Error characterization for asynchronous computations: Proxy equation approach

Science.gov (United States)

Sallai, Gabriella; Mittal, Ankita; Girimaji, Sharath

2017-11-01

Numerical techniques for asynchronous fluid flow simulations are currently under development to enable efficient utilization of massively parallel computers. These numerical approaches attempt to accurately solve time evolution of transport equations using spatial information at different time levels. The truncation error of asynchronous methods can be divided into two parts: delay dependent (EA) or asynchronous error and delay independent (ES) or synchronous error. The focus of this study is a specific asynchronous error mitigation technique called proxy-equation approach. The aim of this study is to examine these errors as a function of the characteristic wavelength of the solution. Mitigation of asynchronous effects requires that the asynchronous error be smaller than synchronous truncation error. For a simple convection-diffusion equation, proxy-equation error analysis identifies critical initial wave-number, λc. At smaller wave numbers, synchronous error are larger than asynchronous errors. We examine various approaches to increase the value of λc in order to improve the range of applicability of proxy-equation approach.

Asynchronous zero-forcing adaptive equalization

NARCIS (Netherlands)

Bergmans, J.W.M.; Pozidis, H.; Lin, M.Y.

2005-01-01

Digital data receivers often operate at a fixed sampling rate 1/Ts that is asynchronous to the baud rate 1/T. A digital equalizer that processes the incoming signal will also be asynchronous, and its adaptation is commonly based on extensions of the LMS algorithm. In this paper, we develop and

The Aeolian Asynchronous Generator

Directory of Open Access Journals (Sweden)

Ionel Dragomirescu

2008-10-01

Full Text Available The production of the electric energy with lower costs could be realized with the help of the aeolian electric central. In these centrals we can use the squirrel cage asynchronous generators, because these machines are the most safety in function and easy exploited. This work show the function analyzing of the asynchronous generator having on involving torque depending on the square wind speed, the air-density and on the construction of the wing spiral.

Burst-Mode Asynchronous Controllers on FPGA

Directory of Open Access Journals (Sweden)

Duarte L. Oliveira

2008-01-01

Full Text Available FPGAs have been mainly used to design synchronous circuits. Asynchronous design on FPGAs is difficult because the resulting circuit may suffer from hazard problems. We propose a method that implements a popular class of asynchronous circuits, known as burst mode, on FPGAs based on look-up table architectures. We present two conditions that, if satisfied, guarantee essential hazard-free implementation on any LUT-based FPGA. By doing that, besides all the intrinsic advantages of asynchronous over synchronous circuits, they also take advantage of the shorter design time and lower cost associated with FPGA designs.

Comparing the force ripple during asynchronous and conventional stimulation.

Science.gov (United States)

Downey, Ryan J; Tate, Mark; Kawai, Hiroyuki; Dixon, Warren E

2014-10-01

Asynchronous stimulation has been shown to reduce fatigue during electrical stimulation; however, it may also exhibit a force ripple. We quantified the ripple during asynchronous and conventional single-channel transcutaneous stimulation across a range of stimulation frequencies. The ripple was measured during 5 asynchronous stimulation protocols, 2 conventional stimulation protocols, and 3 volitional contractions in 12 healthy individuals. Conventional 40 Hz and asynchronous 16 Hz stimulation were found to induce contractions that were as smooth as volitional contractions. Asynchronous 8, 10, and 12 Hz stimulation induced contractions with significant ripple. Lower stimulation frequencies can reduce fatigue; however, they may also lead to increased ripple. Future efforts should study the relationship between force ripple and the smoothness of the evoked movements in addition to the relationship between stimulation frequency and NMES-induced fatigue to elucidate an optimal stimulation frequency for asynchronous stimulation. © 2014 Wiley Periodicals, Inc.

Monetary and fiscal policy under bounded rationality and heterogeneous expectations

NARCIS (Netherlands)

Lustenhouwer, J.E.

2017-01-01

The goal of this thesis is to use plausible and intuitive models of bounded rationality to give new insights in monetary and fiscal policy. Particular focus is put on the zero lower bound on the nominal interest rate, forward guidance, and fiscal consolidations. The thesis considers different forms

Asynchronous machines. Direct torque control; Machines asynchrones. Commande par controle direct de couple

Energy Technology Data Exchange (ETDEWEB)

Fornel, B. de [Institut National Polytechnique, 31 - Toulouse (France)

2006-05-15

The asynchronous machine, with its low cost and robustness, is today the most widely used motor to make speed variators. However, its main drawback is that the same current generates both the magnetic flux and the torque, and thus any torque variation creates a flux variation. Such a coupling gives to the asynchronous machine a nonlinear behaviour which makes its control much more complex. The direct self control (DSC) method has been developed to improve the low efficiency of the scalar control method and for the specific railway drive application. The direct torque control (DTC) method is derived from the DSC method but corresponds to other type of applications. The DSC and DTC algorithms for asynchronous motors are presented in this article: 1 - direct control of the stator flux (DSC): principle, flux control, torque control, switching frequency of the inverter, speed estimation; 2 - direct torque control (DTC): principle, electromagnetic torque derivative, signals shape and switching frequency, some results, DTC speed variator without speed sensor, DTC application to multi-machine multi-converter systems; 3 - conclusion. (J.S.)

Current Trends in High-Level Synthesis of Asynchronous Circuits

DEFF Research Database (Denmark)

Sparsø, Jens

2009-01-01

This paper is a survey paper presenting what the author sees as two major and promising trends in the current research in CAD-tools and design-methods for asynchronous circuits. One branch of research builds on top of existing asynchronous CAD-tools that perform syntax directed translation, e...... a conventional synchronous circuit as the starting point, and then adds some form of handshake-based flow-control. One approach keeps the global clock and implements discrete-time asynchronous operation. Another approach substitutes the clocked registers by asynchronous handshake-registers, thus creating truly...

Chick Development and Asynchroneous Hatching in the Zebra Finch (Taeniopygia guttata castanotis).

Science.gov (United States)

Ikebuchi, Maki; Okanoya, Kazuo; Hasegawa, Toshikazu; Bischof, Hans-Joachim

2017-10-01

The mode of hatching in birds has important impacts on both parents and chicks, including the costs and risks of breeding for parents, and sibling competition in a clutch. Birds with multiple eggs in a single clutch often begin incubating when most eggs are laid, thereby reducing time of incubation, nursing burden, and sibling competition. In some songbirds and some other species, however, incubation starts immediately after the first egg is laid, and the chicks thus hatch asynchronously. This may result in differences in parental care and in sibling competition based on body size differences among older and younger chicks, which in turn might produce asynchronous development among siblings favoring the first hatchling, and further affect the development and fitness of the chicks after fledging. To determine whether such processes in fact occur in the zebra finch, we observed chick development in 18 clutches of zebra finches. We found that there were effects of asynchronous hatching, but these were smaller than expected and mostly not significant. Our observations suggest that the amount of care given to each chick may be equated with such factors as a camouflage effect of the down feathers, and that the low illumination within the nest also complicates the determination of the hatching order by the parents.

Asynchronous communication in real space process algebra

NARCIS (Netherlands)

Baeten, J.C.M.; Bergstra, J.A.

1991-01-01

A version of classical real space process algebra is given in which messages travel with constant speed through a three-dimensional medium. It follows that communication is asynchronous and has a broadcasting character. A state operator is used to describe asynchronous message transfer and a

Asynchronous communication in real space process algebra

NARCIS (Netherlands)

Bergstra, J.A.; Baeten, J.C.M.

1992-01-01

A version of classical real space process algebra is given in which messages travel with constant speed through a three-dimensional medium. It follows that communication is asynchronous and has a broadcasting character. A state operator is used to describe asynchronous message transfer and a

Asynchronous and corrected-asynchronous numerical solutions of parabolic PDES on MIMD multiprocessors

Science.gov (United States)

Amitai, Dganit; Averbuch, Amir; Itzikowitz, Samuel; Turkel, Eli

1991-01-01

A major problem in achieving significant speed-up on parallel machines is the overhead involved with synchronizing the concurrent process. Removing the synchronization constraint has the potential of speeding up the computation. The authors present asynchronous (AS) and corrected-asynchronous (CA) finite difference schemes for the multi-dimensional heat equation. Although the discussion concentrates on the Euler scheme for the solution of the heat equation, it has the potential for being extended to other schemes and other parabolic partial differential equations (PDEs). These schemes are analyzed and implemented on the shared memory multi-user Sequent Balance machine. Numerical results for one and two dimensional problems are presented. It is shown experimentally that the synchronization penalty can be about 50 percent of run time: in most cases, the asynchronous scheme runs twice as fast as the parallel synchronous scheme. In general, the efficiency of the parallel schemes increases with processor load, with the time level, and with the problem dimension. The efficiency of the AS may reach 90 percent and over, but it provides accurate results only for steady-state values. The CA, on the other hand, is less efficient, but provides more accurate results for intermediate (non steady-state) values.

CCS, locations and asynchronous transition systems

DEFF Research Database (Denmark)

Mukund, Madhavan; Nielsen, Mogens

1992-01-01

We provide a simple non-interleaved operational semantics for CCS in terms of asynchronous transition systems. We identify the concurrency present in the system in a natural way, in terms of events occurring at independent locations in the system. We extend the standard interleaving transition...... system for CCS by introducing labels on the transitions with information about the locations of events. We then show that the resulting transition system is an asynchronous transition system which has the additional property of being elementary, which means that it can also be represented by a 1-safe net....... We also introduce a notion of bisimulation on asynchronous transition systems which preserves independence. We conjecture that the induced equivalence on CCS processes coincides with the notion of location equivalence proposed by Boudol et al....

Parallel asynchronous hardware implementation of image processing algorithms

Science.gov (United States)

Coon, Darryl D.; Perera, A. G. U.

1990-01-01

Research is being carried out on hardware for a new approach to focal plane processing. The hardware involves silicon injection mode devices. These devices provide a natural basis for parallel asynchronous focal plane image preprocessing. The simplicity and novel properties of the devices would permit an independent analog processing channel to be dedicated to every pixel. A laminar architecture built from arrays of the devices would form a two-dimensional (2-D) array processor with a 2-D array of inputs located directly behind a focal plane detector array. A 2-D image data stream would propagate in neuron-like asynchronous pulse-coded form through the laminar processor. No multiplexing, digitization, or serial processing would occur in the preprocessing state. High performance is expected, based on pulse coding of input currents down to one picoampere with noise referred to input of about 10 femtoamperes. Linear pulse coding has been observed for input currents ranging up to seven orders of magnitude. Low power requirements suggest utility in space and in conjunction with very large arrays. Very low dark current and multispectral capability are possible because of hardware compatibility with the cryogenic environment of high performance detector arrays. The aforementioned hardware development effort is aimed at systems which would integrate image acquisition and image processing.

Developing asynchronous online interprofessional education.

Science.gov (United States)

Sanborn, Heidi

2016-09-01

For many health programmes, developing interprofessional education (IPE) has been a challenge. Evidence on the best method for design and implementation of IPE has been slow to emerge, with little research on how to best incorporate IPE in the asynchronous online learning environment. This leaves online programmes with no clear guidance when embarking upon an initiative to integrate IPE into the curriculum. One tool that can be effective at guiding the incorporation of IPE across all learning platforms is the Interprofessional Education Collaborative (IPEC) competencies. A project was designed to integrate the nationally defined IPEC competencies throughout an asynchronous, online baccalaureate nursing completion programme. A programme-wide review led to targeted revision of course and unit-level objectives, learning experiences, and assessments based on the IPEC framework. As a result of this effort, the programme curriculum now provides interprofessional learning activities across all courses. This report provides a method for using the IPEC competencies to incorporate IPE within various asynchronous learning assessments, assuring students learn about, with, and from other professions.

Asynchronous Parallelization of a CFD Solver

OpenAIRE

Abdi, Daniel S.; Bitsuamlak, Girma T.

2015-01-01

The article of record as published may be found at http://dx.doi.org/10.1155/2015/295393 A Navier-Stokes equations solver is parallelized to run on a cluster of computers using the domain decomposition method. Two approaches of communication and computation are investigated, namely, synchronous and asynchronous methods. Asynchronous communication between subdomains is not commonly used inCFDcodes; however, it has a potential to alleviate scaling bottlenecks incurred due to process...

Asynchronous networks: modularization of dynamics theorem

Science.gov (United States)

Bick, Christian; Field, Michael

2017-02-01

Building on the first part of this paper, we develop the theory of functional asynchronous networks. We show that a large class of functional asynchronous networks can be (uniquely) represented as feedforward networks connecting events or dynamical modules. For these networks we can give a complete description of the network function in terms of the function of the events comprising the network: the modularization of dynamics theorem. We give examples to illustrate the main results.

Asynchronous SAR ADC

NARCIS (Netherlands)

2011-01-01

An asynchronous analog to digital convertor for converting an analog input signal into a digital output is presented. According to an embodiment, the analog to digital convertor comprises a clock input operable to receive an external clock signal having a clock period, a comparator operable to

Asynchronous decentralized method for interconnected electricity markets

International Nuclear Information System (INIS)

Huang, Anni; Joo, Sung-Kwan; Song, Kyung-Bin; Kim, Jin-Ho; Lee, Kisung

2008-01-01

This paper presents an asynchronous decentralized method to solve the optimization problem of interconnected electricity markets. The proposed method decomposes the optimization problem of combined electricity markets into individual optimization problems. The impact of neighboring markets' information is included in the objective function of the individual market optimization problem by the standard Lagrangian relaxation method. Most decentralized optimization methods use synchronous models of communication to exchange updated market information among markets during the iterative process. In this paper, however, the solutions of the individual optimization problems are coordinated through an asynchronous communication model until they converge to the global optimal solution of combined markets. Numerical examples are presented to demonstrate the advantages of the proposed asynchronous method over the existing synchronous methods. (author)

Optimization of parameters of special asynchronous electric drives

Science.gov (United States)

Karandey, V. Yu; Popov, B. K.; Popova, O. B.; Afanasyev, V. L.

2018-03-01

The article considers the solution of the problem of parameters optimization of special asynchronous electric drives. The solution of the problem will allow one to project and create special asynchronous electric drives for various industries. The created types of electric drives will have optimum mass-dimensional and power parameters. It will allow one to realize and fulfill the set characteristics of management of technological processes with optimum level of expenses of electric energy, time of completing the process or other set parameters. The received decision allows one not only to solve a certain optimizing problem, but also to construct dependences between the optimized parameters of special asynchronous electric drives, for example, with the change of power, current in a winding of the stator or rotor, induction in a gap or steel of magnetic conductors and other parameters. On the constructed dependences, it is possible to choose necessary optimum values of parameters of special asynchronous electric drives and their components without carrying out repeated calculations.

Multiparty Asynchronous Session Types

DEFF Research Database (Denmark)

Honda, Kohei; Yoshida, Nobuko; Carbone, Marco

2016-01-01

. This work extends the foregoing theories of binary session types to multiparty, asynchronous sessions, which often arise in practical communication-centered applications. Presented as a typed calculus for mobile processes, the theory introduces a new notion of types in which interactions involving multiple......Communication is a central elements in software development. As a potential typed foundation for structured communication-centered programming, session types have been studied over the past decade for a wide range of process calculi and programming languages, focusing on binary (two-party) sessions...... peers are directly abstracted as a global scenario. Global types retain the friendly type syntax of binary session types while specifying dependencies and capturing complex causal chains of multiparty asynchronous interactions. A global type plays the role of a shared agreement among communication peers...

Asynchronous machine rotor speed estimation using a tabulated numerical approach

Science.gov (United States)

Nguyen, Huu Phuc; De Miras, Jérôme; Charara, Ali; Eltabach, Mario; Bonnet, Stéphane

2017-12-01

This paper proposes a new method to estimate the rotor speed of the asynchronous machine by looking at the estimation problem as a nonlinear optimal control problem. The behavior of the nonlinear plant model is approximated off-line as a prediction map using a numerical one-step time discretization obtained from simulations. At each time-step, the speed of the induction machine is selected satisfying the dynamic fitting problem between the plant output and the predicted output, leading the system to adopt its dynamical behavior. Thanks to the limitation of the prediction horizon to a single time-step, the execution time of the algorithm can be completely bounded. It can thus easily be implemented and embedded into a real-time system to observe the speed of the real induction motor. Simulation results show the performance and robustness of the proposed estimator.

Interpolation algorithm for asynchronous ADC-data

Directory of Open Access Journals (Sweden)

S. Bramburger

2017-09-01

Full Text Available This paper presents a modified interpolation algorithm for signals with variable data rate from asynchronous ADCs. The Adaptive weights Conjugate gradient Toeplitz matrix (ACT algorithm is extended to operate with a continuous data stream. An additional preprocessing of data with constant and linear sections and a weighted overlap of step-by-step into spectral domain transformed signals improve the reconstruction of the asycnhronous ADC signal. The interpolation method can be used if asynchronous ADC data is fed into synchronous digital signal processing.

Synchronous and Asynchronous ATM Multiplexor Properties Comparsion

OpenAIRE

Jan Zabka

2006-01-01

The article is aimed to ATM multiplexor computer model utilisation. Based on simulation runs we try to review aspects of use a synchronous and asynchronous ATM multiplexors. ATM multiplexor is the input queuing model with three inputs. Synchronous multiplexor works without an input priority. Multiplexor inputs are served periodically. Asynchronous multiplexor model supports several queuing and priority mechanisms. CLR and CTD are basic performance parameters. Input cell flows are genera...

Asynchronous communication in real space process algebra

OpenAIRE

Baeten, JCM Jos; Bergstra, JA Jan

1990-01-01

A version of classical real space process algebra is given in which messages travel with constant speed through a three-dimensional medium. It follows that communication is asynchronous and has a broadcasting character. A state operator is used to describe asynchronous message transfer and a priority mechanism allows to express the broadcasting mechanism. As an application, a protocol is specified in which the receiver moves with respect to the sender.

Asynchronous Learning Sources in a High-Tech Organization

Science.gov (United States)

Bouhnik, Dan; Giat, Yahel; Sanderovitch, Yafit

2009-01-01

Purpose: The purpose of this study is to characterize learning from asynchronous sources among research and development (R&D) personnel. It aims to examine four aspects of asynchronous source learning: employee preferences regarding self-learning; extent of source usage; employee satisfaction with these sources and the effect of the sources on the…

TCDQ-TCT retraction and losses during asynchronous beam dump

CERN Document Server

Bracco, Chiara; Quaranta, Elena; CERN. Geneva. ATS Department

2016-01-01

The protection provided by the TCDQs in case of asynchronous beam dump depends strongly on their correct setup. They have to respect the strict hierarchy of the full collimation system and shield the tertiary collimators in the experimental regions. This MD aimed at performing asynchronous beam dump tests with different configurations, in order to assess the minimum allowed retraction between TCTs and TCDQs and, as a consequence, on the The protection provided by the TCDQs in case of asynchronous beam dump depends strongly on their correct setup. They have to respect the strict hierarchy of the full collimation system and shield the tertiary collimators in the experimental regions. This MD aimed at performing asynchronous beam dump tests with different configurations, in order to assess the minimum allowed retraction between TCTs and TCDQs and, as a consequence, on the β* reach.

Basic Algorithms for the Asynchronous Reconfigurable Mesh

Directory of Open Access Journals (Sweden)

Yosi Ben-Asher

2002-01-01

Full Text Available Many constant time algorithms for various problems have been developed for the reconfigurable mesh (RM in the past decade. All these algorithms are designed to work with synchronous execution, with no regard for the fact that large size RMs will probably be asynchronous. A similar observation about the PRAM model motivated many researchers to develop algorithms and complexity measures for the asynchronous PRAM (APRAM. In this work, we show how to define the asynchronous reconfigurable mesh (ARM and how to measure the complexity of asynchronous algorithms executed on it. We show that connecting all processors in a row of an n×n ARM (the analog of barrier synchronization in the APRAM model can be solved with complexity Θ(nlog⁡n. Intuitively, this is average work time for solving such a problem. Next, we describe general a technique for simulating T -step synchronous RM algorithms on the ARM with complexity of Θ(T⋅n2log⁡n. Finally, we consider the simulation of the classical synchronous algorithm for counting the number of non-zero bits in an n bits vector using (k

Pharmacists' perception of synchronous versus asynchronous distance learning for continuing education programs.

Science.gov (United States)

Buxton, Eric C

2014-02-12

To evaluate and compare pharmacists' satisfaction with the content and learning environment of a continuing education program series offered as either synchronous or asynchronous webinars. An 8-lecture series of online presentations on the topic of new drug therapies was offered to pharmacists in synchronous and asynchronous webinar formats. Participants completed a 50-question online survey at the end of the program series to evaluate their perceptions of the distance learning experience. Eighty-two participants completed the survey instrument (41 participants from the live webinar series and 41 participants from the asynchronous webinar series.) Responses indicated that while both groups were satisfied with the program content, the asynchronous group showed greater satisfaction with many aspects of the learning environment. The synchronous and asynchronous webinar participants responded positively regarding the quality of the programming and the method of delivery, but asynchronous participants rated their experience more positively overall.

Designing Asynchronous Circuits for Low Power: An IFIR Filter

DEFF Research Database (Denmark)

Nielsen, Lars Skovby; Sparsø, Jens

1999-01-01

This paper addresses the design of asynchronous circuits for low power through an example: a filter bank for a digital hearing aid. The asynchronous design re-implements an existing synchronous circuit which is used in a commercial product. For comparison, both designs have been fabricated...

FPGA BASED ASYNCHRONOUS PIPELINED MB-OFDM UWB TRANSMITTER BACKEND MODULES

Directory of Open Access Journals (Sweden)

M. Santhi

2010-03-01

Full Text Available In this paper, a novel scheme is proposed which comprises the advantages of asynchronous pipelining techniques and the advantages of FPGAs for implementing a 200Mbps MB-OFDM UWB transmitter digital backend modules. In asynchronous pipelined system, registers are used as in synchronous system. But they are controlled by handshaking signals. Since FPGAs are rich in registers, design and implementation of asynchronous pipelined MBOFDM UWB transmitter on FPGA using four-phase bundled-data protocol is considered in this paper. Novel ideas have also been proposed for designing asynchronous OFDM using Modified Radix-24 SDF and asynchronous interleaver using two RAM banks. Implementation has been performed on ALTERA STRATIX II EP2S60F1020C4 FPGA and it is operating at a speed of 350MHz. It is assured that the proposed MB-OFDM UWB system can be made to work on STRATIX III device with the operating frequency of 528MHz in compliance to the ECMA-368 standard. The proposed scheme is also applicable for FPGA from other vendors and ASIC.

