WorldWideScience

Sample records for instruction cache scheme

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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...

  7. 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 ...

  8. 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...

  9. 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....

  10. 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...

  11. 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.

  12. 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.

  13. 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...

  14. 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.

  15. 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.

  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. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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...

  5. 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.

  6. 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.

  7. 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...

  8. 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.

  9. 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...

  10. 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...

  11. 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.

  12. 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...

  13. 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.

  14. 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.

  15. 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.

  16. 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

  17. 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....

  18. 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.

  19. 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

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. 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

  5. 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.

  6. 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...

  7. 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....

  8. 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...

  9. 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

  10. 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.

  11. 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.

  12. 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...

  13. 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...

  14. 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...

  15. 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.

  16. 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...

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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)

  2. 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.

  3. 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...

  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. 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...

  6. 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)....

  7. 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.

  8. 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.

  9. 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...

  10. 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.

  11. 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...

  12. 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...

  13. 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...

  14. 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

  15. 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.

  16. 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.

  17. 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...

  18. 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

  19. 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...

  20. Instant effective caching with Ehcache

    CERN Document Server

    Wind, Daniel

    2013-01-01

    Filled with practical, step-by-step instructions and clear explanations for the most important and useful tasks. This is a Packt How-to containing hands-on recipes that discuss integrating Ehcache into your Java application.This book is aimed at Java developers who are looking for an Ehcache integration reference guide and want to get a good background in its fundamental core functionality. It is assumed that you have some experience with Java. Prior knowledge in Ehcache is not a requirement.

  1. 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.

  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. 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...

  4. 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.

  5. 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...

  6. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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...

  11. 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

  12. 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.

  13. 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.

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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...

  1. 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...

  2. 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.

  3. 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

  4. 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...

  5. 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.

  6. 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...

  7. 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.

  8. 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.

  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. 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.

  11. 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.

  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. 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. 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. 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...

  17. 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....

  18. 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)....

  19. 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.

  20. 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

  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. 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...

  3. AN AGENT BASED TRANSACTION PROCESSING SCHEME FOR DISCONNECTED MOBILE NODES

    Directory of Open Access Journals (Sweden)

    J.L. Walter Jeyakumar

    2010-12-01

    Full Text Available We present a mobile transaction framework in which mobile users can share data which is stored in the cache of a mobile agent. This mobile agent is a special mobile node which coordinates the sharing process. The proposed framework allows mobile affiliation work groups to be formed dynamically with a mobile agent and mobile hosts. Using short range wireless communication technology, mobile users can simultaneously access the data from the cache of the mobile agent. The data Access Manager module at the mobile agent enforces concurrency control using cache invalidation technique. This model supports disconnected mobile computing allowing mobile agent to move along with the Mobile Hosts. The proposed Transaction frame work has been simulated in Java 2 and performance of this scheme is compared with existing frame works.

  4. 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.

  5. 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

  6. 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...

  7. 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...

  8. 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...

  9. 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

  10. 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.

  11. 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...

  12. 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...

  13. 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...

  14. 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...

  15. 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...

  16. 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

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.)

  2. 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.

  3. 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.

  4. 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.

  5. 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

  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. 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 ...

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. 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.

  17. 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

  18. 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 ...

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. D2D-Enabled Small Cell Network Control Scheme Based on the Dynamic Stackelberg Game

    Directory of Open Access Journals (Sweden)

    Sungwook Kim

    2017-01-01

    Full Text Available For current and future cellular networks, small cell structure with licensed and unlicensed bandwidth, caching content provisioning, and device-to-device (D2D communications is seen as a necessary architecture. Recently, a series of control methods have been developed to address a myriad of challenges in next-generation small cell networks. In this study, we focus on the design of novel D2D-enabled small cell network control scheme by allowing caching and unlicensed D2D communications. Motivated by game theory and learning algorithm, the proposed scheme adaptively selects caching contents and splits the available bandwidth for licensed and unlicensed communications. Under dynamically changing network environments, we capture the dynamics of the network system and design a new dynamic Stackelberg game model. Based on a hierarchical and feedback based control manner, small base stations and users can be leaders or followers dynamically while improving 5G network performance. Simulations and performance analysis verify the efficiency of the proposed scheme, showing that our approach can outperform existing schemes by about 5%~15% in terms of bandwidth utilization, cache hit ratio, and system throughput.

  5. 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).

  6. 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...

  7. 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....

  8. 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

  9. 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...

  10. 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...

  11. 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)

  12. 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.

  13. 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...

  14. 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

  15. 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.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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...

  1. A virtual network computer's optical storage virtualization scheme

    Science.gov (United States)

    Wang, Jianzong; Hu, Huaixiang; Wan, Jiguang; Wang, Peng

    2008-12-01

    In this paper, we present the architecture and implementation of a virtual network computers' (VNC) optical storage virtualization scheme called VOSV. Its task is to manage the mapping of virtual optical storage to physical optical storage, a technique known as optical storage virtualization. The design of VOSV aims at the optical storage resources of different clients and servers that have high read-sharing patterns. VOSV uses several schemes such as a two-level Cache mechanism, a VNC server embedded module and the iSCSI protocols to improve the performance. The results measured on the prototype are encouraging, and indicating that VOSV provides the high I/O performance.

  2. Colour schemes

    DEFF Research Database (Denmark)

    van Leeuwen, Theo

    2013-01-01

    This chapter presents a framework for analysing colour schemes based on a parametric approach that includes not only hue, value and saturation, but also purity, transparency, luminosity, luminescence, lustre, modulation and differentiation.......This chapter presents a framework for analysing colour schemes based on a parametric approach that includes not only hue, value and saturation, but also purity, transparency, luminosity, luminescence, lustre, modulation and differentiation....

  3. N-body simulation for self-gravitating collisional systems with a new SIMD instruction set extension to the x86 architecture, Advanced Vector eXtensions

    Science.gov (United States)

    Tanikawa, Ataru; Yoshikawa, Kohji; Okamoto, Takashi; Nitadori, Keigo

    2012-02-01

    We present a high-performance N-body code for self-gravitating collisional systems accelerated with the aid of a new SIMD instruction set extension of the x86 architecture: Advanced Vector eXtensions (AVX), an enhanced version of the Streaming SIMD Extensions (SSE). With one processor core of Intel Core i7-2600 processor (8 MB cache and 3.40 GHz) based on Sandy Bridge micro-architecture, we implemented a fourth-order Hermite scheme with individual timestep scheme ( Makino and Aarseth, 1992), and achieved the performance of ˜20 giga floating point number operations per second (GFLOPS) for double-precision accuracy, which is two times and five times higher than that of the previously developed code implemented with the SSE instructions ( Nitadori et al., 2006b), and that of a code implemented without any explicit use of SIMD instructions with the same processor core, respectively. We have parallelized the code by using so-called NINJA scheme ( Nitadori et al., 2006a), and achieved ˜90 GFLOPS for a system containing more than N = 8192 particles with 8 MPI processes on four cores. We expect to achieve about 10 tera FLOPS (TFLOPS) for a self-gravitating collisional system with N ˜ 10 5 on massively parallel systems with at most 800 cores with Sandy Bridge micro-architecture. This performance will be comparable to that of Graphic Processing Unit (GPU) cluster systems, such as the one with about 200 Tesla C1070 GPUs ( Spurzem et al., 2010). This paper offers an alternative to collisional N-body simulations with GRAPEs and GPUs.

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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...

  10. 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...

  11. 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.

  12. 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...

  13. 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.

  14. 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...

  15. A concept model for learning: An attempt to define a proper relations scheme between instruction, learning and to establish the dynamics of learning in relation to modern political concepts as study-fairness.

    NARCIS (Netherlands)

    Min, F.B.M.; Vos, Henk; Kommers, Petrus A.M.; van Dijkum, C.; van Dijkum, C.

    2000-01-01

    For years, it has been attempted within educational science to establish the process of learning. A lot is known about instruction, but as to learning and acquiring knowledge and insight, we still know very little. A lot of research is conducted on methods of instruction, but very little on learning

  16. Tradable schemes

    NARCIS (Netherlands)

    J.K. Hoogland (Jiri); C.D.D. Neumann

    2000-01-01

    textabstractIn this article we present a new approach to the numerical valuation of derivative securities. The method is based on our previous work where we formulated the theory of pricing in terms of tradables. The basic idea is to fit a finite difference scheme to exact solutions of the pricing

  17. 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.

  18. 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.

  19. 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.

  20. 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...

  1. 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.

  2. 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.

  3. 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.

  4. 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...

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. 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....

  12. 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...

  13. 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.

  14. 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.

  15. Additive operator-difference schemes splitting schemes

    CERN Document Server

    Vabishchevich, Petr N

    2013-01-01

    Applied mathematical modeling isconcerned with solving unsteady problems. This bookshows how toconstruct additive difference schemes to solve approximately unsteady multi-dimensional problems for PDEs. Two classes of schemes are highlighted: methods of splitting with respect to spatial variables (alternating direction methods) and schemes of splitting into physical processes. Also regionally additive schemes (domain decomposition methods)and unconditionally stable additive schemes of multi-component splitting are considered for evolutionary equations of first and second order as well as for sy

  16. 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...

  17. 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...

  18. 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....

  19. 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.

  20. 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.

  1. 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.

  2. A Probabilistic Analysis of Data Popularity in ATLAS Data Caching

    International Nuclear Information System (INIS)

    Titov, M; Záruba, G; De, K; Klimentov, A

    2012-01-01

    One of the most important aspects in any computing distribution system is efficient data replication over storage or computing centers, that guarantees high data availability and low cost for resource utilization. In this paper we propose a data distribution scheme for the production and distributed analysis system PanDA at the ATLAS experiment. Our proposed scheme is based on the investigation of data usage. Thus, the paper is focused on the main concepts of data popularity in the PanDA system and their utilization. Data popularity is represented as the set of parameters that are used to predict the future data state in terms of popularity levels.

  3. 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.

  4. 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.

  5. 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

  6. 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

  7. 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

  8. 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

  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. 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

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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...

  16. 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

  17. 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,

  18. 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.

  19. Lightweight SIP/SDP compression scheme (LSSCS)

    Science.gov (United States)

    Wu, Jian J.; Demetrescu, Cristian

    2001-10-01

    In UMTS new IP based services with tight delay constraints will be deployed over the W-CDMA air interface such as IP multimedia and interactive services. To integrate the wireline and wireless IP services, 3GPP standard forum adopted the Session Initiation Protocol (SIP) as the call control protocol for the UMTS Release 5, which will implement next generation, all IP networks for real-time QoS services. In the current form the SIP protocol is not suitable for wireless transmission due to its large message size which will need either a big radio pipe for transmission or it will take far much longer to transmit than the current GSM Call Control (CC) message sequence. In this paper we present a novel compression algorithm called Lightweight SIP/SDP Compression Scheme (LSSCS), which acts at the SIP application layer and therefore removes the information redundancy before it is sent to the network and transport layer. A binary octet-aligned header is added to the compressed SIP/SDP message before sending it to the network layer. The receiver uses this binary header as well as the pre-cached information to regenerate the original SIP/SDP message. The key features of the LSSCS compression scheme are presented in this paper along with implementation examples. It is shown that this compression algorithm makes SIP transmission efficient over the radio interface without losing the SIP generality and flexibility.

  20. Editorial - Instructions

    DEFF Research Database (Denmark)

    Kastberg, Peter; Grinsted, Annelise

    2007-01-01

    Why you may wonder - have we chosen a topic which at first glance may seem trivial, and even a bit dull? Well, looks can be deceiving, and in this case they are! There are many good reasons for taking a closer look at instructions.......Why you may wonder - have we chosen a topic which at first glance may seem trivial, and even a bit dull? Well, looks can be deceiving, and in this case they are! There are many good reasons for taking a closer look at instructions....

  1. 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.

  2. 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),...

  3. 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.

  4. 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.

  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. 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.

  7. 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.

  8. 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.

  9. 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

  10. 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.

  11. 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.

  12. 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

  13. Instructional Partners, Principals, Teachers, and Instructional Assistants.

    Science.gov (United States)

    Indiana State Dept. of Public Instruction, Indianapolis.

    This handbook examines various topics of interest and concern to teachers as they work with instructional assistants forming a classroom instructional partnership and functioning as a team. These topics include: (1) instructional assistant qualifications; (2) duties--instructional, classroom clerical, auxillary; (3) factors to be considered when…

  14. Finite Boltzmann schemes

    NARCIS (Netherlands)

    Sman, van der R.G.M.

    2006-01-01

    In the special case of relaxation parameter = 1 lattice Boltzmann schemes for (convection) diffusion and fluid flow are equivalent to finite difference/volume (FD) schemes, and are thus coined finite Boltzmann (FB) schemes. We show that the equivalence is inherent to the homology of the

  15. Adaptive data migration scheme with facilitator database and multi-tier distributed storage in LHD

    International Nuclear Information System (INIS)

    Nakanishi, Hideya; Masaki, Ohsuna; Mamoru, Kojima; Setsuo, Imazu; Miki, Nonomura; Kenji, Watanabe; Masayoshi, Moriya; Yoshio, Nagayama; Kazuo, Kawahata

    2008-01-01

    Recent 'data explosion' induces the demand for high flexibility of storage extension and data migration. The data amount of LHD plasma diagnostics has grown 4.6 times bigger than that of three years before. Frequent migration or replication between plenty of distributed storage becomes mandatory, and thus increases the human operational costs. To reduce them computationally, a new adaptive migration scheme has been developed on LHD's multi-tier distributed storage. So-called the HSM (Hierarchical Storage Management) software usually adopts a low-level cache mechanism or simple watermarks for triggering the data stage-in and out between two storage devices. However, the new scheme can deal with a number of distributed storage by the facilitator database that manages the whole data locations with their access histories and retrieval priorities. Not only the inter-tier migration but also the intra-tier replication and moving are even manageable so that it can be a big help in extending or replacing storage equipment. The access history of each data object is also utilized to optimize the volume size of fast and costly RAID, in addition to a normal cache effect for frequently retrieved data. The new scheme has been verified its effectiveness so that LHD multi-tier distributed storage and other next-generation experiments can obtain such the flexible expandability

  16. Using Errors to Improve the Quality of Instructional Programs.

    Science.gov (United States)

    Anderson, Lorin W.; And Others

    Clinchy and Rosenthal's error classification scheme was applied to test results to determine its ability to differentiate the effectiveness of instruction in two elementary schools. Mathematics retention tests matching the instructional objectives of both schools were constructed to measure the understanding of arithmetic concepts and the ability…

  17. 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...

  18. Regulations and instructions for RA reactor operation

    International Nuclear Information System (INIS)

    1989-01-01

    This regulatory guide consists of following 4 chapters: Description of the RA reactor, organization scheme, regulations for performing experiments; Regulations for staff on duty; Instructions for operating the vacuum systems, heavy water and helium systems; and evacuation in case of accident [sr

  19. 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...

  20. 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 ...

  1. 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.

  2. Scheme Program Documentation Tools

    DEFF Research Database (Denmark)

    Nørmark, Kurt

    2004-01-01

    are separate and intended for different documentation purposes they are related to each other in several ways. Both tools are based on XML languages for tool setup and for documentation authoring. In addition, both tools rely on the LAML framework which---in a systematic way---makes an XML language available...... as named functions in Scheme. Finally, the Scheme Elucidator is able to integrate SchemeDoc resources as part of an internal documentation resource....

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Multiresolution signal decomposition schemes

    NARCIS (Netherlands)

    J. Goutsias (John); H.J.A.M. Heijmans (Henk)

    1998-01-01

    textabstract[PNA-R9810] Interest in multiresolution techniques for signal processing and analysis is increasing steadily. An important instance of such a technique is the so-called pyramid decomposition scheme. This report proposes a general axiomatic pyramid decomposition scheme for signal analysis

  8. Adaptive protection scheme

    Directory of Open Access Journals (Sweden)

    R. Sitharthan

    2016-09-01

    Full Text Available This paper aims at modelling an electronically coupled distributed energy resource with an adaptive protection scheme. The electronically coupled distributed energy resource is a microgrid framework formed by coupling the renewable energy source electronically. Further, the proposed adaptive protection scheme provides a suitable protection to the microgrid for various fault conditions irrespective of the operating mode of the microgrid: namely, grid connected mode and islanded mode. The outstanding aspect of the developed adaptive protection scheme is that it monitors the microgrid and instantly updates relay fault current according to the variations that occur in the system. The proposed adaptive protection scheme also employs auto reclosures, through which the proposed adaptive protection scheme recovers faster from the fault and thereby increases the consistency of the microgrid. The effectiveness of the proposed adaptive protection is studied through the time domain simulations carried out in the PSCAD⧹EMTDC software environment.

