Work space optimization of a r-r planar manipulator using particle ...

African Journals Online (AJOL)

A two link revolute planar robotic manipulator is optimized for maximization of work space covered by its end effector. A mathematical model for optimization is built considering singularities which control the range of design variables. Condition number which is the measure of change in output value (End effector position) ...

Multi-projector auto-calibration and placement optimization for non-planar surfaces

Science.gov (United States)

Li, Dong; Xie, Jinghui; Zhao, Lu; Zhou, Lijing; Weng, Dongdong

2015-10-01

Non-planar projection has been widely applied in virtual reality and digital entertainment and exhibitions because of its flexible layout and immersive display effects. Compared with planar projection, a non-planar projection is more difficult to achieve because projector calibration and image distortion correction are difficult processes. This paper uses a cylindrical screen as an example to present a new method for automatically calibrating a multi-projector system in a non-planar environment without using 3D reconstruction. This method corrects the geometric calibration error caused by the screen's manufactured imperfections, such as an undulating surface or a slant in the vertical plane. In addition, based on actual projection demand, this paper presents the overall performance evaluation criteria for the multi-projector system. According to these criteria, we determined the optimal placement for the projectors. This method also extends to surfaces that can be parameterized, such as spheres, ellipsoids, and paraboloids, and demonstrates a broad applicability.

On the optimal design of glass grid shells with planar quadrilateral elements

DEFF Research Database (Denmark)

Sassone, Mario; Pugnale, Alberto

2010-01-01

specific geometric rules in the grid generation phase but, when the architectural shape is already defined at the conceptual stage, an optimization procedure can yield to suitable configurations. A Relaxation method based on nodal planarity errors and an evolutionary population based Genetic Algorithm have...... been applied to set of benchmarks, in order to tune parameters and to obtain general information about the solution. the problem and their efficiency compared. The Relaxation method in general shows better efficiency in reaching optimal solutions, as an effect of the regularity of the target function......This paper presents an optimization procedure for the solution of the planarity problem, a requirement of grid shells with four or more sides faces that need of having four adjacent nodes laying on a plane in order to use plane glass slabs as cladding elements. It can be satisfied by applying...

Work space optimization of a r-r planar manipulator using particle ...

African Journals Online (AJOL)

*Corresponding Author (1) E-Mail:chaitanyagoteti16@gmail.com ... presented the variable structure theory for planning and trajectory control of planar ..... Rao S.S., 2009, Engineering Optimization Theory and Practice, 4th edition, Ed., John ...

Guidelines for optimization of planar HDR implants

International Nuclear Information System (INIS)

Zwicker, R.D.; Schmidt-Ullrich, R.

1996-01-01

Purpose: Conventional low dose rate (LDR) planar Ir-192 implants are typically carried out using at most a few different source strengths. Remote afterloading offers a much higher degree of flexibility with individually programmable dwell times. Dedicated software is available to generate individual dwell times producing isodose surfaces which contour as closely as possible the target volume. The success of these algorithms in enclosing the target volume while sparing normal tissues is dependent on the positioning of the source guides which constrain the dwell points. In this work we provide source placement guidelines for optimal coverage and dose uniformity in planar high dose rate (HDR) implants. The resulting distributions are compared with LDR treatments in terms of dose uniformity and early and late tissue effects. Materials and methods: Computer studies were undertaken to determine source positions and dwell times for optimal dose uniformity in planar HDR implants, and the results were compared to those obtained using corresponding LDR implant geometries. The improvements in the dose distributions achieved with the remote after loader are expected to help offset the increased late tissue effects which can occur when LDR irradiation is replaced with a few large HDR fractions. Equivalent differential volume-dose (DVD) curves for early and late effects were calculated for different numbers of HDR fractions using a linear-quadratic model and compared to the corresponding curves for the LDR regime. Results: Tables of source placement parameters were generated as guidelines for achieving highly homogeneous planar HDR dose distributions. Differential volume-dose data generated inside the target volume provide a quantitative measure of the improvement in real dose homogeneity obtained with remote afterloading. The net result is a shift of the peak in the DVD curve toward lower doses relative to the LDR implant. The equivalent DVD curves for late effects obtained

Optimal design of planar slider-crank mechanism using teaching-learning-based optimization algorithm

International Nuclear Information System (INIS)

Chaudhary, Kailash; Chaudhary, Himanshu

2015-01-01

In this paper, a two stage optimization technique is presented for optimum design of planar slider-crank mechanism. The slider crank mechanism needs to be dynamically balanced to reduce vibrations and noise in the engine and to improve the vehicle performance. For dynamic balancing, minimization of the shaking force and the shaking moment is achieved by finding optimum mass distribution of crank and connecting rod using the equipemental system of point-masses in the first stage of the optimization. In the second stage, their shapes are synthesized systematically by closed parametric curve, i.e., cubic B-spline curve corresponding to the optimum inertial parameters found in the first stage. The multi-objective optimization problem to minimize both the shaking force and the shaking moment is solved using Teaching-learning-based optimization algorithm (TLBO) and its computational performance is compared with Genetic algorithm (GA).

Optimal design of planar slider-crank mechanism using teaching-learning-based optimization algorithm

Energy Technology Data Exchange (ETDEWEB)

Chaudhary, Kailash; Chaudhary, Himanshu [Malaviya National Institute of Technology, Jaipur (Malaysia)

2015-11-15

In this paper, a two stage optimization technique is presented for optimum design of planar slider-crank mechanism. The slider crank mechanism needs to be dynamically balanced to reduce vibrations and noise in the engine and to improve the vehicle performance. For dynamic balancing, minimization of the shaking force and the shaking moment is achieved by finding optimum mass distribution of crank and connecting rod using the equipemental system of point-masses in the first stage of the optimization. In the second stage, their shapes are synthesized systematically by closed parametric curve, i.e., cubic B-spline curve corresponding to the optimum inertial parameters found in the first stage. The multi-objective optimization problem to minimize both the shaking force and the shaking moment is solved using Teaching-learning-based optimization algorithm (TLBO) and its computational performance is compared with Genetic algorithm (GA).

Optimization of planar self-collimating photonic crystals.

Science.gov (United States)

Rumpf, Raymond C; Pazos, Javier J

2013-07-01

Self-collimation in photonic crystals has received a lot of attention in the literature, partly due to recent interest in silicon photonics, yet no performance metrics have been proposed. This paper proposes a figure of merit (FOM) for self-collimation and outlines a methodical approach for calculating it. Performance metrics include bandwidth, angular acceptance, strength, and an overall FOM. Two key contributions of this work include the performance metrics and identifying that the optimum frequency for self-collimation is not at the inflection point. The FOM is used to optimize a planar photonic crystal composed of a square array of cylinders. Conclusions are drawn about how the refractive indices and fill fraction of the lattice impact each of the performance metrics. The optimization is demonstrated by simulating two spatially variant self-collimating photonic crystals, where one has a high FOM and the other has a low FOM. This work gives optical designers tremendous insight into how to design and optimize robust self-collimating photonic crystals, which promises many applications in silicon photonics and integrated optics.

Lower Bounds in the Asymmetric External Memory Model

DEFF Research Database (Denmark)

Jacob, Riko; Sitchinava, Nodari

2017-01-01

Motivated by the asymmetric read and write costs of emerging non-volatile memory technologies, we study lower bounds for the problems of sorting, permuting and multiplying a sparse matrix by a dense vector in the asymmetric external memory model (AEM). Given an AEM with internal (symmetric) memory...... of size M, transfers between symmetric and asymmetric memory in blocks of size B and the ratio ω between write and read costs, we show Ω(min (N, ωN/B logω M/B N/B) lower bound for the cost of permuting N input elements. This lower bound also applies to the problem of sorting N elements. This proves...

Effects of internal and external vividness on hippocampal connectivity during memory retrieval.

Science.gov (United States)

Ford, Jaclyn H; Kensinger, Elizabeth A

2016-10-01

Successful memory for an image can be supported by retrieval of one's personal reaction to the image (i.e., internal vividness), as well as retrieval of the specific details of the image itself (i.e., external vividness). Prior research suggests that memory vividness relies on regions within the medial temporal lobe, particularly the hippocampus, but it is unclear whether internal and external vividness are supported by the hippocampus in a similar way. To address this open question, the current study examined hippocampal connectivity associated with enhanced internal and external vividness ratings during retrieval. Participants encoded complex visual images paired with verbal titles. During a scanned retrieval session, they were presented with the titles and asked whether each had been seen with an image during encoding. Following retrieval of each image, participants were asked to rate internal and external vividness. Increased hippocampal activity was associated with higher vividness ratings for both scales, supporting prior evidence implicating the hippocampus in retrieval of memory detail. However, different patterns of hippocampal connectivity related to enhanced external and internal vividness. Further, hippocampal connectivity with medial prefrontal regions was associated with increased ratings of internal vividness, but with decreased ratings of external vividness. These findings suggest that the hippocampus may contribute to increased internal and external vividness via distinct mechanisms and that external and internal vividness of memories should be considered as separable measures. Copyright © 2016 Elsevier Inc. All rights reserved.

Characteristics of the Single-Longitudinal-Mode Planar-Waveguide External Cavity Diode Laser at 1064 nm

Science.gov (United States)

Numata, Kenji; Alalusi, Mazin; Stolpner, Lew; Margaritis, Georgios; Camp, Jordan; Krainak, Michael

2014-01-01

We describe the characteristics of the planar-waveguide external cavity diode laser (PW-ECL). To the best of our knowledge, it is the first butterfly-packaged 1064 nm semiconductor laser that is stable enough to be locked to an external frequency reference. We evaluated its performance from the viewpoint of precision experiments. Using a hyperfine absorption line of iodine, we suppressed its frequency noise by a factor of up to 104 at 10 mHz. The PWECL's compactness and low cost make it a candidate to replace traditional Nd:YAG nonplanar ring oscillators and fiber lasers in applications that require a single longitudinal mode.

Optimization and applications of planar silicon-based photonic crystal devices

DEFF Research Database (Denmark)

Borel, Peter Ingo; Frandsen, Lars Hagedorn; Burgos Leon, Juan

2005-01-01

such as topology optimization. We have also investigated a new device concept for coarse wavelength division de-multiplexing based on planar photonic crystal waveguides. The filtering of the wavelength channels has been realized by shifting the cut-off frequency of the fundamental photonic band gap mode...... in consecutive sections of the waveguide. Preliminary investigations show that this concepts allows coarse de-multiplexing to take place, but that optimization is required in order to reduce cross talk between adjacent channels and to increase the overall transmission. In this work the design, fabrication...

Hybrid computing using a neural network with dynamic external memory.

Science.gov (United States)

Graves, Alex; Wayne, Greg; Reynolds, Malcolm; Harley, Tim; Danihelka, Ivo; Grabska-Barwińska, Agnieszka; Colmenarejo, Sergio Gómez; Grefenstette, Edward; Ramalho, Tiago; Agapiou, John; Badia, Adrià Puigdomènech; Hermann, Karl Moritz; Zwols, Yori; Ostrovski, Georg; Cain, Adam; King, Helen; Summerfield, Christopher; Blunsom, Phil; Kavukcuoglu, Koray; Hassabis, Demis

2016-10-27

Artificial neural networks are remarkably adept at sensory processing, sequence learning and reinforcement learning, but are limited in their ability to represent variables and data structures and to store data over long timescales, owing to the lack of an external memory. Here we introduce a machine learning model called a differentiable neural computer (DNC), which consists of a neural network that can read from and write to an external memory matrix, analogous to the random-access memory in a conventional computer. Like a conventional computer, it can use its memory to represent and manipulate complex data structures, but, like a neural network, it can learn to do so from data. When trained with supervised learning, we demonstrate that a DNC can successfully answer synthetic questions designed to emulate reasoning and inference problems in natural language. We show that it can learn tasks such as finding the shortest path between specified points and inferring the missing links in randomly generated graphs, and then generalize these tasks to specific graphs such as transport networks and family trees. When trained with reinforcement learning, a DNC can complete a moving blocks puzzle in which changing goals are specified by sequences of symbols. Taken together, our results demonstrate that DNCs have the capacity to solve complex, structured tasks that are inaccessible to neural networks without external read-write memory.

Automatic Planning of External Search Engine Optimization

Directory of Open Access Journals (Sweden)

Vita Jasevičiūtė

2015-07-01

Full Text Available This paper describes an investigation of the external search engine optimization (SEO action planning tool, dedicated to automatically extract a small set of most important keywords for each month during whole year period. The keywords in the set are extracted accordingly to external measured parameters, such as average number of searches during the year and for every month individually. Additionally the position of the optimized web site for each keyword is taken into account. The generated optimization plan is similar to the optimization plans prepared manually by the SEO professionals and can be successfully used as a support tool for web site search engine optimization.

Efficient external memory structures for range-aggregate queries

DEFF Research Database (Denmark)

Agarwal, P.K.; Yang, J.; Arge, L.

2013-01-01

We present external memory data structures for efficiently answering range-aggregate queries. The range-aggregate problem is defined as follows: Given a set of weighted points in Rd, compute the aggregate of the weights of the points that lie inside a d-dimensional orthogonal query rectangle. The...

Constructing IGA-suitable planar parameterization from complex CAD boundary by domain partition and global/local optimization

Science.gov (United States)

Xu, Gang; Li, Ming; Mourrain, Bernard; Rabczuk, Timon; Xu, Jinlan; Bordas, Stéphane P. A.

2018-01-01

In this paper, we propose a general framework for constructing IGA-suitable planar B-spline parameterizations from given complex CAD boundaries consisting of a set of B-spline curves. Instead of forming the computational domain by a simple boundary, planar domains with high genus and more complex boundary curves are considered. Firstly, some pre-processing operations including B\\'ezier extraction and subdivision are performed on each boundary curve in order to generate a high-quality planar parameterization; then a robust planar domain partition framework is proposed to construct high-quality patch-meshing results with few singularities from the discrete boundary formed by connecting the end points of the resulting boundary segments. After the topology information generation of quadrilateral decomposition, the optimal placement of interior B\\'ezier curves corresponding to the interior edges of the quadrangulation is constructed by a global optimization method to achieve a patch-partition with high quality. Finally, after the imposition of C1=G1-continuity constraints on the interface of neighboring B\\'ezier patches with respect to each quad in the quadrangulation, the high-quality B\\'ezier patch parameterization is obtained by a C1-constrained local optimization method to achieve uniform and orthogonal iso-parametric structures while keeping the continuity conditions between patches. The efficiency and robustness of the proposed method are demonstrated by several examples which are compared to results obtained by the skeleton-based parameterization approach.

Optimal Foraging in Semantic Memory

Science.gov (United States)

Hills, Thomas T.; Jones, Michael N.; Todd, Peter M.

2012-01-01

Do humans search in memory using dynamic local-to-global search strategies similar to those that animals use to forage between patches in space? If so, do their dynamic memory search policies correspond to optimal foraging strategies seen for spatial foraging? Results from a number of fields suggest these possibilities, including the shared…

Dynamic State Space Partitioning for External Memory Model Checking

DEFF Research Database (Denmark)

Evangelista, Sami; Kristensen, Lars Michael

2009-01-01

We describe a dynamic partitioning scheme usable by model checking techniques that divide the state space into partitions, such as most external memory and distributed model checking algorithms. The goal of the scheme is to reduce the number of transitions that link states belonging to different...

Optimizing memory use in Java applications, garbage collectors

Directory of Open Access Journals (Sweden)

Ştefan PREDA

2016-05-01

Full Text Available Java applications are diverse, depending by use case, exist application that use small amount of memory till application that use huge amount, tens or hundreds of gigabits. Java Virtual Machine is designed to automatically manage memory for applications. Even in this case due diversity of hardware, software that coexist on the same system and applications itself, these automatic decision need to be accompanied by developer or system administrator to triage optimal memory use. After developer big role to write optimum code from memory allocation perspective , optimizing memory use at Java Virtual Machine and application level become in last year's one of the most important task. This is explained in special due increased demand in applications scalability.

Technical errors in planar bone scanning.

Science.gov (United States)

Naddaf, Sleiman Y; Collier, B David; Elgazzar, Abdelhamid H; Khalil, Magdy M

2004-09-01

Optimal technique for planar bone scanning improves image quality, which in turn improves diagnostic efficacy. Because planar bone scanning is one of the most frequently performed nuclear medicine examinations, maintaining high standards for this examination is a daily concern for most nuclear medicine departments. Although some problems such as patient motion are frequently encountered, the degraded images produced by many other deviations from optimal technique are rarely seen in clinical practice and therefore may be difficult to recognize. The objectives of this article are to list optimal techniques for 3-phase and whole-body bone scanning, to describe and illustrate a selection of deviations from these optimal techniques for planar bone scanning, and to explain how to minimize or avoid such technical errors.

Continual and One-Shot Learning Through Neural Networks with Dynamic External Memory

DEFF Research Database (Denmark)

Lüders, Benno; Schläger, Mikkel; Korach, Aleksandra

2017-01-01

it easier to find unused memory location and therefor facilitates the evolution of continual learning networks. Our results suggest that augmenting evolving networks with an external memory component is not only a viable mechanism for adaptive behaviors in neuroevolution but also allows these networks...... a new task is learned. This paper takes a step in overcoming this limitation by building on the recently proposed Evolving Neural Turing Machine (ENTM) approach. In the ENTM, neural networks are augmented with an external memory component that they can write to and read from, which allows them to store...... associations quickly and over long periods of time. The results in this paper demonstrate that the ENTM is able to perform one-shot learning in reinforcement learning tasks without catastrophic forgetting of previously stored associations. Additionally, we introduce a new ENTM default jump mechanism that makes...

Adiabatic Quantum Optimization for Associative Memory Recall

Science.gov (United States)

Seddiqi, Hadayat; Humble, Travis

2014-12-01

Hopfield networks are a variant of associative memory that recall patterns stored in the couplings of an Ising model. Stored memories are conventionally accessed as fixed points in the network dynamics that correspond to energetic minima of the spin state. We show that memories stored in a Hopfield network may also be recalled by energy minimization using adiabatic quantum optimization (AQO). Numerical simulations of the underlying quantum dynamics allow us to quantify AQO recall accuracy with respect to the number of stored memories and noise in the input key. We investigate AQO performance with respect to how memories are stored in the Ising model according to different learning rules. Our results demonstrate that AQO recall accuracy varies strongly with learning rule, a behavior that is attributed to differences in energy landscapes. Consequently, learning rules offer a family of methods for programming adiabatic quantum optimization that we expect to be useful for characterizing AQO performance.

Adiabatic Quantum Optimization for Associative Memory Recall

Directory of Open Access Journals (Sweden)

Hadayat eSeddiqi

2014-12-01

Full Text Available Hopfield networks are a variant of associative memory that recall patterns stored in the couplings of an Ising model. Stored memories are conventionally accessed as fixed points in the network dynamics that correspond to energetic minima of the spin state. We show that memories stored in a Hopfield network may also be recalled by energy minimization using adiabatic quantum optimization (AQO. Numerical simulations of the underlying quantum dynamics allow us to quantify AQO recall accuracy with respect to the number of stored memories and noise in the input key. We investigate AQO performance with respect to how memories are stored in the Ising model according to different learning rules. Our results demonstrate that AQO recall accuracy varies strongly with learning rule, a behavior that is attributed to differences in energy landscapes. Consequently, learning rules offer a family of methods for programming adiabatic quantum optimization that we expect to be useful for characterizing AQO performance.

3D Printed Photoresponsive Devices Based on Shape Memory Composites.

Science.gov (United States)

Yang, Hui; Leow, Wan Ru; Wang, Ting; Wang, Juan; Yu, Jiancan; He, Ke; Qi, Dianpeng; Wan, Changjin; Chen, Xiaodong

2017-09-01

Compared with traditional stimuli-responsive devices with simple planar or tubular geometries, 3D printed stimuli-responsive devices not only intimately meet the requirement of complicated shapes at macrolevel but also satisfy various conformation changes triggered by external stimuli at the microscopic scale. However, their development is limited by the lack of 3D printing functional materials. This paper demonstrates the 3D printing of photoresponsive shape memory devices through combining fused deposition modeling printing technology and photoresponsive shape memory composites based on shape memory polymers and carbon black with high photothermal conversion efficiency. External illumination triggers the shape recovery of 3D printed devices from the temporary shape to the original shape. The effect of materials thickness and light density on the shape memory behavior of 3D printed devices is quantified and calculated. Remarkably, sunlight also triggers the shape memory behavior of these 3D printed devices. This facile printing strategy would provide tremendous opportunities for the design and fabrication of biomimetic smart devices and soft robotics. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Tuning Range Optimization of a Planar Inverted F Antenna for LTE Low Frequency Bands

DEFF Research Database (Denmark)

Barrio, Samantha Caporal Del; Pelosi, Mauro; Franek, Ondrej

2011-01-01

This paper presents a Planar Inverted F Antenna (PIFA) tuned with a fixed capacitor to the low frequency bands supported by the Long Term Evolution (LTE) technology. The tuning range is investigated and optimized with respect to the bandwidth and the efficiency of the resulting antenna. Simulatio...... and mock-ups are presented....

Intermediate levels of hippocampal activity appear optimal for associative memory formation.

Directory of Open Access Journals (Sweden)

Xiao Liu

Full Text Available BACKGROUND: It is well established that hippocampal activity is positively related to effective associative memory formation. However, in biological systems often optimal levels of activity are contrasted by both sub- and supra-optimal levels. Sub-optimal levels of hippocampal activity are commonly attributed to unsuccessful memory formation, whereas the supra-optimal levels of hippocampal activity related to unsuccessful memory formation have been rarely studied. It is still unclear under what circumstances such supra-optimal levels of hippocampal activity occur. To clarify this issue, we aimed at creating a condition, in which supra-optimal hippocampal activity is associated with encoding failure. We assumed that such supra-optimal activity occurs when task-relevant information is embedded in task-irrelevant, distracting information, which can be considered as noise. METHODOLOGY/PRINCIPAL FINDINGS: In the present fMRI study, we probed neural correlates of associative memory formation in a full-factorial design with associative memory (subsequently remembered versus forgotten and noise (induced by high versus low distraction as factors. Results showed that encoding failure was associated with supra-optimal activity in the high-distraction condition and with sub-optimal activity in the low distraction condition. Thus, we revealed evidence for a bell-shape function relating hippocampal activity with associative encoding success. CONCLUSIONS/SIGNIFICANCE: Our findings indicate that intermediate levels of hippocampal activity are optimal while both too low and too high levels appear detrimental for associative memory formation. Supra-optimal levels of hippocampal activity seem to occur when task-irrelevant information is added to task-relevant signal. If such task-irrelevant noise is reduced adequately, hippocampal activity is lower and thus optimal for associative memory formation.

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...

emMAW: computing minimal absent words in external memory.

Science.gov (United States)

Héliou, Alice; Pissis, Solon P; Puglisi, Simon J

2017-09-01

The biological significance of minimal absent words has been investigated in genomes of organisms from all domains of life. For instance, three minimal absent words of the human genome were found in Ebola virus genomes. There exists an O(n) -time and O(n) -space algorithm for computing all minimal absent words of a sequence of length n on a fixed-sized alphabet based on suffix arrays. A standard implementation of this algorithm, when applied to a large sequence of length n , requires more than 20 n  bytes of RAM. Such memory requirements are a significant hurdle to the computation of minimal absent words in large datasets. We present emMAW, the first external-memory algorithm for computing minimal absent words. A free open-source implementation of our algorithm is made available. This allows for computation of minimal absent words on far bigger data sets than was previously possible. Our implementation requires less than 3 h on a standard workstation to process the full human genome when as little as 1 GB of RAM is made available. We stress that our implementation, despite making use of external memory, is fast; indeed, even on relatively smaller datasets when enough RAM is available to hold all necessary data structures, it is less than two times slower than state-of-the-art internal-memory implementations. https://github.com/solonas13/maw (free software under the terms of the GNU GPL). alice.heliou@lix.polytechnique.fr or solon.pissis@kcl.ac.uk. Supplementary data are available at Bioinformatics online. © The Author (2017). Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com

Design of planar microcoil-based NMR probe ensuring high SNR

Science.gov (United States)

Ali, Zishan; Poenar, D. P.; Aditya, Sheel

2017-09-01

A microNMR probe for ex vivo applications may consist of at least one microcoil, which can be used as the oscillating magnetic field (MF) generator as well as receiver coil, and a sample holder, with a volume in the range of nanoliters to micro-liters, placed near the microcoil. The Signal-to-Noise ratio (SNR) of such a probe is, however, dependent not only on its design but also on the measurement setup, and the measured sample. This paper introduces a performance factor P independent of both the proton spin density in the sample and the external DC magnetic field, and which can thus assess the performance of the probe alone. First, two of the components of the P factor (inhomogeneity factor K and filling factor η ) are defined and an approach to calculate their values for different probe variants from electromagnetic simulations is devised. A criterion based on dominant component of the magnetic field is then formulated to help designers optimize the sample volume which also affects the performance of the probe, in order to obtain the best SNR for a given planar microcoil. Finally, the P factor values are compared between different planar microcoils with different number of turns and conductor aspect ratios, and planar microcoils are also compared with conventional solenoids. These comparisons highlight which microcoil geometry-sample volume combination will ensure a high SNR under any external setup.

Design of planar microcoil-based NMR probe ensuring high SNR

Directory of Open Access Journals (Sweden)

Zishan Ali

2017-09-01

Full Text Available A microNMR probe for ex vivo applications may consist of at least one microcoil, which can be used as the oscillating magnetic field (MF generator as well as receiver coil, and a sample holder, with a volume in the range of nanoliters to micro-liters, placed near the microcoil. The Signal-to-Noise ratio (SNR of such a probe is, however, dependent not only on its design but also on the measurement setup, and the measured sample. This paper introduces a performance factor P independent of both the proton spin density in the sample and the external DC magnetic field, and which can thus assess the performance of the probe alone. First, two of the components of the P factor (inhomogeneity factor K and filling factor η are defined and an approach to calculate their values for different probe variants from electromagnetic simulations is devised. A criterion based on dominant component of the magnetic field is then formulated to help designers optimize the sample volume which also affects the performance of the probe, in order to obtain the best SNR for a given planar microcoil. Finally, the P factor values are compared between different planar microcoils with different number of turns and conductor aspect ratios, and planar microcoils are also compared with conventional solenoids. These comparisons highlight which microcoil geometry-sample volume combination will ensure a high SNR under any external setup.

Worst-case efficient external-memory priority queues

DEFF Research Database (Denmark)

Brodal, Gerth Stølting; Katajainen, Jyrki

1998-01-01

A priority queue Q is a data structure that maintains a collection of elements, each element having an associated priority drawn from a totally ordered universe, under the operations Insert, which inserts an element into Q, and DeleteMin, which deletes an element with the minimum priority from Q....... In this paper a priority-queue implementation is given which is efficient with respect to the number of block transfers or I/Os performed between the internal and external memories of a computer. Let B and M denote the respective capacity of a block and the internal memory measured in elements. The developed...... data structure handles any intermixed sequence of Insert and DeleteMin operations such that in every disjoint interval of B consecutive priorityqueue operations at most clogM/B N/M I/Os are performed, for some positive constant c. These I/Os are divided evenly among the operations: if B ≥ clogM/B N...

An External Archive-Guided Multiobjective Particle Swarm Optimization Algorithm.

Science.gov (United States)

Zhu, Qingling; Lin, Qiuzhen; Chen, Weineng; Wong, Ka-Chun; Coello Coello, Carlos A; Li, Jianqiang; Chen, Jianyong; Zhang, Jun

2017-09-01

The selection of swarm leaders (i.e., the personal best and global best), is important in the design of a multiobjective particle swarm optimization (MOPSO) algorithm. Such leaders are expected to effectively guide the swarm to approach the true Pareto optimal front. In this paper, we present a novel external archive-guided MOPSO algorithm (AgMOPSO), where the leaders for velocity update are all selected from the external archive. In our algorithm, multiobjective optimization problems (MOPs) are transformed into a set of subproblems using a decomposition approach, and then each particle is assigned accordingly to optimize each subproblem. A novel archive-guided velocity update method is designed to guide the swarm for exploration, and the external archive is also evolved using an immune-based evolutionary strategy. These proposed approaches speed up the convergence of AgMOPSO. The experimental results fully demonstrate the superiority of our proposed AgMOPSO in solving most of the test problems adopted, in terms of two commonly used performance measures. Moreover, the effectiveness of our proposed archive-guided velocity update method and immune-based evolutionary strategy is also experimentally validated on more than 30 test MOPs.

An optimal multi-channel memory controller for real-time systems

NARCIS (Netherlands)

Gomony, M.D.; Akesson, K.B.; Goossens, K.G.W.

2013-01-01

Optimal utilization of a multi-channel memory, such as Wide IO DRAM, as shared memory in multi-processor platforms depends on the mapping of memory clients to the memory channels, the granularity at which the memory requests are interleaved in each channel, and the bandwidth and memory capacity

Hänsel, Gretel and the slime mould—how an external spatial memory aids navigation in complex environments

International Nuclear Information System (INIS)

Smith-Ferguson, Jules; Latty, Tanya; Beekman, Madeleine; Reid, Chris R

2017-01-01

The ability to navigate through an environment is critical to most organisms’ ability to survive and reproduce. The presence of a memory system greatly enhances navigational success. Therefore, natural selection is likely to drive the creation of memory systems, even in non-neuronal organisms, if having such a system is adaptive. Here we examine if the external spatial memory system present in the acellular slime mould, Physarum polycephalum , provides an adaptive advantage for resource acquisition. P. polycephalum lays tracks of extracellular slime as it moves through its environment. Previous work has shown that the presence of extracellular slime allows the organism to escape from a trap in laboratory experiments simply by avoiding areas previously explored. Here we further investigate the benefits of using extracellular slime as an external spatial memory by testing the organism’s ability to navigate through environments of differing complexity with and without the ability to use its external memory. Our results suggest that the external memory has an adaptive advantage in ‘open’ and simple bounded environments. However, in a complex bounded environment, the extracellular slime provides no advantage, and may even negatively affect the organism’s navigational abilities. Our results indicate that the exact experimental set up matters if one wants to fully understand how the presence of extracellular slime affects the slime mould’s search behaviour. (paper)

Hänsel, Gretel and the slime mould—how an external spatial memory aids navigation in complex environments

Science.gov (United States)

Smith-Ferguson, Jules; Reid, Chris R.; Latty, Tanya; Beekman, Madeleine

2017-10-01

The ability to navigate through an environment is critical to most organisms’ ability to survive and reproduce. The presence of a memory system greatly enhances navigational success. Therefore, natural selection is likely to drive the creation of memory systems, even in non-neuronal organisms, if having such a system is adaptive. Here we examine if the external spatial memory system present in the acellular slime mould, Physarum polycephalum, provides an adaptive advantage for resource acquisition. P. polycephalum lays tracks of extracellular slime as it moves through its environment. Previous work has shown that the presence of extracellular slime allows the organism to escape from a trap in laboratory experiments simply by avoiding areas previously explored. Here we further investigate the benefits of using extracellular slime as an external spatial memory by testing the organism’s ability to navigate through environments of differing complexity with and without the ability to use its external memory. Our results suggest that the external memory has an adaptive advantage in ‘open’ and simple bounded environments. However, in a complex bounded environment, the extracellular slime provides no advantage, and may even negatively affect the organism’s navigational abilities. Our results indicate that the exact experimental set up matters if one wants to fully understand how the presence of extracellular slime affects the slime mould’s search behaviour.

Modeling the planar configuration of extraordinary magnetoresistance

International Nuclear Information System (INIS)

El-Ahmar, S; Pozniak, A A

2015-01-01

Recently the planar version of the extraordinary magnetoresistance (EMR) magnetic field sensor has been constructed and verified in practice. Planar configuration of the EMR device gives many technological advantages, it is simpler than the classic and allows one to build the sensor using electric materials of the new type (such as graphene or topological insulators) much easier. In this work the planar configuration of the EMR sensor is investigated by performing computational simulations using the finite element method (FEM). The computational comparison of the planar and classic configurations of EMR is presented using three-dimensional models. Various variants of the geometry of EMR sensor components are pondered and compared in the planar and classic version. Size of the metal overlap is considered for sensor optimization as well as various semiconductor-metal contact resistance dependences of the EMR signal. Based on computational simulations, a method for optimal placement of electric terminals in a planar EMR device is proposed. (paper)

Planar Submillimeter-Wave Mixer Technology with Integrated Antenna

Science.gov (United States)

Chattopadhyay, Gautam; Mehdi, Imran; Gill, John J.; Lee, Choonsup; lombart, Muria L.; Thomas, Betrand

2010-01-01

High-performance mixers at terahertz frequencies require good matching between the coupling circuits such as antennas and local oscillators and the diode embedding impedance. With the availability of amplifiers at submillimeter wavelengths and the need to have multi-pixel imagers and cameras, planar mixer architecture is required to have an integrated system. An integrated mixer with planar antenna provides a compact and optimized design at terahertz frequencies. Moreover, it leads to a planar architecture that enables efficient interconnect with submillimeter-wave amplifiers. In this architecture, a planar slot antenna is designed on a thin gallium arsenide (GaAs) membrane in such a way that the beam on either side of the membrane is symmetric and has good beam profile with high coupling efficiency. A coplanar waveguide (CPW) coupled Schottky diode mixer is designed and integrated with the antenna. In this architecture, the local oscillator (LO) is coupled through one side of the antenna and the RF from the other side, without requiring any beam sp litters or diplexers. The intermediate frequency (IF) comes out on a 50-ohm CPW line at the edge of the mixer chip, which can be wire-bonded to external circuits. This unique terahertz mixer has an integrated single planar antenna for coupling both the radio frequency (RF) input and LO injection without any diplexer or beamsplitters. The design utilizes novel planar slot antenna architecture on a 3- mthick GaAs membrane. This work is required to enable future multi-pixel terahertz receivers for astrophysics missions, and lightweight and compact receivers for planetary missions to the outer planets in our solar system. Also, this technology can be used in tera hertz radar imaging applications as well as for testing of quantum cascade lasers (QCLs).

Contracting a planar graph efficiently

DEFF Research Database (Denmark)

Holm, Jacob; Italiano, Giuseppe F.; Karczmarz, Adam

2017-01-01

the data structure, we can achieve optimal running times for decremental bridge detection, 2-edge connectivity, maximal 3-edge connected components, and the problem of finding a unique perfect matching for a static planar graph. Furthermore, we improve the running times of algorithms for several planar...

An extended continuum model considering optimal velocity change with memory and numerical tests

Science.gov (United States)

Qingtao, Zhai; Hongxia, Ge; Rongjun, Cheng

2018-01-01

In this paper, an extended continuum model of traffic flow is proposed with the consideration of optimal velocity changes with memory. The new model's stability condition and KdV-Burgers equation considering the optimal velocities change with memory are deduced through linear stability theory and nonlinear analysis, respectively. Numerical simulation is carried out to study the extended continuum model, which explores how optimal velocity changes with memory affected velocity, density and energy consumption. Numerical results show that when considering the effects of optimal velocity changes with memory, the traffic jams can be suppressed efficiently. Both the memory step and sensitivity parameters of optimal velocity changes with memory will enhance the stability of traffic flow efficiently. Furthermore, numerical results demonstrates that the effect of optimal velocity changes with memory can avoid the disadvantage of historical information, which increases the stability of traffic flow on road, and so it improve the traffic flow stability and minimize cars' energy consumptions.

General planar transverse domain walls realized by optimized transverse magnetic field pulses in magnetic biaxial nanowires

Science.gov (United States)

Li, Mei; Wang, Jianbo; Lu, Jie

2017-02-01

The statics and field-driven dynamics of transverse domain walls (TDWs) in magnetic nanowires (NWs) have attracted continuous interests because of their theoretical significance and application potential in future magnetic logic and memory devices. Recent results demonstrate that uniform transverse magnetic fields (TMFs) can greatly enhance the wall velocity, meantime leave a twisting in the TDW azimuthal distribution. For application in high-density NW devices, it is preferable to erase the twisting so as to minimize magnetization frustrations. Here we report the realization of a completely planar TDW with arbitrary tilting attitude in a magnetic biaxial NW under a TMF pulse with fixed strength and well-designed orientation profile. We smooth any twisting in the TDW azimuthal plane thus completely decouple the polar and azimuthal degrees of freedom. The analytical differential equation describing the polar angle distribution is derived and the resulting solution is not the Walker-ansatz form. With this TMF pulse comoving, the field-driven dynamics of the planar TDW is investigated with the help of the asymptotic expansion method. It turns out the comoving TMF pulse increases the wall velocity under the same axial driving field. These results will help to design a series of modern magnetic devices based on planar TDWs.

Optimization of externalities using DTM measures: a Pareto optimal multi objective optimization using the evolutionary algorithm SPEA2+

NARCIS (Netherlands)

Wismans, Luc Johannes Josephus; van Berkum, Eric C.; Bliemer, Michiel; Allkim, T.P.; van Arem, Bart

2010-01-01

Multi objective optimization of externalities of traffic is performed solving a network design problem in which Dynamic Traffic Management measures are used. The resulting Pareto optimal set is determined by employing the SPEA2+ evolutionary algorithm.

Analogical Reasoning in Adolescents with Intellectual Disability: Effects of External Memories and Time Processing

Science.gov (United States)

Denaes, Caroline; Berger, Jean-Louis

2014-01-01

Analogical reasoning involves the comparison of pictures as well as the memorisation of relations. Young children (4-7 years old) and students with moderate intellectual disability have a short memory span, which hampers them in succeeding traditional analogical tests. In the present study, we investigated if, by providing external memory hints,…

Two routes toward optimism: how agentic and communal themes in autobiographical memories guide optimism for the future.

Science.gov (United States)

Austin, Adrienne; Costabile, Kristi

2017-11-01

Autobiographical memories are particularly adaptive because they function not only to preserve the past, but also to direct our future thoughts and behaviours. Two studies were conducted to examine how communal and agentic themes of positive autobiographical memories differentially predicted the route from autobiographical memories to optimism for the future. Across two studies, results revealed that the degree to which participants focused on communal themes in their autobiographical memories predicted their experience of nostalgia. In turn, the experience of nostalgia increased participants' levels of self-esteem and in turn, optimism for the future. By contrast, the degree to which participants focused on agentic themes in their memories predicted self-esteem and optimism, operating outside the experience of nostalgia. These effects remained even after controlling for self-focused attention. Together, these studies provide greater understanding of the interrelations among autobiographical memory, self-concept, and time, and demonstrate how agency and communion operate to influence perceptions of one's future when thinking about the past.

Recovering Faces from Memory: The Distracting Influence of External Facial Features

Science.gov (United States)

Frowd, Charlie D.; Skelton, Faye; Atherton, Chris; Pitchford, Melanie; Hepton, Gemma; Holden, Laura; McIntyre, Alex H.; Hancock, Peter J. B.

2012-01-01

Recognition memory for unfamiliar faces is facilitated when contextual cues (e.g., head pose, background environment, hair and clothing) are consistent between study and test. By contrast, inconsistencies in external features, especially hair, promote errors in unfamiliar face-matching tasks. For the construction of facial composites, as carried…

The working memory stroop effect: when internal representations clash with external stimuli.

Science.gov (United States)

Kiyonaga, Anastasia; Egner, Tobias

2014-08-01

Working memory (WM) has recently been described as internally directed attention, which implies that WM content should affect behavior exactly like an externally perceived and attended stimulus. We tested whether holding a color word in WM, rather than attending to it in the external environment, can produce interference in a color-discrimination task, which would mimic the classic Stroop effect. Over three experiments, the WM Stroop effect recapitulated core properties of the classic attentional Stroop effect, displaying equivalent congruency effects, additive contributions from stimulus- and response-level congruency, and susceptibility to modulation by the percentage of congruent and incongruent trials. Moreover, WM maintenance was inversely related to attentional demands during the WM delay between stimulus presentation and recall, with poorer memory performance following incongruent than congruent trials. Together, these results suggest that WM and attention rely on the same resources and operate over the same representations. © The Author(s) 2014.

Piezo Voltage Controlled Planar Hall Effect Devices.

Science.gov (United States)

Zhang, Bao; Meng, Kang-Kang; Yang, Mei-Yin; Edmonds, K W; Zhang, Hao; Cai, Kai-Ming; Sheng, Yu; Zhang, Nan; Ji, Yang; Zhao, Jian-Hua; Zheng, Hou-Zhi; Wang, Kai-You

2016-06-22

The electrical control of the magnetization switching in ferromagnets is highly desired for future spintronic applications. Here we report on hybrid piezoelectric (PZT)/ferromagnetic (Co2FeAl) devices in which the planar Hall voltage in the ferromagnetic layer is tuned solely by piezo voltages. The change of planar Hall voltage is associated with magnetization switching through 90° in the plane under piezo voltages. Room temperature magnetic NOT and NOR gates are demonstrated based on the piezo voltage controlled Co2FeAl planar Hall effect devices without the external magnetic field. Our demonstration may lead to the realization of both information storage and processing using ferromagnetic materials.

Neuroimaging markers associated with maintenance of optimal memory performance in late-life.

Science.gov (United States)

Dekhtyar, Maria; Papp, Kathryn V; Buckley, Rachel; Jacobs, Heidi I L; Schultz, Aaron P; Johnson, Keith A; Sperling, Reisa A; Rentz, Dorene M

2017-06-01

Age-related memory decline has been well-documented; however, some individuals reach their 8th-10th decade while maintaining strong memory performance. To determine which demographic and biomarker factors differentiated top memory performers (aged 75+, top 20% for memory) from their peers and whether top memory performance was maintained over 3 years. Clinically normal adults (n=125, CDR=0; age: 79.5±3.57 years) from the Harvard Aging Brain Study underwent cognitive testing and neuroimaging (amyloid PET, MRI) at baseline and 3-year follow-up. Participants were grouped into Optimal (n=25) vs. Typical (n=100) performers using performance on 3 challenging memory measures. Non-parametric tests were used to compare groups. There were no differences in age, sex, or education between Optimal vs. Typical performers. The Optimal group performed better in Processing Speed (p=0.016) and Executive Functioning (pmemory performance while 7 declined. Non-Maintainers additionally declined in Executive Functioning but not Processing Speed. Longitudinally, there were no hippocampal volume differences between Maintainers and Non-Maintainers, however Non-Maintainers exhibited higher amyloid burden at baseline in contrast with Maintainers (p=0.008). Excellent memory performance in late life does not guarantee protection against cognitive decline. Those who maintain an optimal memory into the 8th and 9th decades may have lower levels of AD pathology. Copyright © 2017. Published by Elsevier Ltd.

Size, shape, and topology optimization of planar and space trusses using mutation-based improved metaheuristics

Directory of Open Access Journals (Sweden)

Ghanshyam G. Tejani

2018-04-01

Full Text Available In this study, simultaneous size, shape, and topology optimization of planar and space trusses are investigated. Moreover, the trusses are subjected to constraints for element stresses, nodal displacements, and kinematic stability conditions. Truss Topology Optimization (TTO removes the superfluous elements and nodes from the ground structure. In this method, the difficulties arise due to unacceptable and singular topologies; therefore, the Grubler’s criterion and the positive definiteness are used to handle such issue. Moreover, the TTO is challenging due to its search space, which is implicit, non-convex, non-linear, and often leading to divergence. Therefore, mutation-based metaheuristics are proposed to investigate them. This study compares the performance of four improved metaheuristics (viz. Improved Teaching–Learning-Based Optimization (ITLBO, Improved Heat Transfer Search (IHTS, Improved Water Wave Optimization (IWWO, and Improved Passing Vehicle Search (IPVS and four basic metaheuristics (viz. TLBO, HTS, WWO, and PVS in order to solve structural optimization problems. Keywords: Structural optimization, Mutation operator, Improved metaheuristics, Modified algorithms, Truss topology optimization

Yangian-type symmetries of non-planar leading singularities

Energy Technology Data Exchange (ETDEWEB)

Frassek, Rouven [Department of Mathematical Sciences, Durham University,South Road, Durham DH1 3LE (United Kingdom); Meidinger, David [Institut für Mathematik und Institut für Physik, Humboldt-Universität zu Berlin,Zum Großen Windkanal 6, 12489 Berlin (Germany)

2016-05-18

We take up the study of integrable structures behind non-planar contributions to scattering amplitudes in N = 4 super Yang-Mills theory. Focusing on leading singularities, we derive the action of the Yangian generators on color-ordered subsets of the external states. Each subset corresponds to a single boundary of the non-planar on-shell diagram. While Yangian invariance is broken, we find that higher-level Yangian generators still annihilate the non-planar on-shell diagram. For a given diagram, the number of these generators is governed by the degree of non-planarity. Furthermore, we present additional identities involving integrable transfer matrices. In particular, for diagrams on a cylinder we obtain a conservation rule similar to the Yangian invariance condition of planar on-shell diagrams. To exemplify our results, we consider a five-point MHV on-shell function on a cylinder.

The impact of cognitive control, incentives, and working memory load on the P3 responses of externalizing prisoners.

Science.gov (United States)

Baskin-Sommers, Arielle R; Krusemark, Elizabeth A; Curtin, John J; Lee, Christopher; Vujnovich, Aleice; Newman, Joseph P

2014-02-01

The P3 amplitude reduction is one of the most common correlates of externalizing. However, few studies have used experimental manipulations designed to challenge different cognitive functions in order to clarify the processes that impact this reduction. To examine factors moderating P3 amplitude in trait externalizing, we administered an n-back task that manipulated cognitive control demands, working memory load, and incentives to a sample of male offenders. Offenders with high trait externalizing scores did not display a global reduction in P3 amplitude. Rather, the negative association between trait externalizing and P3 amplitude was specific to trials involving inhibition of a dominant response during infrequent stimuli, in the context of low working memory load, and incentives for performance. In addition, we discuss the potential implications of these findings for externalizing-related psychopathologies. The results complement and expand previous work on the process-level dysfunction contributing to externalizing-related deficits in P3. Copyright © 2013 Elsevier B.V. All rights reserved.

Optimizing main-memory join on modern hardware

OpenAIRE

Boncz, Peter; Manegold, Stefan; Kersten, Martin

2002-01-01

textabstractIn the past decade, the exponential growth in commodity CPUs speed has far outpaced advances in memory latency. A second trend is that CPU performance advances are not only brought by increased clock rate, but also by increasing parallelism inside the CPU. Current database systems have not yet adapted to these trends, and show poor utilization of both CPU and memory resources on current hardware. In this article, we show how these resources can be optimized for large joins and tra...

Optimal colour quality of LED clusters based on memory colours.

Science.gov (United States)

Smet, Kevin; Ryckaert, Wouter R; Pointer, Michael R; Deconinck, Geert; Hanselaer, Peter

2011-03-28

The spectral power distributions of tri- and tetrachromatic clusters of Light-Emitting-Diodes, composed of simulated and commercially available LEDs, were optimized with a genetic algorithm to maximize the luminous efficacy of radiation and the colour quality as assessed by the memory colour quality metric developed by the authors. The trade-off of the colour quality as assessed by the memory colour metric and the luminous efficacy of radiation was investigated by calculating the Pareto optimal front using the NSGA-II genetic algorithm. Optimal peak wavelengths and spectral widths of the LEDs were derived, and over half of them were found to be close to Thornton's prime colours. The Pareto optimal fronts of real LED clusters were always found to be smaller than those of the simulated clusters. The effect of binning on designing a real LED cluster was investigated and was found to be quite large. Finally, a real LED cluster of commercially available AlGaInP, InGaN and phosphor white LEDs was optimized to obtain a higher score on memory colour quality scale than its corresponding CIE reference illuminant.

State diagram of spin-torque oscillator with perpendicular reference layer and planar field generation layer

Directory of Open Access Journals (Sweden)

Mengwei Zhang

2015-06-01

Full Text Available The state diagram of spin-torque oscillator (STO with perpendicular reference layer (REF and planar field generation layer (FGL was studied by a macrospin model and a micro-magnetic model. The state diagrams are calculated versus the current density, external field and external field angle. It was found that the oscillation in FGL could be controlled by current density combined with external field so as to achieve a wide frequency range. An optimized current and applied field region was given for microwave assisted magnetic recording (MAMR, considering both frequency and output field oscillation amplitude. The results of the macro-spin model were compared with those of the micro-magnetic model. The macro-spin model was qualitatively different from micro-magnetics and experimental results when the current density was large and the FGL was non-uniform.

Optimal proximity correction: application for flash memory design

Science.gov (United States)

Chen, Y. O.; Huang, D. L.; Sung, K. T.; Chiang, J. J.; Yu, M.; Teng, F.; Chu, Lung; Rey, Juan C.; Bernard, Douglas A.; Li, Jiangwei; Li, Junling; Moroz, V.; Boksha, Victor V.

1998-06-01

Proximity Correction is the technology for which the most of IC manufacturers are committed already. The final intended result of correction is affected by many factors other than the optical characteristics of the mask-stepper system, such as photoresist exposure, post-exposure bake and development parameters, etch selectivity and anisotropy, and underlying topography. The most advanced industry and research groups already reported immediate need to consider wafer topography as one of the major components during a Proximity Correction procedure. In the present work we are discussing the corners rounding effect (which eventually cause electrical leakage) observed for the elements of Poly2 layer for a Flash Memory Design. It was found that the rounding originated by three- dimensional effects due to variation of photoresist thickness resulting from the non-planar substrate. Our major goal was to understand the reasons and correct corner rounding. As a result of this work highly effective layout correction methodology was demonstrated and manufacturable Depth Of Focus was achieved. Another purpose of the work was to demonstrate complete integration flow for a Flash Memory Design based on photolithography; deposition/etch; ion implantation/oxidation/diffusion; and device simulators.

A New Local Bipolar Autoassociative Memory Based on External Inputs of Discrete Recurrent Neural Networks With Time Delay.

Science.gov (United States)

Zhou, Caigen; Zeng, Xiaoqin; Luo, Chaomin; Zhang, Huaguang

In this paper, local bipolar auto-associative memories are presented based on discrete recurrent neural networks with a class of gain type activation function. The weight parameters of neural networks are acquired by a set of inequalities without the learning procedure. The global exponential stability criteria are established to ensure the accuracy of the restored patterns by considering time delays and external inputs. The proposed methodology is capable of effectively overcoming spurious memory patterns and achieving memory capacity. The effectiveness, robustness, and fault-tolerant capability are validated by simulated experiments.In this paper, local bipolar auto-associative memories are presented based on discrete recurrent neural networks with a class of gain type activation function. The weight parameters of neural networks are acquired by a set of inequalities without the learning procedure. The global exponential stability criteria are established to ensure the accuracy of the restored patterns by considering time delays and external inputs. The proposed methodology is capable of effectively overcoming spurious memory patterns and achieving memory capacity. The effectiveness, robustness, and fault-tolerant capability are validated by simulated experiments.

Optimal condition of memristance enhancement circuit using external voltage source

Directory of Open Access Journals (Sweden)

Hiroya Tanaka

2014-05-01

Full Text Available Memristor provides nonlinear response in the current-voltage characteristic and the memristance is modulated using an external voltage source. We point out by solving nonlinear equations that an optimal condition of the external voltage source exists for maximizing the memristance in such modulation scheme. We introduce a linear function to describe the nonlinear time response and derive an important design guideline; a constant ratio of the frequency to the amplitude of the external voltage source maximizes the memristance. The analysis completely accounts for the memristance behavior.

Nb multilayer planarization technology for a subnanosecond Josephson 1K-bit RAM

International Nuclear Information System (INIS)

Nagasawa, S.; Wada, Y.; Tsuge, H.; Hidaka, M.; Ishida, I.; Tahara, S.

1989-01-01

Nb multilayer planarization technology has been developed. This planarization technology consists of an etch-back technique using 2000-molecular weight polystyrene and SiO/sub 2/ for the junction layer and wiring layers, and a tapered edge etching technique for contact between individual wiring layers. A Josephson 1K-bit random access memory (RAM) has been fabricated using this planarization technology. Excellent planarity, wherein level differences in all step areas are reduced to less than 1/20th of their original value, was achieved in the multilayer structure of the RAM. Moreover, appropriate RAM operations, with 570ps minimum access time and 13mW power dissipation, were confirmed

Maternal depression and trajectories of child internalizing and externalizing problems: the roles of child decision making and working memory.