Integrating Asynchronous Digital Design Into the Computer Engineering Curriculum

Science.gov (United States)

Smith, S. C.; Al-Assadi, W. K.; Di, J.

2010-01-01

As demand increases for circuits with higher performance, higher complexity, and decreased feature size, asynchronous (clockless) paradigms will become more widely used in the semiconductor industry, as evidenced by the International Technology Roadmap for Semiconductors' (ITRS) prediction of a likely shift from synchronous to asynchronous design…

Exploring Asynchronous and Synchronous Tool Use in Online Courses

Science.gov (United States)

Oztok, Murat; Zingaro, Daniel; Brett, Clare; Hewitt, Jim

2013-01-01

While the independent contributions of synchronous and asynchronous interaction in online learning are clear, comparatively less is known about the pedagogical consequences of using both modes in the same environment. In this study, we examine relationships between students' use of asynchronous discussion forums and synchronous private messages…

An Overview of the Asynchronous Digital Systems – Part 3

Directory of Open Access Journals (Sweden)

Mihai Timis

2008-01-01

Full Text Available Implementation methods for the digital asynchronous systems use different predefined models like self timed circuits, speed independent circuits, delay insensitive circuits, handshake protocol implementation in asynchronous systems,C Muller circuits.

An Overview of the Asynchronous Digital Systems – Part 2

Directory of Open Access Journals (Sweden)

Mihai Timis

2008-01-01

Full Text Available Implementation methods for the digital asynchronous systems use different predefined models like self timed circuits, speed independent circuits, delay insensitive circuits, handshake protocol implementation in asynchronous systems,C Muller circuits.

Router Designs for an Asynchronous Time-Division-Multiplexed Network-on-Chip

DEFF Research Database (Denmark)

Kasapaki, Evangelia; Sparsø, Jens; Sørensen, Rasmus Bo

2013-01-01

In this paper we explore the design of an asynchronous router for a time-division-multiplexed (TDM) network-on-chip (NOC) that is being developed for a multi-processor platform for hard real-time systems. TDM inherently requires a common time reference, and existing TDM-based NOC designs are either....... This adds hardware complexity and increases area and power consumption. We propose to use asynchronous routers in order to achieve a simpler, more robust and globally-asynchronous NOC, and this represents an unexplored point in the design space. The paper presents a range of alternative router designs. All...... routers have been synthesized for a 65nm CMOS technology, and the paper reports post-layout figures for area, speed and energy and compares the asynchronous designs with an existing mesochronous clocked router. The results show that an asynchronous router is 2 times smaller, marginally slower...

Evaluation of discrete modeling efficiency of asynchronous electric machines

OpenAIRE

Byczkowska-Lipińska, Liliana; Stakhiv, Petro; Hoholyuk, Oksana; Vasylchyshyn, Ivanna

2011-01-01

In the paper the problem of effective mathematical macromodels in the form of state variables intended for asynchronous motor transient analysis is considered. Their comparing with traditional mathematical models of asynchronous motors including models built into MATLAB/Simulink software was carried out and analysis of their efficiency was conducted.

Two Studies Examining Argumentation in Asynchronous Computer Mediated Communication

Science.gov (United States)

Joiner, Richard; Jones, Sarah; Doherty, John

2008-01-01

Asynchronous computer mediated communication (CMC) would seem to be an ideal medium for supporting development in student argumentation. This paper investigates this assumption through two studies. The first study compared asynchronous CMC with face-to-face discussions. The transactional and strategic level of the argumentation (i.e. measures of…

MODELING AND INVESTIGATION OF ASYNCHRONOUS TWO-MACHINE SYSTEM MODES

Directory of Open Access Journals (Sweden)

V. S. Safaryan

2014-01-01

Full Text Available The paper considers stationary and transient processes of an asynchronous two-machine system. A mathematical model for investigation of stationary and transient modes, static characteristics and research results of dynamic process pertaining to starting-up the asynchronous two-machine system has been given in paper.

PsychVACS: a system for asynchronous telepsychiatry.

Science.gov (United States)

Odor, Alberto; Yellowlees, Peter; Hilty, Donald; Parish, Michelle Burke; Nafiz, Najia; Iosif, Ana-Maria

2011-05-01

To describe the technical development of an asynchronous telepsychiatry application, the Psychiatric Video Archiving and Communication System. A client-server application was developed in Visual Basic.Net with Microsoft(®) SQL database as the backend. It includes the capability of storing video-recorded psychiatric interviews and manages the workflow of the system with automated messaging. Psychiatric Video Archiving and Communication System has been used to conduct the first ever series of asynchronous telepsychiatry consultations worldwide. A review of the software application and the process as part of this project has led to a number of improvements that are being implemented in the next version, which is being written in Java. This is the first description of the use of video recorded data in an asynchronous telemedicine application. Primary care providers and consulting psychiatrists have found it easy to work with and a valuable resource to increase the availability of psychiatric consultation in remote rural locations.

ASCERTAINMENT OF THE EQUIVALENT CIRCUIT PARAMETERS OF THE ASYNCHRONOUS MACHINE

Directory of Open Access Journals (Sweden)

V. S. Safaryan

2015-01-01

Full Text Available The article considers experimental and analytical determination of the asynchronous machine equivalent-circuit parameters with application of the reference data. Transient processes investigation of the asynchronous machines necessitates the equivalent circuit parameters (resistance impedance, inductances and coefficient of the stator-rotor contours mutual inductance that help form the transitory-process mathematical simulation model. The reference books do not provide those parameters; they instead give the rated ones (active power, voltage, slide, coefficient of performance and capacity coefficient as well as the ratio of starting and nominal currents and torques. The noted studies on the asynchronous machine equivalent-circuits parametrization fail to solve the problems ad finem or solve them with admissions. The paper presents experimental and analytical determinations of the asynchronous machine equivalent-circuit parameters: the experimental one based on the results of two measurements and the analytical one where the problem boils down to solving a system of nonlineal algebraic equations. The authors investigate the equivalent asynchronous machine input-resistance properties and adduce the dependence curvatures of the input-resistances on the slide. They present a symbolic model for analytical parameterization of the asynchronous machine equivalent-circuit that represents a system of nonlineal equations and requires one of the rotor-parameters arbitrary assignment. The article demonstrates that for the asynchronous machine equivalent-circuit experimental parameterization the measures are to be conducted of the stator-circuit voltage, current and active power with two different slides and arbitrary assignment of one of the rotor parameters. The paper substantiates the fact that additional measurement does not discard the rotor-parameter choice arbitrariness. The authors establish that in motoring mode there is a critical slide by which the

Asynchronous Operators of Sequential Logic Venjunction & Sequention

CERN Document Server

Vasyukevich, Vadim

2011-01-01

This book is dedicated to new mathematical instruments assigned for logical modeling of the memory of digital devices. The case in point is logic-dynamical operation named venjunction and venjunctive function as well as sequention and sequentional function. Venjunction and sequention operate within the framework of sequential logic. In a form of the corresponding equations, they organically fit analytical expressions of Boolean algebra. Thus, a sort of symbiosis is formed using elements of asynchronous sequential logic on the one hand and combinational logic on the other hand. So, asynchronous

Approximating Frequent Items in Asynchronous Data Stream over a Sliding Window

Directory of Open Access Journals (Sweden)

Ho-Leung Chan

2011-09-01

Full Text Available In an asynchronous data stream, the data items may be out of order with respect to their original timestamps. This paper studies the space complexity required by a data structure to maintain such a data stream so that it can approximate the set of frequent items over a sliding time window with sufficient accuracy. Prior to our work, the best solution is given by Cormode et al. [1], who gave an O (1/ε log W log (εB/ log W min {log W, 1/ε} log |U|- space data structure that can approximate the frequent items within an ε error bound, where W and B are parameters of the sliding window, and U is the set of all possible item names. We gave a more space-efficient data structure that only requires O (1/ε log W log (εB/ logW log log W space.

[A novel proposal explaining sleep disturbance of children in Japan--asynchronization].

Science.gov (United States)

Kohyama, Jun

2008-07-01

It has been reported that more than half of the children in Japan suffer from daytime sleepiness. In contrast, about one quarter of junior high-school students in Japan complain of insomnia. According to the International Classification of Sleep Disorders (Second edition), these children could be diagnosed as having behaviorally-induced insufficient sleep syndrome due to inadequate sleeping habits. Getting on adequate amount of sleep should solve such problems;however, such a therapeutic approach often fails. Although social factors are involved in these sleep disturbances, I feel that a novel notion - asynchronization - leads to an understanding of the pathophysiology of disturbances in these children. Further, it could contribute to resolve their problems. The essence of asynchronization is a disturbance of various aspects (e.g., cycle, amplitude, phase, and interrelationship) of the biological rhythms that normally exhibits circadian oscillation. The main cause of asynchronization is hypothesized to be the combination of light exposure during night and the lack of light exposure in the morning. Asynchronization results in the disturbance of variable systems. Thus, symptoms of asynchronization include disturbances of the autonomic nervous system (sleepiness, insomnia, disturbance of hormonal excretion, gastrointestinal problems, etc.) and higher brain function (disorientation, loss of sociality, loss of will or motivation, impaired alertness and performance, etc.). Neurological (attention deficit, aggression, impulsiveness, hyperactivity, etc.), psychiatric (depressive disorders, personality disorders, anxiety disorders, etc.) and somatic (tiredness, fatigue, etc.) disturbances could also be symptoms of asynchronization. At the initial phase of asynchronization, disturbances are functional and can be resolved relatively easily, such as by the establishment of a regular sleep-wakefulness cycle;however, without adequate intervention the disturbances could gradually

Localized radio frequency communication using asynchronous transfer mode protocol

Science.gov (United States)

Witzke, Edward L.; Robertson, Perry J.; Pierson, Lyndon G.

2007-08-14

A localized wireless communication system for communication between a plurality of circuit boards, and between electronic components on the circuit boards. Transceivers are located on each circuit board and electronic component. The transceivers communicate with one another over spread spectrum radio frequencies. An asynchronous transfer mode protocol controls communication flow with asynchronous transfer mode switches located on the circuit boards.

Electrotechnics - AC motors. Asynchronous and brush-less motors - Lecture and exercises with solutions; Electrotechnique - Moteurs a courant alternatif. Moteurs asynchrones et brushless - Cours et problemes resolus

Energy Technology Data Exchange (ETDEWEB)

Jacob, D.

2005-07-01

This book proposes a presentation of AC electric motors essentially based on physics and technology. Its originality consists in avoiding to use mathematical formulations (like Park's transformation). The modeling retained, which only uses magnetic momentum, magnetic fields and reluctance concepts, leads simply and naturally to the vectorial control principle. The book develops some lecture elements which includes some topics rarely considered like the dimensioning of an asynchronous motor or of a single-phase brush-less motor. Experimental results illustrate the physical phenomena described and many original problems are resolved and commented at the end of each chapter. Content: signals and systems in electrotechnics, torque and rotating magnetic fields generation, asynchronous machine in permanent regime, speed variation of the asynchronous motor, special asynchronous motors, synchronous machine in permanent regime, brush-less motor, note about step motors, note about inverters, index. (J.S.)

Behavioral Synthesis of Asynchronous Circuits Using Syntax Directed Translation as Backend

DEFF Research Database (Denmark)

Nielsen, Sune Fallgaard; Sparsø, Jens; Madsen, Jan

2009-01-01

The current state-of-the art in high-level synthesis of asynchronous circuits is syntax directed translation, which performs a one-to-one mapping of a HDL-description into a corresponding circuit. This paper presents a method for behavioral synthesis of asynchronous circuits which builds on top...... description language Balsa [1]. This ”conventional” template architecture allows us to adapt traditional synchronous synthesis techniques for resource sharing, scheduling, binding etc, to the domain of asynchronous circuits. A prototype tool has been implemented on top of the Balsa framework, and the method...... is illustrated through the implementation of a set of example circuits. The main contributions of the paper are: the fundamental idea, the template architecture and its implementation using asynchronous handshake components, and the implementation of a prototype tool....

Dynamic modeling of an asynchronous squirrel-cage machine; Modelisation dynamique d'une machine asynchrone a cage

Energy Technology Data Exchange (ETDEWEB)

Guerette, D.

2009-07-01

This document presented a detailed mathematical explanation and validation of the steps leading to the development of an asynchronous squirrel-cage machine. The MatLab/Simulink software was used to model a wind turbine at variable high speeds. The asynchronous squirrel-cage machine is an electromechanical system coupled to a magnetic circuit. The resulting electromagnetic circuit can be represented as a set of resistances, leakage inductances and mutual inductances. Different models were used for a comparison study, including the Munteanu, Boldea, Wind Turbine Blockset, and SimPowerSystem. MatLab/Simulink modeling results were in good agreement with the results from other comparable models. Simulation results were in good agreement with analytical calculations. 6 refs, 2 tabs, 9 figs.

Asynchronous and Synchronous Online Discussion: Real and Perceived Achievement Differences

Science.gov (United States)

Johnson, Genevieve Marie; Buck, George H.

2007-01-01

Students in an introductory educational psychology course used two WebCT communication tools (synchronous chat and asynchronous discussion) to discuss four case studies. In response to the item, "I learned the case studies best when using," 39 students selected synchronous chat and 51 students selected asynchronous discussion. Students who…

No-arbitrage bounds for financial scenarios

DEFF Research Database (Denmark)

Geyer, Alois; Hanke, Michael; Weissensteiner, Alex

2014-01-01

We derive no-arbitrage bounds for expected excess returns to generate scenarios used in financial applications. The bounds allow to distinguish three regions: one where arbitrage opportunities will never exist, a second where arbitrage may be present, and a third, where arbitrage opportunities...

DESIGN METHODOLOGY OF SELF-EXCITED ASYNCHRONOUS GENERATOR

Directory of Open Access Journals (Sweden)

Berzan V.

2012-04-01

Full Text Available The paper sets out the methodology of designing an asynchronous generator with capacitive self-excitation. It is known that its design is possible on the basis of serial synchronous motor with squirrel cage rotor. With this approach, the design reworked only the stator winding of electrical machines, making it cost-effectively implement the creation of the generator. Therefore, the methodology for the design, optimization calculations, the development scheme and the stator winding excitation system gain, not only of practical interest, and may also be useful for specialists in the field of electrical machines in the design of asynchronous generators.

Handbook of asynchronous machines with variable speed

CERN Document Server

Razik, Hubert

2013-01-01

This handbook deals with the asynchronous machine in its close environment. It was born from a reflection on this electromagnetic converter whose integration in industrial environments takes a wide part. Previously this type of motor operated at fixed speed, from now on it has been integrated more and more in processes at variable speed. For this reason it seemed useful, or necessary, to write a handbook on the various aspects from the motor in itself, via the control and while finishing by the diagnosis aspect. Indeed, an asynchronous motor is used nowadays in industry where variation speed a

Reliable self-replicating machines in asynchronous cellular automata.

Science.gov (United States)

Lee, Jia; Adachi, Susumu; Peper, Ferdinand

2007-01-01

We propose a self-replicating machine that is embedded in a two-dimensional asynchronous cellular automaton with von Neumann neighborhood. The machine dynamically encodes its shape into description signals, and despite the randomness of cell updating, it is able to successfully construct copies of itself according to the description signals. Self-replication on asynchronously updated cellular automata may find application in nanocomputers, where reconfigurability is an essential property, since it allows avoidance of defective parts and simplifies programming of such computers.

Functional asynchronous networks: Factorization of dynamics and function

Directory of Open Access Journals (Sweden)

Bick Christian

2016-01-01

Full Text Available In this note we describe the theory of functional asynchronous networks and one of the main results, the Modularization of Dynamics Theorem, which for a large class of functional asynchronous networks gives a factorization of dynamics in terms of constituent subnetworks. For these networks we can give a complete description of the network function in terms of the function of the events comprising the network and thereby answer a question originally raised by Alon in the context of biological networks.

Low-power Implementation of an Encryption/Decryption System with Asynchronous Techniques

Directory of Open Access Journals (Sweden)

Nikos Sklavos

2002-01-01

Full Text Available An asynchronous VLSI implementation of the International Data Encryption Algorithm (IDEA is presented in this paper. In order to evaluate the asynchronous design a synchronous version of the algorithm was also designed. VHDL hardware description language was used in order to describe the algorithm. By using Synopsys commercial available tools the VHDL code was synthesized. After placing and routing both designs were fabricated with 0.6 μm CMOS technology. With a system clock of up to 8 MHz and a power supply of 5 V the two chips were tested and evaluated comparing with the software implementation of the IDEA algorithm. This new approach proves efficiently the lowest power consumption of the asynchronous implementation compared to the existing synchronous. Therefore, the asynchronous chip performs efficiently in Wireless Encryption Protocols and high speed networks.

Application of intelligent soft start in asynchronous motor

Science.gov (United States)

Du, Xue; Ye, Ying; Wang, Yuelong; Peng, Lei; Zhang, Suying

2018-05-01

The starting way of three phase asynchronous motor has full voltage start and step-down start. Direct starting brings large current impact, causing excessive local temperature to the power grid and larger starting torque will also impact the motor equipment and affect the service life of the motor. Aim at the problem of large current and torque caused by start-up, an intelligent soft starter is proposed. Through the application of intelligent soft start on asynchronous motor, highlights its application advantage in motor control.

Distributed Consensus of Stochastic Delayed Multi-agent Systems Under Asynchronous Switching.

Science.gov (United States)

Wu, Xiaotai; Tang, Yang; Cao, Jinde; Zhang, Wenbing

2016-08-01

In this paper, the distributed exponential consensus of stochastic delayed multi-agent systems with nonlinear dynamics is investigated under asynchronous switching. The asynchronous switching considered here is to account for the time of identifying the active modes of multi-agent systems. After receipt of confirmation of mode's switching, the matched controller can be applied, which means that the switching time of the matched controller in each node usually lags behind that of system switching. In order to handle the coexistence of switched signals and stochastic disturbances, a comparison principle of stochastic switched delayed systems is first proved. By means of this extended comparison principle, several easy to verified conditions for the existence of an asynchronously switched distributed controller are derived such that stochastic delayed multi-agent systems with asynchronous switching and nonlinear dynamics can achieve global exponential consensus. Two examples are given to illustrate the effectiveness of the proposed method.

The Determination of the Asynchronous Traction Motor Characteristics of Locomotive

Directory of Open Access Journals (Sweden)

Pavel Grigorievich Kolpakhchyan

2017-01-01

Full Text Available The article deals with the problem of the locomotive asynchronous traction motor control with the AC diesel-electric transmission. The limitations of the torque of the traction motor when powered by the inverter are determined. The recommendations to improve the use of asynchronous traction motor of locomotives with the AC diesel-electric transmission are given.

OFDM with Index Modulation for Asynchronous mMTC Networks.

Science.gov (United States)

Doğan, Seda; Tusha, Armed; Arslan, Hüseyin

2018-04-21

One of the critical missions for next-generation wireless communication systems is to fulfill the high demand for massive Machine-Type Communications (mMTC). In mMTC systems, a sporadic transmission is performed between machine users and base station (BS). Lack of coordination between the users and BS in time destroys orthogonality between the subcarriers, and causes inter-carrier interference (ICI). Therefore, providing services to asynchronous massive machine users is a major challenge for Orthogonal Frequency Division Multiplexing (OFDM). In this study, OFDM with index modulation (OFDM-IM) is proposed as an eligible solution to alleviate ICI caused by asynchronous transmission in uncoordinated mMTC networks. In OFDM-IM, data transmission is performed not only by modulated subcarriers but also by the indices of active subcarriers. Unlike classical OFDM, fractional subcarrier activation leads to less ICI in OFDM-IM technology. A novel subcarrier mapping scheme (SMS) named as Inner Subcarrier Activation is proposed to further alleviate adjacent user interference in asynchronous OFDM-IM-based systems. ISA reduces inter-user interference since it gives more activation priority to inner subcarriers compared with the existing SMS-s. The superiority of the proposed SMS is shown through both theoretical analysis and computer-based simulations in comparison to existing mapping schemes for asynchronous systems.

Asynchronous control for networked systems

CERN Document Server

Rubio, Francisco; Bencomo, Sebastián

2015-01-01

This book sheds light on networked control systems; it describes different techniques for asynchronous control, moving away from the periodic actions of classical control, replacing them with state-based decisions and reducing the frequency with which communication between subsystems is required. The text focuses specially on event-based control. Split into two parts, Asynchronous Control for Networked Systems begins by addressing the problems of single-loop networked control systems, laying out various solutions which include two alternative model-based control schemes (anticipatory and predictive) and the use of H2/H∞ robust control to deal with network delays and packet losses. Results on self-triggering and send-on-delta sampling are presented to reduce the need for feedback in the loop. In Part II, the authors present solutions for distributed estimation and control. They deal first with reliable networks and then extend their results to scenarios in which delays and packet losses may occur. The novel ...

Comparing face-to-face, synchronous, and asynchronous learning: postgraduate dental resident preferences.

Science.gov (United States)

Kunin, Marc; Julliard, Kell N; Rodriguez, Tobias E

2014-06-01

The Department of Dental Medicine of Lutheran Medical Center has developed an asynchronous online curriculum consisting of prerecorded PowerPoint presentations with audio explanations. The focus of this study was to evaluate if the new asynchronous format satisfied the educational needs of the residents compared to traditional lecture (face-to-face) and synchronous (distance learning) formats. Lectures were delivered to 219 dental residents employing face-to-face and synchronous formats, as well as the new asynchronous format; 169 (77 percent) participated in the study. Outcomes were assessed with pretests, posttests, and individual lecture surveys. Results found the residents preferred face-to-face and asynchronous formats to the synchronous format in terms of effectiveness and clarity of presentations. This preference was directly related to the residents' perception of how well the technology worked in each format. The residents also rated the quality of student-instructor and student-student interactions in the synchronous and asynchronous formats significantly higher after taking the lecture series than they did before taking it. However, they rated the face-to-face format as significantly more conducive to student-instructor and student-student interaction. While the study found technology had a major impact on the efficacy of this curricular model, the results suggest that the asynchronous format can be an effective way to teach a postgraduate course.

