coulombmore » integral required for a many-electron calculation on processors with limited memory and disk space. For example, for calculations involving a basis of 9171 planewaves, the memory required to effectively store all Coulomb integrals decreases from 2.8 Gbytes to less than 2.4 Mbytes.« less

Communication: practical and rigorous reduction of the many-electron quantum mechanical Coulomb problem to O(N(2/3)) storage.

PubMed

Pederson, Mark R

2015-04-14

It is tacitly accepted that, for practical basis sets consisting of N functions, solution of the two-electron Coulomb problem in quantum mechanics requires storage of O(N(4)) integrals in the small N limit. For localized functions, in the large N limit, or for planewaves, due to closure, the storage can be reduced to O(N(2)) integrals. Here, it is shown that the storage can be further reduced to O(N(2/3)) for separable basis functions. A practical algorithm, that uses standard one-dimensional Gaussian-quadrature sums, is demonstrated. The resulting algorithm allows for the simultaneous storage, or fast reconstruction, of any two-electron Coulomb integral required for a many-electron calculation on processors with limited memory and disk space. For example, for calculations involving a basis of 9171 planewaves, the memory required to effectively store all Coulomb integrals decreases from 2.8 Gbytes to less than 2.4 Mbytes.

In search of a recognition memory engram

PubMed Central

Brown, M.W.; Banks, P.J.

2015-01-01

A large body of data from human and animal studies using psychological, recording, imaging, and lesion techniques indicates that recognition memory involves at least two separable processes: familiarity discrimination and recollection. Familiarity discrimination for individual visual stimuli seems to be effected by a system centred on the perirhinal cortex of the temporal lobe. The fundamental change that encodes prior occurrence within the perirhinal cortex is a reduction in the responses of neurones when a stimulus is repeated. Neuronal network modelling indicates that a system based on such a change in responsiveness is potentially highly efficient in information theoretic terms. A review is given of findings indicating that perirhinal cortex acts as a storage site for recognition memory of objects and that such storage depends upon processes producing synaptic weakening. PMID:25280908

ERP C250 Shows the Elderly (Cognitively Normal, Alzheimer’s Disease) Store More Stimuli in Short-Term Memory than Young Adults Do

PubMed Central

Chapman, Robert M.; Gardner, Margaret N.; Mapstone, Mark; Klorman, Rafael; Porsteinsson, Anton P.; Dupree, Haley M.; Antonsdottir, Inga M.; Kamalyan, Lily

2016-01-01

Objective To determine how aging and dementia affect the brain’s initial storing of task-relevant and irrelevant information in short-term memory. Methods We used brain Event-Related Potentials (ERPs) to measure short-term memory storage (ERP component C250) in 36 Young Adults, 36 Normal Elderly, and 36 early-stage AD subjects. Participants performed the Number-Letter task, a cognitive paradigm requiring memory storage of a first relevant stimulus to compare it with a second stimulus. Results In Young Adults, C250 was more positive for the first task-relevant stimulus compared to all other stimuli. C250 in Normal Elderly and AD subjects was roughly the same to relevant and irrelevant stimuli in intratrial parts 1–3 but not 4. The AD group had lower C250 to relevant stimuli in part 1. Conclusions Both normal aging and dementia cause less differentiation of relevant from irrelevant information in initial storage. There was a large aging effect involving differences in the pattern of C250 responses of the Young Adult versus the Normal Elderly/AD groups. Also, a potential dementia effect was obtained. Significance C250 is a candidate tool for measuring short-term memory performance on a biological level, as well as a potential marker for memory changes due to normal aging and dementia. PMID:27178862

Elaborated Resources: An Instructional Design Strategy for Hypermedia.

ERIC Educational Resources Information Center

Rezabek, Randall H.; Ragan, Tillman J.

The concept of hypertext was introduced by Ted Nelson in 1965, but only recently has the widely available technology caught up with the idea. The new generation of microcomputers featuring large internal memories, graphic interfaces, and large data storage capacities have made the commercial development of hypertext/hypermedia software possible. A…

Memory engram storage and retrieval.

PubMed

Tonegawa, Susumu; Pignatelli, Michele; Roy, Dheeraj S; Ryan, Tomás J

2015-12-01

A great deal of experimental investment is directed towards questions regarding the mechanisms of memory storage. Such studies have traditionally been restricted to investigation of the anatomical structures, physiological processes, and molecular pathways necessary for the capacity of memory storage, and have avoided the question of how individual memories are stored in the brain. Memory engram technology allows the labeling and subsequent manipulation of components of specific memory engrams in particular brain regions, and it has been established that cell ensembles labeled by this method are both sufficient and necessary for memory recall. Recent research has employed this technology to probe fundamental questions of memory consolidation, differentiating between mechanisms of memory retrieval from the true neurobiology of memory storage. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Architectural design and simulation of a virtual memory

NASA Technical Reports Server (NTRS)

Kwok, G.; Chu, Y.

1971-01-01

Virtual memory is an imaginary main memory with a very large capacity which the programmer has at his disposal. It greatly contributes to the solution of the dynamic storage allocation problem. The architectural design of a virtual memory is presented which implements by hardware the idea of queuing and scheduling the page requests to a paging drum in such a way that the access of the paging drum is increased many times. With the design, an increase of up to 16 times in page transfer rate is achievable when the virtual memory is heavily loaded. This in turn makes feasible a great increase in the system throughput.

Packaging of a large capacity magnetic bubble domain spacecraft recorder

NASA Technical Reports Server (NTRS)

Becker, F. J.; Stermer, R. L.

1977-01-01

A Solid State Spacecraft Data Recorder (SSDR), based on bubble domain technology, having a storage capacity of 10 to the 8th power bits, was designed and is being tested. The recorder consists of two memory modules each having 32 cells, each cell containing sixteen 100 kilobit serial bubble memory chips. The memory modules are interconnected to a Drive and Control Unit (DCU) module containing four microprocessors, 500 integrated circuits, a RAM core memory and two PROM's. The two memory modules and DCU are housed in individual machined aluminum frames, are stacked in brick fashion and through bolted to a base plate assembly which also houses the power supply.

Fabry-Perot confocal resonator optical associative memory

NASA Astrophysics Data System (ADS)

Burns, Thomas J.; Rogers, Steven K.; Vogel, George A.

1993-03-01

A unique optical associative memory architecture is presented that combines the optical processing environment of a Fabry-Perot confocal resonator with the dynamic storage and recall properties of volume holograms. The confocal resonator reduces the size and complexity of previous associative memory architectures by folding a large number of discrete optical components into an integrated, compact optical processing environment. Experimental results demonstrate the system is capable of recalling a complete object from memory when presented with partial information about the object. A Fourier optics model of the system's operation shows it implements a spatially continuous version of a discrete, binary Hopfield neural network associative memory.

Multimodal properties and dynamics of gradient echo quantum memory.

PubMed

Hétet, G; Longdell, J J; Sellars, M J; Lam, P K; Buchler, B C

2008-11-14

We investigate the properties of a recently proposed gradient echo memory (GEM) scheme for information mapping between optical and atomic systems. We show that GEM can be described by the dynamic formation of polaritons in k space. This picture highlights the flexibility and robustness with regards to the external control of the storage process. Our results also show that, as GEM is a frequency-encoding memory, it can accurately preserve the shape of signals that have large time-bandwidth products, even at moderate optical depths. At higher optical depths, we show that GEM is a high fidelity multimode quantum memory.

Cryptography in the Bounded-Quantum-Storage Model

NASA Astrophysics Data System (ADS)

Schaffner, Christian

2007-09-01

This thesis initiates the study of cryptographic protocols in the bounded-quantum-storage model. On the practical side, simple protocols for Rabin Oblivious Transfer, 1-2 Oblivious Transfer and Bit Commitment are presented. No quantum memory is required for honest players, whereas the protocols can only be broken by an adversary controlling a large amount of quantum memory. The protocols are efficient, non-interactive and can be implemented with today's technology. On the theoretical side, new entropic uncertainty relations involving min-entropy are established and used to prove the security of protocols according to new strong security definitions. For instance, in the realistic setting of Quantum Key Distribution (QKD) against quantum-memory-bounded eavesdroppers, the uncertainty relation allows to prove the security of QKD protocols while tolerating considerably higher error rates compared to the standard model with unbounded adversaries.

In search of a recognition memory engram.

PubMed

Brown, M W; Banks, P J

2015-03-01

A large body of data from human and animal studies using psychological, recording, imaging, and lesion techniques indicates that recognition memory involves at least two separable processes: familiarity discrimination and recollection. Familiarity discrimination for individual visual stimuli seems to be effected by a system centred on the perirhinal cortex of the temporal lobe. The fundamental change that encodes prior occurrence within the perirhinal cortex is a reduction in the responses of neurones when a stimulus is repeated. Neuronal network modelling indicates that a system based on such a change in responsiveness is potentially highly efficient in information theoretic terms. A review is given of findings indicating that perirhinal cortex acts as a storage site for recognition memory of objects and that such storage depends upon processes producing synaptic weakening. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

Verbal learning on depressive pseudodementia: accentuate impairment of free recall, moderate on learning processes, and spared short-term and recognition memory.

PubMed

Paula, Jonas Jardim de; Miranda, Débora Marques; Nicolato, Rodrigo; Moraes, Edgar Nunes de; Bicalho, Maria Aparecida Camargos; Malloy-Diniz, Leandro Fernandes

2013-09-01

Depressive pseudodementia (DPD) is a clinical condition characterized by depressive symptoms followed by cognitive and functional impairment characteristics of dementia. Memory complaints are one of the most related cognitive symptoms in DPD. The present study aims to assess the verbal learning profile of elderly patients with DPD. Ninety-six older adults (34 DPD and 62 controls) were assessed by neuropsychological tests including the Rey auditory-verbal learning test (RAVLT). A multivariate general linear model was used to assess group differences and controlled for demographic factors. Moderate or large effects were found on all RAVLT components, except for short-term and recognition memory. DPD impairs verbal memory, with large effect size on free recall and moderate effect size on the learning. Short-term storage and recognition memory are useful in clinical contexts when the differential diagnosis is required.

Phase-change materials for non-volatile memory devices: from technological challenges to materials science issues

NASA Astrophysics Data System (ADS)

Noé, Pierre; Vallée, Christophe; Hippert, Françoise; Fillot, Frédéric; Raty, Jean-Yves

2018-01-01

Chalcogenide phase-change materials (PCMs), such as Ge-Sb-Te alloys, have shown outstanding properties, which has led to their successful use for a long time in optical memories (DVDs) and, recently, in non-volatile resistive memories. The latter, known as PCM memories or phase-change random access memories (PCRAMs), are the most promising candidates among emerging non-volatile memory (NVM) technologies to replace the current FLASH memories at CMOS technology nodes under 28 nm. Chalcogenide PCMs exhibit fast and reversible phase transformations between crystalline and amorphous states with very different transport and optical properties leading to a unique set of features for PCRAMs, such as fast programming, good cyclability, high scalability, multi-level storage capability, and good data retention. Nevertheless, PCM memory technology has to overcome several challenges to definitively invade the NVM market. In this review paper, we examine the main technological challenges that PCM memory technology must face and we illustrate how new memory architecture, innovative deposition methods, and PCM composition optimization can contribute to further improvements of this technology. In particular, we examine how to lower the programming currents and increase data retention. Scaling down PCM memories for large-scale integration means the incorporation of the PCM into more and more confined structures and raises materials science issues in order to understand interface and size effects on crystallization. Other materials science issues are related to the stability and ageing of the amorphous state of PCMs. The stability of the amorphous phase, which determines data retention in memory devices, can be increased by doping the PCM. Ageing of the amorphous phase leads to a large increase of the resistivity with time (resistance drift), which has up to now hindered the development of ultra-high multi-level storage devices. A review of the current understanding of all these issues is provided from a materials science point of view.

ERP C250 shows the elderly (cognitively normal, Alzheimer's disease) store more stimuli in short-term memory than Young Adults do.

PubMed

Chapman, Robert M; Gardner, Margaret N; Mapstone, Mark; Klorman, Rafael; Porsteinsson, Anton P; Dupree, Haley M; Antonsdottir, Inga M; Kamalyan, Lily

2016-06-01

To determine how aging and dementia affect the brain's initial storing of task-relevant and irrelevant information in short-term memory. We used brain Event-Related Potentials (ERPs) to measure short-term memory storage (ERP component C250) in 36 Young Adults, 36 Normal Elderly, and 36 early-stage AD subjects. Participants performed the Number-Letter task, a cognitive paradigm requiring memory storage of a first relevant stimulus to compare it with a second stimulus. In Young Adults, C250 was more positive for the first task-relevant stimulus compared to all other stimuli. C250 in Normal Elderly and AD subjects was roughly the same to relevant and irrelevant stimuli in Intratrial Parts 1-3 but not 4. The AD group had lower C250 to relevant stimuli in part 1. Both normal aging and dementia cause less differentiation of relevant from irrelevant information in initial storage. There was a large aging effect involving differences in the pattern of C250 responses of the Young Adult versus the Normal Elderly/AD groups. Also, a potential dementia effect was obtained. C250 is a candidate tool for measuring short-term memory performance on a biological level, as well as a potential marker for memory changes due to normal aging and dementia. Copyright © 2016 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

Phase change cellular automata modeling of GeTe, GaSb and SnSe stacked chalcogenide films

NASA Astrophysics Data System (ADS)

Mihai, C.; Velea, A.

2018-06-01

Data storage needs are increasing at a rapid pace across all economic sectors, so the need for new memory technologies with adequate capabilities is also high. Phase change memories (PCMs) are a leading contender in the emerging race for non-volatile memories due to their fast operation speed, high scalability, good reliability and low power consumption. However, in order to meet the present and future storage demands, PCM technologies must further increase the storage density. Here, we employ a probabilistic cellular automata approach to explore the multi-step threshold switching from the reset (off) to the set (on) state in chalcogenide stacked structures. Simulations have shown that in order to obtain multi-step switching with high contrast among different resistance states, the stacked structure needs to contain materials with a large difference among their crystallization temperatures and careful tuning of strata thicknesses. The crystallization dynamics can be controlled through the external energy pulses applied to the system, in such a way that a balance between nucleation and growth in phase change behavior can be achieved, optimized for PCMs.

Impact of Recent Hardware and Software Trends on High Performance Transaction Processing and Analytics

NASA Astrophysics Data System (ADS)

Mohan, C.

In this paper, I survey briefly some of the recent and emerging trends in hardware and software features which impact high performance transaction processing and data analytics applications. These features include multicore processor chips, ultra large main memories, flash storage, storage class memories, database appliances, field programmable gate arrays, transactional memory, key-value stores, and cloud computing. While some applications, e.g., Web 2.0 ones, were initially built without traditional transaction processing functionality in mind, slowly system architects and designers are beginning to address such previously ignored issues. The availability, analytics and response time requirements of these applications were initially given more importance than ACID transaction semantics and resource consumption characteristics. A project at IBM Almaden is studying the implications of phase change memory on transaction processing, in the context of a key-value store. Bitemporal data management has also become an important requirement, especially for financial applications. Power consumption and heat dissipation properties are also major considerations in the emergence of modern software and hardware architectural features. Considerations relating to ease of configuration, installation, maintenance and monitoring, and improvement of total cost of ownership have resulted in database appliances becoming very popular. The MapReduce paradigm is now quite popular for large scale data analysis, in spite of the major inefficiencies associated with it.

Overview of Probe-based Storage Technologies

NASA Astrophysics Data System (ADS)

Wang, Lei; Yang, Ci Hui; Wen, Jing; Gong, Si Di; Peng, Yuan Xiu

2016-07-01

The current world is in the age of big data where the total amount of global digital data is growing up at an incredible rate. This indeed necessitates a drastic enhancement on the capacity of conventional data storage devices that are, however, suffering from their respective physical drawbacks. Under this circumstance, it is essential to aggressively explore and develop alternative promising mass storage devices, leading to the presence of probe-based storage devices. In this paper, the physical principles and the current status of several different probe storage devices, including thermo-mechanical probe memory, magnetic probe memory, ferroelectric probe memory, and phase-change probe memory, are reviewed in details, as well as their respective merits and weakness. This paper provides an overview of the emerging probe memories potentially for next generation storage device so as to motivate the exploration of more innovative technologies to push forward the development of the probe storage devices.

Overview of Probe-based Storage Technologies.

PubMed

Wang, Lei; Yang, Ci Hui; Wen, Jing; Gong, Si Di; Peng, Yuan Xiu

2016-12-01

The current world is in the age of big data where the total amount of global digital data is growing up at an incredible rate. This indeed necessitates a drastic enhancement on the capacity of conventional data storage devices that are, however, suffering from their respective physical drawbacks. Under this circumstance, it is essential to aggressively explore and develop alternative promising mass storage devices, leading to the presence of probe-based storage devices. In this paper, the physical principles and the current status of several different probe storage devices, including thermo-mechanical probe memory, magnetic probe memory, ferroelectric probe memory, and phase-change probe memory, are reviewed in details, as well as their respective merits and weakness. This paper provides an overview of the emerging probe memories potentially for next generation storage device so as to motivate the exploration of more innovative technologies to push forward the development of the probe storage devices.

Data storage technology comparisons

NASA Technical Reports Server (NTRS)

Katti, Romney R.

1990-01-01

The role of data storage and data storage technology is an integral, though conceptually often underestimated, portion of data processing technology. Data storage is important in the mass storage mode in which generated data is buffered for later use. But data storage technology is also important in the data flow mode when data are manipulated and hence required to flow between databases, datasets and processors. This latter mode is commonly associated with memory hierarchies which support computation. VLSI devices can reasonably be defined as electronic circuit devices such as channel and control electronics as well as highly integrated, solid-state devices that are fabricated using thin film deposition technology. VLSI devices in both capacities play an important role in data storage technology. In addition to random access memories (RAM), read-only memories (ROM), and other silicon-based variations such as PROM's, EPROM's, and EEPROM's, integrated devices find their way into a variety of memory technologies which offer significant performance advantages. These memory technologies include magnetic tape, magnetic disk, magneto-optic disk, and vertical Bloch line memory. In this paper, some comparison between selected technologies will be made to demonstrate why more than one memory technology exists today, based for example on access time and storage density at the active bit and system levels.

Paging memory from random access memory to backing storage in a parallel computer

DOEpatents

Archer, Charles J; Blocksome, Michael A; Inglett, Todd A; Ratterman, Joseph D; Smith, Brian E

2013-05-21

Paging memory from random access memory (`RAM`) to backing storage in a parallel computer that includes a plurality of compute nodes, including: executing a data processing application on a virtual machine operating system in a virtual machine on a first compute node; providing, by a second compute node, backing storage for the contents of RAM on the first compute node; and swapping, by the virtual machine operating system in the virtual machine on the first compute node, a page of memory from RAM on the first compute node to the backing storage on the second compute node.

A class Hierarchical, object-oriented approach to virtual memory management

NASA Technical Reports Server (NTRS)

Russo, Vincent F.; Campbell, Roy H.; Johnston, Gary M.

1989-01-01

The Choices family of operating systems exploits class hierarchies and object-oriented programming to facilitate the construction of customized operating systems for shared memory and networked multiprocessors. The software is being used in the Tapestry laboratory to study the performance of algorithms, mechanisms, and policies for parallel systems. Described here are the architectural design and class hierarchy of the Choices virtual memory management system. The software and hardware mechanisms and policies of a virtual memory system implement a memory hierarchy that exploits the trade-off between response times and storage capacities. In Choices, the notion of a memory hierarchy is captured by abstract classes. Concrete subclasses of those abstractions implement a virtual address space, segmentation, paging, physical memory management, secondary storage, and remote (that is, networked) storage. Captured in the notion of a memory hierarchy are classes that represent memory objects. These classes provide a storage mechanism that contains encapsulated data and have methods to read or write the memory object. Each of these classes provides specializations to represent the memory hierarchy.

High Cycle-life Shape Memory Polymer at High Temperature

PubMed Central

Kong, Deyan; Xiao, Xinli

2016-01-01

High cycle-life is important for shape memory materials exposed to numerous cycles, and here we report shape memory polyimide that maintained both high shape fixity (Rf) and shape recovery (Rr) during the more than 1000 bending cycles tested. Its critical stress is 2.78 MPa at 250 °C, and the shape recovery process can produce stored energy of 0.218 J g−1 at the efficiency of 31.3%. Its high Rf is determined by the large difference in storage modulus at rubbery and glassy states, while the high Rr mainly originates from its permanent phase composed of strong π-π interactions and massive chain entanglements. Both difference in storage modulus and overall permanent phase were preserved during the bending deformation cycles, and thus high Rf and Rr were observed in every cycle and the high cycle-life will expand application areas of SMPs enormously. PMID:27641148

A kilobyte rewritable atomic memory

NASA Astrophysics Data System (ADS)

Kalff, Floris; Rebergen, Marnix; Fahrenfort, Nora; Girovsky, Jan; Toskovic, Ranko; Lado, Jose; FernáNdez-Rossier, JoaquíN.; Otte, Sander

The ability to manipulate individual atoms by means of scanning tunneling microscopy (STM) opens op opportunities for storage of digital data on the atomic scale. Recent achievements in this direction include data storage based on bits encoded in the charge state, the magnetic state, or the local presence of single atoms or atomic assemblies. However, a key challenge at this stage is the extension of such technologies into large-scale rewritable bit arrays. We demonstrate a digital atomic-scale memory of up to 1 kilobyte (8000 bits) using an array of individual surface vacancies in a chlorine terminated Cu(100) surface. The chlorine vacancies are found to be stable at temperatures up to 77 K. The memory, crafted using scanning tunneling microscopy at low temperature, can be read and re-written automatically by means of atomic-scale markers, and offers an areal density of 502 Terabits per square inch, outperforming state-of-the-art hard disk drives by three orders of magnitude.

Disentangling the adult attention-deficit hyperactivity disorder endophenotype: parametric measurement of attention.

PubMed

Finke, Kathrin; Schwarzkopf, Wolfgang; Müller, Ulrich; Frodl, Thomas; Müller, Hermann J; Schneider, Werner X; Engel, Rolf R; Riedel, Michael; Möller, Hans-Jürgen; Hennig-Fast, Kristina

2011-11-01

Attention deficit hyperactivity disorder (ADHD) persists frequently into adulthood. The decomposition of endophenotypes by means of experimental neuro-cognitive assessment has the potential to improve diagnostic assessment, evaluation of treatment response, and disentanglement of genetic and environmental influences. We assessed four parameters of attentional capacity and selectivity derived from simple psychophysical tasks (verbal report of briefly presented letter displays) and based on a "theory of visual attention." These parameters are mathematically independent, quantitative measures, and previous studies have shown that they are highly sensitive for subtle attention deficits. Potential reductions of attentional capacity, that is, of perceptual processing speed and working memory storage capacity, were assessed with a whole report paradigm. Furthermore, possible pathologies of attentional selectivity, that is, selection of task-relevant information and bias in the spatial distribution of attention, were measured with a partial report paradigm. A group of 30 unmedicated adult ADHD patients and a group of 30 demographically matched healthy controls were tested. ADHD patients showed significant reductions of working memory storage capacity of a moderate to large effect size. Perceptual processing speed, task-based, and spatial selection were unaffected. The results imply a working memory deficit as an important source of behavioral impairments. The theory of visual attention parameter working memory storage capacity might constitute a quantifiable and testable endophenotype of ADHD.

The Relationship between Processing and Storage in Working Memory Span: Not Two Sides of the Same Coin

ERIC Educational Resources Information Center

Maehara, Yukio; Saito, Satoru

2007-01-01

In working memory (WM) span tests, participants maintain memory items while performing processing tasks. In this study, we examined the impact of task processing requirements on memory-storage activities, looking at the stimulus order effect and the impact of storage requirements on processing activities, testing the processing time effect in WM…

Mass storage technology in networks

NASA Astrophysics Data System (ADS)

Ishii, Katsunori; Takeda, Toru; Itao, Kiyoshi; Kaneko, Reizo

1990-08-01

Trends and features of mass storage subsystems in network are surveyed and their key technologies spotlighted. Storage subsystems are becoming increasingly important in new network systems in which communications and data processing are systematically combined. These systems require a new class of high-performance mass-information storage in order to effectively utilize their processing power. The requirements of high transfer rates, high transactional rates and large storage capacities, coupled with high functionality, fault tolerance and flexibility in configuration, are major challenges in storage subsystems. Recent progress in optical disk technology has resulted in improved performance of on-line external memories to optical disk drives, which are competing with mid-range magnetic disks. Optical disks are more effective than magnetic disks in using low-traffic random-access file storing multimedia data that requires large capacity, such as in archive use and in information distribution use by ROM disks. Finally, it demonstrates image coded document file servers for local area network use that employ 130mm rewritable magneto-optical disk subsystems.

Data Movement Dominates: Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jacob, Bruce L.

Over the past three years in this project, what we have observed is that the primary reason for data movement in large-scale systems is that the per-node capacity is not large enough—i.e., one of the solutions to the data-movement problem (certainly not the only solution that is required, but a significant one nonetheless) is to increase per-node capacity so that inter-node traffic is reduced. This unfortunately is not as simple as it sounds. Today’s main memory systems for datacenters, enterprise computing systems, and supercomputers, fail to provide high per-socket capacity [Dirik & Jacob 2009; Cooper-Balis et al. 2012], except atmore » extremely high price points (factors of 10–100x the cost/bit of consumer main-memory systems) [Stokes 2008]. The reason is that our choice of technology for today’s main memory systems—i.e., DRAM, which we have used as a main-memory technology since the 1970s [Jacob et al. 2007]—can no longer keep up with our needs for density and price per bit. Main memory systems have always been built from the cheapest, densest, lowest-power memory technology available, and DRAM is no longer the cheapest, the densest, nor the lowest-power storage technology out there. It is now time for DRAM to go the way that SRAM went: move out of the way for a cheaper, slower, denser storage technology, and become a cache instead. This inflection point has happened before, in the context of SRAM yielding to DRAM. There was once a time that SRAM was the storage technology of choice for all main memories [Tomasulo 1967; Thornton 1970; Kidder 1981]. However, once DRAM hit volume production in the 1970s and 80s, it supplanted SRAM as a main memory technology because it was cheaper, and it was denser. It also happened to be lower power, but that was not the primary consideration of the day. At the time, it was recognized that DRAM was much slower than SRAM, but it was only at the supercomputer level (For instance the Cray X-MP in the 1980s and its follow-on, the Cray Y-MP, in the 1990s) that could one afford to build ever- larger main memories out of SRAM—the reasoning for moving to DRAM was that an appropriately designed memory hierarchy, built of DRAM as main memory and SRAM as a cache, would approach the performance of SRAM, at the price-per-bit of DRAM [Mashey 1999]. Today it is quite clear that, were one to build an entire multi-gigabyte main memory out of SRAM instead of DRAM, one could improve the performance of almost any computer system by up to an order of magnitude—but this option is not even considered, because to build that system would be prohibitively expensive. It is now time to revisit the same design choice in the context of modern technologies and modern systems. For reasons both technical and economic, we can no longer afford to build ever-larger main memory systems out of DRAM. Flash memory, on the other hand, is significantly cheaper and denser than DRAM and therefore should take its place. While it is true that flash is significantly slower than DRAM, one can afford to build much larger main memories out of flash than out of DRAM, and we show that an appropriately designed memory hierarchy, built of flash as main memory and DRAM as a cache, will approach the performance of DRAM, at the price-per-bit of flash. In our studies as part of this project, we have investigated Non-Volatile Main Memory (NVMM), a new main-memory architecture for large-scale computing systems, one that is specifically designed to address the weaknesses described previously. In particular, it provides the following features: non-volatility: The bulk of the storage is comprised of NAND flash, and in this organization DRAM is used only as a cache, not as main memory. Furthermore, the flash is journaled, which means that operations such as checkpoint/restore are already built into the system. 1+ terabytes of storage per socket: SSDs and DRAM DIMMs have roughly the same form factor (several square inches of PCB surface area), and terabyte SSDs are now commonplace. performance approaching that of DRAM: DRAM is used as a cache to the flash system. price-per-bit approaching that of NAND: Flash is currently well under $0.50 per gigabyte; DDR3 SDRAM is currently just over $10 per gigabyte [Newegg 2014]. Even today, one can build an easily affordable main memory system with a terabyte or more of NAND storage per CPU socket (which would be extremely expensive were one to use DRAM), and our cycle- accurate, full-system experiments show that this can be done at a performance point that lies within a factor of two of DRAM.« less

Holographic storage of biphoton entanglement.

PubMed

Dai, Han-Ning; Zhang, Han; Yang, Sheng-Jun; Zhao, Tian-Ming; Rui, Jun; Deng, You-Jin; Li, Li; Liu, Nai-Le; Chen, Shuai; Bao, Xiao-Hui; Jin, Xian-Min; Zhao, Bo; Pan, Jian-Wei

2012-05-25

Coherent and reversible storage of multiphoton entanglement with a multimode quantum memory is essential for scalable all-optical quantum information processing. Although a single photon has been successfully stored in different quantum systems, storage of multiphoton entanglement remains challenging because of the critical requirement for coherent control of the photonic entanglement source, multimode quantum memory, and quantum interface between them. Here we demonstrate a coherent and reversible storage of biphoton Bell-type entanglement with a holographic multimode atomic-ensemble-based quantum memory. The retrieved biphoton entanglement violates the Bell inequality for 1 μs storage time and a memory-process fidelity of 98% is demonstrated by quantum state tomography.

Organization and Memory in Adulthood.

ERIC Educational Resources Information Center

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…

Benchmarking Memory Performance with the Data Cube Operator

NASA Technical Reports Server (NTRS)

Frumkin, Michael A.; Shabanov, Leonid V.

2004-01-01

Data movement across a computer memory hierarchy and across computational grids is known to be a limiting factor for applications processing large data sets. We use the Data Cube Operator on an Arithmetic Data Set, called ADC, to benchmark capabilities of computers and of computational grids to handle large distributed data sets. We present a prototype implementation of a parallel algorithm for computation of the operatol: The algorithm follows a known approach for computing views from the smallest parent. The ADC stresses all levels of grid memory and storage by producing some of 2d views of an Arithmetic Data Set of d-tuples described by a small number of integers. We control data intensity of the ADC by selecting the tuple parameters, the sizes of the views, and the number of realized views. Benchmarking results of memory performance of a number of computer architectures and of a small computational grid are presented.

A Radiation-Tolerant, Low-Power Non-Volatile Memory Based on Silicon Nanocrystal Quantum Dots

NASA Technical Reports Server (NTRS)

Bell, L. D.; Boer, E. A.; Ostraat, M. L.; Brongersma, M. L.; Flagan, R. C.; Atwater, H. A.; deBlauwe, J.; Green, M. L.

2001-01-01

Nanocrystal nonvolatile floating-gate memories are a good candidate for space applications - initial results suggest they are fast, more reliable and consume less power than conventional floating gate memories. In the nanocrystal based NVM device, charge is not stored on a continuous polysilicon layer (so-called floating gate), but instead on a layer of discrete nanocrystals. Charge injection and storage in dense arrays of silicon nanocrystals in SiO2 is a critical aspect of the performance of potential nanocrystal flash memory structures. The ultimate goal for this class of devices is few- or single-electron storage in a small number of nanocrystal elements. In addition, the nanocrystal layer fabrication technique should be simple, 8-inch wafer compatible and well controlled in program/erase threshold voltage swing was seen during 100,000 program and erase cycles. Additional near-term goals for this project include extensive testing for radiation hardness and the development of artificial layered tunnel barrier heterostructures which have the potential for large speed enhancements for read/write of nanocrystal memory elements, compared with conventional flash devices. Additional information is contained in the original extended abstract.

The future of memory

NASA Astrophysics Data System (ADS)

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 (< 100 ns read/write), excellent endurance (> 1012), nonvolatility (retention > 10 years), and low switching energies (< 10 pJ per switch). The International Technology Roadmap for Semiconductors (ITRS) has recently evaluated several potential candidates SCM technologies, including Resistive (or Redox) RAM, Spin Torque Transfer RAM (STT-MRAM), and phase change 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.

Coherent storage of temporally multimode light using a spin-wave atomic frequency comb memory

NASA Astrophysics Data System (ADS)

Gündoǧan, M.; Mazzera, M.; Ledingham, P. M.; Cristiani, M.; de Riedmatten, H.

2013-04-01

We report on the coherent and multi-temporal mode storage of light using the full atomic frequency comb memory scheme. The scheme involves the transfer of optical atomic excitations in Pr3+:Y2SiO5 to spin waves in hyperfine levels using strong single-frequency transfer pulses. Using this scheme, a total of five temporal modes are stored and recalled on-demand from the memory. The coherence of the storage and retrieval is characterized using a time-bin interference measurement resulting in visibilities higher than 80%, independent of the storage time. This coherent and multimode spin-wave memory is promising as a quantum memory for light.

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

NASA Astrophysics Data System (ADS)

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.

Brain Region-Specific Activity Patterns after Recent or Remote Memory Retrieval of Auditory Conditioned Fear

ERIC Educational Resources Information Center

Kwon, Jeong-Tae; Jhang, Jinho; Kim, Hyung-Su; Lee, Sujin; Han, Jin-Hee

2012-01-01

Memory is thought to be sparsely encoded throughout multiple brain regions forming unique memory trace. Although evidence has established that the amygdala is a key brain site for memory storage and retrieval of auditory conditioned fear memory, it remains elusive whether the auditory brain regions may be involved in fear memory storage or…

The past, the future and the biology of memory storage.

PubMed Central

Kandel, E R; Pittenger, C

1999-01-01

We here briefly review a century of accomplishments in studying memory storage and delineate the two major questions that have dominated thinking in this area: the systems question of memory, which concerns where in the brain storage occurs; and the molecular question of memory, which concerns the mechanisms whereby memories are stored and maintained. We go on to consider the themes that memory research may be able to address in the 21st century. Finally, we reflect on the clinical and societal import of our increasing understanding of the mechanisms of memory, discussing possible therapeutic approaches to diseases that manifest with disruptions of learning and possible ethical implication of the ability, which is on the horizon, to ameliorate or even enhance human memory. PMID:10670023

Device and methods for writing and erasing analog information in small memory units via voltage pulses

DOEpatents

El Gabaly Marquez, Farid; Talin, Albert Alec

2018-04-17

Devices and methods for non-volatile analog data storage are described herein. In an exemplary embodiment, an analog memory device comprises a potential-carrier source layer, a barrier layer deposited on the source layer, and at least two storage layers deposited on the barrier layer. The memory device can be prepared to write and read data via application of a biasing voltage between the source layer and the storage layers, wherein the biasing voltage causes potential-carriers to migrate into the storage layers. After initialization, data can be written to the memory device by application of a voltage pulse between two storage layers that causes potential-carriers to migrate from one storage layer to another. A difference in concentration of potential carriers caused by migration of potential-carriers between the storage layers results in a voltage that can be measured in order to read the written data.

Associative Memory Synthesis, Performance, Storage Capacity And Updating: New Heteroassociative Memory Results

NASA Astrophysics Data System (ADS)

Casasent, David; Telfer, Brian

1988-02-01

The storage capacity, noise performance, and synthesis of associative memories for image analysis are considered. Associative memory synthesis is shown to be very similar to that of linear discriminant functions used in pattern recognition. These lead to new associative memories and new associative memory synthesis and recollection vector encodings. Heteroassociative memories are emphasized in this paper, rather than autoassociative memories, since heteroassociative memories provide scene analysis decisions, rather than merely enhanced output images. The analysis of heteroassociative memories has been given little attention. Heteroassociative memory performance and storage capacity are shown to be quite different from those of autoassociative memories, with much more dependence on the recollection vectors used and less dependence on M/N. This allows several different and preferable synthesis techniques to be considered for associative memories. These new associative memory synthesis techniques and new techniques to update associative memories are included. We also introduce a new SNR performance measure that is preferable to conventional noise standard deviation ratios.

On the Capacity of Attention: Its Estimation and Its Role in Working Memory and Cognitive Aptitudes

PubMed Central

Cowan, Nelson; Elliott, Emily M.; Saults, J. Scott; Morey, Candice C.; Mattox, Sam; Hismjatullina, Anna; Conway, Andrew R.A.

2008-01-01

Working memory (WM) is the set of mental processes holding limited information in a temporarily accessible state in service of cognition. We provide a theoretical framework to understand the relation between WM and aptitude measures. The WM measures that have yielded high correlations with aptitudes include separate storage and processing task components, on the assumption that WM involves both storage and processing. We argue that the critical aspect of successful WM measures is that rehearsal and grouping processes are prevented, allowing a clearer estimate of how many separate chunks of information the focus of attention circumscribes at once. Storage-and-processing tasks correlate with aptitudes, according to this view, largely because the processing task prevents rehearsal and grouping of items to be recalled. In a developmental study, we document that several scope-of-attention measures that do not include a separate processing component, but nevertheless prevent efficient rehearsal or grouping, also correlate well with aptitudes and with storage-and-processing measures. So does digit span in children too young to rehearse. PMID:16039935

Memory Is Not Only about Storage.

ERIC Educational Resources Information Center

Huber, Kay L.

1993-01-01

The Atkinson-Shiffrin model of memory has three components: sensory, short term, and long term. Each memory process (such as encoding, storage, and retrieval) can be linked to specific teaching and learning strategies. (SK)

Statistical Description of Associative Memory

NASA Astrophysics Data System (ADS)

Samengo, Inés

2003-03-01

The storage of memories, in the brain, induces some kind of modification in the structural and functional properties of a neural network. Here, a few neuropsychological and neurophysiological experiments are reviewed, suggesting that the plastic changes taking place during memory storage are governed, among other things, by the correlations in the activity of a set of neurons. The Hopfield model is briefly described, showing the way the methods of statistical physics can be useful to describe the storage and retrieval of memories.

Artificial cognitive memory—changing from density driven to functionality driven

NASA Astrophysics Data System (ADS)

Shi, L. P.; Yi, K. J.; Ramanathan, K.; Zhao, R.; Ning, N.; Ding, D.; Chong, T. C.

2011-03-01

Increasing density based on bit size reduction is currently a main driving force for the development of data storage technologies. However, it is expected that all of the current available storage technologies might approach their physical limits in around 15 to 20 years due to miniaturization. To further advance the storage technologies, it is required to explore a new development trend that is different from density driven. One possible direction is to derive insights from biological counterparts. Unlike physical memories that have a single function of data storage, human memory is versatile. It contributes to functions of data storage, information processing, and most importantly, cognitive functions such as adaptation, learning, perception, knowledge generation, etc. In this paper, a brief review of current data storage technologies are presented, followed by discussions of future storage technology development trend. We expect that the driving force will evolve from density to functionality, and new memory modules associated with additional functions other than only data storage will appear. As an initial step toward building a future generation memory technology, we propose Artificial Cognitive Memory (ACM), a memory based intelligent system. We also present the characteristics of ACM, new technologies that can be used to develop ACM components such as bioinspired element cells (silicon, memristor, phase change, etc.), and possible methodologies to construct a biologically inspired hierarchical system.

Rethinking the connection between working memory and language impairment.

PubMed

Archibald, Lisa M D; Harder Griebeling, Katherine

2016-05-01

Working memory deficits have been found for children with specific language impairment (SLI) on tasks imposing increasing short-term memory load with or without additional, consistent (and simple) processing load. To examine the processing function of working memory in children with low language (LL) by employing tasks imposing increasing processing loads with constant storage demands individually adjusted based on each participant's short-term memory capacity. School-age groups with LL (n = 17) and typical language with either average (n = 28) or above-average nonverbal intelligence (n = 15) completed complex working memory-span tasks varying processing load while keeping storage demands constant, varying storage demands while keeping processing load constant, simple storage-span tasks, and measures of language and nonverbal intelligence. Teachers completed questionnaires about cognition and learning. Significantly lower scores were found for the LL than either matched group on storage-based tasks, but no group differences were found on the tasks varying processing load. Teachers' ratings of oral expression and mathematics abilities discriminated those who did or did not complete the most challenging cognitive tasks. The results implicate a deficit in the phonological storage but not in the central executive component of working memory for children with LL. Teacher ratings may reveal personality traits related to perseverance of effort in cognitive research. © 2015 Royal College of Speech and Language Therapists.

Technology breakthroughs in high performance metal-oxide-semiconductor devices for ultra-high density, low power non-volatile memory applications

NASA Astrophysics Data System (ADS)

Hong, Augustin Jinwoo

Non-volatile memory devices have attracted much attention because data can be retained without power consumption more than a decade. Therefore, non-volatile memory devices are essential to mobile electronic applications. Among state of the art non-volatile memory devices, NAND flash memory has earned the highest attention because of its ultra-high scalability and therefore its ultra-high storage capacity. However, human desire as well as market competition requires not only larger storage capacity but also lower power consumption for longer battery life time. One way to meet this human desire and extend the benefits of NAND flash memory is finding out new materials for storage layer inside the flash memory, which is called floating gate in the state of the art flash memory device. In this dissertation, we study new materials for the floating gate that can lower down the power consumption and increase the storage capacity at the same time. To this end, we employ various materials such as metal nanodot, metal thin film and graphene incorporating complementary-metal-oxide-semiconductor (CMOS) compatible processes. Experimental results show excellent memory effects at relatively low operating voltages. Detailed physics and analysis on experimental results are discussed. These new materials for data storage can be promising candidates for future non-volatile memory application beyond the state of the art flash technologies.

PIMS: Memristor-Based Processing-in-Memory-and-Storage.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cook, Jeanine

Continued progress in computing has augmented the quest for higher performance with a new quest for higher energy efficiency. This has led to the re-emergence of Processing-In-Memory (PIM) ar- chitectures that offer higher density and performance with some boost in energy efficiency. Past PIM work either integrated a standard CPU with a conventional DRAM to improve the CPU- memory link, or used a bit-level processor with Single Instruction Multiple Data (SIMD) control, but neither matched the energy consumption of the memory to the computation. We originally proposed to develop a new architecture derived from PIM that more effectively addressed energymore » efficiency for high performance scientific, data analytics, and neuromorphic applications. We also originally planned to implement a von Neumann architecture with arithmetic/logic units (ALUs) that matched the power consumption of an advanced storage array to maximize energy efficiency. Implementing this architecture in storage was our original idea, since by augmenting storage (in- stead of memory), the system could address both in-memory computation and applications that accessed larger data sets directly from storage, hence Processing-in-Memory-and-Storage (PIMS). However, as our research matured, we discovered several things that changed our original direc- tion, the most important being that a PIM that implements a standard von Neumann-type archi- tecture results in significant energy efficiency improvement, but only about a O(10) performance improvement. In addition to this, the emergence of new memory technologies moved us to propos- ing a non-von Neumann architecture, called Superstrider, implemented not in storage, but in a new DRAM technology called High Bandwidth Memory (HBM). HBM is a stacked DRAM tech- nology that includes a logic layer where an architecture such as Superstrider could potentially be implemented.« less

Threshold-voltage modulated phase change heterojunction for application of high density memory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yan, Baihan; Tong, Hao, E-mail: tonghao@hust.edu.cn; Qian, Hang

2015-09-28

Phase change random access memory is one of the most important candidates for the next generation non-volatile memory technology. However, the ability to reduce its memory size is compromised by the fundamental limitations inherent in the CMOS technology. While 0T1R configuration without any additional access transistor shows great advantages in improving the storage density, the leakage current and small operation window limit its application in large-scale arrays. In this work, phase change heterojunction based on GeTe and n-Si is fabricated to address those problems. The relationship between threshold voltage and doping concentration is investigated, and energy band diagrams and X-raymore » photoelectron spectroscopy measurements are provided to explain the results. The threshold voltage is modulated to provide a large operational window based on this relationship. The switching performance of the heterojunction is also tested, showing a good reverse characteristic, which could effectively decrease the leakage current. Furthermore, a reliable read-write-erase function is achieved during the tests. Phase change heterojunction is proposed for high-density memory, showing some notable advantages, such as modulated threshold voltage, large operational window, and low leakage current.« less

What pharmacological interventions indicate concerning the role of the perirhinal cortex in recognition memory

PubMed Central

Brown, M.W.; Barker, G.R.I.; Aggleton, J.P.; Warburton, E.C.

2012-01-01

Findings of pharmacological studies that have investigated the involvement of specific regions of the brain in recognition memory are reviewed. The particular emphasis of the review concerns what such studies indicate concerning the role of the perirhinal cortex in recognition memory. Most of the studies involve rats and most have investigated recognition memory for objects. Pharmacological studies provide a large body of evidence supporting the essential role of the perirhinal cortex in the acquisition, consolidation and retrieval of object recognition memory. Such studies provide increasingly detailed evidence concerning both the neurotransmitter systems and the underlying intracellular mechanisms involved in recognition memory processes. They have provided evidence in support of synaptic weakening as a major synaptic plastic process within perirhinal cortex underlying object recognition memory. They have also supplied confirmatory evidence that that there is more than one synaptic plastic process involved. The demonstrated necessity to long-term recognition memory of intracellular signalling mechanisms related to synaptic modification within perirhinal cortex establishes a central role for the region in the information storage underlying such memory. Perirhinal cortex is thereby established as an information storage site rather than solely a processing station. Pharmacological studies have also supplied new evidence concerning the detailed roles of other regions, including the hippocampus and the medial prefrontal cortex in different types of recognition memory tasks that include a spatial or temporal component. In so doing, they have also further defined the contribution of perirhinal cortex to such tasks. To date it appears that the contribution of perirhinal cortex to associative and temporal order memory reflects that in simple object recognition memory, namely that perirhinal cortex provides information concerning objects and their prior occurrence (novelty/familiarity). PMID:22841990

A three-dimensional ground-water-flow model modified to reduce computer-memory requirements and better simulate confining-bed and aquifer pinchouts

USGS Publications Warehouse

Leahy, P.P.

1982-01-01

The Trescott computer program for modeling groundwater flow in three dimensions has been modified to (1) treat aquifer and confining bed pinchouts more realistically and (2) reduce the computer memory requirements needed for the input data. Using the original program, simulation of aquifer systems with nonrectangular external boundaries may result in a large number of nodes that are not involved in the numerical solution of the problem, but require computer storage. (USGS)

A molecular shift register based on electron transfer

NASA Technical Reports Server (NTRS)

Hopfield, J. J.; Onuchic, Josenelson; Beratan, David N.

1988-01-01

An electronic shift-register memory at the molecular level is described. The memory elements are based on a chain of electron-transfer molecules and the information is shifted by photoinduced electron-transfer reactions. This device integrates designed electronic molecules onto a very large scale integrated (silicon microelectronic) substrate, providing an example of a 'molecular electronic device' that could actually be made. The design requirements for such a device and possible synthetic strategies are discussed. Devices along these lines should have lower energy usage and enhanced storage density.

Hardware support for collecting performance counters directly to memory

DOEpatents

Gara, Alan; Salapura, Valentina; Wisniewski, Robert W.

2012-09-25

Hardware support for collecting performance counters directly to memory, in one aspect, may include a plurality of performance counters operable to collect one or more counts of one or more selected activities. A first storage element may be operable to store an address of a memory location. A second storage element may be operable to store a value indicating whether the hardware should begin copying. A state machine may be operable to detect the value in the second storage element and trigger hardware copying of data in selected one or more of the plurality of performance counters to the memory location whose address is stored in the first storage element.

Plasma-Assisted Atomic Layer Deposition of High-Density Ni Nanoparticles for Amorphous In-Ga-Zn-O Thin Film Transistor Memory

NASA Astrophysics Data System (ADS)

Qian, Shi-Bing; Wang, Yong-Ping; Shao, Yan; Liu, Wen-Jun; Ding, Shi-Jin

2017-02-01

For the first time, the growth of Ni nanoparticles (NPs) was explored by plasma-assisted atomic layer deposition (ALD) technique using NiCp2 and NH3 precursors. Influences of substrate temperature and deposition cycles on ALD Ni NPs were studied by field emission scanning electron microscope and X-ray photoelectron spectroscopy. By optimizing the process parameters, high-density and uniform Ni NPs were achieved in the case of 280 °C substrate temperature and 50 deposition cycles, exhibiting a density of 1.5 × 1012 cm-2 and a small size of 3 4 nm. Further, the above Ni NPs were used as charge storage medium of amorphous indium-gallium-zinc oxide (a-IGZO) thin film transistor (TFT) memory, demonstrating a high storage capacity for electrons. In particular, the nonvolatile memory exhibited an excellent programming characteristic, e.g., a large threshold voltage shift of 8.03 V was obtained after being programmed at 17 V for 5 ms.

Using data tagging to improve the performance of Kanerva's sparse distributed memory

NASA Technical Reports Server (NTRS)

Rogers, David

1988-01-01

The standard formulation of Kanerva's sparse distributed memory (SDM) involves the selection of a large number of data storage locations, followed by averaging the data contained in those locations to reconstruct the stored data. A variant of this model is discussed, in which the predominant pattern is the focus of reconstruction. First, one architecture is proposed which returns the predominant pattern rather than the average pattern. However, this model will require too much storage for most uses. Next, a hybrid model is proposed, called tagged SDM, which approximates the results of the predominant pattern machine, but is nearly as efficient as Kanerva's original formulation. Finally, some experimental results are shown which confirm that significant improvements in the recall capability of SDM can be achieved using the tagged architecture.

Stimulated electronic transition concept for an erasable optical memory

NASA Technical Reports Server (NTRS)

Albin, Sacharia; Satira, James D.; Livingston, David L.; Shull, Thomas A.

1992-01-01

A new concept for an erasable optical memory is demonstrated using stimulated electronic transition (SET). Large bandgap semiconductors are suitable materials for the SET medium. The properties of MgS:Eu,Sm and SrS:Eu,Sm as possible media for the SET process are investigated. Quantum storage is achieved in the form of charges in deep levels in the medium and stimulated radiative recombination is used as the reading process. Unlike magneto-optic (M-O) and phase change (PC) processes, optical writing, reading and erasing are achieved without localized heating. The SET process will have an inherently faster data transfer rate and a higher storage density, and the medium will be more durable than the M-O and PC media. A possible application of the SET process in neural networks is also discussed.

Distributed trace using central performance counter memory

DOEpatents

Satterfield, David L; Sexton, James C

2013-10-22

A plurality of processing cores, are central storage unit having at least memory connected in a daisy chain manner, forming a daisy chain ring layout on an integrated chip. At least one of the plurality of processing cores places trace data on the daisy chain connection for transmitting the trace data to the central storage unit, and the central storage unit detects the trace data and stores the trace data in the memory co-located in with the central storage unit.

Distributed trace using central performance counter memory

DOEpatents

Satterfield, David L.; Sexton, James C.

2013-01-22

A plurality of processing cores, are central storage unit having at least memory connected in a daisy chain manner, forming a daisy chain ring layout on an integrated chip. At least one of the plurality of processing cores places trace data on the daisy chain connection for transmitting the trace data to the central storage unit, and the central storage unit detects the trace data and stores the trace data in the memory co-located in with the central storage unit.

Requirement of the Combination of Mushroom Body ? Lobe and a/ß Lobes for the Retrieval of Both Aversive and Appetitive Early Memories in "Drosophila"

ERIC Educational Resources Information Center

Xie, Zhiyong; Huang, Cheng; Ci, Bo; Lianzhang, Wang; Zhong, Yi

2013-01-01

Extensive studies of "Drosophila" mushroom body in formation and retrieval of olfactory memories allow us to delineate the functional logic for memory storage and retrieval. Currently, there is a questionable disassociation of circuits for memory storage and retrieval during "Drosophila" olfactory memory processing. Formation…

Hold-up power supply for flash memory

NASA Technical Reports Server (NTRS)

Ott, William E. (Inventor)

2004-01-01

A hold-up power supply for flash memory systems is provided. The hold-up power supply provides the flash memory with the power needed to temporarily operate when a power loss exists. This allows the flash memory system to complete any erasures and writes, and thus allows it to shut down gracefully. The hold-up power supply detects when a power loss on a power supply bus is occurring and supplies the power needed for the flash memory system to temporally operate. The hold-up power supply stores power in at least one capacitor. During normal operation, power from a high voltage supply bus is used to charge the storage capacitors. When a power supply loss is detected, the power supply bus is disconnected from the flash memory system. A hold-up controller controls the power flow from the storage capacitors to the flash memory system. The hold-up controller uses feedback to assure that the proper voltage is provided from the storage capacitors to the flash memory system. This power supplied by the storage capacitors allows the flash memory system to complete any erasures and writes, and thus allows the flash memory system to shut down gracefully.

Synaptic Scaling Enables Dynamically Distinct Short- and Long-Term Memory Formation

PubMed Central

Tetzlaff, Christian; Kolodziejski, Christoph; Timme, Marc; Tsodyks, Misha; Wörgötter, Florentin

2013-01-01

Memory storage in the brain relies on mechanisms acting on time scales from minutes, for long-term synaptic potentiation, to days, for memory consolidation. During such processes, neural circuits distinguish synapses relevant for forming a long-term storage, which are consolidated, from synapses of short-term storage, which fade. How time scale integration and synaptic differentiation is simultaneously achieved remains unclear. Here we show that synaptic scaling – a slow process usually associated with the maintenance of activity homeostasis – combined with synaptic plasticity may simultaneously achieve both, thereby providing a natural separation of short- from long-term storage. The interaction between plasticity and scaling provides also an explanation for an established paradox where memory consolidation critically depends on the exact order of learning and recall. These results indicate that scaling may be fundamental for stabilizing memories, providing a dynamic link between early and late memory formation processes. PMID:24204240

Synaptic scaling enables dynamically distinct short- and long-term memory formation.

PubMed

Tetzlaff, Christian; Kolodziejski, Christoph; Timme, Marc; Tsodyks, Misha; Wörgötter, Florentin

2013-10-01

Memory storage in the brain relies on mechanisms acting on time scales from minutes, for long-term synaptic potentiation, to days, for memory consolidation. During such processes, neural circuits distinguish synapses relevant for forming a long-term storage, which are consolidated, from synapses of short-term storage, which fade. How time scale integration and synaptic differentiation is simultaneously achieved remains unclear. Here we show that synaptic scaling - a slow process usually associated with the maintenance of activity homeostasis - combined with synaptic plasticity may simultaneously achieve both, thereby providing a natural separation of short- from long-term storage. The interaction between plasticity and scaling provides also an explanation for an established paradox where memory consolidation critically depends on the exact order of learning and recall. These results indicate that scaling may be fundamental for stabilizing memories, providing a dynamic link between early and late memory formation processes.