Science.gov (United States)

Flouri, E; Ruddy, A; Midouhas, E

2017-04-01

Maternal depression may affect the emotional/behavioural outcomes of children with normal neurocognitive functioning less severely than it does those without. To guide prevention and intervention efforts, research must specify which aspects of a child's cognitive functioning both moderate the effect of maternal depression and are amenable to change. Working memory and decision making may be amenable to change and are so far unexplored as moderators of this effect. Our sample was 17 160 Millennium Cohort Study children. We analysed trajectories of externalizing (conduct and hyperactivity) and internalizing (emotional and peer) problems, measured with the Strengths and Difficulties Questionnaire at the ages 3, 5, 7 and 11 years, using growth curve models. We characterized maternal depression, also time-varying at these ages, by a high score on the K6. Working memory was measured with the Cambridge Neuropsychological Test Automated Battery Spatial Working Memory Task, and decision making (risk taking and quality of decision making) with the Cambridge Gambling Task, both at age 11 years. Maternal depression predicted both the level and the growth of problems. Risk taking and poor-quality decision making were related positively to externalizing and non-significantly to internalizing problems. Poor working memory was related to both problem types. Neither decision making nor working memory explained the effect of maternal depression on child internalizing/externalizing problems. Importantly, risk taking amplified the effect of maternal depression on internalizing problems, and poor working memory that on internalizing and conduct problems. Impaired decision making and working memory in children amplify the adverse effect of maternal depression on, particularly, internalizing problems.

Numerical simulation and optimal design of Segmented Planar Imaging Detector for Electro-Optical Reconnaissance

Science.gov (United States)

Chu, Qiuhui; Shen, Yijie; Yuan, Meng; Gong, Mali

2017-12-01

Segmented Planar Imaging Detector for Electro-Optical Reconnaissance (SPIDER) is a cutting-edge electro-optical imaging technology to realize miniaturization and complanation of imaging systems. In this paper, the principle of SPIDER has been numerically demonstrated based on the partially coherent light theory, and a novel concept of adjustable baseline pairing SPIDER system has further been proposed. Based on the results of simulation, it is verified that the imaging quality could be effectively improved by adjusting the Nyquist sampling density, optimizing the baseline pairing method and increasing the spectral channel of demultiplexer. Therefore, an adjustable baseline pairing algorithm is established for further enhancing the image quality, and the optimal design procedure in SPIDER for arbitrary targets is also summarized. The SPIDER system with adjustable baseline pairing method can broaden its application and reduce cost under the same imaging quality.

Evanescent field refractometry in planar optical fiber.

Science.gov (United States)

Holmes, Christopher; Jantzen, Alexander; Gray, Alan C; Gow, Paul C; Carpenter, Lewis G; Bannerman, Rex H S; Gates, James C; Smith, Peter G R

2018-02-15

This Letter demonstrates a refractometer in integrated optical fiber, a new optical platform that planarizes fiber using flame hydrolysis deposition (FHD). The unique advantage of the technology is survivability in harsh environments. The platform is mechanically robust, and can survive elevated temperatures approaching 1000°C and exposure to common solvents, including acetone, gasoline, and methanol. For the demonstrated refractometer, fabrication was achieved through wet etching an SMF-28 fiber to a diameter of 8 μm before FHD planarization. An external refractive index was monitored using fiber Bragg gratings (FBGs), written into the core of the planarized fiber. A direct comparison to alternative FBG refractometers is made, for which the developed platform is shown to have comparable sensitivity, with the added advantage of survivability in harsh environments.

External details revisited - A new taxonomy for coding 'non-episodic' content during autobiographical memory retrieval.

Science.gov (United States)

Strikwerda-Brown, Cherie; Mothakunnel, Annu; Hodges, John R; Piguet, Olivier; Irish, Muireann

2018-04-24

Autobiographical memory (ABM) is typically held to comprise episodic and semantic elements, with the vast majority of studies to date focusing on profiles of episodic details in health and disease. In this context, 'non-episodic' elements are often considered to reflect semantic processing or are discounted from analyses entirely. Mounting evidence suggests that rather than reflecting one unitary entity, semantic autobiographical information may contain discrete subcomponents, which vary in their relative degree of semantic or episodic content. This study aimed to (1) review the existing literature to formally characterize the variability in analysis of 'non-episodic' content (i.e., external details) on the Autobiographical Interview and (2) use these findings to create a theoretically grounded framework for coding external details. Our review exposed discrepancies in the reporting and interpretation of external details across studies, reinforcing the need for a new, consistent approach. We validated our new external details scoring protocol (the 'NExt' taxonomy) in patients with Alzheimer's disease (n = 18) and semantic dementia (n = 13), and 20 healthy older Control participants and compared profiles of the NExt subcategories across groups and time periods. Our results revealed increased sensitivity of the NExt taxonomy in discriminating between ABM profiles of patient groups, when compared to traditionally used internal and external detail metrics. Further, remote and recent autobiographical memories displayed distinct compositions of the NExt detail types. This study is the first to provide a fine-grained and comprehensive taxonomy to parse external details into intuitive subcategories and to validate this protocol in neurodegenerative disorders. © 2018 The British Psychological Society.

Intermediate levels of hippocampal activity appear optimal for associative memory formation.

NARCIS (Netherlands)

Liu, X.; Qin, S.; Rijpkema, M.J.P.; Luo, J.; Fernandez, G.S.E.

2010-01-01

BACKGROUND: It is well established that hippocampal activity is positively related to effective associative memory formation. However, in biological systems often optimal levels of activity are contrasted by both sub- and supra-optimal levels. Sub-optimal levels of hippocampal activity are commonly

Comparison of memory thresholds for planar qudit geometries

Science.gov (United States)

Marks, Jacob; Jochym-O'Connor, Tomas; Gheorghiu, Vlad

2017-11-01

We introduce and analyze a new type of decoding algorithm called general color clustering, based on renormalization group methods, to be used in qudit color codes. The performance of this decoder is analyzed under a generalized bit-flip error model, and is used to obtain the first memory threshold estimates for qudit 6-6-6 color codes. The proposed decoder is compared with similar decoding schemes for qudit surface codes as well as the current leading qubit decoders for both sets of codes. We find that, as with surface codes, clustering performs sub-optimally for qubit color codes, giving a threshold of 5.6 % compared to the 8.0 % obtained through surface projection decoding methods. However, the threshold rate increases by up to 112% for large qudit dimensions, plateauing around 11.9 % . All the analysis is performed using QTop, a new open-source software for simulating and visualizing topological quantum error correcting codes.

Scalable unit commitment by memory-bounded ant colony optimization with A{sup *} local search

Energy Technology Data Exchange (ETDEWEB)

Saber, Ahmed Yousuf; Alshareef, Abdulaziz Mohammed [Department of Electrical and Computer Engineering, King Abdulaziz University, P.O. Box 80204, Jeddah 21589 (Saudi Arabia)

2008-07-15

Ant colony optimization (ACO) is successfully applied in optimization problems. Performance of the basic ACO for small problems with moderate dimension and searching space is satisfactory. As the searching space grows exponentially in the large-scale unit commitment problem, the basic ACO is not applicable for the vast size of pheromone matrix of ACO in practical time and physical computer-memory limit. However, memory-bounded methods prune the least-promising nodes to fit the system in computer memory. Therefore, the authors propose memory-bounded ant colony optimization (MACO) in this paper for the scalable (no restriction for system size) unit commitment problem. This MACO intelligently solves the limitation of computer memory, and does not permit the system to grow beyond a bound on memory. In the memory-bounded ACO implementation, A{sup *} heuristic is introduced to increase local searching ability and probabilistic nearest neighbor method is applied to estimate pheromone intensity for the forgotten value. Finally, the benchmark data sets and existing methods are used to show the effectiveness of the proposed method. (author)

Optimization of field homogeneity of Helmholtz-like coils for measuring the balance of planar gradiometers

International Nuclear Information System (INIS)

Nordahn, M.A.; Holst, T.; Shen, Y.Q.

1999-01-01

Measuring the balance of planar SQUID gradiometers using a relatively small Helmholtz-like coil system requires a careful design of the coils in order to have a high degree of field uniformity along the radial direction. The level to which planar gradiometers can be balanced will be affected by any misalignment of the gradiometer relative to the ideal central position. Therefore, the maximum degree of balancing possible is calculated numerically for the Helmholtz geometry under various perturbations, including misalignment of the gradiometer along the cylindrical and the radial axis, and angular tilting relative to the normal plane. Furthermore, if the ratio between the coil separation and coil radius is chosen to be less than unity, calculations show that the expected radial uniformity of the field can be improved considerably compared to the traditional Helmholtz geometry. The optimized coil geometry is compared to the Helmholtz geometry and is found to yield up to an order of magnitude improvement of the worst case error signal within a volume spanned by the uncertainty in the alignment. (author)

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

DEFF Research Database (Denmark)

Arge, Lars; Meyer, Ulrich; Toma, Laura

2004-01-01

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

Memory and Energy Optimization Strategies for Multithreaded Operating System on the Resource-Constrained Wireless Sensor Node

Directory of Open Access Journals (Sweden)

Xing Liu

2014-12-01

Full Text Available Memory and energy optimization strategies are essential for the resource-constrained wireless sensor network (WSN nodes. In this article, a new memory-optimized and energy-optimized multithreaded WSN operating system (OS LiveOS is designed and implemented. Memory cost of LiveOS is optimized by using the stack-shifting hybrid scheduling approach. Different from the traditional multithreaded OS in which thread stacks are allocated statically by the pre-reservation, thread stacks in LiveOS are allocated dynamically by using the stack-shifting technique. As a result, memory waste problems caused by the static pre-reservation can be avoided. In addition to the stack-shifting dynamic allocation approach, the hybrid scheduling mechanism which can decrease both the thread scheduling overhead and the thread stack number is also implemented in LiveOS. With these mechanisms, the stack memory cost of LiveOS can be reduced more than 50% if compared to that of a traditional multithreaded OS. Not is memory cost optimized, but also the energy cost is optimized in LiveOS, and this is achieved by using the multi-core “context aware” and multi-core “power-off/wakeup” energy conservation approaches. By using these approaches, energy cost of LiveOS can be reduced more than 30% when compared to the single-core WSN system. Memory and energy optimization strategies in LiveOS not only prolong the lifetime of WSN nodes, but also make the multithreaded OS feasible to run on the memory-constrained WSN nodes.

A novel algorithm for kinematic and dynamic optimal synthesis of planar four-bar mechanisms with joint clearance

Energy Technology Data Exchange (ETDEWEB)

Daniali, H. M.; Dardel, M.; Fathi, A. [Babol University of Technology, Babol (Iran, Islamic Republic of); Varedi, S. M. [University of Shahrood, Shahrood (Iran, Islamic Republic of)

2015-05-15

In practice, clearances in the joints are inevitable due to tolerances and defects arising from design and manufacturing. Moreover, the joints undergo wear and backlash, resulting in poor accuracy and repeatability. This paper presents a novel optimization method for simultaneously kinematic and dynamic synthesis of a planar four-bar linkage with clearance at the joints. It is well-known that in the presence of clearance at a joint, the linkage gains an additional, uncontrollable degree of freedom which is the source of error. Here, we synthesis the path generation problem while controlling the unwanted degrees of freedom by revising the mass distributions of the moving links. An algorithm based on particle swarm optimization method solves this highly nonlinear optimization problem with some constraints. Finally, an example is included to demonstrate the efficiency of the algorithm. The results clearly show that the linear and angular accelerations of the links for the optimal design are very smooth and bounded.

Functional magnetic resonance imaging study of external source memory and its relation to cognitive insight in non-clinical subjects.

Science.gov (United States)

Buchy, Lisa; Hawco, Colin; Bodnar, Michael; Izadi, Sarah; Dell'Elce, Jennifer; Messina, Katrina; Lepage, Martin

2014-09-01

Previous research has linked cognitive insight (a measure of self-reflectiveness and self-certainty) in psychosis with neurocognitive and neuroanatomical disturbances in the fronto-hippocampal neural network. The authors' goal was to use functional magnetic resonance imaging (fMRI) to investigate the neural correlates of cognitive insight during an external source memory paradigm in non-clinical subjects. At encoding, 24 non-clinical subjects travelled through a virtual city where they came across 20 separate people, each paired with a unique object in a distinct location. fMRI data were then acquired while participants viewed images of the city, and completed source recognition memory judgments of where and with whom objects were seen, which is known to involve prefrontal cortex. Cognitive insight was assessed with the Beck Cognitive Insight Scale. External source memory was associated with neural activity in a widespread network consisting of frontal cortex, including ventrolateral prefrontal cortex (VLPFC), temporal and occipital cortices. Activation in VLPFC correlated with higher self-reflectiveness and activation in midbrain correlated with lower self-certainty during source memory attributions. Neither self-reflectiveness nor self-certainty significantly correlated with source memory accuracy. By means of virtual reality and in the context of an external source memory paradigm, the study identified a preliminary functional neural basis for cognitive insight in the VLPFC in healthy people that accords with our fronto-hippocampal theoretical model as well as recent neuroimaging data in people with psychosis. The results may facilitate the understanding of the role of neural mechanisms in psychotic disorders associated with cognitive insight distortions. © 2014 The Authors. Psychiatry and Clinical Neurosciences © 2014 Japanese Society of Psychiatry and Neurology.

Memory-Optimized Software Synthesis from Dataflow Program Graphs with Large Size Data Samples

Directory of Open Access Journals (Sweden)

Hyunok Oh

2003-05-01

Full Text Available In multimedia and graphics applications, data samples of nonprimitive type require significant amount of buffer memory. This paper addresses the problem of minimizing the buffer memory requirement for such applications in embedded software synthesis from graphical dataflow programs based on the synchronous dataflow (SDF model with the given execution order of nodes. We propose a memory minimization technique that separates global memory buffers from local pointer buffers: the global buffers store live data samples and the local buffers store the pointers to the global buffer entries. The proposed algorithm reduces 67% memory for a JPEG encoder, 40% for an H.263 encoder compared with unshared versions, and 22% compared with the previous sharing algorithm for the H.263 encoder. Through extensive buffer sharing optimization, we believe that automatic software synthesis from dataflow program graphs achieves the comparable code quality with the manually optimized code in terms of memory requirement.

External locus of control contributes to racial disparities in memory and reasoning training gains in ACTIVE

Science.gov (United States)

Zahodne, Laura B.; Meyer, Oanh L.; Choi, Eunhee; Thomas, Michael L.; Willis, Sherry L.; Marsiske, Michael; Gross, Alden L.; Rebok, George W.; Parisi, Jeanine M.

2015-01-01

Racial disparities in cognitive outcomes may be partly explained by differences in locus of control. African Americans report more external locus of control than non-Hispanic Whites, and external locus of control is associated with poorer health and cognition. The aims of this study were to compare cognitive training gains between African American and non-Hispanic White participants in the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study and determine whether racial differences in training gains are mediated by locus of control. The sample comprised 2,062 (26% African American) adults aged 65 and older who participated in memory, reasoning, or speed training. Latent growth curve models evaluated predictors of 10-year cognitive trajectories separately by training group. Multiple group modeling examined associations between training gains and locus of control across racial groups. Compared to non-Hispanic Whites, African Americans evidenced less improvement in memory and reasoning performance after training. These effects were partially mediated by locus of control, controlling for age, sex, education, health, depression, testing site, and initial cognitive ability. African Americans reported more external locus of control, which was associated with smaller training gains. External locus of control also had a stronger negative association with reasoning training gain for African Americans than for Whites. No racial difference in training gain was identified for speed training. Future intervention research with African Americans should test whether explicitly targeting external locus of control leads to greater cognitive improvement following cognitive training. PMID:26237116

Static Memory Deduplication for Performance Optimization in Cloud Computing

Directory of Open Access Journals (Sweden)

Gangyong Jia

2017-04-01

Full Text Available In a cloud computing environment, the number of virtual machines (VMs on a single physical server and the number of applications running on each VM are continuously growing. This has led to an enormous increase in the demand of memory capacity and subsequent increase in the energy consumption in the cloud. Lack of enough memory has become a major bottleneck for scalability and performance of virtualization interfaces in cloud computing. To address this problem, memory deduplication techniques which reduce memory demand through page sharing are being adopted. However, such techniques suffer from overheads in terms of number of online comparisons required for the memory deduplication. In this paper, we propose a static memory deduplication (SMD technique which can reduce memory capacity requirement and provide performance optimization in cloud computing. The main innovation of SMD is that the process of page detection is performed offline, thus potentially reducing the performance cost, especially in terms of response time. In SMD, page comparisons are restricted to the code segment, which has the highest shared content. Our experimental results show that SMD efficiently reduces memory capacity requirement and improves performance. We demonstrate that, compared to other approaches, the cost in terms of the response time is negligible.

Static Memory Deduplication for Performance Optimization in Cloud Computing.

Science.gov (United States)

Jia, Gangyong; Han, Guangjie; Wang, Hao; Yang, Xuan

2017-04-27

In a cloud computing environment, the number of virtual machines (VMs) on a single physical server and the number of applications running on each VM are continuously growing. This has led to an enormous increase in the demand of memory capacity and subsequent increase in the energy consumption in the cloud. Lack of enough memory has become a major bottleneck for scalability and performance of virtualization interfaces in cloud computing. To address this problem, memory deduplication techniques which reduce memory demand through page sharing are being adopted. However, such techniques suffer from overheads in terms of number of online comparisons required for the memory deduplication. In this paper, we propose a static memory deduplication (SMD) technique which can reduce memory capacity requirement and provide performance optimization in cloud computing. The main innovation of SMD is that the process of page detection is performed offline, thus potentially reducing the performance cost, especially in terms of response time. In SMD, page comparisons are restricted to the code segment, which has the highest shared content. Our experimental results show that SMD efficiently reduces memory capacity requirement and improves performance. We demonstrate that, compared to other approaches, the cost in terms of the response time is negligible.

Multiway simple cycle separators and I/O-efficient algorithms for planar graphs

DEFF Research Database (Denmark)

Arge, L.; Walderveen, Freek van; Zeh, Norbert

2013-01-01

memory, where sort(N) is the number of I/Os needed to sort N items in external memory. The key, and the main technical contribution of this paper, is a multiway version of Miller's simple cycle separator theorem. We show how to compute these separators in linear time in internal memory, and using O...... in internal memory, thereby completely negating the performance gain achieved by minimizing the number of disk accesses. In this paper, we show how to make these algorithms simultaneously efficient in internal and external memory so they achieve I/O complexity O(sort(N)) and take O(N log N) time in internal......(sort(N)) I/Os and O(N log N) (internal-memory computation) time in external memory....

3D integration of planar crossbar memristive devices with CMOS substrate

International Nuclear Information System (INIS)

Lin, Peng; Pi, Shuang; Xia, Qiangfei

2014-01-01

Planar memristive devices with bottom electrodes embedded into the substrates were integrated on top of CMOS substrates using nanoimprint lithography to implement hybrid circuits with a CMOL-like architecture. The planar geometry eliminated the mechanically and electrically weak parts, such as kinks in the top electrodes in a traditional crossbar structure, and allowed the use of thicker and thus less resistive metal wires as the bottom electrodes. Planar memristive devices integrated with CMOS have demonstrated much lower programing voltages and excellent switching uniformity. With the inclusion of the Moiré pattern, the integration process has sub-20 nm alignment accuracy, opening opportunities for 3D hybrid circuits in applications in the next generation of memory and unconventional computing. (paper)

The effects of experimental pain and induced optimism on working memory task performance.

Science.gov (United States)

Boselie, Jantine J L M; Vancleef, Linda M G; Peters, Madelon L

2016-07-01

Pain can interrupt and deteriorate executive task performance. We have previously shown that experimentally induced optimism can diminish the deteriorating effect of cold pressor pain on a subsequent working memory task (i.e., operation span task). In two successive experiments we sought further evidence for the protective role of optimism on pain-induced working memory impairments. We used another working memory task (i.e., 2-back task) that was performed either after or during pain induction. Study 1 employed a 2 (optimism vs. no-optimism)×2 (pain vs. no-pain)×2 (pre-score vs. post-score) mixed factorial design. In half of the participants optimism was induced by the Best Possible Self (BPS) manipulation, which required them to write and visualize about a life in the future where everything turned out for the best. In the control condition, participants wrote and visualized a typical day in their life (TD). Next, participants completed either the cold pressor task (CPT) or a warm water control task (WWCT). Before (baseline) and after the CPT or WWCT participants working memory performance was measured with the 2-back task. The 2-back task measures the ability to monitor and update working memory representation by asking participants to indicate whether the current stimulus corresponds to the stimulus that was presented 2 stimuli ago. Study 2 had a 2 (optimism vs. no-optimism)×2 (pain vs. no-pain) mixed factorial design. After receiving the BPS or control manipulation, participants completed the 2-back task twice: once with painful heat stimulation, and once without any stimulation (counter-balanced order). Continuous heat stimulation was used with temperatures oscillating around 1°C above and 1°C below the individual pain threshold. In study 1, the results did not show an effect of cold pressor pain on subsequent 2-back task performance. Results of study 2 indicated that heat pain impaired concurrent 2-back task performance. However, no evidence was found

Flash memories economic principles of performance, cost and reliability optimization

CERN Document Server

Richter, Detlev

2014-01-01

The subject of this book is to introduce a model-based quantitative performance indicator methodology applicable for performance, cost and reliability optimization of non-volatile memories. The complex example of flash memories is used to introduce and apply the methodology. It has been developed by the author based on an industrial 2-bit to 4-bit per cell flash development project. For the first time, design and cost aspects of 3D integration of flash memory are treated in this book. Cell, array, performance and reliability effects of flash memories are introduced and analyzed. Key performance parameters are derived to handle the flash complexity. A performance and array memory model is developed and a set of performance indicators characterizing architecture, cost and durability is defined.   Flash memories are selected to apply the Performance Indicator Methodology to quantify design and technology innovation. A graphical representation based on trend lines is introduced to support a requirement based pr...

Optimization of External Envelope Insulation Thickness: A Parametric Study

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Eleftheria Touloupaki

2017-02-01

Full Text Available Almost four years after the implementation deadline of the energy performance of buildings Directive recast (2010/31/EU and after being referred to the Court of Justice of the EU by the European Commission, Greece has not yet proceeded with the necessary calculations and legislative measures on the minimum, cost-optimal energy performance requirements for buildings. This paper aims to identify the optimal thickness of insulation that is cost-effective to apply in urban multi-family domestic buildings in the four climate zones of Greece. A reference building is selected in order to perform calculations over ten scenarios of external insulation thickness for each climate zone on a basic and three sensitivity analysis calculations according to the EU comparative methodology framework. The resulting energy savings for each insulation scenario are calculated, and then the cost-effectiveness of the measure is examined in financial and macroeconomic perspective for an economic lifecycle of 30 years. The results demonstrate the inadequacy of the national regulation’s current insulation limits and the externalities (funding gaps that need to be addressed in order to achieve the effective improvement of energy efficiency in Greek homes.

External locus of control contributes to racial disparities in memory and reasoning training gains in ACTIVE.

Science.gov (United States)

Zahodne, Laura B; Meyer, Oanh L; Choi, Eunhee; Thomas, Michael L; Willis, Sherry L; Marsiske, Michael; Gross, Alden L; Rebok, George W; Parisi, Jeanine M

2015-09-01

Racial disparities in cognitive outcomes may be partly explained by differences in locus of control. African Americans report more external locus of control than non-Hispanic Whites, and external locus of control is associated with poorer health and cognition. The aims of this study were to compare cognitive training gains between African American and non-Hispanic White participants in the Advanced Cognitive Training for Independent and Vital Elderly (ACTIVE) study and determine whether racial differences in training gains are mediated by locus of control. The sample comprised 2,062 (26% African American) adults aged 65 and older who participated in memory, reasoning, or speed training. Latent growth curve models evaluated predictors of 10-year cognitive trajectories separately by training group. Multiple group modeling examined associations between training gains and locus of control across racial groups. Compared to non-Hispanic Whites, African Americans evidenced less improvement in memory and reasoning performance after training. These effects were partially mediated by locus of control, controlling for age, sex, education, health, depression, testing site, and initial cognitive ability. African Americans reported more external locus of control, which was associated with smaller training gains. External locus of control also had a stronger negative association with reasoning training gain for African Americans than for Whites. No racial difference in training gain was identified for speed training. Future intervention research with African Americans should test whether explicitly targeting external locus of control leads to greater cognitive improvement following cognitive training. (c) 2015 APA, all rights reserved).

Optimal energy window setting depending on the energy resolution for radionuclides used in gamma camera imaging. Planar imaging evaluation

International Nuclear Information System (INIS)

Kojima, Akihiro; Watanabe, Hiroyuki; Arao, Yuichi; Kawasaki, Masaaki; Takaki, Akihiro; Matsumoto, Masanori

2007-01-01

In this study, we examined whether the optimal energy window (EW) setting depending on an energy resolution of a gamma camera, which we previously proposed, is valid on planar scintigraphic imaging using Tl-201, Ga-67, Tc-99m, and I-123. Image acquisitions for line sources and paper sheet phantoms containing each radionuclide were performed in air and with scattering materials. For the six photopeaks excluding the Hg-201 characteristic x-rays' one, the conventional 20%-width energy window (EW20%) setting and the optimal energy window (optimal EW) setting (15%-width below 100 keV and 13%-width above 100 keV) were compared. For the Hg-201 characteristic x-rays' photopeak, the conventional on-peak EW20% setting was compared with the off-peak EW setting (73 keV-25%) and the wider off-peak EW setting (77 keV-29%). Image-count ratio (defined as the ratio of the image counts obtained with an EW and the total image counts obtained with the EW covered the whole photopeak for a line source in air), image quality, spatial resolutions (full width half maximum (FWHM) and full width tenth maximum (FWTM) values), count-profile curves, and defect-contrast values were compared between the conventional EW setting and the optimal EW setting. Except for the Hg-201 characteristic x-rays, the image-count ratios were 94-99% for the EW20% setting, but 78-89% for the optimal EW setting. However, the optimal EW setting reduced scatter fraction (defined as the scattered-to-primary counts ratio) effectively, as compared with the EW20% setting. Consequently, all the images with the optimal EW setting gave better image quality than ones with the EW20% setting. For the Hg-201 characteristic x-rays, the off-peak EW setting showed great improvement in image quality in comparison with the EW20% setting and the wider off-peak EW setting gave the best results. In conclusion, from our planar imaging study it was shown that although the optimal EW setting proposed by us gives less image-count ratio by

A method for aggregating external operating conditions in multi-generation system optimization models

DEFF Research Database (Denmark)

Lythcke-Jørgensen, Christoffer Ernst; Münster, Marie; Ensinas, Adriano Viana

2016-01-01

This paper presents a novel, simple method for reducing external operating condition datasets to be used in multi-generation system optimization models. The method, called the Characteristic Operating Pattern (CHOP) method, is a visually-based aggregation method that clusters reference data based...... on parameter values rather than time of occurrence, thereby preserving important information on short-term relations between the relevant operating parameters. This is opposed to commonly used methods where data are averaged over chronological periods (months or years), and extreme conditions are hidden...... in the averaged values. The CHOP method is tested in a case study where the operation of a fictive Danish combined heat and power plant is optimized over a historical 5-year period. The optimization model is solved using the full external operating condition dataset, a reduced dataset obtained using the CHOP...

A planar and tunable bandpass filter on a ferrite substrate with integrated windings

KAUST Repository

Arabi, Eyad A.

2015-05-01

Tunable Filters that are based on ferrite materials are often biased by external magnets or coils which are large and bulky. In this work a completely planar, CPW-based bandpass filter is presented with integrated windings. Due to these windings the size of the filter is only 26mm × 34mm × 0.38mm which is orders of magnitude smaller than the traditional designs with external windings. The filter is realized by electroplating of Copper over seed layers of Titanium and Gold over a YIG substrate. The fabricated filter achieves a tunability of 3.4% without any external magnets or coils. A good insertion loss of 2.3 dBs and rejection greater than 50 dBs have been obtained. To the best of the authors knowledge, this design is the first ferrite-based design that is completely planar and self-biased.

Approximation by planar elastic curves

DEFF Research Database (Denmark)

Brander, David; Gravesen, Jens; Nørbjerg, Toke Bjerge

2016-01-01

We give an algorithm for approximating a given plane curve segment by a planar elastic curve. The method depends on an analytic representation of the space of elastic curve segments, together with a geometric method for obtaining a good initial guess for the approximating curve. A gradient......-driven optimization is then used to find the approximating elastic curve....

The Role of Semantic Clustering in Optimal Memory Foraging

Science.gov (United States)

Montez, Priscilla; Thompson, Graham; Kello, Christopher T.

2015-01-01

Recent studies of semantic memory have investigated two theories of optimal search adopted from the animal foraging literature: Lévy flights and marginal value theorem. Each theory makes different simplifying assumptions and addresses different findings in search behaviors. In this study, an experiment is conducted to test whether clustering in…

Parameter optimization for transitions between memory states in small arrays of Josephson junctions

Energy Technology Data Exchange (ETDEWEB)

Rezac, Jacob D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Computer Science and Mathematics Division; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Computing and Computational Sciences Directorate; Univ. of Delaware, Newark, DE (United States). Dept. of Mathematical Sciences; Imam, Neena [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Computing and Computational Sciences Directorate; Braiman, Yehuda [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Computer Science and Mathematics Division; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Computing and Computational Sciences Directorate; ; Univ. of Tennessee, Knoxville, TN (United States). Dept. of Mechanical, Aerospace, and Biomedical Engineering

2017-01-11

Coupled arrays of Josephson junctions possess multiple stable zero voltage states. Such states can store information and consequently can be utilized for cryogenic memory applications. Basic memory operations can be implemented by sending a pulse to one of the junctions and studying transitions between the states. In order to be suitable for memory operations, such transitions between the states have to be fast and energy efficient. Here in this article we employed simulated annealing, a stochastic optimization algorithm, to study parameter optimization of array parameters which minimizes times and energies of transitions between specifically chosen states that can be utilized for memory operations (Read, Write, and Reset). Simulation results show that such transitions occur with access times on the order of 10–100 ps and access energies on the order of 10^-19–5×10^-18 J. Numerical simulations are validated with approximate analytical results.

A parameters optimization method for planar joint clearance model and its application for dynamics simulation of reciprocating compressor

Science.gov (United States)

Hai-yang, Zhao; Min-qiang, Xu; Jin-dong, Wang; Yong-bo, Li

2015-05-01

In order to improve the accuracy of dynamics response simulation for mechanism with joint clearance, a parameter optimization method for planar joint clearance contact force model was presented in this paper, and the optimized parameters were applied to the dynamics response simulation for mechanism with oversized joint clearance fault. By studying the effect of increased clearance on the parameters of joint clearance contact force model, the relation of model parameters between different clearances was concluded. Then the dynamic equation of a two-stage reciprocating compressor with four joint clearances was developed using Lagrange method, and a multi-body dynamic model built in ADAMS software was used to solve this equation. To obtain a simulated dynamic response much closer to that of experimental tests, the parameters of joint clearance model, instead of using the designed values, were optimized by genetic algorithms approach. Finally, the optimized parameters were applied to simulate the dynamics response of model with oversized joint clearance fault according to the concluded parameter relation. The dynamics response of experimental test verified the effectiveness of this application.

Optimal Design and Tradeoff Analysis of Planar Transformer in High-Power DC–DC Converters

DEFF Research Database (Denmark)

Ouyang, Ziwei; Thomsen, Ole Cornelius; Andersen, Michael A. E.

2012-01-01

The trend toward high power density, high operating frequency, and low profile in power converters has exposed a number of limitations in the use of conventional wire-wound magnetic component structures. A planar magnetic is a low-profile transformer or inductor utilizing planar windings, instead...... of the traditional windings made of Cu wires. In this paper, the most important factors for planar transformer (PT) design including winding loss, core loss, leakage inductance, and stray capacitance have individually been investigated. The tradeoffs among these factors have to be analyzed in order to achieve...

External costs in the global energy optimization models. A tool in favour of sustain ability

International Nuclear Information System (INIS)

Cabal Cuesta, H.

2007-01-01

The aim of this work is the analysis of the effects of the GHG external costs internalization in the energy systems. This may provide a useful tool to support decision makers to help reaching the energy systems sustain ability. External costs internalization has been carried out using two methods. First, CO 2 externalities of different power generation technologies have been internalized to evaluate their effects on the economic competitiveness of these present and future technologies. The other method consisted of analysing and optimizing the global energy system, from an economic and environmental point of view, using the global energy optimization model generator, TIMES, with a time horizon of 50 years. Finally, some scenarios regarding environmental and economic strategic measures have been analysed. (Author)

Optimal distance of an external focus of attention in standing long jump performance of athletes

Directory of Open Access Journals (Sweden)

Gh. Lotfi

2018-06-01

Full Text Available Background and Study Aim: Recently, studies have shown that an external focus of attention improves the performance of individuals. Some studies have also confirmed the superiority of distances away from body for external focus of attention. The aim of this study was to determine the optimal distance of an external focus of attention when performing athletes' standing long jump. Material and Method: 51 volunteer students (M age= 23.31 ± 5.26 years were selected as sample. At first all they performed a standing long jump in control status (without instruction for focus of attention. Then in an interpersonal counterbalanced design, a pair of jumps was performed with four different distances of an external focus of attention. These distances included 0.5, 2.5, 4 and 8 meters from the jump start line marked with colored tapes on the ground. Results: The results showed that having an external focus of attention compare to the control conditions has a significant advantage in the performance of the athlete's standing long jump. Also, the performance of athletes at different distances of an external focus of attention was compared. Results showed that the four-meter distance was significantly better performance than the half-meter distance of an external focus of attention. Conclusion: Four-meter distance can be introduced as the optimal distance of an external focus of attention in the performance of athletes’ standing long jump.

A QQ→QQ planar double box in canonical form

Directory of Open Access Journals (Sweden)

Marco S. Bianchi

2018-02-01

Full Text Available We consider a planar double box with four massive external momenta and two massive internal propagators. We derive the system of differential equations for the relevant master integrals, cast it in canonical form, write it as a dlog form and solve it in terms of iterated integrals up to depth four.

Computational Study on a PTAS for Planar Dominating Set Problem

Directory of Open Access Journals (Sweden)

Qian-Ping Gu

2013-01-01

Full Text Available The dominating set problem is a core NP-hard problem in combinatorial optimization and graph theory, and has many important applications. Baker [JACM 41,1994] introduces a k-outer planar graph decomposition-based framework for designing polynomial time approximation scheme (PTAS for a class of NP-hard problems in planar graphs. It is mentioned that the framework can be applied to obtain an O(2ckn time, c is a constant, (1+1/k-approximation algorithm for the planar dominating set problem. We show that the approximation ratio achieved by the mentioned application of the framework is not bounded by any constant for the planar dominating set problem. We modify the application of the framework to give a PTAS for the planar dominating set problem. With k-outer planar graph decompositions, the modified PTAS has an approximation ratio (1 + 2/k. Using 2k-outer planar graph decompositions, the modified PTAS achieves the approximation ratio (1+1/k in O(22ckn time. We report a computational study on the modified PTAS. Our results show that the modified PTAS is practical.

Topology Optimization of Shape Memory Alloy Actuators using Element Connectivity Parameterization

DEFF Research Database (Denmark)

Langelaar, Matthijs; Yoon, Gil Ho; Kim, Yoon Young

2005-01-01

This paper presents the first application of topology optimization to the design of shape memory alloy actuators. Shape memory alloys (SMA’s) exhibit strongly nonlinear, temperature-dependent material behavior. The complexity in the constitutive behavior makes the topology design of SMA structure......) stiffness matrix of continuum finite elements. Therefore, any finite element code, including commercial codes, can be readily used for the ECP implementation. The key ideas and characteristics of these methods will be presented in this paper....

A study of coFeB magnetic yoke based on planar electromagnet

Science.gov (United States)

Qin, L.; Li, Q.; Yuan, Yong J.

2017-07-01

This paper studies the fabrication of a novel planar electromagnet consisting of a planar copper coil and a magnetic yoke. CoFeB was used as the magnetic yoke material instead of the traditional permanent magnets. The planar electromagnet was fabricated and optimized to maximize the electromagnetic force, especially with varying CoFeB thickness. The micro-planar electromagnet was fabricated successfully by the traditional micro-electro-mechanical-system (MEMS) techniques and XRD, VSM were used to characterize the performance of the electromagnet. The planar electromagnet exhibits superior perpendicular magnetic anisotropy (PMA) and 0.006 emu of MS was achieved following 2 min deposition of CoFeB thin film. By integrating with other micro apparatuses, it is anticipated that the planar electromagnet will have potential applications in areas such as biosensors, biological medicine, drug delivery, chemical analysis and environmental monitoring.

Application of holographic elements in displays and planar illuminators

Science.gov (United States)

Putilin, Andrew; Gustomiasov, Igor

2007-05-01

Holographic Optical Elements (HOE's) on planar waveguides can be used to design the planar optics for backlit units, color selectors or filters, lenses for virtual reality displays. The several schemes for HOE recording are proposed to obtain planar stereo backlit unit and private eye displays light source. It is shown in the paper that the specific light transformation grating permits to construct efficient backlit units for display holograms and LCD. Several schemes of reflection/transmission backlit units and scattering films based on holographic optical elements are also proposed. The performance of the waveguide HOE can be optimized using the parameters of recording scheme and etching parameters. The schemes of HOE application are discussed and some experimental results are shown.

Method for refreshing a non-volatile memory

Science.gov (United States)

Riekels, James E.; Schlesinger, Samuel

2008-11-04

A non-volatile memory and a method of refreshing a memory are described. The method includes allowing an external system to control refreshing operations within the memory. The memory may generate a refresh request signal and transmit the refresh request signal to the external system. When the external system finds an available time to process the refresh request, the external system acknowledges the refresh request and transmits a refresh acknowledge signal to the memory. The memory may also comprise a page register for reading and rewriting a data state back to the memory. The page register may comprise latches in lieu of supplemental non-volatile storage elements, thereby conserving real estate within the memory.

Estimating location without external cues.

Directory of Open Access Journals (Sweden)

Allen Cheung

2014-10-01

Full Text Available The ability to determine one's location is fundamental to spatial navigation. Here, it is shown that localization is theoretically possible without the use of external cues, and without knowledge of initial position or orientation. With only error-prone self-motion estimates as input, a fully disoriented agent can, in principle, determine its location in familiar spaces with 1-fold rotational symmetry. Surprisingly, localization does not require the sensing of any external cue, including the boundary. The combination of self-motion estimates and an internal map of the arena provide enough information for localization. This stands in conflict with the supposition that 2D arenas are analogous to open fields. Using a rodent error model, it is shown that the localization performance which can be achieved is enough to initiate and maintain stable firing patterns like those of grid cells, starting from full disorientation. Successful localization was achieved when the rotational asymmetry was due to the external boundary, an interior barrier or a void space within an arena. Optimal localization performance was found to depend on arena shape, arena size, local and global rotational asymmetry, and the structure of the path taken during localization. Since allothetic cues including visual and boundary contact cues were not present, localization necessarily relied on the fusion of idiothetic self-motion cues and memory of the boundary. Implications for spatial navigation mechanisms are discussed, including possible relationships with place field overdispersion and hippocampal reverse replay. Based on these results, experiments are suggested to identify if and where information fusion occurs in the mammalian spatial memory system.

Optimal Fare, Vacancy Rate, and Subsidies under Log-Linear Demand with the Consideration of Externalities for a Cruising Taxi Market

Directory of Open Access Journals (Sweden)

Chun-Hsiao Chu

2017-01-01

Full Text Available Externality is an important issue for formulating the regulation policy of a taxi market. However, this issue is rarely taken into account in the current policy-making process, and it has not been adequately explored in prior research. This study extends the model proposed by Chang and Chu in 2009 with the aim of exploring the effect of externality on the optimization of the regulation policy of a cruising taxi market. A closed-form solution for optimizing the fare, vacancy rate, and subsidy of the market is derived. The results show that when the externality of taxi trips is taken into consideration, the optimal vacancy rate should be lower and the subsidy should be higher than they are under current conditions where externality is not considered. The results of the sensitivity analysis on the occupied and vacant distance indicate that the relation of the vacant distance to the marginal external cost is more sensitive than the occupied distance. The result of the sensitivity analysis on the subsidy shows the existence of a negative relationship between the marginal external cost and the optimal subsidy.

Everyday experiences of memory problems and control: the adaptive role of selective optimization with compensation in the context of memory decline.

Science.gov (United States)

Hahn, Elizabeth A; Lachman, Margie E

2015-01-01

The present study examined the role of long-term working memory decline in the relationship between everyday experiences of memory problems and perceived control, and we also considered whether the use of accommodative strategies [selective optimization with compensation (SOC)] would be adaptive. The study included Boston-area participants (n = 103) from the Midlife in the United States study (MIDUS) who completed two working memory assessments over 10 years and weekly diaries following Time 2. In adjusted multi-level analyses, greater memory decline and lower general perceived control were associated with more everyday memory problems. Low perceived control reported in a weekly diary was associated with more everyday memory problems among those with greater memory decline and low SOC strategy use (Est. = -0.28, SE= 0.13, p = .036). These results suggest that the use of SOC strategies in the context of declining memory may help to buffer the negative effects of low perceived control on everyday memory.

A prologue to nostalgia: savouring creates nostalgic memories that foster optimism.

Science.gov (United States)

Biskas, Marios; Cheung, Wing-Yee; Juhl, Jacob; Sedikides, Constantine; Wildschut, Tim; Hepper, Erica

2018-04-02

How are nostalgic memories created? We considered savouring as one process involved in the genesis of nostalgia. Whereas nostalgia refers to an emotional reflection upon past experiences, savouring is a process in which individuals deeply attend to and consciously capture a present experience for subsequent reflection. Thus, having savoured an experience may increase the likelihood that it will later be reflected upon nostalgically. Additionally, to examine how cognitive and emotional processes are linked across time, we tested whether nostalgia for a previously savoured experience predicts optimism for the future. Retrospective reports of having savoured a positive event were associated with greater nostalgia for the event (Study 1). Retrospective reports of savouring a time period (college) were associated with greater nostalgia for that time period when participants were in a setting (alumni reunion event) that prompted thoughts of the time period (Study 2). Savouring an experience predicted nostalgia for the experience 4-9 months later (Study 3). Additionally, nostalgia was associated with greater optimism (Studies 2-3). Thus, savouring provides a foundation for nostalgic memories and an ensuing optimism.

Resistive switching effect in the planar structure of all-printed, flexible and rewritable memory device based on advanced 2D nanocomposite of graphene quantum dots and white graphene flakes

International Nuclear Information System (INIS)

Rehman, Muhammad Muqeet; Siddiqui, Ghayas Uddin; Kim, Sowon; Choi, Kyung Hyun

2017-01-01

Pursuit of the most appropriate materials and fabrication methods is essential for developing a reliable, rewritable and flexible memory device. In this study, we have proposed an advanced 2D nanocomposite of white graphene (hBN) flakes embedded with graphene quantum dots (GQDs) as the functional layer of a flexible memory device owing to their unique electrical, chemical and mechanical properties. Unlike the typical sandwich type structure of a memory device, we developed a cost effective planar structure, to simplify device fabrication and prevent sneak current. The entire device fabrication was carried out using printing technology followed by encapsulation in an atomically thin layer of aluminum oxide (Al 2 O 3 ) for protection against environmental humidity. The proposed memory device exhibited attractive bipolar switching characteristics of high switching ratio, large electrical endurance and enhanced lifetime, without any crosstalk between adjacent memory cells. The as-fabricated device showed excellent durability for several bending cycles at various bending diameters without any degradation in bistable resistive states. The memory mechanism was deduced to be conductive filamentary; this was validated by illustrating the temperature dependence of bistable resistive states. Our obtained results pave the way for the execution of promising 2D material based next generation flexible and non-volatile memory (NVM) applications. (paper)

Automated curved planar reformation of 3D spine images

International Nuclear Information System (INIS)

Vrtovec, Tomaz; Likar, Bostjan; Pernus, Franjo

2005-01-01

Traditional techniques for visualizing anatomical structures are based on planar cross-sections from volume images, such as images obtained by computed tomography (CT) or magnetic resonance imaging (MRI). However, planar cross-sections taken in the coordinate system of the 3D image often do not provide sufficient or qualitative enough diagnostic information, because planar cross-sections cannot follow curved anatomical structures (e.g. arteries, colon, spine, etc). Therefore, not all of the important details can be shown simultaneously in any planar cross-section. To overcome this problem, reformatted images in the coordinate system of the inspected structure must be created. This operation is usually referred to as curved planar reformation (CPR). In this paper we propose an automated method for CPR of 3D spine images, which is based on the image transformation from the standard image-based to a novel spine-based coordinate system. The axes of the proposed spine-based coordinate system are determined on the curve that represents the vertebral column, and the rotation of the vertebrae around the spine curve, both of which are described by polynomial models. The optimal polynomial parameters are obtained in an image analysis based optimization framework. The proposed method was qualitatively and quantitatively evaluated on five CT spine images. The method performed well on both normal and pathological cases and was consistent with manually obtained ground truth data. The proposed spine-based CPR benefits from reduced structural complexity in favour of improved feature perception of the spine. The reformatted images are diagnostically valuable and enable easier navigation, manipulation and orientation in 3D space. Moreover, reformatted images may prove useful for segmentation and other image analysis tasks

Exchange-biased planar Hall effect sensor optimized for biosensor applications

DEFF Research Database (Denmark)

Damsgaard, Christian Danvad; Freitas, S.C.; Freitas, P.P.

2008-01-01

This article presents experimental investigations of exchange-biased Permalloy planar Hall effect sensor crosses with a fixed active area of w x w = 40 x 40 mu m(2) and Permalloy thicknesses of t = 20, 30, and 50 nm. It is shown that a single domain model describes the system well...

A planar microfluidic mixer based on logarithmic spirals

International Nuclear Information System (INIS)

Scherr, Thomas; Nandakumar, Krishnaswamy; Quitadamo, Christian; Tesvich, Preston; Park, Daniel Sang-Won; Hayes, Daniel; Monroe, W Todd; Tiersch, Terrence; Choi, Jin-Woo

2012-01-01

A passive, planar micromixer design based on logarithmic spirals is presented. The device was fabricated using polydimethylsiloxane soft photolithography techniques, and mixing performance was characterized via numerical simulation and fluorescent microscopy. Mixing efficiency initially declined as the Reynolds number increased, and this trend continued until a Reynolds number of 15 where a minimum was reached at 53%. Mixing efficiency then began to increase reaching a maximum mixing efficiency of 86% at Re = 67. Three-dimensional (3D) simulations of fluid mixing in this design were compared to other planar geometries such as the Archimedes spiral and Meandering-S mixers. The implementation of logarithmic curvature offers several unique advantages that enhance mixing, namely a variable cross-sectional area and a logarithmically varying radius of curvature that creates 3D Dean vortices. These flow phenomena were observed in simulations with multilayered fluid folding and validated with confocal microscopy. This design provides improved mixing performance over a broader range of Reynolds numbers than other reported planar mixers, all while avoiding external force fields, more complicated fabrication processes and the introduction of flow obstructions or cavities that may unintentionally affect sensitive or particulate-containing samples. Due to the planar design requiring only single-step lithographic features, this compact geometry could be easily implemented into existing micro-total analysis systems requiring effective rapid mixing. (paper)

Planar Circularly Symmetric Electromagnetic Band-Gap Antennas for Low Cost High Performance Integrated Antennas

NARCIS (Netherlands)

Neto, A.; LLombart, N.; Gerini, G.; Maagt, P.J. de

2009-01-01

The use of Planar Circularly Symmetric (PCS) Electromagnetic Band-Gap (EBG) structures for optimizing the performances of single antenna elements and arrays is been discussed. The key advantage of using this sort of super structures is that they are planar and thus very cheap to manufacture with

Planar circularly symmetric Electromagnetic Band-Gap antennas for low cost high performance integrated antennas

NARCIS (Netherlands)

Neto, A.; Llombart, N.; Gerini, G.; de Maagt, P.J.I.

2009-01-01

The use of planar circularly symmetric (PCS) electromagnetic band-gap (EBG) structures for optimizing the performances of single antenna elements and arrays is been discussed. The key advantage of using this sort of super structures is that they are planar and thus very cheap to manufacture with

Numerical investigation of heat transfer characteristic of fixed planar elastic tube bundles

International Nuclear Information System (INIS)

Duan, Derong; Ge, Peiqi; Bi, Wenbo

2015-01-01

Highlights: • Both tube-side and shell-side of planar elastic tube bundles were investigated. • Heat transfer and fluid flow were studied from the local analysis perspective. • Secondary flow varies depending on the fluid flow state and the geometry of tube. • Curvature plays a role on the external flow field. • The heat transfer of the two intermediate tube bundles is augmented. - Abstract: Planar elastic tube bundles are a novel approach to enhance heat transfer by using flow-induced vibration. This paper studied the heat transfer characteristic and fluid flow in both tube-side and shell-side using numerical simulation. Two temperature difference formulas were used to calculate convective heat transfer coefficient and the results were verified by theoretical analysis and experimental correlations. The effect of Reynolds number on overall convective heat transfer coefficient and pressure drop in tube-side and shell-side were studied. The comparison of the secondary flow in planar elastic tube bundles and conical spiral tube bundles were conducted. The external flow field and local convective heat transfer around the periphery of fixed planar elastic tube bundles subjected to the cross fluid flow were also analyzed. The results show that the energy consumption efficiency should be taken into account in the forced heat transfer process conducted by adjusting the fluid flow. The secondary flow varies depending on the fluid flow state and the geometry of tube. Hence, it is deduced that the heat transfer enhancement is obtained because the thermal boundary layer in the deformed planar elastic tube bundles caused by flow-induced vibration is damaged by the disordered secondary flow. In addition, the convective heat transfer capability of outside the two intermediate tube bundles is enhanced because of the effect of irregular and complex fluid flow affected by the role of curved tubes on both sides

Growth and characterization of textured well-faceted ZnO on planar Si(100, planar Si(111, and textured Si(100 substrates for solar cell applications

Directory of Open Access Journals (Sweden)

Chin-Yi Tsai

2017-09-01

Full Text Available In this work, textured, well-faceted ZnO materials grown on planar Si(100, planar Si(111, and textured Si(100 substrates by low-pressure chemical vapor deposition (LPCVD were analyzed by X-ray diffraction (XRD, scanning electron microscopy (SEM, atomic force microscopy (AFM, and cathode luminescence (CL measurements. The results show that ZnO grown on planar Si(100, planar Si(111, and textured Si(100 substrates favor the growth of ZnO(110 ridge-like, ZnO(002 pyramid-like, and ZnO(101 pyramidal-tip structures, respectively. This could be attributed to the constraints of the lattice mismatch between the ZnO and Si unit cells. The average grain size of ZnO on the planar Si(100 substrate is slightly larger than that on the planar Si(111 substrate, while both of them are much larger than that on the textured Si(100 substrate. The average grain sizes (about 10–50 nm of the ZnO grown on the different silicon substrates decreases with the increase of their strains. These results are shown to strongly correlate with the results from the SEM, AFM, and CL as well. The reflectance spectra of these three samples show that the antireflection function provided by theses samples mostly results from the nanometer-scaled texture of the ZnO films, while the micrometer-scaled texture of the Si substrate has a limited contribution. The results of this work provide important information for optimized growth of textured and well-faceted ZnO grown on wafer-based silicon solar cells and can be utilized for efficiency enhancement and optimization of device materials and structures, such as heterojunction with intrinsic thin layer (HIT solar cells.

Inkjet-based adaptive planarization (Conference Presentation)

Science.gov (United States)

Singhal, Shrawan; Grigas, Michelle M.; Khusnatdinov, Niyaz; Sreenivasan, Srinivasan V.

2017-03-01

that should have been polished away. Preventive techniques like dummy fill and patterned resist can be used to reduce the variation in pattern density. These techniques increase the complexity of the planarization process and significantly limit the device design flexibility. Contact Planarization (CP) has also been reported as an alternative to the CMP processing [7], [8]. A substrate is spin coated with a photo curable material and pre baked to remove residual solvent. An ultra-flat surface or an optical flat is pressed on the spin-coated wafer. The material is forced to reflow. Pressure is used to spread out material evenly and achieve global planarization. The substrate is then exposed to UV radiation to harden the photo curable material. Although attractive, this process is not adaptive as it does not account for differences in surface topography of the wafer and the optical flat, nor can it address all the parasitics that arise during the process itself. The optical flat leads to undesirable planarization of even the substrate nominal shape and nanotopography, which corrupts the final film thickness profile. Hence, it becomes extremely difficult to eliminate this signature to a desirable extent without introducing other parasitic signatures. An example of this is shown in Figure 1. In this paper, a novel adaptive planarization process has been presented that potentially addresses the problems associated with planarization of varying pattern density, even in the presence of pre-existing substrate topography [9]. This process is called Inkjet-enabled Adaptive Planarization (IAP). The IAP process uses an inverse optimization scheme, built around a validated fluid mechanics-based forward model [10], that takes the pre-existing substrate topography and pattern layout as inputs. It then generates an inkjet drop pattern with a material distribution that is correlated with the desired planarization film profile. This allows a contiguous film to be formed with the desired

Decision theory, motor planning, and visual memory: deciding where to reach when memory errors are costly.

