WorldWideScience

Sample records for prefix cache memory

  1. Cache memory modelling method and system

    OpenAIRE

    Posadas Cobo, Héctor; Villar Bonet, Eugenio; Díaz Suárez, Luis

    2011-01-01

    The invention relates to a method for modelling a data cache memory of a destination processor, in order to simulate the behaviour of said data cache memory during the execution of a software code on a platform comprising said destination processor. According to the invention, the simulation is performed on a native platform having a processor different from the destination processor comprising the aforementioned data cache memory to be modelled, said modelling being performed by means of the...

  2. Test data generation for LRU cache-memory testing

    OpenAIRE

    Evgeni, Kornikhin

    2009-01-01

    System functional testing of microprocessors deals with many assembly programs of given behavior. The paper proposes new constraint-based algorithm of initial cache-memory contents generation for given behavior of assembly program (with cache misses and hits). Although algorithm works for any types of cache-memory, the paper describes algorithm in detail for basis types of cache-memory only: fully associative cache and direct mapped cache.

  3. Web Caching

    Indian Academy of Sciences (India)

    leveraged through Web caching technology. Specifically, Web caching becomes an ... Web routing can improve the overall performance of the Internet. Web caching is similar to memory system caching - a Web cache stores Web resources in ...

  4. Alignment of Memory Transfers of a Time-Predictable Stack Cache

    DEFF Research Database (Denmark)

    Abbaspourseyedi, Sahar; Brandner, Florian

    2014-01-01

    of complex cache states. Instead, only the occupancy level of the cache has to be determined. The memory transfers generated by the standard stack cache are not generally aligned. These unaligned accesses risk to introduce complexity to the otherwise simple WCET analysis. In this work, we investigate three...

  5. Optical RAM-enabled cache memory and optical routing for chip multiprocessors: technologies and architectures

    Science.gov (United States)

    Pleros, Nikos; Maniotis, Pavlos; Alexoudi, Theonitsa; Fitsios, Dimitris; Vagionas, Christos; Papaioannou, Sotiris; Vyrsokinos, K.; Kanellos, George T.

    2014-03-01

    The processor-memory performance gap, commonly referred to as "Memory Wall" problem, owes to the speed mismatch between processor and electronic RAM clock frequencies, forcing current Chip Multiprocessor (CMP) configurations to consume more than 50% of the chip real-estate for caching purposes. In this article, we present our recent work spanning from Si-based integrated optical RAM cell architectures up to complete optical cache memory architectures for Chip Multiprocessor configurations. Moreover, we discuss on e/o router subsystems with up to Tb/s routing capacity for cache interconnection purposes within CMP configurations, currently pursued within the FP7 PhoxTrot project.

  6. Adaptive Neuro-fuzzy Inference System as Cache Memory Replacement Policy

    Directory of Open Access Journals (Sweden)

    CHUNG, Y. M.

    2014-02-01

    Full Text Available To date, no cache memory replacement policy that can perform efficiently for all types of workloads is yet available. Replacement policies used in level 1 cache memory may not be suitable in level 2. In this study, we focused on developing an adaptive neuro-fuzzy inference system (ANFIS as a replacement policy for improving level 2 cache performance in terms of miss ratio. The recency and frequency of referenced blocks were used as input data for ANFIS to make decisions on replacement. MATLAB was employed as a training tool to obtain the trained ANFIS model. The trained ANFIS model was implemented on SimpleScalar. Simulations on SimpleScalar showed that the miss ratio improved by as high as 99.95419% and 99.95419% for instruction level 2 cache, and up to 98.04699% and 98.03467% for data level 2 cache compared with least recently used and least frequently used, respectively.

  7. Do Clark's nutcrackers demonstrate what-where-when memory on a cache-recovery task?

    Science.gov (United States)

    Gould, Kristy L; Ort, Amy J; Kamil, Alan C

    2012-01-01

    What-where-when (WWW) memory during cache recovery was investigated in six Clark's nutcrackers. During caching, both red- and blue-colored pine seeds were cached by the birds in holes filled with sand. Either a short (3 day) retention interval (RI) or a long (9 day) RI was followed by a recovery session during which caches were replaced with either a single seed or wooden bead depending upon the color of the cache and length of the retention interval. Knowledge of what was in the cache (seed or bead), where it was located, and when the cache had been made (3 or 9 days ago) were the three WWW memory components under investigation. Birds recovered items (bead or seed) at above chance levels, demonstrating accurate spatial memory. They also recovered seeds more than beads after the long RI, but not after the short RI, when they recovered seeds and beads equally often. The differential recovery after the long RI demonstrates that nutcrackers may have the capacity for WWW memory during this task, but it is not clear why it was influenced by RI duration.

  8. Recalling Arabic and English Prefixed and Suffixed Verbs among Arabic-English Bilingual Speakers: An Experimental Study in Relation to Working Memory

    Directory of Open Access Journals (Sweden)

    Jiyar Othman

    2016-01-01

    Full Text Available The current study focuses on how prefixes and suffixes in Arabic and English impact one’s working memory capacity to recall verbs.  Further, it deals with whether or not Arabic-English bilingual speakers recall Arabic and English prefixed and suffixed verbs differently. To investigate this, the study was conducted in the form of two experiments on a group of 10 graduate students. The first experiment was on Arabic prefixed and suffixed verbs, whereas the second experiment was conducted similarly on English. The study concluded that suffixed Arabic verbs were recalled more than the prefixed ones, whereas in English the result was contrary where the participants could recall prefixed verbs more than the suffixed ones. This shows that L2 (Second Language does not differ from L1 (First Language in the effort exerted to recall words. Rather, the findings may suggest that it is easier to recall words in the second language, which might be due to the intensive instruction received in the second language. The study also discovered that several other factors played important roles in making the participants recall the items such as word-length effect, frequency and recency of the words.

  9. Cache and memory hierarchy design a performance directed approach

    CERN Document Server

    Przybylski, Steven A

    1991-01-01

    An authoritative book for hardware and software designers. Caches are by far the simplest and most effective mechanism for improving computer performance. This innovative book exposes the characteristics of performance-optimal single and multi-level cache hierarchies by approaching the cache design process through the novel perspective of minimizing execution times. It presents useful data on the relative performance of a wide spectrum of machines and offers empirical and analytical evaluations of the underlying phenomena. This book will help computer professionals appreciate the impact of ca

  10. The Optimization of In-Memory Space Partitioning Trees for Cache Utilization

    Science.gov (United States)

    Yeo, Myung Ho; Min, Young Soo; Bok, Kyoung Soo; Yoo, Jae Soo

    In this paper, a novel cache conscious indexing technique based on space partitioning trees is proposed. Many researchers investigated efficient cache conscious indexing techniques which improve retrieval performance of in-memory database management system recently. However, most studies considered data partitioning and targeted fast information retrieval. Existing data partitioning-based index structures significantly degrade performance due to the redundant accesses of overlapped spaces. Specially, R-tree-based index structures suffer from the propagation of MBR (Minimum Bounding Rectangle) information by updating data frequently. In this paper, we propose an in-memory space partitioning index structure for optimal cache utilization. The proposed index structure is compared with the existing index structures in terms of update performance, insertion performance and cache-utilization rate in a variety of environments. The results demonstrate that the proposed index structure offers better performance than existing index structures.

  11. Sex, estradiol, and spatial memory in a food-caching corvid.

    Science.gov (United States)

    Rensel, Michelle A; Ellis, Jesse M S; Harvey, Brigit; Schlinger, Barney A

    2015-09-01

    Estrogens significantly impact spatial memory function in mammalian species. Songbirds express the estrogen synthetic enzyme aromatase at relatively high levels in the hippocampus and there is evidence from zebra finches that estrogens facilitate performance on spatial learning and/or memory tasks. It is unknown, however, whether estrogens influence hippocampal function in songbirds that naturally exhibit memory-intensive behaviors, such as cache recovery observed in many corvid species. To address this question, we examined the impact of estradiol on spatial memory in non-breeding Western scrub-jays, a species that routinely participates in food caching and retrieval in nature and in captivity. We also asked if there were sex differences in performance or responses to estradiol. Utilizing a combination of an aromatase inhibitor, fadrozole, with estradiol implants, we found that while overall cache recovery rates were unaffected by estradiol, several other indices of spatial memory, including searching efficiency and efficiency to retrieve the first item, were impaired in the presence of estradiol. In addition, males and females differed in some performance measures, although these differences appeared to be a consequence of the nature of the task as neither sex consistently out-performed the other. Overall, our data suggest that a sustained estradiol elevation in a food-caching bird impairs some, but not all, aspects of spatial memory on an innate behavioral task, at times in a sex-specific manner. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Fundamental Parallel Algorithms for Private-Cache Chip Multiprocessors

    DEFF Research Database (Denmark)

    Arge, Lars Allan; Goodrich, Michael T.; Nelson, Michael

    2008-01-01

    about the way cores are interconnected, for we assume that all inter-processor communication occurs through the memory hierarchy. We study several fundamental problems, including prefix sums, selection, and sorting, which often form the building blocks of other parallel algorithms. Indeed, we present...... two sorting algorithms, a distribution sort and a mergesort. Our algorithms are asymptotically optimal in terms of parallel cache accesses and space complexity under reasonable assumptions about the relationships between the number of processors, the size of memory, and the size of cache blocks....... In addition, we study sorting lower bounds in a computational model, which we call the parallel external-memory (PEM) model, that formalizes the essential properties of our algorithms for private-cache CMPs....

  13. Analytical derivation of traffic patterns in cache-coherent shared-memory systems

    DEFF Research Database (Denmark)

    Stuart, Matthias Bo; Sparsø, Jens

    2011-01-01

    This paper presents an analytical method to derive the worst-case traffic pattern caused by a task graph mapped to a cache-coherent shared-memory system. Our analysis allows designers to rapidly evaluate the impact of different mappings of tasks to IP cores on the traffic pattern. The accuracy...

  14. A Unified Buffering Management with Set Divisible Cache for PCM Main Memory

    Institute of Scientific and Technical Information of China (English)

    Mei-Ying Bian; Su-Kyung Yoon; Jeong-Geun Kim; Sangjae Nam; Shin-Dug Kim

    2016-01-01

    This research proposes a phase-change memory (PCM) based main memory system with an effective combi-nation of a superblock-based adaptive buffering structure and its associated set divisible last-level cache (LLC). To achieve high performance similar to that of dynamic random-access memory (DRAM) based main memory, the superblock-based adaptive buffer (SABU) is comprised of dual DRAM buffers, i.e., an aggressive superblock-based pre-fetching buffer (SBPB) and an adaptive sub-block reusing buffer (SBRB), and a set divisible LLC based on a cache space optimization scheme. According to our experiment, the longer PCM access latency can typically be hidden using our proposed SABU, which can significantly reduce the number of writes over the PCM main memory by 26.44%. The SABU approach can reduce PCM access latency up to 0.43 times, compared with conventional DRAM main memory. Meanwhile, the average memory energy consumption can be reduced by 19.7%.

  15. CPU and cache efficient management of memory-resident databases

    NARCIS (Netherlands)

    Pirk, H.; Funke, F.; Grund, M.; Neumann, T.; Leser, U.; Manegold, S.; Kemper, A.; Kersten, M.L.

    2013-01-01

    Memory-Resident Database Management Systems (MRDBMS) have to be optimized for two resources: CPU cycles and memory bandwidth. To optimize for bandwidth in mixed OLTP/OLAP scenarios, the hybrid or Partially Decomposed Storage Model (PDSM) has been proposed. However, in current implementations,

  16. CPU and Cache Efficient Management of Memory-Resident Databases

    NARCIS (Netherlands)

    H. Pirk (Holger); F. Funke; M. Grund; T. Neumann (Thomas); U. Leser; S. Manegold (Stefan); A. Kemper (Alfons); M.L. Kersten (Martin)

    2013-01-01

    htmlabstractMemory-Resident Database Management Systems (MRDBMS) have to be optimized for two resources: CPU cycles and memory bandwidth. To optimize for bandwidth in mixed OLTP/OLAP scenarios, the hybrid or Partially Decomposed Storage Model (PDSM) has been proposed. However, in current

  17. Data cache organization for accurate timing analysis

    DEFF Research Database (Denmark)

    Schoeberl, Martin; Huber, Benedikt; Puffitsch, Wolfgang

    2013-01-01

    it is important to classify memory accesses as either cache hit or cache miss. The addresses of instruction fetches are known statically and static cache hit/miss classification is possible for the instruction cache. The access to data that is cached in the data cache is harder to predict statically. Several...

  18. Cache Conscious Data Layouting for In-Memory Databases

    NARCIS (Netherlands)

    H. Pirk (Holger)

    2010-01-01

    htmlabstractMany applications with manually implemented data management exhibit a data storage pattern in which semantically related data items are stored closer in memory than unrelated data items. The strong sematic relationship between these data items commonly induces contemporary accesses to

  19. MESI Cache Coherence Simulator for Teaching Purposes

    OpenAIRE

    Gómez Luna, Juan; Herruzo Gómez, Ezequiel; Benavides Benítez, José Ignacio

    2009-01-01

    Nowadays, the computational systems (multi and uniprocessors) need to avoid the cache coherence problem. There are some techniques to solve this problem. The MESI cache coherence protocol is one of them. This paper presents a simulator of the MESI protocol which is used for teaching the cache memory coherence on the computer systems with hierarchical memory system and for explaining the process of the cache memory location in multilevel cache memory systems. The paper shows a d...

  20. Modified stretched exponential model of computer system resources management limitations-The case of cache memory

    Science.gov (United States)

    Strzałka, Dominik; Dymora, Paweł; Mazurek, Mirosław

    2018-02-01

    In this paper we present some preliminary results in the field of computer systems management with relation to Tsallis thermostatistics and the ubiquitous problem of hardware limited resources. In the case of systems with non-deterministic behaviour, management of their resources is a key point that guarantees theirs acceptable performance and proper working. This is very wide problem that stands for many challenges in financial, transport, water and food, health, etc. areas. We focus on computer systems with attention paid to cache memory and propose to use an analytical model that is able to connect non-extensive entropy formalism, long-range dependencies, management of system resources and queuing theory. Obtained analytical results are related to the practical experiment showing interesting and valuable results.

  1. Unfavorable Strides in Cache Memory Systems (RNR Technical Report RNR-92-015

    Directory of Open Access Journals (Sweden)

    David H. Bailey

    1995-01-01

    Full Text Available An important issue in obtaining high performance on a scientific application running on a cache-based computer system is the behavior of the cache when data are accessed at a constant stride. Others who have discussed this issue have noted an odd phenomenon in such situations: A few particular innocent-looking strides result in sharply reduced cache efficiency. In this article, this problem is analyzed, and a simple formula is presented that accurately gives the cache efficiency for various cache parameters and data strides.

  2. Potential Mechanisms Driving Population Variation in Spatial Memory and the Hippocampus in Food-caching Chickadees.

    Science.gov (United States)

    Croston, Rebecca; Branch, Carrie L; Kozlovsky, Dovid Y; Roth, Timothy C; LaDage, Lara D; Freas, Cody A; Pravosudov, Vladimir V

    2015-09-01

    Harsh environments and severe winters have been hypothesized to favor improvement of the cognitive abilities necessary for successful foraging. Geographic variation in winter climate, then, is likely associated with differences in selection pressures on cognitive ability, which could lead to evolutionary changes in cognition and its neural mechanisms, assuming that variation in these traits is heritable. Here, we focus on two species of food-caching chickadees (genus Poecile), which rely on stored food for survival over winter and require the use of spatial memory to recover their stores. These species also exhibit extensive climate-related population level variation in spatial memory and the hippocampus, including volume, the total number and size of neurons, and adults' rates of neurogenesis. Such variation could be driven by several mechanisms within the context of natural selection, including independent, population-specific selection (local adaptation), environment experience-based plasticity, developmental differences, and/or epigenetic differences. Extensive data on cognition, brain morphology, and behavior in multiple populations of these two species of chickadees along longitudinal, latitudinal, and elevational gradients in winter climate are most consistent with the hypothesis that natural selection drives the evolution of local adaptations associated with spatial memory differences among populations. Conversely, there is little support for the hypotheses that environment-induced plasticity or developmental differences are the main causes of population differences across climatic gradients. Available data on epigenetic modifications of memory ability are also inconsistent with the observed patterns of population variation, with birds living in more stressful and harsher environments having better spatial memory associated with a larger hippocampus and a larger number of hippocampal neurons. Overall, the existing data are most consistent with the

  3. A Cross-Layer Framework for Designing and Optimizing Deeply-Scaled FinFET-Based Cache Memories

    Directory of Open Access Journals (Sweden)

    Alireza Shafaei

    2015-08-01

    Full Text Available This paper presents a cross-layer framework in order to design and optimize energy-efficient cache memories made of deeply-scaled FinFET devices. The proposed design framework spans device, circuit and architecture levels and considers both super- and near-threshold modes of operation. Initially, at the device-level, seven FinFET devices on a 7-nm process technology are designed in which only one geometry-related parameter (e.g., fin width, gate length, gate underlap is changed per device. Next, at the circuit-level, standard 6T and 8T SRAM cells made of these 7-nm FinFET devices are characterized and compared in terms of static noise margin, access latency, leakage power consumption, etc. Finally, cache memories with all different combinations of devices and SRAM cells are evaluated at the architecture-level using a modified version of the CACTI tool with FinFET support and other considerations for deeply-scaled technologies. Using this design framework, it is observed that L1 cache memory made of longer channel FinFET devices operating at the near-threshold regime achieves the minimum energy operation point.

  4. Recognizing Prefixes in Scientific Quantities

    Science.gov (United States)

    Sokolowski, Andrzej

    2015-01-01

    Although recognizing prefixes in physical quantities is inherent for practitioners, it might not be inherent for students, who do not use prefixes in their everyday life experiences. This deficiency surfaces in AP Physics exams. For example, readers of an AP Physics exam reported "a common mistake of incorrectly converting nanometers to…

  5. Proposal and development of a reconfigurable associativity algorithm in cache memories.

    OpenAIRE

    Roberto Borges Kerr Junior

    2008-01-01

    A evolução constante dos processadores está aumentando cada vez o overhead dos acessos à memória. Tentando evitar este problema, os desenvolvedores de processadores utilizam diversas técnicas, entre elas, o emprego de memórias cache na hierarquia de memórias dos computadores. As memórias cache, por outro lado, não conseguem suprir totalmente as suas necessidades, sendo interessante alguma técnica que tornasse possível aproveitar melhor a memória cache. Para resolver este problema, autores pro...

  6. Efficiently GPU-accelerating long kernel convolutions in 3-D DIRECT TOF PET reconstruction via memory cache optimization

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Sungsoo; Mueller, Klaus [Stony Brook Univ., NY (United States). Center for Visual Computing; Matej, Samuel [Pennsylvania Univ., Philadelphia, PA (United States). Dept. of Radiology

    2011-07-01

    The DIRECT represents a novel approach for 3-D Time-of-Flight (TOF) PET reconstruction. Its novelty stems from the fact that it performs all iterative predictor-corrector operations directly in image space. The projection operations now amount to convolutions in image space, using long TOF (resolution) kernels. While for spatially invariant kernels the computational complexity can be algorithmically overcome by replacing spatial convolution with multiplication in Fourier space, spatially variant kernels cannot use this shortcut. Therefore in this paper, we describe a GPU-accelerated approach for this task. However, the intricate parallel architecture of GPUs poses its own challenges, and careful memory and thread management is the key to obtaining optimal results. As convolution is mainly memory-bound we focus on the former, proposing two types of memory caching schemes that warrant best cache memory re-use by the parallel threads. In contrast to our previous two-stage algorithm, the schemes presented here are both single-stage which is more accurate. (orig.)

  7. Software trace cache

    OpenAIRE

    Ramírez Bellido, Alejandro; Larriba Pey, Josep; Valero Cortés, Mateo

    2005-01-01

    We explore the use of compiler optimizations, which optimize the layout of instructions in memory. The target is to enable the code to make better use of the underlying hardware resources regardless of the specific details of the processor/architecture in order to increase fetch performance. The Software Trace Cache (STC) is a code layout algorithm with a broader target than previous layout optimizations. We target not only an improvement in the instruction cache hit rate, but also an increas...

  8. Memory for multiple cache locations and prey quantities in a food-hoarding songbird

    Directory of Open Access Journals (Sweden)

    Nicola eArmstrong

    2012-12-01

    Full Text Available Most animals can discriminate between pairs of numbers that are each less than four without training. However, North Island robins (Petroica longipes, a food hoarding songbird endemic to New Zealand, can discriminate between quantities of items as high as eight without training. Here we investigate whether robins are capable of other complex quantity discrimination tasks. We test whether their ability to discriminate between small quantities declines with 1. the number of cache sites containing prey rewards and 2. the length of time separating cache creation and retrieval (retention interval. Results showed that subjects generally performed above chance expectations. They were equally able to discriminate between different combinations of prey quantities that were hidden from view in 2, 3 and 4 cache sites from between 1, 10 and 60 seconds. Overall results indicate that North Island robins can process complex quantity information involving more than two discrete quantities of items for up to one minute long retention intervals without training.

  9. An ESL Approach for Energy Consumption Analysis of Cache Memories in SoC Platforms

    Directory of Open Access Journals (Sweden)

    Abel G. Silva-Filho

    2011-01-01

    Full Text Available The design of complex circuits as SoCs presents two great challenges to designers. One is the speeding up of system functionality modeling and the second is the implementation of the system in an architecture that meets performance and power consumption requirements. Thus, developing new high-level specification mechanisms for the reduction of the design effort with automatic architecture exploration is a necessity. This paper proposes an Electronic-System-Level (ESL approach for system modeling and cache energy consumption analysis of SoCs called PCacheEnergyAnalyzer. It uses as entry a high-level UML-2.0 profile model of the system and it generates a simulation model of a multicore platform that can be analyzed for cache tuning. PCacheEnergyAnalyzer performs static/dynamic energy consumption analysis of caches on platforms that may have different processors. Architecture exploration is achieved by letting designers choose different processors for platform generation and different mechanisms for cache optimization. PCacheEnergyAnalyzer has been validated with several applications of Mibench, Mediabench, and PowerStone benchmarks, and results show that it provides analysis with reduced simulation effort.

  10. Population genetic structure and its implications for adaptive variation in memory and the hippocampus on a continental scale in food-caching black-capped chickadees.

    Science.gov (United States)

    Pravosudov, V V; Roth, T C; Forister, M L; Ladage, L D; Burg, T M; Braun, M J; Davidson, B S

    2012-09-01

    Food-caching birds rely on stored food to survive the winter, and spatial memory has been shown to be critical in successful cache recovery. Both spatial memory and the hippocampus, an area of the brain involved in spatial memory, exhibit significant geographic variation linked to climate-based environmental harshness and the potential reliance on food caches for survival. Such geographic variation has been suggested to have a heritable basis associated with differential selection. Here, we ask whether population genetic differentiation and potential isolation among multiple populations of food-caching black-capped chickadees is associated with differences in memory and hippocampal morphology by exploring population genetic structure within and among groups of populations that are divergent to different degrees in hippocampal morphology. Using mitochondrial DNA and 583 AFLP loci, we found that population divergence in hippocampal morphology is not significantly associated with neutral genetic divergence or geographic distance, but instead is significantly associated with differences in winter climate. These results are consistent with variation in a history of natural selection on memory and hippocampal morphology that creates and maintains differences in these traits regardless of population genetic structure and likely associated gene flow. Published 2012. This article is a US Government work and is in the public domain in the USA.

  11. A Parallel Prefix Algorithm for Almost Toeplitz Tridiagonal Systems

    Science.gov (United States)

    Sun, Xian-He; Joslin, Ronald D.

    1995-01-01

    A compact scheme is a discretization scheme that is advantageous in obtaining highly accurate solutions. However, the resulting systems from compact schemes are tridiagonal systems that are difficult to solve efficiently on parallel computers. Considering the almost symmetric Toeplitz structure, a parallel algorithm, simple parallel prefix (SPP), is proposed. The SPP algorithm requires less memory than the conventional LU decomposition and is efficient on parallel machines. It consists of a prefix communication pattern and AXPY operations. Both the computation and the communication can be truncated without degrading the accuracy when the system is diagonally dominant. A formal accuracy study has been conducted to provide a simple truncation formula. Experimental results have been measured on a MasPar MP-1 SIMD machine and on a Cray 2 vector machine. Experimental results show that the simple parallel prefix algorithm is a good algorithm for symmetric, almost symmetric Toeplitz tridiagonal systems and for the compact scheme on high-performance computers.

  12. Reducing Competitive Cache Misses in Modern Processor Architectures

    OpenAIRE

    Prisagjanec, Milcho; Mitrevski, Pece

    2017-01-01

    The increasing number of threads inside the cores of a multicore processor, and competitive access to the shared cache memory, become the main reasons for an increased number of competitive cache misses and performance decline. Inevitably, the development of modern processor architectures leads to an increased number of cache misses. In this paper, we make an attempt to implement a technique for decreasing the number of competitive cache misses in the first level of cache memory. This tec...

  13. Cache-Oblivious Algorithms and Data Structures

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting

    2004-01-01

    Frigo, Leiserson, Prokop and Ramachandran in 1999 introduced the ideal-cache model as a formal model of computation for developing algorithms in environments with multiple levels of caching, and coined the terminology of cache-oblivious algorithms. Cache-oblivious algorithms are described...... as standard RAM algorithms with only one memory level, i.e. without any knowledge about memory hierarchies, but are analyzed in the two-level I/O model of Aggarwal and Vitter for an arbitrary memory and block size and an optimal off-line cache replacement strategy. The result are algorithms that automatically...... apply to multi-level memory hierarchies. This paper gives an overview of the results achieved on cache-oblivious algorithms and data structures since the seminal paper by Frigo et al....

  14. Funnel Heap - A Cache Oblivious Priority Queue

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Fagerberg, Rolf

    2002-01-01

    The cache oblivious model of computation is a two-level memory model with the assumption that the parameters of the model are unknown to the algorithms. A consequence of this assumption is that an algorithm efficient in the cache oblivious model is automatically efficient in a multi-level memory...

  15. Verbal prefixation, construction grammar, and semantic compatibility

    DEFF Research Database (Denmark)

    Lewandowski, Wojciech

    2016-01-01

    This paper aims to analyze the interaction between prefixes, verbs, and abstract argument structure constructions, using as a testing ground the locative alternation. It has been assumed that in order to participate in the locative alternation, a verb must specify a manner of motion from which a ...... between resultative prefixes, alternating verbs, and the more abstract change-of-state variant is driven by semantic coherence. Keywords: resultative prefixes, construction grammar, semantic coherence, locative alternation, Polish...

  16. A detailed GPU cache model based on reuse distance theory

    NARCIS (Netherlands)

    Nugteren, C.; Braak, van den G.J.W.; Corporaal, H.; Bal, H.E.

    2014-01-01

    As modern GPUs rely partly on their on-chip memories to counter the imminent off-chip memory wall, the efficient use of their caches has become important for performance and energy. However, optimising cache locality systematically requires insight into and prediction of cache behaviour. On

  17. Architectural Development and Performance Analysis of a Primary Data Cache with Read Miss Address Prediction Capability

    National Research Council Canada - National Science Library

    Christensen, Kathryn

    1998-01-01

    .... The Predictive Read Cache (PRC) further improves the overall memory hierarchy performance by tracking the data read miss patterns of memory accesses, developing a prediction for the next access and prefetching the data into the faster cache memory...

  18. Medical Terminology: Prefixes. Health Occupations Education Module.

    Science.gov (United States)

    Temple Univ., Philadelphia, PA. Div. of Vocational Education.

    This module on medical terminology (prefixes) is one of 17 modules designed for individualized instruction in health occupations education programs at both the secondary and postsecondary levels. This module consists of an introduction to prefixes, a list of resources needed, and three learning experiences. Each learning experience contains an…

  19. Prefix reversals on binary and ternary strings

    NARCIS (Netherlands)

    Hurkens, C.A.J.; van Iersel, L.J.J.; Keijsper, J.C.M.; Kelk, S.M.; Stougie, L.; Tromp, J.T.

    2007-01-01

    Given a permutation $\\pi$, the application of prefix reversal $f^{(i)}$ to $\\pi$ reverses the order of the first $i$ elements of $\\pi$. The problem of sorting by prefix reversals (also known as pancake flipping), made famous by Gates and Papadimitriou (Discrete Math., 27 (1979), pp. 47–57), asks

  20. Prefix reversals on binary and ternary strings

    NARCIS (Netherlands)

    Hurkens, C.A.J.; Iersel, van L.J.J.; Keijsper, J.C.M.; Kelk, S.M.; Stougie, L.; Tromp, J.T.

    2007-01-01

    Given a permutation $\\pi$, the application of prefix reversal $f^{(i)}$ to $\\pi$ reverses the order of the first $i$ elements of $\\pi$. The problem of sorting by prefix reversals (also known as pancake flipping), made famous by Gates and Papadimitriou (Discrete Math., 27 (1979), pp. 47–57), asks for

  1. Comparison between BIDE, PrefixSpan, and TRuleGrowth for Mining of Indonesian Text

    Science.gov (United States)

    Sa'adillah Maylawati, Dian; Irfan, Mohamad; Budiawan Zulfikar, Wildan

    2017-01-01

    Mining proscess for Indonesian language still be an interesting research. Multiple of words representation was claimed can keep the meaning of text better than bag of words. In this paper, we compare several sequential pattern algortihm, among others BIDE (BIDirectional Extention), PrefixSpan, and TRuleGrowth. All of those algorithm produce frequent word sequence to keep the meaning of text. However, the experiment result, with 14.006 of Indonesian tweet from Twitter, shows that BIDE can produce more efficient frequent word sequence than PrefixSpan and TRuleGrowth without missing the meaning of text. Then, the average of time process of PrefixSpan is faster than BIDE and TRuleGrowth. In the other hand, PrefixSpan and TRuleGrowth is more efficient in using memory than BIDE.

  2. Efficient sorting using registers and caches

    DEFF Research Database (Denmark)

    Wickremesinghe, Rajiv; Arge, Lars Allan; Chase, Jeffrey S.

    2002-01-01

    . Inadequate models lead to poor algorithmic choices and an incomplete understanding of algorithm behavior on real machines.A key step toward developing better models is to quantify the performance effects of features not reflected in the models. This paper explores the effect of memory system features...... on sorting performance. We introduce a new cache-conscious sorting algorithm, R-MERGE, which achieves better performance in practice over algorithms that are superior in the theoretical models. R-MERGE is designed to minimize memory stall cycles rather than cache misses by considering features common to many......Modern computer systems have increasingly complex memory systems. Common machine models for algorithm analysis do not reflect many of the features of these systems, e.g., large register sets, lockup-free caches, cache hierarchies, associativity, cache line fetching, and streaming behavior...

  3. Search-Order Independent State Caching

    DEFF Research Database (Denmark)

    Evangelista, Sami; Kristensen, Lars Michael

    2010-01-01

    State caching is a memory reduction technique used by model checkers to alleviate the state explosion problem. It has traditionally been coupled with a depth-first search to ensure termination.We propose and experimentally evaluate an extension of the state caching method for general state...

  4. Store operations to maintain cache coherence

    Energy Technology Data Exchange (ETDEWEB)

    Evangelinos, Constantinos; Nair, Ravi; Ohmacht, Martin

    2017-08-01

    In one embodiment, a computer-implemented method includes encountering a store operation during a compile-time of a program, where the store operation is applicable to a memory line. It is determined, by a computer processor, that no cache coherence action is necessary for the store operation. A store-without-coherence-action instruction is generated for the store operation, responsive to determining that no cache coherence action is necessary. The store-without-coherence-action instruction specifies that the store operation is to be performed without a cache coherence action, and cache coherence is maintained upon execution of the store-without-coherence-action instruction.

  5. Store operations to maintain cache coherence

    Energy Technology Data Exchange (ETDEWEB)

    Evangelinos, Constantinos; Nair, Ravi; Ohmacht, Martin

    2017-09-12

    In one embodiment, a computer-implemented method includes encountering a store operation during a compile-time of a program, where the store operation is applicable to a memory line. It is determined, by a computer processor, that no cache coherence action is necessary for the store operation. A store-without-coherence-action instruction is generated for the store operation, responsive to determining that no cache coherence action is necessary. The store-without-coherence-action instruction specifies that the store operation is to be performed without a cache coherence action, and cache coherence is maintained upon execution of the store-without-coherence-action instruction.

  6. The Cost of Cache-Oblivious Searching

    DEFF Research Database (Denmark)

    Bender, Michael A.; Brodal, Gert Stølting; Fagerberg, Rolf

    2003-01-01

    , multilevel memory hierarchies can be modelled. It is shown that as k grows, the search costs of the optimal k-level DAM search structure and of the optimal cache-oblivious search structure rapidly converge. This demonstrates that for a multilevel memory hierarchy, a simple cache-oblivious structure almost......Tight bounds on the cost of cache-oblivious searching are proved. It is shown that no cache-oblivious search structure can guarantee that a search performs fewer than lg e log B N block transfers between any two levels of the memory hierarchy. This lower bound holds even if all of the block sizes...... the random placement of the rst element of the structure in memory. As searching in the Disk Access Model (DAM) can be performed in log B N + 1 block transfers, this result shows a separation between the 2-level DAM and cacheoblivious memory-hierarchy models. By extending the DAM model to k levels...

  7. Don't make cache too complex: A simple probability-based cache management scheme for SSDs.

    Directory of Open Access Journals (Sweden)

    Seungjae Baek

    Full Text Available Solid-state drives (SSDs have recently become a common storage component in computer systems, and they are fueled by continued bit cost reductions achieved with smaller feature sizes and multiple-level cell technologies. However, as the flash memory stores more bits per cell, the performance and reliability of the flash memory degrade substantially. To solve this problem, a fast non-volatile memory (NVM-based cache has been employed within SSDs to reduce the long latency required to write data. Absorbing small writes in a fast NVM cache can also reduce the number of flash memory erase operations. To maximize the benefits of an NVM cache, it is important to increase the NVM cache utilization. In this paper, we propose and study ProCache, a simple NVM cache management scheme, that makes cache-entrance decisions based on random probability testing. Our scheme is motivated by the observation that frequently written hot data will eventually enter the cache with a high probability, and that infrequently accessed cold data will not enter the cache easily. Owing to its simplicity, ProCache is easy to implement at a substantially smaller cost than similar previously studied techniques. We evaluate ProCache and conclude that it achieves comparable performance compared to a more complex reference counter-based cache-management scheme.

  8. Static analysis of worst-case stack cache behavior

    DEFF Research Database (Denmark)

    Jordan, Alexander; Brandner, Florian; Schoeberl, Martin

    2013-01-01

    Utilizing a stack cache in a real-time system can aid predictability by avoiding interference that heap memory traffic causes on the data cache. While loads and stores are guaranteed cache hits, explicit operations are responsible for managing the stack cache. The behavior of these operations can......-graph, the worst-case bounds can be efficiently yet precisely determined. Our evaluation using the MiBench benchmark suite shows that only 37% and 21% of potential stack cache operations actually store to and load from memory, respectively. Analysis times are modest, on average running between 0.46s and 1.30s per...

  9. Caching Patterns and Implementation

    Directory of Open Access Journals (Sweden)

    Octavian Paul ROTARU

    2006-01-01

    Full Text Available Repetitious access to remote resources, usually data, constitutes a bottleneck for many software systems. Caching is a technique that can drastically improve the performance of any database application, by avoiding multiple read operations for the same data. This paper addresses the caching problems from a pattern perspective. Both Caching and caching strategies, like primed and on demand, are presented as patterns and a pattern-based flexible caching implementation is proposed.The Caching pattern provides method of expensive resources reacquisition circumvention. Primed Cache pattern is applied in situations in which the set of required resources, or at least a part of it, can be predicted, while Demand Cache pattern is applied whenever the resources set required cannot be predicted or is unfeasible to be buffered.The advantages and disadvantages of all the caching patterns presented are also discussed, and the lessons learned are applied in the implementation of the pattern-based flexible caching solution proposed.

  10. Cache-Oblivious Mesh Layouts

    International Nuclear Information System (INIS)

    Yoon, S; Lindstrom, P; Pascucci, V; Manocha, D

    2005-01-01

    We present a novel method for computing cache-oblivious layouts of large meshes that improve the performance of interactive visualization and geometric processing algorithms. Given that the mesh is accessed in a reasonably coherent manner, we assume no particular data access patterns or cache parameters of the memory hierarchy involved in the computation. Furthermore, our formulation extends directly to computing layouts of multi-resolution and bounding volume hierarchies of large meshes. We develop a simple and practical cache-oblivious metric for estimating cache misses. Computing a coherent mesh layout is reduced to a combinatorial optimization problem. We designed and implemented an out-of-core multilevel minimization algorithm and tested its performance on unstructured meshes composed of tens to hundreds of millions of triangles. Our layouts can significantly reduce the number of cache misses. We have observed 2-20 times speedups in view-dependent rendering, collision detection, and isocontour extraction without any modification of the algorithms or runtime applications

  11. Cache-Conscious Radix-Decluster Projections

    NARCIS (Netherlands)

    S. Manegold (Stefan); P.A. Boncz (Peter); N.J. Nes (Niels); M.L. Kersten (Martin)

    2004-01-01

    textabstractAs CPUs become more powerful with Moore's law and memory latencies stay constant, the impact of the memory access performance bottleneck continues to grow on relational operators like join, which can exhibit random access on a memory region larger than the hardware caches. While

  12. Evidence for cache surveillance by a scatter-hoarding rodent

    NARCIS (Netherlands)

    Hirsch, B.T.; Kays, R.; Jansen, P.A.

    2013-01-01

    The mechanisms by which food-hoarding animals are capable of remembering the locations of numerous cached food items over long time spans has been the focus of intensive research. The ‘memory enhancement hypothesis’ states that hoarders reinforce spatial memory of their caches by repeatedly

  13. Search-Order Independent State Caching

    DEFF Research Database (Denmark)

    Evangelista, Sami; Kristensen, Lars Michael

    2009-01-01

    State caching is a memory reduction technique used by model checkers to alleviate the state explosion problem. It has traditionally been coupled with a depth-first search to ensure termination.We propose and experimentally evaluate an extension of the state caching method for general state...... exploring algorithms that are independent of the search order (i.e., search algorithms that partition the state space into closed (visited) states, open (to visit) states and unmet states)....

  14. Sorting permutations by prefix and suffix rearrangements.

    Science.gov (United States)

    Lintzmayer, Carla Negri; Fertin, Guillaume; Dias, Zanoni

    2017-02-01

    Some interesting combinatorial problems have been motivated by genome rearrangements, which are mutations that affect large portions of a genome. When we represent genomes as permutations, the goal is to transform a given permutation into the identity permutation with the minimum number of rearrangements. When they affect segments from the beginning (respectively end) of the permutation, they are called prefix (respectively suffix) rearrangements. This paper presents results for rearrangement problems that involve prefix and suffix versions of reversals and transpositions considering unsigned and signed permutations. We give 2-approximation and ([Formula: see text])-approximation algorithms for these problems, where [Formula: see text] is a constant divided by the number of breakpoints (pairs of consecutive elements that should not be consecutive in the identity permutation) in the input permutation. We also give bounds for the diameters concerning these problems and provide ways of improving the practical results of our algorithms.

  15. An Adaptive Insertion and Promotion Policy for Partitioned Shared Caches

    Science.gov (United States)

    Mahrom, Norfadila; Liebelt, Michael; Raof, Rafikha Aliana A.; Daud, Shuhaizar; Hafizah Ghazali, Nur

    2018-03-01

    Cache replacement policies in chip multiprocessors (CMP) have been investigated extensively and proven able to enhance shared cache management. However, competition among multiple processors executing different threads that require simultaneous access to a shared memory may cause cache contention and memory coherence problems on the chip. These issues also exist due to some drawbacks of the commonly used Least Recently Used (LRU) policy employed in multiprocessor systems, which are because of the cache lines residing in the cache longer than required. In image processing analysis of for example extra pulmonary tuberculosis (TB), an accurate diagnosis for tissue specimen is required. Therefore, a fast and reliable shared memory management system to execute algorithms for processing vast amount of specimen image is needed. In this paper, the effects of the cache replacement policy in a partitioned shared cache are investigated. The goal is to quantify whether better performance can be achieved by using less complex replacement strategies. This paper proposes a Middle Insertion 2 Positions Promotion (MI2PP) policy to eliminate cache misses that could adversely affect the access patterns and the throughput of the processors in the system. The policy employs a static predefined insertion point, near distance promotion, and the concept of ownership in the eviction policy to effectively improve cache thrashing and to avoid resource stealing among the processors.

  16. Scope-Based Method Cache Analysis

    DEFF Research Database (Denmark)

    Huber, Benedikt; Hepp, Stefan; Schoeberl, Martin

    2014-01-01

    The quest for time-predictable systems has led to the exploration of new hardware architectures that simplify analysis and reasoning in the temporal domain, while still providing competitive performance. For the instruction memory, the method cache is a conceptually attractive solution, as it req......The quest for time-predictable systems has led to the exploration of new hardware architectures that simplify analysis and reasoning in the temporal domain, while still providing competitive performance. For the instruction memory, the method cache is a conceptually attractive solution...

  17. Unifying Prepositions and Prefixes in Russian: Conceptual structure versus syntax

    Directory of Open Access Journals (Sweden)

    Inna Tolskaya

    2007-12-01

    Full Text Available This paper is an attempt to unify the polysemous verbal prefixes and prepositions in Russian. At first glance, the variety of possible denotations of a given prefix might appear a chaotic set of idiomatic meanings, e.g., the prefix za- may refer to beginning of an action, movement to a position behind an object, a brief deviation from a path, completion of an action, while the corresponding preposition za can mean ‘behind,’ ‘after,’ ‘for,’ ‘in’ (like in ‘in an hour’, ‘at’ (like in ‘at the table’. I will propose a unified analysis, where the differences in meaning are claimed to arise from different syntactic positions, while the lexical entry of a prefix remains the same. The main focus is on the verbs of motion due to the consistent duality displayed by the prefix meanings when added to directional and non-directional motion verbs. It will turn out that many prefixes appear to modify path when added onto a directional motion verb and to refer to movement in time with non-directional motion verbs. This semantic distinction corresponds to distinct sets of syntactic properties, specific for each set of prefixes. These two classes of prefixes correspond to the lexical versus superlexical distinction. However, a tripartite division will emerge in each set, corresponding to source, path, and goal of motion (FROM, VIA and TO for lexical prefixes and to initiation, process and result for superlexical prefixes. This leads to the suggestion that the syntactic representation of a VP contains at least six distinct nodes for the Russian verbal prefixes, each characterized by predictable semantic and syntactic properties. The same prefix with a consistent meaning, shared with the corresponding preposition, will receive part of its denotation from the syntactic head it attaches to, thus allowing the polysemy to arise from position, rather than from arbitrary homophony. Thus, conceptual structure will be unified with syntax.

  18. Efficacy of Code Optimization on Cache-based Processors

    Science.gov (United States)

    VanderWijngaart, Rob F.; Chancellor, Marisa K. (Technical Monitor)

    1997-01-01

    The current common wisdom in the U.S. is that the powerful, cost-effective supercomputers of tomorrow will be based on commodity (RISC) micro-processors with cache memories. Already, most distributed systems in the world use such hardware as building blocks. This shift away from vector supercomputers and towards cache-based systems has brought about a change in programming paradigm, even when ignoring issues of parallelism. Vector machines require inner-loop independence and regular, non-pathological memory strides (usually this means: non-power-of-two strides) to allow efficient vectorization of array operations. Cache-based systems require spatial and temporal locality of data, so that data once read from main memory and stored in high-speed cache memory is used optimally before being written back to main memory. This means that the most cache-friendly array operations are those that feature zero or unit stride, so that each unit of data read from main memory (a cache line) contains information for the next iteration in the loop. Moreover, loops ought to be 'fat', meaning that as many operations as possible are performed on cache data-provided instruction caches do not overflow and enough registers are available. If unit stride is not possible, for example because of some data dependency, then care must be taken to avoid pathological strides, just ads on vector computers. For cache-based systems the issues are more complex, due to the effects of associativity and of non-unit block (cache line) size. But there is more to the story. Most modern micro-processors are superscalar, which means that they can issue several (arithmetic) instructions per clock cycle, provided that there are enough independent instructions in the loop body. This is another argument for providing fat loop bodies. With these restrictions, it appears fairly straightforward to produce code that will run efficiently on any cache-based system. It can be argued that although some of the important

  19. Hybrid caches: design and data management

    OpenAIRE

    Valero Bresó, Alejandro

    2013-01-01

    Cache memories have been usually implemented with Static Random-Access Memory (SRAM) technology since it is the fastest electronic memory technology. However, this technology consumes a high amount of leakage currents, which is a major design concern because leakage energy consumption increases as the transistor size shrinks. Alternative technologies are being considered to reduce this consumption. Among them, embedded Dynamic RAM (eDRAM) technology provides minimal area and le...

  20. Constraints on Negative Prefixation in Polish Sign Language.

    Science.gov (United States)

    Tomaszewski, Piotr

    2015-01-01

    The aim of this article is to describe a negative prefix, NEG-, in Polish Sign Language (PJM) which appears to be indigenous to the language. This is of interest given the relative rarity of prefixes in sign languages. Prefixed PJM signs were analyzed on the basis of both a corpus of texts signed by 15 deaf PJM users who are either native or near-native signers, and material including a specified range of prefixed signs as demonstrated by native signers in dictionary form (i.e. signs produced in isolation, not as part of phrases or sentences). In order to define the morphological rules behind prefixation on both the phonological and morphological levels, native PJM users were consulted for their expertise. The research results can enrich models for describing processes of grammaticalization in the context of the visual-gestural modality that forms the basis for sign language structure.

  1. Corvid re-caching without 'theory of mind': a model.

    Science.gov (United States)

    van der Vaart, Elske; Verbrugge, Rineke; Hemelrijk, Charlotte K

    2012-01-01

    Scrub jays are thought to use many tactics to protect their caches. For instance, they predominantly bury food far away from conspecifics, and if they must cache while being watched, they often re-cache their worms later, once they are in private. Two explanations have been offered for such observations, and they are intensely debated. First, the birds may reason about their competitors' mental states, with a 'theory of mind'; alternatively, they may apply behavioral rules learned in daily life. Although this second hypothesis is cognitively simpler, it does seem to require a different, ad-hoc behavioral rule for every caching and re-caching pattern exhibited by the birds. Our new theory avoids this drawback by explaining a large variety of patterns as side-effects of stress and the resulting memory errors. Inspired by experimental data, we assume that re-caching is not motivated by a deliberate effort to safeguard specific caches from theft, but by a general desire to cache more. This desire is brought on by stress, which is determined by the presence and dominance of onlookers, and by unsuccessful recovery attempts. We study this theory in two experiments similar to those done with real birds with a kind of 'virtual bird', whose behavior depends on a set of basic assumptions about corvid cognition, and a well-established model of human memory. Our results show that the 'virtual bird' acts as the real birds did; its re-caching reflects whether it has been watched, how dominant its onlooker was, and how close to that onlooker it has cached. This happens even though it cannot attribute mental states, and it has only a single behavioral rule assumed to be previously learned. Thus, our simulations indicate that corvid re-caching can be explained without sophisticated social cognition. Given our specific predictions, our theory can easily be tested empirically.

  2. Corvid re-caching without 'theory of mind': a model.

    Directory of Open Access Journals (Sweden)

    Elske van der Vaart

    Full Text Available Scrub jays are thought to use many tactics to protect their caches. For instance, they predominantly bury food far away from conspecifics, and if they must cache while being watched, they often re-cache their worms later, once they are in private. Two explanations have been offered for such observations, and they are intensely debated. First, the birds may reason about their competitors' mental states, with a 'theory of mind'; alternatively, they may apply behavioral rules learned in daily life. Although this second hypothesis is cognitively simpler, it does seem to require a different, ad-hoc behavioral rule for every caching and re-caching pattern exhibited by the birds. Our new theory avoids this drawback by explaining a large variety of patterns as side-effects of stress and the resulting memory errors. Inspired by experimental data, we assume that re-caching is not motivated by a deliberate effort to safeguard specific caches from theft, but by a general desire to cache more. This desire is brought on by stress, which is determined by the presence and dominance of onlookers, and by unsuccessful recovery attempts. We study this theory in two experiments similar to those done with real birds with a kind of 'virtual bird', whose behavior depends on a set of basic assumptions about corvid cognition, and a well-established model of human memory. Our results show that the 'virtual bird' acts as the real birds did; its re-caching reflects whether it has been watched, how dominant its onlooker was, and how close to that onlooker it has cached. This happens even though it cannot attribute mental states, and it has only a single behavioral rule assumed to be previously learned. Thus, our simulations indicate that corvid re-caching can be explained without sophisticated social cognition. Given our specific predictions, our theory can easily be tested empirically.

  3. A method cache for Patmos

    DEFF Research Database (Denmark)

    Degasperi, Philipp; Hepp, Stefan; Puffitsch, Wolfgang

    2014-01-01

    For real-time systems we need time-predictable processors. This paper presents a method cache as a time-predictable solution for instruction caching. The method cache caches whole methods (or functions) and simplifies worst-case execution time analysis. We have integrated the method cache...... in the time-predictable processor Patmos. We evaluate the method cache with a large set of embedded benchmarks. Most benchmarks show a good hit rate for a method cache size in the range between 4 and 16 KB....

  4. Maintaining Web Cache Coherency

    Directory of Open Access Journals (Sweden)

    2000-01-01

    Full Text Available Document coherency is a challenging problem for Web caching. Once the documents are cached throughout the Internet, it is often difficult to keep them coherent with the origin document without generating a new traffic that could increase the traffic on the international backbone and overload the popular servers. Several solutions have been proposed to solve this problem, among them two categories have been widely discussed: the strong document coherency and the weak document coherency. The cost and the efficiency of the two categories are still a controversial issue, while in some studies the strong coherency is far too expensive to be used in the Web context, in other studies it could be maintained at a low cost. The accuracy of these analysis is depending very much on how the document updating process is approximated. In this study, we compare some of the coherence methods proposed for Web caching. Among other points, we study the side effects of these methods on the Internet traffic. The ultimate goal is to study the cache behavior under several conditions, which will cover some of the factors that play an important role in the Web cache performance evaluation and quantify their impact on the simulation accuracy. The results presented in this study show indeed some differences in the outcome of the simulation of a Web cache depending on the workload being used, and the probability distribution used to approximate updates on the cached documents. Each experiment shows two case studies that outline the impact of the considered parameter on the performance of the cache.