  9. Strategy Instruction in Mathematics.

    Science.gov (United States)

    Goldman, Susan R.

    1989-01-01

    Experiments in strategy instruction for mathematics have been conducted using three models (direct instruction, self-instruction, and guided learning) applied to the tasks of computation and word problem solving. Results have implications for effective strategy instruction for learning disabled students. It is recommended that strategy instruction…

  10. Successful application and research of modularized scheme of containment liner of CPR1000+ reactor building

    International Nuclear Information System (INIS)

    Lu Qinwu; Zhang Shuxia; Guo Junying

    2012-01-01

    Research of modularized scheme in design, special grid structure spreader, crane, and successful applied in Yangjiang NPP project 3 will instruct and promote modularized construction of containment liner in construction projects. (authors)

  11. 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.

  12. 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.

  13. Threshold Signature Schemes Application

    Directory of Open Access Journals (Sweden)

    Anastasiya Victorovna Beresneva

    2015-10-01

    Full Text Available This work is devoted to an investigation of threshold signature schemes. The systematization of the threshold signature schemes was done, cryptographic constructions based on interpolation Lagrange polynomial, elliptic curves and bilinear pairings were examined. Different methods of generation and verification of threshold signatures were explored, the availability of practical usage of threshold schemes in mobile agents, Internet banking and e-currency was shown. The topics of further investigation were given and it could reduce a level of counterfeit electronic documents signed by a group of users.

  14. 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.

  15. Content Analysis Coding Schemes for Online Asynchronous Discussion

    Science.gov (United States)

    Weltzer-Ward, Lisa

    2011-01-01

    Purpose: Researchers commonly utilize coding-based analysis of classroom asynchronous discussion contributions as part of studies of online learning and instruction. However, this analysis is inconsistent from study to study with over 50 coding schemes and procedures applied in the last eight years. The aim of this article is to provide a basis…

  16. CSR schemes in agribusiness

    DEFF Research Database (Denmark)

    Pötz, Katharina Anna; Haas, Rainer; Balzarova, Michaela

    2013-01-01

    of schemes that can be categorized on focus areas, scales, mechanisms, origins, types and commitment levels. Research limitations/implications – The findings contribute to conceptual and empirical research on existing models to compare and analyse CSR standards. Sampling technique and depth of analysis limit......Purpose – The rise of CSR followed a demand for CSR standards and guidelines. In a sector already characterized by a large number of standards, the authors seek to ask what CSR schemes apply to agribusiness, and how they can be systematically compared and analysed. Design....../methodology/approach – Following a deductive-inductive approach the authors develop a model to compare and analyse CSR schemes based on existing studies and on coding qualitative data on 216 CSR schemes. Findings – The authors confirm that CSR standards and guidelines have entered agribusiness and identify a complex landscape...

  17. Tabled Execution in Scheme

    Energy Technology Data Exchange (ETDEWEB)

    Willcock, J J; Lumsdaine, A; Quinlan, D J

    2008-08-19

    Tabled execution is a generalization of memorization developed by the logic programming community. It not only saves results from tabled predicates, but also stores the set of currently active calls to them; tabled execution can thus provide meaningful semantics for programs that seemingly contain infinite recursions with the same arguments. In logic programming, tabled execution is used for many purposes, both for improving the efficiency of programs, and making tasks simpler and more direct to express than with normal logic programs. However, tabled execution is only infrequently applied in mainstream functional languages such as Scheme. We demonstrate an elegant implementation of tabled execution in Scheme, using a mix of continuation-passing style and mutable data. We also show the use of tabled execution in Scheme for a problem in formal language and automata theory, demonstrating that tabled execution can be a valuable tool for Scheme users.

  18. Evaluating statistical cloud schemes

    OpenAIRE

    Grützun, Verena; Quaas, Johannes; Morcrette , Cyril J.; Ament, Felix

    2015-01-01

    Statistical cloud schemes with prognostic probability distribution functions have become more important in atmospheric modeling, especially since they are in principle scale adaptive and capture cloud physics in more detail. While in theory the schemes have a great potential, their accuracy is still questionable. High-resolution three-dimensional observational data of water vapor and cloud water, which could be used for testing them, are missing. We explore the potential of ground-based re...

  19. Gamma spectrometry; level schemes

    International Nuclear Information System (INIS)

    Blachot, J.; Bocquet, J.P.; Monnand, E.; Schussler, F.

    1977-01-01

    The research presented dealt with: a new beta emitter, isomer of 131 Sn; the 136 I levels fed through the radioactive decay of 136 Te (20.9s); the A=145 chain (β decay of Ba, La and Ce, and level schemes for 145 La, 145 Ce, 145 Pr); the A=47 chain (La and Ce, β decay, and the level schemes of 147 Ce and 147 Pr) [fr

  20. Scheme of energy utilities

    International Nuclear Information System (INIS)

    2002-04-01

    This scheme defines the objectives relative to the renewable energies and the rational use of the energy in the framework of the national energy policy. It evaluates the needs and the potentialities of the regions and preconizes the actions between the government and the territorial organizations. The document is presented in four parts: the situation, the stakes and forecasts; the possible actions for new measures; the scheme management and the regional contributions analysis. (A.L.B.)

  1. 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.

  2. 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.

  3. 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.

  4. 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...

  5. 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.

  6. 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...

  7. 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.

  8. 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: .

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. 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

  14. 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.

  15. 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.

  16. 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.

  17. Towards Symbolic Encryption Schemes

    DEFF Research Database (Denmark)

    Ahmed, Naveed; Jensen, Christian D.; Zenner, Erik

    2012-01-01

    , namely an authenticated encryption scheme that is secure under chosen ciphertext attack. Therefore, many reasonable encryption schemes, such as AES in the CBC or CFB mode, are not among the implementation options. In this paper, we report new attacks on CBC and CFB based implementations of the well......Symbolic encryption, in the style of Dolev-Yao models, is ubiquitous in formal security models. In its common use, encryption on a whole message is specified as a single monolithic block. From a cryptographic perspective, however, this may require a resource-intensive cryptographic algorithm......-known Needham-Schroeder and Denning-Sacco protocols. To avoid such problems, we advocate the use of refined notions of symbolic encryption that have natural correspondence to standard cryptographic encryption schemes....

  18. Compact Spreader Schemes

    Energy Technology Data Exchange (ETDEWEB)

    Placidi, M.; Jung, J. -Y.; Ratti, A.; Sun, C.

    2014-07-25

    This paper describes beam distribution schemes adopting a novel implementation based on low amplitude vertical deflections combined with horizontal ones generated by Lambertson-type septum magnets. This scheme offers substantial compactness in the longitudinal layouts of the beam lines and increased flexibility for beam delivery of multiple beam lines on a shot-to-shot basis. Fast kickers (FK) or transverse electric field RF Deflectors (RFD) provide the low amplitude deflections. Initially proposed at the Stanford Linear Accelerator Center (SLAC) as tools for beam diagnostics and more recently adopted for multiline beam pattern schemes, RFDs offer repetition capabilities and a likely better amplitude reproducibility when compared to FKs, which, in turn, offer more modest financial involvements both in construction and operation. Both solutions represent an ideal approach for the design of compact beam distribution systems resulting in space and cost savings while preserving flexibility and beam quality.

  19. 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.

  20. BIBLIOGRAPHY ON INDIVIDUALIZED INSTRUCTION.

    Science.gov (United States)

    Harvard Univ., Cambridge, MA. Graduate School of Education.

    THIS BIBLIOGRAPHY LISTS MATERIAL ON VARIOUS ASPECTS OF INDIVIDUALIZED INSTRUCTION. APPROXIMATELY 85 UNANNOTATED REFERENCES ARE PROVIDED TO DOCUMENTS DATING FROM 1958 TO 1966. JOURNALS, BOOKS, AND REPORT MATERIALS ARE LISTED. SUBJECT AREAS INCLUDED ARE PROGRAMED INSTRUCTION, TEACHING MACHINES, RESPONSE MODE, SELF-INSTRUCTION, AND COMPUTER-ASSISTED…

  1. The Instructional Capacitor

    Science.gov (United States)

    Walton, Elizabeth

    2012-01-01

    Many administrators are so overwhelmed by the basic responsibilities of their daily work that there seems to be little or no time left for providing quality leadership in instruction. Instead, schools employ department chairs, instructional specialists, and coordinators to provide instructional leadership. How can administrators find time in the…

  2. New analytic unitarization schemes

    International Nuclear Information System (INIS)

    Cudell, J.-R.; Predazzi, E.; Selyugin, O. V.

    2009-01-01

    We consider two well-known classes of unitarization of Born amplitudes of hadron elastic scattering. The standard class, which saturates at the black-disk limit includes the standard eikonal representation, while the other class, which goes beyond the black-disk limit to reach the full unitarity circle, includes the U matrix. It is shown that the basic properties of these schemes are independent of the functional form used for the unitarization, and that U matrix and eikonal schemes can be extended to have similar properties. A common form of unitarization is proposed interpolating between both classes. The correspondence with different nonlinear equations are also briefly examined.

  3. 4. Payment Schemes

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 2. Electronic Commerce - Payment Schemes. V Rajaraman. Series Article Volume 6 Issue 2 February 2001 pp 6-13. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/006/02/0006-0013 ...

  4. Contract saving schemes

    NARCIS (Netherlands)

    Ronald, R.; Smith, S.J.; Elsinga, M.; Eng, O.S.; Fox O'Mahony, L.; Wachter, S.

    2012-01-01

    Contractual saving schemes for housing are institutionalised savings programmes normally linked to rights to loans for home purchase. They are diverse types as they have been developed differently in each national context, but normally fall into categories of open, closed, compulsory, and ‘free

  5. Alternative reprocessing schemes evaluation

    International Nuclear Information System (INIS)

    1979-02-01

    This paper reviews the parameters which determine the inaccessibility of the plutonium in reprocessing plants. Among the various parameters, the physical and chemical characteristics of the materials, the various processing schemes and the confinement are considered. The emphasis is placed on that latter parameter, and the advantages of an increased confinement in the socalled PIPEX reprocessing plant type are presented

  6. Introduction to association schemes

    NARCIS (Netherlands)

    Seidel, J.J.

    1991-01-01

    The present paper gives an introduction to the theory of association schemes, following Bose-Mesner (1959), Biggs (1974), Delsarte (1973), Bannai-Ito (1984) and Brouwer-Cohen-Neumaier (1989). Apart from definitions and many examples, also several proofs and some problems are included. The paragraphs

  7. Reaction schemes of immunoanalysis

    International Nuclear Information System (INIS)

    Delaage, M.; Barbet, J.

    1991-01-01

    The authors apply a general theory for multiple equilibria to the reaction schemes of immunoanalysis, competition and sandwich. This approach allows the manufacturer to optimize the system and provide the user with interpolation functions for the standard curve and its first derivative as well, thus giving access to variance [fr

  8. Alternative health insurance schemes

    DEFF Research Database (Denmark)

    Keiding, Hans; Hansen, Bodil O.

    2002-01-01

    In this paper, we present a simple model of health insurance with asymmetric information, where we compare two alternative ways of organizing the insurance market. Either as a competitive insurance market, where some risks remain uninsured, or as a compulsory scheme, where however, the level...... competitive insurance; this situation turns out to be at least as good as either of the alternatives...

  9. 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...

  10. 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…

  11. 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...

  12. Low-storage implicit/explicit Runge-Kutta schemes for the simulation of stiff high-dimensional ODE systems

    Science.gov (United States)

    Cavaglieri, Daniele; Bewley, Thomas

    2015-04-01

    Implicit/explicit (IMEX) Runge-Kutta (RK) schemes are effective for time-marching ODE systems with both stiff and nonstiff terms on the RHS; such schemes implement an (often A-stable or better) implicit RK scheme for the stiff part of the ODE, which is often linear, and, simultaneously, a (more convenient) explicit RK scheme for the nonstiff part of the ODE, which is often nonlinear. Low-storage RK schemes are especially effective for time-marching high-dimensional ODE discretizations of PDE systems on modern (cache-based) computational hardware, in which memory management is often the most significant computational bottleneck. In this paper, we develop and characterize eight new low-storage implicit/explicit RK schemes which have higher accuracy and better stability properties than the only low-storage implicit/explicit RK scheme available previously, the venerable second-order Crank-Nicolson/Runge-Kutta-Wray (CN/RKW3) algorithm that has dominated the DNS/LES literature for the last 25 years, while requiring similar storage (two, three, or four registers of length N) and comparable floating-point operations per timestep.

  13. 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

  14. 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.

  15. On Converting Secret Sharing Scheme to Visual Secret Sharing Scheme

    Directory of Open Access Journals (Sweden)

    Wang Daoshun

    2010-01-01

    Full Text Available Abstract Traditional Secret Sharing (SS schemes reconstruct secret exactly the same as the original one but involve complex computation. Visual Secret Sharing (VSS schemes decode the secret without computation, but each share is m times as big as the original and the quality of the reconstructed secret image is reduced. Probabilistic visual secret sharing (Prob.VSS schemes for a binary image use only one subpixel to share the secret image; however the probability of white pixels in a white area is higher than that in a black area in the reconstructed secret image. SS schemes, VSS schemes, and Prob. VSS schemes have various construction methods and advantages. This paper first presents an approach to convert (transform a -SS scheme to a -VSS scheme for greyscale images. The generation of the shadow images (shares is based on Boolean XOR operation. The secret image can be reconstructed directly by performing Boolean OR operation, as in most conventional VSS schemes. Its pixel expansion is significantly smaller than that of VSS schemes. The quality of the reconstructed images, measured by average contrast, is the same as VSS schemes. Then a novel matrix-concatenation approach is used to extend the greyscale -SS scheme to a more general case of greyscale -VSS scheme.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  3. 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.

  4. 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.

  5. Selectively strippable paint schemes

    Science.gov (United States)

    Stein, R.; Thumm, D.; Blackford, Roger W.

    1993-03-01

    In order to meet the requirements of more environmentally acceptable paint stripping processes many different removal methods are under evaluation. These new processes can be divided into mechanical and chemical methods. ICI has developed a paint scheme with intermediate coat and fluid resistant polyurethane topcoat which can be stripped chemically in a short period of time with methylene chloride free and phenol free paint strippers.

  6. Scalable Nonlinear Compact Schemes

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Debojyoti [Argonne National Lab. (ANL), Argonne, IL (United States); Constantinescu, Emil M. [Univ. of Chicago, IL (United States); Brown, Jed [Univ. of Colorado, Boulder, CO (United States)

    2014-04-01

    In this work, we focus on compact schemes resulting in tridiagonal systems of equations, specifically the fifth-order CRWENO scheme. We propose a scalable implementation of the nonlinear compact schemes by implementing a parallel tridiagonal solver based on the partitioning/substructuring approach. We use an iterative solver for the reduced system of equations; however, we solve this system to machine zero accuracy to ensure that no parallelization errors are introduced. It is possible to achieve machine-zero convergence with few iterations because of the diagonal dominance of the system. The number of iterations is specified a priori instead of a norm-based exit criterion, and collective communications are avoided. The overall algorithm thus involves only point-to-point communication between neighboring processors. Our implementation of the tridiagonal solver differs from and avoids the drawbacks of past efforts in the following ways: it introduces no parallelization-related approximations (multiprocessor solutions are exactly identical to uniprocessor ones), it involves minimal communication, the mathematical complexity is similar to that of the Thomas algorithm on a single processor, and it does not require any communication and computation scheduling.

  7. Long multiplication by instruction sequences with backward jump instructions

    NARCIS (Netherlands)

    Bergstra, J.A.; Middelburg, C.A.

    2013-01-01

    For each function on bit strings, its restriction to bit strings of any given length can be computed by a finite instruction sequence that contains only instructions to set and get the content of Boolean registers, forward jump instructions, and a termination instruction. Backward jump instructions

  8. ESCAP mobile training scheme.

    Science.gov (United States)

    Yasas, F M

    1977-01-01

    In response to a United Nations resolution, the Mobile Training Scheme (MTS) was set up to provide training to the trainers of national cadres engaged in frontline and supervisory tasks in social welfare and rural development. The training is innovative in its being based on an analysis of field realities. The MTS team consisted of a leader, an expert on teaching methods and materials, and an expert on action research and evaluation. The country's trainers from different departments were sent to villages to work for a short period and to report their problems in fulfilling their roles. From these grass roots experiences, they made an analysis of the job, determining what knowledge, attitude and skills it required. Analysis of daily incidents and problems were used to produce indigenous teaching materials drawn from actual field practice. How to consider the problems encountered through government structures for policy making and decisions was also learned. Tasks of the students were to identify the skills needed for role performance by job analysis, daily diaries and project histories; to analyze the particular community by village profiles; to produce indigenous teaching materials; and to practice the role skills by actual role performance. The MTS scheme was tried in Nepal in 1974-75; 3 training programs trained 25 trainers and 51 frontline workers; indigenous teaching materials were created; technical papers written; and consultations were provided. In Afghanistan the scheme was used in 1975-76; 45 participants completed the training; seminars were held; and an ongoing Council was created. It is hoped that the training program will be expanded to other countries.