Science.gov (United States)

Lerch, Rachel A; Sims, Chris R

2016-06-01

Limitations in visual working memory (VWM) have been extensively studied in psychophysical tasks, but not well understood in terms of how these memory limits translate to performance in more natural domains. For example, in reaching to grasp an object based on a spatial memory representation, overshooting the intended target may be more costly than undershooting, such as when reaching for a cup of hot coffee. The current body of literature lacks a detailed account of how the costs or consequences of memory error influence what we encode in visual memory and how we act on the basis of remembered information. Here, we study how externally imposed monetary costs influence behavior in a motor decision task that involves reach planning based on recalled information from VWM. We approach this from a decision theoretic perspective, viewing decisions of where to aim in relation to the utility of their outcomes given the uncertainty of memory representations. Our results indicate that subjects accounted for the uncertainty in their visual memory, showing a significant difference in their reach planning when monetary costs were imposed for memory errors. However, our findings indicate that subjects memory representations per se were not biased by the imposed costs, but rather subjects adopted a near-optimal post-mnemonic decision strategy in their motor planning.

Two-Loop Master Integrals for $\\gamma^{*} \\to 3$ Jets the Non-Planar Topologies

CERN Document Server

Gehrmann, T

2001-01-01

The calculation of the two-loop corrections to the three-jet production rate and to event shapes in electron--positron annihilation requires the computation of a number of two-loop four-point master integrals with one off-shell and three on-shell legs. Up to now, only those master integrals corresponding to planar topologies were known. In this paper, we compute the yet outstanding non-planar master integrals by solving differential equations in the external invariants which are fulfilled by these master integrals. We obtain the master integrals as expansions in $\\e=(4-d)/2$, where $d$ is the space-time dimension. The fully analytic results are expressed in terms of the two-dimensional harmonic polylogarithms already introduced in the evaluation of the planar topologies.

Validation of an activity optimization method for nuclear medicine in planar studies

Energy Technology Data Exchange (ETDEWEB)

Perez D, M. [Central University of Las Villas, CEETI, Camajuani Road Km 5.5, Santa Clara 54830 Villa Clara (Cuba); Diaz R, O. [Institute for Sciences and Advanced Technologies (Cuba); Farias L, F. [Federal University of Pernambuco (Brazil)]. e-mail: mperez@uclv.edu.cu

2006-07-01

A method for optimizing the administered activity in Static Nuclear Medicine Studies is validated by comparison with ROC curve. Linear Discriminant analysis of image quality in gamma cameras was the applied statistical technique. The constructed linear discriminant function owns as dependent parameters, the differentiated levels of image quality obtained by observer's criterion. The independent parameters in the function were physical variables, as Signal-to Background ratios and Signal-to-Noise ratios. They were obtained from the selection of Regions of Interest in images obtained from a Jaszczak phantom, corresponding to lesion and background sites. The percentage of cases correctly classified by discriminant analysis was analyzed to grade the proposed discriminant method. The minimum value of the administered activity, which permits good image quality, (it means good results for the parameters selected by the discriminant function), can be proposed as an optimized value of activity for planar studies of Nuclear Medicine. The method was tested using images from a Jaszczak phantom, acquired under four activities (1088 MBq, 962 MBq, 740 MBq and 562 MBq) with a gamma camera equipped with a high resolution - low energy- parallel-hole collimator. The gamma camera was tested by a NEMA protocol. Image quality was graded by three expert observers who also developed a rated procedure which consist in analyzing the images for ROC analysis. Two of the six measured Background-to-Signal ratios were the parameters able to construct the linear discriminant function with high correlation respect to the observer criterion, from all the measured physical variables. The value of 740 MBq was the optimum after discriminant method application in this particular experiment. The results were coincident with the application of ROC-analysis. The optimal activity value obtained with the proposed discriminant procedure coincided with the activity value for which the area under the ROC

Caffeine Enhances Memory Performance in Young Adults during Their Non-optimal Time of Day.

Science.gov (United States)

Sherman, Stephanie M; Buckley, Timothy P; Baena, Elsa; Ryan, Lee

2016-01-01

Many college students struggle to perform well on exams in the early morning. Although students drink caffeinated beverages to feel more awake, it is unclear whether these actually improve performance. After consuming coffee (caffeinated or decaffeinated), college-age adults completed implicit and explicit memory tasks in the early morning and late afternoon (Experiment 1). During the morning, participants ingesting caffeine demonstrated a striking improvement in explicit memory, but not implicit memory. Caffeine did not alter memory performance in the afternoon. In Experiment 2, participants engaged in cardiovascular exercise in order to examine whether increases in physiological arousal similarly improved memory. Despite clear increases in physiological arousal, exercise did not improve memory performance compared to a stretching control condition. These results suggest that caffeine has a specific benefit for memory during students' non-optimal time of day - early morning. These findings have real-world implications for students taking morning exams.

Multistability in planar liquid crystal wells

KAUST Repository

Luo, Chong

2012-06-08

A planar bistable liquid crystal device, reported in Tsakonas, is modeled within the Landau-de Gennes theory for nematic liquid crystals. This planar device consists of an array of square micrometer-sized wells. We obtain six different classes of equilibrium profiles and these profiles are classified as diagonal or rotated solutions. In the strong anchoring case, we propose a Dirichlet boundary condition that mimics the experimentally imposed tangent boundary conditions. In the weak anchoring case, we present a suitable surface energy and study the multiplicity of solutions as a function of the anchoring strength. We find that diagonal solutions exist for all values of the anchoring strength W≥0, while rotated solutions only exist for W≥W c>0, where W c is a critical anchoring strength that has been computed numerically. We propose a dynamic model for the switching mechanisms based on only dielectric effects. For sufficiently strong external electric fields, we numerically demonstrate diagonal-to-rotated and rotated-to-diagonal switching by allowing for variable anchoring strength across the domain boundary. © 2012 American Physical Society.

Multistability in planar liquid crystal wells

KAUST Repository

Luo, Chong; Majumdar, Apala; Erban, Radek

2012-01-01

A planar bistable liquid crystal device, reported in Tsakonas, is modeled within the Landau-de Gennes theory for nematic liquid crystals. This planar device consists of an array of square micrometer-sized wells. We obtain six different classes of equilibrium profiles and these profiles are classified as diagonal or rotated solutions. In the strong anchoring case, we propose a Dirichlet boundary condition that mimics the experimentally imposed tangent boundary conditions. In the weak anchoring case, we present a suitable surface energy and study the multiplicity of solutions as a function of the anchoring strength. We find that diagonal solutions exist for all values of the anchoring strength W≥0, while rotated solutions only exist for W≥W c>0, where W c is a critical anchoring strength that has been computed numerically. We propose a dynamic model for the switching mechanisms based on only dielectric effects. For sufficiently strong external electric fields, we numerically demonstrate diagonal-to-rotated and rotated-to-diagonal switching by allowing for variable anchoring strength across the domain boundary. © 2012 American Physical Society.

Effect of Annealing Process on CH3NH3PbI3-XClX Film Morphology of Planar Heterojunction Perovskite Solar Cells with Optimal Compact TiO2 Layer

Directory of Open Access Journals (Sweden)

Dan Chen

2017-01-01

Full Text Available The morphology of compact TiO2 film used as an electron-selective layer and perovskite film used as a light absorption layer in planar perovskite solar cells has a significant influence on the photovoltaic performance of the devices. In this paper, the spin coating speed of the compact TiO2 is investigated in order to get a high-quality film and the compact TiO2 film exhibits pinhole- and crack-free films treated by 2000 rpm for 60 s. Furthermore, the effect of annealing process, including annealing temperature and annealing program, on CH3NH3PbI3-XClX film morphology is studied. At the optimal annealing temperature of 100°C, the CH3NH3PbI3-XClX morphology fabricated by multistep slow annealing method has smaller grain boundaries and holes than that prepared by one-step direct annealing method, which results in the reduction of grain boundary recombination and the increase of Voc. With all optimal procedures, a planar fluorine-doped tin oxide (FTO substrate/compact TiO2/CH3NH3PbI3-XClX/Spiro-MeOTAD/Au cell is prepared for an active area of 0.1 cm2. It has achieved a power conversion efficiency (PCE of 14.64%, which is 80.3% higher than the reference cell (8.12% PCE without optimal perovskite layer. We anticipate that the annealing process with optimal compact TiO2 layer would possibly become a promising method for future industrialization of planar perovskite solar cells.

Quantum memory for Rindler supertranslations

Science.gov (United States)

Kolekar, Sanved; Louko, Jorma

2018-04-01

The Rindler horizon in Minkowski spacetime can be implanted with supertranslation hair by a matter shock wave without planar symmetry, and the hair is observable as a supertranslation memory on the Rindler family of uniformly linearly accelerated observers. We show that this classical memory is accompanied by a supertranslation quantum memory that modulates the entanglement between the opposing Rindler wedges in quantum field theory. A corresponding phenomenon across a black hole horizon may play a role in Hawking, Perry, and Strominger's proposal for supertranslations to provide a solution to the black hole information paradox.

Accessing memory

Science.gov (United States)

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

2017-09-26

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

Planar Hall Effect Sensors for Biodetection

DEFF Research Database (Denmark)

Rizzi, Giovanni

. In the second geometry (dPHEB) half of the sensor is used as a local negative reference to subtract the background signal from magnetic beads in suspension. In all applications below, the magnetic beads are magnetised using the magnetic field due to the bias current passed through the sensor, i.e., no external...... as labels and planar Hall effect bridge (PHEB) magnetic field sensor as readout for the beads. The choice of magnetic beads as label is motivated by the lack of virtually any magnetic background from biological samples. Moreover, magnetic beads can be manipulated via an external magnetic field...... hybridisation in real-time, in a background of suspended magnetic beads. This characteristic is employed in single nucleotide polymorphism (SNP) genotyping, where the denaturation of DNA is monitored in real-time upon washing with a stringency buffer. The sensor setup includes temperature control and a fluidic...

Caffeine enhances memory performance in young adults during their non-optimal time of day

Directory of Open Access Journals (Sweden)

Stephanie M Sherman

2016-11-01

Full Text Available Many college students struggle to perform well on exams in the early morning. Although students drink caffeinated beverages to feel more awake, it is unclear whether these actually improve performance. After consuming coffee (caffeinated or decaffeinated, college-age adults completed implicit and explicit memory tasks in the early morning and late afternoon (Experiment 1. During the morning, participants ingesting caffeine demonstrated a striking improvement in explicit memory, but not implicit memory. Caffeine did not alter memory performance in the afternoon. In Experiment 2, participants engaged in cardiovascular exercise in order to examine whether increases in physiological arousal similarly improved memory. Despite clear increases in arousal, exercise did not improve memory performance compared to a stretching control condition. These results suggest that caffeine has a specific benefit for memory during students’ non-optimal time of day – early morning. These findings have real-world implications for students taking morning exams.

Analysis and Optimization of Four-Coil Planar Magnetically Coupled Printed Spiral Resonators

Directory of Open Access Journals (Sweden)

Sadeque Reza Khan

2016-08-01

Full Text Available High-efficiency power transfer at a long distance can be efficiently established using resonance-based wireless techniques. In contrast to the conventional two-coil-based inductive links, this paper presents a magnetically coupled fully planar four-coil printed spiral resonator-based wireless power-transfer system that compensates the adverse effect of low coupling and improves efficiency by using high quality-factor coils. A conformal architecture is adopted to reduce the transmitter and receiver sizes. Both square architecture and circular architectures are analyzed and optimized to provide maximum efficiency at a certain operating distance. Furthermore, their performance is compared on the basis of the power-transfer efficiency and power delivered to the load. Square resonators can produce higher measured power-transfer efficiency (79.8% than circular resonators (78.43% when the distance between the transmitter and receiver coils is 10 mm of air medium at a resonant frequency of 13.56 MHz. On the other hand, circular coils can deliver higher power (443.5 mW to the load than the square coils (396 mW under the same medium properties. The performance of the proposed structures is investigated by simulation using a three-layer human-tissue medium and by experimentation.

Analysis and Optimization of Four-Coil Planar Magnetically Coupled Printed Spiral Resonators.

Science.gov (United States)

Khan, Sadeque Reza; Choi, GoangSeog

2016-08-03

High-efficiency power transfer at a long distance can be efficiently established using resonance-based wireless techniques. In contrast to the conventional two-coil-based inductive links, this paper presents a magnetically coupled fully planar four-coil printed spiral resonator-based wireless power-transfer system that compensates the adverse effect of low coupling and improves efficiency by using high quality-factor coils. A conformal architecture is adopted to reduce the transmitter and receiver sizes. Both square architecture and circular architectures are analyzed and optimized to provide maximum efficiency at a certain operating distance. Furthermore, their performance is compared on the basis of the power-transfer efficiency and power delivered to the load. Square resonators can produce higher measured power-transfer efficiency (79.8%) than circular resonators (78.43%) when the distance between the transmitter and receiver coils is 10 mm of air medium at a resonant frequency of 13.56 MHz. On the other hand, circular coils can deliver higher power (443.5 mW) to the load than the square coils (396 mW) under the same medium properties. The performance of the proposed structures is investigated by simulation using a three-layer human-tissue medium and by experimentation.

High Current Planar Transformer for Very High Efficiency Isolated Boost DC-DC Converters

DEFF Research Database (Denmark)

Pittini, Riccardo; Zhang, Zhe; Andersen, Michael A. E.

2014-01-01

This paper presents a design and optimization of a high current planar transformer for very high efficiency dc-dc isolated boost converters. The analysis considers different winding arrangements, including very high copper thickness windings. The analysis is focused on the winding ac-resistance a......This paper presents a design and optimization of a high current planar transformer for very high efficiency dc-dc isolated boost converters. The analysis considers different winding arrangements, including very high copper thickness windings. The analysis is focused on the winding ac......-resistance and transformer leakage inductance. Design and optimization procedures are validated based on an experimental prototype of a 6 kW dcdc isolated full bridge boost converter developed on fully planar magnetics. The prototype is rated at 30-80 V 0-80 A on the low voltage side and 700-800 V on the high voltage side...... with a peak efficiency of 97.8% at 80 V 3.5 kW. Results highlights that thick copper windings can provide good performance at low switching frequencies due to the high transformer filling factor. PCB windings can also provide very high efficiency if stacked in parallel utilizing the transformer winding window...

APL/MITRA-15, concept of a virtual memory, optimization, generalized arrays

International Nuclear Information System (INIS)

Nevians, Jacques

1975-01-01

The aim of this work was to implement of an A.P.L. interpreter on a mini computer, specifically on a MITRA 15. Main topics are about dynamic allocation of the memory with a virtual memory system. The original aspect of these two systems is based on the qualities of the language which has permitted a modular and performing programming (allocating function... function of access). A study of the optimization of a certain number of primitives has been undertaken and developed (for example the J-Vectors). Moreover, the notion of structure (generalized arrays) has been introduced by the programming of some new primitives. (author) [fr

Rapid Optimization of External Quantum Efficiency of Thin Film Solar Cells Using Surrogate Modeling of Absorptivity.

Science.gov (United States)

Kaya, Mine; Hajimirza, Shima

2018-05-25

This paper uses surrogate modeling for very fast design of thin film solar cells with improved solar-to-electricity conversion efficiency. We demonstrate that the wavelength-specific optical absorptivity of a thin film multi-layered amorphous-silicon-based solar cell can be modeled accurately with Neural Networks and can be efficiently approximated as a function of cell geometry and wavelength. Consequently, the external quantum efficiency can be computed by averaging surrogate absorption and carrier recombination contributions over the entire irradiance spectrum in an efficient way. Using this framework, we optimize a multi-layer structure consisting of ITO front coating, metallic back-reflector and oxide layers for achieving maximum efficiency. Our required computation time for an entire model fitting and optimization is 5 to 20 times less than the best previous optimization results based on direct Finite Difference Time Domain (FDTD) simulations, therefore proving the value of surrogate modeling. The resulting optimization solution suggests at least 50% improvement in the external quantum efficiency compared to bare silicon, and 25% improvement compared to a random design.

Topology optimized and 3D printed polymer-bonded permanent magnets for a predefined external field

Science.gov (United States)

Huber, C.; Abert, C.; Bruckner, F.; Pfaff, C.; Kriwet, J.; Groenefeld, M.; Teliban, I.; Vogler, C.; Suess, D.

2017-08-01

Topology optimization offers great opportunities to design permanent magnetic systems that have specific external field characteristics. Additive manufacturing of polymer-bonded magnets with an end-user 3D printer can be used to manufacture permanent magnets with structures that had been difficult or impossible to manufacture previously. This work combines these two powerful methods to design and manufacture permanent magnetic systems with specific properties. The topology optimization framework is simple, fast, and accurate. It can also be used for the reverse engineering of permanent magnets in order to find the topology from field measurements. Furthermore, a magnetic system that generates a linear external field above the magnet is presented. With a volume constraint, the amount of magnetic material can be minimized without losing performance. Simulations and measurements of the printed systems show very good agreement.

PGHPF – An Optimizing High Performance Fortran Compiler for Distributed Memory Machines

Directory of Open Access Journals (Sweden)

Zeki Bozkus

1997-01-01

Full Text Available High Performance Fortran (HPF is the first widely supported, efficient, and portable parallel programming language for shared and distributed memory systems. HPF is realized through a set of directive-based extensions to Fortran 90. It enables application developers and Fortran end-users to write compact, portable, and efficient software that will compile and execute on workstations, shared memory servers, clusters, traditional supercomputers, or massively parallel processors. This article describes a production-quality HPF compiler for a set of parallel machines. Compilation techniques such as data and computation distribution, communication generation, run-time support, and optimization issues are elaborated as the basis for an HPF compiler implementation on distributed memory machines. The performance of this compiler on benchmark programs demonstrates that high efficiency can be achieved executing HPF code on parallel architectures.

Unipolar resistive switching in planar Pt/BiFeO3/Pt structure

Directory of Open Access Journals (Sweden)

Rajesh K. Katiyar

2015-03-01

Full Text Available We report unipolar resistive switching suitable for nonvolatile memory applications in polycrystalline BiFeO3 thin films in planar electrode configuration with non-overlapping Set and Reset voltages, On/Off resistance ratio of ∼104 and good data retention (verified for up to 3,000 s. We have also observed photovoltaic response in both high and low resistance states, where the photocurrent density was about three orders of magnitude higher in the low resistance state as compared to the high resistance state at an illumination power density of ∼100 mW/cm2. Resistive switching mechanisms in both resistance states of the planar device can be explained by using the conduction filament (thermo-chemical model.

Optimizing memory-bound SYMV kernel on GPU hardware accelerators

KAUST Repository

Abdelfattah, Ahmad

2013-01-01

Hardware accelerators are becoming ubiquitous high performance scientific computing. They are capable of delivering an unprecedented level of concurrent execution contexts. High-level programming language extensions (e.g., CUDA), profiling tools (e.g., PAPI-CUDA, CUDA Profiler) are paramount to improve productivity, while effectively exploiting the underlying hardware. We present an optimized numerical kernel for computing the symmetric matrix-vector product on nVidia Fermi GPUs. Due to its inherent memory-bound nature, this kernel is very critical in the tridiagonalization of a symmetric dense matrix, which is a preprocessing step to calculate the eigenpairs. Using a novel design to address the irregular memory accesses by hiding latency and increasing bandwidth, our preliminary asymptotic results show 3.5x and 2.5x fold speedups over the similar CUBLAS 4.0 kernel, and 7-8% and 30% fold improvement over the Matrix Algebra on GPU and Multicore Architectures (MAGMA) library in single and double precision arithmetics, respectively. © 2013 Springer-Verlag.

Lost-in-Space Star Identification Using Planar Triangle Principal Component Analysis Algorithm

Directory of Open Access Journals (Sweden)

Fuqiang Zhou

2015-01-01

Full Text Available It is a challenging task for a star sensor to implement star identification and determine the attitude of a spacecraft in the lost-in-space mode. Several algorithms based on triangle method are proposed for star identification in this mode. However, these methods hold great time consumption and large guide star catalog memory size. The star identification performance of these methods requires improvements. To address these problems, a star identification algorithm using planar triangle principal component analysis is presented here. A star pattern is generated based on the planar triangle created by stars within the field of view of a star sensor and the projection of the triangle. Since a projection can determine an index for a unique triangle in the catalog, the adoption of the k-vector range search technique makes this algorithm very fast. In addition, a sharing star validation method is constructed to verify the identification results. Simulation results show that the proposed algorithm is more robust than the planar triangle and P-vector algorithms under the same conditions.

A real-time multichannel memory controller and optimal mapping of memory clients to memory channels

NARCIS (Netherlands)

Gomony, M.D.; Akesson, K.B.; Goossens, K.G.W.

2015-01-01

Ever-increasing demands for main memory bandwidth and memory speed/power tradeoff led to the introduction of memories with multiple memory channels, such as Wide IO DRAM. Efficient utilization of a multichannel memory as a shared resource in multiprocessor real-time systems depends on mapping of the

Study of self-compliance behaviors and internal filament characteristics in intrinsic SiOx-based resistive switching memory

International Nuclear Information System (INIS)

Chang, Yao-Feng; Zhou, Fei; Chen, Ying-Chen; Lee, Jack C.; Fowler, Burt

2016-01-01

Self-compliance characteristics and reliability optimization are investigated in intrinsic unipolar silicon oxide (SiO x )-based resistive switching (RS) memory using TiW/SiO x /TiW device structures. The program window (difference between SET voltage and RESET voltage) is dependent on external series resistance, demonstrating that the SET process is due to a voltage-triggered mechanism. The program window has been optimized for program/erase disturbance immunity and reliability for circuit-level applications. The SET and RESET transitions have also been characterized using a dynamic conductivity method, which distinguishes the self-compliance behavior due to an internal series resistance effect (filament) in SiO x -based RS memory. By using a conceptual “filament/resistive gap (GAP)” model of the conductive filament and a proton exchange model with appropriate assumptions, the internal filament resistance and GAP resistance can be estimated for high- and low-resistance states (HRS and LRS), and are found to be independent of external series resistance. Our experimental results not only provide insights into potential reliability issues but also help to clarify the switching mechanisms and device operating characteristics of SiO x -based RS memory

External parallel sorting with multiprocessor computers

International Nuclear Information System (INIS)

Comanceau, S.I.

1984-01-01

This article describes methods of external sorting in which the entire main computer memory is used for the internal sorting of entries, forming out of them sorted segments of the greatest possible size, and outputting them to external memories. The obtained segments are merged into larger segments until all entries form one ordered segment. The described methods are suitable for sequential files stored on magnetic tape. The needs of the sorting algorithm can be met by using the relatively slow peripheral storage devices (e.g., tapes, disks, drums). The efficiency of the external sorting methods is determined by calculating the total sorting time as a function of the number of entries to be sorted and the number of parallel processors participating in the sorting process

InGaAs-based planar barrier diode as microwave rectifier

Science.gov (United States)

Farhani Zakaria, Nor; Rizal Kasjoo, Shahrir; Zailan, Zarimawaty; Mohamad Isa, Muammar; Arshad, Mohd Khairuddin Md; Taking, Sanna

2018-06-01

In this report, we proposed and simulated a new planar nonlinear rectifying device fabricated using InGaAs substrate and referred to as a planar barrier diode (PBD). Using an asymmetrical inverse-arrowhead-shaped structure between the electrodes, a nonuniform depletion region is developed, which creates a triangular energy barrier in the conducting channel. This barrier is voltage dependent and can be controlled by the applied voltage across the PBD, thus resulting in nonlinear diode-like current–voltage characteristics; thus it can be used as a rectifying device. The PBD’s working principle is explained using thermionic emission theory. Furthermore, by varying the PBD’s geometric design, the asymmetry of the current–voltage characteristics can be optimized to realize superior rectification performance. By employing the optimized structural parameters, the obtained cut-off frequency of the device was approximately 270 GHz with a curvature coefficient peak of 14 V‑1 at a low DC bias voltage of 50 mV.

System of common usage on the base of external memory devices and the SM-3 computer

International Nuclear Information System (INIS)

Baluka, G.; Vasin, A.Yu.; Ermakov, V.A.; Zhukov, G.P.; Zimin, G.N.; Namsraj, Yu.; Ostrovnoj, A.I.; Savvateev, A.S.; Salamatin, I.M.; Yanovskij, G.Ya.

1980-01-01

An easily modified system of common usage on the base of external memories and a SM-3 minicomputer replacing some pulse analysers is described. The system has merits of PA and is more advantageous with regard to effectiveness of equipment using, the possibility of changing configuration and functions, the data protection against losses due to user errors and some failures, price of one registration channel, place occupied. The system of common usage is intended for the IBR-2 pulse reactor computing centre. It is designed using the SANPO system means for SM-3 computer [ru

Memory-guided attention: Control from multiple memory systems

OpenAIRE

Hutchinson, J. Benjamin; Turk-Browne, Nicholas B.

2012-01-01

Attention is strongly influenced by both external stimuli and internal goals. However, this useful dichotomy does not readily capture the ubiquitous and often automatic contribution of past experience stored in memory. We review recent evidence about how multiple memory systems control attention, consider how such interactions are manifested in the brain, and highlight how this framework for ‘memory-guided attention’ might help systematize previous findings and guide future research.

Optimal external laryngeal manipulation versus McCoy blade in active position in patients with poor view of glottis on direct laryngoscopy

Directory of Open Access Journals (Sweden)

Arumugam Vasudevan

2010-01-01

Full Text Available Successful endotracheal intubation requires a clear view of glottis. Optimal external laryngeal manipulation may improve the view of glottis on direct laryngoscopy with Macintosh blade, but it requires another trained hand. Alternatively, McCoy laryngoscope with elevated tip may be useful. This study has been designed to compare the two techniques in patients with poor view of glottis. Two hundred patients with ′Grade 2 or more′ view of glottis on direct laryngoscopy with Macintosh blade are included in the study. Optimal external laryngeal manipulation was applied, followed by laryngoscopy with McCoy blade in activated position; and the view was noted in both situations. The two interventions were compared using Chi-square test. The overall changes, in the views, were analyzed with Wilcoxon signed rank test. Both the techniques improved the view of glottis significantly (P< 0.05. Optimal external laryngeal manipulation was significantly better than McCoy laryngoscope in active position, especially in patients with Grade 3 or 4 baseline view, poor oropharyngeal class, decreased head extension and decreased submandibular space (odds ratio = 2.36, 3.17, 3.22 and 26.48 respectively. To conclude, optimal external laryngeal manipulation is a better technique than McCoy laryngoscope in patients with poor view of glottis on direct laryngoscopy with Macintosh blade.

Variable resolution Associative Memory use and optimization for the Fast Tracker ATLAS upgrade

CERN Document Server

Annovi, A; The ATLAS collaboration; Giannetti, P; Luongo, C; Pandini, C; Volpi, G

2013-01-01

The most recent prototype of the Associative Memory (AM) chip developed for the ATLAS Fast Tracker includes ternary logic cells that can store 0, 1, or "don't care" values. This allows an enormous flexibility, with the possibility to program the precision of the spatial coincidence for each pattern and for each detector layer. We call this use of the associative memory: "variable resolution pattern recognition". A technique that can be applied to any coincidence based trigger. We describe an advanced technique to build the bank of patterns for the associative memory. Full resolution patterns are merged and split (profiting of variable resolution) to obtain the optimal set of patterns that fits in a given AM size while providing the best rejection of random coincidences without loss in efficiency.

An Optimal Biparametric Multipoint Family and Its Self-Acceleration with Memory for Solving Nonlinear Equations

Directory of Open Access Journals (Sweden)

Quan Zheng

2015-12-01

Full Text Available In this paper, a family of Steffensen-type methods of optimal order of convergence with two parameters is constructed by direct Newtonian interpolation. It satisfies the conjecture proposed by Kung and Traub (J. Assoc. Comput. Math. 1974, 21, 634–651 that an iterative method based on m evaluations per iteration without memory would arrive at the optimal convergence of order 2m-1 . Furthermore, the family of Steffensen-type methods of super convergence is suggested by using arithmetic expressions for the parameters with memory but no additional new evaluation of the function. Their error equations, asymptotic convergence constants and convergence orders are obtained. Finally, they are compared with related root-finding methods in the numerical examples.

Performance projections and design optimization of planar double gate SOI MOSFETs for logic technology applications

International Nuclear Information System (INIS)

Kranti, Abhinav; Hao Ying; Armstrong, G Alastair

2008-01-01

In this paper, by investigating the influence of source/drain extension region engineering (also known as gate–source/drain underlap) in nanoscale planar double gate (DG) SOI MOSFETs, we offer new insights into the design of future nanoscale gate-underlap DG devices to achieve ITRS projections for high performance (HP), low standby power (LSTP) and low operating power (LOP) logic technologies. The impact of high-κ gate dielectric, silicon film thickness, together with parameters associated with the lateral source/drain doping profile, is investigated in detail. The results show that spacer width along with lateral straggle can not only effectively control short-channel effects, thus presenting low off-current in a gate underlap device, but can also be optimized to achieve lower intrinsic delay and higher on–off current ratio (I on /I off ). Based on the investigation of on-current (I on ), off-current (I off ), I on /I off , intrinsic delay (τ), energy delay product and static power dissipation, we present design guidelines to select key device parameters to achieve ITRS projections. Using nominal gate lengths for different technologies, as recommended from ITRS specification, optimally designed gate-underlap DG MOSFETs with a spacer-to-straggle (s/σ) ratio of 2.3 for HP/LOP and 3.2 for LSTP logic technologies will meet ITRS projection. However, a relatively narrow range of lateral straggle lying between 7 to 8 nm is recommended. A sensitivity analysis of intrinsic delay, on-current and off-current to important parameters allows a comparative analysis of the various design options and shows that gate workfunction appears to be the most crucial parameter in the design of DG devices for all three technologies. The impact of back gate misalignment on I on , I off and τ is also investigated for optimized underlap devices

Coupling Ideality of Integrated Planar High-Q Microresonators

Science.gov (United States)

Pfeiffer, Martin H. P.; Liu, Junqiu; Geiselmann, Michael; Kippenberg, Tobias J.

2017-02-01

Chip-scale optical microresonators with integrated planar optical waveguides are useful building blocks for linear, nonlinear, and quantum-optical photonic devices alike. Loss reduction through improving fabrication processes results in several integrated microresonator platforms attaining quality (Q ) factors of several millions. Beyond the improvement of the quality factor, the ability to operate the microresonator with high coupling ideality in the overcoupled regime is of central importance. In this regime, the dominant source of loss constitutes the coupling to a single desired output channel, which is particularly important not only for quantum-optical applications such as the generation of squeezed light and correlated photon pairs but also for linear and nonlinear photonics. However, to date, the coupling ideality in integrated photonic microresonators is not well understood, in particular, design-dependent losses and their impact on the regime of high ideality. Here we investigate design-dependent parasitic losses described by the coupling ideality of the commonly employed microresonator design consisting of a microring-resonator waveguide side coupled to a straight bus waveguide, a system which is not properly described by the conventional input-output theory of open systems due to the presence of higher-order modes. By systematic characterization of multimode high-Q silicon nitride microresonator devices, we show that this design can suffer from low coupling ideality. By performing 3D simulations, we identify the coupling to higher-order bus waveguide modes as the dominant origin of parasitic losses which lead to the low coupling ideality. Using suitably designed bus waveguides, parasitic losses are mitigated with a nearly unity ideality and strong overcoupling (i.e., a ratio of external coupling to internal resonator loss rate >9 ) are demonstrated. Moreover, we find that different resonator modes can exchange power through the coupler, which, therefore

Measurements of a vortex transitional ndro Josephson memory cell

International Nuclear Information System (INIS)

Tahara, S.; Ishida, I.; Hidaka, M.; Nagasawa, S.; Ajisawa, Y.; Wada, Y.

1988-01-01

A novel vortex transitional NDRO Jospehson memory cell has been successfully fabricated and tested. The memory cell consists of two superconducting loops and a two-junction interferometer gate as a sense gate. The superconducting loop contains one Josephson junction and inductances, and stores single flux quantum. The memory cell employs vortex transitions in the superconducting loops for writing and reading data. The memory cell chips have been fabricated using niobium planarization process. The +-21 percent address signal current margin and the +-33 percent sense gate current margin have been obtained experimentally. The memory operation of the cell driven by the two-junction interferometer gates has been accurately demonstrated

Externalities, Border Trade and Illegal Production: An Optimal Tax Approach to Alcohol Policy

OpenAIRE

Aronsson, Thomas; Sjögren, Tomas

2005-01-01

This paper deals with optimal income and commodity taxation in an economy, where alcohol is an externality-generating consumption good. In our model, alcohol can be bought domestically, imported (via border trade) or produced illegally. Border trade implies an incentive to set the domestic alcohol tax below the marginal social damage of alcohol, and to tax (subsidize) commodities which are complementary with (substitutable for) alcohol. In addition, since leisure and alcohol consumption are g...

The Planar Sandwich and Other 1D Planar Heat Flow Test Problems in ExactPack

Energy Technology Data Exchange (ETDEWEB)

Singleton, Jr., Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-01-24

This report documents the implementation of several related 1D heat flow problems in the verification package ExactPack [1]. In particular, the planar sandwich class defined in Ref. [2], as well as the classes PlanarSandwichHot, PlanarSandwichHalf, and other generalizations of the planar sandwich problem, are defined and documented here. A rather general treatment of 1D heat flow is presented, whose main results have been implemented in the class Rod1D. All planar sandwich classes are derived from the parent class Rod1D.

Short-term memories with a stochastic perturbation

International Nuclear Information System (INIS)

Pontes, Jose C.A. de; Batista, Antonio M.; Viana, Ricardo L.; Lopes, Sergio R.

2005-01-01

We investigate short-term memories in linear and weakly nonlinear coupled map lattices with a periodic external input. We use locally coupled maps to present numerical results about short-term memory formation adding a stochastic perturbation in the maps and in the external input

Proposal of limit moment equation applicable to planar/non-planar flaw in wall thinned pipes under bending

International Nuclear Information System (INIS)

Tsuji, Masataka; Meshii, Toshiyuki

2011-01-01

Highlights: → A limit moment equation applicable to planar/non-planar flaw of 0 ≤ θ ≤ π found in wall thinned straight pipes was proposed. → An idea to rationally classify planar/non-planar flaw in wall thinned pipes was proposed. → The equation based on the experimental observation focused on the fracture mode. - Abstract: In this paper, a limit bending moment equation applicable to all types of planar and non-planar flaws in wall-thinned straight pipes under bending was proposed. A system to rationally classify the planar/non-planar flaws in wall-thinned pipes was suggested based on experimental observations focused on the fracture mode. The results demonstrate the importance of distinguishing between axial and circumferential long flaws in wall-thinned pipes.

Simultaneous Calibration: A Joint Optimization Approach for Multiple Kinect and External Cameras

Directory of Open Access Journals (Sweden)

Yajie Liao

2017-06-01

Full Text Available Camera calibration is a crucial problem in many applications, such as 3D reconstruction, structure from motion, object tracking and face alignment. Numerous methods have been proposed to solve the above problem with good performance in the last few decades. However, few methods are targeted at joint calibration of multi-sensors (more than four devices, which normally is a practical issue in the real-time systems. In this paper, we propose a novel method and a corresponding workflow framework to simultaneously calibrate relative poses of a Kinect and three external cameras. By optimizing the final cost function and adding corresponding weights to the external cameras in different locations, an effective joint calibration of multiple devices is constructed. Furthermore, the method is tested in a practical platform, and experiment results show that the proposed joint calibration method can achieve a satisfactory performance in a project real-time system and its accuracy is higher than the manufacturer’s calibration.

Simultaneous Calibration: A Joint Optimization Approach for Multiple Kinect and External Cameras.

Science.gov (United States)

Liao, Yajie; Sun, Ying; Li, Gongfa; Kong, Jianyi; Jiang, Guozhang; Jiang, Du; Cai, Haibin; Ju, Zhaojie; Yu, Hui; Liu, Honghai

2017-06-24

Camera calibration is a crucial problem in many applications, such as 3D reconstruction, structure from motion, object tracking and face alignment. Numerous methods have been proposed to solve the above problem with good performance in the last few decades. However, few methods are targeted at joint calibration of multi-sensors (more than four devices), which normally is a practical issue in the real-time systems. In this paper, we propose a novel method and a corresponding workflow framework to simultaneously calibrate relative poses of a Kinect and three external cameras. By optimizing the final cost function and adding corresponding weights to the external cameras in different locations, an effective joint calibration of multiple devices is constructed. Furthermore, the method is tested in a practical platform, and experiment results show that the proposed joint calibration method can achieve a satisfactory performance in a project real-time system and its accuracy is higher than the manufacturer's calibration.

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.

Multiobjective optimization with a modified simulated annealing algorithm for external beam radiotherapy treatment planning

International Nuclear Information System (INIS)

Aubry, Jean-Francois; Beaulieu, Frederic; Sevigny, Caroline; Beaulieu, Luc; Tremblay, Daniel

2006-01-01

Inverse planning in external beam radiotherapy often requires a scalar objective function that incorporates importance factors to mimic the planner's preferences between conflicting objectives. Defining those importance factors is not straightforward, and frequently leads to an iterative process in which the importance factors become variables of the optimization problem. In order to avoid this drawback of inverse planning, optimization using algorithms more suited to multiobjective optimization, such as evolutionary algorithms, has been suggested. However, much inverse planning software, including one based on simulated annealing developed at our institution, does not include multiobjective-oriented algorithms. This work investigates the performance of a modified simulated annealing algorithm used to drive aperture-based intensity-modulated radiotherapy inverse planning software in a multiobjective optimization framework. For a few test cases involving gastric cancer patients, the use of this new algorithm leads to an increase in optimization speed of a little more than a factor of 2 over a conventional simulated annealing algorithm, while giving a close approximation of the solutions produced by a standard simulated annealing. A simple graphical user interface designed to facilitate the decision-making process that follows an optimization is also presented

Externally induced frontoparietal synchronization modulates network dynamics and enhances working memory performance.

Science.gov (United States)

Violante, Ines R; Li, Lucia M; Carmichael, David W; Lorenz, Romy; Leech, Robert; Hampshire, Adam; Rothwell, John C; Sharp, David J

2017-03-14

Cognitive functions such as working memory (WM) are emergent properties of large-scale network interactions. Synchronisation of oscillatory activity might contribute to WM by enabling the coordination of long-range processes. However, causal evidence for the way oscillatory activity shapes network dynamics and behavior in humans is limited. Here we applied transcranial alternating current stimulation (tACS) to exogenously modulate oscillatory activity in a right frontoparietal network that supports WM. Externally induced synchronization improved performance when cognitive demands were high. Simultaneously collected fMRI data reveals tACS effects dependent on the relative phase of the stimulation and the internal cognitive processing state. Specifically, synchronous tACS during the verbal WM task increased parietal activity, which correlated with behavioral performance. Furthermore, functional connectivity results indicate that the relative phase of frontoparietal stimulation influences information flow within the WM network. Overall, our findings demonstrate a link between behavioral performance in a demanding WM task and large-scale brain synchronization.

Rank one chaos in a class of planar systems with heteroclinic cycle.

Science.gov (United States)

Chen, Fengjuan; Han, Maoan

2009-12-01

In this paper, we study rank one chaos in a class of planar systems with heteroclinic cycle. We first find a stable limit cycle inside the heteroclinic cycle. We then add an external periodic forcing to create rank one chaos. We follow a step-by-step procedure guided by the theory of rank one chaos to find experimental evidence of strange attractors with Sinai, Ruelle, and Bowen measures.

Resource-sharing between internal maintenance and external selection modulates attentional capture by working memory content

Directory of Open Access Journals (Sweden)

Anastasia eKiyonaga

2014-08-01

Full Text Available It is unclear why and under what circumstances working memory (WM and attention interact. Here, we apply the logic of the time-based resource-sharing (TBRS model of WM (e.g., Barrouillet, Bernardin, & Camos, 2004 to explore the mixed findings of a separate, but related, literature that studies the guidance of visual attention by WM contents. Specifically, we hypothesize that the linkage between WM representations and visual attention is governed by a time-shared cognitive resource that alternately refreshes internal (WM and selects external (visual attention information. If this were the case, WM content should guide visual attention (involuntarily, but only when there is time for it to be refreshed in an internal focus of attention. To provide an initial test for this hypothesis, we examined whether the amount of unoccupied time during a WM delay could impact the magnitude of attentional capture by WM contents. Participants were presented with a series of visual search trials while they maintained a WM cue for a delayed-recognition test. WM cues could coincide with the search target, a distracter, or neither. We varied both the number of searches to be performed, and the amount of available time to perform them. Slowing of visual search by a WM matching distracter—and facilitation by a matching target—were curtailed when the delay was filled with fast-paced (refreshing-preventing search trials, as was subsequent memory probe accuracy. WM content may, therefore, only capture visual attention when it can be refreshed, suggesting that internal (WM and external attention demands reciprocally impact one another because they share a limited resource. The TBRS rationale can thus be applied in a novel context to explain why WM contents capture attention, and under what conditions that effect should be observed.

Exploring Shared-Memory Optimizations for an Unstructured Mesh CFD Application on Modern Parallel Systems

KAUST Repository

Mudigere, Dheevatsa

2015-05-01

In this work, we revisit the 1999 Gordon Bell Prize winning PETSc-FUN3D aerodynamics code, extending it with highly-tuned shared-memory parallelization and detailed performance analysis on modern highly parallel architectures. An unstructured-grid implicit flow solver, which forms the backbone of computational aerodynamics, poses particular challenges due to its large irregular working sets, unstructured memory accesses, and variable/limited amount of parallelism. This code, based on a domain decomposition approach, exposes tradeoffs between the number of threads assigned to each MPI-rank sub domain, and the total number of domains. By applying several algorithm- and architecture-aware optimization techniques for unstructured grids, we show a 6.9X speed-up in performance on a single-node Intel® XeonTM1 E5 2690 v2 processor relative to the out-of-the-box compilation. Our scaling studies on TACC Stampede supercomputer show that our optimizations continue to provide performance benefits over baseline implementation as we scale up to 256 nodes.

Variability in DMSA reporting following urinary tract infection in children: pinhole, planar, and pinhole with planar

International Nuclear Information System (INIS)

Rossleigh, M.A.; Christian, C.L.; Craig, J.C.; Howman-Giles, R.B.; Grunewald, S.

2004-01-01

Purpose: To determine whether the provision of DMSA images obtained by pinhole collimation reduces inter-observer variability of reporting compared with planar DMSA images alone. Methods: One hundred consecutive DMSA images were independently interpreted three times (pinhole alone, planar alone, pinhole and planar) by four participating nuclear medicine specialists from different departments and in random order. The presence or absence of renal parenchymal abnormality was classified using the modified four level grading system of Goldraich with mean values for the 6 comparisons reported. Results: The proportion of DMSA images interpreted as abnormal was 31% for planar, 34% for pinhole and 33% for planar with pinhole. Agreement was 89% for planar alone, 89% for pinhole alone and 90% for planar with pinhole, with kappa values 0.74, 0.75 and 0.80 respectively for the normal-abnormal scan classification of individual children. These results did not vary appreciably whether interpretation of patients, kidneys or kidney zones was compared. Reasons for disagreement in reporting included different interpretations of 'abnormalities' as normal anatomical variations (splenic impression, fetal lobulation, duplex collecting systems, column of Bertin) or true parenchymal abnormalities, different adjustments in thresholds for reporting abnormality when images were technically suboptimal, different weighting given to pinhole and planar images when both were provided, and error. Conclusion: Four experienced nuclear medicine physicians showed substantial agreement in the interpretation of planar alone, pinhole alone and planar with pinhole DMSA images, but the provision of both sets of images, planar and pinhole, did not reduce variability. (authors)

Analysis and Optimization of a Novel 2-D Magnet Array with Gaps and Staggers for a Moving-Magnet Planar Motor

Science.gov (United States)

Chen, Xuedong; Zeng, Lizhan

2018-01-01

This paper presents a novel 2-D magnet array with gaps and staggers, which is especially suitable for magnetically levitated planar motor with moving magnets. The magnetic flux density distribution is derived by Fourier analysis and superposition. The influences of gaps and staggers on high-order harmonics and flux density were analyzed, and the optimized design is presented. Compared with the other improved structures based on traditional Halbach magnet arrays, the proposed design has the lowest high-order harmonics percentage, and the characteristics of flux density meet the demand of high acceleration in horizontal directions. It is also lightweight and easy to manufacture. The proposed magnet array was built, and the calculation results have been verified with experiment. PMID:29300323

Planar structured perovskite solar cells by hybrid physical chemical vapor deposition with optimized perovskite film thickness

Science.gov (United States)

Wei, Xiangyang; Peng, Yanke; Jing, Gaoshan; Cui, Tianhong

2018-05-01

The thickness of perovskite absorber layer is a critical parameter to determine a planar structured perovskite solar cell’s performance. By modifying the spin coating speed and PbI2/N,N-dimethylformamide (DMF) solution concentration, the thickness of perovskite absorber layer was optimized to obtain high-performance solar cells. Using a PbI2/DMF solution of 1.3 mol/L, maximum power conversion efficiency (PCE) of a perovskite solar cell is 15.5% with a perovskite film of 413 nm at 5000 rpm, and PCE of 14.3% was also obtained for a solar cell with a perovskite film of 182 nm thick. It is derived that higher concentration of PbI2/DMF will result in better perovskite solar cells. Additionally, these perovskite solar cells are highly uniform. In 14 sets of solar cells, standard deviations of 11 sets of solar cells were less than 0.50% and the smallest standard deviation was 0.25%, which demonstrates the reliability and effectiveness of hybrid physical chemical vapor deposition (HPCVD) method.

Optimized electricity expansions with external costs internalized and risk of severe accidents as a new criterion in the decision analysis

Energy Technology Data Exchange (ETDEWEB)

Martin del Campo M, C.; Estrada S, G. J., E-mail: cmcm@fi-b.unam.mx [UNAM, Facultad de Ingenieria, Departamento de Sistemas Energeticos, Paseo Cuauhnahuac 8532, 62550 Jiutepec, Morelos (Mexico)

2011-11-15

The external cost of severe accidents was incorporated as a new element for the assessment of energy technologies in the expansion plans of the Mexican electric generating system. Optimizations of the electric expansions were made by internalizing the external cost into the objective function of the WASP-IV model as a variable cost, and these expansions were compared with the expansion plans that did not internalize them. Average external costs reported by the Extern E Project were used for each type of technology and were added to the variable component of operation and maintenance cost in the study cases in which the externalises were internalized. Special attention was paid to study the convenience of including nuclear energy in the generating mix. The comparative assessment of six expansion plans was made by means of the Position Vector of Minimum Regret Analysis (PVMRA) decision analysis tool. The expansion plans were ranked according to seven decision criteria which consider internal costs, economical impact associated with incremental fuel prices, diversity, external costs, foreign capital fraction, carbon-free fraction, and external costs of severe accidents. A set of data for the calculation of the last criterion was obtained from a Report of the European Commission. We found that with the external costs included in the optimization process of WASP-IV, better electric expansion plans, with lower total (internal + external) generating costs, were found. On the other hand, the plans which included the participation of nuclear power plants were in general relatively more attractive than the plans that did not. (Author)

Desain dan Optimasi Antena Pita Lebar Planar Monopole Bentuk Sembarang dengan Algoritma Genetika dan Metode Momen

Directory of Open Access Journals (Sweden)

Joko Suryana

2018-04-01

Full Text Available This paper presents a new approach in designing an ultra wideband minimum dispersion antenna optimally to avoid the degradation of broadband communications system performance. Design and iterative optimization are applied to an arbitrary shape of planar monopole antenna using a genetic algorithm combined with the moment method, abbreviated as AGMM method, and implemented with Matlab. Two arbitrary shapes of planar monopole antennas have been implemented in compact physical size using AGMM optimization, each having 9.1 GHz and 7.4 GHz bandwidths, the lowest frequency of 1.9 GHz and 2.7 GHz and fidelity 0.6 and 0.64 for any arbitrary discrete antenna and edge profile antenna. This method can be applied to design any arbitrary shapes of an ultra-wideband antenna with each has wide bandwidth more than 7 GHz, the lowest frequency below 3 GHz and a minimum fidelity of 0,55 that is suitable for high- speed communication, such as 5G system. Makalah ini memaparkan pendekatan baru dalam perancangan optimal antena pita lebar dispersi minimum untuk menghindari penurunan kinerja sistem komunikasi kecepatan tinggi. Desain dan optimasi iteratif diterapkan pada antena planar monopole bentuk sembarang menggunakan algoritma genetika yang digabungkan dengan metode momen yang disingkat sebagai metode AGMM. Metode ini diimplementasikan dengan Matlab. Dua buah tipe antena planar monopole pita lebar bentuk sembarang dan ukuran fisik kompak berhasil dirancang dengan AGMM yang masing-masing memiliki lebar pita 9,1 GHz dan 7,4 GHz, frekuensi terendah 1,9 GHz dan 2,7 GHz serta memiliki fidelity 0,6 dan 0,64 untuk antena diskrit sembarang dan antena profil tepi sembarang. Metode ini dapat diterapkan untuk merancang antena pita lebar bentuk sembarang dengan lebar pita lebih dari 7 GHz, frekuensi terendah < 3 GHz dan memiliki fidelity di atas 0,55 yang cocok untuk komunikasi berkecepatan tinggi, misalnya sistem 5G.

Optimization of perceptual learning: effects of task difficulty and external noise in older adults.

Science.gov (United States)

DeLoss, Denton J; Watanabe, Takeo; Andersen, George J

2014-06-01

Previous research has shown a wide array of age-related declines in vision. The current study examined the effects of perceptual learning (PL), external noise, and task difficulty in fine orientation discrimination with older individuals (mean age 71.73, range 65-91). Thirty-two older subjects participated in seven 1.5-h sessions conducted on separate days over a three-week period. A two-alternative forced choice procedure was used in discriminating the orientation of Gabor patches. Four training groups were examined in which the standard orientations for training were either easy or difficult and included either external noise (additive Gaussian noise) or no external noise. In addition, the transfer to an untrained orientation and noise levels were examined. An analysis of the four groups prior to training indicated no significant differences between the groups. An analysis of the change in performance post-training indicated that the degree of learning was related to task difficulty and the presence of external noise during training. In addition, measurements of pupil diameter indicated that changes in orientation discrimination were not associated with changes in retinal illuminance. These results suggest that task difficulty and training in noise are factors important for optimizing the effects of training among older individuals. Copyright © 2013 Elsevier B.V. All rights reserved.

Intelligent design optimization of a shape-memory-alloy-actuated reconfigurable wing

Science.gov (United States)

Lagoudas, Dimitris C.; Strelec, Justin K.; Yen, John; Khan, Mohammad A.

2000-06-01

The unique thermal and mechanical properties offered by shape memory alloys (SMAs) present exciting possibilities in the field of aerospace engineering. When properly trained, SMA wires act as linear actuators by contracting when heated and returning to their original shape when cooled. It has been shown experimentally that the overall shape of an airfoil can be altered by activating several attached SMA wire actuators. This shape-change can effectively increase the efficiency of a wing in flight at several different flow regimes. To determine the necessary placement of these wire actuators within the wing, an optimization method that incorporates a fully-coupled structural, thermal, and aerodynamic analysis has been utilized. Due to the complexity of the fully-coupled analysis, intelligent optimization methods such as genetic algorithms have been used to efficiently converge to an optimal solution. The genetic algorithm used in this case is a hybrid version with global search and optimization capabilities augmented by the simplex method as a local search technique. For the reconfigurable wing, each chromosome represents a realizable airfoil configuration and its genes are the SMA actuators, described by their location and maximum transformation strain. The genetic algorithm has been used to optimize this design problem to maximize the lift-to-drag ratio for a reconfigured airfoil shape.

The ATLAS Planar Pixel Sensor R and D project

International Nuclear Information System (INIS)

Beimforde, M.

2011-01-01

Within the R and D project on Planar Pixel Sensor Technology for the ATLAS inner detector upgrade, the use of planar pixel sensors for highest fluences as well as large area silicon detectors is investigated. The main research goals are optimizing the signal size after irradiations, reducing the inactive sensor edges, adjusting the readout electronics to the radiation induced decrease of the signal sizes, and reducing the production costs. Planar n-in-p sensors have been irradiated with neutrons and protons up to fluences of 2x10 16 n eq /cm 2 and 1x10 16 n eq /cm 2 , respectively, to study the collected charge as a function of the irradiation dose received. Furthermore comparisons of irradiated standard 300μm and thin 140μm sensors will be presented showing an increase of signal sizes after irradiation in thin sensors. Tuning studies of the present ATLAS front end electronics show possibilities to decrease the discriminator threshold of the present FE-I3 read out chips to less than 1500 electrons. In the present pixel detector upgrade scenarios a flat stave design for the innermost layers requires reduced inactive areas at the sensor edges to ensure low geometric inefficiencies. Investigations towards achieving slim edges presented here show possibilities to reduce the width of the inactive area to less than 500μm. Furthermore, a brief overview of present simulation activities within the Planar Pixel R and D project is given.