Working memory contributes to elevated motor activity in adults with ADHD: an examination of the role of central executive and storage/rehearsal processes.

PubMed

Hudec, Kristen L; Alderson, R Matt; Kasper, Lisa J; Patros, Connor H G

2014-05-01

The relationship between working memory (WM) and objectively measured motor activity was examined in adults with ADHD and healthy controls (HCs). Thirty-five adults (ADHD = 20, HC = 15) were grouped using self-report and collateral-report measures in addition to a semistructured clinical interview. All participants completed control conditions with minimal WM demands, and separate phonological (PH) and visuospatial (VS) WM tasks with recall demands ranging from four to seven stimuli. The ADHD group exhibited significantly more motor activity relative to the HC group, and both groups exhibited greater activity during PH and VS WM tasks, relative to control conditions. Finally, the central executive (CE) and PH storage/rehearsal subsystems were associated with large-magnitude between-group differences in activity. Findings suggest that increased demands on WM, particularly the CE and PH storage/rehearsal, contribute to ADHD-related hyperactivity, though a portion of excessive motor activity in adults with ADHD may occur independently of WM demands.

A multiplexed light-matter interface for fibre-based quantum networks

PubMed Central

Saglamyurek, Erhan; Grimau Puigibert, Marcelli; Zhou, Qiang; Giner, Lambert; Marsili, Francesco; Verma, Varun B.; Woo Nam, Sae; Oesterling, Lee; Nippa, David; Oblak, Daniel; Tittel, Wolfgang

2016-01-01

Processing and distributing quantum information using photons through fibre-optic or free-space links are essential for building future quantum networks. The scalability needed for such networks can be achieved by employing photonic quantum states that are multiplexed into time and/or frequency, and light-matter interfaces that are able to store and process such states with large time-bandwidth product and multimode capacities. Despite important progress in developing such devices, the demonstration of these capabilities using non-classical light remains challenging. Here, employing the atomic frequency comb quantum memory protocol in a cryogenically cooled erbium-doped optical fibre, we report the quantum storage of heralded single photons at a telecom-wavelength (1.53 μm) with a time-bandwidth product approaching 800. Furthermore, we demonstrate frequency-multimode storage and memory-based spectral-temporal photon manipulation. Notably, our demonstrations rely on fully integrated quantum technologies operating at telecommunication wavelengths. With improved storage efficiency, our light-matter interface may become a useful tool in future quantum networks. PMID:27046076

A multiplexed light-matter interface for fibre-based quantum networks.

PubMed

Saglamyurek, Erhan; Grimau Puigibert, Marcelli; Zhou, Qiang; Giner, Lambert; Marsili, Francesco; Verma, Varun B; Woo Nam, Sae; Oesterling, Lee; Nippa, David; Oblak, Daniel; Tittel, Wolfgang

2016-04-05

Processing and distributing quantum information using photons through fibre-optic or free-space links are essential for building future quantum networks. The scalability needed for such networks can be achieved by employing photonic quantum states that are multiplexed into time and/or frequency, and light-matter interfaces that are able to store and process such states with large time-bandwidth product and multimode capacities. Despite important progress in developing such devices, the demonstration of these capabilities using non-classical light remains challenging. Here, employing the atomic frequency comb quantum memory protocol in a cryogenically cooled erbium-doped optical fibre, we report the quantum storage of heralded single photons at a telecom-wavelength (1.53 μm) with a time-bandwidth product approaching 800. Furthermore, we demonstrate frequency-multimode storage and memory-based spectral-temporal photon manipulation. Notably, our demonstrations rely on fully integrated quantum technologies operating at telecommunication wavelengths. With improved storage efficiency, our light-matter interface may become a useful tool in future quantum networks.

A Comprehensive Study on Energy Efficiency and Performance of Flash-based SSD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Seon-Yeon; Kim, Youngjae; Urgaonkar, Bhuvan

2011-01-01

Use of flash memory as a storage medium is becoming popular in diverse computing environments. However, because of differences in interface, flash memory requires a hard-disk-emulation layer, called FTL (flash translation layer). Although the FTL enables flash memory storages to replace conventional hard disks, it induces significant computational and space overhead. Despite the low power consumption of flash memory, this overhead leads to significant power consumption in an overall storage system. In this paper, we analyze the characteristics of flash-based storage devices from the viewpoint of power consumption and energy efficiency by using various methodologies. First, we utilize simulation tomore » investigate the interior operation of flash-based storage of flash-based storages. Subsequently, we measure the performance and energy efficiency of commodity flash-based SSDs by using microbenchmarks to identify the block-device level characteristics and macrobenchmarks to reveal their filesystem level characteristics.« less

Effects of Anxiety on Memory Storage and Updating in Young Children

ERIC Educational Resources Information Center

Visu-Petra, Laura; Cheie, Lavinia; Benga, Oana; Alloway, Tracy Packiam

2011-01-01

The relationship between trait anxiety and memory functioning in young children was investigated. Two studies were conducted, using tasks tapping verbal and visual-spatial short-term memory (Study 1) and working memory (Study 2) in preschoolers. On the verbal storage tasks, there was a detrimental effect of anxiety on processing efficiency…

Memory Erasure Experiments Indicate a Critical Role of CaMKII in Memory Storage.

PubMed

Rossetti, Tom; Banerjee, Somdeb; Kim, Chris; Leubner, Megan; Lamar, Casey; Gupta, Pooja; Lee, Bomsol; Neve, Rachael; Lisman, John

2017-09-27

The abundant synaptic protein CaMKII is necessary for long-term potentiation (LTP) and memory. However, whether CaMKII is required only during initial processes or whether it also mediates memory storage remains unclear. The most direct test of a storage role is the erasure test. In this test, a putative memory molecule is inhibited after learning. The key prediction is that this should produce persistent memory erasure even after the inhibitory agent is removed. We conducted this test using transient viral (HSV) expression of dominant-negative CaMKII-alpha (K42M) in the hippocampus. This produced persistent erasure of conditioned place avoidance. As an additional test, we found that expression of activated CaMKII (T286D/T305A/T306A) impaired place avoidance, a result not expected if a process other than CaMKII stores memory. Our behavioral results, taken together with prior experiments on LTP, strongly support a critical role of CaMKII in LTP maintenance and memory storage. Copyright © 2017 Elsevier Inc. All rights reserved.

Computers, the Human Mind, and My In-Laws' House.

ERIC Educational Resources Information Center

Esque, Timm J.

1996-01-01

Discussion of human memory, computer memory, and the storage of information focuses on a metaphor that can account for memory without storage and can set the stage for systemic research around a more comprehensive, understandable theory. (Author/LRW)

Electronic shift register memory based on molecular electron-transfer reactions

NASA Technical Reports Server (NTRS)

Hopfield, J. J.; Onuchic, Jose Nelson; Beratan, David N.

1989-01-01

The design of a shift register memory at the molecular level is described in detail. The memory elements are based on a chain of electron-transfer molecules incorporated on a very large scale integrated (VLSI) substrate, and the information is shifted by photoinduced electron-transfer reactions. The design requirements for such a system are discussed, and several realistic strategies for synthesizing these systems are presented. The immediate advantage of such a hybrid molecular/VLSI device would arise from the possible information storage density. The prospect of considerable savings of energy per bit processed also exists. This molecular shift register memory element design solves the conceptual problems associated with integrating molecular size components with larger (micron) size features on a chip.

Short- and long-term memory contributions to immediate serial recognition: evidence from serial position effects.

PubMed

Purser, Harry; Jarrold, Christopher

2010-04-01

A long-standing body of research supports the existence of separable short- and long-term memory systems, relying on phonological and semantic codes, respectively. The aim of the current study was to measure the contribution of long-term knowledge to short-term memory performance by looking for evidence of phonologically and semantically coded storage within a short-term recognition task, among developmental samples. Each experimental trial presented 4-item lists. In Experiment 1 typically developing children aged 5 to 6 years old showed evidence of phonologically coded storage across all 4 serial positions, but evidence of semantically coded storage at Serial Positions 1 and 2. In a further experiment, a group of individuals with Down syndrome was investigated as a test case that might be expected to use semantic coding to support short-term storage, but these participants showed no evidence of semantically coded storage and evidenced phonologically coded storage only at Serial Position 4, suggesting that individuals with Down syndrome have a verbal short-term memory capacity of 1 item. Our results suggest that previous evidence of semantic effects on "short-term memory performance" does not reflect semantic coding in short-term memory itself, and provide an experimental method for researchers wishing to take a relatively pure measure of verbal short-term memory capacity, in cases where rehearsal is unlikely.

Evolution of costly explicit memory and cumulative culture.

PubMed

Nakamaru, Mayuko

2016-06-21

Humans can acquire new information and modify it (cumulative culture) based on their learning and memory abilities, especially explicit memory, through the processes of encoding, consolidation, storage, and retrieval. Explicit memory is categorized into semantic and episodic memories. Animals have semantic memory, while episodic memory is unique to humans and essential for innovation and the evolution of culture. As both episodic and semantic memory are needed for innovation, the evolution of explicit memory influences the evolution of culture. However, previous theoretical studies have shown that environmental fluctuations influence the evolution of imitation (social learning) and innovation (individual learning) and assume that memory is not an evolutionary trait. If individuals can store and retrieve acquired information properly, they can modify it and innovate new information. Therefore, being able to store and retrieve information is essential from the perspective of cultural evolution. However, if both storage and retrieval were too costly, forgetting and relearning would have an advantage over storing and retrieving acquired information. In this study, using mathematical analysis and individual-based simulations, we investigate whether cumulative culture can promote the coevolution of costly memory and social and individual learning, assuming that cumulative culture improves the fitness of each individual. The conclusions are: (1) without cumulative culture, a social learning cost is essential for the evolution of storage-retrieval. Costly storage-retrieval can evolve with individual learning but costly social learning does not evolve. When low-cost social learning evolves, the repetition of forgetting and learning is favored more than the evolution of costly storage-retrieval, even though a cultural trait improves the fitness. (2) When cumulative culture exists and improves fitness, storage-retrieval can evolve with social and/or individual learning, which is not influenced by the degree of the social learning cost. Whether individuals socially learn a low level of culture from observing a high or the low level of culture influences the evolution of memory and learning, especially individual learning. Copyright © 2016 Elsevier Ltd. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Juhee; Lee, Sungpyo; Lee, Moo Hyung

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 themore » 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.« less

Large-area, flexible imaging arrays constructed by light-charge organic memories

PubMed Central

Zhang, Lei; Wu, Ti; Guo, Yunlong; Zhao, Yan; Sun, Xiangnan; Wen, Yugeng; Yu, Gui; Liu, Yunqi

2013-01-01

Existing organic imaging circuits, which offer attractive benefits of light weight, low cost and flexibility, are exclusively based on phototransistor or photodiode arrays. One shortcoming of these photo-sensors is that the light signal should keep invariant throughout the whole pixel-addressing and reading process. As a feasible solution, we synthesized a new charge storage molecule and embedded it into a device, which we call light-charge organic memory (LCOM). In LCOM, the functionalities of photo-sensor and non-volatile memory are integrated. Thanks to the deliberate engineering of electronic structure and self-organization process at the interface, 92% of the stored charges, which are linearly controlled by the quantity of light, retain after 20000 s. The stored charges can also be non-destructively read and erased by a simple voltage program. These results pave the way to large-area, flexible imaging circuits and demonstrate a bright future of small molecular materials in non-volatile memory. PMID:23326636

Criteria for identifying the molecular basis of the engram (CaMKII, PKMzeta).

PubMed

Lisman, John

2017-11-29

The engram refers to the molecular changes by which a memory is stored in the brain. Substantial evidence suggests that memory involves learning-dependent changes at synapses, a process termed long-term potentiation (LTP). Thus, understanding the storages process that underlies LTP may provide insight into how the engram is stored. LTP involves induction, maintenance (storage), and expression sub-processes; special tests are required to specifically reveal properties of the storage process. The strongest of these is the Erasure test in which a transiently applied agent that attacks a putative storage molecule may lead to persistent erasure of previously induced LTP/memory. Two major hypotheses have been proposed for LTP/memory storage: the CaMKII and PKM-zeta hypotheses. After discussing the tests that can be used to identify the engram (Necessity test, Saturation/Occlusion test, Erasure test), the status of these hypotheses is evaluated, based on the literature on LTP and memory-guided behavior. Review of the literature indicates that all three tests noted above support the CaMKII hypothesis when done at both the LTP level and at the behavioral level. Taken together, the results strongly suggest that the engram is stored by an LTP process in which CaMKII is a critical memory storage molecule.

Which Working Memory Functions Predict Intelligence?

ERIC Educational Resources Information Center

Oberauer, Klaus; Sub, Heinz-Martin; Wilhelm, Oliver; Wittmann, Werner W.

2008-01-01

Investigates the relationship between three factors of working memory (storage and processing, relational integration, and supervision) and four factors of intelligence (reasoning, speed, memory, and creativity) using structural equation models. Relational integration predicted reasoning ability at least as well as the storage-and-processing…

Short-Term Memory: The "Storage" Component of Human Brain Responses Predicts Recall.

ERIC Educational Resources Information Center

Chapman, Robert M.; And Others

1978-01-01

Presents electrophysiological and behavioral evidence for a neural process related to storage in short-term memory. Predicting recall performance on the basis of the storage component of brain responses is presented. A list of references is also included. (HM)

Alcohol and Memory: Storage and State Dependency

ERIC Educational Resources Information Center

Parker, Elizabeth S.; And Others

1976-01-01

Effects of acute alcohol intoxication on the storage phase of memory were evaluated with two tasks that minimized response retrieval: unpaced paired-associate learning with highly available responses and forced-choice picture recognition. It was concluded that storage processes are sensitive to disruption by alcohol. (CHK)

Highly Efficient Coherent Optical Memory Based on Electromagnetically Induced Transparency

NASA Astrophysics Data System (ADS)

Hsiao, Ya-Fen; Tsai, Pin-Ju; Chen, Hung-Shiue; Lin, Sheng-Xiang; Hung, Chih-Chiao; Lee, Chih-Hsi; Chen, Yi-Hsin; Chen, Yong-Fan; Yu, Ite A.; Chen, Ying-Cheng

2018-05-01

Quantum memory is an important component in the long-distance quantum communication based on the quantum repeater protocol. To outperform the direct transmission of photons with quantum repeaters, it is crucial to develop quantum memories with high fidelity, high efficiency and a long storage time. Here, we achieve a storage efficiency of 92.0 (1.5)% for a coherent optical memory based on the electromagnetically induced transparency scheme in optically dense cold atomic media. We also obtain a useful time-bandwidth product of 1200, considering only storage where the retrieval efficiency remains above 50%. Both are the best record to date in all kinds of schemes for the realization of optical memory. Our work significantly advances the pursuit of a high-performance optical memory and should have important applications in quantum information science.

Highly Efficient Coherent Optical Memory Based on Electromagnetically Induced Transparency.

PubMed

Hsiao, Ya-Fen; Tsai, Pin-Ju; Chen, Hung-Shiue; Lin, Sheng-Xiang; Hung, Chih-Chiao; Lee, Chih-Hsi; Chen, Yi-Hsin; Chen, Yong-Fan; Yu, Ite A; Chen, Ying-Cheng

2018-05-04

Quantum memory is an important component in the long-distance quantum communication based on the quantum repeater protocol. To outperform the direct transmission of photons with quantum repeaters, it is crucial to develop quantum memories with high fidelity, high efficiency and a long storage time. Here, we achieve a storage efficiency of 92.0 (1.5)% for a coherent optical memory based on the electromagnetically induced transparency scheme in optically dense cold atomic media. We also obtain a useful time-bandwidth product of 1200, considering only storage where the retrieval efficiency remains above 50%. Both are the best record to date in all kinds of schemes for the realization of optical memory. Our work significantly advances the pursuit of a high-performance optical memory and should have important applications in quantum information science.

Faithful Solid State Optical Memory with Dynamically Decoupled Spin Wave Storage

NASA Astrophysics Data System (ADS)

Lovrić, Marko; Suter, Dieter; Ferrier, Alban; Goldner, Philippe

2013-07-01

We report a high fidelity optical memory in which dynamical decoupling is used to extend the storage time. This is demonstrated in a rare-earth doped crystal in which optical coherences were transferred to nuclear spin coherences and then protected against environmental noise by dynamical decoupling, leading to storage times of up to 4.2 ms. An interference experiment shows that relative phases of input pulses are preserved through the whole storage and retrieval process with a visibility ≈1, demonstrating the usefulness of dynamical decoupling for extending the storage time of quantum memories. We also show that dynamical decoupling sequences insensitive to initial spin coherence increase retrieval efficiency.

Faithful solid state optical memory with dynamically decoupled spin wave storage.

PubMed

Lovrić, Marko; Suter, Dieter; Ferrier, Alban; Goldner, Philippe

2013-07-12

We report a high fidelity optical memory in which dynamical decoupling is used to extend the storage time. This is demonstrated in a rare-earth doped crystal in which optical coherences were transferred to nuclear spin coherences and then protected against environmental noise by dynamical decoupling, leading to storage times of up to 4.2 ms. An interference experiment shows that relative phases of input pulses are preserved through the whole storage and retrieval process with a visibility ≈1, demonstrating the usefulness of dynamical decoupling for extending the storage time of quantum memories. We also show that dynamical decoupling sequences insensitive to initial spin coherence increase retrieval efficiency.

Quantum memory with optically trapped atoms.

PubMed

Chuu, Chih-Sung; Strassel, Thorsten; Zhao, Bo; Koch, Markus; Chen, Yu-Ao; Chen, Shuai; Yuan, Zhen-Sheng; Schmiedmayer, Jörg; Pan, Jian-Wei

2008-09-19

We report the experimental demonstration of quantum memory for collective atomic states in a far-detuned optical dipole trap. Generation of the collective atomic state is heralded by the detection of a Raman scattered photon and accompanied by storage in the ensemble of atoms. The optical dipole trap provides confinement for the atoms during the quantum storage while retaining the atomic coherence. We probe the quantum storage by cross correlation of the photon pair arising from the Raman scattering and the retrieval of the atomic state stored in the memory. Nonclassical correlations are observed for storage times up to 60 mus.

Associative Representational Plasticity in the Auditory Cortex: A Synthesis of Two Disciplines

ERIC Educational Resources Information Center

Weinberger, Norman M.

2007-01-01

Historically, sensory systems have been largely ignored as potential loci of information storage in the neurobiology of learning and memory. They continued to be relegated to the role of "sensory analyzers" despite consistent findings of associatively induced enhancement of responses in primary sensory cortices to behaviorally important signal…

High efficiency Raman memory by suppressing radiation trapping

NASA Astrophysics Data System (ADS)

Thomas, S. E.; Munns, J. H. D.; Kaczmarek, K. T.; Qiu, C.; Brecht, B.; Feizpour, A.; Ledingham, P. M.; Walmsley, I. A.; Nunn, J.; Saunders, D. J.

2017-06-01

Raman interactions in alkali vapours are used in applications such as atomic clocks, optical signal processing, generation of squeezed light and Raman quantum memories for temporal multiplexing. To achieve a strong interaction the alkali ensemble needs both a large optical depth and a high level of spin-polarisation. We implement a technique known as quenching using a molecular buffer gas which allows near-perfect spin-polarisation of over 99.5 % in caesium vapour at high optical depths of up to ˜ 2× {10}5; a factor of 4 higher than can be achieved without quenching. We use this system to explore efficient light storage with high gain in a GHz bandwidth Raman memory.

Application of holographic optical techniques to bulk memory.

NASA Technical Reports Server (NTRS)

Anderson, L. K.

1971-01-01

Current efforts to exploit the spatial redundancy and built-in imaging of holographic optical techniques to provide high information densities without critical alignment and tight mechanical tolerances are reviewed. Read-write-erase in situ operation is possible but is presently impractical because of limitations in available recording media. As these are overcome, it should prove feasible to build holographic bulk memories with mechanically replaceable hologram plates featuring very fast (less than 2 microsec) random access to large (greater than 100 million bit) data blocks and very high throughput (greater than 500 Mbit/sec). Using volume holographic storage it may eventually be possible to realize random-access mass memories which require no mechanical motion and yet provide very high capacity.

Improved memory word line configuration allows high storage density

NASA Technical Reports Server (NTRS)

1966-01-01

Plated wire memory word drive line allows high storage density, good plated wire transmission and a simplified memory plane configuration. A half-turn word drive line with a magnetic keeper is used. The ground plane provides the return path for both the word current and the plated wire transmission line.

Training of Attentional Filtering, but Not of Memory Storage, Enhances Working Memory Efficiency by Strengthening the Neuronal Gatekeeper Network.

PubMed

Schmicker, Marlen; Schwefel, Melanie; Vellage, Anne-Katrin; Müller, Notger G

2016-04-01

Memory training (MT) in older adults with memory deficits often leads to frustration and, therefore, is usually not recommended. Here, we pursued an alternative approach and looked for transfer effects of 1-week attentional filter training (FT) on working memory performance and its neuronal correlates in young healthy humans. The FT effects were compared with pure MT, which lacked the necessity to filter out irrelevant information. Before and after training, all participants performed an fMRI experiment that included a combined task in which stimuli had to be both filtered based on color and stored in memory. We found that training induced processing changes by biasing either filtering or storage. FT induced larger transfer effects on the untrained cognitive function than MT. FT increased neuronal activity in frontal parts of the neuronal gatekeeper network, which is proposed to hinder irrelevant information from being unnecessarily stored in memory. MT decreased neuronal activity in the BG part of the gatekeeper network but enhanced activity in the parietal storage node. We take these findings as evidence that FT renders working memory more efficient by strengthening the BG-prefrontal gatekeeper network. MT, on the other hand, simply stimulates storage of any kind of information. These findings illustrate a tight connection between working memory and attention, and they may open up new avenues for ameliorating memory deficits in patients with cognitive impairments.

Storage or Retrieval Deficit: The Yin and Yang of Amnesia

ERIC Educational Resources Information Center

Hardt, Oliver; Wang, Szu-Han; Nader, Karim

2009-01-01

To this day, it remains unresolved whether experimental amnesia reflects failed memory storage or the inability to retrieve otherwise intact memory. Methodological as well as conceptual reasons prevented deciding between these two alternatives: The absence of recovery from amnesia is typically taken as supporting storage impairment…

Data systems and computer science space data systems: Onboard memory and storage

NASA Technical Reports Server (NTRS)

Shull, Tom

1991-01-01

The topics are presented in viewgraph form and include the following: technical objectives; technology challenges; state-of-the-art assessment; mass storage comparison; SODR drive and system concepts; program description; vertical Bloch line (VBL) device concept; relationship to external programs; and backup charts for memory and storage.

New design strategy for reversible plasticity shape memory polymers with deformable glassy aggregates.

PubMed

Lin, Tengfei; Tang, Zhenghai; Guo, Baochun

2014-12-10

Reversible plasticity shape memory (RPSM) is a new concept in the study of shape memory performance behavior and describes a phenomenon in which shape memory polymers (SMPs) can undergo a large plastic deformation at room temperature and subsequently recover their original shape upon heating. To date, RPSM behavior has been demonstrated in only a few polymers. In the present study, we implement a new design strategy, in which deformable glassy hindered phenol (AO-80) aggregates are incorporated into an amorphous network of epoxidized natural rubber (ENR) cured with zinc diacrylate (ZDA), in order to achieve RPSM properties. We propose that AO-80 continuously tunes the glass transition temperature (Tg) and improves the chain mobility of the SMP, providing traction and anchoring the ENR chains by intermolecular hydrogen bonding interactions. The RPSM behavior of the amorphous SMPs is characterized, and the results demonstrate good fixity at large deformations (up to 300%) and excellent recovery upon heating. Large energy storage capacities at Td in these RPSM materials are demonstrated compared with those achieved at elevated temperature in traditional SMPs. Interestingly, the further revealed self-healing properties of these materials are closely related to their RPSM behavior.

A bio-inspired memory model for structural health monitoring

NASA Astrophysics Data System (ADS)

Zheng, Wei; Zhu, Yong

2009-04-01

Long-term structural health monitoring (SHM) systems need intelligent management of the monitoring data. By analogy with the way the human brain processes memories, we present a bio-inspired memory model (BIMM) that does not require prior knowledge of the structure parameters. The model contains three time-domain areas: a sensory memory area, a short-term memory area and a long-term memory area. First, the initial parameters of the structural state are specified to establish safety criteria. Then the large amount of monitoring data that falls within the safety limits is filtered while the data outside the safety limits are captured instantly in the sensory memory area. Second, disturbance signals are distinguished from danger signals in the short-term memory area. Finally, the stable data of the structural balance state are preserved in the long-term memory area. A strategy for priority scheduling via fuzzy c-means for the proposed model is then introduced. An experiment on bridge tower deformation demonstrates that the proposed model can be applied for real-time acquisition, limited-space storage and intelligent mining of the monitoring data in a long-term SHM system.

Structural Components of Synaptic Plasticity and Memory Consolidation

PubMed Central

Bailey, Craig H.; Kandel, Eric R.; Harris, Kristen M.

2015-01-01

Consolidation of implicit memory in the invertebrate Aplysia and explicit memory in the mammalian hippocampus are associated with remodeling and growth of preexisting synapses and the formation of new synapses. Here, we compare and contrast structural components of the synaptic plasticity that underlies these two distinct forms of memory. In both cases, the structural changes involve time-dependent processes. Thus, some modifications are transient and may contribute to early formative stages of long-term memory, whereas others are more stable, longer lasting, and likely to confer persistence to memory storage. In addition, we explore the possibility that trans-synaptic signaling mechanisms governing de novo synapse formation during development can be reused in the adult for the purposes of structural synaptic plasticity and memory storage. Finally, we discuss how these mechanisms set in motion structural rearrangements that prepare a synapse to strengthen the same memory and, perhaps, to allow it to take part in other memories as a basis for understanding how their anatomical representation results in the enhanced expression and storage of memories in the brain. PMID:26134321

Plasma-Assisted Atomic Layer Deposition of High-Density Ni Nanoparticles for Amorphous In-Ga-Zn-O Thin Film Transistor Memory.

PubMed

Qian, Shi-Bing; Wang, Yong-Ping; Shao, Yan; Liu, Wen-Jun; Ding, Shi-Jin

2017-12-01

For the first time, the growth of Ni nanoparticles (NPs) was explored by plasma-assisted atomic layer deposition (ALD) technique using NiCp 2 and NH 3 precursors. Influences of substrate temperature and deposition cycles on ALD Ni NPs were studied by field emission scanning electron microscope and X-ray photoelectron spectroscopy. By optimizing the process parameters, high-density and uniform Ni NPs were achieved in the case of 280 °C substrate temperature and 50 deposition cycles, exhibiting a density of ~1.5 × 10 12  cm -2 and a small size of 3~4 nm. Further, the above Ni NPs were used as charge storage medium of amorphous indium-gallium-zinc oxide (a-IGZO) thin film transistor (TFT) memory, demonstrating a high storage capacity for electrons. In particular, the nonvolatile memory exhibited an excellent programming characteristic, e.g., a large threshold voltage shift of 8.03 V was obtained after being programmed at 17 V for 5 ms.

Mathematical inference in one point microrheology

NASA Astrophysics Data System (ADS)

Hohenegger, Christel; McKinley, Scott

2016-11-01

Pioneered by the work of Mason and Weitz, one point passive microrheology has been successfully applied to obtaining estimates of the loss and storage modulus of viscoelastic fluids when the mean-square displacement obeys a local power law. Using numerical simulations of a fluctuating viscoelastic fluid model, we study the problem of recovering the mechanical parameters of the fluid's memory kernel using statistical inference like mean-square displacements and increment auto-correlation functions. Seeking a better understanding of the influence of the assumptions made in the inversion process, we mathematically quantify the uncertainty in traditional one point microrheology for simulated data and demonstrate that a large family of memory kernels yields the same statistical signature. We consider both simulated data obtained from a full viscoelastic fluid simulation of the unsteady Stokes equations with fluctuations and from a Generalized Langevin Equation of the particle's motion described by the same memory kernel. From the theory of inverse problems, we propose an alternative method that can be used to recover information about the loss and storage modulus and discuss its limitations and uncertainties. NSF-DMS 1412998.

Adult age differences in the storage of information in working memory.

PubMed

Foos, P W; Wright, L

1992-01-01

The performance of 97 young and 91 old persons were compared to determine if a deficiency in working memory resources for processing, storage, or allocation could be detected. Persons simultaneously performed a storage and one of two processing tasks while instructed to allocate resources to processing, storage, or both tasks. The storage task involved remembering the names of one, three, or five persons. Processing tasks involved solving addition problems presented on flashcards or answering common knowledge questions. Results showed increased age differences on the storage task as demands for resources increased but no differences on processing tasks. Individuals seemed unable to allocate resources as instructed. A comparison of young-old and old-old groups showed the same results as those obtained comparing young and old groups and support the hypothesis of a deficiency of storage, but not processing, resources in working memory for old, especially old-old, adults.

A wearable multiplexed silicon nonvolatile memory array using nanocrystal charge confinement

PubMed Central

Kim, Jaemin; Son, Donghee; Lee, Mincheol; Song, Changyeong; Song, Jun-Kyul; Koo, Ja Hoon; Lee, Dong Jun; Shim, Hyung Joon; Kim, Ji Hoon; Lee, Minbaek; Hyeon, Taeghwan; Kim, Dae-Hyeong

2016-01-01

Strategies for efficient charge confinement in nanocrystal floating gates to realize high-performance memory devices have been investigated intensively. However, few studies have reported nanoscale experimental validations of charge confinement in closely packed uniform nanocrystals and related device performance characterization. Furthermore, the system-level integration of the resulting devices with wearable silicon electronics has not yet been realized. We introduce a wearable, fully multiplexed silicon nonvolatile memory array with nanocrystal floating gates. The nanocrystal monolayer is assembled over a large area using the Langmuir-Blodgett method. Efficient particle-level charge confinement is verified with the modified atomic force microscopy technique. Uniform nanocrystal charge traps evidently improve the memory window margin and retention performance. Furthermore, the multiplexing of memory devices in conjunction with the amplification of sensor signals based on ultrathin silicon nanomembrane circuits in stretchable layouts enables wearable healthcare applications such as long-term data storage of monitored heart rates. PMID:26763827

Stably maintained dendritic spines are associated with lifelong memories

PubMed Central

Yang, Guang; Pan, Feng; Gan, Wen-Biao

2016-01-01

Changes in synaptic connections are considered essential for learning and memory formation1–6. However, it is unknown how neural circuits undergo continuous synaptic changes during learning while maintaining lifelong memories. Here we show, by following postsynaptic dendritic spines over time in the mouse cortex7–8, that learning and novel sensory experience lead to spine formation and elimination by a protracted process. The extent of spine remodelling correlates with behavioural improvement after learning, suggesting a crucial role of synaptic structural plasticity in memory formation and storage. Importantly, a small fraction of new spines induced by novel experience, together with most spines formed early during development and surviving experience-dependent elimination, are preserved throughout the entire life of an animal. These studies indicate that learning and daily sensory experience leave minute but permanent marks on cortical connections and suggest that lifelong memories are stored in largely stably connected synaptic networks. PMID:19946265

A wearable multiplexed silicon nonvolatile memory array using nanocrystal charge confinement.

PubMed

Kim, Jaemin; Son, Donghee; Lee, Mincheol; Song, Changyeong; Song, Jun-Kyul; Koo, Ja Hoon; Lee, Dong Jun; Shim, Hyung Joon; Kim, Ji Hoon; Lee, Minbaek; Hyeon, Taeghwan; Kim, Dae-Hyeong

2016-01-01

Strategies for efficient charge confinement in nanocrystal floating gates to realize high-performance memory devices have been investigated intensively. However, few studies have reported nanoscale experimental validations of charge confinement in closely packed uniform nanocrystals and related device performance characterization. Furthermore, the system-level integration of the resulting devices with wearable silicon electronics has not yet been realized. We introduce a wearable, fully multiplexed silicon nonvolatile memory array with nanocrystal floating gates. The nanocrystal monolayer is assembled over a large area using the Langmuir-Blodgett method. Efficient particle-level charge confinement is verified with the modified atomic force microscopy technique. Uniform nanocrystal charge traps evidently improve the memory window margin and retention performance. Furthermore, the multiplexing of memory devices in conjunction with the amplification of sensor signals based on ultrathin silicon nanomembrane circuits in stretchable layouts enables wearable healthcare applications such as long-term data storage of monitored heart rates.

Using electrophysiology to demonstrate that cuing affects long-term memory storage over the short term

PubMed Central

Maxcey, Ashleigh M.; Fukuda, Keisuke; Song, Won S.; Woodman, Geoffrey F.

2015-01-01

As researchers who study working memory, we often assume that participants keep a representation of an object in working memory when we present a cue that indicates that object will be tested in a couple of seconds. This intuitively accounts for how well people can remember a cued object relative to their memory for that same object presented without a cue. However, it is possible that this superior memory does not purely reflect storage of the cued object in working memory. We tested the hypothesis that cued presented during a stream of objects, followed by a short retention interval and immediate memory test, change how information is handled by long-term memory. We tested this hypothesis using a family of frontal event-related potentials (ERPs) believed to reflect long-term memory storage. We found that these frontal indices of long-term memory were sensitive to the task relevance of objects signaled by auditory cues, even when objects repeat frequently such that proactive interference was high. Our findings indicate the problematic nature of assuming process purity in the study of working memory, and demonstrate how frequent stimulus repetitions fail to isolate the role of working memory mechanisms. PMID:25604772

Emerging memories

NASA Astrophysics Data System (ADS)

Baldi, Livio; Bez, Roberto; Sandhu, Gurtej

2014-12-01

Memory is a key component of any data processing system. Following the classical Turing machine approach, memories hold both the data to be processed and the rules for processing them. In the history of microelectronics, the distinction has been rather between working memory, which is exemplified by DRAM, and storage memory, exemplified by NAND. These two types of memory devices now represent 90% of all memory market and 25% of the total semiconductor market, and have been the technology drivers in the last decades. Even if radically different in characteristics, they are however based on the same storage mechanism: charge storage, and this mechanism seems to be near to reaching its physical limits. The search for new alternative memory approaches, based on more scalable mechanisms, has therefore gained new momentum. The status of incumbent memory technologies and their scaling limitations will be discussed. Emerging memory technologies will be analyzed, starting from the ones that are already present for niche applications, and which are getting new attention, thanks to recent technology breakthroughs. Maturity level, physical limitations and potential for scaling will be compared to existing memories. At the end the possible future composition of memory systems will be discussed.

Using electrophysiology to demonstrate that cueing affects long-term memory storage over the short term.

PubMed

Maxcey, Ashleigh M; Fukuda, Keisuke; Song, Won S; Woodman, Geoffrey F

2015-10-01

As researchers who study working memory, we often assume that participants keep a representation of an object in working memory when we present a cue that indicates that the object will be tested in a couple of seconds. This intuitively accounts for how well people can remember a cued object, relative to their memory for that same object presented without a cue. However, it is possible that this superior memory does not purely reflect storage of the cued object in working memory. We tested the hypothesis that cues presented during a stream of objects, followed by a short retention interval and immediate memory test, can change how information is handled by long-term memory. We tested this hypothesis by using a family of frontal event-related potentials believed to reflect long-term memory storage. We found that these frontal indices of long-term memory were sensitive to the task relevance of objects signaled by auditory cues, even when the objects repeated frequently, such that proactive interference was high. Our findings indicate the problematic nature of assuming process purity in the study of working memory, and demonstrate that frequent stimulus repetitions fail to isolate the role of working memory mechanisms.

Structural Synaptic Plasticity Has High Memory Capacity and Can Explain Graded Amnesia, Catastrophic Forgetting, and the Spacing Effect

PubMed Central

Knoblauch, Andreas; Körner, Edgar; Körner, Ursula; Sommer, Friedrich T.

2014-01-01

Although already William James and, more explicitly, Donald Hebb's theory of cell assemblies have suggested that activity-dependent rewiring of neuronal networks is the substrate of learning and memory, over the last six decades most theoretical work on memory has focused on plasticity of existing synapses in prewired networks. Research in the last decade has emphasized that structural modification of synaptic connectivity is common in the adult brain and tightly correlated with learning and memory. Here we present a parsimonious computational model for learning by structural plasticity. The basic modeling units are “potential synapses” defined as locations in the network where synapses can potentially grow to connect two neurons. This model generalizes well-known previous models for associative learning based on weight plasticity. Therefore, existing theory can be applied to analyze how many memories and how much information structural plasticity can store in a synapse. Surprisingly, we find that structural plasticity largely outperforms weight plasticity and can achieve a much higher storage capacity per synapse. The effect of structural plasticity on the structure of sparsely connected networks is quite intuitive: Structural plasticity increases the “effectual network connectivity”, that is, the network wiring that specifically supports storage and recall of the memories. Further, this model of structural plasticity produces gradients of effectual connectivity in the course of learning, thereby explaining various cognitive phenomena including graded amnesia, catastrophic forgetting, and the spacing effect. PMID:24858841

Interpreting potential markers of storage and rehearsal: Implications for studies of verbal short-term memory and neuropsychological cases.

PubMed

Wang, Xiaoli; Logie, Robert H; Jarrold, Christopher

2016-08-01

Neuropsychological studies of verbal short-term memory have often focused on two signature effects - phonological similarity and word length - the absence of which has been taken to indicate problems in phonological storage and rehearsal respectively. In the present study we present a possible alternative reading of such data, namely that the absence of these effects can follow as a consequence of an individual's poor level of recall. Data from a large normative sample of 251 adult participants were re-analyzed under the assumption that the size of phonological similarity and word length effects are proportional to an individual's overall level of recall. For both manipulations, when proportionalized effects were plotted against memory span, the same function fit the data in both auditory and visual presentation conditions. Furthermore, two additional sets of single-case data were broadly comparable to those that would be expected for an individual's level of verbal short-term memory performance albeit with some variation across tasks. These findings indicate that the absolute magnitude of phonological similarity and word length effects depends on overall levels of recall, and that these effects are necessarily eliminated at low levels of verbal short-term memory performance. This has implications for how one interprets any variation in the size of these effects, and raises serious questions about the causal direction of any relationship between impaired verbal short-term memory and the absence of phonological similarity or word length effects.

Efficient packing of patterns in sparse distributed memory by selective weighting of input bits

NASA Technical Reports Server (NTRS)

Kanerva, Pentti

1991-01-01

When a set of patterns is stored in a distributed memory, any given storage location participates in the storage of many patterns. From the perspective of any one stored pattern, the other patterns act as noise, and such noise limits the memory's storage capacity. The more similar the retrieval cues for two patterns are, the more the patterns interfere with each other in memory, and the harder it is to separate them on retrieval. A method is described of weighting the retrieval cues to reduce such interference and thus to improve the separability of patterns that have similar cues.

Synergistic High Charge-Storage Capacity for Multi-level Flexible Organic Flash Memory

NASA Astrophysics Data System (ADS)

Kang, Minji; Khim, Dongyoon; Park, Won-Tae; Kim, Jihong; Kim, Juhwan; Noh, Yong-Young; Baeg, Kang-Jun; Kim, Dong-Yu

2015-07-01

Electret and organic floating-gate memories are next-generation flash storage mediums for printed organic complementary circuits. While each flash memory can be easily fabricated using solution processes on flexible plastic substrates, promising their potential for on-chip memory organization is limited by unreliable bit operation and high write loads. We here report that new architecture could improve the overall performance of organic memory, and especially meet high storage for multi-level operation. Our concept depends on synergistic effect of electrical characterization in combination with a polymer electret (poly(2-vinyl naphthalene) (PVN)) and metal nanoparticles (Copper). It is distinguished from mostly organic nano-floating-gate memories by using the electret dielectric instead of general tunneling dielectric for additional charge storage. The uniform stacking of organic layers including various dielectrics and poly(3-hexylthiophene) (P3HT) as an organic semiconductor, followed by thin-film coating using orthogonal solvents, greatly improve device precision despite easy and fast manufacture. Poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] as high-k blocking dielectric also allows reduction of programming voltage. The reported synergistic organic memory devices represent low power consumption, high cycle endurance, high thermal stability and suitable retention time, compared to electret and organic nano-floating-gate memory devices.

Synergistic High Charge-Storage Capacity for Multi-level Flexible Organic Flash Memory.

PubMed

Kang, Minji; Khim, Dongyoon; Park, Won-Tae; Kim, Jihong; Kim, Juhwan; Noh, Yong-Young; Baeg, Kang-Jun; Kim, Dong-Yu

2015-07-23

Electret and organic floating-gate memories are next-generation flash storage mediums for printed organic complementary circuits. While each flash memory can be easily fabricated using solution processes on flexible plastic substrates, promising their potential for on-chip memory organization is limited by unreliable bit operation and high write loads. We here report that new architecture could improve the overall performance of organic memory, and especially meet high storage for multi-level operation. Our concept depends on synergistic effect of electrical characterization in combination with a polymer electret (poly(2-vinyl naphthalene) (PVN)) and metal nanoparticles (Copper). It is distinguished from mostly organic nano-floating-gate memories by using the electret dielectric instead of general tunneling dielectric for additional charge storage. The uniform stacking of organic layers including various dielectrics and poly(3-hexylthiophene) (P3HT) as an organic semiconductor, followed by thin-film coating using orthogonal solvents, greatly improve device precision despite easy and fast manufacture. Poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] as high-k blocking dielectric also allows reduction of programming voltage. The reported synergistic organic memory devices represent low power consumption, high cycle endurance, high thermal stability and suitable retention time, compared to electret and organic nano-floating-gate memory devices.

A Comprehensive Investigation of Memory Impairment in Attention Deficit Hyperactivity Disorder and Oppositional Defiant Disorder

ERIC Educational Resources Information Center

Rhodes, Sinead M.; Park, Joanne; Seth, Sarah; Coghill, David R.

2012-01-01

Background: We conducted a comprehensive and systematic assessment of memory functioning in drug-naive boys with attention deficit hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD). Methods: Boys performed verbal and spatial working memory (WM) component (storage and central executive) and verbal and spatial storage load tasks,…

On the Law Relating Processing to Storage in Working Memory

ERIC Educational Resources Information Center

Barrouillet, Pierre; Portrat, Sophie; Camos, Valerie

2011-01-01

"Working memory" is usually defined in cognitive psychology as a system devoted to the simultaneous processing and maintenance of information. However, although many models of working memory have been put forward during the last decades, they often leave underspecified the dynamic interplay between processing and storage. Moreover, the account of…

Coherence time of over a second in a telecom-compatible quantum memory storage material

NASA Astrophysics Data System (ADS)

Rančić, Miloš; Hedges, Morgan P.; Ahlefeldt, Rose L.; Sellars, Matthew J.

2018-01-01

Quantum memories for light will be essential elements in future long-range quantum communication networks. These memories operate by reversibly mapping the quantum state of light onto the quantum transitions of a material system. For networks, the quantum coherence times of these transitions must be long compared to the network transmission times, approximately 100 ms for a global communication network. Due to a lack of a suitable storage material, a quantum memory that operates in the 1,550 nm optical fibre communication band with a storage time greater than 1 μs has not been demonstrated. Here we describe the spin dynamics of 167Er3+: Y2SiO5 in a high magnetic field and demonstrate that this material has the characteristics for a practical quantum memory in the 1,550 nm communication band. We observe a hyperfine coherence time of 1.3 s. We also demonstrate efficient spin pumping of the entire ensemble into a single hyperfine state, a requirement for broadband spin-wave storage. With an absorption of 70 dB cm-1 at 1,538 nm and Λ transitions enabling spin-wave storage, this material is the first candidate identified for an efficient, broadband quantum memory at telecommunication wavelengths.

Recent Advances of Flexible Data Storage Devices Based on Organic Nanoscaled Materials.

PubMed

Zhou, Li; Mao, Jingyu; Ren, Yi; Han, Su-Ting; Roy, Vellaisamy A L; Zhou, Ye

2018-03-01

Following the trend of miniaturization as per Moore's law, and facing the strong demand of next-generation electronic devices that should be highly portable, wearable, transplantable, and lightweight, growing endeavors have been made to develop novel flexible data storage devices possessing nonvolatile ability, high-density storage, high-switching speed, and reliable endurance properties. Nonvolatile organic data storage devices including memory devices on the basis of floating-gate, charge-trapping, and ferroelectric architectures, as well as organic resistive memory are believed to be favorable candidates for future data storage applications. In this Review, typical information on device structure, memory characteristics, device operation mechanisms, mechanical properties, challenges, and recent progress of the above categories of flexible data storage devices based on organic nanoscaled materials is summarized. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Contribution of underlying processes to improved visuospatial working memory associated with physical activity.

PubMed

Ji, Qingchun; Wang, Yingying; Guo, Wei; Zhou, Chenglin

2017-01-01

Working memory is critical for various cognitive processes and can be separated into two stages: short-term memory storage and manipulation processing. Although previous studies have demonstrated that increased physical activity (PA) improves working memory and that males outperform females on visuospatial working memory tasks, few studies have determined the contribution of the two underlying stages to the visuospatial working memory improvement associated with PA. Thus, the aims of the present study were to verify the relationship between physical activity and visuospatial working memory, determine whether one or both stages were affected by PA, and investigate any sex differences. A total of 56 undergraduate students were recruited for this study. Their scores on the International Physical Activity Questionnaire (IPAQ) were used to separate them into either a lower PA ( n  = 26; IPAQ score ≤3,000 metabolic equivalent [MET]-min/week) or higher PA ( n  = 30; IPAQ score >3,000 MET-min/week) group. Participants were required to complete three tasks: a visuospatial working memory task, a task that examines the short-term memory storage stage, and a mental rotation task that examines the active manipulation stage. Participants in the higher PA group maintained similar accuracy but displayed significantly faster reaction times (RT) than those in the lower PA group on the visuospatial working memory and manipulation tasks. By contrast, no difference was observed between groups on the short-term memory storage task. In addition, no effects of sex were detected. Our results confirm that PA was positively to visuospatial working memory and that this positive relationship was associated with more rapid cognitive processing during the manipulation stage, with little or no relationship between PA and the memory storage stage of visuospatial working memory.

Spatial profile of charge storage in organic field-effect transistor nonvolatile memory using polymer electret

NASA Astrophysics Data System (ADS)

She, Xiao-Jian; Liu, Jie; Zhang, Jing-Yu; Gao, Xu; Wang, Sui-Dong

2013-09-01

Spatial profile of the charge storage in the pentacene-based field-effect transistor nonvolatile memories using poly(2-vinyl naphthalene) electret is probed. The electron trapping into the electret after programming can be space dependent with more electron storage in the region closer to the contacts, and reducing the channel length is an effective approach to improve the memory performance. The deficient electron supply in pentacene is proposed to be responsible for the inhomogeneous electron storage in the electret. The hole trapping into the electret after erasing is spatially homogeneous, arising from the sufficient hole accumulation in the pentacene channel.

FPGA-based prototype storage system with phase change memory

NASA Astrophysics Data System (ADS)

Li, Gezi; Chen, Xiaogang; Chen, Bomy; Li, Shunfen; Zhou, Mi; Han, Wenbing; Song, Zhitang

2016-10-01

With the ever-increasing amount of data being stored via social media, mobile telephony base stations, and network devices etc. the database systems face severe bandwidth bottlenecks when moving vast amounts of data from storage to the processing nodes. At the same time, Storage Class Memory (SCM) technologies such as Phase Change Memory (PCM) with unique features like fast read access, high density, non-volatility, byte-addressability, positive response to increasing temperature, superior scalability, and zero standby leakage have changed the landscape of modern computing and storage systems. In such a scenario, we present a storage system called FLEET which can off-load partial or whole SQL queries to the storage engine from CPU. FLEET uses an FPGA rather than conventional CPUs to implement the off-load engine due to its highly parallel nature. We have implemented an initial prototype of FLEET with PCM-based storage. The results demonstrate that significant performance and CPU utilization gains can be achieved by pushing selected query processing components inside in PCM-based storage.

Mass Storage and Retrieval at Rome Laboratory

NASA Technical Reports Server (NTRS)

Kann, Joshua L.; Canfield, Brady W.; Jamberdino, Albert A.; Clarke, Bernard J.; Daniszewski, Ed; Sunada, Gary

1996-01-01

As the speed and power of modern digital computers continues to advance, the demands on secondary mass storage systems grow. In many cases, the limitations of existing mass storage reduce the overall effectiveness of the computing system. Image storage and retrieval is one important area where improved storage technologies are required. Three dimensional optical memories offer the advantage of large data density, on the order of 1 Tb/cm(exp 3), and faster transfer rates because of the parallel nature of optical recording. Such a system allows for the storage of multiple-Gbit sized images, which can be recorded and accessed at reasonable rates. Rome Laboratory is currently investigating several techniques to perform three-dimensional optical storage including holographic recording, two-photon recording, persistent spectral-hole burning, multi-wavelength DNA recording, and the use of bacteriorhodopsin as a recording material. In this paper, the current status of each of these on-going efforts is discussed. In particular, the potential payoffs as well as possible limitations are addressed.

Simple Atomic Quantum Memory Suitable for Semiconductor Quantum Dot Single Photons

NASA Astrophysics Data System (ADS)

Wolters, Janik; Buser, Gianni; Horsley, Andrew; Béguin, Lucas; Jöckel, Andreas; Jahn, Jan-Philipp; Warburton, Richard J.; Treutlein, Philipp

2017-08-01

Quantum memories matched to single photon sources will form an important cornerstone of future quantum network technology. We demonstrate such a memory in warm Rb vapor with on-demand storage and retrieval, based on electromagnetically induced transparency. With an acceptance bandwidth of δ f =0.66 GHz , the memory is suitable for single photons emitted by semiconductor quantum dots. In this regime, vapor cell memories offer an excellent compromise between storage efficiency, storage time, noise level, and experimental complexity, and atomic collisions have negligible influence on the optical coherences. Operation of the memory is demonstrated using attenuated laser pulses on the single photon level. For a 50 ns storage time, we measure ηe2 e 50 ns=3.4 (3 )% end-to-end efficiency of the fiber-coupled memory, with a total intrinsic efficiency ηint=17 (3 )%. Straightforward technological improvements can boost the end-to-end-efficiency to ηe 2 e≈35 %; beyond that, increasing the optical depth and exploiting the Zeeman substructure of the atoms will allow such a memory to approach near unity efficiency. In the present memory, the unconditional read-out noise level of 9 ×10-3 photons is dominated by atomic fluorescence, and for input pulses containing on average μ1=0.27 (4 ) photons, the signal to noise level would be unity.

Simple Atomic Quantum Memory Suitable for Semiconductor Quantum Dot Single Photons.

PubMed

Wolters, Janik; Buser, Gianni; Horsley, Andrew; Béguin, Lucas; Jöckel, Andreas; Jahn, Jan-Philipp; Warburton, Richard J; Treutlein, Philipp

2017-08-11

Quantum memories matched to single photon sources will form an important cornerstone of future quantum network technology. We demonstrate such a memory in warm Rb vapor with on-demand storage and retrieval, based on electromagnetically induced transparency. With an acceptance bandwidth of δf=0.66  GHz, the memory is suitable for single photons emitted by semiconductor quantum dots. In this regime, vapor cell memories offer an excellent compromise between storage efficiency, storage time, noise level, and experimental complexity, and atomic collisions have negligible influence on the optical coherences. Operation of the memory is demonstrated using attenuated laser pulses on the single photon level. For a 50 ns storage time, we measure η_{e2e}^{50  ns}=3.4(3)% end-to-end efficiency of the fiber-coupled memory, with a total intrinsic efficiency η_{int}=17(3)%. Straightforward technological improvements can boost the end-to-end-efficiency to η_{e2e}≈35%; beyond that, increasing the optical depth and exploiting the Zeeman substructure of the atoms will allow such a memory to approach near unity efficiency. In the present memory, the unconditional read-out noise level of 9×10^{-3} photons is dominated by atomic fluorescence, and for input pulses containing on average μ_{1}=0.27(4) photons, the signal to noise level would be unity.

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

PubMed Central

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

2015-01-01

The integral image, an intermediate image representation, has found extensive use in multi-scale local feature detection algorithms, such as Speeded-Up Robust Features (SURF), allowing fast computation of rectangular features at constant speed, independent of filter size. For resource-constrained real-time embedded vision systems, computation and storage of integral image presents several design challenges due to strict timing and hardware limitations. Although calculation of the integral image only consists of simple addition operations, the total number of operations is large owing to the generally large size of image data. Recursive equations allow substantial decrease in the number of operations but require calculation in a serial fashion. This paper presents two new hardware algorithms that are based on the decomposition of these recursive equations, allowing calculation of up to four integral image values in a row-parallel way without significantly increasing the number of operations. An efficient design strategy is also proposed for a parallel integral image computation unit to reduce the size of the required internal memory (nearly 35% for common HD video). Addressing the storage problem of integral image in embedded vision systems, the paper presents two algorithms which allow substantial decrease (at least 44.44%) in the memory requirements. Finally, the paper provides a case study that highlights the utility of the proposed architectures in embedded vision systems. PMID:26184211

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

PubMed

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

2015-07-10

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

Levels of processing and language modality specificity in working memory.

PubMed

Rudner, Mary; Karlsson, Thomas; Gunnarsson, Johan; Rönnberg, Jerker

2013-03-01

Neural networks underpinning working memory demonstrate sign language specific components possibly related to differences in temporary storage mechanisms. A processing approach to memory systems suggests that the organisation of memory storage is related to type of memory processing as well. In the present study, we investigated for the first time semantic, phonological and orthographic processing in working memory for sign- and speech-based language. During fMRI we administered a picture-based 2-back working memory task with Semantic, Phonological, Orthographic and Baseline conditions to 11 deaf signers and 20 hearing non-signers. Behavioural data showed poorer and slower performance for both groups in Phonological and Orthographic conditions than in the Semantic condition, in line with depth-of-processing theory. An exclusive masking procedure revealed distinct sign-specific neural networks supporting working memory components at all three levels of processing. The overall pattern of sign-specific activations may reflect a relative intermodality difference in the relationship between phonology and semantics influencing working memory storage and processing. Copyright © 2012 Elsevier Ltd. All rights reserved.