  9. Bonus schemes and trading activity

    NARCIS (Netherlands)

    Pikulina, E.S.; Renneboog, L.D.R.; ter Horst, J.R.; Tobler, P.N.

    2014-01-01

    Little is known about how different bonus schemes affect traders' propensity to trade and which bonus schemes improve traders' performance. We study the effects of linear versus threshold bonus schemes on traders' behavior. Traders buy and sell shares in an experimental stock market on the basis of

  10. Succesful labelling schemes

    DEFF Research Database (Denmark)

    Juhl, Hans Jørn; Stacey, Julia

    2001-01-01

    . In the spring of 2001 MAPP carried out an extensive consumer study with special emphasis on the Nordic environmentally friendly label 'the swan'. The purpose was to find out how much consumers actually know and use various labelling schemes. 869 households were contacted and asked to fill in a questionnaire...... it into consideration when I go shopping. The respondent was asked to pick the most suitable answer, which described her use of each label. 29% - also called 'the labelling blind' - responded that they basically only knew the recycling label and the Government controlled organic label 'Ø-mærket'. Another segment of 6...

  11. Scheme of stepmotor control

    International Nuclear Information System (INIS)

    Grashilin, V.A.; Karyshev, Yu.Ya.

    1982-01-01

    A 6-cycle scheme of step motor is described. The block-diagram and the basic circuit of the step motor control are presented. The step motor control comprises a pulse shaper, electronic commutator and power amplifiers. The step motor supply from 6-cycle electronic commutator provides for higher reliability and accuracy than from 3-cycle commutator. The control of step motor work is realised by the program given by the external source of control signals. Time-dependent diagrams for step motor control are presented. The specifications of the step-motor is given

  12. 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

  13. 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)

  14. 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.

  15. 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%.

  16. 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.

  17. 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.

  18. Programmed Instruction Revisited.

    Science.gov (United States)

    Skinner, B. F.

    1986-01-01

    Discusses the history and development of teaching machines, invented to restore the important features of personalized instruction as public school class size increased. Examines teaching and learning problems over the past 50 years, including motivation, attention, appreciation, discovery, and creativity in relation to programmed instruction.…

  19. Fashions in Instructional Development.

    Science.gov (United States)

    Knapper, Christopher K.

    This paper on instructional development notes the trend toward teaching improvement efforts, classifies instructional development centers in terms of their differing philosophies of operation, and identifies some general problems that have been encountered in institutional efforts to improve teaching and learning. Centers in North America, Europe,…

  20. Packet reversed packet combining scheme

    International Nuclear Information System (INIS)

    Bhunia, C.T.

    2006-07-01

    The packet combining scheme is a well defined simple error correction scheme with erroneous copies at the receiver. It offers higher throughput combined with ARQ protocols in networks than that of basic ARQ protocols. But packet combining scheme fails to correct errors when the errors occur in the same bit locations of two erroneous copies. In the present work, we propose a scheme that will correct error if the errors occur at the same bit location of the erroneous copies. The proposed scheme when combined with ARQ protocol will offer higher throughput. (author)

  1. A full quantum network scheme

    International Nuclear Information System (INIS)

    Ma Hai-Qiang; Wei Ke-Jin; Yang Jian-Hui; Li Rui-Xue; Zhu Wu

    2014-01-01

    We present a full quantum network scheme using a modified BB84 protocol. Unlike other quantum network schemes, it allows quantum keys to be distributed between two arbitrary users with the help of an intermediary detecting user. Moreover, it has good expansibility and prevents all potential attacks using loopholes in a detector, so it is more practical to apply. Because the fiber birefringence effects are automatically compensated, the scheme is distinctly stable in principle and in experiment. The simple components for every user make our scheme easier for many applications. The experimental results demonstrate the stability and feasibility of this scheme. (general)

  2. 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.

  3. New CERN Health Insurance Scheme (CHIS) forms

    CERN Multimedia

    HR Department

    2015-01-01

    New versions of the following forms for claims and requests to the CERN Health Insurance Scheme (CHIS) have been released:   form for claiming reimbursement of medical expenses,   form for requesting advance reimbursement, and   dental estimate form (for treatments foreseen to exceed 800 CHF).   The new forms are available in French and English. They can either be completed electronically before being printed and signed, or completed in paper form. New detailed instructions can be found at the back of the claim form; CHIS members are invited to read them carefully. The electronic versions (PDF) of all the forms are available on the CHIS website and on the UNIQA Member Portal. CHIS Members are requested to use these new forms forthwith and to discard any previous version. Questions regarding the above should be addressed directly to UNIQA (72730 or 022.718 63 00 or uniqa.assurances@cern.ch).

  4. 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...

  5. Using Principles of Programmed Instruction

    Science.gov (United States)

    Huffman, Harry

    1971-01-01

    Although programmed instruction in accounting is available, it is limited in scope and in acceptance. Teachers, however, may apply principles of programming to the individualizing of instruction. (Author)

  6. Using Interactive Video Instruction To Enhance Public Speaking Instruction.

    Science.gov (United States)

    Cronin, Michael W.; Kennan, William R.

    Noting that interactive video instruction (IVI) should not and cannot replace classroom instruction, this paper offers an introduction to interactive video instruction as an innovative technology that can be used to expand pedagogical opportunities in public speaking instruction. The paper: (1) defines the distinctive features of IVI; (2) assesses…

  7. A distributed authentication and authorization scheme for in-network big data sharing

    Directory of Open Access Journals (Sweden)

    Ruidong Li

    2017-11-01

    Full Text Available Big data has a strong demand for a network infrastructure with the capability to support data sharing and retrieval efficiently. Information-centric networking (ICN is an emerging approach to satisfy this demand, where big data is cached ubiquitously in the network and retrieved using data names. However, existing authentication and authorization schemes rely mostly on centralized servers to provide certification and mediation services for data retrieval. This causes considerable traffic overhead for the secure distributed sharing of data. To solve this problem, we employ identity-based cryptography (IBC to propose a Distributed Authentication and Authorization Scheme (DAAS, where an identity-based signature (IBS is used to achieve distributed verifications of the identities of publishers and users. Moreover, Ciphertext-Policy Attribute-based encryption (CP-ABE is used to enable the distributed and fine-grained authorization. DAAS consists of three phases: initialization, secure data publication, and secure data retrieval, which seamlessly integrate authentication and authorization with the interest/data communication paradigm in ICN. In particular, we propose trustworthy registration and Network Operator and Authority Manifest (NOAM dissemination to provide initial secure registration and enable efficient authentication for global data retrieval. Meanwhile, Attribute Manifest (AM distribution coupled with automatic attribute update is proposed to reduce the cost of attribute retrieval. We examine the performance of the proposed DAAS, which shows that it can achieve a lower bandwidth cost than existing schemes.

  8. Modified Aggressive Packet Combining Scheme

    International Nuclear Information System (INIS)

    Bhunia, C.T.

    2010-06-01

    In this letter, a few schemes are presented to improve the performance of aggressive packet combining scheme (APC). To combat error in computer/data communication networks, ARQ (Automatic Repeat Request) techniques are used. Several modifications to improve the performance of ARQ are suggested by recent research and are found in literature. The important modifications are majority packet combining scheme (MjPC proposed by Wicker), packet combining scheme (PC proposed by Chakraborty), modified packet combining scheme (MPC proposed by Bhunia), and packet reversed packet combining (PRPC proposed by Bhunia) scheme. These modifications are appropriate for improving throughput of conventional ARQ protocols. Leung proposed an idea of APC for error control in wireless networks with the basic objective of error control in uplink wireless data network. We suggest a few modifications of APC to improve its performance in terms of higher throughput, lower delay and higher error correction capability. (author)

  9. Transmission usage cost allocation schemes

    International Nuclear Information System (INIS)

    Abou El Ela, A.A.; El-Sehiemy, R.A.

    2009-01-01

    This paper presents different suggested transmission usage cost allocation (TCA) schemes to the system individuals. Different independent system operator (ISO) visions are presented using the proportional rata and flow-based TCA methods. There are two proposed flow-based TCA schemes (FTCA). The first FTCA scheme generalizes the equivalent bilateral exchanges (EBE) concepts for lossy networks through two-stage procedure. The second FTCA scheme is based on the modified sensitivity factors (MSF). These factors are developed from the actual measurements of power flows in transmission lines and the power injections at different buses. The proposed schemes exhibit desirable apportioning properties and are easy to implement and understand. Case studies for different loading conditions are carried out to show the capability of the proposed schemes for solving the TCA problem. (author)

  10. 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.

  11. 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...

  12. Computer Assisted Instruction

    Science.gov (United States)

    Higgins, Paul

    1976-01-01

    Methodology for developing a computer assisted instruction (CAI) lesson (scripting, programing, and testing) is reviewed. A project done by Informatics Education Ltd. (IEL) for the Department of National Defense (DND) is used as an example. (JT)

  13. Bibliographic Instruction : A Webliography

    Directory of Open Access Journals (Sweden)

    2004-09-01

    Full Text Available A Webliography about the Bibliographic Instruction, it collects a variety of internet resources divided to main categories; directories, articles, bibliographies, organization, mailing lists, and interest groups.

  14. Coordinated renewable energy support schemes

    DEFF Research Database (Denmark)

    Morthorst, P.E.; Jensen, S.G.

    2006-01-01

    . The first example covers countries with regional power markets that also regionalise their support schemes, the second countries with separate national power markets that regionalise their support schemes. The main findings indicate that the almost ideal situation exists if the region prior to regionalising...

  15. CANONICAL BACKWARD DIFFERENTIATION SCHEMES FOR ...

    African Journals Online (AJOL)

    This paper describes a new nonlinear backward differentiation schemes for the numerical solution of nonlinear initial value problems of first order ordinary differential equations. The schemes are based on rational interpolation obtained from canonical polynomials. They are A-stable. The test problems show that they give ...

  16. 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.

  17. Inclusive differentiated instruction

    Directory of Open Access Journals (Sweden)

    Jerković Ljiljana S.

    2017-01-01

    Full Text Available Inclusive differentiated instruction is a new model of didactic instruction, theoretically described and established in this paper for the first time, after being experimentally verified through teaching of the mother tongue (instruction in reading and literature. Inclusive individually planned instruction is based on a phenomenological and constructivist didactic instructional paradigm. This type of teaching is essentially developmental and person-oriented. The key stages of inclusive differentiated instruction of literature are: 1 recognition of individual students' potential and educational needs regarding reading and work on literary texts; 2 planning and preparation of inclusive individually planned instruction in reading and literature; 3 actual class teaching of lessons thus prepared; and 4 evaluation of the student achievement following inclusive differentiated instruction in reading and literature. A highly important element of the planning and preparation of inclusive differentiated instruction is the creation of student profiles and inclusive individualized syllabi. Individualized syllabi specify the following: 1. a brief student profile; 2. the student position on the continuum of the learning outcomes of instruction in the Serbian language; 3. reverse-engineered macro-plan stages of instruction in the Serbian language (3.1. identifying expected outcomes and fundamental qualities of learners' work, 3.2. defining acceptable proofs of their realisation, 3.3. planning learning and teaching experiences, and 3.4. providing material and technical requisites for teaching; 4 the contents and procedure of individualized lessons targeting the student; 5 a plan of syllabus implementation monitoring and evaluation. The continuum of the learning outcomes of inclusive differentiated instruction in literature exists at three main levels, A, B and C. The three levels are: A reading techniques and learning about the main literary theory concepts; B

  18. hybrid modulation scheme fo rid modulation scheme fo dulation

    African Journals Online (AJOL)

    eobe

    control technique is done through simulations and ex control technique .... HYBRID MODULATION SCHEME FOR CASCADED H-BRIDGE INVERTER CELLS. C. I. Odeh ..... and OR operations. Referring to ... MATLAB/SIMULINK environment.

  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. Good governance for pension schemes

    CERN Document Server

    Thornton, Paul

    2011-01-01

    Regulatory and market developments have transformed the way in which UK private sector pension schemes operate. This has increased demands on trustees and advisors and the trusteeship governance model must evolve in order to remain fit for purpose. This volume brings together leading practitioners to provide an overview of what today constitutes good governance for pension schemes, from both a legal and a practical perspective. It provides the reader with an appreciation of the distinctive characteristics of UK occupational pension schemes, how they sit within the capital markets and their social and fiduciary responsibilities. Providing a holistic analysis of pension risk, both from the trustee and the corporate perspective, the essays cover the crucial role of the employer covenant, financing and investment risk, developments in longevity risk hedging and insurance de-risking, and best practice scheme administration.

  3. Optimum RA reactor fuelling scheme

    International Nuclear Information System (INIS)

    Strugar, P.; Nikolic, V.

    1965-10-01

    Ideal reactor refueling scheme can be achieved only by continuous fuel elements movement in the core, which is not possible, and thus approximations are applied. One of the possible approximations is discontinuous movement of fuel elements groups in radial direction. This enables higher burnup especially if axial exchange is possible. Analysis of refueling schemes in the RA reactor core and schemes with mixing the fresh and used fuel elements show that 30% higher burnup can be achieved by applying mixing, and even 40% if reactivity due to decrease in experimental space is taken into account. Up to now, mean burnup of 4400 MWd/t has been achieved, and the proposed fueling scheme with reduction of experimental space could achieve mean burnup of 6300 MWd/t which means about 25 Mwd/t per fuel channel [sr

  4. A Novel Iris Segmentation Scheme

    Directory of Open Access Journals (Sweden)

    Chen-Chung Liu

    2014-01-01

    Full Text Available One of the key steps in the iris recognition system is the accurate iris segmentation from its surrounding noises including pupil, sclera, eyelashes, and eyebrows of a captured eye-image. This paper presents a novel iris segmentation scheme which utilizes the orientation matching transform to outline the outer and inner iris boundaries initially. It then employs Delogne-Kåsa circle fitting (instead of the traditional Hough transform to further eliminate the outlier points to extract a more precise iris area from an eye-image. In the extracted iris region, the proposed scheme further utilizes the differences in the intensity and positional characteristics of the iris, eyelid, and eyelashes to detect and delete these noises. The scheme is then applied on iris image database, UBIRIS.v1. The experimental results show that the presented scheme provides a more effective and efficient iris segmentation than other conventional methods.

  5. Numerical schemes for explosion hazards

    International Nuclear Information System (INIS)

    Therme, Nicolas

    2015-01-01

    In nuclear facilities, internal or external explosions can cause confinement breaches and radioactive materials release in the environment. Hence, modeling such phenomena is crucial for safety matters. Blast waves resulting from explosions are modeled by the system of Euler equations for compressible flows, whereas Navier-Stokes equations with reactive source terms and level set techniques are used to simulate the propagation of flame front during the deflagration phase. The purpose of this thesis is to contribute to the creation of efficient numerical schemes to solve these complex models. The work presented here focuses on two major aspects: first, the development of consistent schemes for the Euler equations, then the buildup of reliable schemes for the front propagation. In both cases, explicit in time schemes are used, but we also introduce a pressure correction scheme for the Euler equations. Staggered discretization is used in space. It is based on the internal energy formulation of the Euler system, which insures its positivity and avoids tedious discretization of the total energy over staggered grids. A discrete kinetic energy balance is derived from the scheme and a source term is added in the discrete internal energy balance equation to preserve the exact total energy balance at the limit. High order methods of MUSCL type are used in the discrete convective operators, based solely on material velocity. They lead to positivity of density and internal energy under CFL conditions. This ensures that the total energy cannot grow and we can furthermore derive a discrete entropy inequality. Under stability assumptions of the discrete L8 and BV norms of the scheme's solutions one can prove that a sequence of converging discrete solutions necessarily converges towards the weak solution of the Euler system. Besides it satisfies a weak entropy inequality at the limit. Concerning the front propagation, we transform the flame front evolution equation (the so called

  6. Apparel. Teacher's Instructional Guide.

    Science.gov (United States)

    Rambo, Patti

    This instructional guide for a one-half credit technological laboratory course for grades 10-12 focuses on apparel from the perspectives of personal decision making related to apparel, the apparel industry, and career preparation. Introductory materials are a course description; overview of course design; facilities, equipment, and resources; and…

  7. Instructional Guidelines. Welding.

    Science.gov (United States)

    Fordyce, H. L.; Doshier, Dale

    Using the standards of the American Welding Society and the American Society of Mechanical Engineers, this welding instructional guidelines manual presents a course of study in accordance with the current practices in industry. Intended for use in welding programs now practiced within the Federal Prison System, the phases of the program are…

  8. Windows into Instructional Practice

    Science.gov (United States)

    Steinbacher-Reed, Christina; Rotella, Sam A.