Optimization of colour quality of LED lighting with reference to memory colours

OpenAIRE

Smet, Kevin; Ryckaert, Wouter; Pointer, Michael R.; Deconinck, Geert; Hanselaer, Peter

2012-01-01

Simulated and real tri- and tetrachromatic light-emitting-diode (LED) clusters were optimized for luminous efficacy of radiation (LER) and the memory colour quality metric developed by the authors. The simulated clusters showed no significant differences in achievable colour quality and LER between the different cluster types investigated. The real clusters (composed of commercially available LEDs) showed substantial differences in achievable colour quality and LER between the different clus...

How to draw a planarization

NARCIS (Netherlands)

Bläsius, T.; Radermacher, M.; Rutter, I.; Steffen, B.; Baier, C.; van den Brand, M.; Eder, J.; Hinchey, M.; Margaria, T.

2017-01-01

We study the problem of computing straight-line drawings of non-planar graphs with few crossings. We assume that a crossing-minimization algorithm is applied first, yielding a planarization, i.e., a planar graph with a dummy vertex for each crossing, that fixes the topology of the resulting drawing.

Estimation of Setup Uncertainty Using Planar and MVCT Imaging for Gynecologic Malignancies

International Nuclear Information System (INIS)

Santanam, Lakshmi; Esthappan, Jacqueline; Mutic, Sasa; Klein, Eric E.; Goddu, S. Murty; Chaudhari, Summer; Wahab, Sasha; El Naqa, Issam M.; Low, Daniel A.; Grigsby, Perry W.

2008-01-01

Purpose: This prospective study investigates gynecologic malignancy online treatment setup error corrections using planar kilovoltage/megavoltage (KV/MV) imaging and helical MV computed tomography (MVCT) imaging. Methods and Materials: Twenty patients were divided into two groups. The first group (10 patients) was imaged and treated using a conventional linear accelerator (LINAC) with image-guidance capabilities, whereas the second group (10 patients) was treated using tomotherapy with MVCT capabilities. Patients treated on the LINAC underwent planar KV and portal MV imaging and a two-dimensional image registration algorithm was used to match these images to digitally reconstructed radiographs (DRRs). Patients that were treated using tomotherapy underwent MVCT imaging, and a three-dimensional image registration algorithm was used to match planning CT to MVCT images. Subsequent repositioning shifts were applied before each treatment and recorded for further analysis. To assess intrafraction motion, 5 of the 10 patients treated on the LINAC underwent posttreatment planar imaging and DRR matching. Based on these data, patient position uncertainties along with estimated margins based on well-known recipes were determined. Results: The errors associated with patient positioning ranged from 0.13 cm to 0.38 cm, for patients imaged on LINAC and 0.13 cm to 0.48 cm for patients imaged on tomotherapy. Our institutional clinical target volume-PTV margin value of 0.7 cm lies inside the confidence interval of the margins established using both planar and MVCT imaging. Conclusion: Use of high-quality daily planar imaging, volumetric MVCT imaging, and setup corrections yields excellent setup accuracy and can help reduce margins for the external beam treatment of gynecologic malignancies

Spike-based population coding and working memory.

Directory of Open Access Journals (Sweden)

Martin Boerlin

2011-02-01

Full Text Available Compelling behavioral evidence suggests that humans can make optimal decisions despite the uncertainty inherent in perceptual or motor tasks. A key question in neuroscience is how populations of spiking neurons can implement such probabilistic computations. In this article, we develop a comprehensive framework for optimal, spike-based sensory integration and working memory in a dynamic environment. We propose that probability distributions are inferred spike-per-spike in recurrently connected networks of integrate-and-fire neurons. As a result, these networks can combine sensory cues optimally, track the state of a time-varying stimulus and memorize accumulated evidence over periods much longer than the time constant of single neurons. Importantly, we propose that population responses and persistent working memory states represent entire probability distributions and not only single stimulus values. These memories are reflected by sustained, asynchronous patterns of activity which make relevant information available to downstream neurons within their short time window of integration. Model neurons act as predictive encoders, only firing spikes which account for new information that has not yet been signaled. Thus, spike times signal deterministically a prediction error, contrary to rate codes in which spike times are considered to be random samples of an underlying firing rate. As a consequence of this coding scheme, a multitude of spike patterns can reliably encode the same information. This results in weakly correlated, Poisson-like spike trains that are sensitive to initial conditions but robust to even high levels of external neural noise. This spike train variability reproduces the one observed in cortical sensory spike trains, but cannot be equated to noise. On the contrary, it is a consequence of optimal spike-based inference. In contrast, we show that rate-based models perform poorly when implemented with stochastically spiking neurons.

Design of special planar linkages

CERN Document Server

Zhao, Jing-Shan; Ma, Ning; Chu, Fulei

2013-01-01

Planar linkages play a very important role in mechanical engineering. As the simplest closed chain mechanisms, planar four-bar linkages are widely used in mechanical engineering, civil engineering and aerospace engineering.Design of Special Planar Linkages proposes a uniform design theory for planar four-bar linkages. The merit of the method proposed in this book is that it allows engineers to directly obtain accurate results when there are such solutions for the specified n precise positions; otherwise, the best approximate solutions will be found. This book discusses the kinematics and reach

Enhancement of white light OLED efficiency by combining both internal and external light extraction structures

Science.gov (United States)

Kao, I.-Ling; Ku, Chun-Neng; Chen, Yi-Ping; Lin, Ding-Zheng

2012-09-01

We proposed an internal nanostructure with a high reflective index planarization layer to solve the optical loss due to the reflective index mismatch between ITO and glass substrate. In our experiments, we found the electrical property of OLED device was significantly influenced by the internal nanostructures without planarization layer. Moreover, the internal extraction structure (IES) is not necessarily beneficial for light extraction. Therefore, we proposed a new substrate combine both internal and external extraction structure (EES) to extract trapping light. We successfully developed a high refractive index (N 1.7) planarization material with flat surface (RMS roughness < 2 nm), and improved about 70% device efficiency compared to traditional glass substrate.

A planar lens based on the electrowetting of two immiscible liquids

International Nuclear Information System (INIS)

Liu Chaoxuan; Park, Jihwan; Choi, Jin-Woo

2008-01-01

This paper reports the development and characterization of a planar liquid lens based on electrowetting. The working concept of electrowetting two immiscible liquids is demonstrated with measurement and characterization of contact angles with regard to externally applied electric voltages. Consequently, a planar liquid lens is designed and implemented based on this competitive electrowetting. A droplet of silicone oil confined in an aqueous solution (1% KCl) works as a liquid lens. Electrowetting then controls the shape of the confined silicone oil and the focal length of the liquid lens varies depending upon an applied dc voltage. A unique feature of this lens design is the double-ring planar electrodes beneath the hydrophobic substrate. While an outer ring electrode provides an initial boundary for the silicone oil droplet, an inner ring works as the actuation electrode for the lens. Further, the planar electrodes, instead of vertical or out-of-plane wall electrodes, facilitate the integration of liquid lenses into microfluidic systems. With the voltage applied in the range of 50–250 V, the confined silicone oil droplet changed its shape and the optical magnification of a 3 mm-diameter liquid lens was clearly demonstrated. Moreover, focal lengths of liquid lenses with diameters of 2 mm, 3 mm and 4 mm were characterized, respectively. The obtained results suggest that a larger lens diameter yields a longer focal length and a wider range of focal length change in response to voltage. The demonstrated liquid lens has a simple structure and is easy to fabricate

Optimization of memory use of fragment extension-based protein-ligand docking with an original fast minimum cost flow algorithm.

Science.gov (United States)

Yanagisawa, Keisuke; Komine, Shunta; Kubota, Rikuto; Ohue, Masahito; Akiyama, Yutaka

2018-03-16

The need to accelerate large-scale protein-ligand docking in virtual screening against a huge compound database led researchers to propose a strategy that entails memorizing the evaluation result of the partial structure of a compound and reusing it to evaluate other compounds. However, the previous method required frequent disk accesses, resulting in insufficient acceleration. Thus, more efficient memory usage can be expected to lead to further acceleration, and optimal memory usage could be achieved by solving the minimum cost flow problem. In this research, we propose a fast algorithm for the minimum cost flow problem utilizing the characteristics of the graph generated for this problem as constraints. The proposed algorithm, which optimized memory usage, was approximately seven times faster compared to existing minimum cost flow algorithms. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

Optimizing Memory Usage in L4-Based Microkernel

OpenAIRE

Petre Eftime; Lucian Mogoşanu; Mihai Carabaş; Răzvan Deaconescu; Laura Gheorghe; Valentin Gabriel Voiculescu

2017-01-01

Memory allocation is a critical aspect of any modern operating system kernel because it must run continuously for long periods of time, therefore memory leaks and inefficiency must be eliminated. This paper presents different memory management algorithms and their aplicability to an L4-based microkernel. We aim to reduce memory usage and increase the performance of allocation and deallocation of memory.

Two-loop planar master integrals for the production of off-shell vector bosons in hadron collisions

International Nuclear Information System (INIS)

Henn, Johannes M.; Melnikov, Kirill; Smirnov, Vladimir A.

2014-01-01

We describe the calculation of all planar master integrals that are needed for the computation of NNLO QCD corrections to the production of two off-shell vector bosons in hadron collisions. The most complicated representatives of integrals in this class are the two-loop four-point functions where two external lines are on the light-cone and two other external lines have different invariant masses. We compute these and other relevant integrals analytically using differential equations in external kinematic variables and express our results in terms of Goncharov polylogarithms. The case of two equal off-shellnesses, recently considered in ref. http://dx.doi.org/10.1007/JHEP08(2013)070, appears as a particular case of our general solution

Study of Internal and External Leaks in Tests of Anode-Supported SOFCs

DEFF Research Database (Denmark)

Rasmussen, Jens Foldager Bregnballe; Hendriksen, Peter Vang; Hagen, Anke

2008-01-01

A planar anode-supported solid oxide fuel cell (SOFC) has been tested to investigate gas tightness of the electrolyte and the applied seals. Gas leaks reduce the efficiency of the SOFC and it is thus important to determine and minimise them. Probe gases (He and Ar) and a Quadrupole Mass Spectrome......A planar anode-supported solid oxide fuel cell (SOFC) has been tested to investigate gas tightness of the electrolyte and the applied seals. Gas leaks reduce the efficiency of the SOFC and it is thus important to determine and minimise them. Probe gases (He and Ar) and a Quadrupole Mass...... Spectrometer were used to detect both internal (through electrolyte) and external (through seals) gas leaks. The internal gas leak through the electrolyte was quantified under different conditions, as was the external leak from the surroundings to the anode. The internal gas leak did not depend on the pressure...... difference between the anode and the cathode gas compartment, and can thus be described as diffusion driven. External leaks between the surroundings and the anode, but not the cathode gas compartment was observed. They were influenced by the pressure difference and are thus driven by both concentration...

Working Memory as Internal Attention: Toward an Integrative Account of Internal and External Selection Processes

Science.gov (United States)

Kiyonaga, Anastasia; Egner, Tobias

2012-01-01

Working memory (WM) and attention have been studied as separate cognitive constructs, although it has long been acknowledged that attention plays an important role in controlling the activation, maintenance, and manipulation of representations in WM. WM has, conversely, been thought of as a means of maintaining representations to voluntarily guide perceptual selective attention. It has more recently been observed, however, that the contents of WM can capture visual attention, even when such internally maintained representations are irrelevant, and often disruptive, to the immediate external task. Thus the precise relationship between WM and attention remains unclear, but it appears that they may bi-directionally impact one another, whether or not internal representations are consistent with external perceptual goals. This reciprocal relationship seems, further, to be constrained by limited cognitive resources to handle demands in either maintenance or selection. We propose here that the close relationship between WM and attention may be best described as a give-and-take interdependence between attention directed toward actively maintained internal representations (traditionally considered WM) versus external perceptual stimuli (traditionally considered selective attention), underpinned by their shared reliance on a common cognitive resource. Put simply, we argue that WM and attention should no longer be considered as separate systems or concepts, but as competing and impacting one another because they rely on the same limited resource. This framework can offer an explanation for the capture of visual attention by irrelevant WM contents, as well as a straightforward account of the underspecified relationship between WM and attention. PMID:23233157

Working memory as internal attention: toward an integrative account of internal and external selection processes.

Science.gov (United States)

Kiyonaga, Anastasia; Egner, Tobias

2013-04-01

Working memory (WM) and attention have been studied as separate cognitive constructs, although it has long been acknowledged that attention plays an important role in controlling the activation, maintenance, and manipulation of representations in WM. WM has, conversely, been thought of as a means of maintaining representations to voluntarily guide perceptual selective attention. It has more recently been observed, however, that the contents of WM can capture visual attention, even when such internally maintained representations are irrelevant, and often disruptive, to the immediate external task. Thus, the precise relationship between WM and attention remains unclear, but it appears that they may bidirectionally impact one another, whether or not internal representations are consistent with the external perceptual goals. This reciprocal relationship seems, further, to be constrained by limited cognitive resources to handle demands in either maintenance or selection. We propose here that the close relationship between WM and attention may be best described as a give-and-take interdependence between attention directed toward either actively maintained internal representations (traditionally considered WM) or external perceptual stimuli (traditionally considered selective attention), underpinned by their shared reliance on a common cognitive resource. Put simply, we argue that WM and attention should no longer be considered as separate systems or concepts, but as competing and influencing one another because they rely on the same limited resource. This framework can offer an explanation for the capture of visual attention by irrelevant WM contents, as well as a straightforward account of the underspecified relationship between WM and attention.

Need for Cognition and False Memory: Can One's Natural Processing Style Be Manipulated by External Factors?

Science.gov (United States)

Wootan, Samantha S; Leding, Juliana K

2015-01-01

The purpose of this experiment was to provide an enhanced understanding of need for cognition (NFC) and its influence on one's memory accuracy. People who are high in NFC tend to put more cognitive effort into their mental processes than their low-NFC counterparts. To determine whether one's natural processing tendencies, as determined by NFC, can be influenced by external factors, manipulations to levels of processing were added. Participants viewed word lists from the Deese-Roediger-McDermott (DRM) paradigm and were instructed to process half of the DRM lists deeply and the other half shallowly. After all the lists were presented, participants completed 3 successive recall tests. The deep processing condition produced higher rates of false memories for both NFC groups than the shallow processing condition. In addition, the high-NFC group produced higher rates of target recall in both the deep and shallow conditions than the low-NFC group. However, the high-NFC group also produced higher rates of false recall for the shallowly processed lists. These data indicate that high-NFC people exhibit enhanced target recall for word lists, which may come at the expense of overall accuracy due to the increase of false recall.

Bi-periodicity evoked by periodic external inputs in delayed Cohen-Grossberg-type bidirectional associative memory networks

Science.gov (United States)

Cao, Jinde; Wang, Yanyan

2010-05-01

In this paper, the bi-periodicity issue is discussed for Cohen-Grossberg-type (CG-type) bidirectional associative memory (BAM) neural networks (NNs) with time-varying delays and standard activation functions. It is shown that the model considered in this paper has two periodic orbits located in saturation regions and they are locally exponentially stable. Meanwhile, some conditions are derived to ensure that, in any designated region, the model has a locally exponentially stable or globally exponentially attractive periodic orbit located in it. As a special case of bi-periodicity, some results are also presented for the system with constant external inputs. Finally, four examples are given to illustrate the effectiveness of the obtained results.

Bi-periodicity evoked by periodic external inputs in delayed Cohen-Grossberg-type bidirectional associative memory networks

International Nuclear Information System (INIS)

Cao Jinde; Wang Yanyan

2010-01-01

In this paper, the bi-periodicity issue is discussed for Cohen-Grossberg-type (CG-type) bidirectional associative memory (BAM) neural networks (NNs) with time-varying delays and standard activation functions. It is shown that the model considered in this paper has two periodic orbits located in saturation regions and they are locally exponentially stable. Meanwhile, some conditions are derived to ensure that, in any designated region, the model has a locally exponentially stable or globally exponentially attractive periodic orbit located in it. As a special case of bi-periodicity, some results are also presented for the system with constant external inputs. Finally, four examples are given to illustrate the effectiveness of the obtained results.

Transport properties in monolayer-bilayer-monolayer graphene planar junctions

Institute of Scientific and Technical Information of China (English)

Kai-Long Chu; Zi-Bo Wang; Jiao-Jiao Zhou; Hua Jiang

2017-01-01

The transport study of graphene based junctions has become one of the focuses in graphene research.There are two stacking configurations for monolayer-bilayer-monolayer graphene planar junctions.One is the two monolayer graphene contacting the same side of the bilayer graphene,and the other is the two-monolayer graphene contacting the different layers of the bilayer graphene.In this paper,according to the Landauer-Büttiker formula,we study the transport properties of these two configurations.The influences of the local gate potential in each part,the bias potential in bilayer graphene,the disorder and external magnetic field on conductance are obtained.We find the conductances of the two configurations can be manipulated by all of these effects.Especially,one can distinguish the two stacking configurations by introducing the bias potential into the bilayer graphene.The strong disorder and the external magnetic field will make the two stacking configurations indistinguishable in the transport experiment.

About an Optimal Visiting Problem

Energy Technology Data Exchange (ETDEWEB)

Bagagiolo, Fabio, E-mail: bagagiol@science.unitn.it; Benetton, Michela [Unversita di Trento, Dipartimento di Matematica (Italy)

2012-02-15

In this paper we are concerned with the optimal control problem consisting in minimizing the time for reaching (visiting) a fixed number of target sets, in particular more than one target. Such a problem is of course reminiscent of the famous 'Traveling Salesman Problem' and brings all its computational difficulties. Our aim is to apply the dynamic programming technique in order to characterize the value function of the problem as the unique viscosity solution of a suitable Hamilton-Jacobi equation. We introduce some 'external' variables, one per target, which keep in memory whether the corresponding target is already visited or not, and we transform the visiting problem in a suitable Mayer problem. This fact allows us to overcome the lacking of the Dynamic Programming Principle for the originary problem. The external variables evolve with a hysteresis law and the Hamilton-Jacobi equation turns out to be discontinuous.

Cooperation in memory-based prisoner's dilemma game on interdependent networks

Science.gov (United States)

Luo, Chao; Zhang, Xiaolin; Liu, Hong; Shao, Rui

2016-05-01

Memory or so-called experience normally plays the important role to guide the human behaviors in real world, that is essential for rational decisions made by individuals. Hence, when the evolutionary behaviors of players with bounded rationality are investigated, it is reasonable to make an assumption that players in system are with limited memory. Besides, in order to unravel the intricate variability of complex systems in real world and make a highly integrative understanding of their dynamics, in recent years, interdependent networks as a comprehensive network structure have obtained more attention in this community. In this article, the evolution of cooperation in memory-based prisoner's dilemma game (PDG) on interdependent networks composed by two coupled square lattices is studied. Herein, all or part of players are endowed with finite memory ability, and we focus on the mutual influence of memory effect and interdependent network reciprocity on cooperation of spatial PDG. We show that the density of cooperation can be significantly promoted within an optimal region of memory length and interdependent strength. Furthermore, distinguished by whether having memory ability/external links or not, each kind of players on networks would have distinct evolutionary behaviors. Our work could be helpful to understand the emergence and maintenance of cooperation under the evolution of memory-based players on interdependent networks.

Stochastic memory: Memory enhancement due to noise

Science.gov (United States)

Stotland, Alexander; di Ventra, Massimiliano

2012-01-01

There are certain classes of resistors, capacitors, and inductors that, when subject to a periodic input of appropriate frequency, develop hysteresis loops in their characteristic response. Here we show that the hysteresis of such memory elements can also be induced by white noise of appropriate intensity even at very low frequencies of the external driving field. We illustrate this phenomenon using a physical model of memory resistor realized by TiO2 thin films sandwiched between metallic electrodes and discuss under which conditions this effect can be observed experimentally. We also discuss its implications on existing memory systems described in the literature and the role of colored noise.

Characterizing Memory Usage Behavior in Memory-related Code Changes

OpenAIRE

Wong, Howard Wah

2017-01-01

With the heavy memory pressure produced by multi-core systems and with memory per- formance trailing processor performance, today’s application developers need to consider the memory subsystem during software development. In particular, optimizing software re- quires a deep understanding of how the software uses the memory and how the hardware satisfies the memory requests. In order to accelerate development, programmers rely on soft- ware tools such as profilers for insightful analysis. Howe...

Non-planar ABJ theory and parity

International Nuclear Information System (INIS)

Caputa, Pawel; Kristjansen, Charlotte; Zoubos, Konstantinos

2009-01-01

While the ABJ Chern-Simons-matter theory and its string theory dual manifestly lack parity invariance, no sign of parity violation has so far been observed on the weak coupling spin chain side. In particular, the planar two-loop dilatation generator of ABJ theory is parity invariant. In this Letter we derive the non-planar part of the two-loop dilatation generator of ABJ theory in its SU(2)xSU(2) sub-sector. Applying the dilatation generator to short operators, we explicitly demonstrate that, for operators carrying excitations on both spin chains, the non-planar part breaks parity invariance. For operators with only one type of excitation, however, parity remains conserved at the non-planar level. We furthermore observe that, as for ABJM theory, the degeneracy between planar parity pairs is lifted when non-planar corrections are taken into account.

Non-planar ABJ Theory and Parity

DEFF Research Database (Denmark)

Caputa, Pawel; Kristjansen, Charlotte; Zoubos, Konstantinos

2009-01-01

we derive the non-planar part of the two-loop dilatation generator of ABJ theory in its SU(2)xSU(2) sub-sector. Applying the dilatation generator to short operators, we explicitly demonstrate that, for operators carrying excitations on both spin chains, the non-planar part breaks parity invariance......While the ABJ Chern-Simons-matter theory and its string theory dual manifestly lack parity invariance, no sign of parity violation has so far been observed on the weak coupling spin chain side. In particular, the planar two-loop dilatation generator of ABJ theory is parity invariant. In this letter....... For operators with only one type of excitation, however, parity remains conserved at the non-planar level. We furthermore observe that, as for ABJM theory, the degeneracy between planar parity pairs is lifted when non-planar corrections are taken into account....

Thin n-in-p planar pixel modules for the ATLAS upgrade at HL-LHC

International Nuclear Information System (INIS)

Savic, N.; Bergbreiter, L.; Breuer, J.; La Rosa, A.; Macchiolo, A.; Nisius, R.; Terzo, S.

2017-01-01

The ATLAS experiment will undergo a major upgrade of the tracker system in view of the high luminosity phase of the LHC (HL-LHC) foreseen to start around 2025. Thin planar pixel modules are promising candidates to instrument the new pixel system, thanks to the reduced contribution to the material budget and their high charge collection efficiency after irradiation. New designs of the pixel cells, with an optimized biasing structure, have been implemented in n-in-p planar pixel productions with sensor thicknesses of 270 μm. Using beam tests, the gain in hit efficiency is investigated as a function of the received irradiation fluence. The outlook for future thin planar pixel sensor productions will be discussed, with a focus on thin sensors with a thickness of 100 and 150 μm and a novel design with the optimized biasing structure and small pixel cells (50×50 and 25×100 μm"2). These dimensions are foreseen for the new ATLAS read-out chip in 65 nm CMOS technology and the fine segmentation will represent a challenge for the tracking in the forward region of the pixel system at HL-LHC. To predict the performance of 50×50 μm"2 pixels at high η, FE-I4 compatible planar pixel sensors have been studied before and after irradiation in beam tests at high incidence angle with respect to the short pixel direction. Results on cluster shapes, charge collection- and hit efficiency will be shown.

Thin n-in-p planar pixel modules for the ATLAS upgrade at HL-LHC

Energy Technology Data Exchange (ETDEWEB)

Savic, N., E-mail: natascha.savic@mpp.mpg.de; Bergbreiter, L.; Breuer, J.; La Rosa, A.; Macchiolo, A.; Nisius, R.; Terzo, S.

2017-02-11

The ATLAS experiment will undergo a major upgrade of the tracker system in view of the high luminosity phase of the LHC (HL-LHC) foreseen to start around 2025. Thin planar pixel modules are promising candidates to instrument the new pixel system, thanks to the reduced contribution to the material budget and their high charge collection efficiency after irradiation. New designs of the pixel cells, with an optimized biasing structure, have been implemented in n-in-p planar pixel productions with sensor thicknesses of 270 μm. Using beam tests, the gain in hit efficiency is investigated as a function of the received irradiation fluence. The outlook for future thin planar pixel sensor productions will be discussed, with a focus on thin sensors with a thickness of 100 and 150 μm and a novel design with the optimized biasing structure and small pixel cells (50×50 and 25×100 μm{sup 2}). These dimensions are foreseen for the new ATLAS read-out chip in 65 nm CMOS technology and the fine segmentation will represent a challenge for the tracking in the forward region of the pixel system at HL-LHC. To predict the performance of 50×50 μm{sup 2} pixels at high η, FE-I4 compatible planar pixel sensors have been studied before and after irradiation in beam tests at high incidence angle with respect to the short pixel direction. Results on cluster shapes, charge collection- and hit efficiency will be shown.

Electro-optical memory of a nematic liquid crystal doped by multi-walled carbon nanotubes

Directory of Open Access Journals (Sweden)

L. Dolgov

2012-10-01

Full Text Available A pronounced irreversible electro-optical response (memory effect has been recently observed for nematic liquid crystal (LC EBBA doped by multi-walled carbon nanotubes (MWCNTs near the percolation threshold of the MWCNTs (0.02÷0.05 wt. %. It is caused by irreversible homeotropic-to-planar reorientation of LC in an electric field. This feature is explained by electro-hydrodynamically stimulated dispergation of MWCNTs in LC and by the formation of a percolation MWCNT network which acts as a spatially distributed surface stabilizing the planar state of the LC. This mechanism is confirmed by the absence of memory in the EBBA/MWCNT composites, whose original structure is fixed by a polymer. The observed effect suggests new operation modes for the memory type and bistable LC devices, as well as a method for in situ dispergation of carbon nanotubes in LC cells.

Characterization of mechanical properties of pericardium tissue using planar biaxial tension and flexural deformation.

Science.gov (United States)

Murdock, Kyle; Martin, Caitlin; Sun, Wei

2018-01-01

Flexure is an important mode of deformation for native and bioprosthetic heart valves. However, mechanical characterization of bioprosthetic leaflet materials has been done primarily through planar tensile testing. In this study, an integrated experimental and computational cantilever beam bending test was performed to characterize the flexural properties of glutaraldehyde-treated bovine and porcine pericardium of different thicknesses. A strain-invariant based structural constitutive model was used to model the pericardial mechanical behavior quantified through the bending tests of this study and the planar biaxial tests previously performed. The model parameters were optimized through an inverse finite element (FE) procedure in order to describe both sets of experimental data. The optimized material properties were implemented in FE simulations of transcatheter aortic valve (TAV) deformation. It was observed that porcine pericardium TAV leaflets experienced significantly more flexure than bovine when subjected to opening pressurization, and that the flexure may be overestimated using a constitutive model derived from purely planar tensile experimental data. Thus, modeling of a combination of flexural and biaxial tensile testing data may be necessary to more accurately describe the mechanical properties of pericardium, and to computationally investigate bioprosthetic leaflet function and design. Copyright © 2017 Elsevier Ltd. All rights reserved.

SUBJECTIVE MEMORY IN OLDER AFRICAN AMERICANS

OpenAIRE

Sims, Regina C.; Whitfield, Keith E.; Ayotte, Brian J.; Gamaldo, Alyssa A.; Edwards, Christopher L.; Allaire, Jason C.

2011-01-01

The current analysis examined (a) if measures of psychological well-being predict subjective memory, and (b) if subjective memory is consistent with actual memory. Five hundred seventy-nine older African Americans from the Baltimore Study of Black Aging completed measures assessing subjective memory, depressive symptomatology, perceived stress, locus of control, and verbal and working memory. Higher levels of perceived stress and greater externalized locus of control predicted poorer subjecti...

Dynamic Neuromuscular Control of the Lower Limbs in Response to Unexpected Single-Planar versus Multi-Planar Support Perturbations in Young, Active Adults.

Science.gov (United States)

Malfait, Bart; Staes, Filip; de Vries, Aijse; Smeets, Annemie; Hawken, Malcolm; Robinson, Mark A; Vanrenterghem, Jos; Verschueren, Sabine

2015-01-01

An anterior cruciate ligament (ACL) injury involves a multi-planar injury mechanism. Nevertheless, unexpected multi-planar perturbations have not been used to screen athletes in the context of ACL injury prevention yet could reveal those more at risk. The objective of this study was to compare neuromuscular responses to multi-planar (MPP) and single-planar perturbations (SPP) during a stepping-down task. These results might serve as a basis for future implementation of external perturbations in ACL injury screening programs. Thirteen young adults performed a single leg stepping-down task in eight conditions (four MPP and four SPP with a specified amplitude and velocity). The amplitudes of vastus lateralis (VL), vastus medialis (VM), hamstrings lateralis (HL), hamstrings medialis (HM) EMG activity, medio-lateral and anterior-posterior centre of mass (COM) displacements, the peak knee flexion and abduction angles were compared between conditions using an one-way ANOVA. Number of stepping responses were monitored during all conditions. Significantly greater muscle activity levels were found in response to the more challenging MPP and SPP compared to the less challenging conditions (p neuromuscular activity were found between the MPP conditions and their equivalents in the SPP. Eighteen stepping responses were monitored in the SPP versus nine in the MPP indicating that the overall neuromuscular control was even more challenged during the SPP which was supported by greater COM displacements in the SPP. The more intense MPP and SPP evoked different neuromuscular responses resulting in greater muscle activity levels compared to small perturbations. Based on the results of COM displacements and based on the amount of stepping responses, dynamic neuromuscular control of the knee joint appeared less challenged during the MPP. Therefore, future work should investigate extensively if other neuromuscular differences (i.e. co-activation patterns and kinetics) exist between MPP

The optimal timing of stimulation to induce long-lasting positive effects on episodic memory in physiological aging.

Science.gov (United States)

Manenti, Rosa; Sandrini, Marco; Brambilla, Michela; Cotelli, Maria

2016-09-15

Episodic memory displays the largest degree of age-related decline. A noninvasive brain stimulation technique that can be used to modulate memory in physiological aging is transcranial Direct Current Stimulation (tDCS). However, an aspect that has not been adequately investigated in previous studies is the optimal timing of stimulation to induce long-lasting positive effects on episodic memory function. Our previous studies showed episodic memory enhancement in older adults when anodal tDCS was applied over the left lateral prefrontal cortex during encoding or after memory consolidation with or without a contextual reminder. Here we directly compared the two studies to explore which of the tDCS protocols would induce longer-lasting positive effects on episodic memory function in older adults. In addition, we aimed to determine whether subjective memory complaints would be related to the changes in memory performance (forgetting) induced by tDCS, a relevant issue in aging research since individuals with subjective memory complaints seem to be at higher risk of later memory decline. The results showed that anodal tDCS applied after consolidation with a contextual reminder induced longer-lasting positive effects on episodic memory, conceivably through reconsolidation, than anodal tDCS during encoding. Furthermore, we reported, providing new data, a moderate negative correlation between subjective memory complaints and forgetting when anodal tDCS was applied after consolidation with a contextual reminder. This study sheds light on the best-suited timing of stimulation to induce long-lasting positive effects on memory function and might help the clinicians to select the most effective tDCS protocol to prevent memory decline. Copyright © 2016 Elsevier B.V. All rights reserved.

Sewer Networks Optimization by Particle Swarm Optimization with Abilities of Fly-Back Mechanism and Harmony Memory

Directory of Open Access Journals (Sweden)

محسن نفیسی

2014-10-01

Full Text Available Lack of an efficient sewer network in urban areas threatens public health and may give rise to contagious diseases. Various optimization methods have been developed for use in designing sewers networks in response to a number of requirements such as the high costs of constructing sewer networks, financial limitations, the presence of both discrete and continuous decision variables, and the nonlinear time complexity of such design problems. In this study, the particle swarm optimization algorithm (PSO with the capability of “fly-back” mechanism equipped with the harmony search (HPSO is used for the optimization of sewers network designs. The objective function consists of minimizing the excavation and embedding costs of commercial pipes. The fly-back mechanism and the harmony memory method are used to prevent leaving out variables from the feasible space of the problem in an attempt to enhance model efficiency. Model constraints are satisfied at two levels, which leads to the desirable convergence of the PSO algorithm as compared to the conventional penalty methods in alternative evolutionary algorithms. In order to determine the admissible decision variables, the Manning equation is used as a hydraulic model. The performance of the proposed algorithm is shown by presenting two examples of sewer networks. Compared to the PSO algorithm used in sewer network optimization models, the proposed model exhibits a tangible improvement in cost reduction and a higher computational stability.

Planar graphs theory and algorithms

CERN Document Server

Nishizeki, T

1988-01-01

Collected in this volume are most of the important theorems and algorithms currently known for planar graphs, together with constructive proofs for the theorems. Many of the algorithms are written in Pidgin PASCAL, and are the best-known ones; the complexities are linear or 0(nlogn). The first two chapters provide the foundations of graph theoretic notions and algorithmic techniques. The remaining chapters discuss the topics of planarity testing, embedding, drawing, vertex- or edge-coloring, maximum independence set, subgraph listing, planar separator theorem, Hamiltonian cycles, and single- or multicommodity flows. Suitable for a course on algorithms, graph theory, or planar graphs, the volume will also be useful for computer scientists and graph theorists at the research level. An extensive reference section is included.

The effect of internal and external stress on two-way shape-memory behaviour in Co49Ni21.6Ga29.4 single crystals

International Nuclear Information System (INIS)

Liu, G D; Dai, X F; Luo, H Z; Liu, H Y; Meng, F B; Li, Y; Yu, X; Chen, J L; Wu, G H

2011-01-01

The effect of the internal stress on the two-way shape memory in Co 49 Ni 21.6 Ga 29.4 single crystals has been investigated. We found that the internal stress generated natively by the solidifying process works as a tensile force along the growth direction. Applying different compressive pre-stresses along the [0 0 1] direction, the shape-memory strain can be continuously changed from +1.0% to -2.3%. In the [1 1 0] direction, the strain monotonically increases from -2.0% to -4.0% due to a strong detwinning produced by the consistent effect of the external and internal stresses.

Reducing the influence of STI on SONOS memory through optimizing added boron implantation technology

International Nuclear Information System (INIS)

Xu Yue; Yan Feng; Li Zhiguo; Yang Fan; Wang Yonggang; Chang Jianguang

2010-01-01

The influence of shallow trench isolation (STI) on a 90 nm polysilicon-oxide-nitride-oxide-silicon structure non-volatile memory has been studied based on experiments. It has been found that the performance of edge memory cells adjacent to STI deteriorates remarkably. The compressive stress and boron segregation induced by STI are thought to be the main causes of this problem. In order to mitigate the STI impact, an added boron implantation in the STI region is developed as a new solution. Four kinds of boron implantation experiments have been implemented to evaluate the impact of STI on edge cells, respectively. The experimental results show that the performance of edge cells can be greatly improved through optimizing added boron implantation technology. (semiconductor devices)

Optimized ONO thickness for multi-level and 2-bit/cell operation for wrapped-select-gate (WSG) SONOS memory

International Nuclear Information System (INIS)

Wu, Woei-Cherng; Chao, Tien-Sheng; Yang, Tsung-Yu; Peng, Wu-Chin; Yang, Wen-Luh; Chen, Jian-Hao; Ma, Ming Wen; Lai, Chao-Sung; Lee, Chien-Hsing; Hsieh, Tsung-Min; Liou, Jhyy Cheng; Chen, Tzu Ping; Chen, Chien Hung; Lin, Chih Hung; Chen, Hwi Huang; Ko, Joe

2008-01-01

In this paper, highly reliable wrapped-select-gate (WSG) silicon–oxide–nitride–oxide–silicon (SONOS) memory cells with multi-level and 2-bit/cell operation have been successfully demonstrated. The source-side injection mechanism for WSG-SONOS memory with different ONO thickness was thoroughly investigated. The different programming efficiencies of the WSG-SONOS memory under different ONO thicknesses are explained by the lateral electrical field extracted from the simulation results. Furthermore, multi-level storage is easily obtained, and good V TH distribution presented, for the WSG-SONOS memory with optimized ONO thickness. High program/erase speed (10 µs/5 ms) and low programming current (3.5 µA) are used to achieve the multi-level operation with tolerable gate and drain disturbance, negligible second-bit effect, excellent data retention and good endurance performance

AIRGAMMA, External Gamma-Ray Exposure from Radioactive Cloud

International Nuclear Information System (INIS)

Hidaka, Akihide; Iijima, Tshinori

1989-01-01

1 - Description of program or function: AIRGAMMA calculates quickly the external exposure to gamma rays from a radioactive cloud. 2 - Method of solution: The external exposure is calculated by interpolating the normalized doses providing on the basis of the Gaussian plume model. 3 - Restrictions on the complexity of the problem: Memory requirement is 30 Kbytes

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

Directory of Open Access Journals (Sweden)

Konstantinos Kalaitzis

2016-10-01

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

Evaluation of Externality Costs in Life-Cycle Optimization of Municipal Solid Waste Management Systems

DEFF Research Database (Denmark)

Martinez Sanchez, Veronica; Levis, James W.; Damgaard, Anders

2017-01-01

The development of sustainable solid waste management (SWM) systems requires consideration of both economic and environmental impacts. Societal life-cycle costing (S-LCC) provides a quantitative framework to estimate both economic and environmental impacts, by including "budget costs...... suburban U.S. county of 500 000 people generating 320 000 Mg of waste annually. Estimated externality costs are based on emissions of CO2, CH4, N2O, PM2.5, PM10, NOx, SO2, VOC, CO, NH3, Hg, Pb, Cd, Cr (VI), Ni, As, and dioxins. The results indicate that incorporating S-LCC into optimized SWM strategy...... development encourages the use of a mixed waste material recovery facility with residues going to incineration, and separated organics to anaerobic digestion. Results are sensitive to waste composition, energy mix and recycling rates. Most of the externality costs stem from SO2, NOx, PM2.5, CH4, fossil CO2...

In vitro quantification of the performance of model-based mono-planar and bi-planar fluoroscopy for 3D joint kinematics estimation.

Science.gov (United States)

Tersi, Luca; Barré, Arnaud; Fantozzi, Silvia; Stagni, Rita

2013-03-01

Model-based mono-planar and bi-planar 3D fluoroscopy methods can quantify intact joints kinematics with performance/cost trade-off. The aim of this study was to compare the performances of mono- and bi-planar setups to a marker-based gold-standard, during dynamic phantom knee acquisitions. Absolute pose errors for in-plane parameters were lower than 0.6 mm or 0.6° for both mono- and bi-planar setups. Mono-planar setups resulted critical in quantifying the out-of-plane translation (error bi-planar in quantifying the rotation along bone longitudinal axis (error bi-planar (error comparable to bi-planar, but with halved computational costs, halved segmentation time and halved ionizing radiation dose. Bi-planar analysis better compensated for the out-of-plane uncertainty that is differently propagated to relative kinematics depending on the setup. To take its full benefits, the motion task to be investigated should be designed to maintain the joint inside the visible volume introducing constraints with respect to mono-planar analysis.

External equivalent type Ward aiming optimization studies in power systems; Equivalentes externos tipo Ward visando estudos de otimizacao em sistemas de potencia

Energy Technology Data Exchange (ETDEWEB)

Nepomuceno, Leonardo

1993-07-01

The execution of functions such as contingency analysis, optimization, reactive dispatch, etc, at the control centers requires appropriate models representing the non-observable parts (external system). The classical external equivalents have been developed considering basically the contingency analysis. This work points out the performance of the Extended Ward Equivalent (W.E.), which currently represents the state of art concerning reduced circuit based models. the work analyzes the W.E. response to changes occurred in optimization studied. Moreover, a new model, named INTERNAL REACTIVE WARD (WRINT), resulting from an adaptation of the W.E. is proposed focusing on the improvement of the equivalent in case of changes occurs in optimization studies. The model's general idea is to reflect the equivalent's capacity of reactive response into the internal system. Comparative computational test results are shown. The details of routines implementation are also pointed out. (author)

Minimizing the disruptive effects of prospective memory in simulated air traffic control.

Science.gov (United States)

Loft, Shayne; Smith, Rebekah E; Remington, Roger W

2013-09-01

Prospective memory refers to remembering to perform an intended action in the future. Failures of prospective memory can occur in air traffic control. In two experiments, we examined the utility of external aids for facilitating air traffic management in a simulated air traffic control task with prospective memory requirements. Participants accepted and handed-off aircraft and detected aircraft conflicts. The prospective memory task involved remembering to deviate from a routine operating procedure when accepting target aircraft. External aids that contained details of the prospective memory task appeared and flashed when target aircraft needed acceptance. In Experiment 1, external aids presented either adjacent or nonadjacent to each of the 20 target aircraft presented over the 40-min test phase reduced prospective memory error by 11% compared with a condition without external aids. In Experiment 2, only a single target aircraft was presented a significant time (39-42 min) after presentation of the prospective memory instruction, and the external aids reduced prospective memory error by 34%. In both experiments, costs to the efficiency of nonprospective memory air traffic management (nontarget aircraft acceptance response time, conflict detection response time) were reduced by nonadjacent aids compared with no aids or adjacent aids. In contrast, in both experiments, the efficiency of the prospective memory air traffic management (target aircraft acceptance response time) was facilitated by adjacent aids compared with nonadjacent aids. Together, these findings have potential implications for the design of automated alerting systems to maximize multitask performance in work settings where operators monitor and control demanding perceptual displays. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Coupling analysis of transcutaneous energy transfer coils with planar sandwich structure for a novel artificial anal sphincter

Institute of Scientific and Technical Information of China (English)

Lei KE; Guo-zheng YAN; Sheng YAN; Zhi-wu WANG; Da-sheng LIU

2014-01-01

This paper presents a set of analytical expressions used to determine the coupling coefficient between primary and secondary Litz-wire planar coils used in a transcutaneous energy transfer (TET) system. A TET system has been designed to power a novel elastic scaling artificial anal sphincter system (ES-AASS) for treating severe fecal incontinence (FI), a condition that would benefit from an optimized TET. Expressions that describe the geometrical dimension dependence of self- and mutual inductances of planar coils on a ferrite substrate are provided. The effects of ferrite substrate conductivity, relative permeability, and geometrical dimensions are also considered. To verify these expressions, mutual coupling between planar coils is computed by 3D finite element analysis (FEA), and the proposed expressions show good agreement with numerical results. Different types of planar coils are fabricated with or without ferrite substrate. Measured results for each of the cases are compared with theoretical predictions and FEA solutions. The theoretical results and FEA results are in good agreement with the experimental data.

Optimal inspection planning for onshore pipelines subject to external corrosion

International Nuclear Information System (INIS)

Gomes, Wellison J.S.; Beck, André T.; Haukaas, Terje

2013-01-01

Continuous operation of pipeline systems involves significant expenditures in inspection and maintenance activities. The cost-effective safety management of such systems involves allocating the optimal amount of resources to inspection and maintenance activities, in order to control risks (expected costs of failure). In this context, this article addresses the optimal inspection planning for onshore pipelines subject to external corrosion. The investigation addresses a challenging problem of practical relevance, and strives for using the best available models to describe random corrosion growth and the relevant limit state functions. A single pipeline segment is considered in this paper. Expected numbers of failures and repairs are evaluated by Monte Carlo sampling, and a novel procedure is employed to evaluate sensitivities of the objective function with respect to design parameters. This procedure is shown to be accurate and more efficient than finite differences. The optimum inspection interval is found for an example problem, and the robustness of this optimum to the assumed inspection and failure costs is investigated. It is shown that optimum total expected costs found herein are not highly sensitive to the assumed costs of inspection and failure. -- Highlights: • Inspection, repair and failure costs of pipeline systems considered. • Optimum inspection schedule (OIS) obtained by minimizing total expected life-cycle costs. • Robustness of OIS evaluated w.r.t. estimated costs of inspection and failure. • Accurate non-conservative models of corrosion growth employed

Memory effects for a stochastic fractional oscillator in a magnetic field

Science.gov (United States)

Mankin, Romi; Laas, Katrin; Laas, Tõnu; Paekivi, Sander

2018-01-01

The problem of random motion of harmonically trapped charged particles in a constant external magnetic field is studied. A generalized three-dimensional Langevin equation with a power-law memory kernel is used to model the interaction of Brownian particles with the complex structure of viscoelastic media (e.g., dusty plasmas). The influence of a fluctuating environment is modeled by an additive fractional Gaussian noise. In the long-time limit the exact expressions of the first-order and second-order moments of the fluctuating position for the Brownian particle subjected to an external periodic force in the plane perpendicular to the magnetic field have been calculated. Also, the particle's angular momentum is found. It is shown that an interplay of external periodic forcing, memory, and colored noise can generate a variety of cooperation effects, such as memory-induced sign reversals of the angular momentum, multiresonance versus Larmor frequency, and memory-induced particle confinement in the absence of an external trapping field. Particularly in the case without external trapping, if the memory exponent is lower than a critical value, we find a resonancelike behavior of the anisotropy in the particle position distribution versus the driving frequency, implying that it can be efficiently excited by an oscillating electric field. Similarities and differences between the behaviors of the models with internal and external noises are also discussed.

Curved planar reformation and optimal path tracing (CROP) method for false positive reduction in computer-aided detection of pulmonary embolism in CTPA

Science.gov (United States)

Zhou, Chuan; Chan, Heang-Ping; Guo, Yanhui; Wei, Jun; Chughtai, Aamer; Hadjiiski, Lubomir M.; Sundaram, Baskaran; Patel, Smita; Kuriakose, Jean W.; Kazerooni, Ella A.

2013-03-01

The curved planar reformation (CPR) method re-samples the vascular structures along the vessel centerline to generate longitudinal cross-section views. The CPR technique has been commonly used in coronary CTA workstation to facilitate radiologists' visual assessment of coronary diseases, but has not yet been used for pulmonary vessel analysis in CTPA due to the complicated tree structures and the vast network of pulmonary vasculature. In this study, a new curved planar reformation and optimal path tracing (CROP) method was developed to facilitate feature extraction and false positive (FP) reduction and improve our PE detection system. PE candidates are first identified in the segmented pulmonary vessels at prescreening. Based on Dijkstra's algorithm, the optimal path (OP) is traced from the pulmonary trunk bifurcation point to each PE candidate. The traced vessel is then straightened and a reformatted volume is generated using CPR. Eleven new features that characterize the intensity, gradient, and topology are extracted from the PE candidate in the CPR volume and combined with the previously developed 9 features to form a new feature space for FP classification. With IRB approval, CTPA of 59 PE cases were retrospectively collected from our patient files (UM set) and 69 PE cases from the PIOPED II data set with access permission. 595 and 800 PEs were manually marked by experienced radiologists as reference standard for the UM and PIOPED set, respectively. At a test sensitivity of 80%, the average FP rate was improved from 18.9 to 11.9 FPs/case with the new method for the PIOPED set when the UM set was used for training. The FP rate was improved from 22.6 to 14.2 FPs/case for the UM set when the PIOPED set was used for training. The improvement in the free response receiver operating characteristic (FROC) curves was statistically significant (p<0.05) by JAFROC analysis, indicating that the new features extracted from the CROP method are useful for FP reduction.

Eavesdropping without quantum memory

International Nuclear Information System (INIS)

Bechmann-Pasquinucci, H.

2006-01-01

In quantum cryptography the optimal eavesdropping strategy requires that the eavesdropper uses ancillas and quantum memories in order to optimize her information. What happens if the eavesdropper has no quantum memory? It is shown that in this case the eavesdropper obtains a better information/disturbance trade-off by adopting the simple intercept/resend strategy

Consumable Process Development for Chemical Mechanical Planarization of Bit Patterned Media for Magnetic Storage Fabrication

Science.gov (United States)

Bonivel, Joseph T., Jr.

2010-09-01

As the superparamagnetic limit is reached, the magnetic storage industry looks to circumvent the barrier by implementing patterned media (PM) as a viable means to store and access data. Chemical mechanical polishing (CMP) is a semiconductor fabrication technique used to planarize surfaces and is investigated as a method to ensure that the PM is polished to surface roughness parameters that allow the magnetic read/write head to move seamlessly across the PM. Results from this research have implications in feasibility studies of utilizing CMP as the main planarization technique for PM fabrication. Benchmark data on the output parameters of the CMP process, for bit patterned media (BPM), based on the machine process parameters, pad properties, and slurry characteristics are optimized. The research was conducted in a systematic manner in which the optimized parameters for each phase are utilized in future phases. The optimum results from each of the phases provide an overall optimum characterization for BPM CMP. Results on the CMP machine input parameters indicate that for optimal surface roughness and material removal, low polish pressures and high velocities should be used on the BPM. Pad characteristics were monitored by non destructive technique and results indicate much faster deterioration of all padcharacteristics versus polish time of BPM when compared to IC CMP. The optimum pad for PM polishing was the IC 1400 dual layer Suba V pad with a shore hardness of 57, and a k-groove pattern. The final phase of polishing evaluated the slurry polishing properties and novel nanodiamond (ND) slurry was created and benchmarked on BPM. The resulting CMP output parameters were monitored and neither the ND slurry nor the thermally responsive polymer slurry performed better than the commercially available Cabot iCue slurry for MRR or surface roughness. Research results indicate CMP is a feasible planarization technique for PM fabrication, but successful implementation of CMP

Frontside-micromachined planar piezoresistive vibration sensor: Evaluating performance in the low frequency test range

Directory of Open Access Journals (Sweden)

Lan Zhang

2014-01-01

Full Text Available Using a surface piezoresistor diffusion method and front-side only micromachining process, a planar piezoresistive vibration sensor was successfully developed with a simple structure, lower processing cost and fewer packaging difficulties. The vibration sensor had a large sector proof mass attached to a narrow flexure. Optimization of the boron diffusion piezoresistor placed on the edge of the narrow flexure greatly improved the sensitivity. Planar vibration sensors were fabricated and measured in order to analyze the effects of the sensor dimensions on performance, including the values of flexure width and the included angle of the sector. Sensitivities of fabricated planar sensors of 0.09–0.46 mV/V/g were measured up to a test frequency of 60 Hz. The sensor functioned at low voltages (<3 V and currents (<1 mA with a high sensitivity and low drift. At low background noise levels, the sensor had performance comparable to a commercial device.

Frontside-micromachined planar piezoresistive vibration sensor: Evaluating performance in the low frequency test range

Energy Technology Data Exchange (ETDEWEB)

Zhang, Lan; Lu, Jian, E-mail: jian-lu@aist.go.jp; Takagi, Hideki; Maeda, Ryutaro [Research Center for Ubiquitous MEMS and Micro Engineering (UMEMSME), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba, Ibaraki, 305-8564 (Japan)

2014-01-15

Using a surface piezoresistor diffusion method and front-side only micromachining process, a planar piezoresistive vibration sensor was successfully developed with a simple structure, lower processing cost and fewer packaging difficulties. The vibration sensor had a large sector proof mass attached to a narrow flexure. Optimization of the boron diffusion piezoresistor placed on the edge of the narrow flexure greatly improved the sensitivity. Planar vibration sensors were fabricated and measured in order to analyze the effects of the sensor dimensions on performance, including the values of flexure width and the included angle of the sector. Sensitivities of fabricated planar sensors of 0.09–0.46 mV/V/g were measured up to a test frequency of 60 Hz. The sensor functioned at low voltages (<3 V) and currents (<1 mA) with a high sensitivity and low drift. At low background noise levels, the sensor had performance comparable to a commercial device.

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.)

Exploring memory hierarchy design with emerging memory technologies

CERN Document Server

Sun, Guangyu

2014-01-01

This book equips readers with tools for computer architecture of high performance, low power, and high reliability memory hierarchy in computer systems based on emerging memory technologies, such as STTRAM, PCM, FBDRAM, etc.  The techniques described offer advantages of high density, near-zero static power, and immunity to soft errors, which have the potential of overcoming the “memory wall.”  The authors discuss memory design from various perspectives: emerging memory technologies are employed in the memory hierarchy with novel architecture modification;  hybrid memory structure is introduced to leverage advantages from multiple memory technologies; an analytical model named “Moguls” is introduced to explore quantitatively the optimization design of a memory hierarchy; finally, the vulnerability of the CMPs to radiation-based soft errors is improved by replacing different levels of on-chip memory with STT-RAMs.   ·         Provides a holistic study of using emerging memory technologies i...