The contribution of temporary storage and executive processes to category learning.

PubMed

Wang, Tengfei; Ren, Xuezhu; Schweizer, Karl

2015-09-01

Three distinctly different working memory processes, temporary storage, mental shifting and inhibition, were proposed to account for individual differences in category learning. A sample of 213 participants completed a classic category learning task and two working memory tasks that were experimentally manipulated for tapping specific working memory processes. Fixed-links models were used to decompose data of the category learning task into two independent components representing basic performance and improvement in performance in category learning. Processes of working memory were also represented by fixed-links models. In a next step the three working memory processes were linked to components of category learning. Results from modeling analyses indicated that temporary storage had a significant effect on basic performance and shifting had a moderate effect on improvement in performance. In contrast, inhibition showed no effect on any component of the category learning task. These results suggest that temporary storage and the shifting process play different roles in the course of acquiring new categories. Copyright © 2015 Elsevier B.V. All rights reserved.

Highly-efficient quantum memory for polarization qubits in a spatially-multiplexed cold atomic ensemble.

PubMed

Vernaz-Gris, Pierre; Huang, Kun; Cao, Mingtao; Sheremet, Alexandra S; Laurat, Julien

2018-01-25

Quantum memory for flying optical qubits is a key enabler for a wide range of applications in quantum information. A critical figure of merit is the overall storage and retrieval efficiency. So far, despite the recent achievements of efficient memories for light pulses, the storage of qubits has suffered from limited efficiency. Here we report on a quantum memory for polarization qubits that combines an average conditional fidelity above 99% and efficiency around 68%, thereby demonstrating a reversible qubit mapping where more information is retrieved than lost. The qubits are encoded with weak coherent states at the single-photon level and the memory is based on electromagnetically-induced transparency in an elongated laser-cooled ensemble of cesium atoms, spatially multiplexed for dual-rail storage. This implementation preserves high optical depth on both rails, without compromise between multiplexing and storage efficiency. Our work provides an efficient node for future tests of quantum network functionalities and advanced photonic circuits.

Contralateral Delay Activity Tracks Fluctuations in Working Memory Performance.

PubMed

Adam, Kirsten C S; Robison, Matthew K; Vogel, Edward K

2018-01-08

Neural measures of working memory storage, such as the contralateral delay activity (CDA), are powerful tools in working memory research. CDA amplitude is sensitive to working memory load, reaches an asymptote at known behavioral limits, and predicts individual differences in capacity. An open question, however, is whether neural measures of load also track trial-by-trial fluctuations in performance. Here, we used a whole-report working memory task to test the relationship between CDA amplitude and working memory performance. If working memory failures are due to decision-based errors and retrieval failures, CDA amplitude would not differentiate good and poor performance trials when load is held constant. If failures arise during storage, then CDA amplitude should track both working memory load and trial-by-trial performance. As expected, CDA amplitude tracked load (Experiment 1), reaching an asymptote at three items. In Experiment 2, we tracked fluctuations in trial-by-trial performance. CDA amplitude was larger (more negative) for high-performance trials compared with low-performance trials, suggesting that fluctuations in performance were related to the successful storage of items. During working memory failures, participants oriented their attention to the correct side of the screen (lateralized P1) and maintained covert attention to the correct side during the delay period (lateralized alpha power suppression). Despite the preservation of attentional orienting, we found impairments consistent with an executive attention theory of individual differences in working memory capacity; fluctuations in executive control (indexed by pretrial frontal theta power) may be to blame for storage failures.

Case Study in Corporate Memory Recovery: Hanford Tank Farms Miscellaneous Underground Waste Storage Tanks - 15344

DOE Office of Scientific and Technical Information (OSTI.GOV)

Washenfelder, D. J.; Johnson, J. M.; Turknett, J. C.

In addition to managing the 177 underground waste storage tanks containing 212,000 m3 (56 million gal) of radioactive waste at the U. S. Department of Energy’s Hanford Site 200 Area Tank Farms, Washington River Protection Solutions LLC is responsible for managing numerous small catch tanks and special surveillance facilities. These are collectively known as “MUSTs” - Miscellaneous Underground Storage Tanks. The MUSTs typically collected drainage and flushes during waste transfer system piping changes; special surveillance facilities supported Tank Farm processes including post-World War II uranium recovery and later fission product recovery from tank wastes. Most were removed from service followingmore » deactivation of the single-shell tank system in 1980 and stabilized by pumping the remaining liquids from them. The MUSTs were isolated by blanking connecting transfer lines and adding weatherproofing to prevent rainwater entry. Over the next 30 years MUST operating records were dispersed into large electronic databases or transferred to the National Archives Regional Center in Seattle, Washington. During 2014 an effort to reacquire the historical bases for the MUSTs’ published waste volumes was undertaken. Corporate Memory Recovery from a variety of record sources allowed waste volumes to be initially determined for 21 MUSTs, and waste volumes to be adjusted for 37 others. Precursors and symptoms of Corporate Memory Loss were identified in the context of MUST records recovery.« less

Holographic memory for high-density data storage and high-speed pattern recognition

NASA Astrophysics Data System (ADS)

Gu, Claire

2002-09-01

As computers and the internet become faster and faster, more and more information is transmitted, received, and stored everyday. The demand for high density and fast access time data storage is pushing scientists and engineers to explore all possible approaches including magnetic, mechanical, optical, etc. Optical data storage has already demonstrated its potential in the competition against other storage technologies. CD and DVD are showing their advantages in the computer and entertainment market. What motivated the use of optical waves to store and access information is the same as the motivation for optical communication. Light or an optical wave has an enormous capacity (or bandwidth) to carry information because of its short wavelength and parallel nature. In optical storage, there are two types of mechanism, namely localized and holographic memories. What gives the holographic data storage an advantage over localized bit storage is the natural ability to read the stored information in parallel, therefore, meeting the demand for fast access. Another unique feature that makes the holographic data storage attractive is that it is capable of performing associative recall at an incomparable speed. Therefore, volume holographic memory is particularly suitable for high-density data storage and high-speed pattern recognition. In this paper, we review previous works on volume holographic memories and discuss the challenges for this technology to become a reality.

Eternal 5D data storage by ultrafast laser writing in glass

NASA Astrophysics Data System (ADS)

Zhang, J.; ČerkauskaitÄ--, A.; Drevinskas, R.; Patel, A.; Beresna, M.; Kazansky, P. G.

2016-03-01

Securely storing large amounts of information over relatively short timescales of 100 years, comparable to the span of the human memory, is a challenging problem. Conventional optical data storage technology used in CDs and DVDs has reached capacities of hundreds of gigabits per square inch, but its lifetime is limited to a decade. DNA based data storage can hold hundreds of terabytes per gram, but the durability is limited. The major challenge is the lack of appropriate combination of storage technology and medium possessing the advantages of both high capacity and long lifetime. The recording and retrieval of the digital data with a nearly unlimited lifetime was implemented by femtosecond laser nanostructuring of fused quartz. The storage allows unprecedented properties including hundreds of terabytes per disc data capacity, thermal stability up to 1000 °C, and virtually unlimited lifetime at room temperature opening a new era of eternal data archiving.

Brain region-specific activity patterns after recent or remote memory retrieval of auditory conditioned fear.

PubMed

Kwon, Jeong-Tae; Jhang, Jinho; Kim, Hyung-Su; Lee, Sujin; Han, Jin-Hee

2012-09-19

Memory is thought to be sparsely encoded throughout multiple brain regions forming unique memory trace. Although evidence has established that the amygdala is a key brain site for memory storage and retrieval of auditory conditioned fear memory, it remains elusive whether the auditory brain regions may be involved in fear memory storage or retrieval. To investigate this possibility, we systematically imaged the brain activity patterns in the lateral amygdala, MGm/PIN, and AuV/TeA using activity-dependent induction of immediate early gene zif268 after recent and remote memory retrieval of auditory conditioned fear. Consistent with the critical role of the amygdala in fear memory, the zif268 activity in the lateral amygdala was significantly increased after both recent and remote memory retrieval. Interesting, however, the density of zif268 (+) neurons in both MGm/PIN and AuV/TeA, particularly in layers IV and VI, was increased only after remote but not recent fear memory retrieval compared to control groups. Further analysis of zif268 signals in AuV/TeA revealed that conditioned tone induced stronger zif268 induction compared to familiar tone in each individual zif268 (+) neuron after recent memory retrieval. Taken together, our results support that the lateral amygdala is a key brain site for permanent fear memory storage and suggest that MGm/PIN and AuV/TeA might play a role for remote memory storage or retrieval of auditory conditioned fear, or, alternatively, that these auditory brain regions might have a different way of processing for familiar or conditioned tone information at recent and remote time phases.

Explicit processing demands reveal language modality-specific organization of working memory.

PubMed

Rudner, Mary; Rönnberg, Jerker

2008-01-01

The working memory model for Ease of Language Understanding (ELU) predicts that processing differences between language modalities emerge when cognitive demands are explicit. This prediction was tested in three working memory experiments with participants who were Deaf Signers (DS), Hearing Signers (HS), or Hearing Nonsigners (HN). Easily nameable pictures were used as stimuli to avoid confounds relating to sensory modality. Performance was largely similar for DS, HS, and HN, suggesting that previously identified intermodal differences may be due to differences in retention of sensory information. When explicit processing demands were high, differences emerged between DS and HN, suggesting that although working memory storage in both groups is sensitive to temporal organization, retrieval is not sensitive to temporal organization in DS. A general effect of semantic similarity was also found. These findings are discussed in relation to the ELU model.

Analog Nonvolatile Computer Memory Circuits

NASA Technical Reports Server (NTRS)

MacLeod, Todd

2007-01-01

In nonvolatile random-access memory (RAM) circuits of a proposed type, digital data would be stored in analog form in ferroelectric field-effect transistors (FFETs). This type of memory circuit would offer advantages over prior volatile and nonvolatile types: In a conventional complementary metal oxide/semiconductor static RAM, six transistors must be used to store one bit, and storage is volatile in that data are lost when power is turned off. In a conventional dynamic RAM, three transistors must be used to store one bit, and the stored bit must be refreshed every few milliseconds. In contrast, in a RAM according to the proposal, data would be retained when power was turned off, each memory cell would contain only two FFETs, and the cell could store multiple bits (the exact number of bits depending on the specific design). Conventional flash memory circuits afford nonvolatile storage, but they operate at reading and writing times of the order of thousands of conventional computer memory reading and writing times and, hence, are suitable for use only as off-line storage devices. In addition, flash memories cease to function after limited numbers of writing cycles. The proposed memory circuits would not be subject to either of these limitations. Prior developmental nonvolatile ferroelectric memories are limited to one bit per cell, whereas, as stated above, the proposed memories would not be so limited. The design of a memory circuit according to the proposal must reflect the fact that FFET storage is only partly nonvolatile, in that the signal stored in an FFET decays gradually over time. (Retention times of some advanced FFETs exceed ten years.) Instead of storing a single bit of data as either a positively or negatively saturated state in a ferroelectric device, each memory cell according to the proposal would store two values. The two FFETs in each cell would be denoted the storage FFET and the control FFET. The storage FFET would store an analog signal value, between the positive and negative FFET saturation values. This signal value would represent a numerical value of interest corresponding to multiple bits: for example, if the memory circuit were designed to distinguish among 16 different analog values, then each cell could store 4 bits. Simultaneously with writing the signal value in the storage FFET, a negative saturation signal value would be stored in the control FFET. The decay of this control-FFET signal from the saturation value would serve as a model of the decay, for use in regenerating the numerical value of interest from its decaying analog signal value. The memory circuit would include addressing, reading, and writing circuitry that would have features in common with the corresponding parts of other memory circuits, but would also have several distinctive features. The writing circuitry would include a digital-to-analog converter (DAC); the reading circuitry would include an analog-to-digital converter (ADC). For writing a numerical value of interest in a given cell, that cell would be addressed, the saturation value would be written in the control FFET in that cell, and the non-saturation analog value representing the numerical value of interest would be generated by use of the DAC and stored in the storage FFET in that cell. For reading the numerical value of interest stored in a given cell, the cell would be addressed, the ADC would convert the decaying control and storage analog signal values to digital values, and an associated fast digital processing circuit would regenerate the numerical value from digital values.

The storage and recall of auditory memory.

PubMed

Nebenzahl, I; Albeck, Y

1990-01-01

The architecture of the auditory memory is investigated. The auditory information is assumed to be represented by f-t patterns. With the help of a psycho-physical experiment it is demonstrated that the storage of these patterns is highly folded in the sense that a long signal is broken into many short stretches before being stored in the memory. Recognition takes place by correlating newly heard input in the short term memory to information previously stored in the long term memory. We show that this correlation is performed after the input is accumulated and held statically in the short term memory.

An upconverted photonic nonvolatile memory.

PubMed

Zhou, Ye; Han, Su-Ting; Chen, Xian; Wang, Feng; Tang, Yong-Bing; Roy, V A L

2014-08-21

Conventional flash memory devices are voltage driven and found to be unsafe for confidential data storage. To ensure the security of the stored data, there is a strong demand for developing novel nonvolatile memory technology for data encryption. Here we show a photonic flash memory device, based on upconversion nanocrystals, which is light driven with a particular narrow width of wavelength in addition to voltage bias. With the help of near-infrared light, we successfully manipulate the multilevel data storage of the flash memory device. These upconverted photonic flash memory devices exhibit high ON/OFF ratio, long retention time and excellent rewritable characteristics.

How Working Memory Relates to Children's Reading Comprehension: The Importance of Domain-Specificity in Storage and Processing

ERIC Educational Resources Information Center

Nouwens, Suzan; Groen, Margriet A.; Verhoeven, Ludo

2017-01-01

Working memory is considered a well-established predictor of individual variation in reading comprehension in children and adults. However, how storage and processing capacities of working memory in both the phonological and semantic domain relate to reading comprehension is still unclear. In the current study, we investigated the contribution of…

Down Syndrome and Short-Term Memory Impairment: A Storage or Retrieval Deficit?

ERIC Educational Resources Information Center

Adler, Sol; McDade, Hiram L.

1980-01-01

Three groups of eight Ss (Down's syndrome, CA control, and MA control) received a battery of tests to assess recall and recognition memory using either auditory or visual input with verbal and nonverbal responses. Results indicated that the Down's syndrome group possessed deficits in both storage and retrieval abilities, with storage of visually…

Influence of Synaptic Depression on Memory Storage Capacity

NASA Astrophysics Data System (ADS)

Otsubo, Yosuke; Nagata, Kenji; Oizumi, Masafumi; Okada, Masato

2011-08-01

Synaptic efficacy between neurons is known to change within a short time scale dynamically. Neurophysiological experiments show that high-frequency presynaptic inputs decrease synaptic efficacy between neurons. This phenomenon is called synaptic depression, a short term synaptic plasticity. Many researchers have investigated how the synaptic depression affects the memory storage capacity. However, the noise has not been taken into consideration in their analysis. By introducing ``temperature'', which controls the level of the noise, into an update rule of neurons, we investigate the effects of synaptic depression on the memory storage capacity in the presence of the noise. We analytically compute the storage capacity by using a statistical mechanics technique called Self Consistent Signal to Noise Analysis (SCSNA). We find that the synaptic depression decreases the storage capacity in the case of finite temperature in contrast to the case of the low temperature limit, where the storage capacity does not change.

Twin-bit via resistive random access memory in 16 nm FinFET logic technologies

NASA Astrophysics Data System (ADS)

Shih, Yi-Hong; Hsu, Meng-Yin; King, Ya-Chin; Lin, Chrong Jung

2018-04-01

A via resistive random access memory (RRAM) cell fully compatible with the standard CMOS logic process has been successfully demonstrated for high-density logic nonvolatile memory (NVM) modules in advanced FinFET circuits. In this new cell, the transition metal layers are formed on both sides of a via, given two storage bits per via. In addition to its compact cell area (1T + 14 nm × 32 nm), the twin-bit via RRAM cell features a low operation voltage, a large read window, good data retention, and excellent cycling capability. As fine alignments between mask layers become possible, the twin-bit via RRAM cell is expected to be highly scalable in advanced FinFET technology.

Sparse distributed memory overview

NASA Technical Reports Server (NTRS)

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.

Storage and retrieval of THz-bandwidth single photons using a room-temperature diamond quantum memory.

PubMed

England, Duncan G; Fisher, Kent A G; MacLean, Jean-Philippe W; Bustard, Philip J; Lausten, Rune; Resch, Kevin J; Sussman, Benjamin J

2015-02-06

We report the storage and retrieval of single photons, via a quantum memory, in the optical phonons of a room-temperature bulk diamond. The THz-bandwidth heralded photons are generated by spontaneous parametric down-conversion and mapped to phonons via a Raman transition, stored for a variable delay, and released on demand. The second-order correlation of the memory output is g((2))(0)=0.65±0.07, demonstrating a preservation of nonclassical photon statistics throughout storage and retrieval. The memory is low noise, high speed and broadly tunable; it therefore promises to be a versatile light-matter interface for local quantum processing applications.

Quantum storage of entangled telecom-wavelength photons in an erbium-doped optical fibre

NASA Astrophysics Data System (ADS)

Saglamyurek, Erhan; Jin, Jeongwan; Verma, Varun B.; Shaw, Matthew D.; Marsili, Francesco; Nam, Sae Woo; Oblak, Daniel; Tittel, Wolfgang

2015-02-01

The realization of a future quantum Internet requires the processing and storage of quantum information at local nodes and interconnecting distant nodes using free-space and fibre-optic links. Quantum memories for light are key elements of such quantum networks. However, to date, neither an atomic quantum memory for non-classical states of light operating at a wavelength compatible with standard telecom fibre infrastructure, nor a fibre-based implementation of a quantum memory, has been reported. Here, we demonstrate the storage and faithful recall of the state of a 1,532 nm wavelength photon entangled with a 795 nm photon, in an ensemble of cryogenically cooled erbium ions doped into a 20-m-long silica fibre, using a photon-echo quantum memory protocol. Despite its currently limited efficiency and storage time, our broadband light-matter interface brings fibre-based quantum networks one step closer to reality.

An elementary quantum network using robust nuclear spin qubits in diamond

NASA Astrophysics Data System (ADS)

Kalb, Norbert; Reiserer, Andreas; Humphreys, Peter; Blok, Machiel; van Bemmelen, Koen; Twitchen, Daniel; Markham, Matthew; Taminiau, Tim; Hanson, Ronald

Quantum registers containing multiple robust qubits can form the nodes of future quantum networks for computation and communication. Information storage within such nodes must be resilient to any type of local operation. Here we demonstrate multiple robust memories by employing five nuclear spins adjacent to a nitrogen-vacancy defect centre in diamond. We characterize the storage of quantum superpositions and their resilience to entangling attempts with the electron spin of the defect centre. The storage fidelity is found to be limited by the probabilistic electron spin reset after failed entangling attempts. Control over multiple memories is then utilized to encode states in decoherence protected subspaces with increased robustness. Furthermore we demonstrate memory control in two optically linked network nodes and characterize the storage capabilities of both memories in terms of the process fidelity with the identity. These results pave the way towards multi-qubit quantum algorithms in a remote network setting.

An Array Processing Theory of Memory, Thought, and Behavior Patterning: A Radically Reconstructive View.

ERIC Educational Resources Information Center

Allison, Dennis J.

A theory of memory is introduced, which seeks to respond to the shortcomings of existing theories based on metaphors. Memory is presented as a mechanism, a comparison process in which information held in some form of immediate storage (whether based on perception or previous cognition or both) is compared to previously stored long-term storage.…

Neural Plasticity and Memory: Is Memory Encoded in Hydrogen Bonding Patterns?

PubMed

Amtul, Zareen; Rahman, Atta-Ur

2016-02-01

Current models of memory storage recognize posttranslational modification vital for short-term and mRNA translation for long-lasting information storage. However, at the molecular level things are quite vague. A comprehensive review of the molecular basis of short and long-lasting synaptic plasticity literature leads us to propose that the hydrogen bonding pattern at the molecular level may be a permissive, vital step of memory storage. Therefore, we propose that the pattern of hydrogen bonding network of biomolecules (glycoproteins and/or DNA template, for instance) at the synapse is the critical edifying mechanism essential for short- and long-term memories. A novel aspect of this model is that nonrandom impulsive (or unplanned) synaptic activity functions as a synchronized positive-feedback rehearsal mechanism by revising the configurations of the hydrogen bonding network by tweaking the earlier tailored hydrogen bonds. This process may also maintain the elasticity of the related synapses involved in memory storage, a characteristic needed for such networks to alter intricacy and revise endlessly. The primary purpose of this review is to stimulate the efforts to elaborate the mechanism of neuronal connectivity both at molecular and chemical levels. © The Author(s) 2014.

The role of reduced working memory storage and processing resources in the associative memory deficit of older adults: simulation studies with younger adults.

PubMed

Hara, Yoko; Naveh-Benjamin, Moshe

2015-01-01

Previous research indicates that relative to younger adults, older adults show a larger decline in long-term memory (LTM) for associations than for the components that make up these associations. The purpose of the present study was to investigate whether we can impair associative memory performance in young adults by reducing their working memory (WM) resources, hence providing potential clues regarding the underlying causes of the associative memory deficit in older adults. With two experiments, we investigated whether we can reduce younger adults' long-term associative memory using secondary tasks in which either storage or processing WM loads were manipulated, while participants learned name-face pairs and then remembered the names, the faces, and the name-face associations. Results show that reducing either the storage or the processing resources of WM produced performance patterns of an associative long-term memory deficit in young adults. Furthermore, younger adults' associative memory deficit was a function of their performance on a working memory span task. These results indicate that one potential reason older adults have an associative deficit is a reduction in their WM resources but further research is needed to assess the mechanisms involved in age-related associative memory deficits.

Neural network based feed-forward high density associative memory

NASA Technical Reports Server (NTRS)

Daud, T.; Moopenn, A.; Lamb, J. L.; Ramesham, R.; Thakoor, A. P.

1987-01-01

A novel thin film approach to neural-network-based high-density associative memory is described. The information is stored locally in a memory matrix of passive, nonvolatile, binary connection elements with a potential to achieve a storage density of 10 to the 9th bits/sq cm. Microswitches based on memory switching in thin film hydrogenated amorphous silicon, and alternatively in manganese oxide, have been used as programmable read-only memory elements. Low-energy switching has been ascertained in both these materials. Fabrication and testing of memory matrix is described. High-speed associative recall approaching 10 to the 7th bits/sec and high storage capacity in such a connection matrix memory system is also described.

Upgrading the sleeping brain with targeted memory reactivation.

PubMed

Oudiette, Delphine; Paller, Ken A

2013-03-01

A fundamental feature of human memory is the propensity for beneficial changes in information storage after initial encoding. Recent research findings favor the possibility that memory consolidation during sleep is instrumental for actively maintaining the storehouse of memories that individuals carry through their lives. The information that ultimately remains available for retrieval may tend to be that which is reactivated during sleep. A novel source of support for this idea comes from demonstrations that neurocognitive processing during sleep can benefit memory storage when memories are covertly cued via auditory or olfactory stimulation. Investigations of these subtle manipulations of memory processing during sleep can help elucidate the mechanisms of memory preservation in the human brain. Copyright © 2013 Elsevier Ltd. All rights reserved.

Working Memory in Children with Cochlear Implants: Problems are in Storage, not Processing

PubMed Central

Nittrouer, Susan; Caldwell-Tarr, Amanda; Lowenstein, Joanna H

2013-01-01

Background There is growing consensus that hearing loss and consequent amplification likely interact with cognitive systems. A phenomenon often examined in regards to these potential interactions is working memory, modeled as consisting of one component responsible for storage of information and another component responsible for processing of that information. Signal degradation associated with cochlear implants should selectively inhibit storage without affecting processing. This study examined two hypotheses: (1) A single task can be used to measure storage and processing in working memory, with recall accuracy indexing storage and rate of recall indexing processing; (2) Storage is negatively impacted for children with CIs, but not processing. Method Two experiments were conducted. Experiment 1 included adults and children, 8 and 6 years of age, with NH. Procedures tested the prediction that accuracy of recall could index storage and rate of recall could index processing. Both measures were obtained during a serial-recall task using word lists designed to manipulate storage and processing demands independently: non-rhyming nouns were the standard condition; rhyming nouns were predicted to diminish storage capacity; and non-rhyming adjectives were predicted to increase processing load. Experiment 2 included 98 8-year-olds, 48 with NH and 50 with CIs, in the same serial-recall task using the non-rhyming and rhyming nouns. Results Experiment 1 showed that recall accuracy was poorest for the rhyming nouns and rate of recall was slowest for the non-rhyming adjectives, demonstrating that storage and processing can be indexed separately within a single task. In Experiment 2, children with CIs showed less accurate recall of serial order than children with NH, but rate of recall did not differ. Recall accuracy and rate of recall were not correlated in either experiment, reflecting independence of these mechanisms. Conclusions It is possible to measure the operations of storage and processing mechanisms in working memory in a single task, and only storage is impaired for children with CIs. These findings suggest that research and clinical efforts should focus on enhancing the saliency of representation for children with CIs. Direct instruction of syntax and semantics could facilitate storage in real-world working memory tasks. PMID:24090697

Working memory in children with cochlear implants: problems are in storage, not processing.

PubMed

Nittrouer, Susan; Caldwell-Tarr, Amanda; Lowenstein, Joanna H

2013-11-01

There is growing consensus that hearing loss and consequent amplification likely interact with cognitive systems. A phenomenon often examined in regards to these potential interactions is working memory, modeled as consisting of one component responsible for storage of information and another component responsible for processing of that information. Signal degradation associated with cochlear implants should selectively inhibit storage without affecting processing. This study examined two hypotheses: (1) A single task can be used to measure storage and processing in working memory, with recall accuracy indexing storage and rate of recall indexing processing; (2) Storage is negatively impacted for children with CIs, but not processing. Two experiments were conducted. Experiment 1 included adults and children, 8 and 6 years of age, with NH. Procedures tested the prediction that accuracy of recall could index storage and rate of recall could index processing. Both measures were obtained during a serial-recall task using word lists designed to manipulate storage and processing demands independently: non-rhyming nouns were the standard condition; rhyming nouns were predicted to diminish storage capacity; and non-rhyming adjectives were predicted to increase processing load. Experiment 2 included 98 8-year-olds, 48 with NH and 50 with CIs, in the same serial-recall task using the non-rhyming and rhyming nouns. Experiment 1 showed that recall accuracy was poorest for the rhyming nouns and rate of recall was slowest for the non-rhyming adjectives, demonstrating that storage and processing can be indexed separately within a single task. In Experiment 2, children with CIs showed less accurate recall of serial order than children with NH, but rate of recall did not differ. Recall accuracy and rate of recall were not correlated in either experiment, reflecting independence of these mechanisms. It is possible to measure the operations of storage and processing mechanisms in working memory in a single task, and only storage is impaired for children with CIs. These findings suggest that research and clinical efforts should focus on enhancing the saliency of representation for children with CIs. Direct instruction of syntax and semantics could facilitate storage in real-world working memory tasks. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Efficient Storage Scheme of Covariance Matrix during Inverse Modeling

NASA Astrophysics Data System (ADS)

Mao, D.; Yeh, T. J.

2013-12-01

During stochastic inverse modeling, the covariance matrix of geostatistical based methods carries the information about the geologic structure. Its update during iterations reflects the decrease of uncertainty with the incorporation of observed data. For large scale problem, its storage and update cost too much memory and computational resources. In this study, we propose a new efficient storage scheme for storage and update. Compressed Sparse Column (CSC) format is utilized to storage the covariance matrix, and users can assign how many data they prefer to store based on correlation scales since the data beyond several correlation scales are usually not very informative for inverse modeling. After every iteration, only the diagonal terms of the covariance matrix are updated. The off diagonal terms are calculated and updated based on shortened correlation scales with a pre-assigned exponential model. The correlation scales are shortened by a coefficient, i.e. 0.95, every iteration to show the decrease of uncertainty. There is no universal coefficient for all the problems and users are encouraged to try several times. This new scheme is tested with 1D examples first. The estimated results and uncertainty are compared with the traditional full storage method. In the end, a large scale numerical model is utilized to validate this new scheme.

Tracking the fear engram: the lateral amygdala is an essential locus of fear memory storage.

PubMed

Schafe, Glenn E; Doyère, Valérie; LeDoux, Joseph E

2005-10-26

Although it is believed that different types of memories are localized in discreet regions of the brain, concrete experimental evidence of the existence of such engrams is often elusive. Despite being one of the best characterized memory systems of the brain, the question of where fear memories are localized in the brain remains a hotly debated issue. Here, we combine site-specific behavioral pharmacology with multisite electrophysiological recording techniques to show that the lateral nucleus of the amygdala, long thought to be critical for the acquisition of fear memories, is also an essential locus of fear memory storage.

The sensory components of high-capacity iconic memory and visual working memory.

PubMed

Bradley, Claire; Pearson, Joel

2012-01-01

EARLY VISUAL MEMORY CAN BE SPLIT INTO TWO PRIMARY COMPONENTS: a high-capacity, short-lived iconic memory followed by a limited-capacity visual working memory that can last many seconds. Whereas a large number of studies have investigated visual working memory for low-level sensory features, much research on iconic memory has used more "high-level" alphanumeric stimuli such as letters or numbers. These two forms of memory are typically examined separately, despite an intrinsic overlap in their characteristics. Here, we used a purely sensory paradigm to examine visual short-term memory for 10 homogeneous items of three different visual features (color, orientation and motion) across a range of durations from 0 to 6 s. We found that the amount of information stored in iconic memory is smaller for motion than for color or orientation. Performance declined exponentially with longer storage durations and reached chance levels after ∼2 s. Further experiments showed that performance for the 10 items at 1 s was contingent on unperturbed attentional resources. In addition, for orientation stimuli, performance was contingent on the location of stimuli in the visual field, especially for short cue delays. Overall, our results suggest a smooth transition between an automatic, high-capacity, feature-specific sensory-iconic memory, and an effortful "lower-capacity" visual working memory.

ASIC-based architecture for the real-time computation of 2D convolution with large kernel size

NASA Astrophysics Data System (ADS)

Shao, Rui; Zhong, Sheng; Yan, Luxin

2015-12-01

Bidimensional convolution is a low-level processing algorithm of interest in many areas, but its high computational cost constrains the size of the kernels, especially in real-time embedded systems. This paper presents a hardware architecture for the ASIC-based implementation of 2-D convolution with medium-large kernels. Aiming to improve the efficiency of storage resources on-chip, reducing off-chip bandwidth of these two issues, proposed construction of a data cache reuse. Multi-block SPRAM to cross cached images and the on-chip ping-pong operation takes full advantage of the data convolution calculation reuse, design a new ASIC data scheduling scheme and overall architecture. Experimental results show that the structure can achieve 40× 32 size of template real-time convolution operations, and improve the utilization of on-chip memory bandwidth and on-chip memory resources, the experimental results show that the structure satisfies the conditions to maximize data throughput output , reducing the need for off-chip memory bandwidth.

High-performance Raman memory with spatio-temporal reversal

NASA Astrophysics Data System (ADS)

Vernaz-Gris, Pierre; Tranter, Aaron D.; Everett, Jesse L.; Leung, Anthony C.; Paul, Karun V.; Campbell, Geoff T.; Lam, Ping Koy; Buchler, Ben C.

2018-05-01

A number of techniques exist to use an ensemble of atoms as a quantum memory for light. Many of these propose to use backward retrieval as a way to improve the storage and recall efficiency. We report on a demonstration of an off-resonant Raman memory that uses backward retrieval to achieve an efficiency of $65\\pm6\\%$ at a storage time of one pulse duration. The memory has a characteristic decay time of 60 $\\mu$s, corresponding to a delay-bandwidth product of $160$.

Low latency and persistent data storage

DOEpatents

Fitch, Blake G; Franceschini, Michele M; Jagmohan, Ashish; Takken, Todd E

2014-02-18

Persistent data storage is provided by a method that includes receiving a low latency store command that includes write data. The write data is written to a first memory device that is implemented by a nonvolatile solid-state memory technology characterized by a first access speed. It is acknowledged that the write data has been successfully written to the first memory device. The write data is written to a second memory device that is implemented by a volatile memory technology. At least a portion of the data in the first memory device is written to a third memory device when a predetermined amount of data has been accumulated in the first memory device. The third memory device is implemented by a nonvolatile solid-state memory technology characterized by a second access speed that is slower than the first access speed.

Working memory and flexibility in awareness and attention.

PubMed

Bunting, Michael F; Cowan, Nelson

2005-06-01

We argue that attention and awareness form the basis of one type of working-memory storage. In contrast to models of working memory in which storage and retrieval occur effortlessly, we document that an attention-demanding goal conflict within a retrieval cue impairs recall from working memory. In a conceptual span task, semantic and color-name cues prompted recall of four consecutive words from a twelve-word list. The first-four, middle-four, and final-four words belonged to different semantic categories (e.g., body parts, animals, and tools) and were shown in different colors (e.g., red, blue, and green). In Experiment 1, the color of the cue matched that of cued items 75% of the time, and the rare mismatch impaired recall. In Experiment 2, though, the color of the cue matched that of the cued items only 25% of the time, and the now-more-frequent mismatches no longer mattered. These results are difficult to explain with passive storage alone and indicate that a processing difficulty impedes recall from working memory, presumably by distracting attention away from its storage function.

Reducing computational costs in large scale 3D EIT by using a sparse Jacobian matrix with block-wise CGLS reconstruction.

PubMed

Yang, C L; Wei, H Y; Adler, A; Soleimani, M

2013-06-01

Electrical impedance tomography (EIT) is a fast and cost-effective technique to provide a tomographic conductivity image of a subject from boundary current-voltage data. This paper proposes a time and memory efficient method for solving a large scale 3D EIT inverse problem using a parallel conjugate gradient (CG) algorithm. The 3D EIT system with a large number of measurement data can produce a large size of Jacobian matrix; this could cause difficulties in computer storage and the inversion process. One of challenges in 3D EIT is to decrease the reconstruction time and memory usage, at the same time retaining the image quality. Firstly, a sparse matrix reduction technique is proposed using thresholding to set very small values of the Jacobian matrix to zero. By adjusting the Jacobian matrix into a sparse format, the element with zeros would be eliminated, which results in a saving of memory requirement. Secondly, a block-wise CG method for parallel reconstruction has been developed. The proposed method has been tested using simulated data as well as experimental test samples. Sparse Jacobian with a block-wise CG enables the large scale EIT problem to be solved efficiently. Image quality measures are presented to quantify the effect of sparse matrix reduction in reconstruction results.

Visual working memory buffers information retrieved from visual long-term memory.

PubMed

Fukuda, Keisuke; Woodman, Geoffrey F

2017-05-16

Human memory is thought to consist of long-term storage and short-term storage mechanisms, the latter known as working memory. Although it has long been assumed that information retrieved from long-term memory is represented in working memory, we lack neural evidence for this and need neural measures that allow us to watch this retrieval into working memory unfold with high temporal resolution. Here, we show that human electrophysiology can be used to track information as it is brought back into working memory during retrieval from long-term memory. Specifically, we found that the retrieval of information from long-term memory was limited to just a few simple objects' worth of information at once, and elicited a pattern of neurophysiological activity similar to that observed when people encode new information into working memory. Our findings suggest that working memory is where information is buffered when being retrieved from long-term memory and reconcile current theories of memory retrieval with classic notions about the memory mechanisms involved.

Visual working memory buffers information retrieved from visual long-term memory

PubMed Central

Fukuda, Keisuke; Woodman, Geoffrey F.

2017-01-01

Human memory is thought to consist of long-term storage and short-term storage mechanisms, the latter known as working memory. Although it has long been assumed that information retrieved from long-term memory is represented in working memory, we lack neural evidence for this and need neural measures that allow us to watch this retrieval into working memory unfold with high temporal resolution. Here, we show that human electrophysiology can be used to track information as it is brought back into working memory during retrieval from long-term memory. Specifically, we found that the retrieval of information from long-term memory was limited to just a few simple objects’ worth of information at once, and elicited a pattern of neurophysiological activity similar to that observed when people encode new information into working memory. Our findings suggest that working memory is where information is buffered when being retrieved from long-term memory and reconcile current theories of memory retrieval with classic notions about the memory mechanisms involved. PMID:28461479

Face classification using electronic synapses

NASA Astrophysics Data System (ADS)

Yao, Peng; Wu, Huaqiang; Gao, Bin; Eryilmaz, Sukru Burc; Huang, Xueyao; Zhang, Wenqiang; Zhang, Qingtian; Deng, Ning; Shi, Luping; Wong, H.-S. Philip; Qian, He

2017-05-01

Conventional hardware platforms consume huge amount of energy for cognitive learning due to the data movement between the processor and the off-chip memory. Brain-inspired device technologies using analogue weight storage allow to complete cognitive tasks more efficiently. Here we present an analogue non-volatile resistive memory (an electronic synapse) with foundry friendly materials. The device shows bidirectional continuous weight modulation behaviour. Grey-scale face classification is experimentally demonstrated using an integrated 1024-cell array with parallel online training. The energy consumption within the analogue synapses for each iteration is 1,000 × (20 ×) lower compared to an implementation using Intel Xeon Phi processor with off-chip memory (with hypothetical on-chip digital resistive random access memory). The accuracy on test sets is close to the result using a central processing unit. These experimental results consolidate the feasibility of analogue synaptic array and pave the way toward building an energy efficient and large-scale neuromorphic system.

Face classification using electronic synapses.

PubMed

Yao, Peng; Wu, Huaqiang; Gao, Bin; Eryilmaz, Sukru Burc; Huang, Xueyao; Zhang, Wenqiang; Zhang, Qingtian; Deng, Ning; Shi, Luping; Wong, H-S Philip; Qian, He

2017-05-12

Conventional hardware platforms consume huge amount of energy for cognitive learning due to the data movement between the processor and the off-chip memory. Brain-inspired device technologies using analogue weight storage allow to complete cognitive tasks more efficiently. Here we present an analogue non-volatile resistive memory (an electronic synapse) with foundry friendly materials. The device shows bidirectional continuous weight modulation behaviour. Grey-scale face classification is experimentally demonstrated using an integrated 1024-cell array with parallel online training. The energy consumption within the analogue synapses for each iteration is 1,000 × (20 ×) lower compared to an implementation using Intel Xeon Phi processor with off-chip memory (with hypothetical on-chip digital resistive random access memory). The accuracy on test sets is close to the result using a central processing unit. These experimental results consolidate the feasibility of analogue synaptic array and pave the way toward building an energy efficient and large-scale neuromorphic system.

Nonvolatile semiconductor memory having three dimension charge confinement

DOEpatents

Dawson, L. Ralph; Osbourn, Gordon C.; Peercy, Paul S.; Weaver, Harry T.; Zipperian, Thomas E.

1991-01-01

A layered semiconductor device with a nonvolatile three dimensional memory comprises a storage channel which stores charge carriers. Charge carriers flow laterally through the storage channel from a source to a drain. Isolation material, either a Schottky barrier or a heterojunction, located in a trench of an upper layer controllably retains the charge within the a storage portion determined by the confining means. The charge is retained for a time determined by the isolation materials' nonvolatile characteristics or until a change of voltage on the isolation material and the source and drain permit a read operation. Flow of charge through an underlying sense channel is affected by the presence of charge within the storage channel, thus the presences of charge in the memory can be easily detected.

Multibit data storage states formed in plasma-treated MoS₂ transistors.

PubMed

Chen, Mikai; Nam, Hongsuk; Wi, Sungjin; Priessnitz, Greg; Gunawan, Ivan Manuel; Liang, Xiaogan

2014-04-22

New multibit memory devices are desirable for improving data storage density and computing speed. Here, we report that multilayer MoS2 transistors, when treated with plasmas, can dramatically serve as low-cost, nonvolatile, highly durable memories with binary and multibit data storage capability. We have demonstrated binary and 2-bit/transistor (or 4-level) data states suitable for year-scale data storage applications as well as 3-bit/transistor (or 8-level) data states for day-scale data storage. This multibit memory capability is hypothesized to be attributed to plasma-induced doping and ripple of the top MoS2 layers in a transistor, which could form an ambipolar charge-trapping layer interfacing the underlying MoS2 channel. This structure could enable the nonvolatile retention of charged carriers as well as the reversible modulation of polarity and amount of the trapped charge, ultimately resulting in multilevel data states in memory transistors. Our Kelvin force microscopy results strongly support this hypothesis. In addition, our research suggests that the programming speed of such memories can be improved by using nanoscale-area plasma treatment. We anticipate that this work would provide important scientific insights for leveraging the unique structural property of atomically layered two-dimensional materials in nanoelectronic applications.

Multi-port, optically addressed RAM

NASA Technical Reports Server (NTRS)

Johnston, Alan R. (Inventor); Nixon, Robert H. (Inventor); Bergman, Larry A. (Inventor); Esener, Sadik (Inventor)

1989-01-01

A random access memory addressing system utilizing optical links between memory and the read/write logic circuits comprises addressing circuits including a plurality of light signal sources, a plurality of optical gates including optical detectors associated with the memory cells, and a holographic optical element adapted to reflect and direct the light signals to the desired memory cell locations. More particularly, it is a multi-port, binary computer memory for interfacing with a plurality of computers. There are a plurality of storage cells for containing bits of binary information, the storage cells being disposed at the intersections of a plurality of row conductors and a plurality of column conductors. There is interfacing logic for receiving information from the computers directing access to ones of the storage cells. There are first light sources associated with the interfacing logic for transmitting a first light beam with the access information modulated thereon. First light detectors are associated with the storage cells for receiving the first light beam, for generating an electrical signal containing the access information, and for conducting the electrical signal to the one of the storage cells to which it is directed. There are holographic optical elements for reflecting the first light beam from the first light sources to the first light detectors.

DNA MemoChip: Long-Term and High Capacity Information Storage and Select Retrieval.

PubMed

Stefano, George B; Wang, Fuzhou; Kream, Richard M

2018-02-26

Over the course of history, human beings have never stopped seeking effective methods for information storage. From rocks to paper, and through the past several decades of using computer disks, USB sticks, and on to the thin silicon "chips" and "cloud" storage of today, it would seem that we have reached an era of efficiency for managing innumerable and ever-expanding data. Astonishingly, when tracing this technological path, one realizes that our ancient methods of informational storage far outlast paper (10,000 vs. 1,000 years, respectively), let alone the computer-based memory devices that only last, on average, 5 to 25 years. During this time of fast-paced information generation, it becomes increasingly difficult for current storage methods to retain such massive amounts of data, and to maintain appropriate speeds with which to retrieve it, especially when in demand by a large number of users. Others have proposed that DNA-based information storage provides a way forward for information retention as a result of its temporal stability. It is now evident that DNA represents a potentially economical and sustainable mechanism for storing information, as demonstrated by its decoding from a 700,000 year-old horse genome. The fact that the human genome is present in a cell, containing also the varied mitochondrial genome, indicates DNA's great potential for large data storage in a 'smaller' space.

DNA MemoChip: Long-Term and High Capacity Information Storage and Select Retrieval

PubMed Central

Wang, Fuzhou; Kream, Richard M.

2018-01-01

Over the course of history, human beings have never stopped seeking effective methods for information storage. From rocks to paper, and through the past several decades of using computer disks, USB sticks, and on to the thin silicon “chips” and “cloud” storage of today, it would seem that we have reached an era of efficiency for managing innumerable and ever-expanding data. Astonishingly, when tracing this technological path, one realizes that our ancient methods of informational storage far outlast paper (10,000 vs. 1,000 years, respectively), let alone the computer-based memory devices that only last, on average, 5 to 25 years. During this time of fast-paced information generation, it becomes increasingly difficult for current storage methods to retain such massive amounts of data, and to maintain appropriate speeds with which to retrieve it, especially when in demand by a large number of users. Others have proposed that DNA-based information storage provides a way forward for information retention as a result of its temporal stability. It is now evident that DNA represents a potentially economical and sustainable mechanism for storing information, as demonstrated by its decoding from a 700,000 year-old horse genome. The fact that the human genome is present in a cell, containing also the varied mitochondrial genome, indicates DNA’s great potential for large data storage in a ‘smaller’ space. PMID:29481548

Nonvolatile memory characteristics of organic thin film transistors using poly(2-hydroxyethyl methacrylate)-based polymer multilayer dielectric

NASA Astrophysics Data System (ADS)

Chen, Ying-Chih; Su, Yan-Kuin; Yu, Hsin-Chieh; Huang, Chun-Yuan; Huang, Tsung-Syun

2011-10-01

A wide hysteresis width characteristic (memory window) was observed in the organic thin film transistors (OTFTs) using poly(2-hydroxyethyl methacrylate) (PHEMA)-based polymer multilayers. In this study, a strong memory effect was also found in the pentacene-based OTFTs and the electric characteristics were improved by introducing PHEMA/poly(methyl methacrylate) (PMMA)/PHEMA trilayer to replace the conventional PHEMA monolayer or PMMA/PHEMA and PHEMA/PMMA bilayer as the dielectric layers of OTFTs. The memory effect was originated from the electron trapping and slow polarization of the dielectrics. The hydroxyl (-OH) groups inside the polymer dielectric were the main charge storage sites of the electrons. This charge-storage phenomenon could lead to a wide flat-band voltage shift (memory window, △VFB = 22 V) which is essential for the OTFTs' memory-related applications. Moreover, the fabricated transistors also exhibited significant switchable channel current due to the charge-storage and slow charge relaxation.

Feasibility study of molecular memory device based on DNA using methylation to store information

NASA Astrophysics Data System (ADS)

Jiang, Liming; Qiu, Wanzhi; Al-Dirini, Feras; Hossain, Faruque M.; Evans, Robin; Skafidas, Efstratios

2016-07-01

DNA, because of its robustness and dense information storage capability, has been proposed as a potential candidate for next-generation storage media. However, encoding information into the DNA sequence requires molecular synthesis technology, which to date is costly and prone to synthesis errors. Reading the DNA strand information is also complex. Ideally, DNA storage will provide methods for modifying stored information. Here, we conduct a feasibility study investigating the use of the DNA 5-methylcytosine (5mC) methylation state as a molecular memory to store information. We propose a new 1-bit memory device and study, based on the density functional theory and non-equilibrium Green's function method, the feasibility of electrically reading the information. Our results show that changes to methylation states lead to changes in the peak of negative differential resistance which can be used to interrogate memory state. Our work demonstrates a new memory concept based on methylation state which can be beneficial in the design of next generation DNA based molecular electronic memory devices.

Pseudo-orthogonalization of memory patterns for associative memory.

PubMed

Oku, Makito; Makino, Takaki; Aihara, Kazuyuki

2013-11-01

A new method for improving the storage capacity of associative memory models on a neural network is proposed. The storage capacity of the network increases in proportion to the network size in the case of random patterns, but, in general, the capacity suffers from correlation among memory patterns. Numerous solutions to this problem have been proposed so far, but their high computational cost limits their scalability. In this paper, we propose a novel and simple solution that is locally computable without any iteration. Our method involves XNOR masking of the original memory patterns with random patterns, and the masked patterns and masks are concatenated. The resulting decorrelated patterns allow higher storage capacity at the cost of the pattern length. Furthermore, the increase in the pattern length can be reduced through blockwise masking, which results in a small amount of capacity loss. Movie replay and image recognition are presented as examples to demonstrate the scalability of the proposed method.

Laser Card For Compact Optical Data Storage Systems

NASA Astrophysics Data System (ADS)

Drexler, Jerome

1982-05-01

The principal thrust of the optical data storage industry to date has been the 10 billion bit optical disc system. Mass memory has been the primary objective. Another objective that is beginning to demand recognition is compact memory of 1 million to 40 million bits--on a wallet-size, laser recordable card. Drexler Technology has addressed this opportunity and has succeeded in demonstrating laser writing and readback using a 16 mm by 85 mm recording stripe mounted on a card. The write/read apparatus was developed by SRI International. With this unit, 5 micron holes have been recorded using a 10 milliwatt, 830 nanometer semiconductor-diode laser. Data is entered on an Apple II keyboard using the ASCII code. The recorded reflective surface is scanned with the same laser at lower power to generate a reflected bit stream which is converted into alphanumerics and which appear on the monitor. We are pleased to report that the combination of the DREXONTM laser recordable card ("Laser Card"), the semiconductor-diode laser, arrays of large recorded holes, and human interactive data rates are all mutually compatible and point the way forward to economically feasible, compact, data-storage systems.

Method and device for maximizing memory system bandwidth by accessing data in a dynamically determined order

NASA Technical Reports Server (NTRS)

Schwab, Andrew J. (Inventor); Aylor, James (Inventor); Hitchcock, Charles Young (Inventor); Wulf, William A. (Inventor); McKee, Sally A. (Inventor); Moyer, Stephen A. (Inventor); Klenke, Robert (Inventor)

2000-01-01

A data processing system is disclosed which comprises a data processor and memory control device for controlling the access of information from the memory. The memory control device includes temporary storage and decision ability for determining what order to execute the memory accesses. The compiler detects the requirements of the data processor and selects the data to stream to the memory control device which determines a memory access order. The order in which to access said information is selected based on the location of information stored in the memory. The information is repeatedly accessed from memory and stored in the temporary storage until all streamed information is accessed. The information is stored until required by the data processor. The selection of the order in which to access information maximizes bandwidth and decreases the retrieval time.

Proactive Interference Does Not Meaningfully Distort Visual Working Memory Capacity Estimates in the Canonical Change Detection Task

PubMed Central

Lin, Po-Han; Luck, Steven J.

2012-01-01

The change detection task has become a standard method for estimating the storage capacity of visual working memory. Most researchers assume that this task isolates the properties of an active short-term storage system that can be dissociated from long-term memory systems. However, long-term memory storage may influence performance on this task. In particular, memory traces from previous trials may create proactive interference that sometimes leads to errors, thereby reducing estimated capacity. Consequently, the capacity of visual working memory may be higher than is usually thought, and correlations between capacity and other measures of cognition may reflect individual differences in proactive interference rather than individual differences in the capacity of the short-term storage system. Indeed, previous research has shown that change detection performance can be influenced by proactive interference under some conditions. The purpose of the present study was to determine whether the canonical version of the change detection task – in which the to-be-remembered information consists of simple, briefly presented features – is influenced by proactive interference. Two experiments were conducted using methods that ordinarily produce substantial evidence of proactive interference, but no proactive interference was observed. Thus, the canonical version of the change detection task can be used to assess visual working memory capacity with no meaningful influence of proactive interference. PMID:22403556

Proactive interference does not meaningfully distort visual working memory capacity estimates in the canonical change detection task.

PubMed

Lin, Po-Han; Luck, Steven J

2012-01-01

The change detection task has become a standard method for estimating the storage capacity of visual working memory. Most researchers assume that this task isolates the properties of an active short-term storage system that can be dissociated from long-term memory systems. However, long-term memory storage may influence performance on this task. In particular, memory traces from previous trials may create proactive interference that sometimes leads to errors, thereby reducing estimated capacity. Consequently, the capacity of visual working memory may be higher than is usually thought, and correlations between capacity and other measures of cognition may reflect individual differences in proactive interference rather than individual differences in the capacity of the short-term storage system. Indeed, previous research has shown that change detection performance can be influenced by proactive interference under some conditions. The purpose of the present study was to determine whether the canonical version of the change detection task - in which the to-be-remembered information consists of simple, briefly presented features - is influenced by proactive interference. Two experiments were conducted using methods that ordinarily produce substantial evidence of proactive interference, but no proactive interference was observed. Thus, the canonical version of the change detection task can be used to assess visual working memory capacity with no meaningful influence of proactive interference.

Optical storage with electromagnetically induced transparency in cold atoms at a high optical depth

NASA Astrophysics Data System (ADS)

Zhang, Shanchao; Zhou, Shuyu; Liu, Chang; Chen, J. F.; Wen, Jianming; Loy, M. M. T.; Wong, G. K. L.; Du, Shengwang

2012-06-01

We report experimental demonstration of efficient optical storage with electromagnetically induced transparency (EIT) in a dense cold ^85Rb atomic ensemble trapped in a two-dimensional magneto-optical trap. By varying the optical depth (OD) from 0 to 140, we observe that the optimal storage efficiency for coherent optical pulses has a saturation value of 50% as OD > 50. Our result is consistent with that obtained from hot vapor cell experiments which suggest that a four-wave mixing nonlinear process degrades the EIT storage coherence and efficiency. We apply this EIT quantum memory for narrow-band single photons with controllable waveforms, and obtain an optimal storage efficiency of 49±3% for single-photon wave packets. This is the highest single-photon storage efficiency reported up to today and brings the EIT atomic quantum memory close to practical application because an efficiency of above 50% is necessary to operate the memory within non-cloning regime and beat the classical limit.

Advanced Compact Holographic Data Storage System

NASA Technical Reports Server (NTRS)

Chao, Tien-Hsin; Zhou, Hanying; Reyes, George

2000-01-01

JPL, under current sponsorship from NASA Space Science and Earth Science Programs, is developing a high-density, nonvolatile and rad-hard Advanced Holographic Memory (AHM) system to enable large-capacity, high-speed, low power consumption, and read/write of data in a space environment. The entire read/write operation will be controlled with electro-optic mechanism without any moving parts. This CHDS will consist of laser diodes, photorefractive crystal, spatial light modulator, photodetector array, and I/O electronic interface. In operation, pages of information would be recorded and retrieved with random access and highspeed. The nonvolatile, rad-hard characteristics of the holographic memory will provide a revolutionary memory technology to enhance mission capabilities for all NASA's Earth Science Mission. In this paper, recent technology progress in developing this CHDS at JPL will be presented.

Low latency and persistent data storage

DOEpatents

Fitch, Blake G; Franceschini, Michele M; Jagmohan, Ashish; Takken, Todd

2014-11-04

Persistent data storage is provided by a computer program product that includes computer program code configured for receiving a low latency store command that includes write data. The write data is written to a first memory device that is implemented by a nonvolatile solid-state memory technology characterized by a first access speed. It is acknowledged that the write data has been successfully written to the first memory device. The write data is written to a second memory device that is implemented by a volatile memory technology. At least a portion of the data in the first memory device is written to a third memory device when a predetermined amount of data has been accumulated in the first memory device. The third memory device is implemented by a nonvolatile solid-state memory technology characterized by a second access speed that is slower than the first access speed.