Scrolling toward Enrollment: Web Site Content and the E-Expectations of College-Bound Seniors. E-Expectations

Science.gov (United States)

Noel-Levitz, Inc, 2009

2009-01-01

Communicating with prospective students has undergone a profound transformation in the past ten years. Campus marketing--like marketing for any organization--had to adapt first to the Internet and e-mail and now to new social media formats like social networking and blogging. A recent survey of 1,000 college-bound seniors, however, shows that…

Modeling and Analysis of Asynchronous Systems Using SAL and Hybrid SAL

Science.gov (United States)

Tiwari, Ashish; Dutertre, Bruno

2013-01-01

We present formal models and results of formal analysis of two different asynchronous systems. We first examine a mid-value select module that merges the signals coming from three different sensors that are each asynchronously sampling the same input signal. We then consider the phase locking protocol proposed by Daly, Hopkins, and McKenna. This protocol is designed to keep a set of non-faulty (asynchronous) clocks phase locked even in the presence of Byzantine-faulty clocks on the network. All models and verifications have been developed using the SAL model checking tools and the Hybrid SAL abstractor.

Supporting collaborative discussions on asynchronous time: a technological perspective

OpenAIRE

Caballé, Santi

2011-01-01

The aim of this paper is to report on an experience of using an innovative on-line learning tool to support real, collaborative learning through discussion in asynchronous time. While asynchronous interaction gives rise to unique opportunities that support active, collaborative learning, unique problems also arise, such as frustration, caused by waiting for other peoples' reactions and feedback and the consequent loss of motivation, which has a negative impact on learning outcomes. In order t...

EPOS for Coordination of Asynchronous Sensor Webs

Data.gov (United States)

National Aeronautics and Space Administration — Develop, integrate, and deploy software-based tools to coordinate asynchronous, distributed missions and optimize observation planning spanning simultaneous...

Multithreaded Asynchronous Graph Traversal for In-Memory and Semi-External Memory

KAUST Repository

Pearce, Roger

2010-11-01

Processing large graphs is becoming increasingly important for many domains such as social networks, bioinformatics, etc. Unfortunately, many algorithms and implementations do not scale with increasing graph sizes. As a result, researchers have attempted to meet the growing data demands using parallel and external memory techniques. We present a novel asynchronous approach to compute Breadth-First-Search (BFS), Single-Source-Shortest-Paths, and Connected Components for large graphs in shared memory. Our highly parallel asynchronous approach hides data latency due to both poor locality and delays in the underlying graph data storage. We present an experimental study applying our technique to both In-Memory and Semi-External Memory graphs utilizing multi-core processors and solid-state memory devices. Our experiments using synthetic and real-world datasets show that our asynchronous approach is able to overcome data latencies and provide significant speedup over alternative approaches. For example, on billion vertex graphs our asynchronous BFS scales up to 14x on 16-cores. © 2010 IEEE.

Lessons from Learning to Have Rational Expectations

OpenAIRE

Lindh, Thomas

1989-01-01

This paper reviews a growing literature investigating how economic agents may learn rational expectations. Fully rational learning requires implausible initial information assumptions, therefore some form of bounded rationality has come into focus. Such learning models often converge to rational expectations equilibria within certain bounds. Convergence analysis has been much simplified by methods from adaptive control theory. Learning stability as a correspondence principle show some promise...

A Block-Asynchronous Relaxation Method for Graphics Processing Units

OpenAIRE

Anzt, H.; Dongarra, J.; Heuveline, Vincent; Tomov, S.

2011-01-01

In this paper, we analyze the potential of asynchronous relaxation methods on Graphics Processing Units (GPUs). For this purpose, we developed a set of asynchronous iteration algorithms in CUDA and compared them with a parallel implementation of synchronous relaxation methods on CPU-based systems. For a set of test matrices taken from the University of Florida Matrix Collection we monitor the convergence behavior, the average iteration time and the total time-to-solution time. Analyzing the r...

Novel Asynchronous Wrapper and Its Application to GALS Systems

Institute of Scientific and Technical Information of China (English)

Zhuang Shengxian; Peng Anjin; Lars Wanhammar

2006-01-01

An asynchronous wrapper with novel handshake circuits for data communication in globally asynchronous locally synchronous (GALS) systems is proposed. The handshake circuits include two communication ports and a local clock generator. Two approaches for the implementation of communication ports are presented, one with pure standard cells and the others with Müller-C elements. The detailed design methodology for GALS systems is given and the circuits are validated with VHDL and circuits simulation in standard CMOS technology.

Blending Online Asynchronous and Synchronous Learning

Directory of Open Access Journals (Sweden)

Lisa C. Yamagata-Lynch

2014-04-01

Full Text Available In this article I will share a qualitative self-study about a 15-week blended 100% online graduate level course facilitated through synchronous meetings on Blackboard Collaborate and asynchronous discussions on Blackboard. I taught the course at the University of Tennessee (UT during the spring 2012 semester and the course topic was online learning environments. The primary research question of this study was: How can the designer/instructor optimize learning experiences for students who are studying about online learning environments in a blended online course relying on both synchronous and asynchronous technologies? I relied on student reflections of course activities during the beginning, middle, and the end of the semester as the primary data source to obtain their insights regarding course experiences. Through the experiences involved in designing and teaching the course and engaging in this study I found that there is room in the instructional technology research community to address strategies for facilitating online synchronous learning that complement asynchronous learning. Synchronous online whole class meetings and well-structured small group meetings can help students feel a stronger sense of connection to their peers and instructor and stay engaged with course activities. In order to provide meaningful learning spaces in synchronous learning environments, the instructor/designer needs to balance the tension between embracing the flexibility that the online space affords to users and designing deliberate structures that will help them take advantage of the flexible space.

A Synchronous-Asynchronous Particle Swarm Optimisation Algorithm

Science.gov (United States)

Ab Aziz, Nor Azlina; Mubin, Marizan; Mohamad, Mohd Saberi; Ab Aziz, Kamarulzaman

2014-01-01

In the original particle swarm optimisation (PSO) algorithm, the particles' velocities and positions are updated after the whole swarm performance is evaluated. This algorithm is also known as synchronous PSO (S-PSO). The strength of this update method is in the exploitation of the information. Asynchronous update PSO (A-PSO) has been proposed as an alternative to S-PSO. A particle in A-PSO updates its velocity and position as soon as its own performance has been evaluated. Hence, particles are updated using partial information, leading to stronger exploration. In this paper, we attempt to improve PSO by merging both update methods to utilise the strengths of both methods. The proposed synchronous-asynchronous PSO (SA-PSO) algorithm divides the particles into smaller groups. The best member of a group and the swarm's best are chosen to lead the search. Members within a group are updated synchronously, while the groups themselves are asynchronously updated. Five well-known unimodal functions, four multimodal functions, and a real world optimisation problem are used to study the performance of SA-PSO, which is compared with the performances of S-PSO and A-PSO. The results are statistically analysed and show that the proposed SA-PSO has performed consistently well. PMID:25121109

The Design of Finite State Machine for Asynchronous Replication Protocol

Science.gov (United States)

Wang, Yanlong; Li, Zhanhuai; Lin, Wei; Hei, Minglei; Hao, Jianhua

Data replication is a key way to design a disaster tolerance system and to achieve reliability and availability. It is difficult for a replication protocol to deal with the diverse and complex environment. This means that data is less well replicated than it ought to be. To reduce data loss and to optimize replication protocols, we (1) present a finite state machine, (2) run it to manage an asynchronous replication protocol and (3) report a simple evaluation of the asynchronous replication protocol based on our state machine. It's proved that our state machine is applicable to guarantee the asynchronous replication protocol running in the proper state to the largest extent in the event of various possible events. It also can helpful to build up replication-based disaster tolerance systems to ensure the business continuity.

MED5/355: Using Web-technology for Asynchronous Telemedicine Consulting

OpenAIRE

Reviakin, Y; Sukhanov, A

1999-01-01

Introduction Common telemedicine consultations can be divided in two classes: real-time telemedicine consultations and asynchronous telemedicine consultations. The advantage of real-time consultations is obvious - this is a natural discussion between physicians, which may be realised on the basis of desktop videoconferences. But the problems are also obvious: the necessity of additional hardware and the elevated demands for channel bandwidth. Because of the latter, the use of asynchronous tel...

Asynchronous stream processing with S-Net

NARCIS (Netherlands)

Grelck, C.; Scholz, S.-B.; Shafarenko, A.

2010-01-01

We present the rationale and design of S-Net, a coordination language for asynchronous stream processing. The language achieves a near-complete separation between the application code, written in any conventional programming language, and the coordination/communication code written in S-Net. Our

Using Television Sitcoms to Facilitate Asynchronous Discussions in the Online Communication Course

Science.gov (United States)

Tolman, Elizabeth; Asbury, Bryan

2012-01-01

Asynchronous discussions are a useful instructional resource in the online communication course. In discussion groups students have the opportunity to actively participate and interact with students and the instructor. Asynchronous communication allows for flexibility because "participants can interact with significant amounts of time between…

An asynchronous data-driven event-building scheme based on ATM switching fabrics

International Nuclear Information System (INIS)

Letheren, M.; Christiansen, J.; Mandjavidze, I.; Verhille, H.; De Prycker, M.; Pauwels, B.; Petit, G.; Wright, S.; Lumley, J.

1994-01-01

The very high data rates expected in experiments at the next generation of high luminosity hadron colliders will be handled by pipelined front-end readout electronics and multiple levels (2 or 3) of triggering. A variety of data acquisition architectures have been proposed for use downstream of the first level trigger. Depending on the architecture, the aggregate bandwidths required for event building are expected to be of the order 10--100 Gbit/s. Here, an Asynchronous Transfer Mode (ATM) packet-switching network technology is proposed as the interconnect for building high-performance, scalable data acquisition architectures. This paper introduces the relevant characteristics of ATM and describes components for the construction of an ATM-based event builder: (1) a multi-path, self-routing, scalable ATM switching fabric, (2) an experimental high performance workstation ATM-interface, and (3) a VMEbus ATM-interface. The requirement for traffic shaping in ATM-based event-builders is discussed and an analysis of the performance of several such schemes is presented

Bounding the expected number of rectilinear full Steiner trees

DEFF Research Database (Denmark)

Wulff-Nilsen, Christian

2010-01-01

the expected number of FSTs satisfying simple necessary conditions for being part of an optimal solution. More specifically, we show that the expected number of FSTs spanning exactly K terminals and satisfying the empty lune property, a weak version of the bottleneck property, and the so-called empty hyperbox...... terminals and satisfying the empty lune property and the so-called disjoint lunes property is O(nK). © 2009 Wiley Periodicals, Inc....

[Cost-effectiveness of Synchronous vs. Asynchronous Telepsychiatry in Prison Inmates With Depression].

Science.gov (United States)

Barrera-Valencia, Camilo; Benito-Devia, Alexis Vladimir; Vélez-Álvarez, Consuelo; Figueroa-Barrera, Mario; Franco-Idárraga, Sandra Milena

Telepsychiatry is defined as the use of information and communication technology (ICT) in providing remote psychiatric services. Telepsychiatry is applied using two types of communication: synchronous (real time) and asynchronous (store and forward). To determine the cost-effectiveness of a synchronous and an asynchronous telepsychiatric model in prison inmate patients with symptoms of depression. A cost-effectiveness study was performed on a population consisting of 157 patients from the Establecimiento Penitenciario y Carcelario de Mediana Seguridad de Manizales, Colombia. The sample was determined by applying Zung self-administered surveys for depression (1965) and the Hamilton Depression Rating Scale (HDRS), the latter being the tool used for the comparison. Initial Hamilton score, arrival time, duration of system downtime, and clinical effectiveness variables had normal distributions (P>.05). There were significant differences (P<.001) between care costs for the different models, showing that the mean cost of the asynchronous model is less than synchronous model, and making the asynchronous model more cost-effective. The asynchronous model is the most cost-effective model of telepsychiatry care for patients with depression admitted to a detention centre, according to the results of clinical effectiveness, cost measurement, and patient satisfaction. Copyright © 2016 Asociación Colombiana de Psiquiatría. Publicado por Elsevier España. All rights reserved.

Electronic Reading and Digital Library Technologies: Understanding Learner Expectation and Usage Intent for Mobile Learning

Science.gov (United States)

Hyman, Jack A.; Moser, Mary T.; Segala, Laura N.

2014-01-01

Mobile information technology is changing the education landscape by offering learners the opportunity to engage in asynchronous, ubiquitous instruction. While there is a proliferation of mobile content management systems being developed for the mobile Web and stand-alone mobile applications, few studies have addressed learner expectations and…

ZONES OF STEADY CAPACITOR EXCITATION IN A MODE OF GENERATION OF TYPICAL ASYNCHRONOUS MACHINES

Directory of Open Access Journals (Sweden)

Postoronca Sv.

2009-12-01

Full Text Available In work some features of a mode of capacitor excitation of industrial asynchronous electric motors, and also generators made on their base which can be used in wind installations of low power are considered. Borders of zones of steady capacitor excitation of asynchronous electric motors in rated power of 0,25-22,0 kW and generators made on their base, and also character of influence of own losses and active capacity of loading of the equivalent circuit of the asynchronous machine resulted in parameters have been determined. Some recommendations after maintenance of stability of capacitor excitation of asynchronous machines for work in a mode of generation of electric energy are given.

Gigabit Ethernet signal transmission using asynchronous optical code division multiple access.

Science.gov (United States)

Ma, Philip Y; Fok, Mable P; Shastri, Bhavin J; Wu, Ben; Prucnal, Paul R

2015-12-15

We propose and experimentally demonstrate a novel architecture for interfacing and transmitting a Gigabit Ethernet (GbE) signal using asynchronous incoherent optical code division multiple access (OCDMA). This is the first such asynchronous incoherent OCDMA system carrying GbE data being demonstrated to be working among multi-users where each user is operating with an independent clock/data rate and is granted random access to the network. Three major components, the GbE interface, the OCDMA transmitter, and the OCDMA receiver are discussed in detail. The performance of the system is studied and characterized through measuring eye diagrams, bit-error rate and packet loss rate in real-time file transfer. Our Letter also addresses the near-far problem and realizes asynchronous transmission and detection of signal.

Asynchronous vs didactic education: it's too early to throw in the towel on tradition.

Science.gov (United States)

Jordan, Jaime; Jalali, Azadeh; Clarke, Samuel; Dyne, Pamela; Spector, Tahlia; Coates, Wendy

2013-08-08

Asynchronous, computer based instruction is cost effective, allows self-directed pacing and review, and addresses preferences of millennial learners. Current research suggests there is no significant difference in learning compared to traditional classroom instruction. Data are limited for novice learners in emergency medicine. The objective of this study was to compare asynchronous, computer-based instruction with traditional didactics for senior medical students during a week-long intensive course in acute care. We hypothesized both modalities would be equivalent. This was a prospective observational quasi-experimental study of 4th year medical students who were novice learners with minimal prior exposure to curricular elements. We assessed baseline knowledge with an objective pre-test. The curriculum was delivered in either traditional lecture format (shock, acute abdomen, dyspnea, field trauma) or via asynchronous, computer-based modules (chest pain, EKG interpretation, pain management, trauma). An interactive review covering all topics was followed by a post-test. Knowledge retention was measured after 10 weeks. Pre and post-test items were written by a panel of medical educators and validated with a reference group of learners. Mean scores were analyzed using dependent t-test and attitudes were assessed by a 5-point Likert scale. 44 of 48 students completed the protocol. Students initially acquired more knowledge from didactic education as demonstrated by mean gain scores (didactic: 28.39% ± 18.06; asynchronous 9.93% ± 23.22). Mean difference between didactic and asynchronous = 18.45% with 95% CI [10.40 to 26.50]; p = 0.0001. Retention testing demonstrated similar knowledge attrition: mean gain scores -14.94% (didactic); -17.61% (asynchronous), which was not significantly different: 2.68% ± 20.85, 95% CI [-3.66 to 9.02], p = 0.399. The attitudinal survey revealed that 60.4% of students believed the asynchronous modules were educational and 95

Unequal Expectations

DEFF Research Database (Denmark)

Karlson, Kristian Bernt

the role of causal inference in social science; and it discusses the potential of the findings of the dissertation to inform educational policy. In Chapters II and III, constituting the substantive contribution of the dissertation, I examine the process through which students form expectations...... of the relation between the self and educational prospects; evaluations that are socially bounded in that students take their family's social position into consideration when forming their educational expectations. One important consequence of this learning process is that equally talented students tend to make...... for their educational futures. Focusing on the causes rather than the consequences of educational expectations, I argue that students shape their expectations in response to the signals about their academic performance they receive from institutionalized performance indicators in schools. Chapter II considers...

Computing by Temporal Order: Asynchronous Cellular Automata

Directory of Open Access Journals (Sweden)

Michael Vielhaber

2012-08-01

Full Text Available Our concern is the behaviour of the elementary cellular automata with state set 0,1 over the cell set Z/nZ (one-dimensional finite wrap-around case, under all possible update rules (asynchronicity. Over the torus Z/nZ (n<= 11,we will see that the ECA with Wolfram rule 57 maps any v in F_2^n to any w in F_2^n, varying the update rule. We furthermore show that all even (element of the alternating group bijective functions on the set F_2^n = 0,...,2^n-1, can be computed by ECA57, by iterating it a sufficient number of times with varying update rules, at least for n <= 10. We characterize the non-bijective functions computable by asynchronous rules.

Computational Aspects of Asynchronous CA

OpenAIRE

Chandesris, Jérôme; Dennunzio, Alberto; Formenti, Enrico; Manzoni, Luca

2011-01-01

This work studies some aspects of the computational power of fully asynchronous cellular automata (ACA). We deal with some notions of simulation between ACA and Turing Machines. In particular, we characterize the updating sequences specifying which are "universal", i.e., allowing a (specific family of) ACA to simulate any TM on any input. We also consider the computational cost of such simulations.

On Time with Minimal Expected Cost!

DEFF Research Database (Denmark)

David, Alexandre; Jensen, Peter Gjøl; Larsen, Kim Guldstrand

2014-01-01

(Priced) timed games are two-player quantitative games involving an environment assumed to be completely antogonistic. Classical analysis consists in the synthesis of strategies ensuring safety, time-bounded or cost-bounded reachability objectives. Assuming a randomized environment, the (priced......) timed game essentially defines an infinite-state Markov (reward) decision proces. In this setting the objective is classically to find a strategy that will minimize the expected reachability cost, but with no guarantees on worst-case behaviour. In this paper, we provide efficient methods for computing...... reachability strategies that will both ensure worst case time-bounds as well as provide (near-) minimal expected cost. Our method extends the synthesis algorithms of the synthesis tool Uppaal-Tiga with suitable adapted reinforcement learning techniques, that exhibits several orders of magnitude improvements w...

The design of an asynchronous Tiny RISC TM/TR4101 microprocessor core

DEFF Research Database (Denmark)

Christensen, Kåre Tais; Jensen, P.; Korger, P.

1998-01-01

This paper presents the design of an asynchronous version of the TR4101 embedded microprocessor core developed by LSI Logic Inc. The asynchronous processor, called ARISC, was designed using the same CAD tools and the same standard cell library that was used to implement the TR4101. The paper repo...

Synchronization of Hierarchical Time-Varying Neural Networks Based on Asynchronous and Intermittent Sampled-Data Control.

Science.gov (United States)

Xiong, Wenjun; Patel, Ragini; Cao, Jinde; Zheng, Wei Xing

In this brief, our purpose is to apply asynchronous and intermittent sampled-data control methods to achieve the synchronization of hierarchical time-varying neural networks. The asynchronous and intermittent sampled-data controllers are proposed for two reasons: 1) the controllers may not transmit the control information simultaneously and 2) the controllers cannot always exist at any time . The synchronization is then discussed for a kind of hierarchical time-varying neural networks based on the asynchronous and intermittent sampled-data controllers. Finally, the simulation results are given to illustrate the usefulness of the developed criteria.In this brief, our purpose is to apply asynchronous and intermittent sampled-data control methods to achieve the synchronization of hierarchical time-varying neural networks. The asynchronous and intermittent sampled-data controllers are proposed for two reasons: 1) the controllers may not transmit the control information simultaneously and 2) the controllers cannot always exist at any time . The synchronization is then discussed for a kind of hierarchical time-varying neural networks based on the asynchronous and intermittent sampled-data controllers. Finally, the simulation results are given to illustrate the usefulness of the developed criteria.

The Thomas-Fermi model: momentum expectation values

International Nuclear Information System (INIS)

Dmitrieva, I.K.; Plindov, G.I.

1983-01-01

Within the Thomas-Fermi model including the exchange interaction and contributions of strongly bound electrons, analytical expressions are obtained for all momentum expectation values and for some of the expectation values of powers of the electron density for an atom with an arbitrary degree of ionization. It is shown that a correct treatment of strongly bound electrons gives a quantitative estimate of and within 3 - 1 expansion coefficients for and are given as an explicit function of the electron number

Experimental evidence for bounds on quantum correlations.

Science.gov (United States)

Bovino, F A; Castagnoli, G; Degiovanni, I P; Castelletto, S

2004-02-13

We implemented the experiment proposed by Cabello in the preceding Letter to test the bounds of quantum correlation. As expected from the theory we found that, for certain choices of local observables, Tsirelson's bound of the Clauser-Horne-Shimony-Holt inequality (2 x square root of 2) is not reached by any quantum states.

Towards behavioral synthesis of asynchronous circuits - an implementation template targeting syntax directed compilation

DEFF Research Database (Denmark)

Nielsen, Sune Fallgaard; Sparsø, Jens; Madsen, Jan

2004-01-01

This paper presents a method for behavioral synthesis of asynchronous circuits. Our approach aims at providing a synthesis flow which is very similar to what is found in existing synchronous design tools. We adapt the synchronous behavioral synthesis abstraction into the asynchronous handshake...