A hybrid filtering approach for storage optimization in main-memory cloud database

Directory of Open Access Journals (Sweden)

Ghada M. Afify

2015-11-01

Full Text Available Enterprises and cloud service providers face dramatic increase in the amount of data stored in private and public clouds. Thus, data storage costs are growing hastily because they use only one single high-performance storage tier for storing all cloud data. There’s considerable potential to reduce cloud costs by classifying data into active (hot and inactive (cold. In the main-memory databases research, recent works focus on approaches to identify hot/cold data. Most of these approaches track tuple accesses to identify hot/cold tuples. In contrast, we introduce a novel Hybrid Filtering Approach (HFA that tracks both tuples and columns accesses in main-memory databases. Our objective is to enhance the performance in terms of three dimensions: storage space, query elapsed time and CPU time. In order to validate the effectiveness of our approach, we realized its concrete implementation on Hekaton, a SQL’s server memory-optimized engine using the well-known TPC-H benchmark. Experimental results show that the proposed HFA outperforms Hekaton approach in respect of all performance dimensions. In specific, HFA reduces the storage space by average of 44–96%, reduces the query elapsed time by average of 25–93% and reduces the CPU time by average of 31–97% compared to the traditional database approach.

Dynamic Memory Model for Non-Stationary Optimization

DEFF Research Database (Denmark)

Bendtsen, Claus Nørgaard; Krink, Thiemo

2002-01-01

Real-world problems are often nonstationary and can cause cyclic, repetitive patterns in the search landscape. For this class of problems, we introduce a new GA with dynamic explicit memory, which showed superior performance compared to a classic GA and a previously introduced memory-based GA for...

External equivalent type Ward aiming optimization studies in power systems; Equivalentes externos tipo Ward visando estudos de otimizacao em sistemas de potencia

Energy Technology Data Exchange (ETDEWEB)

Nepomuceno, Leonardo

1993-07-01

The execution of functions such as contingency analysis, optimization, reactive dispatch, etc, at the control centers requires appropriate models representing the non-observable parts (external system). The classical external equivalents have been developed considering basically the contingency analysis. This work points out the performance of the Extended Ward Equivalent (W.E.), which currently represents the state of art concerning reduced circuit based models. the work analyzes the W.E. response to changes occurred in optimization studied. Moreover, a new model, named INTERNAL REACTIVE WARD (WRINT), resulting from an adaptation of the W.E. is proposed focusing on the improvement of the equivalent in case of changes occurs in optimization studies. The model's general idea is to reflect the equivalent's capacity of reactive response into the internal system. Comparative computational test results are shown. The details of routines implementation are also pointed out. (author)

Dielectric response of planar relativistic quantum plasmas

International Nuclear Information System (INIS)

Bardos, D.C.; Frankel, N.E.

1991-01-01

The dielectric response of planar relativistic charged particle-antiparticle plasmas is investigated, treating Fermi and Bose plasmas. The conductivity tensor in each case is derived in the self-consistent Random Phase Approximation. The tensors are then evaluated at zero temperature for the case of no external fields, leading to explicit dispersion relations for the electrodynamic modes of the plasma. The longitudinal and transverse modes are in general coupled for plasma layers. This coupling vanishes, however, in the zero field case, allowing 'effective' longitudinal and transverse dielectric functions to be defined in terms of components of the conductivity tensor. Solutions to the longitudinal mode equations (i.e. plasmon modes) are exhibited, while purely transverse modes are found not to exist. In the case of the Bose plasma the screening of a test charge is investigated in detail. 41 refs., 1 fig

Optimization of Apparatus Design and Behavioral Measures for the Assessment of Visuo-Spatial Learning and Memory of Mice on the Barnes Maze

Science.gov (United States)

O'Leary, Timothy P.; Brown, Richard E.

2013-01-01

We have previously shown that apparatus design can affect visual-spatial cue use and memory performance of mice on the Barnes maze. The present experiment extends these findings by determining the optimal behavioral measures and test procedure for analyzing visuo-spatial learning and memory in three different Barnes maze designs. Male and female…

Single-event burnout hardening of planar power MOSFET with partially widened trench source

Science.gov (United States)

Lu, Jiang; Liu, Hainan; Cai, Xiaowu; Luo, Jiajun; Li, Bo; Li, Binhong; Wang, Lixin; Han, Zhengsheng

2018-03-01

We present a single-event burnout (SEB) hardened planar power MOSFET with partially widened trench sources by three-dimensional (3D) numerical simulation. The advantage of the proposed structure is that the work of the parasitic bipolar transistor inherited in the power MOSFET is suppressed effectively due to the elimination of the most sensitive region (P-well region below the N+ source). The simulation result shows that the proposed structure can enhance the SEB survivability significantly. The critical value of linear energy transfer (LET), which indicates the maximum deposited energy on the device without SEB behavior, increases from 0.06 to 0.7 pC/μm. The SEB threshold voltage increases to 120 V, which is 80% of the rated breakdown voltage. Meanwhile, the main parameter characteristics of the proposed structure remain similar with those of the conventional planar structure. Therefore, this structure offers a potential optimization path to planar power MOSFET with high SEB survivability for space and atmospheric applications. Project supported by the National Natural Science Foundation of China (Nos. 61404161, 61404068, 61404169).

Development and test of a planar R-band accelerating structure

CERN Document Server

Merte, R; Peikert, M; Yu, D

1999-01-01

Planar accelerating structures, so called muffin tins, are of great interest for new accelerating techniques which are operating at high frequencies. At present the upper frequency limit for high power sources is 29.9855 GHz available at CERN. Therefore a new design of a planar traveling wave constant impedance accelerating structure is presented. A fully engineered 37-cell prototype with an operating frequency of 29.9855 GHz, which is designed for the 2 pi /3-mode, was fabricated by CNC milling technology. The design includes a power coupler, a cavity geometry optimized to compensate the effect of transverse forces, vacuum flanges and beam pipe flanges. Shown are the frequency scan of transmission and reflection measurements compared to numerical simulations with GdfidL. Further, a non resonant bead pull measurement was made to determine and verify the fundamental modes of the structure. The cavity is planned to be powered at the CLIC test stand at CERN. (4 refs).

Optimizing a Drone Network to Deliver Automated External Defibrillators.

Science.gov (United States)

Boutilier, Justin J; Brooks, Steven C; Janmohamed, Alyf; Byers, Adam; Buick, Jason E; Zhan, Cathy; Schoellig, Angela P; Cheskes, Sheldon; Morrison, Laurie J; Chan, Timothy C Y

2017-06-20

Public access defibrillation programs can improve survival after out-of-hospital cardiac arrest, but automated external defibrillators (AEDs) are rarely available for bystander use at the scene. Drones are an emerging technology that can deliver an AED to the scene of an out-of-hospital cardiac arrest for bystander use. We hypothesize that a drone network designed with the aid of a mathematical model combining both optimization and queuing can reduce the time to AED arrival. We applied our model to 53 702 out-of-hospital cardiac arrests that occurred in the 8 regions of the Toronto Regional RescuNET between January 1, 2006, and December 31, 2014. Our primary analysis quantified the drone network size required to deliver an AED 1, 2, or 3 minutes faster than historical median 911 response times for each region independently. A secondary analysis quantified the reduction in drone resources required if RescuNET was treated as a large coordinated region. The region-specific analysis determined that 81 bases and 100 drones would be required to deliver an AED ahead of median 911 response times by 3 minutes. In the most urban region, the 90th percentile of the AED arrival time was reduced by 6 minutes and 43 seconds relative to historical 911 response times in the region. In the most rural region, the 90th percentile was reduced by 10 minutes and 34 seconds. A single coordinated drone network across all regions required 39.5% fewer bases and 30.0% fewer drones to achieve similar AED delivery times. An optimized drone network designed with the aid of a novel mathematical model can substantially reduce the AED delivery time to an out-of-hospital cardiac arrest event. © 2017 American Heart Association, Inc.

Optimization of transport suppression barriers generated by externally driven Alfven waves in D-shaped, low aspect ratio tokamaks

International Nuclear Information System (INIS)

Bruma, C; Cuperman, S; Komoshvili, K

2003-01-01

In an effort to optimize the internal transport barriers (ITBs) generated by externally launched mode-converted fast waves (FWs) in pre-heated spherical tokamaks (STs), we have carried out a systematic parametric investigation with respect to the rf waves and antenna characteristics; as a study case, a START-like device has been considered. Within the framework of a plasma model including both kinetic effects (collisionless Landau damping on passing electrons) and collisional damping on both trapped and passing electrons and ions, and starting with the solution of the full wave equation for a ST-plasma, we show that optimized ITBs, suitable for the stabilization of plasma turbulence (e.g. overpassing the maximum growth rate of the ITG-instability, γ ITG ) in STs can be generated by the aid of externally launched FW and mode-converted to kinetic Alfven waves. This result holds in spite of the limiting trapped-particles associated squeezing factor S present in the non-linear equation for E r (via the viscosity coefficient μ θi ∝|S| 3/2 , S = S(dE r /dr))

Optimizing performance through intrinsic motivation and attention for learning: The OPTIMAL theory of motor learning.

Science.gov (United States)

Wulf, Gabriele; Lewthwaite, Rebecca

2016-10-01

Effective motor performance is important for surviving and thriving, and skilled movement is critical in many activities. Much theorizing over the past few decades has focused on how certain practice conditions affect the processing of task-related information to affect learning. Yet, existing theoretical perspectives do not accommodate significant recent lines of evidence demonstrating motivational and attentional effects on performance and learning. These include research on (a) conditions that enhance expectancies for future performance, (b) variables that influence learners' autonomy, and (c) an external focus of attention on the intended movement effect. We propose the OPTIMAL (Optimizing Performance through Intrinsic Motivation and Attention for Learning) theory of motor learning. We suggest that motivational and attentional factors contribute to performance and learning by strengthening the coupling of goals to actions. We provide explanations for the performance and learning advantages of these variables on psychological and neuroscientific grounds. We describe a plausible mechanism for expectancy effects rooted in responses of dopamine to the anticipation of positive experience and temporally associated with skill practice. Learner autonomy acts perhaps largely through an enhanced expectancy pathway. Furthermore, we consider the influence of an external focus for the establishment of efficient functional connections across brain networks that subserve skilled movement. We speculate that enhanced expectancies and an external focus propel performers' cognitive and motor systems in productive "forward" directions and prevent "backsliding" into self- and non-task focused states. Expected success presumably breeds further success and helps consolidate memories. We discuss practical implications and future research directions.

Scaling Techniques for Massive Scale-Free Graphs in Distributed (External) Memory

KAUST Repository

Pearce, Roger; Gokhale, Maya; Amato, Nancy M.

2013-01-01

We present techniques to process large scale-free graphs in distributed memory. Our aim is to scale to trillions of edges, and our research is targeted at leadership class supercomputers and clusters with local non-volatile memory, e.g., NAND Flash

A novel bonding method for fabrication of PET planar nanofluidic chip with low dimension loss and high bonding strength

International Nuclear Information System (INIS)

Yin, Zhifu; Zou, Helin; Sun, Lei; Xu, Shenbo; Qi, Liping

2015-01-01

Plastic planar nanofluidic chips are becoming increasingly important for biological and chemical applications. However, the majority of the present bonding methods for planar nanofluidic chips suffer from high dimension loss and low bonding strength. In this work, a novel thermal bonding technique based on O 2 plasma and ethanol treatment was proposed. With the assistance of O 2 plasma and ethanol, the PET (polyethylene terephthalate) planar nanofluidic chip can be bonded at a low bonding temperature of 50 °C. To increase the bonding rate and bonding strength, the O 2 plasma parameters and thermal bonding parameters were optimized during the bonding process. The tensile test indicates that the bonding strength of the PET planar nanofluidic chip can reach 0.954 MPa, while the auto-fluorescence test demonstrates that there is no leakage or blockage in any of the bonded micro- or nanochannels. (paper)

Development of a bio-mechanical model of the spine based on 3D internal-external relationships: bi-planar radiography and Moire fringes

International Nuclear Information System (INIS)

Saunier-Koell, P.

2010-11-01

Nowadays, radiography is the gold standard for the follow up of spinal pathologies. Furthermore, bi-planar radiography allows the assessment of vertebrae configuration, by 3-dimensional (3D) reconstruction. However, multiple radiographic examinations during childhood and adolescence increase the risk of breast cancer among women. To reduce radiation doses, some radiographic assessments could be replaced by the back surface evaluation. This kind of non-invasive procedure allows for acquisition of many clinical parameters useful for spinal pathologies diagnosis and follow-up. Moreover, with an appropriate bio mechanical model, the back surface measurements could be used to estimate the spine configuration. The aim of this thesis is to develop and implement such a model based on personalized internal and external data. The Biomod 3S device has been developed by the company AXS MEDICAL SAS, Bordeaux, France. It offers the possibility of simultaneous acquisitions of X-rays and Moire fringes to obtain 3D reconstructions of the spine and the back surface. Such acquisitions on fifteen scoliotic subjects have enabled us to assess several relationships between internal 3D parameters (for example axial rotation of vertebrae) and external 3D parameters (for example rib hump). The spine configuration and the back surface obtained during this acquisition will also be used as initial position to develop (with Scilab) the multi-body model. The other data used by the model are the back surface in a second position and constraints obtained from the surface in both positions (for example displacement of C7 vertebra). The model has been validated on nine healthy subjects, whose 3D spine and back surface were reconstructed in several positions (standing, leaning forward, sitting) from MRI acquisitions. Moreover, the model has been operated on a pathological subject. This work has explored and utilized many spine and back surface information and leads the way to non-invasive diagnosis

A Survey of Phase Change Memory Systems

Institute of Scientific and Technical Information of China (English)

夏飞; 蒋德钧; 熊劲; 孙凝晖

2015-01-01

As the scaling of applications increases, the demand of main memory capacity increases in order to serve large working set. It is difficult for DRAM (dynamic random access memory) based memory system to satisfy the memory capacity requirement due to its limited scalability and high energy consumption. Compared to DRAM, PCM (phase change memory) has better scalability, lower energy leakage, and non-volatility. PCM memory systems have become a hot topic of academic and industrial research. However, PCM technology has the following three drawbacks: long write latency, limited write endurance, and high write energy, which raises challenges to its adoption in practice. This paper surveys architectural research work to optimize PCM memory systems. First, this paper introduces the background of PCM. Then, it surveys research efforts on PCM memory systems in performance optimization, lifetime improving, and energy saving in detail, respectively. This paper also compares and summarizes these techniques from multiple dimensions. Finally, it concludes these optimization techniques and discusses possible research directions of PCM memory systems in future.

Design of coated standing nanowire array solar cell performing beyond the planar efficiency limits

Energy Technology Data Exchange (ETDEWEB)

Zeng, Yang; Ye, Qinghao; Shen, Wenzhong, E-mail: wzshen@sjtu.edu.cn [Institute of Solar Energy, and Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Department of Physics and Astronomy, Shanghai Jiao Tong University, Shanghai 200240 (China)

2016-05-28

The single standing nanowire (SNW) solar cells have been proven to perform beyond the planar efficiency limits in both open-circuit voltage and internal quantum efficiency due to the built-in concentration and the shifting of the absorption front. However, the expandability of these nano-scale units to a macro-scale photovoltaic device remains unsolved. The main difficulty lies in the simultaneous preservation of an effective built-in concentration in each unit cell and a broadband high absorption capability of their array. Here, we have provided a detailed theoretical guideline for realizing a macro-scale solar cell that performs furthest beyond the planar limits. The key lies in a complementary design between the light-trapping of the single SNWs and that of the photonic crystal slab formed by the array. By tuning the hybrid HE modes of the SNWs through the thickness of a coaxial dielectric coating, the optimized coated SNW array can sustain an absorption rate over 97.5% for a period as large as 425 nm, which, together with the inherited carrier extraction advantage, leads to a cell efficiency increment of 30% over the planar limit. This work has demonstrated the viability of a large-size solar cell that performs beyond the planar limits.

Planarity constrained multi-view depth map reconstruction for urban scenes

Science.gov (United States)

Hou, Yaolin; Peng, Jianwei; Hu, Zhihua; Tao, Pengjie; Shan, Jie

2018-05-01

Multi-view depth map reconstruction is regarded as a suitable approach for 3D generation of large-scale scenes due to its flexibility and scalability. However, there are challenges when this technique is applied to urban scenes where apparent man-made regular shapes may present. To address this need, this paper proposes a planarity constrained multi-view depth (PMVD) map reconstruction method. Starting with image segmentation and feature matching for each input image, the main procedure is iterative optimization under the constraints of planar geometry and smoothness. A set of candidate local planes are first generated by an extended PatchMatch method. The image matching costs are then computed and aggregated by an adaptive-manifold filter (AMF), whereby the smoothness constraint is applied to adjacent pixels through belief propagation. Finally, multiple criteria are used to eliminate image matching outliers. (Vertical) aerial images, oblique (aerial) images and ground images are used for qualitative and quantitative evaluations. The experiments demonstrated that the PMVD outperforms the popular multi-view depth map reconstruction with an accuracy two times better for the aerial datasets and achieves an outcome comparable to the state-of-the-art for ground images. As expected, PMVD is able to preserve the planarity for piecewise flat structures in urban scenes and restore the edges in depth discontinuous areas.

Piecewise planar Möbius bands

DEFF Research Database (Denmark)

Gravesen, Jens

2005-01-01

t is shown that a closed polygon with an odd number of vertices is the median of exactly one piecewise planar cylinder and one piecewise planar Möbius band, intersecting each other orthogonally. A closed polygon with an even number of vertices is in the generic case neither the median...

Recall Performance for Content-Addressable Memory Using Adiabatic Quantum Optimization

Energy Technology Data Exchange (ETDEWEB)

Imam, Neena [ORNL; Humble, Travis S. [ORNL; McCaskey, Alex [ORNL; Schrock, Jonathan [ORNL; Hamilton, Kathleen E. [ORNL

2017-09-01

A content-addressable memory (CAM) stores key-value associations such that the key is recalled by providing its associated value. While CAM recall is traditionally performed using recurrent neural network models, we show how to solve this problem using adiabatic quantum optimization. Our approach maps the recurrent neural network to a commercially available quantum processing unit by taking advantage of the common underlying Ising spin model. We then assess the accuracy of the quantum processor to store key-value associations by quantifying recall performance against an ensemble of problem sets. We observe that different learning rules from the neural network community influence recall accuracy but performance appears to be limited by potential noise in the processor. The strong connection established between quantum processors and neural network problems supports the growing intersection of these two ideas.

Kinetic memory based on the enzyme-limited competition.

Science.gov (United States)

Hatakeyama, Tetsuhiro S; Kaneko, Kunihiko

2014-08-01

Cellular memory, which allows cells to retain information from their environment, is important for a variety of cellular functions, such as adaptation to external stimuli, cell differentiation, and synaptic plasticity. Although posttranslational modifications have received much attention as a source of cellular memory, the mechanisms directing such alterations have not been fully uncovered. It may be possible to embed memory in multiple stable states in dynamical systems governing modifications. However, several experiments on modifications of proteins suggest long-term relaxation depending on experienced external conditions, without explicit switches over multi-stable states. As an alternative to a multistability memory scheme, we propose "kinetic memory" for epigenetic cellular memory, in which memory is stored as a slow-relaxation process far from a stable fixed state. Information from previous environmental exposure is retained as the long-term maintenance of a cellular state, rather than switches over fixed states. To demonstrate this kinetic memory, we study several models in which multimeric proteins undergo catalytic modifications (e.g., phosphorylation and methylation), and find that a slow relaxation process of the modification state, logarithmic in time, appears when the concentration of a catalyst (enzyme) involved in the modification reactions is lower than that of the substrates. Sharp transitions from a normal fast-relaxation phase into this slow-relaxation phase are revealed, and explained by enzyme-limited competition among modification reactions. The slow-relaxation process is confirmed by simulations of several models of catalytic reactions of protein modifications, and it enables the memorization of external stimuli, as its time course depends crucially on the history of the stimuli. This kinetic memory provides novel insight into a broad class of cellular memory and functions. In particular, applications for long-term potentiation are discussed

Improved Dynamic Planar Point Location

DEFF Research Database (Denmark)

Brodal, Gerth Stølting; Arge, Lars; Georgiadis, Loukas

2006-01-01

We develop the first linear-space data structures for dynamic planar point location in general subdivisions that achieve logarithmic query time and poly-logarithmic update time.......We develop the first linear-space data structures for dynamic planar point location in general subdivisions that achieve logarithmic query time and poly-logarithmic update time....

Morphological Control for High Performance, Solution-Processed Planar Heterojunction Perovskite Solar Cells

KAUST Repository

Eperon, Giles E.

2013-09-09

Organometal trihalide perovskite based solar cells have exhibited the highest efficiencies to-date when incorporated into mesostructured composites. However, thin solid films of a perovskite absorber should be capable of operating at the highest efficiency in a simple planar heterojunction configuration. Here, it is shown that film morphology is a critical issue in planar heterojunction CH3NH3PbI3-xCl x solar cells. The morphology is carefully controlled by varying processing conditions, and it is demonstrated that the highest photocurrents are attainable only with the highest perovskite surface coverages. With optimized solution based film formation, power conversion efficiencies of up to 11.4% are achieved, the first report of efficiencies above 10% in fully thin-film solution processed perovskite solar cells with no mesoporous layer. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Planar impact experiments for EOS measurements

International Nuclear Information System (INIS)

Furnish, M.D.

1993-01-01

The community concerned with the numerical modeling of groundshock produced by underground nuclear tests must have access to materials data to benchmark models of rock behavior. Historically the primary source of these data has been planar impact experiments. These experiments have involved gun, explosive and electrical launchers. Other methods of introducing planar shocks include shock driving by in-contact explosives or laser bursts. This paper briefly describes gun launcher-based planar impact methods used to characterize geological materials at Sandia National Laboratories

Optimization of C20 isomers structure

International Nuclear Information System (INIS)

Ndjaka, J.M.B.; Charlier, J.C.

2001-07-01

We have performed geometry optimization of various possible planar and three-dimensional C 20 geometries. The planar structures considered include a linear chain, a monoclinic ring, and a bicyclic bow tie; while the three-dimensional geometric; consisted of a bowl or corranulene structure and a fullerene cage. In agreement with Wang et al MP2's calculations, our results predict the corranulene bowl to be the lowest energy structure. From the ground state geometry to the highest energy, considered C 20 structures, listed in increasing energy, are bowl, cage, bow tie, ring and chain. For the ring and bow tie isomers, the shape of the optimized structure deviates from that of the initial configuration; while the shape of the optimised bowl, cage and chain remain unchanged. (author)

Hysteresis Curve Fitting Optimization of Magnetic Controlled Shape Memory Alloy Actuator

Directory of Open Access Journals (Sweden)

Fuquan Tu

2016-11-01

Full Text Available As a new actuating material, magnetic controlled shape memory alloys (MSMAs have excellent characteristics such as a large output strain, fast response, and high energy density. These excellent characteristics are very attractive for precision positioning systems. However, the availability of MSMAs in practical precision positioning is poor, caused by weak repeatability under a certain stimulus. This problem results from the error of a large magnetic hysteresis in an external magnetic field. A suitable hysteresis modelling method can reduce the error and improve the accuracy of the MSMA actuator. After analyzing the original hysteresis modelling methods, three kinds of hysteresis modelling methods are proposed: least squares method, back propagation (BP artificial neural network, and BP artificial neural network based on genetic algorithms. Comparing the accuracy and convergence rate of three kinds of hysteresis modelling methods, the results show that the convergence rate of least squares method is the fastest, and the convergence accuracy of BP artificial neural networks based on genetic algorithms is the highest.

Optimal Software Strategies in the Presence of Network Externalities

Science.gov (United States)

Liu, Yipeng

2009-01-01

Network externalities or alternatively termed network effects are pervasive in computer software markets. While software vendors consider pricing strategies, they must also take into account the impact of network externalities on their sales. My main interest in this research is to describe a firm's strategies and behaviors in the presence of…

Shape memory materials

Institute of Scientific and Technical Information of China (English)

无

2001-01-01

Compared with piezoelectric ceramics and magnetostrictive materials, the shape memory materials possess larger recoverable strain and recovery stress but slower response to external field. It is expected that the magneto-shape memory materials may develop considerable strain as well as rapid and precise shape control. Pseudoelasticity and shape memory effect (SME) resulted from martensitic transformation and its reverse transformation in shape memory materials were generally described. The requirements of appearing the shape memory effect in materials and the criteria for thermoelastic martensitic transformation were given. Some aspects concerning characteristics of martensitic transformation, and factors affecting SME in Ni-Ti, Cu-Zn-Al and Fe-Mn-Si based alloys as well as ZrO2 containing ceramics were briefly reviewed. Thermodynamic calculation of Ms temperature as function of grain size and parent ordering in Cu-Zn-Al was presented. The works on prediction of Ms in Fe-Mn-Si based alloys and in ZrO2-CeO2 were mentioned. Magnetic shape memory materials were briefly introduced.

Dynamic memory management for embedded systems

CERN Document Server

Atienza Alonso, David; Poucet, Christophe; Peón-Quirós, Miguel; Bartzas, Alexandros; Catthoor, Francky; Soudris, Dimitrios

2015-01-01

This book provides a systematic and unified methodology, including basic principles and reusable processes, for dynamic memory management (DMM) in embedded systems.  The authors describe in detail how to design and optimize the use of dynamic memory in modern, multimedia and network applications, targeting the latest generation of portable embedded systems, such as smartphones. Coverage includes a variety of design and optimization topics in electronic design automation of DMM, from high-level software optimization to microarchitecture-level hardware support. The authors describe the design of multi-layer dynamic data structures for the final memory hierarchy layers of the target portable embedded systems and how to create a low-fragmentation, cost-efficient, dynamic memory management subsystem out of configurable components for the particular memory allocation and de-allocation patterns for each type of application.  The design methodology described in this book is based on propagating constraints among de...

Planar Microstrip Ring Resonators for Microwave-Based Gas Sensing: Design Aspects and Initial Transducers for Humidity and Ammonia Sensing.

Science.gov (United States)

Bogner, Andreas; Steiner, Carsten; Walter, Stefanie; Kita, Jaroslaw; Hagen, Gunter; Moos, Ralf

2017-10-24

A planar microstrip ring resonator structure on alumina was developed using the commercial FEM software COMSOL. Design parameters were evaluated, eventually leading to an optimized design of a miniaturized microwave gas sensor. The sensor was covered with a zeolite film. The device was successfully operated at around 8.5 GHz at room temperature as a humidity sensor. In the next step, an additional planar heater will be included on the reverse side of the resonator structure to allow for testing of gas-sensitive materials under sensor conditions.

Contact planarization of ensemble nanowires

Science.gov (United States)

Chia, A. C. E.; LaPierre, R. R.

2011-06-01

The viability of four organic polymers (S1808, SC200, SU8 and Cyclotene) as filling materials to achieve planarization of ensemble nanowire arrays is reported. Analysis of the porosity, surface roughness and thermal stability of each filling material was performed. Sonication was used as an effective method to remove the tops of the nanowires (NWs) to achieve complete planarization. Ensemble nanowire devices were fully fabricated and I-V measurements confirmed that Cyclotene effectively planarizes the NWs while still serving the role as an insulating layer between the top and bottom contacts. These processes and analysis can be easily implemented into future characterization and fabrication of ensemble NWs for optoelectronic device applications.

Tolerance Optimization for Mechanisms with Lubricated Joints

International Nuclear Information System (INIS)

Choi, J.-H.; Lee, S.J.; Choi, D.-H.

1998-01-01

This paper addresses an analytical approach to tolerance optimization for planar mechanisms with lubricated joints based on mechanical error analysis. The mobility method is applied to consider the lubrication effects at joints and planar mechanisms are stochastically defined by using the clearance vector model for mechanical error analysis. The uncertainties considered in the analysis are tolerances on link lengths and radial clearances and these are selected as design variables. To show the validity of the proposed method for mechanical error analysis, it is applied to two examples, and the results obtained are compared with those of Monte Carlo simulations. Based on the mechanical error analysis, tolerance optimizations are applied to the examples

Quality control on planar n-in-n pixel sensors — Recent progress of ATLAS planar pixel sensors

International Nuclear Information System (INIS)

Klingenberg, R.

2013-01-01

To extend the physics reach of the Large Hadron Collider (LHC), upgrades to the accelerator are planned which will increase the peak luminosity by a factor 5–10. To cope with the increased occupancy and radiation damage, the ATLAS experiment plans to introduce an all-silicon inner tracker with the high luminosity upgrade (HL-LHC). To investigate the suitability of pixel sensors using the proven planar technology for the upgraded tracker, the ATLAS Upgrade Planar Pixel Sensor (PPS) R and D Project was established. Main areas of research are the performance of planar pixel sensors at highest fluences, the exploration of possibilities for cost reduction to enable the instrumentation of large areas, the achievement of slim or active edges to provide low geometric inefficiencies without the need for shingling of modules and the investigation of the operation of highly irradiated sensors at low thresholds to increase the efficiency. The Insertable b-layer (IBL) is the first upgrade project within the ATLAS experiment and will employ a new detector layer consisting of silicon pixel sensors, which were improved and prototyped in the framework of the planar pixel sensor R and D project. A special focus of this paper is the status of the development and testing of planar n-in-n pixel sensors including the quality control of the on-going series production and postprocessing of sensor wafers. A high yield of produced planar sensor wafers and FE-I4 double chip sensors after first steps of post-processing including under bump metallization and dicing is observed. -- Highlights: ► Prototypes of irradiated planar n-in-n sensors have been successfully tested under laboratory conditions. ► A quality assurance programme on the series production of planar sensors for the IBL has started. ► A high yield of double chip sensors during the series production is observed which are compatible to the specifications to this detector component.

SU-F-J-11: Radiobiologically Optimized Patient Localization During Prostate External Beam Localization

Energy Technology Data Exchange (ETDEWEB)

Huang, Y; Gardner, S; Liu, C; Zhao, B; Wen, N; Brown, S; Chetty, I [Henry Ford Health System, Detroit, MI (United States)

2016-06-15

Purpose: To present a novel positioning strategy which optimizes radiation delivery with radiobiological response knowledge, and to evaluate its application during prostate external beam radiotherapy. Methods: Ten patients with low or intermediate risk prostate cancer were evaluated retrospectively in this IRB-approved study. For each patient, a VMAT plan was generated on the planning CT (PCT) to deliver 78 Gy in 39 fractions with PTV = prostate + 7 mm margin, except for 5mm in the posterior direction. Five representative pretreatment CBCT images were selected for each patient, and prostate, rectum, and bladder were delineated on all CBCT images. Each CBCT was auto-registered to the corresponding PCT. Starting from this auto-matched position (AM-position), a search for optimal treatment position was performed utilizing a score function based on radiobiological and dosimetric indices (D98-DTV, NTCP-rectum, and NTCP-bladder) for the daily target volume (DTV), rectum, and bladder. DTV was defined as prostate + 4 mm margin to account for intra-fraction motion as well as contouring variability on CBCT. We termed the optimal treatment position the radiobiologically optimized couch shift position (ROCS-position). Results: The indices, averaged over the 10 patients’ treatment plans, were (mean±SD): 77.7±0.2 Gy (D98-PTV), 12.3±2.7% (NTCP-rectum), and 53.2±11.2% (NTCP-bladder). The corresponding values calculated on all 50 CBCT images at the AM-positions were 72.9±11.3 Gy (D98-DTV), 15.8±6.4% (NTCP-rectum), and 53.0±21.1% (NTCP-bladder), respectively. In comparison, calculated on CBCT at the ROCS-positions, the indices were 77.0±2.1 Gy (D98-DTV), 12.1±5.7% (NTCP-rectum), and 60.7±16.4% (NTCP-bladder). Compared to autoregistration, ROCS-optimization recovered dose coverage to target volume and lowered the risk to rectum. Moreover, NTCPrectum for one patient remained high after ROCS-optimization and therefore could potentially benefit from adaptive planning

A highly symmetrical 10 transistor 2-read/write dual-port static random access memory bitcell design in 28 nm high-k/metal-gate planar bulk CMOS technology

Science.gov (United States)

Ishii, Yuichiro; Tanaka, Miki; Yabuuchi, Makoto; Sawada, Yohei; Tanaka, Shinji; Nii, Koji; Lu, Tien Yu; Huang, Chun Hsien; Sian Chen, Shou; Tse Kuo, Yu; Lung, Ching Cheng; Cheng, Osbert

2018-04-01

We propose a highly symmetrical 10 transistor (10T) 2-read/write (2RW) dual-port (DP) static random access memory (SRAM) bitcell in 28 nm high-k/metal-gate (HKMG) planar bulk CMOS. It replaces the conventional 8T 2RW DP SRAM bitcell without any area overhead. It significantly improves the robustness of process variations and an asymmetric issue between the true and bar bitline pairs. Measured data show that read current (I read) and read static noise margin (SNM) are respectively boosted by +20% and +15 mV by introducing the proposed bitcell with enlarged pull-down (PD) and pass-gate (PG) N-channel MOSs (NMOSs). The minimum operating voltage (V min) of the proposed 256 kbit 10T DP SRAM is 0.53 V in the TT process, 25 °C under the worst access condition with read/write disturbances, and improved by 90 mV (15%) compared with the conventional one.

Optimization of transport suppression barriers generated by externally driven Alfven waves in D-shaped, low aspect ratio tokamaks

Energy Technology Data Exchange (ETDEWEB)

Bruma, C [School of Physics and Astronomy, Tel Aviv University, 69978 Tel Aviv (Israel); Cuperman, S [School of Physics and Astronomy, Tel Aviv University, 69978 Tel Aviv (Israel); Komoshvili, K [School of Physics and Astronomy, Tel Aviv University, 69978 Tel Aviv (Israel)

2003-04-01

In an effort to optimize the internal transport barriers (ITBs) generated by externally launched mode-converted fast waves (FWs) in pre-heated spherical tokamaks (STs), we have carried out a systematic parametric investigation with respect to the rf waves and antenna characteristics; as a study case, a START-like device has been considered. Within the framework of a plasma model including both kinetic effects (collisionless Landau damping on passing electrons) and collisional damping on both trapped and passing electrons and ions, and starting with the solution of the full wave equation for a ST-plasma, we show that optimized ITBs, suitable for the stabilization of plasma turbulence (e.g. overpassing the maximum growth rate of the ITG-instability, {gamma}{sub ITG}) in STs can be generated by the aid of externally launched FW and mode-converted to kinetic Alfven waves. This result holds in spite of the limiting trapped-particles associated squeezing factor S present in the non-linear equation for E{sub r} (via the viscosity coefficient {mu}{sub {theta}}{sub i}{proportional_to}|S|{sup 3/2}, S = S(dE{sub r}/dr))

Applications for Packetized Memory Interfaces

OpenAIRE

Watson, Myles Glen

2015-01-01

The performance of the memory subsystem has a large impact on the performance of modern computer systems. Many important applications are memory bound and others are expected to become memory bound in the future. The importance of memory performance makes it imperative to understand and optimize the interactions between applications and the system architecture. Prototyping and exploring various configurations of memory systems can give important insights, but current memory interfaces are lim...

Design of planar electron gun for UHF range, CW power inductive output tube

International Nuclear Information System (INIS)

Kaushik, Meenu; Joshi, L.M.

2015-01-01

Inductive Output Tube (lOT) is an amplifier which is now-a-days in demand for scientific applications. For every vacuum tube, electron gun is an important part and in fact considered as the heart of the tube. Hence, designing of this component is very crucial for efficient operation of the device throughout its lifetime. This paper is all about the electromagnetic (EM) design of planar electron gun of 40 kV, 3.5 A beam voltage and beam current respectively, for a 100 kW CW power lOT operating in UHF range. The design considerations and basic equations involved in its design are included in the paper. The gun structure has been optimized for getting the desired beam characteristics. The simulation results including the beam profile along with the beam current are shown using two commercial codes namely TRAK and MAGIC code. Planar shape of electron beam reduces space charge forces in the beam itself and consequently beam energy spread for a given current. The magnetic focusing of planar beam is easier comparative to spherical beam hence, this structure has been adopted for this particular device design. (author)

A low-voltage flash memory cell utilizing the gate-injection program/erase method with a recessed channel structure

International Nuclear Information System (INIS)

Wu Dake; Huang Ru; Wang Pengfei; Tang Poren; Wang Yangyuan

2008-01-01

In this paper, a low-voltage recessed channel SONOS flash memory using the gate-injection program/erase method is proposed and investigated for NAND application. It is shown that the proposed flash memory can achieve 8 V lower programming voltage compared with planar flash memory, due to the effective capacitance coupling and the electric-field enhancement by combining the recessed channel structure and the gate-injection program/erase method. In addition, more than 30% larger threshold voltage window and improved short channel effects can be obtained in the proposed flash memory

Simulation of the contribution of magnetic films on planar inductors characteristics

International Nuclear Information System (INIS)

Gamet, E.; Chatelon, J.P.; Rouiller, T.; Bayard, B.; Noyel, G.; Rousseau, J.J.

2005-01-01

We propose here to use the interesting properties of magnetic thin films in order to improve planar inductors characteristics. Magnetic thin films serve as a way of confining electromagnetic field into the coil.Radio-frequency components require high-quality inductors. But at high frequencies several effects degrade the quality factor (Q) of the inductor. Our investigation deals with planar inductors, and we first try to optimize methodology of inductors design. The inductor area is kept constant (300x300μm 2 ). Characteristics of spiral inductors heavily depend on coils structures (thickness, width, number of loops, shape ...). The impact of spiral inductor parameters on the L and Q factors is studied. Q profit can reach 100% after coils parameters optimization.On the other hand, different designs with magnetic films are tested. The relative permeability (μr) of magnetic material is set to 10 and dielectric/magnetic losses are assumed to be negligeable. Thicknesses of about 10μm of magnetic material are reasonable in terms of technology and especially compatible with integration. At 2GHz, with 10μm under the coils, L and Q values have a profit of 44% and 9%, respectively compared to the non magnetic-structure.The results are based on RL model and are obtained from simulations (Ansoft HFSS) for frequencies up to 5GHz

Modified planar functions and their components

DEFF Research Database (Denmark)

Anbar Meidl, Nurdagül; Meidl, Wilfried Meidl

2017-01-01

functions in odd characteristic as a vectorial bent function. We finally point out that though these components behave somewhat different than the multivariate bent4 functions, they are bent or semibent functions shifted by a certain quadratic term, a property which they share with their multivariate......Zhou ([20]) introduced modified planar functions in order to describe (2n; 2n; 2n; 1) relative difference sets R as a graph of a function on the finite field F2n, and pointed out that projections of R are difference sets that can be described by negabent or bent4 functions, which are Boolean...... functions given in multivariate form. One of the objectives of this paper is to contribute to the understanding of these component functions of modified planar functions. Moreover, we obtain a description of modified planar functions by their components which is similar to that of the classical planar...

Low Complexity Beampattern Design in MIMO Radars Using Planar Array

KAUST Repository

Bouchoucha, Taha

2015-01-07

In multiple-input multiple-output radar systems, it is usually desirable to steer transmitted power in the region-of-interest. To do this, conventional methods optimize the waveform covariance matrix, R, for the desired beampattern, which is then used to generate actual transmitted waveforms. Both steps require constrained optimization, therefore, use iterative and expensive algorithms. In this paper, we provide a closed-form solution to design covariance matrix for the given beampattern using the planar array, which is then used to derive a novel closed-form algorithm to directly design the finite-alphabet constant-envelope (FACE) waveforms. The proposed algorithm exploits the two-dimensional fast-Fourier-transform. The performance of our proposed algorithm is compared with existing methods that are based on semi-definite quadratic programming with the advantage of a considerably reduced complexity.

A compact planar multi-broad band monopole antenna for mobile devices

Science.gov (United States)

Zhong, Xiaoqing; Yao, Bin; Zheng, Qinhong; Yang, Jikong; Cao, Xiangqi

2015-10-01

A Multiple-frequency broadband planar monopole antenna is proposed in this Paper. The antenna is stimulated and numerically optimized by HFSS13.0 (High Frequency Structure Simulator). The size of it is 39mm×22mm×1.7mm. The antenna resonates at many frequencies. The parameter S112G(DCS1800 and PCS1900), 3G(UMTS), 4G(LTE2300 and LTE2500), ISM, WLAN. It is quiet appropriate for the present ultra-thin smart phones

Systematic Development Strategy for Smart Devices Based on Shape-Memory Polymers

Directory of Open Access Journals (Sweden)

Andrés Díaz Lantada

2017-10-01

Full Text Available Shape-memory polymers are outstanding “smart” materials, which can perform important geometrical changes, when activated by several types of external stimuli, and which can be applied to several emerging engineering fields, from aerospace applications, to the development of biomedical devices. The fact that several shape-memory polymers can be structured in an additive way is an especially noteworthy advantage, as the development of advanced actuators with complex geometries for improved performance can be achieved, if adequate design and manufacturing considerations are taken into consideration. Present study presents a review of challenges and good practices, leading to a straightforward methodology (or integration of strategies, for the development of “smart” actuators based on shape-memory polymers. The combination of computer-aided design, computer-aided engineering and additive manufacturing technologies is analyzed and applied to the complete development of interesting shape-memory polymer-based actuators. Aspects such as geometrical design and optimization, development of the activation system, selection of the adequate materials and related manufacturing technologies, training of the shape-memory effect, final integration and testing are considered, as key processes of the methodology. Current trends, including the use of low-cost 3D and 4D printing, and main challenges, including process eco-efficiency and biocompatibility, are also discussed and their impact on the proposed methodology is considered.

Memory transfer optimization for a lattice Boltzmann solver on Kepler architecture nVidia GPUs

Science.gov (United States)

Mawson, Mark J.; Revell, Alistair J.

2014-10-01

The Lattice Boltzmann method (LBM) for solving fluid flow is naturally well suited to an efficient implementation for massively parallel computing, due to the prevalence of local operations in the algorithm. This paper presents and analyses the performance of a 3D lattice Boltzmann solver, optimized for third generation nVidia GPU hardware, also known as 'Kepler'. We provide a review of previous optimization strategies and analyse data read/write times for different memory types. In LBM, the time propagation step (known as streaming), involves shifting data to adjacent locations and is central to parallel performance; here we examine three approaches which make use of different hardware options. Two of which make use of 'performance enhancing' features of the GPU; shared memory and the new shuffle instruction found in Kepler based GPUs. These are compared to a standard transfer of data which relies instead on optimized storage to increase coalesced access. It is shown that the more simple approach is most efficient; since the need for large numbers of registers per thread in LBM limits the block size and thus the efficiency of these special features is reduced. Detailed results are obtained for a D3Q19 LBM solver, which is benchmarked on nVidia K5000M and K20C GPUs. In the latter case the use of a read-only data cache is explored, and peak performance of over 1036 Million Lattice Updates Per Second (MLUPS) is achieved. The appearance of a periodic bottleneck in the solver performance is also reported, believed to be hardware related; spikes in iteration-time occur with a frequency of around 11 Hz for both GPUs, independent of the size of the problem.

An in-situ measuring method for planar straightness error

Science.gov (United States)

Chen, Xi; Fu, Luhua; Yang, Tongyu; Sun, Changku; Wang, Zhong; Zhao, Yan; Liu, Changjie

2018-01-01

According to some current problems in the course of measuring the plane shape error of workpiece, an in-situ measuring method based on laser triangulation is presented in this paper. The method avoids the inefficiency of traditional methods like knife straightedge as well as the time and cost requirements of coordinate measuring machine(CMM). A laser-based measuring head is designed and installed on the spindle of a numerical control(NC) machine. The measuring head moves in the path planning to measure measuring points. The spatial coordinates of the measuring points are obtained by the combination of the laser triangulation displacement sensor and the coordinate system of the NC machine, which could make the indicators of measurement come true. The method to evaluate planar straightness error adopts particle swarm optimization(PSO). To verify the feasibility and accuracy of the measuring method, simulation experiments were implemented with a CMM. Comparing the measurement results of measuring head with the corresponding measured values obtained by composite measuring machine, it is verified that the method can realize high-precise and automatic measurement of the planar straightness error of the workpiece.

Planar channeling and quasichanneling oscillations in a bent crystal

International Nuclear Information System (INIS)

Sytov, A.I.; Guidi, V.; Bagli, E.; Bandiera, L.; Germogli, G.; Mazzolari, A.; Tikhomirov, V.V.

2016-01-01

Particles passing through a crystal under planar channeling are captured by a continuous potential and experience transverse oscillations in their motion. As channeled particles approach the atomic planes, they are likely to be dechanneled. This effect is being used in ion-beam analysis with MeV energy. We study this effect in a bent crystal for positive and negative particles within a wide range of energies in sight of application of such crystals at accelerators. We look for the conditions for the observation or not of channeling oscillations in the deflection angle distribution in experiments where the beam passes through the bent crystal. Indeed a new kind of oscillations in the deflection angle distribution, strictly related to the motion of over-barrier particles, i.e. quasichanneled particles, is predicted. Such oscillations, named planar quasichanneling oscillations, possess a different nature than channeling oscillations. Through computer simulation, we study this effect and provided a theoretical interpretation for them. We show that channeling oscillations can be observed only for positive particles while quasichanneling oscillations can exist for particles with either sign. The conditions for experimental observation of channeling and quasichanneling oscillations at existing accelerators with available crystal are found and optimized. (orig.)

Planar channeling and quasichanneling oscillations in a bent crystal

Energy Technology Data Exchange (ETDEWEB)

Sytov, A.I. [Universita di Ferrara, Dipartimento di Fisica e Scienze della Terra, Ferrara (Italy); Belarusian State University, Research Institute for Nuclear Problems, Minsk (Belarus); INFN, Ferrara (Italy); Guidi, V.; Bagli, E.; Bandiera, L.; Germogli, G.; Mazzolari, A. [Universita di Ferrara, Dipartimento di Fisica e Scienze della Terra, Ferrara (Italy); INFN, Ferrara (Italy); Tikhomirov, V.V. [Belarusian State University, Research Institute for Nuclear Problems, Minsk (Belarus); INFN, Ferrara (Italy)

2016-02-15

Particles passing through a crystal under planar channeling are captured by a continuous potential and experience transverse oscillations in their motion. As channeled particles approach the atomic planes, they are likely to be dechanneled. This effect is being used in ion-beam analysis with MeV energy. We study this effect in a bent crystal for positive and negative particles within a wide range of energies in sight of application of such crystals at accelerators. We look for the conditions for the observation or not of channeling oscillations in the deflection angle distribution in experiments where the beam passes through the bent crystal. Indeed a new kind of oscillations in the deflection angle distribution, strictly related to the motion of over-barrier particles, i.e. quasichanneled particles, is predicted. Such oscillations, named planar quasichanneling oscillations, possess a different nature than channeling oscillations. Through computer simulation, we study this effect and provided a theoretical interpretation for them. We show that channeling oscillations can be observed only for positive particles while quasichanneling oscillations can exist for particles with either sign. The conditions for experimental observation of channeling and quasichanneling oscillations at existing accelerators with available crystal are found and optimized. (orig.)

Language and Verbal Memory in Individuals with a History of Autism Spectrum Disorders Who Have Achieved Optimal Outcomes

Science.gov (United States)

Tyson, Katherine; Kelley, Elizabeth; Fein, Deborah; Orinstein, Alyssa; Troyb, Eva; Barton, Marianne; Eigsti, Inge-Marie; Naigles, Letitia; Schultz, Robert T.; Stevens, Michael; Helt, Molly; Rosenthal, Michael

2014-01-01

Some individuals who lose their autism spectrum disorder diagnosis may continue to display subtle weaknesses in language. We examined language and verbal memory in 44 individuals with high-functioning autism (HFA), 34 individuals with "optimal outcomes" (OO) and 34 individuals with typical development (TD). The OO group scored in the…

Orientifold Planar Equivalence: The Chiral Condensate

DEFF Research Database (Denmark)

Armoni, Adi; Lucini, Biagio; Patella, Agostino

2008-01-01

The recently introduced orientifold planar equivalence is a promising tool for solving non-perturbative problems in QCD. One of the predictions of orientifold planar equivalence is that the chiral condensates of a theory with $N_f$ flavours of Dirac fermions in the symmetric (or antisymmetric...

Overview of Planar Magnetic Technology — Fundamental Properties

DEFF Research Database (Denmark)

Ouyang, Ziwei; Andersen, Michael A. E.

2014-01-01

The momentum towards high efficiency, high frequency, and high power density in power supplies limits wide use of conventional wire-wound magnetic components. This article gives an overview of planar magnetic technologies with respect to the development of modern power electronics. The major...... advantages and disadvantages in the use of planar magnetics for high frequency power converters are covered, and publications on planar magnetics are reviewed. A detailed survey of winding conduction loss, leakage inductance and winding capacitance for planar magnetics is presented so power electronics...

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.

Cognitive rehabilitation of episodic memory disorders: from theory to practice

OpenAIRE

Radek Ptak; Radek Ptak; Martial Van Der Linden; Armin Schnider; Armin Schnider

2010-01-01

Memory disorders are among the most frequent and most debilitating cognitive impairments following acquired brain damage. Cognitive remediation strategies attempt to restore lost memory capacity, provide compensatory techniques or teach the use of external memory aids. Memory rehabilitation has strongly been influenced by memory theory, and the interaction between both has stimulated the development of techniques such as spaced retrieval, vanishing cues or errorless learning. These techniques...

Cognitive Rehabilitation of Episodic Memory Disorders: From Theory to Practice

OpenAIRE

Ptak, Radek; der Linden, Martial Van; Schnider, Armin

2010-01-01

Memory disorders are among the most frequent and most debilitating cognitive impairments following acquired brain damage. Cognitive remediation strategies attempt to restore lost memory capacity, provide compensatory techniques or teach the use of external memory aids. Memory rehabilitation has strongly been influenced by memory theory, and the interaction between both has stimulated the development of techniques such as spaced retrieval, vanishing cues or errorless learning. These techniques...

About sleep's role in memory.

Science.gov (United States)

Rasch, Björn; Born, Jan

2013-04-01

Over more than a century of research has established the fact that sleep benefits the retention of memory. In this review we aim to comprehensively cover the field of "sleep and memory" research by providing a historical perspective on concepts and a discussion of more recent key findings. Whereas initial theories posed a passive role for sleep enhancing memories by protecting them from interfering stimuli, current theories highlight an active role for sleep in which memories undergo a process of system consolidation during sleep. Whereas older research concentrated on the role of rapid-eye-movement (REM) sleep, recent work has revealed the importance of slow-wave sleep (SWS) for memory consolidation and also enlightened some of the underlying electrophysiological, neurochemical, and genetic mechanisms, as well as developmental aspects in these processes. Specifically, newer findings characterize sleep as a brain state optimizing memory consolidation, in opposition to the waking brain being optimized for encoding of memories. Consolidation originates from reactivation of recently encoded neuronal memory representations, which occur during SWS and transform respective representations for integration into long-term memory. Ensuing REM sleep may stabilize transformed memories. While elaborated with respect to hippocampus-dependent memories, the concept of an active redistribution of memory representations from networks serving as temporary store into long-term stores might hold also for non-hippocampus-dependent memory, and even for nonneuronal, i.e., immunological memories, giving rise to the idea that the offline consolidation of memory during sleep represents a principle of long-term memory formation established in quite different physiological systems.

Some remarks on non-planar Feynman diagrams

International Nuclear Information System (INIS)

Bielas, Krzysztof; Dubovyk, Ievgen; Gluza, Janusz

2013-12-01

Two criteria for planarity of a Feynman diagram upon its propagators (momentum ows) are presented. Instructive Mathematica programs that solve the problem and examples are provided. A simple geometric argument is used to show that while one can planarize non-planar graphs by embedding them on higher-genus surfaces (in the example it is a torus), there is still a problem with defining appropriate dual variables since the corresponding faces of the graph are absorbed by torus generators.

Some remarks on non-planar Feynman diagrams

Energy Technology Data Exchange (ETDEWEB)

Bielas, Krzysztof; Dubovyk, Ievgen; Gluza, Janusz [Silesia Univ., Katowice (Poland). Inst. of Physics; Riemann, Tord [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

2013-12-15

Two criteria for planarity of a Feynman diagram upon its propagators (momentum ows) are presented. Instructive Mathematica programs that solve the problem and examples are provided. A simple geometric argument is used to show that while one can planarize non-planar graphs by embedding them on higher-genus surfaces (in the example it is a torus), there is still a problem with defining appropriate dual variables since the corresponding faces of the graph are absorbed by torus generators.