Tracking the Time-Dependent Role of the Hippocampus in Memory Recall Using DREADDs.

PubMed

Varela, Carmen; Weiss, Sarah; Meyer, Retsina; Halassa, Michael; Biedenkapp, Joseph; Wilson, Matthew A; Goosens, Ki Ann; Bendor, Daniel

2016-01-01

The hippocampus is critical for the storage of new autobiographical experiences as memories. Following an initial encoding stage in the hippocampus, memories undergo a process of systems-level consolidation, which leads to greater stability through time and an increased reliance on neocortical areas for retrieval. The extent to which the retrieval of these consolidated memories still requires the hippocampus is unclear, as both spared and severely degraded remote memory recall have been reported following post-training hippocampal lesions. One difficulty in definitively addressing the role of the hippocampus in remote memory retrieval is the precision with which the entire volume of the hippocampal region can be inactivated. To address this issue, we used Designer Receptors Exclusively Activated by Designer Drugs (DREADDs), a chemical-genetic tool capable of highly specific neuronal manipulation over large volumes of brain tissue. We find that remote (>7 weeks after acquisition), but not recent (1-2 days after acquisition) contextual fear memories can be recalled after injection of the DREADD agonist (CNO) in animals expressing the inhibitory DREADD in the entire hippocampus. Our data demonstrate a time-dependent role of the hippocampus in memory retrieval, supporting the standard model of systems consolidation.

Tracking the Time-Dependent Role of the Hippocampus in Memory Recall Using DREADDs

PubMed Central

Varela, Carmen; Weiss, Sarah; Meyer, Retsina; Halassa, Michael; Biedenkapp, Joseph; Wilson, Matthew A.; Goosens, Ki Ann

2016-01-01

The hippocampus is critical for the storage of new autobiographical experiences as memories. Following an initial encoding stage in the hippocampus, memories undergo a process of systems-level consolidation, which leads to greater stability through time and an increased reliance on neocortical areas for retrieval. The extent to which the retrieval of these consolidated memories still requires the hippocampus is unclear, as both spared and severely degraded remote memory recall have been reported following post-training hippocampal lesions. One difficulty in definitively addressing the role of the hippocampus in remote memory retrieval is the precision with which the entire volume of the hippocampal region can be inactivated. To address this issue, we used Designer Receptors Exclusively Activated by Designer Drugs (DREADDs), a chemical-genetic tool capable of highly specific neuronal manipulation over large volumes of brain tissue. We find that remote (>7 weeks after acquisition), but not recent (1–2 days after acquisition) contextual fear memories can be recalled after injection of the DREADD agonist (CNO) in animals expressing the inhibitory DREADD in the entire hippocampus. Our data demonstrate a time-dependent role of the hippocampus in memory retrieval, supporting the standard model of systems consolidation. PMID:27145133

How the amygdala affects emotional memory by altering brain network properties.

PubMed

Hermans, Erno J; Battaglia, Francesco P; Atsak, Piray; de Voogd, Lycia D; Fernández, Guillén; Roozendaal, Benno

2014-07-01

The amygdala has long been known to play a key role in supporting memory for emotionally arousing experiences. For example, classical fear conditioning depends on neural plasticity within this anterior medial temporal lobe region. Beneficial effects of emotional arousal on memory, however, are not restricted to simple associative learning. Our recollection of emotional experiences often includes rich representations of, e.g., spatiotemporal context, visceral states, and stimulus-response associations. Critically, such memory features are known to bear heavily on regions elsewhere in the brain. These observations led to the modulation account of amygdala function, which postulates that amygdala activation enhances memory consolidation by facilitating neural plasticity and information storage processes in its target regions. Rodent work in past decades has identified the most important brain regions and neurochemical processes involved in these modulatory actions, and neuropsychological and neuroimaging work in humans has produced a large body of convergent data. Importantly, recent methodological developments make it increasingly realistic to monitor neural interactions underlying such modulatory effects as they unfold. For instance, functional connectivity network modeling in humans has demonstrated how information exchanges between the amygdala and specific target regions occur within the context of large-scale neural network interactions. Furthermore, electrophysiological and optogenetic techniques in rodents are beginning to make it possible to quantify and even manipulate such interactions with millisecond precision. In this paper we will discuss that these developments will likely lead to an updated view of the amygdala as a critical nexus within large-scale networks supporting different aspects of memory processing for emotionally arousing experiences. Copyright © 2014 Elsevier Inc. All rights reserved.

Non-volatile main memory management methods based on a file system.

PubMed

Oikawa, Shuichi

2014-01-01

There are upcoming non-volatile (NV) memory technologies that provide byte addressability and high performance. PCM, MRAM, and STT-RAM are such examples. Such NV memory can be used as storage because of its data persistency without power supply while it can be used as main memory because of its high performance that matches up with DRAM. There are a number of researches that investigated its uses for main memory and storage. They were, however, conducted independently. This paper presents the methods that enables the integration of the main memory and file system management for NV memory. Such integration makes NV memory simultaneously utilized as both main memory and storage. The presented methods use a file system as their basis for the NV memory management. We implemented the proposed methods in the Linux kernel, and performed the evaluation on the QEMU system emulator. The evaluation results show that 1) the proposed methods can perform comparably to the existing DRAM memory allocator and significantly better than the page swapping, 2) their performance is affected by the internal data structures of a file system, and 3) the data structures appropriate for traditional hard disk drives do not always work effectively for byte addressable NV memory. We also performed the evaluation of the effects caused by the longer access latency of NV memory by cycle-accurate full-system simulation. The results show that the effect on page allocation cost is limited if the increase of latency is moderate.

Multilevel resistive information storage and retrieval

DOEpatents

Lohn, Andrew; Mickel, Patrick R.

2016-08-09

The present invention relates to resistive random-access memory (RRAM or ReRAM) systems, as well as methods of employing multiple state variables to form degenerate states in such memory systems. The methods herein allow for precise write and read steps to form multiple state variables, and these steps can be performed electrically. Such an approach allows for multilevel, high density memory systems with enhanced information storage capacity and simplified information retrieval.

Photographic memory: The storage and retrieval of data

NASA Technical Reports Server (NTRS)

Horton, J.

1984-01-01

The concept of density encoding digital data in a mass-storage computer peripheral is proposed. This concept requires that digital data be encoded as distinguishable density levels (DDLS) of the film to be used as the storage medium. These DDL's are then recorded on the film in relatively large pixels. Retrieval of the data would be accomplished by scanning the photographic record using a relatively small aperture. Multiplexing of the pixels is used to store data of a range greater than the number of DDL's supportable by the film in question. Although a cartographic application is used as an example for the photographic storage of data, any digital data can be stored in a like manner. When the data is inherently spatially-distributed, the aptness of the proposed scheme is even more evident. In such a case, human-readability is an advantage which can be added to those mentioned earlier: speed of acquisition, ease of implementation, and cost effectiveness.

The synaptic plasticity and memory hypothesis: encoding, storage and persistence

PubMed Central

Takeuchi, Tomonori; Duszkiewicz, Adrian J.; Morris, Richard G. M.

2014-01-01

The synaptic plasticity and memory hypothesis asserts that activity-dependent synaptic plasticity is induced at appropriate synapses during memory formation and is both necessary and sufficient for the encoding and trace storage of the type of memory mediated by the brain area in which it is observed. Criteria for establishing the necessity and sufficiency of such plasticity in mediating trace storage have been identified and are here reviewed in relation to new work using some of the diverse techniques of contemporary neuroscience. Evidence derived using optical imaging, molecular-genetic and optogenetic techniques in conjunction with appropriate behavioural analyses continues to offer support for the idea that changing the strength of connections between neurons is one of the major mechanisms by which engrams are stored in the brain. PMID:24298167

Feasibility study of current pulse induced 2-bit/4-state multilevel programming in phase-change memory

NASA Astrophysics Data System (ADS)

Liu, Yan; Fan, Xi; Chen, Houpeng; Wang, Yueqing; Liu, Bo; Song, Zhitang; Feng, Songlin

2017-08-01

In this brief, multilevel data storage for phase-change memory (PCM) has attracted more attention in the memory market to implement high capacity memory system and reduce cost-per-bit. In this work, we present a universal programing method of SET stair-case current pulse in PCM cells, which can exploit the optimum programing scheme to achieve 2-bit/ 4state resistance-level with equal logarithm interval. SET stair-case waveform can be optimized by TCAD real time simulation to realize multilevel data storage efficiently in an arbitrary phase change material. Experimental results from 1 k-bit PCM test-chip have validated the proposed multilevel programing scheme. This multilevel programming scheme has improved the information storage density, robustness of resistance-level, energy efficient and avoiding process complexity.

The storage system of PCM based on random access file system

NASA Astrophysics Data System (ADS)

Han, Wenbing; Chen, Xiaogang; Zhou, Mi; Li, Shunfen; Li, Gezi; Song, Zhitang

2016-10-01

Emerging memory technologies such as Phase change memory (PCM) tend to offer fast, random access to persistent storage with better scalability. It's a hot topic of academic and industrial research to establish PCM in storage hierarchy to narrow the performance gap. However, the existing file systems do not perform well with the emerging PCM storage, which access storage medium via a slow, block-based interface. In this paper, we propose a novel file system, RAFS, to bring about good performance of PCM, which is built in the embedded platform. We attach PCM chips to the memory bus and build RAFS on the physical address space. In the proposed file system, we simplify traditional system architecture to eliminate block-related operations and layers. Furthermore, we adopt memory mapping and bypassed page cache to reduce copy overhead between the process address space and storage device. XIP mechanisms are also supported in RAFS. To the best of our knowledge, we are among the first to implement file system on real PCM chips. We have analyzed and evaluated its performance with IOZONE benchmark tools. Our experimental results show that the RAFS on PCM outperforms Ext4fs on SDRAM with small record lengths. Based on DRAM, RAFS is significantly faster than Ext4fs by 18% to 250%.

BAF53b, a Neuron-Specific Nucleosome Remodeling Factor, Is Induced after Learning and Facilitates Long-Term Memory Consolidation.

PubMed

Yoo, Miran; Choi, Kwang-Yeon; Kim, Jieun; Kim, Mujun; Shim, Jaehoon; Choi, Jun-Hyeok; Cho, Hye-Yeon; Oh, Jung-Pyo; Kim, Hyung-Su; Kaang, Bong-Kiun; Han, Jin-Hee

2017-03-29

Although epigenetic mechanisms of gene expression regulation have recently been implicated in memory consolidation and persistence, the role of nucleosome-remodeling is largely unexplored. Recent studies show that the functional loss of BAF53b, a postmitotic neuron-specific subunit of the BAF nucleosome-remodeling complex, results in the deficit of consolidation of hippocampus-dependent memory and cocaine-associated memory in the rodent brain. However, it is unclear whether BAF53b expression is regulated during memory formation and how BAF53b regulates fear memory in the amygdala, a key brain site for fear memory encoding and storage. To address these questions, we used viral vector approaches to either decrease or increase BAF53b function specifically in the lateral amygdala of adult mice in auditory fear conditioning paradigm. Knockdown of Baf53b before training disrupted long-term memory formation with no effect on short-term memory, basal synaptic transmission, and spine structures. We observed in our qPCR analysis that BAF53b was induced in the lateral amygdala neurons at the late consolidation phase after fear conditioning. Moreover, transient BAF53b overexpression led to persistently enhanced memory formation, which was accompanied by increase in thin-type spine density. Together, our results provide the evidence that BAF53b is induced after learning, and show that such increase of BAF53b level facilitates memory consolidation likely by regulating learning-related spine structural plasticity. SIGNIFICANCE STATEMENT Recent works in the rodent brain begin to link nucleosome remodeling-dependent epigenetic mechanism to memory consolidation. Here we show that BAF53b, an epigenetic factor involved in nucleosome remodeling, is induced in the lateral amygdala neurons at the late phase of consolidation after fear conditioning. Using specific gene knockdown or overexpression approaches, we identify the critical role of BAF53b in the lateral amygdala neurons for memory consolidation during long-term memory formation. Our results thus provide an idea about how nucleosome remodeling can be regulated during long-term memory formation and contributes to the permanent storage of associative fear memory in the lateral amygdala, which is relevant to fear and anxiety-related mental disorders. Copyright © 2017 the authors 0270-6474/17/373686-12$15.00/0.

A memristor-based nonvolatile latch circuit

NASA Astrophysics Data System (ADS)

Robinett, Warren; Pickett, Matthew; Borghetti, Julien; Xia, Qiangfei; Snider, Gregory S.; Medeiros-Ribeiro, Gilberto; Williams, R. Stanley

2010-06-01

Memristive devices, which exhibit a dynamical conductance state that depends on the excitation history, can be used as nonvolatile memory elements by storing information as different conductance states. We describe the implementation of a nonvolatile synchronous flip-flop circuit that uses a nanoscale memristive device as the nonvolatile memory element. Controlled testing of the circuit demonstrated successful state storage and restoration, with an error rate of 0.1%, during 1000 power loss events. These results indicate that integration of digital logic devices and memristors could open the way for nonvolatile computation with applications in small platforms that rely on intermittent power sources. This demonstrated feasibility of tight integration of memristors with CMOS (complementary metal-oxide-semiconductor) circuitry challenges the traditional memory hierarchy, in which nonvolatile memory is only available as a large, slow, monolithic block at the bottom of the hierarchy. In contrast, the nonvolatile, memristor-based memory cell can be fast, fine-grained and small, and is compatible with conventional CMOS electronics. This threatens to upset the traditional memory hierarchy, and may open up new architectural possibilities beyond it.

Memory for light as a quantum process.

PubMed

Lobino, M; Kupchak, C; Figueroa, E; Lvovsky, A I

2009-05-22

We report complete characterization of an optical memory based on electromagnetically induced transparency. We recover the superoperator associated with the memory, under two different working conditions, by means of a quantum process tomography technique that involves storage of coherent states and their characterization upon retrieval. In this way, we can predict the quantum state retrieved from the memory for any input, for example, the squeezed vacuum or the Fock state. We employ the acquired superoperator to verify the nonclassicality benchmark for the storage of a Gaussian distributed set of coherent states.

A Specific Role for Hippocampal Mossy Fiber's Zinc in Rapid Storage of Emotional Memories

ERIC Educational Resources Information Center

Ceccom, Johnatan; Halley, Hélène; Daumas, Stéphanie; Lassalle, Jean Michel

2014-01-01

We investigated the specific role of zinc present in large amounts in the synaptic vesicles of mossy fibers and coreleased with glutamate in the CA3 region. In previous studies, we have shown that blockade of zinc after release has no effect on the consolidation of spatial learning, while zinc is required for the consolidation of contextual fear…

Quantum teleportation between remote atomic-ensemble quantum memories.

PubMed

Bao, Xiao-Hui; Xu, Xiao-Fan; Li, Che-Ming; Yuan, Zhen-Sheng; Lu, Chao-Yang; Pan, Jian-Wei

2012-12-11

Quantum teleportation and quantum memory are two crucial elements for large-scale quantum networks. With the help of prior distributed entanglement as a "quantum channel," quantum teleportation provides an intriguing means to faithfully transfer quantum states among distant locations without actual transmission of the physical carriers [Bennett CH, et al. (1993) Phys Rev Lett 70(13):1895-1899]. Quantum memory enables controlled storage and retrieval of fast-flying photonic quantum bits with stationary matter systems, which is essential to achieve the scalability required for large-scale quantum networks. Combining these two capabilities, here we realize quantum teleportation between two remote atomic-ensemble quantum memory nodes, each composed of ∼10(8) rubidium atoms and connected by a 150-m optical fiber. The spin wave state of one atomic ensemble is mapped to a propagating photon and subjected to Bell state measurements with another single photon that is entangled with the spin wave state of the other ensemble. Two-photon detection events herald the success of teleportation with an average fidelity of 88(7)%. Besides its fundamental interest as a teleportation between two remote macroscopic objects, our technique may be useful for quantum information transfer between different nodes in quantum networks and distributed quantum computing.

Research on Multi - Person Parallel Modeling Method Based on Integrated Model Persistent Storage

NASA Astrophysics Data System (ADS)

Qu, MingCheng; Wu, XiangHu; Tao, YongChao; Liu, Ying

2018-03-01

This paper mainly studies the multi-person parallel modeling method based on the integrated model persistence storage. The integrated model refers to a set of MDDT modeling graphics system, which can carry out multi-angle, multi-level and multi-stage description of aerospace general embedded software. Persistent storage refers to converting the data model in memory into a storage model and converting the storage model into a data model in memory, where the data model refers to the object model and the storage model is a binary stream. And multi-person parallel modeling refers to the need for multi-person collaboration, the role of separation, and even real-time remote synchronization modeling.

Opiate-associated contextual memory formation and retrieval are differentially modulated by dopamine D1 and D2 signaling in hippocampal-prefrontal connectivity.

PubMed

Wang, Yunpeng; Zhang, Hongying; Cui, Jingjing; Zhang, Jing; Yin, Fangyuan; Guo, Hao; Lai, Jianghua; Xing, Bo

2018-04-17

Contextual memory driven by abused drugs such as opiates has a central role in maintenance and relapse of drug-taking behaviors. Although dopamine (DA) signaling favors memory storage and retrieval via regulation of hippocampal-prefrontal connectivity, its role in modulating opiate-associated contextual memory is largely unknown. Here, we report roles of DA signaling within the hippocampal-prefrontal circuit for opiate-related memories. Combining-conditioned place preference (CPP) with molecular analyses, we investigated the DA D1 receptor (D1R) and extracellular signal-regulated kinase (ERK)-cAMP-response element binding protein (CREB) signaling, as well as DA D2 receptor (D2R) and protein kinase B (PKB or Akt)/glycogen synthase kinase 3 (GSK3) signaling in the ventral hippocampus (vHip) and medial prefrontal cortex (mPFC) during the formation of opiate-related associative memories. Morphine-CPP acquisition increased the activity of the D1R-ERK-CREB pathway in both the vHip and mPFC. Morphine-CPP reinstatement was associated with the D2R-mediated hyperactive GSK3 via Akt inhibition in the vHip and PFC. Furthermore, integrated D1R-ERK-CREB and D2R-Akt-GSK3 pathways in the vHip-mPFC circuit are required for the acquisition and retrieval of the morphine contextual memory, respectively. Moreover, blockage of D1R or D2R signaling could alleviate normal Hip-dependent spatial memory. These results suggest that D1R and D2R signaling are differentially involved in the acquisition and retrieval of morphine contextual memory, and DA signaling in the vHip-mPFC connection contributes to morphine-associated and normal memory, largely depending on opiate exposure states.

Vascular surgical data registries for small computers.

PubMed

Kaufman, J L; Rosenberg, N

1984-08-01

Recent designs for computer-based vascular surgical registries and clinical data bases have employed large centralized systems with formal programming and mass storage. Small computers, of the types created for office use or for word processing, now contain sufficient speed and memory storage capacity to allow construction of decentralized office-based registries. Using a standardized dictionary of terms and a method of data organization adapted to word processing, we have created a new vascular surgery data registry, "VASREG." Data files are organized without programming, and a limited number of powerful logical statements in English are used for sorting. The capacity is 25,000 records with current inexpensive memory technology. VASREG is adaptable to computers made by a variety of manufacturers, and interface programs are available for conversion of the word processor formated registry data into forms suitable for analysis by programs written in a standard programming language. This is a low-cost clinical data registry available to any physician. With a standardized dictionary, preparation of regional and national statistical summaries may be facilitated.

Light storage in a cold atomic ensemble with a high optical depth

NASA Astrophysics Data System (ADS)

Park, Kwang-Kyoon; Chough, Young-Tak; Kim, Yoon-Ho

2017-06-01

A quantum memory with a high storage efficiency and a long coherence time is an essential element in quantum information applications. Here, we report our recent development of an optical quantum memory with a rubidium-87 cold atom ensemble. By increasing the optical depth of the medium, we have achieved a storage efficiency of 65% and a coherence time of 51 μs for a weak laser pulse. The result of a numerical analysis based on the Maxwell-Bloch equations agrees well with the experimental results. Our result paves the way toward an efficient optical quantum memory and may find applications in photonic quantum information processing.

David Adler Lectureship Award in the Field of Materials Physics: Racetrack Memory - a high-performance, storage class memory using magnetic domain-walls manipulated by current

NASA Astrophysics Data System (ADS)

Parkin, Stuart

2012-02-01

Racetrack Memory is a novel high-performance, non-volatile storage-class memory in which magnetic domains are used to store information in a ``magnetic racetrack'' [1]. The magnetic racetrack promises a solid state memory with storage capacities and cost rivaling that of magnetic disk drives but with much improved performance and reliability: a ``hard disk on a chip''. The magnetic racetrack is comprised of a magnetic nanowire in which a series of magnetic domain walls are shifted to and fro along the wire using nanosecond-long pulses of spin polarized current [2]. We have demonstrated the underlying physics that makes Racetrack Memory possible [3,4] and all the basic functions - creation, and manipulation of a train of domain walls and their detection. The physics underlying the current induced dynamics of domain walls will also be discussed. In particular, we show that the domain walls respond as if they have mass, leading to significant inertial driven motion of the domain walls over long times after the current pulses are switched off [3]. We also demonstrate that in perpendicularly magnetized nanowires there are two independent current driving mechanisms: one derived from bulk spin-dependent scattering that drives the domain walls in the direction of electron flow, and a second interfacial mechanism that can drive the domain walls either along or against the electron flow, depending on subtle changes in the nanowire structure. Finally, we demonstrate thermally induced spin currents are large enough that they can be used to manipulate domain walls. [4pt] [1] S.S.P. Parkin, US Patent 6,834,005 (2004); S.S.P. Parkin et al., Science 320, 190 (2008); S.S.P. Parkin, Scientific American (June 2009). [0pt] [2] M. Hayashi, L. Thomas, R. Moriya, C. Rettner and S.S.P. Parkin, Science 320, 209 (2008). [0pt] [3] L. Thomas, R. Moriya, C. Rettner and S.S.P. Parkin, Science 330, 1810 (2010). [0pt] [4] X. Jiang et al. Nat. Comm. 1:25 (2010) and Nano Lett. 11, 96 (2011).

Evolutionary Metal Oxide Clusters for Novel Applications: Toward High-Density Data Storage in Nonvolatile Memories.

PubMed

Chen, Xiaoli; Zhou, Ye; Roy, Vellaisamy A L; Han, Su-Ting

2018-01-01

Because of current fabrication limitations, miniaturizing nonvolatile memory devices for managing the explosive increase in big data is challenging. Molecular memories constitute a promising candidate for next-generation memories because their properties can be readily modulated through chemical synthesis. Moreover, these memories can be fabricated through mild solution processing, which can be easily scaled up. Among the various materials, polyoxometalate (POM) molecules have attracted considerable attention for use as novel data-storage nodes for nonvolatile memories. Here, an overview of recent advances in the development of POMs for nonvolatile memories is presented. The general background knowledge of the structure and property diversity of POMs is also summarized. Finally, the challenges and perspectives in the application of POMs in memories are discussed. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Application of phase-change materials in memory taxonomy.

PubMed

Wang, Lei; Tu, Liang; Wen, Jing

2017-01-01

Phase-change materials are suitable for data storage because they exhibit reversible transitions between crystalline and amorphous states that have distinguishable electrical and optical properties. Consequently, these materials find applications in diverse memory devices ranging from conventional optical discs to emerging nanophotonic devices. Current research efforts are mostly devoted to phase-change random access memory, whereas the applications of phase-change materials in other types of memory devices are rarely reported. Here we review the physical principles of phase-change materials and devices aiming to help researchers understand the concept of phase-change memory. We classify phase-change memory devices into phase-change optical disc, phase-change scanning probe memory, phase-change random access memory, and phase-change nanophotonic device, according to their locations in memory hierarchy. For each device type we discuss the physical principles in conjunction with merits and weakness for data storage applications. We also outline state-of-the-art technologies and future prospects.

Two-dimensional molybdenum disulphide nanosheet-covered metal nanoparticle array as a floating gate in multi-functional flash memories

NASA Astrophysics Data System (ADS)

Han, Su-Ting; Zhou, Ye; Chen, Bo; Zhou, Li; Yan, Yan; Zhang, Hua; Roy, V. A. L.

2015-10-01

Semiconducting two-dimensional materials appear to be excellent candidates for non-volatile memory applications. However, the limited controllability of charge trapping behaviors and the lack of multi-bit storage studies in two-dimensional based memory devices require further improvement for realistic applications. Here, we report a flash memory consisting of metal NPs-molybdenum disulphide (MoS2) as a floating gate by introducing a metal nanoparticle (NP) (Ag, Au, Pt) monolayer underneath the MoS2 nanosheets. Controlled charge trapping and long data retention have been achieved in a metal (Ag, Au, Pt) NPs-MoS2 floating gate flash memory. This controlled charge trapping is hypothesized to be attributed to band bending and a built-in electric field ξbi between the interface of the metal NPs and MoS2. The metal NPs-MoS2 floating gate flash memories were further proven to be multi-bit memory storage devices possessing a 3-bit storage capability and a good retention capability up to 104 s. We anticipate that these findings would provide scientific insight for the development of novel memory devices utilizing an atomically thin two-dimensional lattice structure.Semiconducting two-dimensional materials appear to be excellent candidates for non-volatile memory applications. However, the limited controllability of charge trapping behaviors and the lack of multi-bit storage studies in two-dimensional based memory devices require further improvement for realistic applications. Here, we report a flash memory consisting of metal NPs-molybdenum disulphide (MoS2) as a floating gate by introducing a metal nanoparticle (NP) (Ag, Au, Pt) monolayer underneath the MoS2 nanosheets. Controlled charge trapping and long data retention have been achieved in a metal (Ag, Au, Pt) NPs-MoS2 floating gate flash memory. This controlled charge trapping is hypothesized to be attributed to band bending and a built-in electric field ξbi between the interface of the metal NPs and MoS2. The metal NPs-MoS2 floating gate flash memories were further proven to be multi-bit memory storage devices possessing a 3-bit storage capability and a good retention capability up to 104 s. We anticipate that these findings would provide scientific insight for the development of novel memory devices utilizing an atomically thin two-dimensional lattice structure. Electronic supplementary information (ESI) available: Energy-dispersive X-ray spectroscopy (EDS) spectra of the metal NPs, SEM image of MoS2 on Au NPs, erasing operations of the metal NPs-MoS2 memory device, transfer characteristics of the standard FET devices and Ag NP devices under programming operation, tapping-mode AFM height image of the fabricated MoS2 film for pristine MoS2 flash memory, gate signals used for programming the Au NPs-MoS2 and Pt NPs-MoS2 flash memories, and data levels recorded for 100 sequential cycles. See DOI: 10.1039/c5nr05054e

Retrieval and Sleep Both Counteract the Forgetting of Spatial Information

ERIC Educational Resources Information Center

Antony, James W.; Paller, Ken A.

2018-01-01

Repeatedly studying information is a good way to strengthen memory storage. Nevertheless, testing recall often produces superior long-term retention. Demonstrations of this testing effect, typically with verbal stimuli, have shown that repeated retrieval through testing reduces forgetting. Sleep also benefits memory storage, perhaps through…

The role of inhibition for working memory processes: ERP evidence from a short-term storage task.

PubMed

Getzmann, Stephan; Wascher, Edmund; Schneider, Daniel

2018-05-01

Human working memory is the central unit for short-term storage of information. In addition to the selection and adequate storage of relevant information, the suppression of irrelevant stimuli from the environment seems to be of importance for working memory processes. To learn more about the interplay of information uptake and inhibition of irrelevant information, the present study used ERP measures and a short-term storage and retrieval task, in which pairs of either numbers or letters had to be compared. Random sequences of four stimuli (two numbers and two letters) were presented, with either the numbers or the letters being relevant for comparison. The analysis of ERPs to each of the four stimuli indicated more pronounced P2 and P3b amplitudes for relevant than irrelevant stimuli. In contrast, the N2 (reflecting inhibitory control) was only elicited by irrelevant stimuli. Moreover, the N2 amplitude of the second irrelevant stimulus was associated with behavioral performance, indicating the importance of inhibition of task-irrelevant stimuli for working memory processes. In sum, the findings demonstrate the role of cognitive control mechanisms for protecting relevant contents in working memory against irrelevant information. © 2017 Society for Psychophysiological Research.

Cognitive control components and speech symptoms in people with schizophrenia.

PubMed

Becker, Theresa M; Cicero, David C; Cowan, Nelson; Kerns, John G

2012-03-30

Previous schizophrenia research suggests poor cognitive control is associated with schizophrenia speech symptoms. However, cognitive control is a broad construct. Two important cognitive control components are poor goal maintenance and poor verbal working memory storage. In the current research, people with schizophrenia (n=45) performed three cognitive tasks that varied in their goal maintenance and verbal working memory storage demands. Speech symptoms were assessed using clinical rating scales, ratings of disorganized speech from typed transcripts, and self-reported disorganization. Overall, alogia was associated with both goal maintenance and verbal working memory tasks. Objectively rated disorganized speech was associated with poor goal maintenance and with a task that included both goal maintenance and verbal working memory storage demands. In contrast, self-reported disorganization was unrelated to either amount of objectively rated disorganized speech or to cognitive control task performance, instead being associated with negative mood symptoms. Overall, our results suggest that alogia is associated with both poor goal maintenance and poor verbal working memory storage and that disorganized speech is associated with poor goal maintenance. In addition, patients' own assessment of their disorganization is related to negative mood, but perhaps not to objective disorganized speech or to cognitive control task performance. Published by Elsevier Ireland Ltd.

Iconic Memory and Reading Performance in Nine-Year-Old Children

ERIC Educational Resources Information Center

Riding, R. J.; Pugh, J. C.

1977-01-01

The reading process incorporates three factors: images registered in visual sensory memory, semantic analysis in short-term memory, and long-term memory storage. The focus here is on the contribution of sensory memory to reading performance. (Author/RK)

3D Kirchhoff depth migration algorithm: A new scalable approach for parallelization on multicore CPU based cluster

NASA Astrophysics Data System (ADS)

Rastogi, Richa; Londhe, Ashutosh; Srivastava, Abhishek; Sirasala, Kirannmayi M.; Khonde, Kiran

2017-03-01

In this article, a new scalable 3D Kirchhoff depth migration algorithm is presented on state of the art multicore CPU based cluster. Parallelization of 3D Kirchhoff depth migration is challenging due to its high demand of compute time, memory, storage and I/O along with the need of their effective management. The most resource intensive modules of the algorithm are traveltime calculations and migration summation which exhibit an inherent trade off between compute time and other resources. The parallelization strategy of the algorithm largely depends on the storage of calculated traveltimes and its feeding mechanism to the migration process. The presented work is an extension of our previous work, wherein a 3D Kirchhoff depth migration application for multicore CPU based parallel system had been developed. Recently, we have worked on improving parallel performance of this application by re-designing the parallelization approach. The new algorithm is capable to efficiently migrate both prestack and poststack 3D data. It exhibits flexibility for migrating large number of traces within the available node memory and with minimal requirement of storage, I/O and inter-node communication. The resultant application is tested using 3D Overthrust data on PARAM Yuva II, which is a Xeon E5-2670 based multicore CPU cluster with 16 cores/node and 64 GB shared memory. Parallel performance of the algorithm is studied using different numerical experiments and the scalability results show striking improvement over its previous version. An impressive 49.05X speedup with 76.64% efficiency is achieved for 3D prestack data and 32.00X speedup with 50.00% efficiency for 3D poststack data, using 64 nodes. The results also demonstrate the effectiveness and robustness of the improved algorithm with high scalability and efficiency on a multicore CPU cluster.

The Sensory Components of High-Capacity Iconic Memory and Visual Working Memory

PubMed Central

Bradley, Claire; Pearson, Joel

2012-01-01

Early visual memory can be split into two primary components: a high-capacity, short-lived iconic memory followed by a limited-capacity visual working memory that can last many seconds. Whereas a large number of studies have investigated visual working memory for low-level sensory features, much research on iconic memory has used more “high-level” alphanumeric stimuli such as letters or numbers. These two forms of memory are typically examined separately, despite an intrinsic overlap in their characteristics. Here, we used a purely sensory paradigm to examine visual short-term memory for 10 homogeneous items of three different visual features (color, orientation and motion) across a range of durations from 0 to 6 s. We found that the amount of information stored in iconic memory is smaller for motion than for color or orientation. Performance declined exponentially with longer storage durations and reached chance levels after ∼2 s. Further experiments showed that performance for the 10 items at 1 s was contingent on unperturbed attentional resources. In addition, for orientation stimuli, performance was contingent on the location of stimuli in the visual field, especially for short cue delays. Overall, our results suggest a smooth transition between an automatic, high-capacity, feature-specific sensory-iconic memory, and an effortful “lower-capacity” visual working memory. PMID:23055993

Nicotine Modulates the Long-Lasting Storage of Fear Memory

ERIC Educational Resources Information Center

Lima, Ramon H.; Radiske, Andressa; Kohler, Cristiano A.; Gonzalez, Maria Carolina; Bevilaqua, Lia R.; Rossato, Janine I.; Medina, Jorge H.; Cammarota, Martin

2013-01-01

Late post-training activation of the ventral tegmental area (VTA)-hippocampus dopaminergic loop controls the entry of information into long-term memory (LTM). Nicotinic acetylcholine receptors (nAChR) modulate VTA function, but their involvement in LTM storage is unknown. Using pharmacological and behavioral tools, we found that…

Computer memory: the LLL experience. [Octopus computer network

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fletcher, J.G.

1976-02-01

Those aspects of Octopus computer network design are reviewed that relate to memory and storage. Emphasis is placed on the difficulties and problems that arise because of the limitations of present storage devices, and indications are made of the directions in which technological advance could be of most value. (auth)

Phonological Storage and Executive Function Deficits in Children with Mathematics Difficulties

ERIC Educational Resources Information Center

Peng, Peng; Congying, Sun; Beilei, Li; Sha, Tao

2012-01-01

Children with mathematics difficulties suffer from working memory deficits. This study investigated the deficit profile of phonological storage and executive functions in working memory among children with mathematics difficulties. Based on multiple instruments and two assessment points, 68 children were screened out of 805 fifth graders. Of these…

The Structure of Visuospatial Memory in Adulthood

ERIC Educational Resources Information Center

Mammarella, Irene C.; Borella, Erika; Pastore, Massimiliano; Pazzaglia, Francesca

2013-01-01

The present study aimed to investigate the structure of visuospatial memory in adulthood. Adults 40-89 years of age (n = 160) performed simple storage and complex visuospatial span tasks. Simple storage tasks were distinguished into three presentation formats: (i) visual, which involved maintaining shapes and textures; (ii) spatial-sequential,…

Feasibility study of molecular memory device based on DNA using methylation to store information

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jiang, Liming; Al-Dirini, Feras; Center for Neural Engineering

DNA, because of its robustness and dense information storage capability, has been proposed as a potential candidate for next-generation storage media. However, encoding information into the DNA sequence requires molecular synthesis technology, which to date is costly and prone to synthesis errors. Reading the DNA strand information is also complex. Ideally, DNA storage will provide methods for modifying stored information. Here, we conduct a feasibility study investigating the use of the DNA 5-methylcytosine (5mC) methylation state as a molecular memory to store information. We propose a new 1-bit memory device and study, based on the density functional theory and non-equilibriummore » Green's function method, the feasibility of electrically reading the information. Our results show that changes to methylation states lead to changes in the peak of negative differential resistance which can be used to interrogate memory state. Our work demonstrates a new memory concept based on methylation state which can be beneficial in the design of next generation DNA based molecular electronic memory devices.« less

Storage and executive processes in the frontal lobes.

PubMed

Smith, E E; Jonides, J

1999-03-12

The human frontal cortex helps mediate working memory, a system that is used for temporary storage and manipulation of information and that is involved in many higher cognitive functions. Working memory includes two components: short-term storage (on the order of seconds) and executive processes that operate on the contents of storage. Recently, these two components have been investigated in functional neuroimaging studies. Studies of storage indicate that different frontal regions are activated for different kinds of information: storage for verbal materials activates Broca's area and left-hemisphere supplementary and premotor areas; storage of spatial information activates the right-hemisphere premotor cortex; and storage of object information activates other areas of the prefrontal cortex. Two of the fundamental executive processes are selective attention and task management. Both processes activate the anterior cingulate and dorsolateral prefrontal cortex.

Emotionally enhanced memory for negatively arousing words: storage or retrieval advantage?

PubMed

Nadarevic, Lena

2017-12-01

People typically remember emotionally negative words better than neutral words. Two experiments are reported that investigate whether emotionally enhanced memory (EEM) for negatively arousing words is based on a storage or retrieval advantage. Participants studied non-word-word pairs that either involved negatively arousing or neutral target words. Memory for these target words was tested by means of a recognition test and a cued-recall test. Data were analysed with a multinomial model that allows the disentanglement of storage and retrieval processes in the present recognition-then-cued-recall paradigm. In both experiments the multinomial analyses revealed no storage differences between negatively arousing and neutral words but a clear retrieval advantage for negatively arousing words in the cued-recall test. These findings suggest that EEM for negatively arousing words is driven by associative processes.

Small Form Factor Information Storage Devices for Mobile Applications in Korea

NASA Astrophysics Data System (ADS)

Park, Young-Pil; Park, No-Cheol; Kim, Chul-Jin

Recently, the ubiquitous environment in which anybody can reach a lot of information data without any limitations on the place and time has become an important social issue. There are two basic requirements in the field of information storage devices which have to be satisfied; the first is the demand for the improvement of memory capacity to manage the increased data capacity in personal and official purposes. The second is the demand for new development of information storage devices small enough to be applied to mobile multimedia digital electronics, including digital camera, PDA and mobile phones. To summarize, for the sake of mobile applications, it is necessary to develop information storage devices which have simultaneously a large capacity and a small size. Korea possesses the necessary infrastructure for developing such small sized information storage devices. It has a good digital market, major digital companies, and various research institutes. Nowadays, many companies and research institutes including university cooperate together in the research on small sized information storage devices. Thus, it is expected that small form factor optical disk drives will be commercialized in the very near future in Korea.

Protecting solid-state spins from a strongly coupled environment

NASA Astrophysics Data System (ADS)

Chen, Mo; Calvin Sun, Won Kyu; Saha, Kasturi; Jaskula, Jean-Christophe; Cappellaro, Paola

2018-06-01

Quantum memories are critical for solid-state quantum computing devices and a good quantum memory requires both long storage time and fast read/write operations. A promising system is the nitrogen-vacancy (NV) center in diamond, where the NV electronic spin serves as the computing qubit and a nearby nuclear spin as the memory qubit. Previous works used remote, weakly coupled 13C nuclear spins, trading read/write speed for long storage time. Here we focus instead on the intrinsic strongly coupled 14N nuclear spin. We first quantitatively understand its decoherence mechanism, identifying as its source the electronic spin that acts as a quantum fluctuator. We then propose a scheme to protect the quantum memory from the fluctuating noise by applying dynamical decoupling on the environment itself. We demonstrate a factor of 3 enhancement of the storage time in a proof-of-principle experiment, showing the potential for a quantum memory that combines fast operation with long coherence time.

Neural Anatomy of Primary Visual Cortex Limits Visual Working Memory.

PubMed

Bergmann, Johanna; Genç, Erhan; Kohler, Axel; Singer, Wolf; Pearson, Joel

2016-01-01

Despite the immense processing power of the human brain, working memory storage is severely limited, and the neuroanatomical basis of these limitations has remained elusive. Here, we show that the stable storage limits of visual working memory for over 9 s are bound by the precise gray matter volume of primary visual cortex (V1), defined by fMRI retinotopic mapping. Individuals with a bigger V1 tended to have greater visual working memory storage. This relationship was present independently for both surface size and thickness of V1 but absent in V2, V3 and for non-visual working memory measures. Additional whole-brain analyses confirmed the specificity of the relationship to V1. Our findings indicate that the size of primary visual cortex plays a critical role in limiting what we can hold in mind, acting like a gatekeeper in constraining the richness of working mental function. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Holographic memories with encryption-selectable function

NASA Astrophysics Data System (ADS)

Su, Wei-Chia; Lee, Xuan-Hao

2006-03-01

Volume holographic storage has received increasing attention owing to its potential high storage capacity and access rate. In the meanwhile, encrypted holographic memory using random phase encoding technique is attractive for an optical community due to growing demand for protection of information. In this paper, encryption-selectable holographic storage algorithms in LiNbO 3 using angular multiplexing are proposed and demonstrated. Encryption-selectable holographic memory is an advance concept of security storage for content protection. It offers more flexibility to encrypt the data or not optionally during the recording processes. In our system design, the function of encryption and non-encryption storage is switched by a random phase pattern and a uniform phase pattern. Based on a 90-degree geometry, the input patterns including the encryption and non-encryption storage are stored via angular multiplexing with reference plane waves at different incident angles. Image is encrypted optionally by sliding the ground glass into one of the recording waves or removing it away in each exposure. The ground glass is a key for encryption. Besides, it is also an important key available for authorized user to decrypt the encrypted information.

Multi-Level Bitmap Indexes for Flash Memory Storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Kesheng; Madduri, Kamesh; Canon, Shane

2010-07-23

Due to their low access latency, high read speed, and power-efficient operation, flash memory storage devices are rapidly emerging as an attractive alternative to traditional magnetic storage devices. However, tests show that the most efficient indexing methods are not able to take advantage of the flash memory storage devices. In this paper, we present a set of multi-level bitmap indexes that can effectively take advantage of flash storage devices. These indexing methods use coarsely binned indexes to answer queries approximately, and then use finely binned indexes to refine the answers. Our new methods read significantly lower volumes of data atmore » the expense of an increased disk access count, thus taking full advantage of the improved read speed and low access latency of flash devices. To demonstrate the advantage of these new indexes, we measure their performance on a number of storage systems using a standard data warehousing benchmark called the Set Query Benchmark. We observe that multi-level strategies on flash drives are up to 3 times faster than traditional indexing strategies on magnetic disk drives.« less

Memory timeline: Brain ERP C250 (not P300) is an early biomarker of short-term storage.

PubMed

Chapman, Robert M; Gardner, Margaret N; Mapstone, Mark; Dupree, Haley M; Antonsdottir, Inga M

2015-04-16

Brain event-related potentials (ERPs) offer a quantitative link between neurophysiological activity and cognitive performance. ERPs were measured while young adults performed a task that required storing a relevant stimulus in short-term memory. Using principal components analysis, ERP component C250 (maximum at 250 ms post-stimulus) was extracted from a set of ERPs that were separately averaged for various task conditions, including stimulus relevancy and stimulus sequence within a trial. C250 was more positive in response to task-specific stimuli that were successfully stored in short-term memory. This relationship between C250 and short-term memory storage of a stimulus was confirmed by a memory probe recall test where the behavioral recall of a stimulus was highly correlated with its C250 amplitude. ERP component P300 (and its subcomponents of P3a and P3b, which are commonly thought to represent memory operations) did not show a pattern of activation reflective of storing task-relevant stimuli. C250 precedes the P300, indicating that initial short-term memory storage may occur earlier than previously believed. Additionally, because C250 is so strongly predictive of a stimulus being stored in short-term memory, C250 may provide a strong index of early memory operations. Copyright © 2015 Elsevier B.V. All rights reserved.

Ultrasound Picture Archiving And Communication Systems

NASA Astrophysics Data System (ADS)

Koestner, Ken; Hottinger, C. F.

1982-01-01

The ideal ultrasonic image communication and storage system must be flexible in order to optimize speed and minimize storage requirements. Various ultrasonic imaging modalities are quite different in data volume and speed requirements. Static imaging, for example B-Scanning, involves acquisition of a large amount of data that is averaged or accumulated in a desired manner. The image is then frozen in image memory before transfer and storage. Images are commonly a 512 x 512 point array, each point 6 bits deep. Transfer of such an image over a serial line at 9600 baud would require about three minutes. Faster transfer times are possible; for example, we have developed a parallel image transfer system using direct memory access (DMA) that reduces the time to 16 seconds. Data in this format requires 256K bytes for storage. Data compression can be utilized to reduce these requirements. Real-time imaging has much more stringent requirements for speed and storage. The amount of actual data per frame in real-time imaging is reduced due to physical limitations on ultrasound. For example, 100 scan lines (480 points long, 6 bits deep) can be acquired during a frame at a 30 per second rate. In order to transmit and save this data at a real-time rate requires a transfer rate of 8.6 Megabaud. A real-time archiving system would be complicated by the necessity of specialized hardware to interpolate between scan lines and perform desirable greyscale manipulation on recall. Image archiving for cardiology and radiology would require data transfer at this high rate to preserve temporal (cardiology) and spatial (radiology) information.

Highly-Ordered 3D Vertical Resistive Switching Memory Arrays with Ultralow Power Consumption and Ultrahigh Density.

PubMed

Al-Haddad, Ahmed; Wang, Chengliang; Qi, Haoyuan; Grote, Fabian; Wen, Liaoyong; Bernhard, Jörg; Vellacheri, Ranjith; Tarish, Samar; Nabi, Ghulam; Kaiser, Ute; Lei, Yong

2016-09-07

Resistive switching random access memories (RRAM) have attracted great scientific and industrial attention for next generation data storage because of their advantages of nonvolatile properties, high density, low power consumption, fast writing/erasing speed, good endurance, and simple and small operation system. Here, by using a template-assisted technique, we demonstrate a three-dimensional highly ordered vertical RRAM device array with density as high as that of the nanopores of the template (10(8)-10(9) cm(-2)), which can also be fabricated in large area. The high crystallinity of the materials, the large contact area and the intimate semiconductor/electrode interface (3 nm interfacial layer) make the ultralow voltage operation (millivolt magnitude) and ultralow power consumption (picowatt) possible. Our procedure for fabrication of the nanodevice arrays in large area can be used for producing many other different materials and such three-dimensional electronic device arrays with the capability to adjust the device densities can be extended to other applications of the next generation nanodevice technology.

Development of a Handbook for Educators: Addressing Working Memory Capacity in Elementary Students

ERIC Educational Resources Information Center

Fernandez, Julie Marie

2013-01-01

Working Memory (WM) refers to a brain system that provides temporary storage and manipulation of the information necessary for complex cognitive tasks such as language comprehension, learning, and reasoning. WM also requires the simultaneous storage and processing of information. WM is directly related to academic performance in the classroom.…

Kagan Structures, Processing, and Excellence in College Teaching

ERIC Educational Resources Information Center

Kagan, Spencer

2014-01-01

Frequent student processing of lecture content (1) clears working memory, (2) increases long-term memory storage, (3) produces retrograde memory enhancement, (4) creates episodic memories, (5) increases alertness, and (6) activates many brain structures. These outcomes increase comprehension of and memory for content. Many professors now…

Synaptic clustering within dendrites: an emerging theory of memory formation

PubMed Central

Kastellakis, George; Cai, Denise J.; Mednick, Sara C.; Silva, Alcino J.; Poirazi, Panayiota

2015-01-01

It is generally accepted that complex memories are stored in distributed representations throughout the brain, however the mechanisms underlying these representations are not understood. Here, we review recent findings regarding the subcellular mechanisms implicated in memory formation, which provide evidence for a dendrite-centered theory of memory. Plasticity-related phenomena which affect synaptic properties, such as synaptic tagging and capture, synaptic clustering, branch strength potentiation and spinogenesis provide the foundation for a model of memory storage that relies heavily on processes operating at the dendrite level. The emerging picture suggests that clusters of functionally related synapses may serve as key computational and memory storage units in the brain. We discuss both experimental evidence and theoretical models that support this hypothesis and explore its advantages for neuronal function. PMID:25576663

Fragile visual short-term memory is an object-based and location-specific store.

PubMed

Pinto, Yaïr; Sligte, Ilja G; Shapiro, Kimron L; Lamme, Victor A F

2013-08-01

Fragile visual short-term memory (FM) is a recently discovered form of visual short-term memory. Evidence suggests that it provides rich and high-capacity storage, like iconic memory, yet it exists, without interference, almost as long as visual working memory. In the present study, we sought to unveil the functional underpinnings of this memory storage. We found that FM is only completely erased when the new visual scene appears at the same location and consists of the same objects as the to-be-recalled information. This result has two important implications: First, it shows that FM is an object- and location-specific store, and second, it suggests that FM might be used in everyday life when the presentation of visual information is appropriately designed.

Nonvolatile memory with Co-SiO2 core-shell nanocrystals as charge storage nodes in floating gate

NASA Astrophysics Data System (ADS)

Liu, Hai; Ferrer, Domingo A.; Ferdousi, Fahmida; Banerjee, Sanjay K.

2009-11-01

In this letter, we reported nanocrystal floating gate memory with Co-SiO2 core-shell nanocrystal charge storage nodes. By using a water-in-oil microemulsion scheme, Co-SiO2 core-shell nanocrystals were synthesized and closely packed to achieve high density matrix in the floating gate without aggregation. The insulator shell also can help to increase the thermal stability of the nanocrystal metal core during the fabrication process to improve memory performance.

Nonlinear machine learning and design of reconfigurable digital colloids.

PubMed

Long, Andrew W; Phillips, Carolyn L; Jankowksi, Eric; Ferguson, Andrew L

2016-09-14

Digital colloids, a cluster of freely rotating "halo" particles tethered to the surface of a central particle, were recently proposed as ultra-high density memory elements for information storage. Rational design of these digital colloids for memory storage applications requires a quantitative understanding of the thermodynamic and kinetic stability of the configurational states within which information is stored. We apply nonlinear machine learning to Brownian dynamics simulations of these digital colloids to extract the low-dimensional intrinsic manifold governing digital colloid morphology, thermodynamics, and kinetics. By modulating the relative size ratio between halo particles and central particles, we investigate the size-dependent configurational stability and transition kinetics for the 2-state tetrahedral (N = 4) and 30-state octahedral (N = 6) digital colloids. We demonstrate the use of this framework to guide the rational design of a memory storage element to hold a block of text that trades off the competing design criteria of memory addressability and volatility.

Nonvolatile memory with graphene oxide as a charge storage node in nanowire field-effect transistors

NASA Astrophysics Data System (ADS)

Baek, David J.; Seol, Myeong-Lok; Choi, Sung-Jin; Moon, Dong-Il; Choi, Yang-Kyu

2012-02-01

Through the structural modification of a three-dimensional silicon nanowire field-effect transistor, i.e., a double-gate FinFET, a structural platform was developed which allowed for us to utilize graphene oxide (GO) as a charge trapping layer in a nonvolatile memory device. By creating a nanogap between the gate and the channel, GO was embedded after the complete device fabrication. By applying a proper gate voltage, charge trapping, and de-trapping within the GO was enabled and resulted in large threshold voltage shifts. The employment of GO with FinFET in our work suggests that graphitic materials can potentially play a significant role for future nanoelectronic applications.

At the intersection of attention and memory: the mechanistic role of the posterior parietal lobe in working memory

PubMed Central

Berryhill, Marian E.; Chein, Jason; Olson, Ingrid R.

2011-01-01

Portions of the posterior parietal cortex (PPC) play a role in working memory (WM) yet the precise mechanistic function of this region remains poorly understood. The pure storage hypothesis proposes that this region functions as a short-lived modality-specific memory store. Alternatively, the internal attention hypothesis proposes that the PPC functions as an attention-based storage and refreshing mechanism deployable as an alternative to material-specific rehearsal. These models were tested in patients with bilateral PPC lesions. Our findings discount the pure storage hypothesis because variables indexing storage capacity and longevity were not disproportionately affected by PPC damage. Instead, our data support the internal attention account by showing that (a) normal participants tend to use a rehearsal-based WM maintenance strategy for recall tasks but not for recognition tasks; (b) patients with PPC lesions performed normally on WM tasks that relied on material-specific rehearsal strategies but poorly on WM tasks that relied on attention-based maintenance strategies and patient strategy usage could be shifted by task or instructions; (c) patients’ memory deficits extended into the long-term domain. These findings suggest that the PPC maintains or shifts internal attention among the representations of items in WM. PMID:21345344

At the intersection of attention and memory: the mechanistic role of the posterior parietal lobe in working memory.

PubMed

Berryhill, Marian E; Chein, Jason; Olson, Ingrid R

2011-04-01

Portions of the posterior parietal cortex (PPC) play a role in working memory (WM) yet the precise mechanistic function of this region remains poorly understood. The pure storage hypothesis proposes that this region functions as a short-lived modality-specific memory store. Alternatively, the internal attention hypothesis proposes that the PPC functions as an attention-based storage and refreshing mechanism deployable as an alternative to material-specific rehearsal. These models were tested in patients with bilateral PPC lesions. Our findings discount the pure storage hypothesis because variables indexing storage capacity and longevity were not disproportionately affected by PPC damage. Instead, our data support the internal attention account by showing that (a) normal participants tend to use a rehearsal-based WM maintenance strategy for recall tasks but not for recognition tasks; (b) patients with PPC lesions performed normally on WM tasks that relied on material-specific rehearsal strategies but poorly on WM tasks that relied on attention-based maintenance strategies and patient strategy usage could be shifted by task or instructions; (c) patients' memory deficits extended into the long-term domain. These findings suggest that the PPC maintains or shifts internal attention among the representations of items in WM. Copyright © 2011 Elsevier Ltd. All rights reserved.

The generality of working memory capacity: a latent-variable approach to verbal and visuospatial memory span and reasoning.