FAST: A fully asynchronous and status-tracking pattern for geoprocessing services orchestration

Science.gov (United States)

Wu, Huayi; You, Lan; Gui, Zhipeng; Gao, Shuang; Li, Zhenqiang; Yu, Jingmin

2014-09-01

Geoprocessing service orchestration (GSO) provides a unified and flexible way to implement cross-application, long-lived, and multi-step geoprocessing service workflows by coordinating geoprocessing services collaboratively. Usually, geoprocessing services and geoprocessing service workflows are data and/or computing intensive. The intensity feature may make the execution process of a workflow time-consuming. Since it initials an execution request without blocking other interactions on the client side, an asynchronous mechanism is especially appropriate for GSO workflows. Many critical problems remain to be solved in existing asynchronous patterns for GSO including difficulties in improving performance, status tracking, and clarifying the workflow structure. These problems are a challenge when orchestrating performance efficiency, making statuses instantly available, and constructing clearly structured GSO workflows. A Fully Asynchronous and Status-Tracking (FAST) pattern that adopts asynchronous interactions throughout the whole communication tier of a workflow is proposed for GSO. The proposed FAST pattern includes a mechanism that actively pushes the latest status to clients instantly and economically. An independent proxy was designed to isolate the status tracking logic from the geoprocessing business logic, which assists the formation of a clear GSO workflow structure. A workflow was implemented in the FAST pattern to simulate the flooding process in the Poyang Lake region. Experimental results show that the proposed FAST pattern can efficiently tackle data/computing intensive geoprocessing tasks. The performance of all collaborative partners was improved due to the asynchronous mechanism throughout communication tier. A status-tracking mechanism helps users retrieve the latest running status of a GSO workflow in an efficient and instant way. The clear structure of the GSO workflow lowers the barriers for geospatial domain experts and model designers to

Embedded Vehicle Speed Estimation System Using an Asynchronous Temporal Contrast Vision Sensor

Directory of Open Access Journals (Sweden)

D. Bauer

2007-01-01

Full Text Available This article presents an embedded multilane traffic data acquisition system based on an asynchronous temporal contrast vision sensor, and algorithms for vehicle speed estimation developed to make efficient use of the asynchronous high-precision timing information delivered by this sensor. The vision sensor features high temporal resolution with a latency of less than 100 μs, wide dynamic range of 120 dB of illumination, and zero-redundancy, asynchronous data output. For data collection, processing and interfacing, a low-cost digital signal processor is used. The speed of the detected vehicles is calculated from the vision sensor's asynchronous temporal contrast event data. We present three different algorithms for velocity estimation and evaluate their accuracy by means of calibrated reference measurements. The error of the speed estimation of all algorithms is near zero mean and has a standard deviation better than 3% for both traffic flow directions. The results and the accuracy limitations as well as the combined use of the algorithms in the system are discussed.

Pediatric emergency medicine asynchronous e-learning: a multicenter randomized controlled Solomon four-group study.

Science.gov (United States)

Chang, Todd P; Pham, Phung K; Sobolewski, Brad; Doughty, Cara B; Jamal, Nazreen; Kwan, Karen Y; Little, Kim; Brenkert, Timothy E; Mathison, David J

2014-08-01

Asynchronous e-learning allows for targeted teaching, particularly advantageous when bedside and didactic education is insufficient. An asynchronous e-learning curriculum has not been studied across multiple centers in the context of a clinical rotation. We hypothesize that an asynchronous e-learning curriculum during the pediatric emergency medicine (EM) rotation improves medical knowledge among residents and students across multiple participating centers. Trainees on pediatric EM rotations at four large pediatric centers from 2012 to 2013 were randomized in a Solomon four-group design. The experimental arms received an asynchronous e-learning curriculum consisting of nine Web-based, interactive, peer-reviewed Flash/HTML5 modules. Postrotation testing and in-training examination (ITE) scores quantified improvements in knowledge. A 2 × 2 analysis of covariance (ANCOVA) tested interaction and main effects, and Pearson's correlation tested associations between module usage, scores, and ITE scores. A total of 256 of 458 participants completed all study elements; 104 had access to asynchronous e-learning modules, and 152 were controls who used the current education standards. No pretest sensitization was found (p = 0.75). Use of asynchronous e-learning modules was associated with an improvement in posttest scores (p effect (partial η(2) = 0.19). Posttest scores correlated with ITE scores (r(2) = 0.14, p e-learning is an effective educational tool to improve knowledge in a clinical rotation. Web-based asynchronous e-learning is a promising modality to standardize education among multiple institutions with common curricula, particularly in clinical rotations where scheduling difficulties, seasonality, and variable experiences limit in-hospital learning. © 2014 by the Society for Academic Emergency Medicine.

Increasing Student Engagement Using Asynchronous Learning

Science.gov (United States)

Northey, Gavin; Bucic, Tania; Chylinski, Mathew; Govind, Rahul

2015-01-01

Student engagement is an ongoing concern for educators because of its positive association with deep learning and educational outcomes. This article tests the use of a social networking site (Facebook) as a tool to facilitate asynchronous learning opportunities that complement face-to-face interactions and thereby enable a stronger learning…

Asynchronous Gossip for Averaging and Spectral Ranking

Science.gov (United States)

Borkar, Vivek S.; Makhijani, Rahul; Sundaresan, Rajesh

2014-08-01

We consider two variants of the classical gossip algorithm. The first variant is a version of asynchronous stochastic approximation. We highlight a fundamental difficulty associated with the classical asynchronous gossip scheme, viz., that it may not converge to a desired average, and suggest an alternative scheme based on reinforcement learning that has guaranteed convergence to the desired average. We then discuss a potential application to a wireless network setting with simultaneous link activation constraints. The second variant is a gossip algorithm for distributed computation of the Perron-Frobenius eigenvector of a nonnegative matrix. While the first variant draws upon a reinforcement learning algorithm for an average cost controlled Markov decision problem, the second variant draws upon a reinforcement learning algorithm for risk-sensitive control. We then discuss potential applications of the second variant to ranking schemes, reputation networks, and principal component analysis.

Violation of the equivalence principle for stressed bodies in asynchronous relativity

Energy Technology Data Exchange (ETDEWEB)

Andrade Martins, R. de (Centro de Logica, Epistemologia e Historia da Ciencia, Campinas (Brazil))

1983-12-11

In the recently developed asynchronous formulation of the relativistic theory of extended bodies, the inertial mass of a body does not explicitly depend on its pressure or stress. The detailed analysis of the weight of a box filled with a gas and placed in a weak gravitational field shows that this feature of asynchronous relativity implies a breakdown of the equivalence between inertial and passive gravitational mass for stressed systems.

On the theoretical gap between synchronous and asynchronous MPC protocols

DEFF Research Database (Denmark)

Beerliová-Trubíniová, Zuzana; Hirt, Martin; Nielsen, Jesper Buus

2010-01-01

that in the cryptographic setting (with setup), the sole reason for it is the distribution of inputs: given an oracle for input distribution, cryptographically-secure asynchronous MPC is possible with the very same condition as synchronous MPC, namely t ..., we show that such an input-distribution oracle can be reduced to an oracle that allows each party to synchronously broadcast one single message. This means that when one single round of synchronous broadcast is available, then asynchronous MPC is possible at the same condition as synchronous MPC...

Novel Simplified Model for Asynchronous Machine with Consideration of Frequency Characteristic

Directory of Open Access Journals (Sweden)

Changchun Cai

2014-01-01

Full Text Available The frequency characteristic of electric equipment should be considered in the digital simulation of power systems. The traditional asynchronous machine third-order transient model excludes not only the stator transient but also the frequency characteristics, thus decreasing the application sphere of the model and resulting in a large error under some special conditions. Based on the physical equivalent circuit and Park model for asynchronous machines, this study proposes a novel asynchronous third-order transient machine model with consideration of the frequency characteristic. In the new definitions of variables, the voltages behind the reactance are redefined as the linear equation of flux linkage. In this way, the rotor voltage equation is not associated with the derivative terms of frequency. However, the derivative terms of frequency should not always be ignored in the application of the traditional third-order transient model. Compared with the traditional third-order transient model, the novel simplified third-order transient model with consideration of the frequency characteristic is more accurate without increasing the order and complexity. Simulation results show that the novel third-order transient model for the asynchronous machine is suitable and effective and is more accurate than the widely used traditional simplified third-order transient model under some special conditions with drastic frequency fluctuations.

Asynchronous Multiparty Computation

DEFF Research Database (Denmark)

Damgård, Ivan Bjerre; Geisler, Martin; Krøigaard, Mikkel

2009-01-01

guarantees termination if the adversary allows a preprocessing phase to terminate, in which no information is released. The communication complexity of this protocol is the same as that of a passively secure solution up to a constant factor. It is secure against an adaptive and active adversary corrupting...... less than n/3 players. We also present a software framework for implementation of asynchronous protocols called VIFF (Virtual Ideal Functionality Framework), which allows automatic parallelization of primitive operations such as secure multiplications, without having to resort to complicated...... multithreading. Benchmarking of a VIFF implementation of our protocol confirms that it is applicable to practical non-trivial secure computations....

Argo: A Time-Elastic Time-Division-Multiplexed NOC using Asynchronous Routers

DEFF Research Database (Denmark)

Kasapaki, Evangelia; Sparsø, Jens

2014-01-01

are either synchronous or mesochronous. We use asynchronous routers to achieve a simpler, smaller, and more robust, self-timed design. Our design exploits the fact that pipelined asynchronous circuits also behave as ripple FIFOs. Thus, it avoids the need for explicit synchronization FIFOs between the routers......In this paper we explore the use of asynchronous routers in a time-division-multiplexed (TDM) network-on-chip (NOC), Argo, that is being developed for a multi-processor platform for hard real-time systems. TDM inherently requires a common time reference, and existing TDM-based NOC designs...... delays derived from a 65nm CMOS implementation, a worstcase analysis shows that a typical design can tolerate a skew of 1-5 cycles (depending on FIFO depths and NI clock frequency). Simulation results of a 2 x 2 NOC confirm this....

Asynchronous vs didactic education: it’s too early to throw in the towel on tradition

Science.gov (United States)

2013-01-01

Background Asynchronous, computer based instruction is cost effective, allows self-directed pacing and review, and addresses preferences of millennial learners. Current research suggests there is no significant difference in learning compared to traditional classroom instruction. Data are limited for novice learners in emergency medicine. The objective of this study was to compare asynchronous, computer-based instruction with traditional didactics for senior medical students during a week-long intensive course in acute care. We hypothesized both modalities would be equivalent. Methods This was a prospective observational quasi-experimental study of 4th year medical students who were novice learners with minimal prior exposure to curricular elements. We assessed baseline knowledge with an objective pre-test. The curriculum was delivered in either traditional lecture format (shock, acute abdomen, dyspnea, field trauma) or via asynchronous, computer-based modules (chest pain, EKG interpretation, pain management, trauma). An interactive review covering all topics was followed by a post-test. Knowledge retention was measured after 10 weeks. Pre and post-test items were written by a panel of medical educators and validated with a reference group of learners. Mean scores were analyzed using dependent t-test and attitudes were assessed by a 5-point Likert scale. Results 44 of 48 students completed the protocol. Students initially acquired more knowledge from didactic education as demonstrated by mean gain scores (didactic: 28.39% ± 18.06; asynchronous 9.93% ± 23.22). Mean difference between didactic and asynchronous = 18.45% with 95% CI [10.40 to 26.50]; p = 0.0001. Retention testing demonstrated similar knowledge attrition: mean gain scores −14.94% (didactic); -17.61% (asynchronous), which was not significantly different: 2.68% ± 20.85, 95% CI [−3.66 to 9.02], p = 0.399. The attitudinal survey revealed that 60.4% of students believed the asynchronous

An Evaluation of Parallel Synchronous and Conservative Asynchronous Logic-Level Simulations

Directory of Open Access Journals (Sweden)

Ausif Mahmood

1996-01-01

a circuit remain fixed during the entire simulation. We remove this limitation and, by extending the analyses to multi-input, multi-output circuits with an arbitrary number of input events, show that the conservative asynchronous simulation extracts more parallelism and executes faster than synchronous simulation in general. Our conclusions are supported by a comparison of the idealized execution times of synchronous and conservative asynchronous algorithms on ISCAS combinational and sequential benchmark circuits.

Psychophysiological effects of synchronous versus asynchronous music during cycling.

Science.gov (United States)

Lim, Harry B T; Karageorghis, Costas I; Romer, Lee M; Bishop, Daniel T

2014-02-01

Synchronizing movement to a musical beat may reduce the metabolic cost of exercise, but findings to date have been equivocal. Our aim was to examine the degree to which the synchronous application of music moderates the metabolic demands of a cycle ergometer task. Twenty-three recreationally active men made two laboratory visits. During the first visit, participants completed a maximal incremental ramp test on a cycle ergometer. At the second visit, they completed four randomized 6-min cycling bouts at 90% of ventilatory threshold (control, metronome, synchronous music, and asynchronous music). Main outcome variables were oxygen uptake, HR, ratings of dyspnea and limb discomfort, affective valence, and arousal. No significant differences were evident for oxygen uptake. HR was lower under the metronome condition (122 ± 15 bpm) compared to asynchronous music (124 ± 17 bpm) and control (125 ± 16 bpm). Limb discomfort was lower while listening to the metronome (2.5 ± 1.2) and synchronous music (2.3 ± 1.1) compared to control (3.0 ± 1.5). Both music conditions, synchronous (1.9 ± 1.2) and asynchronous (2.1 ± 1.3), elicited more positive affective valence compared to metronome (1.2 ± 1.4) and control (1.2 ± 1.2), while arousal was higher with synchronous music (3.4 ± 0.9) compared to metronome (2.8 ± 1.0) and control (2.8 ± 0.9). Synchronizing movement to a rhythmic stimulus does not reduce metabolic cost but may lower limb discomfort. Moreover, synchronous music has a stronger effect on limb discomfort and arousal when compared to asynchronous music.

Can the Σ-nn system be bound?

International Nuclear Information System (INIS)

Stadler, A.; Gibson, B.F.

1994-01-01

Motivated by the Σ-hypernuclear states reported in (K - ,π ± ) experiments, we have explored the possibility that there exists a particle-stable Σ - nn bound state. For the Juelich A hyperon-nucleon, realistic-force model, our calculations yield little reason to expect a positive-parity bound state or resonance in either the J=1/2 or the J=3/2 channels

Emphasis on the Impact of Asynchronous Media

African Journals Online (AJOL)

ICTs and their utilization is one of the most pertinent issues in the education industry today. ... The paper pointed out specific impact of asynchronous ICT media in ... The paper finally noted that the struggle to be part of the digital world is ...

Heating calculation features at self-start of large asynchronous motor

Science.gov (United States)

Shevchenko, A. A.; Temlyakova, Z. S.; Grechkin, V. V.; Vilberger, M. E.

2017-10-01

The article proposes a method for optimizing the incremental heating calculation in the active volume of a large asynchronous motor for certain kinds of load characteristics. The incremental heating calculation is conditioned by the need to determine the aging level of the insulation and to predict a decrease in the electric machine service life. The method for optimizing the incremental heating calculation of asynchronous motor active volume is based on the automation of calculating the heating when simulating the self-starting process of the motor after eliminating an AC drop.

Design issues in the semantics and scheduling of asynchronous tasks.

Energy Technology Data Exchange (ETDEWEB)

Olivier, Stephen L.

2013-07-01

The asynchronous task model serves as a useful vehicle for shared memory parallel programming, particularly on multicore and manycore processors. As adoption of model among programmers has increased, support has emerged for the integration of task parallel language constructs into mainstream programming languages, e.g., C and C++. This paper examines some of the design decisions in Cilk and OpenMP concerning semantics and scheduling of asynchronous tasks with the aim of informing the efforts of committees considering language integration, as well as developers of new task parallel languages and libraries.

UNIVERSAL REGULAR AUTONOMOUS ASYNCHRONOUS SYSTEMS: ω-LIMIT SETS, INVARIANCE AND BASINS OF ATTRACTION

Directory of Open Access Journals (Sweden)

Serban Vlad

2011-07-01

Full Text Available The asynchronous systems are the non-deterministic real timebinarymodels of the asynchronous circuits from electrical engineering.Autonomy means that the circuits and their models have no input.Regularity means analogies with the dynamical systems, thus such systems may be considered to be real time dynamical systems with a’vector field’, Universality refers to the case when the state space of the system is the greatest possible in the sense of theinclusion. The purpose of this paper is that of defining, by analogy with the dynamical systems theory, the omega-limit sets, the invariance and the basins of attraction of the universal regular autonomous asynchronous systems.

A novel asynchronous access method with binary interfaces

Directory of Open Access Journals (Sweden)

Torres-Solis Jorge

2008-10-01

Full Text Available Abstract Background Traditionally synchronous access strategies require users to comply with one or more time constraints in order to communicate intent with a binary human-machine interface (e.g., mechanical, gestural or neural switches. Asynchronous access methods are preferable, but have not been used with binary interfaces in the control of devices that require more than two commands to be successfully operated. Methods We present the mathematical development and evaluation of a novel asynchronous access method that may be used to translate sporadic activations of binary interfaces into distinct outcomes for the control of devices requiring an arbitrary number of commands to be controlled. With this method, users are required to activate their interfaces only when the device under control behaves erroneously. Then, a recursive algorithm, incorporating contextual assumptions relevant to all possible outcomes, is used to obtain an informed estimate of user intention. We evaluate this method by simulating a control task requiring a series of target commands to be tracked by a model user. Results When compared to a random selection, the proposed asynchronous access method offers a significant reduction in the number of interface activations required from the user. Conclusion This novel access method offers a variety of advantages over traditionally synchronous access strategies and may be adapted to a wide variety of contexts, with primary relevance to applications involving direct object manipulation.

NUMERICAL WITHOUT ITERATION METHOD OF MODELING OF ELECTROMECHANICAL PROCESSES IN ASYNCHRONOUS ENGINES

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D. G. Patalakh

2018-02-01

Full Text Available Purpose. Development of calculation of electromagnetic and electromechanic transients is in asynchronous engines without iterations. Methodology. Numeral methods of integration of usual differential equations, programming. Findings. As the system of equations, describing the dynamics of asynchronous engine, contents the products of rotor and stator currents and product of rotation frequency of rotor and currents, so this system is nonlinear one. The numeral solution of nonlinear differential equations supposes an iteration process on every step of integration. Time-continuing and badly converging iteration process may be the reason of calculation slowing. The improvement of numeral method by the way of an iteration process removing is offered. As result the modeling time is reduced. The improved numeral method is applied for integration of differential equations, describing the dynamics of asynchronous engine. Originality. The improvement of numeral method allowing to execute numeral integrations of differential equations containing product of functions is offered, that allows to avoid an iteration process on every step of integration and shorten modeling time. Practical value. On the basis of the offered methodology the universal program of modeling of electromechanics processes in asynchronous engines could be developed as taking advantage on fast-acting.

Dynamic Performances of Asynchronous Machines | Ubeku ...

African Journals Online (AJOL)

The per-phase parameters of a 1.5 hp, 380 V, 50 Hz, 4 poles, 3 phase asynchronous machine used in the simulation were computed with reading obtained from a dc, no-load and blocked rotor tests carried out on the machine in the laboratory. The results obtained from the computer simulations confirmed the capabilities ...

THE ROLE OF OFFLINE METALANGUAGE TALK IN ASYNCHRONOUS COMPUTER-MEDIATED COMMUNICATION

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Keiko Kitade

2008-02-01

Full Text Available In order to demonstrate how learners utilize the text-based asynchronous attributes of the Bulletin Board System, this study explored Japanese-as-a-second-language learners' metalanguage episodes (Swain & Lapkin, 1995, 1998 in offline verbal peer speech and online asynchronous discussions with their Japanese key pals. The findings suggest the crucial role of offline collaborative dialogue, the interactional modes in which the episodes occur, and the unique discourse structure of metalanguage episodes concerning online and offline interactions. A high score on the posttest also suggests the high retention of linguistic knowledge constructed through offline peer dialogue. In the offline mode, the learners were able to collaboratively construct knowledge with peers in the stipulated time, while simultaneously focusing on task content in the online interaction. The retrospective interviews and questionnaires reveal the factors that could affect the benefits of the asynchronous computer-mediated communication medium for language learning.

Determination of power and moment on shaft of special asynchronous electric drives

Science.gov (United States)

Karandey, V. Yu; Popov, B. K.; Popova, O. B.; Afanasyev, V. L.

2018-03-01

In the article, questions and tasks of determination of power and the moment on a shaft of special asynchronous electric drives are considered. Use of special asynchronous electric drives in mechanical engineering and other industries is relevant. The considered types of electric drives possess the improved mass-dimensional indicators in comparison with singleengine systems. Also these types of electric drives have constructive advantages; the improved characteristics allow one to realize the technological process. But creation and design of new electric drives demands adjustment of existing or development of new methods and approaches of calculation of parameters. Determination of power and the moment on a shaft of special asynchronous electric drives is the main objective during design of electric drives. This task has been solved based on a method of electromechanical transformation of energy.

Methodological Reflections on the Use of Asynchronous Online Focus Groups in Health Research

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Sarah Williams PhD

2012-09-01

Full Text Available The Internet is increasingly used as a tool in qualitative research. In particular, asynchronous online focus groups are used when factors such as cost, time, or access to participants can make conducting face-to-face research difficult. In this article we consider key methodological issues involved in using asynchronous online focus groups to explore experiences of health and illness. The written nature of Internet communication, the lack of physical presence, and the asynchronous, longitudinal aspects enable participants who might not normally contribute to research studies to reflect on their personal stories before disclosing them to the researcher. Implications for study design, recruitment strategies, and ethics should be considered when deciding whether to use this method.

Aspects of computation on asynchronous parallel processors

International Nuclear Information System (INIS)

Wright, M.

1989-01-01

The increasing availability of asynchronous parallel processors has provided opportunities for original and useful work in scientific computing. However, the field of parallel computing is still in a highly volatile state, and researchers display a wide range of opinion about many fundamental questions such as models of parallelism, approaches for detecting and analyzing parallelism of algorithms, and tools that allow software developers and users to make effective use of diverse forms of complex hardware. This volume collects the work of researchers specializing in different aspects of parallel computing, who met to discuss the framework and the mechanics of numerical computing. The far-reaching impact of high-performance asynchronous systems is reflected in the wide variety of topics, which include scientific applications (e.g. linear algebra, lattice gauge simulation, ordinary and partial differential equations), models of parallelism, parallel language features, task scheduling, automatic parallelization techniques, tools for algorithm development in parallel environments, and system design issues

An Asynchronous IEEE Floating-Point Arithmetic Unit

Directory of Open Access Journals (Sweden)

Joel R. Noche

2007-12-01

Full Text Available An asynchronous floating-point arithmetic unit is designed and tested at the transistor level usingCadence software. It uses CMOS (complementary metal oxide semiconductor and DCVS (differentialcascode voltage switch logic in a 0.35 µm process using a 3.3 V supply voltage, with dual-rail data andsingle-rail control signals using four-phase handshaking.Using 17,085 transistors, the unit handles single-precision (32-bit addition/subtraction, multiplication,division, and remainder using the IEEE 754-1985 Standard for Binary Floating-Point Arithmetic, withrounding and other operations to be handled by separate hardware or software. Division and remainderare done using a restoring subtractive algorithm; multiplication uses an additive algorithm. Exceptionsare noted by flags (and not trap handlers and the output is in single-precision.Previous work on asynchronous floating-point arithmetic units have mostly focused on single operationssuch as division. This is the first work to the authors' knowledge that can perform floating-point addition,multiplication, division, and remainder using a common datapath.