A Memory Hierarchy Model Based on Data Reuse for Full-Search Motion Estimation on High-Definition Digital Videos

Directory of Open Access Journals (Sweden)

Alba Sandyra Bezerra Lopes

2012-01-01

Full Text Available The motion estimation is the most complex module in a video encoder requiring a high processing throughput and high memory bandwidth, mainly when the focus is high-definition videos. The throughput problem can be solved increasing the parallelism in the internal operations. The external memory bandwidth may be reduced using a memory hierarchy. This work presents a memory hierarchy model for a full-search motion estimation core. The proposed memory hierarchy model is based on a data reuse scheme considering the full search algorithm features. The proposed memory hierarchy expressively reduces the external memory bandwidth required for the motion estimation process, and it provides a very high data throughput for the ME core. This throughput is necessary to achieve real time when processing high-definition videos. When considering the worst bandwidth scenario, this memory hierarchy is able to reduce the external memory bandwidth in 578 times. A case study for the proposed hierarchy, using 32×32 search window and 8×8 block size, was implemented and prototyped on a Virtex 4 FPGA. The results show that it is possible to reach 38 frames per second when processing full HD frames (1920×1080 pixels using nearly 299 Mbytes per second of external memory bandwidth.

Coating material innovation in conjunction with optimized deposition technologies

International Nuclear Information System (INIS)

Stolze, M.; Leitner, K.

2009-01-01

Concentrating on physical vapour deposition methods several examples of recently developed coating materials for optical applications were studied for film deposition with optimized coating technologies: mixed evaporation materials for ion assisted deposition with modern plasma ion sources, planar metal and oxide sputter targets for Direct Current (DC) and Mid-Frequency (MF) pulsed sputter deposition and planar and rotatable sputter targets of transparent conductive oxides (TCO) for large-area sputter deposition. Films from specially designed titania based mixed evaporation materials deposited with new plasma ion sources and possible operation with pure oxygen showed extended ranges of the ratio between refractive index and structural film stress, hence there is an increased potential for the reduction of the total coating stress in High-Low alternating stacks and for coating plastics. DC and MF-pulsed sputtering of niobium metal and suboxide targets for optical coatings yielded essential benefits of the suboxide targets in a range of practical coating conditions (for absent in-situ post-oxidation ability): higher refractive index and deposition rate, better reproducibility and easier process control, and the potential for co-deposition of several targets. Technological progress in the manufacture of rotatable indium tin oxide (ITO) targets with regard to higher wall-thickness and density was shown to be reflected in higher material stock and coater up-time, economical deposition rates and stable process behaviour. Both for the rotatable ITO targets and higher-dense aluminum-doped zinc oxide (AZO) planar targets values of film transmittance and resistivity were in the range of the best values industrially achieved for films from the respective planar targets. The results for the rotatable ITO and planar AZO targets point to equally optimized process and film properties for the optimized rotatable AZO targets currently in testing

Algorithm for Optimizing Bipolar Interconnection Weights with Applications in Associative Memories and Multitarget Classification

Science.gov (United States)

Chang, Shengjiang; Wong, Kwok-Wo; Zhang, Wenwei; Zhang, Yanxin

1999-08-01

An algorithm for optimizing a bipolar interconnection weight matrix with the Hopfield network is proposed. The effectiveness of this algorithm is demonstrated by computer simulation and optical implementation. In the optical implementation of the neural network the interconnection weights are biased to yield a nonnegative weight matrix. Moreover, a threshold subchannel is added so that the system can realize, in real time, the bipolar weighted summation in a single channel. Preliminary experimental results obtained from the applications in associative memories and multitarget classification with rotation invariance are shown.

External force back-projective composition and globally deformable optimization for 3-D coronary artery reconstruction

International Nuclear Information System (INIS)

Yang, Jian; Cong, Weijian; Fan, Jingfan; Liu, Yue; Wang, Yongtian; Chen, Yang

2014-01-01

The clinical value of the 3D reconstruction of a coronary artery is important for the diagnosis and intervention of cardiovascular diseases. This work proposes a method based on a deformable model for reconstructing coronary arteries from two monoplane angiographic images acquired from different angles. First, an external force back-projective composition model is developed to determine the external force, for which the force distributions in different views are back-projected to the 3D space and composited in the same coordinate system based on the perspective projection principle of x-ray imaging. The elasticity and bending forces are composited as an internal force to maintain the smoothness of the deformable curve. Second, the deformable curve evolves rapidly toward the true vascular centerlines in 3D space and angiographic images under the combination of internal and external forces. Third, densely matched correspondence among vessel centerlines is constructed using a curve alignment method. The bundle adjustment method is then utilized for the global optimization of the projection parameters and the 3D structures. The proposed method is validated on phantom data and routine angiographic images with consideration for space and re-projection image errors. Experimental results demonstrate the effectiveness and robustness of the proposed method for the reconstruction of coronary arteries from two monoplane angiographic images. The proposed method can achieve a mean space error of 0.564 mm and a mean re-projection error of 0.349 mm. (paper)

Planarity certification of ATLAS Micromegas detector panels

Energy Technology Data Exchange (ETDEWEB)

Mueller, Ralph; Biebel, Otmar; Bortfeldt, Jonathan; Flierl, Bernhard; Hertenberger, Ralf; Loesel, Philipp; Herrmann, Maximilian [LMU Muenchen (Germany); Zibell, Andre [JMU Wuerzburg (Germany)

2016-07-01

During the second long LHC shutdown, 2019/20, the precision tracking detectors of the ATLAS muon spectrometer in the inner end caps will be replaced using Micromegas, a planar gas-detector technology. Modules of 2 m{sup 2} area are built in quadruplets from five precisely planar sandwich panels that define the anodes and the cathodes of the four active detector planes. A panel is composed of three consecutive layers FR4 - aluminum honeycomb - FR4. Single plane spatial particle resolution below 100 μm is achievable when the deviations from planarity of the strip-anodes do not exceed 80 μm RMS over the whole active area and the parallelism of the readout strips is within 30 μm. In order to measure the dimensional accuracy of each panel, laser distance sensors combined with a coordinate measurement system have been investigated. The sensor requirements to measure the planarity of the panels are a resolution of 0.3 μm and a beam spot diameter of ∼20 μm, well below 100 μ m the size of the smallest structures. We report on achieved planarities of the panels and the performance of the laser sensor system. A panel with an RMS better than 30 μm was build and the evolution of its planarity due to humidity and temperature effects is shown.

About Sleep's Role in Memory

Science.gov (United States)

2013-01-01

Over more than a century of research has established the fact that sleep benefits the retention of memory. In this review we aim to comprehensively cover the field of “sleep and memory” research by providing a historical perspective on concepts and a discussion of more recent key findings. Whereas initial theories posed a passive role for sleep enhancing memories by protecting them from interfering stimuli, current theories highlight an active role for sleep in which memories undergo a process of system consolidation during sleep. Whereas older research concentrated on the role of rapid-eye-movement (REM) sleep, recent work has revealed the importance of slow-wave sleep (SWS) for memory consolidation and also enlightened some of the underlying electrophysiological, neurochemical, and genetic mechanisms, as well as developmental aspects in these processes. Specifically, newer findings characterize sleep as a brain state optimizing memory consolidation, in opposition to the waking brain being optimized for encoding of memories. Consolidation originates from reactivation of recently encoded neuronal memory representations, which occur during SWS and transform respective representations for integration into long-term memory. Ensuing REM sleep may stabilize transformed memories. While elaborated with respect to hippocampus-dependent memories, the concept of an active redistribution of memory representations from networks serving as temporary store into long-term stores might hold also for non-hippocampus-dependent memory, and even for nonneuronal, i.e., immunological memories, giving rise to the idea that the offline consolidation of memory during sleep represents a principle of long-term memory formation established in quite different physiological systems. PMID:23589831

Transactive memory in organizational groups: the effects of content, consensus, specialization, and accuracy on group performance.

Science.gov (United States)

Austin, John R

2003-10-01

Previous research on transactive memory has found a positive relationship between transactive memory system development and group performance in single project laboratory and ad hoc groups. Closely related research on shared mental models and expertise recognition supports these findings. In this study, the author examined the relationship between transactive memory systems and performance in mature, continuing groups. A group's transactive memory system, measured as a combination of knowledge stock, knowledge specialization, transactive memory consensus, and transactive memory accuracy, is positively related to group goal performance, external group evaluations, and internal group evaluations. The positive relationship with group performance was found to hold for both task and external relationship transactive memory systems.

Age differences in perceptions of memory strategy effectiveness for recent and remote memory.

Science.gov (United States)

Lineweaver, Tara T; Horhota, Michelle; Crumley, Jessica; Geanon, Catherine T; Juett, Jacqueline J

2018-03-01

We examined whether young and older adults hold different beliefs about the effectiveness of memory strategies for specific types of memory tasks and whether memory strategies are perceived to be differentially effective for young, middle-aged, and older targets. Participants rated the effectiveness of five memory strategies for 10 memory tasks at three target ages (20, 50, and 80 years old). Older adults did not strongly differentiate strategy effectiveness, viewing most strategies as similarly effective across memory tasks. Young adults held strategy-specific beliefs, endorsing external aids and physical health as more effective than a positive attitude or internal strategies, without substantial differentiation based on task. We also found differences in anticipated strategy effectiveness for targets of different ages. Older adults described cognitive and physical health strategies as more effective for older than middle-aged targets, whereas young adults expected these strategies to be equally effective for middle-aged and older target adults.

Autobiographical thinking interferes with episodic memory consolidation.

Directory of Open Access Journals (Sweden)

Michael Craig

Full Text Available New episodic memories are retained better if learning is followed by a few minutes of wakeful rest than by the encoding of novel external information. Novel encoding is said to interfere with the consolidation of recently acquired episodic memories. Here we report four experiments in which we examined whether autobiographical thinking, i.e. an 'internal' memory activity, also interferes with episodic memory consolidation. Participants were presented with three wordlists consisting of common nouns; one list was followed by wakeful rest, one by novel picture encoding and one by autobiographical retrieval/future imagination, cued by concrete sounds. Both novel encoding and autobiographical retrieval/future imagination lowered wordlist retention significantly. Follow-up experiments demonstrated that the interference by our cued autobiographical retrieval/future imagination delay condition could not be accounted for by the sound cues alone or by executive retrieval processes. Moreover, our results demonstrated evidence of a temporal gradient of interference across experiments. Thus, we propose that rich autobiographical retrieval/future imagination hampers the consolidation of recently acquired episodic memories and that such interference is particularly likely in the presence of external concrete cues.

Finding a pareto-optimal solution for multi-region models subject to capital trade and spillover externalities

Energy Technology Data Exchange (ETDEWEB)

Leimbach, Marian [Potsdam-Institut fuer Klimafolgenforschung e.V., Potsdam (Germany); Eisenack, Klaus [Oldenburg Univ. (Germany). Dept. of Economics and Statistics

2008-11-15

In this paper we present an algorithm that deals with trade interactions within a multi-region model. In contrast to traditional approaches this algorithm is able to handle spillover externalities. Technological spillovers are expected to foster the diffusion of new technologies, which helps to lower the cost of climate change mitigation. We focus on technological spillovers which are due to capital trade. The algorithm of finding a pareto-optimal solution in an intertemporal framework is embedded in a decomposed optimization process. The paper analyzes convergence and equilibrium properties of this algorithm. In the final part of the paper, we apply the algorithm to investigate possible impacts of technological spillovers. While benefits of technological spillovers are significant for the capital-importing region, benefits for the capital-exporting region depend on the type of regional disparities and the resulting specialization and terms-of-trade effects. (orig.)

Optimal operation management of fuel cell/wind/photovoltaic power sources connected to distribution networks

Science.gov (United States)

Niknam, Taher; Kavousifard, Abdollah; Tabatabaei, Sajad; Aghaei, Jamshid

2011-10-01

In this paper a new multiobjective modified honey bee mating optimization (MHBMO) algorithm is presented to investigate the distribution feeder reconfiguration (DFR) problem considering renewable energy sources (RESs) (photovoltaics, fuel cell and wind energy) connected to the distribution network. The objective functions of the problem to be minimized are the electrical active power losses, the voltage deviations, the total electrical energy costs and the total emissions of RESs and substations. During the optimization process, the proposed algorithm finds a set of non-dominated (Pareto) optimal solutions which are stored in an external memory called repository. Since the objective functions investigated are not the same, a fuzzy clustering algorithm is utilized to handle the size of the repository in the specified limits. Moreover, a fuzzy-based decision maker is adopted to select the 'best' compromised solution among the non-dominated optimal solutions of multiobjective optimization problem. In order to see the feasibility and effectiveness of the proposed algorithm, two standard distribution test systems are used as case studies.

Investigation of balancing problem for a planar mechanism using genetic algorithm

International Nuclear Information System (INIS)

Erkaya, Selcuk

2013-01-01

In this study, optimal balancing of a planar articulated mechanism is investigated to minimize the shaking force and moment fluctuations. Balancing of a four-bar mechanism is formulated as an optimization problem. On the other hand, an objective function based on the sub-components of shaking force and moment is constituted, and design variables consisting of kinematic and dynamic parameters are defined. Genetic algorithm is used to solve the optimization problem under the appropriate constraints. By using commercial simulation software, optimized values of design variables are also tested to evaluate the effectiveness of the proposed optimization process. This work provides a practical method for reducing the shaking force and moment fluctuations. The results show that both the structure of objective function and particularly the selection of weighting factors have a crucial role to obtain the optimum values of design parameters. By adjusting the value of weighting factor according to the relative sensitivity of the related term, there is a certain decrease at the shaking force and moment fluctuations. Moreover, these arrangements also decrease the initiative of mechanism designer on choosing the values of weighting factors.

The Benefit of Attention-to-Memory Depends on the Interplay of Memory Capacity and Memory Load

Science.gov (United States)

Lim, Sung-Joo; Wöstmann, Malte; Geweke, Frederik; Obleser, Jonas

2018-01-01

Humans can be cued to attend to an item in memory, which facilitates and enhances the perceptual precision in recalling this item. Here, we demonstrate that this facilitating effect of attention-to-memory hinges on the overall degree of memory load. The benefit an individual draws from attention-to-memory depends on her overall working memory performance, measured as sensitivity (d′) in a retroactive cue (retro-cue) pitch discrimination task. While listeners maintained 2, 4, or 6 auditory syllables in memory, we provided valid or neutral retro-cues to direct listeners’ attention to one, to-be-probed syllable in memory. Participants’ overall memory performance (i.e., perceptual sensitivity d′) was relatively unaffected by the presence of valid retro-cues across memory loads. However, a more fine-grained analysis using psychophysical modeling shows that valid retro-cues elicited faster pitch-change judgments and improved perceptual precision. Importantly, as memory load increased, listeners’ overall working memory performance correlated with inter-individual differences in the degree to which precision improved (r = 0.39, p = 0.029). Under high load, individuals with low working memory profited least from attention-to-memory. Our results demonstrate that retrospective attention enhances perceptual precision of attended items in memory but listeners’ optimal use of informative cues depends on their overall memory abilities. PMID:29520246

The Benefit of Attention-to-Memory Depends on the Interplay of Memory Capacity and Memory Load

Directory of Open Access Journals (Sweden)

Sung-Joo Lim

2018-02-01

Full Text Available Humans can be cued to attend to an item in memory, which facilitates and enhances the perceptual precision in recalling this item. Here, we demonstrate that this facilitating effect of attention-to-memory hinges on the overall degree of memory load. The benefit an individual draws from attention-to-memory depends on her overall working memory performance, measured as sensitivity (d′ in a retroactive cue (retro-cue pitch discrimination task. While listeners maintained 2, 4, or 6 auditory syllables in memory, we provided valid or neutral retro-cues to direct listeners’ attention to one, to-be-probed syllable in memory. Participants’ overall memory performance (i.e., perceptual sensitivity d′ was relatively unaffected by the presence of valid retro-cues across memory loads. However, a more fine-grained analysis using psychophysical modeling shows that valid retro-cues elicited faster pitch-change judgments and improved perceptual precision. Importantly, as memory load increased, listeners’ overall working memory performance correlated with inter-individual differences in the degree to which precision improved (r = 0.39, p = 0.029. Under high load, individuals with low working memory profited least from attention-to-memory. Our results demonstrate that retrospective attention enhances perceptual precision of attended items in memory but listeners’ optimal use of informative cues depends on their overall memory abilities.

ytterbium- & erbium-doped silica for planar waveguide lasers & amplifiers

DEFF Research Database (Denmark)

Dyndgaard, Morten Glarborg

2001-01-01

The purpose of this work was to demonstrate ytterbium doped planar components and investigate the possibilities of making erbium/ytterbium codoped planar waveguides in germano-silica glass. Furthermore, tools for modelling lasers and erbium/ytterbium doped amplifiers. The planar waveguides were...

The Design of Polymer Planar Optical Triplexer with MMI Filter and Directional Coupler

Directory of Open Access Journals (Sweden)

V. Jerabek

2013-12-01

Full Text Available Optical bidirectional WDM transceiver is a key component of the Passive Optical Network of the Fiber to the Home topology. Essential parts of such transceivers are filters that combine multiplexing and demultiplexing function of optical signal (triplexing filters. In this paper we report about a design of a new planar optical multi-wavelength selective system triplexing filter, which combines a multimode interference filter with directional coupler based on the epoxy polymer SU-8 on Si/SiO2 substrate. The optical triplexing filter was designed using the Beam Propagation Method. The aim of this project was to optimize the triplexing filter optical parameters and to minimize the planar optical wavelength selective system dimensions. The multimode interference filter was used for separation of downstream optical signal in designed optoelectronic integrated WDM transceiver. The directional coupler was used for adding of upstream optical signal.

Planar Poincare chart - A planar graphic representation of the state of light polarization

Science.gov (United States)

Tedjojuwono, Ken K.; Hunter, William W., Jr.; Ocheltree, Stewart L.

1989-01-01

The planar Poincare chart, which represents the complete planar equivalence of the Poincare sphere, is proposed. The four sets of basic lines are drawn on two separate charts for the generalization and convenience of reading the scale. The chart indicates the rotation of the principal axes of linear birefringent material. The relationships between parameters of the two charts are given as 2xi-2phi (orientation angle of the major axis-ellipticity angle) pair and 2alpha-delta (angle of amplitude ratio-phase difference angle) pair. The results are useful for designing and analyzing polarization properties of optical components with birefringent properties.

High-performance inverted planar heterojunction perovskite solar cells based on a solution-processed CuOx hole transport layer.

Science.gov (United States)

Sun, Weihai; Li, Yunlong; Ye, Senyun; Rao, Haixia; Yan, Weibo; Peng, Haitao; Li, Yu; Liu, Zhiwei; Wang, Shufeng; Chen, Zhijian; Xiao, Lixin; Bian, Zuqiang; Huang, Chunhui

2016-05-19

During the past several years, methylammonium lead halide perovskites have been widely investigated as light absorbers for thin-film photovoltaic cells. Among the various device architectures, the inverted planar heterojunction perovskite solar cells have attracted special attention for their relatively simple fabrication and high efficiencies. Although promising efficiencies have been obtained in the inverted planar geometry based on poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) sulfonic acid ( PSS) as the hole transport material (HTM), the hydrophilicity of the PSS is a critical factor for long-term stability. In this paper, a CuOx hole transport layer from a facile solution-processed method was introduced into the inverted planar heterojunction perovskite solar cells. After the optimization of the devices, a champion PCE of 17.1% was obtained with an open circuit voltage (Voc) of 0.99 V, a short-circuit current (Jsc) of 23.2 mA cm(-2) and a fill factor (FF) of 74.4%. Furthermore, the unencapsulated device cooperating with the CuOx film exhibited superior performance in the stability test, compared to the device involving the PSS layer, indicating that CuOx could be a promising HTM for replacing PSS in inverted planar heterojunction perovskite solar cells.

Adaptive proportional–integral–derivative tuning sliding mode control for a shape memory alloy actuator

International Nuclear Information System (INIS)

Tai, Nguyen Trong; Ahn, Kyoung Kwan

2011-01-01

In this paper, a novel adaptive sliding mode control with a proportional–integral–derivative (PID) tuning method is proposed to control a shape memory alloy (SMA) actuator. The goal of the controller is to achieve system robustness against the SMA hysteresis phenomenon, system uncertainties and external disturbances. In the controller, the PID controller is employed to approximate the sliding mode equivalent control along the direction that makes the sliding mode asymptotically stable. Due to the system nonlinearity, the PID control gain parameters are systematically computed online according to the adaptive law. To improve the transient performance, the initial PID gain parameters are optimized by the particle swarm optimization (PSO) method. Simulation and experimental results demonstrate that the controller performs well for the desired trajectory tracking, and the hysteresis phenomenon is compensated for completely. The control results are also compared with the optimized PID controller

Robust nonlinear PID-like fuzzy logic control of a planar parallel (2PRP-PPR) manipulator.

Science.gov (United States)

Londhe, P S; Singh, Yogesh; Santhakumar, M; Patre, B M; Waghmare, L M

2016-07-01

In this paper, a robust nonlinear proportional-integral-derivative (PID)-like fuzzy control scheme is presented and applied to complex trajectory tracking control of a 2PRP-PPR (P-prismatic, R-revolute) planar parallel manipulator (motion platform) with three degrees-of-freedom (DOF) in the presence of parameter uncertainties and external disturbances. The proposed control law consists of mainly two parts: first part uses a feed forward term to enhance the control activity and estimated perturbed term to compensate for the unknown effects namely external disturbances and unmodeled dynamics, and the second part uses a PID-like fuzzy logic control as a feedback portion to enhance the overall closed-loop stability of the system. Experimental results are presented to show the effectiveness of the proposed control scheme. Copyright © 2016 ISA. Published by Elsevier Ltd. All rights reserved.

Development and optimization of dispersible tablet of Bacopa monnieri with improved functionality for memory enhancement

Directory of Open Access Journals (Sweden)

Vaishali Tejas Thakkar

2017-01-01

Full Text Available Introduction: The Bacopa monnieri is traditional Ayurvedic medicine, and reported for memory-enhancing effects. The Bacoside is poorly soluble, bitter in taste and responsible for the memory enhancement action. Memory enhancer is commonly prescribed for children or elder people. Objective: Poor solubility, patient compliance and bitterness were a major driving force to develop taste masked β-cyclodextrin complex and dispersible tablets. Materials and Methods: The inclusion complex of Bacopa monnieri and β-cyclodextrin was prepared in different molar ratios of Bacopa monnieri by Co-precipitation method. Phase solubility study was conducted to evaluate the effect of β-cyclodextrin on aqueous solubility of Bacoside A. The characterization was determined by Fourier transformation infrared spectroscopy (FTIR,Differential scanning calorimetry (DSC and X-ray diffraction study (XRD.Crospovidone and croscarmallose sodium were used as super disintigrant.The 32 full factorial design was adopted to investigate the influence of two superdisintegrants on the wetting time and disntegration time of the tablets. Conclusion: The result revels that molar ratio (1:4 of inclusion complex enhance 3-fold solubility. Full factorial design was successfully employed for the optimization of dispersible tablet of B. monnieri . The short-term accelerated stability study confirmed that high stability of B. monnieri in inclusion complex.

Characterization of thermoset and thermoplastic polyurethane pads, and molded and non-optimized machined grooving methods for oxide chemical mechanical planarization applications

International Nuclear Information System (INIS)

Sampurno, Yasa; Borucki, Leonard; Zhuang, Yun; Misra, Sudhanshu; Holland, Karey; Boning, Duane; Philipossian, Ara

2009-01-01

This paper systematically studies the effect of pad material, grooving method and grooving pattern on interlayer dielectric chemical mechanical planarization. The tested polishing pads consist of thermoplastic and thermoset polyurethanes synthesized using two different processes. Grooves created using a molding technique are compared with grooves formed by mechanical cutting. The concentric groove design is also compared with the logarithmic positive spiral positive grooving design. Experimental data collected include removal rate, coefficient of friction, shear force variance, pad temperature and dynamic mechanical analyzer measurements. Scanning electron microscope images are used to correlate grooving methods with coefficient of friction and shear force variance measurements. Results show that all of the pads polish wafers in boundary lubrication mode with unique friction coefficient, shear force variance and pad temperature characteristics. Simulations using a two-step removal rate mechanism are performed to estimate the chemical and mechanical rate constants. The analysis indicates that the thermoplastic pad is more mechanically controlled than the thermoset pad and that molded grooving induces a more mechanically controlled process than non-optimized machined grooving

A pilot study of planar coil based magnetic stimulation using acute hippocampal slice in mice.

Science.gov (United States)

Park, H J; Kang, H K; Wang, M; Jo, J; Chung, E; Kim, S

2017-07-01

Micromagnetic stimulation using small-sized implantable coils has recently been studied. The main advantage of this method is that it can provide sustainable stimulation performance even if a fibrotic encapsulation layer is formed around the implanted coil by inflammation response, because indirectly induced currents are used to induce neural responses. In previous research, we optimized the geometrical and control parameters used in implantable magnetic stimulation. Based on those results, we fabricated the planar coil and studied the LTP effect in the hippocampal slice by two different magnetic stimulation protocols using the quadripulse stimulation (QPS) pattern. We found that direct magnetic stimulation (DMS) induced insignificant LTP effect and priming magnetic stimulation (PMS) occluded LTP effect after tetanic stimulation, when QPS patterned magnetic stimulation with 1 A current pulse was applied to the planar coil.

Flat panel planar optic display

Energy Technology Data Exchange (ETDEWEB)

Veligdan, J.T. [Brookhaven National Lab., Upton, NY (United States). Dept. of Advanced Technology

1994-11-01

A prototype 10 inch flat panel Planar Optic Display, (POD), screen has been constructed and tested. This display screen is comprised of hundreds of planar optic class sheets bonded together with a cladding layer between each sheet where each glass sheet represents a vertical line of resolution. The display is 9 inches wide by 5 inches high and approximately 1 inch thick. A 3 milliwatt HeNe laser is used as the illumination source and a vector scanning technique is employed.

Control of crack pattern using memory effect of paste

International Nuclear Information System (INIS)

Nakahara, Akio; Shinohara, Yuu; Matsuo, Yousuke

2011-01-01

A densely packed colloidal suspension, called as a paste, remembers the direction of external mechanical fields, such as flow and vibration. When the pastes are dried, memories in pastes are visualized as macroscopically anisotropic crack patterns, such as lamellar, radial, ring and spiral. Here, we experimentally investigate how pastes remember such experiences by using paste with different size distribution of colloidal particles. We find that a paste with smaller particles have a better memory, in the sense it remembers external mechanical fields at smaller solid volume fraction, which implies that interparticle forces between colloidal particles play an important role in memory effects, causing a quantitative change in the phase diagram for the same material. This result supports the hypothesis that memories in pastes are maintained as microscopically anisotropic network structure of colloidal particles, connected via interparticle forces between colloidal particles, such as van der Waals interaction.

Planar Algebra of the Subgroup-Subfactor

Indian Academy of Sciences (India)

The crucial step in this identification is an exhibition of a model for the basic construction tower, and thereafter of the standard invariant of R ⋊ H ⊂ R ⋊ G in terms of operator matrices. We also obtain an identification between the planar algebra of the fixed algebra subfactor R G ⊂ R H and the -invariant planar subalgebra ...

On the Synthesis of Sub-arrayed Planar Array Antennas for Tracking Radar Applications

OpenAIRE

Manica, Luca; Rocca, Paolo; Massa, Andrea

2011-01-01

The synthesis of compromise sum and difference patterns of large planar arrays is addressed in this letter by means of a suitable implementation of the Contiguous Partition Method (CPM). By exploiting some properties of the solution space, the generation of compromise sum-difference patterns is recast as the searching of the optimal path in a graph that codes the admissible solution space. Some numerical experiments are provided in order to assess the effectiveness of the proposed method. (c)...

Use of explicit memory cues following parietal lobe lesions.

Science.gov (United States)

Dobbins, Ian G; Jaeger, Antonio; Studer, Bettina; Simons, Jon S

2012-11-01

The putative role of the lateral parietal lobe in episodic memory has recently become a topic of considerable debate, owing primarily to its consistent activation for studied materials during functional magnetic resonance imaging studies of recognition. Here we examined the performance of patients with parietal lobe lesions using an explicit memory cueing task in which probabilistic cues ("Likely Old" or "Likely New"; 75% validity) preceded the majority of verbal recognition memory probes. Without cues, patients and control participants did not differ in accuracy. However, group differences emerged during the "Likely New" cue condition with controls responding more accurately than parietal patients when these cues were valid (preceding new materials) and trending towards less accuracy when these cues were invalid (preceding old materials). Both effects suggest insufficient integration of external cues into memory judgments on the part of the parietal patients whose cued performance largely resembled performance in the complete absence of cues. Comparison of the parietal patients to a patient group with frontal lobe lesions suggested the pattern was specific to parietal and adjacent area lesions. Overall, the data indicate that parietal lobe patients fail to appropriately incorporate external cues of novelty into recognition attributions. This finding supports a role for the lateral parietal lobe in the adaptive biasing of memory judgments through the integration of external cues and internal memory evidence. We outline the importance of such adaptive biasing through consideration of basic signal detection predictions regarding maximum possible accuracy with and without informative environmental cues. Copyright © 2012 Elsevier Ltd. All rights reserved.

Creation of a longitudinally polarized subwavelength hotspot with an ultra-thin planar lens: vectorial Rayleigh–Sommerfeld method

International Nuclear Information System (INIS)

Ye, Huapeng; Qiu, Cheng-Wei; Huang, Kun; Yeo, Swee Ping; Teng, Jinghua; Luk’yanchuk, Boris

2013-01-01

This letter shows how a longitudinally polarized hotspot can be created by a planar ultra-thin lens that beats the diffraction limit. On the imaging plane, a subwavelength optical resolution 0.39λ with almost purely longitudinal electric component has been demonstrated in air ambient. This novel paradigm addresses simultaneously both longitudinal polarization and deep sub-diffraction imaging, by a planar lens composed of ultra-thin opaque concentric annuli. The vectorial Rayleigh–Sommerfeld (VRS) approach, offering the advantage of significant reduction in computation, has been developed for a particular optimization of a flat lens with full control of polarization. Empowered by the robustness of VRS in dealing with polarization states, the proposed roadmap may be universally and efficiently integrated with other optimization algorithms to design super-resolution imaging with controlled polarization states at any wavelength without luminescence of the object. The lens, which is empowered by the proposed method, opens an avenue for the first time toward a highly integrated imaging system with advanced functionalities in far-field super-imaging, tailored polarization states and flat ultra-thin geometry simultaneously. (letter)

Implementation of a finite element analysis procedure for structural analysis of shape memory behaviour of fibre reinforced shape memory polymer composites

Science.gov (United States)

Azzawi, Wessam Al; Epaarachchi, J. A.; Islam, Mainul; Leng, Jinsong

2017-12-01

Shape memory polymers (SMPs) offer a unique ability to undergo a substantial shape deformation and subsequently recover the original shape when exposed to a particular external stimulus. Comparatively low mechanical properties being the major drawback for extended use of SMPs in engineering applications. However the inclusion of reinforcing fibres in to SMPs improves mechanical properties significantly while retaining intrinsic shape memory effects. The implementation of shape memory polymer composites (SMPCs) in any engineering application is a unique task which requires profound materials and design optimization. However currently available analytical tools have critical limitations to undertake accurate analysis/simulations of SMPC structures and slower derestrict transformation of breakthrough research outcomes to real-life applications. Many finite element (FE) models have been presented. But majority of them require a complicated user-subroutines to integrate with standard FE software packages. Furthermore, those subroutines are problem specific and difficult to use for a wider range of SMPC materials and related structures. This paper presents a FE simulation technique to model the thermomechanical behaviour of the SMPCs using commercial FE software ABAQUS. Proposed technique incorporates material time-dependent viscoelastic behaviour. The ability of the proposed technique to predict the shape fixity and shape recovery was evaluated by experimental data acquired by a bending of a SMPC cantilever beam. The excellent correlation between the experimental and FE simulation results has confirmed the robustness of the proposed technique.

Skin-Inspired Haptic Memory Arrays with an Electrically Reconfigurable Architecture.

Science.gov (United States)

Zhu, Bowen; Wang, Hong; Liu, Yaqing; Qi, Dianpeng; Liu, Zhiyuan; Wang, Hua; Yu, Jiancan; Sherburne, Matthew; Wang, Zhaohui; Chen, Xiaodong

2016-02-24

Skin-inspired haptic-memory devices, which can retain pressure information after the removel of external pressure by virtue of the nonvolatile nature of the memory devices, are achieved. The rise of haptic-memory devices will allow for mimicry of human sensory memory, opening new avenues for the design of next-generation high-performance sensing devices and systems. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Music evokes vivid autobiographical memories.

Science.gov (United States)

Belfi, Amy M; Karlan, Brett; Tranel, Daniel

2016-08-01

Music is strongly intertwined with memories-for example, hearing a song from the past can transport you back in time, triggering the sights, sounds, and feelings of a specific event. This association between music and vivid autobiographical memory is intuitively apparent, but the idea that music is intimately tied with memories, seemingly more so than other potent memory cues (e.g., familiar faces), has not been empirically tested. Here, we compared memories evoked by music to those evoked by famous faces, predicting that music-evoked autobiographical memories (MEAMs) would be more vivid. Participants listened to 30 songs, viewed 30 faces, and reported on memories that were evoked. Memories were transcribed and coded for vividness as in Levine, B., Svoboda, E., Hay, J. F., Winocur, G., & Moscovitch, M. [2002. Aging and autobiographical memory: Dissociating episodic from semantic retrieval. Psychology and Aging, 17, 677-689]. In support of our hypothesis, MEAMs were more vivid than autobiographical memories evoked by faces. MEAMs contained a greater proportion of internal details and a greater number of perceptual details, while face-evoked memories contained a greater number of external details. Additionally, we identified sex differences in memory vividness: for both stimulus categories, women retrieved more vivid memories than men. The results show that music not only effectively evokes autobiographical memories, but that these memories are more vivid than those evoked by famous faces.

Investigation of fast initialization of spacecraft bubble memory systems

Science.gov (United States)

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

1984-01-01

Bubble domain technology offers significant improvement in reliability and functionality for spacecraft onboard memory applications. In considering potential memory systems organizations, minimization of power in high capacity bubble memory systems necessitates the activation of only the desired portions of the memory. In power strobing arbitrary memory segments, a capability of fast turn on is required. Bubble device architectures, which provide redundant loop coding in the bubble devices, limit the initialization speed. Alternate initialization techniques are investigated to overcome this design limitation. An initialization technique using a small amount of external storage is demonstrated.

Transfer matrix representation for periodic planar media

Science.gov (United States)

Parrinello, A.; Ghiringhelli, G. L.

2016-06-01

Sound transmission through infinite planar media characterized by in-plane periodicity is faced by exploiting the free wave propagation on the related unit cells. An appropriate through-thickness transfer matrix, relating a proper set of variables describing the acoustic field at the two external surfaces of the medium, is derived by manipulating the dynamic stiffness matrix related to a finite element model of the unit cell. The adoption of finite element models avoids analytical modeling or the simplification on geometry or materials. The obtained matrix is then used in a transfer matrix method context, making it possible to combine the periodic medium with layers of different nature and to treat both hard-wall and semi-infinite fluid termination conditions. A finite sequence of identical sub-layers through the thickness of the medium can be handled within the transfer matrix method, significantly decreasing the computational burden. Transfer matrices obtained by means of the proposed method are compared with analytical or equivalent models, in terms of sound transmission through barriers of different nature.

Optimization of Phase Change Memory with Thin Metal Inserted Layer on Material Properties

Science.gov (United States)

Harnsoongnoen, Sanchai; Sa-Ngiamsak, Chiranut; Siritaratiwat, Apirat

This works reports, for the first time, the thorough study and optimisation of Phase Change Memory (PCM) structure with thin metal inserted chalcogenide via electrical resistivity (ρ) using finite element modeling. PCM is one of the best candidates for next generation non-volatile memory. It has received much attention recently due to its fast write speed, non-destructive readout, superb scalability, and great compatibility with current silicon-based mass fabrication. The setback of PCM is a high reset current typically higher than 1mA based on 180nm lithography. To reduce the reset current and to solve the over-programming failure, PCM with thin metal inserted chalcogenide (bottom chalcogenide/metal inserted/top chalcogenide) structure has been proposed. Nevertheless, reports on optimisation of the electrical resistivity using the finite element method for this new PCM structure have never been published. This work aims to minimize the reset current of this PCM structure by optimizing the level of the electrical resistivity of the PCM profile using the finite element approach. This work clearly shows that PCM characteristics are strongly affected by the electrical resistivity. The 2-D simulation results reveal clearly that the best thermal transfer of and self-joule-heating at the bottom chalcogenide layer can be achieved under conditions; ρ_bottom chalcogenide > ρ_metal inserted > ρ_top chalcogenide More specifically, the optimized electrical resistivity of PCMTMI is attained with ρ_top chalcogenide: ρ_metal inserted: ρ_bottom chalcogenide ratio of 1:6:16 when ρ_top chalcogenide is 10-3 Ωm. In conclusion, high energy efficiency can be obtained with the reset current as low as 0.3mA and with high speed operation of less than 30ns.

Shape memory polymers

Energy Technology Data Exchange (ETDEWEB)

Wilson, Thomas S.; Bearinger, Jane P.

2017-08-29

New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

Shape memory polymers

Science.gov (United States)

Wilson, Thomas S.; Bearinger, Jane P.

2015-06-09

New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxyl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

On Longest Cycles in Essentially 4-Connected Planar Graphs

Directory of Open Access Journals (Sweden)

Fabrici Igor

2016-08-01

Full Text Available A planar 3-connected graph G is essentially 4-connected if, for any 3-separator S of G, one component of the graph obtained from G by removing S is a single vertex. Jackson and Wormald proved that an essentially 4-connected planar graph on n vertices contains a cycle C such that . For a cubic essentially 4-connected planar graph G, Grünbaum with Malkevitch, and Zhang showed that G has a cycle on at least ¾ n vertices. In the present paper the result of Jackson and Wormald is improved. Moreover, new lower bounds on the length of a longest cycle of G are presented if G is an essentially 4-connected planar graph of maximum degree 4 or G is an essentially 4-connected maximal planar graph.

Synthetic vision and memory for autonomous virtual humans

OpenAIRE

PETERS, CHRISTOPHER; O'SULLIVAN, CAROL ANN

2002-01-01

PUBLISHED A memory model based on ?stage theory?, an influential concept of memory from the field of cognitive psychology, is presented for application to autonomous virtual humans. The virtual human senses external stimuli through a synthetic vision system. The vision system incorporates multiple modes of vision in order to accommodate a perceptual attention approach. The memory model is used to store perceived and attended object information at different stages in a filtering...

Megavoltage planar and cone-beam imaging with low-Z targets: dependence of image quality improvement on beam energy and patient separation.

Science.gov (United States)

Robar, James L; Connell, Tanner; Huang, Weihong; Kelly, Robin G

2009-09-01

The purpose of this study is to investigate the improvement of megavoltage planar and cone-beam CT (CBCT) image quality with the use of low atomic number (Z) external targets in the linear accelerator. In this investigation, two experimental megavoltage imaging beams were generated by using either 3.5 or 7.0 MeV electrons incident on aluminum targets installed above the level of the carousel in a linear accelerator (2100EX, Varian Medical, Inc., Palo Alto, CA). Images were acquired using an amorphous silicon detector panel. Contrast-to-noise ratio (CNR) in planar and CBCT images was measured as a function of dose and a comparison was made between the imaging beams and the standard 6 MV therapy beam. Phantoms of variable diameter were used to examine the loss of contrast due to beam hardening. Porcine imaging was conducted to examine qualitatively the advantages of the low-Z target approach in CBCT. In CBCT imaging CNR increases by factors as high as 2.4 and 4.3 for the 7.0 and 3.5 MeV/Al beams, respectively, compared to images acquired with 6 MV. Similar factors of improvement are observed in planar imaging. For the imaging beams, beam hardening causes a significant loss of the contrast advantage with increasing phantom diameter; however, for the 3.5 MeV/Al beam and a phantom diameter of 25 cm, a contrast advantage remains, with increases of contrast by factors of 1.5 and 3.4 over 6 MV for bone and lung inhale regions, respectively. The spatial resolution is improved slightly in CBCT images for the imaging beams. CBCT images of a porcine cranium demonstrate qualitatively the advantages of the low-Z target approach, showing greater contrast between tissues and improved visibility of fine detail. The use of low-Z external targets in the linear accelerator improves megavoltage planar and CBCT image quality significantly. CNR may be increased by a factor of 4 or greater. Improvement of the spatial resolution is also apparent.

Design principles for single standing nanowire solar cells: going beyond the planar efficiency limits.

Science.gov (United States)

Zeng, Yang; Ye, Qinghao; Shen, Wenzhong

2014-05-09

Semiconductor nanowires (NWs) have long been used in photovoltaic applications but restricted to approaching the fundamental efficiency limits of the planar devices with less material. However, recent researches on standing NWs have started to reveal their potential of surpassing these limits when their unique optical property is utilized in novel manners. Here, we present a theoretical guideline for maximizing the conversion efficiency of a single standing NW cell based on a detailed study of its optical absorption mechanism. Under normal incidence, a standing NW behaves as a dielectric resonator antenna, and its optical cross-section shows its maximum when the lowest hybrid mode (HE11δ) is excited along with the presence of a back-reflector. The promotion of the cell efficiency beyond the planar limits is attributed to two effects: the built-in concentration caused by the enlarged optical cross-section, and the shifting of the absorption front resulted from the excited mode profile. By choosing an optimal NW radius to support the HE11δ mode within the main absorption spectrum, we demonstrate a relative conversion-efficiency enhancement of 33% above the planar cell limit on the exemplary a-Si solar cells. This work has provided a new basis for designing and analyzing standing NW based solar cells.

Attending to auditory memory.

Science.gov (United States)

Zimmermann, Jacqueline F; Moscovitch, Morris; Alain, Claude

2016-06-01

Attention to memory describes the process of attending to memory traces when the object is no longer present. It has been studied primarily for representations of visual stimuli with only few studies examining attention to sound object representations in short-term memory. Here, we review the interplay of attention and auditory memory with an emphasis on 1) attending to auditory memory in the absence of related external stimuli (i.e., reflective attention) and 2) effects of existing memory on guiding attention. Attention to auditory memory is discussed in the context of change deafness, and we argue that failures to detect changes in our auditory environments are most likely the result of a faulty comparison system of incoming and stored information. Also, objects are the primary building blocks of auditory attention, but attention can also be directed to individual features (e.g., pitch). We review short-term and long-term memory guided modulation of attention based on characteristic features, location, and/or semantic properties of auditory objects, and propose that auditory attention to memory pathways emerge after sensory memory. A neural model for auditory attention to memory is developed, which comprises two separate pathways in the parietal cortex, one involved in attention to higher-order features and the other involved in attention to sensory information. This article is part of a Special Issue entitled SI: Auditory working memory. Copyright © 2015 Elsevier B.V. All rights reserved.

Database architecture optimized for the new bottleneck: Memory access

NARCIS (Netherlands)

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

1999-01-01

textabstractIn the past decade, advances in speed of commodity CPUs have far out-paced advances in memory latency. Main-memory access is therefore increasingly a performance bottleneck for many computer applications, including database systems. In this article, we use a simple scan test to show the

Optimizing Database Architecture for the New Bottleneck: Memory Access

NARCIS (Netherlands)

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

2000-01-01

textabstractIn the past decade, advances in speed of commodity CPUs have far out-paced advances in memory latency. Main-memory access is therefore increasingly a performance bottleneck for many computer applications, including database systems. In this article, we use a simple scan test to show the

Observing the amorphous-to-crystalline phase transition in Ge{sub 2}Sb{sub 2}Te{sub 5} non-volatile memory materials from ab initio molecular-dynamics simulations

Energy Technology Data Exchange (ETDEWEB)

Lee, T.H.; Elliott, S.R. [Department of Chemistry, University of Cambridge, Lensfield Road, CB2 1EW Cambridge (United Kingdom)

2012-10-15

Phase-change memory is a promising candidate for the next generation of non-volatile memory devices. This technology utilizes reversible phase transitions between amorphous and crystalline phases of a recording material, and has been successfully used in rewritable optical data storage, revealing its feasibility. In spite of the importance of understanding the nucleation and growth processes that play a critical role in the phase transition, this understanding is still incomplete. Here, we present observations of the early stages of crystallization in Ge{sub 2}Sb{sub 2}Te{sub 5} materials through ab initio molecular-dynamics simulations. Planar structures, including fourfold rings and planes, play an important role in the formation and growth of crystalline clusters in the amorphous matrix. At the same time, vacancies facilitate crystallization by providing space at the glass-crystalline interface for atomic diffusion, which results in fast crystal growth, as observed in simulations and experiments. The microscopic mechanism of crystallization presented here may deepen our understanding of the phase transition occurring in real devices, providing an opportunity to optimize the memory performance of phase-change materials. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Surface planarization effect of siloxane derivatives in organic semiconductor layers

Energy Technology Data Exchange (ETDEWEB)

Sakanoue, Kei [Center for Organic Photonics and Electronics Research, Kyushu University, Nishi-ku, Fukuoka 819-0395 (Japan); Harada, Hironobu; Ando, Kento [Department of Chemical Engineering, Graduate School of Engineering, Kyushu University, Nishi-ku, Fukuoka 819-0395 (Japan); Yahiro, Masayuki [Institute of Systems, Information Technologies and Nanotechnologies, 2-1-22, Sawara-ku, Fukuoka 814-0001 (Japan); Fukai, Jun, E-mail: jfukai@chem-eng.kyushu-u.ac.jp [Department of Chemical Engineering, Graduate School of Engineering, Kyushu University, Nishi-ku, Fukuoka 819-0395 (Japan)

2015-12-31

The ability of siloxane surface control additives (SCAs) to planarize organic semiconductor films with a thickness of tens of nanometers printed on indium tin oxide (ITO) surfaces with stripe-patterned bank structures using a liquid-phase method is demonstrated. Three types of SCAs with different molecular structures are examined in organic solutions of toluene, anisole and tetralin containing N,N′-bis(3-methylphenyl)-N,N′-bis(phenyl)-benzidine as a solute and typical organic semiconductor. While there is an optimum SCA and concentration for each solution, one type of SCA is comprehensively effective for all solutions. This SCA increased contact angle, which is contrary to the typical behavior of SCAs. Scanning electron microscope images of the thin films near the banks reveal that this SCA did not change the contact area between the film and substrate surface, which is related to the effectiveness of the SCA. SCAs did not affect the current–voltage characteristics of green organic light-emitting diodes, but did increase external quantum efficiencies, suggesting that SCAs can be used to improve the quality of solution-deposited films for use in optical devices. - Highlights: • Surface control additives planarize organic semiconductor films coated on surfaces. • The most effective additive increases the contact angle of solutions during drying. • The effect of additives is deduced from solutal Marangoni forces. • Additives have little effect on organic light-emitting diode performance.

Surface planarization effect of siloxane derivatives in organic semiconductor layers

International Nuclear Information System (INIS)

Sakanoue, Kei; Harada, Hironobu; Ando, Kento; Yahiro, Masayuki; Fukai, Jun

2015-01-01

The ability of siloxane surface control additives (SCAs) to planarize organic semiconductor films with a thickness of tens of nanometers printed on indium tin oxide (ITO) surfaces with stripe-patterned bank structures using a liquid-phase method is demonstrated. Three types of SCAs with different molecular structures are examined in organic solutions of toluene, anisole and tetralin containing N,N′-bis(3-methylphenyl)-N,N′-bis(phenyl)-benzidine as a solute and typical organic semiconductor. While there is an optimum SCA and concentration for each solution, one type of SCA is comprehensively effective for all solutions. This SCA increased contact angle, which is contrary to the typical behavior of SCAs. Scanning electron microscope images of the thin films near the banks reveal that this SCA did not change the contact area between the film and substrate surface, which is related to the effectiveness of the SCA. SCAs did not affect the current–voltage characteristics of green organic light-emitting diodes, but did increase external quantum efficiencies, suggesting that SCAs can be used to improve the quality of solution-deposited films for use in optical devices. - Highlights: • Surface control additives planarize organic semiconductor films coated on surfaces. • The most effective additive increases the contact angle of solutions during drying. • The effect of additives is deduced from solutal Marangoni forces. • Additives have little effect on organic light-emitting diode performance.

'More is less'. The tax effects of ignoring flow externalities

International Nuclear Information System (INIS)

Sandal, Leif K.; Steinshamn, Stein Ivar; Grafton, R. Quentin

2003-01-01

Using a model of non-linear, non-monotone decay of the stock pollutant, and starting from the same initial conditions, the paper shows that an optimal tax that corrects for both stock and flow externalities may result in a lower tax, fewer cumulative emissions (less decay in emissions) and higher output at the steady state than a corrective tax that ignores the flow externality. This 'more is less' result emphasizes that setting a corrective tax that ignores the flow externality, or imposing a corrective tax at too low a level where there exists only a stock externality, may affect both transitory and steady-state output, tax payments and cumulative emissions. The result has important policy implications for decision makers setting optimal corrective taxes and targeted emission limits whenever stock externalities exist

An Optimized Online Verification Imaging Procedure for External Beam Partial Breast Irradiation

International Nuclear Information System (INIS)

Willis, David J.; Kron, Tomas; Chua, Boon

2011-01-01

The purpose of this study was to evaluate the capabilities of a kilovoltage (kV) on-board imager (OBI)-equipped linear accelerator in the setting of on-line verification imaging for external-beam partial breast irradiation. Available imaging techniques were optimized and assessed for image quality using a modified anthropomorphic phantom. Imaging dose was also assessed. Imaging techniques were assessed for physical clearance between patient and treatment machine using a volunteer. Nonorthogonal kV image pairs were identified as optimal in terms of image quality, clearance, and dose. After institutional review board approval, this approach was used for 17 patients receiving accelerated partial breast irradiation. Imaging was performed before every fraction verification with online correction of setup deviations >5 mm (total image sessions = 170). Treatment staff rated risk of collision and visibility of tumor bed surgical clips where present. Image session duration and detected setup deviations were recorded. For all cases, both image projections (n = 34) had low collision risk. Surgical clips were rated as well as visualized in all cases where they were present (n = 5). The average imaging session time was 6 min, 16 sec, and a reduction in duration was observed as staff became familiar with the technique. Setup deviations of up to 1.3 cm were detected before treatment and subsequently confirmed offline. Nonorthogonal kV image pairs allowed effective and efficient online verification for partial breast irradiation. It has yet to be tested in a multicenter study to determine whether it is dependent on skilled treatment staff.

CPU and cache efficient management of memory-resident databases

NARCIS (Netherlands)

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

2013-01-01

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

CPU and Cache Efficient Management of Memory-Resident Databases

NARCIS (Netherlands)

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

2013-01-01

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

Planar half-cell shaped precursor body

DEFF Research Database (Denmark)

2015-01-01

The invention relates to a half-cell shaped precursor body of either anode type or cathode type, the half-cell shaped precursor body being prepared to be free sintered to form a sintered or pre-sintered half-cell being adapted to be stacked in a solid oxide fuel cell stack. The obtained half......-cell has an improved planar shape, which remains planar also after a sintering process and during temperature fluctuations....

Assessing the efficacy of vesicle fusion with planar membrane arrays using a mitochondrial porin as reporter

DEFF Research Database (Denmark)

Pszon-Bartosz, Kamila Justyna; Hansen, Jesper S.; Stibius, Karin B.

2011-01-01

Reconstitution of functionally active membrane protein into artificially made lipid bilayers is a challenge that must be overcome to create a membrane-based biomimetic sensor and separation device. In this study we address the efficacy of proteoliposome fusion with planar membrane arrays. We...... establish a protein incorporation efficacy assay using the major non-specific porin of Fusobacterium nucleatum (FomA) as reporter. We use electrical conductance measurements and fluorescence microscopy to characterize proteoliposome fusion with an array of planar membranes. We show that protein...... reconstitution in biomimetic membrane arrays may be quantified using the developed FomA assay. Specifically, we show that FomA vesicles are inherently fusigenic. Optimal FomA incorporation is obtained with a proteoliposome lipid-to-protein molar ratio (LPR)=50 more than 105 FomA proteins could be incorporated...