    2017-01-01

    Administrators are often removed from the daily instructional realities in classrooms, while teachers aren't given enough opportunities to lead in their schools, write Christina Steinbacher-Reed and Sam A. Rotella Jr. The result is a wall that prevents the two parties from collaborating in a way that improves school culture, teaching practices,…

  9. INSTRUCTIONAL MATERIALS CATALOG.

    Science.gov (United States)

    Ohio Vocational Agriculture Instructional Materials Service, Columbus.

    THE TITLE, IDENTIFICATION NUMBER, DATE OF PUBLICATION, PAGINATION, A BRIEF DESCRIPTION, AND PRICE ARE GIVEN FOR EACH OF THE INSTRUCTIONAL MATERIALS AND AUDIOVISUAL AIDS INCLUDED IN THIS CATALOG. TOPICS COVERED ARE FIELD CORPS, HORTICULTURE, ANIMAL SCIENCE, SOILS, AGRICULTURAL ENGINEERING, AND FARMING PROGRAMS. AN ORDER FORM IS INCLUDED. (JM)

  10. Computers in writing instruction

    NARCIS (Netherlands)

    Schwartz, Helen J.; van der Geest, Thea; Smit-Kreuzen, Marlies

    1992-01-01

    For computers to be useful in writing instruction, innovations should be valuable for students and feasible for teachers to implement. Research findings yield contradictory results in measuring the effects of different uses of computers in writing, in part because of the methodological complexity of

  11. Gaze Interactive Building Instructions

    DEFF Research Database (Denmark)

    Hansen, John Paulin; Ahmed, Zaheer; Mardanbeigi, Diako

    We combine eye tracking technology and mobile tablets to support hands-free interaction with digital building instructions. As a proof-of-concept we have developed a small interactive 3D environment where one can interact with digital blocks by gaze, keystroke and head gestures. Blocks may be moved...

  12. Job Instruction Training.

    Science.gov (United States)

    Pfau, Richard H.

    Job Instruction Training (JIT) is a step-by-step, relatively simple technique used to train employees on the job. It is especially suitable for teaching manual skills or procedures; the trainer is usually an employee's supervisor but can be a co-worker. The JIT technique consists of a series of steps that a supervisor or other instructor follows…

  13. Nuclear Energy. Instructional Materials.

    Science.gov (United States)

    Jordan, Kenneth; Thessing, Dan

    This document is one of five learning packets on alternative energy (see note) developed as part of a descriptive curriculum research project in Arkansas. The overall objectives of the learning packets are to improve the level of instruction in the alternative energies by vocational exploration teachers, and to facilitate the integration of new…

  14. Wind Power. Instructional Materials.

    Science.gov (United States)

    Jordan, Kenneth; Thessing, Dan

    This document is one of five learning packets on alternative energy developed as part of a descriptive curriculum research project in Arkansas (see note). The overall objectives of the learning packets are to improve the level of instruction in the alternative energies by vocational exploration teachers, and to facilitate the integration of new…

  15. Instructional Psychology 1976 - 1981,

    Science.gov (United States)

    1982-06-01

    business it is to carry out applied work in the design of instructional content and delivery. These organizations include specialized divisions of...34learning disabilities" label: An experimental analysis. Comtemporary Educational Psychology, 1977, 2, 292-297. Allington, R. L. Sensitivity to

  16. Reviews in instructional video

    NARCIS (Netherlands)

    van der Meij, Hans

    2017-01-01

    This study investigates the effectiveness of a video tutorial for software training whose construction was based on a combination of insights from multimedia learning and Demonstration-Based Training. In the videos, a model of task performance was enhanced with instructional features that were

  17. Computer-assisted instruction

    NARCIS (Netherlands)

    Voogt, J.; Fisser, P.; Wright, J.D.

    2015-01-01

    Since the early days of computer technology in education in the 1960s, it was claimed that computers can assist instructional practice and hence improve student learning. Since then computer technology has developed, and its potential for education has increased. In this article, we first discuss

  18. Scaffolding in Assisted Instruction

    Directory of Open Access Journals (Sweden)

    2007-01-01

    Full Text Available On-The-Job Training, developed as direct instruction, is one of the earliest forms of training. This method is still widely in use today because it requires only a person who knows how to do the task, and the tools the person uses to do the task. This paper is intended to be a study of the methods used in education in Knowledge Society, with more specific aspects in training the trainers; as a result of this approach, it promotes scaffolding in assisted instruction as a reflection of the digital age for the learning process. Training the trainers in old environment with default techniques and designing the learning process in assisted instruction, as an application of the Vygotskian concept of the zone of proximal development (ZPD to the area of computer literacy for the younger users, generate diversity in educational communities and requires standards for technology infrastructure, standards for the content, developed as a concepts map, and applications for personalized in-struction, based on ZPD theory.

  19. Characteristics of Instructional Videos

    Science.gov (United States)

    Beheshti, Mobina; Taspolat, Ata; Kaya, Omer Sami; Sapanca, Hamza Fatih

    2018-01-01

    Nowadays, video plays a significant role in education in terms of its integration into traditional classes, the principal delivery system of information in classes particularly in online courses as well as serving as a foundation of many blended classes. Hence, education is adopting a modern approach of instruction with the target of moving away…

  20. Facility transition instruction

    International Nuclear Information System (INIS)

    Morton, M.R.

    1997-01-01

    The Bechtel Hanford, Inc. facility transition instruction was initiated in response to the need for a common, streamlined process for facility transitions and to capture the knowledge and experience that has accumulated over the last few years. The instruction serves as an educational resource and defines the process for transitioning facilities to long-term surveillance and maintenance (S and M). Generally, these facilities do not have identified operations missions and must be transitioned from operational status to a safe and stable configuration for long-term S and M. The instruction can be applied to a wide range of facilities--from process canyon complexes like the Plutonium Uranium Extraction Facility or B Plant, to stand-alone, lower hazard facilities like the 242B/BL facility. The facility transition process is implemented (under the direction of the US Department of Energy, Richland Operations Office [RL] Assistant Manager-Environmental) by Bechtel Hanford, Inc. management, with input and interaction with the appropriate RL division and Hanford site contractors as noted in the instruction. The application of the steps identified herein and the early participation of all organizations involved are expected to provide a cost-effective, safe, and smooth transition from operational status to deactivation and S and M for a wide range of Hanford Site facilities

  1. Paratransit: An Instructional Module.

    Science.gov (United States)

    Scalici, Anthony

    A concept-based introduction to paratransit is provided in this instructional module for undergraduate and graduate transportation-related courses for disciplines such as engineering, business, marketing, and technology. The concept of paratransit generally refers to modes of transportation other than mass transit and solo-driven automobiles. The…

  2. Listening strategies instruction

    DEFF Research Database (Denmark)

    Nogueroles López, Marta

    2017-01-01

    , who presented similar level of Spanish, needs, educational and cultural background, but did not receive such a training. The listening strategies instruction consisted in integrating the development of listening strategies into a regular course of Spanish as a foreign language. Data referring...

  3. Inquiry-Oriented Instruction: A Conceptualization of the Instructional Principles

    Science.gov (United States)

    Kuster, George; Johnson, Estrella; Keene, Karen; Andrews-Larson, Christine

    2018-01-01

    Research has highlighted that inquiry-based learning (IBL) instruction leads to many positive student outcomes in undergraduate mathematics. Although this research points to the value of IBL instruction, the practices of IBL instructors are not well-understood. Here, we offer a characterization of a particular form of IBL instruction:…

  4. Breeding schemes in reindeer husbandry

    Directory of Open Access Journals (Sweden)

    Lars Rönnegård

    2003-04-01

    Full Text Available The objective of the paper was to investigate annual genetic gain from selection (G, and the influence of selection on the inbreeding effective population size (Ne, for different possible breeding schemes within a reindeer herding district. The breeding schemes were analysed for different proportions of the population within a herding district included in the selection programme. Two different breeding schemes were analysed: an open nucleus scheme where males mix and mate between owner flocks, and a closed nucleus scheme where the males in non-selected owner flocks are culled to maximise G in the whole population. The theory of expected long-term genetic contributions was used and maternal effects were included in the analyses. Realistic parameter values were used for the population, modelled with 5000 reindeer in the population and a sex ratio of 14 adult females per male. The standard deviation of calf weights was 4.1 kg. Four different situations were explored and the results showed: 1. When the population was randomly culled, Ne equalled 2400. 2. When the whole population was selected on calf weights, Ne equalled 1700 and the total annual genetic gain (direct + maternal in calf weight was 0.42 kg. 3. For the open nucleus scheme, G increased monotonically from 0 to 0.42 kg as the proportion of the population included in the selection programme increased from 0 to 1.0, and Ne decreased correspondingly from 2400 to 1700. 4. In the closed nucleus scheme the lowest value of Ne was 1300. For a given proportion of the population included in the selection programme, the difference in G between a closed nucleus scheme and an open one was up to 0.13 kg. We conclude that for mass selection based on calf weights in herding districts with 2000 animals or more, there are no risks of inbreeding effects caused by selection.

  5. Peano—A Traversal and Storage Scheme for Octree-Like Adaptive Cartesian Multiscale Grids

    KAUST Repository

    Weinzierl, Tobias

    2011-01-01

    Almost all approaches to solving partial differential equations (PDEs) are based upon a spatial discretization of the computational domain-a grid. This paper presents an algorithm to generate, store, and traverse a hierarchy of d-dimensional Cartesian grids represented by a (k = 3)- spacetree, a generalization of the well-known octree concept, and it also shows the correctness of the approach. These grids may change their adaptive structure throughout the traversal. The algorithm uses 2d + 4 stacks as data structures for both cells and vertices, and the storage requirements for the pure grid reduce to one bit per vertex for both the complete grid connectivity structure and the multilevel grid relations. Since the traversal algorithm uses only stacks, the algorithm\\'s cache hit rate is continually higher than 99.9 percent, and the runtime per vertex remains almost constant; i.e., it does not depend on the overall number of vertices or the adaptivity pattern. We use the algorithmic approach as the fundamental concept for a mesh management for d-dimensional PDEs and for a matrix-free PDE solver represented by a compact discrete 3 d-point operator. In the latter case, one can implement a Jacobi smoother, a Krylov solver, or a geometric multigrid scheme within the presented traversal scheme which inherits the low memory requirements and the good memory access characteristics directly. © 2011 Society for Industrial and Applied Mathematics.

  6. Integrating a Trust Framework with a Distributed Certificate Validation Scheme for MANETs

    Directory of Open Access Journals (Sweden)

    Marias Giannis F

    2006-01-01

    Full Text Available Many trust establishment solutions in mobile ad hoc networks (MANETs rely on public key certificates. Therefore, they should be accompanied by an efficient mechanism for certificate revocation and validation. Ad hoc distributed OCSP for trust (ADOPT is a lightweight, distributed, on-demand scheme based on cached OCSP responses, which provides certificate status information to the nodes of a MANET. In this paper we discuss the ADOPT scheme and issues on its deployment over MANETs. We present some possible threats to ADOPT and suggest the use of a trust assessment and establishment framework, named ad hoc trust framework (ATF, to support ADOPT's robustness and efficiency. ADOPT is deployed as a trust-aware application that provides feedback to ATF, which calculates the trustworthiness of the peer nodes' functions and helps ADOPT to improve its performance by rapidly locating valid certificate status information. Moreover, we introduce the TrustSpan algorithm to reduce the overhead that ATF produces, and the TrustPath algorithm to identify and use trusted routes for propagating sensitive information, such as third parties' accusations. Simulation results show that ATF adds limited overhead compared to its efficiency in detecting and isolating malicious and selfish nodes. ADOPT's reliability is increased, since it can rapidly locate a legitimate response by using information provided by ATF.

  7. 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

  8. Instructional Leadership Practices in Singapore

    Science.gov (United States)

    Ng, Foo Seong David; Nguyen, Thanh Dong; Wong, Koon Siak Benjamin; Choy, Kim Weng William

    2015-01-01

    This paper presents a review of the literature on principal instructional leadership in Singapore. The authors investigated the dimensions of instructional leadership in the practices of Singapore principals and highlighted the strategies these leaders adopt to enact their instructional roles. Singapore principals were found to play an active role…

  9. Putting instruction sequences into effect

    NARCIS (Netherlands)

    Bergstra, J.A.

    2011-01-01

    An attempt is made to define the concept of execution of an instruction sequence. It is found to be a special case of directly putting into effect of an instruction sequence. Directly putting into effect of an instruction sequences comprises interpretation as well as execution. Directly putting into

  10. The Measurement of Instructional Accomplishments.

    Science.gov (United States)

    Fraley, Lawrence E.; Vargas, Ernest A.

    Instructional System Technology in recent years has been characterized by an increase in individualized instruction and the modularization of the curriculum. In traditional systems the learners are forced to take blocks of instruction the size of entire courses and these are much too large. The courses can now be broken down into conceptual…

  11. Intelligent Frameworks for Instructional Design.

    Science.gov (United States)

    Spector, J. Michael; And Others

    1992-01-01

    Presents a taxonomy describing various uses of artificial intelligence techniques in automated instructional development systems. Instructional systems development is discussed in relation to the design of computer-based instructional courseware; two systems being developed at the Air Force Armstrong Laboratory are reviewed; and further research…

  12. Very Long Instruction Word Processors

    Indian Academy of Sciences (India)

    Explicitly Parallel Instruction Computing (EPIC) is an instruction processing paradigm that has been in the spot- light due to its adoption by the next generation of Intel. Processors starting with the IA-64. The EPIC processing paradigm is an evolution of the Very Long Instruction. Word (VLIW) paradigm. This article gives an ...

  13. Motivational elements in user instructions

    NARCIS (Netherlands)

    Loorbach, N.R.

    2013-01-01

    Concerning the design of user instructions, two view can be distinguished. The traditional view considers instructions as purely instrumental documents. The more and more emerging affective view still assumes that above all, instructions should enable readers to perform tasks. But in order to

  14. Collation of chewing efficiency and dentures with diverse occlusal schemes

    Directory of Open Access Journals (Sweden)

    Vijay Kumar Peddinti

    2017-01-01

    Full Text Available Background: Rehabilitation of an edentulous patient nurtures satisfaction and this lies in the chewing ability provided by the prosthesis. Aim: To evaluate and compare the masticatory efficiencies of complete dentures with different occlusal schemes. Materials and Methods: Fourteen completely edentulous patients from the age group of 50-70 years were selected according to the inclusion criteria followed in this study. The dentures were made with three different occlusal schemes, i.e., anatomic occlusion without balancing, anatomic occlusion with balancing, and lingualized occlusion and stored in water till the date of denture insertion. Post-insertion instructions were given to the patients at the time of delivery of the dentures. Patients were recalled after seven days and then masticatory efficiency was performed. The test was performed using boiled peanuts and Sieve system. Statistical Analysis: One-way analysis of variance (ANOVA test and unpaired t-test were carried out. Results: The obtained masticatory efficiency values with anatomic occlusion without balancing, anatomic occlusion with balancing, and lingualized occlusion LO were analyzed using one-way ANOVA test and unpaired “t” test. The tests showed that lingualized scheme had highest masticatory efficiency. Conclusion: Within the scope of this study, it can be concluded that the masticatory efficiency will be generally higher in patients provided with complete dentures fabricated using the lingualized occlusal scheme.

  15. Multiuser switched diversity scheduling schemes

    KAUST Repository

    Shaqfeh, Mohammad; Alnuweiri, Hussein M.; Alouini, Mohamed-Slim

    2012-01-01

    Multiuser switched-diversity scheduling schemes were recently proposed in order to overcome the heavy feedback requirements of conventional opportunistic scheduling schemes by applying a threshold-based, distributed, and ordered scheduling mechanism. The main idea behind these schemes is that slight reduction in the prospected multiuser diversity gains is an acceptable trade-off for great savings in terms of required channel-state-information feedback messages. In this work, we characterize the achievable rate region of multiuser switched diversity systems and compare it with the rate region of full feedback multiuser diversity systems. We propose also a novel proportional fair multiuser switched-based scheduling scheme and we demonstrate that it can be optimized using a practical and distributed method to obtain the feedback thresholds. We finally demonstrate by numerical examples that switched-diversity scheduling schemes operate within 0.3 bits/sec/Hz from the ultimate network capacity of full feedback systems in Rayleigh fading conditions. © 2012 IEEE.