PubMed

Kane, Michael J; Hambrick, David Z; Tuholski, Stephen W; Wilhelm, Oliver; Payne, Tabitha W; Engle, Randall W

2004-06-01

A latent-variable study examined whether verbal and visuospatial working memory (WM) capacity measures reflect a primarily domain-general construct by testing 236 participants in 3 span tests each of verbal WM. visuospatial WM, verbal short-term memory (STM), and visuospatial STM. as well as in tests of verbal and spatial reasoning and general fluid intelligence (Gf). Confirmatory' factor analyses and structural equation models indicated that the WM tasks largely reflected a domain-general factor, whereas STM tasks, based on the same stimuli as the WM tasks, were much more domain specific. The WM construct was a strong predictor of Gf and a weaker predictor of domain-specific reasoning, and the reverse was true for the STM construct. The findings support a domain-general view of WM capacity, in which executive-attention processes drive the broad predictive utility of WM span measures, and domain-specific storage and rehearsal processes relate more strongly to domain-specific aspects of complex cognition. ((c) 2004 APA, all rights reserved)

Integrated information storage and transfer with a coherent magnetic device

PubMed Central

Jia, Ning; Banchi, Leonardo; Bayat, Abolfazl; Dong, Guangjiong; Bose, Sougato

2015-01-01

Quantum systems are inherently dissipation-less, making them excellent candidates even for classical information processing. We propose to use an array of large-spin quantum magnets for realizing a device which has two modes of operation: memory and data-bus. While the weakly interacting low-energy levels are used as memory to store classical information (bits), the high-energy levels strongly interact with neighboring magnets and mediate the spatial movement of information through quantum dynamics. Despite the fact that memory and data-bus require different features, which are usually prerogative of different physical systems – well isolation for the memory cells, and strong interactions for the transmission – our proposal avoids the notorious complexity of hybrid structures. The proposed mechanism can be realized with different setups. We specifically show that molecular magnets, as the most promising technology, can implement hundreds of operations within their coherence time, while adatoms on surfaces probed by a scanning tunneling microscope is a future possibility. PMID:26347152

Frequency and bandwidth conversion of single photons in a room-temperature diamond quantum memory

PubMed Central

Fisher, Kent A. G.; England, Duncan G.; MacLean, Jean-Philippe W.; Bustard, Philip J.; Resch, Kevin J.; Sussman, Benjamin J.

2016-01-01

The spectral manipulation of photons is essential for linking components in a quantum network. Large frequency shifts are needed for conversion between optical and telecommunication frequencies, while smaller shifts are useful for frequency-multiplexing quantum systems, in the same way that wavelength division multiplexing is used in classical communications. Here we demonstrate frequency and bandwidth conversion of single photons in a room-temperature diamond quantum memory. Heralded 723.5 nm photons, with 4.1 nm bandwidth, are stored as optical phonons in the diamond via a Raman transition. Upon retrieval from the diamond memory, the spectral shape of the photons is determined by a tunable read pulse through the reverse Raman transition. We report central frequency tunability over 4.2 times the input bandwidth, and bandwidth modulation between 0.5 and 1.9 times the input bandwidth. Our results demonstrate the potential for diamond, and Raman memories in general, as an integrated platform for photon storage and spectral conversion. PMID:27045988

The scope and control of attention as separate aspects of working memory.

PubMed

Shipstead, Zach; Redick, Thomas S; Hicks, Kenny L; Engle, Randall W

2012-01-01

The present study examines two varieties of working memory (WM) capacity task: visual arrays (i.e., a measure of the amount of information that can be maintained in working memory) and complex span (i.e., a task that taps WM-related attentional control). Using previously collected data sets we employ confirmatory factor analysis to demonstrate that visual arrays and complex span tasks load on separate, but correlated, factors. A subsequent series of structural equation models and regression analyses demonstrate that these factors contribute both common and unique variance to the prediction of general fluid intelligence (Gf). However, while visual arrays does contribute uniquely to higher cognition, its overall correlation to Gf is largely mediated by variance associated with the complex span factor. Thus we argue that visual arrays performance is not strictly driven by a limited-capacity storage system (e.g., the focus of attention; Cowan, 2001), but may also rely on control processes such as selective attention and controlled memory search.

Frequency and bandwidth conversion of single photons in a room-temperature diamond quantum memory.

PubMed

Fisher, Kent A G; England, Duncan G; MacLean, Jean-Philippe W; Bustard, Philip J; Resch, Kevin J; Sussman, Benjamin J

2016-04-05

The spectral manipulation of photons is essential for linking components in a quantum network. Large frequency shifts are needed for conversion between optical and telecommunication frequencies, while smaller shifts are useful for frequency-multiplexing quantum systems, in the same way that wavelength division multiplexing is used in classical communications. Here we demonstrate frequency and bandwidth conversion of single photons in a room-temperature diamond quantum memory. Heralded 723.5 nm photons, with 4.1 nm bandwidth, are stored as optical phonons in the diamond via a Raman transition. Upon retrieval from the diamond memory, the spectral shape of the photons is determined by a tunable read pulse through the reverse Raman transition. We report central frequency tunability over 4.2 times the input bandwidth, and bandwidth modulation between 0.5 and 1.9 times the input bandwidth. Our results demonstrate the potential for diamond, and Raman memories in general, as an integrated platform for photon storage and spectral conversion.

Two-stage optical recording: photoinduced birefringence and surface-mediated bits storage in bisazo-containing copolymers towards ultrahigh data memory.

PubMed

Hu, Yanlei; Wu, Dong; Li, Jiawen; Huang, Wenhao; Chu, Jiaru

2016-10-03

Ultrahigh density data storage is in high demand in the current age of big data and thus motivates many innovative storage technologies. Femtosecond laser induced multi-dimensional optical data storage is an appealing method to fulfill the demand of ultrahigh storage capacity. Here we report a femtosecond laser induced two-stage optical storage in bisazobenzene copolymer films by manipulating the recording energies. Different mechanisms can be selected for specified memory use: two-photon isomerization (TPI) and laser induced surface deformation. Giant birefringence can be generated by TPI and brings about high signal-to-noise ratio (>20 dB) multi-dimensional reversible storage. Polarization-dependent surface deformation arises when increasing the recording energy, which not only facilitates the multi-level storage by black bits (dots), but also enhances the bits' readout signal and storing stability. This facile bits recording method, which enables completely different recording mechanisms in an identical storage medium, paves the way for sustainable big data storage.

Retrograde amnesia in patients with diencephalic, temporal lobe or frontal lesions.

PubMed

Kopelman, M D; Stanhope, N; Kingsley, D

1999-07-01

Patients with focal diencephalic, temporal lobe, or frontal lobe lesions were examined on various measures of remote memory. Korsakoff patients showed a severe impairment with a characteristic 'temporal gradient', whereas two patients with focal diencephalic damage (and anterograde amnesia) were virtually unimpaired on remote memory measures. Patients with frontal lobe pathology were severely impaired in the recall of autobiographical incidents and famous news events. Patients with temporal lobe pathology showed severe impairment but a relatively 'flat' temporal gradient, largely attributable to herpes encephalitis patients. From recognition and cued recall tasks, it is argued that there is an important retrieval component to the remote memory deficit across all the lesion groups. In general, the pattern of performance by the frontal lobe and temporal lobe groups was closely similar, and there was no evidence of any major access/storage difference between them. However, laterality comparisons across these groups indicated that the right temporal and frontal lobe regions may make a greater contribution to the retrieval of past episodic (incident and event) memories, whereas the left temporal region is more closely involved in the lexical-semantic labelling of remote memories.

Avalanche atomic switching in strain engineered Sb2Te3-GeTe interfacial phase-change memory cells

NASA Astrophysics Data System (ADS)

Zhou, Xilin; Behera, Jitendra K.; Lv, Shilong; Wu, Liangcai; Song, Zhitang; Simpson, Robert E.

2017-09-01

By confining phase transitions to the nanoscale interface between two different crystals, interfacial phase change memory heterostructures represent the state of the art for energy efficient data storage. We present the effect of strain engineering on the electrical switching performance of the {{Sb}}2{{Te}}3-GeTe superlattice van der Waals devices. Multiple Ge atoms switching through a two-dimensional Te layer reduces the activation barrier for further atoms to switch; an effect that can be enhanced by biaxial strain. The out-of-plane phonon mode of the GeTe crystal remains active in the superlattice heterostructures. The large in-plane biaxial strain imposed by the {{Sb}}2{{Te}}3 layers on the GeTe layers substantially improves the switching speed, reset energy, and cyclability of the superlattice memory devices. Moreover, carefully controlling residual stress in the layers of {{Sb}}2{{Te}}3-GeTe interfacial phase change memories provides a new degree of freedom to design the properties of functional superlattice structures for memory and photonics applications.

Application of phase-change materials in memory taxonomy

PubMed Central

Wang, Lei; Tu, Liang; Wen, Jing

2017-01-01

Abstract Phase-change materials are suitable for data storage because they exhibit reversible transitions between crystalline and amorphous states that have distinguishable electrical and optical properties. Consequently, these materials find applications in diverse memory devices ranging from conventional optical discs to emerging nanophotonic devices. Current research efforts are mostly devoted to phase-change random access memory, whereas the applications of phase-change materials in other types of memory devices are rarely reported. Here we review the physical principles of phase-change materials and devices aiming to help researchers understand the concept of phase-change memory. We classify phase-change memory devices into phase-change optical disc, phase-change scanning probe memory, phase-change random access memory, and phase-change nanophotonic device, according to their locations in memory hierarchy. For each device type we discuss the physical principles in conjunction with merits and weakness for data storage applications. We also outline state-of-the-art technologies and future prospects. PMID:28740557

Kanerva's sparse distributed memory with multiple hamming thresholds

NASA Technical Reports Server (NTRS)

Pohja, Seppo; Kaski, Kimmo

1992-01-01

If the stored input patterns of Kanerva's Sparse Distributed Memory (SDM) are highly correlated, utilization of the storage capacity is very low compared to the case of uniformly distributed random input patterns. We consider a variation of SDM that has a better storage capacity utilization for correlated input patterns. This approach uses a separate selection threshold for each physical storage address or hard location. The selection of the hard locations for reading or writing can be done in parallel of which SDM implementations can benefit.

Storage and retrieval of large digital images

DOEpatents

Bradley, J.N.

1998-01-20

Image compression and viewing are implemented with (1) a method for performing DWT-based compression on a large digital image with a computer system possessing a two-level system of memory and (2) a method for selectively viewing areas of the image from its compressed representation at multiple resolutions and, if desired, in a client-server environment. The compression of a large digital image I(x,y) is accomplished by first defining a plurality of discrete tile image data subsets T{sub ij}(x,y) that, upon superposition, form the complete set of image data I(x,y). A seamless wavelet-based compression process is effected on I(x,y) that is comprised of successively inputting the tiles T{sub ij}(x,y) in a selected sequence to a DWT routine, and storing the resulting DWT coefficients in a first primary memory. These coefficients are periodically compressed and transferred to a secondary memory to maintain sufficient memory in the primary memory for data processing. The sequence of DWT operations on the tiles T{sub ij}(x,y) effectively calculates a seamless DWT of I(x,y). Data retrieval consists of specifying a resolution and a region of I(x,y) for display. The subset of stored DWT coefficients corresponding to each requested scene is determined and then decompressed for input to an inverse DWT, the output of which forms the image display. The repeated process whereby image views are specified may take the form an interaction with a computer pointing device on an image display from a previous retrieval. 6 figs.

Storage and retrieval of large digital images

DOEpatents

Bradley, Jonathan N.

1998-01-01

Image compression and viewing are implemented with (1) a method for performing DWT-based compression on a large digital image with a computer system possessing a two-level system of memory and (2) a method for selectively viewing areas of the image from its compressed representation at multiple resolutions and, if desired, in a client-server environment. The compression of a large digital image I(x,y) is accomplished by first defining a plurality of discrete tile image data subsets T.sub.ij (x,y) that, upon superposition, form the complete set of image data I(x,y). A seamless wavelet-based compression process is effected on I(x,y) that is comprised of successively inputting the tiles T.sub.ij (x,y) in a selected sequence to a DWT routine, and storing the resulting DWT coefficients in a first primary memory. These coefficients are periodically compressed and transferred to a secondary memory to maintain sufficient memory in the primary memory for data processing. The sequence of DWT operations on the tiles T.sub.ij (x,y) effectively calculates a seamless DWT of I(x,y). Data retrieval consists of specifying a resolution and a region of I(x,y) for display. The subset of stored DWT coefficients corresponding to each requested scene is determined and then decompressed for input to an inverse DWT, the output of which forms the image display. The repeated process whereby image views are specified may take the form an interaction with a computer pointing device on an image display from a previous retrieval.

A new parallel-vector finite element analysis software on distributed-memory computers

NASA Technical Reports Server (NTRS)

Qin, Jiangning; Nguyen, Duc T.

1993-01-01

A new parallel-vector finite element analysis software package MPFEA (Massively Parallel-vector Finite Element Analysis) is developed for large-scale structural analysis on massively parallel computers with distributed-memory. MPFEA is designed for parallel generation and assembly of the global finite element stiffness matrices as well as parallel solution of the simultaneous linear equations, since these are often the major time-consuming parts of a finite element analysis. Block-skyline storage scheme along with vector-unrolling techniques are used to enhance the vector performance. Communications among processors are carried out concurrently with arithmetic operations to reduce the total execution time. Numerical results on the Intel iPSC/860 computers (such as the Intel Gamma with 128 processors and the Intel Touchstone Delta with 512 processors) are presented, including an aircraft structure and some very large truss structures, to demonstrate the efficiency and accuracy of MPFEA.

A review of emerging non-volatile memory (NVM) technologies and applications

NASA Astrophysics Data System (ADS)

Chen, An

2016-11-01

This paper will review emerging non-volatile memory (NVM) technologies, with the focus on phase change memory (PCM), spin-transfer-torque random-access-memory (STTRAM), resistive random-access-memory (RRAM), and ferroelectric field-effect-transistor (FeFET) memory. These promising NVM devices are evaluated in terms of their advantages, challenges, and applications. Their performance is compared based on reported parameters of major industrial test chips. Memory selector devices and cell structures are discussed. Changing market trends toward low power (e.g., mobile, IoT) and data-centric applications create opportunities for emerging NVMs. High-performance and low-cost emerging NVMs may simplify memory hierarchy, introduce non-volatility in logic gates and circuits, reduce system power, and enable novel architectures. Storage-class memory (SCM) based on high-density NVMs could fill the performance and density gap between memory and storage. Some unique characteristics of emerging NVMs can be utilized for novel applications beyond the memory space, e.g., neuromorphic computing, hardware security, etc. In the beyond-CMOS era, emerging NVMs have the potential to fulfill more important functions and enable more efficient, intelligent, and secure computing systems.

Storage Media for Microcomputers.

ERIC Educational Resources Information Center

Trautman, Rodes

1983-01-01

Reviews computer storage devices designed to provide additional memory for microcomputers--chips, floppy disks, hard disks, optical disks--and describes how secondary storage is used (file transfer, formatting, ingredients of incompatibility); disk/controller/software triplet; magnetic tape backup; storage volatility; disk emulator; and…

Bubble memory module for spacecraft application

NASA Technical Reports Server (NTRS)

Hayes, P. J.; Looney, K. T.; Nichols, C. D.

1985-01-01

Bubble domain technology offers an all-solid-state alternative for data storage in onboard data systems. A versatile modular bubble memory concept was developed. The key module is the bubble memory module which contains all of the storage devices and circuitry for accessing these devices. This report documents the bubble memory module design and preliminary hardware designs aimed at memory module functional demonstration with available commercial bubble devices. The system architecture provides simultaneous operation of bubble devices to attain high data rates. Banks of bubble devices are accessed by a given bubble controller to minimize controller parts. A power strobing technique is discussed which could minimize the average system power dissipation. A fast initialization method using EEPROM (electrically erasable, programmable read-only memory) devices promotes fast access. Noise and crosstalk problems and implementations to minimize these are discussed. Flight memory systems which incorporate the concepts and techniques of this work could now be developed for applications.

Storage of features, conjunctions and objects in visual working memory.

PubMed

Vogel, E K; Woodman, G F; Luck, S J

2001-02-01

Working memory can be divided into separate subsystems for verbal and visual information. Although the verbal system has been well characterized, the storage capacity of visual working memory has not yet been established for simple features or for conjunctions of features. The authors demonstrate that it is possible to retain information about only 3-4 colors or orientations in visual working memory at one time. Observers are also able to retain both the color and the orientation of 3-4 objects, indicating that visual working memory stores integrated objects rather than individual features. Indeed, objects defined by a conjunction of four features can be retained in working memory just as well as single-feature objects, allowing many individual features to be retained when distributed across a small number of objects. Thus, the capacity of visual working memory must be understood in terms of integrated objects rather than individual features.

A wide bandwidth CCD buffer memory system

NASA Technical Reports Server (NTRS)

Siemens, K.; Wallace, R. W.; Robinson, C. R.

1978-01-01

A prototype system was implemented to demonstrate that CCD's can be applied advantageously to the problem of low power digital storage and particularly to the problem of interfacing widely varying data rates. CCD shift register memories (8K bit) were used to construct a feasibility model 128 K-bit buffer memory system. Serial data that can have rates between 150 kHz and 4.0 MHz can be stored in 4K-bit, randomly-accessible memory blocks. Peak power dissipation during a data transfer is less than 7 W, while idle power is approximately 5.4 W. The system features automatic data input synchronization with the recirculating CCD memory block start address. System expansion to accommodate parallel inputs or a greater number of memory blocks can be performed in a modular fashion. Since the control logic does not increase proportionally to increase in memory capacity, the power requirements per bit of storage can be reduced significantly in a larger system.

Design and realization of flash translation layer in tiny embedded system

NASA Astrophysics Data System (ADS)

Ren, Xiaoping; Sui, Chaoya; Luo, Zhenghua; Cao, Wenji

2018-05-01

We design a solution of tiny embedded device NAND Flash storage system on the basis of deeply studying the characteristics of widely used NAND Flash in the embedded devices in order to adapt to the development of intelligent interconnection trend and solve the storage problem of large data volume in tiny embedded system. The hierarchical structure and function purposes of the system are introduced. The design and realization of address mapping, error correction, bad block management, wear balance, garbage collection and other algorithms in flash memory transformation layer are described in details. NAND Flash drive and management are realized on STM32 micro-controller, thereby verifying design effectiveness and feasibility.

Binary synaptic connections based on memory switching in a-Si:H for artificial neural networks

NASA Technical Reports Server (NTRS)

Thakoor, A. P.; Lamb, J. L.; Moopenn, A.; Khanna, S. K.

1987-01-01

A scheme for nonvolatile associative electronic memory storage with high information storage density is proposed which is based on neural network models and which uses a matrix of two-terminal passive interconnections (synapses). It is noted that the massive parallelism in the architecture would require the ON state of a synaptic connection to be unusually weak (highly resistive). Memory switching using a-Si:H along with ballast resistors patterned from amorphous Ge-metal alloys is investigated for a binary programmable read only memory matrix. The fabrication of a 1600 synapse test array of uniform connection strengths and a-Si:H switching elements is discussed.

Virtual memory support for distributed computing environments using a shared data object model

NASA Astrophysics Data System (ADS)

Huang, F.; Bacon, J.; Mapp, G.

1995-12-01

Conventional storage management systems provide one interface for accessing memory segments and another for accessing secondary storage objects. This hinders application programming and affects overall system performance due to mandatory data copying and user/kernel boundary crossings, which in the microkernel case may involve context switches. Memory-mapping techniques may be used to provide programmers with a unified view of the storage system. This paper extends such techniques to support a shared data object model for distributed computing environments in which good support for coherence and synchronization is essential. The approach is based on a microkernel, typed memory objects, and integrated coherence control. A microkernel architecture is used to support multiple coherence protocols and the addition of new protocols. Memory objects are typed and applications can choose the most suitable protocols for different types of object to avoid protocol mismatch. Low-level coherence control is integrated with high-level concurrency control so that the number of messages required to maintain memory coherence is reduced and system-wide synchronization is realized without severely impacting the system performance. These features together contribute a novel approach to the support for flexible coherence under application control.

Inverse Resistance Change Cr2Ge2Te6-Based PCRAM Enabling Ultralow-Energy Amorphization.

PubMed

Hatayama, Shogo; Sutou, Yuji; Shindo, Satoshi; Saito, Yuta; Song, Yun-Heub; Ando, Daisuke; Koike, Junichi

2018-01-24

Phase-change random access memory (PCRAM) has attracted much attention for next-generation nonvolatile memory that can replace flash memory and can be used for storage-class memory. Generally, PCRAM relies on the change in the electrical resistance of a phase-change material between high-resistance amorphous (reset) and low-resistance crystalline (set) states. Herein, we present an inverse resistance change PCRAM with Cr 2 Ge 2 Te 6 (CrGT) that shows a high-resistance crystalline reset state and a low-resistance amorphous set state. The inverse resistance change was found to be due to a drastic decrease in the carrier density upon crystallization, which causes a large increase in contact resistivity between CrGT and the electrode. The CrGT memory cell was demonstrated to show fast reversible resistance switching with a much lower operating energy for amorphization than a Ge 2 Sb 2 Te 5 memory cell. This low operating energy in CrGT should be due to a small programmed amorphous volume, which can be realized by a high-resistance crystalline matrix and a dominant contact resistance. Simultaneously, CrGT can break the trade-off relationship between the crystallization temperature and operating speed.

INVESTIGATION OF INORGANIC PHOTOTROPIC MATERIALS AS A BI-OPTIC ELEMENT APPLICABLE IN HIGH DENSITY STORAGE COMPUTER MEMORIES

DTIC Science & Technology

A general valuation of the various types of phototropic (i.e., reversible, light induced, color producing) phenomenon is given regarding the...application of phototropic material to bioptic high density storage media for compu er memories. The inorganic ’’F’’ center type phototropic systems were

Mapping the developmental constraints on working memory span performance.

PubMed

Bayliss, Donna M; Jarrold, Christopher; Baddeley, Alan D; Gunn, Deborah M; Leigh, Eleanor

2005-07-01

This study investigated the constraints underlying developmental improvements in complex working memory span performance among 120 children of between 6 and 10 years of age. Independent measures of processing efficiency, storage capacity, rehearsal speed, and basic speed of processing were assessed to determine their contribution to age-related variance in complex span. Results showed that developmental improvements in complex span were driven by 2 age-related but separable factors: 1 associated with general speed of processing and 1 associated with storage ability. In addition, there was an age-related contribution shared between working memory, processing speed, and storage ability that was important for higher level cognition. These results pose a challenge for models of complex span performance that emphasize the importance of processing speed alone.

Quantum teleportation between remote atomic-ensemble quantum memories

PubMed Central

Bao, Xiao-Hui; Xu, Xiao-Fan; Li, Che-Ming; Yuan, Zhen-Sheng; Lu, Chao-Yang; Pan, Jian-Wei

2012-01-01

Quantum teleportation and quantum memory are two crucial elements for large-scale quantum networks. With the help of prior distributed entanglement as a “quantum channel,” quantum teleportation provides an intriguing means to faithfully transfer quantum states among distant locations without actual transmission of the physical carriers [Bennett CH, et al. (1993) Phys Rev Lett 70(13):1895–1899]. Quantum memory enables controlled storage and retrieval of fast-flying photonic quantum bits with stationary matter systems, which is essential to achieve the scalability required for large-scale quantum networks. Combining these two capabilities, here we realize quantum teleportation between two remote atomic-ensemble quantum memory nodes, each composed of ∼108 rubidium atoms and connected by a 150-m optical fiber. The spin wave state of one atomic ensemble is mapped to a propagating photon and subjected to Bell state measurements with another single photon that is entangled with the spin wave state of the other ensemble. Two-photon detection events herald the success of teleportation with an average fidelity of 88(7)%. Besides its fundamental interest as a teleportation between two remote macroscopic objects, our technique may be useful for quantum information transfer between different nodes in quantum networks and distributed quantum computing. PMID:23144222

New Trends of Digital Data Storage in DNA

PubMed Central

2016-01-01

With the exponential growth in the capacity of information generated and the emerging need for data to be stored for prolonged period of time, there emerges a need for a storage medium with high capacity, high storage density, and possibility to withstand extreme environmental conditions. DNA emerges as the prospective medium for data storage with its striking features. Diverse encoding models for reading and writing data onto DNA, codes for encrypting data which addresses issues of error generation, and approaches for developing codons and storage styles have been developed over the recent past. DNA has been identified as a potential medium for secret writing, which achieves the way towards DNA cryptography and stenography. DNA utilized as an organic memory device along with big data storage and analytics in DNA has paved the way towards DNA computing for solving computational problems. This paper critically analyzes the various methods used for encoding and encrypting data onto DNA while identifying the advantages and capability of every scheme to overcome the drawbacks identified priorly. Cryptography and stenography techniques have been analyzed in a critical approach while identifying the limitations of each method. This paper also identifies the advantages and limitations of DNA as a memory device and memory applications. PMID:27689089

New Trends of Digital Data Storage in DNA.

PubMed

De Silva, Pavani Yashodha; Ganegoda, Gamage Upeksha

With the exponential growth in the capacity of information generated and the emerging need for data to be stored for prolonged period of time, there emerges a need for a storage medium with high capacity, high storage density, and possibility to withstand extreme environmental conditions. DNA emerges as the prospective medium for data storage with its striking features. Diverse encoding models for reading and writing data onto DNA, codes for encrypting data which addresses issues of error generation, and approaches for developing codons and storage styles have been developed over the recent past. DNA has been identified as a potential medium for secret writing, which achieves the way towards DNA cryptography and stenography. DNA utilized as an organic memory device along with big data storage and analytics in DNA has paved the way towards DNA computing for solving computational problems. This paper critically analyzes the various methods used for encoding and encrypting data onto DNA while identifying the advantages and capability of every scheme to overcome the drawbacks identified priorly. Cryptography and stenography techniques have been analyzed in a critical approach while identifying the limitations of each method. This paper also identifies the advantages and limitations of DNA as a memory device and memory applications.

The loss of episodic memories in retrograde amnesia: single-case and group studies.

PubMed

Kopelman, M D; Kapur, N

2001-09-29

Retrograde amnesia in neurological disorders is a perplexing and fascinating research topic. The severity of retrograde amnesia is not well correlated with that of anterograde amnesia, and there can be disproportionate impairments of either. Within retrograde amnesia, there are various dissociations which have been claimed-for example, between the more autobiographical (episodic) and more semantic components of memory. However, the associations of different types of retrograde amnesia are also important, and clarification of these issues is confounded by the fact that retrograde amnesia seems to be particularly vulnerable to psychogenic factors. Large frontal and temporal lobe lesions have been postulated as critical in producing retrograde amnesia. Theories of retrograde amnesia have encompassed storage versus access disruption, physiological processes of 'consolidation', the progressive transformation of episodic memories into a more 'semantic' form, and multiple-trace theory. Single-case investigations, group studies and various forms of neuroimaging can all contribute to the resolution of these controversies.

Filamentary model in resistive switching materials

NASA Astrophysics Data System (ADS)

Jasmin, Alladin C.

2017-12-01

The need for next generation computer devices is increasing as the demand for efficient data processing increases. The amount of data generated every second also increases which requires large data storage devices. Oxide-based memory devices are being studied to explore new research frontiers thanks to modern advances in nanofabrication. Various oxide materials are studied as active layers for non-volatile memory. This technology has potential application in resistive random-access-memory (ReRAM) and can be easily integrated in CMOS technologies. The long term perspective of this research field is to develop devices which mimic how the brain processes information. To realize such application, a thorough understanding of the charge transport and switching mechanism is important. A new perspective in the multistate resistive switching based on current-induced filament dynamics will be discussed. A simple equivalent circuit of the device gives quantitative information about the nature of the conducting filament at different resistance states.

Exploration of depth modeling mode one lossless wedgelets storage strategies for 3D-high efficiency video coding

NASA Astrophysics Data System (ADS)

Sanchez, Gustavo; Marcon, César; Agostini, Luciano Volcan

2018-01-01

The 3D-high efficiency video coding has introduced tools to obtain higher efficiency in 3-D video coding, and most of them are related to the depth maps coding. Among these tools, the depth modeling mode-1 (DMM-1) focuses on better encoding edges regions of depth maps. The large memory required for storing all wedgelet patterns is one of the bottlenecks in the DMM-1 hardware design of both encoder and decoder since many patterns must be stored. Three algorithms to reduce the DMM-1 memory requirements and a hardware design targeting the most efficient among these algorithms are presented. Experimental results demonstrate that the proposed solutions surpass related works reducing up to 78.8% of the wedgelet memory, without degrading the encoding efficiency. Synthesis results demonstrate that the proposed algorithm reduces almost 75% of the power dissipation when compared to the standard approach.

Dopaminergic neurons write and update memories with cell-type-specific rules

PubMed Central

Aso, Yoshinori; Rubin, Gerald M

2016-01-01

Associative learning is thought to involve parallel and distributed mechanisms of memory formation and storage. In Drosophila, the mushroom body (MB) is the major site of associative odor memory formation. Previously we described the anatomy of the adult MB and defined 20 types of dopaminergic neurons (DANs) that each innervate distinct MB compartments (Aso et al., 2014a, 2014b). Here we compare the properties of memories formed by optogenetic activation of individual DAN cell types. We found extensive differences in training requirements for memory formation, decay dynamics, storage capacity and flexibility to learn new associations. Even a single DAN cell type can either write or reduce an aversive memory, or write an appetitive memory, depending on when it is activated relative to odor delivery. Our results show that different learning rules are executed in seemingly parallel memory systems, providing multiple distinct circuit-based strategies to predict future events from past experiences. DOI: http://dx.doi.org/10.7554/eLife.16135.001 PMID:27441388

High-speed noise-free optical quantum memory

NASA Astrophysics Data System (ADS)

Kaczmarek, K. T.; Ledingham, P. M.; Brecht, B.; Thomas, S. E.; Thekkadath, G. S.; Lazo-Arjona, O.; Munns, J. H. D.; Poem, E.; Feizpour, A.; Saunders, D. J.; Nunn, J.; Walmsley, I. A.

2018-04-01

Optical quantum memories are devices that store and recall quantum light and are vital to the realization of future photonic quantum networks. To date, much effort has been put into improving storage times and efficiencies of such devices to enable long-distance communications. However, less attention has been devoted to building quantum memories which add zero noise to the output. Even small additional noise can render the memory classical by destroying the fragile quantum signatures of the stored light. Therefore, noise performance is a critical parameter for all quantum memories. Here we introduce an intrinsically noise-free quantum memory protocol based on two-photon off-resonant cascaded absorption (ORCA). We demonstrate successful storage of GHz-bandwidth heralded single photons in a warm atomic vapor with no added noise, confirmed by the unaltered photon-number statistics upon recall. Our ORCA memory meets the stringent noise requirements for quantum memories while combining high-speed and room-temperature operation with technical simplicity, and therefore is immediately applicable to low-latency quantum networks.

Scalability improvements to NRLMOL for DFT calculations of large molecules

NASA Astrophysics Data System (ADS)

Diaz, Carlos Manuel

Advances in high performance computing (HPC) have provided a way to treat large, computationally demanding tasks using thousands of processors. With the development of more powerful HPC architectures, the need to create efficient and scalable code has grown more important. Electronic structure calculations are valuable in understanding experimental observations and are routinely used for new materials predictions. For the electronic structure calculations, the memory and computation time are proportional to the number of atoms. Memory requirements for these calculations scale as N2, where N is the number of atoms. While the recent advances in HPC offer platforms with large numbers of cores, the limited amount of memory available on a given node and poor scalability of the electronic structure code hinder their efficient usage of these platforms. This thesis will present some developments to overcome these bottlenecks in order to study large systems. These developments, which are implemented in the NRLMOL electronic structure code, involve the use of sparse matrix storage formats and the use of linear algebra using sparse and distributed matrices. These developments along with other related development now allow ground state density functional calculations using up to 25,000 basis functions and the excited state calculations using up to 17,000 basis functions while utilizing all cores on a node. An example on a light-harvesting triad molecule is described. Finally, future plans to further improve the scalability will be presented.

Formation of SiGe nanocrystals embedded in Al2O3 for the application of write-once-read-many-times memory

NASA Astrophysics Data System (ADS)

Wu, Min-Lin; Wu, Yung-Hsien; Lin, Chia-Chun; Chen, Lun-Lun

2012-10-01

The structure of SiGe nanocrystals embedded in Al2O3 formed by sequential deposition of Al2O3/Si/Ge/Al2O3 and a subsequent annealing was confirmed by transmission electron microscopy and energy dispersive spectroscopy (EDS), and its application for write-once-read-many-times (WORM) memory devices was explored in this study. By applying a -10 V pulse for 1 s, a large amount of holes injected from Si substrate are stored in the nanocrystals and consequently, the current at +1.5 V increases by a factor of 104 as compared to that of the initial state. Even with a smaller -5 V pulse for 1 μs, a sufficiently large current ratio of 36 can still be obtained, verifying the low power operation. Since holes are stored in nanocrystals which are isolated from Si substrate by Al2O3 with good integrity and correspond to a large valence band offset with respect to Al2O3, desirable read endurance up to 105 cycles and excellent retention over 100 yr are achieved. Combining these promising characteristics, WORM memory devices are appropriate for high-performance archival storage applications.

ADHD and working memory: the impact of central executive deficits and exceeding storage/rehearsal capacity on observed inattentive behavior.

PubMed

Kofler, Michael J; Rapport, Mark D; Bolden, Jennifer; Sarver, Dustin E; Raiker, Joseph S

2010-02-01

Inattentive behavior is considered a core and pervasive feature of ADHD; however, an alternative model challenges this premise and hypothesizes a functional relationship between working memory deficits and inattentive behavior. The current study investigated whether inattentive behavior in children with ADHD is functionally related to the domain-general central executive and/or subsidiary storage/rehearsal components of working memory. Objective observations of children's attentive behavior by independent observers were conducted while children with ADHD (n = 15) and typically developing children (n = 14) completed counterbalanced tasks that differentially manipulated central executive, phonological storage/rehearsal, and visuospatial storage/rehearsal demands. Results of latent variable and effect size confidence interval analyses revealed two conditions that completely accounted for the attentive behavior deficits in children with ADHD: (a) placing demands on central executive processing, the effect of which is evident under even low cognitive loads, and (b) exceeding storage/rehearsal capacity, which has similar effects on children with ADHD and typically developing children but occurs at lower cognitive loads for children with ADHD.

Massive Memory Revisited: Limitations on Storage Capacity for Object Details in Visual Long-Term Memory

ERIC Educational Resources Information Center

Cunningham, Corbin A.; Yassa, Michael A.; Egeth, Howard E.

2015-01-01

Previous work suggests that visual long-term memory (VLTM) is highly detailed and has a massive capacity. However, memory performance is subject to the effects of the type of testing procedure used. The current study examines detail memory performance by probing the same memories within the same subjects, but using divergent probing methods. The…

Highly Stretchable Non-volatile Nylon Thread Memory

NASA Astrophysics Data System (ADS)

Kang, Ting-Kuo

2016-04-01

Integration of electronic elements into textiles, to afford e-textiles, can provide an ideal platform for the development of lightweight, thin, flexible, and stretchable e-textiles. This approach will enable us to meet the demands of the rapidly growing market of wearable-electronics on arbitrary non-conventional substrates. However the actual integration of the e-textiles that undergo mechanical deformations during both assembly and daily wear or satisfy the requirements of the low-end applications, remains a challenge. Resistive memory elements can also be fabricated onto a nylon thread (NT) for e-textile applications. In this study, a simple dip-and-dry process using graphene-PEDOT:PSS (poly(3,4-ethylenedioxythiophene) polystyrene sulfonate) ink is proposed for the fabrication of a highly stretchable non-volatile NT memory. The NT memory appears to have typical write-once-read-many-times characteristics. The results show that an ON/OFF ratio of approximately 103 is maintained for a retention time of 106 s. Furthermore, a highly stretchable strain and a long-term digital-storage capability of the ON-OFF-ON states are demonstrated in the NT memory. The actual integration of the knitted NT memories into textiles will enable new design possibilities for low-cost and large-area e-textile memory applications.

Perturbation schedule does not alter retention of a locomotor adaptation across days.

PubMed

Hussain, Sara J; Morton, Susanne M

2014-06-15

Motor adaptation in response to gradual vs. abrupt perturbation schedules may involve different neural mechanisms, potentially leading to different levels of motor memory. However, no study has investigated whether perturbation schedules alter memory of a locomotor adaptation across days. We measured adaptation and retention (memory) of altered interlimb symmetry during walking in two groups of participants over 2 days. On day 1, participants adapted to either a single, large perturbation (abrupt schedule) or a series of small perturbations that increased in size over time (gradual schedule). Retention was examined on day 2. On day 1, initial swing time and foot placement symmetry error sizes differed between groups but overall adaptation magnitudes were similar. On day 2, participants in both groups showed similar retention, readaptation, and aftereffect sizes, although there were some trends for improved memory in the abrupt group. These results conflict with previous data but are consistent with newer studies reporting no behavioral differences following adaptation using abrupt vs. gradual schedules. Although memory levels were very similar between groups, we cannot rule out the possibility that the neural mechanisms underlying this memory storage differ. Overall, it appears that adaptation of locomotor patterns via abrupt and gradual perturbation schedules produces similar expression of locomotor memories across days. Copyright © 2014 the American Physiological Society.

Storage and computationally efficient permutations of factorized covariance and square-root information arrays

NASA Technical Reports Server (NTRS)

Muellerschoen, R. J.

1988-01-01

A unified method to permute vector stored Upper triangular Diagonal factorized covariance and vector stored upper triangular Square Root Information arrays is presented. The method involves cyclic permutation of the rows and columns of the arrays and retriangularization with fast (slow) Givens rotations (reflections). Minimal computation is performed, and a one dimensional scratch array is required. To make the method efficient for large arrays on a virtual memory machine, computations are arranged so as to avoid expensive paging faults. This method is potentially important for processing large volumes of radio metric data in the Deep Space Network.

Stream Processors

NASA Astrophysics Data System (ADS)

Erez, Mattan; Dally, William J.

Stream processors, like other multi core architectures partition their functional units and storage into multiple processing elements. In contrast to typical architectures, which contain symmetric general-purpose cores and a cache hierarchy, stream processors have a significantly leaner design. Stream processors are specifically designed for the stream execution model, in which applications have large amounts of explicit parallel computation, structured and predictable control, and memory accesses that can be performed at a coarse granularity. Applications in the streaming model are expressed in a gather-compute-scatter form, yielding programs with explicit control over transferring data to and from on-chip memory. Relying on these characteristics, which are common to many media processing and scientific computing applications, stream architectures redefine the boundary between software and hardware responsibilities with software bearing much of the complexity required to manage concurrency, locality, and latency tolerance. Thus, stream processors have minimal control consisting of fetching medium- and coarse-grained instructions and executing them directly on the many ALUs. Moreover, the on-chip storage hierarchy of stream processors is under explicit software control, as is all communication, eliminating the need for complex reactive hardware mechanisms.

How Does Processing Affect Storage in Working Memory Tasks? Evidence for Both Domain-General and Domain-Specific Effects

ERIC Educational Resources Information Center

Jarrold, Christopher; Tam, Helen; Baddeley, Alan D.; Harvey, Caroline E.

2011-01-01

Two studies that examine whether the forgetting caused by the processing demands of working memory tasks is domain-general or domain-specific are presented. In each, separate groups of adult participants were asked to carry out either verbal or nonverbal operations on exactly the same processing materials while maintaining verbal storage items.…

Disentangling the Relationship between Working Memory and Language: The Roles of Short-Term Storage and Cognitive Control

ERIC Educational Resources Information Center

Engel de Abreu, Pascale Marguerite Josiane; Gathercole, Susan Elizabeth; Martin, Romain

2011-01-01

This study investigates the relationship between working memory and language in young children growing up in a multilingual environment. The aim is to explore whether mechanisms of short-term storage and cognitive control hold similar relations to emerging language skills and to investigate if potential links are mediated by related cognitive…

Medial prefrontal cortex dopamine controls the persistent storage of aversive memories

PubMed Central

Gonzalez, María C.; Kramar, Cecilia P.; Tomaiuolo, Micol; Katche, Cynthia; Weisstaub, Noelia; Cammarota, Martín; Medina, Jorge H.

2014-01-01

Medial prefrontal cortex (mPFC) is essential for initial memory processing and expression but its involvement in persistent memory storage has seldom been studied. Using the hippocampus dependent inhibitory avoidance learning task and the hippocampus-independent conditioned taste aversion paradigm together with specific dopamine receptor agonists and antagonists we found that persistence but not formation of long-term aversive memories requires dopamine D1/D5 receptors activation in mPFC immediately after training and, depending on the task, between 6 and 12 h later. Our results indicate that besides its well-known participation in retrieval and early consolidation, mPFC also modulates the endurance of long-lasting aversive memories regardless of whether formation of the aversive mnemonic trace requires the participation of the hippocampus. PMID:25506318

SeqCompress: an algorithm for biological sequence compression.

PubMed

Sardaraz, Muhammad; Tahir, Muhammad; Ikram, Ataul Aziz; Bajwa, Hassan

2014-10-01

The growth of Next Generation Sequencing technologies presents significant research challenges, specifically to design bioinformatics tools that handle massive amount of data efficiently. Biological sequence data storage cost has become a noticeable proportion of total cost in the generation and analysis. Particularly increase in DNA sequencing rate is significantly outstripping the rate of increase in disk storage capacity, which may go beyond the limit of storage capacity. It is essential to develop algorithms that handle large data sets via better memory management. This article presents a DNA sequence compression algorithm SeqCompress that copes with the space complexity of biological sequences. The algorithm is based on lossless data compression and uses statistical model as well as arithmetic coding to compress DNA sequences. The proposed algorithm is compared with recent specialized compression tools for biological sequences. Experimental results show that proposed algorithm has better compression gain as compared to other existing algorithms. Copyright © 2014 Elsevier Inc. All rights reserved.

Storage and retrieval of electromagnetic waves with orbital angular momentum via plasmon-induced transparency.

PubMed

Bai, Zhengyang; Xu, Datang; Huang, Guoxiang

2017-01-23

We propose a scheme to realize the storage and retrieval of high-dimensional electromagnetic waves with orbital angular momentum (OAM) via plasmon-induced transparency (PIT) in a metamaterial, which consists of an array of meta-atoms constructed by a metallic structure loaded with two varactors. We show that due to PIT effect the system allows the existence of shape-preserving dark-mode plasmonic polaritons, which are mixture of electromagnetic-wave modes and dark oscillatory modes of the meta-atoms and may carry various OAMs. We demonstrate that the slowdown, storage and retrieval of multi-mode electromagnetic waves with OAMs can be achieved through the active manipulation of a control field. Our work raises the possibility for realizing PIT-based spatial multi-mode memory of electromagnetic waves and is promising for practical application of information processing with large capacity by using room-temperature metamaterials.

Electrically-controlled nonlinear switching and multi-level storage characteristics in WOx film-based memory cells

NASA Astrophysics Data System (ADS)

Duan, W. J.; Wang, J. B.; Zhong, X. L.

2018-05-01

Resistive switching random access memory (RRAM) is considered as a promising candidate for the next generation memory due to its scalability, high integration density and non-volatile storage characteristics. Here, the multiple electrical characteristics in Pt/WOx/Pt cells are investigated. Both of the nonlinear switching and multi-level storage can be achieved by setting different compliance current in the same cell. The correlations among the current, time and temperature are analyzed by using contours and 3D surfaces. The switching mechanism is explained in terms of the formation and rupture of conductive filament which is related to oxygen vacancies. The experimental results show that the non-stoichiometric WOx film-based device offers a feasible way for the applications of oxide-based RRAMs.

Positive affect improves working memory: implications for controlled cognitive processing.

PubMed

Yang, Hwajin; Yang, Sujin; Isen, Alice M

2013-01-01

This study examined the effects of positive affect on working memory (WM) and short-term memory (STM). Given that WM involves both storage and controlled processing and that STM primarily involves storage processing, we hypothesised that if positive affect facilitates controlled processing, it should improve WM more than STM. The results demonstrated that positive affect, compared with neutral affect, significantly enhanced WM, as measured by the operation span task. The influence of positive affect on STM, however, was weaker. These results suggest that positive affect enhances WM, a task that involves controlled processing, not just storage processing. Additional analyses of recall and processing times and accuracy further suggest that improved WM under positive affect is not attributable to motivational differences, but results instead from improved controlled cognitive processing.

Spectral multiplexing for scalable quantum photonics using an atomic frequency comb quantum memory and feed-forward control.

PubMed

Sinclair, Neil; Saglamyurek, Erhan; Mallahzadeh, Hassan; Slater, Joshua A; George, Mathew; Ricken, Raimund; Hedges, Morgan P; Oblak, Daniel; Simon, Christoph; Sohler, Wolfgang; Tittel, Wolfgang

2014-08-01

Future multiphoton applications of quantum optics and quantum information science require quantum memories that simultaneously store many photon states, each encoded into a different optical mode, and enable one to select the mapping between any input and a specific retrieved mode during storage. Here we show, with the example of a quantum repeater, how to employ spectrally multiplexed states and memories with fixed storage times that allow such mapping between spectral modes. Furthermore, using a Ti:Tm:LiNbO_{3} waveguide cooled to 3 K, a phase modulator, and a spectral filter, we demonstrate storage followed by the required feed-forward-controlled frequency manipulation with time-bin qubits encoded into up to 26 multiplexed spectral modes and 97% fidelity.

High-density magnetoresistive random access memory operating at ultralow voltage at room temperature.

PubMed

Hu, Jia-Mian; Li, Zheng; Chen, Long-Qing; Nan, Ce-Wen

2011-11-22

The main bottlenecks limiting the practical applications of current magnetoresistive random access memory (MRAM) technology are its low storage density and high writing energy consumption. Although a number of proposals have been reported for voltage-controlled memory device in recent years, none of them simultaneously satisfy the important device attributes: high storage capacity, low power consumption and room temperature operation. Here we present, using phase-field simulations, a simple and new pathway towards high-performance MRAMs that display significant improvements over existing MRAM technologies or proposed concepts. The proposed nanoscale MRAM device simultaneously exhibits ultrahigh storage capacity of up to 88 Gb inch(-2), ultralow power dissipation as low as 0.16 fJ per bit and room temperature high-speed operation below 10 ns.

High-density magnetoresistive random access memory operating at ultralow voltage at room temperature

PubMed Central

Hu, Jia-Mian; Li, Zheng; Chen, Long-Qing; Nan, Ce-Wen

2011-01-01

The main bottlenecks limiting the practical applications of current magnetoresistive random access memory (MRAM) technology are its low storage density and high writing energy consumption. Although a number of proposals have been reported for voltage-controlled memory device in recent years, none of them simultaneously satisfy the important device attributes: high storage capacity, low power consumption and room temperature operation. Here we present, using phase-field simulations, a simple and new pathway towards high-performance MRAMs that display significant improvements over existing MRAM technologies or proposed concepts. The proposed nanoscale MRAM device simultaneously exhibits ultrahigh storage capacity of up to 88 Gb inch−2, ultralow power dissipation as low as 0.16 fJ per bit and room temperature high-speed operation below 10 ns. PMID:22109527

Photoelectrochemical information storage using an azobenzene derivative

NASA Astrophysics Data System (ADS)

Liu, Z. F.; Hashimoto, K.; Fujishima, A.

1990-10-01

HIGH-DENSITY information storage is becoming an increasingly important technological objective. The 'heat-mode' storage techniques (in which only the thermal energy of laser light is used in the recording process and hence information usually stored as a physical change of the storage media) that are used in current optical memories are limited by the diffraction properties of light1, and the alternative 'photon-mode' (in which information is stored as a photon-induced chemical change of the storage media) has attracted attention recently for high-density storage. The most promising candidates for realizing this mode seem to be photochro-ism and photochemical hole burning; but these have some intrinsic drawbacks1,2. Here we present a novel 'photon-mode' technique that uses the photoelectrochemical properties of a Langmuir-Blodgett film of an azobenzene derivative. The system can be interconverted photochemically or electrochemically between three chemical states, and this three-state system is shown to provide a potential storage process that allows for ultra-high storage density, multi-function memory and non-destructive information readout.

BDNF is essential to promote persistence of long-term memory storage

PubMed Central

Bekinschtein, Pedro; Cammarota, Martín; Katche, Cynthia; Slipczuk, Leandro; Rossato, Janine I.; Goldin, Andrea; Izquierdo, Ivan; Medina, Jorge H.

2008-01-01

Persistence is a characteristic attribute of long-term memories (LTMs). However, little is known about the molecular mechanisms that mediate this process. We recently showed that persistence of LTM requires a late protein synthesis- and BDNF-dependent phase in the hippocampus. Here, we show that intrahippocampal delivery of BDNF reverses the deficit in memory persistence caused by inhibition of hippocampal protein synthesis. Importantly, we demonstrate that BDNF induces memory persistence by itself, transforming a nonlasting LTM trace into a persistent one in an ERK-dependent manner. Thus, BDNF is not only necessary, but sufficient to induce a late postacquisition phase in the hippocampus essential for persistence of LTM storage. PMID:18263738

Non-volatile memory for checkpoint storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blumrich, Matthias A.; Chen, Dong; Cipolla, Thomas M.

A system, method and computer program product for supporting system initiated checkpoints in high performance parallel computing systems and storing of checkpoint data to a non-volatile memory storage device. The system and method generates selective control signals to perform checkpointing of system related data in presence of messaging activity associated with a user application running at the node. The checkpointing is initiated by the system such that checkpoint data of a plurality of network nodes may be obtained even in the presence of user applications running on highly parallel computers that include ongoing user messaging activity. In one embodiment, themore » non-volatile memory is a pluggable flash memory card.« less

The Longevity of Hippocampus-Dependent Memory Is Orchestrated by the Locus Coeruleus-Noradrenergic System

PubMed Central

2017-01-01

The locus coeruleus is connected to the dorsal hippocampus via strong fiber projections. It becomes activated after arousal and novelty, whereupon noradrenaline is released in the hippocampus. Noradrenaline from the locus coeruleus is involved in modulating the encoding, consolidation, retrieval, and reversal of hippocampus-based memory. Memory storage can be modified by the activation of the locus coeruleus and subsequent facilitation of hippocampal long-term plasticity in the forms of long-term depression and long-term potentiation. Recent evidence indicates that noradrenaline and dopamine are coreleased in the hippocampus from locus coeruleus terminals, thus fostering neuromodulation of long-term synaptic plasticity and memory. Noradrenaline is an inductor of epigenetic modifications regulating transcriptional control of synaptic long-term plasticity to gate the endurance of memory storage. In conclusion, locus coeruleus activation primes the persistence of hippocampus-based long-term memory. PMID:28695015

The Role and Mechanisms of Action of Glucocorticoid Involvement in Memory Storage

PubMed Central

Sandi, Carmen

1998-01-01

Adrenal steroid hormones modulate learning and memory processes by interacting with specific glucocorticoid receptors at different brain areas. In this article, certain components of the physiological response to stress elicited by learning situations are proposed to form an integral aspect of the neurobiological mechanism underlying memory formation. By reviewing the work carried out in different learning models in chicks (passive avoidance learning) and rats (spatial orientation in the Morris water maze and contextual fear conditioning), a role for brain corticosterone action through the glucocorticoid receptor type on the mechanisms of memory consolidation is hypothesized. Evidence is also presented to relate post-training corticosterone levels to the strength of memory storage. Finally, the possible molecular mechanisms that might mediate the influences of glucocorticoids in synaptic plasticity subserving long-term memory formation are considered, mainly by focusing on studies implicating a steroid action through (i) glutamatergic transmission and (ii) cell adhesion molecules. PMID:9920681

Functional Integrity of the Retrosplenial Cortex Is Essential for Rapid Consolidation and Recall of Fear Memory

ERIC Educational Resources Information Center

Katche, Cynthia; Dorman, Guido; Slipczuk, Leandro; Cammarota, Martin; Medina, Jorge H.

2013-01-01

Memory storage is a temporally graded process involving different phases and different structures in the mammalian brain. Cortical plasticity is essential to store stable memories, but little is known regarding its involvement in memory processing. Here we show that fear memory consolidation requires early post-training macromolecular synthesis in…

Associative memory cells and their working principle in the brain

PubMed Central

Wang, Jin-Hui; Cui, Shan

2018-01-01

The acquisition, integration and storage of exogenous associated signals are termed as associative learning and memory. The consequences and processes of associative thinking and logical reasoning based on these stored exogenous signals can be memorized as endogenous signals, which are essential for decision making, intention, and planning. Associative memory cells recruited in these primary and secondary associative memories are presumably the foundation for the brain to fulfill cognition events and emotional reactions in life, though the plasticity of synaptic connectivity and neuronal activity has been believed to be involved in learning and memory. Current reports indicate that associative memory cells are recruited by their mutual synapse innervations among co-activated brain regions to fulfill the integration, storage and retrieval of associated signals. The activation of these associative memory cells initiates information recall in the mind, and the successful activation of their downstream neurons endorses memory presentations through behaviors and emotion reactions. In this review, we aim to draw a comprehensive diagram for associative memory cells, working principle and modulation, as well as propose their roles in cognition, emotion and behaviors. PMID:29487741

Working memory is not fixed-capacity: More active storage capacity for real-world objects than for simple stimuli

PubMed Central

Brady, Timothy F.; Störmer, Viola S.; Alvarez, George A.

2016-01-01

Visual working memory is the cognitive system that holds visual information active to make it resistant to interference from new perceptual input. Information about simple stimuli—colors and orientations—is encoded into working memory rapidly: In under 100 ms, working memory ‟fills up,” revealing a stark capacity limit. However, for real-world objects, the same behavioral limits do not hold: With increasing encoding time, people store more real-world objects and do so with more detail. This boost in performance for real-world objects is generally assumed to reflect the use of a separate episodic long-term memory system, rather than working memory. Here we show that this behavioral increase in capacity with real-world objects is not solely due to the use of separate episodic long-term memory systems. In particular, we show that this increase is a result of active storage in working memory, as shown by directly measuring neural activity during the delay period of a working memory task using EEG. These data challenge fixed-capacity working memory models and demonstrate that working memory and its capacity limitations are dependent upon our existing knowledge. PMID:27325767

Working memory is not fixed-capacity: More active storage capacity for real-world objects than for simple stimuli.

PubMed

Brady, Timothy F; Störmer, Viola S; Alvarez, George A

2016-07-05

Visual working memory is the cognitive system that holds visual information active to make it resistant to interference from new perceptual input. Information about simple stimuli-colors and orientations-is encoded into working memory rapidly: In under 100 ms, working memory ‟fills up," revealing a stark capacity limit. However, for real-world objects, the same behavioral limits do not hold: With increasing encoding time, people store more real-world objects and do so with more detail. This boost in performance for real-world objects is generally assumed to reflect the use of a separate episodic long-term memory system, rather than working memory. Here we show that this behavioral increase in capacity with real-world objects is not solely due to the use of separate episodic long-term memory systems. In particular, we show that this increase is a result of active storage in working memory, as shown by directly measuring neural activity during the delay period of a working memory task using EEG. These data challenge fixed-capacity working memory models and demonstrate that working memory and its capacity limitations are dependent upon our existing knowledge.