Synthesis of shape memory alloys using electrodeposition

Science.gov (United States)

Hymer, Timothy Roy

Shape memory alloys are used in a variety of applications. The area of micro-electro-mechanical systems (MEMS) is a developing field for thin film shape memory alloys for making actuators, valves and pumps. Until recently thin film shape memory alloys could only be made by rapid solidification or sputtering techniques which have the disadvantage of being "line of sight". At the University of Missouri-Rolla, electrolytic techniques have been developed that allow the production of shape memory alloys in thin film form. The advantages of this techniques are in-situ, non "line of sight" and the ability to make differing properties of the shape memory alloys from one bath. This research focused on the electrodeposition of In-Cd shape memory alloys. The primary objective was to characterize the electrodeposited shape memory effect for an electrodeposited shape memory alloy. The effect of various operating parameters such as peak current density, temperature, pulsing, substrate and agitation were investigated and discussed. The electrodeposited alloys were characterized by relative shape memory effect, phase transformation, morphology and phases present. Further tests were performed to optimize the shape memory by the use of a statistically designed experiment. An optimized shape memory effect for an In-Cd alloy is reported for the conditions of the experiments.

Tuner and radiation shield for planar electron paramagnetic resonance microresonators

International Nuclear Information System (INIS)

Narkowicz, Ryszard; Suter, Dieter

2015-01-01

Planar microresonators provide a large boost of sensitivity for small samples. They can be manufactured lithographically to a wide range of target parameters. The coupler between the resonator and the microwave feedline can be integrated into this design. To optimize the coupling and to compensate manufacturing tolerances, it is sometimes desirable to have a tuning element available that can be adjusted when the resonator is connected to the spectrometer. This paper presents a simple design that allows one to bring undercoupled resonators into the condition for critical coupling. In addition, it also reduces radiation losses and thereby increases the quality factor and the sensitivity of the resonator

Attractive planar panelization using dynamic relaxation principles

NARCIS (Netherlands)

Gauss, Florian; Teuffel, Patrick

2015-01-01

In the presented paper a new method is proposed to approximate a given NURBS surface with a PQ (Planar Quad) mesh. The desired mesh layout will be generated in then attracted to the target surface. The process iteratively pulls the mesh vertices towards the target surface and then planarizes the

Planar Hall effect bridge magnetic field sensors

DEFF Research Database (Denmark)

Henriksen, A.D.; Dalslet, Bjarke Thomas; Skieller, D.H.

2010-01-01

Until now, the planar Hall effect has been studied in samples with cross-shaped Hall geometry. We demonstrate theoretically and experimentally that the planar Hall effect can be observed for an exchange-biased ferromagnetic material in a Wheatstone bridge topology and that the sensor signal can...... Hall effect bridge sensors....

Column Planarity and Partially-Simultaneous Geometric Embedding

Czech Academy of Sciences Publication Activity Database

Barba, L.; Evans, W.; Hoffmann, M.; Kusters, V.; Saumell, Maria; Speckmann, B.

2017-01-01

Roč. 21, č. 6 (2017), s. 983-1002 ISSN 1526-1719 Grant - others:GA MŠk(CZ) LO1506; GA MŠk(CZ) EE2.3.30.0038 Institutional support: RVO:67985807 Keywords : column planarity * unlabeled level planarity * simultaneous geometric embedding Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics

Pulsed laser planarization of metal films for multilevel interconnects

International Nuclear Information System (INIS)

Tuckerman, D.B.; Schmitt, R.L.

1985-05-01

Multilevel interconnect schemes for integrated circuits generally require one or more planarization steps, in order to maintain an acceptably flat topography for lithography and thin-film step coverage on the higher levels. Traditional approaches have involved planarization of the interlevel insulation (dielectric) layers, either by spin-on application (e.g., polyimide), or by reflow (e.g., phosphosilicate glass). We have pursued an alternative approach, in which each metal level is melted (hence planarized) using a pulsed laser prior to patterning. Short (approx.1 μs) pulses are used to preclude undesirable metallurgical reactions between the film, adhesion or barrier layer, and dielectric layer. Laser planarization of metals is particularly well suited to multilevel systems which include ground or power planes. Results are presented for planarization of gold films on SiO 2 dielectric layers using a flashlamp-pumped dye laser. The pulse duration is approx.1 μs, which allows the heat pulse to uniformly penetrate the gold while not penetrating substantially through the underlying SiO 2 (hence not perturbing the lower levels of metal). Excellent planarization of the gold films is achieved (less than 0.1 μm surface roughness, even starting with extreme topographic variations), as well as improved conductivity. To demonstrate the process, numerous planarized two-layer structures (transmission lines under a ground plane) were fabricated and characterized. 9 refs., 2 figs

Prefrontal Cortex Networks Shift from External to Internal Modes during Learning

Science.gov (United States)

Brincat, Scott L.

2016-01-01

As we learn about items in our environment, their neural representations become increasingly enriched with our acquired knowledge. But there is little understanding of how network dynamics and neural processing related to external information changes as it becomes laden with “internal” memories. We sampled spiking and local field potential activity simultaneously from multiple sites in the lateral prefrontal cortex (PFC) and the hippocampus (HPC)—regions critical for sensory associations—of monkeys performing an object paired-associate learning task. We found that in the PFC, evoked potentials to, and neural information about, external sensory stimulation decreased while induced beta-band (∼11–27 Hz) oscillatory power and synchrony associated with “top-down” or internal processing increased. By contrast, the HPC showed little evidence of learning-related changes in either spiking activity or network dynamics. The results suggest that during associative learning, PFC networks shift their resources from external to internal processing. SIGNIFICANCE STATEMENT As we learn about items in our environment, their representations in our brain become increasingly enriched with our acquired “top-down” knowledge. We found that in the prefrontal cortex, but not the hippocampus, processing of external sensory inputs decreased while internal network dynamics related to top-down processing increased. The results suggest that during learning, prefrontal cortex networks shift their resources from external (sensory) to internal (memory) processing. PMID:27629722

Destination memory in Alzheimer's Disease: when I imagine telling Ronald Reagan about Paris.

Science.gov (United States)

El Haj, Mohamad; Postal, Virginie; Allain, Philippe

2013-01-01

Destination memory refers to remembering the destination of information that people output. This present paper establishes a new distinction between external and internal processes within this memory system for both normal aging and Alzheimer's Disease (AD). Young adults, older adults, and mild AD patients were asked either to tell facts (i.e., external destination memory condition) or to imagine telling facts (i.e., internal destination memory condition) to pictures of famous people. The experiment established three major findings. First, the destination memory performance of the AD patients was significantly poorer than that of older adults, which in turn was poorer than that of the young adults. Furthermore, internal destination processes were more prone to being forgotten than external destination memory processes. In other words, participants had more difficulty in remembering whether they had previously imagined telling the facts to the pictures or not (i.e., imagined condition) than in remembering whether they had previously told the facts to the pictures or not (i.e., enacted condition). Second, significant correlations were detected between performances on destination memory and several executive measures such as the Stroop, the Plus-Minus and the Binding tasks. Third, among the executive measures, regression analyses showed that performance on the Stroop task was a main factor in explaining variance in destination memory performance. Our findings reflect the difficulty in remembering the destination of internally generated information. They also demonstrate the involvement of inhibitory processes in destination memory. Copyright © 2011 Elsevier Ltd. All rights reserved.

External and Internal Impact on Soviet Memorial Landscape Development by THE World War II

Directory of Open Access Journals (Sweden)

Alexandra Cherkasski

2012-11-01

Full Text Available The World War II led to serious casualties and left deep scars / wounds of memory. As the victory over occupation regime was glorified, honored and starting from 1965 was widely celebrated at national level, there was a great gap between official and personal memory of war. Monuments are one of the forms of living examples of the past and thus are reliable sources for the study of different epochs and Zeitgeist / spirit of time and their changes. This article considers the development of Soviet memorial landscape by the World War II starting from the war termination to the Soviet Union collapse. Special attention is attached to internal political and international views / interpretations and development with respect to victims of war. In other words, the process of different groups of war victims exclusion and inclusion in Soviet collective memory under the influence of internal political and foreign political interests symbiosis. And, as a result, resultant attitude towards memorial places.

Such stuff as dreams are made on? Elaborative encoding, the ancient art of memory, and the hippocampus.

Science.gov (United States)

Llewellyn, Sue

2013-12-01

This article argues that rapid eye movement (REM) dreaming is elaborative encoding for episodic memories. Elaborative encoding in REM can, at least partially, be understood through ancient art of memory (AAOM) principles: visualization, bizarre association, organization, narration, embodiment, and location. These principles render recent memories more distinctive through novel and meaningful association with emotionally salient, remote memories. The AAOM optimizes memory performance, suggesting that its principles may predict aspects of how episodic memory is configured in the brain. Integration and segregation are fundamental organizing principles in the cerebral cortex. Episodic memory networks interconnect profusely within the cortex, creating omnidirectional "landmark" junctions. Memories may be integrated at junctions but segregated along connecting network paths that meet at junctions. Episodic junctions may be instantiated during non-rapid eye movement (NREM) sleep after hippocampal associational function during REM dreams. Hippocampal association involves relating, binding, and integrating episodic memories into a mnemonic compositional whole. This often bizarre, composite image has not been present to the senses; it is not "real" because it hyperassociates several memories. During REM sleep, on the phenomenological level, this composite image is experienced as a dream scene. A dream scene may be instantiated as omnidirectional neocortical junction and retained by the hippocampus as an index. On episodic memory retrieval, an external stimulus (or an internal representation) is matched by the hippocampus against its indices. One or more indices then reference the relevant neocortical junctions from which episodic memories can be retrieved. Episodic junctions reach a processing (rather than conscious) level during normal wake to enable retrieval. If this hypothesis is correct, the stuff of dreams is the stuff of memory.

Planar Elongation Measurements on Soft Elastomers

DEFF Research Database (Denmark)

Jensen, Mette Krog; Skov, Anne Ladegaard; Rasmussen, Henrik K.

2009-01-01

A new fixture to the filament stretch rheometer (FSR) has been developed to measure planar elongation of soft polymeric networks. To validate this new technique, soft polymeric networks of poly(propyleneoxide) (PPO) were investigated during deformation.......A new fixture to the filament stretch rheometer (FSR) has been developed to measure planar elongation of soft polymeric networks. To validate this new technique, soft polymeric networks of poly(propyleneoxide) (PPO) were investigated during deformation....

Planar metasurface retroreflector

Science.gov (United States)

Arbabi, Amir; Arbabi, Ehsan; Horie, Yu; Kamali, Seyedeh Mahsa; Faraon, Andrei

2017-07-01

Metasurfaces are two-dimensional arrangements of subwavelength scatterers that control the propagation of optical waves. Here, we show that cascaded metasurfaces, each performing a predefined mathematical transformation, provide a new optical design framework that enables new functionalities not yet demonstrated with single metasurfaces. Specifically, we demonstrate that retroreflection can be achieved with two vertically stacked planar metasurfaces, the first performing a spatial Fourier transform and its inverse, and the second imparting a spatially varying momentum to the Fourier transform of the incident light. Using this concept, we fabricate and test a planar monolithic near-infrared retroreflector composed of two layers of silicon nanoposts, which reflects light along its incident direction with a normal incidence efficiency of 78% and a large half-power field of view of 60°. The metasurface retroreflector demonstrates the potential of cascaded metasurfaces for implementing novel high-performance components, and enables low-power and low-weight passive optical transmitters.

SPECT imaging in evaluating extent of malignant external otitis: case report

International Nuclear Information System (INIS)

English, R.J.; Tu'Meh, S.S.; Piwnica-Worms, D.; Holman, B.L.

1987-01-01

Otitis externa, a benign inflammatory process of the external auditory canal, is general responsive to local therapy. Some patients however, develop a less controllable disease leading to chondritis and osteomyelitis of the base of the skull. The direct invasive characteristic of the disease has led to the descriptive term malignant external otitis (MEO), more appropriately called necrotizing or invasive external otitis. Malignant external otitis is caused by an aggressive pseudomonas or proteus infection that almost exclusively occurs in elderly diabetic patients. The primary imaging modalities previously used in the diagnosis and evaluation of MEO were standard planar scintigraphic techniques with technetium-99M (/sup 99m/Tc) bone agents and gallium-67 ( 67 Ga), and pluridirectional tomography. The advent of high resolution computed tomography (CT) effectively allowed demonstration of the soft tissue extension and bone destruction associated with MEO, but still suffered from the low sensitivity constraints of all radiographic techniques in determining early inflammatory bone involvement. Recent work suggests that scintigraphic detection of MEO with /sup 99m/Tc-MDP and 67 Ga, combined with the cross-sectional resolution of single photon emission computed tomography (SPECT) may be of value in planning treatment of this inflammatory condition

An architecture for integrating planar and 3D cQED devices

Energy Technology Data Exchange (ETDEWEB)

Axline, C.; Reagor, M.; Heeres, R.; Reinhold, P.; Wang, C.; Shain, K.; Pfaff, W.; Chu, Y.; Frunzio, L.; Schoelkopf, R. J. [Department of Applied Physics, Yale University, New Haven, Connecticut 06511 (United States)

2016-07-25

Numerous loss mechanisms can limit coherence and scalability of planar and 3D-based circuit quantum electrodynamics (cQED) devices, particularly due to their packaging. The low loss and natural isolation of 3D enclosures make them good candidates for coherent scaling. We introduce a coaxial transmission line device architecture with coherence similar to traditional 3D cQED systems. Measurements demonstrate well-controlled external and on-chip couplings, a spectrum absent of cross-talk or spurious modes, and excellent resonator and qubit lifetimes. We integrate a resonator-qubit system in this architecture with a seamless 3D cavity, and separately pattern a qubit, readout resonator, Purcell filter, and high-Q stripline resonator on a single chip. Device coherence and its ease of integration make this a promising tool for complex experiments.

A graphene-based non-volatile memory

Science.gov (United States)

Loisel, Loïc.; Maurice, Ange; Lebental, Bérengère; Vezzoli, Stefano; Cojocaru, Costel-Sorin; Tay, Beng Kang

2015-09-01

We report on the development and characterization of a simple two-terminal non-volatile graphene switch. After an initial electroforming step during which Joule heating leads to the formation of a nano-gap impeding the current flow, the devices can be switched reversibly between two well-separated resistance states. To do so, either voltage sweeps or pulses can be used, with the condition that VSET achieve reversible switching on more than 100 cycles with resistance ratio values of 104. This approach of graphene memory is competitive as compared to other graphene approaches such as redox of graphene oxide, or electro-mechanical switches with suspended graphene. We suggest a switching model based on a planar electro-mechanical switch, whereby electrostatic, elastic and friction forces are competing to switch devices ON and OFF, and the stability in the ON state is achieved by the formation of covalent bonds between the two stretched sides of the graphene, hence bridging the nano-gap. Developing a planar electro-mechanical switch enables to obtain the advantages of electro-mechanical switches while avoiding most of their drawbacks.

A Rectangular Planar Spiral Antenna for GIS Partial Discharge Detection

Directory of Open Access Journals (Sweden)

Xiaoxing Zhang

2014-01-01

Full Text Available A rectangular planar spiral antenna sensor was designed for detecting the partial discharge in gas insulation substations (GIS. It can expediently receive electromagnetic waves leaked from basin-type insulators and can effectively suppress low frequency electromagnetic interference from the surrounding environment. Certain effective techniques such as rectangular spiral structure, bow-tie loading, and back cavity structure optimization during the antenna design process can miniaturize antenna size and optimize voltage standing wave ratio (VSWR characteristics. Model calculation and experimental data measured in the laboratory show that the antenna possesses a good radiating performance and a multiband property when working in the ultrahigh frequency (UHF band. A comparative study between characteristics of the designed antenna and the existing quasi-TEM horn antenna was made. Based on the GIS defect simulation equipment in the laboratory, partial discharge signals were detected by the designed antenna, the available quasi-TEM horn antenna, and the microstrip patch antenna, and the measurement results were compared.

A Cooperative Harmony Search Algorithm for Function Optimization

Directory of Open Access Journals (Sweden)

Gang Li

2014-01-01

Full Text Available Harmony search algorithm (HS is a new metaheuristic algorithm which is inspired by a process involving musical improvisation. HS is a stochastic optimization technique that is similar to genetic algorithms (GAs and particle swarm optimizers (PSOs. It has been widely applied in order to solve many complex optimization problems, including continuous and discrete problems, such as structure design, and function optimization. A cooperative harmony search algorithm (CHS is developed in this paper, with cooperative behavior being employed as a significant improvement to the performance of the original algorithm. Standard HS just uses one harmony memory and all the variables of the object function are improvised within the harmony memory, while the proposed algorithm CHS uses multiple harmony memories, so that each harmony memory can optimize different components of the solution vector. The CHS was then applied to function optimization problems. The results of the experiment show that CHS is capable of finding better solutions when compared to HS and a number of other algorithms, especially in high-dimensional problems.

Genetic evolutionary taboo search for optimal marker placement in infrared patient setup

International Nuclear Information System (INIS)

Riboldi, M; Baroni, G; Spadea, M F; Tagaste, B; Garibaldi, C; Cambria, R; Orecchia, R; Pedotti, A

2007-01-01

In infrared patient setup adequate selection of the external fiducial configuration is required for compensating inner target displacements (target registration error, TRE). Genetic algorithms (GA) and taboo search (TS) were applied in a newly designed approach to optimal marker placement: the genetic evolutionary taboo search (GETS) algorithm. In the GETS paradigm, multiple solutions are simultaneously tested in a stochastic evolutionary scheme, where taboo-based decision making and adaptive memory guide the optimization process. The GETS algorithm was tested on a group of ten prostate patients, to be compared to standard optimization and to randomly selected configurations. The changes in the optimal marker configuration, when TRE is minimized for OARs, were specifically examined. Optimal GETS configurations ensured a 26.5% mean decrease in the TRE value, versus 19.4% for conventional quasi-Newton optimization. Common features in GETS marker configurations were highlighted in the dataset of ten patients, even when multiple runs of the stochastic algorithm were performed. Including OARs in TRE minimization did not considerably affect the spatial distribution of GETS marker configurations. In conclusion, the GETS algorithm proved to be highly effective in solving the optimal marker placement problem. Further work is needed to embed site-specific deformation models in the optimization process

Label-based routing for a family of scale-free, modular, planar and unclustered graphs

International Nuclear Information System (INIS)

Comellas, Francesc; Miralles, Alicia

2011-01-01

We give an optimal labeling and routing algorithm for a family of scale-free, modular and planar graphs with zero clustering. The relevant properties of this family match those of some networks associated with technological and biological systems with a low clustering, including some electronic circuits and protein networks. The existence of an efficient routing protocol for this graph model should help when designing communication algorithms in real networks and also in the understanding of their dynamic processes.

The Role of Working Memory in the Probabilistic Inference of Future Sensory Events.

Science.gov (United States)

Cashdollar, Nathan; Ruhnau, Philipp; Weisz, Nathan; Hasson, Uri

2017-05-01

The ability to represent the emerging regularity of sensory information from the external environment has been thought to allow one to probabilistically infer future sensory occurrences and thus optimize behavior. However, the underlying neural implementation of this process is still not comprehensively understood. Through a convergence of behavioral and neurophysiological evidence, we establish that the probabilistic inference of future events is critically linked to people's ability to maintain the recent past in working memory. Magnetoencephalography recordings demonstrated that when visual stimuli occurring over an extended time series had a greater statistical regularity, individuals with higher working-memory capacity (WMC) displayed enhanced slow-wave neural oscillations in the θ frequency band (4-8 Hz.) prior to, but not during stimulus appearance. This prestimulus neural activity was specifically linked to contexts where information could be anticipated and influenced the preferential sensory processing for this visual information after its appearance. A separate behavioral study demonstrated that this process intrinsically emerges during continuous perception and underpins a realistic advantage for efficient behavioral responses. In this way, WMC optimizes the anticipation of higher level semantic concepts expected to occur in the near future. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Chaotic non-planar vibrations of the thin elastica. Part I: Experimental observation of planar instability

Science.gov (United States)

Cusumano, J. P.; Moon, F. C.

1995-01-01

In this two-part paper, the results of an investigation into the non-linear dynamics of a flexible cantilevered rod (the elastica) with a thin rectangular cross-section are presented. An experimental examination of the dynamics of the elastica over a broad parameter range forms the core of Part I. In Part II, the experimental work is related to a theoretical study of the mechanics of the elastica, and the study of a two-degree-of-freedom model obtained by modal projection. The experimental system used in this investigation is a rod with clamped-free boundary conditions, forced by sinusoidally displacing the clamped end. Planar periodic motions of the driven elastica are shown to lose stability at distinct resonant wedges, and the resulting motions are shown in general to be non-planar, chaotic, bending-torsion oscillations. Non-planar motions in all resonances exhibit energy cascading and dynamic two-well phenomena, and a family of asymmetric, bending-torsion non-linear modes is discovered. Correlation dimension calculations are used to estimate the number of active degrees of freedom in the system.

No deficits in nonverbal memory, metamemory and internal as well as external source memory in obsessive-compulsive disorder (OCD).

Science.gov (United States)

Moritz, Steffen; Ruhe, Claudia; Jelinek, Lena; Naber, Dieter

2009-04-01

A large body of literature suggests that some symptoms of obsessive-compulsive disorder (OCD) result from mnemonic dysfunctions. The present study tested various formulations of the memory deficit hypothesis considering important moderators, such as depression and response slowing. Thirty-two OCD patients and 32 healthy controls were presented verbal or nonverbal instructions for actions (e.g. simple gestures). These actions should either be performed or imagined. For recognition, previously presented as well as novel actions were displayed. Decisions had to be made whether an action was previously displayed (verbally vs. nonverbally) or not and whether an action was performed or imagined (internal source memory). Moreover, both judgments required confidence ratings. Groups did not differ in memory accuracy and metamemory for verbally presented material. Patients displayed some impairment for nonverbally presented material and imagined instructions, which, however, could be fully accounted for by response slowing and depressive symptoms. The study challenges the view that primary memory deficits underlie OCD or any of its subtypes. We claim that research should move forward from the mere study of objective impairment to the assessment of cognitive performance in conjunction with personality traits such as inflated responsibility.

Estimation of the Optimal Location of Metallic Objects Inside a Mobile Phone

DEFF Research Database (Denmark)

Thaysen, Jesper; Jakobsen, Kaj Bjarne

2005-01-01

Planar near-field measurements of the electric field components are used to determine where to place external components, such as a loudspeaker or camera, without significantly affecting the radiated field. The location of the peak value of the electric field is discussed. The three principal ele...

Focus of Attention in Children's Motor Learning: Examining the Role of Age and Working Memory.

Science.gov (United States)

Brocken, J E A; Kal, E C; van der Kamp, J

2016-01-01

The authors investigated the relative effectiveness of different attentional focus instructions on motor learning in primary school children. In addition, we explored whether the effect of attentional focus on motor learning was influenced by children's age and verbal working memory capacity. Novice 8-9-year old children (n = 30) and 11-12-year-old children (n = 30) practiced a golf putting task. For each age group, half the participants received instructions to focus (internally) on the swing of their arm, while the other half was instructed to focus (externally) on the swing of the club. Children's verbal working memory capacity was assessed with the Automated Working Memory Assessment. Consistent with many reports on adult's motor learning, children in the external groups demonstrated greater improvements in putting accuracy than children who practiced with an internal focus. This effect was similar across age groups. Verbal working memory capacity was not found to be predictive of motor learning, neither for children in the internal focus groups nor for children in the external focus groups. In conclusion, primary school children's motor learning is enhanced by external focus instructions compared to internal focus instructions. The purported modulatory roles of children's working memory, attentional capacity, or focus preferences require further investigation.

A Novel Multiband Miniature Planar Inverted F Antenna Design for Bluetooth and WLAN Applications

Directory of Open Access Journals (Sweden)

J. M. Jeevani W. Jayasinghe

2015-01-01

Full Text Available A novel compact planar inverted F antenna (PIFA optimized using genetic algorithms for 2.4 GHz (Bluetooth and 5 GHz (UNII-1, UNII-2, UNII-2 extended, and UNII-3 bands is presented. The patch with a shorting pin is on a 20×7×0.762 mm3 substrate, which is suspended in air 5 mm above a 30×7 mm2 ground plane. Genetic algorithm optimization (GAO is used to optimize the patch geometry, feed position, and shorting pin position simultaneously. Simulations are carried out by using HFSS and a prototype antenna is fabricated to compare the measurements with the simulations. The antenna shows fractional impedance bandwidths of 4% and 21% and gains of 2.5 dB and 3.2 dB at lower and upper bands, respectively.

Belief propagation and loop series on planar graphs

International Nuclear Information System (INIS)

Chertkov, Michael; Teodorescu, Razvan; Chernyak, Vladimir Y

2008-01-01

We discuss a generic model of Bayesian inference with binary variables defined on edges of a planar graph. The Loop Calculus approach of Chertkov and Chernyak (2006 Phys. Rev. E 73 065102(R) [cond-mat/0601487]; 2006 J. Stat. Mech. P06009 [cond-mat/0603189]) is used to evaluate the resulting series expansion for the partition function. We show that, for planar graphs, truncating the series at single-connected loops reduces, via a map reminiscent of the Fisher transformation (Fisher 1961 Phys. Rev. 124 1664), to evaluating the partition function of the dimer-matching model on an auxiliary planar graph. Thus, the truncated series can be easily re-summed, using the Pfaffian formula of Kasteleyn (1961 Physics 27 1209). This allows us to identify a big class of computationally tractable planar models reducible to a dimer model via the Belief Propagation (gauge) transformation. The Pfaffian representation can also be extended to the full Loop Series, in which case the expansion becomes a sum of Pfaffian contributions, each associated with dimer matchings on an extension to a subgraph of the original graph. Algorithmic consequences of the Pfaffian representation, as well as relations to quantum and non-planar models, are discussed

Visual working memory as visual attention sustained internally over time.

Science.gov (United States)

Chun, Marvin M

2011-05-01

Visual working memory and visual attention are intimately related, such that working memory encoding and maintenance reflects actively sustained attention to a limited number of visual objects and events important for ongoing cognition and action. Although attention is typically considered to operate over perceptual input, a recent taxonomy proposes to additionally consider how attention can be directed to internal perceptual representations in the absence of sensory input, as well as other internal memories, choices, and thoughts (Chun, Golomb, & Turk-Browne, 2011). Such internal attention enables prolonged binding of features into integrated objects, along with enhancement of relevant sensory mechanisms. These processes are all limited in capacity, although different types of working memory and attention, such as spatial vs. object processing, operate independently with separate capacity. Overall, the success of maintenance depends on the ability to inhibit both external (perceptual) and internal (cognitive) distraction. Working memory is the interface by which attentional mechanisms select and actively maintain relevant perceptual information from the external world as internal representations within the mind. Copyright © 2011. Published by Elsevier Ltd.

Effects of assistant anode on planar inductively coupled magnetized argon plasma in plasma immersion ion implantation

International Nuclear Information System (INIS)

Tang, Deli; Chu, Paul K.

2003-01-01

The enhancement of planar radio frequency (RF) inductively coupled argon plasma is studied in the presence of an assistant anode and an external magnetic field at low pressure. The influence of the assistant anode and magnetic field on the efficiency of RF power absorption and plasma parameters is investigated. An external axial magnetic field is coupled into the plasma discharge region by an external electromagnetic coil outside the discharge chamber and an assistant cylindrical anode is inserted into the discharge chamber to enhance the plasma discharge. The plasma parameters and density profile are measured by an electrostatic Langmuir probe at different magnetic fields and anode voltages. The RF power absorption by the plasma can be effectively enhanced by the external magnetic field compared with the nonmagnetized discharge. The plasma density can be further increased by the application of a voltage to the assistant anode. Owing to the effective power absorption and enhanced plasma discharge by the assistant anode in a longitudinal magnetic field, the plasma density can be enhanced by more than a factor of two. Meanwhile, the nonuniformity of the plasma density is less than 10% and it can be achieved in a process chamber with a diameter of 600 mm

Shape Memory of Human Red Blood Cells

OpenAIRE

Fischer, Thomas M.

2004-01-01

The human red cell can be deformed by external forces but returns to the biconcave resting shape after removal of the forces. If after such shape excursions the rim is always formed by the same part of the membrane, the cell is said to have a memory of its biconcave shape. If the rim can form anywhere on the membrane, the cell would have no shape memory. The shape memory was probed by an experiment called go-and-stop. Locations on the membrane were marked by spontaneously adhering latex spher...

Planar quantum squeezing and atom interferometry

Energy Technology Data Exchange (ETDEWEB)

He, Q. Y.; Drummond, P. D.; Reid, M. D. [ARC Centre of Excellence for Quantum-Atom Optics, Centre for Atom Optics and Ultrafast Spectroscopy, Swinburne University of Technology, Melbourne 3122 (Australia); Peng Shiguo [Department of Physics, Tsinghua University, Beijing 100084 (China)

2011-08-15

We obtain a lower bound on the sum of two orthogonal spin component variances in a plane. This gives a planar uncertainty relation which holds even when the Heisenberg relation is not useful. We investigate the asymptotic, large-J limit and derive the properties of the planar quantum squeezed states that saturate this uncertainty relation. These states extend the concept of spin squeezing to any two conjugate spin directions. We show that planar quantum squeezing can be achieved experimentally as the ground state of a Bose-Einstein condensate in two coupled potential wells with a critical attractive interaction. These states reduce interferometric phase noise at all phase angles simultaneously. This is useful for one-shot interferometric phase measurements where the measured phase is completely unknown. Our results can also be used to derive entanglement criteria for multiple spins J at separated sites, with applications in quantum information.

Parietal EEG alpha suppression time of memory retrieval reflects memory load while the alpha power of memory maintenance is a composite of the visual process according to simultaneous and successive Sternberg memory tasks.

Science.gov (United States)

Okuhata, Shiho; Kusanagi, Takuya; Kobayashi, Tetsuo

2013-10-25

The present study investigated EEG alpha activity during visual Sternberg memory tasks using two different stimulus presentation modes to elucidate how the presentation mode affected parietal alpha activity. EEGs were recorded from 10 healthy adults during the Sternberg tasks in which memory items were presented simultaneously and successively. EEG power and suppression time (ST) in the alpha band (8-13Hz) were computed for the memory maintenance and retrieval phases. The alpha activity differed according to the presentation mode during the maintenance phase but not during the retrieval phase. Results indicated that parietal alpha power recorded during the maintenance phase did not reflect the memory load alone. In contrast, ST during the retrieval phase increased with the memory load for both presentation modes, indicating a serial memory scanning process, regardless of the presentation mode. These results indicate that there was a dynamic transition in the memory process from the maintenance phase, which was sensitive to external factors, toward the retrieval phase, during which the process converged on the sequential scanning process, the Sternberg task essentially required. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

Searching for planar signatures in WMAP

International Nuclear Information System (INIS)

Abramo, L. Raul; Bernui, Armando; Pereira, Thiago S.

2009-01-01

We search for planar deviations of statistical isotropy in the Wilkinson Microwave Anisotropy Probe (WMAP) data by applying a recently introduced angular-planar statistics both to full-sky and to masked temperature maps, including in our analysis the effect of the residual foreground contamination and systematics in the foreground removing process as sources of error. We confirm earlier findings that full-sky maps exhibit anomalies at the planar (l) and angular (l) scales (l,l) = (2,5),(4,7), and (6,8), which seem to be due to unremoved foregrounds since this features are present in the full-sky map but not in the masked maps. On the other hand, our test detects slightly anomalous results at the scales (l,l) = (10,8) and (2,9) in the masked maps but not in the full-sky one, indicating that the foreground cleaning procedure (used to generate the full-sky map) could not only be creating false anomalies but also hiding existing ones. We also find a significant trace of an anomaly in the full-sky map at the scale (l,l) = (10,5), which is still present when we consider galactic cuts of 18.3% and 28.4%. As regards the quadrupole (l = 2), we find a coherent over-modulation over the whole celestial sphere, for all full-sky and cut-sky maps. Overall, our results seem to indicate that current CMB maps derived from WMAP data do not show significant signs of anisotropies, as measured by our angular-planar estimator. However, we have detected a curious coherence of planar modulations at angular scales of the order of the galaxy's plane, which may be an indication of residual contaminations in the full- and cut-sky maps

Memory-induced sign reversals of the spatial cross-correlation for particles in viscoelastic shear flows

International Nuclear Information System (INIS)

Sauga, Ako; Laas, Katrin; Mankin, Romi

2015-01-01

Highlights: • Cross-correlation (CC) of coordinates of particles in viscoelastic shear flows is discussed. • Expressions for CC functions subjected to both internal and external noises are presented. • Impact of internal and external noises on CC functions are compared. • Memory-induced reentrant sign reversals of the spatial cross-moment are established. - Abstract: The behavior of shear-induced cross-correlation functions between particle fluctuations along orthogonal directions in the shear plane for harmonically trapped Brownian particles in a viscoelastic shear flow is studied. A generalized Langevin equation with a power-law-type memory kernel is used to model the complex structure of the viscoelastic media. Interaction with fluctuations of environmental parameters is modeled by a multiplicative white Gaussian noise, by an internal fractional Gaussian noise, and by an additive external white noise. It is shown that the presence of a memory has a profound effect on the behavior of the cross-correlation functions. Particularly, memory-induced reentrant sign reversals of the spatial cross-moment between orthogonal random displacements of a particle are established, i.e., an increase of the memory exponent can cause the sign reversal from positive to negative, but by a further increase of the memory exponent a reentrant transition from negative to positive values appears. Similarities and differences between the behavior of the models with additive internal and external noises are considered. It is shown that additive external and internal noises cause qualitatively different dependencies of the cross-correlation functions on the time lag. The occurrence of energetic instability due to the influence of multiplicative noise is also discussed.

Substrate and coating defect planarization strategies for high-laser-fluence multilayer mirrors

International Nuclear Information System (INIS)

Stolz, Christopher J.; Wolfe, Justin E.; Mirkarimi, Paul B.; Folta, James A.; Adams, John J.; Menor, Marlon G.; Teslich, Nick E.; Soufli, Regina; Menoni, Carmen S.; Patel, Dinesh

2015-01-01

Planarizing or smoothing over nodular defects in multilayer mirrors can be accomplished by a discrete deposit-and-etch process that exploits the angle-dependent etching rate of optical materials. Typically, nodular defects limit the fluence on mirrors irradiated at 1064 nm with 10 ns pulse lengths due to geometrically- and interference-induced light intensification. Planarized hafina/silica multilayer mirrors have demonstrated > 125 J/cm 2 laser resistance for single-shot testing and 50 J/cm 2 for multi-shot testing for nodular defects originating on the substrate surface. Two planarization methods were explored: thick planarization layers on the substrate surface and planarized silica layers throughout the multilayer in which only the silica layers that are below one half of the incoming electric field value are etched. This paper also describes the impact of planarized defects that are buried within the multilayer structure compared to planarized substrate particulate defects. - Highlights: • Defect planarization significantly improves multilayer mirror laser resistance • Substrate and coating defects have both been effectively planarized • Single and multishot laser resistance improvement was demonstrated

Synaptic Correlates of Working Memory Capacity.

Science.gov (United States)

Mi, Yuanyuan; Katkov, Mikhail; Tsodyks, Misha

2017-01-18

Psychological studies indicate that human ability to keep information in readily accessible working memory is limited to four items for most people. This extremely low capacity severely limits execution of many cognitive tasks, but its neuronal underpinnings remain unclear. Here we show that in the framework of synaptic theory of working memory, capacity can be analytically estimated to scale with characteristic time of short-term synaptic depression relative to synaptic current time constant. The number of items in working memory can be regulated by external excitation, enabling the system to be tuned to the desired load and to clear the working memory of currently held items to make room for new ones. Copyright © 2017 Elsevier Inc. All rights reserved.

Bifurcation theory for finitely smooth planar autonomous differential systems

Science.gov (United States)

Han, Maoan; Sheng, Lijuan; Zhang, Xiang

2018-03-01

In this paper we establish bifurcation theory of limit cycles for planar Ck smooth autonomous differential systems, with k ∈ N. The key point is to study the smoothness of bifurcation functions which are basic and important tool on the study of Hopf bifurcation at a fine focus or a center, and of Poincaré bifurcation in a period annulus. We especially study the smoothness of the first order Melnikov function in degenerate Hopf bifurcation at an elementary center. As we know, the smoothness problem was solved for analytic and C∞ differential systems, but it was not tackled for finitely smooth differential systems. Here, we present their optimal regularity of these bifurcation functions and their asymptotic expressions in the finite smooth case.

Ultra-high-speed inversion recovery echo planar MR imaging

International Nuclear Information System (INIS)

Stehling, M.K.; Ordidge, R.J.; Coxon, R.; Chapman, B.; Houseman, A.M.; Guifoyle, D.; Blamire, A.; Gibbs, P.; Mansfield, P.

1988-01-01

Fast two-dimensional FT MR imaging techniques such as fast low-angle shot do not allow inversion recovery (IR). Rapid repetition of low-angle pulses is incompatible with a 180 0 inversion pulse. Echo planar imaging (EPI) can be applied in conjunction with IR, because after preparation of the spin system, a complete image is acquired. Data acquisition in less than 100 msec and real-time display allows interactive optimization of inversion time (4.0-9,000 msec) with little time penalty. The authors have applied IR EPI to the study of the brain, liver, and kidneys in normal volunteers and patients. Technical details are presented, and the applications of this first ultra-high-speed IR technique will be shown

Self-aligned BCB planarization method for high-frequency signal injection in a VCSEL with an integrated modulator

Science.gov (United States)

Marigo-Lombart, Ludovic; Doucet, Jean-Baptiste; Lecestre, Aurélie; Reig, Benjamin; Rousset, Bernard; Thienpont, Hugo; Panajotov, Krassimir; Almuneau, Guilhem

2016-04-01

The huge increase of datacom capacities requires lasers sources with more and more bandwidth performances. Vertical-Cavity Surface-Emitting Lasers (VCSEL) in direct modulation is a good candidate, already widely used for short communication links such as in datacenters. Recently several different approaches have been proposed to further extend the direct modulation bandwidth of these devices, by improving the VCSEL structure, or by combining the VCSEL with another high speed element such as lateral slow light modulator or transistor/laser based structure (TVCSEL). We propose to increase the modulation bandwidth by vertically integrating a continuous-wave VCSEL with a high-speed electro-modulator. This vertical structure implies multiple electrodes with sufficiently good electrical separation between the different input electrical signals. This high frequency modulation requires both good electrical insulation between metal electrodes and an optimized design of the coplanar lines. BenzoCyclobutene (BCB) thanks to its low dielectric constant, low losses, low moisture absorption and good thermal stability, is often used as insulating layer. Also, BCB planarization offers the advantages of simpler and more reliable technological process flow in such integrated VCSEL/modulator structures with important reliefs. As described by Burdeaux et al. a degree of planarization (DOP) of about 95% can be achieved by simple spin coating whatever the device thickness. In most of the cases, the BCB planarization process requires an additional photolithography step in order to open an access to the mesa surface, thus involving a tight mask alignment and resulting in a degraded planarization. In this paper, we propose a self-aligned process with improved BCB planarization by combining a hot isostatic pressing derived from nanoimprint techniques with a dry plasma etching step.

Beyond level planarity

NARCIS (Netherlands)

Angelini, P.; Da Lozzo, G.; Di Battista, G.; Frati, F.; Patrignani, M.; Rutter, I.; Hu, Y.; Nöllenburg, M.

2016-01-01

In this paper we settle the computational complexity of two open problems related to the extension of the notion of level planarity to surfaces different from the plane. Namely, we show that the problems of testing the existence of a level embedding of a level graph on the surface of the rolling

1st International Conference on Engineering and Applied Sciences Optimization : Dedicated to the Memory of Professor M.G. Karlaftis

CERN Document Server

Papadrakakis, Manolis; OPT-i

2015-01-01

The chapters which appear in this volume are selected studies presented at the First International Conference on Engineering and Applied Sciences Optimization (OPT-i), Kos, Greece, 4-6 June 2014,  and works written by friends, former colleagues and students of the late Professor M. G. Karlaftis; all in the area of optimization that he loved and published so much in himself. The subject areas represented here range from structural optimization, logistics, transportation, traffic and telecommunication networks to operational research, metaheuristics, multidisciplinary and multiphysics design optimization, etc.  This volume is dedicated to the life and the memory of Professor Matthew G. Karlaftis, who passed away a few hours before he was to give the opening speech at OPT-i. All contributions reflect the warmth and genuine friendship which he enjoyed from his associates and show how much his scientific contribution has been appreciated. He will be greatly missed and it is hoped that this volume will be receive...

Endogenous-cue prospective memory involving incremental updating of working memory: an fMRI study.

Science.gov (United States)

Halahalli, Harsha N; John, John P; Lukose, Ammu; Jain, Sanjeev; Kutty, Bindu M

2015-11-01

Prospective memory paradigms are conventionally classified on the basis of event-, time-, or activity-based intention retrieval. In the vast majority of such paradigms, intention retrieval is provoked by some kind of external event. However, prospective memory retrieval cues that prompt intention retrieval in everyday life are commonly endogenous, i.e., linked to a specific imagined retrieval context. We describe herein a novel prospective memory paradigm wherein the endogenous cue is generated by incremental updating of working memory, and investigated the hemodynamic correlates of this task. Eighteen healthy adult volunteers underwent functional magnetic resonance imaging while they performed a prospective memory task where the delayed intention was triggered by an endogenous cue generated by incremental updating of working memory. Working memory and ongoing task control conditions were also administered. The 'endogenous-cue prospective memory condition' with incremental working memory updating was associated with maximum activations in the right rostral prefrontal cortex, and additional activations in the brain regions that constitute the bilateral fronto-parietal network, central and dorsal salience networks as well as cerebellum. In the working memory control condition, maximal activations were noted in the left dorsal anterior insula. Activation of the bilateral dorsal anterior insula, a component of the central salience network, was found to be unique to this 'endogenous-cue prospective memory task' in comparison to previously reported exogenous- and endogenous-cue prospective memory tasks without incremental working memory updating. Thus, the findings of the present study highlight the important role played by the dorsal anterior insula in incremental working memory updating that is integral to our endogenous-cue prospective memory task.

Analytical investigation on cell temperature control method of planar solid oxide fuel cell

Energy Technology Data Exchange (ETDEWEB)

Inui, Y.; Ito, N.; Nakajima, T.; Urata, A. [Department of Electrical and Electronic Engineering, Toyohashi University of Technology, Tempaku-cho, Toyohashi (Japan)

2006-09-15

The solid oxide fuel cell (SOFC) has a problem in durability of the ceramics used as its cell materials because its operating temperature is very high and the cell temperature fluctuation induces thermal stress in the ceramics. The cell temperature distribution in the SOFC, therefore, should be kept as constant as possible during variable load operation through control of the average current density in the cell. Considering this fact, the authors numerically optimize the operating parameters of air utilization and the inlet gas temperature of the planar SOFC by minimizing the cell temperature shift from its nominal value and propose a new cell temperature control method that adopts these optimum operating parameters for each average current density. The effectiveness of the proposed method is very high and the temperature variation is suppressed to a very low level without lowering the single cell voltage for both the co-flow and counter-flow type cells, indicating that the proposed cell temperature control method makes variable load operation of the planar SOFC possible. (author)

Evaluation of cardiac function using multi-shot echo planar imaging

Energy Technology Data Exchange (ETDEWEB)

Nakanishi, Tadashi; Tanitame, Nobuko; Hata, Ryoichiro; Hirai, Nobuhiko; Ikeda, Midori; Ono, Chiaki; Fukuoka, Haruhito; Ito, Katsuhide [Hiroshima Univ. (Japan). School of Medicine

1998-01-01

In this study, we performed multi-shot echo planar imaging (8 shot, TR/TE/FL=55 ms/18 ms/60 degrees) and k-space segmented fast gradient echo sequence (8 views per segment, TR/TE/FL=9.9 ms/1.8 ms/30 degrees) to assess cardiac function in healthy volunteers. Transaxial sections of the entire heart were obtained with both sequences in ECG triggered, breath hold, and with a 256 x 128 matrix. Resulting temporal resolution was 55 ms for echo planar imaging, and 71 ms for k-space segmented fast gradient echo sequence, respectively. Ventricular volume and ejection fraction of both ventricles and left ventricular mass obtained with multi-shot echo planar imaging were assessed in comparison with k-space segmented fast gradient echo sequence. Measurements of left ventricular volume, ejection fraction and mass obtained with multi-shot echo planar imaging demonstrated close correlation with those obtained with k-space segmented fast gradient echo sequence. Right ventricular volumes obtained with echo planar imaging were significantly higher than those obtained with k-space segmented fast gradient echo sequence. This tendency is considered to be due to differing contrast between right ventricular myocardium and fat tissue observed with echo planar imaging relative to that observed with fast gradient echo sequence, because fat suppression is always performed in echo planar images. Multi-shot echo planar imaging can be a reliable tool for measurement of cardiac functional parameters, although wall motion analysis of the left ventricle requires higher temporal resolution and a short axial section. (K.H.)

Susceptibility of memory consolidation during lapses in recall

Science.gov (United States)

Marra, Vincenzo; O’Shea, Michael; Benjamin, Paul R.; Kemenes, Ildikó

2013-01-01

Memories that can be recalled several hours after learning may paradoxically become inaccessible for brief periods after their formation. This raises major questions about the function of these early memory lapses in the structure of memory consolidation. These questions are difficult to investigate because of the lack of information on the precise timing of lapses. However, the use of a single-trial conditioning paradigm in Lymnaea solves this problem. Here we use electrophysiological and behavioural experiments to reveal lapses in memory recall at 30 min and 2 h post conditioning. We show that only during these lapses is consolidation of long-term memory susceptible to interruption by external disturbance. These shared time points of memory lapse and susceptibility correspond to transitions between different phases of memory that have different molecular requirements. We propose that during periods of molecular transition memory recall is weakened, allowing novel sensory cues to block the consolidation of long-term memory. PMID:23481386

Susceptibility of memory consolidation during lapses in recall.

Science.gov (United States)

Marra, Vincenzo; O'Shea, Michael; Benjamin, Paul R; Kemenes, Ildikó

2013-01-01

Memories that can be recalled several hours after learning may paradoxically become inaccessible for brief periods after their formation. This raises major questions about the function of these early memory lapses in the structure of memory consolidation. These questions are difficult to investigate because of the lack of information on the precise timing of lapses. However, the use of a single-trial conditioning paradigm in Lymnaea solves this problem. Here we use electrophysiological and behavioural experiments to reveal lapses in memory recall at 30 min and 2 h post conditioning. We show that only during these lapses is consolidation of long-term memory susceptible to interruption by external disturbance. These shared time points of memory lapse and susceptibility correspond to transitions between different phases of memory that have different molecular requirements. We propose that during periods of molecular transition memory recall is weakened, allowing novel sensory cues to block the consolidation of long-term memory.

Reconstruction strategy for echo planar spectroscopy and its application to partially undersampled imaging

DEFF Research Database (Denmark)

Hanson, L G; Schaumburg, K; Paulson, O B

2000-01-01

The most commonly encountered form of echo planar spectroscopy involves oscillating gradients in one spatial dimension during readout. Data are consequently not sampled on a Cartesian grid. A fast gridding algorithm applicable to this particular situation is presented. The method is optimal, i.......e., it performs as well as the full discrete Fourier transform for band limited signals while allowing for use of the fast Fourier transform. The method is demonstrated for reconstruction of data that are partially undersampled in the time domain. The advantages of undersampling are lower hardware requirements...

Generators for finite depth subfactor planar algebras

Indian Academy of Sciences (India)

The main result of Kodiyalam and Tupurani [3] shows that a subfactor planar algebra of finite depth is singly generated with a finite presentation. If P is a subfactor planar algebra of depth k, it is shown there that a single 2k-box generates P. It is natural to ask what the smallest s is such that a single s-box generates P. While ...

Nitrogen Atom Energy Distributions in a Hollow-cathode Planar Sputtering Magnetron

International Nuclear Information System (INIS)

Ruzic, D.N.; Goeckner, M.J.; Cohen, S.A.; Wang, Zhehui

1999-01-01

Energy distributions of N atoms in a hollow-cathode planar sputtering magnetron were obtained by use of optical emission spectroscopy. A characteristic line, N I 8216.3 , well-separated from molecular nitrogen emission bands, was identified. Jansson's nonlinear spectral deconvolution method, refined by minimization of χ w ampersand sup2; , was used to obtain the optimal deconvolved spectra. These showed nitrogen atom energies from 1 eV to beyond 500 eV. Based on comparisons with VFTRIM results, we propose that the energetic N atoms are generated from N 2 + ions after these ions are accelerated through the sheath and dissociatively reflect from the cathode

A Durable Flash Memory Search Tree

OpenAIRE

Clay III, James; Wortman, Kevin

2012-01-01

We consider the task of optimizing the B-tree data structure, used extensively in operating systems and databases, for sustainable usage on multi-level flash memory. Empirical evidence shows that this new flash memory tree, or FM Tree, extends the operational lifespan of each block of flash memory by a factor of roughly 27 to 70 times, while still supporting logarithmic-time search tree operations.

Low power consumption 4-channel variable optical attenuator array based on planar lightwave circuit technique

International Nuclear Information System (INIS)

Ren Mei-Zhen; Zhang Jia-Shun; An Jun-Ming; Wang Yue; Wang Liang-Liang; Li Jian-Guang; Wu Yuan-Da; Yin XiaoJie; Hu Xiong-Wei

2017-01-01

The power consumption of a variable optical attenuator (VOA) array based on a silica planar lightwave circuit was investigated. The thermal field profile of the device was optimized using the finite-element analysis. The simulation results showed that the power consumption reduces as the depth of the heat-insulating grooves is deeper, the up-cladding is thinner, the down-cladding is thicker, and the width of the cladding ridge is narrower. The materials component and thickness of the electrodes were also optimized to guarantee the driving voltage under 5 V. The power consumption was successfully reduced to as low as 155 mW at an attenuation of 30 dB in the experiment. (paper)

Optimization of thin n-in-p planar pixel modules for the ATLAS upgrade at HL-LHC

International Nuclear Information System (INIS)

Macchiolo, A.; Beyer, J.; Rosa, A. La; Nisius, R.; Savic, N.

2017-01-01

The ATLAS experiment will undergo around the year 2025 a replacement of the tracker system in view of the high luminosity phase of the LHC (HL-LHC) with a new 5-layer pixel system. Thin planar pixel sensors are promising candidates to instrument the innermost region of the new pixel system, thanks to the reduced contribution to the material budget and their high charge collection efficiency after irradiation. The sensors of 50-150 μm thickness, interconnected to FE-I4 read-out chips, have been characterized with radioactive sources and beam tests. In particular active edge sensors have been investigated. The performance of two different versions of edge designs are compared: the first with a bias ring, and the second one where only a floating guard ring has been implemented. The hit efficiency at the edge has also been studied after irradiation at a fluence of 10 15  n eq /cm 2 . Highly segmented sensors will represent a challenge for the tracking in the forward region of the pixel system at HL-LHC. In order to reproduce the performance of 50x50 μm 2 pixels at high pseudo-rapidity values, FE-I4 compatible planar pixel sensors have been studied before and after irradiation in beam tests at high incidence angles with respect to the short pixel direction. Results on the hit efficiency in this configuration are discussed for different sensor thicknesses.

Thermal characterization of a flashing jet by planar laser-induced fluorescence

Science.gov (United States)

Vetrano, M. R.; Simonini, A.; Steelant, J.; Rambaud, P.

2013-07-01

Flash atomization can be observed when a pressurized fluid is released in an environment at lower pressure. This phenomenon plays an important role in the security management of chemical industries where liquefied gases can be accidentally released at atmosphere. In other applications, for example in propulsion systems, it can have some potential benefits as it is known to produce a fine spray with enhanced atomization. The experimental characterization of these kinds of atomization should be performed by means of non-intrusive measurement techniques since they are very sensitive to external perturbation. In this work, the planar laser-induced fluorescence technique is used to measure the liquid phase temperature of an ethanol superheated flashing jet. The feasibility of the technique is proved, measurements are taken for different superheat conditions, and an analysis of the measurement uncertainties is presented.

The default mode network and the working memory network are not anti-correlated during all phases of a working memory task.

Science.gov (United States)

Piccoli, Tommaso; Valente, Giancarlo; Linden, David E J; Re, Marta; Esposito, Fabrizio; Sack, Alexander T; Di Salle, Francesco

2015-01-01

The default mode network and the working memory network are known to be anti-correlated during sustained cognitive processing, in a load-dependent manner. We hypothesized that functional connectivity among nodes of the two networks could be dynamically modulated by task phases across time. To address the dynamic links between default mode network and the working memory network, we used a delayed visuo-spatial working memory paradigm, which allowed us to separate three different phases of working memory (encoding, maintenance, and retrieval), and analyzed the functional connectivity during each phase within and between the default mode network and the working memory network networks. We found that the two networks are anti-correlated only during the maintenance phase of working memory, i.e. when attention is focused on a memorized stimulus in the absence of external input. Conversely, during the encoding and retrieval phases, when the external stimulation is present, the default mode network is positively coupled with the working memory network, suggesting the existence of a dynamically switching of functional connectivity between "task-positive" and "task-negative" brain networks. Our results demonstrate that the well-established dichotomy of the human brain (anti-correlated networks during rest and balanced activation-deactivation during cognition) has a more nuanced organization than previously thought and engages in different patterns of correlation and anti-correlation during specific sub-phases of a cognitive task. This nuanced organization reinforces the hypothesis of a direct involvement of the default mode network in cognitive functions, as represented by a dynamic rather than static interaction with specific task-positive networks, such as the working memory network.