  5. Compiler-Enforced Cache Coherence Using a Functional Language

    Directory of Open Access Journals (Sweden)

    Rich Wolski

    1996-01-01

    Full Text Available The cost of hardware cache coherence, both in terms of execution delay and operational cost, is substantial for scalable systems. Fortunately, compiler-generated cache management can reduce program serialization due to cache contention; increase execution performance; and reduce the cost of parallel systems by eliminating the need for more expensive hardware support. In this article, we use the Sisal functional language system as a vehicle to implement and investigate automatic, compiler-based cache management. We describe our implementation of Sisal for the IBM Power/4. The Power/4, briefly available as a product, represents an early attempt to build a shared memory machine that relies strictly on the language system for cache coherence. We discuss the issues associated with deterministic execution and program correctness on a system without hardware coherence, and demonstrate how Sisal (as a functional language is able to address those issues.

  6. Cache aware mapping of streaming apllications on a multiprocessor system-on-chip

    NARCIS (Netherlands)

    Moonen, A.J.M.; Bekooij, M.J.G.; Berg, van den R.M.J.; Meerbergen, van J.; Sciuto, D.; Peng, Z.

    2008-01-01

    Efficient use of the memory hierarchy is critical for achieving high performance in a multiprocessor system- on-chip. An external memory that is shared between processors is a bottleneck in current and future systems. Cache misses and a large cache miss penalty contribute to a low processor

  7. Web cache location

    Directory of Open Access Journals (Sweden)

    Boffey Brian

    2004-01-01

    Full Text Available Stress placed on network infrastructure by the popularity of the World Wide Web may be partially relieved by keeping multiple copies of Web documents at geographically dispersed locations. In particular, use of proxy caches and replication provide a means of storing information 'nearer to end users'. This paper concentrates on the locational aspects of Web caching giving both an overview, from an operational research point of view, of existing research and putting forward avenues for possible further research. This area of research is in its infancy and the emphasis will be on themes and trends rather than on algorithm construction. Finally, Web caching problems are briefly related to referral systems more generally.

  8. Cache Oblivious Distribution Sweeping

    DEFF Research Database (Denmark)

    Brodal, G.S.; Fagerberg, R.

    2002-01-01

    We adapt the distribution sweeping method to the cache oblivious model. Distribution sweeping is the name used for a general approach for divide-and-conquer algorithms where the combination of solved subproblems can be viewed as a merging process of streams. We demonstrate by a series of algorith...

  9. A Software Managed Stack Cache for Real-Time Systems

    DEFF Research Database (Denmark)

    Jordan, Alexander; Abbaspourseyedi, Sahar; Schoeberl, Martin

    2016-01-01

    In a real-time system, the use of a scratchpad memory can mitigate the difficulties related to analyzing data caches, whose behavior is inherently hard to predict. We propose to use a scratchpad memory for stack allocated data. While statically allocating stack frames for individual functions...

  10. Combining instruction prefetching with partial cache locking to improve WCET in real-time systems.

    Directory of Open Access Journals (Sweden)

    Fan Ni

    Full Text Available Caches play an important role in embedded systems to bridge the performance gap between fast processor and slow memory. And prefetching mechanisms are proposed to further improve the cache performance. While in real-time systems, the application of caches complicates the Worst-Case Execution Time (WCET analysis due to its unpredictable behavior. Modern embedded processors often equip locking mechanism to improve timing predictability of the instruction cache. However, locking the whole cache may degrade the cache performance and increase the WCET of the real-time application. In this paper, we proposed an instruction-prefetching combined partial cache locking mechanism, which combines an instruction prefetching mechanism (termed as BBIP with partial cache locking to improve the WCET estimates of real-time applications. BBIP is an instruction prefetching mechanism we have already proposed to improve the worst-case cache performance and in turn the worst-case execution time. The estimations on typical real-time applications show that the partial cache locking mechanism shows remarkable WCET improvement over static analysis and full cache locking.

  11. Combining instruction prefetching with partial cache locking to improve WCET in real-time systems.

    Science.gov (United States)

    Ni, Fan; Long, Xiang; Wan, Han; Gao, Xiaopeng

    2013-01-01

    Caches play an important role in embedded systems to bridge the performance gap between fast processor and slow memory. And prefetching mechanisms are proposed to further improve the cache performance. While in real-time systems, the application of caches complicates the Worst-Case Execution Time (WCET) analysis due to its unpredictable behavior. Modern embedded processors often equip locking mechanism to improve timing predictability of the instruction cache. However, locking the whole cache may degrade the cache performance and increase the WCET of the real-time application. In this paper, we proposed an instruction-prefetching combined partial cache locking mechanism, which combines an instruction prefetching mechanism (termed as BBIP) with partial cache locking to improve the WCET estimates of real-time applications. BBIP is an instruction prefetching mechanism we have already proposed to improve the worst-case cache performance and in turn the worst-case execution time. The estimations on typical real-time applications show that the partial cache locking mechanism shows remarkable WCET improvement over static analysis and full cache locking.

  12. A high level implementation and performance evaluation of level-I asynchronous cache on FPGA

    Directory of Open Access Journals (Sweden)

    Mansi Jhamb

    2017-07-01

    Full Text Available To bridge the ever-increasing performance gap between the processor and the main memory in a cost-effective manner, novel cache designs and implementations are indispensable. Cache is responsible for a major part of energy consumption (approx. 50% of processors. This paper presents a high level implementation of a micropipelined asynchronous architecture of L1 cache. Due to the fact that each cache memory implementation is time consuming and error-prone process, a synthesizable and a configurable model proves out to be of immense help as it aids in generating a range of caches in a reproducible and quick fashion. The micropipelined cache, implemented using C-Elements acts as a distributed message-passing system. The RTL cache model implemented in this paper, comprising of data and instruction caches has a wide array of configurable parameters. In addition to timing robustness our implementation has high average cache throughput and low latency. The implemented architecture comprises of two direct-mapped, write-through caches for data and instruction. The architecture is implemented in a Field Programmable Gate Array (FPGA chip using Very High Speed Integrated Circuit Hardware Description Language (VHSIC HDL along with advanced synthesis and place-and-route tools.

  13. Prefix list for each organism - Gclust Server | LSDB Archive [Life Science Database Archive metadata

    Lifescience Database Archive (English)

    Full Text Available List Contact us Gclust Server Prefix list for each organism Data detail Data name Prefix list for each organi...sm DOI 10.18908/lsdba.nbdc00464-006 Description of data contents List of prefixes for organisms used in Gcl...ust. Each prefix is applied to the top of the sequence ID according to each organism. The first line specifies the number of organi...sm species (95). From the second line, the prefix of each organi... Database Site Policy | Contact Us Prefix list for each organism - Gclust Server | LSDB Archive ...

  14. Consideration on the history and the stylistic use of prefixes

    Directory of Open Access Journals (Sweden)

    Antonio Carlos Silva de Carvalho

    2016-07-01

    Full Text Available This paper aims to discuss prefixes from a historical perspective, as well as to observe nuances of stylistic value in them. The choice of subject was basically due to two reasons: (i the considerations set out by Martins (2003 on the low stylistic productivity caused by prefixal derivation – especially if compared to suffixal derivation; and (ii the considerations set out by Silva (2009 on the so-called de-language, of negativity, in Manoel de Barros. At first we worked on a brief historically and etymologically-oriented incursion on prefixes; and then, subjecting the reflections we gathered to a punctual corpus by the author, we highlighted examples in which features of the morpho-stylistic nature that contribute to the singularity of his work, also linked to the aesthetics of the fragmentary and to the smallest beings, can be explored.

  15. On the Equational Definition of the Least Prefixed Point

    DEFF Research Database (Denmark)

    Santocanale, Luigi

    2003-01-01

    We propose a method to axiomatize by equations the least prefixed point of an order preserving function. We discuss its domain of application and show that the Boolean modal μ-calculus has a complete equational axiomatization. The method relies on the existence of a “closed structure” and its rel...

  16. On the Equational Definition of the Least Prefixed Point

    DEFF Research Database (Denmark)

    Santocanale, Luigi

    2001-01-01

    We show how to axiomatize by equations the least prefixed point of an order preserving function and discuss the domain of application of the proposed method. Thus, we generalize the well known equational axiomatization of Propositional Dynamic Logic to a complete equational axiomatization of the ...

  17. Chosen-Prefix Collisions for MD5 and Applications

    NARCIS (Netherlands)

    M.M.J. Stevens (Marc); A.K. Lenstra (Arjen); B. de Weger (Benne)

    2012-01-01

    textabstractWe present a novel, automated way to find differential paths for MD5. Its main application is in the construction of \\emph{chosen-prefix collisions}. We have shown how, at an approximate expected cost of $2^{39}$ calls to the MD5 compression function, for any two chosen

  18. Evict on write, a management strategy for a prefetch unit and/or first level cache in a multiprocessor system with speculative execution

    Science.gov (United States)

    Gara, Alan; Ohmacht, Martin

    2014-09-16

    In a multiprocessor system with at least two levels of cache, a speculative thread may run on a core processor in parallel with other threads. When the thread seeks to do a write to main memory, this access is to be written through the first level cache to the second level cache. After the write though, the corresponding line is deleted from the first level cache and/or prefetch unit, so that any further accesses to the same location in main memory have to be retrieved from the second level cache. The second level cache keeps track of multiple versions of data, where more than one speculative thread is running in parallel, while the first level cache does not have any of the versions during speculation. A switch allows choosing between modes of operation of a speculation blind first level cache.

  19. An analysis of the status of the secondary noun prefixes in Ndebele ...

    African Journals Online (AJOL)

    The article probes into the nature of secondary noun class prefixes in the morphology of some Nguni languages and Ndebele in particular. The secondary prefixes are known as commentary prefixes mainly because they carry overtones of sarcasm, criticism and caricature among other elements, through loading an implied ...

  20. Time-predictable Stack Caching

    DEFF Research Database (Denmark)

    Abbaspourseyedi, Sahar

    completely. Thus, in systems with hard deadlines the worst-case execution time (WCET) of the real-time software running on them needs to be bounded. Modern architectures use features such as pipelining and caches for improving the average performance. These features, however, make the WCET analysis more...... addresses, provides an opportunity to predict and tighten the WCET of accesses to data in caches. In this thesis, we introduce the time-predictable stack cache design and implementation within a time-predictable processor. We introduce several optimizations to our design for tightening the WCET while...... keeping the timepredictability of the design intact. Moreover, we provide a solution for reducing the cost of context switching in a system using the stack cache. In design of these caches, we use custom hardware and compiler support for delivering time-predictable stack data accesses. Furthermore...

  1. High Performance Analytics with the R3-Cache

    Science.gov (United States)

    Eavis, Todd; Sayeed, Ruhan

    Contemporary data warehouses now represent some of the world’s largest databases. As these systems grow in size and complexity, however, it becomes increasingly difficult for brute force query processing approaches to meet the performance demands of end users. Certainly, improved indexing and more selective view materialization are helpful in this regard. Nevertheless, with warehouses moving into the multi-terabyte range, it is clear that the minimization of external memory accesses must be a primary performance objective. In this paper, we describe the R 3-cache, a natively multi-dimensional caching framework designed specifically to support sophisticated warehouse/OLAP environments. R 3-cache is based upon an in-memory version of the R-tree that has been extended to support buffer pages rather than disk blocks. A key strength of the R 3-cache is that it is able to utilize multi-dimensional fragments of previous query results so as to significantly minimize the frequency and scale of disk accesses. Moreover, the new caching model directly accommodates the standard relational storage model and provides mechanisms for pro-active updates that exploit the existence of query “hot spots”. The current prototype has been evaluated as a component of the Sidera DBMS, a “shared nothing” parallel OLAP server designed for multi-terabyte analytics. Experimental results demonstrate significant performance improvements relative to simpler alternatives.

  2. The Cost of Cache-Oblivious Searching

    DEFF Research Database (Denmark)

    Bender, Michael A.; Brodal, Gerth Stølting; Fagerberg, Rolf

    2011-01-01

    of the block sizes are limited to be powers of 2. The paper gives modified versions of the van Emde Boas layout, where the expected number of memory transfers between any two levels of the memory hierarchy is arbitrarily close to [lg e+O(lg lg B/lg B)]log  B N+O(1). This factor approaches lg e≈1.443 as B...... increases. The expectation is taken over the random placement in memory of the first element of the structure. Because searching in the disk-access machine (DAM) model can be performed in log  B N+O(1) block transfers, this result establishes a separation between the (2-level) DAM model and cache...

  3. A Cache System Design for CMPs with Built-In Coherence Verification

    Directory of Open Access Journals (Sweden)

    Mamata Dalui

    2016-01-01

    Full Text Available This work reports an effective design of cache system for Chip Multiprocessors (CMPs. It introduces built-in logic for verification of cache coherence in CMPs realizing directory based protocol. It is developed around the cellular automata (CA machine, invented by John von Neumann in the 1950s. A special class of CA referred to as single length cycle 2-attractor cellular automata (TACA has been planted to detect the inconsistencies in cache line states of processors’ private caches. The TACA module captures coherence status of the CMPs’ cache system and memorizes any inconsistent recording of the cache line states during the processors’ reference to a memory block. Theory has been developed to empower a TACA to analyse the cache state updates and then to settle to an attractor state indicating quick decision on a faulty recording of cache line status. The introduction of segmentation of the CMPs’ processor pool ensures a better efficiency, in determining the inconsistencies, by reducing the number of computation steps in the verification logic. The hardware requirement for the verification logic points to the fact that the overhead of proposed coherence verification module is much lesser than that of the conventional verification units and is insignificant with respect to the cost involved in CMPs’ cache system.

  4. On the Limits of Cache-Obliviousness

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Fagerberg, Rolf

    2003-01-01

    In this paper, we present lower bounds for permuting and sorting in the cache-oblivious model. We prove that (1) I/O optimal cache-oblivious comparison based sorting is not possible without a tall cache assumption, and (2) there does not exist an I/O optimal cache-oblivious algorithm for permutin...

  5. FPS-RAM: Fast Prefix Search RAM-Based Hardware for Forwarding Engine

    Science.gov (United States)

    Zaitsu, Kazuya; Yamamoto, Koji; Kuroda, Yasuto; Inoue, Kazunari; Ata, Shingo; Oka, Ikuo

    Ternary content addressable memory (TCAM) is becoming very popular for designing high-throughput forwarding engines on routers. However, TCAM has potential problems in terms of hardware and power costs, which limits its ability to deploy large amounts of capacity in IP routers. In this paper, we propose new hardware architecture for fast forwarding engines, called fast prefix search RAM-based hardware (FPS-RAM). We designed FPS-RAM hardware with the intent of maintaining the same search performance and physical user interface as TCAM because our objective is to replace the TCAM in the market. Our RAM-based hardware architecture is completely different from that of TCAM and has dramatically reduced the costs and power consumption to 62% and 52%, respectively. We implemented FPS-RAM on an FPGA to examine its lookup operation.

  6. Using the Sadakane Compressed Suffix Tree to Solve the All-Pairs Suffix-Prefix Problem

    Directory of Open Access Journals (Sweden)

    Maan Haj Rachid

    2014-01-01

    Full Text Available The all-pairs suffix-prefix matching problem is a basic problem in string processing. It has an application in the de novo genome assembly task, which is one of the major bioinformatics problems. Due to the large size of the input data, it is crucial to use fast and space efficient solutions. In this paper, we present a space-economical solution to this problem using the generalized Sadakane compressed suffix tree. Furthermore, we present a parallel algorithm to provide more speed for shared memory computers. Our sequential and parallel algorithms are optimized by exploiting features of the Sadakane compressed index data structure. Experimental results show that our solution based on the Sadakane’s compressed index consumes significantly less space than the ones based on noncompressed data structures like the suffix tree and the enhanced suffix array. Our experimental results show that our parallel algorithm is efficient and scales well with increasing number of processors.

  7. Cache Performance Optimization for SoC Vedio Applications

    OpenAIRE

    Lei Li; Wei Zhang; HuiYao An; Xing Zhang; HuaiQi Zhu

    2014-01-01

    Chip Multiprocessors (CMPs) are adopted by industry to deal with the speed limit of the single-processor. But memory access has become the bottleneck of the performance, especially in multimedia applications. In this paper, a set of management policies is proposed to improve the cache performance for a SoC platform of video application. By analyzing the behavior of Vedio Engine, the memory-friendly writeback and efficient prefetch policies are adopted. The experiment platform is simulated by ...

  8. Efficacy of Code Optimization on Cache-Based Processors

    Science.gov (United States)

    VanderWijngaart, Rob F.; Saphir, William C.; Chancellor, Marisa K. (Technical Monitor)

    1997-01-01

    In this paper a number of techniques for improving the cache performance of a representative piece of numerical software is presented. Target machines are popular processors from several vendors: MIPS R5000 (SGI Indy), MIPS R8000 (SGI PowerChallenge), MIPS R10000 (SGI Origin), DEC Alpha EV4 + EV5 (Cray T3D & T3E), IBM RS6000 (SP Wide-node), Intel PentiumPro (Ames' Whitney), Sun UltraSparc (NERSC's NOW). The optimizations all attempt to increase the locality of memory accesses. But they meet with rather varied and often counterintuitive success on the different computing platforms. We conclude that it may be genuinely impossible to obtain portable performance on the current generation of cache-based machines. At the least, it appears that the performance of modern commodity processors cannot be described with parameters defining the cache alone.

  9. IP lookup with low memory requirement and fast update

    DEFF Research Database (Denmark)

    Berger, Michael Stübert

    2003-01-01

    The paper presents an IP address lookup algorithm with low memory requirement and fast updates. The scheme, which is denoted prefix-tree, uses a combination of a trie and a tree search, which is efficient in memory usage because the tree contains exactly one node for each prefix in the routing...

  10. Model checking a cache coherence protocol for a Java DSM implementation

    NARCIS (Netherlands)

    J. Pang; W.J. Fokkink (Wan); R. Hofman (Rutger); R. Veldema

    2007-01-01

    textabstractJackal is a fine-grained distributed shared memory implementation of the Java programming language. It aims to implement Java's memory model and allows multithreaded Java programs to run unmodified on a distributed memory system. It employs a multiple-writer cache coherence

  11. Model checking a cache coherence protocol of a Java DSM implementation

    NARCIS (Netherlands)

    Pang, J.; Fokkink, W.J.; Hofman, R.; Veldema, R.S.

    2007-01-01

    Jackal is a fine-grained distributed shared memory implementation of the Java programming language. It aims to implement Java's memory model and allows multithreaded Java programs to run unmodified on a distributed memory system. It employs a multiple-writer cache coherence protocol. In this paper,

  12. Differential hippocampal gene expression is associated with climate-related natural variation in memory and the hippocampus in food-caching chickadees.

    Science.gov (United States)

    Pravosudov, V V; Roth, T C; Forister, M L; Ladage, L D; Kramer, R; Schilkey, F; van der Linden, A M

    2013-01-01

    There is significant and often heritable variation in cognition and its underlying neural mechanisms, yet specific genetic contributions to such variation are not well characterized. Black-capped chickadees present a good model to investigate the genetic basis of cognition because they exhibit tremendous climate-related variation in memory, hippocampal morphology and neurogenesis rates throughout the North American continent, and these cognitive traits appear to have a heritable basis. We examined the hippocampal transcriptome profiles of laboratory-reared chickadees from the two most divergent populations to test whether differential gene expression in the hippocampus is associated with population differences in spatial memory, hippocampal morphology and adult hippocampal neurogenesis rates. Using high-resolution mRNA sequencing coupled to a de novo transcriptome assembly, we generated 23 295 consensus sequences, which predicted 16 206 protein sequences with 13 982 showing high similarity to known protein sequences or conserved hypothetical proteins in other species. Of these, we identified differential expression in nearly 380 genes, with 47 genes specifically linked to neurogenesis, apoptosis, synaptic function, and learning and memory processes. Many of the other differentially expressed genes, however, may be associated with other functions. Our study presents the first avian hippocampal transcriptome, and it is the first study identifying differential gene expression associated with natural variation in cognition and the hippocampus. Our results provide additional support to the hypothesis that population differences in memory, hippocampal morphology and neurogenesis in chickadees have likely resulted from natural selection that appears to act on memory and its underlying neural mechanisms. © 2012 Blackwell Publishing Ltd.

  13. Undecidability Results for Bisimilarity on Prefix Rewrite Systems

    DEFF Research Database (Denmark)

    Jancar, Petr; Srba, Jiri

    2006-01-01

    We answer an open question related to bisimilarity checking on labelled transition systems generated by prefix rewrite rules on words. Stirling (1996, 1998) proved the decidability of bisimilarity for normed pushdown processes. This result was substantially extended by Senizergues (1998, 2005) who...... language) was left open; this was repeatedly indicated by both Stirling and Senizergues. Here we answer the question negatively, i.e., we show undecidability of bisimilarity on Type -1 systems, even in the normed case. We complete the picture by considering classes of systems that use rewrite rules...

  14. Re-caching by Western scrub-jays (Aphelocoma californica cannot be attributed to stress.

    Directory of Open Access Journals (Sweden)

    James M Thom

    Full Text Available Western scrub-jays (Aphelocoma californica live double lives, storing food for the future while raiding the stores of other birds. One tactic scrub-jays employ to protect stores is "re-caching"-relocating caches out of sight of would-be thieves. Recent computational modelling work suggests that re-caching might be mediated not by complex cognition, but by a combination of memory failure and stress. The "Stress Model" asserts that re-caching is a manifestation of a general drive to cache, rather than a desire to protect existing stores. Here, we present evidence strongly contradicting the central assumption of these models: that stress drives caching, irrespective of social context. In Experiment (i, we replicate the finding that scrub-jays preferentially relocate food they were watched hiding. In Experiment (ii we find no evidence that stress increases caching. In light of our results, we argue that the Stress Model cannot account for scrub-jay re-caching.

  15. Optimal and Scalable Caching for 5G Using Reinforcement Learning of Space-Time Popularities

    Science.gov (United States)

    Sadeghi, Alireza; Sheikholeslami, Fatemeh; Giannakis, Georgios B.

    2018-02-01

    Small basestations (SBs) equipped with caching units have potential to handle the unprecedented demand growth in heterogeneous networks. Through low-rate, backhaul connections with the backbone, SBs can prefetch popular files during off-peak traffic hours, and service them to the edge at peak periods. To intelligently prefetch, each SB must learn what and when to cache, while taking into account SB memory limitations, the massive number of available contents, the unknown popularity profiles, as well as the space-time popularity dynamics of user file requests. In this work, local and global Markov processes model user requests, and a reinforcement learning (RL) framework is put forth for finding the optimal caching policy when the transition probabilities involved are unknown. Joint consideration of global and local popularity demands along with cache-refreshing costs allow for a simple, yet practical asynchronous caching approach. The novel RL-based caching relies on a Q-learning algorithm to implement the optimal policy in an online fashion, thus enabling the cache control unit at the SB to learn, track, and possibly adapt to the underlying dynamics. To endow the algorithm with scalability, a linear function approximation of the proposed Q-learning scheme is introduced, offering faster convergence as well as reduced complexity and memory requirements. Numerical tests corroborate the merits of the proposed approach in various realistic settings.

  16. Minimizing cache misses in an event-driven network server: A case study of TUX

    DEFF Research Database (Denmark)

    Bhatia, Sapan; Consel, Charles; Lawall, Julia Laetitia

    2006-01-01

    We analyze the performance of CPU-bound network servers and demonstrate experimentally that the degradation in the performance of these servers under high-concurrency workloads is largely due to inefficient use of the hardware caches. We then describe an approach to speeding up event-driven network...... servers by optimizing their use of the L2 CPU cache in the context of the TUX Web server, known for its robustness to heavy load. Our approach is based on a novel cache-aware memory allocator and a specific scheduling strategy that together ensure that the total working data set of the server stays...

  17. Automated Cache Performance Analysis And Optimization

    Energy Technology Data Exchange (ETDEWEB)

    Mohror, Kathryn [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2013-12-23

    While there is no lack of performance counter tools for coarse-grained measurement of cache activity, there is a critical lack of tools for relating data layout to cache behavior to application performance. Generally, any nontrivial optimizations are either not done at all, or are done ”by hand” requiring significant time and expertise. To the best of our knowledge no tool available to users measures the latency of memory reference instructions for partic- ular addresses and makes this information available to users in an easy-to-use and intuitive way. In this project, we worked to enable the Open|SpeedShop performance analysis tool to gather memory reference latency information for specific instructions and memory ad- dresses, and to gather and display this information in an easy-to-use and intuitive way to aid performance analysts in identifying problematic data structures in their codes. This tool was primarily designed for use in the supercomputer domain as well as grid, cluster, cloud-based parallel e-commerce, and engineering systems and middleware. Ultimately, we envision a tool to automate optimization of application cache layout and utilization in the Open|SpeedShop performance analysis tool. To commercialize this soft- ware, we worked to develop core capabilities for gathering enhanced memory usage per- formance data from applications and create and apply novel methods for automatic data structure layout optimizations, tailoring the overall approach to support existing supercom- puter and cluster programming models and constraints. In this Phase I project, we focused on infrastructure necessary to gather performance data and present it in an intuitive way to users. With the advent of enhanced Precise Event-Based Sampling (PEBS) counters on recent Intel processor architectures and equivalent technology on AMD processors, we are now in a position to access memory reference information for particular addresses. Prior to the introduction of PEBS counters

  18. Scalable parallel prefix solvers for discrete ordinates transport

    International Nuclear Information System (INIS)

    Pautz, S.; Pandya, T.; Adams, M.

    2009-01-01

    The well-known 'sweep' algorithm for inverting the streaming-plus-collision term in first-order deterministic radiation transport calculations has some desirable numerical properties. However, it suffers from parallel scaling issues caused by a lack of concurrency. The maximum degree of concurrency, and thus the maximum parallelism, grows more slowly than the problem size for sweeps-based solvers. We investigate a new class of parallel algorithms that involves recasting the streaming-plus-collision problem in prefix form and solving via cyclic reduction. This method, although computationally more expensive at low levels of parallelism than the sweep algorithm, offers better theoretical scalability properties. Previous work has demonstrated this approach for one-dimensional calculations; we show how to extend it to multidimensional calculations. Notably, for multiple dimensions it appears that this approach is limited to long-characteristics discretizations; other discretizations cannot be cast in prefix form. We implement two variants of the algorithm within the radlib/SCEPTRE transport code library at Sandia National Laboratories and show results on two different massively parallel systems. Both the 'forward' and 'symmetric' solvers behave similarly, scaling well to larger degrees of parallelism then sweeps-based solvers. We do observe some issues at the highest levels of parallelism (relative to the system size) and discuss possible causes. We conclude that this approach shows good potential for future parallel systems, but the parallel scalability will depend heavily on the architecture of the communication networks of these systems. (authors)

  19. Non-monotonic Pre-fixed Points and Learning

    Directory of Open Access Journals (Sweden)

    Stefano Berardi

    2013-08-01

    Full Text Available We consider the problem of finding pre-fixed points of interactive realizers over arbitrary knowledge spaces, obtaining a relative recursive procedure. Knowledge spaces and interactive realizers are an abstract setting to represent learning processes, that can interpret non-constructive proofs. Atomic pieces of information of a knowledge space are stratified into levels, and evaluated into truth values depending on knowledge states. Realizers are then used to define operators that extend a given state by adding and possibly removing atoms: in a learning process states of knowledge change nonmonotonically. Existence of a pre-fixed point of a realizer is equivalent to the termination of the learning process with some state of knowledge which is free of patent contradictions and such that there is nothing to add. In this paper we generalize our previous results in the case of level 2 knowledge spaces and deterministic operators to the case of omega-level knowledge spaces and of non-deterministic operators.

  20. Cache-Aware and Cache-Oblivious Adaptive Sorting

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Fagerberg, Rolf; Moruz, Gabriel

    2005-01-01

    Two new adaptive sorting algorithms are introduced which perform an optimal number of comparisons with respect to the number of inversions in the input. The first algorithm is based on a new linear time reduction to (non-adaptive) sorting. The second algorithm is based on a new division protocol...... for the GenericSort algorithm by Estivill-Castro and Wood. From both algorithms we derive I/O-optimal cache-aware and cache-oblivious adaptive sorting algorithms. These are the first I/O-optimal adaptive sorting algorithms....

  1. Mitochondrial genomic analysis of late onset Alzheimer's disease reveals protective haplogroups H6A1A/H6A1B: the Cache County Study on Memory in Aging.

    Directory of Open Access Journals (Sweden)

    Perry G Ridge

    Full Text Available Alzheimer's disease (AD is the most common cause of dementia and AD risk clusters within families. Part of the familial aggregation of AD is accounted for by excess maternal vs. paternal inheritance, a pattern consistent with mitochondrial inheritance. The role of specific mitochondrial DNA (mtDNA variants and haplogroups in AD risk is uncertain.We determined the complete mitochondrial genome sequence of 1007 participants in the Cache County Study on Memory in Aging, a population-based prospective cohort study of dementia in northern Utah. AD diagnoses were made with a multi-stage protocol that included clinical examination and review by a panel of clinical experts. We used TreeScanning, a statistically robust approach based on haplotype networks, to analyze the mtDNA sequence data. Participants with major mitochondrial haplotypes H6A1A and H6A1B showed a reduced risk of AD (p=0.017, corrected for multiple comparisons. The protective haplotypes were defined by three variants: m.3915G>A, m.4727A>G, and m.9380G>A. These three variants characterize two different major haplogroups. Together m.4727A>G and m.9380G>A define H6A1, and it has been suggested m.3915G>A defines H6A. Additional variants differentiate H6A1A and H6A1B; however, none of these variants had a significant relationship with AD case-control status.Our findings provide evidence of a reduced risk of AD for individuals with mtDNA haplotypes H6A1A and H6A1B. These findings are the results of the largest study to date with complete mtDNA genome sequence data, yet the functional significance of the associated haplotypes remains unknown and replication in others studies is necessary.

  2. Cache-Oblivious Red-Blue Line Segment Intersection

    DEFF Research Database (Denmark)

    Arge, Lars; Mølhave, Thomas; Zeh, Norbert

    2008-01-01

    We present an optimal cache-oblivious algorithm for finding all intersections between a set of non-intersecting red segments and a set of non-intersecting blue segments in the plane. Our algorithm uses $O(\\frac{N}{B}\\log_{M/B}\\frac{N}{B}+T/B)$ memory transfers, where N is the total number...... of segments, M and B are the memory and block transfer sizes of any two consecutive levels of any multilevel memory hierarchy, and T is the number of intersections....

  3. Monotonic Set-Extended Prefix Rewriting and Verification of Recursive Ping-Pong Protocols

    DEFF Research Database (Denmark)

    Delzanno, Giorgio; Esparza, Javier; Srba, Jiri

    2006-01-01

    of messages) some verification problems become decidable. In particular we give an algorithm to decide control state reachability, a problem related to security properties like secrecy and authenticity. The proof is via a reduction to a new prefix rewriting model called Monotonic Set-extended Prefix rewriting...

  4. Massively parallel algorithms for trace-driven cache simulations

    Science.gov (United States)

    Nicol, David M.; Greenberg, Albert G.; Lubachevsky, Boris D.

    1991-01-01

    Trace driven cache simulation is central to computer design. A trace is a very long sequence of reference lines from main memory. At the t(exp th) instant, reference x sub t is hashed into a set of cache locations, the contents of which are then compared with x sub t. If at the t sup th instant x sub t is not present in the cache, then it is said to be a miss, and is loaded into the cache set, possibly forcing the replacement of some other memory line, and making x sub t present for the (t+1) sup st instant. The problem of parallel simulation of a subtrace of N references directed to a C line cache set is considered, with the aim of determining which references are misses and related statistics. A simulation method is presented for the Least Recently Used (LRU) policy, which regradless of the set size C runs in time O(log N) using N processors on the exclusive read, exclusive write (EREW) parallel model. A simpler LRU simulation algorithm is given that runs in O(C log N) time using N/log N processors. Timings are presented of the second algorithm's implementation on the MasPar MP-1, a machine with 16384 processors. A broad class of reference based line replacement policies are considered, which includes LRU as well as the Least Frequently Used and Random replacement policies. A simulation method is presented for any such policy that on any trace of length N directed to a C line set runs in the O(C log N) time with high probability using N processors on the EREW model. The algorithms are simple, have very little space overhead, and are well suited for SIMD implementation.

  5. Cache-Oblivious Hashing

    DEFF Research Database (Denmark)

    Pagh, Rasmus; Wei, Zhewei; Yi, Ke

    2014-01-01

    The hash table, especially its external memory version, is one of the most important index structures in large databases. Assuming a truly random hash function, it is known that in a standard external hash table with block size b, searching for a particular key only takes expected average t q =1...

  6. Conditional load and store in a shared memory

    Science.gov (United States)

    Blumrich, Matthias A; Ohmacht, Martin

    2015-02-03

    A method, system and computer program product for implementing load-reserve and store-conditional instructions in a multi-processor computing system. The computing system includes a multitude of processor units and a shared memory cache, and each of the processor units has access to the memory cache. In one embodiment, the method comprises providing the memory cache with a series of reservation registers, and storing in these registers addresses reserved in the memory cache for the processor units as a result of issuing load-reserve requests. In this embodiment, when one of the processor units makes a request to store data in the memory cache using a store-conditional request, the reservation registers are checked to determine if an address in the memory cache is reserved for that processor unit. If an address in the memory cache is reserved for that processor, the data are stored at this address.

  7. Magpies can use local cues to retrieve their food caches.

    Science.gov (United States)

    Feenders, Gesa; Smulders, Tom V

    2011-03-01

    Much importance has been placed on the use of spatial cues by food-hoarding birds in the retrieval of their caches. In this study, we investigate whether food-hoarding birds can be trained to use local cues ("beacons") in their cache retrieval. We test magpies (Pica pica) in an active hoarding-retrieval paradigm, where local cues are always reliable, while spatial cues are not. Our results show that the birds use the local cues to retrieve their caches, even when occasionally contradicting spatial information is available. The design of our study does not allow us to test rigorously whether the birds prefer using local over spatial cues, nor to investigate the process through which they learn to use local cues. We furthermore provide evidence that magpies develop landmark preferences, which improve their retrieval accuracy. Our findings support the hypothesis that birds are flexible in their use of memory information, using a combination of the most reliable or salient information to retrieve their caches. © Springer-Verlag 2010

  8. Caching web service for TICF project

    International Nuclear Information System (INIS)

    Pais, V.F.; Stancalie, V.

    2008-01-01

    A caching web service was developed to allow caching of any object to a network cache, presented in the form of a web service. This application was used to increase the speed of previously implemented web services and for new ones. Various tests were conducted to determine the impact of using this caching web service in the existing network environment and where it should be placed in order to achieve the greatest increase in performance. Since the cache is presented to applications as a web service, it can also be used for remote access to stored data and data sharing between applications

  9. Impact of Cyclic Prefix length on OFDM system Capacity

    DEFF Research Database (Denmark)

    Rom, Christian; Sørensen, Troels Bundgaard; Mogensen, Preben Elgaard

    2005-01-01

    This paper is a study on the impact of the Cyclic Prefix (CP) length on the downlink Capacity in a base-band synchronized SISO-OFDM context. To measure this impact, the capacity, measured in bits per second per hertz, is chosen as quality parameter. The study shows how the lengthening of the CP......) the useful OFDM symbol duration, 2) the Signal to Noise Ratio (SNR) at the receiver and 3) the channel Power Delay Profile (PDP). Depending on the values of these parameters different optimum CP lengths are obtained. For a system using only one value of CP length we suggest an optimum value to be 4us...... for an OFDM symbol length of 40us and 6us for an OFDM symbol length of 80us....

  10. Enabling MPEG-2 video playback in embedded systems through improved data cache efficiency

    Science.gov (United States)

    Soderquist, Peter; Leeser, Miriam E.

    1999-01-01

    Digital video decoding, enabled by the MPEG-2 Video standard, is an important future application for embedded systems, particularly PDAs and other information appliances. Many such system require portability and wireless communication capabilities, and thus face severe limitations in size and power consumption. This places a premium on integration and efficiency, and favors software solutions for video functionality over specialized hardware. The processors in most embedded system currently lack the computational power needed to perform video decoding, but a related and equally important problem is the required data bandwidth, and the need to cost-effectively insure adequate data supply. MPEG data sets are very large, and generate significant amounts of excess memory traffic for standard data caches, up to 100 times the amount required for decoding. Meanwhile, cost and power limitations restrict cache sizes in embedded systems. Some systems, including many media processors, eliminate caches in favor of memories under direct, painstaking software control in the manner of digital signal processors. Yet MPEG data has locality which caches can exploit if properly optimized, providing fast, flexible, and automatic data supply. We propose a set of enhancements which target the specific needs of the heterogeneous types within the MPEG decoder working set. These optimizations significantly improve the efficiency of small caches, reducing cache-memory traffic by almost 70 percent, and can make an enhanced 4 KB cache perform better than a standard 1 MB cache. This performance improvement can enable high-resolution, full frame rate video playback in cheaper, smaller system than woudl otherwise be possible.

  11. A Time-predictable Stack Cache

    DEFF Research Database (Denmark)

    Abbaspour, Sahar; Brandner, Florian; Schoeberl, Martin

    2013-01-01

    Real-time systems need time-predictable architectures to support static worst-case execution time (WCET) analysis. One architectural feature, the data cache, is hard to analyze when different data areas (e.g., heap allocated and stack allocated data) share the same cache. This sharing leads to le...... of a cache for stack allocated data. Our port of the LLVM C++ compiler supports the management of the stack cache. The combination of stack cache instructions and the hardware implementation of the stack cache is a further step towards timepredictable architectures.......Real-time systems need time-predictable architectures to support static worst-case execution time (WCET) analysis. One architectural feature, the data cache, is hard to analyze when different data areas (e.g., heap allocated and stack allocated data) share the same cache. This sharing leads to less...... precise results of the cache analysis part of the WCET analysis. Splitting the data cache for different data areas enables composable data cache analysis. The WCET analysis tool can analyze the accesses to these different data areas independently. In this paper we present the design and implementation...

  12. A Scalable and Highly Configurable Cache-Aware Hybrid Flash Translation Layer

    Directory of Open Access Journals (Sweden)

    Jalil Boukhobza

    2014-03-01

    Full Text Available This paper presents a cache-aware configurable hybrid flash translation layer (FTL, named CACH-FTL. It was designed based on the observation that most state-of­­-the-art flash-specific cache systems above FTLs flush groups of pages belonging to the same data block. CACH-FTL relies on this characteristic to optimize flash write operations placement, as large groups of pages are flushed to a block-mapped region, named BMR, whereas small groups are buffered into a page-mapped region, named PMR. Page group placement is based on a configurable threshold defining the limit under which it is more cost-effective to use page mapping (PMR and wait for grouping more pages before flushing to the BMR. CACH-FTL is scalable in terms of mapping table size and flexible in terms of Input/Output (I/O workload support. CACH-FTL performs very well, as the performance difference with the ideal page-mapped FTL is less than 15% in most cases and has a mean of 4% for the best CACH-FTL configurations, while using at least 78% less memory for table mapping storage on RAM.

  13. Research on Cache Placement in ICN

    Directory of Open Access Journals (Sweden)

    Yu Zhang

    2017-08-01

    Full Text Available Ubiquitous in-network caching is one of key features of Information Centric Network, together with receiver-drive content retrieval paradigm, Information Centric Network is better support for content distribution, multicast, mobility, etc. Cache placement strategy is crucial to improving utilization of cache space and reducing the occupation of link bandwidth. Most of the literature about caching policies considers the overall cost and bandwidth, but ignores the limits of node cache capacity. This paper proposes a G-FMPH algorithm which takes into ac-count both constrains on the link bandwidth and the cache capacity of nodes. Our algorithm aims at minimizing the overall cost of contents caching afterwards. The simulation results have proved that our proposed algorithm has a better performance.

  14. CryptoCache: A Secure Sharable File Cache for Roaming Users

    DEFF Research Database (Denmark)

    Jensen, Christian D.

    2000-01-01

    . Conventional distributed file systems cache everything locally or not at all; there is no possibility to cache files on nearby nodes.In this paper we present the design of a secure cache system called CryptoCache that allows roaming users to cache files on untrusted file hosting servers. The system allows...... flexible sharing of cached files among unauthenticated users, i.e. unlike most distributed file systems CryptoCache does not require a global authentication framework.Files are encrypted when they are transferred over the network and while stored on untrusted servers. The system uses public key......Small mobile computers are now sufficiently powerful to run many applications, but storage capacity remains limited so working files cannot be cached or stored locally. Even if files can be stored locally, the mobile device is not powerful enough to act as server in collaborations with other users...

  15. Cache and energy efficient algorithms for Nussinov's RNA Folding.

    Science.gov (United States)

    Zhao, Chunchun; Sahni, Sartaj

    2017-12-06

    An RNA folding/RNA secondary structure prediction algorithm determines the non-nested/pseudoknot-free structure by maximizing the number of complementary base pairs and minimizing the energy. Several implementations of Nussinov's classical RNA folding algorithm have been proposed. Our focus is to obtain run time and energy efficiency by reducing the number of cache misses. Three cache-efficient algorithms, ByRow, ByRowSegment and ByBox, for Nussinov's RNA folding are developed. Using a simple LRU cache model, we show that the Classical algorithm of Nussinov has the highest number of cache misses followed by the algorithms Transpose (Li et al.), ByRow, ByRowSegment, and ByBox (in this order). Extensive experiments conducted on four computational platforms-Xeon E5, AMD Athlon 64 X2, Intel I7 and PowerPC A2-using two programming languages-C and Java-show that our cache efficient algorithms are also efficient in terms of run time and energy. Our benchmarking shows that, depending on the computational platform and programming language, either ByRow or ByBox give best run time and energy performance. The C version of these algorithms reduce run time by as much as 97.2% and energy consumption by as much as 88.8% relative to Classical and by as much as 56.3% and 57.8% relative to Transpose. The Java versions reduce run time by as much as 98.3% relative to Classical and by as much as 75.2% relative to Transpose. Transpose achieves run time and energy efficiency at the expense of memory as it takes twice the memory required by Classical. The memory required by ByRow, ByRowSegment, and ByBox is the same as that of Classical. As a result, using the same amount of memory, the algorithms proposed by us can solve problems up to 40% larger than those solvable by Transpose.

  16. Cache-Oblivious Planar Orthogonal Range Searching and Counting

    DEFF Research Database (Denmark)

    Arge, Lars; Brodal, Gerth Stølting; Fagerberg, Rolf

    2005-01-01

    present the first cache-oblivious data structure for planar orthogonal range counting, and improve on previous results for cache-oblivious planar orthogonal range searching. Our range counting structure uses O(Nlog2 N) space and answers queries using O(logB N) memory transfers, where B is the block...... size of any memory level in a multilevel memory hierarchy. Using bit manipulation techniques, the space can be further reduced to O(N). The structure can also be modified to support more general semigroup range sum queries in O(logB N) memory transfers, using O(Nlog2 N) space for three-sided queries...... and O(Nlog22 N/log2log2 N) space for four-sided queries. Based on the O(Nlog N) space range counting structure, we develop a data structure that uses O(Nlog2 N) space and answers three-sided range queries in O(logB N+T/B) memory transfers, where T is the number of reported points. Based...

  17. Implementació d'una Cache per a un processador MIPS d'una FPGA

    OpenAIRE

    Riera Villanueva, Marc

    2013-01-01

    [CATALÀ] Primer s'explicarà breument l'arquitectura d'un MIPS, la jerarquia de memòria i el funcionament de la cache. Posteriorment s'explicarà com s'ha dissenyat i implementat una jerarquia de memòria per a un MIPS implementat en VHDL en una FPGA. [ANGLÈS] First, the MIPS architecture, memory hierarchy and the functioning of the cache will be explained briefly. Then, the design and implementation of a memory hierarchy for a MIPS processor implemented in VHDL on an FPGA will be explained....

  18. Time and the event: The semantics of Russian prefixes

    Directory of Open Access Journals (Sweden)

    Gillian Ramchand

    2005-03-01

    Full Text Available In this paper, I draw on data from prefixation in Russian to argue for a basic distinction between event structure and temporal struc- ture. I present a linguistic semantics of verb and argument structure interpretation on the one hand, and a formal semantic implementa- tion of 'telicity' on the other, which makes sense of the generalisations apparently common to both domains. I will claim that the temporal domain embeds the event structure domain, and that the latter con- strains the former. At the same time, the different formal primitives that operate at the levels proposed form the basis for a principled linguistic distinction between the two tiers of composition: the event structure level encodes subevental relations and predicational rela- tions within those subevents; the temporal structure level introduces a t variable explicitly and relates it to the structure built up by the event level. Whether the event structure is homogenous or not will have an impact on whether the temporal variable chosen will be 'def- inite' or 'indefinite.' This latter claim then forms the basis for a new conception of the difference between perfective and imperfective verb forms in Russian.

  19. Dynamic Allocation of SPM Based on Time-Slotted Cache Conflict Graph for System Optimization

    Science.gov (United States)

    Wu, Jianping; Ling, Ming; Zhang, Yang; Mei, Chen; Wang, Huan

    This paper proposes a novel dynamic Scratch-pad Memory allocation strategy to optimize the energy consumption of the memory sub-system. Firstly, the whole program execution process is sliced into several time slots according to the temporal dimension; thereafter, a Time-Slotted Cache Conflict Graph (TSCCG) is introduced to model the behavior of Data Cache (D-Cache) conflicts within each time slot. Then, Integer Nonlinear Programming (INP) is implemented, which can avoid time-consuming linearization process, to select the most profitable data pages. Virtual Memory System (VMS) is adopted to remap those data pages, which will cause severe Cache conflicts within a time slot, to SPM. In order to minimize the swapping overhead of dynamic SPM allocation, a novel SPM controller with a tightly coupled DMA is introduced to issue the swapping operations without CPU's intervention. Last but not the least, this paper discusses the fluctuation of system energy profit based on different MMU page size as well as the Time Slot duration quantitatively. According to our design space exploration, the proposed method can optimize all of the data segments, including global data, heap and stack data in general, and reduce the total energy consumption by 27.28% on average, up to 55.22% with a marginal performance promotion. And comparing to the conventional static CCG (Cache Conflicts Graph), our approach can obtain 24.7% energy profit on average, up to 30.5% with a sight boost in performance.

  20. CacheCard : Caching static and dynamic content on the NIC

    NARCIS (Netherlands)

    Bos, Herbert; Huang, Kaiming

    2009-01-01

    CacheCard is a NIC-based cache for static and dynamic web content in a way that allows for implementation on simple devices like NICs. It requires neither understanding of the way dynamic data is generated, nor execution of scripts on the cache. By monitoring file system activity and potential

  1. Suffixing, prefixing, and the functional order of regularities in meaningful strings

    Directory of Open Access Journals (Sweden)

    Ramscar Michael

    2013-01-01

    Full Text Available The world’s languages tend to exhibit a suffixing preference, adding inflections to the ends of words, rather than the beginning of them. Previous works has suggested that this apparently universal preference arises out of the constraints imposed by general purpose learning mechanisms in the brain, and specifically, the kinds of information structures that facilitate discrimination learning (St Clair, Monaghan, & Ramscar, 2009. Here I show that learning theory predicts that prefixes and suffixes will tend to promote different kinds of learning: prefixes will facilitate the learning of the probabilities that any following elements in a sequence will follow a label, whereas suffixing will promote the abstraction of common dimensions from a set of preceding elements. The results of the artificial language learning experiment support this analysis: When words are learned with consistent prefixes, participants learned the relationship between the prefixes and the noun labels, and the relationship between the noun labels and the objects associated with them, better than when words were learned with consistent suffixes. When words were learned with consistent suffixes, participants treated similarly suffixed nouns as being more similar than nouns learned with consistent prefixes. It appears that while prefixes tend to make items more predictable and to make veridical discriminations easier, suffixes tended to make items cohere more, increasing the similarities between them.

  2. Cache-Oblivious Search Trees via Binary Trees of Small Height

    DEFF Research Database (Denmark)

    Brodal, G.S.; Fagerberg, R.; Jacob, R.

    2002-01-01

    We propose a version of cache oblivious search trees which is simpler than the previous proposal of Bender, Demaine and Farach-Colton and has the same complexity bounds. In particular, our data structure avoids the use of weight balanced B-trees, and can be implemented as just a single array......, and range queries in worst case O(logB n + k/B) memory transfers, where k is the size of the output.The basic idea of our data structure is to maintain a dynamic binary tree of height log n+O(1) using existing methods, embed this tree in a static binary tree, which in turn is embedded in an array in a cache...... oblivious fashion, using the van Emde Boas layout of Prokop.We also investigate the practicality of cache obliviousness in the area of search trees, by providing an empirical comparison of different methods for laying out a search tree in memory....

  3. Improving performance of single-path code through a time-predictable memory hierarchy

    DEFF Research Database (Denmark)

    Cilku, Bekim; Puffitsch, Wolfgang; Prokesch, Daniel

    2017-01-01

    -predictable memory hierarchy with a prefetcher that exploits the predictability of execution traces in single-path code to speed up code execution. The new memory hierarchy reduces both the cache-miss penalty time and the cache-miss rate on the instruction cache. The benefit of the approach is demonstrated through...

  4. From verbal prefixes to direction/result markers in Romance

    Directory of Open Access Journals (Sweden)

    Patrizia Cordin

    2011-12-01

    Full Text Available In this paper I analyze verb-locative constructions in Romance. Even though not allowed in standard Romance languages, which have maintained and codified the classical Latin prefix system, these constructions are widely attested in non standard varieties, that are scarcely (or not at all regularized. In this paper I deal in particular with a northern Italian variety, Trentino, where locatives, combining with some classes of verbs (unaccusative verbs and transitive activity verbs can express not only concrete direction and metaphorical direction, but also aspect (the result of an activity or the progress of a process; in other words, they can express an abstract, more grammaticalized feature of direction. In fact, Trentino verb-locative constructions can express a specific phase of the development of an event, often the result (end-point of an activity, or the start-point, or the progress, or the intensity of the activity itself. I argue that in Trentino (and in other similar dialectal varieties locatives can function as grammatical markers both for arguments (in combination with motion verbs and for aspect (in combination with verbs involving the feature of an abstract path. In a more general context, I note that locatives in combination of verbs function as goal/result markers in those varieties that tend to spell out markers of functional elements, frequently generating a repetition (doubling of the same feature. Finally, I compare Romance and Germanic constructions, noting that diachronic, grammatical and typological differences (with particular reference to Talmy's distinction between verb-framed languages and satellite languages confirm the independence of Romance verb-locative constructions.