Regression analysis of sparse asynchronous longitudinal data.

Science.gov (United States)

Cao, Hongyuan; Zeng, Donglin; Fine, Jason P

2015-09-01

We consider estimation of regression models for sparse asynchronous longitudinal observations, where time-dependent responses and covariates are observed intermittently within subjects. Unlike with synchronous data, where the response and covariates are observed at the same time point, with asynchronous data, the observation times are mismatched. Simple kernel-weighted estimating equations are proposed for generalized linear models with either time invariant or time-dependent coefficients under smoothness assumptions for the covariate processes which are similar to those for synchronous data. For models with either time invariant or time-dependent coefficients, the estimators are consistent and asymptotically normal but converge at slower rates than those achieved with synchronous data. Simulation studies evidence that the methods perform well with realistic sample sizes and may be superior to a naive application of methods for synchronous data based on an ad hoc last value carried forward approach. The practical utility of the methods is illustrated on data from a study on human immunodeficiency virus.

An Asynchronous Circuit Design Technique for a Flexible 8-Bit Microprocessor

Science.gov (United States)

Karaki, Nobuo; Nanmoto, Takashi; Inoue, Satoshi

This paper presents an asynchronous design technique, an enabler for the emerging technology of flexible microelectronics that feature low-temperature processed polysilicon (LTPS) thin-film transistors (TFT) and surface-free technology by laser annealing/ablation (SUFTLA®). The first design instance chosen is an 8-bit microprocessor. LTPS TFTs are good for realizing displays having integrated VLSI circuit at lower costs. However, LTPS TFTs have drawbacks, including substantial deviations in characteristics and the self-heating phenomenon. To solve these problems, the authors adopted the asynchronous circuit design technique and developed an asynchronous design language called Verilog+, which is based on a subset of Verilog HDL® and includes minimal primitives used for describing the communications between modules, and the dedicated tools including a translator called xlator and a synthesizer called ctrlsyn. The flexible 8-bit microprocessor stably operates at 500kHz, drawing 180μA from a 5V power source. The microprocessor's electromagnetic emissions are 21dB less than those of the synchronous counterpart.

Pseudo Asynchronous Level Crossing adc for ecg Signal Acquisition.

Science.gov (United States)

Marisa, T; Niederhauser, T; Haeberlin, A; Wildhaber, R A; Vogel, R; Goette, J; Jacomet, M

2017-02-07

A new pseudo asynchronous level crossing analogue-to-digital converter (adc) architecture targeted for low-power, implantable, long-term biomedical sensing applications is presented. In contrast to most of the existing asynchronous level crossing adc designs, the proposed design has no digital-to-analogue converter (dac) and no continuous time comparators. Instead, the proposed architecture uses an analogue memory cell and dynamic comparators. The architecture retains the signal activity dependent sampling operation by generating events only when the input signal is changing. The architecture offers the advantages of smaller chip area, energy saving and fewer analogue system components. Beside lower energy consumption the use of dynamic comparators results in a more robust performance in noise conditions. Moreover, dynamic comparators make interfacing the asynchronous level crossing system to synchronous processing blocks simpler. The proposed adc was implemented in [Formula: see text] complementary metal-oxide-semiconductor (cmos) technology, the hardware occupies a chip area of 0.0372 mm 2 and operates from a supply voltage of [Formula: see text] to [Formula: see text]. The adc's power consumption is as low as 0.6 μW with signal bandwidth from [Formula: see text] to [Formula: see text] and achieves an equivalent number of bits (enob) of up to 8 bits.

Asynchronous versus Synchronous Learning in Pharmacy Education

Science.gov (United States)

Motycka, Carol A.; St. Onge, Erin L.; Williams, Jennifer

2013-01-01

Objective: To better understand the technology being used today in pharmacy education through a review of the current methodologies being employed at various institutions. Also, to discuss the benefits and difficulties of asynchronous and synchronous methodologies, which are being utilized at both traditional and distance education campuses.…

Proximity effect tunneling into virtual bound state alloys

International Nuclear Information System (INIS)

Tang, I.M.; Roongkkeadsakoon, S.

1984-01-01

The effects of a narrow virtual bound state formed by transition metal impurities dissolved in the normal layer of a superconducting proximity effect sandwich are studied. Using standard renormalization techniques, we obtain the changes in the transition temperatures and the jumps in the specific heat at T/sub c/ as a function of the thickness of the normal layer, of the widths of the virtual bound states, and of the impurity concentrations. It is seen that narrow virtual bound states lead to decrease in the transition temperatures, while broad virtual bound states do not. It if further seen that the narrow virtual bound state causes the reduced specific heat jump at T/sub c/ to deviate from the BCS behavior expected of the pure sandwich

Performance Studies for Protection Against Asynchronous Dumps in the LHC

CERN Document Server

Kramer, T; Bracco, C; Goddard, B; Meddahi, M

2010-01-01

The LHC beam dump system has to safely dispose all beams in a wide energy range of 450 GeV to 7 TeV. A 3 ms abort gap in the beam structure for the switch-on of the extraction kicker field ideally allows a loss-free extraction under normal operating conditions. However, a low number of asynchronous beam aborts is to be expected from reliability calculations and from the first year's operational experience with the beam dump kickers. For such cases, MAD-X simulations including all optics and alignment errors have been performed to determine loss patterns around the LHC as a function of the position of the main protection elements in interaction region six. Special attention was paid to the beam load on the tungsten collimators which protect the triplets in the LHC experimental insertions, and the tracking results compared with semi-analytical numerical estimates. The simulations are also compared to the results of beam commissioning of these protection devices.

Asynchronous learning: student utilization out of sync with their preference

Directory of Open Access Journals (Sweden)

Edward K. Lew

2016-06-01

Full Text Available Background: Asynchronous learning is gaining popularity. Data are limited regarding this learning method in medical students rotating in emergency medicine (EM. In EM, faculty time is limited to give in-person lectures. The authors sought to create an online curriculum that students could utilize as an additional learning modality. Objective: The goal was to evaluate effectiveness, participation, and preference for this mode of learning. Methods: We developed five online, narrated PowerPoint presentations. After orientation, access to the online curriculum was provided to the students, which they could review at their leisure. Results: One hundred and seven fourth-year medical students participated. They reported the curriculum to be of high quality. Pretest scores were similar for those that viewed all lectures – compliant group (CG (9.5 [CI 4.8–14.1] and those that did not view any – non-compliant group (NCG (9.6 [CI 5.9–13.4]. There was no statistical significant difference in posttest scores between the groups although there was improvement overall: CG 14.6 (CI 6.9–22.1; NCG 11.4 (CI 5.7–17.1. A majority (69.2% favored inclusion of asynchronous learning, but less than a quarter (22.4% reported viewing all five modules and more than a third (36.4% viewed none. Conclusion: Despite student-expressed preference for an online curriculum, they used the online resource less than expected. This should give pause to educators looking to convert core EM topics to an online format. However, when high-quality online lectures are utilized as a learning tool, this study demonstrates that they had neither a positive nor a negative impact on test scores.

Asynchronous Free-Space Optical CDMA Communications System for Last-mile Access Network

DEFF Research Database (Denmark)

Jurado-Navas, Antonio; Raddo, Thiago R.; Sanches, Anderson L.

2016-01-01

We propose a new hybrid asynchronous OCDMA-FSO communications system for access network solutions. New ABER expressions are derived under gamma-gamma scintillation channels, where all users can surprisingly achieve error-free transmissions when FEC is employed.......We propose a new hybrid asynchronous OCDMA-FSO communications system for access network solutions. New ABER expressions are derived under gamma-gamma scintillation channels, where all users can surprisingly achieve error-free transmissions when FEC is employed....

Strict optical orthogonal codes for purely asynchronous code-division multiple-access applications

Science.gov (United States)

Zhang, Jian-Guo

1996-12-01

Strict optical orthogonal codes are presented for purely asynchronous optical code-division multiple-access (CDMA) applications. The proposed code can strictly guarantee the peaks of its cross-correlation functions and the sidelobes of any of its autocorrelation functions to have a value of 1 in purely asynchronous data communications. The basic theory of the proposed codes is given. An experiment on optical CDMA systems is also demonstrated to verify the characteristics of the proposed code.

ON THE ISSUE OF VECTOR CONTROL OF THE ASYNCHRONOUS MOTORS

Directory of Open Access Journals (Sweden)

B. I. Firago

2015-01-01

Full Text Available The paper considers the issue of one of the widespread types of vector control realization for the asynchronous motors with a short-circuited rotor. Of all more than 20 vector control types known presently, the following are applied most frequently: direct vector control with velocity pickup (VP, direct vector control without VP, indirect vector control with VP and indirect vector control without VP. Despite the fact that the asynchronous-motor indirect vector control without VP is the easiest and most spread, the absence of VP does not allow controlling the motor electromagnetic torque at zero velocity. This is the reason why for electric motor drives of such requirements they utilize the vector control with a velocity transducer. The systems of widest dissemination became the direct and indirect vector control systems with X-axis alignment of the synchronously rotating x–y-coordinate frame along the rotor flux-linkage vector inasmuch as this provides the simplest correlations for controlling variables. Although these two types of vector control are well presented in literature, a number of issues concerning their realization and practical application require further elaboration. These include: the block schemes adequate representation as consisted with the modern realization of vector control and clarification of the analytical expressions for evaluating the regulator parameters.The authors present a technique for evaluating the dynamics of an asynchronous electric motor drive with direct vector control and x-axis alignment along the vector of rotor flux linkage. The article offers a generalized structure of this vector control type with detailed description of its principal blocks: controlling system, frequency converter, and the asynchronous motor.The paper presents a direct vector control simulating model developed in the MatLab environment on the grounds of this structure. The authors illustrate the described technique with the results

Data Collection for Mobile Group Consumption: An Asynchronous Distributed Approach

Directory of Open Access Journals (Sweden)

Weiping Zhu

2016-04-01

Full Text Available Mobile group consumption refers to consumption by a group of people, such as a couple, a family, colleagues and friends, based on mobile communications. It differs from consumption only involving individuals, because of the complex relations among group members. Existing data collection systems for mobile group consumption are centralized, which has the disadvantages of being a performance bottleneck, having single-point failure and increasing business and security risks. Moreover, these data collection systems are based on a synchronized clock, which is often unrealistic because of hardware constraints, privacy concerns or synchronization cost. In this paper, we propose the first asynchronous distributed approach to collecting data generated by mobile group consumption. We formally built a system model thereof based on asynchronous distributed communication. We then designed a simulation system for the model for which we propose a three-layer solution framework. After that, we describe how to detect the causality relation of two/three gathering events that happened in the system based on the collected data. Various definitions of causality relations based on asynchronous distributed communication are supported. Extensive simulation results show that the proposed approach is effective for data collection relating to mobile group consumption.

Data Collection for Mobile Group Consumption: An Asynchronous Distributed Approach.

Science.gov (United States)

Zhu, Weiping; Chen, Weiran; Hu, Zhejie; Li, Zuoyou; Liang, Yue; Chen, Jiaojiao

2016-04-06

Mobile group consumption refers to consumption by a group of people, such as a couple, a family, colleagues and friends, based on mobile communications. It differs from consumption only involving individuals, because of the complex relations among group members. Existing data collection systems for mobile group consumption are centralized, which has the disadvantages of being a performance bottleneck, having single-point failure and increasing business and security risks. Moreover, these data collection systems are based on a synchronized clock, which is often unrealistic because of hardware constraints, privacy concerns or synchronization cost. In this paper, we propose the first asynchronous distributed approach to collecting data generated by mobile group consumption. We formally built a system model thereof based on asynchronous distributed communication. We then designed a simulation system for the model for which we propose a three-layer solution framework. After that, we describe how to detect the causality relation of two/three gathering events that happened in the system based on the collected data. Various definitions of causality relations based on asynchronous distributed communication are supported. Extensive simulation results show that the proposed approach is effective for data collection relating to mobile group consumption.

Laser dynamics of asynchronous rational harmonic mode-locked fiber soliton lasers

International Nuclear Information System (INIS)

Jyu, Siao-Shan; Jiang, Guo-Hao; Lai, Yinchieh

2013-01-01

Laser dynamics of asynchronous rational harmonic mode-locked (ARHM) fiber soliton lasers are investigated in detail. In particular, based on the unique laser dynamics of asynchronous mode-locking, we have developed a new method for determining the effective active modulation strength in situ for ARHM lasers. By measuring the magnitudes of the slowly oscillating pulse timing position and central frequency, the effective phase modulation strength at the multiplication frequency of rational harmonic mode-locking can be accurately inferred. The method can be a very useful tool for developing ARHM fiber lasers. (paper)

A low-power asynchronous data-path for a FIR filter bank

DEFF Research Database (Denmark)

Nielsen, Lars Skovby; Sparsø, Jens

1996-01-01

This paper describes a number of design issues relating to the implementation of low-power asynchronous signal processing circuits. Specifically, the paper addresses the design of a dedicated processor structure that implements an audio FIR filter bank which is part of an industrial application....... The algorithm requires a fixed number of steps and the moderate speed requirement allows a sequential implementation. The latter, in combination with a huge predominance of numerically small data values in the input data stream, is the key to a low-power asynchronous implementation. Power is minimized in two...

Adaptive hatching hypotheses do not explain asynchronous ...

African Journals Online (AJOL)

At the core of the suite of adaptive hatching hypotheses advanced to explain asynchronous hatching in birds is the assumption that if food is not limited then all the hatchlings will develop normally to adulthood. In this study Brown-headed Parrot Poicephalus cryptoxanthus chicks were hand fed and weighed on a daily basis.

A Scalable GVT Estimation Algorithm for PDES: Using Lower Bound of Event-Bulk-Time

Directory of Open Access Journals (Sweden)

Yong Peng

2015-01-01

Full Text Available Global Virtual Time computation of Parallel Discrete Event Simulation is crucial for conducting fossil collection and detecting the termination of simulation. The triggering condition of GVT computation in typical approaches is generally based on the wall-clock time or logical time intervals. However, the GVT value depends on the timestamps of events rather than the wall-clock time or logical time intervals. Therefore, it is difficult for the existing approaches to select appropriate time intervals to compute the GVT value. In this study, we propose a scalable GVT estimation algorithm based on Lower Bound of Event-Bulk-Time, which triggers the computation of the GVT value according to the number of processed events. In order to calculate the number of transient messages, our algorithm employs Event-Bulk to record the messages sent and received by Logical Processes. To eliminate the performance bottleneck, we adopt an overlapping computation approach to distribute the workload of GVT computation to all worker-threads. We compare our algorithm with the fast asynchronous GVT algorithm using PHOLD benchmark on the shared memory machine. Experimental results indicate that our algorithm has a light overhead and shows higher speedup and accuracy of GVT computation than the fast asynchronous GVT algorithm.

Efficiency of three-phase asynchronous motors. Energy loss reduction by means of overdimensioning; Efficientie van driefasen asynchrone motoren. SinuMEC beperkt energieverlies door overdimensionering

Energy Technology Data Exchange (ETDEWEB)

Peeters, J.; Van Dorst, C. [Hyteps, Gemert (Netherlands)

2008-10-15

The three phase asynchronous motor has been applied in various installations since time immemorial. Although the motor is more efficient at full mechanical load, this is not always applied efficiently. Can the efficiency of low load motors be improved or is this a utopia? The Sinusoidal Motor Controller (SinuMEC) improves efficiency, saves energy and lengthens the life span. [mk]. [Dutch] De driefasen asynchrone motor wordt sinds mensenheugenis in uiteenlopende installaties toegepast. Hoewel de motor met een volle mechanische belasting efficient is, wordt deze niet altijd efficient toegepast. Kan de efficiency van laag belaste motoren worden verbeterd of is dit een utopie? De Sinusoidal Motor efficiency controller (SinuMEC) verbetert de efficiency, bespaart energie en verlengt de levensduur.

Asynchronous L1-gain control of uncertain switched positive linear systems with dwell time.

Science.gov (United States)

Li, Yang; Zhang, Hongbin

2018-04-01

In this paper, dwell time (DT) stability, L 1 -gain performance analysis and asynchronous L 1 -gain controller design problems of uncertain switched positive linear systems (SPLSs) are investigated. Via a time-scheduled multiple linear co-positive Lyapunov function (TSMLCLF) approach, convex sufficient conditions of DT stability and L 1 -gain performance of SPLSs with interval and polytopic uncertainties are presented. Furthermore, by utilizing the feature that the TSMLCLF keeps decreasing even if the controller is running asynchronously with the system, the asynchronous L 1 -gain controller design problem of SPLSs with interval and polytopic uncertainties is investigated. Convex sufficient conditions of the existence of time-varying asynchronous state-feedback controller which can ensure the closed-loop system's positivity, stability and L 1 -gain performance are established, and the controller gain matrices can be calculated instantaneously online. The obtained L 1 -gain in the paper is standard. All the results are presented in terms of linear programming. A practical example is provided to show the effectiveness of the results. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

Analysis and application of two recursive parametric estimation algorithms for an asynchronous machine

International Nuclear Information System (INIS)

Damek, Nawel; Kamoun, Samira

2011-01-01

In this communication, two recursive parametric estimation algorithms are analyzed and applied to an squirrelcage asynchronous machine located at the research ''Unit of Automatic Control'' (UCA) at ENIS. The first algorithm which, use the transfer matrix mathematical model, is based on the gradient principle. The second algorithm, which use the state-space mathematical model, is based on the minimization of the estimation error. These algorithms are applied as a key technique to estimate asynchronous machine with unknown, but constant or timevarying parameters. Stator voltage and current are used as measured data. The proposed recursive parametric estimation algorithms are validated on the experimental data of an asynchronous machine under normal operating condition as full load. The results show that these algorithms can estimate effectively the machine parameters with reliability.

Unexpected strong attraction in the presence of continuum bound state

International Nuclear Information System (INIS)

Delfino, A.; Frederico, T.

1992-06-01

The result of few-particle ground-state calculation employing a two-particle non-local potential supporting a continuum bound state in addition to a negative-energy bound state has occasionally revealed unexpected large attraction in producing a very strongly bound ground state. In the presence of the continuum bound state the difference of phase shift between zero and infinite energies has an extra jump of φ as in the presence of an additional bound state. The wave function of the continuum bound state is identical with that of a strongly bound negative-energy state, which leads us to postulate a pseudo bound state in the two-particle system in order to explain the unexpected attraction. The role of the Pauli forbidden states is expected to be similar to these pseudo states. (author)

An Efficient Algorithm for Computing Attractors of Synchronous And Asynchronous Boolean Networks

Science.gov (United States)

Zheng, Desheng; Yang, Guowu; Li, Xiaoyu; Wang, Zhicai; Liu, Feng; He, Lei

2013-01-01

Biological networks, such as genetic regulatory networks, often contain positive and negative feedback loops that settle down to dynamically stable patterns. Identifying these patterns, the so-called attractors, can provide important insights for biologists to understand the molecular mechanisms underlying many coordinated cellular processes such as cellular division, differentiation, and homeostasis. Both synchronous and asynchronous Boolean networks have been used to simulate genetic regulatory networks and identify their attractors. The common methods of computing attractors are that start with a randomly selected initial state and finish with exhaustive search of the state space of a network. However, the time complexity of these methods grows exponentially with respect to the number and length of attractors. Here, we build two algorithms to achieve the computation of attractors in synchronous and asynchronous Boolean networks. For the synchronous scenario, combing with iterative methods and reduced order binary decision diagrams (ROBDD), we propose an improved algorithm to compute attractors. For another algorithm, the attractors of synchronous Boolean networks are utilized in asynchronous Boolean translation functions to derive attractors of asynchronous scenario. The proposed algorithms are implemented in a procedure called geneFAtt. Compared to existing tools such as genYsis, geneFAtt is significantly faster in computing attractors for empirical experimental systems. Availability The software package is available at https://sites.google.com/site/desheng619/download. PMID:23585840

Asynchronous Channel-Hopping Scheme under Jamming Attacks

Directory of Open Access Journals (Sweden)

Yongchul Kim

2018-01-01

Full Text Available Cognitive radio networks (CRNs are considered an attractive technology to mitigate inefficiency in the usage of licensed spectrum. CRNs allow the secondary users (SUs to access the unused licensed spectrum and use a blind rendezvous process to establish communication links between SUs. In particular, quorum-based channel-hopping (CH schemes have been studied recently to provide guaranteed blind rendezvous in decentralized CRNs without using global time synchronization. However, these schemes remain vulnerable to jamming attacks. In this paper, we first analyze the limitations of quorum-based rendezvous schemes called asynchronous channel hopping (ACH. Then, we introduce a novel sequence sensing jamming attack (SSJA model in which a sophisticated jammer can dramatically reduce the rendezvous success rates of ACH schemes. In addition, we propose a fast and robust asynchronous rendezvous scheme (FRARS that can significantly enhance robustness under jamming attacks. Our numerical results demonstrate that the performance of the proposed scheme vastly outperforms the ACH scheme when there are security concerns about a sequence sensing jammer.

Positive semidefinite integrated covariance estimation, factorizations and asynchronicity

DEFF Research Database (Denmark)

Boudt, Kris; Laurent, Sébastien; Lunde, Asger

2017-01-01

An estimator of the ex-post covariation of log-prices under asynchronicity and microstructure noise is proposed. It uses the Cholesky factorization of the covariance matrix in order to exploit the heterogeneity in trading intensities to estimate the different parameters sequentially with as many...

Positive Semidefinite Integrated Covariance Estimation, Factorizations and Asynchronicity

DEFF Research Database (Denmark)

Boudt, Kris; Laurent, Sébastien; Lunde, Asger

An estimator of the ex-post covariation of log-prices under asynchronicity and microstructure noise is proposed. It uses the Cholesky factorization on the correlation matrix in order to exploit the heterogeneity in trading intensity to estimate the different parameters sequentially with as many...

Verification and Planning for Stochastic Processes with Asynchronous Events

National Research Council Canada - National Science Library

Younes, Hakan L

2005-01-01

.... The most common assumption is that of history-independence: the Markov assumption. In this thesis, the author considers the problems of verification and planning for stochastic processes with asynchronous events, without relying on the Markov assumption...