  16. Nonlinear secret image sharing scheme.

    Science.gov (United States)

    Shin, Sang-Ho; Lee, Gil-Je; Yoo, Kee-Young

    2014-01-01

    Over the past decade, most of secret image sharing schemes have been proposed by using Shamir's technique. It is based on a linear combination polynomial arithmetic. Although Shamir's technique based secret image sharing schemes are efficient and scalable for various environments, there exists a security threat such as Tompa-Woll attack. Renvall and Ding proposed a new secret sharing technique based on nonlinear combination polynomial arithmetic in order to solve this threat. It is hard to apply to the secret image sharing. In this paper, we propose a (t, n)-threshold nonlinear secret image sharing scheme with steganography concept. In order to achieve a suitable and secure secret image sharing scheme, we adapt a modified LSB embedding technique with XOR Boolean algebra operation, define a new variable m, and change a range of prime p in sharing procedure. In order to evaluate efficiency and security of proposed scheme, we use the embedding capacity and PSNR. As a result of it, average value of PSNR and embedding capacity are 44.78 (dB) and 1.74t⌈log2 m⌉ bit-per-pixel (bpp), respectively.

  17. Multiuser switched diversity scheduling schemes

    KAUST Repository

    Shaqfeh, Mohammad

    2012-09-01

    Multiuser switched-diversity scheduling schemes were recently proposed in order to overcome the heavy feedback requirements of conventional opportunistic scheduling schemes by applying a threshold-based, distributed, and ordered scheduling mechanism. The main idea behind these schemes is that slight reduction in the prospected multiuser diversity gains is an acceptable trade-off for great savings in terms of required channel-state-information feedback messages. In this work, we characterize the achievable rate region of multiuser switched diversity systems and compare it with the rate region of full feedback multiuser diversity systems. We propose also a novel proportional fair multiuser switched-based scheduling scheme and we demonstrate that it can be optimized using a practical and distributed method to obtain the feedback thresholds. We finally demonstrate by numerical examples that switched-diversity scheduling schemes operate within 0.3 bits/sec/Hz from the ultimate network capacity of full feedback systems in Rayleigh fading conditions. © 2012 IEEE.

  18. Instructional immediacy in elearning.

    Science.gov (United States)

    Walkem, Kerrie

    2014-01-01

    Instructor immediacy has been positively associated with many desirable academic outcomes including increased student learning. This study extends existing understanding of instructional immediacy behaviours in elearning by describing postgraduate nursing students' reflections on their own experience. An exploratory, descriptive survey design was used to collect qualitative data. Participants were asked what behaviours or activities help to create rapport or a positive interpersonal connection (immediacy) between students and their online teacher(s). Thematic analysis of the data revealed three main themes: acknowledging and affirming student's personal and professional responsibilities; providing clear and timely information; and utilising rich media. These findings give lecturers insight into instructional strategies they may adopt to increase immediacy in elearning and hence improve student learning outcomes.

  19. A Critique of Instructional

    OpenAIRE

    McKernan, James

    2010-01-01

    The ‘objectives model’ of curriculum planning, predicated upon behavioural performances, has become the dominant form of curriculum planning in Europe and elsewhere in the world. This paper argues that the objectives model is satisfactory for training or instruction, but falls down when applied to a true sense of ‘education’. The paper outlines 13 limitations on the use of educational objectives. It is argued that those interested in using objectives are guided by evaluation as assessment rat...

  20. Effective Multicultural Instruction

    Directory of Open Access Journals (Sweden)

    Franklin T. Thompson

    2014-02-01

    Full Text Available The reason why the Trayvon Martin murder trial and similar court cases create a philosophical rift in our nation is due in part to flaws in the delivery of multicultural education. Traditional multicultural instruction does not prepare citizens for the subtleties and complexities of race relations. This study investigates critical strategies and practices that address multicultural missing gaps. I also seek to fill a void in the literature created by a lack of student input regarding teaching strategies that encourage lifelong learning. Students (N = 337 enrolled at a Midwestern university were asked to rate the efficacy of selected instructional strategies. Utilizing a 9-point Likert-type scale, students gave themselves a personal growth rating of 7.15 (SD = 1.47. Variables important to predicting that growth (R2 = .56, p < .0005 were a six-factor variable known as a non-color-blind instructional approach (t = 10.509, p ≤ .0005, allowing students an opportunity to form their own opinions apart from the instructor (t = 4.797, p ≤ .0005, and a state law that mandated multicultural training (t = 3.234, p = .001. Results demonstrated that utilizing a 35% traditional and 65% critical pedagogy mixture when teaching multicultural education helped promote win/win scenarios for education candidates hoping to become difference makers.

  1. Electrical Injection Schemes for Nanolasers

    DEFF Research Database (Denmark)

    Lupi, Alexandra; Chung, Il-Sug; Yvind, Kresten

    2014-01-01

    Three electrical injection schemes based on recently demonstrated electrically pumped photonic crystal nanolasers have been numerically investigated: 1) a vertical p-i-n junction through a post structure; 2) a lateral p-i-n junction with a homostructure; and 3) a lateral p-i-n junction....... For this analysis, the properties of different schemes, i.e., electrical resistance, threshold voltage, threshold current, and internal efficiency as energy requirements for optical interconnects are compared and the physics behind the differences is discussed....

  2. Signal multiplexing scheme for LINAC

    International Nuclear Information System (INIS)

    Sujo, C.I.; Mohan, Shyam; Joshi, Gopal; Singh, S.K.; Karande, Jitendra

    2004-01-01

    For the proper operation of the LINAC some signals, RF (radio frequency) as well as LF (low frequency) have to be available at the Master Control Station (MCS). These signals are needed to control, calibrate and characterize the RF fields in the resonators. This can be achieved by proper multiplexing of various signals locally and then routing the selected signals to the MCS. A multiplexing scheme has been designed and implemented, which will allow the signals from the selected cavity to the MCS. High isolation between channels and low insertion loss for a given signal are important issues while selecting the multiplexing scheme. (author)

  3. Capacity-achieving CPM schemes

    OpenAIRE

    Perotti, Alberto; Tarable, Alberto; Benedetto, Sergio; Montorsi, Guido

    2008-01-01

    The pragmatic approach to coded continuous-phase modulation (CPM) is proposed as a capacity-achieving low-complexity alternative to the serially-concatenated CPM (SC-CPM) coding scheme. In this paper, we first perform a selection of the best spectrally-efficient CPM modulations to be embedded into SC-CPM schemes. Then, we consider the pragmatic capacity (a.k.a. BICM capacity) of CPM modulations and optimize it through a careful design of the mapping between input bits and CPM waveforms. The s...

  4. On 165Ho level scheme

    International Nuclear Information System (INIS)

    Ardisson, Claire; Ardisson, Gerard.

    1976-01-01

    A 165 Ho level scheme was constructed which led to the interpretation of sixty γ rays belonging to the decay of 165 Dy. A new 702.9keV level was identified to be the 5/2 - member of the 1/2 ) 7541{ Nilsson orbit. )] [fr

  5. Homogenization scheme for acoustic metamaterials

    KAUST Repository

    Yang, Min; Ma, Guancong; Wu, Ying; Yang, Zhiyu; Sheng, Ping

    2014-01-01

    the scattering amplitudes. We verify our scheme by applying it to three different examples: a layered lattice, a two-dimensional hexagonal lattice, and a decorated-membrane system. It is shown that the predicted characteristics and wave fields agree almost

  6. Homogenization scheme for acoustic metamaterials

    KAUST Repository

    Yang, Min

    2014-02-26

    We present a homogenization scheme for acoustic metamaterials that is based on reproducing the lowest orders of scattering amplitudes from a finite volume of metamaterials. This approach is noted to differ significantly from that of coherent potential approximation, which is based on adjusting the effective-medium parameters to minimize scatterings in the long-wavelength limit. With the aid of metamaterials’ eigenstates, the effective parameters, such as mass density and elastic modulus can be obtained by matching the surface responses of a metamaterial\\'s structural unit cell with a piece of homogenized material. From the Green\\'s theorem applied to the exterior domain problem, matching the surface responses is noted to be the same as reproducing the scattering amplitudes. We verify our scheme by applying it to three different examples: a layered lattice, a two-dimensional hexagonal lattice, and a decorated-membrane system. It is shown that the predicted characteristics and wave fields agree almost exactly with numerical simulations and experiments and the scheme\\'s validity is constrained by the number of dominant surface multipoles instead of the usual long-wavelength assumption. In particular, the validity extends to the full band in one dimension and to regimes near the boundaries of the Brillouin zone in two dimensions.

  7. New practicable Siberian Snake schemes

    International Nuclear Information System (INIS)

    Steffen, K.

    1983-07-01

    Siberian Snake schemes can be inserted in ring accelerators for making the spin tune almost independent of energy. Two such schemes are here suggested which lend particularly well to practical application over a wide energy range. Being composed of horizontal and vertical bending magnets, the proposed snakes are designed to have a small maximum beam excursion in one plane. By applying in this plane a bending correction that varies with energy, they can be operated at fixed geometry in the other plane where most of the bending occurs, thus avoiding complicated magnet motion or excessively large magnet apertures that would otherwise be needed for large energy variations. The first of the proposed schemes employs a pair of standard-type Siberian Snakes, i.e. of the usual 1st and 2nd kind which rotate the spin about the longitudinal and the transverse horizontal axis, respectively. The second scheme employs a pair of novel-type snakes which rotate the spin about either one of the horizontal axes that are at 45 0 to the beam direction. In obvious reference to these axes, they are called left-pointed and right-pointed snakes. (orig.)

  8. Nonlinear Secret Image Sharing Scheme

    Directory of Open Access Journals (Sweden)

    Sang-Ho Shin

    2014-01-01

    efficiency and security of proposed scheme, we use the embedding capacity and PSNR. As a result of it, average value of PSNR and embedding capacity are 44.78 (dB and 1.74tlog2⁡m bit-per-pixel (bpp, respectively.

  9. USING GOOGLE+ FOR INSTRUCTION

    Directory of Open Access Journals (Sweden)

    Kevin YEE

    Full Text Available Introduced in July, 2011 in a beta test of invited users only, the new social media service Google+ (or G+ quickly spread by word of mouth, and Google leader Larry Page (2011 blogged that within sixteen days it had 10 million users. By August, it had 25 million users (Cashmore, 2011. Even with slower growth ahead (still with no marketing budget, the service looks likely to crest 100 million users perhaps as early as ten months, a feat that took Facebook three years. Other social networks, most notably Facebook and Twitter, have been used increasingly as instructional tools, since they are platforms with which students are already familiar (Maloney, 2007; McLoughlin & Lee, 2007. Selwyn (2009 found that students often eschew official channels for communication in favor of less formal community-based formats such as Facebook, implying a growing need for instructional communication tools that will be used willingly by students. The question is whether Google+ can be used like Twitter or Facebook to augment instruction, or even, perhaps, to improve upon those predecessors for academic purposes. Google+ is like Twitter in that anyone can follow a given user’s posts. There is no direct “friend” relationship required to read the posts written by others. However, it also approximates some features of Facebook. Rather than friends sorted into “lists” like in Facebook, Google+ allows users to place feeds into one or more “circles,” the better to monitor (or control the flow of information to and from different audiences. Circles are more intuitive, and more central to the experience, than the Facebook lists. They provide an explicit organizational structure, compared to the less-obvious listing functionality, which feels like an afterthought, found in Facebook.

  10. EST Vocabulary Instruction

    Directory of Open Access Journals (Sweden)

    Célia D.S. Bell

    2012-05-01

    Full Text Available This study aims at contributing to the investigation on the instruction of EST (English for Science and Technology vocabulary, in terms of receptive use of the language. It evaluates the effectiveness of two teaching approaches to the acquisition of vocabulary. The first approach consisted of teaching vocabulary through the use of dictionaries, where the words were merely translated into the learners’ L1 or defined in the target language thus promoting superficial level of word processing. The second approach employed activities promoting deep level of word processing. Data were analysed quantitatively. Results indicated that the two approaches seem to have some equipotentiality, as far as EST vocabulary is concerned.

  11. The Mere Exposure Instruction Effect.

    Science.gov (United States)

    Van Dessel, Pieter; Mertens, Gaëtan; Smith, Colin Tucker; De Houwer, Jan

    2017-09-01

    The mere exposure effect refers to the well-established finding that people evaluate a stimulus more positively after repeated exposure to that stimulus. We investigated whether a change in stimulus evaluation can occur also when participants are not repeatedly exposed to a stimulus, but are merely instructed that one stimulus will occur frequently and another stimulus will occur infrequently. We report seven experiments showing that (1) mere exposure instructions influence implicit stimulus evaluations as measured with an Implicit Association Test (IAT), personalized Implicit Association Test (pIAT), or Affect Misattribution Procedure (AMP), but not with an Evaluative Priming Task (EPT), (2) mere exposure instructions influence explicit evaluations, and (3) the instruction effect depends on participants' memory of which stimulus will be presented more frequently. We discuss how these findings inform us about the boundary conditions of mere exposure instruction effects, as well as the mental processes that underlie mere exposure and mere exposure instruction effects.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. The Instructional Network: Using Facebook to Enhance Undergraduate Mathematics Instruction

    Science.gov (United States)

    Gregory, Peter; Gregory, Karen; Eddy, Erik

    2014-01-01

    Facebook is a website with over one billion users worldwide that is synonymous with social-networking. However, in this study, Facebook is used as an "instructional network". Two sections of an undergraduate calculus course were used to study the effects of participating in a Facebook group devoted solely to instruction. One section was…

  17. Improving Reading Instruction through Research-Based Instructional Strategies

    Science.gov (United States)

    Nash, Vickie Lynn

    2010-01-01

    The diverse population of students in grades 1- 3 at a suburban elementary school has created a challenge for teachers when differentiating instruction in reading. The purpose of this doctoral project study was to explore the lived experiences of these teachers as they have acquired research-based instructional strategies in reading that support…

  18. Support Schemes and Ownership Structures

    DEFF Research Database (Denmark)

    Ropenus, Stephanie; Schröder, Sascha Thorsten; Costa, Ana

    , Denmark, France and Portugal. Another crucial aspect for the diffusion of the mCHP technology is possible ownership structures. These may range from full consumer ownership to ownership by utilities and energy service companies, which is discussed in Section 6. Finally, a conclusion (Section 7) wraps up......In recent years, fuel cell based micro‐combined heat and power has received increasing attention due to its potential contribution to energy savings, efficiency gains, customer proximity and flexibility in operation and capacity size. The FC4Home project assesses technical and economic aspects...... of support scheme simultaneously affects risk and technological development, which is the focus of Section 4. Subsequent to this conceptual overview, Section 5 takes a glance at the national application of support schemes for mCHP in practice, notably in the three country cases of the FC4Home project...

  19. [PICS: pharmaceutical inspection cooperation scheme].

    Science.gov (United States)

    Morénas, J

    2009-01-01

    The pharmaceutical inspection cooperation scheme (PICS) is a structure containing 34 participating authorities located worldwide (October 2008). It has been created in 1995 on the basis of the pharmaceutical inspection convention (PIC) settled by the European free trade association (EFTA) in1970. This scheme has different goals as to be an international recognised body in the field of good manufacturing practices (GMP), for training inspectors (by the way of an annual seminar and experts circles related notably to active pharmaceutical ingredients [API], quality risk management, computerized systems, useful for the writing of inspection's aide-memoires). PICS is also leading to high standards for GMP inspectorates (through regular crossed audits) and being a room for exchanges on technical matters between inspectors but also between inspectors and pharmaceutical industry.

  20. Project financing renewable energy schemes

    International Nuclear Information System (INIS)

    Brandler, A.

    1993-01-01

    The viability of many Renewable Energy projects is critically dependent upon the ability of these projects to secure the necessary financing on acceptable terms. The principal objective of the study was to provide an overview to project developers of project financing techniques and the conditions under which project finance for Renewable Energy schemes could be raised, focussing on the potential sources of finance, the typical project financing structures that could be utilised for Renewable Energy schemes and the risk/return and security requirements of lenders, investors and other potential sources of financing. A second objective is to describe the appropriate strategy and tactics for developers to adopt in approaching the financing markets for such projects. (author)

  1. Network Regulation and Support Schemes

    DEFF Research Database (Denmark)

    Ropenus, Stephanie; Schröder, Sascha Thorsten; Jacobsen, Henrik

    2009-01-01

    -in tariffs to market-based quota systems, and network regulation approaches, comprising rate-of-return and incentive regulation. National regulation and the vertical structure of the electricity sector shape the incentives of market agents, notably of distributed generators and network operators......At present, there exists no explicit European policy framework on distributed generation. Various Directives encompass distributed generation; inherently, their implementation is to the discretion of the Member States. The latter have adopted different kinds of support schemes, ranging from feed....... This article seeks to investigate the interactions between the policy dimensions of support schemes and network regulation and how they affect the deployment of distributed generation. Firstly, a conceptual analysis examines how the incentives of the different market agents are affected. In particular...