  5. Engineering a Cache-Oblivious Sorting Algorithm

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Fagerberg, Rolf; Vinther, Kristoffer

    2007-01-01

    This paper is an algorithmic engineering study of cache-oblivious sorting. We investigate by empirical methods a number of implementation issues and parameter choices for the cache-oblivious sorting algorithm Lazy Funnelsort, and compare the final algorithm with Quicksort, the established standard...

  6. The dCache scientific storage cloud

    CERN Multimedia

    CERN. Geneva

    2014-01-01

    For over a decade, the dCache team has provided software for handling big data for a diverse community of scientists. The team has also amassed a wealth of operational experience from using this software in production. With this experience, the team have refined dCache with the goal of providing a "scientific cloud": a storage solution that satisfies all requirements of a user community by exposing different facets of dCache with which users interact. Recent development, as part of this "scientific cloud" vision, has introduced a new facet: a sync-and-share service, often referred to as "dropbox-like storage". This work has been strongly focused on local requirements, but will be made available in future releases of dCache allowing others to adopt dCache solutions. In this presentation we will outline the current status of the work: both the successes and limitations, and the direction and time-scale of future work.

  7. Efficient Mobile Client Caching Supporting Transaction Semantics

    Directory of Open Access Journals (Sweden)

    IlYoung Chung

    2000-05-01

    Full Text Available In mobile client-server database systems, caching of frequently accessed data is an important technique that will reduce the contention on the narrow bandwidth wireless channel. As the server in mobile environments may not have any information about the state of its clients' cache(stateless server, using broadcasting approach to transmit the updated data lists to numerous concurrent mobile clients is an attractive approach. In this paper, a caching policy is proposed to maintain cache consistency for mobile computers. The proposed protocol adopts asynchronous(non-periodic broadcasting as the cache invalidation scheme, and supports transaction semantics in mobile environments. With the asynchronous broadcasting approach, the proposed protocol can improve the throughput by reducing the abortion of transactions with low communication costs. We study the performance of the protocol by means of simulation experiments.

  8. Archeological Excavations at the Wanapum Cache Site

    International Nuclear Information System (INIS)

    T. E. Marceau

    2000-01-01

    This report was prepared to document the actions taken to locate and excavate an abandoned Wanapum cache located east of the 100-H Reactor area. Evidence (i.e., glass, ceramics, metal, and wood) obtained from shovel and backhoe excavations at the Wanapum cache site indicate that the storage caches were found. The highly fragmented condition of these materials argues that the contents of the caches were collected or destroyed prior to the caches being burned and buried by mechanical equipment. While the fiber nets would have been destroyed by fire, the specialized stone weights would have remained behind. The fact that the site might have been gleaned of desirable artifacts prior to its demolition is consistent with the account by Riddell (1948) for a contemporary village site. Unfortunately, fishing equipment, owned by and used on behalf of the village, that might have returned to productive use has been irretrievably lost

  9. MonetDB/X100 - A DBMS in the CPU cache

    NARCIS (Netherlands)

    M. Zukowski (Marcin); P.A. Boncz (Peter); N.J. Nes (Niels); S. Héman (Sándor)

    2005-01-01

    textabstractX100 is a new execution engine for the MonetDB system, that improves execution speed and overcomes its main memory limitation. It introduces the concept of in-cache vectorized processing that strikes a balance between the existing column-at-a-time MIL execution primitives of MonetDB and

  10. A Distributed Cache Update Deployment Strategy in CDN

    Science.gov (United States)

    E, Xinhua; Zhu, Binjie

    2018-04-01

    The CDN management system distributes content objects to the edge of the internet to achieve the user's near access. Cache strategy is an important problem in network content distribution. A cache strategy was designed in which the content effective diffusion in the cache group, so more content was storage in the cache, and it improved the group hit rate.

  11. WATCHMAN: A Data Warehouse Intelligent Cache Manager

    Science.gov (United States)

    Scheuermann, Peter; Shim, Junho; Vingralek, Radek

    1996-01-01

    Data warehouses store large volumes of data which are used frequently by decision support applications. Such applications involve complex queries. Query performance in such an environment is critical because decision support applications often require interactive query response time. Because data warehouses are updated infrequently, it becomes possible to improve query performance by caching sets retrieved by queries in addition to query execution plans. In this paper we report on the design of an intelligent cache manager for sets retrieved by queries called WATCHMAN, which is particularly well suited for data warehousing environment. Our cache manager employs two novel, complementary algorithms for cache replacement and for cache admission. WATCHMAN aims at minimizing query response time and its cache replacement policy swaps out entire retrieved sets of queries instead of individual pages. The cache replacement and admission algorithms make use of a profit metric, which considers for each retrieved set its average rate of reference, its size, and execution cost of the associated query. We report on a performance evaluation based on the TPC-D and Set Query benchmarks. These experiments show that WATCHMAN achieves a substantial performance improvement in a decision support environment when compared to a traditional LRU replacement algorithm.

  12. Elements of episodic-like memory in animals.

    Science.gov (United States)

    Clayton, N S; Griffiths, D P; Emery, N J; Dickinson, A

    2001-09-29

    A number of psychologists have suggested that episodic memory is a uniquely human phenomenon and, until recently, there was little evidence that animals could recall a unique past experience and respond appropriately. Experiments on food-caching memory in scrub jays question this assumption. On the basis of a single caching episode, scrub jays can remember when and where they cached a variety of foods that differ in the rate at which they degrade, in a way that is inexplicable by relative familiarity. They can update their memory of the contents of a cache depending on whether or not they have emptied the cache site, and can also remember where another bird has hidden caches, suggesting that they encode rich representations of the caching event. They make temporal generalizations about when perishable items should degrade and also remember the relative time since caching when the same food is cached in distinct sites at different times. These results show that jays form integrated memories for the location, content and time of caching. This memory capability fulfils Tulving's behavioural criteria for episodic memory and is thus termed 'episodic-like'. We suggest that several features of episodic memory may not be unique to humans.

  13. Truth Space Method for Caching Database Queries

    Directory of Open Access Journals (Sweden)

    S. V. Mosin

    2015-01-01

    Full Text Available We propose a new method of client-side data caching for relational databases with a central server and distant clients. Data are loaded into the client cache based on queries executed on the server. Every query has the corresponding DB table – the result of the query execution. These queries have a special form called "universal relational query" based on three fundamental Relational Algebra operations: selection, projection and natural join. We have to mention that such a form is the closest one to the natural language and the majority of database search queries can be expressed in this way. Besides, this form allows us to analyze query correctness by checking lossless join property. A subsequent query may be executed in a client’s local cache if we can determine that the query result is entirely contained in the cache. For this we compare truth spaces of the logical restrictions in a new user’s query and the results of the queries execution in the cache. Such a comparison can be performed analytically , without need in additional Database queries. This method may be used to define lacking data in the cache and execute the query on the server only for these data. To do this the analytical approach is also used, what distinguishes our paper from the existing technologies. We propose four theorems for testing the required conditions. The first and the third theorems conditions allow us to define the existence of required data in cache. The second and the fourth theorems state conditions to execute queries with cache only. The problem of cache data actualizations is not discussed in this paper. However, it can be solved by cataloging queries on the server and their serving by triggers in background mode. The article is published in the author’s wording.

  14. Cache management of tape files in mass storage system

    International Nuclear Information System (INIS)

    Cheng Yaodong; Ma Nan; Yu Chuansong; Chen Gang

    2006-01-01

    This paper proposes the group-cooperative caching policy according to the characteristics of tapes and requirements of high energy physics domain. This policy integrates the advantages of traditional local caching and cooperative caching on basis of cache model. It divides cache into independent groups; the same group of cache is made of cooperating disks on network. This paper also analyzes the directory management, update algorithm and cache consistency of the policy. The experiment shows the policy can meet the requirements of data processing and mass storage in high energy physics domain very well. (authors)

  15. Optimizing Maintenance of Constraint-Based Database Caches

    Science.gov (United States)

    Klein, Joachim; Braun, Susanne

    Caching data reduces user-perceived latency and often enhances availability in case of server crashes or network failures. DB caching aims at local processing of declarative queries in a DBMS-managed cache close to the application. Query evaluation must produce the same results as if done at the remote database backend, which implies that all data records needed to process such a query must be present and controlled by the cache, i. e., to achieve “predicate-specific” loading and unloading of such record sets. Hence, cache maintenance must be based on cache constraints such that “predicate completeness” of the caching units currently present can be guaranteed at any point in time. We explore how cache groups can be maintained to provide the data currently needed. Moreover, we design and optimize loading and unloading algorithms for sets of records keeping the caching units complete, before we empirically identify the costs involved in cache maintenance.

  16. An Improved Algorithm Research on the PrefixSpan Based on the Server Session Constraint

    Directory of Open Access Journals (Sweden)

    Cai Hong-Guo

    2017-01-01

    Full Text Available When we mine long sequential pattern and discover knowledge by the PrefixSpan algorithm in Web Usage Mining (WUM.The elements and the suffix sequences are much more may cause the problem of the calculation, such as the space explosion. To further solve the problem a more effective way is that. Firstly, a server session-based server log file format is proposed. Then the improved algorithm on the PrefixSpan based on server session constraint is discussed for mining frequent Sequential patterns on the website. Finally, the validity and superiority of the method are presented by the experiment in the paper.

  17. Cache Aided Decode-and-Forward Relaying Networks: From the Spatial View

    Directory of Open Access Journals (Sweden)

    Junjuan Xia

    2018-01-01

    Full Text Available We investigate cache technique from the spatial view and study its impact on the relaying networks. In particular, we consider a dual-hop relaying network, where decode-and-forward (DF relays can assist the data transmission from the source to the destination. In addition to the traditional dual-hop relaying, we also consider the cache from the spatial view, where the source can prestore the data among the memories of the nodes around the destination. For the DF relaying networks without and with cache, we study the system performance by deriving the analytical expressions of outage probability and symbol error rate (SER. We also derive the asymptotic outage probability and SER in the high regime of transmit power, from which we find the system diversity order can be rapidly increased by using cache and the system performance can be significantly improved. Simulation and numerical results are demonstrated to verify the proposed studies and find that the system power resources can be efficiently saved by using cache technique.

  18. The influence of non-linguistic factors on the usage of the pre-prefix in Bantu

    DEFF Research Database (Denmark)

    Kühl, Karoline; Petzell, Malin

    2017-01-01

    and social factors, taking into account the situation of intense language contact between Luguru and the dominating language Swahili, where the pre-prefix is non-existent. Not much has been published on Luguru overall, and this is the first study of the pre-prefix. Moreover, it is, to our knowledge...

  19. Emptiness is not so empty: The meaning of the Russian prefix вы- in the natural perfective verbs

    Directory of Open Access Journals (Sweden)

    Tatiana Pozolotina

    2009-01-01

    Full Text Available This paper analyzes the meaning of the so-called "empty" prefix вы- (‘out-' of natural perfective verbs in the Russian language. It is argued that the prefix is not semantically empty, but displays meanings that can be analyzed as a radial category.

  20. Medical Terminology: Using Some Common Prefixes, Suffixes, and Roots. Health Occupations Education Module.

    Science.gov (United States)

    Temple Univ., Philadelphia, PA. Div. of Vocational Education.

    This module on medical terminology (using common prefixes, suffixes, and root words) is one of 17 modules designed for individualized instruction in health occupations education programs at both the secondary and postsecondary levels. This module consists of an introduction to the module topic, a list of resources needed, and three learning…

  1. Using Max-Plus Algebra for the Evaluation of Stochastic Process Algebra Prefixes

    NARCIS (Netherlands)

    Cloth, L.; de Alfaro, L.; Gilmore, S.; Bohnenkamp, H.C.; Haverkort, Boudewijn R.H.M.

    2001-01-01

    In this paper, the concept of complete finite prefixes for process algebra expressions is extended to stochastic models. Events are supposed to happen after a delay that is determined by random variables assigned to the preceding conditions. Max-plus algebra expressions are shown to provide an

  2. dCache, agile adoption of storage technology

    Energy Technology Data Exchange (ETDEWEB)

    Millar, A. P. [Hamburg U.; Baranova, T. [Hamburg U.; Behrmann, G. [Unlisted, DK; Bernardt, C. [Hamburg U.; Fuhrmann, P. [Hamburg U.; Litvintsev, D. O. [Fermilab; Mkrtchyan, T. [Hamburg U.; Petersen, A. [Hamburg U.; Rossi, A. [Fermilab; Schwank, K. [Hamburg U.

    2012-01-01

    For over a decade, dCache has been synonymous with large-capacity, fault-tolerant storage using commodity hardware that supports seamless data migration to and from tape. In this paper we provide some recent news of changes within dCache and the community surrounding it. We describe the flexible nature of dCache that allows both externally developed enhancements to dCache facilities and the adoption of new technologies. Finally, we present information about avenues the dCache team is exploring for possible future improvements in dCache.

  3. Cache-aware data structure model for parallelism and dynamic load balancing

    International Nuclear Information System (INIS)

    Sridi, Marwa

    2016-01-01

    This PhD thesis is dedicated to the implementation of innovative parallel methods in the framework of fast transient fluid-structure dynamics. It improves existing methods within EUROPLEXUS software, in order to optimize the shared memory parallel strategy, complementary to the original distributed memory approach, brought together into a global hybrid strategy for clusters of multi-core nodes. Starting from a sound analysis of the state of the art concerning data structuring techniques correlated to the hierarchic memory organization of current multi-processor architectures, the proposed work introduces an approach suitable for an explicit time integration (i.e. with no linear system to solve at each step). A data structure of type 'Structure of arrays' is conserved for the global data storage, providing flexibility and efficiency for current operations on kinematics fields (displacement, velocity and acceleration). On the contrary, in the particular case of elementary operations (for internal forces generic computations, as well as fluxes computations between cell faces for fluid models), particularly time consuming but localized in the program, a temporary data structure of type 'Array of structures' is used instead, to force an efficient filling of the cache memory and increase the performance of the resolution, for both serial and shared memory parallel processing. Switching from the global structure to the temporary one is based on a cell grouping strategy, following classing cache-blocking principles but handling specifically for this work neighboring data necessary to the efficient treatment of ALE fluxes for cells on the group boundaries. The proposed approach is extensively tested, from the point of views of both the computation time and the access failures into cache memory, confronting the gains obtained within the elementary operations to the potential overhead generated by the data structure switch. Obtained results are very satisfactory, especially

  4. Elements of episodic-like memory in animals.

    OpenAIRE

    Clayton, N S; Griffiths, D P; Emery, N J; Dickinson, A

    2001-01-01

    A number of psychologists have suggested that episodic memory is a uniquely human phenomenon and, until recently, there was little evidence that animals could recall a unique past experience and respond appropriately. Experiments on food-caching memory in scrub jays question this assumption. On the basis of a single caching episode, scrub jays can remember when and where they cached a variety of foods that differ in the rate at which they degrade, in a way that is inexplicable by relative fam...

  5. EqualChance: Addressing Intra-set Write Variation to Increase Lifetime of Non-volatile Caches

    Energy Technology Data Exchange (ETDEWEB)

    Mittal, Sparsh [ORNL; Vetter, Jeffrey S [ORNL

    2014-01-01

    To address the limitations of SRAM such as high-leakage and low-density, researchers have explored use of non-volatile memory (NVM) devices, such as ReRAM (resistive RAM) and STT-RAM (spin transfer torque RAM) for designing on-chip caches. A crucial limitation of NVMs, however, is that their write endurance is low and the large intra-set write variation introduced by existing cache management policies may further exacerbate this problem, thereby reducing the cache lifetime significantly. We present EqualChance, a technique to increase cache lifetime by reducing intra-set write variation. EqualChance works by periodically changing the physical cache-block location of a write-intensive data item within a set to achieve wear-leveling. Simulations using workloads from SPEC CPU2006 suite and HPC (high-performance computing) field show that EqualChance improves the cache lifetime by 4.29X. Also, its implementation overhead is small, and it incurs very small performance and energy loss.

  6. Cache-aware network-on-chip for chip multiprocessors

    Science.gov (United States)

    Tatas, Konstantinos; Kyriacou, Costas; Dekoulis, George; Demetriou, Demetris; Avraam, Costas; Christou, Anastasia

    2009-05-01

    This paper presents the hardware prototype of a Network-on-Chip (NoC) for a chip multiprocessor that provides support for cache coherence, cache prefetching and cache-aware thread scheduling. A NoC with support to these cache related mechanisms can assist in improving systems performance by reducing the cache miss ratio. The presented multi-core system employs the Data-Driven Multithreading (DDM) model of execution. In DDM thread scheduling is done according to data availability, thus the system is aware of the threads to be executed in the near future. This characteristic of the DDM model allows for cache aware thread scheduling and cache prefetching. The NoC prototype is a crossbar switch with output buffering that can support a cache-aware 4-node chip multiprocessor. The prototype is built on the Xilinx ML506 board equipped with a Xilinx Virtex-5 FPGA.

  7. Cache timing attacks on recent microarchitectures

    DEFF Research Database (Denmark)

    Andreou, Alexandres; Bogdanov, Andrey; Tischhauser, Elmar Wolfgang

    2017-01-01

    Cache timing attacks have been known for a long time, however since the rise of cloud computing and shared hardware resources, such attacks found new potentially devastating applications. One prominent example is S$A (presented by Irazoqui et al at S&P 2015) which is a cache timing attack against...... AES or similar algorithms in virtualized environments. This paper applies variants of this cache timing attack to Intel's latest generation of microprocessors. It enables a spy-process to recover cryptographic keys, interacting with the victim processes only over TCP. The threat model is a logically...... separated but CPU co-located attacker with root privileges. We report successful and practically verified applications of this attack against a wide range of microarchitectures, from a two-core Nehalem processor (i5-650) to two-core Haswell (i7-4600M) and four-core Skylake processors (i7-6700). The attack...

  8. CSU Final Report on the Math/CS Institute CACHE: Communication-Avoiding and Communication-Hiding at the Extreme Scale

    Energy Technology Data Exchange (ETDEWEB)

    Strout, Michelle [Colorado State University

    2014-06-10

    The CACHE project entails researching and developing new versions of numerical algorithms that result in data reuse that can be scheduled in a communication avoiding way. Since memory accesses take more time than any computation and require the most power, the focus on turning data reuse into data locality is critical to improving performance and reducing power usage in scientific simulations. This final report summarizes the accomplishments at Colorado State University as part of the CACHE project.

  9. Efficient Context Switching for the Stack Cache: Implementation and Analysis

    DEFF Research Database (Denmark)

    Abbaspourseyedi, Sahar; Brandner, Florian; Naji, Amine

    2015-01-01

    , the analysis of the stack cache was limited to individual tasks, ignoring aspects related to multitasking. A major drawback of the original stack cache design is that, due to its simplicity, it cannot hold the data of multiple tasks at the same time. Consequently, the entire cache content needs to be saved...

  10. Analysis of preemption costs for the stack cache

    DEFF Research Database (Denmark)

    Naji, Amine; Abbaspour, Sahar; Brandner, Florian

    2018-01-01

    , the analysis of the stack cache was limited to individual tasks, ignoring aspects related to multitasking. A major drawback of the original stack cache design is that, due to its simplicity, it cannot hold the data of multiple tasks at the same time. Consequently, the entire cache content needs to be saved...

  11. “RETRO-,” AN EMERGING PREFIX FOR FUTURE TECHNOLOGICAL DEVELOPMENT?

    Directory of Open Access Journals (Sweden)

    Martin A. Hubbe

    2009-02-01

    Full Text Available It is proposed that the prefix “retro” can serve as an irreverent, but timely buzzword for the development of new technology to meet human needs. Society has carried out experiments at a very large scale for the last century or so to meet our collective needs though the use of fossil-based fuels and synthetic materials. Those experiments have seemed successful in the short term, feeding more of us and supplying a lot of us with rising standards of living. But the experiments often have failed us in terms of sustainability. A health crisis, global warming, and resource depletion are urgent problems caused by careless use of fossil fuels and related synthetic organic chemicals. The prefix “retro,” as in “retrotechology,” signals a disciplined return to a reliance on nature-based products, as well as a respect for the beauty, but also the fragile character of our natural environment.

  12. Some remarks on Romanian reflexive verbs derived by the prefix "în"

    Directory of Open Access Journals (Sweden)

    Veronica Tomescu

    2008-01-01

    Full Text Available The paper discusses a small group of Romanian reflexive verbs, denominals derived by means of the prefix în, as well as a group of transitive verbs which are reflexivized. Their behaviour will be briefly considered. A search on the Internet has also been made alongside the dictionary study in order to gain an insight into the frequency of use of certain forms.

  13. A cache-friendly sampling strategy for texture-based volume rendering on GPU

    Directory of Open Access Journals (Sweden)

    Junpeng Wang

    2017-06-01

    Full Text Available The texture-based volume rendering is a memory-intensive algorithm. Its performance relies heavily on the performance of the texture cache. However, most existing texture-based volume rendering methods blindly map computational resources to texture memory and result in incoherent memory access patterns, causing low cache hit rates in certain cases. The distance between samples taken by threads of an atomic scheduling unit (e.g. a warp of 32 threads in CUDA of the GPU is a crucial factor that affects the texture cache performance. Based on this fact, we present a new sampling strategy, called Warp Marching, for the ray-casting algorithm of texture-based volume rendering. The effects of different sample organizations and different thread-pixel mappings in the ray-casting algorithm are thoroughly analyzed. Also, a pipeline manner color blending approach is introduced and the power of warp-level GPU operations is leveraged to improve the efficiency of parallel executions on the GPU. In addition, the rendering performance of the Warp Marching is view-independent, and it outperforms existing empty space skipping techniques in scenarios that need to render large dynamic volumes in a low resolution image. Through a series of micro-benchmarking and real-life data experiments, we rigorously analyze our sampling strategies and demonstrate significant performance enhancements over existing sampling methods.

  14. Design Space Exploration of Object Caches with Cross-Profiling

    DEFF Research Database (Denmark)

    Schoeberl, Martin; Binder, Walter; Villazon, Alex

    2011-01-01

    . However, before implementing such an object cache, an empirical analysis of different organization forms is needed. We use a cross-profiling technique based on aspect-oriented programming in order to evaluate different object cache organizations with standard Java benchmarks. From the evaluation we......To avoid data cache trashing between heap-allocated data and other data areas, a distinct object cache has been proposed for embedded real-time Java processors. This object cache uses high associativity in order to statically track different object pointers for worst-case execution-time analysis...... conclude that field access exhibits some temporal locality, but almost no spatial locality. Therefore, filling long cache lines on a miss just introduces a high miss penalty without increasing the hit rate enough to make up for the increased miss penalty. For an object cache, it is more efficient to fill...

  15. Cache Management of Big Data in Equipment Condition Assessment

    Directory of Open Access Journals (Sweden)

    Ma Yan

    2016-01-01

    Full Text Available Big data platform for equipment condition assessment is built for comprehensive analysis. The platform has various application demands. According to its response time, its application can be divided into offline, interactive and real-time types. For real-time application, its data processing efficiency is important. In general, data cache is one of the most efficient ways to improve query time. However, big data caching is different from the traditional data caching. In the paper we propose a distributed cache management framework of big data for equipment condition assessment. It consists of three parts: cache structure, cache replacement algorithm and cache placement algorithm. Cache structure is the basis of the latter two algorithms. Based on the framework and algorithms, we make full use of the characteristics of just accessing some valuable data during a period of time, and put relevant data on the neighborhood nodes, which largely reduce network transmission cost. We also validate the performance of our proposed approaches through extensive experiments. It demonstrates that the proposed cache replacement algorithm and cache management framework has higher hit rate or lower query time than LRU algorithm and round-robin algorithm.

  16. EFFICIENCY OF MULTI-MODULE SOLAR COLLECTORS AS A PREFIX TO A BOILER

    Directory of Open Access Journals (Sweden)

    Denysova A.E.

    2014-12-01

    Full Text Available Influencing factors on thermal and economic efficiency of the combined of heat supply installation are established. Constructive circuits of solar heat supply "prefix" interaction with boiler installation are worked out. Mathematical models of heat exchange processes in elements of combined heat supply system with the account solar engineering characteristics are developed. The techniques of analysis of efficiency of multi-modular system of solar collectors with compulsory circulation for water heating boiler allowing calculating of efficiency factor; heat removal factor and heat transfer factor with the account of construction and operation conditions of alternative heat supply system are presented.

  17. OPTIMAL DATA REPLACEMENT TECHNIQUE FOR COOPERATIVE CACHING IN MANET

    Directory of Open Access Journals (Sweden)

    P. Kuppusamy

    2014-09-01

    Full Text Available A cooperative caching approach improves data accessibility and reduces query latency in Mobile Ad hoc Network (MANET. Maintaining the cache is challenging issue in large MANET due to mobility, cache size and power. The previous research works on caching primarily have dealt with LRU, LFU and LRU-MIN cache replacement algorithms that offered low query latency and greater data accessibility in sparse MANET. This paper proposes Memetic Algorithm (MA to locate the better replaceable data based on neighbours interest and fitness value of cached data to store the newly arrived data. This work also elects ideal CH using Meta heuristic search Ant Colony Optimization algorithm. The simulation results shown that proposed algorithm reduces the latency, control overhead and increases the packet delivery rate than existing approach by increasing nodes and speed respectively.

  18. Enhancing Leakage Power in CPU Cache Using Inverted Architecture

    OpenAIRE

    Bilal A. Shehada; Ahmed M. Serdah; Aiman Abu Samra

    2013-01-01

    Power consumption is an increasingly pressing problem in modern processor design. Since the on-chip caches usually consume a significant amount of power so power and energy consumption parameters have become one of the most important design constraint. It is one of the most attractive targets for power reduction. This paper presents an approach to enhance the dynamic power consumption of CPU cache using inverted cache architecture. Our assumption tries to reduce dynamic write power dissipatio...

  19. Anatomical study of prefixed versus postfixed brachial plexuses in adult human cadaver.

    Science.gov (United States)

    Guday, Edengenet; Bekele, Asegedech; Muche, Abebe

    2017-05-01

    The brachial plexus is usually formed by the fusion of anterior primary rami of the fifth to eighth cervical and the first thoracic spinal nerves. Variations in the formation of the brachial plexus may occur. Variations in brachial plexus anatomy are important to radiologists, surgeons and anaesthesiologists performing surgical procedures in the neck, axilla and upper limb regions. These variations may lead to deviation from the expected dermatome distribution as well as differences in the motor innervation of muscles of the upper limb. This study is aimed to describe the anatomical variations of brachial plexus in its formation among 20 Ethiopian cadavers. Observational based study was conducted by using 20 cadavers obtained from the Department of Human Anatomy at University of Gondar, Bahir Dar, Addis Ababa, Hawasa, Hayat Medical College and St Paul Hospital Millennium Medical College. Data analysis was conducted using thematic approaches. A total of 20 cadavers examined bilaterally for the formation of brachial plexus. Of the 40 sides, 30 sides (75%) were found normal, seven sides (17.5%) prefixed, three sides (7.5%) postfixed and one side of the cadaver lacks cord formation. The brachial plexus formation in most subjects is found to be normal. Among the variants, the numbers of the prefixed brachial plexuses are greater than the postfixed brachial plexuses. © 2016 Royal Australasian College of Surgeons.

  20. Instant Varnish Cache how-to

    CERN Document Server

    Moutinho, Roberto

    2013-01-01

    Filled with practical, step-by-step instructions and clear explanations for the most important and useful tasks. Get the job done and learn as you go. Easy-to-follow, step-by-step recipes which will get you started with Varnish Cache. Practical examples will help you to get set up quickly and easily.This book is aimed at system administrators and web developers who need to scale websites without tossing money on a large and costly infrastructure. It's assumed that you have some knowledge of the HTTP protocol, how browsers and server communicate with each other, and basic Linux systems.

  1. A Stack Cache for Real-Time Systems

    DEFF Research Database (Denmark)

    Schoeberl, Martin; Nielsen, Carsten

    2016-01-01

    Real-time systems need time-predictable computing platforms to allowfor static analysis of the worst-case execution time. Caches are important for good performance, but data caches arehard to analyze for the worst-case execution time. Stack allocated data has different properties related...

  2. On Optimal Geographical Caching in Heterogeneous Cellular Networks

    NARCIS (Netherlands)

    Serbetci, Berksan; Goseling, Jasper

    2017-01-01

    In this work we investigate optimal geographical caching in heterogeneous cellular networks where different types of base stations (BSs) have different cache capacities. Users request files from a content library according to a known probability distribution. The performance metric is the total hit

  3. Memory

    Science.gov (United States)

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

  4. Version pressure feedback mechanisms for speculative versioning caches

    Science.gov (United States)

    Eichenberger, Alexandre E.; Gara, Alan; O& #x27; Brien, Kathryn M.; Ohmacht, Martin; Zhuang, Xiaotong

    2013-03-12

    Mechanisms are provided for controlling version pressure on a speculative versioning cache. Raw version pressure data is collected based on one or more threads accessing cache lines of the speculative versioning cache. One or more statistical measures of version pressure are generated based on the collected raw version pressure data. A determination is made as to whether one or more modifications to an operation of a data processing system are to be performed based on the one or more statistical measures of version pressure, the one or more modifications affecting version pressure exerted on the speculative versioning cache. An operation of the data processing system is modified based on the one or more determined modifications, in response to a determination that one or more modifications to the operation of the data processing system are to be performed, to affect the version pressure exerted on the speculative versioning cache.

  5. Study of cache performance in distributed environment for data processing

    International Nuclear Information System (INIS)

    Makatun, Dzmitry; Lauret, Jérôme; Šumbera, Michal

    2014-01-01

    Processing data in distributed environment has found its application in many fields of science (Nuclear and Particle Physics (NPP), astronomy, biology to name only those). Efficiently transferring data between sites is an essential part of such processing. The implementation of caching strategies in data transfer software and tools, such as the Reasoner for Intelligent File Transfer (RIFT) being developed in the STAR collaboration, can significantly decrease network load and waiting time by reusing the knowledge of data provenance as well as data placed in transfer cache to further expand on the availability of sources for files and data-sets. Though, a great variety of caching algorithms is known, a study is needed to evaluate which one can deliver the best performance in data access considering the realistic demand patterns. Records of access to the complete data-sets of NPP experiments were analyzed and used as input for computer simulations. Series of simulations were done in order to estimate the possible cache hits and cache hits per byte for known caching algorithms. The simulations were done for cache of different sizes within interval 0.001 – 90% of complete data-set and low-watermark within 0-90%. Records of data access were taken from several experiments and within different time intervals in order to validate the results. In this paper, we will discuss the different data caching strategies from canonical algorithms to hybrid cache strategies, present the results of our simulations for the diverse algorithms, debate and identify the choice for the best algorithm in the context of Physics Data analysis in NPP. While the results of those studies have been implemented in RIFT, they can also be used when setting up cache in any other computational work-flow (Cloud processing for example) or managing data storages with partial replicas of the entire data-set

  6. Planetary Sample Caching System Design Options

    Science.gov (United States)

    Collins, Curtis; Younse, Paulo; Backes, Paul

    2009-01-01

    Potential Mars Sample Return missions would aspire to collect small core and regolith samples using a rover with a sample acquisition tool and sample caching system. Samples would need to be stored in individual sealed tubes in a canister that could be transfered to a Mars ascent vehicle and returned to Earth. A sample handling, encapsulation and containerization system (SHEC) has been developed as part of an integrated system for acquiring and storing core samples for application to future potential MSR and other potential sample return missions. Requirements and design options for the SHEC system were studied and a recommended design concept developed. Two families of solutions were explored: 1)transfer of a raw sample from the tool to the SHEC subsystem and 2)transfer of a tube containing the sample to the SHEC subsystem. The recommended design utilizes sample tool bit change out as the mechanism for transferring tubes to and samples in tubes from the tool. The SHEC subsystem design, called the Bit Changeout Caching(BiCC) design, is intended for operations on a MER class rover.

  7. Contrastive Analysis between English and Indonesian Prefixes and Suffixes (A Narative Text Analysis of Legends in Perspective of Morphology)

    Science.gov (United States)

    Pauzan

    2016-01-01

    This research deals with finding the similarities and differences, and describing the types of the English and Indonesian prefixes and suffixes for the narrative text of Legends. In this research, writer used descriptive qualitative research and contrastive methodology to find out the valid data. After investigating the data, writer found some…

  8. Historical Perspectives on Ancient Greek Derived "a" Prefixed Nomenclature for Acquired Neurocognitive Impairment.

    Science.gov (United States)

    Gasquoine, Philip Gerard

    2017-06-01

    Distinct forms of acquired neurocognitive impairment are often described by "a" prefixed terms that derive from ancient Greek (and in one case Latin). Two modern English language neurological and neuropsychological reference books were searched to identify 17 such terms in contemporary usage: amnesia, akinesia, ataxia, aphasia, agraphia, anosmia, apraxia, athetosis, ageusia, achromatopsia, agnosia, alexia, amusia, anomia, anarthria, anosognosia, and acalculia. These were traced to their initial association with acquired neurocognitive impairment in German, English, and French language medical publications from the late 18th, 19th, and early 20th centuries (1770 through 1920). Some of these terms (e.g., agnosia) were used in ancient Greek, although not associated with neurocognitive impairment. The remainder constitute novel semantically plausible (e.g., anosmia) and unclear (e.g., alexia) formulations. In the localizationist thinking of the time, neurocognition was conceived as being organized within specialized "centers" in specific locations connected by pathways within the brain.

  9. Behavior characterization of the shared last-level cache in a chip multiprocessor

    OpenAIRE

    Benedicte Illescas, Pedro

    2014-01-01

    [CATALÀ] Aquest projecte consisteix a analitzar diferents aspectes de la jerarquia de memòria i entendre la seva influència al rendiment del sistema. Els aspectes que s'analitzaran són els algorismes de reemplaçament, els esquemes de mapeig de memòria i les polítiques de pàgina de memòria. [ANGLÈS] This project consists in analyzing different aspects of the memory hierarchy and understanding its influence in the overall system performance. The aspects that will be analyzed are cache replac...

  10. Improving the Performance and Energy Efficiency of Phase Change Memory Systems

    Institute of Scientific and Technical Information of China (English)

    王琪; 李佳芮; 王东辉

    2015-01-01

    Phase change memory (PCM) is a promising technology for future memory thanks to its better scalability and lower leakage power than DRAM (dynamic random-access memory). However, adopting PCM as main memory needs to overcome its write issues, such as long write latency and high write power. In this paper, we propose two techniques to improve the performance and energy-efficiency of PCM memory systems. First, we propose a victim cache technique utilizing the existing buffer in the memory controller to reduce PCM memory accesses. The key idea is reorganizing the buffer into a victim cache structure (RBC) to provide additional hits for the LLC (last level cache). Second, we propose a chip parallelism-aware replacement policy (CPAR) for the victim cache to further improve performance. Instead of evicting one cache line once, CPAR evicts multiple cache lines that access different PCM chips. CPAR can reduce the frequent victim cache eviction and improve the write parallelism of PCM chips. The evaluation results show that, compared with the baseline, RBC can improve PCM memory system performance by up to 9.4% and 5.4% on average. Combing CPAR with RBC (RBC+CPAR) can improve performance by up to 19.0% and 12.1% on average. Moreover, RBC and RBC+CPAR can reduce memory energy consumption by 8.3%and 6.6%on average, respectively.

  11. A Two-Level Cache for Distributed Information Retrieval in Search Engines

    Directory of Open Access Journals (Sweden)

    Weizhe Zhang

    2013-01-01

    Full Text Available To improve the performance of distributed information retrieval in search engines, we propose a two-level cache structure based on the queries of the users’ logs. We extract the highest rank queries of users from the static cache, in which the queries are the most popular. We adopt the dynamic cache as an auxiliary to optimize the distribution of the cache data. We propose a distribution strategy of the cache data. The experiments prove that the hit rate, the efficiency, and the time consumption of the two-level cache have advantages compared with other structures of cache.

  12. A two-level cache for distributed information retrieval in search engines.

    Science.gov (United States)

    Zhang, Weizhe; He, Hui; Ye, Jianwei

    2013-01-01

    To improve the performance of distributed information retrieval in search engines, we propose a two-level cache structure based on the queries of the users' logs. We extract the highest rank queries of users from the static cache, in which the queries are the most popular. We adopt the dynamic cache as an auxiliary to optimize the distribution of the cache data. We propose a distribution strategy of the cache data. The experiments prove that the hit rate, the efficiency, and the time consumption of the two-level cache have advantages compared with other structures of cache.

  13. Replication Strategy for Spatiotemporal Data Based on Distributed Caching System.

    Science.gov (United States)

    Xiong, Lian; Yang, Liu; Tao, Yang; Xu, Juan; Zhao, Lun

    2018-01-14

    The replica strategy in distributed cache can effectively reduce user access delay and improve system performance. However, developing a replica strategy suitable for varied application scenarios is still quite challenging, owing to differences in user access behavior and preferences. In this paper, a replication strategy for spatiotemporal data (RSSD) based on a distributed caching system is proposed. By taking advantage of the spatiotemporal locality and correlation of user access, RSSD mines high popularity and associated files from historical user access information, and then generates replicas and selects appropriate cache node for placement. Experimental results show that the RSSD algorithm is simple and efficient, and succeeds in significantly reducing user access delay.

  14. Método y sistema de modelado de memoria cache

    OpenAIRE

    Posadas Cobo, Héctor; Villar Bonet, Eugenio; Díaz Suárez, Luis

    2010-01-01

    Un método de modelado de una memoria cache de datos de un procesador destino, para simular el comportamiento de dicha memoria cache de datos en la ejecución de un código software en una plataforma que comprenda dicho procesador destino, donde dicha simulación se realiza en una plataforma nativa que tiene un procesador diferente del procesador destino que comprende dicha memoria cache de datos que se va a modelar, donde dicho modelado se realiza mediante la ejecución en dicha plataforma nativa...

  15. A distributed storage system with dCache

    DEFF Research Database (Denmark)

    Behrmann, Gerd; Fuhrmann, Patrick; Grønager, Michael

    2008-01-01

    The LCG collaboration is encompassed by a number of Tier 1 centers. The Nordic LCG Tier 1, operated by NDGF, is in contrast to many other Tier 1 centers distributed over the Nordic countries. A distributed setup was chosen for both political and technical reasons, but also provides a number...... of unique challenges. dCache is well known and respected as a powerful distributed storage resource manager, and was chosen for implementing the storage aspects of the Nordic Tier 1. In contrast to classic dCache deployments, we deploy dCache over a WAN with limited bandwidth, high latency, frequent network...

  16. Randomized Caches Considered Harmful in Hard Real-Time Systems

    Directory of Open Access Journals (Sweden)

    Jan Reineke

    2014-06-01

    Full Text Available We investigate the suitability of caches with randomized placement and replacement in the context of hard real-time systems. Such caches have been claimed to drastically reduce the amount of information required by static worst-case execution time (WCET analysis, and to be an enabler for measurement-based probabilistic timing analysis. We refute these claims and conclude that with prevailing static and measurement-based analysis techniques caches with deterministic placement and least-recently-used replacement are preferable over randomized ones.

  17. Replication Strategy for Spatiotemporal Data Based on Distributed Caching System

    Science.gov (United States)

    Xiong, Lian; Tao, Yang; Xu, Juan; Zhao, Lun

    2018-01-01

    The replica strategy in distributed cache can effectively reduce user access delay and improve system performance. However, developing a replica strategy suitable for varied application scenarios is still quite challenging, owing to differences in user access behavior and preferences. In this paper, a replication strategy for spatiotemporal data (RSSD) based on a distributed caching system is proposed. By taking advantage of the spatiotemporal locality and correlation of user access, RSSD mines high popularity and associated files from historical user access information, and then generates replicas and selects appropriate cache node for placement. Experimental results show that the RSSD algorithm is simple and efficient, and succeeds in significantly reducing user access delay. PMID:29342897

  18. A Novel Cache Invalidation Scheme for Mobile Networks

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In this paper, we propose a strategy of maintaining cache consistency in wireless mobile environments, which adds a validation server (VS) into the GPRS network, utilizes the location information of mobile terminal in SGSN located at GPRS backbone, just sends invalidation information to mobile terminal which is online in accordance with the cached data, and reduces the information amount in asynchronous transmission. This strategy enables mobile terminal to access cached data with very little computing amount, little delay and arbitrary disconnection intervals, and excels the synchronous IR and asynchronous state (AS) in the total performances.

  19. A Shared Scratchpad Memory with Synchronization Support

    DEFF Research Database (Denmark)

    Hansen, Henrik Enggaard; Maroun, Emad Jacob; Kristensen, Andreas Toftegaard

    2017-01-01

    Multicore processors usually communicate via shared memory, which is backed up by a shared level 2 cache and a cache coherence protocol. However, this solution is not a good fit for real-time systems, where we need to provide tight guarantees on execution and memory access times. In this paper, we...... propose a shared scratchpad memory as a time-predictable communication and synchronization structure, instead of the level 2 cache. The shared on-chip memory is accessed via a time division multiplexing arbiter, isolating the execution time of load and store instructions between processing cores....... Furthermore, the arbiter supports an extended time slot where an atomic load and store instruction can be executed to implement synchronization primitives. In the evaluation we show that a shared scratchpad memory is an efficient communication structure for a small number of processors; in our setup, 9 cores...

  20. A Comparison between Fixed Priority and EDF Scheduling accounting for Cache Related Pre-emption Delays

    Directory of Open Access Journals (Sweden)

    Will Lunniss

    2014-04-01

    Full Text Available In multitasking real-time systems, the choice of scheduling algorithm is an important factor to ensure that response time requirements are met while maximising limited system resources. Two popular scheduling algorithms include fixed priority (FP and earliest deadline first (EDF. While they have been studied in great detail before, they have not been compared when taking into account cache related pre-emption delays (CRPD. Memory and cache are split into a number of blocks containing instructions and data. During a pre-emption, cache blocks from the pre-empting task can evict those of the pre-empted task. When the pre-empted task is resumed, if it then has to re-load the evicted blocks, CRPD are introduced which then affect the schedulability of the task. In this paper we compare FP and EDF scheduling algorithms in the presence of CRPD using the state-of-the-art CRPD analysis. We find that when CRPD is accounted for, the performance gains offered by EDF over FP, while still notable, are diminished. Furthermore, we find that under scenarios that cause relatively high CRPD, task layout optimisation techniques can be applied to allow FP to schedule tasksets at a similar processor utilisation to EDF. Thus making the choice of the task layout in memory as important as the choice of scheduling algorithm. This is very relevant for industry, as it is much cheaper and simpler to adjust the task layout through the linker than it is to switch the scheduling algorithm.

  1. Distributed caching mechanism for various MPE software services

    CERN Document Server

    Svec, Andrej

    2017-01-01

    The MPE Software Section provides multiple software services to facilitate the testing and the operation of the CERN Accelerator complex. Continuous growth in the number of users and the amount of processed data result in the requirement of high scalability. Our current priority is to move towards a distributed and properly load balanced set of services based on containers. The aim of this project is to implement the generic caching mechanism applicable to our services and chosen architecture. The project will at first require research about the different aspects of distributed caching (persistence, no gc-caching, cache consistency etc.) and the available technologies followed by the implementation of the chosen solution. In order to validate the correctness and performance of the implementation in the last phase of the project it will be required to implement a monitoring layer and integrate it with the current ELK stack.

  2. Dynamic Video Streaming in Caching-enabled Wireless Mobile Networks

    OpenAIRE

    Liang, C.; Hu, S.

    2017-01-01

    Recent advances in software-defined mobile networks (SDMNs), in-network caching, and mobile edge computing (MEC) can have great effects on video services in next generation mobile networks. In this paper, we jointly consider SDMNs, in-network caching, and MEC to enhance the video service in next generation mobile networks. With the objective of maximizing the mean measurement of video quality, an optimization problem is formulated. Due to the coupling of video data rate, computing resource, a...

  3. Probabilistic Caching Placement in the Presence of Multiple Eavesdroppers

    Directory of Open Access Journals (Sweden)

    Fang Shi

    2018-01-01

    Full Text Available The wireless caching has attracted a lot of attention in recent years, since it can reduce the backhaul cost significantly and improve the user-perceived experience. The existing works on the wireless caching and transmission mainly focus on the communication scenarios without eavesdroppers. When the eavesdroppers appear, it is of vital importance to investigate the physical-layer security for the wireless caching aided networks. In this paper, a caching network is studied in the presence of multiple eavesdroppers, which can overhear the secure information transmission. We model the locations of eavesdroppers by a homogeneous Poisson Point Process (PPP, and the eavesdroppers jointly receive and decode contents through the maximum ratio combining (MRC reception which yields the worst case of wiretap. Moreover, the main performance metric is measured by the average probability of successful transmission, which is the probability of finding and successfully transmitting all the requested files within a radius R. We study the system secure transmission performance by deriving a single integral result, which is significantly affected by the probability of caching each file. Therefore, we extend to build the optimization problem of the probability of caching each file, in order to optimize the system secure transmission performance. This optimization problem is nonconvex, and we turn to use the genetic algorithm (GA to solve the problem. Finally, simulation and numerical results are provided to validate the proposed studies.

  4. A Compact In-Memory Dictionary for RDF data

    NARCIS (Netherlands)

    Bazoubandi, Hamid R.; de Rooij, Steven; Urbani, Jacopo; ten Teije, Annette; van Harmelen, Frank; Bal, Henri

    2015-01-01

    While almost all dictionary compression techniques focus on static RDF data, we present a compact in-memory RDF dictionary for dynamic and streaming data. To do so, we analysed the structure of terms in real-world datasets and observed a high degree of common prefixes. We studied the applicability

  5. Interference Cancellation Schemes for Single-Carrier Block Transmission with Insufficient Cyclic Prefix

    Directory of Open Access Journals (Sweden)

    Hayashi Kazunori

    2008-01-01

    Full Text Available Abstract This paper proposes intersymbol interference (ISI and interblock interference (IBI cancellation schemes at the transmitter and the receiver for the single-carrier block transmission with insufficient cyclic prefix (CP. The proposed scheme at the transmitter can exterminate the interferences by only setting some signals in the transmitted signal block to be the same as those of the previous transmitted signal block. On the other hand, the proposed schemes at the receiver can cancel the interferences without any change in the transmitted signals compared to the conventional method. The IBI components are reduced by using previously detected data signals, while for the ISI cancellation, we firstly change the defective channel matrix into a circulant matrix by using the tentative decisions, which are obtained by our newly derived frequency domain equalization (FDE, and then the conventional FDE is performed to compensate the ISI. Moreover, we propose a pilot signal configuration, which enables us to estimate a channel impulse response whose order is greater than the guard interval (GI. Computer simulations show that the proposed interference cancellation schemes can significantly improve bit error rate (BER performance, and the validity of the proposed channel estimation scheme is also demonstrated.

  6. Improved cache performance in Monte Carlo transport calculations using energy banding

    Science.gov (United States)

    Siegel, A.; Smith, K.; Felker, K.; Romano, P.; Forget, B.; Beckman, P.

    2014-04-01

    We present an energy banding algorithm for Monte Carlo (MC) neutral particle transport simulations which depend on large cross section lookup tables. In MC codes, read-only cross section data tables are accessed frequently, exhibit poor locality, and are typically too much large to fit in fast memory. Thus, performance is often limited by long latencies to RAM, or by off-node communication latencies when the data footprint is very large and must be decomposed on a distributed memory machine. The proposed energy banding algorithm allows maximal temporal reuse of data in band sizes that can flexibly accommodate different architectural features. The energy banding algorithm is general and has a number of benefits compared to the traditional approach. In the present analysis we explore its potential to achieve improvements in time-to-solution on modern cache-based architectures.

  7. Impulse: Memory System Support for Scientific Applications

    Directory of Open Access Journals (Sweden)

    John B. Carter

    1999-01-01

    Full Text Available Impulse is a new memory system architecture that adds two important features to a traditional memory controller. First, Impulse supports application‐specific optimizations through configurable physical address remapping. By remapping physical addresses, applications control how their data is accessed and cached, improving their cache and bus utilization. Second, Impulse supports prefetching at the memory controller, which can hide much of the latency of DRAM accesses. Because it requires no modification to processor, cache, or bus designs, Impulse can be adopted in conventional systems. In this paper we describe the design of the Impulse architecture, and show how an Impulse memory system can improve the performance of memory‐bound scientific applications. For instance, Impulse decreases the running time of the NAS conjugate gradient benchmark by 67%. We expect that Impulse will also benefit regularly strided, memory‐bound applications of commercial importance, such as database and multimedia programs.

  8. What happens during a Join? - Dissecting CPU and Memory Optimization Effects

    OpenAIRE

    Manegold, Stefan; Boncz, Peter; Kersten, Martin

    2000-01-01

    textabstractPerformance of modern hardware increasingly depends on proper utilization of both the memory cache hierarchy and parallel execution possibilities in todays super-scalar CPUs. Recent database research has demonstrated that database system performance severely suffers from poor utilization of these resources. In previous work, we presented join algorithms that strongly accelerate large equi-join by tuning the memory access pattern to match the characteristics of the memory cache sub...

  9. dCache on Steroids - Delegated Storage Solutions

    Science.gov (United States)

    Mkrtchyan, T.; Adeyemi, F.; Ashish, A.; Behrmann, G.; Fuhrmann, P.; Litvintsev, D.; Millar, P.; Rossi, A.; Sahakyan, M.; Starek, J.