Memory Span and General Intelligence: A Latent-Variable Approach

ERIC Educational Resources Information Center

Colom, Roberto; Abad, Francisco J.; Rebollo, Irene; Chun Shih, Pei

2005-01-01

There are several studies showing that working memory and intelligence are strongly related. However, working memory tasks require simultaneous processing and storage, so the causes of their relationship with intelligence are currently a matter of discussion. The present study examined the simultaneous relationships among short-term memory (STM),…

Fading In

ERIC Educational Resources Information Center

Nader, Karim; Wang, Szu-Han

2006-01-01

Patient H.M. can form new memories and maintain them for a few seconds before they fade away. From a neurobiological perspective, this amnesia is usually attributed to the absence of memory consolidation, that is, memory storage. An alternative view holds that this impairment reflects that the memory is present but cannot be retrieved. This debate…

Memory and Study Strategies for Optimal Learning.

ERIC Educational Resources Information Center

Hamachek, Alice L.

Study strategies are those specific reading skills that increase understanding, memory storage, and retrieval. Memory techniques are crucial to effective studying, and to subsequent performance in class and on written examinations. A major function of memory is to process information. Stimuli are picked up by sensory receptors and transferred to…

Co-design of application software and NAND flash memory in solid-state drive for relational database storage system

NASA Astrophysics Data System (ADS)

Miyaji, Kousuke; Sun, Chao; Soga, Ayumi; Takeuchi, Ken

2014-01-01

A relational database management system (RDBMS) is designed based on NAND flash solid-state drive (SSD) for storage. By vertically integrating the storage engine (SE) and the flash translation layer (FTL), system performance is maximized and the internal SSD overhead is minimized. The proposed RDBMS SE utilizes physical information about the NAND flash memory which is supplied from the FTL. The query operation is also optimized for SSD. By these treatments, page-copy-less garbage collection is achieved and data fragmentation in the NAND flash memory is suppressed. As a result, RDBMS performance increases by 3.8 times, power consumption of SSD decreases by 46% and SSD life time is increased by 61%. The effectiveness of the proposed scheme increases with larger erase block sizes, which matches the future scaling trend of three-dimensional (3D-) NAND flash memories. The preferable row data size of the proposed scheme is below 500 byte for 16 kbyte page size.

Working memory deficits in adults with attention-deficit/hyperactivity disorder (ADHD): an examination of central executive and storage/rehearsal processes.

PubMed

Alderson, R Matt; Hudec, Kristen L; Patros, Connor H G; Kasper, Lisa J

2013-05-01

The current study was the first to use a regression approach to examine the unique contributions of central executive (CE) and storage/rehearsal processes to working memory (WM) deficits in adults with ADHD. Thirty-seven adults (ADHD = 21, HC = 16) completed phonological (PH) and visuospatial (VS) working memory tasks. While both groups performed significantly better during the PH task relative to the VS task, adults with ADHD exhibited significant deficits across both working memory modalities. Further, the ADHD group recalled disproportionately fewer PH and VS stimuli as set-size demands increased. Overall, the CE and PH storage/rehearsal processes of adults with ADHD were both significantly impaired relative to those of the healthy control adults; however, the magnitude of the CE effect size was much smaller compared to previous studies of children with the disorder. Collectively, results provide support for a lifelong trajectory of WM deficits in ADHD. © 2013 American Psychological Association

A high-speed network for cardiac image review.

PubMed

Elion, J L; Petrocelli, R R

1994-01-01

A high-speed fiber-based network for the transmission and display of digitized full-motion cardiac images has been developed. Based on Asynchronous Transfer Mode (ATM), the network is scaleable, meaning that the same software and hardware is used for a small local area network or for a large multi-institutional network. The system can handle uncompressed digital angiographic images, considered to be at the "high-end" of the bandwidth requirements. Along with the networking, a general-purpose multi-modality review station has been implemented without specialized hardware. This station can store a full injection sequence in "loop RAM" in a 512 x 512 format, then interpolate to 1024 x 1024 while displaying at 30 frames per second. The network and review stations connect to a central file server that uses a virtual file system to make a large high-speed RAID storage disk and associated off-line storage tapes and cartridges all appear as a single large file system to the software. In addition to supporting archival storage and review, the system can also digitize live video using high-speed Direct Memory Access (DMA) from the frame grabber to present uncompressed data to the network. Fully functional prototypes have provided the proof of concept, with full deployment in the institution planned as the next stage.

A high-speed network for cardiac image review.

PubMed Central

Elion, J. L.; Petrocelli, R. R.

1994-01-01

A high-speed fiber-based network for the transmission and display of digitized full-motion cardiac images has been developed. Based on Asynchronous Transfer Mode (ATM), the network is scaleable, meaning that the same software and hardware is used for a small local area network or for a large multi-institutional network. The system can handle uncompressed digital angiographic images, considered to be at the "high-end" of the bandwidth requirements. Along with the networking, a general-purpose multi-modality review station has been implemented without specialized hardware. This station can store a full injection sequence in "loop RAM" in a 512 x 512 format, then interpolate to 1024 x 1024 while displaying at 30 frames per second. The network and review stations connect to a central file server that uses a virtual file system to make a large high-speed RAID storage disk and associated off-line storage tapes and cartridges all appear as a single large file system to the software. In addition to supporting archival storage and review, the system can also digitize live video using high-speed Direct Memory Access (DMA) from the frame grabber to present uncompressed data to the network. Fully functional prototypes have provided the proof of concept, with full deployment in the institution planned as the next stage. PMID:7949964

Retrograde Amnesia for Episodic and Semantic Memories in Amnestic Mild Cognitive Impairment.

PubMed

De Simone, Maria Stefania; Fadda, Lucia; Perri, Roberta; De Tollis, Massimo; Aloisi, Marta; Caltagirone, Carlo; Carlesimo, Giovanni Augusto

2017-01-01

Retrograde amnesia (RA), which includes loss of memory for past personal events (autobiographical RA) and for acquired knowledge (semantic RA), has been largely documented in patients with amnestic mild cognitive impairment (aMCI). However, previous studies have produced controversial results particularly concerning the temporal extent of memory impairment. Here we investigated whether, with the onset of hippocampal pathology, age of memory acquisition and retrieval frequency play different roles in modulating the progressive loss of semantic and episodic contents of retrograde memory respectively. For this purpose, aMCI patients and healthy controls were tested for the ability to recall semantic and autobiographical information related to famous public events as a function of both age of acquisition and retrieval frequency. In aMCI patients, we found that the impairment in recollecting past personal incidents was modulated by the combined action of memory age and retrieval frequency, because older and more frequently retrieved episodes are less susceptible to loss than more recent and less frequently retrieved ones. On the other side, we found that the loss of semantic information depended only on memory age, because the remoteness of the trace allows for better preservation of the memory. Our results provide evidence that the loss of the two components of retrograde memory is regulated by different mechanisms. This supports the view that diverse neural mechanisms are involved in episodic and semantic memory trace storage and retrieval, as postulated by the Multiple Trace Theory.

Thermomechanical Characterization of Shape Memory Polymers using High Temperature Nanoindentation

DTIC Science & Technology

2010-01-01

Beake and Smith [17] have reported high temperature nano- indentation experiments on fused silica and soda – lime glass . Volinsky et al. [18] and Sawant...activated at room temperature. A large amount of ‘‘sink-in’’ is observed at the SMP surface when activated at temperatures above its glass transition...should be above thematerial’s glass transition temperature, Tg. Secondly, the constrained SMP is cooled to the storage temperature, Ts, which is below

Robust hippocampal responsivity during retrieval of consolidated associative memory.

PubMed

Hattori, Shoai; Chen, Lillian; Weiss, Craig; Disterhoft, John F

2015-05-01

A contentious point in memory research is whether or not the hippocampus plays a time-limited role in the consolidation of declarative memories. A widely held view is that declarative memories are initially encoded in the hippocampus, then transferred to the neocortex for long-term storage. Alternate views argue instead that the hippocampus continues to play a role in remote memory recall. These competing theories are largely based on human amnesic and animal lesion/inactivation studies. However, in vivo electrophysiological evidence supporting these views is scarce. Given that other studies examining the role of the hippocampus in remote memory retrieval using lesion and imaging techniques in human and animal models have provided mixed results, it would be particularly useful to gain insight at the in vivo electrophysiological level. Here we report hippocampal single-neuron and theta activity recorded longitudinally during acquisition and remote retrieval of trace eyeblink conditioning. Results from conditioned rabbits were compared to those obtained from yoked pseudo-conditioned control rabbits. Results reveal continued learning-specific hippocampal activity one month after initial acquisition of the task. Our findings yield insight into the normal physiological responses of the hippocampus during memory processes and provide compelling in vivo electrophysiological evidence that the hippocampus is involved in both acquisition and retrieval of consolidated memories. © 2014 The Authors Hippocampus Published by Wiley Periodicals, Inc.

Scandium doped Ge2Sb2Te5 for high-speed and low-power-consumption phase change memory

NASA Astrophysics Data System (ADS)

Wang, Yong; Zheng, Yonghui; Liu, Guangyu; Li, Tao; Guo, Tianqi; Cheng, Yan; Lv, Shilong; Song, Sannian; Ren, Kun; Song, Zhitang

2018-03-01

To bridge the gap of access time between memories and storage systems, the concept of storage class memory has been put forward based on emerging nonvolatile memory technologies. For all the nonvolatile memory candidates, the unpleasant tradeoff between operation speed and retention seems to be inevitable. To promote both the write speed and the retention of phase change memory (PCM), Sc doped Ge2Sb2Te5 (SGST) has been proposed as the storage medium. Octahedral Sc-Te motifs, acting as crystallization precursors to shorten the nucleation incubation period, are the possible reason for the high write speed of 6 ns in PCM cells, five-times faster than that of Ge2Sb2Te5 (GST) cells. Meanwhile, an enhanced 10-year data retention of 119 °C has been achieved. Benefiting from both the increased crystalline resistance and the inhibited formation of the hexagonal phase, the SGST cell has a 77% reduction in power consumption compared to the GST cell. Adhesion of the SGST/SiO2 interface has been strengthened, attributed to the reduced stress by forming smaller grains during crystallization, guaranteeing the reliability of the device. These improvements have made the SGST material a promising candidate for PCM application.

Setting a disordered password on a photonic memory

NASA Astrophysics Data System (ADS)

Su, Shih-Wei; Gou, Shih-Chuan; Chew, Lock Yue; Chang, Yu-Yen; Yu, Ite A.; Kalachev, Alexey; Liao, Wen-Te

2017-06-01

An all-optical method of setting a disordered password on different schemes of photonic memory is theoretically studied. While photons are regarded as ideal information carriers, it is imperative to implement such data protection on all-optical storage. However, we wish to address the intrinsic risk of data breaches in existing schemes of photonic memory. We theoretically demonstrate a protocol using spatially disordered laser fields to encrypt data stored on an optical memory, namely, encrypted photonic memory. To address the broadband storage, we also investigate a scheme of disordered echo memory with a high fidelity approaching unity. The proposed method increases the difficulty for the eavesdropper to retrieve the stored photon without the preset password even when the randomized and stored photon state is nearly perfectly cloned. Our results pave ways to significantly reduce the exposure of memories, required for long-distance communication, to eavesdropping and therefore restrict the optimal attack on communication protocols. The present scheme also increases the sensitivity of detecting any eavesdropper and so raises the security level of photonic information technology.

Selection and Storage of Perceptual Groups Is Constrained by a Discrete Resource in Working Memory

ERIC Educational Resources Information Center

Anderson, David E.; Vogel, Edward K.; Awh, Edward

2013-01-01

Perceptual grouping can lead observers to perceive a multielement scene as a smaller number of hierarchical units. Past work has shown that grouping enables more elements to be stored in visual working memory (WM). Although this may appear to contradict so-called discrete resource models that argue for fixed item limits in WM storage, it is also…

Large-memory real-time multichannel multiplexed pattern recognition

NASA Technical Reports Server (NTRS)

Gregory, D. A.; Liu, H. K.

1984-01-01

The principle and experimental design of a real-time multichannel multiplexed optical pattern recognition system via use of a 25-focus dichromated gelatin holographic lens (hololens) are described. Each of the 25 foci of the hololens may have a storage and matched filtering capability approaching that of a single-lens correlator. If the space-bandwidth product of an input image is limited, as is true in most practical cases, the 25-focus hololens system has 25 times the capability of a single lens. Experimental results have shown that the interfilter noise is not serious. The system has already demonstrated the storage and recognition of over 70 matched filters - which is a larger capacity than any optical pattern recognition system reported to date.

LOD-based clustering techniques for efficient large-scale terrain storage and visualization

NASA Astrophysics Data System (ADS)

Bao, Xiaohong; Pajarola, Renato

2003-05-01

Large multi-resolution terrain data sets are usually stored out-of-core. To visualize terrain data at interactive frame rates, the data needs to be organized on disk, loaded into main memory part by part, then rendered efficiently. Many main-memory algorithms have been proposed for efficient vertex selection and mesh construction. Organization of terrain data on disk is quite difficult because the error, the triangulation dependency and the spatial location of each vertex all need to be considered. Previous terrain clustering algorithms did not consider the per-vertex approximation error of individual terrain data sets. Therefore, the vertex sequences on disk are exactly the same for any terrain. In this paper, we propose a novel clustering algorithm which introduces the level-of-detail (LOD) information to terrain data organization to map multi-resolution terrain data to external memory. In our approach the LOD parameters of the terrain elevation points are reflected during clustering. The experiments show that dynamic loading and paging of terrain data at varying LOD is very efficient and minimizes page faults. Additionally, the preprocessing of this algorithm is very fast and works from out-of-core.

Implications of the Declarative/Procedural Model for Improving Second Language Learning: The Role of Memory Enhancement Techniques

ERIC Educational Resources Information Center

Ullman, Michael T.; Lovelett, Jarrett T.

2018-01-01

The declarative/procedural (DP) model posits that the learning, storage, and use of language critically depend on two learning and memory systems in the brain: declarative memory and procedural memory. Thus, on the basis of independent research on the memory systems, the model can generate specific and often novel predictions for language. Till…

Episodic Memory Impairments in Primary Brain Tumor Patients.

PubMed

Durand, Thomas; Berzero, Giulia; Bompaire, Flavie; Hoffmann, Sabine; Léger, Isabelle; Jego, Virginie; Baruteau, Marie; Delgadillo, Daniel; Taillia, Hervé; Psimaras, Dimitri; Ricard, Damien

2018-01-04

Cognitive investigations in brain tumor patients have mostly explored episodic memory without differentiating between encoding, storage, and retrieval deficits. The aim of this study is to offer insight into the memory sub-processes affected in primary brain tumor patients and propose an appropriate assessment method. We retrospectively reviewed the clinical and memory assessments of 158 patients with primary brain tumors who had presented to our departments with cognitive complaints and were investigated using the Free and Cued Selective Reminding Test. Retrieval was the process of episodic memory most frequently affected, with deficits in this domain detected in 92% of patients with episodic memory impairments. Storage and encoding deficits were less prevalent, with impairments, respectively, detected in 41% and 23% of memory-impaired patients. The pattern of episodic memory impairment was similar across different tumor histologies and treatment modalities. Although all processes of episodic memory were found to be impaired, retrieval was by far the most widely affected function. A thorough assessment of all three components of episodic memory should be part of the regular neuropsychological evaluation in patients with primary brain tumors. © The Author(s) 2018. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Projected phase-change memory devices.

PubMed

Koelmans, Wabe W; Sebastian, Abu; Jonnalagadda, Vara Prasad; Krebs, Daniel; Dellmann, Laurent; Eleftheriou, Evangelos

2015-09-03

Nanoscale memory devices, whose resistance depends on the history of the electric signals applied, could become critical building blocks in new computing paradigms, such as brain-inspired computing and memcomputing. However, there are key challenges to overcome, such as the high programming power required, noise and resistance drift. Here, to address these, we present the concept of a projected memory device, whose distinguishing feature is that the physical mechanism of resistance storage is decoupled from the information-retrieval process. We designed and fabricated projected memory devices based on the phase-change storage mechanism and convincingly demonstrate the concept through detailed experimentation, supported by extensive modelling and finite-element simulations. The projected memory devices exhibit remarkably low drift and excellent noise performance. We also demonstrate active control and customization of the programming characteristics of the device that reliably realize a multitude of resistance states.

Reduced electron back-injection in Al2O3/AlOx/Al2O3/graphene charge-trap memory devices

NASA Astrophysics Data System (ADS)

Lee, Sejoon; Song, Emil B.; Min Kim, Sung; Lee, Youngmin; Seo, David H.; Seo, Sunae; Wang, Kang L.

2012-12-01

A graphene charge-trap memory is devised using a single-layer graphene channel with an Al2O3/AlOx/Al2O3 oxide stack, where the ion-bombarded AlOx layer is intentionally added to create an abundance of charge-trap sites. The low dielectric constant of AlOx compared to Al2O3 reduces the potential drop in the control oxide Al2O3 and suppresses the electron back-injection from the gate to the charge-storage layer, allowing the memory window of the device to be further extended. This shows that the usage of a lower dielectric constant in the charge-storage layer compared to that of the control oxide layer improves the memory performance for graphene charge-trap memories.

Integrated Vertical Bloch Line (VBL) memory

NASA Technical Reports Server (NTRS)

Katti, R. R.; Wu, J. C.; Stadler, H. L.

1991-01-01

Vertical Bloch Line (VBL) Memory is a recently conceived, integrated, solid state, block access, VLSI memory which offers the potential of 1 Gbit/sq cm areal storage density, data rates of hundreds of megabits/sec, and submillisecond average access time simultaneously at relatively low mass, volume, and power values when compared to alternative technologies. VBLs are micromagnetic structures within magnetic domain walls which can be manipulated using magnetic fields from integrated conductors. The presence or absence of BVL pairs are used to store binary information. At present, efforts are being directed at developing a single chip memory using 25 Mbit/sq cm technology in magnetic garnet material which integrates, at a single operating point, the writing, storage, reading, and amplification functions needed in a memory. The current design architecture, functional elements, and supercomputer simulation results are described which are used to assist the design process.

The compression and storage method of the same kind of medical images: DPCM

NASA Astrophysics Data System (ADS)

Zhao, Xiuying; Wei, Jingyuan; Zhai, Linpei; Liu, Hong

2006-09-01

Medical imaging has started to take advantage of digital technology, opening the way for advanced medical imaging and teleradiology. Medical images, however, require large amounts of memory. At over 1 million bytes per image, a typical hospital needs a staggering amount of memory storage (over one trillion bytes per year), and transmitting an image over a network (even the promised superhighway) could take minutes--too slow for interactive teleradiology. This calls for image compression to reduce significantly the amount of data needed to represent an image. Several compression techniques with different compression ratio have been developed. However, the lossless techniques, which allow for perfect reconstruction of the original images, yield modest compression ratio, while the techniques that yield higher compression ratio are lossy, that is, the original image is reconstructed only approximately. Medical imaging poses the great challenge of having compression algorithms that are lossless (for diagnostic and legal reasons) and yet have high compression ratio for reduced storage and transmission time. To meet this challenge, we are developing and studying some compression schemes, which are either strictly lossless or diagnostically lossless, taking advantage of the peculiarities of medical images and of the medical practice. In order to increase the Signal to Noise Ratio (SNR) by exploitation of correlations within the source signal, a method of combining differential pulse code modulation (DPCM) is presented.

Origami-based tunable truss structures for non-volatile mechanical memory operation.

PubMed

Yasuda, Hiromi; Tachi, Tomohiro; Lee, Mia; Yang, Jinkyu

2017-10-17

Origami has recently received significant interest from the scientific community as a method for designing building blocks to construct metamaterials. However, the primary focus has been placed on their kinematic applications by leveraging the compactness and auxeticity of planar origami platforms. Here, we present volumetric origami cells-specifically triangulated cylindrical origami (TCO)-with tunable stability and stiffness, and demonstrate their feasibility as non-volatile mechanical memory storage devices. We show that a pair of TCO cells can develop a double-well potential to store bit information. What makes this origami-based approach more appealing is the realization of two-bit mechanical memory, in which two pairs of TCO cells are interconnected and one pair acts as a control for the other pair. By assembling TCO-based truss structures, we experimentally verify the tunable nature of the TCO units and demonstrate the operation of purely mechanical one- and two-bit memory storage prototypes.Origami is a popular method to design building blocks for mechanical metamaterials. Here, the authors assemble a volumetric origami-based structure, predict its axial and rotational movements during folding, and demonstrate the operation of mechanical one- and two-bit memory storage.

Central and Peripheral Components of Working Memory Storage

PubMed Central

Cowan, Nelson; Saults, J. Scott; Blume, Christopher L.

2014-01-01

This study re-examines the issue of how much of working memory storage is central, or shared across sensory modalities and verbal and nonverbal codes, and how much is peripheral, or specific to a modality or code. In addition to the exploration of many parameters in 9 new dual-task experiments and re-analysis of some prior evidence, the innovations of the present work compared to previous studies of memory for two stimulus sets include (1) use of a principled set of formulas to estimate the number of items in working memory, and (2) a model to dissociate central components, which are allocated to very different stimulus sets depending on the instructions, from peripheral components, which are used for only one kind of material. We consistently find that the central contribution is smaller than was suggested by Saults and Cowan (2007), and that the peripheral contribution is often much larger when the task does not require the binding of features within an object. Previous capacity estimates are consistent with the sum of central plus peripheral components observed here. We consider the implications of the data as constraints on theories of working memory storage and maintenance. PMID:24867488

Distinct Transfer Effects of Training Different Facets of Working Memory Capacity

ERIC Educational Resources Information Center

von Bastian, Claudia C.; Oberauer, Klaus

2013-01-01

The impact of working memory training on a broad set of transfer tasks was examined. Each of three groups of participants trained one specific functional category of working memory capacity: storage and processing, relational integration, and supervision. A battery comprising tests to measure working memory, task shifting, inhibition, and…

Evidence for Two Attentional Components in Visual Working Memory

ERIC Educational Resources Information Center

Allen, Richard J.; Baddeley, Alan D.; Hitch, Graham J.

2014-01-01

How does executive attentional control contribute to memory for sequences of visual objects, and what does this reveal about storage and processing in working memory? Three experiments examined the impact of a concurrent executive load (backward counting) on memory for sequences of individually presented visual objects. Experiments 1 and 2 found…

Metal-organic molecular device for non-volatile memory storage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Radha, B., E-mail: radha.boya@manchester.ac.uk, E-mail: kulkarni@jncasr.ac.in; Sagade, Abhay A.; Kulkarni, G. U., E-mail: radha.boya@manchester.ac.uk, E-mail: kulkarni@jncasr.ac.in

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-organicmore » 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.« less

Evidence for an Evolutionarily Conserved Memory Coding Scheme in the Mammalian Hippocampus

PubMed Central

Thome, Alexander; Lisanby, Sarah H.; McNaughton, Bruce L.

2017-01-01

Decades of research identify the hippocampal formation as central to memory storage and recall. Events are stored via distributed population codes, the parameters of which (e.g., sparsity and overlap) determine both storage capacity and fidelity. However, it remains unclear whether the parameters governing information storage are similar between species. Because episodic memories are rooted in the space in which they are experienced, the hippocampal response to navigation is often used as a proxy to study memory. Critically, recent studies in rodents that mimic the conditions typical of navigation studies in humans and nonhuman primates (i.e., virtual reality) show that reduced sensory input alters hippocampal representations of space. The goal of this study was to quantify this effect and determine whether there are commonalities in information storage across species. Using functional molecular imaging, we observe that navigation in virtual environments elicits activity in fewer CA1 neurons relative to real-world conditions. Conversely, comparable neuronal activity is observed in hippocampus region CA3 and the dentate gyrus under both conditions. Surprisingly, we also find evidence that the absolute number of neurons used to represent an experience is relatively stable between nonhuman primates and rodents. We propose that this convergence reflects an optimal ensemble size for episodic memories. SIGNIFICANCE STATEMENT One primary factor constraining memory capacity is the sparsity of the engram, the proportion of neurons that encode a single experience. Investigating sparsity in humans is hampered by the lack of single-cell resolution and differences in behavioral protocols. Sparsity can be quantified in freely moving rodents, but extrapolating these data to humans assumes that information storage is comparable across species and is robust to restraint-induced reduction in sensory input. Here, we test these assumptions and show that species differences in brain size build memory capacity without altering the structure of the data being stored. Furthermore, sparsity in most of the hippocampus is resilient to reduced sensory information. This information is vital to integrating animal data with human imaging navigation studies. PMID:28174334

Compressing DNA sequence databases with coil.

PubMed

White, W Timothy J; Hendy, Michael D

2008-05-20

Publicly available DNA sequence databases such as GenBank are large, and are growing at an exponential rate. The sheer volume of data being dealt with presents serious storage and data communications problems. Currently, sequence data is usually kept in large "flat files," which are then compressed using standard Lempel-Ziv (gzip) compression - an approach which rarely achieves good compression ratios. While much research has been done on compressing individual DNA sequences, surprisingly little has focused on the compression of entire databases of such sequences. In this study we introduce the sequence database compression software coil. We have designed and implemented a portable software package, coil, for compressing and decompressing DNA sequence databases based on the idea of edit-tree coding. coil is geared towards achieving high compression ratios at the expense of execution time and memory usage during compression - the compression time represents a "one-off investment" whose cost is quickly amortised if the resulting compressed file is transmitted many times. Decompression requires little memory and is extremely fast. We demonstrate a 5% improvement in compression ratio over state-of-the-art general-purpose compression tools for a large GenBank database file containing Expressed Sequence Tag (EST) data. Finally, coil can efficiently encode incremental additions to a sequence database. coil presents a compelling alternative to conventional compression of flat files for the storage and distribution of DNA sequence databases having a narrow distribution of sequence lengths, such as EST data. Increasing compression levels for databases having a wide distribution of sequence lengths is a direction for future work.

Compressing DNA sequence databases with coil

PubMed Central

White, W Timothy J; Hendy, Michael D

2008-01-01

Background Publicly available DNA sequence databases such as GenBank are large, and are growing at an exponential rate. The sheer volume of data being dealt with presents serious storage and data communications problems. Currently, sequence data is usually kept in large "flat files," which are then compressed using standard Lempel-Ziv (gzip) compression – an approach which rarely achieves good compression ratios. While much research has been done on compressing individual DNA sequences, surprisingly little has focused on the compression of entire databases of such sequences. In this study we introduce the sequence database compression software coil. Results We have designed and implemented a portable software package, coil, for compressing and decompressing DNA sequence databases based on the idea of edit-tree coding. coil is geared towards achieving high compression ratios at the expense of execution time and memory usage during compression – the compression time represents a "one-off investment" whose cost is quickly amortised if the resulting compressed file is transmitted many times. Decompression requires little memory and is extremely fast. We demonstrate a 5% improvement in compression ratio over state-of-the-art general-purpose compression tools for a large GenBank database file containing Expressed Sequence Tag (EST) data. Finally, coil can efficiently encode incremental additions to a sequence database. Conclusion coil presents a compelling alternative to conventional compression of flat files for the storage and distribution of DNA sequence databases having a narrow distribution of sequence lengths, such as EST data. Increasing compression levels for databases having a wide distribution of sequence lengths is a direction for future work. PMID:18489794

Three-dimensional magnetic bubble memory system

NASA Technical Reports Server (NTRS)

Stadler, Henry L. (Inventor); Katti, Romney R. (Inventor); Wu, Jiin-Chuan (Inventor)

1994-01-01

A compact memory uses magnetic bubble technology for providing data storage. A three-dimensional arrangement, in the form of stacks of magnetic bubble layers, is used to achieve high volumetric storage density. Output tracks are used within each layer to allow data to be accessed uniquely and unambiguously. Storage can be achieved using either current access or field access magnetic bubble technology. Optical sensing via the Faraday effect is used to detect data. Optical sensing facilitates the accessing of data from within the three-dimensional package and lends itself to parallel operation for supporting high data rates and vector and parallel processing.

Working memory capacity and the scope and control of attention.

PubMed

Shipstead, Zach; Harrison, Tyler L; Engle, Randall W

2015-08-01

Complex span and visual arrays are two common measures of working memory capacity that are respectively treated as measures of attention control and storage capacity. A recent analysis of these tasks concluded that (1) complex span performance has a relatively stronger relationship to fluid intelligence and (2) this is due to the requirement that people engage control processes while performing this task. The present study examines the validity of these conclusions by examining two large data sets that include a more diverse set of visual arrays tasks and several measures of attention control. We conclude that complex span and visual arrays account for similar amounts of variance in fluid intelligence. The disparity relative to the earlier analysis is attributed to the present study involving a more complete measure of the latent ability underlying the performance of visual arrays. Moreover, we find that both types of working memory task have strong relationships to attention control. This indicates that the ability to engage attention in a controlled manner is a critical aspect of working memory capacity, regardless of the type of task that is used to measure this construct.

Reevaluating the Sensory Account of Visual Working Memory Storage.

PubMed

Xu, Yaoda

2017-10-01

Recent human fMRI pattern-decoding studies have highlighted the involvement of sensory areas in visual working memory (VWM) tasks and argue for a sensory account of VWM storage. In this review, evidence is examined from human behavior, fMRI decoding, and transcranial magnetic stimulation (TMS) studies, as well as from monkey neurophysiology studies. Contrary to the prevalent view, the available evidence provides little support for the sensory account of VWM storage. Instead, when the ability to resist distraction and the existence of top-down feedback are taken into account, VWM-related activities in sensory areas seem to reflect feedback signals indicative of VWM storage elsewhere in the brain. Collectively, the evidence shows that prefrontal and parietal regions, rather than sensory areas, play more significant roles in VWM storage. Copyright © 2017 Elsevier Ltd. All rights reserved.

Voltage-Dependent Charge Storage in Cladded Zn0.56Cd0.44Se Quantum Dot MOS Capacitors for Multibit Memory Applications

NASA Astrophysics Data System (ADS)

Khan, J.; Lingalugari, M.; Al-Amoody, F.; Jain, F.

2013-11-01

As conventional memories approach scaling limitations, new storage methods must be utilized to increase Si yield and produce higher on-chip memory density. Use of II-VI Zn0.56Cd0.44Se quantum dots (QDs) is compatible with epitaxial gate insulators such as ZnS-ZnMgS. Voltage-dependent charging effects in cladded Zn0.56Cd0.44Se QDs are presented in a conventional metal-oxide-semiconductor capacitor structure. Charge storage capabilities in Si and ZnMgS QDs have been reported by various researchers; this work is focused on II-VI material Zn0.56Cd0.44Se QDs nucleated using photoassisted microwave plasma metalorganic chemical vapor deposition. Using capacitance-voltage hysteresis characterization, the multistep charging and discharging capabilities of the QDs at room temperature are presented. Three charging states are presented within a 10 V charging voltage range. These characteristics exemplify discrete charge states in the QD layer, perfect for multibit, QD-functionalized high-density memory applications. Multiple charge states with low operating voltage provide device characteristics that can be used for multibit storage by allowing varying charges to be stored in a QD layer based on the applied "write" voltage.

Left TPJ activity in verbal working memory: implications for storage- and sensory-specific models of short term memory.

PubMed

Ravizza, Susan M; Hazeltine, Eliot; Ruiz, Sandra; Zhu, David C

2011-04-15

Patients with damage to the left temporoparietal junction (TPJ) have a low verbal span without concomitant deficits in speech perception. This pattern of cognitive impairment is taken as evidence for a dedicated phonological buffer that plays little role in perception (storage-specific account). In contrast, other research suggests that items are maintained and perceived in the same regions (sensory-specific account). In an fMRI study, we demonstrate that the left TPJ does not respond in a way predicted of a phonological buffer; that is, activity in this region is not sustained during encoding or maintenance. Instead, a region in the superior temporal gyrus that has been associated with both speech perception and production demonstrated the expected profile of a store: it was more active in the verbal condition than the object condition and was active during both encoding and maintenance. These results support the sensory-specific account of short term memory rather than the storage-specific account. Based on the pattern of activity in the left TPJ, we suggest that the impairment of verbal working memory observed in patients with TPJ damage may be due to diminished attentional processes rather than reduced storage capacity. Copyright © 2010 Elsevier Inc. All rights reserved.

Achieving large linear elasticity and high strength in bulk nanocompsite via synergistic effect

DOE PAGES

Hao, Shijie; Cui, Lishan; Guo, Fangmin; ...

2015-03-09

Elastic strain in bulk metallic materials is usually limited to only a fraction of 1%. Developing bulk metallic materials showing large linear elasticity and high strength has proven to be difficult. Here, based on the synergistic effect between nanowires and orientated martensite NiTi shape memory alloy, we developed an in-situ Nb nanowires-orientated martensitic NiTi matrix composite showing an ultra-large linear elastic strain of 4% and an ultrahigh yield strength of 1.8 GPa. This material also has a high mechanical energy storage efficiency of 96% and a high energy storage density of 36 J/cm 3 that is almost one order ofmore » larger than that of spring steel. It is demonstrated that the synergistic effect allows the exceptional mechanical properties of nanowires to be harvested at macro scale and the mechanical properties of matrix to be greatly improved, resulting in these superior properties. This research provides new avenues for developing advanced composites with superior properties by using effective synergistic effect between components.« less

Self-consistent signal-to-noise analysis of the statistical behavior of analog neural networks and enhancement of the storage capacity

NASA Astrophysics Data System (ADS)

Shiino, Masatoshi; Fukai, Tomoki

1993-08-01

Based on the self-consistent signal-to-noise analysis (SCSNA) capable of dealing with analog neural networks with a wide class of transfer functions, enhancement of the storage capacity of associative memory and the related statistical properties of neural networks are studied for random memory patterns. Two types of transfer functions with the threshold parameter θ are considered, which are derived from the sigmoidal one to represent the output of three-state neurons. Neural networks having a monotonically increasing transfer function FM, FM(u)=sgnu (||u||>θ), FM(u)=0 (||u||<=θ), are shown to make it impossible for the spin-glass state to coexist with retrieval states in a certain parameter region of θ and α (loading rate of memory patterns), implying the reduction of the number of spurious states. The behavior of the storage capacity with changing θ is qualitatively the same as that of the Ising spin neural networks with varying temperature. On the other hand, the nonmonotonic transfer function FNM, FNM(u)=sgnu (||u||<θ), FNM(u)=0 (||u||>=θ) gives rise to remarkable features in several respects. First, it yields a large enhancement of the storage capacity compared with the Amit-Gutfreund-Sompolinsky (AGS) value: with decreasing θ from θ=∞, the storage capacity αc of such a network is increased from the AGS value (~=0.14) to attain its maximum value of ~=0.42 at θ~=0.7 and afterwards is decreased to vanish at θ=0. Whereas for θ>~1 the storage capacity αc coincides with the value αc~ determined by the SCSNA as the upper bound of α ensuring the existence of retrieval solutions, for θ<~1 the αc is shown to differ from the αc~ with the result that the retrieval solutions claimed by the SCSNA are unstable for αc<α<αc~. Second, in the case of θ<1 the network can exhibit a new type of phase which appears as a result of a phase transition with respect to the non-Gaussian distribution of the local fields of neurons: the standard type of retrieval state with r≠0 (i.e., finite width of the local field distribution), which is implied by the order-parameter equations of the SCSNA, disappears at a certain critical loading rate α0, and for α<=α0 a qualitatively different type of retrieval state comes into existence in which the width of the local field distribution vanishes (i.e., r=0+). As a consequence, memory retrieval without errors becomes possible even in the saturation limit α≠0. Results of the computer simulations on the statistical properties of the novel phase with α<=α0 are shown to be in satisfactory agreement with the theoretical results. The effect of introducing self-couplings on the storage capacity is also analyzed for the two types of networks. It is conspicuous for the networks with FNM, where the self-couplings increase the stability of the retrieval solutions of the SCSNA with small values of θ, leading to a remarkable enhancement of the storage capacity.

Storage of RF photons in minimal conditions

NASA Astrophysics Data System (ADS)

Cromières, J.-P.; Chanelière, T.

2018-02-01

We investigate the minimal conditions to store coherently a RF pulse in a material medium. We choose a commercial quartz as a memory support because it is a widely available component with a high Q-factor. Pulse storage is obtained by varying dynamically the light-matter coupling with an analog switch. This parametric driving of the quartz dynamics can be alternatively interpreted as a stopped-light experiment. We obtain an efficiency of 26%, a storage time of 209 μs and a time-to-bandwidth product of 98 by optimizing the pulse temporal shape. The coherent character of the storage is demonstrated. Our goal is to connect different types of memories in the RF and optical domain for quantum information processing. Our motivation is essentially fundamental.

Application-Controlled Demand Paging for Out-of-Core Visualization

NASA Technical Reports Server (NTRS)

Cox, Michael; Ellsworth, David; Kutler, Paul (Technical Monitor)

1997-01-01

In the area of scientific visualization, input data sets are often very large. In visualization of Computational Fluid Dynamics (CFD) in particular, input data sets today can surpass 100 Gbytes, and are expected to scale with the ability of supercomputers to generate them. Some visualization tools already partition large data sets into segments, and load appropriate segments as they are needed. However, this does not remove the problem for two reasons: 1) there are data sets for which even the individual segments are too large for the largest graphics workstations, 2) many practitioners do not have access to workstations with the memory capacity required to load even a segment, especially since the state-of-the-art visualization tools tend to be developed by researchers with much more powerful machines. When the size of the data that must be accessed is larger than the size of memory, some form of virtual memory is simply required. This may be by segmentation, paging, or by paged segments. In this paper we demonstrate that complete reliance on operating system virtual memory for out-of-core visualization leads to poor performance. We then describe a paged segment system that we have implemented, and explore the principles of memory management that can be employed by the application for out-of-core visualization. We show that application control over some of these can significantly improve performance. We show that sparse traversal can be exploited by loading only those data actually required. We show also that application control over data loading can be exploited by 1) loading data from alternative storage format (in particular 3-dimensional data stored in sub-cubes), 2) controlling the page size. Both of these techniques effectively reduce the total memory required by visualization at run-time. We also describe experiments we have done on remote out-of-core visualization (when pages are read by demand from remote disk) whose results are promising.

Toward Transparent Data Management in Multi-layer Storage Hierarchy for HPC Systems

DOE PAGES

Wadhwa, Bharti; Byna, Suren; Butt, Ali R.

2018-04-17

Upcoming exascale high performance computing (HPC) systems are expected to comprise multi-tier storage hierarchy, and thus will necessitate innovative storage and I/O mechanisms. Traditional disk and block-based interfaces and file systems face severe challenges in utilizing capabilities of storage hierarchies due to the lack of hierarchy support and semantic interfaces. Object-based and semantically-rich data abstractions for scientific data management on large scale systems offer a sustainable solution to these challenges. Such data abstractions can also simplify users involvement in data movement. Here, we take the first steps of realizing such an object abstraction and explore storage mechanisms for these objectsmore » to enhance I/O performance, especially for scientific applications. We explore how an object-based interface can facilitate next generation scalable computing systems by presenting the mapping of data I/O from two real world HPC scientific use cases: a plasma physics simulation code (VPIC) and a cosmology simulation code (HACC). Our storage model stores data objects in different physical organizations to support data movement across layers of memory/storage hierarchy. Our implementation sclaes well to 16K parallel processes, and compared to the state of the art, such as MPI-IO and HDF5, our object-based data abstractions and data placement strategy in multi-level storage hierarchy achieves up to 7 X I/O performance improvement for scientific data.« less

Toward Transparent Data Management in Multi-layer Storage Hierarchy for HPC Systems

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wadhwa, Bharti; Byna, Suren; Butt, Ali R.

Upcoming exascale high performance computing (HPC) systems are expected to comprise multi-tier storage hierarchy, and thus will necessitate innovative storage and I/O mechanisms. Traditional disk and block-based interfaces and file systems face severe challenges in utilizing capabilities of storage hierarchies due to the lack of hierarchy support and semantic interfaces. Object-based and semantically-rich data abstractions for scientific data management on large scale systems offer a sustainable solution to these challenges. Such data abstractions can also simplify users involvement in data movement. Here, we take the first steps of realizing such an object abstraction and explore storage mechanisms for these objectsmore » to enhance I/O performance, especially for scientific applications. We explore how an object-based interface can facilitate next generation scalable computing systems by presenting the mapping of data I/O from two real world HPC scientific use cases: a plasma physics simulation code (VPIC) and a cosmology simulation code (HACC). Our storage model stores data objects in different physical organizations to support data movement across layers of memory/storage hierarchy. Our implementation sclaes well to 16K parallel processes, and compared to the state of the art, such as MPI-IO and HDF5, our object-based data abstractions and data placement strategy in multi-level storage hierarchy achieves up to 7 X I/O performance improvement for scientific data.« less

Optimal Recall from Bounded Metaplastic Synapses: Predicting Functional Adaptations in Hippocampal Area CA3

PubMed Central

Savin, Cristina; Dayan, Peter; Lengyel, Máté

2014-01-01

A venerable history of classical work on autoassociative memory has significantly shaped our understanding of several features of the hippocampus, and most prominently of its CA3 area, in relation to memory storage and retrieval. However, existing theories of hippocampal memory processing ignore a key biological constraint affecting memory storage in neural circuits: the bounded dynamical range of synapses. Recent treatments based on the notion of metaplasticity provide a powerful model for individual bounded synapses; however, their implications for the ability of the hippocampus to retrieve memories well and the dynamics of neurons associated with that retrieval are both unknown. Here, we develop a theoretical framework for memory storage and recall with bounded synapses. We formulate the recall of a previously stored pattern from a noisy recall cue and limited-capacity (and therefore lossy) synapses as a probabilistic inference problem, and derive neural dynamics that implement approximate inference algorithms to solve this problem efficiently. In particular, for binary synapses with metaplastic states, we demonstrate for the first time that memories can be efficiently read out with biologically plausible network dynamics that are completely constrained by the synaptic plasticity rule, and the statistics of the stored patterns and of the recall cue. Our theory organises into a coherent framework a wide range of existing data about the regulation of excitability, feedback inhibition, and network oscillations in area CA3, and makes novel and directly testable predictions that can guide future experiments. PMID:24586137

Amygdala's involvement in facilitating associative learning-induced plasticity: a promiscuous role for the amygdala in memory acquisition

PubMed Central

Chau, Lily S.; Galvez, Roberto

2012-01-01

It is widely accepted that the amygdala plays a critical role in acquisition and consolidation of fear-related memories. Some of the more widely employed behavioral paradigms that have assisted in solidifying the amygdala's role in fear-related memories are associative learning paradigms. With most associative learning tasks, a neutral conditioned stimulus (CS) is paired with a salient unconditioned stimulus (US) that elicits an unconditioned response (UR). After multiple CS-US pairings, the subject learns that the CS predicts the onset or delivery of the US, and thus elicits a learned conditioned response (CR). Most fear-related associative paradigms have suggested that an aspect of the fear association is stored in the amygdala; however, some fear-motivated associative paradigms suggest that the amygdala is not a site of storage, but rather facilitates consolidation in other brain regions. Based upon various learning theories, one of the most likely sites for storage of long-term memories is the neocortex. In support of these theories, findings from our laboratory, and others, have demonstrated that trace-conditioning, an associative paradigm where there is a separation in time between the CS and US, induces learning-specific neocortical plasticity. The following review will discuss the amygdala's involvement, either as a site of storage or facilitating storage in other brain regions such as the neocortex, in fear- and non-fear-motivated associative paradigms. In this review, we will discuss recent findings suggesting a broader role for the amygdala in increasing the saliency of behaviorally relevant information, thus facilitating acquisition for all forms of memory, both fear- and non-fear-related. This proposed promiscuous role of the amygdala in facilitating acquisition for all memories further suggests a potential role of the amygdala in general learning disabilities. PMID:23087626

Amygdala's involvement in facilitating associative learning-induced plasticity: a promiscuous role for the amygdala in memory acquisition.

PubMed

Chau, Lily S; Galvez, Roberto

2012-01-01

It is widely accepted that the amygdala plays a critical role in acquisition and consolidation of fear-related memories. Some of the more widely employed behavioral paradigms that have assisted in solidifying the amygdala's role in fear-related memories are associative learning paradigms. With most associative learning tasks, a neutral conditioned stimulus (CS) is paired with a salient unconditioned stimulus (US) that elicits an unconditioned response (UR). After multiple CS-US pairings, the subject learns that the CS predicts the onset or delivery of the US, and thus elicits a learned conditioned response (CR). Most fear-related associative paradigms have suggested that an aspect of the fear association is stored in the amygdala; however, some fear-motivated associative paradigms suggest that the amygdala is not a site of storage, but rather facilitates consolidation in other brain regions. Based upon various learning theories, one of the most likely sites for storage of long-term memories is the neocortex. In support of these theories, findings from our laboratory, and others, have demonstrated that trace-conditioning, an associative paradigm where there is a separation in time between the CS and US, induces learning-specific neocortical plasticity. The following review will discuss the amygdala's involvement, either as a site of storage or facilitating storage in other brain regions such as the neocortex, in fear- and non-fear-motivated associative paradigms. In this review, we will discuss recent findings suggesting a broader role for the amygdala in increasing the saliency of behaviorally relevant information, thus facilitating acquisition for all forms of memory, both fear- and non-fear-related. This proposed promiscuous role of the amygdala in facilitating acquisition for all memories further suggests a potential role of the amygdala in general learning disabilities.

Sleeping in a Brave New World: Opportunities for Improving Learning and Clinical Outcomes through Targeted Memory Reactivation.

PubMed

Paller, Ken A

2017-12-01

Neuroscientific insights into learning and memory have mostly concerned input and output, but intervening processing during the time between acquisition and retrieval is also critical. Indeed, intervening memory reactivation may regulate memory longevity, and a growing body of evidence implicates sleep in changing memory storage. For example, subtle auditory stimulation can be used experimentally to selectively encourage memory reactivation during sleep, which thereby improves learning. Much remains to be elucidated about how learning depends on sleep. Nevertheless, this methodology for modifying memory storage during sleep offers new opportunities for reinforcing learning to enhance clinical outcomes in conjunction with therapies engaged during waking. A variety of such possibilities must now be carefully investigated. Likewise, brain rhythms can be entrained to enhance sleep functions, facilitating further progress in understanding the neurophysiological basis of memory processing during sleep. Ultimately, empirical evidence may reveal the extent to which the way we behave when awake is a function of what our brains do when we are asleep. Through such research efforts, an advanced understanding of memory and sleep may allow us to both make better use of our time asleep and take steps toward better health.

Re-evaluating the relationships among filtering activity, unnecessary storage, and visual working memory capacity.

PubMed

Emrich, Stephen M; Busseri, Michael A

2015-09-01

The amount of task-irrelevant information encoded in visual working memory (VWM), referred to as unnecessary storage, has been proposed as a potential mechanism underlying individual differences in VWM capacity. In addition, a number of studies have provided evidence for additional activity that initiates the filtering process originating in the frontal cortex and basal ganglia, and is therefore a crucial step in the link between unnecessary storage and VWM capacity. Here, we re-examine data from two prominent studies that identified unnecessary storage activity as a predictor of VWM capacity by directly testing the implied path model linking filtering-related activity, unnecessary storage, and VWM capacity. Across both studies, we found that unnecessary storage was not a significant predictor of individual differences in VWM capacity once activity associated with filtering was accounted for; instead, activity associated with filtering better explained variation in VWM capacity. These findings suggest that unnecessary storage is not a limiting factor in VWM performance, whereas neural activity associated with filtering may play a more central role in determining VWM performance that goes beyond preventing unnecessary storage.

The Construction of Semantic Memory: Grammar-Based Representations Learned from Relational Episodic Information

PubMed Central

Battaglia, Francesco P.; Pennartz, Cyriel M. A.

2011-01-01

After acquisition, memories underlie a process of consolidation, making them more resistant to interference and brain injury. Memory consolidation involves systems-level interactions, most importantly between the hippocampus and associated structures, which takes part in the initial encoding of memory, and the neocortex, which supports long-term storage. This dichotomy parallels the contrast between episodic memory (tied to the hippocampal formation), collecting an autobiographical stream of experiences, and semantic memory, a repertoire of facts and statistical regularities about the world, involving the neocortex at large. Experimental evidence points to a gradual transformation of memories, following encoding, from an episodic to a semantic character. This may require an exchange of information between different memory modules during inactive periods. We propose a theory for such interactions and for the formation of semantic memory, in which episodic memory is encoded as relational data. Semantic memory is modeled as a modified stochastic grammar, which learns to parse episodic configurations expressed as an association matrix. The grammar produces tree-like representations of episodes, describing the relationships between its main constituents at multiple levels of categorization, based on its current knowledge of world regularities. These regularities are learned by the grammar from episodic memory information, through an expectation-maximization procedure, analogous to the inside–outside algorithm for stochastic context-free grammars. We propose that a Monte-Carlo sampling version of this algorithm can be mapped on the dynamics of “sleep replay” of previously acquired information in the hippocampus and neocortex. We propose that the model can reproduce several properties of semantic memory such as decontextualization, top-down processing, and creation of schemata. PMID:21887143

Elements of the cellular metabolic structure

PubMed Central

De la Fuente, Ildefonso M.

2015-01-01

A large number of studies have demonstrated the existence of metabolic covalent modifications in different molecular structures, which are able to store biochemical information that is not encoded by DNA. Some of these covalent mark patterns can be transmitted across generations (epigenetic changes). Recently, the emergence of Hopfield-like attractor dynamics has been observed in self-organized enzymatic networks, which have the capacity to store functional catalytic patterns that can be correctly recovered by specific input stimuli. Hopfield-like metabolic dynamics are stable and can be maintained as a long-term biochemical memory. In addition, specific molecular information can be transferred from the functional dynamics of the metabolic networks to the enzymatic activity involved in covalent post-translational modulation, so that determined functional memory can be embedded in multiple stable molecular marks. The metabolic dynamics governed by Hopfield-type attractors (functional processes), as well as the enzymatic covalent modifications of specific molecules (structural dynamic processes) seem to represent the two stages of the dynamical memory of cellular metabolism (metabolic memory). Epigenetic processes appear to be the structural manifestation of this cellular metabolic memory. Here, a new framework for molecular information storage in the cell is presented, which is characterized by two functionally and molecularly interrelated systems: a dynamic, flexible and adaptive system (metabolic memory) and an essentially conservative system (genetic memory). The molecular information of both systems seems to coordinate the physiological development of the whole cell. PMID:25988183

Durability of carbon fiber reinforced shape memory polymer composites in space

NASA Astrophysics Data System (ADS)

Jang, Joon Hyeok; Hong, Seok Bin; Ahn, Yong San; Kim, Jin-Gyun; Nam, Yong-Youn; Lee, Geun Ho; Yu, Woong-Ryeol

2016-04-01

Shape memory polymer (SMP) is one of smart polymers which exhibit shape memory effect upon external stimuli. Recently, shape memory polymer composites (SMPCs) have been considered for space structure instead of shape memory alloys due to their deformability, lightweight and large recovery ratio, requiring characterization of their mechanical properties against harsh space environment and further prediction of the durability of SMPCs in space. As such, the durability of carbon fiber reinforced shape memory polymer composites (CF-SMPCs) was investigated using accelerated testing method based on short-term testing of CF-SMPCs in harsh condition. CF-SMPCs were prepared using woven carbon fabrics and a thermoset SMP via vacuum assisted resin transfer molding process. Bending tests with constant strain rate of CF-SMPCs were conducted using universal tensile machine (UTM) and Storage modulus test were conducted using dynamic mechanical thermal analysis (DMTA). Using the results, a master curve based on time-temperature superposition principle was then constructed, through which the mechanical properties of CF-SMPCs at harsh temperature were predicted. CF-SMPCs would be exposed to simulated space environments under ultra-violet radiations at various temperatures. The mechanical properties including flexural and tensile strength and shape memory properties of SMPCs would be measured using UTM before and after such exposures for comparison. Finally, the durability of SMPCs in space would be assessed by developing a degradation model of SMPC.

Inefficient Executive Cognitive Control in Schizophrenia Is Preceded by Altered Functional Activation during Information Encoding: An fMRI Study

ERIC Educational Resources Information Center

Schlosser, Ralf G. M.; Koch, Kathrin; Wagner, Gerd; Nenadic, Igor; Roebel, Martin; Schachtzabel, Claudia; Axer, Martina; Schultz, Christoph; Reichenbach, Jurgen R.; Sauer, Heinrich

2008-01-01

Working memory deficits are a core feature of schizophrenia. Previous working memory studies suggest a load dependent storage deficit. However, explicit studies of higher executive working memory processes are limited. Moreover, few studies have examined whether subcomponents of working memory such as encoding and maintenance of information are…

Protein Synthesis Underlies Post-Retrieval Memory Consolidation to a Restricted Degree Only when Updated Information Is Obtained

ERIC Educational Resources Information Center

Rodriguez-Ortiz, Carlos J.; De la Cruz, Vanesa; Gutierrez, Ranier; Bermudez-Rattoni, Federico

2005-01-01

Consolidation theory proposes that through the synthesis of new proteins recently acquired memories are strengthened over time into a stable long-term memory trace. However, evidence has accumulated suggesting that retrieved memory is susceptible to disruption, seeming to consolidate again (reconsolidate) to be retained in long-term storage. Here…

Formation of SiGe nanocrystals embedded in Al{sub 2}O{sub 3} for the application of write-once-read-many-times memory

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Min-Lin; Wu, Yung-Hsien; Lin, Chia-Chun

2012-10-15

The structure of SiGe nanocrystals embedded in Al{sub 2}O{sub 3} formed by sequential deposition of Al{sub 2}O{sub 3}/Si/Ge/Al{sub 2}O{sub 3} and a subsequent annealing was confirmed by transmission electron microscopy and energy dispersive spectroscopy (EDS), and its application for write-once-read-many-times (WORM) memory devices was explored in this study. By applying a -10 V pulse for 1 s, a large amount of holes injected from Si substrate are stored in the nanocrystals and consequently, the current at +1.5 V increases by a factor of 10{sup 4} as compared to that of the initial state. Even with a smaller -5 V pulsemore » for 1 {mu}s, a sufficiently large current ratio of 36 can still be obtained, verifying the low power operation. Since holes are stored in nanocrystals which are isolated from Si substrate by Al{sub 2}O{sub 3} with good integrity and correspond to a large valence band offset with respect to Al{sub 2}O{sub 3}, desirable read endurance up to 10{sup 5} cycles and excellent retention over 100 yr are achieved. Combining these promising characteristics, WORM memory devices are appropriate for high-performance archival storage applications.« less

Memory characteristics of metal-oxide-semiconductor structures based on Ge nanoclusters-embedded GeO(x) films grown at low temperature.