Evaluation of asynchronous E-learning in the geography curriculum: enriching learning quality in Saudi high schools

OpenAIRE

Al Dobaikhi, Hend; Woollard, John

2011-01-01

The impacts of emerging ICT into educational curricula Asynchronous discussion forumDiscussion groups via e-learning environmentPosting questions and commentsSelf-efficacy in asynchronous e-learning Web community participationCollaborative learning can be fosteredPositive impacts on objectives of educational curriculum

Adding the Human Touch to Asynchronous Online Learning

Science.gov (United States)

Glenn, Cynthia Wheatley

2018-01-01

For learners to actively accept responsibility in a virtual classroom platform, it is necessary to provide special motivation extending across the traditional classroom setting into asynchronous online learning. This article explores specific ways to do this that bridge the gap between ground and online students' learning experiences, and how…

Designing a Web-Based Asynchronous Innovation/Entrepreneurism Course

Science.gov (United States)

Ghandforoush, Parviz

2017-01-01

Teaching an online fully asynchronous information technology course that requires students to ideate, build an e-commerce website, and develop an effective business plan involves a well-developed and highly engaging course design. This paper describes the design, development, and implementation of such a course and presents information on…

Asynchronous decision making in a memorized paddle pressing task.

Science.gov (United States)

Dankert, James R; Olson, Byron; Si, Jennie

2008-12-01

This paper presents a method for asynchronous decision making using recorded neural data in a binary decision task. This is a demonstration of a technique for developing motor cortical neural prosthetics that do not rely on external cued timing information. The system presented in this paper uses support vector machines and leaky integrate-and-fire elements to predict directional paddle presses. In addition to the traditional metrics of accuracy, asynchronous systems must also optimize the time needed to make a decision. The system presented is able to predict paddle presses with a median accuracy of 88% and all decisions are made before the time of the actual paddle press. An alternative bit rate measure of performance is defined to show that the system proposed here is able to perform the task with the same efficiency as the rats.

Features of the Asynchronous Correlation between the China Coal Price Index and Coal Mining Accidental Deaths

Science.gov (United States)

Huang, Yuecheng; Cheng, Wuyi; Luo, Sida; Luo, Yun; Ma, Chengchen; He, Tailin

2016-01-01

The features of the asynchronous correlation between accident indices and the factors that influence accidents can provide an effective reference for warnings of coal mining accidents. However, what are the features of this correlation? To answer this question, data from the China coal price index and the number of deaths from coal mining accidents were selected as the sample data. The fluctuation modes of the asynchronous correlation between the two data sets were defined according to the asynchronous correlation coefficients, symbolization, and sliding windows. We then built several directed and weighted network models, within which the fluctuation modes and the transformations between modes were represented by nodes and edges. Then, the features of the asynchronous correlation between these two variables could be studied from a perspective of network topology. We found that the correlation between the price index and the accidental deaths was asynchronous and fluctuating. Certain aspects, such as the key fluctuation modes, the subgroups characteristics, the transmission medium, the periodicity and transmission path length in the network, were analyzed by using complex network theory, analytical methods and spectral analysis method. These results provide a scientific reference for generating warnings for coal mining accidents based on economic indices. PMID:27902748

Data Collection for Mobile Group Consumption: An Asynchronous Distributed Approach †

Science.gov (United States)

Zhu, Weiping; Chen, Weiran; Hu, Zhejie; Li, Zuoyou; Liang, Yue; Chen, Jiaojiao

2016-01-01

Mobile group consumption refers to consumption by a group of people, such as a couple, a family, colleagues and friends, based on mobile communications. It differs from consumption only involving individuals, because of the complex relations among group members. Existing data collection systems for mobile group consumption are centralized, which has the disadvantages of being a performance bottleneck, having single-point failure and increasing business and security risks. Moreover, these data collection systems are based on a synchronized clock, which is often unrealistic because of hardware constraints, privacy concerns or synchronization cost. In this paper, we propose the first asynchronous distributed approach to collecting data generated by mobile group consumption. We formally built a system model thereof based on asynchronous distributed communication. We then designed a simulation system for the model for which we propose a three-layer solution framework. After that, we describe how to detect the causality relation of two/three gathering events that happened in the system based on the collected data. Various definitions of causality relations based on asynchronous distributed communication are supported. Extensive simulation results show that the proposed approach is effective for data collection relating to mobile group consumption. PMID:27058544

The study of transient processes in the asynchronous starting of the synchronous motor

OpenAIRE

Alexandru Bârlea; Olivian Chiver

2012-01-01

Starting synchronous motors can be achieved by several ethods: starting with an auxiliary motor launch, starting in asynchronous regim, by feeding from a variable frequency source, auto-synchronization with the network.. In our case we study the transient processes in a asynchronous regim . In this case the synchronous motor is started like a squirrel cage induction motor . To start, the synchronous motor is equipped with a starting winding cage placed in the pole pieces of polar inducers; la...

Asynchronous hatching provides females with a means for increasing male care but incurs a cost by reducing offspring fitness.

Science.gov (United States)

Ford, L E; Smiseth, P T

2016-02-01

In species with biparental care, sexual conflict occurs because the benefit of care depends on the total amount of care provided by the two parents while the cost of care depends on each parent's own contribution. Asynchronous hatching may play a role in mediating the resolution of this conflict over parental care. The sexual conflict hypothesis for the evolution of asynchronous hatching suggests that females adjust hatching patterns in order to increase male parental effort relative to female effort. We tested this hypothesis in the burying beetle Nicrophorus vespilloides by setting up experimental broods with three different hatching patterns: synchronous, asynchronous and highly asynchronous broods. As predicted, we found that males provided care for longer in asynchronous broods whereas the opposite was true of females. However, we did not find any benefit to females of reducing their duration of care in terms of increased lifespan or reduced mass loss during breeding. We found substantial negative effects of hatching asynchrony on offspring fitness as larval mass was lower and fewer larvae survived to dispersal in highly asynchronous broods compared to synchronous or asynchronous broods. Our results suggest that, even though females can increase male parental effort by hatching their broods more asynchronously, females pay a substantial cost from doing so in terms of reducing offspring growth and survival. Thus, females should be under selection to produce a hatching pattern that provides the best possible trade-off between the benefits of increased male parental effort and the costs due to reduced offspring fitness. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

Dual stator winding variable speed asynchronous generator: optimal design and experiments

International Nuclear Information System (INIS)

Tutelea, L N; Deaconu, S I; Popa, G N

2015-01-01

In the present paper is carried out a theoretical and experimental study of dual stator winding squirrel cage asynchronous generator (DSWA) behavior in the presence of saturation regime (non-sinusoidal) due to the variable speed operation. The main aims are the determination of the relations of calculating the equivalent parameters of the machine windings to optimal design using a Matlab code. Issue is limited to three phase range of double stator winding cage-induction generator of small sized powers, the most currently used in the small adjustable speed wind or hydro power plants. The tests were carried out using three-phase asynchronous generator having rated power of 6 [kVA]. (paper)

Asynchronous Assessment in a Large Lecture Marketing Course

Science.gov (United States)

Downey, W. Scott; Schetzsle, Stacey

2012-01-01

Asynchronous assessment, which includes quizzes or exams online or outside class, offers marketing educators an opportunity to make more efficient use of class time and to enhance students' learning experiences by giving them more flexibility and choice in their assessment environment. In this paper, we examine the performance difference between…

Spatiotemporal Features for Asynchronous Event-based Data

Directory of Open Access Journals (Sweden)

Xavier eLagorce

2015-02-01

Full Text Available Bio-inspired asynchronous event-based vision sensors are currently introducing a paradigm shift in visual information processing. These new sensors rely on a stimulus-driven principle of light acquisition similar to biological retinas. They are event-driven and fully asynchronous, thereby reducing redundancy and encoding exact times of input signal changes, leading to a very precise temporal resolution. Approaches for higher-level computer vision often rely on the realiable detection of features in visual frames, but similar definitions of features for the novel dynamic and event-based visual input representation of silicon retinas have so far been lacking. This article addresses the problem of learning and recognizing features for event-based vision sensors, which capture properties of truly spatiotemporal volumes of sparse visual event information. A novel computational architecture for learning and encoding spatiotemporal features is introduced based on a set of predictive recurrent reservoir networks, competing via winner-take-all selection. Features are learned in an unsupervised manner from real-world input recorded with event-based vision sensors. It is shown that the networks in the architecture learn distinct and task-specific dynamic visual features, and can predict their trajectories over time.

Asynchronous schemes for CFD at extreme scales

Science.gov (United States)

Konduri, Aditya; Donzis, Diego

2013-11-01

Recent advances in computing hardware and software have made simulations an indispensable research tool in understanding fluid flow phenomena in complex conditions at great detail. Due to the nonlinear nature of the governing NS equations, simulations of high Re turbulent flows are computationally very expensive and demand for extreme levels of parallelism. Current large simulations are being done on hundreds of thousands of processing elements (PEs). Benchmarks from these simulations show that communication between PEs take a substantial amount of time, overwhelming the compute time, resulting in substantial waste in compute cycles as PEs remain idle. We investigate a novel approach based on widely used finite-difference schemes in which computations are carried out asynchronously, i.e. synchronization of data among PEs is not enforced and computations proceed regardless of the status of messages. This drastically reduces PE idle time and results in much larger computation rates. We show that while these schemes remain stable, their accuracy is significantly affected. We present new schemes that maintain accuracy under asynchronous conditions and provide a viable path towards exascale computing. Performance of these schemes will be shown for simple models like Burgers' equation.

Asynchronous replication and autosome-pair non-equivalence in human embryonic stem cells.

Directory of Open Access Journals (Sweden)

Devkanya Dutta

Full Text Available A number of mammalian genes exhibit the unusual properties of random monoallelic expression and random asynchronous replication. Such exceptional genes include genes subject to X inactivation and autosomal genes including odorant receptors, immunoglobulins, interleukins, pheromone receptors, and p120 catenin. In differentiated cells, random asynchronous replication of interspersed autosomal genes is coordinated at the whole chromosome level, indicative of chromosome-pair non-equivalence. Here we have investigated the replication pattern of the random asynchronously replicating genes in undifferentiated human embryonic stem cells, using fluorescence in situ hybridization based assay. We show that allele-specific replication of X-linked genes and random monoallelic autosomal genes occur in human embryonic stem cells. The direction of replication is coordinated at the whole chromosome level and can cross the centromere, indicating the existence of autosome-pair non-equivalence in human embryonic stem cells. These results suggest that epigenetic mechanism(s that randomly distinguish between two parental alleles are emerging in the cells of the inner cell mass, the source of human embryonic stem cells.

Content Analysis Coding Schemes for Online Asynchronous Discussion

Science.gov (United States)

Weltzer-Ward, Lisa

2011-01-01

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

An Asynchronous Low Power and High Performance VLSI Architecture for Viterbi Decoder Implemented with Quasi Delay Insensitive Templates

Directory of Open Access Journals (Sweden)

T. Kalavathi Devi

2015-01-01

Full Text Available Convolutional codes are comprehensively used as Forward Error Correction (FEC codes in digital communication systems. For decoding of convolutional codes at the receiver end, Viterbi decoder is often used to have high priority. This decoder meets the demand of high speed and low power. At present, the design of a competent system in Very Large Scale Integration (VLSI technology requires these VLSI parameters to be finely defined. The proposed asynchronous method focuses on reducing the power consumption of Viterbi decoder for various constraint lengths using asynchronous modules. The asynchronous designs are based on commonly used Quasi Delay Insensitive (QDI templates, namely, Precharge Half Buffer (PCHB and Weak Conditioned Half Buffer (WCHB. The functionality of the proposed asynchronous design is simulated and verified using Tanner Spice (TSPICE in 0.25 µm, 65 nm, and 180 nm technologies of Taiwan Semiconductor Manufacture Company (TSMC. The simulation result illustrates that the asynchronous design techniques have 25.21% of power reduction compared to synchronous design and work at a speed of 475 MHz.

Thermalization Time Bounds for Pauli Stabilizer Hamiltonians

Science.gov (United States)

Temme, Kristan

2017-03-01

We prove a general lower bound to the spectral gap of the Davies generator for Hamiltonians that can be written as the sum of commuting Pauli operators. These Hamiltonians, defined on the Hilbert space of N-qubits, serve as one of the most frequently considered candidates for a self-correcting quantum memory. A spectral gap bound on the Davies generator establishes an upper limit on the life time of such a quantum memory and can be used to estimate the time until the system relaxes to thermal equilibrium when brought into contact with a thermal heat bath. The bound can be shown to behave as {λ ≥ O(N^{-1} exp(-2β overline{ɛ}))}, where {overline{ɛ}} is a generalization of the well known energy barrier for logical operators. Particularly in the low temperature regime we expect this bound to provide the correct asymptotic scaling of the gap with the system size up to a factor of N -1. Furthermore, we discuss conditions and provide scenarios where this factor can be removed and a constant lower bound can be proven.

Miscellany of Students' Satisfaction in an Asynchronous Learning Environment

Science.gov (United States)

Larbi-Siaw, Otu; Owusu-Agyeman, Yaw

2017-01-01

This study investigates the determinants of students' satisfaction in an asynchronous learning environment using seven key considerations: the e-learning environment, student-content interaction, student and student interaction, student-teacher interaction, group cohesion and timely participation, knowledge of Internet usage, and satisfaction. The…

A Novel Approach to Asynchronous MVP Data Interpretation Based on Elliptical-Vectors

Science.gov (United States)

Kruglyakov, M.; Trofimov, I.; Korotaev, S.; Shneyer, V.; Popova, I.; Orekhova, D.; Scshors, Y.; Zhdanov, M. S.

2014-12-01

We suggest a novel approach to asynchronous magnetic-variation profiling (MVP) data interpretation. Standard method in MVP is based on the interpretation of the coefficients of linear relation between vertical and horizontal components of the measured magnetic field.From mathematical point of view this pair of linear coefficients is not a vector which leads to significant difficulties in asynchronous data interpretation. Our approach allows us to actually treat such a pair of complex numbers as a special vector called an ellipse-vector (EV). By choosing the particular definitions of complex length and direction, the basic relation of MVP can be considered as the dot product. This considerably simplifies the interpretation of asynchronous data. The EV is described by four real numbers: the values of major and minor semiaxes, the angular direction of the major semiaxis and the phase. The notation choice is motivated by historical reasons. It is important that different EV's components have different sensitivity with respect to the field sources and the local heterogeneities. Namely, the value of major semiaxis and the angular direction are mostly determined by the field source and the normal cross-section. On the other hand, the value of minor semiaxis and the phase are responsive to local heterogeneities. Since the EV is the general form of complex vector, the traditional Schmucker vectors can be explicitly expressed through its components.The proposed approach was successfully applied to interpretation the results of asynchronous measurements that had been obtained in the Arctic Ocean at the drift stations "North Pole" in 1962-1976.

The Interplay of Content and Community in Synchronous and Asynchronous Communication: Virtual Communication in a Graduate Seminar

Directory of Open Access Journals (Sweden)

Richard A. Schwier

2002-06-01

Full Text Available A group of graduate students and an instructor at the University of Saskatchewan experimented with the use of synchronous communication (chat and asynchronous communication (bulletin board in a theory course in Educational Communications and Technology for an eight-month period. Synchronous communication contributed dramatically to the continuity and convenience of the class, and promoted a strong sense of community. At the same time, it was viewed as less effective than asynchronous communication for dealing with content and issues deeply, and it introduced a number of pedagogical and intellectual limitations. We concluded that synchronous and asynchronous strategies were suitable for different types of learning, and what we experienced was a balancing act between content and community in our group. A combination of synchronous and asynchronous experiences seems to be necessary to promote the kind of engagement and depth required in a graduate seminar.

Performance analysis of 2D asynchronous hard-limiting optical code-division multiple access system through atmospheric scattering channel

Science.gov (United States)

Zhao, Yaqin; Zhong, Xin; Wu, Di; Zhang, Ye; Ren, Guanghui; Wu, Zhilu

2013-09-01

Optical code-division multiple access (OCDMA) systems usually allocate orthogonal or quasi-orthogonal codes to the active users. When transmitting through atmospheric scattering channel, the coding pulses are broadened and the orthogonality of the codes is worsened. In truly asynchronous case, namely both the chips and the bits are asynchronous among each active user, the pulse broadening affects the system performance a lot. In this paper, we evaluate the performance of a 2D asynchronous hard-limiting wireless OCDMA system through atmospheric scattering channel. The probability density function of multiple access interference in truly asynchronous case is given. The bit error rate decreases as the ratio of the chip period to the root mean square delay spread increases and the channel limits the bit rate to different levels when the chip period varies.

Efficiency gains, bounds, and risk in finance

NARCIS (Netherlands)

Sarisoy, Cisil

2015-01-01

This thesis consists of three chapters. The first chapter analyzes efficiency gains in the estimation of expected returns based on asset pricing models and examines the economic implications of such gains in portfolio allocation exercises. The second chapter provides nonparametric efficiency bounds

Asynchronous Multi-Party Computation with Quadratic Communication

DEFF Research Database (Denmark)

Hirt, Martin; Nielsen, Jesper Buus; Przydatek, Bartosz

2008-01-01

We present an efficient protocol for secure multi-party computation in the asynchronous model with optimal resilience. For n parties, up to t < n/3 of them being corrupted, and security parameter κ, a circuit with c gates can be securely computed with communication complexity O(cn^2k) bits, which...... circuit randomization due to Beaver (Crypto’91), and an abstraction of certificates, which can be of independent interest....

A modular control architecture for real-time synchronous and asynchronous systems

International Nuclear Information System (INIS)

Butler, P.L.; Jones, J.P.

1993-01-01

This paper describes a control architecture for real-time control of complex robotic systems. The Modular Integrated Control Architecture (MICA), which is actually two complementary control systems, recognizes and exploits the differences between asynchronous and synchronous control. The asynchronous control system simulates shared memory on a heterogeneous network. For control information, a portable event-scheme is used. This scheme provides consistent interprocess coordination among multiple tasks on a number of distributed systems. The machines in the network can vary with respect to their native operating systems and the intemal representation of numbers they use. The synchronous control system is needed for tight real-time control of complex electromechanical systems such as robot manipulators, and the system uses multiple processors at a specified rate. Both the synchronous and asynchronous portions of MICA have been developed to be extremely modular. MICA presents a simple programming model to code developers and also considers the needs of system integrators and maintainers. MICA has been used successfully in a complex robotics project involving a mobile 7-degree-of-freedom manipulator in a heterogeneous network with a body of software totaling over 100,000 lines of code. MICA has also been used in another robotics system, controlling a commercial long-reach manipulator

Full-load converter connected asynchronous generators for MW class wind turbines

Energy Technology Data Exchange (ETDEWEB)

Akhmatov, Vladislav

2005-06-15

Wind turbines equipped with full-load converter-connected asynchronous generators are a known concept. These have rating up to hundreds of kW and are a feasible concept for MW class wind turbines and may have advantages when compared to conventional wind turbines with directly connected generators. The concept requires the use of full-scale frequency converters, but the mechanical gearbox is smaller than in conventional wind turbines of the same rating. Application of smaller gearbox may reduce the no-load losses in the wind turbines, which is why such wind turbines with converter connected generators may start operation at a smaller wind speed. Wind turbines equipped with such converted connected asynchronous generators are pitch-controlled and variable-speed. This allows better performance and control. The converter control may be applied to support the grid voltage at short-circuit faults and to improve the fault-ride-through capability of the wind turbines, which makes the concepts relevant for large wind farms. The Danish transmission system operator Energinet-DK has implemented the general model of wind turbines equipped with converter connected asynchronous generators with the simulation tool Powerfactory (DlgSilent). The article presents Energinet-DK's experience of modeling this feasible wind turbine concept. (Author)

Turing Incompleteness of Asynchronous P Systems with Active Membranes

OpenAIRE

Leporati, Alberto; Manzoni, Luca; Porreca, Antonio E.

2013-01-01

We prove that asynchronous P systems with active membranes without divi- sion rules can be simulated by place/transition Petri nets, and hence are computationally weaker than Turing machines. This result holds even if the synchronisation mechanisms provided by electrical charges and membrane dissolution are exploited.

An improved modelling of asynchronous machine with skin-effect ...

African Journals Online (AJOL)

The conventional method of analysis of Asynchronous machine fails to give accurate results especially when the machine is operated under high rotor frequency. At high rotor frequency, skin-effect dominates causing the rotor impedance to be frequency dependant. This paper therefore presents an improved method of ...

Comparison between Synchronous and Asynchronous Instructional Delivery Method of Training Programme on In-Service Physical Educators' Knowledge

Science.gov (United States)

Emmanouilidou, Kyriaki; Derri, Vassiliki; Antoniou, Panagiotis; Kyrgiridis, Pavlos

2012-01-01

The purpose of the study was to compare the influences of a training programme's instructional delivery method (synchronous and asynchronous) on Greek in-service physical educators' cognitive understanding on student assessment. Forty nine participants were randomly divided into synchronous, asynchronous, and control group. The experimental groups…

Parallel, Asynchronous Executive (PAX): System concepts, facilities, and architecture

Science.gov (United States)

Jones, W. H.

1983-01-01

The Parallel, Asynchronous Executive (PAX) is a software operating system simulation that allows many computers to work on a single problem at the same time. PAX is currently implemented on a UNIVAC 1100/42 computer system. Independent UNIVAC runstreams are used to simulate independent computers. Data are shared among independent UNIVAC runstreams through shared mass-storage files. PAX has achieved the following: (1) applied several computing processes simultaneously to a single, logically unified problem; (2) resolved most parallel processor conflicts by careful work assignment; (3) resolved by means of worker requests to PAX all conflicts not resolved by work assignment; (4) provided fault isolation and recovery mechanisms to meet the problems of an actual parallel, asynchronous processing machine. Additionally, one real-life problem has been constructed for the PAX environment. This is CASPER, a collection of aerodynamic and structural dynamic problem simulation routines. CASPER is not discussed in this report except to provide examples of parallel-processing techniques.

Area/latency optimized early output asynchronous full adders and relative-timed ripple carry adders.

Science.gov (United States)

Balasubramanian, P; Yamashita, S

2016-01-01

This article presents two area/latency optimized gate level asynchronous full adder designs which correspond to early output logic. The proposed full adders are constructed using the delay-insensitive dual-rail code and adhere to the four-phase return-to-zero handshaking. For an asynchronous ripple carry adder (RCA) constructed using the proposed early output full adders, the relative-timing assumption becomes necessary and the inherent advantages of the relative-timed RCA are: (1) computation with valid inputs, i.e., forward latency is data-dependent, and (2) computation with spacer inputs involves a bare minimum constant reverse latency of just one full adder delay, thus resulting in the optimal cycle time. With respect to different 32-bit RCA implementations, and in comparison with the optimized strong-indication, weak-indication, and early output full adder designs, one of the proposed early output full adders achieves respective reductions in latency by 67.8, 12.3 and 6.1 %, while the other proposed early output full adder achieves corresponding reductions in area by 32.6, 24.6 and 6.9 %, with practically no power penalty. Further, the proposed early output full adders based asynchronous RCAs enable minimum reductions in cycle time by 83.4, 15, and 8.8 % when considering carry-propagation over the entire RCA width of 32-bits, and maximum reductions in cycle time by 97.5, 27.4, and 22.4 % for the consideration of a typical carry chain length of 4 full adder stages, when compared to the least of the cycle time estimates of various strong-indication, weak-indication, and early output asynchronous RCAs of similar size. All the asynchronous full adders and RCAs were realized using standard cells in a semi-custom design fashion based on a 32/28 nm CMOS process technology.