    2017-10-01

    For over a decade, dCache.org has delivered a robust software used at more than 80 Universities and research institutes around the world, allowing these sites to provide reliable storage services for the WLCG experiments as well as many other scientific communities. The flexible architecture of dCache allows running it in a wide variety of configurations and platforms - from a SoC based all-in-one Raspberry-Pi up to hundreds of nodes in a multipetabyte installation. Due to lack of managed storage at the time, dCache implemented data placement, replication and data integrity directly. Today, many alternatives are available: S3, GlusterFS, CEPH and others. While such solutions position themselves as scalable storage systems, they cannot be used by many scientific communities out of the box. The absence of community-accepted authentication and authorization mechanisms, the use of product specific protocols and the lack of namespace are some of the reasons that prevent wide-scale adoption of these alternatives. Most of these limitations are already solved by dCache. By delegating low-level storage management functionality to the above-mentioned new systems and providing the missing layer through dCache, we provide a solution which combines the benefits of both worlds - industry standard storage building blocks with the access protocols and authentication required by scientific communities. In this paper, we focus on CEPH, a popular software for clustered storage that supports file, block and object interfaces. CEPH is often used in modern computing centers, for example as a backend to OpenStack services. We will show prototypes of dCache running with a CEPH backend and discuss the benefits and limitations of such an approach. We will also outline the roadmap for supporting ‘delegated storage’ within the dCache releases.

  10. Computing betweenness centrality in external memory

    DEFF Research Database (Denmark)

    Arge, Lars; Goodrich, Michael T.; Walderveen, Freek van

    2013-01-01

    Betweenness centrality is one of the most well-known measures of the importance of nodes in a social-network graph. In this paper we describe the first known external-memory and cache-oblivious algorithms for computing betweenness centrality. We present four different external-memory algorithms...

  11. Caching Efficiency Enhancement at Wireless Edges with Concerns on User’s Quality of Experience

    Directory of Open Access Journals (Sweden)

    Feng Li

    2018-01-01

    Full Text Available Content caching is a promising approach to enhancing bandwidth utilization and minimizing delivery delay for new-generation Internet applications. The design of content caching is based on the principles that popular contents are cached at appropriate network edges in order to reduce transmission delay and avoid backhaul bottleneck. In this paper, we propose a cooperative caching replacement and efficiency optimization scheme for IP-based wireless networks. Wireless edges are designed to establish a one-hop scope of caching information table for caching replacement in cases when there is not enough cache resource available within its own space. During the course, after receiving the caching request, every caching node should determine the weight of the required contents and provide a response according to the availability of its own caching space. Furthermore, to increase the caching efficiency from a practical perspective, we introduce the concept of quality of user experience (QoE and try to properly allocate the cache resource of the whole networks to better satisfy user demands. Different caching allocation strategies are devised to be adopted to enhance user QoE in various circumstances. Numerical results are further provided to justify the performance improvement of our proposal from various aspects.

  12. Horizontally scaling dCache SRM with the Terracotta platform

    International Nuclear Information System (INIS)

    Perelmutov, T; Crawford, M; Moibenko, A; Oleynik, G

    2011-01-01

    The dCache disk caching file system has been chosen by a majority of LHC experiments' Tier 1 centers for their data storage needs. It is also deployed at many Tier 2 centers. The Storage Resource Manager (SRM) is a standardized grid storage interface and a single point of remote entry into dCache, and hence is a critical component. SRM must scale to increasing transaction rates and remain resilient against changing usage patterns. The initial implementation of the SRM service in dCache suffered from an inability to support clustered deployment, and its performance was limited by the hardware of a single node. Using the Terracotta platform[l], we added the ability to horizontally scale the dCache SRM service to run on multiple nodes in a cluster configuration, coupled with network load balancing. This gives site administrators the ability to increase the performance and reliability of SRM service to face the ever-increasing requirements of LHC data handling. In this paper we will describe the previous limitations of the architecture SRM server and how the Terracotta platform allowed us to readily convert single node service into a highly scalable clustered application.

  13. A Scalable proxy cache for Grid Data Access

    International Nuclear Information System (INIS)

    Cristian Cirstea, Traian; Just Keijser, Jan; Arthur Koeroo, Oscar; Starink, Ronald; Alan Templon, Jeffrey

    2012-01-01

    We describe a prototype grid proxy cache system developed at Nikhef, motivated by a desire to construct the first building block of a future https-based Content Delivery Network for grid infrastructures. Two goals drove the project: firstly to provide a “native view” of the grid for desktop-type users, and secondly to improve performance for physics-analysis type use cases, where multiple passes are made over the same set of data (residing on the grid). We further constrained the design by requiring that the system should be made of standard components wherever possible. The prototype that emerged from this exercise is a horizontally-scalable, cooperating system of web server / cache nodes, fronted by a customized webDAV server. The webDAV server is custom only in the sense that it supports http redirects (providing horizontal scaling) and that the authentication module has, as back end, a proxy delegation chain that can be used by the cache nodes to retrieve files from the grid. The prototype was deployed at Nikhef and tested at a scale of several terabytes of data and approximately one hundred fast cores of computing. Both small and large files were tested, in a number of scenarios, and with various numbers of cache nodes, in order to understand the scaling properties of the system. For properly-dimensioned cache-node hardware, the system showed speedup of several integer factors for the analysis-type use cases. These results and others are presented and discussed.

  14. Transient Variable Caching in Java’s Stack-Based Intermediate Representation

    Directory of Open Access Journals (Sweden)

    Paul Týma

    1999-01-01

    Full Text Available Java’s stack‐based intermediate representation (IR is typically coerced to execute on register‐based architectures. Unoptimized compiled code dutifully replicates transient variable usage designated by the programmer and common optimization practices tend to introduce further usage (i.e., CSE, Loop‐invariant Code Motion, etc.. On register based machines, often transient variables are cached within registers (when available saving the expense of actually accessing memory. Unfortunately, in stack‐based environments because of the need to push and pop the transient values, further performance improvement is possible. This paper presents Transient Variable Caching (TVC, a technique for eliminating transient variable overhead whenever possible. This optimization would find a likely home in optimizers attached to the back of popular Java compilers. Side effects of the algorithm include significant instruction reordering and introduction of many stack‐manipulation operations. This combination has proven to greatly impede the ability to decompile stack‐based IR code sequences. The code that results from the transform is faster, smaller, and greatly impedes decompilation.

  15. Optimal Caching in Multicast 5G Networks with Opportunistic Spectrum Access

    KAUST Repository

    Emara, Mostafa; Elsawy, Hesham; Sorour, Sameh; Al-Ghadhban, Samir; Alouini, Mohamed-Slim; Al-Naffouri, Tareq Y.

    2018-01-01

    Cache-enabled small base station (SBS) densification is foreseen as a key component of 5G cellular networks. This architecture enables storing popular files at the network edge (i.e., SBS caches), which empowers local communication and alleviates

  16. Caching at the Mobile Edge: a Practical Implementation

    DEFF Research Database (Denmark)

    Poderys, Justas; Artuso, Matteo; Lensbøl, Claus Michael Oest

    2018-01-01

    Thanks to recent advances in mobile networks, it is becoming increasingly popular to access heterogeneous content from mobile terminals. There are, however, unique challenges in mobile networks that affect the perceived quality of experience (QoE) at the user end. One such challenge is the higher...... latency that users typically experience in mobile networks compared to wired ones. Cloud-based radio access networks with content caches at the base stations are seen as a key contributor in reducing the latency required to access content and thus improve the QoE at the mobile user terminal. In this paper...... for the mobile user obtained by caching content at the base stations. This is quantified with a comparison to non-cached content by means of ping tests (10–11% shorter times), a higher response rate for web traffic (1.73–3.6 times higher), and an improvement in the jitter (6% reduction)....

  17. CACHING DATA STORED IN SQL SERVER FOR OPTIMIZING THE PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Demian Horia

    2016-12-01

    Full Text Available This paper present the architecture of web site with different techniques used for optimize the performance of loading the web content. The architecture presented here is for e-commerce site developed on windows with MVC, IIS and Micosoft SQL Server. Caching the data is one technique used by the browsers, by the web servers itself or by proxy servers. Caching the data is made without the knowledge of users and need to provide to user the more recent information from the server. This means that caching mechanism has to be aware of any modification of data on the server. There are different information’s presented in e-commerce site related to products like images, code of product, description, properties or stock

  18. Analyzing data distribution on disk pools for dCache

    Energy Technology Data Exchange (ETDEWEB)

    Halstenberg, S; Jung, C; Ressmann, D [Forschungszentrum Karlsruhe, Steinbuch Centre for Computing, Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen (Germany)

    2010-04-01

    Most Tier-1 centers of LHC Computing Grid are using dCache as their storage system. dCache uses a cost model incorporating CPU and space costs for the distribution of data on its disk pools. Storage resources at Tier-1 centers are usually upgraded once or twice a year according to given milestones. One of the effects of this procedure is the accumulation of heterogeneous hardware resources. For a dCache system, a heterogeneous set of disk pools complicates the process of weighting CPU and space costs for an efficient distribution of data. In order to evaluate the data distribution on the disk pools, the distribution is simulated in Java. The results are discussed and suggestions for improving the weight scheme are given.

  19. Memory

    OpenAIRE

    Wager, Nadia

    2017-01-01

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

  20. Fast and Cache-Oblivious Dynamic Programming with Local Dependencies

    DEFF Research Database (Denmark)

    Bille, Philip; Stöckel, Morten

    2012-01-01

    are widely used in bioinformatics to compare DNA and protein sequences. These problems can all be solved using essentially the same dynamic programming scheme over a two-dimensional matrix, where each entry depends locally on at most 3 neighboring entries. We present a simple, fast, and cache......-oblivious algorithm for this type of local dynamic programming suitable for comparing large-scale strings. Our algorithm outperforms the previous state-of-the-art solutions. Surprisingly, our new simple algorithm is competitive with a complicated, optimized, and tuned implementation of the best cache-aware algorithm...

  1. Web proxy cache replacement strategies simulation, implementation, and performance evaluation

    CERN Document Server

    ElAarag, Hala; Cobb, Jake

    2013-01-01

    This work presents a study of cache replacement strategies designed for static web content. Proxy servers can improve performance by caching static web content such as cascading style sheets, java script source files, and large files such as images. This topic is particularly important in wireless ad hoc networks, in which mobile devices act as proxy servers for a group of other mobile devices. Opening chapters present an introduction to web requests and the characteristics of web objects, web proxy servers and Squid, and artificial neural networks. This is followed by a comprehensive review o

  2. Memory hierarchy using row-based compression

    Science.gov (United States)

    Loh, Gabriel H.; O'Connor, James M.

    2016-10-25

    A system includes a first memory and a device coupleable to the first memory. The device includes a second memory to cache data from the first memory. The second memory includes a plurality of rows, each row including a corresponding set of compressed data blocks of non-uniform sizes and a corresponding set of tag blocks. Each tag block represents a corresponding compressed data block of the row. The device further includes decompression logic to decompress data blocks accessed from the second memory. The device further includes compression logic to compress data blocks to be stored in the second memory.

  3. Parallel External Memory Graph Algorithms

    DEFF Research Database (Denmark)

    Arge, Lars Allan; Goodrich, Michael T.; Sitchinava, Nodari

    2010-01-01

    In this paper, we study parallel I/O efficient graph algorithms in the Parallel External Memory (PEM) model, one o f the private-cache chip multiprocessor (CMP) models. We study the fundamental problem of list ranking which leads to efficient solutions to problems on trees, such as computing lowest...... an optimal speedup of ¿(P) in parallel I/O complexity and parallel computation time, compared to the single-processor external memory counterparts....

  4. Dynamic web cache publishing for IaaS clouds using Shoal

    International Nuclear Information System (INIS)

    Gable, Ian; Chester, Michael; Berghaus, Frank; Leavett-Brown, Colin; Paterson, Michael; Prior, Robert; Sobie, Randall; Taylor, Ryan; Armstrong, Patrick; Charbonneau, Andre

    2014-01-01

    We have developed a highly scalable application, called Shoal, for tracking and utilizing a distributed set of HTTP web caches. Our application uses the Squid HTTP cache. Squid servers advertise their existence to the Shoal server via AMQP messaging by running Shoal Agent. The Shoal server provides a simple REST interface that allows clients to determine their closest Squid cache. Our goal is to dynamically instantiate Squid caches on IaaS clouds in response to client demand. Shoal provides the VMs on IaaS clouds with the location of the nearest dynamically instantiated Squid Cache

  5. Cache Timing Analysis of LFSR-based Stream Ciphers

    DEFF Research Database (Denmark)

    Zenner, Erik; Leander, Gregor; Hawkes, Philip

    2009-01-01

    Cache timing attacks are a class of side-channel attacks that is applicable against certain software implementations. They have generated significant interest when demonstrated against the Advanced Encryption Standard (AES), but have more recently also been applied against other cryptographic...

  6. ARC Cache: A solution for lightweight Grid sites in ATLAS

    CERN Document Server

    Garonne, Vincent; The ATLAS collaboration

    2016-01-01

    Many Grid sites have the need to reduce operational manpower, and running a storage element consumes a large amount of effort. In addition, setting up a new Grid site including a storage element involves a steep learning curve and large investment of time. For these reasons so-called storage-less sites are becoming more popular as a way to provide Grid computing resources with less operational overhead. ARC CE is a widely-used and mature Grid middleware which was designed from the start to be used on sites with no persistent storage element. Instead, it maintains a local self-managing cache of data which retains popular data for future jobs. As the cache is simply an area on a local posix shared filesystem with no external-facing service, it requires no extra maintenance. The cache can be scaled up as required by increasing the size of the filesystem or adding new filesystems. This paper describes how ARC CE and its cache are an ideal solution for lightweight Grid sites in the ATLAS experiment, and the integr...

  7. Caching Over-The-Top Services, the Netflix Case

    DEFF Research Database (Denmark)

    Jensen, Stefan; Jensen, Michael; Gutierrez Lopez, Jose Manuel

    2015-01-01

    Problem (LLB-CFL). The solution search processes are implemented based on Genetic Algorithms (GA), designing genetic operators highly targeted towards this specific problem. The proposed methods are applied to a case study focusing on the demand and cache specifications of Netflix, and framed into a real...

  8. A distributed storage system with dCache

    Science.gov (United States)

    Behrmann, G.; Fuhrmann, P.; Grønager, M.; Kleist, J.

    2008-07-01

    The LCG collaboration is encompassed by a number of Tier 1 centers. The Nordic LCG Tier 1, operated by NDGF, is in contrast to many other Tier 1 centers distributed over the Nordic countries. A distributed setup was chosen for both political and technical reasons, but also provides a number of unique challenges. dCache is well known and respected as a powerful distributed storage resource manager, and was chosen for implementing the storage aspects of the Nordic Tier 1. In contrast to classic dCache deployments, we deploy dCache over a WAN with limited bandwidth, high latency, frequent network failures, and spanning many administrative domains. These properties provide unique challenges, covering topics such as security, administration, maintenance, upgradability, reliability, and performance. Our initial focus has been on implementing the GFD.47 OGF recommendation (which introduced the GridFTP 2 protocol) in dCache and the Globus Toolkit. Compared to GridFTP 1, GridFTP 2 allows for more intelligent data flow between clients and storage pools, thus enabling more efficient use of our limited bandwidth.

  9. Effective caching of shortest paths for location-based services

    DEFF Research Database (Denmark)

    Jensen, Christian S.; Thomsen, Jeppe Rishede; Yiu, Man Lung

    2012-01-01

    Web search is ubiquitous in our daily lives. Caching has been extensively used to reduce the computation time of the search engine and reduce the network traffic beyond a proxy server. Another form of web search, known as online shortest path search, is popular due to advances in geo...

  10. Language-Based Caching of Dynamically Generated HTML

    DEFF Research Database (Denmark)

    Brabrand, Claus; Møller, Anders; Olesen, Steffan

    2002-01-01

    Increasingly, HTML documents are dynamically generated by interactive Web services. To ensure that the client is presented with the newest versions of such documents it is customary to disable client caching causing a seemingly inevitable performance penalty. In the system, dynamic HTML documents...

  11. Cache Timing Analysis of eStream Finalists

    DEFF Research Database (Denmark)

    Zenner, Erik

    2009-01-01

    Cache Timing Attacks have attracted a lot of cryptographic attention due to their relevance for the AES. However, their applicability to other cryptographic primitives is less well researched. In this talk, we give an overview over our analysis of the stream ciphers that were selected for phase 3...

  12. dCache, agile adoption of storage technology

    CERN Multimedia

    CERN. Geneva

    2012-01-01

    For over a decade, dCache has been synonymous with large-capacity, fault-tolerant storage using commodity hardware that supports seamless data migration to and from tape. Over that time, it has satisfied the requirements of various demanding scientific user communities to store their data, transfer it between sites and fast, site-local access. When the dCache project started, the focus was on managing a relatively small disk cache in front of large tape archives. Over the project's lifetime storage technology has changed. During this period, technology changes have driven down the cost-per-GiB of harddisks. This resulted in a shift towards systems where the majority of data is stored on disk. More recently, the availability of Solid State Disks, while not yet a replacement for magnetic disks, offers an intriguing opportunity for significant performance improvement if they can be used intelligently within an existing system. New technologies provide new opportunities and dCache user communities' computi...

  13. A distributed storage system with dCache

    International Nuclear Information System (INIS)

    Behrmann, G; Groenager, M; Fuhrmann, P; Kleist, J

    2008-01-01

    The LCG collaboration is encompassed by a number of Tier 1 centers. The Nordic LCG Tier 1, operated by NDGF, is in contrast to many other Tier 1 centers distributed over the Nordic countries. A distributed setup was chosen for both political and technical reasons, but also provides a number of unique challenges. dCache is well known and respected as a powerful distributed storage resource manager, and was chosen for implementing the storage aspects of the Nordic Tier 1. In contrast to classic dCache deployments, we deploy dCache over a WAN with limited bandwidth, high latency, frequent network failures, and spanning many administrative domains. These properties provide unique challenges, covering topics such as security, administration, maintenance, upgradability, reliability, and performance. Our initial focus has been on implementing the GFD.47 OGF recommendation (which introduced the GridFTP 2 protocol) in dCache and the Globus Toolkit. Compared to GridFTP 1, GridFTP 2 allows for more intelligent data flow between clients and storage pools, thus enabling more efficient use of our limited bandwidth

  14. Tier 3 batch system data locality via managed caches

    Science.gov (United States)

    Fischer, Max; Giffels, Manuel; Jung, Christopher; Kühn, Eileen; Quast, Günter

    2015-05-01

    Modern data processing increasingly relies on data locality for performance and scalability, whereas the common HEP approaches aim for uniform resource pools with minimal locality, recently even across site boundaries. To combine advantages of both, the High- Performance Data Analysis (HPDA) Tier 3 concept opportunistically establishes data locality via coordinated caches. In accordance with HEP Tier 3 activities, the design incorporates two major assumptions: First, only a fraction of data is accessed regularly and thus the deciding factor for overall throughput. Second, data access may fallback to non-local, making permanent local data availability an inefficient resource usage strategy. Based on this, the HPDA design generically extends available storage hierarchies into the batch system. Using the batch system itself for scheduling file locality, an array of independent caches on the worker nodes is dynamically populated with high-profile data. Cache state information is exposed to the batch system both for managing caches and scheduling jobs. As a result, users directly work with a regular, adequately sized storage system. However, their automated batch processes are presented with local replications of data whenever possible.

  15. Memories.

    Science.gov (United States)

    Brand, Judith, Ed.

    1998-01-01

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

  16. Iterative Frequency-Domain Channel Estimation and Equalization for Ultra-Wideband Systems with Short Cyclic Prefix

    Directory of Open Access Journals (Sweden)

    Salim Bahçeci

    2010-01-01

    Full Text Available In impulse radio ultra-wideband (IR-UWB systems where the channel lengths are on the order of a few hundred taps, conventional use of frequency-domain (FD processing for channel estimation and equalization may not be feasible because the need to add a cyclic prefix (CP to each block causes a significant reduction in the spectral efficiency. On the other hand, using no or short CP causes the interblock interference (IBI and thus degradation in the receiver performance. Therefore, in order to utilize FD receiver processing UWB systems without a significant loss in the spectral efficiency and the performance, IBI cancellation mechanisms are needed in both the channel estimation and equalization operations. For this reason, in this paper, we consider the joint FD channel estimation and equalization for IR-UWB systems with short cyclic prefix (CP and propose a novel iterative receiver employing soft IBI estimation and cancellation within both its FD channel estimator and FD equalizer components. We show by simulation results that the proposed FD receiver attains performances close to that of the full CP case in both line-of-sight (LOS and non-line-of-sight (NLOS UWB channels after only a few iterations.

  17. A trace-driven analysis of name and attribute caching in a distributed system

    Science.gov (United States)

    Shirriff, Ken W.; Ousterhout, John K.

    1992-01-01

    This paper presents the results of simulating file name and attribute caching on client machines in a distributed file system. The simulation used trace data gathered on a network of about 40 workstations. Caching was found to be advantageous: a cache on each client containing just 10 directories had a 91 percent hit rate on name look ups. Entry-based name caches (holding individual directory entries) had poorer performance for several reasons, resulting in a maximum hit rate of about 83 percent. File attribute caching obtained a 90 percent hit rate with a cache on each machine of the attributes for 30 files. The simulations show that maintaining cache consistency between machines is not a significant problem; only 1 in 400 name component look ups required invalidation of a remotely cached entry. Process migration to remote machines had little effect on caching. Caching was less successful in heavily shared and modified directories such as /tmp, but there weren't enough references to /tmp overall to affect the results significantly. We estimate that adding name and attribute caching to the Sprite operating system could reduce server load by 36 percent and the number of network packets by 30 percent.

  18. Smart caching based on mobile agent of power WebGIS platform.

    Science.gov (United States)

    Wang, Xiaohui; Wu, Kehe; Chen, Fei

    2013-01-01

    Power information construction is developing towards intensive, platform, distributed direction with the expansion of power grid and improvement of information technology. In order to meet the trend, power WebGIS was designed and developed. In this paper, we first discuss the architecture and functionality of power WebGIS, and then we study caching technology in detail, which contains dynamic display cache model, caching structure based on mobile agent, and cache data model. We have designed experiments of different data capacity to contrast performance between WebGIS with the proposed caching model and traditional WebGIS. The experimental results showed that, with the same hardware environment, the response time of WebGIS with and without caching model increased as data capacity growing, while the larger the data was, the higher the performance of WebGIS with proposed caching model improved.

  19. Energy Efficient Caching in Backhaul-Aware Cellular Networks with Dynamic Content Popularity

    Directory of Open Access Journals (Sweden)

    Jiequ Ji

    2018-01-01

    Full Text Available Caching popular contents at base stations (BSs has been regarded as an effective approach to alleviate the backhaul load and to improve the quality of service. To meet the explosive data traffic demand and to save energy consumption, energy efficiency (EE has become an extremely important performance index for the 5th generation (5G cellular networks. In general, there are two ways for improving the EE for caching, that is, improving the cache-hit rate and optimizing the cache size. In this work, we investigate the energy efficient caching problem in backhaul-aware cellular networks jointly considering these two approaches. Note that most existing works are based on the assumption that the content catalog and popularity are static. However, in practice, content popularity is dynamic. To timely estimate the dynamic content popularity, we propose a method based on shot noise model (SNM. Then we propose a distributed caching policy to improve the cache-hit rate in such a dynamic environment. Furthermore, we analyze the tradeoff between energy efficiency and cache capacity for which an optimization is formulated. We prove its convexity and derive a closed-form optimal cache capacity for maximizing the EE. Simulation results validate the proposed scheme and show that EE can be improved with appropriate choice of cache capacity.

  20. Time-Predictable Virtual Memory

    DEFF Research Database (Denmark)

    Puffitsch, Wolfgang; Schoeberl, Martin

    2016-01-01

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

  1. A selective logging mechanism for hardware transactional memory systems

    OpenAIRE

    Lupon Navazo, Marc; Magklis, Grigorios; González Colás, Antonio María

    2011-01-01

    Log-based Hardware Transactional Memory (HTM) systems offer an elegant solution to handle speculative data that overflow transactional L1 caches. By keeping the pre-transactional values on a software-resident log, speculative values can be safely moved across the memory hierarchy, without requiring expensive searches on L1 misses or commits.

  2. Study on data acquisition system based on reconfigurable cache technology

    Science.gov (United States)

    Zhang, Qinchuan; Li, Min; Jiang, Jun

    2018-03-01

    Waveform capture rate is one of the key features of digital acquisition systems, which represents the waveform processing capability of the system in a unit time. The higher the waveform capture rate is, the larger the chance to capture elusive events is and the more reliable the test result is. First, this paper analyzes the impact of several factors on the waveform capture rate of the system, then the novel technology based on reconfigurable cache is further proposed to optimize system architecture, and the simulation results show that the signal-to-noise ratio of signal, capacity, and structure of cache have significant effects on the waveform capture rate. Finally, the technology is demonstrated by the engineering practice, and the results show that the waveform capture rate of the system is improved substantially without significant increase of system's cost, and the technology proposed has a broad application prospect.

  3. I-Structure software cache for distributed applications

    Directory of Open Access Journals (Sweden)

    Alfredo Cristóbal Salas

    2004-01-01

    Full Text Available En este artículo, describimos el caché de software I-Structure para entornos de memoria distribuida (D-ISSC, lo cual toma ventaja de la localidad de los datos mientras mantiene la capacidad de tolerancia a la latencia de sistemas de memoria I-Structure. Las facilidades de programación de los programas MPI, le ocultan los problemas de sincronización al programador. Nuestra evaluación experimental usando un conjunto de pruebas de rendimiento indica que clusters de PC con I-Structure y su mecanismo de cache D-ISSC son más robustos. El sistema puede acelerar aplicaciones de comunicación intensiva regulares e irregulares.

  4. The Potential Role of Cache Mechanism for Complicated Design Optimization

    International Nuclear Information System (INIS)

    Noriyasu, Hirokawa; Fujita, Kikuo

    2002-01-01

    This paper discusses the potential role of cache mechanism for complicated design optimization While design optimization is an application of mathematical programming techniques to engineering design problems over numerical computation, its progress has been coevolutionary. The trend in such progress indicates that more complicated applications become the next target of design optimization beyond growth of computational resources. As the progress in the past two decades had required response surface techniques, decomposition techniques, etc., any new framework must be introduced for the future of design optimization methods. This paper proposes a possibility of what we call cache mechanism for mediating the coming challenge and briefly demonstrates some promises in the idea of Voronoi diagram based cumulative approximation as an example of its implementation, development of strict robust design, extension of design optimization for product variety

  5. Prefixálně-sufixální adjektiva v pomístních jménech v Čechách

    Czech Academy of Sciences Publication Activity Database

    Štěpán, Pavel

    2011-01-01

    Roč. 94, č. 4 (2011), s. 194-203 ISSN 0027-8203 Institutional research plan: CEZ:AV0Z90610518 Keywords : minor place-names * adjectives * prefixal-suffixal formation * word-formation Subject RIV: AI - Linguistics

  6. An Economic Model for Self-tuned Cloud Caching

    OpenAIRE

    Dash, Debabrata; Kantere, Verena; Ailamaki, Anastasia

    2009-01-01

    Cloud computing, the new trend for service infrastructures requires user multi-tenancy as well as minimal capital expenditure. In a cloud that services large amounts of data that are massively collected and queried, such as scientific data, users typically pay for query services. The cloud supports caching of data in order to provide quality query services. User payments cover query execution costs and maintenance of cloud infrastructure, and incur cloud profit. The challenge resides in provi...

  7. Big Data Caching for Networking: Moving from Cloud to Edge

    OpenAIRE

    Zeydan, Engin; Baştuğ, Ejder; Bennis, Mehdi; Kader, Manhal Abdel; Karatepe, Alper; Er, Ahmet Salih; Debbah, Mérouane

    2016-01-01

    In order to cope with the relentless data tsunami in $5G$ wireless networks, current approaches such as acquiring new spectrum, deploying more base stations (BSs) and increasing nodes in mobile packet core networks are becoming ineffective in terms of scalability, cost and flexibility. In this regard, context-aware $5$G networks with edge/cloud computing and exploitation of \\emph{big data} analytics can yield significant gains to mobile operators. In this article, proactive content caching in...

  8. Design issues and caching strategies for CD-ROM-based multimedia storage

    Science.gov (United States)

    Shastri, Vijnan; Rajaraman, V.; Jamadagni, H. S.; Venkat-Rangan, P.; Sampath-Kumar, Srihari

    1996-03-01

    CD-ROMs have proliferated as a distribution media for desktop machines for a large variety of multimedia applications (targeted for a single-user environment) like encyclopedias, magazines and games. With CD-ROM capacities up to 3 GB being available in the near future, they will form an integral part of Video on Demand (VoD) servers to store full-length movies and multimedia. In the first section of this paper we look at issues related to the single- user desktop environment. Since these multimedia applications are highly interactive in nature, we take a pragmatic approach, and have made a detailed study of the multimedia application behavior in terms of the I/O request patterns generated to the CD-ROM subsystem by tracing these patterns. We discuss prefetch buffer design and seek time characteristics in the context of the analysis of these traces. We also propose an adaptive main-memory hosted cache that receives caching hints from the application to reduce the latency when the user moves from one node of the hyper graph to another. In the second section we look at the use of CD-ROM in a VoD server and discuss the problem of scheduling multiple request streams and buffer management in this scenario. We adapt the C-SCAN (Circular SCAN) algorithm to suit the CD-ROM drive characteristics and prove that it is optimal in terms of buffer size management. We provide computationally inexpensive relations by which this algorithm can be implemented. We then propose an admission control algorithm which admits new request streams without disrupting the continuity of playback of the previous request streams. The algorithm also supports operations such as fast forward and replay. Finally, we discuss the problem of optimal placement of MPEG streams on CD-ROMs in the third section.

  9. On the Performance of the Cache Coding Protocol

    Directory of Open Access Journals (Sweden)

    Behnaz Maboudi

    2018-03-01

    Full Text Available Network coding approaches typically consider an unrestricted recoding of coded packets in the relay nodes to increase performance. However, this can expose the system to pollution attacks that cannot be detected during transmission, until the receivers attempt to recover the data. To prevent these attacks while allowing for the benefits of coding in mesh networks, the cache coding protocol was proposed. This protocol only allows recoding at the relays when the relay has received enough coded packets to decode an entire generation of packets. At that point, the relay node recodes and signs the recoded packets with its own private key, allowing the system to detect and minimize the effect of pollution attacks and making the relays accountable for changes on the data. This paper analyzes the delay performance of cache coding to understand the security-performance trade-off of this scheme. We introduce an analytical model for the case of two relays in an erasure channel relying on an absorbing Markov chain and an approximate model to estimate the performance in terms of the number of transmissions before successfully decoding at the receiver. We confirm our analysis using simulation results. We show that cache coding can overcome the security issues of unrestricted recoding with only a moderate decrease in system performance.

  10. Using Shadow Page Cache to Improve Isolated Drivers Performance

    Directory of Open Access Journals (Sweden)

    Hao Zheng

    2015-01-01

    Full Text Available With the advantage of the reusability property of the virtualization technology, users can reuse various types and versions of existing operating systems and drivers in a virtual machine, so as to customize their application environment. In order to prevent users’ virtualization environments being impacted by driver faults in virtual machine, Chariot examines the correctness of driver’s write operations by the method of combining a driver’s write operation capture and a driver’s private access control table. However, this method needs to keep the write permission of shadow page table as read-only, so as to capture isolated driver’s write operations through page faults, which adversely affect the performance of the driver. Based on delaying setting frequently used shadow pages’ write permissions to read-only, this paper proposes an algorithm using shadow page cache to improve the performance of isolated drivers and carefully study the relationship between the performance of drivers and the size of shadow page cache. Experimental results show that, through the shadow page cache, the performance of isolated drivers can be greatly improved without impacting Chariot’s reliability too much.

  11. Efficient Resource Scheduling by Exploiting Relay Cache for Cellular Networks

    Directory of Open Access Journals (Sweden)

    Chun He

    2015-01-01

    Full Text Available In relay-enhanced cellular systems, throughput of User Equipment (UE is constrained by the bottleneck of the two-hop link, backhaul link (or the first hop link, and access link (the second hop link. To maximize the throughput, resource allocation should be coordinated between these two hops. A common resource scheduling algorithm, Adaptive Distributed Proportional Fair, only ensures that the throughput of the first hop is greater than or equal to that of the second hop. But it cannot guarantee a good balance of the throughput and fairness between the two hops. In this paper, we propose a Two-Hop Balanced Distributed Scheduling (TBS algorithm by exploiting relay cache for non-real-time data traffic. The evolved Node Basestation (eNB adaptively adjusts the number of Resource Blocks (RBs allocated to the backhaul link and direct links based on the cache information of relays. Each relay allocates RBs for relay UEs based on the size of the relay UE’s Transport Block. We also design a relay UE’s ACK feedback mechanism to update the data at relay cache. Simulation results show that the proposed TBS can effectively improve resource utilization and achieve a good trade-off between system throughput and fairness by balancing the throughput of backhaul and access link.

  12. New distributive web-caching technique for VOD services

    Science.gov (United States)

    Kim, Iksoo; Woo, Yoseop; Hwang, Taejune; Choi, Jintak; Kim, Youngjune

    2002-12-01

    At present, one of the most popular services through internet is on-demand services including VOD, EOD and NOD. But the main problems for on-demand service are excessive load of server and insufficiency of network resources. Therefore the service providers require a powerful expensive server and clients are faced with long end-to-end delay and network congestion problem. This paper presents a new distributive web-caching technique for fluent VOD services using distributed proxies in Head-end-Network (HNET). The HNET consists of a Switching-Agent (SA) as a control node, some Head-end Nodes (HEN) as proxies and clients connected to HEN. And each HEN is composing a LAN. Clients request VOD services to server through a HEN and SA. The SA operates the heart of HNET, all the operations using proposed distributive caching technique perform under the control of SA. This technique stores some parts of a requested video on the corresponding HENs when clients connected to each HEN request an identical video. Thus, clients access those HENs (proxies) alternatively for acquiring video streams. Eventually, this fact leads to equi-loaded proxy (HEN). We adopt the cache replacement strategy using the combination of LRU, LFU, remove streams from other HEN prior to server streams and the method of replacing the first block of video last to reduce end-to end delay.

  13. Using shadow page cache to improve isolated drivers performance.

    Science.gov (United States)

    Zheng, Hao; Dong, Xiaoshe; Wang, Endong; Chen, Baoke; Zhu, Zhengdong; Liu, Chengzhe

    2015-01-01

    With the advantage of the reusability property of the virtualization technology, users can reuse various types and versions of existing operating systems and drivers in a virtual machine, so as to customize their application environment. In order to prevent users' virtualization environments being impacted by driver faults in virtual machine, Chariot examines the correctness of driver's write operations by the method of combining a driver's write operation capture and a driver's private access control table. However, this method needs to keep the write permission of shadow page table as read-only, so as to capture isolated driver's write operations through page faults, which adversely affect the performance of the driver. Based on delaying setting frequently used shadow pages' write permissions to read-only, this paper proposes an algorithm using shadow page cache to improve the performance of isolated drivers and carefully study the relationship between the performance of drivers and the size of shadow page cache. Experimental results show that, through the shadow page cache, the performance of isolated drivers can be greatly improved without impacting Chariot's reliability too much.

  14. Storageless and caching Tier-2 models in the UK context

    Science.gov (United States)

    Cadellin Skipsey, Samuel; Dewhurst, Alastair; Crooks, David; MacMahon, Ewan; Roy, Gareth; Smith, Oliver; Mohammed, Kashif; Brew, Chris; Britton, David

    2017-10-01

    Operational and other pressures have lead to WLCG experiments moving increasingly to a stratified model for Tier-2 resources, where “fat” Tier-2s (“T2Ds”) and “thin” Tier-2s (“T2Cs”) provide different levels of service. In the UK, this distinction is also encouraged by the terms of the current GridPP5 funding model. In anticipation of this, testing has been performed on the implications, and potential implementation, of such a distinction in our resources. In particular, this presentation presents the results of testing of storage T2Cs, where the “thin” nature is expressed by the site having either no local data storage, or only a thin caching layer; data is streamed or copied from a “nearby” T2D when needed by jobs. In OSG, this model has been adopted successfully for CMS AAA sites; but the network topology and capacity in the USA is significantly different to that in the UK (and much of Europe). We present the result of several operational tests: the in-production University College London (UCL) site, which runs ATLAS workloads using storage at the Queen Mary University of London (QMUL) site; the Oxford site, which has had scaling tests performed against T2Ds in various locations in the UK (to test network effects); and the Durham site, which has been testing the specific ATLAS caching solution of “Rucio Cache” integration with ARC’s caching layer.

  15. Effects of simulated mountain lion caching on decomposition of ungulate carcasses

    Science.gov (United States)

    Bischoff-Mattson, Z.; Mattson, D.

    2009-01-01

    Caching of animal remains is common among carnivorous species of all sizes, yet the effects of caching on larger prey are unstudied. We conducted a summer field experiment designed to test the effects of simulated mountain lion (Puma concolor) caching on mass loss, relative temperature, and odor dissemination of 9 prey-like carcasses. We deployed all but one of the carcasses in pairs, with one of each pair exposed and the other shaded and shallowly buried (cached). Caching substantially reduced wastage during dry and hot (drought) but not wet and cool (monsoon) periods, and it also reduced temperature and discernable odor to some degree during both seasons. These results are consistent with the hypotheses that caching serves to both reduce competition from arthropods and microbes and reduce odds of detection by larger vertebrates such as bears (Ursus spp.), wolves (Canis lupus), or other lions.

  16. Analisis Algoritma Pergantian Cache Pada Proxy Web Server Internet Dengan Simulasi

    OpenAIRE

    Nurwarsito, Heru

    2007-01-01

    Pertumbuhan jumlah client internet dari waktu ke waktu terus bertambah, maka respon akses internet menjadi semakin lambat. Untuk membantu kecepatan akses tersebut maka diperlukan cache pada Proxy Server. Penelitian ini bertujuan untuk menganalisis performansi Proxy Server pada Jaringan Internet terhadap penggunaan algoritma pergantian cache-nya.Analisis Algoritma Pergantian Cache Pada Proxy Server didesain dengan metoda pemodelan simulasi jaringan internet yang terdiri dari Web server, Proxy ...

  17. Traversal Caches: A Framework for FPGA Acceleration of Pointer Data Structures

    Directory of Open Access Journals (Sweden)

    James Coole

    2010-01-01

    Full Text Available Field-programmable gate arrays (FPGAs and other reconfigurable computing (RC devices have been widely shown to have numerous advantages including order of magnitude performance and power improvements compared to microprocessors for some applications. Unfortunately, FPGA usage has largely been limited to applications exhibiting sequential memory access patterns, thereby prohibiting acceleration of important applications with irregular patterns (e.g., pointer-based data structures. In this paper, we present a design pattern for RC application development that serializes irregular data structure traversals online into a traversal cache, which allows the corresponding data to be efficiently streamed to the FPGA. The paper presents a generalized framework that benefits applications with repeated traversals, which we show can achieve between 7x and 29x speedup over pointer-based software. For applications without strictly repeated traversals, we present application-specialized extensions that benefit applications with highly similar traversals by exploiting similarity to improve memory bandwidth and execute multiple traversals in parallel. We show that these extensions can achieve a speedup between 11x and 70x on a Virtex4 LX100 for Barnes-Hut n-body simulation.

  18. Organizing the pantry: cache management improves quality of overwinter food stores in a montane mammal

    Science.gov (United States)

    Jakopak, Rhiannon P.; Hall, L. Embere; Chalfoun, Anna D.

    2017-01-01

    Many mammals create food stores to enhance overwinter survival in seasonal environments. Strategic arrangement of food within caches may facilitate the physical integrity of the cache or improve access to high-quality food to ensure that cached resources meet future nutritional demands. We used the American pika (Ochotona princeps), a food-caching lagomorph, to evaluate variation in haypile (cache) structure (i.e., horizontal layering by plant functional group) in Wyoming, United States. Fifty-five percent of 62 haypiles contained at least 2 discrete layers of vegetation. Adults and juveniles layered haypiles in similar proportions. The probability of layering increased with haypile volume, but not haypile number per individual or nearby forage diversity. Vegetation cached in layered haypiles was also higher in nitrogen compared to vegetation in unlayered piles. We found that American pikas frequently structured their food caches, structured caches were larger, and the cached vegetation in structured piles was of higher nutritional quality. Improving access to stable, high-quality vegetation in haypiles, a critical overwinter food resource, may allow individuals to better persist amidst harsh conditions.

  19. Behavior-aware cache hierarchy optimization for low-power multi-core embedded systems

    Science.gov (United States)

    Zhao, Huatao; Luo, Xiao; Zhu, Chen; Watanabe, Takahiro; Zhu, Tianbo

    2017-07-01

    In modern embedded systems, the increasing number of cores requires efficient cache hierarchies to ensure data throughput, but such cache hierarchies are restricted by their tumid size and interference accesses which leads to both performance degradation and wasted energy. In this paper, we firstly propose a behavior-aware cache hierarchy (BACH) which can optimally allocate the multi-level cache resources to many cores and highly improved the efficiency of cache hierarchy, resulting in low energy consumption. The BACH takes full advantage of the explored application behaviors and runtime cache resource demands as the cache allocation bases, so that we can optimally configure the cache hierarchy to meet the runtime demand. The BACH was implemented on the GEM5 simulator. The experimental results show that energy consumption of a three-level cache hierarchy can be saved from 5.29% up to 27.94% compared with other key approaches while the performance of the multi-core system even has a slight improvement counting in hardware overhead.

  20. Cooperative Caching in Mobile Ad Hoc Networks Based on Data Utility

    Directory of Open Access Journals (Sweden)

    Narottam Chand

    2007-01-01

    Full Text Available Cooperative caching, which allows sharing and coordination of cached data among clients, is a potential technique to improve the data access performance and availability in mobile ad hoc networks. However, variable data sizes, frequent data updates, limited client resources, insufficient wireless bandwidth and client's mobility make cache management a challenge. In this paper, we propose a utility based cache replacement policy, least utility value (LUV, to improve the data availability and reduce the local cache miss ratio. LUV considers several factors that affect cache performance, namely access probability, distance between the requester and data source/cache, coherency and data size. A cooperative cache management strategy, Zone Cooperative (ZC, is developed that employs LUV as replacement policy. In ZC one-hop neighbors of a client form a cooperation zone since the cost for communication with them is low both in terms of energy consumption and message exchange. Simulation experiments have been conducted to evaluate the performance of LUV based ZC caching strategy. The simulation results show that, LUV replacement policy substantially outperforms the LRU policy.

  1. Optimal Caching in Multicast 5G Networks with Opportunistic Spectrum Access

    KAUST Repository

    Emara, Mostafa

    2018-01-15

    Cache-enabled small base station (SBS) densification is foreseen as a key component of 5G cellular networks. This architecture enables storing popular files at the network edge (i.e., SBS caches), which empowers local communication and alleviates traffic congestions at the core/backhaul network. This paper develops a mathematical framework, based on stochastic geometry, to characterize the hit probability of a cache-enabled multicast 5G network with SBS multi-channel capabilities and opportunistic spectrum access. To this end, we first derive the hit probability by characterizing opportunistic spectrum access success probabilities, service distance distributions, and coverage probabilities. The optimal caching distribution to maximize the hit probability is then computed. The performance and trade-offs of the derived optimal caching distributions are then assessed and compared with two widely employed caching distribution schemes, namely uniform and Zipf caching, through numerical results and extensive simulations. It is shown that the Zipf caching almost optimal only in scenarios with large number of available channels and large cache sizes.

  2. One-way shared memory

    DEFF Research Database (Denmark)

    Schoeberl, Martin

    2018-01-01

    Standard multicore processors use the shared main memory via the on-chip caches for communication between cores. However, this form of communication has two limitations: (1) it is hardly time-predictable and therefore not a good solution for real-time systems and (2) this single shared memory...... is a bottleneck in the system. This paper presents a communication architecture for time-predictable multicore systems where core-local memories are distributed on the chip. A network-on-chip constantly copies data from a sender core-local memory to a receiver core-local memory. As this copying is performed...... in one direction we call this architecture a one-way shared memory. With the use of time-division multiplexing for the memory accesses and the network-on-chip routers we achieve a time-predictable solution where the communication latency and bandwidth can be bounded. An example architecture for a 3...

  3. California scrub-jays reduce visual cues available to potential pilferers by matching food colour to caching substrate.

    Science.gov (United States)

    Kelley, Laura A; Clayton, Nicola S

    2017-07-01

    Some animals hide food to consume later; however, these caches are susceptible to theft by conspecifics and heterospecifics. Caching animals can use protective strategies to minimize sensory cues available to potential pilferers, such as caching in shaded areas and in quiet substrate. Background matching (where object patterning matches the visual background) is commonly seen in prey animals to reduce conspicuousness, and caching animals may also use this tactic to hide caches, for example, by hiding coloured food in a similar coloured substrate. We tested whether California scrub-jays ( Aphelocoma californica ) camouflage their food in this way by offering them caching substrates that either matched or did not match the colour of food available for caching. We also determined whether this caching behaviour was sensitive to social context by allowing the birds to cache when a conspecific potential pilferer could be both heard and seen (acoustic and visual cues present), or unseen (acoustic cues only). When caching events could be both heard and seen by a potential pilferer, birds cached randomly in matching and non-matching substrates. However, they preferentially hid food in the substrate that matched the food colour when only acoustic cues were present. This is a novel cache protection strategy that also appears to be sensitive to social context. We conclude that studies of cache protection strategies should consider the perceptual capabilities of the cacher and potential pilferers. © 2017 The Author(s).

  4. On the Feasibility of Prefetching and Caching for Online TV Services: A Measurement Study on Hulu

    Science.gov (United States)

    Krishnappa, Dilip Kumar; Khemmarat, Samamon; Gao, Lixin; Zink, Michael

    Lately researchers are looking at ways to reduce the delay on video playback through mechanisms like prefetching and caching for Video-on-Demand (VoD) services. The usage of prefetching and caching also has the potential to reduce the amount of network bandwidth usage, as most popular requests are served from a local cache rather than the server containing the original content. In this paper, we investigate the advantages of having such a prefetching and caching scheme for a free hosting service of professionally created video (movies and TV shows) named "hulu". We look into the advantages of using a prefetching scheme where the most popular videos of the week, as provided by the hulu website, are prefetched and compare this approach with a conventional LRU caching scheme with limited storage space and a combined scheme of prefetching and caching. Results from our measurement and analysis shows that employing a basic caching scheme at the proxy yields a hit ratio of up to 77.69%, but requires storage of about 236GB. Further analysis shows that a prefetching scheme where the top-100 popular videos of the week are downloaded to the proxy yields a hit ratio of 44% with a storage requirement of 10GB. A LRU caching scheme with a storage limitation of 20GB can achieve a hit ratio of 55% but downloads 4713 videos to achieve such high hit ratio compared to 100 videos in prefetching scheme, whereas a scheme with both prefetching and caching with the same storage yields a hit ratio of 59% with download requirement of 4439 videos. We find that employing a scheme of prefetching along with caching with trade-off on the storage will yield a better hit ratio and bandwidth saving than individual caching or prefetching schemes.

  5. Effectiveness of caching in a distributed digital library system

    DEFF Research Database (Denmark)

    Hollmann, J.; Ardø, Anders; Stenstrom, P.

    2007-01-01

    as manifested by gateways that implement the interfaces to the many fulltext archives. A central research question in this approach is: What is the nature of locality in the user access stream to such a digital library? Based on access logs that drive the simulations, it is shown that client-side caching can......Today independent publishers are offering digital libraries with fulltext archives. In an attempt to provide a single user-interface to a large set of archives, the studied Article-Database-Service offers a consolidated interface to a geographically distributed set of archives. While this approach...

  6. Ordering sparse matrices for cache-based systems

    International Nuclear Information System (INIS)

    Biswas, Rupak; Oliker, Leonid

    2001-01-01

    The Conjugate Gradient (CG) algorithm is the oldest and best-known Krylov subspace method used to solve sparse linear systems. Most of the coating-point operations within each CG iteration is spent performing sparse matrix-vector multiplication (SPMV). We examine how various ordering and partitioning strategies affect the performance of CG and SPMV when different programming paradigms are used on current commercial cache-based computers. However, a multithreaded implementation on the cacheless Cray MTA demonstrates high efficiency and scalability without any special ordering or partitioning

  7. Something different - caching applied to calculation of impedance matrix elements

    CSIR Research Space (South Africa)

    Lysko, AA

    2012-09-01

    Full Text Available of the multipliers, the approximating functions are used any required parameters, such as input impedance or gain pattern etc. The method is relatively straightforward but, especially for small to medium matrices, requires spending time on filling... of the computing the impedance matrix for the method of moments, or a similar method, such as boundary element method (BEM) [22], with the help of the flowchart shown in Figure 1. Input Parameters (a) Search the cached data for a match (b) A match found...

  8. A general approach for cache-oblivious range reporting and approximate range counting

    DEFF Research Database (Denmark)

    Afshani, Peyman; Hamilton, Chris; Zeh, Norbert

    2010-01-01

    We present cache-oblivious solutions to two important variants of range searching: range reporting and approximate range counting. Our main contribution is a general approach for constructing cache-oblivious data structures that provide relative (1+ε)-approximations for a general class of range c...

  9. Lack of caching of direct-seeded Douglas fir seeds by deer mice

    International Nuclear Information System (INIS)

    Sullivan, T.P.

    1978-01-01

    Seed caching by deer mice was investigated by radiotagging seeds in forest and clear-cut areas in coastal British Columbia. Deer mice tend to cache very few Douglas fir seeds in the fall when the seed is uniformly distributed and is at densities comparable with those used in direct-seeding programs. (author)

  10. Web Cache Prefetching as an Aspect: Towards a Dynamic-Weaving Based Solution

    DEFF Research Database (Denmark)

    Segura-Devillechaise, Marc; Menaud, Jean-Marc; Muller, Gilles

    2003-01-01

    Given the high proportion of HTTP traffic in the Internet, Web caches are crucial to reduce user access time, network latency, and bandwidth consumption. Prefetching in a Web cache can further enhance these benefits. For the best performance, however, the prefetching policy must match user and Web...