Context-dependent memory decay is evidence of effort minimization in motor learning: a computational study.

Science.gov (United States)

Takiyama, Ken

2015-01-01

Recent theoretical models suggest that motor learning includes at least two processes: error minimization and memory decay. While learning a novel movement, a motor memory of the movement is gradually formed to minimize the movement error between the desired and actual movements in each training trial, but the memory is slightly forgotten in each trial. The learning effects of error minimization trained with a certain movement are partially available in other non-trained movements, and this transfer of the learning effect can be reproduced by certain theoretical frameworks. Although most theoretical frameworks have assumed that a motor memory trained with a certain movement decays at the same speed during performing the trained movement as non-trained movements, a recent study reported that the motor memory decays faster during performing the trained movement than non-trained movements, i.e., the decay rate of motor memory is movement or context dependent. Although motor learning has been successfully modeled based on an optimization framework, e.g., movement error minimization, the type of optimization that can lead to context-dependent memory decay is unclear. Thus, context-dependent memory decay raises the question of what is optimized in motor learning. To reproduce context-dependent memory decay, I extend a motor primitive framework. Specifically, I introduce motor effort optimization into the framework because some previous studies have reported the existence of effort optimization in motor learning processes and no conventional motor primitive model has yet considered the optimization. Here, I analytically and numerically revealed that context-dependent decay is a result of motor effort optimization. My analyses suggest that context-dependent decay is not merely memory decay but is evidence of motor effort optimization in motor learning.

Context-dependent memory decay is evidence of effort minimization in motor learning: A computational study

Directory of Open Access Journals (Sweden)

Ken eTakiyama

2015-02-01

Full Text Available Recent theoretical models suggest that motor learning includes at least two processes: error minimization and memory decay. While learning a novel movement, a motor memory of the movement is gradually formed to minimize the movement error between the desired and actual movements in each training trial, but the memory is slightly forgotten in each trial. The learning effects of error minimization trained with a certain movement are partially available in other non-trained movements, and this transfer of the learning effect can be reproduced by certain theoretical frameworks. Although most theoretical frameworks have assumed that a motor memory trained with a certain movement decays at the same speed during performing the trained movement as non-trained movements, a recent study reported that the motor memory decays faster during performing the trained movement than non-trained movements, i.e., the decay rate of motor memory is movement or context dependent. Although motor learning has been successfully modeled based on an optimization framework, e.g., movement error minimization, the type of optimization that can lead to context-dependent memory decay is unclear. Thus, context-dependent memory decay raises the question of what is optimized in motor learning. To reproduce context-dependent memory decay, I extend a motor primitive framework. Specifically, I introduce motor effort optimization into the framework because some previous studies have reported the existence of effort optimization in motor learning processes and no conventional motor primitive model has yet considered the optimization. Here, I analytically and numerically revealed that context-dependent decay is a result of motor effort optimization. My analyses suggest that context-dependent decay is not merely memory decay but is evidence of motor effort optimization in motor learning.

Time Frame Affects Vantage Point in Episodic and Semantic Autobiographical Memory: Evidence from Response Latencies

Directory of Open Access Journals (Sweden)

Jerzy J. Karylowski

2017-04-01

Full Text Available Previous research suggests that, with the passage of time, representations of self in episodic memory become less dependent on their initial (internal vantage point and shift toward an external perspective that is normally characteristic of how other people are represented. The present experiment examined this phenomenon in both episodic and semantic autobiographical memory using latency of self-judgments as a measure of accessibility of the internal vs. the external perspective. Results confirmed that in the case of representations of the self retrieved from recent autobiographical memories, trait-judgments regarding unobservable self-aspects (internal perspective were faster than trait judgments regarding observable self-aspects (external perspective. Yet, in the case of self-representations retrieved from memories of a more distant past, judgments regarding observable self-aspects were faster. Those results occurred for both self-representations retrieved from episodic memory and for representations retrieved from the semantic memory. In addition, regardless of the effect of time, greater accessibility of unobservable (vs. observable self-aspects was associated with the episodic rather than semantic autobiographical memory. Those results were modified by neither declared trait’s self-descriptiveness (yes vs. no responses nor by its desirability (highly desirable vs. moderately desirable traits. Implications for compatibility between how self and others are represented and for the role of self in social perception are discussed.

Time Frame Affects Vantage Point in Episodic and Semantic Autobiographical Memory: Evidence from Response Latencies.

Science.gov (United States)

Karylowski, Jerzy J; Mrozinski, Blazej

2017-01-01

Previous research suggests that, with the passage of time, representations of self in episodic memory become less dependent on their initial (internal) vantage point and shift toward an external perspective that is normally characteristic of how other people are represented. The present experiment examined this phenomenon in both episodic and semantic autobiographical memory using latency of self-judgments as a measure of accessibility of the internal vs. the external perspective. Results confirmed that in the case of representations of the self retrieved from recent autobiographical memories, trait-judgments regarding unobservable self-aspects (internal perspective) were faster than trait judgments regarding observable self-aspects (external perspective). Yet, in the case of self-representations retrieved from memories of a more distant past, judgments regarding observable self-aspects were faster. Those results occurred for both self-representations retrieved from episodic memory and for representations retrieved from the semantic memory. In addition, regardless of the effect of time, greater accessibility of unobservable (vs. observable) self-aspects was associated with the episodic rather than semantic autobiographical memory. Those results were modified by neither declared trait's self-descriptiveness ( yes vs. no responses) nor by its desirability (highly desirable vs. moderately desirable traits). Implications for compatibility between how self and others are represented and for the role of self in social perception are discussed.

Nonlinear Saturation Amplitude in Classical Planar Richtmyer–Meshkov Instability

International Nuclear Information System (INIS)

Liu Wan-Hai; Jiang Hong-Bin; Ma Wen-Fang; Wang Xiang

2016-01-01

The classical planar Richtmyer–Meshkov instability (RMI) at a fluid interface supported by a constant pressure is investigated by a formal perturbation expansion up to the third order, and then according to definition of nonlinear saturation amplitude (NSA) in Rayleigh–Taylor instability (RTI), the NSA in planar RMI is obtained explicitly. It is found that the NSA in planar RMI is affected by the initial perturbation wavelength and the initial amplitude of the interface, while the effect of the initial amplitude of the interface on the NSA is less than that of the initial perturbation wavelength. Without marginal influence of the initial amplitude, the NSA increases linearly with wavelength. The NSA normalized by the wavelength in planar RMI is about 0.11, larger than that corresponding to RTI. (paper)

Dreaming and offline memory consolidation.

Science.gov (United States)

Wamsley, Erin J

2014-03-01

Converging evidence suggests that dreaming is influenced by the consolidation of memory during sleep. Following encoding, recently formed memory traces are gradually stabilized and reorganized into a more permanent form of long-term storage. Sleep provides an optimal neurophysiological state to facilitate this process, allowing memory networks to be repeatedly reactivated in the absence of new sensory input. The process of memory reactivation and consolidation in the sleeping brain appears to influence conscious experience during sleep, contributing to dream content recalled on awakening. This article outlines several lines of evidence in support of this hypothesis, and responds to some common objections.

The peeling process of infinite Boltzmann planar maps

DEFF Research Database (Denmark)

Budd, Timothy George

2016-01-01

criterion has a very simple interpretation. The finite random planar maps under consideration were recently proved to possess a well-defined local limit known as the infinite Boltzmann planar map (IBPM). Inspired by recent work of Curien and Le Gall, we show that the peeling process on the IBPM can...

Novel effect of interplay of internal and external noise on the dynamics of calcium oscillations

International Nuclear Information System (INIS)

Li Hongying; Ma Juan

2010-01-01

Graphical abstract: When the external noise is small (D ≤ 0.8), R goes through a maximum at an optimal system size V, indicating the occurring of internal-noise stochastic resonance (INSR), and the curves become higher with the increases of D, which shows that INSR can be enhanced by the external noise in a certain range of external noise intensity ((D ≤ 0.8). If D > 0.8, R monotonically increases and the peak disappears. When D increases further, the R curve becomes lower. Research highlights: → External noise coherence resonance (ENCR) can be suppressed by internal noise. → Internal noise stochastic resonance (INSR) can be enhanced by external noise. → When INSR occurs, the optimal system size can be regulated by the external noise. - Abstract: Using a mesoscopic stochastic model, the effect of interplay of external and internal noise on the dynamics of calcium oscillations was studied. When the system was tuned near a Hopf bifurcation point and driven by external noise or internal noise only, the existence of external noise coherence resonance (ENCR) or internal-noise stochastic resonance (INSR) was found, respectively. When both of the noises were considered, it was found that ENCR could be suppressed by internal noise, while INSR could be enhanced by external noise in a certain range of external noise intensity. It was also interesting to note that the optimal system size can be regulated by the external noise when the INSR occurs. The cell system may adapt to adjust the optimal size according to the external noise, indicating some kind of self-tuning mechanism involved in stochastic calcium dynamics.

Planar dynamical systems selected classical problems

CERN Document Server

Liu, Yirong; Huang, Wentao

2014-01-01

This book presents in an elementary way the recent significant developments in the qualitative theory of planar dynamical systems. The subjects are covered as follows: the studies of center and isochronous center problems, multiple Hopf bifurcations and local and global bifurcations of the equivariant planar vector fields which concern with Hilbert's 16th problem. This book is intended for graduate students, post-doctors and researchers in the area of theories and applications of dynamical systems. For all engineers who are interested the theory of dynamical systems, it is also a reasona

Open-Source-Based 3D Printing of Thin Silica Gel Layers in Planar Chromatography.

Science.gov (United States)

Fichou, Dimitri; Morlock, Gertrud E

2017-02-07

On the basis of open-source packages, 3D printing of thin silica gel layers is demonstrated as proof-of-principle for use in planar chromatography. A slurry doser was designed to replace the plastic extruder of an open-source Prusa i3 printer. The optimal parameters for 3D printing of layers were studied, and the planar chromatographic separations on these printed layers were successfully demonstrated with a mixture of dyes. The layer printing process was fast. For printing a 0.2 mm layer on a 10 cm × 10 cm format, it took less than 5 min. It was affordable, i.e., the running costs for producing such a plate were less than 0.25 Euro and the investment costs for the modified hardware were 630 Euro. This approach demonstrated not only the potential of the 3D printing environment in planar chromatography but also opened new avenues and new perspectives for tailor-made plates, not only with regard to layer materials and their combinations (gradient plates) but also with regard to different layer shapes and patterns. As such an example, separations on a printed plane layer were compared with those obtained from a printed channeled layer. For the latter, 40 channels were printed in parallel on a 10 cm × 10 cm format for the separation of 40 samples. For producing such a channeled plate, the running costs were below 0.04 Euro and the printing process took only 2 min. All modifications of the device and software were released open-source to encourage reuse and improvements and to stimulate the users to contribute to this technology. By this proof-of-principle, another asset was demonstrated to be integrated into the Office Chromatography concept, in which all relevant steps for online miniaturized planar chromatography are performed by a single device.

Working Memory and Behavioural Problems in Relation to Malay Writing of Primary School Children

Science.gov (United States)

Ling, Teo-Sieak; Jiar, Yeo-Kee

2017-01-01

Deficit in working memory is common among young children across multiple abilities. Teachers have pointed to poor memory as one contributing factor to inattentiveness and short attention spans as well as some behavioural problems among students. This study aimed to explore the relationship among working memory, externalizing and internalizing…

An interleaved structure for a high-voltage planar transformer for a Travelling-wave Tube

DEFF Research Database (Denmark)

Zhao, Bin; Wang, Gang; Hurley, William G.

2016-01-01

Fully interleaved structure can significantly reduce leakage inductance in transformers, However， it is hard to apply them into high-voltage applications due to the electric insulation. In this paper, a partially interleaved structure that is suitable for high-voltage high frequency applications...... is proposed to reduce leakage inductance and the insulation’s thickness is adjusted to optimize the electric isolation. In addition, the resistance and parasitic capacitance are investigated. With this method, a planar transformer used for a Travelling-Wave Tube Amplifier (TWTA) is designed. Calculations...

The Implementation of Marginal External Cost Pricing in Road Transport

OpenAIRE

Verhoef, Erik T.

1998-01-01

This paper discusses a number of issues that will become increasingly important nowthat the concept of marginal external cost pricing becomes more likely to be implementedas a policy strategy in transport in reality. The first part of the paper deals with thelong-run efficiency of marginal external cost pricing. It is shown that such prices notonly optimize short-run mobility, given the shape and position of the relevant demandand cost curves, but even more importantly, also optimally affect ...

Current in heavy-current planar diode with discrete emission surface

International Nuclear Information System (INIS)

Belomyttsev, S.Ya.; Korovin, S.D.; Pegel', I.V

1999-01-01

Dependence of current in a high-current planar diode on the size of emission centres was studied. Essential effect of emission surface microstructure on the current value in the planar diode was demonstrated. It was determined that if the distance between the emitter essentially exceeded their size then current dependence on the ratio of size to the value of the diode gap was an exponential function with 3/2 index. Current dependence on voltage obeyed the exponential law with 3/2 index up to higher voltage values in the planar diode with discrete emission surface in contrast to the case of a planar diode with homogeneous emission surface [ru

Identification of a Typical CSTR Using Optimal Focused Time Lagged Recurrent Neural Network Model with Gamma Memory Filter

OpenAIRE

Naikwad, S. N.; Dudul, S. V.

2009-01-01

A focused time lagged recurrent neural network (FTLR NN) with gamma memory filter is designed to learn the subtle complex dynamics of a typical CSTR process. Continuous stirred tank reactor exhibits complex nonlinear operations where reaction is exothermic. It is noticed from literature review that process control of CSTR using neuro-fuzzy systems was attempted by many, but optimal neural network model for identification of CSTR process is not yet available. As CSTR process includes tempora...

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

OpenAIRE

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

2016-01-01

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

Entanglement and optimal strings of qubits for memory channels

International Nuclear Information System (INIS)

Karimipour, V.; Memarzadeh, L.

2006-01-01

We investigate the problem of enhancement of mutual information by encoding classical data into entangled input states of arbitrary length and show that while there is a threshold memory or correlation parameter beyond which entangled states outperform the separable states, resulting in a higher mutual information, this memory threshold increases toward unity as the length of the string increases. These observations imply that encoding classical data into entangled states may not enhance the classical capacity of quantum channels

Optimizing main-memory join on modern hardware

NARCIS (Netherlands)

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

2002-01-01

textabstractIn the past decade, the exponential growth in commodity CPUs speed has far outpaced advances in memory latency. A second trend is that CPU performance advances are not only brought by increased clock rate, but also by increasing parallelism inside the CPU. Current database systems have

Optimizing main-memory join on modern hardware

NARCIS (Netherlands)

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

1999-01-01

textabstractIn the past decade, the exponential growth in commodity CPUs speed has far outpaced advances in memory latency. A second trend is that CPU performance advances are not only brought by increased clock rate, but also by increasing parallelism inside the CPU. Current database systems have

Elliptic annular Josephson tunnel junctions in an external magnetic field: the statics

DEFF Research Database (Denmark)

Monaco, Roberto; Granata, Carmine; Vettoliere, Antonio

2015-01-01

We have investigated the static properties of one-dimensional planar Josephson tunnel junctions (JTJs) in the most general case of elliptic annuli. We have analyzed the dependence of the critical current in the presence of an external magnetic field applied either in the junction plane...... symmetric electrodes a transverse magnetic field is equivalent to an in-plane field applied in the direction of the current flow. Varying the ellipse eccentricity we reproduce all known results for linear and ring-shaped JTJs. Experimental data on high-quality Nb/Al-AlOx/Nb elliptic annular junctions...

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

OpenAIRE

Manegold, Stefan; Boncz, Peter; Kersten, Martin

2000-01-01

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

Advertising in Markets with Consumption Externalities

OpenAIRE

Whelan, Adele

2014-01-01

This paper extends the entry deterrence literature by examining coordinating advertising in markets with consumption externalities using a stochastic success function. Optimal advertising and pricing strategies are analysed when an incumbent firm faces a challenger with a product of equal quality. I show that strategic entry deterrence using advertising is possible and optimal entry deterrence involves strategic pre-commitment to over-investment relative to the non-strategic simultaneous adve...

Hydrogenated arsenenes as planar magnet and Dirac material

Energy Technology Data Exchange (ETDEWEB)

Zhang, Shengli; Cai, Bo; Zeng, Haibo, E-mail: Huziyu@csrc.ac.cn, E-mail: zeng.haibo@njust.edu.cn [Institute of Optoelectronics and Nanomaterials, Herbert Gleiter Institute of Nanoscience, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); Hu, Yonghong [Institute of Optoelectronics and Nanomaterials, Herbert Gleiter Institute of Nanoscience, College of Materials Science and Engineering, Nanjing University of Science and Technology, Nanjing 210094 (China); School of Nuclear Technology and Chemistry and Biology, Hubei University of Science and Technology, Xianning 437100 (China); Hu, Ziyu, E-mail: Huziyu@csrc.ac.cn, E-mail: zeng.haibo@njust.edu.cn [Beijing Computational Science Research Center, Beijing 100084 (China)

2015-07-13

Arsenene and antimonene are predicted to have 2.49 and 2.28 eV band gaps, which have aroused intense interest in the two-dimensional (2D) semiconductors for nanoelectronic and optoelectronic devices. Here, the hydrogenated arsenenes are reported to be planar magnet and 2D Dirac materials based on comprehensive first-principles calculations. The semi-hydrogenated (SH) arsenene is found to be a quasi-planar magnet, while the fully hydrogenated (FH) arsenene is a planar Dirac material. The buckling height of pristine arsenene is greatly decreased by the hydrogenation, resulting in a planar and relatively low-mass-density sheet. The electronic structures of arsenene are also evidently altered after hydrogenating from wide-band-gap semiconductor to metallic material for SH arsenene, and then to Dirac material for FH arsenene. The SH arsenene has an obvious magnetism, mainly contributed by the p orbital of the unsaturated As atom. Such magnetic and Dirac materials modified by hydrogenation of arsenene may have potential applications in future optoelectronic and spintronic devices.

Hydrogenated arsenenes as planar magnet and Dirac material

International Nuclear Information System (INIS)

Zhang, Shengli; Cai, Bo; Zeng, Haibo; Hu, Yonghong; Hu, Ziyu

2015-01-01

Arsenene and antimonene are predicted to have 2.49 and 2.28 eV band gaps, which have aroused intense interest in the two-dimensional (2D) semiconductors for nanoelectronic and optoelectronic devices. Here, the hydrogenated arsenenes are reported to be planar magnet and 2D Dirac materials based on comprehensive first-principles calculations. The semi-hydrogenated (SH) arsenene is found to be a quasi-planar magnet, while the fully hydrogenated (FH) arsenene is a planar Dirac material. The buckling height of pristine arsenene is greatly decreased by the hydrogenation, resulting in a planar and relatively low-mass-density sheet. The electronic structures of arsenene are also evidently altered after hydrogenating from wide-band-gap semiconductor to metallic material for SH arsenene, and then to Dirac material for FH arsenene. The SH arsenene has an obvious magnetism, mainly contributed by the p orbital of the unsaturated As atom. Such magnetic and Dirac materials modified by hydrogenation of arsenene may have potential applications in future optoelectronic and spintronic devices

Hydrogenated arsenenes as planar magnet and Dirac material

Science.gov (United States)

Zhang, Shengli; Hu, Yonghong; Hu, Ziyu; Cai, Bo; Zeng, Haibo

2015-07-01

Arsenene and antimonene are predicted to have 2.49 and 2.28 eV band gaps, which have aroused intense interest in the two-dimensional (2D) semiconductors for nanoelectronic and optoelectronic devices. Here, the hydrogenated arsenenes are reported to be planar magnet and 2D Dirac materials based on comprehensive first-principles calculations. The semi-hydrogenated (SH) arsenene is found to be a quasi-planar magnet, while the fully hydrogenated (FH) arsenene is a planar Dirac material. The buckling height of pristine arsenene is greatly decreased by the hydrogenation, resulting in a planar and relatively low-mass-density sheet. The electronic structures of arsenene are also evidently altered after hydrogenating from wide-band-gap semiconductor to metallic material for SH arsenene, and then to Dirac material for FH arsenene. The SH arsenene has an obvious magnetism, mainly contributed by the p orbital of the unsaturated As atom. Such magnetic and Dirac materials modified by hydrogenation of arsenene may have potential applications in future optoelectronic and spintronic devices.

Quality assurance for high dose rate brachytherapy treatment planning optimization: using a simple optimization to verify a complex optimization

International Nuclear Information System (INIS)

Deufel, Christopher L; Furutani, Keith M

2014-01-01

As dose optimization for high dose rate brachytherapy becomes more complex, it becomes increasingly important to have a means of verifying that optimization results are reasonable. A method is presented for using a simple optimization as quality assurance for the more complex optimization algorithms typically found in commercial brachytherapy treatment planning systems. Quality assurance tests may be performed during commissioning, at regular intervals, and/or on a patient specific basis. A simple optimization method is provided that optimizes conformal target coverage using an exact, variance-based, algebraic approach. Metrics such as dose volume histogram, conformality index, and total reference air kerma agree closely between simple and complex optimizations for breast, cervix, prostate, and planar applicators. The simple optimization is shown to be a sensitive measure for identifying failures in a commercial treatment planning system that are possibly due to operator error or weaknesses in planning system optimization algorithms. Results from the simple optimization are surprisingly similar to the results from a more complex, commercial optimization for several clinical applications. This suggests that there are only modest gains to be made from making brachytherapy optimization more complex. The improvements expected from sophisticated linear optimizations, such as PARETO methods, will largely be in making systems more user friendly and efficient, rather than in finding dramatically better source strength distributions. (paper)

The number of colorings of planar graphs with no separating triangles

DEFF Research Database (Denmark)

Thomassen, Carsten

2017-01-01

A classical result of Birkhoff and Lewis implies that every planar graph with . n vertices has at least . 152n-1 distinct 5-vertex-colorings. Equality holds for planar triangulations with . n-4 separating triangles. We show that, if a planar graph has no separating triangle, then it has at least ...

Planar waveguides and other confined geometries theory, technology, production, and novel applications

CERN Document Server

2015-01-01

This book provides a comprehensive overview of the theoretical concepts and experimental applications of planar waveguides and other confined geometries, such as optical fibres. Covering a broad array of advanced topics, it begins with a sophisticated discussion of planar waveguide theory, and covers subjects including efficient production of planar waveguides, materials selection, nonlinear effects, and applications including species analytics down to single-molecule identification, and thermo-optical switching using planar waveguides. Written by specialists in the techniques and applications covered, this book will be a useful resource for advanced graduate students and researchers studying planar waveguides and optical fibers.

Determination of crystallographic and macroscopic orientation of planar structures in TEM

DEFF Research Database (Denmark)

Huang, X.; Liu, Q.

1998-01-01

With the aid of a double-tilt holder in a transmission electron microscope (TEM), simple methods are described for determination of the crystallographic orientation of a planar structure and for calculation of the macroscopic orientation of the planar structure. The correlation between a planar...... structure and a crystallographic plane can be found by comparing the differences in their trace directions on the projection plane and inclination angles with respect to that plane. The angles between the traces of planar structures and the sample axis measured from the TEM micrographs, which have been...

Optimal Point-to-Point Trajectory Tracking of Redundant Manipulators using Generalized Pattern Search

Directory of Open Access Journals (Sweden)

Thi Rein Myo

2008-11-01

Full Text Available Optimal point-to-point trajectory planning for planar redundant manipulator is considered in this study. The main objective is to minimize the sum of the position error of the end-effector at each intermediate point along the trajectory so that the end-effector can track the prescribed trajectory accurately. An algorithm combining Genetic Algorithm and Pattern Search as a Generalized Pattern Search GPS is introduced to design the optimal trajectory. To verify the proposed algorithm, simulations for a 3-D-O-F planar manipulator with different end-effector trajectories have been carried out. A comparison between the Genetic Algorithm and the Generalized Pattern Search shows that The GPS gives excellent tracking performance.

Manufacturing of planar ceramic interconnects

Energy Technology Data Exchange (ETDEWEB)

Armstrong, B.L.; Coffey, G.W.; Meinhardt, K.D.; Armstrong, T.R. [Pacific Northwest National Lab., Richland, WA (United States)

1996-12-31

The fabrication of ceramic interconnects for solid oxide fuel cells (SOFC) and separator plates for electrochemical separation devices has been a perennial challenge facing developers. Electrochemical vapor deposition (EVD), plasma spraying, pressing, tape casting and tape calendering are processes that are typically utilized to fabricate separator plates or interconnects for the various SOFC designs and electrochemical separation devices. For sake of brevity and the selection of a planar fuel cell or gas separation device design, pressing will be the only fabrication technique discussed here. This paper reports on the effect of the characteristics of two doped lanthanum manganite powders used in the initial studies as a planar porous separator for a fuel cell cathode and as a dense interconnect for an oxygen generator.

Backscattering study and theoretical investigation of planar channeling processes. I. Experimental results

International Nuclear Information System (INIS)

Abel, F.; Amsel, G.; Bruneaux, M.; Cohen, C.; L'Hoir, A.

1975-01-01

Backscattering experiments in planar channeling have been performed on iron single crystals with 1.9-MeV 4 He beams; these conditions having been chosen for optimal study of the structure of the spectra. Both for the (110) and (100) planes five equally spaced yield maxima are clearly resolved, the maxima damping out at lower energies. Spectra were also registered at various angles of incidence phi 0 with respect to the planes. Yield maxima are observed up to values of phi 0 twice the half-width at half-minimum psi 1 / 2 of an angular scan across the plane psi 1 / 2 =18' for the (110) plane. Except for the first two peaks, these maxima have the same spacing as in the aligned spectrum. They appear to be due to particles belonging to a well-defined transverse energy interval. The mean stopping power for these particles is close to the random stopping power and the mean half-wavelength of their oscillating trajectories in the planar channels calculated from the results is lambda=380 A for the (110) plane and lambda=320 A for the (100) plane. For phi 0 >1.2psi 1 / 2 , the yield on the first maximum is greater than the random yield, reaching approx.1.6 times the latter for 1.4psi 1 / 2 0 1 / 2 . The shoulder effect in the angular scans, as observed for various depths, is clearly related to the yield maxima and hence depends strongly on the position and width of the depth interval chosen. The meaning and validity of the assumption of statistical equilibrium for planar channeled particles are discussed in light of the results

High spatial resolution infrared camera as ISS external experiment

Science.gov (United States)

Eckehard, Lorenz; Frerker, Hap; Fitch, Robert Alan

High spatial resolution infrared camera as ISS external experiment for monitoring global climate changes uses ISS internal and external resources (eg. data storage). The optical experiment will consist of an infrared camera for monitoring global climate changes from the ISS. This technology was evaluated by the German small satellite mission BIRD and further developed in different ESA projects. Compared to BIRD the presended instrument uses proven sensor advanced technologies (ISS external) and ISS on board processing and storage capabili-ties (internal). The instrument will be equipped with a serial interfaces for TM/TC and several relay commands for the power supply. For data processing and storage a mass memory is re-quired. The access to actual attitude data is highly desired to produce geo referenced maps-if possible by an on board processing.

Three-dimensional crossbar interconnection using planar-integrated free-space optics and digital mirror-device

Science.gov (United States)

Lohmann, U.; Jahns, J.; Limmer, S.; Fey, D.

2011-01-01

We consider the implementation of a dynamic crossbar interconnect using planar-integrated free-space optics (PIFSO) and a digital mirror-device™ (DMD). Because of the 3D nature of free-space optics, this approach is able to solve geometrical problems with crossings of the signal paths that occur in waveguide optical and electrical interconnection, especially for large number of connections. The DMD device allows one to route the signals dynamically. Due to the large number of individual mirror elements in the DMD, different optical path configurations are possible, thus offering the chance for optimizing the network configuration. The optimization is achieved by using an evolutionary algorithm for finding best values for a skewless parallel interconnection. Here, we present results and experimental examples for the use of the PIFSO/DMD-setup.

Acute exercise improves motor memory

DEFF Research Database (Denmark)

Skriver, Kasper Christen; Roig, Marc; Lundbye-Jensen, Jesper

2014-01-01

We have recently shown that a single bout of acute cardiovascular exercise improves motor skill learning through an optimization of long-term motor memory. Here we expand this previous finding, to explore potential exercise-related biomarkers and their association with measures of motor memory...... practice whereas lactate correlated with better retention 1 hour as well as 24 hours and 7 days after practice. Thus, improvements in motor skill acquisition and retention induced by acute cardiovascular exercise are associated with increased concentrations of biomarkers involved in memory and learning...... processes. More mechanistic studies are required to elucidate the specific role of each biomarker in the formation of motor memory....

The simple method to co-register planar image with photograph

International Nuclear Information System (INIS)

Jang, Sung June; Kim, Seok Ki; Kang, Keon Wook

2005-01-01

Generally scintigraphic image presents the highly specific functional information. Sometimes, there can be limited information of patients anatomical landmark required to identify the lesion in planar nuclear medicine image. In this study, we applied the simple fusion method of planar scintigraphy and plain photography and validated the techniques with our own software. We used three fiducial marks which were comprised with Tc-99m. We obtained planar image with single head gamma camera (ARGUS ADAC laboratory, USA) and photograph using a general digital camera (CANON JAPAN). The coordinates of three marks were obtained in photograph and planar scintigraphy image. Based on these points, we took affine transformation and then fused these two images. To evaluate the precision, we compared with different depth. To find out the depth of lesion, the images were acquired in different angles and we compared the real depth and the geometrically calculated depth. At the same depth with mark, the each discordance was less than 1 mm. When the photograph were taken at the distance with 1 m and 2 m, the point 30 cm off the center were discordant in 5 mm and 2 mm each. We used this method in the localization of the remnant thyroid tissue on I-131 whole body scan with photo image. The simple method to co-register planar image with photography was reliable and easy to use. By this method, we could localize the lesion on the planar scintigraphy more accurately with other planar images (i.e. photograph) and predict the depth of the lesion without tomographic image

Sparse Distributed Memory: understanding the speed and robustness of expert memory

Directory of Open Access Journals (Sweden)

Marcelo Salhab Brogliato

2014-04-01

Full Text Available How can experts, sometimes in exacting detail, almost immediately and very precisely recall memory items from a vast repertoire? The problem in which we will be interested concerns models of theoretical neuroscience that could explain the speed and robustness of an expert's recollection. The approach is based on Sparse Distributed Memory, which has been shown to be plausible, both in a neuroscientific and in a psychological manner, in a number of ways. A crucial characteristic concerns the limits of human recollection, the `tip-of-tongue' memory event--which is found at a non-linearity in the model. We expand the theoretical framework, deriving an optimization formula to solve to this non-linearity. Numerical results demonstrate how the higher frequency of rehearsal, through work or study, immediately increases the robustness and speed associated with expert memory.

PIYAS-Proceeding to Intelligent Service Oriented Memory Allocation for Flash Based Data Centric Sensor Devices in Wireless Sensor Networks

Directory of Open Access Journals (Sweden)

Sanam Shahla Rizvi

2009-12-01

Full Text Available Flash memory has become a more widespread storage medium for modern wireless devices because of its effective characteristics like non-volatility, small size, light weight, fast access speed, shock resistance, high reliability and low power consumption. Sensor nodes are highly resource constrained in terms of limited processing speed, runtime memory, persistent storage, communication bandwidth and finite energy. Therefore, for wireless sensor networks supporting sense, store, merge and send schemes, an efficient and reliable file system is highly required with consideration of sensor node constraints. In this paper, we propose a novel log structured external NAND flash memory based file system, called Proceeding to Intelligent service oriented memorY Allocation for flash based data centric Sensor devices in wireless sensor networks (PIYAS. This is the extended version of our previously proposed PIYA [1]. The main goals of the PIYAS scheme are to achieve instant mounting and reduced SRAM space by keeping memory mapping information to a very low size of and to provide high query response throughput by allocation of memory to the sensor data by network business rules. The scheme intelligently samples and stores the raw data and provides high in-network data availability by keeping the aggregate data for a longer period of time than any other scheme has done before. We propose effective garbage collection and wear-leveling schemes as well. The experimental results show that PIYAS is an optimized memory management scheme allowing high performance for wireless sensor networks.

PIYAS-proceeding to intelligent service oriented memory allocation for flash based data centric sensor devices in wireless sensor networks.

Science.gov (United States)

Rizvi, Sanam Shahla; Chung, Tae-Sun

2010-01-01

Flash memory has become a more widespread storage medium for modern wireless devices because of its effective characteristics like non-volatility, small size, light weight, fast access speed, shock resistance, high reliability and low power consumption. Sensor nodes are highly resource constrained in terms of limited processing speed, runtime memory, persistent storage, communication bandwidth and finite energy. Therefore, for wireless sensor networks supporting sense, store, merge and send schemes, an efficient and reliable file system is highly required with consideration of sensor node constraints. In this paper, we propose a novel log structured external NAND flash memory based file system, called Proceeding to Intelligent service oriented memorY Allocation for flash based data centric Sensor devices in wireless sensor networks (PIYAS). This is the extended version of our previously proposed PIYA [1]. The main goals of the PIYAS scheme are to achieve instant mounting and reduced SRAM space by keeping memory mapping information to a very low size of and to provide high query response throughput by allocation of memory to the sensor data by network business rules. The scheme intelligently samples and stores the raw data and provides high in-network data availability by keeping the aggregate data for a longer period of time than any other scheme has done before. We propose effective garbage collection and wear-leveling schemes as well. The experimental results show that PIYAS is an optimized memory management scheme allowing high performance for wireless sensor networks.

Autonomy and coordination: Controlling external influences on decision making

NARCIS (Netherlands)

Vecht, B. van der; Dignum, F.; Meyer, J.J.C.

2009-01-01

In order to achieve optimal results, an agent's way of decision making might need to change according to the circumstances. One of the aspects an agent can adapt is the way it processes external events. Therewith it controls to what extend it is being influenced by external factors. We argue that

Fast Response, Open-Celled Porous, Shape Memory Effect Actuators with Integrated Attachments

Science.gov (United States)

Jardine, Andrew Peter (Inventor)

2015-01-01

This invention relates to the exploitation of porous foam articles exhibiting the Shape Memory Effect as actuators. Each foam article is composed of a plurality of geometric shapes, such that some geometric shapes can fit snugly into or around rigid mating connectors that attach the Shape Memory foam article intimately into the load path between a static structure and a moveable structure. The foam is open-celled, composed of a plurality of interconnected struts whose mean diameter can vary from approximately 50 to 500 microns. Gases and fluids flowing through the foam transfer heat rapidly with the struts, providing rapid Shape Memory Effect transformations. Embodiments of porous foam articles as torsional actuators and approximately planar structures are disposed. Simple, integral connection systems exploiting the ability to supply large loads to a structure, and that can also supply hot and cold gases and fluids to effect rapid actuation are also disposed.

The external-internal loop of interference: two types of attention and their influence on the learning abilities of mice.

Science.gov (United States)

Sauce, Bruno; Wass, Christopher; Smith, Andrew; Kwan, Stephanie; Matzel, Louis D

2014-12-01

Attention is a component of the working memory system, and is responsible for protecting task-relevant information from interference. Cognitive performance (particularly outside of the laboratory) is often plagued by interference, and the source of this interference, either external or internal, might influence the expression of individual differences in attentional ability. By definition, external attention (also described as "selective attention") protects working memory against sensorial distractors of all kinds, while internal attention (also called "inhibition") protects working memory against emotional impulses, irrelevant information from memory, and automatically-generated responses. At present, it is unclear if these two types of attention are expressed independently in non-human animals, and how they might differentially impact performance on other cognitive processes, such as learning. By using a diverse battery of four attention tests (with varying levels of internal and external sources of interference), here we aimed both to explore this issue, and to obtain a robust and general (less task-specific) measure of attention in mice. Exploratory factor analyses revealed two factors (external and internal attention) that in total, accounted for 73% of the variance in attentional performance. Confirmatory factor analyses found an excellent fit with the data of the model of attention that assumed an external and internal distinction (with a resulting correlation of 0.43). In contrast, a model of attention that assumed one source of variance (i.e., "general attention") exhibited a poor fit with the data. Regarding the relationship between attention and learning, higher resistance against external sources of interference promoted better new learning, but tended to impair performance when cognitive flexibility was required, such as during the reversal of a previously instantiated response. The present results suggest that there can be (at least) two types of

Negatively correlated local and global stock externalities: tax or subsidy?

International Nuclear Information System (INIS)

Zili Yang

2006-01-01

Fossil fuel combustion generates both CO 2 and SO 2 . CO 2 is the most important greenhouse gas; SO 2 can cause serious local pollution. But it can alleviate the potential global warming because of negative radiative forcing. Such a phenomenon can be characterized as negatively correlated local and global stock externalities. In this paper, we set up an optimal control problem of negatively correlated local and global stock externality provision. The efficiency conditions for this problem are derived. These conditions modify the Samuelson rules for optimal provision of externalities. In addition, we examine several policy related scenarios of negatively correlated local and global stock externality provisions. Finally, we discuss policy implications and limitation of the theoretical results derived in this paper. We also indicate applications of the theoretical results here to empirical research, particularly to economic analysis of multiple-gas issues in climate change. (Author)

Design and measurements of the double layer planar motor

NARCIS (Netherlands)

Rovers, J.M.M.; Jansen, J.W.; Lomonova, E.

2013-01-01

Moving-magnet magnetically levitated planar motors are considered for use as a wafer stage in the semiconductor lithographic industry. This puts high requirements on the accuracy and the dissipated power and cooling performance of such motors. A novel planar motor topology is developed, which

Sensory memory of illusory depth in structure-from-motion.

Science.gov (United States)

Pastukhov, Alexander; Lissner, Anna; Füllekrug, Jana; Braun, Jochen

2014-01-01

When multistable displays (stimuli consistent with two or more equally plausible perceptual interpretations) are presented intermittently, their perceptions are stabilized by sensory memory. Independent memory traces are generated not only for different types of multistable displays (Maier, Wilke, Logothetis, & Leopold, Current Biology 13:1076-1085, 2003), but also for different ambiguous features of binocular rivalry (Pearson & Clifford, Journal of Vision 4:196-202, 2004). In the present study, we examined whether a similar independence of sensory memories is observed in structure-from-motion (SFM), a multistable display with two ambiguous properties. In SFM, a 2-D planar motion creates a vivid impression of a rotating 3-D volume. Both the illusory rotation and illusory depth (i.e., how close parts of an object appear to the observer) of an SFM object are ambiguous. We dissociated the sensory memories of these two ambiguous properties by using an intermittent presentation in combination with a forced-ambiguous-switch paradigm (Pastukhov, Vonau, & Braun, PLoS ONE 7:e37734, 2012). We demonstrated that the illusory depth of SFM generates a sensory memory trace that is independent from that of illusory rotation. Despite this independence, the specificities levels of the sensory memories were identical for illusory depth and illusory rotation. The history effect was weakened by a change in the volumetric property of a shape (whether it was a hollow band or a filled drum volume), but not by changes in color or size. We discuss how these new results constrain models of sensory memory and SFM processing.

Storing information in-the-world: Metacognition and cognitive offloading in a short-term memory task.

Science.gov (United States)

Risko, Evan F; Dunn, Timothy L

2015-11-01

We often store to-be-remembered information externally (e.g., written down on a piece of paper) rather than internally. In the present investigation, we examine factors that influence the decision to store information in-the-world versus in-the-head using a variant of a traditional short term memory task. In Experiments 1a and 1b participants were presented with to-be-remembered items and either had to rely solely on internal memory or had the option to write down the presented information. In Experiments 2a and 2b participants were presented with the same stimuli but made metacognitive judgments about their predicted performance and effort expenditure. The spontaneous use of external storage was related both to the number of items to be remembered and an individual's actual and perceived short-term-memory capacity. Interestingly, individuals often used external storage despite its use affording no observable benefit. Implications for understanding how individuals integrate external resources in pursuing cognitive goals are discussed. Copyright © 2015 Elsevier Inc. All rights reserved.

Reactivation in Working Memory : An Attractor Network Model of Free Recall

OpenAIRE

Lansner, Anders; Marklund, Petter; Sikström, Sverker; Nilsson, Lars-Göran

2013-01-01

The dynamic nature of human working memory, the general-purpose system for processing continuous input, while keeping no longer externally available information active in the background, is well captured in immediate free recall of supraspan word-lists. Free recall tasks produce several benchmark memory phenomena, like the U-shaped serial position curve, reflecting enhanced memory for early and late list items. To account for empirical data, including primacy and recency as well as contiguity...

A nanowire magnetic memory cell based on a periodic magnetic superlattice

International Nuclear Information System (INIS)

Song, J-F; Bird, J P; Ochiai, Y

2005-01-01

We analyse the operation of a semiconductor nanowire-based memory cell. Large changes in the nanowire conductance result when the magnetization of a periodic array of nanoscale magnetic gates, which comprise the other key component of the memory cell, is switched between distinct configurations by an external magnetic field. The resulting conductance change provides the basis for a robust memory effect, which can be implemented in a semiconductor structure compatible with conventional semiconductor integrated circuits

From Focused Thought to Reveries: A Memory System for a Conscious Robot

Directory of Open Access Journals (Sweden)

Christian Balkenius

2018-04-01

Full Text Available We introduce a memory model for robots that can account for many aspects of an inner world, ranging from object permanence, episodic memory, and planning to imagination and reveries. It is modeled after neurophysiological data and includes parts of the cerebral cortex together with models of arousal systems that are relevant for consciousness. The three central components are an identification network, a localization network, and a working memory network. Attention serves as the interface between the inner and the external world. It directs the flow of information from sensory organs to memory, as well as controlling top-down influences on perception. It also compares external sensations to internal top-down expectations. The model is tested in a number of computer simulations that illustrate how it can operate as a component in various cognitive tasks including perception, the A-not-B test, delayed matching to sample, episodic recall, and vicarious trial and error.

Conformal, planarizing and bridging AZ5214-E layers deposited by a 'draping' technique on non-planar III V substrates

Science.gov (United States)

Eliás, P.; Strichovanec, P.; Kostic, I.; Novák, J.

2006-12-01

A draping technique was tested for the deposition of positive-tone AZ5214-E photo-resist layers on non-planar (1 0 0)-oriented III-V substrates, which had a variety of three-dimensional (3D) topographies micromachined in them that consisted, e.g., of mesa ridges confined to side facets with variable tilt, inverted pyramidal holes and stubs confined to perpendicular side facets. All objects were sharp-edged. In each draping experiment, an AZ5214-E sheet was (1) formed floating on the water surface, (2) lowered onto a non-planar substrate and (3) draped over it during drying to form either self-sustained, or conformal, or planarizing layers over the non-planar substrates. The draping process is based on the depression of the glass transition temperature Tg of AZ5214-E material induced by penetrant water molecules that interact with AZ5214-E. During the process, the molecules are initially trapped under an AZ5214-E sheet and then transported out through the sheet via permeation. The water-AZ5214-E interaction modifies the stiffness κ of the sheet. The magnitude of the effect depends on temperature T and on partial water vapour pressure difference p(T, P, κ): the net effect is that Tg = f(C(T, P), p(T, P, κ)) is lowered as the concentration C of water increases with T and p, where P is the permeability of the sheet. The interaction depressed the Tg of the sheets as low as or lower than 53 °C for 6 µm thick sheets. At room temperature T Tg, the sheet becomes rubbery and mouldable by adhesion and capillary forces. As a result, it can either contour or planarize the topography depending on its geometry and thickness of the sheet.

Identification of a Typical CSTR Using Optimal Focused Time Lagged Recurrent Neural Network Model with Gamma Memory Filter

Directory of Open Access Journals (Sweden)

S. N. Naikwad

2009-01-01

Full Text Available A focused time lagged recurrent neural network (FTLR NN with gamma memory filter is designed to learn the subtle complex dynamics of a typical CSTR process. Continuous stirred tank reactor exhibits complex nonlinear operations where reaction is exothermic. It is noticed from literature review that process control of CSTR using neuro-fuzzy systems was attempted by many, but optimal neural network model for identification of CSTR process is not yet available. As CSTR process includes temporal relationship in the input-output mappings, time lagged recurrent neural network is particularly used for identification purpose. The standard back propagation algorithm with momentum term has been proposed in this model. The various parameters like number of processing elements, number of hidden layers, training and testing percentage, learning rule and transfer function in hidden and output layer are investigated on the basis of performance measures like MSE, NMSE, and correlation coefficient on testing data set. Finally effects of different norms are tested along with variation in gamma memory filter. It is demonstrated that dynamic NN model has a remarkable system identification capability for the problems considered in this paper. Thus FTLR NN with gamma memory filter can be used to learn underlying highly nonlinear dynamics of the system, which is a major contribution of this paper.

Scaled model guidelines for solar coronagraphs' external occulters with an optimized shape.

Science.gov (United States)

Landini, Federico; Baccani, Cristian; Schweitzer, Hagen; Asoubar, Daniel; Romoli, Marco; Taccola, Matteo; Focardi, Mauro; Pancrazzi, Maurizio; Fineschi, Silvano

2017-12-01

One of the major challenges faced by externally occulted solar coronagraphs is the suppression of the light diffracted by the occulter edge. It is a contribution to the stray light that overwhelms the coronal signal on the focal plane and must be reduced by modifying the geometrical shape of the occulter. There is a rich literature, mostly experimental, on the appropriate choice of the most suitable shape. The problem arises when huge coronagraphs, such as those in formation flight, shall be tested in a laboratory. A recent contribution [Opt. Lett.41, 757 (2016)OPLEDP0146-959210.1364/OL.41.000757] provides the guidelines for scaling the geometry and replicate in the laboratory the flight diffraction pattern as produced by the whole solar disk and a flight occulter but leaves the conclusion on the occulter scale law somehow unjustified. This paper provides the numerical support for validating that conclusion and presents the first-ever simulation of the diffraction behind an occulter with an optimized shape along the optical axis with the solar disk as a source. This paper, together with Opt. Lett.41, 757 (2016)OPLEDP0146-959210.1364/OL.41.000757, aims at constituting a complete guide for scaling the coronagraphs' geometry.

Fluorescence based fiber optic and planar waveguide biosensors. A review

International Nuclear Information System (INIS)

Benito-Peña, Elena; Valdés, Mayra Granda; Glahn-Martínez, Bettina; Moreno-Bondi, Maria C.

2016-01-01

The application of optical biosensors, specifically those that use optical fibers and planar waveguides, has escalated throughout the years in many fields, including environmental analysis, food safety and clinical diagnosis. Fluorescence is, without doubt, the most popular transducer signal used in these devices because of its higher selectivity and sensitivity, but most of all due to its wide versatility. This paper focuses on the working principles and configurations of fluorescence-based fiber optic and planar waveguide biosensors and will review biological recognition elements, sensing schemes, as well as some major and recent applications, published in the last ten years. The main goal is to provide the reader a general overview of a field that requires the joint collaboration of researchers of many different areas, including chemistry, physics, biology, engineering, and material science. - Highlights: • Principles, configurations and fluorescence techniques using fiber optic and planar waveguide biosensors are discussed. • The biorecognition elements and sensing schemes used in fiber optic and planar waveguide platforms are reviewed. • Some major and recent applications of fiber optic and planar waveguide biosensors are introduced.

Fluorescence based fiber optic and planar waveguide biosensors. A review

Energy Technology Data Exchange (ETDEWEB)

Benito-Peña, Elena [Department of Analytical Chemistry, Faculty of Chemistry, Complutense University, 28040 Madrid (Spain); Valdés, Mayra Granda [Department of Analytical Chemistry, Faculty of Chemistry, University of La Habana, 10400 La Habana (Cuba); Glahn-Martínez, Bettina [Department of Analytical Chemistry, Faculty of Chemistry, Complutense University, 28040 Madrid (Spain); Moreno-Bondi, Maria C., E-mail: mcmbondi@quim.ucm.es [Department of Analytical Chemistry, Faculty of Chemistry, Complutense University, 28040 Madrid (Spain)

2016-11-02

The application of optical biosensors, specifically those that use optical fibers and planar waveguides, has escalated throughout the years in many fields, including environmental analysis, food safety and clinical diagnosis. Fluorescence is, without doubt, the most popular transducer signal used in these devices because of its higher selectivity and sensitivity, but most of all due to its wide versatility. This paper focuses on the working principles and configurations of fluorescence-based fiber optic and planar waveguide biosensors and will review biological recognition elements, sensing schemes, as well as some major and recent applications, published in the last ten years. The main goal is to provide the reader a general overview of a field that requires the joint collaboration of researchers of many different areas, including chemistry, physics, biology, engineering, and material science. - Highlights: • Principles, configurations and fluorescence techniques using fiber optic and planar waveguide biosensors are discussed. • The biorecognition elements and sensing schemes used in fiber optic and planar waveguide platforms are reviewed. • Some major and recent applications of fiber optic and planar waveguide biosensors are introduced.

EQPlanar: a maximum-likelihood method for accurate organ activity estimation from whole body planar projections

International Nuclear Information System (INIS)

Song, N; Frey, E C; He, B; Wahl, R L

2011-01-01

Optimizing targeted radionuclide therapy requires patient-specific estimation of organ doses. The organ doses are estimated from quantitative nuclear medicine imaging studies, many of which involve planar whole body scans. We have previously developed the quantitative planar (QPlanar) processing method and demonstrated its ability to provide more accurate activity estimates than conventional geometric-mean-based planar (CPlanar) processing methods using physical phantom and simulation studies. The QPlanar method uses the maximum likelihood-expectation maximization algorithm, 3D organ volume of interests (VOIs), and rigorous models of physical image degrading factors to estimate organ activities. However, the QPlanar method requires alignment between the 3D organ VOIs and the 2D planar projections and assumes uniform activity distribution in each VOI. This makes application to patients challenging. As a result, in this paper we propose an extended QPlanar (EQPlanar) method that provides independent-organ rigid registration and includes multiple background regions. We have validated this method using both Monte Carlo simulation and patient data. In the simulation study, we evaluated the precision and accuracy of the method in comparison to the original QPlanar method. For the patient studies, we compared organ activity estimates at 24 h after injection with those from conventional geometric mean-based planar quantification using a 24 h post-injection quantitative SPECT reconstruction as the gold standard. We also compared the goodness of fit of the measured and estimated projections obtained from the EQPlanar method to those from the original method at four other time points where gold standard data were not available. In the simulation study, more accurate activity estimates were provided by the EQPlanar method for all the organs at all the time points compared with the QPlanar method. Based on the patient data, we concluded that the EQPlanar method provided a

Memory Transformation Enhances Reinforcement Learning in Dynamic Environments.

Science.gov (United States)

Santoro, Adam; Frankland, Paul W; Richards, Blake A

2016-11-30

Over the course of systems consolidation, there is a switch from a reliance on detailed episodic memories to generalized schematic memories. This switch is sometimes referred to as "memory transformation." Here we demonstrate a previously unappreciated benefit of memory transformation, namely, its ability to enhance reinforcement learning in a dynamic environment. We developed a neural network that is trained to find rewards in a foraging task where reward locations are continuously changing. The network can use memories for specific locations (episodic memories) and statistical patterns of locations (schematic memories) to guide its search. We find that switching from an episodic to a schematic strategy over time leads to enhanced performance due to the tendency for the reward location to be highly correlated with itself in the short-term, but regress to a stable distribution in the long-term. We also show that the statistics of the environment determine the optimal utilization of both types of memory. Our work recasts the theoretical question of why memory transformation occurs, shifting the focus from the avoidance of memory interference toward the enhancement of reinforcement learning across multiple timescales. As time passes, memories transform from a highly detailed state to a more gist-like state, in a process called "memory transformation." Theories of memory transformation speak to its advantages in terms of reducing memory interference, increasing memory robustness, and building models of the environment. However, the role of memory transformation from the perspective of an agent that continuously acts and receives reward in its environment is not well explored. In this work, we demonstrate a view of memory transformation that defines it as a way of optimizing behavior across multiple timescales. Copyright © 2016 the authors 0270-6474/16/3612228-15$15.00/0.