  2. Distance labeling schemes for trees

    DEFF Research Database (Denmark)

    Alstrup, Stephen; Gørtz, Inge Li; Bistrup Halvorsen, Esben

    2016-01-01

    We consider distance labeling schemes for trees: given a tree with n nodes, label the nodes with binary strings such that, given the labels of any two nodes, one can determine, by looking only at the labels, the distance in the tree between the two nodes. A lower bound by Gavoille et al. [Gavoille...... variants such as, for example, small distances in trees [Alstrup et al., SODA, 2003]. We improve the known upper and lower bounds of exact distance labeling by showing that 1/4 log2(n) bits are needed and that 1/2 log2(n) bits are sufficient. We also give (1 + ε)-stretch labeling schemes using Theta...

  3. Small-scale classification schemes

    DEFF Research Database (Denmark)

    Hertzum, Morten

    2004-01-01

    Small-scale classification schemes are used extensively in the coordination of cooperative work. This study investigates the creation and use of a classification scheme for handling the system requirements during the redevelopment of a nation-wide information system. This requirements...... classification inherited a lot of its structure from the existing system and rendered requirements that transcended the framework laid out by the existing system almost invisible. As a result, the requirements classification became a defining element of the requirements-engineering process, though its main...... effects remained largely implicit. The requirements classification contributed to constraining the requirements-engineering process by supporting the software engineers in maintaining some level of control over the process. This way, the requirements classification provided the software engineers...

  4. Cambridge community Optometry Glaucoma Scheme.

    Science.gov (United States)

    Keenan, Jonathan; Shahid, Humma; Bourne, Rupert R; White, Andrew J; Martin, Keith R

    2015-04-01

    With a higher life expectancy, there is an increased demand for hospital glaucoma services in the United Kingdom. The Cambridge community Optometry Glaucoma Scheme (COGS) was initiated in 2010, where new referrals for suspected glaucoma are evaluated by community optometrists with a special interest in glaucoma, with virtual electronic review and validation by a consultant ophthalmologist with special interest in glaucoma. 1733 patients were evaluated by this scheme between 2010 and 2013. Clinical assessment is performed by the optometrist at a remote site. Goldmann applanation tonometry, pachymetry, monoscopic colour optic disc photographs and automated Humphrey visual field testing are performed. A clinical decision is made as to whether a patient has glaucoma or is a suspect, and referred on or discharged as a false positive referral. The clinical findings, optic disc photographs and visual field test results are transmitted electronically for virtual review by a consultant ophthalmologist. The number of false positive referrals from initial referral into the scheme. Of the patients, 46.6% were discharged at assessment and a further 5.7% were discharged following virtual review. Of the patients initially discharged, 2.8% were recalled following virtual review. Following assessment at the hospital, a further 10.5% were discharged after a single visit. The COGS community-based glaucoma screening programme is a safe and effective way of evaluating glaucoma referrals in the community and reducing false-positive referrals for glaucoma into the hospital system. © 2014 Royal Australian and New Zealand College of Ophthalmologists.

  5. New schemes for particle accelerators

    International Nuclear Information System (INIS)

    Nishida, Y.

    1985-01-01

    In the present paper, the authors propose new schemes for realizing the v/sub p/xB accelerator, by using no plasma system for producing the strong longitudinal waves. The first method is to use a grating for obtaining extended interaction of an electron beam moving along the grating surface with light beam incident also along the surface. Here, the light beam propagates obliquely to the grating grooves for producing strong electric field, and the electron beam propagates in parallel to the light beam. The static magnetic field is applied perpendicularly to the grating surface. In the present system, the beam interacts synchronously with the p-polarized wave which has the electric field be parallel to the grating surface. Another conventional scheme is to use a delay circuit. Here, the light beam propagates obliquely between a pair of array of conductor fins or slots. The phase velocity of the spatial harmonics in the y-direction (right angle to the array of slots) is slower than the speed of light. With the aid of powerful laser light or microwave source, it should be possible to miniaturise linacs by using the v/sub p/xB effect and schemes proposed here

  6. A Memory Efficient Network Encryption Scheme

    Science.gov (United States)

    El-Fotouh, Mohamed Abo; Diepold, Klaus

    In this paper, we studied the two widely used encryption schemes in network applications. Shortcomings have been found in both schemes, as these schemes consume either more memory to gain high throughput or low memory with low throughput. The need has aroused for a scheme that has low memory requirements and in the same time possesses high speed, as the number of the internet users increases each day. We used the SSM model [1], to construct an encryption scheme based on the AES. The proposed scheme possesses high throughput together with low memory requirements.

  7. An Arbitrated Quantum Signature Scheme without Entanglement*

    International Nuclear Information System (INIS)

    Li Hui-Ran; Luo Ming-Xing; Peng Dai-Yuan; Wang Xiao-Jun

    2017-01-01

    Several quantum signature schemes are recently proposed to realize secure signatures of quantum or classical messages. Arbitrated quantum signature as one nontrivial scheme has attracted great interests because of its usefulness and efficiency. Unfortunately, previous schemes cannot against Trojan horse attack and DoS attack and lack of the unforgeability and the non-repudiation. In this paper, we propose an improved arbitrated quantum signature to address these secure issues with the honesty arbitrator. Our scheme takes use of qubit states not entanglements. More importantly, the qubit scheme can achieve the unforgeability and the non-repudiation. Our scheme is also secure for other known quantum attacks . (paper)

  8. Security analysis of boolean algebra based on Zhang-Wang digital signature scheme

    International Nuclear Information System (INIS)

    Zheng, Jinbin

    2014-01-01

    In 2005, Zhang and Wang proposed an improvement signature scheme without using one-way hash function and message redundancy. In this paper, we show that this scheme exits potential safety concerns through the analysis of boolean algebra, such as bitwise exclusive-or, and point out that mapping is not one to one between assembly instructions and machine code actually by means of the analysis of the result of the assembly program segment, and which possibly causes safety problems unknown to the software

  9. Security analysis of boolean algebra based on Zhang-Wang digital signature scheme

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Jinbin, E-mail: jbzheng518@163.com [School of Mathematics and Computer Science, Long Yan University, Longyan 364012 (China)

    2014-10-06

    In 2005, Zhang and Wang proposed an improvement signature scheme without using one-way hash function and message redundancy. In this paper, we show that this scheme exits potential safety concerns through the analysis of boolean algebra, such as bitwise exclusive-or, and point out that mapping is not one to one between assembly instructions and machine code actually by means of the analysis of the result of the assembly program segment, and which possibly causes safety problems unknown to the software.

  10. BASIC Instructional Program: System Documentation.

    Science.gov (United States)

    Dageforde, Mary L.

    This report documents the BASIC Instructional Program (BIP), a "hands-on laboratory" that teaches elementary programming in the BASIC language, as implemented in the MAINSAIL language, a machine-independent revision of SAIL which should facilitate implementation of BIP on other computing systems. Eight instructional modules which make up…

  11. Designing Instructional Materials: Some Guidelines.

    Science.gov (United States)

    Burbank, Lucille; Pett, Dennis

    Guidelines for the design of instructional materials are outlined in this paper. The principles of design are presented in five major categories: (1) general design (structural appeal and personal appeal); (2) instructional design (attention, memory, concept learning, and attitude change); (3) visual design (media considerations, pictures, graphs…

  12. Cognitive Approaches to Automated Instruction.

    Science.gov (United States)

    Regian, J. Wesley, Ed.; Shute, Valerie J., Ed.

    This book contains a snapshot of state-of-the-art research on the design of automated instructional systems. Selected cognitive psychologists were asked to describe their approach to instruction and cognitive diagnosis, the theoretical basis of the approach, its utility and applicability, and the knowledge engineering or task analysis methods…

  13. Physics Instruction for Radiologic Technologists

    Science.gov (United States)

    Chaney, Edward L.; And Others

    1974-01-01

    Discusses the Denver collaborative training program in radiologic technology with emphasis upon identification of core topics, preparation of quality instructional materials, and use of innovative teaching techniques, such as computer-assisted instruction and video tape presentations. Included is a 10-week course outline. (CC)

  14. Active Learning through Online Instruction

    Science.gov (United States)

    Gulbahar, Yasemin; Kalelioglu, Filiz

    2010-01-01

    This article explores the use of proper instructional techniques in online discussions that lead to meaningful learning. The research study looks at the effective use of two instructional techniques within online environments, based on qualitative measures. "Brainstorming" and "Six Thinking Hats" were selected and implemented…

  15. Adaptive instruction and pupil achievement

    NARCIS (Netherlands)

    Houtveen, A.A M; Booy, N; de Jong, Robert (Rob); van de Grift, W.J C M

    In this article the results are reported of a quasi-experiment on effects of adaptive instruction on reading results of children in the first year of reading instruction in Dutch primary schools. The research involved 456 pupils from 23 schools (12 experimental and 11 control group schools).

  16. Instructional Theory for Teaching Statistics.

    Science.gov (United States)

    Atwood, Jan R.; Dinham, Sarah M.

    Metatheoretical analysis of Ausubel's Theory of Meaningful Verbal Learning and Gagne's Theory of Instruction using the Dickoff and James paradigm produced two instructional systems for basic statistics. The systems were tested with a pretest-posttest control group design utilizing students enrolled in an introductory-level graduate statistics…

  17. Unaligned instruction relocation

    Energy Technology Data Exchange (ETDEWEB)

    Bertolli, Carlo; O' Brien, John K.; Sallenave, Olivier H.; Sura, Zehra N.

    2017-10-17

    In one embodiment, a computer-implemented method includes receiving source code to be compiled into an executable file for an unaligned instruction set architecture (ISA). Aligned assembled code is generated, by a computer processor. The aligned assembled code complies with an aligned ISA and includes aligned processor code for a processor and aligned accelerator code for an accelerator. A first linking pass is performed on the aligned assembled code, including relocating a first relocation target in the aligned accelerator code that refers to a first object outside the aligned accelerator code. Unaligned assembled code is generated in accordance with the unaligned ISA and includes unaligned accelerator code for the accelerator and unaligned processor code for the processor. A second linking pass is performed on the unaligned assembled code, including relocating a second relocation target outside the unaligned accelerator code that refers to an object in the unaligned accelerator code.

  18. Unaligned instruction relocation

    Science.gov (United States)

    Bertolli, Carlo; O'Brien, John K.; Sallenave, Olivier H.; Sura, Zehra N.

    2018-01-23

    In one embodiment, a computer-implemented method includes receiving source code to be compiled into an executable file for an unaligned instruction set architecture (ISA). Aligned assembled code is generated, by a computer processor. The aligned assembled code complies with an aligned ISA and includes aligned processor code for a processor and aligned accelerator code for an accelerator. A first linking pass is performed on the aligned assembled code, including relocating a first relocation target in the aligned accelerator code that refers to a first object outside the aligned accelerator code. Unaligned assembled code is generated in accordance with the unaligned ISA and includes unaligned accelerator code for the accelerator and unaligned processor code for the processor. A second linking pass is performed on the unaligned assembled code, including relocating a second relocation target outside the unaligned accelerator code that refers to an object in the unaligned accelerator code.

  19. Interactive Instruction in Bayesian Inference

    DEFF Research Database (Denmark)

    Khan, Azam; Breslav, Simon; Hornbæk, Kasper

    2018-01-01

    An instructional approach is presented to improve human performance in solving Bayesian inference problems. Starting from the original text of the classic Mammography Problem, the textual expression is modified and visualizations are added according to Mayer’s principles of instruction. These pri......An instructional approach is presented to improve human performance in solving Bayesian inference problems. Starting from the original text of the classic Mammography Problem, the textual expression is modified and visualizations are added according to Mayer’s principles of instruction....... These principles concern coherence, personalization, signaling, segmenting, multimedia, spatial contiguity, and pretraining. Principles of self-explanation and interactivity are also applied. Four experiments on the Mammography Problem showed that these principles help participants answer the questions...... that an instructional approach to improving human performance in Bayesian inference is a promising direction....

  20. Decoupling schemes for the SSC Collider

    International Nuclear Information System (INIS)

    Cai, Y.; Bourianoff, G.; Cole, B.; Meinke, R.; Peterson, J.; Pilat, F.; Stampke, S.; Syphers, M.; Talman, R.

    1993-05-01

    A decoupling system is designed for the SSC Collider. This system can accommodate three decoupling schemes by using 44 skew quadrupoles in the different configurations. Several decoupling schemes are studied and compared in this paper

  1. Renormalization scheme-invariant perturbation theory

    International Nuclear Information System (INIS)

    Dhar, A.

    1983-01-01

    A complete solution to the problem of the renormalization scheme dependence of perturbative approximants to physical quantities is presented. An equation is derived which determines any physical quantity implicitly as a function of only scheme independent variables. (orig.)

  2. Wireless Broadband Access and Accounting Schemes

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In this paper, we propose two wireless broadband access and accounting schemes. In both schemes, the accounting system adopts RADIUS protocol, but the access system adopts SSH and SSL protocols respectively.

  3. ARS-Media for excel instruction manual

    Science.gov (United States)

    ARS-Media for Excel Instruction Manual is the instruction manual that explains how to use the Excel spreadsheet ARS-Media for Excel application. ARS-Media for Excel Instruction Manual is provided as a pdf file....

  4. Tightly Secure Signatures From Lossy Identification Schemes

    OpenAIRE

    Abdalla , Michel; Fouque , Pierre-Alain; Lyubashevsky , Vadim; Tibouchi , Mehdi

    2015-01-01

    International audience; In this paper, we present three digital signature schemes with tight security reductions in the random oracle model. Our first signature scheme is a particularly efficient version of the short exponent discrete log-based scheme of Girault et al. (J Cryptol 19(4):463–487, 2006). Our scheme has a tight reduction to the decisional short discrete logarithm problem, while still maintaining the non-tight reduction to the computational version of the problem upon which the or...

  5. Comparative study of numerical schemes of TVD3, UNO3-ACM and optimized compact scheme

    Science.gov (United States)

    Lee, Duck-Joo; Hwang, Chang-Jeon; Ko, Duck-Kon; Kim, Jae-Wook

    1995-01-01

    Three different schemes are employed to solve the benchmark problem. The first one is a conventional TVD-MUSCL (Monotone Upwind Schemes for Conservation Laws) scheme. The second scheme is a UNO3-ACM (Uniformly Non-Oscillatory Artificial Compression Method) scheme. The third scheme is an optimized compact finite difference scheme modified by us: the 4th order Runge Kutta time stepping, the 4th order pentadiagonal compact spatial discretization with the maximum resolution characteristics. The problems of category 1 are solved by using the second (UNO3-ACM) and third (Optimized Compact) schemes. The problems of category 2 are solved by using the first (TVD3) and second (UNO3-ACM) schemes. The problem of category 5 is solved by using the first (TVD3) scheme. It can be concluded from the present calculations that the Optimized Compact scheme and the UN03-ACM show good resolutions for category 1 and category 2 respectively.

  6. Optimal Sales Schemes for Network Goods

    DEFF Research Database (Denmark)

    Parakhonyak, Alexei; Vikander, Nick

    consumers simultaneously, serve them all sequentially, or employ any intermediate scheme. We show that the optimal sales scheme is purely sequential, where each consumer observes all previous sales before choosing whether to buy himself. A sequential scheme maximizes the amount of information available...

  7. THROUGHPUT ANALYSIS OF EXTENDED ARQ SCHEMES

    African Journals Online (AJOL)

    PUBLICATIONS1

    ABSTRACT. Various Automatic Repeat Request (ARQ) schemes have been used to combat errors that befall in- formation transmitted in digital communication systems. Such schemes include simple ARQ, mixed mode ARQ and Hybrid ARQ (HARQ). In this study we introduce extended ARQ schemes and derive.

  8. Arbitrated quantum signature scheme with message recovery

    International Nuclear Information System (INIS)

    Lee, Hwayean; Hong, Changho; Kim, Hyunsang; Lim, Jongin; Yang, Hyung Jin

    2004-01-01

    Two quantum signature schemes with message recovery relying on the availability of an arbitrator are proposed. One scheme uses a public board and the other does not. However both schemes provide confidentiality of the message and a higher efficiency in transmission

  9. 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.