  11. Learning Automata Based Caching for Efficient Data Access in Delay Tolerant Networks

    Directory of Open Access Journals (Sweden)

    Zhenjie Ma

    2018-01-01

    Full Text Available Effective data access is one of the major challenges in Delay Tolerant Networks (DTNs that are characterized by intermittent network connectivity and unpredictable node mobility. Currently, different data caching schemes have been proposed to improve the performance of data access in DTNs. However, most existing data caching schemes perform poorly due to the lack of global network state information and the changing network topology in DTNs. In this paper, we propose a novel data caching scheme based on cooperative caching in DTNs, aiming at improving the successful rate of data access and reducing the data access delay. In the proposed scheme, learning automata are utilized to select a set of caching nodes as Caching Node Set (CNS in DTNs. Unlike the existing caching schemes failing to address the challenging characteristics of DTNs, our scheme is designed to automatically self-adjust to the changing network topology through the well-designed voting and updating processes. The proposed scheme improves the overall performance of data access in DTNs compared with the former caching schemes. The simulations verify the feasibility of our scheme and the improvements in performance.

  12. A Cache Considering Role-Based Access Control and Trust in Privilege Management Infrastructure

    Institute of Scientific and Technical Information of China (English)

    ZHANG Shaomin; WANG Baoyi; ZHOU Lihua

    2006-01-01

    PMI(privilege management infrastructure) is used to perform access control to resource in an E-commerce or E-government system. With the ever-increasing need for secure transaction, the need for systems that offer a wide variety of QoS (quality-of-service) features is also growing. In order to improve the QoS of PMI system, a cache based on RBAC(Role-based Access Control) and trust is proposed. Our system is realized based on Web service. How to design the cache based on RBAC and trust in the access control model is described in detail. The algorithm to query role permission in cache and to add records in cache is dealt with. The policy to update cache is introduced also.

  13. Single Carrier Cyclic Prefix-Assisted CDMA System with Frequency Domain Equalization for High Data Rate Transmission

    Directory of Open Access Journals (Sweden)

    Madhukumar A. S.

    2004-01-01

    Full Text Available Multiple-access interference and interfinger interference limit the capacity of conventional single-carrier DS-CDMA systems. Even though multicarrier CDMA posses the advantages of conventional CDMA and OFDM, it suffers from two major implementation difficulties such as peak-to-average power ratio and high sensitivity to frequency offset and RF phase noise. A novel approach based on single-carrier cyclic prefix-assisted CDMA has been proposed to overcome the disadvantages of single-carrier CDMA and multicarrier modulation. The usefulness of the proposed approach for high-speed packet access with simplified channel estimation procedures are investigated in this paper. The paper also proposes a data-dependent pilot structure for the downlink transmission of the proposed system for enhancing pilot-assisted channel estimation in frequency domain. The performance of the proposed pilot structure is compared against the data-independent common pilot structure. The proposed system is extensively simulated for different channel parameters with different channel estimation and equalization methods and the results are compared against conventional multicarrier CDMA systems with identical system specifications.

  14. Generic Database Cost Models for Hierarchical Memory Systems

    OpenAIRE

    Manegold, Stefan; Boncz, Peter; Kersten, Martin

    2002-01-01

    textabstractAccurate prediction of operator execution time is a prerequisite for database query optimization. Although extensively studied for conventional disk-based DBMSs, cost modeling in main-memory DBMSs is still an open issue. Recent database research has demonstrated that memory access is more and more becoming a significant---if not the major---cost component of database operations. If used properly, fast but small cache memories---usually organized in cascading hierarchy between CPU ...

  15. Broadcasted Location-Aware Data Cache for Vehicular Application

    Directory of Open Access Journals (Sweden)

    Fukuda Akira

    2007-01-01

    Full Text Available There has been increasing interest in the exploitation of advances in information technology, for example, mobile computing and wireless communications in ITS (intelligent transport systems. Classes of applications that can benefit from such an infrastructure include traffic information, roadside businesses, weather reports, entertainment, and so on. There are several wireless communication methods currently available that can be utilized for vehicular applications, such as cellular phone networks, DSRC (dedicated short-range communication, and digital broadcasting. While a cellular phone network is relatively slow and a DSRC has a very small communication area, one-segment digital terrestrial broadcasting service was launched in Japan in 2006, high-performance digital broadcasting for mobile hosts has been available recently. However, broadcast delivery methods have the drawback that clients need to wait for the required data items to appear on the broadcast channel. In this paper, we propose a new cache system to effectively prefetch and replace broadcast data using "scope" (an available area of location-dependent data and "mobility specification" (a schedule according to the direction in which a mobile host moves. We numerically evaluate the cache system on the model close to the traffic road environment, and implement the emulation system to evaluate this location-aware data delivery method for a concrete vehicular application that delivers geographic road map data to a car navigation system.

  16. Pattern recognition for cache management in distributed medical imaging environments.

    Science.gov (United States)

    Viana-Ferreira, Carlos; Ribeiro, Luís; Matos, Sérgio; Costa, Carlos

    2016-02-01

    Traditionally, medical imaging repositories have been supported by indoor infrastructures with huge operational costs. This paradigm is changing thanks to cloud outsourcing which not only brings technological advantages but also facilitates inter-institutional workflows. However, communication latency is one main problem in this kind of approaches, since we are dealing with tremendous volumes of data. To minimize the impact of this issue, cache and prefetching are commonly used. The effectiveness of these mechanisms is highly dependent on their capability of accurately selecting the objects that will be needed soon. This paper describes a pattern recognition system based on artificial neural networks with incremental learning to evaluate, from a set of usage pattern, which one fits the user behavior at a given time. The accuracy of the pattern recognition model in distinct training conditions was also evaluated. The solution was tested with a real-world dataset and a synthesized dataset, showing that incremental learning is advantageous. Even with very immature initial models, trained with just 1 week of data samples, the overall accuracy was very similar to the value obtained when using 75% of the long-term data for training the models. Preliminary results demonstrate an effective reduction in communication latency when using the proposed solution to feed a prefetching mechanism. The proposed approach is very interesting for cache replacement and prefetching policies due to the good results obtained since the first deployment moments.

  17. Broadcasted Location-Aware Data Cache for Vehicular Application

    Directory of Open Access Journals (Sweden)

    Kenya Sato

    2007-05-01

    Full Text Available There has been increasing interest in the exploitation of advances in information technology, for example, mobile computing and wireless communications in ITS (intelligent transport systems. Classes of applications that can benefit from such an infrastructure include traffic information, roadside businesses, weather reports, entertainment, and so on. There are several wireless communication methods currently available that can be utilized for vehicular applications, such as cellular phone networks, DSRC (dedicated short-range communication, and digital broadcasting. While a cellular phone network is relatively slow and a DSRC has a very small communication area, one-segment digital terrestrial broadcasting service was launched in Japan in 2006, high-performance digital broadcasting for mobile hosts has been available recently. However, broadcast delivery methods have the drawback that clients need to wait for the required data items to appear on the broadcast channel. In this paper, we propose a new cache system to effectively prefetch and replace broadcast data using “scope” (an available area of location-dependent data and “mobility specification” (a schedule according to the direction in which a mobile host moves. We numerically evaluate the cache system on the model close to the traffic road environment, and implement the emulation system to evaluate this location-aware data delivery method for a concrete vehicular application that delivers geographic road map data to a car navigation system.

  18. The future of memory

    Science.gov (United States)

    Marinella, M.

    In the not too distant future, the traditional memory and storage hierarchy of may be replaced by a single Storage Class Memory (SCM) device integrated on or near the logic processor. Traditional magnetic hard drives, NAND flash, DRAM, and higher level caches (L2 and up) will be replaced with a single high performance memory device. The Storage Class Memory paradigm will require high speed (read/write), excellent endurance (> 1012), nonvolatility (retention > 10 years), and low switching energies (memory (PCM). All of these devices show potential well beyond that of current flash technologies and research efforts are underway to improve the endurance, write speeds, and scalabilities to be on-par with DRAM. This progress has interesting implications for space electronics: each of these emerging device technologies show excellent resistance to the types of radiation typically found in space applications. Commercially developed, high density storage class memory-based systems may include a memory that is physically radiation hard, and suitable for space applications without major shielding efforts. This paper reviews the Storage Class Memory concept, emerging memory devices, and possible applicability to radiation hardened electronics for space.

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

    DEFF Research Database (Denmark)

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

    2014-01-01

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

  20. Novel dynamic caching for hierarchically distributed video-on-demand systems

    Science.gov (United States)

    Ogo, Kenta; Matsuda, Chikashi; Nishimura, Kazutoshi

    1998-02-01

    It is difficult to simultaneously serve the millions of video streams that will be needed in the age of 'Mega-Media' networks by using only one high-performance server. To distribute the service load, caching servers should be location near users. However, in previously proposed caching mechanisms, the grade of service depends on whether the data is already cached at a caching server. To make the caching servers transparent to the users, the ability to randomly access the large volume of data stored in the central server should be supported, and the operational functions of the provided service should not be narrowly restricted. We propose a mechanism for constructing a video-stream-caching server that is transparent to the users and that will always support all special playback functions for all available programs to all the contents with a latency of only 1 or 2 seconds. This mechanism uses Variable-sized-quantum-segment- caching technique derived from an analysis of the historical usage log data generated by a line-on-demand-type service experiment and based on the basic techniques used by a time- slot-based multiple-stream video-on-demand server.

  1. Adjustable Two-Tier Cache for IPTV Based on Segmented Streaming

    Directory of Open Access Journals (Sweden)

    Kai-Chun Liang

    2012-01-01

    Full Text Available Internet protocol TV (IPTV is a promising Internet killer application, which integrates video, voice, and data onto a single IP network, and offers viewers an innovative set of choices and control over their TV content. To provide high-quality IPTV services, an effective strategy is based on caching. This work proposes a segment-based two-tier caching approach, which divides each video into multiple segments to be cached. This approach also partitions the cache space into two layers, where the first layer mainly caches to-be-played segments and the second layer saves possibly played segments. As the segment access becomes frequent, the proposed approach enlarges the first layer and reduces the second layer, and vice versa. Because requested segments may not be accessed frequently, this work further designs an admission control mechanism to determine whether an incoming segment should be cached or not. The cache architecture takes forward/stop playback into account and may replace the unused segments under the interrupted playback. Finally, we conduct comprehensive simulation experiments to evaluate the performance of the proposed approach. The results show that our approach can yield higher hit ratio than previous work under various environmental parameters.

  2. Nature as a treasure map! Teaching geoscience with the help of earth caches?!

    Science.gov (United States)

    Zecha, Stefanie; Schiller, Thomas

    2015-04-01

    This presentation looks at how earth caches are influence the learning process in the field of geo science in non-formal education. The development of mobile technologies using Global Positioning System (GPS) data to point geographical location together with the evolving Web 2.0 supporting the creation and consumption of content, suggest a potential for collaborative informal learning linked to location. With the help of the GIS in smartphones you can go directly in nature, search for information by your smartphone, and learn something about nature. Earth caches are a very good opportunity, which are organized and supervised geocaches with special information about physical geography high lights. Interested people can inform themselves about aspects in geoscience area by earth caches. The main question of this presentation is how these caches are created in relation to learning processes. As is not possible, to analyze all existing earth caches, there was focus on Bavaria and a certain feature of earth caches. At the end the authors show limits and potentials for the use of earth caches and give some remark for the future.

  3. Explicit Content Caching at Mobile Edge Networks with Cross-Layer Sensing

    Science.gov (United States)

    Chen, Lingyu; Su, Youxing; Luo, Wenbin; Hong, Xuemin; Shi, Jianghong

    2018-01-01

    The deployment density and computational power of small base stations (BSs) are expected to increase significantly in the next generation mobile communication networks. These BSs form the mobile edge network, which is a pervasive and distributed infrastructure that can empower a variety of edge/fog computing applications. This paper proposes a novel edge-computing application called explicit caching, which stores selective contents at BSs and exposes such contents to local users for interactive browsing and download. We formulate the explicit caching problem as a joint content recommendation, caching, and delivery problem, which aims to maximize the expected user quality-of-experience (QoE) with varying degrees of cross-layer sensing capability. Optimal and effective heuristic algorithms are presented to solve the problem. The theoretical performance bounds of the explicit caching system are derived in simplified scenarios. The impacts of cache storage space, BS backhaul capacity, cross-layer information, and user mobility on the system performance are simulated and discussed in realistic scenarios. Results suggest that, compared with conventional implicit caching schemes, explicit caching can better exploit the mobile edge network infrastructure for personalized content dissemination. PMID:29565313

  4. Explicit Content Caching at Mobile Edge Networks with Cross-Layer Sensing.

    Science.gov (United States)

    Chen, Lingyu; Su, Youxing; Luo, Wenbin; Hong, Xuemin; Shi, Jianghong

    2018-03-22

    The deployment density and computational power of small base stations (BSs) are expected to increase significantly in the next generation mobile communication networks. These BSs form the mobile edge network, which is a pervasive and distributed infrastructure that can empower a variety of edge/fog computing applications. This paper proposes a novel edge-computing application called explicit caching, which stores selective contents at BSs and exposes such contents to local users for interactive browsing and download. We formulate the explicit caching problem as a joint content recommendation, caching, and delivery problem, which aims to maximize the expected user quality-of-experience (QoE) with varying degrees of cross-layer sensing capability. Optimal and effective heuristic algorithms are presented to solve the problem. The theoretical performance bounds of the explicit caching system are derived in simplified scenarios. The impacts of cache storage space, BS backhaul capacity, cross-layer information, and user mobility on the system performance are simulated and discussed in realistic scenarios. Results suggest that, compared with conventional implicit caching schemes, explicit caching can better exploit the mobile edge network infrastructure for personalized content dissemination.

  5. Value-Based Caching in Information-Centric Wireless Body Area Networks

    Directory of Open Access Journals (Sweden)

    Fadi M. Al-Turjman

    2017-01-01

    Full Text Available We propose a resilient cache replacement approach based on a Value of sensed Information (VoI policy. To resolve and fetch content when the origin is not available due to isolated in-network nodes (fragmentation and harsh operational conditions, we exploit a content caching approach. Our approach depends on four functional parameters in sensory Wireless Body Area Networks (WBANs. These four parameters are: age of data based on periodic request, popularity of on-demand requests, communication interference cost, and the duration for which the sensor node is required to operate in active mode to capture the sensed readings. These parameters are considered together to assign a value to the cached data to retain the most valuable information in the cache for prolonged time periods. The higher the value, the longer the duration for which the data will be retained in the cache. This caching strategy provides significant availability for most valuable and difficult to retrieve data in the WBANs. Extensive simulations are performed to compare the proposed scheme against other significant caching schemes in the literature while varying critical aspects in WBANs (e.g., data popularity, cache size, publisher load, connectivity-degree, and severe probabilities of node failures. These simulation results indicate that the proposed VoI-based approach is a valid tool for the retrieval of cached content in disruptive and challenging scenarios, such as the one experienced in WBANs, since it allows the retrieval of content for a long period even while experiencing severe in-network node failures.

  6. Applying Data Mining Techniques to Improve Information Security in the Cloud: A Single Cache System Approach

    OpenAIRE

    Amany AlShawi

    2016-01-01

    Presently, the popularity of cloud computing is gradually increasing day by day. The purpose of this research was to enhance the security of the cloud using techniques such as data mining with specific reference to the single cache system. From the findings of the research, it was observed that the security in the cloud could be enhanced with the single cache system. For future purposes, an Apriori algorithm can be applied to the single cache system. This can be applied by all cloud providers...

  7. dCache, towards Federated Identities & Anonymized Delegation

    Science.gov (United States)

    Ashish, A.; Millar, AP; Mkrtchyan, T.; Fuhrmann, P.; Behrmann, G.; Sahakyan, M.; Adeyemi, O. S.; Starek, J.; Litvintsev, D.; Rossi, A.

    2017-10-01

    For over a decade, dCache has relied on the authentication and authorization infrastructure (AAI) offered by VOMS, Kerberos, Xrootd etc. Although the established infrastructure has worked well and provided sufficient security, the implementation of procedures and the underlying software is often seen as a burden, especially by smaller communities trying to adopt existing HEP software stacks [1]. Moreover, scientists are increasingly dependent on service portals for data access [2]. In this paper, we describe how federated identity management systems can facilitate the transition from traditional AAI infrastructure to novel solutions like OpenID Connect. We investigate the advantages offered by OpenID Connect in regards to ‘delegation of authentication’ and ‘credential delegation for offline access’. Additionally, we demonstrate how macaroons can provide a more fine-granular authorization mechanism that supports anonymized delegation.

  8. Geometric Algorithms for Private-Cache Chip Multiprocessors

    DEFF Research Database (Denmark)

    Ajwani, Deepak; Sitchinava, Nodari; Zeh, Norbert

    2010-01-01

    -D convex hulls. These results are obtained by analyzing adaptations of either the PEM merge sort algorithm or PRAM algorithms. For the second group of problems—orthogonal line segment intersection reporting, batched range reporting, and related problems—more effort is required. What distinguishes......We study techniques for obtaining efficient algorithms for geometric problems on private-cache chip multiprocessors. We show how to obtain optimal algorithms for interval stabbing counting, 1-D range counting, weighted 2-D dominance counting, and for computing 3-D maxima, 2-D lower envelopes, and 2...... these problems from the ones in the previous group is the variable output size, which requires I/O-efficient load balancing strategies based on the contribution of the individual input elements to the output size. To obtain nearly optimal algorithms for these problems, we introduce a parallel distribution...

  9. Cooperative Coding and Caching for Streaming Data in Multihop Wireless Networks

    Directory of Open Access Journals (Sweden)

    Dan Wang

    2010-01-01

    Full Text Available This paper studies the distributed caching managements for the current flourish of the streaming applications in multihop wireless networks. Many caching managements to date use randomized network coding approach, which provides an elegant solution for ubiquitous data accesses in such systems. However, the encoding, essentially a combination operation, makes the coded data difficult to be changed. In particular, to accommodate new data, the system may have to first decode all the combined data segments, remove some unimportant ones, and then reencode the data segments again. This procedure is clearly expensive for continuously evolving data storage. As such, we introduce a novel Cooperative Coding and Caching (C3 scheme, which allows decoding-free data removal through a triangle-like codeword organization. Its decoding performance is very close to the conventional network coding with only a sublinear overhead. Our scheme offers a promising solution to the caching management for streaming data.

  10. Researching of Covert Timing Channels Based on HTTP Cache Headers in Web API

    Directory of Open Access Journals (Sweden)

    Denis Nikolaevich Kolegov

    2015-12-01

    Full Text Available In this paper, it is shown how covert timing channels based on HTTP cache headers can be implemented using different Web API of Google Drive, Dropbox and Facebook  Internet services.

  11. A Novel Architecture of Metadata Management System Based on Intelligent Cache

    Institute of Scientific and Technical Information of China (English)

    SONG Baoyan; ZHAO Hongwei; WANG Yan; GAO Nan; XU Jin

    2006-01-01

    This paper introduces a novel architecture of metadata management system based on intelligent cache called Metadata Intelligent Cache Controller (MICC). By using an intelligent cache to control the metadata system, MICC can deal with different scenarios such as splitting and merging of queries into sub-queries for available metadata sets in local, in order to reduce access time of remote queries. Application can find results patially from local cache and the remaining portion of the metadata that can be fetched from remote locations. Using the existing metadata, it can not only enhance the fault tolerance and load balancing of system effectively, but also improve the efficiency of access while ensuring the access quality.

  12. dCache data storage system implementations at a Tier-2 centre

    Energy Technology Data Exchange (ETDEWEB)

    Tsigenov, Oleg; Nowack, Andreas; Kress, Thomas [III. Physikalisches Institut B, RWTH Aachen (Germany)

    2009-07-01

    The experimental high energy physics groups of the RWTH Aachen University operate one of the largest Grid Tier-2 sites in the world and offer more than 2000 modern CPU cores and about 550 TB of disk space mainly to the CMS experiment and to a lesser extent to the Auger and Icecube collaborations.Running such a large data cluster requires a flexible storage system with high performance. We use dCache for this purpose and are integrated into the dCache support team to the benefit of the German Grid sites. Recently, a storage pre-production cluster has been built to study the setup and the behavior of novel dCache features within Chimera without interfering with the production system. This talk gives an overview about the practical experience gained with dCache on both the production and the testbed cluster and discusses future plans.

  13. Optimal Replacement Policies for Non-Uniform Cache Objects with Optional Eviction

    National Research Council Canada - National Science Library

    Bahat, Omri; Makowski, Armand M

    2002-01-01

    .... However, since the introduction of optimal replacement policies for conventional caching, the problem of finding optimal replacement policies under the factors indicated has not been studied in any systematic manner...

  14. Cooperative Coding and Caching for Streaming Data in Multihop Wireless Networks

    Directory of Open Access Journals (Sweden)

    Liu Jiangchuan

    2010-01-01

    Full Text Available This paper studies the distributed caching managements for the current flourish of the streaming applications in multihop wireless networks. Many caching managements to date use randomized network coding approach, which provides an elegant solution for ubiquitous data accesses in such systems. However, the encoding, essentially a combination operation, makes the coded data difficult to be changed. In particular, to accommodate new data, the system may have to first decode all the combined data segments, remove some unimportant ones, and then reencode the data segments again. This procedure is clearly expensive for continuously evolving data storage. As such, we introduce a novel Cooperative Coding and Caching ( scheme, which allows decoding-free data removal through a triangle-like codeword organization. Its decoding performance is very close to the conventional network coding with only a sublinear overhead. Our scheme offers a promising solution to the caching management for streaming data.

  15. Applying Data Mining Techniques to Improve Information Security in the Cloud: A Single Cache System Approach

    Directory of Open Access Journals (Sweden)

    Amany AlShawi

    2016-01-01

    Full Text Available Presently, the popularity of cloud computing is gradually increasing day by day. The purpose of this research was to enhance the security of the cloud using techniques such as data mining with specific reference to the single cache system. From the findings of the research, it was observed that the security in the cloud could be enhanced with the single cache system. For future purposes, an Apriori algorithm can be applied to the single cache system. This can be applied by all cloud providers, vendors, data distributors, and others. Further, data objects entered into the single cache system can be extended into 12 components. Database and SPSS modelers can be used to implement the same.

  16. Content Delivery in Fog-Aided Small-Cell Systems with Offline and Online Caching: An Information—Theoretic Analysis

    Directory of Open Access Journals (Sweden)

    Seyyed Mohammadreza Azimi

    2017-07-01

    Full Text Available The storage of frequently requested multimedia content at small-cell base stations (BSs can reduce the load of macro-BSs without relying on high-speed backhaul links. In this work, the optimal operation of a system consisting of a cache-aided small-cell BS and a macro-BS is investigated for both offline and online caching settings. In particular, a binary fading one-sided interference channel is considered in which the small-cell BS, whose transmission is interfered by the macro-BS, has a limited-capacity cache. The delivery time per bit (DTB is adopted as a measure of the coding latency, that is, the duration of the transmission block, required for reliable delivery. For offline caching, assuming a static set of popular contents, the minimum achievable DTB is characterized through information-theoretic achievability and converse arguments as a function of the cache capacity and of the capacity of the backhaul link connecting cloud and small-cell BS. For online caching, under a time-varying set of popular contents, the long-term (average DTB is evaluated for both proactive and reactive caching policies. Furthermore, a converse argument is developed to characterize the minimum achievable long-term DTB for online caching in terms of the minimum achievable DTB for offline caching. The performance of both online and offline caching is finally compared using numerical results.

  17. A Survey on Mobile Edge Networks: Convergence of Computing, Caching and Communications

    OpenAIRE

    Wang, Shuo; Zhang, Xing; Zhang, Yan; Wang, Lin; Yang, Juwo; Wang, Wenbo

    2017-01-01

    As the explosive growth of smart devices and the advent of many new applications, traffic volume has been growing exponentially. The traditional centralized network architecture cannot accommodate such user demands due to heavy burden on the backhaul links and long latency. Therefore, new architectures which bring network functions and contents to the network edge are proposed, i.e., mobile edge computing and caching. Mobile edge networks provide cloud computing and caching capabilities at th...

  18. dCache: Big Data storage for HEP communities and beyond

    International Nuclear Information System (INIS)

    Millar, A P; Bernardt, C; Fuhrmann, P; Mkrtchyan, T; Petersen, A; Schwank, K; Behrmann, G; Litvintsev, D; Rossi, A

    2014-01-01

    With over ten years in production use dCache data storage system has evolved to match ever changing lansdcape of continually evolving storage technologies with new solutions to both existing problems and new challenges. In this paper, we present three areas of innovation in dCache: providing efficient access to data with NFS v4.1 pNFS, adoption of CDMI and WebDAV as an alternative to SRM for managing data, and integration with alternative authentication mechanisms.

  19. LPPS: A Distributed Cache Pushing Based K-Anonymity Location Privacy Preserving Scheme

    Directory of Open Access Journals (Sweden)

    Ming Chen

    2016-01-01

    Full Text Available Recent years have witnessed the rapid growth of location-based services (LBSs for mobile social network applications. To enable location-based services, mobile users are required to report their location information to the LBS servers and receive answers of location-based queries. Location privacy leak happens when such servers are compromised, which has been a primary concern for information security. To address this issue, we propose the Location Privacy Preservation Scheme (LPPS based on distributed cache pushing. Unlike existing solutions, LPPS deploys distributed cache proxies to cover users mostly visited locations and proactively push cache content to mobile users, which can reduce the risk of leaking users’ location information. The proposed LPPS includes three major process. First, we propose an algorithm to find the optimal deployment of proxies to cover popular locations. Second, we present cache strategies for location-based queries based on the Markov chain model and propose update and replacement strategies for cache content maintenance. Third, we introduce a privacy protection scheme which is proved to achieve k-anonymity guarantee for location-based services. Extensive experiments illustrate that the proposed LPPS achieves decent service coverage ratio and cache hit ratio with lower communication overhead compared to existing solutions.

  20. Embedded Memory Hierarchy Exploration Based on Magnetic Random Access Memory

    Directory of Open Access Journals (Sweden)

    Luís Vitório Cargnini

    2014-08-01

    Full Text Available Static random access memory (SRAM is the most commonly employed semiconductor in the design of on-chip processor memory. However, it is unlikely that the SRAM technology will have a cell size that will continue to scale below 45 nm, due to the leakage current that is caused by the quantum tunneling effect. Magnetic random access memory (MRAM is a candidate technology to replace SRAM, assuming appropriate dimensioning given an operating threshold voltage. The write current of spin transfer torque (STT-MRAM is a known limitation; however, this has been recently mitigated by leveraging perpendicular magnetic tunneling junctions. In this article, we present a comprehensive comparison of spin transfer torque-MRAM (STT-MRAM and SRAM cache set banks. The non-volatility of STT-MRAM allows the definition of new instant on/off policies and leakage current optimizations. Through our experiments, we demonstrate that STT-MRAM is a candidate for the memory hierarchy of embedded systems, due to the higher densities and reduced leakage of MRAM.We demonstrate that adopting STT-MRAM in L1 and L2 caches mitigates the impact of higher write latencies and increased current draw due to the use of MRAM. With the correct system-on-chip (SoC design, we believe that STT-MRAM is a viable alternative to SRAM, which minimizes leakage current and the total power consumed by the SoC.

  1. Efficient Numeric and Geometric Computations using Heterogeneous Shared Memory Architectures

    Science.gov (United States)

    2017-10-04

    to the memory architectures of CPUs and GPUs to obtain good performance and result in good memory performance using cache management. These methods ...Accomplishments: The PI and students has developed new methods for path and ray tracing and their Report Date: 14-Oct-2017 INVESTIGATOR(S): Phone...The efficiency of our method makes it a good candidate for forming hybrid schemes with wave-based models. One possibility is to couple the ray curve

  2. Software Prefetching for Indirect Memory Accesses

    OpenAIRE

    Ainsworth, Sam; Jones, Timothy

    2017-01-01

    Many modern data processing and HPC workloads are heavily memory-latency bound. A tempting proposition to solve this is software prefetching, where special non-blocking loads are used to bring data into the cache hierarchy just before being required. However, these are difficult to insert to effectively improve performance, and techniques for automatic insertion are currently limited. This paper develops a novel compiler pass to automatically generate software prefetches for indirect mem...

  3. Data Locality via Coordinated Caching for Distributed Processing

    Science.gov (United States)

    Fischer, M.; Kuehn, E.; Giffels, M.; Jung, C.

    2016-10-01

    To enable data locality, we have developed an approach of adding coordinated caches to existing compute clusters. Since the data stored locally is volatile and selected dynamically, only a fraction of local storage space is required. Our approach allows to freely select the degree at which data locality is provided. It may be used to work in conjunction with large network bandwidths, providing only highly used data to reduce peak loads. Alternatively, local storage may be scaled up to perform data analysis even with low network bandwidth. To prove the applicability of our approach, we have developed a prototype implementing all required functionality. It integrates seamlessly into batch systems, requiring practically no adjustments by users. We have now been actively using this prototype on a test cluster for HEP analyses. Specifically, it has been integral to our jet energy calibration analyses for CMS during run 2. The system has proven to be easily usable, while providing substantial performance improvements. Since confirming the applicability for our use case, we have investigated the design in a more general way. Simulations show that many infrastructure setups can benefit from our approach. For example, it may enable us to dynamically provide data locality in opportunistic cloud resources. The experience we have gained from our prototype enables us to realistically assess the feasibility for general production use.

  4. Energy-Efficient Caching for Mobile Edge Computing in 5G Networks

    Directory of Open Access Journals (Sweden)

    Zhaohui Luo

    2017-05-01

    Full Text Available Mobile Edge Computing (MEC, which is considered a promising and emerging paradigm to provide caching capabilities in proximity to mobile devices in 5G networks, enables fast, popular content delivery of delay-sensitive applications at the backhaul capacity of limited mobile networks. Most existing studies focus on cache allocation, mechanism design and coding design for caching. However, grid power supply with fixed power uninterruptedly in support of a MEC server (MECS is costly and even infeasible, especially when the load changes dynamically over time. In this paper, we investigate the energy consumption of the MECS problem in cellular networks. Given the average download latency constraints, we take the MECS’s energy consumption, backhaul capacities and content popularity distributions into account and formulate a joint optimization framework to minimize the energy consumption of the system. As a complicated joint optimization problem, we apply a genetic algorithm to solve it. Simulation results show that the proposed solution can effectively determine the near-optimal caching placement to obtain better performance in terms of energy efficiency gains compared with conventional caching placement strategies. In particular, it is shown that the proposed scheme can significantly reduce the joint cost when backhaul capacity is low.

  5. Exact Analysis of the Cache Behavior of Nested Loops

    National Research Council Canada - National Science Library

    Chatterjee, Siddhartha; Parker, Erin; Hanlon, Philip J; Lebeck, Alvin R

    2001-01-01

    The authors develop from first principles an exact model of the behavior of loop nests executing in a memory hierarchy by using a nontraditional classification of misses that has the key property of composability...

  6. Elastic pointer directory organization for scalable shared memory multiprocessors

    Institute of Scientific and Technical Information of China (English)

    Yuhang Liu; Mingfa Zhu; Limin Xiao

    2014-01-01

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

  7. Worst-case execution time analysis-driven object cache design

    DEFF Research Database (Denmark)

    Huber, Benedikt; Puffitsch, Wolfgang; Schoeberl, Martin

    2012-01-01

    result in a WCET analysis‐friendly design. Aiming for a time‐predictable design, we therefore propose to employ WCET analysis techniques for the design space exploration of processor architectures. We evaluated different object cache configurations using static analysis techniques. The number of field......Hard real‐time systems need a time‐predictable computing platform to enable static worst‐case execution time (WCET) analysis. All performance‐enhancing features need to be WCET analyzable. However, standard data caches containing heap‐allocated data are very hard to analyze statically....... In this paper we explore a new object cache design, which is driven by the capabilities of static WCET analysis. Simulations of standard benchmarks estimating the expected average case performance usually drive computer architecture design. The design decisions derived from this methodology do not necessarily...

  8. 5G Network Communication, Caching, and Computing Algorithms Based on the Two‐Tier Game Model

    Directory of Open Access Journals (Sweden)

    Sungwook Kim

    2018-02-01

    Full Text Available In this study, we developed hybrid control algorithms in smart base stations (SBSs along with devised communication, caching, and computing techniques. In the proposed scheme, SBSs are equipped with computing power and data storage to collectively offload the computation from mobile user equipment and to cache the data from clouds. To combine in a refined manner the communication, caching, and computing algorithms, game theory is adopted to characterize competitive and cooperative interactions. The main contribution of our proposed scheme is to illuminate the ultimate synergy behind a fully integrated approach, while providing excellent adaptability and flexibility to satisfy the different performance requirements. Simulation results demonstrate that the proposed approach can outperform existing schemes by approximately 5% to 15% in terms of bandwidth utilization, access delay, and system throughput.

  9. Killing and caching of an adult White-tailed deer, Odocoileus virginianus, by a single Gray Wolf, Canis lupus

    Science.gov (United States)

    Nelson, Michael E.

    2011-01-01

    A single Gray Wolf (Canis lupus) killed an adult male White-tailed Deer (Odocoileus virginianus) and cached the intact carcass in 76 cm of snow. The carcass was revisited and entirely consumed between four and seven days later. This is the first recorded observation of a Gray Wolf caching an entire adult deer.

  10. Spin-transfer torque magnetoresistive random-access memory technologies for normally off computing (invited)

    International Nuclear Information System (INIS)

    Ando, K.; Yuasa, S.; Fujita, S.; Ito, J.; Yoda, H.; Suzuki, Y.; Nakatani, Y.; Miyazaki, T.

    2014-01-01

    Most parts of present computer systems are made of volatile devices, and the power to supply them to avoid information loss causes huge energy losses. We can eliminate this meaningless energy loss by utilizing the non-volatile function of advanced spin-transfer torque magnetoresistive random-access memory (STT-MRAM) technology and create a new type of computer, i.e., normally off computers. Critical tasks to achieve normally off computers are implementations of STT-MRAM technologies in the main memory and low-level cache memories. STT-MRAM technology for applications to the main memory has been successfully developed by using perpendicular STT-MRAMs, and faster STT-MRAM technologies for applications to the cache memory are now being developed. The present status of STT-MRAMs and challenges that remain for normally off computers are discussed

  11. Decision-cache based XACML authorisation and anonymisation for XML documents

    OpenAIRE

    Ulltveit-Moe, Nils; Oleshchuk, Vladimir A

    2012-01-01

    Author's version of an article in the journal: Computer Standards and Interfaces. Also available from the publisher at: http://dx.doi.org/10.1016/j.csi.2011.10.007 This paper describes a decision cache for the eXtensible Access Control Markup Language (XACML) that supports fine-grained authorisation and anonymisation of XML based messages and documents down to XML attribute and element level. The decision cache is implemented as an XACML obligation service, where a specification of the XML...

  12. Consistencia de ejecución: una propuesta no cache coherente

    OpenAIRE

    García, Rafael B.; Ardenghi, Jorge Raúl

    2005-01-01

    La presencia de uno o varios niveles de memoria cache en los procesadores modernos, cuyo objetivo es reducir el tiempo efectivo de acceso a memoria, adquiere especial relevancia en un ambiente multiprocesador del tipo DSM dado el mucho mayor costo de las referencias a memoria en módulos remotos. Claramente, el protocolo de coherencia de cache debe responder al modelo de consistencia de memoria adoptado. El modelo secuencial SC, aceptado generalmente como el más natural, junto a una serie de m...

  13. Security in the CernVM File System and the Frontier Distributed Database Caching System

    International Nuclear Information System (INIS)

    Dykstra, D; Blomer, J

    2014-01-01

    Both the CernVM File System (CVMFS) and the Frontier Distributed Database Caching System (Frontier) distribute centrally updated data worldwide for LHC experiments using http proxy caches. Neither system provides privacy or access control on reading the data, but both control access to updates of the data and can guarantee the authenticity and integrity of the data transferred to clients over the internet. CVMFS has since its early days required digital signatures and secure hashes on all distributed data, and recently Frontier has added X.509-based authenticity and integrity checking. In this paper we detail and compare the security models of CVMFS and Frontier.

  14. Security in the CernVM File System and the Frontier Distributed Database Caching System

    Science.gov (United States)

    Dykstra, D.; Blomer, J.

    2014-06-01

    Both the CernVM File System (CVMFS) and the Frontier Distributed Database Caching System (Frontier) distribute centrally updated data worldwide for LHC experiments using http proxy caches. Neither system provides privacy or access control on reading the data, but both control access to updates of the data and can guarantee the authenticity and integrity of the data transferred to clients over the internet. CVMFS has since its early days required digital signatures and secure hashes on all distributed data, and recently Frontier has added X.509-based authenticity and integrity checking. In this paper we detail and compare the security models of CVMFS and Frontier.

  15. Using XRootD to provide caches for CernVM-FS

    CERN Document Server

    Domenighini, Matteo

    2017-01-01

    CernVM-FS recently added the possibility of using plugin for cache management. In order to investigate the capabilities and limits of such possibility, an XRootD plugin was written and benchmarked; as a byproduct, a POSIX plugin was also generated. The tests revealed that the plugin interface introduces no signicant performance over- head; moreover, the XRootD plugin performance was discovered to be worse than the ones of the built-in cache manager and the POSIX plugin. Further test of the XRootD component revealed that its per- formance is dependent on the server disk speed.

  16. In-memory interconnect protocol configuration registers

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Kevin Y.; Roberts, David A.

    2017-09-19

    Systems, apparatuses, and methods for moving the interconnect protocol configuration registers into the main memory space of a node. The region of memory used for storing the interconnect protocol configuration registers may also be made cacheable to reduce the latency of accesses to the interconnect protocol configuration registers. Interconnect protocol configuration registers which are used during a startup routine may be prefetched into the host's cache to make the startup routine more efficient. The interconnect protocol configuration registers for various interconnect protocols may include one or more of device capability tables, memory-side statistics (e.g., to support two-level memory data mapping decisions), advanced memory and interconnect features such as repair resources and routing tables, prefetching hints, error correcting code (ECC) bits, lists of device capabilities, set and store base address, capability, device ID, status, configuration, capabilities, and other settings.

  17. In-memory interconnect protocol configuration registers

    Science.gov (United States)

    Cheng, Kevin Y.; Roberts, David A.

    2017-09-19

    Systems, apparatuses, and methods for moving the interconnect protocol configuration registers into the main memory space of a node. The region of memory used for storing the interconnect protocol configuration registers may also be made cacheable to reduce the latency of accesses to the interconnect protocol configuration registers. Interconnect protocol configuration registers which are used during a startup routine may be prefetched into the host's cache to make the startup routine more efficient. The interconnect protocol configuration registers for various interconnect protocols may include one or more of device capability tables, memory-side statistics (e.g., to support two-level memory data mapping decisions), advanced memory and interconnect features such as repair resources and routing tables, prefetching hints, error correcting code (ECC) bits, lists of device capabilities, set and store base address, capability, device ID, status, configuration, capabilities, and other settings.

  18. 3D-LIN: A Configurable Low-Latency Interconnect for Multi-Core Clusters with 3D Stacked L1 Memory

    OpenAIRE

    Beanato, Giulia; Loi, Igor; De Micheli, Giovanni; Leblebici, Yusuf; Benini, Luca

    2012-01-01

    Shared L1 memories are of interest for tightly- coupled processor clusters in programmable accelerators as they provide a convenient shared memory abstraction while avoiding cache coherence overheads. The performance of a shared-L1 memory critically depends on the architecture of the low-latency interconnect between processors and memory banks, which needs to provide ultra-fast access to the largest possible L1 working set. The advent of 3D technology provides new opportunities to improve the...

  19. No evidence for memory interference across sessions in food hoarding marsh tits Poecile palustris under laboratory conditions.

    Science.gov (United States)

    Urhan, A Utku; Brodin, Anders

    2015-05-01

    Scatter hoarding birds are known for their accurate spatial memory. In a previous experiment, we tested the retrieval accuracy in marsh tits in a typical laboratory set-up for this species. We also tested the performance of humans in this experimental set-up. Somewhat unexpectedly, humans performed much better than marsh tits. In the first five attempts, humans relocated almost 90 % of the caches they had hidden 5 h earlier. Marsh tits only relocated 25 % in the first five attempts and just above 40 % in the first ten attempts. Typically, in this type of experiment, the birds will be caching and retrieving many times in the same sites in the same experimental room. This is very different from the conditions in nature where hoarding parids only cache once in a caching site. Hence, it is possible that memories from previous sessions will disturb the formation of new memories. If there is such proactive interference, the prediction is that success should decay over sessions. Here, we have designed an experiment to investigate whether there is such memory interference in this type of experiment. We allowed marsh tits and humans to cache and retrieve in three repeated sessions without prior experience of the arena. The performance did not change over sessions, and on average, marsh tits correctly visited around 25 % of the caches in the first five attempts. The corresponding success in humans was constant across sessions, and it was around 90 % on average. We conclude that the somewhat poor performance of the marsh tits did not depend on proactive memory interference. We also discuss other possible reasons for why marsh tits in general do not perform better in laboratory experiments.

  20. What happens during a Join? - Dissecting CPU and Memory Optimization Effects

    NARCIS (Netherlands)

    S. Manegold (Stefan); P.A. Boncz (Peter); M.L. Kersten (Martin)

    2000-01-01

    textabstractPerformance of modern hardware increasingly depends on proper utilization of both the memory cache hierarchy and parallel execution possibilities in todays super-scalar CPUs. Recent database research has demonstrated that database system performance severely suffers from poor utilization

  1. External Memory Algorithms for Diameter and All-Pair Shortest-Paths on Sparse Graphs

    DEFF Research Database (Denmark)

    Arge, Lars; Meyer, Ulrich; Toma, Laura

    2004-01-01

    We present several new external-memory algorithms for finding all-pairs shortest paths in a V -node, Eedge undirected graph. For all-pairs shortest paths and diameter in unweighted undirected graphs we present cache-oblivious algorithms with O(V · E B logM B E B) I/Os, where B is the block-size a...

  2. Exploitation of pocket gophers and their food caches by grizzly bears

    Science.gov (United States)

    Mattson, D.J.

    2004-01-01

    I investigated the exploitation of pocket gophers (Thomomys talpoides) by grizzly bears (Ursus arctos horribilis) in the Yellowstone region of the United States with the use of data collected during a study of radiomarked bears in 1977-1992. My analysis focused on the importance of pocket gophers as a source of energy and nutrients, effects of weather and site features, and importance of pocket gophers to grizzly bears in the western contiguous United States prior to historical extirpations. Pocket gophers and their food caches were infrequent in grizzly bear feces, although foraging for pocket gophers accounted for about 20-25% of all grizzly bear feeding activity during April and May. Compared with roots individually excavated by bears, pocket gopher food caches were less digestible but more easily dug out. Exploitation of gopher food caches by grizzly bears was highly sensitive to site and weather conditions and peaked during and shortly after snowmelt. This peak coincided with maximum success by bears in finding pocket gopher food caches. Exploitation was most frequent and extensive on gently sloping nonforested sites with abundant spring beauty (Claytonia lanceolata) and yampah (Perdieridia gairdneri). Pocket gophers are rare in forests, and spring beauty and yampah roots are known to be important foods of both grizzly bears and burrowing rodents. Although grizzly bears commonly exploit pocket gophers only in the Yellowstone region, this behavior was probably widespread in mountainous areas of the western contiguous United States prior to extirpations of grizzly bears within the last 150 years.

  3. Turbidity and Total Suspended Solids on the Lower Cache River Watershed, AR.

    Science.gov (United States)

    Rosado-Berrios, Carlos A; Bouldin, Jennifer L

    2016-06-01

    The Cache River Watershed (CRW) in Arkansas is part of one of the largest remaining bottomland hardwood forests in the US. Although wetlands are known to improve water quality, the Cache River is listed as impaired due to sedimentation and turbidity. This study measured turbidity and total suspended solids (TSS) in seven sites of the lower CRW; six sites were located on the Bayou DeView tributary of the Cache River. Turbidity and TSS levels ranged from 1.21 to 896 NTU, and 0.17 to 386.33 mg/L respectively and had an increasing trend over the 3-year study. However, a decreasing trend from upstream to downstream in the Bayou DeView tributary was noted. Sediment loading calculated from high precipitation events and mean TSS values indicate that contributions from the Cache River main channel was approximately 6.6 times greater than contributions from Bayou DeView. Land use surrounding this river channel affects water quality as wetlands provide a filter for sediments in the Bayou DeView channel.

  4. On-chip COMA cache-coherence protocol for microgrids of microthreaded cores

    NARCIS (Netherlands)

    Zhang, L.; Jesshope, C.

    2008-01-01

    This paper describes an on-chip COMA cache coherency protocol to support the microthread model of concurrent program composition. The model gives a sound basis for building multi-core computers as it captures concurrency, abstracts communication and identifies resources, such as processor groups

  5. CACHE: an extended BASIC program which computes the performance of shell and tube heat exchangers

    International Nuclear Information System (INIS)

    Tallackson, J.R.

    1976-03-01

    An extended BASIC program, CACHE, has been written to calculate steady state heat exchange rates in the core auxiliary heat exchangers, (CAHE), designed to remove afterheat from High-Temperature Gas-Cooled Reactors (HTGR). Computationally, these are unbaffled counterflow shell and tube heat exchangers. The computational method is straightforward. The exchanger is subdivided into a user-selected number of lengthwise segments; heat exchange in each segment is calculated in sequence and summed. The program takes the temperature dependencies of all thermal conductivities, viscosities and heat capacities into account providing these are expressed algebraically. CACHE is easily adapted to compute steady state heat exchange rates in any unbaffled counterflow exchanger. As now used, CACHE calculates heat removal by liquid weight from high-temperature helium and helium mixed with nitrogen, oxygen and carbon monoxide. A second program, FULTN, is described. FULTN computes the geometrical parameters required as input to CACHE. As reported herein, FULTN computes the internal dimensions of the Fulton Station CAHE. The two programs are chained to operate as one. Complete user information is supplied. The basic equations, variable lists, annotated program lists, and sample outputs with explanatory notes are included

  6. OneService - Generic Cache Aggregator Framework for Service Depended Cloud Applications

    NARCIS (Netherlands)

    Tekinerdogan, B.; Oral, O.A.

    2017-01-01

    Current big data cloud systems often use different data migration strategies from providers to customers. This often results in increased bandwidth usage and herewith a decrease of the performance. To enhance the performance often caching mechanisms are adopted. However, the implementations of these

  7. Delivery Time Minimization in Edge Caching: Synergistic Benefits of Subspace Alignment and Zero Forcing

    KAUST Repository

    Kakar, Jaber; Alameer, Alaa; Chaaban, Anas; Sezgin, Aydin; Paulraj, Arogyaswami

    2017-01-01

    the fundamental limits of a cache-aided wireless network consisting of one central base station, $M$ transceivers and $K$ receivers from a latency-centric perspective. We use the normalized delivery time (NDT) to capture the per-bit latency for the worst-case file

  8. Randomized Caches Can Be Pretty Useful to Hard Real-Time Systems

    Directory of Open Access Journals (Sweden)

    Enrico Mezzetti

    2015-03-01

    Full Text Available Cache randomization per se, and its viability for probabilistic timing analysis (PTA of critical real-time systems, are receiving increasingly close attention from the scientific community and the industrial practitioners. In fact, the very notion of introducing randomness and probabilities in time-critical systems has caused strenuous debates owing to the apparent clash that this idea has with the strictly deterministic view traditionally held for those systems. A paper recently appeared in LITES (Reineke, J. (2014. Randomized Caches Considered Harmful in Hard Real-Time Systems. LITES, 1(1, 03:1-03:13. provides a critical analysis of the weaknesses and risks entailed in using randomized caches in hard real-time systems. In order to provide the interested reader with a fuller, balanced appreciation of the subject matter, a critical analysis of the benefits brought about by that innovation should be provided also. This short paper addresses that need by revisiting the array of issues addressed in the cited work, in the light of the latest advances to the relevant state of the art. Accordingly, we show that the potential benefits of randomized caches do offset their limitations, causing them to be - when used in conjunction with PTA - a serious competitor to conventional designs.

  9. Performance Evaluation of Moving Small-Cell Network with Proactive Cache

    Directory of Open Access Journals (Sweden)

    Young Min Kwon

    2016-01-01

    Full Text Available Due to rapid growth in mobile traffic, mobile network operators (MNOs are considering the deployment of moving small-cells (mSCs. mSC is a user-centric network which provides voice and data services during mobility. mSC can receive and forward data traffic via wireless backhaul and sidehaul links. In addition, due to the predictive nature of users demand, mSCs can proactively cache the predicted contents in off-peak-traffic periods. Due to these characteristics, MNOs consider mSCs as a cost-efficient solution to not only enhance the system capacity but also provide guaranteed quality of service (QoS requirements to moving user equipment (UE in peak-traffic periods. In this paper, we conduct extensive system level simulations to analyze the performance of mSCs with varying cache size and content popularity and their effect on wireless backhaul load. The performance evaluation confirms that the QoS of moving small-cell UE (mSUE notably improves by using mSCs together with proactive caching. We also show that the effective use of proactive cache significantly reduces the wireless backhaul load and increases the overall network capacity.

  10. TaPT: Temperature-Aware Dynamic Cache Optimization for Embedded Systems

    Directory of Open Access Journals (Sweden)

    Tosiron Adegbija

    2017-12-01

    Full Text Available Embedded systems have stringent design constraints, which has necessitated much prior research focus on optimizing energy consumption and/or performance. Since embedded systems typically have fewer cooling options, rising temperature, and thus temperature optimization, is an emergent concern. Most embedded systems only dissipate heat by passive convection, due to the absence of dedicated thermal management hardware mechanisms. The embedded system’s temperature not only affects the system’s reliability, but can also affect the performance, power, and cost. Thus, embedded systems require efficient thermal management techniques. However, thermal management can conflict with other optimization objectives, such as execution time and energy consumption. In this paper, we focus on managing the temperature using a synergy of cache optimization and dynamic frequency scaling, while also optimizing the execution time and energy consumption. This paper provides new insights on the impact of cache parameters on efficient temperature-aware cache tuning heuristics. In addition, we present temperature-aware phase-based tuning, TaPT, which determines Pareto optimal clock frequency and cache configurations for fine-grained execution time, energy, and temperature tradeoffs. TaPT enables autonomous system optimization and also allows designers to specify temperature constraints and optimization priorities. Experiments show that TaPT can effectively reduce execution time, energy, and temperature, while imposing minimal hardware overhead.