PubMed

Lin, Tzu-Shun; Lou, Li-Ren; Lee, Ching-Ting; Tsai, Tai-Cheng

2012-03-01

The memory devices constructed from the Ge-nanoclusters embedded GeO(x) layer deposited by the laser-assisted chemical vapor deposition (LACVD) system were fabricated. The Ge nanoclusters were observed by a high-resolution transmission electron microscopy. Using the capacitance versus voltage (C-V) and the conductance versus voltage (G-V) characteristics measured under various frequencies, the memory effect observed in the C-V curves was dominantly attributed to the charge storage in the Ge nanoclusters. Furthermore, the defects existed in the deposited film and the interface states were insignificant to the memory performances. Capacitance versus time (C-t) measurement was also executed to evaluate the charge retention characteristics. The charge storage and retention behaviors of the devices demonstrated that the Ge nanoclusters grown by the LACVD system at low temperature are promising for memory device applications.

Effect with high density nano dot type storage layer structure on 20 nm planar NAND flash memory characteristics

NASA Astrophysics Data System (ADS)

Sasaki, Takeshi; Muraguchi, Masakazu; Seo, Moon-Sik; Park, Sung-kye; Endoh, Tetsuo

2014-01-01

The merits, concerns and design principle for the future nano dot (ND) type NAND flash memory cell are clarified, by considering the effect of storage layer structure on NAND flash memory characteristics. The characteristics of the ND cell for a NAND flash memory in comparison with the floating gate type (FG) is comprehensively studied through the read, erase, program operation, and the cell to cell interference with device simulation. Although the degradation of the read throughput (0.7% reduction of the cell current) and slower program time (26% smaller programmed threshold voltage shift) with high density (10 × 1012 cm-2) ND NAND are still concerned, the suppress of the cell to cell interference with high density (10 × 1012 cm-2) plays the most important part for scaling and multi-level cell (MLC) operation in comparison with the FG NAND. From these results, the design knowledge is shown to require the control of the number of nano dots rather than the higher nano dot density, from the viewpoint of increasing its memory capacity by MLC operation and suppressing threshold voltage variability caused by the number of dots in the storage layer. Moreover, in order to increase its memory capacity, it is shown the tunnel oxide thickness with ND should be designed thicker (>3 nm) than conventional designed ND cell for programming/erasing with direct tunneling mechanism.

Garnet Random-Access Memory

NASA Technical Reports Server (NTRS)

Katti, Romney R.

1995-01-01

Random-access memory (RAM) devices of proposed type exploit magneto-optical properties of magnetic garnets exhibiting perpendicular anisotropy. Magnetic writing and optical readout used. Provides nonvolatile storage and resists damage by ionizing radiation. Because of basic architecture and pinout requirements, most likely useful as small-capacity memory devices.

Persistent neural activity in auditory cortex is related to auditory working memory in humans and nonhuman primates

PubMed Central

Huang, Ying; Matysiak, Artur; Heil, Peter; König, Reinhard; Brosch, Michael

2016-01-01

Working memory is the cognitive capacity of short-term storage of information for goal-directed behaviors. Where and how this capacity is implemented in the brain are unresolved questions. We show that auditory cortex stores information by persistent changes of neural activity. We separated activity related to working memory from activity related to other mental processes by having humans and monkeys perform different tasks with varying working memory demands on the same sound sequences. Working memory was reflected in the spiking activity of individual neurons in auditory cortex and in the activity of neuronal populations, that is, in local field potentials and magnetic fields. Our results provide direct support for the idea that temporary storage of information recruits the same brain areas that also process the information. Because similar activity was observed in the two species, the cellular bases of some auditory working memory processes in humans can be studied in monkeys. DOI: http://dx.doi.org/10.7554/eLife.15441.001 PMID:27438411

Configurable memory system and method for providing atomic counting operations in a memory device

DOEpatents

Bellofatto, Ralph E.; Gara, Alan G.; Giampapa, Mark E.; Ohmacht, Martin

2010-09-14

A memory system and method for providing atomic memory-based counter operations to operating systems and applications that make most efficient use of counter-backing memory and virtual and physical address space, while simplifying operating system memory management, and enabling the counter-backing memory to be used for purposes other than counter-backing storage when desired. The encoding and address decoding enabled by the invention provides all this functionality through a combination of software and hardware.

Deformation behavior of carbon-fiber reinforced shape-memory-polymer composites used for deployable structures (Conference Presentation)

NASA Astrophysics Data System (ADS)

Lan, Xin; Liu, Liwu; Li, Fengfeng; Pan, Chengtong; Liu, Yanju; Leng, Jinsong

2017-04-01

Shape memory polymers (SMPs) are a new type of smart material, they perform large reversible deformation with a certain external stimulus (e.g., heat and electricity). The properties (e.g., stiffness, strength and other mechanically static or quasi-static load-bearing capacity) are primarily considered for conventional resin-based composite materials which are mainly used for structural materials. By contrast, the mechanical actuating performance with finite deformation is considered for the shape memory polymers and their composites which can be used for both structural materials and functional materials. For shape memory polymers and their composites, the performance of active deformation is expected to further promote the development in smart active deformation structures, such as deployable space structures and morphing wing aircraft. The shape memory polymer composites (SMPCs) are also one type of High Strain Composite (HSC). The space deployable structures based on carbon fiber reinforced shape memory polymer composites (SMPCs) show great prospects. Considering the problems that SMPCs are difficult to meet the practical applications in space deployable structures in the recent ten years, this paper aims to research the mechanics of deformation, actuation and failure of SMPCs. In the overall view of the shape memory polymer material's nonlinearity (nonlinearity and stress softening in the process of pre-deformation and recovery, relaxation in storage process, irreversible deformation), by the multiple verifications among theory, finite element and experiments, one obtains the deformation and actuation mechanism for the process of "pre-deformation, energy storage and actuation" and its non-fracture constraint domain. Then, the parameters of SMPCs will be optimized. Theoretical analysis is realized by the strain energy function, additionally considering the interaction strain energy between the fiber and the matrix. For the common resin-based or soft-material-based composites under pure bending deformation, we expect to uniformly explain the whole process of buckling occurrence, evolution and finally failure, especially for the early evolution characteristics of fiber microbuckling inside the microstructures. The research results are meaningful for the practical applications for SMPC deployable structures in space. Considering the deformation mechanisms of SMPCs, the local post-microbuckling is required for the unidirectional fiber reinforced composite materials, at the conditions of its large geometrical deflection. The cross section of SMPC is divided into three areas: non-buckling stretching area, non-buckling compressive area, and buckling compressive area. Three variables are considered: critical buckling position, and neutral plane, the fiber buckling half-wavelength. Considering the condition of the small strain and large displacement, the strain energy expression of the SMP/fiber system was derived, which contains two types, e.g., strain energy of SMP and fiber. According to the minimum energy principle, the expression for all key parameters were derived, including the critical buckling curvature, neutral plane position, the buckling half-wavelength, fiber buckling amplitude, and strain.

A Cache Design to Exploit Structural Locality

DTIC Science & Technology

1991-12-01

memory and secondary storage. Main memory was used to store the instructions and data of an executing pro- gram, while secondary storage held programs ...efficiency of the CPU and faster turnaround of executing programs . In addition to the well known spatial and temporal aspects of locality, Hobart has...identified a third aspect, which he has called structural locality (9). This type of locality is defined as the tendency of an executing program to

Digitally programmable signal generator and method

DOEpatents

Priatko, G.J.; Kaskey, J.A.

1989-11-14

Disclosed is a digitally programmable waveform generator for generating completely arbitrary digital or analog waveforms from very low frequencies to frequencies in the gigasample per second range. A memory array with multiple parallel outputs is addressed; then the parallel output data is latched into buffer storage from which it is serially multiplexed out at a data rate many times faster than the access time of the memory array itself. While data is being multiplexed out serially, the memory array is accessed with the next required address and presents its data to the buffer storage before the serial multiplexing of the last group of data is completed, allowing this new data to then be latched into the buffer storage for smooth continuous serial data output. In a preferred implementation, a plurality of these serial data outputs are paralleled to form the input to a digital to analog converter, providing a programmable analog output. 6 figs.

Digitally programmable signal generator and method

DOEpatents

Priatko, Gordon J.; Kaskey, Jeffrey A.

1989-01-01

A digitally programmable waveform generator for generating completely arbitrary digital or analog waveforms from very low frequencies to frequencies in the gigasample per second range. A memory array with multiple parallel outputs is addressed; then the parallel output data is latched into buffer storage from which it is serially multiplexed out at a data rate many times faster than the access time of the memory array itself. While data is being multiplexed out serially, the memory array is accessed with the next required address and presents its data to the buffer storage before the serial multiplexing of the last group of data is completed, allowing this new data to then be latched into the buffer storage for smooth continuous serial data output. In a preferred implementation, a plurality of these serial data outputs are paralleled to form the input to a digital to analog converter, providing a programmable analog output.

Room Temperature Memory for Few Photon Polarization Qubits

NASA Astrophysics Data System (ADS)

Kupchak, Connor; Mittiga, Thomas; Jordan, Bertus; Nazami, Mehdi; Nolleke, Christian; Figueroa, Eden

2014-05-01

We have developed a room temperature quantum memory device based on Electromagnetically Induced Transparency capable of reliably storing and retrieving polarization qubits on the few photon level. Our system is realized in a vapor of 87Rb atoms utilizing a Λ-type energy level scheme. We create a dual-rail storage scheme mediated by an intense control field to allow storage and retrieval of any arbitrary polarization state. Upon retrieval, we employ a filtering system to sufficiently remove the strong pump field, and subject retrieved light states to polarization tomography. To date, our system has produced signal-to-noise ratios near unity with a memory fidelity of >80 % using coherent state qubits containing four photons on average. Our results thus demonstrate the feasibility of room temperature systems for the storage of single-photon-level photonic qubits. Such room temperature systems will be attractive for future long distance quantum communication schemes.

North by Northwestern: initial experience with PACS at Northwestern Memorial Hospital

NASA Astrophysics Data System (ADS)

Channin, David S.; Hawkins, Rodney C.; Enzmann, Dieter R.

2000-05-01

This paper describes the initial phases and configuration of the Picture Archive and Communication System (PACS) deployed at Northwestern Memorial Hospital. The primary goals of the project were to improve service to patients, improve service to referring physicians, and improve the process of radiology. Secondary goals were to enhance the academic mission, and modernize institutional information systems. The system consists of a large number of heterogeneous imaging modalities sending imaging studies via DICOM to a GE medical Systems PathSpeed PACS. The radiology department workflow is briefly described. The system is currently storing approximately 140,000 studies and over 5 million images, growing by approximately 600 studies and 25,000 images per day. Data reflecting use of the short term and long term storage is provided.

Topological computation based on direct magnetic logic communication.

PubMed

Zhang, Shilei; Baker, Alexander A; Komineas, Stavros; Hesjedal, Thorsten

2015-10-28

Non-uniform magnetic domains with non-trivial topology, such as vortices and skyrmions, are proposed as superior state variables for nonvolatile information storage. So far, the possibility of logic operations using topological objects has not been considered. Here, we demonstrate numerically that the topology of the system plays a significant role for its dynamics, using the example of vortex-antivortex pairs in a planar ferromagnetic film. Utilising the dynamical properties and geometrical confinement, direct logic communication between the topological memory carriers is realised. This way, no additional magnetic-to-electrical conversion is required. More importantly, the information carriers can spontaneously travel up to ~300 nm, for which no spin-polarised current is required. The derived logic scheme enables topological spintronics, which can be integrated into large-scale memory and logic networks capable of complex computations.

An Investigation of Quantum Dot Super Lattice Use in Nonvolatile Memory and Transistors

NASA Astrophysics Data System (ADS)

Mirdha, P.; Parthasarathy, B.; Kondo, J.; Chan, P.-Y.; Heller, E.; Jain, F. C.

2018-02-01

Site-specific self-assembled colloidal quantum dots (QDs) will deposit in two layers only on p-type substrate to form a QD superlattice (QDSL). The QDSL structure has been integrated into the floating gate of a nonvolatile memory component and has demonstrated promising results in multi-bit storage, ease of fabrication, and memory retention. Additionally, multi-valued logic devices and circuits have been created by using QDSL structures which demonstrated ternary and quaternary logic. With increasing use of site-specific self-assembled QDSLs, fundamental understanding of silicon and germanium QDSL charge storage capability, self-assembly on specific surfaces, uniform distribution, and mini-band formation has to be understood for successful implementation in devices. In this work, we investigate the differences in electron charge storage by building metal-oxide semiconductor (MOS) capacitors and using capacitance and voltage measurements to quantify the storage capabilities. The self-assembly process and distribution density of the QDSL is done by obtaining atomic force microscopy (AFM) results on line samples. Additionally, we present a summary of the theoretical density of states in each of the QDSLs.

Low-Storage, Explicit Runge-Kutta Schemes for the Compressible Navier-Stokes Equations

NASA Technical Reports Server (NTRS)

Kennedy, Chistopher A.; Carpenter, Mark H.; Lewis, R. Michael

1999-01-01

The derivation of storage explicit Runge-Kutta (ERK) schemes has been performed in the context of integrating the compressible Navier-Stokes equations via direct numerical simulation. Optimization of ERK methods is done across the broad range of properties, such as stability and accuracy efficiency, linear and nonlinear stability, error control reliability, step change stability, and dissipation/dispersion accuracy, subject to varying degrees of memory economization. Following van der Houwen and Wray, 16 ERK pairs are presented using from two to five registers of memory per equation, per grid point and having accuracies from third- to fifth-order. Methods have been assessed using the differential equation testing code DETEST, and with the 1D wave equation. Two of the methods have been applied to the DNS of a compressible jet as well as methane-air and hydrogen-air flames. Derived 3(2) and 4(3) pairs are competitive with existing full-storage methods. Although a substantial efficiency penalty accompanies use of two- and three-register, fifth-order methods, the best contemporary full-storage methods can be pearl), matched while still saving two to three registers of memory.

Two Equals One: Two Human Actions During Social Interaction Are Grouped as One Unit in Working Memory.

PubMed

Ding, Xiaowei; Gao, Zaifeng; Shen, Mowei

2017-09-01

Every day, people perceive other people performing interactive actions. Retaining these actions of human agents in working memory (WM) plays a pivotal role in a normal social life. However, whether the semantic knowledge embedded in the interactive actions has a pervasive impact on the storage of the actions in WM remains unknown. In the current study, we investigated two opposing hypotheses: (a) that WM stores the interactions individually (the individual-storage hypothesis) and (b) that WM stores the interactions as chunks (the chunk-storage hypothesis). We required participants to memorize a set of individual actions while ignoring the underlying social interactions. We found that although the social-interaction aspect was task irrelevant, the interactive actions were stored in WM as chunks that were not affected by memory load (Experiments 1 and 2); however, inverting the human actions vertically abolished this chunking effect (Experiment 3). These results suggest that WM automatically and efficiently used semantic knowledge about interactive actions to store them and support the chunk-storage hypothesis.

Strategic trade-offs between quality and quantity in working memory

PubMed Central

Fougnie, Daryl; Cormiea, Sarah M.; Kanabar, Anish; Alvarez, George A.

2016-01-01

Is working memory capacity determined by an immutable limit—e.g. four memory storage slots? The fact that performance is typically unaffected by task instructions has been taken as support for such structural models of memory. Here, we modified a standard working memory task to incentivize participants to remember more items. Participants were asked to remember a set of colors over a short retention interval. In one condition, participants reported a random item’s color using a color wheel. In the modified task, participants responded to all items and their response was only considered correct if all responses were on the correct half of the color wheel. We looked for a trade-off between quantity and quality—participants storing more items, but less precisely, when required to report them all. This trade-off was observed when tasks were blocked, when task-type was cued after encoding, but not when task-type was cued during the response, suggesting that task differences changed how items were actively encoded and maintained. This strategic control over the contents of working memory challenges models that assume inflexible limits on memory storage. PMID:26950383

A neural measure of precision in visual working memory.

PubMed

Ester, Edward F; Anderson, David E; Serences, John T; Awh, Edward

2013-05-01

Recent studies suggest that the temporary storage of visual detail in working memory is mediated by sensory recruitment or sustained patterns of stimulus-specific activation within feature-selective regions of visual cortex. According to a strong version of this hypothesis, the relative "quality" of these patterns should determine the clarity of an individual's memory. Here, we provide a direct test of this claim. We used fMRI and a forward encoding model to characterize population-level orientation-selective responses in visual cortex while human participants held an oriented grating in memory. This analysis, which enables a precise quantitative description of multivoxel, population-level activity measured during working memory storage, revealed graded response profiles whose amplitudes were greatest for the remembered orientation and fell monotonically as the angular distance from this orientation increased. Moreover, interparticipant differences in the dispersion-but not the amplitude-of these response profiles were strongly correlated with performance on a concurrent memory recall task. These findings provide important new evidence linking the precision of sustained population-level responses in visual cortex and memory acuity.

Visual and spatial working memory are not that dissociated after all: a time-based resource-sharing account.

PubMed

Vergauwe, Evie; Barrouillet, Pierre; Camos, Valérie

2009-07-01

Examinations of interference between visual and spatial materials in working memory have suggested domain- and process-based fractionations of visuo-spatial working memory. The present study examined the role of central time-based resource sharing in visuo-spatial working memory and assessed its role in obtained interference patterns. Visual and spatial storage were combined with both visual and spatial on-line processing components in computer-paced working memory span tasks (Experiment 1) and in a selective interference paradigm (Experiment 2). The cognitive load of the processing components was manipulated to investigate its impact on concurrent maintenance for both within-domain and between-domain combinations of processing and storage components. In contrast to both domain- and process-based fractionations of visuo-spatial working memory, the results revealed that recall performance was determined by the cognitive load induced by the processing of items, rather than by the domain to which those items pertained. These findings are interpreted as evidence for a time-based resource-sharing mechanism in visuo-spatial working memory.

Sequence memory based on coherent spin-interaction neural networks.

PubMed

Xia, Min; Wong, W K; Wang, Zhijie

2014-12-01

Sequence information processing, for instance, the sequence memory, plays an important role on many functions of brain. In the workings of the human brain, the steady-state period is alterable. However, in the existing sequence memory models using heteroassociations, the steady-state period cannot be changed in the sequence recall. In this work, a novel neural network model for sequence memory with controllable steady-state period based on coherent spininteraction is proposed. In the proposed model, neurons fire collectively in a phase-coherent manner, which lets a neuron group respond differently to different patterns and also lets different neuron groups respond differently to one pattern. The simulation results demonstrating the performance of the sequence memory are presented. By introducing a new coherent spin-interaction sequence memory model, the steady-state period can be controlled by dimension parameters and the overlap between the input pattern and the stored patterns. The sequence storage capacity is enlarged by coherent spin interaction compared with the existing sequence memory models. Furthermore, the sequence storage capacity has an exponential relationship to the dimension of the neural network.

A Synaptic Basis for Memory Storage in the Cerebral Cortex

NASA Astrophysics Data System (ADS)

Bear, Mark F.

1996-11-01

A cardinal feature of neurons in the cerebral cortex is stimulus selectivity, and experience-dependent shifts in selectivity are a common correlate of memory formation. We have used a theoretical ``learning rule,'' devised to account for experience-dependent shifts in neuronal selectivity, to guide experiments on the elementary mechanisms of synaptic plasticity in hippocampus and neocortex. These experiments reveal that many synapses in hippocampus and neocortex are bidirectionally modifiable, that the modifications persist long enough to contribute to long-term memory storage, and that key variables governing the sign of synaptic plasticity are the amount of NMDA receptor activation and the recent history of cortical activity.

Precision spectral manipulation of optical pulses using a coherent photon echo memory.

PubMed

Buchler, B C; Hosseini, M; Hétet, G; Sparkes, B M; Lam, P K

2010-04-01

Photon echo schemes are excellent candidates for high efficiency coherent optical memory. They are capable of high-bandwidth multipulse storage, pulse resequencing and have been shown theoretically to be compatible with quantum information applications. One particular photon echo scheme is the gradient echo memory (GEM). In this system, an atomic frequency gradient is induced in the direction of light propagation leading to a Fourier decomposition of the optical spectrum along the length of the storage medium. This Fourier encoding allows precision spectral manipulation of the stored light. In this Letter, we show frequency shifting, spectral compression, spectral splitting, and fine dispersion control of optical pulses using GEM.

Optical memory development. Volume 2: Gain-assisted holographic storage media

NASA Technical Reports Server (NTRS)

Gange, R. A.; Mezrich, R. S.

1972-01-01

Thin deformable films were investigated for use as the storage medium in a holographic optical memory. The research was directed toward solving the problems of material fatigue, selective heat addressing, electrical charging of the film surface and charge patterning by light. A number of solutions to these problems were found but the main conclusion to be drawn from the work is that deformable media which employ heat in the recording process are not satisfactory for use in a high-speed random-access read/write holographic memory. They are, however, a viable approach in applications where either high speed or random-access is not required.

PCM-Based Durable Write Cache for Fast Disk I/O

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Zhuo; Wang, Bin; Carpenter, Patrick

2012-01-01

Flash based solid-state devices (FSSDs) have been adopted within the memory hierarchy to improve the performance of hard disk drive (HDD) based storage system. However, with the fast development of storage-class memories, new storage technologies with better performance and higher write endurance than FSSDs are emerging, e.g., phase-change memory (PCM). Understanding how to leverage these state-of-the-art storage technologies for modern computing systems is important to solve challenging data intensive computing problems. In this paper, we propose to leverage PCM for a hybrid PCM-HDD storage architecture. We identify the limitations of traditional LRU caching algorithms for PCM-based caches, and develop amore » novel hash-based write caching scheme called HALO to improve random write performance of hard disks. To address the limited durability of PCM devices and solve the degraded spatial locality in traditional wear-leveling techniques, we further propose novel PCM management algorithms that provide effective wear-leveling while maximizing access parallelism. We have evaluated this PCM-based hybrid storage architecture using applications with a diverse set of I/O access patterns. Our experimental results demonstrate that the HALO caching scheme leads to an average reduction of 36.8% in execution time compared to the LRU caching scheme, and that the SFC wear leveling extends the lifetime of PCM by a factor of 21.6.« less

Scalable quantum memory in the ultrastrong coupling regime.

PubMed

Kyaw, T H; Felicetti, S; Romero, G; Solano, E; Kwek, L-C

2015-03-02

Circuit quantum electrodynamics, consisting of superconducting artificial atoms coupled to on-chip resonators, represents a prime candidate to implement the scalable quantum computing architecture because of the presence of good tunability and controllability. Furthermore, recent advances have pushed the technology towards the ultrastrong coupling regime of light-matter interaction, where the qubit-resonator coupling strength reaches a considerable fraction of the resonator frequency. Here, we propose a qubit-resonator system operating in that regime, as a quantum memory device and study the storage and retrieval of quantum information in and from the Z2 parity-protected quantum memory, within experimentally feasible schemes. We are also convinced that our proposal might pave a way to realize a scalable quantum random-access memory due to its fast storage and readout performances.

Scalable quantum memory in the ultrastrong coupling regime

PubMed Central

Kyaw, T. H.; Felicetti, S.; Romero, G.; Solano, E.; Kwek, L.-C.

2015-01-01

Circuit quantum electrodynamics, consisting of superconducting artificial atoms coupled to on-chip resonators, represents a prime candidate to implement the scalable quantum computing architecture because of the presence of good tunability and controllability. Furthermore, recent advances have pushed the technology towards the ultrastrong coupling regime of light-matter interaction, where the qubit-resonator coupling strength reaches a considerable fraction of the resonator frequency. Here, we propose a qubit-resonator system operating in that regime, as a quantum memory device and study the storage and retrieval of quantum information in and from the Z2 parity-protected quantum memory, within experimentally feasible schemes. We are also convinced that our proposal might pave a way to realize a scalable quantum random-access memory due to its fast storage and readout performances. PMID:25727251

Cyclic Nucleotide-Gated Channels, Calmodulin, Adenylyl Cyclase, and Calcium/Calmodulin-Dependent Protein Kinase II Are Required for Late, but Not Early, Long-Term Memory Formation in the Honeybee

ERIC Educational Resources Information Center

Matsumoto, Yukihisa; Sandoz, Jean-Christophe; Devaud, Jean-Marc; Lormant, Flore; Mizunami, Makoto; Giurfa, Martin

2014-01-01

Memory is a dynamic process that allows encoding, storage, and retrieval of information acquired through individual experience. In the honeybee "Apis mellifera," olfactory conditioning of the proboscis extension response (PER) has shown that besides short-term memory (STM) and mid-term memory (MTM), two phases of long-term memory (LTM)…

Allograft dendritic cell p40 homodimers activate donor-reactive memory CD8+ T cells

PubMed Central

Tsuda, Hidetoshi; Su, Charles A.; Tanaka, Toshiaki; Ayasoufi, Katayoun; Min, Booki; Valujskikh, Anna; Fairchild, Robert L.

2018-01-01

Recipient endogenous memory T cells with donor reactivity pose an important barrier to successful transplantation and costimulatory blockade–induced graft tolerance. Longer ischemic storage times prior to organ transplantation increase early posttransplant inflammation and negatively impact early graft function and long-term graft outcome. Little is known about the mechanisms enhancing endogenous memory T cell activation to mediate tissue injury within the increased inflammatory environment of allografts subjected to prolonged cold ischemic storage (CIS). Endogenous memory CD4+ and CD8+ T cell activation is markedly increased within complete MHC-mismatched cardiac allografts subjected to prolonged versus minimal CIS, and the memory CD8+ T cells directly mediate CTLA-4Ig–resistant allograft rejection. Memory CD8+ T cell activation within allografts subjected to prolonged CIS requires memory CD4+ T cell stimulation of graft DCs to produce p40 homodimers, but not IL-12 p40/p35 heterodimers. Targeting p40 abrogates memory CD8+ T cell proliferation within the allografts and their ability to mediate CTLA-4Ig–resistant allograft rejection. These findings indicate a critical role for memory CD4+ T cell–graft DC interactions to increase the intensity of endogenous memory CD8+ T cell activation needed to mediate rejection of higher-risk allografts subjected to increased CIS. PMID:29467328

An interactive display system for large-scale 3D models

NASA Astrophysics Data System (ADS)

Liu, Zijian; Sun, Kun; Tao, Wenbing; Liu, Liman

2018-04-01

With the improvement of 3D reconstruction theory and the rapid development of computer hardware technology, the reconstructed 3D models are enlarging in scale and increasing in complexity. Models with tens of thousands of 3D points or triangular meshes are common in practical applications. Due to storage and computing power limitation, it is difficult to achieve real-time display and interaction with large scale 3D models for some common 3D display software, such as MeshLab. In this paper, we propose a display system for large-scale 3D scene models. We construct the LOD (Levels of Detail) model of the reconstructed 3D scene in advance, and then use an out-of-core view-dependent multi-resolution rendering scheme to realize the real-time display of the large-scale 3D model. With the proposed method, our display system is able to render in real time while roaming in the reconstructed scene and 3D camera poses can also be displayed. Furthermore, the memory consumption can be significantly decreased via internal and external memory exchange mechanism, so that it is possible to display a large scale reconstructed scene with over millions of 3D points or triangular meshes in a regular PC with only 4GB RAM.

Memory in autistic spectrum disorder.

PubMed

Boucher, Jill; Mayes, Andrew; Bigham, Sally

2012-05-01

Behavioral evidence concerning memory in forms of high-functioning autism (HFA) and in moderately low-functioning autism (M-LFA) is reviewed and compared. Findings on M-LFA are sparse. However, it is provisionally concluded that memory profiles in HFA and M-LFA (relative to ability-matched controls) are similar but that declarative memory impairments are more extensive in M-LFA than in HFA. Specifically, both groups have diminished memory for emotion- or person-related stimuli. Regarding memory for nonsocial stimuli, both groups probably have mental-age-appropriate nondeclarative memory, and within declarative memory, both groups have mental-age-appropriate immediate free recall of within-span or supraspan lists of unrelated items, as well as cued recall and paired associate learning. By contrast, recognition is largely unimpaired in HFA but moderately impaired in M-LFA, and free recall of meaningful or structured stimuli is moderately impaired in HFA but more severely impaired in M-LFA. Theoretical explanations of data on declarative memory in HFA identify problems in the integrative processing, or the consolidation and storage, of complex stimuli or a specific problem of recollection. Proposed neural substrates include the following: disconnectivity of primary sensory and association areas; dysfunctions of medial prefrontal cortex, hippocampus, or posterior parietal lobe; or combinations of these associated with neural disconnectivity. Hypothetically, perirhinal dysfunction might explain the more extensive declarative memory impairments in M-LFA. Foreseeable consequences of uneven memory abilities in HFA and M-LFA are outlined, including possible effects on language and learning in M-LFA. Finally, priorities for future research are identified, highlighting the urgent need for research on memory in lower functioning individuals. 2012 APA, all rights reserved

Real-time associative memory with photorefractive crystal KNSBN and liquid-crystal optical switches

NASA Astrophysics Data System (ADS)

Xu, Haiying; Yuan, Yang Y.; Yu, Youlong; Xu, Kebin; Xu, Yuhuan; Zhu, De-Rui

1990-05-01

We present a real-time holographic associative memory implemented with photorefractive KNSBN : Co crystal as memory element and liquid crystal electrooptical switches as reflective thresholding device. The experimental results show that the system has real-time multiple-image storage and recall function.

Infants Hierarchically Organize Memory Representations

ERIC Educational Resources Information Center

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…

Time, Language, and Autobiographical Memory

ERIC Educational Resources Information Center

Burt, Christopher D. B.

2008-01-01

Life themes, general events, and event-specific episodes, together with autobiographical knowledge, form autobiographical memory. Each of these memory structures is described, and research that has investigated the storage and retrieval of temporal information for life events, such as place in time, duration, and order, is examined. The general…

Sparse, decorrelated odor coding in the mushroom body enhances learned odor discrimination.

PubMed

Lin, Andrew C; Bygrave, Alexei M; de Calignon, Alix; Lee, Tzumin; Miesenböck, Gero

2014-04-01

Sparse coding may be a general strategy of neural systems for augmenting memory capacity. In Drosophila melanogaster, sparse odor coding by the Kenyon cells of the mushroom body is thought to generate a large number of precisely addressable locations for the storage of odor-specific memories. However, it remains untested how sparse coding relates to behavioral performance. Here we demonstrate that sparseness is controlled by a negative feedback circuit between Kenyon cells and the GABAergic anterior paired lateral (APL) neuron. Systematic activation and blockade of each leg of this feedback circuit showed that Kenyon cells activated APL and APL inhibited Kenyon cells. Disrupting the Kenyon cell-APL feedback loop decreased the sparseness of Kenyon cell odor responses, increased inter-odor correlations and prevented flies from learning to discriminate similar, but not dissimilar, odors. These results suggest that feedback inhibition suppresses Kenyon cell activity to maintain sparse, decorrelated odor coding and thus the odor specificity of memories.

Youthful Brains in Older Adults: Preserved Neuroanatomy in the Default Mode and Salience Networks Contributes to Youthful Memory in Superaging.

PubMed

Sun, Felicia W; Stepanovic, Michael R; Andreano, Joseph; Barrett, Lisa Feldman; Touroutoglou, Alexandra; Dickerson, Bradford C

2016-09-14

Decline in cognitive skills, especially in memory, is often viewed as part of "normal" aging. Yet some individuals "age better" than others. Building on prior research showing that cortical thickness in one brain region, the anterior midcingulate cortex, is preserved in older adults with memory performance abilities equal to or better than those of people 20-30 years younger (i.e., "superagers"), we examined the structural integrity of two large-scale intrinsic brain networks in superaging: the default mode network, typically engaged during memory encoding and retrieval tasks, and the salience network, typically engaged during attention, motivation, and executive function tasks. We predicted that superagers would have preserved cortical thickness in critical nodes in these networks. We defined superagers (60-80 years old) based on their performance compared to young adults (18-32 years old) on the California Verbal Learning Test Long Delay Free Recall test. We found regions within the networks of interest where the cerebral cortex of superagers was thicker than that of typical older adults, and where superagers were anatomically indistinguishable from young adults; hippocampal volume was also preserved in superagers. Within the full group of older adults, thickness of a number of regions, including the anterior temporal cortex, rostral medial prefrontal cortex, and anterior midcingulate cortex, correlated with memory performance, as did the volume of the hippocampus. These results indicate older adults with youthful memory abilities have youthful brain regions in key paralimbic and limbic nodes of the default mode and salience networks that support attentional, executive, and mnemonic processes subserving memory function. Memory performance typically declines with age, as does cortical structural integrity, yet some older adults maintain youthful memory. We tested the hypothesis that superagers (older individuals with youthful memory performance) would exhibit preserved neuroanatomy in key brain networks subserving memory. We found that superagers not only perform similarly to young adults on memory testing, they also do not show the typical patterns of brain atrophy in certain regions. These regions are contained largely within two major intrinsic brain networks: the default mode network, implicated in memory encoding, storage, and retrieval, and the salience network, associated with attention and executive processes involved in encoding and retrieval. Preserved neuroanatomical integrity in these networks is associated with better memory performance among older adults. Copyright © 2016 Sun, Stepanovic et al.

Deformation and Failure Mechanisms of Shape Memory Alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Daly, Samantha Hayes

2015-04-15

The goal of this research was to understand the fundamental mechanics that drive the deformation and failure of shape memory alloys (SMAs). SMAs are difficult materials to characterize because of the complex phase transformations that give rise to their unique properties, including shape memory and superelasticity. These phase transformations occur across multiple length scales (one example being the martensite-austenite twinning that underlies macroscopic strain localization) and result in a large hysteresis. In order to optimize the use of this hysteretic behavior in energy storage and damping applications, we must first have a quantitative understanding of this transformation behavior. Prior resultsmore » on shape memory alloys have been largely qualitative (i.e., mapping phase transformations through cracked oxide coatings or surface morphology). The PI developed and utilized new approaches to provide a quantitative, full-field characterization of phase transformation, conducting a comprehensive suite of experiments across multiple length scales and tying these results to theoretical and computational analysis. The research funded by this award utilized new combinations of scanning electron microscopy, diffraction, digital image correlation, and custom testing equipment and procedures to study phase transformation processes at a wide range of length scales, with a focus at small length scales with spatial resolution on the order of 1 nanometer. These experiments probe the basic connections between length scales during phase transformation. In addition to the insights gained on the fundamental mechanisms driving transformations in shape memory alloys, the unique experimental methodologies developed under this award are applicable to a wide range of solid-to-solid phase transformations and other strain localization mechanisms.« less

Redundant disk arrays: Reliable, parallel secondary storage. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Gibson, Garth Alan

1990-01-01

During the past decade, advances in processor and memory technology have given rise to increases in computational performance that far outstrip increases in the performance of secondary storage technology. Coupled with emerging small-disk technology, disk arrays provide the cost, volume, and capacity of current disk subsystems, by leveraging parallelism, many times their performance. Unfortunately, arrays of small disks may have much higher failure rates than the single large disks they replace. Redundant arrays of inexpensive disks (RAID) use simple redundancy schemes to provide high data reliability. The data encoding, performance, and reliability of redundant disk arrays are investigated. Organizing redundant data into a disk array is treated as a coding problem. Among alternatives examined, codes as simple as parity are shown to effectively correct single, self-identifying disk failures.

An energy efficient and high speed architecture for convolution computing based on binary resistive random access memory

NASA Astrophysics Data System (ADS)

Liu, Chen; Han, Runze; Zhou, Zheng; Huang, Peng; Liu, Lifeng; Liu, Xiaoyan; Kang, Jinfeng

2018-04-01

In this work we present a novel convolution computing architecture based on metal oxide resistive random access memory (RRAM) to process the image data stored in the RRAM arrays. The proposed image storage architecture shows performances of better speed-device consumption efficiency compared with the previous kernel storage architecture. Further we improve the architecture for a high accuracy and low power computing by utilizing the binary storage and the series resistor. For a 28 × 28 image and 10 kernels with a size of 3 × 3, compared with the previous kernel storage approach, the newly proposed architecture shows excellent performances including: 1) almost 100% accuracy within 20% LRS variation and 90% HRS variation; 2) more than 67 times speed boost; 3) 71.4% energy saving.

At the Intersection of Attention and Memory: The Mechanistic Role of the Posterior Parietal Lobe in Working Memory

ERIC Educational Resources Information Center

Berryhill, Marian E.; Chein, Jason; Olson, Ingrid R.

2011-01-01

Portions of the posterior parietal cortex (PPC) play a role in working memory (WM) yet the precise mechanistic function of this region remains poorly understood. The "pure storage" hypothesis proposes that this region functions as a short-lived modality-specific memory store. Alternatively, the "internal attention" hypothesis proposes that the PPC…

Decoding complex flow-field patterns in visual working memory.

PubMed

Christophel, Thomas B; Haynes, John-Dylan

2014-05-01

There has been a long history of research on visual working memory. Whereas early studies have focused on the role of lateral prefrontal cortex in the storage of sensory information, this has been challenged by research in humans that has directly assessed the encoding of perceptual contents, pointing towards a role of visual and parietal regions during storage. In a previous study we used pattern classification to investigate the storage of complex visual color patterns across delay periods. This revealed coding of such contents in early visual and parietal brain regions. Here we aim to investigate whether the involvement of visual and parietal cortex is also observable for other types of complex, visuo-spatial pattern stimuli. Specifically, we used a combination of fMRI and multivariate classification to investigate the retention of complex flow-field stimuli defined by the spatial patterning of motion trajectories of random dots. Subjects were trained to memorize the precise spatial layout of these stimuli and to retain this information during an extended delay. We used a multivariate decoding approach to identify brain regions where spatial patterns of activity encoded the memorized stimuli. Content-specific memory signals were observable in motion sensitive visual area MT+ and in posterior parietal cortex that might encode spatial information in a modality independent manner. Interestingly, we also found information about the memorized visual stimulus in somatosensory cortex, suggesting a potential crossmodal contribution to memory. Our findings thus indicate that working memory storage of visual percepts might be distributed across unimodal, multimodal and even crossmodal brain regions. Copyright © 2014 Elsevier Inc. All rights reserved.

Some Considerations Necessary for a Viable Theory of Human Memory.

ERIC Educational Resources Information Center

Sietsema, Douglas J.

Empirical research is reviewed in the area of cognitive psychology pertaining to models of human memory. Research evidence and theoretical considerations are combined to develop guidelines for future theory development related to the human memory. The following theoretical constructs and variables are discussed: (1) storage versus process…

The Cognitive and Neural Correlates of Tactile Memory

ERIC Educational Resources Information Center

Gallace, Alberto; Spence, Charles

2009-01-01

Tactile memory systems are involved in the storage and retrieval of information about stimuli that impinge on the body surface and objects that people explore haptically. Here, the authors review the behavioral, neuropsychological, neurophysiological, and neuroimaging research on tactile memory. This body of research reveals that tactile memory…

Visuospatial Immediate Memory in Specific Language Impairment

ERIC Educational Resources Information Center

Archibald, Lisa M. D.; Gathercole, Susan E.

2006-01-01

Purpose: Investigations of the cognitive processes underlying specific language impairment (SLI) have implicated deficits in verbal short-term and working memory and in particular the storage and processing of phonological information. This study investigated short-term and working memory for visuospatial material for a group of children with SLI,…

Effects of Serial Rehearsal Training on Memory Search

ERIC Educational Resources Information Center

McCauley, Charley; And Others

1976-01-01

Half the subjects were trained to use a serial rehearsal strategy during target set storage and half were given no strategy training. The results indicate that the rate of memory search is IQ-related, and that serial rehearsal training facilitates memory search when rehearsal is covert. (Author/BW)

Reexamining the Relationship between Working Memory and Comprehension: The Role of Available Long-Term Memory

ERIC Educational Resources Information Center

Was, Christopher A.; Woltz, Dan J.

2007-01-01

Two individual differences studies tested relationships between listening comprehension and two conceptualizations of working memory (WM) capacity. Recently, some theorists have stressed that the empirically indicated limits of rehearsal-based WM storage components are inconsistent with the amounts of information needed to accomplish complex…

Experimental Optoelectronic Associative Memory

NASA Technical Reports Server (NTRS)

Chao, Tien-Hsin

1992-01-01

Optoelectronic associative memory responds to input image by displaying one of M remembered images. Which image to display determined by optoelectronic analog computation of resemblance between input image and each remembered image. Does not rely on precomputation and storage of outer-product synapse matrix. Size of memory needed to store and process images reduced.

An Approach toward the Development of a Functional Encoding Model of Short Term Memory during Reading.

ERIC Educational Resources Information Center

Herndon, Mary Anne

1978-01-01

In a model of the functioning of short term memory, the encoding of information for subsequent storage in long term memory is simulated. In the encoding process, semantically equivalent paragraphs are detected for recombination into a macro information unit. (HOD)

Fabrication and characterization of shape memory polymers at small-scales

NASA Astrophysics Data System (ADS)

Wornyo, Edem

The objective of this research is to thoroughly investigate the shape memory effect in polymers, characterize, and optimize these polymers for applications in information storage systems. Previous research effort in this field concentrated on shape memory metals for biomedical applications such as stents. Minimal work has been done on shape memory polymers; and the available work on shape memory polymers has not characterized the behaviors of this category of polymers fully. Copolymer shape memory materials based on diethylene glycol dimethacrylate (DEGDMA) crosslinker, and tert butyl acrylate (tBA) monomer are designed. The design encompasses a careful control of the backbone chemistry of the materials. Characterization methods such as dynamic mechanical analysis (DMA), differential scanning calorimetry (DSC); and novel nanoscale techniques such as atomic force microscopy (AFM), and nanoindentation are applied to this system of materials. Designed experiments are conducted on the materials to optimize spin coating conditions for thin films. Furthermore, the recovery, a key for the use of these polymeric materials for information storage, is examined in detail with respect to temperature. In sum, the overarching objectives of the proposed research are to: (i) Design shape memory polymers based on polyethylene glycol dimethacrylate (PEGDMA) and diethylene glycol dimethacrylate (DEGDMA) crosslinkers, 2-hydroxyethyl methacrylate (HEMA) and tert-butyl acrylate monomer (tBA). (ii) Utilize dynamic mechanical analysis (DMA) to comprehend the thermomechanical properties of shape memory polymers based on DEGDMA and tBA. (iii) Utilize nanoindentation and atomic force microscopy (AFM) to understand the nanoscale behavior of these SMPs, and explore the strain storage and recovery of the polymers from a deformed state. (iv) Study spin coating conditions on thin film quality with designed experiments. (iv) Apply neural networks and genetic algorithms to optimize these systems.

Cortical rewiring and information storage

NASA Astrophysics Data System (ADS)

Chklovskii, D. B.; Mel, B. W.; Svoboda, K.

2004-10-01

Current thinking about long-term memory in the cortex is focused on changes in the strengths of connections between neurons. But ongoing structural plasticity in the adult brain, including synapse formation/elimination and remodelling of axons and dendrites, suggests that memory could also depend on learning-induced changes in the cortical `wiring diagram'. Given that the cortex is sparsely connected, wiring plasticity could provide a substantial boost in storage capacity, although at a cost of more elaborate biological machinery and slower learning.

Radiation Effects on Advanced Flash Memories

NASA Technical Reports Server (NTRS)

Nguyen, D. N.; Guertin, S.; Swift, G. M.; Johnston, A. H.

1998-01-01

Flash memories have evolved very rapidly in recent ears. New design techniques such as multilevel storage have been proposed to increase storage density, and are now available commercially. Threshold voltage distributions for single- and three-level technologies are compared. In order to implement this technology special circuitry must be added to allow the amount of charge stored in the floating gate to be controlled within narrow limits during the writing and also to detect the different amounts of charge during reading.

Centrifugal Spinning and Its Energy Storage Applications

NASA Astrophysics Data System (ADS)

Yao, Lu

Lithium-ion batteries (LIBs) and supercapacitors are important electrochemical energy storage systems. LIBs have high specific energy density, long cycle life, good thermal stability, low self-discharge, and no memory effect. However, the low abundance of Li in the Earth's crust and the rising cost of LIBs urge the attempts to develop alternative energy storage systems. Recently, sodium-ion batteries (SIBs) have become an attractive alternative to LIBs due to the high abundance and low cost of Na. Although the specific capacity and energy density of SIBs are not as high as LIBs, SIBs can still be promising power sources for certain applications such as large-scale, stationary grids. Supercapacitors are another important class of energy storage devices. Electric double-layer capacitors (EDLCs) are one important type of supercapacitors and they exhibit high power density, long cycle life, excellent rate capability and environmental friendliness. The potential applications of supercapacitors include memory protection in electronic circuitry, consumer portable electronic devices, and electrical hybrid vehicles. The electrochemical performance of SIBs and EDLCs is largely dependent on the electrode materials. Therefore, development of superior electrodes is the key to achieve highperformance alternative energy storage systems. Recently, one-dimensional nano-/micro-fiber based electrodes have become promising candidates in energy storage because they possess a variety of desirable properties including large specific surface area, well-guided ionic/electronic transport, and good electrode-electrolyte contact, which contribute to enhanced electrochemical performance. Currently, most nano-/micro-fiber based electrodes are prepared via electrospinning method. However, the low production rate of this approach hinders its practical application in the production of fibrous electrodes. Thus, it is significantly important to employ a rapid, low-cost and scalable nano-/micro-fiber production method to substitute electrospinning in industrial production. Recently, centrifugal spinning has gained researchers' attention. The centrifugal spinning method avoids the use of high voltage supply and can work with concentrated solutions, and most importantly, it can increase the production rate of nano-/micro-fibers to at least two orders or magnitude higher than that of electrospinning. This novel fiber fabrication approach is mostly used in tissue engineering field, and it can be potentially applied in preparing electrodes for SIBs and EDLCs. In the present work, we firstly study the influence of solution intrinsic properties and operational parameters using polyacrylonitrile as an example, and establish the processing-structure relationships for this spinning technique. We then use this novel spinning method to prepare porous carbon nanofibers (PCNFs), SnO2 microfibers and lithium-substituted sodium layered transition metal oxide fibers and use them as electrodes for EDLCs and SIBs. The as-prepared PCNFs, SnO2 microfibers and lithiumsubstituted sodium layered transition metal oxide fibers exhibit good electrochemical performance. It is therefore demonstrated that centrifugal spinning can be a promising nano- /micro-fiber preparation approach for mass production of electrode materials used in energy storage applications.

Optical memory system technology. Citations from the International Aerospace Abstracts data base

NASA Technical Reports Server (NTRS)

Zollars, G. F.

1980-01-01

Approximately 213 citations from the international literature which concern the development of the optical data storage system technology are presented. Topics covered include holographic computer storage devices, crystal, magneto, and electro-optics, imaging techniques, in addition to optical data processing and storage.

The contribution of acetylcholine and dopamine to subprocesses of visual working memory--what patients with amnestic mild cognitive impairment and Parkinson׳s disease can tell us.

PubMed

Blatt, Joana; Vellage, Anne; Baier, Bernhard; Müller, Notger G

2014-08-01

Attentional selection, i.e. filtering out of irrelevant sensory input and information storage are two crucial components of working memory (WM). It has been proposed that the two processes are mediated by different neurotransmitters, namely acetylcholine for attentional selection and dopamine for memory storage. However, this hypothesis has been challenged by others, who for example linked a lack in dopamine levels in the brain to filtering deficits. Here we tested the above mentioned hypothesis in two patient cohorts which either served as a proxy for a cholinergic or a dopaminergic deficit. The first group comprised 18 patients with amnestic mild cognitive impairment (aMCI), the second 22 patients with Parkinson׳s disease (PD). The two groups did not differ regarding their overall cognitive abilities. Both patient groups as well as a control group without neurological deficits (n=25) performed a visuo-spatial working memory task in which both the necessity to filter out irrelevant information and memory load, i.e. the number of items to be held in memory, were manipulated. In accordance with the primary hypothesis, aMCI patients displayed problems with filtering, i.e., were especially impaired when the task required ignoring distracting stimuli. PD patients on the other hand showed difficulties when memory load was increased suggesting that they mainly suffered from a storage deficit. In sum, this study underlines how the investigation of neurologic patients with a presumed neurotransmitter deficit can aid to clarify these neurotransmitters׳ contribution to specific cognitive functions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Contributions of volumetrics of the hippocampus and thalamus to verbal memory in temporal lobe epilepsy patients.

PubMed

Stewart, Christopher C; Griffith, H Randall; Okonkwo, Ozioma C; Martin, Roy C; Knowlton, Robert K; Richardson, Elizabeth J; Hermann, Bruce P; Seidenberg, Michael

2009-02-01

Recent theories have posited that the hippocampus and thalamus serve distinct, yet related, roles in episodic memory. Whereas the hippocampus has been implicated in long-term memory encoding and storage, the thalamus, as a whole, has been implicated in the selection of items for subsequent encoding and the use of retrieval strategies. However, dissociating the memory impairment that occurs following thalamic injury as distinguished from that following hippocampal injury has proven difficult. This study examined relationships between MRI volumetric measures of the hippocampus and thalamus and their contributions to prose and rote verbal memory functioning in 18 patients with intractable temporal lobe epilepsy (TLE). Results revealed that bilateral hippocampal and thalamic volume independently predicted delayed prose verbal memory functioning. However, bilateral hippocampal, but not thalamic, volume predicted delayed rote verbal memory functioning. Follow-up analyses indicated that bilateral thalamic volume independently predicted immediate prose, but not immediate rote, verbal recall, whereas bilateral hippocampal volume was not associated with any of these immediate memory measures. These findings underscore the cognitive significance of thalamic atrophy in chronic TLE, demonstrating that hippocampal and thalamic volume make quantitatively, and perhaps qualitatively, distinct contributions to episodic memory functioning in TLE patients. They are also consistent with theories proposing that the hippocampus supports long-term memory encoding and storage, whereas the thalamus is implicated in the executive aspects of episodic memory.

CLOCS (Computer with Low Context-Switching Time) Architecture Reference Documents

DTIC Science & Technology

1988-05-06

Peculiarities The only state inside the central processing unit(CPU) is a program status word. All data operations are memory to memory. One result of this... to the challenge "if I whore to design RISC, this is how I would do it." The architecture was designed by Mark Davis and Bill Gallmeister. 1.2...are memory to memory. Any special devices added should be memory mapped. The program counter is even memory mapped. 1.3.1 Working storage There is no

Distributed and Dynamic Storage of Working Memory Stimulus Information in Extrastriate Cortex

PubMed Central

Sreenivasan, Kartik K.; Vytlacil, Jason; D'Esposito, Mark

2015-01-01

The predominant neurobiological model of working memory (WM) posits that stimulus information is stored via stable elevated activity within highly selective neurons. Based on this model, which we refer to as the canonical model, the storage of stimulus information is largely associated with lateral prefrontal cortex (lPFC). A growing number of studies describe results that cannot be fully explained by the canonical model, suggesting that it is in need of revision. In the present study, we directly test key elements of the canonical model. We analyzed functional MRI data collected as participants performed a task requiring WM for faces and scenes. Multivariate decoding procedures identified patterns of activity containing information about the items maintained in WM (faces, scenes, or both). While information about WM items was identified in extrastriate visual cortex (EC) and lPFC, only EC exhibited a pattern of results consistent with a sensory representation. Information in both regions persisted even in the absence of elevated activity, suggesting that elevated population activity may not represent the storage of information in WM. Additionally, we observed that WM information was distributed across EC neural populations that exhibited a broad range of selectivity for the WM items rather than restricted to highly selective EC populations. Finally, we determined that activity patterns coding for WM information were not stable, but instead varied over the course of a trial, indicating that the neural code for WM information is dynamic rather than static. Together, these findings challenge the canonical model of WM. PMID:24392897

A new pattern associative memory model for image recognition based on Hebb rules and dot product

NASA Astrophysics Data System (ADS)

Gao, Mingyue; Deng, Limiao; Wang, Yanjiang

2018-04-01

A great number of associative memory models have been proposed to realize information storage and retrieval inspired by human brain in the last few years. However, there is still much room for improvement for those models. In this paper, we extend a binary pattern associative memory model to accomplish real-world image recognition. The learning process is based on the fundamental Hebb rules and the retrieval is implemented by a normalized dot product operation. Our proposed model can not only fulfill rapid memory storage and retrieval for visual information but also have the ability on incremental learning without destroying the previous learned information. Experimental results demonstrate that our model outperforms the existing Self-Organizing Incremental Neural Network (SOINN) and Back Propagation Neuron Network (BPNN) on recognition accuracy and time efficiency.

A new approach for two-terminal electronic memory devices - Storing information on silicon nanowires

NASA Astrophysics Data System (ADS)

Saranti, Konstantina; Alotaibi, Sultan; Paul, Shashi

2016-06-01

The work described in this paper focuses on the utilisation of silicon nanowires as the information storage element in flash-type memory devices. Silicon nanostructures have attracted attention due to interesting electrical and optical properties, and their potential integration into electronic devices. A detailed investigation of the suitability of silicon nanowires as the charge storage medium in two-terminal non-volatile memory devices are presented in this report. The deposition of the silicon nanostructures was carried out at low temperatures (less than 400 °C) using a previously developed a novel method within our research group. Two-terminal non-volatile (2TNV) memory devices and metal-insulator-semiconductor (MIS) structures containing the silicon nanowires were fabricated and an in-depth study of their characteristics was carried out using current-voltage and capacitance techniques.