Lying for the Greater Good: Bounded Rationality in a Team

Directory of Open Access Journals (Sweden)

Oktay Sürücü

2014-10-01

Full Text Available This paper is concerned with the interaction between fully and boundedly rational agents in situations where their interests are perfectly aligned. The cognitive limitations of the boundedly rational agent do not allow him to fully understand the market conditions and lead him to take non-optimal decisions in some situations. Using categorization to model bounded rationality, we show that the fully rational agent can nudge, i.e., he can manipulate the information he sends and decrease the expected loss caused by the boundedly rational agent. Assuming different types for the boundedly rational agent, who differ only in the categories used, we show that the fully rational agent may learn the type of the boundedly rational agent along their interaction. Using this additional information, the outcome can be improved and the amount of manipulated information can be decreased. Furthermore, as the length of the interaction increases the probability that the fully rational agent learns the type of the boundedly rational agent grows

A tighter bound for the self-stabilization time in Hermanʼs algorithm

DEFF Research Database (Denmark)

Feng, Yuan; Zhang, Lijun

2013-01-01

We study the expected self-stabilization time of Hermanʼs algorithm. For N processors the lower bound is 427N2 (0.148N2), and an upper bound of 0.64N2 is presented in Kiefer et al. (2011) [4]. In this paper we give a tighter upper bound 0.521N2. © 2013 Published by Elsevier B.V....

Upper Bounds for Ruin Probability with Stochastic Investment Return

Institute of Scientific and Technical Information of China (English)

ZHANG Lihong

2005-01-01

Risk models with stochastic investment return are widely held in practice, as well as in more challenging research fields. Risk theory is mainly concerned with ruin probability, and a tight bound for ruin probability is the best for practical use. This paper presents a discrete time risk model with stochastic investment return. Conditional expectation properties and martingale inequalities are used to obtain both exponential and non-exponential upper bounds for the ruin probability.

Integration of asynchronous knowledge sources in a novel speech recognition framework

OpenAIRE

Van hamme, Hugo

2008-01-01

Van hamme H., ''Integration of asynchronous knowledge sources in a novel speech recognition framework'', Proceedings ITRW on speech analysis and processing for knowledge discovery, 4 pp., June 2008, Aalborg, Denmark.

Fitness levels with tail bounds for the analysis of randomized search heuristics

DEFF Research Database (Denmark)

Witt, Carsten

2014-01-01

The fitness-level method, also called the method of f-based partitions, is an intuitive and widely used technique for the running time analysis of randomized search heuristics. It was originally defined to prove upper and lower bounds on the expected running time. Recently, upper tail bounds were...

Asynchronous P300-based brain-computer interface to control a virtual environment: initial tests on end users.

Science.gov (United States)

Aloise, Fabio; Schettini, Francesca; Aricò, Pietro; Salinari, Serenella; Guger, Christoph; Rinsma, Johanna; Aiello, Marco; Mattia, Donatella; Cincotti, Febo

2011-10-01

Motor disability and/or ageing can prevent individuals from fully enjoying home facilities, thus worsening their quality of life. Advances in the field of accessible user interfaces for domotic appliances can represent a valuable way to improve the independence of these persons. An asynchronous P300-based Brain-Computer Interface (BCI) system was recently validated with the participation of healthy young volunteers for environmental control. In this study, the asynchronous P300-based BCI for the interaction with a virtual home environment was tested with the participation of potential end-users (clients of a Frisian home care organization) with limited autonomy due to ageing and/or motor disabilities. System testing revealed that the minimum number of stimulation sequences needed to achieve correct classification had a higher intra-subject variability in potential end-users with respect to what was previously observed in young controls. Here we show that the asynchronous modality performed significantly better as compared to the synchronous mode in continuously adapting its speed to the users' state. Furthermore, the asynchronous system modality confirmed its reliability in avoiding misclassifications and false positives, as previously shown in young healthy subjects. The asynchronous modality may contribute to filling the usability gap between BCI systems and traditional input devices, representing an important step towards their use in the activities of daily living.

A feedback-retransmission based asynchronous frequency hopping MAC protocol for military aeronautical ad hoc networks

Directory of Open Access Journals (Sweden)

Jinhui TANG

2018-05-01

Full Text Available Attacking time-sensitive targets has rigid demands for the timeliness and reliability of information transmission, while typical Media Access Control (MAC designed for this application works well only in very light-load scenarios; as a consequence, the performances of system throughput and channel utilization are degraded. For this problem, a feedback-retransmission based asynchronous FRequency hopping Media Access (FRMA control protocol is proposed. Burst communication, asynchronous Frequency Hopping (FH, channel coding, and feedback retransmission are utilized in FRMA. With the mechanism of asynchronous FH, immediate packet transmission and multi-packet reception can be realized, and thus the timeliness is improved. Furthermore, reliability can be achieved via channel coding and feedback retransmission. With theories of queuing theory, Markov model, packets collision model, and discrete Laplace transformation, the formulas of packet success probability, system throughput, average packet end-to-end delay, and delay distribution are obtained. The approximation accuracy of theoretical derivation is verified by experimental results. Within a light-load network, the proposed FRMA has the ability of millisecond delay and 99% reliability as well as outperforms the non-feedback-retransmission based asynchronous frequency hopping media access control protocol. Keywords: Ad hoc networks, Aeronautical communications, Frequency hopping, Media Access Control (MAC, Time-sensitive

AP-IO: asynchronous pipeline I/O for hiding periodic output cost in CFD simulation.

Science.gov (United States)

Xiaoguang, Ren; Xinhai, Xu

2014-01-01

Computational fluid dynamics (CFD) simulation often needs to periodically output intermediate results to files in the form of snapshots for visualization or restart, which seriously impacts the performance. In this paper, we present asynchronous pipeline I/O (AP-IO) optimization scheme for the periodically snapshot output on the basis of asynchronous I/O and CFD application characteristics. In AP-IO, dedicated background I/O processes or threads are in charge of handling the file write in pipeline mode, therefore the write overhead can be hidden with more calculation than classic asynchronous I/O. We design the framework of AP-IO and implement it in OpenFOAM, providing CFD users with a user-friendly interface. Experimental results on the Tianhe-2 supercomputer demonstrate that AP-IO can achieve a good optimization effect for the periodical snapshot output in CFD application, and the effect is especially better for massively parallel CFD simulations, which can reduce the total execution time up to about 40%.

AP-IO: Asynchronous Pipeline I/O for Hiding Periodic Output Cost in CFD Simulation

Directory of Open Access Journals (Sweden)

Ren Xiaoguang

2014-01-01

Full Text Available Computational fluid dynamics (CFD simulation often needs to periodically output intermediate results to files in the form of snapshots for visualization or restart, which seriously impacts the performance. In this paper, we present asynchronous pipeline I/O (AP-IO optimization scheme for the periodically snapshot output on the basis of asynchronous I/O and CFD application characteristics. In AP-IO, dedicated background I/O processes or threads are in charge of handling the file write in pipeline mode, therefore the write overhead can be hidden with more calculation than classic asynchronous I/O. We design the framework of AP-IO and implement it in OpenFOAM, providing CFD users with a user-friendly interface. Experimental results on the Tianhe-2 supercomputer demonstrate that AP-IO can achieve a good optimization effect for the periodical snapshot output in CFD application, and the effect is especially better for massively parallel CFD simulations, which can reduce the total execution time up to about 40%.

Asynchronous data change notification between database server and accelerator controls system

International Nuclear Information System (INIS)

Fu, W.; Morris, J.; Nemesure, S.

2011-01-01

Database data change notification (DCN) is a commonly used feature. Not all database management systems (DBMS) provide an explicit DCN mechanism. Even for those DBMS's which support DCN (such as Oracle and MS SQL server), some server side and/or client side programming may be required to make the DCN system work. This makes the setup of DCN between database server and interested clients tedious and time consuming. In accelerator control systems, there are many well established software client/server architectures (such as CDEV, EPICS, and ADO) that can be used to implement data reflection servers that transfer data asynchronously to any client using the standard SET/GET API. This paper describes a method for using such a data reflection server to set up asynchronous DCN (ADCN) between a DBMS and clients. This method works well for all DBMS systems which provide database trigger functionality. Asynchronous data change notification (ADCN) between database server and clients can be realized by combining the use of a database trigger mechanism, which is supported by major DBMS systems, with server processes that use client/server software architectures that are familiar in the accelerator controls community (such as EPICS, CDEV or ADO). This approach makes the ADCN system easy to set up and integrate into an accelerator controls system. Several ADCN systems have been set up and used in the RHIC-AGS controls system.

Continuous EEG signal analysis for asynchronous BCI application.

Science.gov (United States)

Hsu, Wei-Yen

2011-08-01

In this study, we propose a two-stage recognition system for continuous analysis of electroencephalogram (EEG) signals. An independent component analysis (ICA) and correlation coefficient are used to automatically eliminate the electrooculography (EOG) artifacts. Based on the continuous wavelet transform (CWT) and Student's two-sample t-statistics, active segment selection then detects the location of active segment in the time-frequency domain. Next, multiresolution fractal feature vectors (MFFVs) are extracted with the proposed modified fractal dimension from wavelet data. Finally, the support vector machine (SVM) is adopted for the robust classification of MFFVs. The EEG signals are continuously analyzed in 1-s segments, and every 0.5 second moves forward to simulate asynchronous BCI works in the two-stage recognition architecture. The segment is first recognized as lifted or not in the first stage, and then is classified as left or right finger lifting at stage two if the segment is recognized as lifting in the first stage. Several statistical analyses are used to evaluate the performance of the proposed system. The results indicate that it is a promising system in the applications of asynchronous BCI work.

Análisis del discurso asíncrono en la calidad de los aprendizajes esperados Asynchronous Discourse Analysis in the Quality of Expected Learning

Directory of Open Access Journals (Sweden)

Ana Elena Schalk Quintanar

2010-10-01

Full Text Available Las Universidades están implementando de forma progresiva procesos de formación virtual. Sin embargo, todavía resulta escasa la investigación que analiza los procesos internos en lo que se produce el aprendizaje en ambientes virtuales. En este artículo se presenta una investigación que busca describir la relación entre la calidad de la interacción, en los foros de discusión asincrónica en experiencias de formación en e-learning, y la calidad de los aprendizajes propuestos y logrados. El principal objetivo consistió en conocer, de qué forma las interacciones en los espacios virtuales, aportan calidad a los aprendizajes de los alumnos. Para ello se realizó un estudio descriptivo que combina una fase cualitativa y una cuantitativa, analizando más de 10.000 mensajes en 171 participantes de cuatro cursos de postgrado desarrollados en la modalidad de e-learning. Se analizó la comunicación asíncrona, a través de un sistema de categorías que contenía dimensiones sociales, cognitivas y didácticas del discurso on-line. Entre los resultados de la investigación se destaca una relación positiva entre la calidad y cantidad del discurso de los participantes y la calidad de los aprendizajes obtenidos y reflejados en las diferentes instancias de evaluación. Podemos concluir la necesidad de hacer un análisis, más allá del discurso escrito, para establecer relaciones con los aprendizajes tanto cognitivos como sociales de los alumnos. Por otra parte concluimos la necesidad de formar a los docentes para abordar los procesos de comunicación on-line.Universities are gradually implementing virtual learning processes. However, research still remains limited in examining the internal processes that occur in learning in virtual environments. This article presents an investigation that seeks to describe the relationship between the quality of interaction in asynchronous discussion forums in training experiences in e-learning, and the quality of

Frenetic Bounds on the Entropy Production

Science.gov (United States)

Maes, Christian

2017-10-01

We give a systematic derivation of positive lower bounds for the expected entropy production (EP) rate in classical statistical mechanical systems obeying a dynamical large deviation principle. The logic is the same for the return to thermodynamic equilibrium as it is for steady nonequilibria working under the condition of local detailed balance. We recover there recently studied "uncertainty" relations for the EP, appearing in studies about the effectiveness of mesoscopic machines. In general our refinement of the positivity of the expected EP rate is obtained in terms of a positive and even function of the expected current(s) which measures the dynamical activity in the system, a time-symmetric estimate of the changes in the system's configuration. Also underdamped diffusions can be included in the analysis.

Sum rates of asynchronous GFDMA and SC-FDMA for 5G uplink

Directory of Open Access Journals (Sweden)

Woojin Park

2015-12-01

Full Text Available The fifth generation (5G of mobile communication envisions ultralow latency less than 1 ms for radio interface. To this end, frameless asynchronous multiple access may be needed to allow users to transmit instantly without waiting for the next frame start. In this paper, generalized frequency division multiple-access (GFDMA, one of the promising multiple-access candidates for 5G mobile, is compared with the conventional single-carrier FDMA (SC-FDMA in terms of the uplink sum rate when both techniques are adapted for the asynchronous scenario. In particular, a waveform windowing technique is applied to both schemes to mitigate the inter-user interference due to non-zero out-of-band emission.

High-speed asynchronous optical sampling for high-sensitivity detection of coherent phonons

International Nuclear Information System (INIS)

Dekorsy, T; Taubert, R; Hudert, F; Schrenk, G; Bartels, A; Cerna, R; Kotaidis, V; Plech, A; Koehler, K; Schmitz, J; Wagner, J

2007-01-01

A new optical pump-probe technique is implemented for the investigation of coherent acoustic phonon dynamics in the GHz to THz frequency range which is based on two asynchronously linked femtosecond lasers. Asynchronous optical sampling (ASOPS) provides the performance of on all-optical oscilloscope and allows us to record optically induced lattice dynamics over nanosecond times with femtosecond resolution at scan rates of 10 kHz without any moving part in the set-up. Within 1 minute of data acquisition time signal-to-noise ratios better than 10 7 are achieved. We present examples of the high-sensitivity detection of coherent phonons in superlattices and of the coherent acoustic vibration of metallic nanoparticles

Right-Hand Side Dependent Bounds for GMRES Applied to Ill-Posed Problems

KAUST Repository

Pestana, Jennifer

2014-01-01

© IFIP International Federation for Information Processing 2014. In this paper we apply simple GMRES bounds to the nearly singular systems that arise in ill-posed problems. Our bounds depend on the eigenvalues of the coefficient matrix, the right-hand side vector and the nonnormality of the system. The bounds show that GMRES residuals initially decrease, as residual components associated with large eigenvalues are reduced, after which semi-convergence can be expected because of the effects of small eigenvalues.

Refining an asynchronous telerehabilitation platform for speech-language pathology: Engaging end-users in the process

Directory of Open Access Journals (Sweden)

Annie Jane Hill

2016-12-01

Full Text Available Asynchronous telerehabilitation in which computer-based interventions are remotely monitored and adapted offline is an emerging service delivery model in the rehabilitation of communication disorders. The asynchronous nature of this model may hold a benefit over its synchronous counterpart by eliminating scheduling issues and thus improving efficiency in a healthcare landscape of constrained resource allocation. The design of asynchronous telerehabilitation platforms should therefore ensure efficiency and flexibility. The authors have been engaged in a program of research to develop and evaluate an asynchronous telerehabilitation platform for use in speech-language pathology. eSALT is a novel asynchronous telerehabilitation platform in which clinicians design and individualize therapy tasks for upload to a client’s mobile device. An inbuilt telerehabilitation module allows for remote monitoring and updating of tasks. This paper introduces eSALT and reports outcomes from an usability study that considered the needs of two end-user groups, people with aphasia and clinicians, in the on-going refinement of eSALT. In the study participants with aphasia were paired with clinicians who used eSALT to design and customize therapy tasks. After training on the mobile device the participants engaged in therapy at home for a period of three weeks, while clinicians remotely monitored and updated tasks. Following the home trial, participants and clinicians engaged in semi-structured interviews and completed surveys on the usability of eSALT and their satisfaction with the platform. Content analysis of data involving five participants and three clinicians revealed a number of usability themes including ease of use, user support, satisfaction, limitations and potential improvements. These findings were translated into a number of refinements of the eSALT platform including the development of a client interface for use on the Apple iPad®, greater variety in

The aspect of vector control using the asynchronous traction motor in locomotives

Directory of Open Access Journals (Sweden)

L. Liudvinavičius

2009-12-01

Full Text Available The article examines curves controlling asynchronous traction motors increasingly used in locomotive electric drives the main task of which is to create a tractive effort-speed curve of an ideal locomotive Fk = f(v, including a hyperbolic area the curve of which will create conditions showing that energy created by the diesel engine of diesel locomotives (electric locomotives and in case of electric trains, electricity taken from the contact network over the entire range of locomotive speed is turned into efficient work. Mechanical power on wheel sets is constant Pk = Fkv = const, the power of the diesel engine is fully used over the entire range of locomotive speed. Tractive effort-speed curve Fk(v shows the dependency of locomotive traction power Fk on movement speed v. The article presents theoretical and practical aspects relevant to creating the structure of locomotive electric drive and selecting optimal control that is especially relevant to creating the structure of locomotive electric drive using ATM (asynchronous traction motor that gains special popularity in traction rolling stock replacing DC traction motors having low reliability. The frequency modes of asynchronous motor speed regulation are examined. To control ATM, the authors suggest the method of vector control presenting the structural schemes of a locomotive with ATM and control algorithm.

Asynchronous Cholinergic Drive Correlates with Excitation-Inhibition Imbalance via a Neuronal Ca2+ Sensor Protein

Directory of Open Access Journals (Sweden)

Keming Zhou

2017-05-01

Full Text Available Excitation-inhibition imbalance in neural networks is widely linked to neurological and neuropsychiatric disorders. However, how genetic factors alter neuronal activity, leading to excitation-inhibition imbalance, remains unclear. Here, using the C. elegans locomotor circuit, we examine how altering neuronal activity for varying time periods affects synaptic release pattern and animal behavior. We show that while short-duration activation of excitatory cholinergic neurons elicits a reversible enhancement of presynaptic strength, persistent activation results to asynchronous and reduced cholinergic drive, inducing imbalance between endogenous excitation and inhibition. We find that the neuronal calcium sensor protein NCS-2 is required for asynchronous cholinergic release in an activity-dependent manner and dampens excitability of inhibitory neurons non-cell autonomously. The function of NCS-2 requires its Ca2+ binding and membrane association domains. These results reveal a synaptic mechanism implicating asynchronous release in regulation of excitation-inhibition balance.

Asynchronous online foresight panels: the case of wildfire management

Science.gov (United States)

David N. Bengston; Robert L. Olson

2015-01-01

Text-based asynchronous online conferencing involves structured online discussion and deliberation among multiple participants from multiple sites in which there is a delay in interaction between contributors. This method has been widely used for a variety of purposes in higher education and other settings, but has not been commonly used in futures research. This paper...

Students experiences with collaborative learning in asynchronous computer-supported collaborative learning environments.

NARCIS (Netherlands)

Dewiyanti, Silvia; Brand-Gruwel, Saskia; Jochems, Wim; Broers, Nick

2008-01-01

Dewiyanti, S., Brand-Gruwel, S., Jochems, W., & Broers, N. (2007). Students experiences with collaborative learning in asynchronous computer-supported collaborative learning environments. Computers in Human Behavior, 23, 496-514.

Reconceptualising Moderation in Asynchronous Online Discussions Using Grounded Theory

Science.gov (United States)

Vlachopoulos, Panos; Cowan, John

2010-01-01

This article reports a grounded theory study of the moderation of asynchronous online discussions, to explore the processes by which tutors in higher education decide when and how to moderate. It aims to construct a theory of e-moderation based on some key factors which appear to influence e-moderation. It discusses previous research on the…

How to share concurrent asynchronous wait-free variables: Preliminary version

NARCIS (Netherlands)

M. Li (Ming); P.M.B. Vitányi (Paul)

1989-01-01

textabstractWe use a structured top-down approach to develop algorithms for atomic variables shared by concurrent asynchronous wait-free processes, starting from the problem specification. By this design we obtain a better understanding of what the algorithms do, why they do it, and that they

Developing a Successful Asynchronous Online Extension Program for Forest Landowners

Science.gov (United States)

Zobrist, Kevin W.

2014-01-01

Asynchronous online Extension classes can reach a wide audience, is convenient for the learner, and minimizes ongoing demands on instructor time. However, producing such classes takes significant effort up front. Advance planning and good communication with contributors are essential to success. Considerations include delivery platforms, content…

Bilirubin bound to cells does not form photoisomers

International Nuclear Information System (INIS)

Christensen, T.; Kinn, G.

1993-01-01

Cultured cells from one human and one murine cell line were incubated with bilirubin by different methods that allowed bilirubin to be bound to cells. The cells were irradiated with visible light of different wavelengths. Bilirubin bound to human serum albumin was also irradiated with light. After irradiation, bilirubin and its photoisomers were extracted and analyzed by HPLC. No photoisomers were found in samples of irradiated cells, while the types and amounts of photoisomers that were expected from the literature were found in samples of irradiated bilirubin/albumin mixtures. It is concluded that the formation of therapeutically active photoisomers during phototherapy most probably does not take place in skin cells, but most likely in bilirubin bound to albumin in the vessels or in the interstitial space. 16 refs., 2 figs

Asynchronous teaching of psychomotor skills through VR annotations: evaluation in digital rectal examination.

Science.gov (United States)

Rissanen, Mikko J; Kume, Naoto; Kuroda, Yoshihiro; Kuroda, Tomohiro; Yoshimura, Koji; Yoshihara, Hiroyuki

2008-01-01

Many VR technology based training systems use expert's motion data as the training aid, but would not provide any short-cut to teaching medical skills that do not depend on exact motions. Earlier we presented Annotated Simulation Records (ASRs), which can be used to encapsulate experts' insight on psychomotor skills. Annotations made to behavioural parameters in training simulators enable asynchronous teaching instead of just motion training in a proactive way to the learner. We evaluated ASRs for asynchronous teaching of Digital Rectal Examination (DRE) with 3 urologists and 8 medical students. The ASRs were found more effective than motion-based training with verbal feedback.