  11. Greatly improved cache update times for conditions data with Frontier/Squid

    Energy Technology Data Exchange (ETDEWEB)

    Dykstra, Dave; Lueking, Lee, E-mail: dwd@fnal.go [Computing Division, Fermilab, Batavia, IL (United States)

    2010-04-01

    The CMS detector project loads copies of conditions data to over 100,000 computer cores worldwide by using a software subsystem called Frontier. This subsystem translates database queries into HTTP, looks up the results in a central database at CERN, and caches the results in an industry-standard HTTP proxy/caching server called Squid. One of the most challenging aspects of any cache system is coherency, that is, ensuring that changes made to the underlying data get propagated out to all clients in a timely manner. Recently, the Frontier system was enhanced to drastically reduce the time for changes to be propagated everywhere without heavily loading servers. The propagation time is now as low as 15 minutes for some kinds of data and no more than 60 minutes for the rest of the data. This was accomplished by taking advantage of an HTTP and Squid feature called If-Modified-Since. In order to use this feature, the Frontier server sends a Last-Modified timestamp, but since modification times are not normally tracked by Oracle databases, a PL/SQL program was developed to track the modification times of database tables. We discuss the details of this caching scheme and the obstacles overcome including database and Squid bugs.

  12. Greatly improved cache update times for conditions data with Frontier/Squid

    International Nuclear Information System (INIS)

    Dykstra, Dave; Lueking, Lee

    2009-01-01

    The CMS detector project loads copies of conditions data to over 100,000 computer cores worldwide by using a software subsystem called Frontier. This subsystem translates database queries into HTTP, looks up the results in a central database at CERN, and caches the results in an industry-standard HTTP proxy/caching server called Squid. One of the most challenging aspects of any cache system is coherency, that is, ensuring that changes made to the underlying data get propagated out to all clients in a timely manner. Recently, the Frontier system was enhanced to drastically reduce the time for changes to be propagated everywhere without heavily loading servers. The propagation time is now as low as 15 minutes for some kinds of data and no more than 60 minutes for the rest of the data. This was accomplished by taking advantage of an HTTP and Squid feature called If-Modified-Since. In order to use this feature, the Frontier server sends a Last-Modified timestamp, but since modification times are not normally tracked by Oracle databases, a PL/SQL program was developed to track the modification times of database tables. We discuss the details of this caching scheme and the obstacles overcome including database and Squid bugs.

  13. Delivery Time Minimization in Edge Caching: Synergistic Benefits of Subspace Alignment and Zero Forcing

    KAUST Repository

    Kakar, Jaber

    2017-10-29

    An emerging trend of next generation communication systems is to provide network edges with additional capabilities such as additional storage resources in the form of caches to reduce file delivery latency. To investigate this aspect, we study the fundamental limits of a cache-aided wireless network consisting of one central base station, $M$ transceivers and $K$ receivers from a latency-centric perspective. We use the normalized delivery time (NDT) to capture the per-bit latency for the worst-case file request pattern at high signal-to-noise ratios (SNR), normalized with respect to a reference interference-free system with unlimited transceiver cache capabilities. For various special cases with $M=\\\\{1,2\\\\}$ and $K=\\\\{1,2,3\\\\}$ that satisfy $M+K\\\\leq 4$, we establish the optimal tradeoff between cache storage and latency. This is facilitated through establishing a novel converse (for arbitrary $M$ and $K$) and an achievability scheme on the NDT. Our achievability scheme is a synergistic combination of multicasting, zero-forcing beamforming and interference alignment.

  14. Big Data Meets Telcos: A Proactive Caching Perspective

    OpenAIRE

    Bastug , Ejder; Bennis , Mehdi; Zaydan , Engin; Abdel Kader , Manhal; Karatep , Alper; Salih Er , Ahmet; Debbah , Merouane

    2015-01-01

    International audience; Mobile cellular networks are becoming increasingly complex to manage while classical deployment/optimization techniques and current solutions (i.e., cell densification, acquiring more spectrum , etc.) are cost-ineffective and thus seen as stopgaps. This calls for development of novel approaches that leverage recent advances in storage/memory, context-awareness, edge/cloud computing, and falls into framework of big data. However, the big data by itself is yet another co...

  15. Enhancement web proxy cache performance using Wrapper Feature Selection methods with NB and J48

    Science.gov (United States)

    Mahmoud Al-Qudah, Dua'a.; Funke Olanrewaju, Rashidah; Wong Azman, Amelia

    2017-11-01

    Web proxy cache technique reduces response time by storing a copy of pages between client and server sides. If requested pages are cached in the proxy, there is no need to access the server. Due to the limited size and excessive cost of cache compared to the other storages, cache replacement algorithm is used to determine evict page when the cache is full. On the other hand, the conventional algorithms for replacement such as Least Recently Use (LRU), First in First Out (FIFO), Least Frequently Use (LFU), Randomized Policy etc. may discard important pages just before use. Furthermore, using conventional algorithm cannot be well optimized since it requires some decision to intelligently evict a page before replacement. Hence, most researchers propose an integration among intelligent classifiers and replacement algorithm to improves replacement algorithms performance. This research proposes using automated wrapper feature selection methods to choose the best subset of features that are relevant and influence classifiers prediction accuracy. The result present that using wrapper feature selection methods namely: Best First (BFS), Incremental Wrapper subset selection(IWSS)embedded NB and particle swarm optimization(PSO)reduce number of features and have a good impact on reducing computation time. Using PSO enhance NB classifier accuracy by 1.1%, 0.43% and 0.22% over using NB with all features, using BFS and using IWSS embedded NB respectively. PSO rises J48 accuracy by 0.03%, 1.91 and 0.04% over using J48 classifier with all features, using IWSS-embedded NB and using BFS respectively. While using IWSS embedded NB fastest NB and J48 classifiers much more than BFS and PSO. However, it reduces computation time of NB by 0.1383 and reduce computation time of J48 by 2.998.

  16. Assessing Programming Costs of Explicit Memory Localization on a Large Scale Shared Memory Multiprocessor

    Directory of Open Access Journals (Sweden)

    Silvio Picano

    1992-01-01

    Full Text Available We present detailed experimental work involving a commercially available large scale shared memory multiple instruction stream-multiple data stream (MIMD parallel computer having a software controlled cache coherence mechanism. To make effective use of such an architecture, the programmer is responsible for designing the program's structure to match the underlying multiprocessors capabilities. We describe the techniques used to exploit our multiprocessor (the BBN TC2000 on a network simulation program, showing the resulting performance gains and the associated programming costs. We show that an efficient implementation relies heavily on the user's ability to explicitly manage the memory system.

  17. An IPv6 routing lookup algorithm using weight-balanced tree based on prefix value for virtual router

    Science.gov (United States)

    Chen, Lingjiang; Zhou, Shuguang; Zhang, Qiaoduo; Li, Fenghua

    2016-10-01

    Virtual router enables the coexistence of different networks on the same physical facility and has lately attracted a great deal of attention from researchers. As the number of IPv6 addresses is rapidly increasing in virtual routers, designing an efficient IPv6 routing lookup algorithm is of great importance. In this paper, we present an IPv6 lookup algorithm called weight-balanced tree (WBT). WBT merges Forwarding Information Bases (FIBs) of virtual routers into one spanning tree, and compresses the space cost. WBT's average time complexity and the worst case time complexity of lookup and update process are both O(logN) and space complexity is O(cN) where N is the size of routing table and c is a constant. Experiments show that WBT helps reduce more than 80% Static Random Access Memory (SRAM) cost in comparison to those separation schemes. WBT also achieves the least average search depth comparing with other homogeneous algorithms.

  18. Servidor proxy caché: comprensión y asimilación tecnológica

    Directory of Open Access Journals (Sweden)

    Carlos E. Gómez

    2012-01-01

    Full Text Available Los proveedores de acceso a Internet usualmente incluyen el concepto de aceleradores de Internet para reducir el tiempo promedio que tarda un navegador en obtener los archivos solicitados. Para los administradores del sistema es difícil elegir la configuración del servidor proxy caché, ya que es necesario decidir los valores que se deben usar en diferentes variables. En este artículo se presenta la forma como se abordó el proceso de comprensión y asimilación tecnológica del servicio de proxy caché, un servicio de alto impacto organizacional. Además, este artículo es producto del proyecto de investigación “Análisis de configuraciones de servidores proxy caché”, en el cual se estudiaron aspectos relevantes del rendimiento de Squid como servidor proxy caché.

  19. High-speed mapping of water isotopes and residence time in Cache Slough Complex, San Francisco Bay Delta, CA

    Data.gov (United States)

    Department of the Interior — Real-time, high frequency (1-second sample interval) GPS location, water quality, and water isotope (δ2H, δ18O) data was collected in the Cache Slough Complex (CSC),...

  20. Wolves, Canis lupus, carry and cache the collars of radio-collared White-tailed Deer, Odocoileus virginianus, they killed

    Science.gov (United States)

    Nelson, Michael E.; Mech, L. David

    2011-01-01

    Wolves (Canis lupus) in northeastern Minnesota cached six radio-collars (four in winter, two in spring-summer) of 202 radio-collared White-tailed Deer (Odocoileus virginianus) they killed or consumed from 1975 to 2010. A Wolf bedded on top of one collar cached in snow. We found one collar each at a Wolf den and Wolf rendezvous site, 2.5 km and 0.5 km respectively, from each deer's previous locations.

  1. The development of caching and object permanence in Western scrub-jays (Aphelocoma californica): which emerges first?

    Science.gov (United States)

    Salwiczek, Lucie H; Emery, Nathan J; Schlinger, Barney; Clayton, Nicola S

    2009-08-01

    Recent studies on the food-caching behavior of corvids have revealed complex physical and social skills, yet little is known about the ontogeny of food caching in relation to the development of cognitive capacities. Piagetian object permanence is the understanding that objects continue to exist even when they are no longer visible. Here, the authors focus on Piagetian Stages 3 and 4, because they are hallmarks in the cognitive development of both young children and animals. Our aim is to determine in a food-caching corvid, the Western scrub-jay, whether (1) Piagetian Stage 4 competence and tentative caching (i.e., hiding an item invisibly and retrieving it without delay), emerge concomitantly or consecutively; (2) whether experiencing the reappearance of hidden objects enhances the timing of the appearance of object permanence; and (3) discuss how the development of object permanence is related to behavioral development and sensorimotor intelligence. Our findings suggest that object permanence Stage 4 emerges before tentative caching, and independent of environmental influences, but that once the birds have developed simple object-permanence, then social learning might advance the interval after which tentative caching commences. Copyright 2009 APA, all rights reserved.

  2. A New Caching Technique to Support Conjunctive Queries in P2P DHT

    Science.gov (United States)

    Kobatake, Koji; Tagashira, Shigeaki; Fujita, Satoshi

    P2P DHT (Peer-to-Peer Distributed Hash Table) is one of typical techniques for realizing an efficient management of shared resources distributed over a network and a keyword search over such networks in a fully distributed manner. In this paper, we propose a new method for supporting conjunctive queries in P2P DHT. The basic idea of the proposed technique is to share a global information on past trials by conducting a local caching of search results for conjunctive queries and by registering the fact to the global DHT. Such a result caching is expected to significantly reduce the amount of transmitted data compared with conventional schemes. The effect of the proposed method is experimentally evaluated by simulation. The result of experiments indicates that by using the proposed method, the amount of returned data is reduced by 60% compared with conventional P2P DHT which does not support conjunctive queries.

  3. XRootd, disk-based, caching proxy for optimization of data access, data placement and data replication

    International Nuclear Information System (INIS)

    Bauerdick, L A T; Bloom, K; Bockelman, B; Bradley, D C; Dasu, S; Dost, J M; Sfiligoi, I; Tadel, A; Tadel, M; Wuerthwein, F; Yagil, A

    2014-01-01

    Following the success of the XRootd-based US CMS data federation, the AAA project investigated extensions of the federation architecture by developing two sample implementations of an XRootd, disk-based, caching proxy. The first one simply starts fetching a whole file as soon as a file open request is received and is suitable when completely random file access is expected or it is already known that a whole file be read. The second implementation supports on-demand downloading of partial files. Extensions to the Hadoop Distributed File System have been developed to allow for an immediate fallback to network access when local HDFS storage fails to provide the requested block. Both cache implementations are in pre-production testing at UCSD.

  4. The Use of Proxy Caches for File Access in a Multi-Tier Grid Environment

    International Nuclear Information System (INIS)

    Brun, R; Duellmann, D; Ganis, G; Janyst, L; Peters, A J; Rademakers, F; Sindrilaru, E; Hanushevsky, A

    2011-01-01

    The use of proxy caches has been extensively studied in the HEP environment for efficient access of database data and showed significant performance with only very moderate operational effort at higher grid tiers (T2, T3). In this contribution we propose to apply the same concept to the area of file access and analyse the possible performance gains, operational impact on site services and applicability to different HEP use cases. Base on a proof-of-concept studies with a modified XROOT proxy server we review the cache efficiency and overheads for access patterns of typical ROOT based analysis programs. We conclude with a discussion of the potential role of this new component at the different tiers of a distributed computing grid.

  5. Federated or cached searches: providing expected performance from multiple invasive species databases

    Science.gov (United States)

    Graham, Jim; Jarnevich, Catherine S.; Simpson, Annie; Newman, Gregory J.; Stohlgren, Thomas J.

    2011-01-01

    Invasive species are a universal global problem, but the information to identify them, manage them, and prevent invasions is stored around the globe in a variety of formats. The Global Invasive Species Information Network is a consortium of organizations working toward providing seamless access to these disparate databases via the Internet. A distributed network of databases can be created using the Internet and a standard web service protocol. There are two options to provide this integration. First, federated searches are being proposed to allow users to search “deep” web documents such as databases for invasive species. A second method is to create a cache of data from the databases for searching. We compare these two methods, and show that federated searches will not provide the performance and flexibility required from users and a central cache of the datum are required to improve performance.

  6. Feasibility Report and Environmental Statement for Water Resources Development, Cache Creek Basin, California

    Science.gov (United States)

    1979-02-01

    classified as Porno , Lake Miwok, and Patwin. Recent surveys within the Clear Lake-Cache Creek Basin have located 28 archeological sites, some of which...additional 8,400 acre-feet annually to the Lakeport area. Porno Reservoir on Kelsey Creek, being studied by Lake County, also would supplement M&l water...project on Scotts Creek could provide 9,100 acre- feet annually of irrigation water. Also, as previously discussed, Porno Reservoir would furnish

  7. Fox squirrels match food assessment and cache effort to value and scarcity.

    Directory of Open Access Journals (Sweden)

    Mikel M Delgado

    Full Text Available Scatter hoarders must allocate time to assess items for caching, and to carry and bury each cache. Such decisions should be driven by economic variables, such as the value of the individual food items, the scarcity of these items, competition for food items and risk of pilferage by conspecifics. The fox squirrel, an obligate scatter-hoarder, assesses cacheable food items using two overt movements, head flicks and paw manipulations. These behaviors allow an examination of squirrel decision processes when storing food for winter survival. We measured wild squirrels' time allocations and frequencies of assessment and investment behaviors during periods of food scarcity (summer and abundance (fall, giving the squirrels a series of 15 items (alternating five hazelnuts and five peanuts. Assessment and investment per cache increased when resource value was higher (hazelnuts or resources were scarcer (summer, but decreased as scarcity declined (end of sessions. This is the first study to show that assessment behaviors change in response to factors that indicate daily and seasonal resource abundance, and that these factors may interact in complex ways to affect food storing decisions. Food-storing tree squirrels may be a useful and important model species to understand the complex economic decisions made under natural conditions.

  8. Secure File Allocation and Caching in Large-scale Distributed Systems

    DEFF Research Database (Denmark)

    Di Mauro, Alessio; Mei, Alessandro; Jajodia, Sushil

    2012-01-01

    In this paper, we present a file allocation and caching scheme that guarantees high assurance, availability, and load balancing in a large-scale distributed file system that can support dynamic updates of authorization policies. The scheme uses fragmentation and replication to store files with hi......-balancing, and reducing delay of read operations. The system offers a trade-off-between performance and security that is dynamically tunable according to the current level of threat. We validate our mechanisms with extensive simulations in an Internet-like network.......In this paper, we present a file allocation and caching scheme that guarantees high assurance, availability, and load balancing in a large-scale distributed file system that can support dynamic updates of authorization policies. The scheme uses fragmentation and replication to store files with high...... security requirements in a system composed of a majority of low-security servers. We develop mechanisms to fragment files, to allocate them into multiple servers, and to cache them as close as possible to their readers while preserving the security requirement of the files, providing load...

  9. Shared Memory Parallelization of an Implicit ADI-type CFD Code

    Science.gov (United States)

    Hauser, Th.; Huang, P. G.

    1999-01-01

    A parallelization study designed for ADI-type algorithms is presented using the OpenMP specification for shared-memory multiprocessor programming. Details of optimizations specifically addressed to cache-based computer architectures are described and performance measurements for the single and multiprocessor implementation are summarized. The paper demonstrates that optimization of memory access on a cache-based computer architecture controls the performance of the computational algorithm. A hybrid MPI/OpenMP approach is proposed for clusters of shared memory machines to further enhance the parallel performance. The method is applied to develop a new LES/DNS code, named LESTool. A preliminary DNS calculation of a fully developed channel flow at a Reynolds number of 180, Re(sub tau) = 180, has shown good agreement with existing data.

  10. Evaluating Multicore Algorithms on the Unified Memory Model

    Directory of Open Access Journals (Sweden)

    John E. Savage

    2009-01-01

    Full Text Available One of the challenges to achieving good performance on multicore architectures is the effective utilization of the underlying memory hierarchy. While this is an issue for single-core architectures, it is a critical problem for multicore chips. In this paper, we formulate the unified multicore model (UMM to help understand the fundamental limits on cache performance on these architectures. The UMM seamlessly handles different types of multiple-core processors with varying degrees of cache sharing at different levels. We demonstrate that our model can be used to study a variety of multicore architectures on a variety of applications. In particular, we use it to analyze an option pricing problem using the trinomial model and develop an algorithm for it that has near-optimal memory traffic between cache levels. We have implemented the algorithm on a two Quad-Core Intel Xeon 5310 1.6 GHz processors (8 cores. It achieves a peak performance of 19.5 GFLOPs, which is 38% of the theoretical peak of the multicore system. We demonstrate that our algorithm outperforms compiler-optimized and auto-parallelized code by a factor of up to 7.5.

  11. dCache: implementing a high-end NFSv4.1 service using a Java NIO framework

    CERN Multimedia

    CERN. Geneva

    2012-01-01

    dCache is a high performance scalable storage system widely used by HEP community. In addition to set of home grown protocols we also provide industry standard access mechanisms like WebDAV and NFSv4.1. This support places dCache as a direct competitor to commercial solutions. Nevertheless conforming to a protocol is not enough; our implementations must perform comparably or even better than commercial systems. To achieve this, dCache uses two high-end IO frameworks from well know application servers: GlassFish and JBoss. This presentation describes how we implemented an rfc1831 and rfc2203 compliant ONC RPC (Sun RPC) service based on the Grizzly NIO framework, part of the GlassFish application server. This ONC RPC service is the key component of dCache’s NFSv4.1 implementation, but is independent of dCache and available for other projects. We will also show some details of dCache NFS v4.1 implementations, describe some of the Java NIO techniques used and, finally, present details of our performance e...

  12. Temperature and Discharge on a Highly Altered Stream in Utah's Cache Valley

    OpenAIRE

    Pappas, Andy

    2013-01-01

    To study the River Continuum Concept (RCC) and the Serial Discontinuity Hypothesis (SDH), I looked at temperature and discharge changes along 52 km of the Little Bear River in Cache Valley, Utah. The Little Bear River is a fourth order stream with one major reservoir, a number of irrigation diversions, and one major tributary, the East Fork of the Little Bear River. Discharge data was collected at six sites on 29 September 2012 and temperature data was collected hourly at eleven sites from 1 ...

  13. Comparison of the Frontier Distributed Database Caching System with NoSQL Databases

    CERN Multimedia

    CERN. Geneva

    2012-01-01

    Non-relational "NoSQL" databases such as Cassandra and CouchDB are best known for their ability to scale to large numbers of clients spread over a wide area. The Frontier distributed database caching system, used in production by the Large Hadron Collider CMS and ATLAS detector projects, is based on traditional SQL databases but also has the same high scalability and wide-area distributability for an important subset of applications. This paper compares the architectures, behavior, performance, and maintainability of the two different approaches and identifies the criteria for choosing which approach to prefer over the other.

  14. On the Performance of Three In-Memory Data Systems for On Line Analytical Processing

    Directory of Open Access Journals (Sweden)

    Ionut HRUBARU

    2017-01-01

    Full Text Available In-memory database systems are among the most recent and most promising Big Data technologies, being developed and released either as brand new distributed systems or as extensions of old monolith (centralized database systems. As name suggests, in-memory systems cache all the data into special memory structures. Many are part of the NewSQL strand and target to bridge the gap between OLTP and OLAP into so-called Hybrid Transactional Analytical Systems (HTAP. This paper aims to test the performance of using such type of systems for TPCH analytical workloads. Performance is analyzed in terms of data loading, memory footprint and execution time of the TPCH query set for three in-memory data systems: Oracle, SQL Server and MemSQL. Tests are subsequently deployed on classical on-disk architectures and results compared to in-memory solutions. As in-memory is an enterprise edition feature, associated costs are also considered.

  15. Flood Frequency Analysis of Future Climate Projections in the Cache Creek Watershed

    Science.gov (United States)

    Fischer, I.; Trihn, T.; Ishida, K.; Jang, S.; Kavvas, E.; Kavvas, M. L.

    2014-12-01

    Effects of climate change on hydrologic flow regimes, particularly extreme events, necessitate modeling of future flows to best inform water resources management. Future flow projections may be modeled through the joint use of carbon emission scenarios, general circulation models and watershed models. This research effort ran 13 simulations for carbon emission scenarios (taken from the A1, A2 and B1 families) over the 21st century (2001-2100) for the Cache Creek watershed in Northern California. Atmospheric data from general circulation models, CCSM3 and ECHAM5, were dynamically downscaled to a 9 km resolution using MM5, a regional mesoscale model, before being input into the physically based watershed environmental hydrology (WEHY) model. Ensemble mean and standard deviation of simulated flows describe the expected hydrologic system response. Frequency histograms and cumulative distribution functions characterize the range of hydrologic responses that may occur. The modeled flow results comprise a dataset suitable for time series and frequency analysis allowing for more robust system characterization, including indices such as the 100 year flood return period. These results are significant for water quality management as the Cache Creek watershed is severely impacted by mercury pollution from historic mining activities. Extreme flow events control mercury fate and transport affecting the downstream water bodies of the Sacramento River and Sacramento- San Joaquin Delta which provide drinking water to over 25 million people.

  16. Replicas Strategy and Cache Optimization of Video Surveillance Systems Based on Cloud Storage

    Directory of Open Access Journals (Sweden)

    Rongheng Li

    2018-04-01

    Full Text Available With the rapid development of video surveillance technology, especially the popularity of cloud-based video surveillance applications, video data begins to grow explosively. However, in the cloud-based video surveillance system, replicas occupy an amount of storage space. Also, the slow response to video playback constrains the performance of the system. In this paper, considering the characteristics of video data comprehensively, we propose a dynamic redundant replicas mechanism based on security levels that can dynamically adjust the number of replicas. Based on the location correlation between cameras, this paper also proposes a data cache strategy to improve the response speed of data reading. Experiments illustrate that: (1 our dynamic redundant replicas mechanism can save storage space while ensuring data security; (2 the cache mechanism can predict the playback behaviors of the users in advance and improve the response speed of data reading according to the location and time correlation of the front-end cameras; and (3 in terms of cloud-based video surveillance, our proposed approaches significantly outperform existing methods.

  17. Agricultural Influences on Cache Valley, Utah Air Quality During a Wintertime Inversion Episode

    Science.gov (United States)

    Silva, P. J.

    2017-12-01

    Several of northern Utah's intermountain valleys are classified as non-attainment for fine particulate matter. Past data indicate that ammonium nitrate is the major contributor to fine particles and that the gas phase ammonia concentrations are among the highest in the United States. During the 2017 Utah Winter Fine Particulate Study, USDA brought a suite of online and real-time measurement methods to sample particulate matter and potential gaseous precursors from agricultural emissions in the Cache Valley. Instruments were co-located at the State of Utah monitoring site in Smithfield, Utah from January 21st through February 12th, 2017. A Scanning mobility particle sizer (SMPS) and aerodynamic particle sizer (APS) acquired size distributions of particles from 10 nm - 10 μm in 5-min intervals. A URG ambient ion monitor (AIM) gave hourly concentrations for gas and particulate ions and a Chromatotec Trsmedor gas chromatograph obtained 10 minute measurements of gaseous sulfur species. High ammonia concentrations were detected at the Smithfield site with concentrations above 100 ppb at times, indicating a significant influence from agriculture at the sampling site. Ammonia is not the only agricultural emission elevated in Cache Valley during winter, as reduced sulfur gas concentrations of up to 20 ppb were also detected. Dimethylsulfide was the major sulfur-containing gaseous species. Analysis indicates that particle growth and particle nucleation events were both observed by the SMPS. Relationships between gas and particulate concentrations and correlations between the two will be discussed.

  18. Observations of territorial breeding common ravens caching eggs of greater sage-grouse

    Science.gov (United States)

    Howe, Kristy B.; Coates, Peter S.

    2015-01-01

    Previous investigations using continuous video monitoring of greater sage-grouse Centrocercus urophasianus nests have unambiguously identified common ravens Corvus corax as an important egg predator within the western United States. The quantity of greater sage-grouse eggs an individual common raven consumes during the nesting period and the extent to which common ravens actively hunt greater sage-grouse nests are largely unknown. However, some evidence suggests that territorial breeding common ravens, rather than nonbreeding transients, are most likely responsible for nest depredations. We describe greater sage-grouse egg depredation observations obtained opportunistically from three common raven nests located in Idaho and Nevada where depredated greater sage-grouse eggs were found at or in the immediate vicinity of the nest site, including the caching of eggs in nearby rock crevices. We opportunistically monitored these nests by counting and removing depredated eggs and shell fragments from the nest sites during each visit to determine the extent to which the common raven pairs preyed on greater sage-grouse eggs. To our knowledge, our observations represent the first evidence that breeding, territorial pairs of common ravens cache greater sage-grouse eggs and are capable of depredating multiple greater sage-grouse nests.

  19. Reducing the stochasticity of crystal nucleation to enable subnanosecond memory writing

    Science.gov (United States)

    Rao, Feng; Ding, Keyuan; Zhou, Yuxing; Zheng, Yonghui; Xia, Mengjiao; Lv, Shilong; Song, Zhitang; Feng, Songlin; Ronneberger, Ider; Mazzarello, Riccardo; Zhang, Wei; Ma, Evan

    2017-12-01

    Operation speed is a key challenge in phase-change random-access memory (PCRAM) technology, especially for achieving subnanosecond high-speed cache memory. Commercialized PCRAM products are limited by the tens of nanoseconds writing speed, originating from the stochastic crystal nucleation during the crystallization of amorphous germanium antimony telluride (Ge2Sb2Te5). Here, we demonstrate an alloying strategy to speed up the crystallization kinetics. The scandium antimony telluride (Sc0.2Sb2Te3) compound that we designed allows a writing speed of only 700 picoseconds without preprogramming in a large conventional PCRAM device. This ultrafast crystallization stems from the reduced stochasticity of nucleation through geometrically matched and robust scandium telluride (ScTe) chemical bonds that stabilize crystal precursors in the amorphous state. Controlling nucleation through alloy design paves the way for the development of cache-type PCRAM technology to boost the working efficiency of computing systems.

  20. Directions for memory hierarchies and their components: research and development

    International Nuclear Information System (INIS)

    Smith, A.J.

    1978-10-01

    The memory hierarchy is usually the largest identifiable part of a computer system and making effective use of it is critical to the operation and use of the system. The levels of such a memory hierarchy are considered and the state of the art and likely directions for both research and development are described. Algorithmic and logical features of the hierarchy not directly associated with specific components are also discussed. Among the problems believed to be the most significant are the following: (a) evaluate the effectiveness of gap filler technology as a level of storage between main memory and disk, and if it proves to be effective, determine how/where it should be used, (b) develop algorithms for the use of mass storage in a large computer system, and (c) determine how cache memories should be implemented in very large, fast multiprocessor systems

  1. Collective Memory Transfers for Multi-Core Chips

    Energy Technology Data Exchange (ETDEWEB)

    Michelogiannakis, George; Williams, Alexander; Shalf, John

    2013-11-13

    Future performance improvements for microprocessors have shifted from clock frequency scaling towards increases in on-chip parallelism. Performance improvements for a wide variety of parallel applications require domain-decomposition of data arrays from a contiguous arrangement in memory to a tiled layout for on-chip L1 data caches and scratchpads. How- ever, DRAM performance suffers under the non-streaming access patterns generated by many independent cores. We propose collective memory scheduling (CMS) that actively takes control of collective memory transfers such that requests arrive in a sequential and predictable fashion to the memory controller. CMS uses the hierarchically tiled arrays formal- ism to compactly express collective operations, which greatly improves programmability over conventional prefetch or list- DMA approaches. CMS reduces application execution time by up to 32% and DRAM read power by 2.2×, compared to a baseline DMA architecture such as STI Cell.

  2. Memory architecture

    NARCIS (Netherlands)

    2012-01-01

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

  3. Tannin concentration enhances seed caching by scatter-hoarding rodents: An experiment using artificial ‘seeds’

    Science.gov (United States)

    Wang, Bo; Chen, Jin

    2008-11-01

    Tannins are very common among plant seeds but their effects on the fate of seeds, for example, via mediation of the feeding preferences of scatter-hoarding rodents, are poorly understood. In this study, we created a series of artificial 'seeds' that only differed in tannin concentration and the type of tannin, and placed them in a pine forest in the Shangri-La Alpine Botanical Garden, Yunnan Province of China. Two rodent species ( Apodemus latronum and A. chevrieri) showed significant preferences for 'seeds' with different tannin concentrations. A significantly higher proportion of seeds with low tannin concentration were consumed in situ compared with seeds with a higher tannin concentration. Meanwhile, the tannin concentration was significantly positively correlated with the proportion of seeds cached. The different types of tannin (hydrolysable tannin vs condensed tannin) did not differ significantly in their effect on the proportion of seeds eaten in situ vs seeds cached. Tannin concentrations had no significant effect on the distance that cached seeds were carried, which suggests that rodents may respond to different seed traits in deciding whether or not to cache seeds and how far they will transport seeds.

  4. Application of computer graphics to generate coal resources of the Cache coal bed, Recluse geologic model area, Campbell County, Wyoming

    Science.gov (United States)

    Schneider, G.B.; Crowley, S.S.; Carey, M.A.

    1982-01-01

    Low-sulfur subbituminous coal resources have been calculated, using both manual and computer methods, for the Cache coal bed in the Recluse Model Area, which covers the White Tail Butte, Pitch Draw, Recluse, and Homestead Draw SW 7 1/2 minute quadrangles, Campbell County, Wyoming. Approximately 275 coal thickness measurements obtained from drill hole data are evenly distributed throughout the area. The Cache coal and associated beds are in the Paleocene Tongue River Member of the Fort Union Formation. The depth from the surface to the Cache bed ranges from 269 to 1,257 feet. The thickness of the coal is as much as 31 feet, but in places the Cache coal bed is absent. Comparisons between hand-drawn and computer-generated isopach maps show minimal differences. Total coal resources calculated by computer show the bed to contain 2,316 million short tons or about 6.7 percent more than the hand-calculated figure of 2,160 million short tons.

  5. Achieving cost/performance balance ratio using tiered storage caching techniques: A case study with CephFS

    Science.gov (United States)

    Poat, M. D.; Lauret, J.

    2017-10-01

    As demand for widely accessible storage capacity increases and usage is on the rise, steady IO performance is desired but tends to suffer within multi-user environments. Typical deployments use standard hard drives as the cost per/GB is quite low. On the other hand, HDD based solutions for storage is not known to scale well with process concurrency and soon enough, high rate of IOPs create a “random access” pattern killing performance. Though not all SSDs are alike, SSDs are an established technology often used to address this exact “random access” problem. In this contribution, we will first discuss the IO performance of many different SSD drives (tested in a comparable and standalone manner). We will then be discussing the performance and integrity of at least three low-level disk caching techniques (Flashcache, dm-cache, and bcache) including individual policies, procedures, and IO performance. Furthermore, the STAR online computing infrastructure currently hosts a POSIX-compliant Ceph distributed storage cluster - while caching is not a native feature of CephFS (only exists in the Ceph Object store), we will show how one can implement a caching mechanism profiting from an implementation at a lower level. As our illustration, we will present our CephFS setup, IO performance tests, and overall experience from such configuration. We hope this work will service the community’s interest for using disk-caching mechanisms with applicable uses such as distributed storage systems and seeking an overall IO performance gain.

  6. An ecological response model for the Cache la Poudre River through Fort Collins

    Science.gov (United States)

    Shanahan, Jennifer; Baker, Daniel; Bledsoe, Brian P.; Poff, LeRoy; Merritt, David M.; Bestgen, Kevin R.; Auble, Gregor T.; Kondratieff, Boris C.; Stokes, John; Lorie, Mark; Sanderson, John

    2014-01-01

    The Poudre River Ecological Response Model (ERM) is a collaborative effort initiated by the City of Fort Collins and a team of nine river scientists to provide the City with a tool to improve its understanding of the past, present, and likely future conditions of the Cache la Poudre River ecosystem. The overall ecosystem condition is described through the measurement of key ecological indicators such as shape and character of the stream channel and banks, streamside plant communities and floodplain wetlands, aquatic vegetation and insects, and fishes, both coolwater trout and warmwater native species. The 13- mile-long study area of the Poudre River flows through Fort Collins, Colorado, and is located in an ecological transition zone between the upstream, cold-water, steep-gradient system in the Front Range of the Southern Rocky Mountains and the downstream, warm-water, low-gradient reach in the Colorado high plains.

  7. Comparison of the Frontier Distributed Database Caching System to NoSQL Databases

    Science.gov (United States)

    Dykstra, Dave

    2012-12-01

    One of the main attractions of non-relational “NoSQL” databases is their ability to scale to large numbers of readers, including readers spread over a wide area. The Frontier distributed database caching system, used in production by the Large Hadron Collider CMS and ATLAS detector projects for Conditions data, is based on traditional SQL databases but also adds high scalability and the ability to be distributed over a wide-area for an important subset of applications. This paper compares the major characteristics of the two different approaches and identifies the criteria for choosing which approach to prefer over the other. It also compares in some detail the NoSQL databases used by CMS and ATLAS: MongoDB, CouchDB, HBase, and Cassandra.

  8. Comparison of the Frontier Distributed Database Caching System to NoSQL Databases

    International Nuclear Information System (INIS)

    Dykstra, Dave

    2012-01-01

    One of the main attractions of non-relational “NoSQL” databases is their ability to scale to large numbers of readers, including readers spread over a wide area. The Frontier distributed database caching system, used in production by the Large Hadron Collider CMS and ATLAS detector projects for Conditions data, is based on traditional SQL databases but also adds high scalability and the ability to be distributed over a wide-area for an important subset of applications. This paper compares the major characteristics of the two different approaches and identifies the criteria for choosing which approach to prefer over the other. It also compares in some detail the NoSQL databases used by CMS and ATLAS: MongoDB, CouchDB, HBase, and Cassandra.

  9. A Cache-Oblivious Implicit Dictionary with the Working Set Property

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Kejlberg-Rasmussen, Casper; Truelsen, Jakob

    2010-01-01

    In this paper we present an implicit dictionary with the working set property i.e. a dictionary supporting \\op{insert}($e$), \\op{delete}($x$) and \\op{predecessor}($x$) in~$\\O(\\log n)$ time and \\op{search}($x$) in $\\O(\\log\\ell)$ time, where $n$ is the number of elements stored in the dictionary...... and $\\ell$ is the number of distinct elements searched for since the element with key~$x$ was last searched for. The dictionary stores the elements in an array of size~$n$ using \\emph{no} additional space. In the cache-oblivious model the operations \\op{insert}($e$), \\op{delete}($x$) and \\op...

  10. Caching behaviour by red squirrels may contribute to food conditioning of grizzly bears

    Directory of Open Access Journals (Sweden)

    Julia Elizabeth Put

    2017-08-01

    Full Text Available We describe an interspecific relationship wherein grizzly bears (Ursus arctos horribilis appear to seek out and consume agricultural seeds concentrated in the middens of red squirrels (Tamiasciurus hudsonicus, which had collected and cached spilled grain from a railway. We studied this interaction by estimating squirrel density, midden density and contents, and bear activity along paired transects that were near (within 50 m or far (200 m from the railway. Relative to far ones, near transects had 2.4 times more squirrel sightings, but similar numbers of squirrel middens. Among 15 middens in which agricultural products were found, 14 were near the rail and 4 subsequently exhibited evidence of bear digging. Remote cameras confirmed the presence of squirrels on the rail and bears excavating middens. We speculate that obtaining grain from squirrel middens encourages bears to seek grain on the railway, potentially contributing to their rising risk of collisions with trains.

  11. I/O-Optimal Distribution Sweeping on Private-Cache Chip Multiprocessors

    DEFF Research Database (Denmark)

    Ajwani, Deepak; Sitchinava, Nodar; Zeh, Norbert

    2011-01-01

    /PB) for a number of problems on axis aligned objects; P denotes the number of cores/processors, B denotes the number of elements that fit in a cache line, N and K denote the sizes of the input and output, respectively, and sortp(N) denotes the I/O complexity of sorting N items using P processors in the PEM model...... framework was introduced recently, and a number of algorithms for problems on axis-aligned objects were obtained using this framework. The obtained algorithms were efficient but not optimal. In this paper, we improve the framework to obtain algorithms with the optimal I/O complexity of O(sortp(N) + K...

  12. Summary and Synthesis of Mercury Studies in the Cache Creek Watershed, California, 2000-01

    Science.gov (United States)

    Domagalski, Joseph L.; Slotton, Darell G.; Alpers, Charles N.; Suchanek, Thomas H.; Churchill, Ronald; Bloom, Nicolas; Ayers, Shaun M.; Clinkenbeard, John

    2004-01-01

    This report summarizes the principal findings of the Cache Creek, California, components of a project funded by the CALFED Bay?Delta Program entitled 'An Assessment of Ecological and Human Health Impacts of Mercury in the Bay?Delta Watershed.' A companion report summarizes the key findings of other components of the project based in the San Francisco Bay and the Delta of the Sacramento and San Joaquin Rivers. These summary documents present the more important findings of the various studies in a format intended for a wide audience. For more in-depth, scientific presentation and discussion of the research, a series of detailed technical reports of the integrated mercury studies is available at the following website: .

  13. Security in the Cache and Forward Architecture for the Next Generation Internet

    Science.gov (United States)

    Hadjichristofi, G. C.; Hadjicostis, C. N.; Raychaudhuri, D.

    The future Internet architecture will be comprised predominately of wireless devices. It is evident at this stage that the TCP/IP protocol that was developed decades ago will not properly support the required network functionalities since contemporary communication profiles tend to be data-driven rather than host-based. To address this paradigm shift in data propagation, a next generation architecture has been proposed, the Cache and Forward (CNF) architecture. This research investigates security aspects of this new Internet architecture. More specifically, we discuss content privacy, secure routing, key management and trust management. We identify security weaknesses of this architecture that need to be addressed and we derive security requirements that should guide future research directions. Aspects of the research can be adopted as a step-stone as we build the future Internet.

  14. Comparison of the Frontier Distributed Database Caching System with NoSQL Databases

    CERN Document Server

    Dykstra, David

    2012-01-01

    One of the main attractions of non-relational "NoSQL" databases is their ability to scale to large numbers of readers, including readers spread over a wide area. The Frontier distributed database caching system, used in production by the Large Hadron Collider CMS and ATLAS detector projects for Conditions data, is based on traditional SQL databases but also has high scalability and wide-area distributability for an important subset of applications. This paper compares the major characteristics of the two different approaches and identifies the criteria for choosing which approach to prefer over the other. It also compares in some detail the NoSQL databases used by CMS and ATLAS: MongoDB, CouchDB, HBase, and Cassandra.

  15. Comparison of the Frontier Distributed Database Caching System to NoSQL Databases

    Energy Technology Data Exchange (ETDEWEB)

    Dykstra, Dave [Fermilab

    2012-07-20

    One of the main attractions of non-relational NoSQL databases is their ability to scale to large numbers of readers, including readers spread over a wide area. The Frontier distributed database caching system, used in production by the Large Hadron Collider CMS and ATLAS detector projects for Conditions data, is based on traditional SQL databases but also adds high scalability and the ability to be distributed over a wide-area for an important subset of applications. This paper compares the major characteristics of the two different approaches and identifies the criteria for choosing which approach to prefer over the other. It also compares in some detail the NoSQL databases used by CMS and ATLAS: MongoDB, CouchDB, HBase, and Cassandra.

  16. Mercury and methylmercury concentrations and loads in the Cache Creek watershed, California

    International Nuclear Information System (INIS)

    Domagalski, Joseph L.; Alpers, Charles N.; Slotton, Darell G.; Suchanek, Thomas H.; Ayers, Shaun M.

    2004-01-01

    Concentrations and loads of total mercury and methylmercury were measured in streams draining abandoned mercury mines and in the proximity of geothermal discharge in the Cache Creek watershed of California during a 17-month period from January 2000 through May 2001. Rainfall and runoff were lower than long-term averages during the study period. The greatest loading of mercury and methylmercury from upstream sources to downstream receiving waters, such as San Francisco Bay, generally occurred during or after winter rainfall events. During the study period, loads of mercury and methylmercury from geothermal sources tended to be greater than those from abandoned mining areas, a pattern attributable to the lack of large precipitation events capable of mobilizing significant amounts of either mercury-laden sediment or dissolved mercury and methylmercury from mine waste. Streambed sediments of Cache Creek are a significant source of mercury and methylmercury to downstream receiving bodies of water. Much of the mercury in these sediments is the result of deposition over the last 100-150 years by either storm-water runoff, from abandoned mines, or continuous discharges from geothermal areas. Several geochemical constituents were useful as natural tracers for mining and geothermal areas, including the aqueous concentrations of boron, chloride, lithium and sulfate, and the stable isotopes of hydrogen and oxygen in water. Stable isotopes of water in areas draining geothermal discharges showed a distinct trend toward enrichment of 18 O compared with meteoric waters, whereas much of the runoff from abandoned mines indicated a stable isotopic pattern more consistent with local meteoric water

  17. Using dCache in Archiving Systems oriented to Earth Observation

    Science.gov (United States)

    Garcia Gil, I.; Perez Moreno, R.; Perez Navarro, O.; Platania, V.; Ozerov, D.; Leone, R.

    2012-04-01

    The object of LAST activity (Long term data Archive Study on new Technologies) is to perform an independent study on best practices and assessment of different archiving technologies mature for operation in the short and mid-term time frame, or available in the long-term with emphasis on technologies better suited to satisfy the requirements of ESA, LTDP and other European and Canadian EO partners in terms of digital information preservation and data accessibility and exploitation. During the last phase of the project, a testing of several archiving solutions has been performed in order to evaluate their suitability. In particular, dCache, aimed to provide a file system tree view of the data repository exchanging this data with backend (tertiary) Storage Systems as well as space management, pool attraction, dataset replication, hot spot determination and recovery from disk or node failures. Connected to a tertiary storage system, dCache simulates unlimited direct access storage space. Data exchanges to and from the underlying HSM are performed automatically and invisibly to the user Dcache was created to solve the requirements of big computer centers and universities with big amounts of data, putting their efforts together and founding EMI (European Middleware Initiative). At the moment being, Dcache is mature enough to be implemented, being used by several research centers of relevance (e.g. LHC storing up to 50TB/day). This solution has been not used so far in Earth Observation and the results of the study are summarized in this article, focusing on the capacities over a simulated environment to get in line with the ESA requirements for a geographically distributed storage. The challenge of a geographically distributed storage system can be summarized as the way to provide a maximum quality for storage and dissemination services with the minimum cost.

  18. Mercury and methylmercury concentrations and loads in the Cache Creek watershed, California

    Energy Technology Data Exchange (ETDEWEB)

    Domagalski, Joseph L.; Alpers, Charles N.; Slotton, Darell G.; Suchanek, Thomas H.; Ayers, Shaun M

    2004-07-05

    Concentrations and loads of total mercury and methylmercury were measured in streams draining abandoned mercury mines and in the proximity of geothermal discharge in the Cache Creek watershed of California during a 17-month period from January 2000 through May 2001. Rainfall and runoff were lower than long-term averages during the study period. The greatest loading of mercury and methylmercury from upstream sources to downstream receiving waters, such as San Francisco Bay, generally occurred during or after winter rainfall events. During the study period, loads of mercury and methylmercury from geothermal sources tended to be greater than those from abandoned mining areas, a pattern attributable to the lack of large precipitation events capable of mobilizing significant amounts of either mercury-laden sediment or dissolved mercury and methylmercury from mine waste. Streambed sediments of Cache Creek are a significant source of mercury and methylmercury to downstream receiving bodies of water. Much of the mercury in these sediments is the result of deposition over the last 100-150 years by either storm-water runoff, from abandoned mines, or continuous discharges from geothermal areas. Several geochemical constituents were useful as natural tracers for mining and geothermal areas, including the aqueous concentrations of boron, chloride, lithium and sulfate, and the stable isotopes of hydrogen and oxygen in water. Stable isotopes of water in areas draining geothermal discharges showed a distinct trend toward enrichment of {sup 18}O compared with meteoric waters, whereas much of the runoff from abandoned mines indicated a stable isotopic pattern more consistent with local meteoric water.

  19. Towards Cache-Enabled, Order-Aware, Ontology-Based Stream Reasoning Framework

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Rui; Praggastis, Brenda L.; Smith, William P.; McGuinness, Deborah L.

    2016-08-16

    While streaming data have become increasingly more popular in business and research communities, semantic models and processing software for streaming data have not kept pace. Traditional semantic solutions have not addressed transient data streams. Semantic web languages (e.g., RDF, OWL) have typically addressed static data settings and linked data approaches have predominantly addressed static or growing data repositories. Streaming data settings have some fundamental differences; in particular, data are consumed on the fly and data may expire. Stream reasoning, a combination of stream processing and semantic reasoning, has emerged with the vision of providing "smart" processing of streaming data. C-SPARQL is a prominent stream reasoning system that handles semantic (RDF) data streams. Many stream reasoning systems including C-SPARQL use a sliding window and use data arrival time to evict data. For data streams that include expiration times, a simple arrival time scheme is inadequate if the window size does not match the expiration period. In this paper, we propose a cache-enabled, order-aware, ontology-based stream reasoning framework. This framework consumes RDF streams with expiration timestamps assigned by the streaming source. Our framework utilizes both arrival and expiration timestamps in its cache eviction policies. In addition, we introduce the notion of "semantic importance" which aims to address the relevance of data to the expected reasoning, thus enabling the eviction algorithms to be more context- and reasoning-aware when choosing what data to maintain for question answering. We evaluate this framework by implementing three different prototypes and utilizing five metrics. The trade-offs of deploying the proposed framework are also discussed.

  20. Lifetime-Based Memory Management for Distributed Data Processing Systems

    DEFF Research Database (Denmark)

    Lu, Lu; Shi, Xuanhua; Zhou, Yongluan

    2016-01-01

    create a large amount of long-living data objects in the heap, which may quickly saturate the garbage collector, especially when handling a large dataset, and hence would limit the scalability of the system. To eliminate this problem, we propose a lifetime-based memory management framework, which...... the garbage collection time by up to 99.9%, 2) to achieve up to 22.7x speed up in terms of execution time in cases without data spilling and 41.6x speedup in cases with data spilling, and 3) to consume up to 46.6% less memory.......In-memory caching of intermediate data and eager combining of data in shuffle buffers have been shown to be very effective in minimizing the re-computation and I/O cost in distributed data processing systems like Spark and Flink. However, it has also been widely reported that these techniques would...

  1. MEMORY MODULATION

    Science.gov (United States)

    Roozendaal, Benno; McGaugh, James L.

    2011-01-01

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

  2. Memory Matters

    Science.gov (United States)

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

  3. Optimization and parallelization of B-spline based orbital evaluations in QMC on multi/many-core shared memory processors

    OpenAIRE

    Mathuriya, Amrita; Luo, Ye; Benali, Anouar; Shulenburger, Luke; Kim, Jeongnim

    2016-01-01

    B-spline based orbital representations are widely used in Quantum Monte Carlo (QMC) simulations of solids, historically taking as much as 50% of the total run time. Random accesses to a large four-dimensional array make it challenging to efficiently utilize caches and wide vector units of modern CPUs. We present node-level optimizations of B-spline evaluations on multi/many-core shared memory processors. To increase SIMD efficiency and bandwidth utilization, we first apply data layout transfo...

  4. The People of Bear Hunter Speak: Oral Histories of the Cache Valley Shoshones Regarding the Bear River Massacre

    OpenAIRE

    Crawford, Aaron L.

    2007-01-01

    The Cache Valley Shoshone are the survivors of the Bear River Massacre, where a battle between a group of US. volunteer troops from California and a Shoshone village degenerated into the worst Indian massacre in US. history, resulting in the deaths of over 200 Shoshones. The massacre occurred due to increasing tensions over land use between the Shoshones and the Mormon settlers. Following the massacre, the Shoshones attempted settling in several different locations in Box Elder County, eventu...

  5. Minimizing End-to-End Interference in I/O Stacks Spanning Shared Multi-Level Buffer Caches

    Science.gov (United States)

    Patrick, Christina M.

    2011-01-01

    This thesis presents an end-to-end interference minimizing uniquely designed high performance I/O stack that spans multi-level shared buffer cache hierarchies accessing shared I/O servers to deliver a seamless high performance I/O stack. In this thesis, I show that I can build a superior I/O stack which minimizes the inter-application interference…

  6. Caching-Aided Collaborative D2D Operation for Predictive Data Dissemination in Industrial IoT

    OpenAIRE

    Orsino, Antonino; Kovalchukov, Roman; Samuylov, Andrey; Moltchanov, Dmitri; Andreev, Sergey; Koucheryavy, Yevgeni; Valkama, Mikko

    2018-01-01

    Industrial automation deployments constitute challenging environments where moving IoT machines may produce high-definition video and other heavy sensor data during surveying and inspection operations. Transporting massive contents to the edge network infrastructure and then eventually to the remote human operator requires reliable and high-rate radio links supported by intelligent data caching and delivery mechanisms. In this work, we address the challenges of contents dissemination in chara...