  10. REMINDER: Saved Leave Scheme (SLS)

    CERN Multimedia

    2003-01-01

    Transfer of leave to saved leave accounts Under the provisions of the voluntary saved leave scheme (SLS), a maximum total of 10 days'* annual and compensatory leave (excluding saved leave accumulated in accordance with the provisions of Administrative Circular No 22B) can be transferred to the saved leave account at the end of the leave year (30 September). We remind you that unused leave of all those taking part in the saved leave scheme at the closure of the leave year accounts is transferred automatically to the saved leave account on that date. Therefore, staff members have no administrative steps to take. In addition, the transfer, which eliminates the risk of omitting to request leave transfers and rules out calculation errors in transfer requests, will be clearly shown in the list of leave transactions that can be consulted in EDH from October 2003 onwards. Furthermore, this automatic leave transfer optimizes staff members' chances of benefiting from a saved leave bonus provided that they ar...

  11. Quantum Secure Communication Scheme with W State

    International Nuclear Information System (INIS)

    Wang Jian; Zhang Quan; Tang Chaojng

    2007-01-01

    We present a quantum secure communication scheme using three-qubit W state. It is unnecessary for the present scheme to use alternative measurement or Bell basis measurement. Compared with the quantum secure direct communication scheme proposed by Cao et al. [H.J. Cao and H.S. Song, Chin. Phys. Lett. 23 (2006) 290], in our scheme, the detection probability for an eavesdropper's attack increases from 8.3% to 25%. We also show that our scheme is secure for a noise quantum channel.

  12. Labeling schemes for bounded degree graphs

    DEFF Research Database (Denmark)

    Adjiashvili, David; Rotbart, Noy Galil

    2014-01-01

    We investigate adjacency labeling schemes for graphs of bounded degree Δ = O(1). In particular, we present an optimal (up to an additive constant) log n + O(1) adjacency labeling scheme for bounded degree trees. The latter scheme is derived from a labeling scheme for bounded degree outerplanar...... graphs. Our results complement a similar bound recently obtained for bounded depth trees [Fraigniaud and Korman, SODA 2010], and may provide new insights for closing the long standing gap for adjacency in trees [Alstrup and Rauhe, FOCS 2002]. We also provide improved labeling schemes for bounded degree...

  13. Instructed officers Radiation Protection

    International Nuclear Information System (INIS)

    2007-01-01

    This law contains instructions on the prevention of radiological and contains 4 articles Article I: describe the responsibilities of the institutions that operate within the scope of radiological protection in terms of the number of radiation protection officers and personal Supervisors who available in the practices radiation field. Article II: talking about the conditions of radiation protection officers that must be available in the main officers and working field in larg institutions and thecondition of specific requirements for large enterprises of work permits in the field of radiological work that issued by the Council. Article III: the functions and duties of officers in the prevention of radiological oversee the development of radiation protection programmes in the planning stages, construction and preparing the rules of local labour and what it lead of such tasks.Article IV: radiation protection officers powers: to modify and approve the programme of prevention and radiation safety at the company, stop any unsafe steps, amend the steps of the usage, operation of materials, devices and so on

  14. 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.

  15. Telidon Videotex presentation level protocol: Augmented picture description instructions

    Science.gov (United States)

    Obrien, C. D.; Brown, H. G.; Smirle, J. C.; Lum, Y. F.; Kukulka, J. Z.; Kwan, A.

    1982-02-01

    The Telidon Videotex system is a method by which graphic and textual information and transactional services can be accessed from information sources by the general public. In order to transmit information to a Telidon terminal at a minimum bandwidth, and in a manner independent of the type of communications channel, a coding scheme was devised which permits the encoding of a picture into the geometric drawing elements which compose it. These picture description instructions are an alpha geometric coding model and are based on the primitives of POINT, LINE, ARC, RECTANGLE, POLYGON, and INCREMENT. Text is encoded as (ASCII) characters along with a supplementary table of accents and special characters. A mosaic shape table is included for compatibility. A detailed specification of the coding scheme and a description of the principles which make it independent of communications channel and display hardware are provided.

  16. Motivational Measure of the Instruction Compared: Instruction Based on the ARCS Motivation Theory vs Traditional Instruction in Blended Courses

    Science.gov (United States)

    Colakoglu, Ozgur M.; Akdemir, Omur

    2012-01-01

    The ARCS Motivation Theory was proposed to guide instructional designers and teachers who develop their own instruction to integrate motivational design strategies into the instruction. There is a lack of literature supporting the idea that instruction for blended courses if designed based on the ARCS Motivation Theory provides different…

  17. Zoology by Self-Instruction

    Science.gov (United States)

    Roach, Keith; Hammond, Roger

    1976-01-01

    A historical account is given of how a conventional university first-year undergraduate course in zoology has been replaced by a self-instructional one. Advantages and problems are weighed, and successful student achievement and interest are described. (LBH)

  18. A Fallibilistic Model for Instruction

    Science.gov (United States)

    Dawson, A. J.

    1971-01-01

    Discusses models in inquiry and of instruction based on critical Fallibilistic philosophy, developed by Karl R. Popper, which holds that all knowledge grows by conjecture and refutation. Classroom applications of strategies which result from the model are presented. (JP)

  19. Instructional Style Meets Classroom Design.

    Science.gov (United States)

    Novelli, Joan

    1991-01-01

    Nine elementary teachers explain how they design their classrooms to match and support their instructional styles. The teachers focus on whole language programs, student portfolios, science activity set-ups, technology transformation, learning center strategies, and space utilization. (SM)

  20. Intelligent Tools and Instructional Simulations

    National Research Council Canada - National Science Library

    Murray, William R; Sams, Michelle; Belleville, Michael

    2001-01-01

    This intelligent tools and instructional simulations project was an investigation into the utility of a knowledge-based performance support system to support learning and on-task performance for using...

  1. Measurement control workshop instructional materials

    Energy Technology Data Exchange (ETDEWEB)

    Gibbs, Philip [Brookhaven National Lab. (BNL), Upton, NY (United States); Crawford, Cary [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McGinnis, Brent [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Insolves LLC, Piketon, OH (United States)

    2014-04-01

    A workshop to teach the essential elements of an effective nuclear materials control and accountability (MC&A) programs are outlined, along with the modes of Instruction, and the roles and responsibilities of participants in the workshop.

  2. Measurement Control Workshop Instructional Materials

    International Nuclear Information System (INIS)

    Gibbs, Philip; Crawford, Cary; McGinnis, Brent

    2014-01-01

    A workshop to teach the essential elements of an effective nuclear materials control and accountability (MC&A) programs are outlined, along with the modes of Instruction, and the roles and responsibilities of participants in the workshop.

  3. Adaptive Explicitly Parallel Instruction Computing

    National Research Council Canada - National Science Library

    Talla, Surendranath

    2000-01-01

    .... With in this context, we ask ourselves the following questions. 1. Can application performance be improved if the compiler had the freedom to pick the instruction set on a per application basis? 2...

  4. Rating Instructional Conversations: A Guide

    OpenAIRE

    Rueda, Robert; Goldenberg, Claude; Gallimore, Ronald

    1992-01-01

    The current focus on more effective ways to foster literacy in school-age children, especially language minority students, has led to the development of alternative instructional approaches. One such approach is the instructional conversation (IC), based on early work in the Hawaiian Kamehameha Elementary Education Project (KEEP), on neo-Vygotskian theory, and on recent classroom-based research on reading comprehension. The present report outlines preliminary efforts to operationaliz...

  5. PLE-based instruction concept

    Science.gov (United States)

    Javorcik, Tomas

    2017-11-01

    The paper is aimed at the description of a PLE (Personal Learning Environment)-based teaching model suitable for implementation in the instruction of upper primary school students. The paper describes the individual stages of the model and its use of ICT (Information and Communication Technologies) tools. The Personal Learning Environment is a form of instruction which allows for the meaningful use of information and communication technologies (including mobile technologies) in their entirety.

  6. Tritium control and accountability instructions

    International Nuclear Information System (INIS)

    Wall, W.R.; Cruz, S.L.

    1985-08-01

    This instruction describes the tritium accountability procedures practiced by the Tritium Research Laboratory, at Sandia National Laboratories, Livermore. The accountability procedures are based upon the Sandia National Laboratories, Livermore, Nuclear Materials Operations Manual, SAND83-8036. The Nuclear Materials Operations Manual describes accountability techniques which are in compliance with the Department of Energy 5630 series Orders, Code of Federal Regulations, and Sandia National Laboratories Instructions

  7. Tritium control and accountability instructions

    International Nuclear Information System (INIS)

    Wall, W.R.

    1981-03-01

    This instruction describes the tritium accountability procedures practiced by the Tritium Research Laboratory, Building 968 at Sandia National Laboratories, Livermore. The accountability procedures are based upon the Sandia National Laboratories, Livermore, Nuclear Materials Operations Manual, SAND78-8018. The Nuclear Materials Operations Manual describes accountability techniques which are in compliance with the Department of Energy Manual, Code of Federal Regulations, and Sandia National Laboratories Instructions

  8. Fragment separator momentum compression schemes

    Energy Technology Data Exchange (ETDEWEB)

    Bandura, Laura, E-mail: bandura@anl.gov [Facility for Rare Isotope Beams (FRIB), 1 Cyclotron, East Lansing, MI 48824-1321 (United States); National Superconducting Cyclotron Lab, Michigan State University, 1 Cyclotron, East Lansing, MI 48824-1321 (United States); Erdelyi, Bela [Argonne National Laboratory, Argonne, IL 60439 (United States); Northern Illinois University, DeKalb, IL 60115 (United States); Hausmann, Marc [Facility for Rare Isotope Beams (FRIB), 1 Cyclotron, East Lansing, MI 48824-1321 (United States); Kubo, Toshiyuki [RIKEN Nishina Center, RIKEN, Wako (Japan); Nolen, Jerry [Argonne National Laboratory, Argonne, IL 60439 (United States); Portillo, Mauricio [Facility for Rare Isotope Beams (FRIB), 1 Cyclotron, East Lansing, MI 48824-1321 (United States); Sherrill, Bradley M. [National Superconducting Cyclotron Lab, Michigan State University, 1 Cyclotron, East Lansing, MI 48824-1321 (United States)

    2011-07-21

    We present a scheme to use a fragment separator and profiled energy degraders to transfer longitudinal phase space into transverse phase space while maintaining achromatic beam transport. The first order beam optics theory of the method is presented and the consequent enlargement of the transverse phase space is discussed. An interesting consequence of the technique is that the first order mass resolving power of the system is determined by the first dispersive section up to the energy degrader, independent of whether or not momentum compression is used. The fragment separator at the Facility for Rare Isotope Beams is a specific application of this technique and is described along with simulations by the code COSY INFINITY.

  9. Fragment separator momentum compression schemes

    International Nuclear Information System (INIS)

    Bandura, Laura; Erdelyi, Bela; Hausmann, Marc; Kubo, Toshiyuki; Nolen, Jerry; Portillo, Mauricio; Sherrill, Bradley M.

    2011-01-01

    We present a scheme to use a fragment separator and profiled energy degraders to transfer longitudinal phase space into transverse phase space while maintaining achromatic beam transport. The first order beam optics theory of the method is presented and the consequent enlargement of the transverse phase space is discussed. An interesting consequence of the technique is that the first order mass resolving power of the system is determined by the first dispersive section up to the energy degrader, independent of whether or not momentum compression is used. The fragment separator at the Facility for Rare Isotope Beams is a specific application of this technique and is described along with simulations by the code COSY INFINITY.

  10. Electrical injection schemes for nanolasers

    DEFF Research Database (Denmark)

    Lupi, Alexandra; Chung, Il-Sug; Yvind, Kresten

    2013-01-01

    The performance of injection schemes among recently demonstrated electrically pumped photonic crystal nanolasers has been investigated numerically. The computation has been carried out at room temperature using a commercial semiconductor simulation software. For the simulations two electrical...... of 3 InGaAsP QWs on an InP substrate has been chosen for the modeling. In the simulations the main focus is on the electrical and optical properties of the nanolasers i.e. electrical resistance, threshold voltage, threshold current and wallplug efficiency. In the current flow evaluation the lowest...... threshold current has been achieved with the lateral electrical injection through the BH; while the lowest resistance has been obtained from the current post structure even though this model shows a higher current threshold because of the lack of carrier confinement. Final scope of the simulations...

  11. Scheme of thinking quantum systems

    International Nuclear Information System (INIS)

    Yukalov, V I; Sornette, D

    2009-01-01

    A general approach describing quantum decision procedures is developed. The approach can be applied to quantum information processing, quantum computing, creation of artificial quantum intelligence, as well as to analyzing decision processes of human decision makers. Our basic point is to consider an active quantum system possessing its own strategic state. Processing information by such a system is analogous to the cognitive processes associated to decision making by humans. The algebra of probability operators, associated with the possible options available to the decision maker, plays the role of the algebra of observables in quantum theory of measurements. A scheme is advanced for a practical realization of decision procedures by thinking quantum systems. Such thinking quantum systems can be realized by using spin lattices, systems of magnetic molecules, cold atoms trapped in optical lattices, ensembles of quantum dots, or multilevel atomic systems interacting with electromagnetic field

  12. Yellow light for green scheme

    International Nuclear Information System (INIS)

    Morch, Stein

    2004-01-01

    The article asserts that there could be an investment boom for wind, hydro and bio power in a common Norwegian-Swedish market scheme for green certificates. The Swedish authorities are ready, and the Norwegian government is preparing a report to the Norwegian Parliament. What are the ambitions of Norway, and will hydro power be included? A green certificate market common to more countries have never before been established and requires the solution of many challenging problems. In Sweden, certificate support is expected to promote primarily bioenergy, wind power and small-scale hydro power. In Norway there is an evident potential for wind power, and more hydro power can be developed if desired

  13. Pomeranchuk conjecture and symmetry schemes

    Energy Technology Data Exchange (ETDEWEB)

    Galindo, A.; Morales, A.; Ruegg, H. [Junta de Energia Nuclear, Madrid (Spain); European Organization for Nuclear Research, Geneva (Switzerland); University of Geneva, Geneva (Switzerland)

    1963-01-15

    Pomeranchuk has conjectured that the cross-sections for charge-exchange processes vanish asymptotically as the energy tends to infinity. (By ''charge'' it is meant any internal quantum number, like electric charge, hypercharge, .. . ). It has been stated by several people that this conjecture implies equalities among the total cross-sections whenever any symmetry scheme is invoked for the strong interactions. But to our knowledge no explicit general proof of this statement has been given so far. We want to give this proof for any compact Lie group. We also prove, under certain assumptions, that the equality of the total cross-sections implies that s{sup -l} times the charge-exchange forward scattering absorptive amplitudes tend to zero as s -> ∞.

  14. Instructional Technology and Objectification

    Directory of Open Access Journals (Sweden)

    Bekir S. Gur

    2008-05-01

    Full Text Available Objectification refers to the way in which everything (including human beings is treated as an object, raw material, or resource to be manipulated and used. In this article, objectification refers to the way that education is often reduced to the packaging and delivery of information. A critique of objectification in instructional technology is presented. In the context of Heidegger’s critique of technology, the authors claim that objectification in education is metaphysical in the sense that the intelligibility (being of education is equated with ready-to-use packages, and thus is reduced to delivery and transmission of objects. The embodiment dimension of teaching and learning can help us in resisting this reduction. The authors argue that objectification increases bureaucratic control over the teaching process and deskills teachers; and by which teachers are proletarianized. The authors conclude that instructional designers should create structures in which a care relation and dialogue between students and teachers can take place. Résumé: L’objectification réfère à la façon dont tout (incluant les être humains est traité comme un objet, une matière première ou une ressource qui peut être manipulée et utilisée. Dans cet article, l’objectification réfère à la façon dont l’éducation est souvent réduite à la mise en boîte et à la livraison de l’information. Une critique de l’objectification en technologie éducative est présentée. Dans le contexte de la critique de la technologie par Heidegger, les auteurs prétendent que l’objectification en éducation est métaphysique dans le sens que l’intelligibilité (être de l’éducation équivaut à la mise en boîte prêt-à –utiliser, et se résume donc à la livraison et à la transmission d’objets. L’incarnation de l’enseignement et de l’apprentissage peuvent nous aider à résister à cette réduction. Les auteurs arguent que l

  15. Matroids and quantum-secret-sharing schemes

    International Nuclear Information System (INIS)

    Sarvepalli, Pradeep; Raussendorf, Robert

    2010-01-01

    A secret-sharing scheme is a cryptographic protocol to distribute a secret state in an encoded form among a group of players such that only authorized subsets of the players can reconstruct the secret. Classically, efficient secret-sharing schemes have been shown to be induced by matroids. Furthermore, access structures of such schemes can be characterized by an excluded minor relation. No such relations are known for quantum secret-sharing schemes. In this paper we take the first steps toward a matroidal characterization of quantum-secret-sharing schemes. In addition to providing a new perspective on quantum-secret-sharing schemes, this characterization has important benefits. While previous work has shown how to construct quantum-secret-sharing schemes for general access structures, these schemes are not claimed to be efficient. In this context the present results prove to be useful; they enable us to construct efficient quantum-secret-sharing schemes for many general access structures. More precisely, we show that an identically self-dual matroid that is representable over a finite field induces a pure-state quantum-secret-sharing scheme with information rate 1.