Single-photon-level quantum image memory based on cold atomic ensembles

PubMed Central

Ding, Dong-Sheng; Zhou, Zhi-Yuan; Shi, Bao-Sen; Guo, Guang-Can

2013-01-01

A quantum memory is a key component for quantum networks, which will enable the distribution of quantum information. Its successful development requires storage of single-photon light. Encoding photons with spatial shape through higher-dimensional states significantly increases their information-carrying capability and network capacity. However, constructing such quantum memories is challenging. Here we report the first experimental realization of a true single-photon-carrying orbital angular momentum stored via electromagnetically induced transparency in a cold atomic ensemble. Our experiments show that the non-classical pair correlation between trigger photon and retrieved photon is retained, and the spatial structure of input and retrieved photons exhibits strong similarity. More importantly, we demonstrate that single-photon coherence is preserved during storage. The ability to store spatial structure at the single-photon level opens the possibility for high-dimensional quantum memories. PMID:24084711

If It Is Stored in My Memory I Will Surely Retrieve It: Anatomy of a Metacognitive Belief

ERIC Educational Resources Information Center

Kornell, Nate

2015-01-01

Retrieval failures--moments when a memory will not come to mind--are a universal human experience. Yet many laypeople believe human memory is a reliable storage system in which a stored memory should be accessible. I predicted that people would see retrieval failures as aberrations and predict that fewer retrieval failures would happen in the…

Modelling the effects of Prairie wetlands on streamflow

NASA Astrophysics Data System (ADS)

Shook, K.; Pomeroy, J. W.

2015-12-01

Recent research has demonstrated that the contributing areas of Prairie streams dominated by depressional (wetland) storage demonstrate hysteresis with respect to catchment water storage. As such contributing fractions can vary over time from a very small percentage of catchment area to the entire catchment during floods. However, catchments display complex memories of past storage states and their contributing fractions cannot be modelled accurately by any single-valued function. The Cold Regions Hydrological Modelling platform, CRHM, which is capable of modelling all of the hydrological processes of cold regions using a hydrological response unit discretization of the catchment, was used to further investigate dynamical contributing area response to hydrological processes. Contributing fraction in CRHM is also controlled by the episodic nature of runoff generation in this cold, sub-humid environment where runoff is dominated by snowmelt over frozen soils, snowdrifts define the contributing fraction in late spring, unfrozen soils have high water holding capacity and baseflow from sub-surface flow does not exist. CRHM was improved by adding a conceptual model of individual Prairie depression fill and spill runoff generation that displays hysteresis in the storage - contributing fraction relationship and memory of storage state. The contributing area estimated by CRHM shows strong sensitivity to hydrological inputs, storage and the threshold runoff rate chosen. The response of the contributing area to inputs from various runoff generating processes from snowmelt to rain-on-snow to rainfall with differing degrees of spatial variation was investigated as was the importance of the memory of storage states on streamflow generation. The importance of selecting hydrologically and ecologically meaningful runoff thresholds in estimating contributing area is emphasized.

Efficient checkpointing schemes for depletion perturbation solutions on memory-limited architectures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stripling, H. F.; Adams, M. L.; Hawkins, W. D.

2013-07-01

We describe a methodology for decreasing the memory footprint and machine I/O load associated with the need to access a forward solution during an adjoint solve. Specifically, we are interested in the depletion perturbation equations, where terms in the adjoint Bateman and transport equations depend on the forward flux solution. Checkpointing is the procedure of storing snapshots of the forward solution to disk and using these snapshots to recompute the parts of the forward solution that are necessary for the adjoint solve. For large problems, however, the storage cost of just a few copies of an angular flux vector canmore » exceed the available RAM on the host machine. We propose a methodology that does not checkpoint the angular flux vector; instead, we write and store converged source moments, which are typically of a much lower dimension than the angular flux solution. This reduces the memory footprint and I/O load of the problem, but requires that we perform single sweeps to reconstruct flux vectors on demand. We argue that this trade-off is exactly the kind of algorithm that will scale on advanced, memory-limited architectures. We analyze the cost, in terms of FLOPS and memory footprint, of five checkpointing schemes. We also provide computational results that support the analysis and show that the memory-for-work trade off does improve time to solution. (authors)« less

Improved charge trapping properties by embedded graphene oxide quantum-dots for flash memory application

NASA Astrophysics Data System (ADS)

Jia, Xinlei; Yan, Xiaobing; Wang, Hong; Yang, Tao; Zhou, Zhenyu; Zhao, Jianhui

2018-06-01

In this work, we have investigated two kinds of charge trapping memory devices with Pd/Al2O3/ZnO/SiO2/p-Si and Pd/Al2O3/ZnO/graphene oxide quantum-dots (GOQDs)/ZnO/SiO2/p-Si structure. Compared with the single ZnO sample, the memory window of the ZnO-GOQDs-ZnO sample reaches a larger value (more than doubled) of 2.7 V under the sweeping gate voltage ± 7 V, indicating a better charge storage capability and the significant charge trapping effects by embedding the GOQDs trapping layer. The ZnO-GOQDs-ZnO devices have better date retention properties with the high and low capacitances loss of ˜ 1.1 and ˜ 6.9%, respectively, as well as planar density of the trapped charges of 1.48 × 1012 cm- 2. It is proposed that the GOQDs play an important role in the outstanding memory characteristics due to the deep quantum potential wells and the discrete distribution of the GOQDs. The long date retention time might have resulted from the high potential barrier which suppressed both the back tunneling and the leakage current. Intercalating GOQDs in the memory device is a promising method to realize large memory window, low-power consumption and excellent retention properties.

Pentacene-based metal-insulator-semiconductor memory structures utilizing single walled carbon nanotubes as a nanofloating gate

NASA Astrophysics Data System (ADS)

Sleiman, A.; Rosamond, M. C.; Alba Martin, M.; Ayesh, A.; Al Ghaferi, A.; Gallant, A. J.; Mabrook, M. F.; Zeze, D. A.

2012-01-01

A pentacene-based organic metal-insulator-semiconductor memory device, utilizing single walled carbon nanotubes (SWCNTs) for charge storage is reported. SWCNTs were embedded, between SU8 and polymethylmethacrylate to achieve an efficient encapsulation. The devices exhibit capacitance-voltage clockwise hysteresis with a 6 V memory window at ± 30 V sweep voltage, attributed to charging and discharging of SWCNTs. As the applied gate voltage exceeds the SU8 breakdown voltage, charge leakage is induced in SU8 to allow more charges to be stored in the SWCNT nodes. The devices exhibited high storage density (˜9.15 × 1011 cm-2) and demonstrated 94% charge retention due to the superior encapsulation.

Ferroelectric symmetry-protected multibit memory cell

NASA Astrophysics Data System (ADS)

Baudry, Laurent; Lukyanchuk, Igor; Vinokur, Valerii M.

2017-02-01

The tunability of electrical polarization in ferroelectrics is instrumental to their applications in information-storage devices. The existing ferroelectric memory cells are based on the two-level storage capacity with the standard binary logics. However, the latter have reached its fundamental limitations. Here we propose ferroelectric multibit cells (FMBC) utilizing the ability of multiaxial ferroelectric materials to pin the polarization at a sequence of the multistable states. Employing the catastrophe theory principles we show that these states are symmetry-protected against the information loss and thus realize novel topologically-controlled access memory (TAM). Our findings enable developing a platform for the emergent many-valued non-Boolean information technology and target challenges posed by needs of quantum and neuromorphic computing.

Overview of emerging nonvolatile memory technologies

PubMed Central

2014-01-01

Nonvolatile memory technologies in Si-based electronics date back to the 1990s. Ferroelectric field-effect transistor (FeFET) was one of the most promising devices replacing the conventional Flash memory facing physical scaling limitations at those times. A variant of charge storage memory referred to as Flash memory is widely used in consumer electronic products such as cell phones and music players while NAND Flash-based solid-state disks (SSDs) are increasingly displacing hard disk drives as the primary storage device in laptops, desktops, and even data centers. The integration limit of Flash memories is approaching, and many new types of memory to replace conventional Flash memories have been proposed. Emerging memory technologies promise new memories to store more data at less cost than the expensive-to-build silicon chips used by popular consumer gadgets including digital cameras, cell phones and portable music players. They are being investigated and lead to the future as potential alternatives to existing memories in future computing systems. Emerging nonvolatile memory technologies such as magnetic random-access memory (MRAM), spin-transfer torque random-access memory (STT-RAM), ferroelectric random-access memory (FeRAM), phase-change memory (PCM), and resistive random-access memory (RRAM) combine the speed of static random-access memory (SRAM), the density of dynamic random-access memory (DRAM), and the nonvolatility of Flash memory and so become very attractive as another possibility for future memory hierarchies. Many other new classes of emerging memory technologies such as transparent and plastic, three-dimensional (3-D), and quantum dot memory technologies have also gained tremendous popularity in recent years. Subsequently, not an exaggeration to say that computer memory could soon earn the ultimate commercial validation for commercial scale-up and production the cheap plastic knockoff. Therefore, this review is devoted to the rapidly developing new class of memory technologies and scaling of scientific procedures based on an investigation of recent progress in advanced Flash memory devices. PMID:25278820

Overview of emerging nonvolatile memory technologies.

PubMed

Meena, Jagan Singh; Sze, Simon Min; Chand, Umesh; Tseng, Tseung-Yuen

2014-01-01

Nonvolatile memory technologies in Si-based electronics date back to the 1990s. Ferroelectric field-effect transistor (FeFET) was one of the most promising devices replacing the conventional Flash memory facing physical scaling limitations at those times. A variant of charge storage memory referred to as Flash memory is widely used in consumer electronic products such as cell phones and music players while NAND Flash-based solid-state disks (SSDs) are increasingly displacing hard disk drives as the primary storage device in laptops, desktops, and even data centers. The integration limit of Flash memories is approaching, and many new types of memory to replace conventional Flash memories have been proposed. Emerging memory technologies promise new memories to store more data at less cost than the expensive-to-build silicon chips used by popular consumer gadgets including digital cameras, cell phones and portable music players. They are being investigated and lead to the future as potential alternatives to existing memories in future computing systems. Emerging nonvolatile memory technologies such as magnetic random-access memory (MRAM), spin-transfer torque random-access memory (STT-RAM), ferroelectric random-access memory (FeRAM), phase-change memory (PCM), and resistive random-access memory (RRAM) combine the speed of static random-access memory (SRAM), the density of dynamic random-access memory (DRAM), and the nonvolatility of Flash memory and so become very attractive as another possibility for future memory hierarchies. Many other new classes of emerging memory technologies such as transparent and plastic, three-dimensional (3-D), and quantum dot memory technologies have also gained tremendous popularity in recent years. Subsequently, not an exaggeration to say that computer memory could soon earn the ultimate commercial validation for commercial scale-up and production the cheap plastic knockoff. Therefore, this review is devoted to the rapidly developing new class of memory technologies and scaling of scientific procedures based on an investigation of recent progress in advanced Flash memory devices.

Twisting Tongues and Memories: Explorations of the Relationship between Language Production and Verbal Working Memory

ERIC Educational Resources Information Center

Acheson, Daniel J.; MacDonald, Maryellen C.

2009-01-01

Many accounts of working memory posit specialized storage mechanisms for the maintenance of serial order. We explore an alternative, that maintenance is achieved through temporary activation in the language production architecture. Four experiments examined the extent to which the phonological similarity effect can be explained as a sublexical…

The Roles of Working Memory and Cognitive Load in Geoscience Learning

ERIC Educational Resources Information Center

Jaeger, Allison J.; Shipley, Thomas F.; Reynolds, Stephen J.

2017-01-01

Working memory is a cognitive system that allows for the simultaneous storage and processing of active information. While working memory has been implicated as an important element for success in many science, technology, engineering, and mathematics (STEM) fields, its specific role in geoscience learning is not fully understood. The major goal of…

Working Memory and Fluid Intelligence in Young Children

ERIC Educational Resources Information Center

Engel de Abreu, Pascale M. J.; Conway, Andrew R. A.; Gathercole, Susan E.

2010-01-01

The present study investigates how working memory and fluid intelligence are related in young children and how these links develop over time. The major aim is to determine which aspect of the working memory system--short-term storage or cognitive control--drives the relationship with fluid intelligence. A sample of 119 children was followed from…

An outline for the analysis of dementia. The memory disorder of Huntingtons disease.

PubMed

Caine, E D; Ebert, M H; Weingartner, H

1977-11-01

Methods have been developed for assessing the cognitive parameters contributing to a memory disorder. Our findings suggest that individuals with Huntington disease have impairments in the encoding of new information and the consistent retrieval from storage of learned material. Their difficulties lie particularly in the realm of episodic memory.

Verbal Working Memory Performance Correlates with Regional White Matter Structures in the Frontoparietal Regions

ERIC Educational Resources Information Center

Takeuchi, Hikaru; Taki, Yasuyuki; Sassa, Yuko; Hashizume, Hiroshi; Sekiguchi, Atsushi; Fukushima, Ai; Kawashima, Ryuta

2011-01-01

Working memory is the limited capacity storage system involved in the maintenance and manipulation of information over short periods of time. Previous imaging studies have suggested that the frontoparietal regions are activated during working memory tasks; a putative association between the structure of the frontoparietal regions and working…

The Co-Evolution of Knowledge and Event Memory

ERIC Educational Resources Information Center

Nelson, Angela B.; Shiffrin, Richard M.

2013-01-01

We present a theoretical framework and a simplified simulation model for the co-evolution of knowledge and event memory, both termed SARKAE (Storing and Retrieving Knowledge and Events). Knowledge is formed through the accrual of individual events, a process that operates in tandem with the storage of individual event memories. In 2 studies, new…

Systems and methods to control multiple peripherals with a single-peripheral application code

DOEpatents

Ransom, Ray M.

2013-06-11

Methods and apparatus are provided for enhancing the BIOS of a hardware peripheral device to manage multiple peripheral devices simultaneously without modifying the application software of the peripheral device. The apparatus comprises a logic control unit and a memory in communication with the logic control unit. The memory is partitioned into a plurality of ranges, each range comprising one or more blocks of memory, one range being associated with each instance of the peripheral application and one range being reserved for storage of a data pointer related to each peripheral application of the plurality. The logic control unit is configured to operate multiple instances of the control application by duplicating one instance of the peripheral application for each peripheral device of the plurality and partitioning a memory device into partitions comprising one or more blocks of memory, one partition being associated with each instance of the peripheral application. The method then reserves a range of memory addresses for storage of a data pointer related to each peripheral device of the plurality, and initializes each of the plurality of peripheral devices.

DNA methylation in memory formation: Emerging insights

PubMed Central

Heyward, Frankie D.; Sweatt, J. David

2016-01-01

The establishment of synaptic plasticity and long-term memory requires lasting cellular and molecular modifications that, as a whole, must endure despite the rapid turnover of their constituent parts. Such a molecular feat must be mediated by a stable, self-perpetuating, cellular information storage mechanism. DNA methylation, being the archetypal cellular information storage mechanism, has been heavily implicated as being necessary for stable activity-dependent transcriptional alterations within the central nervous system (CNS). This review details the foundational discoveries from both gene-targeted, as well as whole-genome sequencing, studies that have successfully brought DNA methylation to our attention as a chief regulator of activity- and experience-dependent transcriptional alterations within the CNS. We present a hypothetical framework with which the disparate experimental findings dealing with distinct manipulations of the DNA methylation, and their effect on memory, might be resolved while taking into account the unique impact activity-dependent alterations in DNA methylation potentially have on both memory promoting and memory-suppressing gene expression. And last, we discuss potential avenues for future inquiry into the role of DNA methylation during remote memory formation. PMID:25832671

Imaging standards for smart cards

NASA Astrophysics Data System (ADS)

Ellson, Richard N.; Ray, Lawrence A.

1996-02-01

"Smart cards" are plastic cards the size of credit cards which contain integrated circuits for the storage of digital information. The applications of these cards for image storage has been growing as card data capacities have moved from tens of bytes to thousands of bytes. This has prompted the recommendation of standards by the X3B10 committee of ANSI for inclusion in ISO standards for card image storage of a variety of image data types including digitized signatures and color portrait images. This paper will review imaging requirements of the smart card industry, challenges of image storage for small memory devices, card image communications, and the present status of standards. The paper will conclude with recommendations for the evolution of smart card image standards towards image formats customized to the image content and more optimized for smart card memory constraints.

Imaging standards for smart cards

NASA Astrophysics Data System (ADS)

Ellson, Richard N.; Ray, Lawrence A.

1996-01-01

'Smart cards' are plastic cards the size of credit cards which contain integrated circuits for the storage of digital information. The applications of these cards for image storage has been growing as card data capacities have moved from tens of bytes to thousands of bytes. This has prompted the recommendation of standards by the X3B10 committee of ANSI for inclusion in ISO standards for card image storage of a variety of image data types including digitized signatures and color portrait images. This paper reviews imaging requirements of the smart card industry, challenges of image storage for small memory devices, card image communications, and the present status of standards. The paper concludes with recommendations for the evolution of smart card image standards towards image formats customized to the image content and more optimized for smart card memory constraints.

Reconstructions of information in visual spatial working memory degrade with memory load.

PubMed

Sprague, Thomas C; Ester, Edward F; Serences, John T

2014-09-22

Working memory (WM) enables the maintenance and manipulation of information relevant to behavioral goals. Variability in WM ability is strongly correlated with IQ [1], and WM function is impaired in many neurological and psychiatric disorders [2, 3], suggesting that this system is a core component of higher cognition. WM storage is thought to be mediated by patterns of activity in neural populations selective for specific properties (e.g., color, orientation, location, and motion direction) of memoranda [4-13]. Accordingly, many models propose that differences in the amplitude of these population responses should be related to differences in memory performance [14, 15]. Here, we used functional magnetic resonance imaging and an image reconstruction technique based on a spatial encoding model [16] to visualize and quantify population-level memory representations supported by multivoxel patterns of activation within regions of occipital, parietal and frontal cortex while participants precisely remembered the location(s) of zero, one, or two small stimuli. We successfully reconstructed images containing representations of the remembered-but not forgotten-locations within regions of occipital, parietal, and frontal cortex using delay-period activation patterns. Critically, the amplitude of representations of remembered locations and behavioral performance both decreased with increasing memory load. These results suggest that differences in visual WM performance between memory load conditions are mediated by changes in the fidelity of large-scale population response profiles distributed across multiple areas of human cortex. Copyright © 2014 Elsevier Ltd. All rights reserved.

Growth in literacy, cognition, and working memory in English language learners.

PubMed

Lee Swanson, H; Orosco, Michael J; Lussier, Catherine M

2015-04-01

This cohort sequential study explored the components of working memory that underlie English reading and language acquisition in elementary school children whose first language is Spanish. To this end, children (N=410) in Grades 1, 2, and 3 at Wave 1 were administered a battery of cognitive (short-term memory [STM], working memory [WM], rapid naming, phonological processing, and random letter and number generation), vocabulary, and reading measures in both Spanish and English. These same measures were administered 1 and 2 years later. The results showed that (a) a three-factor structure (phonological STM, visual-spatial WM, and verbal WM) captured the data within both language systems, (b) growth in both the executive and STM storage components was uniquely related to growth in second language (L2) reading and language acquisition, and (c) the contribution of growth in the executive component of WM to growth in L2 processing was independent of growth in storage, phonological knowledge, inhibition, and rapid naming speed. The results suggested that growth in the phonological storage system does not supersede growth of the executive component of WM as a major contributor to growth in children's L2 reading and language. Copyright © 2015 Elsevier Inc. All rights reserved.

Nanoscale thermal cross-talk effect on phase-change probe memory.

PubMed

Wang, Lei; Wen, Jing; Xiong, Bangshu

2018-05-14

Phase-change probe memory is considered as one of the most promising means for next-generation mass storage devices. However, the achievable storage density of phase-change probe memory is drastically affected by the resulting thermal cross-talk effect while previously lacking of detailed study. Therefore, a three dimensional model that couples electrical, thermal, and phase-change processes of the Ge2Sb2Te5 media is developed, and subsequently deployed to assess the thermal cross-talk effect based on Si/TiN/ Ge2Sb2Te5/diamond-like carbon structure by appropriately tailoring the electro-thermal and geometrical properties of the storage media stack for a variety of external excitations. The modeling results show that the diamond-like carbon capping with a thin thickness, a high electrical conductivity, and a low thermal conductivity is desired to minimize the thermal cross-talk, while the TiN underlayer has a slight impact on the thermal cross-talk. Combining the modeling findings with the previous film deposition experience, an optimized phase-change probe memory architecture is presented, and its capability of providing ultra-high recording density simultaneously with a sufficiently low thermal cross-talk is demonstrated. . © 2018 IOP Publishing Ltd.

Enhanced storage capacity with errors in scale-free Hopfield neural networks: An analytical study.

PubMed

Kim, Do-Hyun; Park, Jinha; Kahng, Byungnam

2017-01-01

The Hopfield model is a pioneering neural network model with associative memory retrieval. The analytical solution of the model in mean field limit revealed that memories can be retrieved without any error up to a finite storage capacity of O(N), where N is the system size. Beyond the threshold, they are completely lost. Since the introduction of the Hopfield model, the theory of neural networks has been further developed toward realistic neural networks using analog neurons, spiking neurons, etc. Nevertheless, those advances are based on fully connected networks, which are inconsistent with recent experimental discovery that the number of connections of each neuron seems to be heterogeneous, following a heavy-tailed distribution. Motivated by this observation, we consider the Hopfield model on scale-free networks and obtain a different pattern of associative memory retrieval from that obtained on the fully connected network: the storage capacity becomes tremendously enhanced but with some error in the memory retrieval, which appears as the heterogeneity of the connections is increased. Moreover, the error rates are also obtained on several real neural networks and are indeed similar to that on scale-free model networks.

Gravin orchestrates PKA and β2-adrenergic receptor signaling critical for synaptic plasticity and memory

PubMed Central

Havekes, Robbert; Canton, David A.; Park, Alan J.; Huang, Ted; Nie, Ting; Day, Jonathan P.; Guercio, Leonardo A.; Grimes, Quinn; Luczak, Vincent; Gelman, Irwin H.; Baillie, George S.; Scott, John D.; Abel, Ted

2012-01-01

A kinase-anchoring proteins (AKAPs) organize compartmentalized pools of Protein Kinase A (PKA) to enable localized signaling events within neurons. However, it is unclear which of the many expressed AKAPs in neurons target PKA to signaling complexes important for long-lasting forms of synaptic plasticity and memory storage. In the forebrain, the anchoring protein gravin recruits a signaling complex containing PKA, PKC, calmodulin, and PDE4D to the β2-adrenergic receptor. Here, we show that mice lacking the α-isoform of gravin have deficits in PKA-dependent long-lasting forms of hippocampal synaptic plasticity including β2-adrenergic receptor-mediated plasticity, and selective impairments of long-term memory storage. Further, both hippocampal β2-adrenergic receptor phosphorylation by PKA, and learning-induced activation of ERK, are attenuated in the CA1 region of the hippocampus in mice lacking gravin-α. We conclude that gravin compartmentalizes a significant pool of PKA that regulates learning-induced β2-adrenergic receptor signaling and ERK activation in the hippocampus in vivo, organizing molecular interactions between glutamatergic and noradrenergic signaling pathways for long-lasting synaptic plasticity, and memory storage. PMID:23238728

Expanded interleaved solid-state memory for a wide bandwidth transient waveform recorder

NASA Technical Reports Server (NTRS)

Thomas, R. M., Jr.

1980-01-01

An interleaved, solid state expanded memory for a 100 MHz bandwidth waveform recorder is described. The memory development resulted in a significant increase in the storage capacity of a commercially available recorder. The motivation for the memory expansion of the waveform recorder, which is used to support in-flight measurement of the electromagnetic characteristics of lightning discharges, was the need for a significantly longer data window than that provided by the commercially available unit. The expanded recorder provides a data window that is 128 times longer than the commercial unit, while maintaining the same time resolution, by increasing the storage capacity from 1024 to 131 072 data samples. The expanded unit operates at sample periods as small as 10 ns. Sampling once every 10 ns, the commercial unit records for about 10 microseconds before the memory is filled, whereas, the expanded unit records for about 1300 microseconds. A photo of the expanded waveform recorder is shown.

Evidence for two attentional components in visual working memory.

PubMed

Allen, Richard J; Baddeley, Alan D; Hitch, Graham J

2014-11-01

How does executive attentional control contribute to memory for sequences of visual objects, and what does this reveal about storage and processing in working memory? Three experiments examined the impact of a concurrent executive load (backward counting) on memory for sequences of individually presented visual objects. Experiments 1 and 2 found disruptive concurrent load effects of equivalent magnitude on memory for shapes, colors, and colored shape conjunctions (as measured by single-probe recognition). These effects were present only for Items 1 and 2 in a 3-item sequence; the final item was always impervious to this disruption. This pattern of findings was precisely replicated in Experiment 3 when using a cued verbal recall measure of shape-color binding, with error analysis providing additional insights concerning attention-related loss of early-sequence items. These findings indicate an important role for executive processes in maintaining representations of earlier encountered stimuli in an active form alongside privileged storage of the most recent stimulus. PsycINFO Database Record (c) 2014 APA, all rights reserved.

Restoring primacy in amnesic free recall: evidence for the recency theory of primacy.

PubMed

Dewar, Michaela; Brown, Gordon D A; Della Sala, Sergio

2011-09-01

Primacy and recency effects at immediate recall are thought to reflect the independent functioning of a long-term memory store (primacy) and a short-term memory store (recency). Key evidence for this theory comes from amnesic patients who show severe long-term memory storage deficits, coupled with profoundly attenuated primacy. Here we challenge this dominant dual-store theory of immediate recall by demonstrating that attenuated primacy in amnesic patients can reflect abnormal working memory rehearsal processes. D.A., a patient with severe amnesia, presented with profoundly attenuated primacy when using her preferred atypical noncumulative rehearsal strategy. In contrast, despite her severe amnesia, she showed normal primacy when her rehearsal was matched with that of controls via an externalized cumulative rehearsal schedule. Our data are in keeping with the "recency theory of primacy" and suggest that primacy at immediate recall is dependent upon medial temporal lobe involvement in cumulative rehearsal rather than long-term memory storage.

Electrochromic conductive polymer fuses for hybrid organic/inorganic semiconductor memories

NASA Astrophysics Data System (ADS)

Möller, Sven; Forrest, Stephen R.; Perlov, Craig; Jackson, Warren; Taussig, Carl

2003-12-01

We demonstrate a nonvolatile, write-once-read-many-times (WORM) memory device employing a hybrid organic/inorganic semiconductor architecture consisting of thin film p-i-n silicon diode on a stainless steel substrate integrated in series with a conductive polymer fuse. The nonlinearity of the silicon diodes enables a passive matrix memory architecture, while the conductive polyethylenedioxythiophene:polystyrene sulfonic acid polymer serves as a reliable switch with fuse-like behavior for data storage. The polymer can be switched at ˜2 μs, resulting in a permanent decrease of conductivity of the memory pixel by up to a factor of 103. The switching mechanism is primarily due to a current and thermally dependent redox reaction in the polymer, limited by the double injection of both holes and electrons. The switched device performance does not degrade after many thousand read cycles in ambient at room temperature. Our results suggest that low cost, organic/inorganic WORM memories are feasible for light weight, high density, robust, and fast archival storage applications.

Improved performance of Ta2O5-x resistive switching memory by Gd-doping: Ultralow power operation, good data retention, and multilevel storage

NASA Astrophysics Data System (ADS)

Shi, K. X.; Xu, H. Y.; Wang, Z. Q.; Zhao, X. N.; Liu, W. Z.; Ma, J. G.; Liu, Y. C.

2017-11-01

Resistive-switching memory with ultralow-power consumption is very promising technology for next-generation data storage and high-energy-efficiency neurosynaptic chips. Herein, Ta2O5-x-based multilevel memories with ultralow-power consumption and good data retention were achieved by simple Gd-doping. The introduction of a Gd ion, as an oxygen trapper, not only suppresses the generation of oxygen vacancy defects and greatly increases the Ta2O5-x resistance but also increases the oxygen-ion migration barrier. As a result, the memory cells can operate at an ultralow current of 1 μA with the extrapolated retention time of >10 years at 85 °C and the high switching speeds of 10 ns/40 ns for SET/RESET processes. The energy consumption of the device is as low as 60 fJ/bit, which is comparable to emerging ultralow-energy consumption (<100 fJ/bit) memory devices.

Integration of lead-free ferroelectric on HfO2/Si (100) for high performance non-volatile memory applications

PubMed Central

Kundu, Souvik; Maurya, Deepam; Clavel, Michael; Zhou, Yuan; Halder, Nripendra N.; Hudait, Mantu K.; Banerji, Pallab; Priya, Shashank

2015-01-01

We introduce a novel lead-free ferroelectric thin film (1-x)BaTiO3-xBa(Cu1/3Nb2/3)O3 (x = 0.025) (BT-BCN) integrated on to HfO2 buffered Si for non-volatile memory (NVM) applications. Piezoelectric force microscopy (PFM), x-ray diffraction, and high resolution transmission electron microscopy were employed to establish the ferroelectricity in BT-BCN thin films. PFM study reveals that the domains reversal occurs with 180° phase change by applying external voltage, demonstrating its effectiveness for NVM device applications. X-ray photoelectron microscopy was used to investigate the band alignments between atomic layer deposited HfO2 and pulsed laser deposited BT-BCN films. Programming and erasing operations were explained on the basis of band-alignments. The structure offers large memory window, low leakage current, and high and low capacitance values that were easily distinguishable even after ~106 s, indicating strong charge storage potential. This study explains a new approach towards the realization of ferroelectric based memory devices integrated on Si platform and also opens up a new possibility to embed the system within current complementary metal-oxide-semiconductor processing technology. PMID:25683062

Biomolecule nanoparticle-induced nanocomposites with resistive switching nonvolatile memory properties

NASA Astrophysics Data System (ADS)

Ko, Yongmin; Ryu, Sook Won; Cho, Jinhan

2016-04-01

Resistive switching behavior-based memory devices are considered promising candidates for next-generation data storage because of their simple structure configuration, low power consumption, and rapid operating speed. Here, the resistive switching nonvolatile memory properties of Fe2O3 nanocomposite (NC) films prepared from the thermal calcination of layer-by-layer (LbL) assembled ferritin multilayers were successfully investigated. For this study, negatively charged ferritin nanoparticles were alternately deposited onto the Pt-coated Si substrate with positively charged poly(allylamine hydrochloride) (PAH) by solution-based electrostatic LbL assembly, and the formed multilayers were thermally calcinated to obtain a homogeneous transition metal oxide NC film through the elimination of organic components, including the protein shell of ferritin. The formed memory device exhibits a stable ON/OFF current ratio of approximately 103, with nanosecond switching times under an applied external bias. In addition, these reversible switching properties were kept stable during the repeated cycling tests of above 200 cycles and a test period of approximately 105 s under atmosphere. These solution-based approaches can provide a basis for large-area inorganic nanoparticle-based electric devices through the design of bio-nanomaterials at the molecular level.

Temporal dynamics of encoding, storage and reallocation of visual working memory

PubMed Central

Bays, Paul M; Gorgoraptis, Nikos; Wee, Natalie; Marshall, Louise; Husain, Masud

2012-01-01

The process of encoding a visual scene into working memory has previously been studied using binary measures of recall. Here we examine the temporal evolution of memory resolution, based on observers’ ability to reproduce the orientations of objects presented in brief, masked displays. Recall precision was accurately described by the interaction of two independent constraints: an encoding limit that determines the maximum rate at which information can be transferred into memory, and a separate storage limit that determines the maximum fidelity with which information can be maintained. Recall variability decreased incrementally with time, consistent with a parallel encoding process in which visual information from multiple objects accumulates simultaneously in working memory. No evidence was observed for a limit on the number of items stored. Cueing one display item with a brief flash led to rapid development of a recall advantage for that item. This advantage was short-lived if the cue was simply a salient visual event, but was maintained if it indicated an object of particular relevance to the task. These cueing effects were observed even for items that had already been encoded into memory, indicating that limited memory resources can be rapidly reallocated to prioritize salient or goal-relevant information. PMID:21911739

Verbal Working Memory in Children With Cochlear Implants

PubMed Central

Caldwell-Tarr, Amanda; Low, Keri E.; Lowenstein, Joanna H.

2017-01-01

Purpose Verbal working memory in children with cochlear implants and children with normal hearing was examined. Participants Ninety-three fourth graders (47 with normal hearing, 46 with cochlear implants) participated, all of whom were in a longitudinal study and had working memory assessed 2 years earlier. Method A dual-component model of working memory was adopted, and a serial recall task measured storage and processing. Potential predictor variables were phonological awareness, vocabulary knowledge, nonverbal IQ, and several treatment variables. Potential dependent functions were literacy, expressive language, and speech-in-noise recognition. Results Children with cochlear implants showed deficits in storage and processing, similar in size to those at second grade. Predictors of verbal working memory differed across groups: Phonological awareness explained the most variance in children with normal hearing; vocabulary explained the most variance in children with cochlear implants. Treatment variables explained little of the variance. Where potentially dependent functions were concerned, verbal working memory accounted for little variance once the variance explained by other predictors was removed. Conclusions The verbal working memory deficits of children with cochlear implants arise due to signal degradation, which limits their abilities to acquire phonological awareness. That hinders their abilities to store items using a phonological code. PMID:29075747

Temporal dynamics of encoding, storage, and reallocation of visual working memory.

PubMed

Bays, Paul M; Gorgoraptis, Nikos; Wee, Natalie; Marshall, Louise; Husain, Masud

2011-09-12

The process of encoding a visual scene into working memory has previously been studied using binary measures of recall. Here, we examine the temporal evolution of memory resolution, based on observers' ability to reproduce the orientations of objects presented in brief, masked displays. Recall precision was accurately described by the interaction of two independent constraints: an encoding limit that determines the maximum rate at which information can be transferred into memory and a separate storage limit that determines the maximum fidelity with which information can be maintained. Recall variability decreased incrementally with time, consistent with a parallel encoding process in which visual information from multiple objects accumulates simultaneously in working memory. No evidence was observed for a limit on the number of items stored. Cuing one display item with a brief flash led to rapid development of a recall advantage for that item. This advantage was short-lived if the cue was simply a salient visual event but was maintained if it indicated an object of particular relevance to the task. These cuing effects were observed even for items that had already been encoded into memory, indicating that limited memory resources can be rapidly reallocated to prioritize salient or goal-relevant information.

Strategic trade-offs between quantity and quality in working memory.

PubMed

Fougnie, Daryl; Cormiea, Sarah M; Kanabar, Anish; Alvarez, George A

2016-08-01

Is working memory capacity determined by an immutable limit-for example, 4 memory storage slots? The fact that performance is typically unaffected by task instructions has been taken as support for such structural models of memory. Here, we modified a standard working memory task to incentivize participants to remember more items. Participants were asked to remember a set of colors over a short retention interval. In 1 condition, participants reported a random item's color using a color wheel. In the modified task, participants responded to all items and their response was only considered correct if all responses were on the correct half of the color wheel. We looked for a trade-off between quantity and quality-participants storing more items, but less precisely, when required to report them all. This trade-off was observed when tasks were blocked and when task-type was cued after encoding, but not when task-type was cued during the response, suggesting that task differences changed how items were actively encoded and maintained. This strategic control over the contents of working memory challenges models that assume inflexible limits on memory storage. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

[Artificial intelligence meeting neuropsychology. Semantic memory in normal and pathological aging].

PubMed

Aimé, Xavier; Charlet, Jean; Maillet, Didier; Belin, Catherine

2015-03-01

Artificial intelligence (IA) is the subject of much research, but also many fantasies. It aims to reproduce human intelligence in its learning capacity, knowledge storage and computation. In 2014, the Defense Advanced Research Projects Agency (DARPA) started the restoring active memory (RAM) program that attempt to develop implantable technology to bridge gaps in the injured brain and restore normal memory function to people with memory loss caused by injury or disease. In another IA's field, computational ontologies (a formal and shared conceptualization) try to model knowledge in order to represent a structured and unambiguous meaning of the concepts of a target domain. The aim of these structures is to ensure a consensual understanding of their meaning and a univariant use (the same concept is used by all to categorize the same individuals). The first representations of knowledge in the AI's domain are largely based on model tests of semantic memory. This one, as a component of long-term memory is the memory of words, ideas, concepts. It is the only declarative memory system that resists so remarkably to the effects of age. In contrast, non-specific cognitive changes may decrease the performance of elderly in various events and instead report difficulties of access to semantic representations that affect the semantics stock itself. Some dementias, like semantic dementia and Alzheimer's disease, are linked to alteration of semantic memory. We propose in this paper, using the computational ontologies model, a formal and relatively thin modeling, in the service of neuropsychology: 1) for the practitioner with decision support systems, 2) for the patient as cognitive prosthesis outsourced, and 3) for the researcher to study semantic memory.

Associative memory in an analog iterated-map neural network

NASA Astrophysics Data System (ADS)

Marcus, C. M.; Waugh, F. R.; Westervelt, R. M.

1990-03-01

The behavior of an analog neural network with parallel dynamics is studied analytically and numerically for two associative-memory learning algorithms, the Hebb rule and the pseudoinverse rule. Phase diagrams in the parameter space of analog gain β and storage ratio α are presented. For both learning rules, the networks have large ``recall'' phases in which retrieval states exist and convergence to a fixed point is guaranteed by a global stability criterion. We also demonstrate numerically that using a reduced analog gain increases the probability of recall starting from a random initial state. This phenomenon is comparable to thermal annealing used to escape local minima but has the advantage of being deterministic, and therefore easily implemented in electronic hardware. Similarities and differences between analog neural networks and networks with two-state neurons at finite temperature are also discussed.

Efficient multitasking of Choleski matrix factorization on CRAY supercomputers

NASA Technical Reports Server (NTRS)

Overman, Andrea L.; Poole, Eugene L.

1991-01-01

A Choleski method is described and used to solve linear systems of equations that arise in large scale structural analysis. The method uses a novel variable-band storage scheme and is structured to exploit fast local memory caches while minimizing data access delays between main memory and vector registers. Several parallel implementations of this method are described for the CRAY-2 and CRAY Y-MP computers demonstrating the use of microtasking and autotasking directives. A portable parallel language, FORCE, is used for comparison with the microtasked and autotasked implementations. Results are presented comparing the matrix factorization times for three representative structural analysis problems from runs made in both dedicated and multi-user modes on both computers. CPU and wall clock timings are given for the parallel implementations and are compared to single processor timings of the same algorithm.

An adaptive vector quantization scheme

NASA Technical Reports Server (NTRS)

Cheung, K.-M.

1990-01-01

Vector quantization is known to be an effective compression scheme to achieve a low bit rate so as to minimize communication channel bandwidth and also to reduce digital memory storage while maintaining the necessary fidelity of the data. However, the large number of computations required in vector quantizers has been a handicap in using vector quantization for low-rate source coding. An adaptive vector quantization algorithm is introduced that is inherently suitable for simple hardware implementation because it has a simple architecture. It allows fast encoding and decoding because it requires only addition and subtraction operations.

Testing episodic memory in animals: a new approach.

PubMed

Griffiths, D P; Clayton, N S

2001-08-01

Episodic memory involves the encoding and storage of memories concerned with unique personal experiences and their subsequent recall, and it has long been the subject of intensive investigation in humans. According to Tulving's classical definition, episodic memory "receives and stores information about temporally dated episodes or events and temporal-spatial relations among these events." Thus, episodic memory provides information about the 'what' and 'when' of events ('temporally dated experiences') and about 'where' they happened ('temporal-spatial relations'). The storage and subsequent recall of this episodic information was thought to be beyond the memory capabilities of nonhuman animals. Although there are many laboratory procedures for investigating memory for discrete past episodes, until recently there were no previous studies that fully satisfied the criteria of Tulving's definition: they can all be explained in much simpler terms than episodic memory. However, current studies of memory for cache sites in food-storing jays provide an ethologically valid model for testing episodic-like memory in animals, thereby bridging the gap between human and animal studies memory. There is now a pressing need to adapt these experimental tests of episodic memory for other animals. Given the potential power of transgenic and knock-out procedures for investigating the genetic and molecular bases of learning and memory in laboratory rodents, not to mention the wealth of knowledge about the neuroanatomy and neurophysiology of the rodent hippocampus (a brain area heavily implicated in episodic memory), an obvious next step is to develop a rodent model of episodic-like memory based on the food-storing bird paradigm. The development of a rodent model system could make an important contribution to our understanding of the neural, molecular, and behavioral mechanisms of mammalian episodic memory.

Multiplexed Holographic Data Storage in Bacteriorhodopsin

NASA Technical Reports Server (NTRS)

Mehrl, David J.; Krile, Thomas F.

1999-01-01

Biochrome photosensitive films in particular Bacteriorhodopsin exhibit features which make these materials an attractive recording medium for optical data storage and processing. Bacteriorhodopsin films find numerous applications in a wide range of optical data processing applications; however the short-term memory characteristics of BR limits their applications for holographic data storage. The life-time of the BR can be extended using cryogenic temperatures [1], although this method makes the system overly complicated and unstable. Longer life-times can be provided in one modification of BR - the "blue" membrane BR [2], however currently available films are characterized by both low diffraction efficiency and difficulties in providing photoreversible recording. In addition, as a dynamic recording material, the BR requires different wavelengths for recording and reconstructing of optical data in order to prevent the information erasure during its readout. This fact also put constraints on a BR-based Optical Memory, due to information loss in holographic memory systems employing the two-lambda technique for reading-writing thick multiplexed holograms.

Visual working memory capacity increases between ages 3 and 8 years, controlling for gains in attention, perception, and executive control.

PubMed

Pailian, Hrag; Libertus, Melissa E; Feigenson, Lisa; Halberda, Justin

2016-08-01

Research in adults has aimed to characterize constraints on the capacity of Visual Working Memory (VWM), in part because of the system's broader impacts throughout cognition. However, less is known about how VWM develops in childhood. Existing work has reached conflicting conclusions as to whether VWM storage capacity increases after infancy, and if so, when and by how much. One challenge is that previous studies did not control for developmental changes in attention and executive processing, which also may undergo improvement. We investigated the development of VWM storage capacity in children from 3 to 8 years of age, and in adults, while controlling for developmental change in exogenous and endogenous attention and executive control. Our results reveal that, when controlling for improvements in these abilities, VWM storage capacity increases across development and approaches adult-like levels between ages 6 and 8 years. More generally, this work highlights the value of estimating working memory, attention, perception, and decision-making components together.

The effects of aging on the working memory processes of multimodal information.

PubMed

Solesio-Jofre, Elena; López-Frutos, José María; Cashdollar, Nathan; Aurtenetxe, Sara; de Ramón, Ignacio; Maestú, Fernando

2017-05-01

Normal aging is associated with deficits in working memory processes. However, the majority of research has focused on storage or inhibitory processes using unimodal paradigms, without addressing their relationships using different sensory modalities. Hence, we pursued two objectives. First, was to examine the effects of aging on storage and inhibitory processes. Second, was to evaluate aging effects on multisensory integration of visual and auditory stimuli. To this end, young and older participants performed a multimodal task for visual and auditory pairs of stimuli with increasing memory load at encoding and interference during retention. Our results showed an age-related increased vulnerability to interrupting and distracting interference reflecting inhibitory deficits related to the off-line reactivation and on-line suppression of relevant and irrelevant information, respectively. Storage capacity was impaired with increasing task demands in both age groups. Additionally, older adults showed a deficit in multisensory integration, with poorer performance for new visual compared to new auditory information.

Addressable configurations of DNA nanostructures for rewritable memory

PubMed Central

Levchenko, Oksana; Patel, Dhruv S.; MacIsaac, Molly

2017-01-01

Abstract DNA serves as nature's information storage molecule, and has been the primary focus of engineered systems for biological computing and data storage. Here we combine recent efforts in DNA self-assembly and toehold-mediated strand displacement to develop a rewritable multi-bit DNA memory system. The system operates by encoding information in distinct and reversible conformations of a DNA nanoswitch and decoding by gel electrophoresis. We demonstrate a 5-bit system capable of writing, erasing, and rewriting binary representations of alphanumeric symbols, as well as compatibility with ‘OR’ and ‘AND’ logic operations. Our strategy is simple to implement, requiring only a single mixing step at room temperature for each operation and standard gel electrophoresis to read the data. We envision such systems could find use in covert product labeling and barcoding, as well as secure messaging and authentication when combined with previously developed encryption strategies. Ultimately, this type of memory has exciting potential in biomedical sciences as data storage can be coupled to sensing of biological molecules. PMID:28977499

A highly efficient silole-containing dithienylethene with excellent thermal stability and fatigue resistance: a promising candidate for optical memory storage materials.

PubMed

Chan, Jacky Chi-Hung; Lam, Wai Han; Yam, Vivian Wing-Wah

2014-12-10

Diarylethene compounds are potential candidates for applications in optical memory storage systems and photoswitchable molecular devices; however, they usually show low photocycloreversion quantum yields, which result in ineffective erasure processes. Here, we present the first highly efficient photochromic silole-containing dithienylethene with excellent thermal stability and fatigue resistance. The photochemical quantum yields for photocyclization and photocycloreversion of the compound are found to be high and comparable to each other; the latter of which is rarely found in diarylethene compounds. These would give rise to highly efficient photoswitchable material with effective writing and erasure processes. Incorporation of the silole moiety as a photochromic dithienylethene backbone also was demonstrated to enhance the thermal stability of the closed form, in which the thermal backward reaction to the open form was found to be negligible even at 100 °C, which leads to a promising candidate for use as photoswitchable materials and optical memory storage.

Decoding the content of visual short-term memory under distraction in occipital and parietal areas.

PubMed

Bettencourt, Katherine C; Xu, Yaoda

2016-01-01

Recent studies have provided conflicting accounts regarding where in the human brain visual short-term memory (VSTM) content is stored, with strong univariate fMRI responses being reported in superior intraparietal sulcus (IPS), but robust multivariate decoding being reported in occipital cortex. Given the continuous influx of information in everyday vision, VSTM storage under distraction is often required. We found that neither distractor presence nor predictability during the memory delay affected behavioral performance. Similarly, superior IPS exhibited consistent decoding of VSTM content across all distractor manipulations and had multivariate responses that closely tracked behavioral VSTM performance. However, occipital decoding of VSTM content was substantially modulated by distractor presence and predictability. Furthermore, we found no effect of target-distractor similarity on VSTM behavioral performance, further challenging the role of sensory regions in VSTM storage. Overall, consistent with previous univariate findings, our results indicate that superior IPS, but not occipital cortex, has a central role in VSTM storage.

Optically Addressable, Ferroelectric Memory With NDRO

NASA Technical Reports Server (NTRS)

Thakoor, Sarita

1994-01-01

For readout, memory cells addressed via on-chip semiconductor lasers. Proposed thin-film ferroelectric memory device features nonvolatile storage, optically addressable, nondestructive readout (NDRO) with fast access, and low vulnerability to damage by ionizing radiation. Polarization switched during recording and erasure, but not during readout. As result, readout would not destroy contents of memory, and operating life in specific "read-intensive" applications increased up to estimated 10 to the 16th power cycles.

Stream-based Hebbian eigenfilter for real-time neuronal spike discrimination

PubMed Central

2012-01-01

Background Principal component analysis (PCA) has been widely employed for automatic neuronal spike sorting. Calculating principal components (PCs) is computationally expensive, and requires complex numerical operations and large memory resources. Substantial hardware resources are therefore needed for hardware implementations of PCA. General Hebbian algorithm (GHA) has been proposed for calculating PCs of neuronal spikes in our previous work, which eliminates the needs of computationally expensive covariance analysis and eigenvalue decomposition in conventional PCA algorithms. However, large memory resources are still inherently required for storing a large volume of aligned spikes for training PCs. The large size memory will consume large hardware resources and contribute significant power dissipation, which make GHA difficult to be implemented in portable or implantable multi-channel recording micro-systems. Method In this paper, we present a new algorithm for PCA-based spike sorting based on GHA, namely stream-based Hebbian eigenfilter, which eliminates the inherent memory requirements of GHA while keeping the accuracy of spike sorting by utilizing the pseudo-stationarity of neuronal spikes. Because of the reduction of large hardware storage requirements, the proposed algorithm can lead to ultra-low hardware resources and power consumption of hardware implementations, which is critical for the future multi-channel micro-systems. Both clinical and synthetic neural recording data sets were employed for evaluating the accuracy of the stream-based Hebbian eigenfilter. The performance of spike sorting using stream-based eigenfilter and the computational complexity of the eigenfilter were rigorously evaluated and compared with conventional PCA algorithms. Field programmable logic arrays (FPGAs) were employed to implement the proposed algorithm, evaluate the hardware implementations and demonstrate the reduction in both power consumption and hardware memories achieved by the streaming computing Results and discussion Results demonstrate that the stream-based eigenfilter can achieve the same accuracy and is 10 times more computationally efficient when compared with conventional PCA algorithms. Hardware evaluations show that 90.3% logic resources, 95.1% power consumption and 86.8% computing latency can be reduced by the stream-based eigenfilter when compared with PCA hardware. By utilizing the streaming method, 92% memory resources and 67% power consumption can be saved when compared with the direct implementation of GHA. Conclusion Stream-based Hebbian eigenfilter presents a novel approach to enable real-time spike sorting with reduced computational complexity and hardware costs. This new design can be further utilized for multi-channel neuro-physiological experiments or chronic implants. PMID:22490725

Fully integrated sub 100ps photon counting platform

NASA Astrophysics Data System (ADS)

Buckley, S. J.; Bellis, S. J.; Rosinger, P.; Jackson, J. C.

2007-02-01

Current state of the art high resolution counting modules, specifically designed for high timing resolution applications, are largely based on a computer card format. This has tended to result in a costly solution that is restricted to the computer it resides in. We describe a four channel timing module that interfaces to a computer via a USB port and operates with a resolution of less than 100 picoseconds. The core design of the system is an advanced field programmable gate array (FPGA) interfacing to a precision time interval measurement module, mass memory block and a high speed USB 2.0 serial data port. The FPGA design allows the module to operate in a number of modes allowing both continuous recording of photon events (time-tagging) and repetitive time binning. In time-tag mode the system reports, for each photon event, the high resolution time along with the chronological time (macro time) and the channel ID. The time-tags are uploaded in real time to a host computer via a high speed USB port allowing continuous storage to computer memory of up to 4 millions photons per second. In time-bin mode, binning is carried out with count rates up to 10 million photons per second. Each curve resides in a block of 128,000 time-bins each with a resolution programmable down to less than 100 picoseconds. Each bin has a limit of 65535 hits allowing autonomous curve recording until a bin reaches the maximum count or the system is commanded to halt. Due to the large memory storage, several curves/experiments can be stored in the system prior to uploading to the host computer for analysis. This makes this module ideal for integration into high timing resolution specific applications such as laser ranging and fluorescence lifetime imaging using techniques such as time correlated single photon counting (TCSPC).

Can Imageability Help Us Draw the Line between Storage and Composition?

ERIC Educational Resources Information Center

Prado, Elizabeth L.; Ullman, Michael T.

2009-01-01

Language requires both storage and composition. However, exactly what is retrieved from memory and what is assembled remains controversial, especially for inflected words. Here, "imageability effects" is introduced as a new diagnostic of storage and a complement to frequency effects. In 2 studies of past-tense morphology, more reliable…

Storage Capacity Explains Fluid Intelligence but Executive Control Does Not

ERIC Educational Resources Information Center

Chuderski, Adam; Taraday, Maciej; Necka, Edward; Smolen, Tomasz

2012-01-01

We examined whether fluid intelligence (Gf) is better predicted by the storage capacity of active memory or by the effectiveness of executive control. In two psychometric studies, we measured storage capacity with three kinds of task which required the maintenance of a visual array, the monitoring of simple relations among perceptually available…

Filling the Memory Access Gap: A Case for On-Chip Magnetic Storage

DTIC Science & Technology

1999-11-01

PCs, PDAs, and video camcorders, MEMS-based storage also provides a more robust and lower power solution. Unlike rotating storage, which cannot...goldfish. Just chew and swallow. like a chick in a porno . eww, miracle whip. Now give me the Coke. I think of my happy place, eww, melted tongue

Investigation of fast initialization of spacecraft bubble memory systems

NASA Technical Reports Server (NTRS)

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.

Remote direct memory access

DOEpatents

Archer, Charles J.; Blocksome, Michael A.

2012-12-11

Methods, parallel computers, and computer program products are disclosed for remote direct memory access. Embodiments include transmitting, from an origin DMA engine on an origin compute node to a plurality target DMA engines on target compute nodes, a request to send message, the request to send message specifying a data to be transferred from the origin DMA engine to data storage on each target compute node; receiving, by each target DMA engine on each target compute node, the request to send message; preparing, by each target DMA engine, to store data according to the data storage reference and the data length, including assigning a base storage address for the data storage reference; sending, by one or more of the target DMA engines, an acknowledgment message acknowledging that all the target DMA engines are prepared to receive a data transmission from the origin DMA engine; receiving, by the origin DMA engine, the acknowledgement message from the one or more of the target DMA engines; and transferring, by the origin DMA engine, data to data storage on each of the target compute nodes according to the data storage reference using a single direct put operation.

Cross-linguistic evidence for memory storage costs in filler-gap dependencies with wh-adjuncts

PubMed Central

Stepanov, Arthur; Stateva, Penka

2015-01-01

This study investigates processing of interrogative filler-gap dependencies in which the filler integration site or gap is not directly subcategorized by the verb. This is the case when the wh-filler is a structural adjunct such as how or when rather than subject or object. Two self-paced reading experiments in English and Slovenian provide converging cross-linguistic evidence that wh-adjuncts elicit a kind of memory storage cost similar to that previously shown in the literature for wh-arguments. Experiment 1 investigates the storage costs elicited by the adjunct when in Slovenian, and Experiment 2 the storage costs elicited by how quickly and why in English. The results support the class of theories of storage costs based on the metric in terms of incomplete phrase structure rules or incomplete syntactic head predictions. We also demonstrate that the endpoint of the storage cost for a wh-adjunct filler provides valuable processing evidence for its base structural position, the identification of which remains a rather murky issue in current grammatical research. PMID:26388806