  7. Sex Differences in Risk for Alzheimer's Disease Related to Neurotrophin Gene Polymorphisms: The Cache County Memory Study.

    Science.gov (United States)

    Matyi, Joshua; Tschanz, JoAnn T; Rattinger, Gail B; Sanders, Chelsea; Vernon, Elizabeth K; Corcoran, Chris; Kauwe, John S K; Buhusi, Mona

    2017-11-09

    Neurotrophins, including nerve-growth factor and brain-derived neurotrophic factor, have been implicated in Alzheimer's disease (AD). Associations between AD and neurotrophin signaling genes have been inconsistent, with few studies examining sex differences in risk. We examined four single-nucleotide polymorphisms (SNPs) involved in neurotrophin signaling (rs6265, rs56164415, rs2289656, rs2072446) and risk for AD by sex in a population-based sample of older adults. Three thousand four hundred and ninety-nine individuals without dementia at baseline [mean (standard deviation) age = 74.64 (6.84), 58% female] underwent dementia screening and assessment over four triennial waves. Cox regression was used to examine time to AD or right censoring for each SNP. Female carriers of the minor T allele for rs2072446 and rs56164415 had a 60% (hazard ratio [HR] = 1.60, 95% confidence interval [CI] = 1.02-2.51) and 93% (HR = 1.93, 95% CI = 1.30-2.84) higher hazard for AD, respectively, than male noncarriers of the T allele. Furthermore, male carriers of the T allele of rs2072446 had a 61% lower hazard (HR = 0.39, 95% CI = 0.14-1.06) than male noncarriers at trend-level significance (p = .07). The association between certain neurotrophin gene polymorphisms and AD differs by sex and may explain inconsistent findings in the literature. © The Author 2017. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  8. Smart Collaborative Caching for Information-Centric IoT in Fog Computing.

    Science.gov (United States)

    Song, Fei; Ai, Zheng-Yang; Li, Jun-Jie; Pau, Giovanni; Collotta, Mario; You, Ilsun; Zhang, Hong-Ke

    2017-11-01

    The significant changes enabled by the fog computing had demonstrated that Internet of Things (IoT) urgently needs more evolutional reforms. Limited by the inflexible design philosophy; the traditional structure of a network is hard to meet the latest demands. However, Information-Centric Networking (ICN) is a promising option to bridge and cover these enormous gaps. In this paper, a Smart Collaborative Caching (SCC) scheme is established by leveraging high-level ICN principles for IoT within fog computing paradigm. The proposed solution is supposed to be utilized in resource pooling, content storing, node locating and other related situations. By investigating the available characteristics of ICN, some challenges of such combination are reviewed in depth. The details of building SCC, including basic model and advanced algorithms, are presented based on theoretical analysis and simplified examples. The validation focuses on two typical scenarios: simple status inquiry and complex content sharing. The number of clusters, packet loss probability and other parameters are also considered. The analytical results demonstrate that the performance of our scheme, regarding total packet number and average transmission latency, can outperform that of the original ones. We expect that the SCC will contribute an efficient solution to the related studies.

  9. Diets of three species of anurans from the cache creek watershed, California, USA

    Science.gov (United States)

    Hothem, R.L.; Meckstroth, A.M.; Wegner, K.E.; Jennings, M.R.; Crayon, J.J.

    2009-01-01

    We evaluated the diets of three sympatric anuran species, the native Northern Pacific Treefrog, Pseudacris regilla, and Foothill Yellow-Legged Frog, Rana boylii, and the introduced American Bullfrog, Lithobates catesbeianus, based on stomach contents of frogs collected at 36 sites in 1997 and 1998. This investigation was part of a study of mercury bioaccumulation in the biota of the Cache Creek Watershed in north-central California, an area affected by mercury contamination from natural sources and abandoned mercury mines. We collected R. boylii at 22 sites, L. catesbeianus at 21 sites, and P. regilla at 13 sites. We collected both L. catesbeianus and R. boylii at nine sites and all three species at five sites. Pseudacris regilla had the least aquatic diet (100% of the samples had terrestrial prey vs. 5% with aquatic prey), followed by R. boylii (98% terrestrial, 28% aquatic), and L. catesbeianus, which had similar percentages of terrestrial (81%) and aquatic prey (74%). Observed predation by L. catesbeianus on R. boylii may indicate that interaction between these two species is significant. Based on their widespread abundance and their preference for aquatic foods, we suggest that, where present, L. catesbeianus should be the species of choice for all lethal biomonitoring of mercury in amphibians. Copyright ?? 2009 Society for the Study of Amphibians and Reptiles.

  10. Data Rate Estimation for Wireless Core-to-Cache Communication in Multicore CPUs

    Directory of Open Access Journals (Sweden)

    M. Komar

    2015-01-01

    Full Text Available In this paper, a principal architecture of common purpose CPU and its main components are discussed, CPUs evolution is considered and drawbacks that prevent future CPU development are mentioned. Further, solutions proposed so far are addressed and a new CPU architecture is introduced. The proposed architecture is based on wireless cache access that enables a reliable interaction between cores in multicore CPUs using terahertz band, 0.1-10THz. The presented architecture addresses the scalability problem of existing processors and may potentially allow to scale them to tens of cores. As in-depth analysis of the applicability of the suggested architecture requires accurate prediction of traffic in current and next generations of processors, we consider a set of approaches for traffic estimation in modern CPUs discussing their benefits and drawbacks. The authors identify traffic measurements by using existing software tools as the most promising approach for traffic estimation, and they use Intel Performance Counter Monitor for this purpose. Three types of CPU loads are considered including two artificial tests and background system load. For each load type the amount of data transmitted through the L2-L3 interface is reported for various input parameters including the number of active cores and their dependences on the number of cores and operational frequency.

  11. AirCache: A Crowd-Based Solution for Geoanchored Floating Data

    Directory of Open Access Journals (Sweden)

    Armir Bujari

    2016-01-01

    Full Text Available The Internet edge has evolved from a simple consumer of information and data to eager producer feeding sensed data at a societal scale. The crowdsensing paradigm is a representative example which has the potential to revolutionize the way we acquire and consume data. Indeed, especially in the era of smartphones, the geographical and temporal scopus of data is often local. For instance, users’ queries are more and more frequently about a nearby object, event, person, location, and so forth. These queries could certainly be processed and answered locally, without the need for contacting a remote server through the Internet. In this scenario, the data is alimented (sensed by the users and, as a consequence, data lifetime is limited by human organizational factors (e.g., mobility. From this basis, data survivability in the Area of Interest (AoI is crucial and, if not guaranteed, could undermine system deployment. Addressing this scenario, we discuss and contribute with a novel protocol named AirCache, whose aim is to guarantee data availability in the AoI while at the same time reducing the data access costs at the network edges. We assess our proposal through a simulation analysis showing that our approach effectively fulfills its design objectives.

  12. Smart Collaborative Caching for Information-Centric IoT in Fog Computing

    Directory of Open Access Journals (Sweden)

    Fei Song

    2017-11-01

    Full Text Available The significant changes enabled by the fog computing had demonstrated that Internet of Things (IoT urgently needs more evolutional reforms. Limited by the inflexible design philosophy; the traditional structure of a network is hard to meet the latest demands. However, Information-Centric Networking (ICN is a promising option to bridge and cover these enormous gaps. In this paper, a Smart Collaborative Caching (SCC scheme is established by leveraging high-level ICN principles for IoT within fog computing paradigm. The proposed solution is supposed to be utilized in resource pooling, content storing, node locating and other related situations. By investigating the available characteristics of ICN, some challenges of such combination are reviewed in depth. The details of building SCC, including basic model and advanced algorithms, are presented based on theoretical analysis and simplified examples. The validation focuses on two typical scenarios: simple status inquiry and complex content sharing. The number of clusters, packet loss probability and other parameters are also considered. The analytical results demonstrate that the performance of our scheme, regarding total packet number and average transmission latency, can outperform that of the original ones. We expect that the SCC will contribute an efficient solution to the related studies.

  13. Políticas de reemplazo en la caché de web

    Directory of Open Access Journals (Sweden)

    Carlos Quesada Sánchez

    2006-05-01

    Full Text Available La web es el mecanismo de comunicación más utilizado en la actualidad debido a su flexibilidad y a la oferta casi interminable de herramientas para navegarla. Esto hace que día con día se agreguen alrededor de un millón de páginas en ella. De esta manera, es entonces la biblioteca más grande, con recursos textuales y de multimedia, que jamás se haya visto antes. Eso sí, es una biblioteca distribuida alrededor de todos los servidores que contienen esa información. Como fuente de consulta, es importante que la recuperación de los datos sea eficiente. Para ello existe el Web Caching, técnica mediante la cual se almacenan temporalmente algunos datos de la web en los servidores locales, de manera que no haya que pedirlos al servidor remoto cada vez que un usuario los solicita. Empero, la cantidad de memoria disponible en los servidores locales para almacenar esa información es limitada: hay que decidir cuáles objetos de la web se almacenan y cuáles no. Esto da pie a varias políticas de reemplazo que se explorarán en este artículo. Mediante un experimento de peticiones reales de la Web, compararemos el desempeño de estas técnicas.

  14. Experimental Evaluation of a High Speed Flywheel for an Energy Cache System

    Science.gov (United States)

    Haruna, J.; Murai, K.; Itoh, J.; Yamada, N.; Hirano, Y.; Fujimori, T.; Homma, T.

    2011-03-01

    A flywheel energy cache system (FECS) is a mechanical battery that can charge/discharge electricity by converting it into the kinetic energy of a rotating flywheel, and vice versa. Compared to a chemical battery, a FECS has great advantages in durability and lifetime, especially in hot or cold environments. Design simulations of the FECS were carried out to clarify the effects of the composition and dimensions of the flywheel rotor on the charge/discharge performance. The rotation speed of a flywheel is limited by the strength of the materials from which it is constructed. Three materials, carbon fiber-reinforced polymer (CFRP), Cr-Mo steel, and a Mg alloy were examined with respect to the required weight and rotation speed for a 3 MJ (0.8 kWh) charging/discharging energy, which is suitable for an FECS operating with a 3-5 kW photovoltaic device in an ordinary home connected to a smart grid. The results demonstrate that, for a stationary 3 MJ FECS, Cr-Mo steel was the most cost-effective, but also the heaviest, Mg-alloy had a good balance of rotation speed and weight, which should result in reduced mechanical loss and enhanced durability and lifetime of the system, and CFRP should be used for applications requiring compactness and a higher energy density. Finally, a high-speed prototype FW was analyzed to evaluate its fundamental characteristics both under acceleration and in the steady state.

  15. Experimental Evaluation of a High Speed Flywheel for an Energy Cache System

    International Nuclear Information System (INIS)

    Haruna, J; Itoh, J; Murai, K; Yamada, N; Hirano, Y; Homma, T; Fujimori, T

    2011-01-01

    A flywheel energy cache system (FECS) is a mechanical battery that can charge/discharge electricity by converting it into the kinetic energy of a rotating flywheel, and vice versa. Compared to a chemical battery, a FECS has great advantages in durability and lifetime, especially in hot or cold environments. Design simulations of the FECS were carried out to clarify the effects of the composition and dimensions of the flywheel rotor on the charge/discharge performance. The rotation speed of a flywheel is limited by the strength of the materials from which it is constructed. Three materials, carbon fiber-reinforced polymer (CFRP), Cr-Mo steel, and a Mg alloy were examined with respect to the required weight and rotation speed for a 3 MJ (0.8 kWh) charging/discharging energy, which is suitable for an FECS operating with a 3-5 kW photovoltaic device in an ordinary home connected to a smart grid. The results demonstrate that, for a stationary 3 MJ FECS, Cr-Mo steel was the most cost-effective, but also the heaviest, Mg-alloy had a good balance of rotation speed and weight, which should result in reduced mechanical loss and enhanced durability and lifetime of the system, and CFRP should be used for applications requiring compactness and a higher energy density. Finally, a high-speed prototype FW was analyzed to evaluate its fundamental characteristics both under acceleration and in the steady state.

  16. Leveraging KVM Events to Detect Cache-Based Side Channel Attacks in a Virtualization Environment

    Directory of Open Access Journals (Sweden)

    Ady Wahyudi Paundu

    2018-01-01

    Full Text Available Cache-based side channel attack (CSCa techniques in virtualization systems are becoming more advanced, while defense methods against them are still perceived as nonpractical. The most recent CSCa variant called Flush + Flush has showed that the current detection methods can be easily bypassed. Within this work, we introduce a novel monitoring approach to detect CSCa operations inside a virtualization environment. We utilize the Kernel Virtual Machine (KVM event data in the kernel and process this data using a machine learning technique to identify any CSCa operation in the guest Virtual Machine (VM. We evaluate our approach using Receiver Operating Characteristic (ROC diagram of multiple attack and benign operation scenarios. Our method successfully separate the CSCa datasets from the non-CSCa datasets, on both trained and nontrained data scenarios. The successful classification also include the Flush + Flush attack scenario. We are also able to explain the classification results by extracting the set of most important features that separate both classes using their Fisher scores and show that our monitoring approach can work to detect CSCa in general. Finally, we evaluate the overhead impact of our CSCa monitoring method and show that it has a negligible computation overhead on the host and the guest VM.

  17. A Query Cache Tool for Optimizing Repeatable and Parallel OLAP Queries

    Science.gov (United States)

    Santos, Ricardo Jorge; Bernardino, Jorge

    On-line analytical processing against data warehouse databases is a common form of getting decision making information for almost every business field. Decision support information oftenly concerns periodic values based on regular attributes, such as sales amounts, percentages, most transactioned items, etc. This means that many similar OLAP instructions are periodically repeated, and simultaneously, between the several decision makers. Our Query Cache Tool takes advantage of previously executed queries, storing their results and the current state of the data which was accessed. Future queries only need to execute against the new data, inserted since the queries were last executed, and join these results with the previous ones. This makes query execution much faster, because we only need to process the most recent data. Our tool also minimizes the execution time and resource consumption for similar queries simultaneously executed by different users, putting the most recent ones on hold until the first finish and returns the results for all of them. The stored query results are held until they are considered outdated, then automatically erased. We present an experimental evaluation of our tool using a data warehouse based on a real-world business dataset and use a set of typical decision support queries to discuss the results, showing a very high gain in query execution time.

  18. Smart Collaborative Caching for Information-Centric IoT in Fog Computing

    Science.gov (United States)

    Song, Fei; Ai, Zheng-Yang; Li, Jun-Jie; Zhang, Hong-Ke

    2017-01-01

    The significant changes enabled by the fog computing had demonstrated that Internet of Things (IoT) urgently needs more evolutional reforms. Limited by the inflexible design philosophy; the traditional structure of a network is hard to meet the latest demands. However, Information-Centric Networking (ICN) is a promising option to bridge and cover these enormous gaps. In this paper, a Smart Collaborative Caching (SCC) scheme is established by leveraging high-level ICN principles for IoT within fog computing paradigm. The proposed solution is supposed to be utilized in resource pooling, content storing, node locating and other related situations. By investigating the available characteristics of ICN, some challenges of such combination are reviewed in depth. The details of building SCC, including basic model and advanced algorithms, are presented based on theoretical analysis and simplified examples. The validation focuses on two typical scenarios: simple status inquiry and complex content sharing. The number of clusters, packet loss probability and other parameters are also considered. The analytical results demonstrate that the performance of our scheme, regarding total packet number and average transmission latency, can outperform that of the original ones. We expect that the SCC will contribute an efficient solution to the related studies. PMID:29104219

  19. Percolation-theoretic bounds on the cache size of nodes in mobile opportunistic networks.

    Science.gov (United States)

    Yuan, Peiyan; Wu, Honghai; Zhao, Xiaoyan; Dong, Zhengnan

    2017-07-18

    The node buffer size has a large influence on the performance of Mobile Opportunistic Networks (MONs). This is mainly because each node should temporarily cache packets to deal with the intermittently connected links. In this paper, we study fundamental bounds on node buffer size below which the network system can not achieve the expected performance such as the transmission delay and packet delivery ratio. Given the condition that each link has the same probability p to be active in the next time slot when the link is inactive and q to be inactive when the link is active, there exists a critical value p c from a percolation perspective. If p > p c , the network is in the supercritical case, where we found that there is an achievable upper bound on the buffer size of nodes, independent of the inactive probability q. When p network is in the subcritical case, and there exists a closed-form solution for buffer occupation, which is independent of the size of the network.

  20. Aristotle: A performance Impact Indicator for the OpenCL Kernels Using Local Memory

    Directory of Open Access Journals (Sweden)

    Jianbin Fang

    2014-01-01

    Full Text Available Due to the increasing complexity of multi/many-core architectures (with their mix of caches and scratch-pad memories and applications (with different memory access patterns, the performance of many workloads becomes increasingly variable. In this work, we address one of the main causes for this performance variability: the efficiency of the memory system. Specifically, based on an empirical evaluation driven by memory access patterns, we qualify and partially quantify the performance impact of using local memory in multi/many-core processors. To do so, we systematically describe memory access patterns (MAPs in an application-agnostic manner. Next, for each identified MAP, we use OpenCL (for portability reasons to generate two microbenchmarks: a “naive” version (without local memory and “an optimized” version (using local memory. We then evaluate both of them on typically used multi-core and many-core platforms, and we log their performance. What we eventually obtain is a local memory performance database, indexed by various MAPs and platforms. Further, we propose a set of composing rules for multiple MAPs. Thus, we can get an indicator of whether using local memory is beneficial in the presence of multiple memory access patterns. This indication can be used to either avoid the hassle of implementing optimizations with too little gain or, alternatively, give a rough prediction of the performance gain.

  1. A Novel Two-Tier Cooperative Caching Mechanism for the Optimization of Multi-Attribute Periodic Queries in Wireless Sensor Networks

    Science.gov (United States)

    Zhou, ZhangBing; Zhao, Deng; Shu, Lei; Tsang, Kim-Fung

    2015-01-01

    Wireless sensor networks, serving as an important interface between physical environments and computational systems, have been used extensively for supporting domain applications, where multiple-attribute sensory data are queried from the network continuously and periodically. Usually, certain sensory data may not vary significantly within a certain time duration for certain applications. In this setting, sensory data gathered at a certain time slot can be used for answering concurrent queries and may be reused for answering the forthcoming queries when the variation of these data is within a certain threshold. To address this challenge, a popularity-based cooperative caching mechanism is proposed in this article, where the popularity of sensory data is calculated according to the queries issued in recent time slots. This popularity reflects the possibility that sensory data are interested in the forthcoming queries. Generally, sensory data with the highest popularity are cached at the sink node, while sensory data that may not be interested in the forthcoming queries are cached in the head nodes of divided grid cells. Leveraging these cooperatively cached sensory data, queries are answered through composing these two-tier cached data. Experimental evaluation shows that this approach can reduce the network communication cost significantly and increase the network capability. PMID:26131665

  2. Distributed late-binding micro-scheduling and data caching for data-intensive workflows

    International Nuclear Information System (INIS)

    Delgado Peris, A.

    2015-01-01

    Today's world is flooded with vast amounts of digital information coming from innumerable sources. Moreover, it seems clear that this trend will only intensify in the future. Industry, society and remarkably science are not indifferent to this fact. On the contrary, they are struggling to get the most out of this data, which means that they need to capture, transfer, store and process it in a timely and efficient manner, using a wide range of computational resources. And this task is not always simple. A very representative example of the challenges posed by the management and processing of large quantities of data is that of the Large Hadron Collider experiments, which handle tens of petabytes of physics information every year. Based on the experience of one of these collaborations, we have studied the main issues involved in the management of huge volumes of data and in the completion of sizeable workflows that consume it. In this context, we have developed a general-purpose architecture for the scheduling and execution of workflows with heavy data requirements: the Task Queue. This new system builds on the late-binding overlay model, which has helped experiments to successfully overcome the problems associated to the heterogeneity and complexity of large computational grids. Our proposal introduces several enhancements to the existing systems. The execution agents of the Task Queue architecture share a Distributed Hash Table (DHT) and perform job matching and assignment cooperatively. In this way, scalability problems of centralized matching algorithms are avoided and workflow execution times are improved. Scalability makes fine-grained micro-scheduling possible and enables new functionalities, like the implementation of a distributed data cache on the execution nodes and the integration of data location information in the scheduling decisions...(Author)

  3. Evaluation of low-temperature geothermal potential in Cache Valley, Utah. Report of investigation No. 174

    Energy Technology Data Exchange (ETDEWEB)

    de Vries, J.L.

    1982-11-01

    Field work consisted of locating 90 wells and springs throughout the study area, collecting water samples for later laboratory analyses, and field measurement of pH, temperature, bicarbonate alkalinity, and electrical conductivity. Na/sup +/, K/sup +/, Ca/sup +2/, Mg/sup +2/, SiO/sub 2/, Fe, SO/sub 4//sup -2/, Cl/sup -/, F/sup -/, and total dissolved solids were determined in the laboratory. Temperature profiles were measured in 12 additional, unused walls. Thermal gradients calculated from the profiles were approximately the same as the average for the Basin and Range province, about 35/sup 0/C/km. One well produced a gradient of 297/sup 0/C/km, most probably as a result of a near-surface occurrence of warm water. Possible warm water reservoir temperatures were calculated using both the silica and the Na-K-Ca geothermometers, with the results averaging about 50 to 100/sup 0/C. If mixing calculations were applied, taking into account the temperatures and silica contents of both warm springs or wells and the cold groundwater, reservoir temperatures up to about 200/sup 0/C were indicated. Considering measured surface water temperatures, calculated reservoir temperatures, thermal gradients, and the local geology, most of the Cache Valley, Utah area is unsuited for geothermal development. However, the areas of North Logan, Benson, and Trenton were found to have anomalously warm groundwater in comparison to the background temperature of 13.0/sup 0/C for the study area. The warm water has potential for isolated energy development but is not warm enough for major commercial development.

  4. Texture analysis for mapping Tamarix parviflora using aerial photographs along the Cache Creek, California.

    Science.gov (United States)

    Ge, Shaokui; Carruthers, Raymond; Gong, Peng; Herrera, Angelica

    2006-03-01

    Natural color photographs were used to detect the coverage of saltcedar, Tamarix parviflora, along a 40 km portion of Cache Creek near Woodland, California. Historical aerial photographs from 2001 were retrospectively evaluated and compared with actual ground-based information to assess accuracy of the assessment process. The color aerial photos were sequentially digitized, georeferenced, classified using color and texture methods, and mosaiced into maps for field use. Eight types of ground cover (Tamarix, agricultural crops, roads, rocks, water bodies, evergreen trees, non-evergreen trees and shrubs (excluding Tamarix)) were selected from the digitized photos for separability analysis and supervised classification. Due to color similarities among the eight cover types, the average separability, based originally only on color, was very low. The separability was improved significantly through the inclusion of texture analysis. Six types of texture measures with various window sizes were evaluated. The best texture was used as an additional feature along with the color, for identifying Tamarix. A total of 29 color photographs were processed to detect Tamarix infestations using a combination of the original digital images and optimal texture features. It was found that the saltcedar covered a total of 3.96 km(2) (396 hectares) within the study area. For the accuracy assessment, 95 classified samples from the resulting map were checked in the field with a global position system (GPS) unit to verify Tamarix presence. The producer's accuracy was 77.89%. In addition, 157 independently located ground sites containing saltcedar were compared with the classified maps, producing a user's accuracy of 71.33%.

  5. Using caching and optimization techniques to improve performance of the Ensembl website

    Directory of Open Access Journals (Sweden)

    Smith James A

    2010-05-01

    Full Text Available Abstract Background The Ensembl web site has provided access to genomic information for almost 10 years. During this time the amount of data available through Ensembl has grown dramatically. At the same time, the World Wide Web itself has become a dramatically more important component of the scientific workflow and the way that scientists share and access data and scientific information. Since 2000, the Ensembl web interface has had three major updates and numerous smaller updates. These have largely been in response to expanding data types and valuable representations of existing data types. In 2007 it was realised that a radical new approach would be required in order to serve the project's future requirements, and development therefore focused on identifying suitable web technologies for implementation in the 2008 site redesign. Results By comparing the Ensembl website to well-known "Web 2.0" sites, we were able to identify two main areas in which cutting-edge technologies could be advantageously deployed: server efficiency and interface latency. We then evaluated the performance of the existing site using browser-based tools and Apache benchmarking, and selected appropriate technologies to overcome any issues found. Solutions included optimization of the Apache web server, introduction of caching technologies and widespread implementation of AJAX code. These improvements were successfully deployed on the Ensembl website in late 2008 and early 2009. Conclusions Web 2.0 technologies provide a flexible and efficient way to access the terabytes of data now available from Ensembl, enhancing the user experience through improved website responsiveness and a rich, interactive interface.

  6. Suspense, culpa y cintas de vídeo. Caché/Escondido de Michael Haneke

    Directory of Open Access Journals (Sweden)

    Miguel Martínez-Cabeza

    2011-12-01

    Full Text Available Caché/Escondido (2005 representa dentro de la filmografía de Michael Haneke el ejemplo más destacado de síntesis de los planteamientos formales e ideológicos del cineasta austriaco. Este artículo analiza el filme como manifiesto cinematográfico y como explotación de las convenciones genéricas para construir un modelo de espectador reflexivo. La investigación del modo en que el director plantea y abandona las técnicas del suspense aporta claves para explicar el éxito casi unánime de crítica y la respuesta mucho menos homogénea de las audiencias. El desencadenante de la trama, unas cintas de vídeo que reciben los Laurent, es alusión directa a Carretera Perdida (1997 de David Lynch; no obstante, el misterio acerca del autor de la videovigilancia pierde interés en relación al sentimiento de culpa que desencadena en el protagonista. El episodio infantil de celos y venganza hacia un niño argelino y la actitud del Georges adulto representan una alegoría de la relación de Francia con su pasado colonial que tampoco cierra la narración de Haneke. Es precisamente la apertura formal con que el filme (desestructura cuestiones actuales como el límite entre la responsabilidad individual y colectiva lo que conforma un espectador tan distanciado de la diégesis como consciente de su propio papel de observador.

  7. Using Memory in the Right Way to Accelerate Big Data Processing

    Institute of Scientific and Technical Information of China (English)

    阎栋; 尹绪森; 连城; 钟翔; 周鑫; 吴甘沙

    2015-01-01

    Big data processing is becoming a standout part of data center computation. However, latest research has indicated that big data workloads cannot make full use of modern memory systems. We find that the dramatic inefficiency of the big data processing is from the enormous amount of cache misses and stalls of the depended memory accesses. In this paper, we introduce two optimizations to tackle these problems. The first one is the slice-and-merge strategy, which reduces the cache miss rate of the sort procedure. The second optimization is direct-memory-access, which reforms the data structure used in key/value storage. These optimizations are evaluated with both micro-benchmarks and the real-world benchmark HiBench. The results of our micro-benchmarks clearly demonstrate the effectiveness of our optimizations in terms of hardware event counts; and the additional results of HiBench show the 1.21X average speedup on the application-level. Both results illustrate that careful hardware/software co-design will improve the memory efficiency of big data processing. Our work has already been integrated into Intel distribution for Apache Hadoop.

  8. Cognitive memory.

    Science.gov (United States)

    Widrow, Bernard; Aragon, Juan Carlos

    2013-05-01

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

  9. Evaluation of External Memory Access Performance on a High-End FPGA Hybrid Computer

    Directory of Open Access Journals (Sweden)

    Konstantinos Kalaitzis

    2016-10-01

    Full Text Available The motivation of this research was to evaluate the main memory performance of a hybrid super computer such as the Convey HC-x, and ascertain how the controller performs in several access scenarios, vis-à-vis hand-coded memory prefetches. Such memory patterns are very useful in stencil computations. The theoretical bandwidth of the memory of the Convey is compared with the results of our measurements. The accurate study of the memory subsystem is particularly useful for users when they are developing their application-specific personality. Experiments were performed to measure the bandwidth between the coprocessor and the memory subsystem. The experiments aimed mainly at measuring the reading access speed of the memory from Application Engines (FPGAs. Different ways of accessing data were used in order to find the most efficient way to access memory. This way was proposed for future work in the Convey HC-x. When performing a series of accesses to memory, non-uniform latencies occur. The Memory Controller of the Convey HC-x in the coprocessor attempts to cover this latency. We measure memory efficiency as a ratio of the number of memory accesses and the number of execution cycles. The result of this measurement converges to one in most cases. In addition, we performed experiments with hand-coded memory accesses. The analysis of the experimental results shows how the memory subsystem and Memory Controllers work. From this work we conclude that the memory controllers do an excellent job, largely because (transparently to the user they seem to cache large amounts of data, and hence hand-coding is not needed in most situations.

  10. Adapting Memory Hierarchies for Emerging Datacenter Interconnects

    Institute of Scientific and Technical Information of China (English)

    江涛; 董建波; 侯锐; 柴琳; 张立新; 孙凝晖; 田斌

    2015-01-01

    Efficient resource utilization requires that emerging datacenter interconnects support both high performance communication and efficient remote resource sharing. These goals require that the network be more tightly coupled with the CPU chips. Designing a new interconnection technology thus requires considering not only the interconnection itself, but also the design of the processors that will rely on it. In this paper, we study memory hierarchy implications for the design of high-speed datacenter interconnects—particularly as they affect remote memory access—and we use PCIe as the vehicle for our investigations. To that end, we build three complementary platforms: a PCIe-interconnected prototype server with which we measure and analyze current bottlenecks; a software simulator that lets us model microarchitectural and cache hierarchy changes;and an FPGA prototype system with a streamlined switchless customized protocol Thunder with which we study hardware optimizations outside the processor. We highlight several architectural modifications to better support remote memory access and communication, and quantify their impact and limitations.

  11. Memory Modulation

    NARCIS (Netherlands)

    Roozendaal, Benno; McGaugh, James L.

    2011-01-01

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

  12. The Caregiver Contribution to Heart Failure Self-Care (CACHS): Further Psychometric Testing of a Novel Instrument.

    Science.gov (United States)

    Buck, Harleah G; Harkness, Karen; Ali, Muhammad Usman; Carroll, Sandra L; Kryworuchko, Jennifer; McGillion, Michael

    2017-04-01

    Caregivers (CGs) contribute important assistance with heart failure (HF) self-care, including daily maintenance, symptom monitoring, and management. Until CGs' contributions to self-care can be quantified, it is impossible to characterize it, account for its impact on patient outcomes, or perform meaningful cost analyses. The purpose of this study was to conduct psychometric testing and item reduction on the recently developed 34-item Caregiver Contribution to Heart Failure Self-care (CACHS) instrument using classical and item response theory methods. Fifty CGs (mean age 63 years ±12.84; 70% female) recruited from a HF clinic completed the CACHS in 2014 and results evaluated using classical test theory and item response theory. Items would be deleted for low (.95) endorsement, low (.7) corrected item-total correlations, significant pairwise correlation coefficients, floor or ceiling effects, relatively low latent trait and item information function levels ( .5), and differential item functioning. After analysis, 14 items were excluded, resulting in a 20-item instrument (self-care maintenance eight items; monitoring seven items; and management five items). Most items demonstrated moderate to high discrimination (median 2.13, minimum .77, maximum 5.05), and appropriate item difficulty (-2.7 to 1.4). Internal consistency reliability was excellent (Cronbach α = .94, average inter-item correlation = .41) with no ceiling effects. The newly developed 20-item version of the CACHS is supported by rigorous instrument development and represents a novel instrument to measure CGs' contribution to HF self-care. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  13. An evaluation of memory accuracy in food hoarding marsh tits Poecile palustris--how accurate are they compared to humans?

    Science.gov (United States)

    Brodin, Anders; Urhan, A Utku

    2013-07-01

    Laboratory studies of scatter hoarding birds have become a model system for spatial memory studies. Considering that such birds are known to have a good spatial memory, recovery success in lab studies seems low. In parids (titmice and chickadees) typically ranging between 25 and 60% if five seeds are cached in 50-128 available caching sites. Since these birds store many thousands of food items in nature in one autumn one might expect that they should easily retrieve five seeds in a laboratory where they know the environment with its caching sites in detail. We designed a laboratory set up to be as similar as possible with previous studies and trained wild caught marsh tits Poecile palustris to store and retrieve in this set up. Our results agree closely with earlier studies, of the first ten looks around 40% were correct when the birds had stored five seeds in 100 available sites both 5 and 24h after storing. The cumulative success curve suggests high success during the first 15 looks where after it declines. Humans performed much better, in the first five looks most subjects were 100% correct. We discuss possible reasons for why the birds were not doing better. Copyright © 2013 Elsevier B.V. All rights reserved.

  14. Avaliação do compartilhamento das memórias cache no desempenho de arquiteturas multi-core

    OpenAIRE

    Marco Antonio Zanata Alves

    2009-01-01

    No atual contexto de inovações em multi-core, em que as novas tecnologias de integração estão fornecendo um número crescente de transistores por chip, o estudo de técnicas de aumento de vazão de dados é de suma importância para os atuais e futuros processadores multi-core e many-core. Com a contínua demanda por desempenho computacional, as memórias cache vêm sendo largamente adotadas nos diversos tipos de projetos arquiteturais de computadores. Os atuais processadores disponíveis no mercado a...

  15. A study on the effectiveness of lockup-free caches for a Reduced Instruction Set Computer (RISC) processor

    OpenAIRE

    Tharpe, Leonard.

    1992-01-01

    Approved for public release; distribution is unlimited This thesis presents a simulation and analysis of the Reduced Instruction Set Computer (RISC) architecture and the effects on RISC performance of a lockup-free cache interface. RISC architectures achieve high performance by having a small, but sufficient, instruction set with most instructions executing in one clock cycle. Current RISC performance range from 1.5 to 2.0 CPI. The goal of RISC is to attain a CPI of 1.0. The major hind...

  16. Memory Dysfunction

    Science.gov (United States)

    Matthews, Brandy R.

    2015-01-01

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

  17. Declarative memory.

    Science.gov (United States)

    Riedel, Wim J; Blokland, Arjan

    2015-01-01

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

  18. Quantum memory Quantum memory

    Science.gov (United States)

    Le Gouët, Jean-Louis; Moiseev, Sergey

    2012-06-01

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

  19. Looking for episodic memory in animals and young children: prospects for a new minimalism.

    Science.gov (United States)

    Clayton, Nicola S; Russell, James

    2009-09-01

    Because animals and young children cannot be interrogated about their experiences it is difficult to conduct research into their episodic memories. The approach to this issue adopted by Clayton and Dickinson [Clayton, N. S., & Dickinson, A. (1998). Episodic-like memory during cache recovery by scrub jays. Nature, 395, 272-274] was to take a conceptually minimalist definition of episodic memory, in terms of integrating information about what was done where and when [Tulving, E. (1972). Episodic and semantic memory. In E. Tulving, & W. Donaldson (Eds.), Organisation of memory (pp. 381-403). New York: Academic Press], and to refer to such memories as 'episodic-like'. Some claim, however, that because animals supposedly lack the conceptual abilities necessary for episodic recall one should properly call these memories 'semantic'. We address this debate with a novel approach to episodic memory, which is minimalist insofar as it focuses on the non-conceptual content of a re-experienced situation. It rests on Kantian assumptions about the necessary 'perspectival' features of any objective experience or re-experience. We show how adopting this perspectival approach can render an episodic interpretation of the animal data more plausible and can also reveal patterns in the mosaic of developmental evidence for episodic memory in humans.

  20. From the Island of the Blue Dolphins: A unique 19th century cache feature from San Nicolas Island, California

    Science.gov (United States)

    Erlandson, Jon M.; Thomas-Barnett, Lisa; Vellanoweth, René L.; Schwartz, Steven J.; Muhs, Daniel R.

    2013-01-01

    A cache feature salvaged from an eroding sea cliff on San Nicolas Island produced two redwood boxes containing more than 200 artifacts of Nicoleño, Native Alaskan, and Euro-American origin. Outside the boxes were four asphaltum-coated baskets, abalone shells, a sandstone dish, and a hafted stone knife. The boxes, made from split redwood planks, contained a variety of artifacts and numerous unmodified bones and teeth from marine mammals, fish, birds, and large land mammals. Nicoleño-style artifacts include 11 knives with redwood handles and stone blades, stone projectile points, steatite ornaments and effigies, a carved stone pipe, abraders and burnishing stones, bird bone whistles, bone and shell pendants, abalone shell dishes, and two unusual barbed shell fishhooks. Artifacts of Native Alaskan style include four bone toggling harpoons, two unilaterally barbed bone harpoon heads, bone harpoon fore-shafts, a ground slate blade, and an adze blade. Objects of Euro-American origin or materials include a brass button, metal harpoon blades, and ten flaked glass bifaces. The contents of the cache feature, dating to the early-to-mid nineteenth century, provide an extraordinary window on a time of European expansion and global economic development that created unique cultural interactions and social transformations.

  1. XRootd, disk-based, caching-proxy for optimization of data-access, data-placement and data-replication

    CERN Document Server

    Tadel, Matevz

    2013-01-01

    Following the smashing success of XRootd-based USCMS data-federation, AAA project investigated extensions of the federation architecture by developing two sample implementations of an XRootd, disk-based, caching-proxy. The first one simply starts fetching a whole file as soon as a file-open request is received and is suitable when completely random file access is expected or it is already known that a whole file be read. The second implementation supports on-demand downloading of partial files. Extensions to the Hadoop file-system have been developed to allow foran immediate fallback to network access when local HDFS storage fails to provide the requested block. Tools needed to analyze and to tweak block replication factors and to inject downloaded blocks into a running HDFS installation have also been developed. Both cache implementations are in operation at UCSD and several tests were also performed at UNL and UW-M. Operational experience and applications to automatic storage healing and opportunistic compu...

  2. Memory design

    DEFF Research Database (Denmark)

    Tanderup, Sisse

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

  3. Disputed Memory

    DEFF Research Database (Denmark)

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

  4. Main Memory

    OpenAIRE

    Boncz, Peter; Liu, Lei; Özsu, M.

    2008-01-01

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

  5. Design of a memory-access controller with 3.71-times-enhanced energy efficiency for Internet-of-Things-oriented nonvolatile microcontroller unit

    Science.gov (United States)

    Natsui, Masanori; Hanyu, Takahiro

    2018-04-01

    In realizing a nonvolatile microcontroller unit (MCU) for sensor nodes in Internet-of-Things (IoT) applications, it is important to solve the data-transfer bottleneck between the central processing unit (CPU) and the nonvolatile memory constituting the MCU. As one circuit-oriented approach to solving this problem, we propose a memory access minimization technique for magnetoresistive-random-access-memory (MRAM)-embedded nonvolatile MCUs. In addition to multiplexing and prefetching of memory access, the proposed technique realizes efficient instruction fetch by eliminating redundant memory access while considering the code length of the instruction to be fetched and the transition of the memory address to be accessed. As a result, the performance of the MCU can be improved while relaxing the performance requirement for the embedded MRAM, and compact and low-power implementation can be performed as compared with the conventional cache-based one. Through the evaluation using a system consisting of a general purpose 32-bit CPU and embedded MRAM, it is demonstrated that the proposed technique increases the peak efficiency of the system up to 3.71 times, while a 2.29-fold area reduction is achieved compared with the cache-based one.

  6. What-where-when memory in magpies (Pica pica).

    Science.gov (United States)

    Zinkivskay, Ann; Nazir, Farrah; Smulders, Tom V

    2009-01-01

    Some animals have been shown to be able to remember which type of food they hoarded or encountered in which location and how long ago (what-where-when memory). In this study, we test whether magpies (Pica pica) also show evidence of remembering these different aspects of a past episode. Magpies hid red- and blue-dyed pellets of scrambled eggs in a large tray containing wood shavings. They were allowed to make as many caches as they wanted. The birds were then returned either the same day or the next day to retrieve the pellets. If they returned the same day, one colour of pellets was replaced with wooden beads of similar size and colour, while if they returned the next day this would happen to the other colour. Over just a few trials, the birds learned to only search for the food pellets, and ignore the beads, of the appropriate colour for the given retention interval. A probe trial in which all items were removed showed that the birds persisted in searching for the pellets and not the beads. This shows that magpies can remember which food item they hoarded where, and when, even if the food items only differ from each other in their colour and are dispersed throughout a continuous caching substrate.

  7. Design Example of Useful Memory Latency for Developing a Hazard Preventive Pipeline High-Performance Embedded-Microprocessor

    Directory of Open Access Journals (Sweden)

    Ching-Hwa Cheng

    2013-01-01

    Full Text Available The existence of structural, control, and data hazards presents a major challenge in designing an advanced pipeline/superscalar microprocessor. An efficient memory hierarchy cache-RAM-Disk design greatly enhances the microprocessor's performance. However, there are complex relationships among the memory hierarchy and the functional units in the microprocessor. Most past architectural design simulations focus on the instruction hazard detection/prevention scheme from the viewpoint of function units. This paper emphasizes that additional inboard memory can be well utilized to handle the hazardous conditions. When the instruction meets hazardous issues, the memory latency can be utilized to prevent performance degradation due to the hazard prevention mechanism. By using the proposed technique, a better architectural design can be rapidly validated by an FPGA at the start of the design stage. In this paper, the simulation results prove that our proposed methodology has a better performance and less power consumption compared to the conventional hazard prevention technique.

  8. Review on Physically Flexible Nonvolatile Memory for Internet of Everything Electronics

    KAUST Repository

    Ghoneim, Mohamed T.

    2015-07-23

    Solid-state memory is an essential component of the digital age. With advancements in healthcare technology and the Internet of Things (IoT), the demand for ultra-dense, ultra-low-power memory is increasing. In this review, we present a comprehensive perspective on the most notable approaches to the fabrication of physically flexible memory devices. With the future goal of replacing traditional mechanical hard disks with solid-state storage devices, a fully flexible electronic system will need two basic devices: transistors and nonvolatile memory. Transistors are used for logic operations and gating memory arrays, while nonvolatile memory (NVM) devices are required for storing information in the main memory and cache storage. Since the highest density of transistors and storage structures is manifested in memories, the focus of this review is flexible NVM. Flexible NVM components are discussed in terms of their functionality, performance metrics, and reliability aspects, all of which are critical components for NVM technology to be part of mainstream consumer electronics, IoT, and advanced healthcare devices. Finally, flexible NVMs are benchmarked and future prospects are provided.

  9. Review on Physically Flexible Nonvolatile Memory for Internet of Everything Electronics

    Directory of Open Access Journals (Sweden)

    Mohamed T. Ghoneim

    2015-07-01

    Full Text Available Solid-state memory is an essential component of the digital age. With advancements in healthcare technology and the Internet of Things (IoT, the demand for ultra-dense, ultra-low-power memory is increasing. In this review, we present a comprehensive perspective on the most notable approaches to the fabrication of physically flexible memory devices. With the future goal of replacing traditional mechanical hard disks with solid-state storage devices, a fully flexible electronic system will need two basic devices: transistors and nonvolatile memory. Transistors are used for logic operations and gating memory arrays, while nonvolatile memory (NVM devices are required for storing information in the main memory and cache storage. Since the highest density of transistors and storage structures is manifested in memories, the focus of this review is flexible NVM. Flexible NVM components are discussed in terms of their functionality, performance metrics, and reliability aspects, all of which are critical components for NVM technology to be part of mainstream consumer electronics, IoT, and advanced healthcare devices. Finally, flexible NVMs are benchmarked and future prospects are provided.

  10. Review on Physically Flexible Nonvolatile Memory for Internet of Everything Electronics

    KAUST Repository

    Ghoneim, Mohamed T.; Hussain, Muhammad Mustafa

    2015-01-01

    Solid-state memory is an essential component of the digital age. With advancements in healthcare technology and the Internet of Things (IoT), the demand for ultra-dense, ultra-low-power memory is increasing. In this review, we present a comprehensive perspective on the most notable approaches to the fabrication of physically flexible memory devices. With the future goal of replacing traditional mechanical hard disks with solid-state storage devices, a fully flexible electronic system will need two basic devices: transistors and nonvolatile memory. Transistors are used for logic operations and gating memory arrays, while nonvolatile memory (NVM) devices are required for storing information in the main memory and cache storage. Since the highest density of transistors and storage structures is manifested in memories, the focus of this review is flexible NVM. Flexible NVM components are discussed in terms of their functionality, performance metrics, and reliability aspects, all of which are critical components for NVM technology to be part of mainstream consumer electronics, IoT, and advanced healthcare devices. Finally, flexible NVMs are benchmarked and future prospects are provided.

  11. Collaging Memories

    Science.gov (United States)

    Wallach, Michele

    2011-01-01

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

  12. Memory Magic.

    Science.gov (United States)

    Hartman, Thomas G.; Nowak, Norman

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

  13. Memory loss

    Science.gov (United States)

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

  14. Episodic Memories

    Science.gov (United States)

    Conway, Martin A.

    2009-01-01

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

  15. Flavor Memory

    NARCIS (Netherlands)

    Mojet, Jos; Köster, Ep

    2016-01-01

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

  16. Main Memory

    NARCIS (Netherlands)

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

    2008-01-01

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

  17. The Effects of Music on Subjects with Alzheimer and Dementia Disease in Cache Valley

    OpenAIRE

    Frost, Landon

    2013-01-01

    Music has been shown to trigger old memories and induce various levels of stress relief and relaxation. My research focused on the effects of music on subjects with Alzheimer and Dementia disease. Eleven patients were selected through an informed consent process which included permission from responsible family members. During the course of three or more visits to patients in their care centers, the subjects listened to a variety of songs. These included songs that family members thought woul...

  18. Accessing memory

    Science.gov (United States)

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

    2017-09-26

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

  19. Optimizing transformations of stencil operations for parallel object-oriented scientific frameworks on cache-based architectures

    Energy Technology Data Exchange (ETDEWEB)

    Bassetti, F.; Davis, K.; Quinlan, D.

    1998-12-31

    High-performance scientific computing relies increasingly on high-level large-scale object-oriented software frameworks to manage both algorithmic complexity and the complexities of parallelism: distributed data management, process management, inter-process communication, and load balancing. This encapsulation of data management, together with the prescribed semantics of a typical fundamental component of such object-oriented frameworks--a parallel or serial array-class library--provides an opportunity for increasingly sophisticated compile-time optimization techniques. This paper describes two optimizing transformations suitable for certain classes of numerical algorithms, one for reducing the cost of inter-processor communication, and one for improving cache utilization; demonstrates and analyzes the resulting performance gains; and indicates how these transformations are being automated.

  20. Temporal locality optimizations for stencil operations for parallel object-oriented scientific frameworks on cache-based architectures

    Energy Technology Data Exchange (ETDEWEB)

    Bassetti, F.; Davis, K.; Quinlan, D.

    1998-12-01

    High-performance scientific computing relies increasingly on high-level large-scale object-oriented software frameworks to manage both algorithmic complexity and the complexities of parallelism: distributed data management, process management, inter-process communication, and load balancing. This encapsulation of data management, together with the prescribed semantics of a typical fundamental component of such object-oriented frameworks--a parallel or serial array-class library--provides an opportunity for increasingly sophisticated compile-time optimization techniques. This paper describes a technique for introducing cache blocking suitable for certain classes of numerical algorithms, demonstrates and analyzes the resulting performance gains, and indicates how this optimization transformation is being automated.

  1. Contrasting patterns of survival and dispersal in multiple habitats reveal an ecological trap in a food-caching bird.

    Science.gov (United States)

    Norris, D Ryan; Flockhart, D T Tyler; Strickland, Dan

    2013-11-01

    A comprehensive understanding of how natural and anthropogenic variation in habitat influences populations requires long-term information on how such variation affects survival and dispersal throughout the annual cycle. Gray jays Perisoreus canadensis are widespread boreal resident passerines that use cached food to survive over the winter and to begin breeding during the late winter. Using multistate capture-recapture analysis, we examined apparent survival and dispersal in relation to habitat quality in a gray jay population over 34 years (1977-2010). Prior evidence suggests that natural variation in habitat quality is driven by the proportion of conifers on territories because of their superior ability to preserve cached food. Although neither adults (>1 year) nor juveniles (conifer territories, both age classes were less likely to leave high-conifer territories and, when they did move, were more likely to disperse to high-conifer territories. In contrast, survival rates were lower on territories that were adjacent to a major highway compared to territories that did not border the highway but there was no evidence for directional dispersal towards or away from highway territories. Our results support the notion that natural variation in habitat quality is driven by the proportion of coniferous trees on territories and provide the first evidence that high-mortality highway habitats can act as an equal-preference ecological trap for birds. Reproductive success, as shown in a previous study, but not survival, is sensitive to natural variation in habitat quality, suggesting that gray jays, despite living in harsh winter conditions, likely favor the allocation of limited resources towards self-maintenance over reproduction.

  2. Memory Reconsolidation.

    Science.gov (United States)

    Haubrich, Josue; Nader, Karim

    2018-01-01

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

  3. Olfactory Memory

    Science.gov (United States)

    Eichenbaum, Howard; Robitsek, R. Jonathan

    2009-01-01

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

  4. Distributed terascale volume visualization using distributed shared virtual memory

    KAUST Repository

    Beyer, Johanna

    2011-10-01

    Table 1 illustrates the impact of different distribution unit sizes, different screen resolutions, and numbers of GPU nodes. We use two and four GPUs (NVIDIA Quadro 5000 with 2.5 GB memory) and a mouse cortex EM dataset (see Figure 2) of resolution 21,494 x 25,790 x 1,850 = 955GB. The size of the virtual distribution units significantly influences the data distribution between nodes. Small distribution units result in a high depth complexity for compositing. Large distribution units lead to a low utilization of GPUs, because in the worst case only a single distribution unit will be in view, which is rendered by only a single node. The choice of an optimal distribution unit size depends on three major factors: the output screen resolution, the block cache size on each node, and the number of nodes. Currently, we are working on optimizing the compositing step and network communication between nodes. © 2011 IEEE.