  16. Intelligent Instructional Systems in Military Training.

    Science.gov (United States)

    Fletcher, J.D.; Zdybel, Frank

    Intelligent instructional systems can be distinguished from more conventional approaches by the automation of instructional interaction and choice of strategy. This approach promises to reduce the costs of instructional materials preparation and to increase the adaptability and individualization of the instruction delivered. Tutorial simulation…

  17. Compiler-Assisted Multiple Instruction Rollback Recovery Using a Read Buffer. Ph.D. Thesis

    Science.gov (United States)

    Alewine, Neal Jon

    1993-01-01

    Multiple instruction rollback (MIR) is a technique to provide rapid recovery from transient processor failures and was implemented in hardware by researchers and slow in mainframe computers. Hardware-based MIR designs eliminate rollback data hazards by providing data redundancy implemented in hardware. Compiler-based MIR designs were also developed which remove rollback data hazards directly with data flow manipulations, thus eliminating the need for most data redundancy hardware. Compiler-assisted techniques to achieve multiple instruction rollback recovery are addressed. It is observed that data some hazards resulting from instruction rollback can be resolved more efficiently by providing hardware redundancy while others are resolved more efficiently with compiler transformations. A compiler-assisted multiple instruction rollback scheme is developed which combines hardware-implemented data redundancy with compiler-driven hazard removal transformations. Experimental performance evaluations were conducted which indicate improved efficiency over previous hardware-based and compiler-based schemes. Various enhancements to the compiler transformations and to the data redundancy hardware developed for the compiler-assisted MIR scheme are described and evaluated. The final topic deals with the application of compiler-assisted MIR techniques to aid in exception repair and branch repair in a speculative execution architecture.

  18. How can conceptual schemes change teaching?

    Science.gov (United States)

    Wickman, Per-Olof

    2012-03-01

    Lundqvist, Almqvist and Östman describe a teacher's manner of teaching and the possible consequences it may have for students' meaning making. In doing this the article examines a teacher's classroom practice by systematizing the teacher's transactions with the students in terms of certain conceptual schemes, namely the epistemological moves, educational philosophies and the selective traditions of this practice. In connection to their study one may ask how conceptual schemes could change teaching. This article examines how the relationship of the conceptual schemes produced by educational researchers to educational praxis has developed from the middle of the last century to today. The relationship is described as having been transformed in three steps: (1) teacher deficit and social engineering, where conceptual schemes are little acknowledged, (2) reflecting practitioners, where conceptual schemes are mangled through teacher practice to aid the choices of already knowledgeable teachers, and (3) the mangling of the conceptual schemes by researchers through practice with the purpose of revising theory.

  19. Resonance ionization scheme development for europium

    Energy Technology Data Exchange (ETDEWEB)

    Chrysalidis, K., E-mail: katerina.chrysalidis@cern.ch; Goodacre, T. Day; Fedosseev, V. N.; Marsh, B. A. [CERN (Switzerland); Naubereit, P. [Johannes Gutenberg-Universität, Institiut für Physik (Germany); Rothe, S.; Seiffert, C. [CERN (Switzerland); Kron, T.; Wendt, K. [Johannes Gutenberg-Universität, Institiut für Physik (Germany)

    2017-11-15

    Odd-parity autoionizing states of europium have been investigated by resonance ionization spectroscopy via two-step, two-resonance excitations. The aim of this work was to establish ionization schemes specifically suited for europium ion beam production using the ISOLDE Resonance Ionization Laser Ion Source (RILIS). 13 new RILIS-compatible ionization schemes are proposed. The scheme development was the first application of the Photo Ionization Spectroscopy Apparatus (PISA) which has recently been integrated into the RILIS setup.

  20. Secure RAID Schemes for Distributed Storage

    OpenAIRE

    Huang, Wentao; Bruck, Jehoshua

    2016-01-01

    We propose secure RAID, i.e., low-complexity schemes to store information in a distributed manner that is resilient to node failures and resistant to node eavesdropping. We generalize the concept of systematic encoding to secure RAID and show that systematic schemes have significant advantages in the efficiencies of encoding, decoding and random access. For the practical high rate regime, we construct three XOR-based systematic secure RAID schemes with optimal or almost optimal encoding and ...

  1. A new access scheme in OFDMA systems

    Institute of Scientific and Technical Information of China (English)

    GU Xue-lin; YAN Wei; TIAN Hui; ZHANG Ping

    2006-01-01

    This article presents a dynamic random access scheme for orthogonal frequency division multiple access (OFDMA) systems. The key features of the proposed scheme are:it is a combination of both the distributed and the centralized schemes, it can accommodate several delay sensitivity classes,and it can adjust the number of random access channels in a media access control (MAC) frame and the access probability according to the outcome of Mobile Terminals access attempts in previous MAC frames. For floating populated packet-based networks, the proposed scheme possibly leads to high average user satisfaction.

  2. A Spatial Domain Quantum Watermarking Scheme

    International Nuclear Information System (INIS)

    Wei Zhan-Hong; Chen Xiu-Bo; Niu Xin-Xin; Yang Yi-Xian; Xu Shu-Jiang

    2016-01-01

    This paper presents a spatial domain quantum watermarking scheme. For a quantum watermarking scheme, a feasible quantum circuit is a key to achieve it. This paper gives a feasible quantum circuit for the presented scheme. In order to give the quantum circuit, a new quantum multi-control rotation gate, which can be achieved with quantum basic gates, is designed. With this quantum circuit, our scheme can arbitrarily control the embedding position of watermark images on carrier images with the aid of auxiliary qubits. Besides reversely acting the given quantum circuit, the paper gives another watermark extracting algorithm based on quantum measurements. Moreover, this paper also gives a new quantum image scrambling method and its quantum circuit. Differ from other quantum watermarking schemes, all given quantum circuits can be implemented with basic quantum gates. Moreover, the scheme is a spatial domain watermarking scheme, and is not based on any transform algorithm on quantum images. Meanwhile, it can make sure the watermark be secure even though the watermark has been found. With the given quantum circuit, this paper implements simulation experiments for the presented scheme. The experimental result shows that the scheme does well in the visual quality and the embedding capacity. (paper)

  3. Quantum signature scheme for known quantum messages

    International Nuclear Information System (INIS)

    Kim, Taewan; Lee, Hyang-Sook

    2015-01-01

    When we want to sign a quantum message that we create, we can use arbitrated quantum signature schemes which are possible to sign for not only known quantum messages but also unknown quantum messages. However, since the arbitrated quantum signature schemes need the help of a trusted arbitrator in each verification of the signature, it is known that the schemes are not convenient in practical use. If we consider only known quantum messages such as the above situation, there can exist a quantum signature scheme with more efficient structure. In this paper, we present a new quantum signature scheme for known quantum messages without the help of an arbitrator. Differing from arbitrated quantum signature schemes based on the quantum one-time pad with the symmetric key, since our scheme is based on quantum public-key cryptosystems, the validity of the signature can be verified by a receiver without the help of an arbitrator. Moreover, we show that our scheme provides the functions of quantum message integrity, user authentication and non-repudiation of the origin as in digital signature schemes. (paper)

  4. 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...

  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. Anonymous Credential Schemes with Encrypted Attributes

    NARCIS (Netherlands)

    Guajardo Merchan, J.; Mennink, B.; Schoenmakers, B.

    2011-01-01

    In anonymous credential schemes, users obtain credentials on certain attributes from an issuer, and later show these credentials to a relying party anonymously and without fully disclosing the attributes. In this paper, we introduce the notion of (anonymous) credential schemes with encrypted

  7. Community healthcare financing scheme: findings among residents ...

    African Journals Online (AJOL)

    ... none were active participants as 2(0.6%) were indifferent. There was a statistically significant relationship, Fischers <0.0001 between sex and the scheme's knowledge. Conclusion: Knowledge of the scheme was poor among majority of the respondents and none were active participants. Bribery and corruption was the ...

  8. Improved Load Shedding Scheme considering Distributed Generation

    DEFF Research Database (Denmark)

    Das, Kaushik; Nitsas, Antonios; Altin, Müfit

    2017-01-01

    With high penetration of distributed generation (DG), the conventional under-frequency load shedding (UFLS) face many challenges and may not perform as expected. This article proposes new UFLS schemes, which are designed to overcome the shortcomings of traditional load shedding scheme...

  9. A generalized scheme for designing multistable continuous ...

    Indian Academy of Sciences (India)

    In this paper, a generalized scheme is proposed for designing multistable continuous dynamical systems. The scheme is based on the concept of partial synchronization of states and the concept of constants of motion. The most important observation is that by coupling two mdimensional dynamical systems, multistable ...

  10. Consolidation of the health insurance scheme

    CERN Document Server

    Association du personnel

    2009-01-01

    In the last issue of Echo, we highlighted CERN’s obligation to guarantee a social security scheme for all employees, pensioners and their families. In that issue we talked about the first component: pensions. This time we shall discuss the other component: the CERN Health Insurance Scheme (CHIS).

  11. A hierarchical classification scheme of psoriasis images

    DEFF Research Database (Denmark)

    Maletti, Gabriela Mariel; Ersbøll, Bjarne Kjær

    2003-01-01

    A two-stage hierarchical classification scheme of psoriasis lesion images is proposed. These images are basically composed of three classes: normal skin, lesion and background. The scheme combines conventional tools to separate the skin from the background in the first stage, and the lesion from...

  12. Privacy Preserving Mapping Schemes Supporting Comparison

    NARCIS (Netherlands)

    Tang, Qiang

    2010-01-01

    To cater to the privacy requirements in cloud computing, we introduce a new primitive, namely Privacy Preserving Mapping (PPM) schemes supporting comparison. An PPM scheme enables a user to map data items into images in such a way that, with a set of images, any entity can determine the <, =, >

  13. Mixed ultrasoft/norm-conserved pseudopotential scheme

    DEFF Research Database (Denmark)

    Stokbro, Kurt

    1996-01-01

    A variant of the Vanderbilt ultrasoft pseudopotential scheme, where the norm conservation is released for only one or a few angular channels, is presented. Within this scheme some difficulties of the truly ultrasoft pseudopotentials are overcome without sacrificing the pseudopotential softness. (...

  14. Best practices in writing instruction

    CERN Document Server

    Fitzgerald, Jill; MacArthur, Charles A

    2014-01-01

    An indispensable teacher resource and course text, this book presents evidence-based practices for helping all K-12 students develop their skills as writers. Every chapter draws clear connections to the Common Core State Standards (CCSS). Leading authorities describe how to teach the skills and strategies that students need to plan, draft, evaluate, and revise multiple types of texts. Also addressed are ways for teachers to integrate technology into the writing program, use assessment to inform instruction, teach writing in the content areas, and tailor instruction for English language learner

  15. Teaching Critical Questions about Argumentation through the Revising Process: Effects of Strategy Instruction on College Students' Argumentative Essays

    Science.gov (United States)

    Song, Yi; Ferretti, Ralph P.

    2013-01-01

    The effects of self-regulated strategy development revising instruction for college students that targeted the use of argumentation schemes and critical questions were assessed in three conditions. In the first condition, students were taught to revise their essays by asking and answering critical questions about the "argument from consequences"…

  16. Labelling schemes: From a consumer perspective

    DEFF Research Database (Denmark)

    Juhl, Hans Jørn; Stacey, Julia

    2000-01-01

    Labelling of food products attracts a lot of political attention these days. As a result of a number of food scandals, most European countries have acknowledged the need for more information and better protection of consumers. Labelling schemes are one way of informing and guiding consumers....... However, initiatives in relation to labelling schemes seldom take their point of departure in consumers' needs and expectations; and in many cases, the schemes are defined by the institutions guaranteeing the label. It is therefore interesting to study how consumers actually value labelling schemes....... A recent MAPP study has investigated the value consumers attach the Government-controlled labels 'Ø-mærket' and 'Den Blå Lup' and the private supermarket label 'Mesterhakket' when they purchase minced meat. The results reveal four consumer segments that use labelling schemes for food products very...

  17. Birkhoffian Symplectic Scheme for a Quantum System

    International Nuclear Information System (INIS)

    Su Hongling

    2010-01-01

    In this paper, a classical system of ordinary differential equations is built to describe a kind of n-dimensional quantum systems. The absorption spectrum and the density of the states for the system are defined from the points of quantum view and classical view. From the Birkhoffian form of the equations, a Birkhoffian symplectic scheme is derived for solving n-dimensional equations by using the generating function method. Besides the Birkhoffian structure-preserving, the new scheme is proven to preserve the discrete local energy conservation law of the system with zero vector f. Some numerical experiments for a 3-dimensional example show that the new scheme can simulate the general Birkhoffian system better than the implicit midpoint scheme, which is well known to be symplectic scheme for Hamiltonian system. (general)

  18. Autonomous droop scheme with reduced generation cost

    DEFF Research Database (Denmark)

    Nutkani, Inam Ullah; Loh, Poh Chiang; Blaabjerg, Frede

    2013-01-01

    Droop scheme has been widely applied to the control of Distributed Generators (DGs) in microgrids for proportional power sharing based on their ratings. For standalone microgrid, where centralized management system is not viable, the proportional power sharing based droop might not suit well since...... DGs are usually of different types unlike synchronous generators. This paper presents an autonomous droop scheme that takes into consideration the operating cost, efficiency and emission penalty of each DG since all these factors directly or indirectly contributes to the Total Generation Cost (TGC......) of the overall microgrid. Comparing it with the traditional scheme, the proposed scheme has retained its simplicity, which certainly is a feature preferred by the industry. The overall performance of the proposed scheme has been verified through simulation and experiment....

  19. A Fast CT Reconstruction Scheme for a General Multi-Core PC

    Directory of Open Access Journals (Sweden)

    Kai Zeng

    2007-01-01

    Full Text Available Expensive computational cost is a severe limitation in CT reconstruction for clinical applications that need real-time feedback. A primary example is bolus-chasing computed tomography (CT angiography (BCA that we have been developing for the past several years. To accelerate the reconstruction process using the filtered backprojection (FBP method, specialized hardware or graphics cards can be used. However, specialized hardware is expensive and not flexible. The graphics processing unit (GPU in a current graphic card can only reconstruct images in a reduced precision and is not easy to program. In this paper, an acceleration scheme is proposed based on a multi-core PC. In the proposed scheme, several techniques are integrated, including utilization of geometric symmetry, optimization of data structures, single-instruction multiple-data (SIMD processing, multithreaded computation, and an Intel C++ compilier. Our scheme maintains the original precision and involves no data exchange between the GPU and CPU. The merits of our scheme are demonstrated in numerical experiments against the traditional implementation. Our scheme achieves a speedup of about 40, which can be further improved by several folds using the latest quad-core processors.

  20. A fast CT reconstruction scheme for a general multi-core PC.

    Science.gov (United States)

    Zeng, Kai; Bai, Erwei; Wang, Ge

    2007-01-01

    Expensive computational cost is a severe limitation in CT reconstruction for clinical applications that need real-time feedback. A primary example is bolus-chasing computed tomography (CT) angiography (BCA) that we have been developing for the past several years. To accelerate the reconstruction process using the filtered backprojection (FBP) method, specialized hardware or graphics cards can be used. However, specialized hardware is expensive and not flexible. The graphics processing unit (GPU) in a current graphic card can only reconstruct images in a reduced precision and is not easy to program. In this paper, an acceleration scheme is proposed based on a multi-core PC. In the proposed scheme, several techniques are integrated, including utilization of geometric symmetry, optimization of data structures, single-instruction multiple-data (SIMD) processing, multithreaded computation, and an Intel C++ compilier. Our scheme maintains the original precision and involves no data exchange between the GPU and CPU. The merits of our scheme are demonstrated in numerical experiments against the traditional implementation. Our scheme achieves a speedup of about 40, which can be further improved by several folds using the latest quad-core processors.