  5. RTDB: A memory resident real-time object database

    International Nuclear Information System (INIS)

    Nogiec, Jerzy M.; Desavouret, Eugene

    2003-01-01

    RTDB is a fast, memory-resident object database with built-in support for distribution. It constitutes an attractive alternative for architecting real-time solutions with multiple, possibly distributed, processes or agents sharing data. RTDB offers both direct and navigational access to stored objects, with local and remote random access by object identifiers, and immediate direct access via object indices. The database supports transparent access to objects stored in multiple collaborating dispersed databases and includes a built-in cache mechanism that allows for keeping local copies of remote objects, with specifiable invalidation deadlines. Additional features of RTDB include a trigger mechanism on objects that allows for issuing events or activating handlers when objects are accessed or modified and a very fast, attribute based search/query mechanism. The overall architecture and application of RTDB in a control and monitoring system is presented

  6. Multiferroic Memories

    Directory of Open Access Journals (Sweden)

    Amritendu Roy

    2012-01-01

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

  7. Color Memory

    OpenAIRE

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

    2017-01-01

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

  8. Geochemistry of mercury and other constituents in subsurface sediment—Analyses from 2011 and 2012 coring campaigns, Cache Creek Settling Basin, Yolo County, California

    Science.gov (United States)

    Arias, Michelle R.; Alpers, Charles N.; Marvin-DiPasquale, Mark C.; Fuller, Christopher C.; Agee, Jennifer L.; Sneed, Michelle; Morita, Andrew Y.; Salas, Antonia

    2017-10-31

    Cache Creek Settling Basin was constructed in 1937 to trap sediment from Cache Creek before delivery to the Yolo Bypass, a flood conveyance for the Sacramento River system that is tributary to the Sacramento–San Joaquin Delta. Sediment management options being considered by stakeholders in the Cache Creek Settling Basin include sediment excavation; however, that could expose sediments containing elevated mercury concentrations from historical mercury mining in the watershed. In cooperation with the California Department of Water Resources, the U.S. Geological Survey undertook sediment coring campaigns in 2011–12 (1) to describe lateral and vertical distributions of mercury concentrations in deposits of sediment in the Cache Creek Settling Basin and (2) to improve constraint of estimates of the rate of sediment deposition in the basin.Sediment cores were collected in the Cache Creek Settling Basin, Yolo County, California, during October 2011 at 10 locations and during August 2012 at 5 other locations. Total core depths ranged from approximately 4.6 to 13.7 meters (15 to 45 feet), with penetration to about 9.1 meters (30 feet) at most locations. Unsplit cores were logged for two geophysical parameters (gamma bulk density and magnetic susceptibility); then, selected cores were split lengthwise. One half of each core was then photographed and archived, and the other half was subsampled. Initial subsamples from the cores (20-centimeter composite samples from five predetermined depths in each profile) were analyzed for total mercury, methylmercury, total reduced sulfur, iron speciation, organic content (as the percentage of weight loss on ignition), and grain-size distribution. Detailed follow-up subsampling (3-centimeter intervals) was done at six locations along an east-west transect in the southern part of the Cache Creek Settling Basin and at one location in the northern part of the basin for analyses of total mercury; organic content; and cesium-137, which was

  9. High Performance Programming Using Explicit Shared Memory Model on Cray T3D1

    Science.gov (United States)

    Simon, Horst D.; Saini, Subhash; Grassi, Charles

    1994-01-01

    The Cray T3D system is the first-phase system in Cray Research, Inc.'s (CRI) three-phase massively parallel processing (MPP) program. This system features a heterogeneous architecture that closely couples DEC's Alpha microprocessors and CRI's parallel-vector technology, i.e., the Cray Y-MP and Cray C90. An overview of the Cray T3D hardware and available programming models is presented. Under Cray Research adaptive Fortran (CRAFT) model four programming methods (data parallel, work sharing, message-passing using PVM, and explicit shared memory model) are available to the users. However, at this time data parallel and work sharing programming models are not available to the user community. The differences between standard PVM and CRI's PVM are highlighted with performance measurements such as latencies and communication bandwidths. We have found that the performance of neither standard PVM nor CRI s PVM exploits the hardware capabilities of the T3D. The reasons for the bad performance of PVM as a native message-passing library are presented. This is illustrated by the performance of NAS Parallel Benchmarks (NPB) programmed in explicit shared memory model on Cray T3D. In general, the performance of standard PVM is about 4 to 5 times less than obtained by using explicit shared memory model. This degradation in performance is also seen on CM-5 where the performance of applications using native message-passing library CMMD on CM-5 is also about 4 to 5 times less than using data parallel methods. The issues involved (such as barriers, synchronization, invalidating data cache, aligning data cache etc.) while programming in explicit shared memory model are discussed. Comparative performance of NPB using explicit shared memory programming model on the Cray T3D and other highly parallel systems such as the TMC CM-5, Intel Paragon, Cray C90, IBM-SP1, etc. is presented.

  10. Integrated Optical Content Addressable Memories (CAM and Optical Random Access Memories (RAM for Ultra-Fast Address Look-Up Operations

    Directory of Open Access Journals (Sweden)

    Christos Vagionas

    2017-07-01

    Full Text Available Electronic Content Addressable Memories (CAM implement Address Look-Up (AL table functionalities of network routers; however, they typically operate in the MHz regime, turning AL into a critical network bottleneck. In this communication, we demonstrate the first steps towards developing optical CAM alternatives to enable a re-engineering of AL memories. Firstly, we report on the photonic integration of Semiconductor Optical Amplifier-Mach Zehnder Interferometer (SOA-MZI-based optical Flip-Flop and Random Access Memories on a monolithic InP platform, capable of storing the binary prefix-address data-bits and the outgoing port information for next hop routing, respectively. Subsequently the first optical Binary CAM cell (B-CAM is experimentally demonstrated, comprising an InP Flip-Flop and a SOA-MZI Exclusive OR (XOR gate for fast search operations through an XOR-based bit comparison, yielding an error-free 10 Gb/s operation. This is later extended via physical layer simulations in an optical Ternary-CAM (T-CAM cell and a 4-bit Matchline (ML configuration, supporting a third state of the “logical X” value towards wildcard bits of network subnet masks. The proposed functional CAM and Random Access Memories (RAM sub-circuits may facilitate light-based Address Look-Up tables supporting search operations at 10 Gb/s and beyond, paving the way towards minimizing the disparity with the frantic optical transmission linerates, and fast re-configurability through multiple simultaneous Wavelength Division Multiplexed (WDM memory access requests.

  11. Screen-Space Normal Distribution Function Caching for Consistent Multi-Resolution Rendering of Large Particle Data

    KAUST Repository

    Ibrahim, Mohamed; Wickenhauser, Patrick; Rautek, Peter; Reina, Guido; Hadwiger, Markus

    2017-01-01

    Molecular dynamics (MD) simulations are crucial to investigating important processes in physics and thermodynamics. The simulated atoms are usually visualized as hard spheres with Phong shading, where individual particles and their local density can be perceived well in close-up views. However, for large-scale simulations with 10 million particles or more, the visualization of large fields-of-view usually suffers from strong aliasing artifacts, because the mismatch between data size and output resolution leads to severe under-sampling of the geometry. Excessive super-sampling can alleviate this problem, but is prohibitively expensive. This paper presents a novel visualization method for large-scale particle data that addresses aliasing while enabling interactive high-quality rendering. We introduce the novel concept of screen-space normal distribution functions (S-NDFs) for particle data. S-NDFs represent the distribution of surface normals that map to a given pixel in screen space, which enables high-quality re-lighting without re-rendering particles. In order to facilitate interactive zooming, we cache S-NDFs in a screen-space mipmap (S-MIP). Together, these two concepts enable interactive, scale-consistent re-lighting and shading changes, as well as zooming, without having to re-sample the particle data. We show how our method facilitates the interactive exploration of real-world large-scale MD simulation data in different scenarios.

  12. Screen-Space Normal Distribution Function Caching for Consistent Multi-Resolution Rendering of Large Particle Data

    KAUST Repository

    Ibrahim, Mohamed

    2017-08-28

    Molecular dynamics (MD) simulations are crucial to investigating important processes in physics and thermodynamics. The simulated atoms are usually visualized as hard spheres with Phong shading, where individual particles and their local density can be perceived well in close-up views. However, for large-scale simulations with 10 million particles or more, the visualization of large fields-of-view usually suffers from strong aliasing artifacts, because the mismatch between data size and output resolution leads to severe under-sampling of the geometry. Excessive super-sampling can alleviate this problem, but is prohibitively expensive. This paper presents a novel visualization method for large-scale particle data that addresses aliasing while enabling interactive high-quality rendering. We introduce the novel concept of screen-space normal distribution functions (S-NDFs) for particle data. S-NDFs represent the distribution of surface normals that map to a given pixel in screen space, which enables high-quality re-lighting without re-rendering particles. In order to facilitate interactive zooming, we cache S-NDFs in a screen-space mipmap (S-MIP). Together, these two concepts enable interactive, scale-consistent re-lighting and shading changes, as well as zooming, without having to re-sample the particle data. We show how our method facilitates the interactive exploration of real-world large-scale MD simulation data in different scenarios.

  13. A province of many eyes – Rear window and caché: when the city discloses secrets through the cinema

    Directory of Open Access Journals (Sweden)

    Eliana Kuster

    2009-06-01

    Full Text Available In the city, all people see. In the city, all people are seen. The look and its related questions – what to see, as to see, the interpretation of what is seen – Is one of the central questions of the urban space since century XIX, with the growth of the cities and the phenomenon of the multitude. The look becomes, therefore, crucial to this urban man, whom it looks to recognize in this another one – the stranger – the signals of friendship or danger. This importance of the look in the city is investigated in this essay through two films: Rear window, Alfred Hitchcock (1954, and Caché, Michael Haneke (2005. In the first movie, the personages look the city. In the other, they are seen by this city. In the two films, we have the extremities of the same process: the social life transformed into spectacle. And the cinema, playing one of its main functions: the construction of representations of the human lives in the city.

  14. Carbon stored in forest plantations of Pinus caribaea, Cupressus lusitanica and Eucalyptus deglupta in Cachí Hydroelectric Project

    Directory of Open Access Journals (Sweden)

    Marylin Rojas

    2014-06-01

    Full Text Available Forest plantations are considered the main carbon sinks thought to reduce the impact of climate change. Regarding many species, however, there is a lack of information in order to establish metrics on accumulation of biomass and carbon, principally due to the level of difficulty and the cost of quantification through direct measurement and destructive sampling. In this research, it was evaluated carbon stocks of forest plantations near the dam of hydroelectric project Cachí, which belongs to Instituto Costarricense de Electricidad. 25 unit samples were evaluated along some plantations that contain three different species. 30 Pinus caribacea trees, 14 Cupressus lusitanica and 15 Eucalyptus deglupta were extracted. The biomass was quantified by means of the destructive method. First of all, every component of the tree was weighed separately; then, sampling was obtained in order to determine the dry matter and the carbon fraction. 110 biomass samples from the three species were analyzed in laboratory, including all the components (leaves, branches, shaft, and root. The carbon fraction varied between 47,5 and 48,0 for Pinus caribacea; between 32,6 and 52,7 for Cupressus lusitanica, and beween 36,4 and 50,3% for Eucalyptus deglupta. The stored carbon was 230, 123, and 69 Mg ha-1 in plantations of P. caribaea, C. lusitanica and E. deglupta, respectively. Approximately, 75% of the stored carbon was detected in the shaft.

  15. Holographic memories

    DEFF Research Database (Denmark)

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

    1999-01-01

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

  16. Sharing Memories

    DEFF Research Database (Denmark)

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

    2018-01-01

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

  17. Memory consolidation

    NARCIS (Netherlands)

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

    2016-01-01

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

  18. Skilled Memory.

    Science.gov (United States)

    1980-11-06

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

  19. Concrete Memories

    DEFF Research Database (Denmark)

    Wiegand, Frauke Katharina

    2015-01-01

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

  20. Treadwell Memorial

    OpenAIRE

    Downey, Frances K

    2015-01-01

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

  1. SharkDB: an in-memory column-oriented storage for trajectory analysis

    KAUST Repository

    Zheng, Bolong; Wang, Haozhou; Zheng, Kai; Su, Han; Liu, Kuien; Shang, Shuo

    2017-01-01

    The last decade has witnessed the prevalence of sensor and GPS technologies that produce a high volume of trajectory data representing the motion history of moving objects. However some characteristics of trajectories such as variable lengths and asynchronous sampling rates make it difficult to fit into traditional database systems that are disk-based and tuple-oriented. Motivated by the success of column store and recent development of in-memory databases, we try to explore the potential opportunities of boosting the performance of trajectory data processing by designing a novel trajectory storage within main memory. In contrast to most existing trajectory indexing methods that keep consecutive samples of the same trajectory in the same disk page, we partition the database into frames in which the positions of all moving objects at the same time instant are stored together and aligned in main memory. We found this column-wise storage to be surprisingly well suited for in-memory computing since most frames can be stored in highly compressed form, which is pivotal for increasing the memory throughput and reducing CPU-cache miss. The independence between frames also makes them natural working units when parallelizing data processing on a multi-core environment. Lastly we run a variety of common trajectory queries on both real and synthetic datasets in order to demonstrate advantages and study the limitations of our proposed storage.

  2. SharkDB: an in-memory column-oriented storage for trajectory analysis

    KAUST Repository

    Zheng, Bolong

    2017-05-05

    The last decade has witnessed the prevalence of sensor and GPS technologies that produce a high volume of trajectory data representing the motion history of moving objects. However some characteristics of trajectories such as variable lengths and asynchronous sampling rates make it difficult to fit into traditional database systems that are disk-based and tuple-oriented. Motivated by the success of column store and recent development of in-memory databases, we try to explore the potential opportunities of boosting the performance of trajectory data processing by designing a novel trajectory storage within main memory. In contrast to most existing trajectory indexing methods that keep consecutive samples of the same trajectory in the same disk page, we partition the database into frames in which the positions of all moving objects at the same time instant are stored together and aligned in main memory. We found this column-wise storage to be surprisingly well suited for in-memory computing since most frames can be stored in highly compressed form, which is pivotal for increasing the memory throughput and reducing CPU-cache miss. The independence between frames also makes them natural working units when parallelizing data processing on a multi-core environment. Lastly we run a variety of common trajectory queries on both real and synthetic datasets in order to demonstrate advantages and study the limitations of our proposed storage.

  3. Clock generation and distribution for the 130-nm Itanium$^{R}$ 2 processor with 6-MB on-die L3 cache

    CERN Document Server

    Tam, S; Limaye, R D

    2004-01-01

    The clock generation and distribution system for the 130-nm Itanium 2 processor operates at 1.5 GHz with a skew of 24 ps. The Itanium 2 processor features 6 MB of on-die L3 cache and has a die size of 374 mm/sup 2/. Fuse-based clock de-skew enables post-silicon clock optimization to gain higher frequency. This paper describes the clock generation, global clock distribution, local clocking, and the clock skew optimization feature.

  4. 计算机高速缓冲存储器体系结构分析%Analysis of Computer Cache Memory Architecture

    Institute of Scientific and Technical Information of China (English)

    王珏

    2006-01-01

    通过对片外和片内高速缓冲存储器体系结构的总结与评价,着重分析了片内Cache与处理器核心部件、外部存储器之间的连接关系,并通过对于普林斯顿结构和哈佛结构的优缺点的讨论和分析可知,片内两级Cache结构中,一级Cache适用于哈佛结构,这样使得最接近处理器操作部件的Cache分开,消除数据引用和指令引用的冲突,远离操作部件的二级Cache则采用普林斯顿结构,可以动态调节指令和数据在其中的分配比例.这种综合的两级Cache体系结构,兼容了哈佛结构和普林斯顿结构的优势,弥补了二者的缺陷,充分发挥片内Cache的作用.

  5. Transactional Memory

    CERN Document Server

    Harris, Tim; Rajwar, Ravi

    2010-01-01

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

  6. Intentionally fabricated autobiographical memories

    OpenAIRE

    Justice, LV; Morrison, CM; Conway, MA

    2017-01-01

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

  7. STRUKTUR DAN PROSES MEMORI

    Directory of Open Access Journals (Sweden)

    Magda Bhinnety

    2015-09-01

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

  8. STRUKTUR DAN PROSES MEMORI

    OpenAIRE

    Bhinnety, Magda

    2015-01-01

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

  9. Impacto de la memoria cache en la aceleración de la ejecución de algoritmo de detección de rostros en sistemas empotrados

    Directory of Open Access Journals (Sweden)

    Alejandro Cabrera Aldaya

    2012-06-01

    Full Text Available En este trabajo se analiza el impacto de la memoria cache sobre la aceleración de la ejecución del algoritmo de detección de rostros de Viola-Jones en un sistema de procesamiento basado en el procesador Microblaze empotrado en un FPGA. Se expone el algoritmo, se describe una implementación software del mismo y se analizan sus funciones más relevantes y las características de localidad de las instrucciones y los datos. Se analiza el impacto de las memorias cache de instrucciones y de datos, tanto de sus capacidades (entre 2 y 16 kB como de tamaño de línea (de 4 y 8 palabras. Los resultados obtenidos utilizando una placa de desarrollo Spartan3A Starter Kit basada en un FPGA Spartan3A XC3S700A, con el procesador Microblaze a 62,5 MHz y 64 MB de memoria externa DDR2 a 125 MHz,  muestran un mayor impacto de la cache de instrucciones que la de datos, con valores óptimos de 8kB para la cache de instrucciones y entre 4 y 16kB para la cache de datos. Con estas memorias se alcanza una aceleración de 17 veces con relación a la ejecución del algoritmo en memoria externa. El tamaño de la línea de cache tiene poca influencia sobre la aceleración del algoritmo.

  10. CellSs: Scheduling Techniques to Better Exploit Memory Hierarchy

    Directory of Open Access Journals (Sweden)

    Pieter Bellens

    2009-01-01

    Full Text Available Cell Superscalar's (CellSs main goal is to provide a simple, flexible and easy programming approach for the Cell Broadband Engine (Cell/B.E. that automatically exploits the inherent concurrency of the applications at a task level. The CellSs environment is based on a source-to-source compiler that translates annotated C or Fortran code and a runtime library tailored for the Cell/B.E. that takes care of the concurrent execution of the application. The first efforts for task scheduling in CellSs derived from very simple heuristics. This paper presents new scheduling techniques that have been developed for CellSs for the purpose of improving an application's performance. Additionally, the design of a new scheduling algorithm is detailed and the algorithm evaluated. The CellSs scheduler takes an extension of the memory hierarchy for Cell/B.E. into account, with a cache memory shared between the SPEs. All new scheduling practices have been evaluated showing better behavior of our system.

  11. Electroconvulsive therapy and memory.

    Science.gov (United States)

    Harper, R G; Wiens, A N

    1975-10-01

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

  12. Detailed sensory memory, sloppy working memory

    NARCIS (Netherlands)

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

    2010-01-01

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

  13. Episodic memory, semantic memory, and amnesia.

    Science.gov (United States)

    Squire, L R; Zola, S M

    1998-01-01

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

  14. Optical memory

    Science.gov (United States)

    Mao, Samuel S; Zhang, Yanfeng

    2013-07-02

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

  15. Unraveling Network-induced Memory Contention: Deeper Insights with Machine Learning

    International Nuclear Information System (INIS)

    Groves, Taylor Liles; Grant, Ryan; Gonzales, Aaron; Arnold, Dorian

    2017-01-01

    Remote Direct Memory Access (RDMA) is expected to be an integral communication mechanism for future exascale systems enabling asynchronous data transfers, so that applications may fully utilize CPU resources while simultaneously sharing data amongst remote nodes. We examine Network-induced Memory Contention (NiMC) on Infiniband networks. We expose the interactions between RDMA, main-memory and cache, when applications and out-of-band services compete for memory resources. We then explore NiMCs resulting impact on application-level performance. For a range of hardware technologies and HPC workloads, we quantify NiMC and show that NiMCs impact grows with scale resulting in up to 3X performance degradation at scales as small as 8K processes even in applications that previously have been shown to be performance resilient in the presence of noise. In addition, this work examines the problem of predicting NiMC's impact on applications by leveraging machine learning and easily accessible performance counters. This approach provides additional insights about the root cause of NiMC and facilitates dynamic selection of potential solutions. Finally, we evaluated three potential techniques to reduce NiMCs impact, namely hardware offloading, core reservation and network throttling.

  16. Multiple Memory Structure Bit Reversal Algorithm Based on Recursive Patterns of Bit Reversal Permutation

    Directory of Open Access Journals (Sweden)

    K. K. L. B. Adikaram

    2014-01-01

    Full Text Available With the increasing demand for online/inline data processing efficient Fourier analysis becomes more and more relevant. Due to the fact that the bit reversal process requires considerable processing time of the Fast Fourier Transform (FFT algorithm, it is vital to optimize the bit reversal algorithm (BRA. This paper is to introduce an efficient BRA with multiple memory structures. In 2009, Elster showed the relation between the first and the second halves of the bit reversal permutation (BRP and stated that it may cause serious impact on cache performance of the computer, if implemented. We found exceptions, especially when the said index mapping was implemented with multiple one-dimensional memory structures instead of multidimensional or one-dimensional memory structure. Also we found a new index mapping, even after the recursive splitting of BRP into equal sized slots. The four-array and the four-vector versions of BRA with new index mapping reported 34% and 16% improvement in performance in relation to similar versions of Linear BRA of Elster which uses single one-dimensional memory structure.

  17. Memory, microprocessor, and ASIC

    CERN Document Server

    Chen, Wai-Kai

    2003-01-01

    System Timing. ROM/PROM/EPROM. SRAM. Embedded Memory. Flash Memories. Dynamic Random Access Memory. Low-Power Memory Circuits. Timing and Signal Integrity Analysis. Microprocessor Design Verification. Microprocessor Layout Method. Architecture. ASIC Design. Logic Synthesis for Field Programmable Gate Array (EPGA) Technology. Testability Concepts and DFT. ATPG and BIST. CAD Tools for BIST/DFT and Delay Faults.

  18. Infant Visual Recognition Memory

    Science.gov (United States)

    Rose, Susan A.; Feldman, Judith F.; Jankowski, Jeffery J.

    2004-01-01

    Visual recognition memory is a robust form of memory that is evident from early infancy, shows pronounced developmental change, and is influenced by many of the same factors that affect adult memory; it is surprisingly resistant to decay and interference. Infant visual recognition memory shows (a) modest reliability, (b) good discriminant…

  19. Nanoscale memory devices

    International Nuclear Information System (INIS)

    Chung, Andy; Deen, Jamal; Lee, Jeong-Soo; Meyyappan, M

    2010-01-01

    This article reviews the current status and future prospects for the use of nanomaterials and devices in memory technology. First, the status and continuing scaling trends of the flash memory are discussed. Then, a detailed discussion on technologies trying to replace flash in the near-term is provided. This includes phase change random access memory, Fe random access memory and magnetic random access memory. The long-term nanotechnology prospects for memory devices include carbon-nanotube-based memory, molecular electronics and memristors based on resistive materials such as TiO 2 . (topical review)

  20. Nutritional deficits during early development affect hippocampal structure and spatial memory later in life.

    Science.gov (United States)

    Pravosudov, Vladimir V; Lavenex, Pierre; Omanska, Alicja

    2005-10-01

    Development rates vary among individuals, often as a result of direct competition for food. Survival of young might depend on their learning abilities, but it remains unclear whether learning abilities are affected by nutrition during development. The authors demonstrated that compared with controls, 1-year-old Western scrub jays (Aphelocoma californica) that experienced nutritional deficits during early posthatching development had smaller hippocampi with fewer neurons and performed worse in a cache recovery task and in a spatial version of an associative learning task. In contrast, performance of nutritionally deprived birds was similar to that of controls in 2 color versions of an associative learning task. These findings suggest that nutritional deficits during early development have long-term consequences for hippocampal structure and spatial memory, which, in turn, are likely to have a strong impact on animals' future fitness.

  1. Memory-efficient dynamic programming backtrace and pairwise local sequence alignment.

    Science.gov (United States)

    Newberg, Lee A

    2008-08-15

    A backtrace through a dynamic programming algorithm's intermediate results in search of an optimal path, or to sample paths according to an implied probability distribution, or as the second stage of a forward-backward algorithm, is a task of fundamental importance in computational biology. When there is insufficient space to store all intermediate results in high-speed memory (e.g. cache) existing approaches store selected stages of the computation, and recompute missing values from these checkpoints on an as-needed basis. Here we present an optimal checkpointing strategy, and demonstrate its utility with pairwise local sequence alignment of sequences of length 10,000. Sample C++-code for optimal backtrace is available in the Supplementary Materials. Supplementary data is available at Bioinformatics online.

  2. Visual memory needs categories

    OpenAIRE

    Olsson, Henrik; Poom, Leo

    2005-01-01

    Capacity limitations in the way humans store and process information in working memory have been extensively studied, and several memory systems have been distinguished. In line with previous capacity estimates for verbal memory and memory for spatial information, recent studies suggest that it is possible to retain up to four objects in visual working memory. The objects used have typically been categorically different colors and shapes. Because knowledge about categories is stored in long-t...

  3. Non-volatile memories

    CERN Document Server

    Lacaze, Pierre-Camille

    2014-01-01

    Written for scientists, researchers, and engineers, Non-volatile Memories describes the recent research and implementations in relation to the design of a new generation of non-volatile electronic memories. The objective is to replace existing memories (DRAM, SRAM, EEPROM, Flash, etc.) with a universal memory model likely to reach better performances than the current types of memory: extremely high commutation speeds, high implantation densities and retention time of information of about ten years.

  4. Memory: sins and virtues

    OpenAIRE

    Schacter, Daniel L.

    2013-01-01

    Memory plays an important role in everyday life but does not provide an exact and unchanging record of experience: research has documented that memory is a constructive process that is subject to a variety of errors and distortions. Yet these memory “sins” also reflect the operation of adaptive aspects of memory. Memory can thus be characterized as an adaptive constructive process, which plays a functional role in cognition but produces distortions, errors, or illusions as a consequence of d...

  5. A Yeast Purification System for Human Translation Initiation Factors eIF2 and eIF2B epsilon and Their Use in the Diagnosis of CACH/VWM Disease

    NARCIS (Netherlands)

    de Almeida, R.A.; Fogli, A.; Gaillard, M.; Scheper, G.C.; Boesflug-Tanguy, O.; Pavitt, G.D.

    2013-01-01

    Recessive inherited mutations in any of five subunits of the general protein synthesis factor eIF2B are responsible for a white mater neurodegenerative disease with a large clinical spectrum. The classical form is called Childhood Ataxia with CNS hypomyelination (CACH) or Vanishing White Matter

  6. Salam Memorial

    CERN Document Server

    Rubbia, Carlo

    1997-01-01

    by T.W.B. KIBBLE / Blackett Laboratory, Imperial College, London. Recollections of Abdus Salam at Imperial College I shall give a personal account of Professor Salam's life and work from the perspective of a colleague at Imperial College, concentrating particularly but not exclusively on the period leading up to the discovery of the electro-weak theory. If necessary I could perhaps give more detail, but only once I have given more thought to what ground I shall cover. by Sheldon Lee GLASHOW / Harvard University, Cambridge, MA, USA. Memories of Abdus Salam. My interactions with Abdus Salam, weak as they have been, extended over five decades. I regret that we never once collaborated in print or by correspondence. I visited Abdus only twice in London and twice again in Trieste, and met him at the occasional conference or summer school. Our face-to-face encounters could be counted on one's fingers and toes, but we became the best of friends. Others will discuss Abdus as an inspiring teacher, as a great scientist,...

  7. Organizational memory: from expectations memory to procedural memory

    NARCIS (Netherlands)

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

    2009-01-01

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

  8. Visual Memories Bypass Normalization.

    Science.gov (United States)

    Bloem, Ilona M; Watanabe, Yurika L; Kibbe, Melissa M; Ling, Sam

    2018-05-01

    How distinct are visual memory representations from visual perception? Although evidence suggests that briefly remembered stimuli are represented within early visual cortices, the degree to which these memory traces resemble true visual representations remains something of a mystery. Here, we tested whether both visual memory and perception succumb to a seemingly ubiquitous neural computation: normalization. Observers were asked to remember the contrast of visual stimuli, which were pitted against each other to promote normalization either in perception or in visual memory. Our results revealed robust normalization between visual representations in perception, yet no signature of normalization occurring between working memory stores-neither between representations in memory nor between memory representations and visual inputs. These results provide unique insight into the nature of visual memory representations, illustrating that visual memory representations follow a different set of computational rules, bypassing normalization, a canonical visual computation.

  9. Stochastic memory: getting memory out of noise

    Science.gov (United States)

    Stotland, Alexander; di Ventra, Massimiliano

    2011-03-01

    Memory circuit elements, namely memristors, memcapacitors and meminductors, can store information without the need of a power source. These systems are generally defined in terms of deterministic equations of motion for the state variables that are responsible for memory. However, in real systems noise sources can never be eliminated completely. One would then expect noise to be detrimental for memory. Here, we show that under specific conditions on the noise intensity memory can actually be enhanced. We illustrate this phenomenon using a physical model of a memristor in which the addition of white noise into the state variable equation improves the memory and helps the operation of the system. We discuss under which conditions this effect can be realized experimentally, discuss its implications on existing memory systems discussed in the literature, and also analyze the effects of colored noise. Work supported in part by NSF.

  10. Detailed Sensory Memory, Sloppy Working Memory

    OpenAIRE

    Sligte, Ilja G.; Vandenbroucke, Annelinde R. E.; Scholte, H. Steven; Lamme, Victor A. F.

    2010-01-01

    Visual short-term memory (VSTM) enables us to actively maintain information in mind for a brief period of time after stimulus disappearance. According to recent studies, VSTM consists of three stages - iconic memory, fragile VSTM, and visual working memory - with increasingly stricter capacity limits and progressively longer lifetimes. Still, the resolution (or amount of visual detail) of each VSTM stage has remained unexplored and we test this in the present study. We presented people with a...

  11. Detailed sensory memory, sloppy working memory.

    Science.gov (United States)

    Sligte, Ilja G; Vandenbroucke, Annelinde R E; Scholte, H Steven; Lamme, Victor A F

    2010-01-01

    Visual short-term memory (VSTM) enables us to actively maintain information in mind for a brief period of time after stimulus disappearance. According to recent studies, VSTM consists of three stages - iconic memory, fragile VSTM, and visual working memory - with increasingly stricter capacity limits and progressively longer lifetimes. Still, the resolution (or amount of visual detail) of each VSTM stage has remained unexplored and we test this in the present study. We presented people with a change detection task that measures the capacity of all three forms of VSTM, and we added an identification display after each change trial that required people to identify the "pre-change" object. Accurate change detection plus pre-change identification requires subjects to have a high-resolution representation of the "pre-change" object, whereas change detection or identification only can be based on the hunch that something has changed, without exactly knowing what was presented before. We observed that people maintained 6.1 objects in iconic memory, 4.6 objects in fragile VSTM, and 2.1 objects in visual working memory. Moreover, when people detected the change, they could also identify the pre-change object on 88% of the iconic memory trials, on 71% of the fragile VSTM trials and merely on 53% of the visual working memory trials. This suggests that people maintain many high-resolution representations in iconic memory and fragile VSTM, but only one high-resolution object representation in visual working memory.

  12. La face cachée de l’ancestralité. Masques et affinité chez les Matis d’Amazonie brésilienne

    OpenAIRE

    Erikson, Philippe

    2009-01-01

    La face cachée de l’ancestralité. Masques et affinité chez les Matis d’Amazonie brésilienne. Cet article montre en quoi les masques matis sont révélateurs des conceptions ouest amazoniennes de la temporalité et de la succession des générations. Après une discussion sur l’aspect cérémoniel des mascarades et sur les caractéristiques ontologiques imputées aux esprits mariwin, ce texte soutient que ces derniers, bien qu’associés aux morts du groupe et à des valeurs endogènes, représentent des aff...

  13. Prospective memory, working memory, retrospective memory and self-rated memory performance in persons with intellectual disability

    OpenAIRE

    Levén, Anna; Lyxell, Björn; Andersson, Jan; Danielsson, Henrik; Rönnberg, Jerker

    2008-01-01

    The purpose of the present study was to examine the relationship between prospective memory, working memory, retrospective memory and self-rated memory capacity in adults with and without intellectual disability. Prospective memory was investigated by means of a picture-based task. Working memory was measured as performance on span tasks. Retrospective memory was scored as recall of subject performed tasks. Self-ratings of memory performance were based on the prospective and retrospective mem...

  14. Main Memory DBMS

    NARCIS (Netherlands)

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

    2008-01-01

    htmlabstractA main memory database system is a DBMS that primarily relies on main memory for computer data storage. In contrast, normal database management systems employ hard disk based persisntent storage.

  15. Coping with Memory Loss

    Science.gov (United States)

    ... Consumers Home For Consumers Consumer Updates Coping With Memory Loss Share Tweet Linkedin Pin it More sharing ... be evaluated by a health professional. What Causes Memory Loss? Anything that affects cognition—the process of ...

  16. Memory and Aging

    Science.gov (United States)

    Memory and Aging Losing keys, misplacing a wallet, or forgetting someone’s name are common experiences. But for people nearing or over age 65, such memory lapses can be frightening. They wonder if they ...

  17. Tracing Cultural Memory

    DEFF Research Database (Denmark)

    Wiegand, Frauke Katharina

    by their encounters – to address a question that thirty years of ground - breaking research into memory has not yet sufficiently answered: What can we learn about the dynamics of cultural memory by examining mundane accounts of touristic encounters with sites of memory? From Blaavand Beach in Western Denmark......We encounter, relate to and make use of our past and that of others in multifarious and increasingly mobile ways. Tourism is one of the main paths for encountering sites of memory. This thesis examines tourists’ creative appropriations of sites of memory – the objects and future memories inspired...... of memory. They highlight the role of mundane uses of the past and indicate the need for cross - disciplinary research on the visual and on memory...

  18. Emotional Memory Persists Longer than Event Memory

    Science.gov (United States)

    Kuriyama, Kenichi; Soshi, Takahiro; Fujii, Takeshi; Kim, Yoshiharu

    2010-01-01

    The interaction between amygdala-driven and hippocampus-driven activities is expected to explain why emotion enhances episodic memory recognition. However, overwhelming behavioral evidence regarding the emotion-induced enhancement of immediate and delayed episodic memory recognition has not been obtained in humans. We found that the recognition…

  19. Notified Access: Extending Remote Memory Access Programming Models for Producer-Consumer Synchronization

    KAUST Repository

    Belli, Roberto; Hoefler, Torsten

    2015-01-01

    Remote Memory Access (RMA) programming enables direct access to low-level hardware features to achieve high performance for distributed-memory programs. However, the design of RMA programming schemes focuses on the memory access and less on the synchronization. For example, in contemporary RMA programming systems, the widely used producer-consumer pattern can only be implemented inefficiently, incurring in an overhead of an additional round-trip message. We propose Notified Access, a scheme where the target process of an access can receive a completion notification. This scheme enables direct and efficient synchronization with a minimum number of messages. We implement our scheme in an open source MPI-3 RMA library and demonstrate lower overheads (two cache misses) than other point-to-point synchronization mechanisms for each notification. We also evaluate our implementation on three real-world benchmarks, a stencil computation, a tree computation, and a Colicky factorization implemented with tasks. Our scheme always performs better than traditional message passing and other existing RMA synchronization schemes, providing up to 50% speedup on small messages. Our analysis shows that Notified Access is a valuable primitive for any RMA system. Furthermore, we provide guidance for the design of low-level network interfaces to support Notified Access efficiently.

  20. Notified Access: Extending Remote Memory Access Programming Models for Producer-Consumer Synchronization

    KAUST Repository

    Belli, Roberto

    2015-05-01

    Remote Memory Access (RMA) programming enables direct access to low-level hardware features to achieve high performance for distributed-memory programs. However, the design of RMA programming schemes focuses on the memory access and less on the synchronization. For example, in contemporary RMA programming systems, the widely used producer-consumer pattern can only be implemented inefficiently, incurring in an overhead of an additional round-trip message. We propose Notified Access, a scheme where the target process of an access can receive a completion notification. This scheme enables direct and efficient synchronization with a minimum number of messages. We implement our scheme in an open source MPI-3 RMA library and demonstrate lower overheads (two cache misses) than other point-to-point synchronization mechanisms for each notification. We also evaluate our implementation on three real-world benchmarks, a stencil computation, a tree computation, and a Colicky factorization implemented with tasks. Our scheme always performs better than traditional message passing and other existing RMA synchronization schemes, providing up to 50% speedup on small messages. Our analysis shows that Notified Access is a valuable primitive for any RMA system. Furthermore, we provide guidance for the design of low-level network interfaces to support Notified Access efficiently.

  1. Music, memory and emotion

    Science.gov (United States)

    Jäncke, Lutz

    2008-01-01

    Because emotions enhance memory processes and music evokes strong emotions, music could be involved in forming memories, either about pieces of music or about episodes and information associated with particular music. A recent study in BMC Neuroscience has given new insights into the role of emotion in musical memory. PMID:18710596

  2. Attending to auditory memory.

    Science.gov (United States)

    Zimmermann, Jacqueline F; Moscovitch, Morris; Alain, Claude

    2016-06-01

    Attention to memory describes the process of attending to memory traces when the object is no longer present. It has been studied primarily for representations of visual stimuli with only few studies examining attention to sound object representations in short-term memory. Here, we review the interplay of attention and auditory memory with an emphasis on 1) attending to auditory memory in the absence of related external stimuli (i.e., reflective attention) and 2) effects of existing memory on guiding attention. Attention to auditory memory is discussed in the context of change deafness, and we argue that failures to detect changes in our auditory environments are most likely the result of a faulty comparison system of incoming and stored information. Also, objects are the primary building blocks of auditory attention, but attention can also be directed to individual features (e.g., pitch). We review short-term and long-term memory guided modulation of attention based on characteristic features, location, and/or semantic properties of auditory objects, and propose that auditory attention to memory pathways emerge after sensory memory. A neural model for auditory attention to memory is developed, which comprises two separate pathways in the parietal cortex, one involved in attention to higher-order features and the other involved in attention to sensory information. This article is part of a Special Issue entitled SI: Auditory working memory. Copyright © 2015 Elsevier B.V. All rights reserved.

  3. Saving Malta's music memory

    OpenAIRE

    Sant, Toni

    2013-01-01

    Maltese music is being lost. Along with it Malta loses its culture, way of life, and memories. Dr Toni Sant is trying to change this trend through the Malta Music Memory Project (M3P) http://www.um.edu.mt/think/saving-maltas-music-memory-2/

  4. Associative Memory Acceptors.

    Science.gov (United States)

    Card, Roger

    The properties of an associative memory are examined in this paper from the viewpoint of automata theory. A device called an associative memory acceptor is studied under real-time operation. The family "L" of languages accepted by real-time associative memory acceptors is shown to properly contain the family of languages accepted by one-tape,…

  5. Generation and Context Memory

    Science.gov (United States)

    Mulligan, Neil W.; Lozito, Jeffrey P.; Rosner, Zachary A.

    2006-01-01

    Generation enhances memory for occurrence but may not enhance other aspects of memory. The present study further delineates the negative generation effect in context memory reported in N. W. Mulligan (2004). First, the negative generation effect occurred for perceptual attributes of the target item (its color and font) but not for extratarget…

  6. Music, memory and emotion.

    Science.gov (United States)

    Jäncke, Lutz

    2008-08-08

    Because emotions enhance memory processes and music evokes strong emotions, music could be involved in forming memories, either about pieces of music or about episodes and information associated with particular music. A recent study in BMC Neuroscience has given new insights into the role of emotion in musical memory.

  7. ECT and memory loss.

    Science.gov (United States)

    Squire, L R

    1977-09-01

    The author reviews several studies that clarify the nature of the memory loss associated with ECT. Bilateral ECT produced greater anterograde memory loss than right unilateral ECT and more extensive retrograde amnesia than unilateral ECT. Reactivating memories just before ECT did not produce amnesia. Capacity for new learning recovered substantially by several months after ECT, but memory complaints were common in individuals who had received bilateral ECT. Other things being equal, right unilateral ECT seems preferable to bilateral ECT because the risks to memory associated with unilateral ECT are smaller.

  8. Determination of memory performance

    International Nuclear Information System (INIS)

    Gopych, P.M.

    1999-01-01

    Within the scope of testing statistical hypotheses theory a model definition and a computer method for model calculation of widely used in neuropsychology human memory performance (free recall, cued recall, and recognition probabilities), a model definition and a computer method for model calculation of intensities of cues used in experiments for testing human memory quality are proposed. Models for active and passive traces of memory and their relations are found. It was shown that autoassociative memory unit in the form of short two-layer artificial neural network with (or without) damages can be used for model description of memory performance in subjects with (or without) local brain lesions

  9. Quantum random access memory

    OpenAIRE

    Giovannetti, Vittorio; Lloyd, Seth; Maccone, Lorenzo

    2007-01-01

    A random access memory (RAM) uses n bits to randomly address N=2^n distinct memory cells. A quantum random access memory (qRAM) uses n qubits to address any quantum superposition of N memory cells. We present an architecture that exponentially reduces the requirements for a memory call: O(log N) switches need be thrown instead of the N used in conventional (classical or quantum) RAM designs. This yields a more robust qRAM algorithm, as it in general requires entanglement among exponentially l...

  10. Memory dynamics under stress.

    Science.gov (United States)

    Quaedflieg, Conny W E M; Schwabe, Lars

    2018-03-01

    Stressful events have a major impact on memory. They modulate memory formation in a time-dependent manner, closely linked to the temporal profile of action of major stress mediators, in particular catecholamines and glucocorticoids. Shortly after stressor onset, rapidly acting catecholamines and fast, non-genomic glucocorticoid actions direct cognitive resources to the processing and consolidation of the ongoing threat. In parallel, control of memory is biased towards rather rigid systems, promoting habitual forms of memory allowing efficient processing under stress, at the expense of "cognitive" systems supporting memory flexibility and specificity. In this review, we discuss the implications of this shift in the balance of multiple memory systems for the dynamics of the memory trace. Specifically, stress appears to hinder the incorporation of contextual details into the memory trace, to impede the integration of new information into existing knowledge structures, to impair the flexible generalisation across past experiences, and to hamper the modification of memories in light of new information. Delayed, genomic glucocorticoid actions might reverse the control of memory, thus restoring homeostasis and "cognitive" control of memory again.

  11. Detailed sensory memory, sloppy working memory

    Directory of Open Access Journals (Sweden)

    Ilja G Sligte

    2010-10-01

    Full Text Available Visual short-term memory (VSTM enables us to actively maintain information in mind for a brief period of time after stimulus disappearance. According to recent studies, VSTM consists of three stages - iconic memory, fragile VSTM, and visual working memory - with increasingly stricter capacity limits and progressively longer lifetimes. Still, the resolution (or amount of visual detail of each VSTM stage has remained unexplored and we test this in the present study. We presented people with a change detection task that measures the capacity of all three forms of VSTM, and we added an identification display after each change trial that required people to identify the pre-change object. Accurate change detection plus pre-change identification requires subjects to have a high-resolution representation of the pre-change object, whereas change detection or identification only can be based on the hunch that something has changed, without exactly knowing what was presented before. We observed that people maintained 6.1 objects in iconic memory, 4.6 objects in fragile VSTM and 2.1 objects in visual working memory. Moreover, when people detected the change, they could also identify the pre-change object on 88 percent of the iconic memory trials, on 71 percent of the fragile VSTM trials and merely on 53 percent of the visual working memory trials. This suggests that people maintain many high-resolution representations in iconic memory and fragile VSTM, but only one high-resolution object representation in visual working memory.

  12. NAND flash memory technologies

    CERN Document Server

    Aritome, Seiichi

    2016-01-01

    This book discusses basic and advanced NAND flash memory technologies, including the principle of NAND flash, memory cell technologies, multi-bits cell technologies, scaling challenges of memory cell, reliability, and 3-dimensional cell as the future technology. Chapter 1 describes the background and early history of NAND flash. The basic device structures and operations are described in Chapter 2. Next, the author discusses the memory cell technologies focused on scaling in Chapter 3, and introduces the advanced operations for multi-level cells in Chapter 4. The physical limitations for scaling are examined in Chapter 5, and Chapter 6 describes the reliability of NAND flash memory. Chapter 7 examines 3-dimensional (3D) NAND flash memory cells and discusses the pros and cons in structure, process, operations, scalability, and performance. In Chapter 8, challenges of 3D NAND flash memory are dis ussed. Finally, in Chapter 9, the author summarizes and describes the prospect of technologies and market for the fu...

  13. Stochastic memory: Memory enhancement due to noise

    Science.gov (United States)

    Stotland, Alexander; di Ventra, Massimiliano

    2012-01-01

    There are certain classes of resistors, capacitors, and inductors that, when subject to a periodic input of appropriate frequency, develop hysteresis loops in their characteristic response. Here we show that the hysteresis of such memory elements can also be induced by white noise of appropriate intensity even at very low frequencies of the external driving field. We illustrate this phenomenon using a physical model of memory resistor realized by TiO2 thin films sandwiched between metallic electrodes and discuss under which conditions this effect can be observed experimentally. We also discuss its implications on existing memory systems described in the literature and the role of colored noise.

  14. An integrated GIS/remote sensing data base in North Cache soil conservation district, Utah: A pilot project for the Utah Department of Agriculture's RIMS (Resource Inventory and Monitoring System)

    Science.gov (United States)

    Wheeler, D. J.; Ridd, M. K.; Merola, J. A.

    1984-01-01

    A basic geographic information system (GIS) for the North Cache Soil Conservation District (SCD) was sought for selected resource problems. Since the resource management issues in the North Cache SCD are very complex, it is not feasible in the initial phase to generate all the physical, socioeconomic, and political baseline data needed for resolving all management issues. A selection of critical varables becomes essential. Thus, there are foud specific objectives: (1) assess resource management needs and determine which resource factors ae most fundamental for building a beginning data base; (2) evaluate the variety of data gathering and analysis techniques for the resource factors selected; (3) incorporate the resulting data into a useful and efficient digital data base; and (4) demonstrate the application of the data base to selected real world resoource management issues.

  15. The contributions of handedness and working memory to episodic memory.

    Science.gov (United States)

    Sahu, Aparna; Christman, Stephen D; Propper, Ruth E

    2016-11-01

    Past studies have independently shown associations of working memory and degree of handedness with episodic memory retrieval. The current study takes a step ahead by examining whether handedness and working memory independently predict episodic memory. In agreement with past studies, there was an inconsistent-handed advantage for episodic memory; however, this advantage was absent for working memory tasks. Furthermore, regression analyses showed handedness, and complex working memory predicted episodic memory performance at different times. Results are discussed in light of theories of episodic memory and hemispheric interaction.

  16. Memory for speech and speech for memory.

    Science.gov (United States)

    Locke, J L; Kutz, K J

    1975-03-01

    Thirty kindergarteners, 15 who substituted /w/ for /r/ and 15 with correct articulation, received two perception tests and a memory test that included /w/ and /r/ in minimally contrastive syllables. Although both groups had nearly perfect perception of the experimenter's productions of /w/ and /r/, misarticulating subjects perceived their own tape-recorded w/r productions as /w/. In the memory task these same misarticulating subjects committed significantly more /w/-/r/ confusions in unspoken recall. The discussion considers why people subvocally rehearse; a developmental period in which children do not rehearse; ways subvocalization may aid recall, including motor and acoustic encoding; an echoic store that provides additional recall support if subjects rehearse vocally, and perception of self- and other- produced phonemes by misarticulating children-including its relevance to a motor theory of perception. Evidence is presented that speech for memory can be sufficiently impaired to cause memory disorder. Conceptions that restrict speech disorder to an impairment of communication are challenged.

  17. Psychophysiology of prospective memory.

    Science.gov (United States)

    Rothen, Nicolas; Meier, Beat

    2014-01-01

    Prospective memory involves the self-initiated retrieval of an intention upon an appropriate retrieval cue. Cue identification can be considered as an orienting reaction and may thus trigger a psychophysiological response. Here we present two experiments in which skin conductance responses (SCRs) elicited by prospective memory cues were compared to SCRs elicited by aversive stimuli to test whether a single prospective memory cue triggers a similar SCR as an aversive stimulus. In Experiment 2 we also assessed whether cue specificity had a differential influence on prospective memory performance and on SCRs. We found that detecting a single prospective memory cue is as likely to elicit a SCR as an aversive stimulus. Missed prospective memory cues also elicited SCRs. On a behavioural level, specific intentions led to better prospective memory performance. However, on a psychophysiological level specificity had no influence. More generally, the results indicate reliable SCRs for prospective memory cues and point to psychophysiological measures as valuable approach, which offers a new way to study one-off prospective memory tasks. Moreover, the findings are consistent with a theory that posits multiple prospective memory retrieval stages.

  18. Intentionally fabricated autobiographical memories.

    Science.gov (United States)

    Justice, Lucy V; Morrison, Catriona M; Conway, Martin A

    2018-02-01

    Participants generated both autobiographical memories (AMs) that they believed to be true and intentionally fabricated autobiographical memories (IFAMs). Memories were constructed while a concurrent memory load (random 8-digit sequence) was held in mind or while there was no concurrent load. Amount and accuracy of recall of the concurrent memory load was reliably poorer following generation of IFAMs than following generation of AMs. There was no reliable effect of load on memory generation times; however, IFAMs always took longer to construct than AMs. Finally, replicating previous findings, fewer IFAMs had a field perspective than AMs, IFAMs were less vivid than AMs, and IFAMs contained more motion words (indicative of increased cognitive load). Taken together, these findings show a pattern of systematic differences that mark out IFAMs, and they also show that IFAMs can be identified indirectly by lowered performance on concurrent tasks that increase cognitive load.

  19. Shape memory polymers

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Thomas S.; Bearinger, Jane P.

    2017-08-29

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  20. Time for memory

    DEFF Research Database (Denmark)

    Murakami, Kyoko

    2012-01-01

    This article is a continuous dialogue on memory triggered by Brockmeier’s (2010) article. I drift away from the conventionalization of the archive as a spatial metaphor for memory in order to consider the greater possibility of “time” for conceptualizing memory. The concept of time is central...... in terms of autobiographical memory. The second category of time is discussed, drawing on Augustine and Bergson amongst others. Bergson’s notion of duration has been considered as a promising concept for a better understanding of autobiographical memory. Psychological phenomena such as autobiographical...... memory should embrace not only spatial dimension, but also a temporal dimension, in which a constant flow of irreversible time, where multiplicity, momentarily, dynamic stability and becoming and emergence of novelty can be observed....