Ultra Low Energy FDSOI Asynchronous Reconfiguration Network for Adaptive Circuits

Directory of Open Access Journals (Sweden)

Soundous Chairat

2017-05-01

Full Text Available This paper introduces a plug-and-play on-chip asynchronous communication network aimed at the dynamic reconfiguration of a low-power adaptive circuit such as an internet of things (IoT system. By using a separate communication network, we can address both digital and analog blocks at a lower configuration cost, increasing the overall system power efficiency. As reconfiguration only occurs according to specific events and has to be automatically in stand-by most of the time, our design is fully asynchronous using handshake protocols. The paper presents the circuit’s architecture, performance results, and an example of the reconfiguration of frequency locked loops (FLL to validate our work. We obtain an overall energy per bit of 0.07 pJ/bit for one stage, in a 28 nm Fully Depleted Silicon On Insulator (FDSOI technology at 0.6 V and a 1.1 ns/bit latency per stage.

Algebraic Number Precoded OFDM Transmission for Asynchronous Cooperative Multirelay Networks

Directory of Open Access Journals (Sweden)

Hua Jiang

2014-01-01

Full Text Available This paper proposes a space-time block coding (STBC transmission scheme for asynchronous cooperative systems. By combination of rotated complex constellations and Hadamard transform, these constructed codes are capable of achieving full cooperative diversity with the analysis of the pairwise error probability (PEP. Due to the asynchronous characteristic of cooperative systems, orthogonal frequency division multiplexing (OFDM technique with cyclic prefix (CP is adopted for combating timing delays from relay nodes. The total transmit power across the entire network is fixed and appropriate power allocation can be implemented to optimize the network performance. The relay nodes do not require decoding and demodulation operation, resulting in a low complexity. Besides, there is no delay for forwarding the OFDM symbols to the destination node. At the destination node the received signals have the corresponding STBC structure on each subcarrier. In order to reduce the decoding complexity, the sphere decoder is implemented for fast data decoding. Bit error rate (BER performance demonstrates the effectiveness of the proposed scheme.

Involving the users remotely: an exploratory study using asynchronous usability testing

Directory of Open Access Journals (Sweden)

Beth Filar Williams

2015-02-01

Full Text Available Open Educational Resources (OER are increasingly used in the higher education landscape as a solution for a variety of copyright, publishing and cost-prohibiting issues. While OERs are becoming more common, reports of usability tests that evaluate how well learners can use them to accomplish their learning tasks have lagged behind. Because both the researchers and the learners in this study use resources and tools remotely, asynchronous usability testing of a prototype OER and MOOC online guide was conducted with an exploratory group of users to determine the guide’s ease of use for two distinct groups of users: Educators and Learners. In this article, we share the background and context of this usability project, suggest best methods for asynchronous remote usability testing, and share challenges and insights of the process and results of the testing

Asynchronous Group Review of EFL Writing: Interactions and Text Revisions

Science.gov (United States)

Saeed, Murad Abdu; Ghazali, Kamila

2017-01-01

The current paper reports an empirical study of asynchronous online group review of argumentative essays among nine English as foreign language (EFL) Arab university learners joining English in their first, second, and third years at the institution. In investigating online interactions, commenting patterns, and how the students facilitate text…

Multithreaded Asynchronous Graph Traversal for In-Memory and Semi-External Memory

KAUST Repository

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

2010-01-01

. Our highly parallel asynchronous approach hides data latency due to both poor locality and delays in the underlying graph data storage. We present an experimental study applying our technique to both In-Memory and Semi-External Memory graphs utilizing

Massive Asynchronous Parallelization of Sparse Matrix Factorizations

Energy Technology Data Exchange (ETDEWEB)

Chow, Edmond [Georgia Inst. of Technology, Atlanta, GA (United States)

2018-01-08

Solving sparse problems is at the core of many DOE computational science applications. We focus on the challenge of developing sparse algorithms that can fully exploit the parallelism in extreme-scale computing systems, in particular systems with massive numbers of cores per node. Our approach is to express a sparse matrix factorization as a large number of bilinear constraint equations, and then solving these equations via an asynchronous iterative method. The unknowns in these equations are the matrix entries of the factorization that is desired.

Formation of the wide asynchronous binary asteroid population

International Nuclear Information System (INIS)

Jacobson, Seth A.; Scheeres, Daniel J.; McMahon, Jay

2014-01-01

We propose and analyze a new mechanism for the formation of the wide asynchronous binary population. These binary asteroids have wide semimajor axes relative to most near-Earth and main belt asteroid systems. Confirmed members have rapidly rotating primaries and satellites that are not tidally locked. Previously suggested formation mechanisms from impact ejecta, from planetary flybys, and directly from rotational fission events cannot satisfy all of the observations. The newly hypothesized mechanism works as follows: (1) these systems are formed from rotational fission, (2) their satellites are tidally locked, (3) their orbits are expanded by the binary Yarkovsky-O'Keefe-Radzievskii-Paddack (BYORP) effect, (4) their satellites desynchronize as a result of the adiabatic invariance between the libration of the secondary and the mutual orbit, and (5) the secondary avoids resynchronization because of the YORP effect. This seemingly complex chain of events is a natural pathway for binaries with satellites that have particular shapes, which define the BYORP effect torque that acts on the system. After detailing the theory, we analyze each of the wide asynchronous binary members and candidates to assess their most likely formation mechanism. Finally, we suggest possible future observations to check and constrain our hypothesis.

Generalized surface tension bounds in vacuum decay

Science.gov (United States)

Masoumi, Ali; Paban, Sonia; Weinberg, Erick J.

2018-02-01

Coleman and De Luccia (CDL) showed that gravitational effects can prevent the decay by bubble nucleation of a Minkowski or AdS false vacuum. In their thin-wall approximation this happens whenever the surface tension in the bubble wall exceeds an upper bound proportional to the difference of the square roots of the true and false vacuum energy densities. Recently it was shown that there is another type of thin-wall regime that differs from that of CDL in that the radius of curvature grows substantially as one moves through the wall. Not only does the CDL derivation of the bound fail in this case, but also its very formulation becomes ambiguous because the surface tension is not well defined. We propose a definition of the surface tension and show that it obeys a bound similar in form to that of the CDL case. We then show that both thin-wall bounds are special cases of a more general bound that is satisfied for all bounce solutions with Minkowski or AdS false vacua. We discuss the limit where the parameters of the theory attain critical values and the bound is saturated. The bounce solution then disappears and a static planar domain wall solution appears in its stead. The scalar field potential then is of the form expected in supergravity, but this is only guaranteed along the trajectory in field space traced out by the bounce.

Pedagogical dimensions of effective online asynchronous teacher communication in higher education

NARCIS (Netherlands)

Smits, A.; Voogt, J.; Rutledge, D.; Slykhuis, D.

2015-01-01

In this research teacher behaviour in online asynchronous discussions is studied. To this end teachers’ online messages were analyzed and correlated to measures of student satisfaction. Findings show a positive relation between student satisfaction and the presence of content knowledge, multiple

Students' Learning in Asynchronous Discussion Forums: A Meta-Analysis

Science.gov (United States)

Martono, Fkipuntan; Salam, Urai

2017-01-01

Asynchronous discussion forums are among the most preferred tools chosen to foster learning opportunities and knowledge construction. To reveal the cognitive engagement evidenced in the transcripts of the discussion forums, this study presents 51 papers. 17 papers reported research on students' attitude toward the use of ICT for learning, 16…

Clonal expansion and linear genome evolution through breast cancer progression from pre-invasive stages to asynchronous metastasis

DEFF Research Database (Denmark)

Krøigård, Anne Bruun; Larsen, Martin Jakob; Lænkholm, Anne Vibeke

2015-01-01

Evolution of the breast cancer genome from pre-invasive stages to asynchronous metastasis is complex and mostly unexplored, but highly demanded as it may provide novel markers for and mechanistic insights in cancer progression. The increasing use of personalized therapy of breast cancer necessita......Evolution of the breast cancer genome from pre-invasive stages to asynchronous metastasis is complex and mostly unexplored, but highly demanded as it may provide novel markers for and mechanistic insights in cancer progression. The increasing use of personalized therapy of breast cancer...... progression from one breast cancer patient, including two different regions of Ductal Carcinoma In Situ (DCIS), primary tumor and an asynchronous metastasis. We identify a remarkable landscape of somatic mutations, retained throughout breast cancer progression and with new mutational events emerging at each...

Wind generator based on cascade connection of two asynchronized synchronous machines

International Nuclear Information System (INIS)

Dzhagarov, N.; Dzhagarova, Yu.

2000-01-01

A model of a wind generator with two asynchronized synchronous machines presented and different regimes are investigated. The analysis shows that the suggested scheme of a brushless generator works and has more advantages (reliability, easy for operation) in comparison with the known ones

An Asynchronous Time-Division-Multiplexed Network-on-Chip for Real-Time Systems

DEFF Research Database (Denmark)

Kasapaki, Evangelia

is an important part of the T-CREST paltform and used in a number of configurations. The flexible timing organization of Argo combines asynchronous routers with mesochronous NIs, which are connected to individually clocked cores, supporting a GALS system organization. The mesochronous NIs operate at the same......Multi-processor architectures using networks-on-chip (NOCs) for communication are becoming the standard approach in the development of embedded systems and general purpose platforms. Typically, multi-processor platforms follow a globally asynchronous locally synchronous (GALS) timing organization....... This thesis focuses on the design of Argo, a NOC targeted at hard real-time multi-processor platforms with a GALS timing organization. To support real-time communication, NOCs establish end-to-end connections and provide latency and throughput guarantees for these connections. Argo uses time division...

Fluka studies of the Asynchronous Beam Dump Effects on LHC Point 6

CERN Document Server

Versaci, R; Goddard, B; Mereghetti, A; Schmidt, R; Vlachoudis, V; CERN. Geneva. ATS Department

2011-01-01

The LHC is a record-breaking machine for beam energy and intensity. An intense effort has therefore been deployed in simulating critical operational scenarios of energy deposition. Using FLUKA Monte Carlo simulations, we have investigated the effects of an asynchronous beam dump at the LHC Point 6 where beams, with a stored energy of 360 MJ, can instantaneously release up to a few J cm^-3 in the cryogenic magnets which have a quench limit of the order of the mJ cm^-3. In the present paper we will describe the simulation approach, and discuss the evaluated maximum energy release onto the superconducting magnets during an asynchronous beam dump. We will then analyze the shielding provided by collimators installed in the area and discuss safety limits for the operation of the LHC.

An Asynchronous Multi-Sensor Micro Control Unit for Wireless Body Sensor Networks (WBSNs

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Ching-Hsing Luo

2011-07-01

Full Text Available In this work, an asynchronous multi-sensor micro control unit (MCU core is proposed for wireless body sensor networks (WBSNs. It consists of asynchronous interfaces, a power management unit, a multi-sensor controller, a data encoder (DE, and an error correct coder (ECC. To improve the system performance and expansion abilities, the asynchronous interface is created for handshaking different clock domains between ADC and RF with MCU. To increase the use time of the WBSN system, a power management technique is developed for reducing power consumption. In addition, the multi-sensor controller is designed for detecting various biomedical signals. To prevent loss error from wireless transmission, use of an error correct coding technique is important in biomedical applications. The data encoder is added for lossless compression of various biomedical signals with a compression ratio of almost three. This design is successfully tested on a FPGA board. The VLSI architecture of this work contains 2.68-K gate counts and consumes power 496-μW at 133-MHz processing rate by using TSMC 0.13-μm CMOS process. Compared with the previous techniques, this work offers higher performance, more functions, and lower hardware cost than other micro controller designs.

A Methodology for the Design and Verification of Globally Asynchronous/Locally Synchronous Architectures

Science.gov (United States)

Miller, Steven P.; Whalen, Mike W.; O'Brien, Dan; Heimdahl, Mats P.; Joshi, Anjali

2005-01-01

Recent advanced in model-checking have made it practical to formally verify the correctness of many complex synchronous systems (i.e., systems driven by a single clock). However, many computer systems are implemented by asynchronously composing several synchronous components, where each component has its own clock and these clocks are not synchronized. Formal verification of such Globally Asynchronous/Locally Synchronous (GA/LS) architectures is a much more difficult task. In this report, we describe a methodology for developing and reasoning about such systems. This approach allows a developer to start from an ideal system specification and refine it along two axes. Along one axis, the system can be refined one component at a time towards an implementation. Along the other axis, the behavior of the system can be relaxed to produce a more cost effective but still acceptable solution. We illustrate this process by applying it to the synchronization logic of a Dual Fight Guidance System, evolving the system from an ideal case in which the components do not fail and communicate synchronously to one in which the components can fail and communicate asynchronously. For each step, we show how the system requirements have to change if the system is to be implemented and prove that each implementation meets the revised system requirements through modelchecking.

An Asynchronous P300 BCI With SSVEP-Based Control State Detection

DEFF Research Database (Denmark)

Panicker, Rajesh C.; Puthusserypady, Sadasivan; Sun, Ying

2011-01-01

In this paper, an asynchronous brain–computer interface (BCI) system combining the P300 and steady-state visually evoked potentials (SSVEPs) paradigms is proposed. The information transfer is accomplished using P300 event-related potential paradigm and the control state (CS) detection is achieved...

A Scalable Multicore Architecture With Heterogeneous Memory Structures for Dynamic Neuromorphic Asynchronous Processors (DYNAPs).

Science.gov (United States)

Moradi, Saber; Qiao, Ning; Stefanini, Fabio; Indiveri, Giacomo

2018-02-01

Neuromorphic computing systems comprise networks of neurons that use asynchronous events for both computation and communication. This type of representation offers several advantages in terms of bandwidth and power consumption in neuromorphic electronic systems. However, managing the traffic of asynchronous events in large scale systems is a daunting task, both in terms of circuit complexity and memory requirements. Here, we present a novel routing methodology that employs both hierarchical and mesh routing strategies and combines heterogeneous memory structures for minimizing both memory requirements and latency, while maximizing programming flexibility to support a wide range of event-based neural network architectures, through parameter configuration. We validated the proposed scheme in a prototype multicore neuromorphic processor chip that employs hybrid analog/digital circuits for emulating synapse and neuron dynamics together with asynchronous digital circuits for managing the address-event traffic. We present a theoretical analysis of the proposed connectivity scheme, describe the methods and circuits used to implement such scheme, and characterize the prototype chip. Finally, we demonstrate the use of the neuromorphic processor with a convolutional neural network for the real-time classification of visual symbols being flashed to a dynamic vision sensor (DVS) at high speed.

Study of a centrifugal pump, asynchronous motor and inverter, using ...

African Journals Online (AJOL)

The signals generated by the micro controller have been used to program the parallel port of a computer. By reading the recorded bits of the parallel port in LabVIEW software, the signals from the micro controller have been restored and made available to the simulation model of the three-phase inverter, asynchronous ...

1 Commande multivariable du moteur asynchrone triphasé à cage ...

African Journals Online (AJOL)

AKA BOKO

Correspondance, courriel : rabenarivo.michel@yahoo.fr. Résumé. La commande du moteur asynchrone triphasé à ... synthèse du système à l'aide du logiciel MATLAB. Mots-clés : commande, système multivariable, variation de ... of the system by MATLAB software. Keywords : control, MIMO system, frequency variation, ...

Forced synchronization and asynchronous quenching in a thermo-acoustic system

Science.gov (United States)

Mondal, Sirshendu; Pawar, Samadhan A.; Sujith, Raman

2017-11-01

Forced synchronization, which has been extensively studied in theory and experiments, occurs through two different mechanisms known as phase locking and asynchronous quenching. The latter indicates the suppression of oscillation amplitude. In most practical combustion systems such as gas turbine engines, the main concern is high amplitude pressure oscillations, known as thermo-acoustic instability. Thermo-acoustic instability is undesirable and needs to be suppressed because of its damaging consequences to an engine. In the present study, a systematic experimental investigation of forced synchronization is performed in a prototypical thermo-acoustic system, a Rijke tube, in its limit cycle operation. Further, we show a qualitatively similar behavior using a reduced order model. In the phase locking region, the simultaneous occurrence of synchronization and resonant amplification leads to high amplitude pressure oscillations. However, a reduction in the amplitude of natural oscillations by about 78% of the unforced amplitude is observed when the forcing frequency is far lower than the natural frequency. This shows the possibility of suppression of the oscillation amplitude through asynchronous quenching in thermo-acoustic systems.

Isolation of TRPV1 independent mechanisms of spontaneous and asynchronous glutamate release at primary afferent to NTS synapses.

Directory of Open Access Journals (Sweden)

Axel J. Fenwick

2014-01-01

Full Text Available Cranial visceral afferents contained within the solitary tract (ST contact second-order neurons in the nucleus of the solitary tract (NTS and release the excitatory amino acid glutamate via three distinct exocytosis pathways; synchronous, asynchronous, and spontaneous release. The presence of TRPV1 in the central terminals of a majority of ST afferents conveys activity-dependent asynchronous glutamate release and provides a temperature sensitive calcium conductance which largely determines the rate of spontaneous vesicle fusion. TRPV1 is present in unmyelinated C-fiber afferents and these facilitated forms of glutamate release may underlie the relative strength of C-fibers in activating autonomic reflex pathways. However, pharmacological blockade of TRPV1 signaling eliminates only ~50% of the asynchronous profile and attenuates the temperature sensitivity of spontaneous release indicating additional thermosensitive calcium influx pathways may exist which mediate these forms of vesicle release. In the present study we isolate the contribution of TRPV1 independent forms of glutamate release at ST-NTS synapses. We found ST afferent innervation at NTS neurons and synchronous vesicle release from TRPV1 KO mice was not different to control animals; however, only half of TRPV1 KO ST afferents completely lacked asynchronous glutamate release. Further, temperature driven spontaneous rates of vesicle release were not different from 33˚ - 37˚C between control and TRPV1 KO afferents. These findings suggest additional temperature dependent mechanisms controlling asynchronous and thermosensitive spontaneous release at physiological temperatures, possibly mediated by additional thermosensitive TRP channels in primary afferent terminals.

Asynchronous social search as a single point of access to information

NARCIS (Netherlands)

Buijs, M.P.; Spruit, M.

2017-01-01

The purpose of this paper is to present asynchronous social search as a novel and intuitive approach to search for information in which people collaborate to find the information they are looking for. Design/methodology/approach A prototype was built to test the feasibility in a business

Commande adaptive d'une machine asynchrone

Science.gov (United States)

Slama-Belkhodja, I.; de Fornel, B.

1996-06-01

The paper deals with an indirect self-tuning speed control for an induction motor supplied by a chopper-filter-inverter system. Input/Output models are identified with the recursive least squares algorithm and the controller adaptation is based on a pole assignement strategy. Emphasis is put on the evaluation of the parameter identification in order to avoid instabilities because of disturbances or insufficient excitations. This is especially of importance when the adaptive control is carried out in closed loop systems and without additional test signals. Simulation results show the improvement of the dynamic responses and the robustness against load variations or parameters variations (rotor resistance, inertia). Cat article décrit une stratégie de commande adaptive indirecte à Placement de Pôles (PP), appliquée à la commande en vitesse d'une machine asynchrone alimentée par un ensemble hacheur-filtre-onduleur de tension. L'algorithme des Moindres Carrés Récursifs (MCR) est utilisé pour l'identification des modèles de comportement type entrées/sorties. Un intérêt particulier est porté à la mise en oeuvre de cet algorithme et à la discussion de ses résultats, tenant compte des erreurs de modélisation et de la nature peu riche en excitations des entrées du processus. Différents régimes transitoires ont été simulés pour apprécier l'apport de cette association (MCR-PP) : démarrages et inversion des sens de rotation, à vide et en charges, applications d'échelons de couple résistant, variations paramétriques. Les résultats permettent d'illustrer, tant au niveau des performances que de la robustesse, l'apport d'une telle commande adaptive pour des entraînements électriques avec une machine asynchrone.

Asynchronous data change notification between database server and accelerator control systems

International Nuclear Information System (INIS)

Wenge Fu; Seth Nemesure; Morris, J.

2012-01-01

Database data change notification (DCN) is a commonly used feature, it allows to be informed when the data has been changed on the server side by another client. Not all database management systems (DBMS) provide an explicit DCN mechanism. Even for those DBMS's which support DCN (such as Oracle and MS SQL server), some server side and/or client side programming may be required to make the DCN system work. This makes the setup of DCN between database server and interested clients tedious and time consuming. In accelerator control systems, there are many well established software client/server architectures (such as CDEV, EPICS, and ADO) that can be used to implement data reflection servers that transfer data asynchronously to any client using the standard SET/GET API. This paper describes a method for using such a data reflection server to set up asynchronous DCN (ADCN) between a DBMS and clients. This method works well for all DBMS systems which provide database trigger functionality. (authors)

Simulation models of a drive with an asynchronous electric engine for students of electrical engineering faculties

Directory of Open Access Journals (Sweden)

Romanenko N. G.

2017-10-01

Full Text Available the application of virtual laboratories will allow to show different transition processes, as well as to carry out experiments that are very expensive in real electrical machines’ labs, for example, to calculate the energy costs in electric drives. Models of non-regulation asynchronous drive and frequency-regulated asynchronous electric drive are examined in this article. The author has calculated and compared the energy losses of these systems with various types of loads and this lets us to evaluate work processes of many technical devices.

Heterogeneity, Bounded Rationality and Market Dysfunctionality

OpenAIRE

Xue-Zhong He; Lei Shi

2008-01-01

As the main building blocks of the modern finance theory, homogeneity and rational expectation have faced difficulty in explaining many market anomalies, stylized factors, and market inefficiency in empirical studies. As a result, heterogeneity and bounded rationality have been used as an alterative paradigm of asset price dynamics and this paradigm has been widely recognized recently in both academic and financial market practitioners. Within the framework of Chiarella, Dieci and He (2006a, ...

Application of Artificial Intelligence Techniques for the Control of the Asynchronous Machine

Directory of Open Access Journals (Sweden)

F. Khammar

2016-01-01

Full Text Available The induction machine is experiencing a growing success for two decades by gradually replacing the DC machines and synchronous in many industrial applications. This paper is devoted to the study of advanced methods applied to the command of the asynchronous machine in order to obtain a system of control of high performance. While the criteria for response time, overtaking, and static error can be assured by the techniques of conventional control, the criterion of robustness remains a challenge for researchers. This criterion can be satisfied only by applying advanced techniques of command. After mathematical modeling of the asynchronous machine, it defines the control strategies based on the orientation of the rotor flux. The results of the different simulation tests highlight the properties of robustness of algorithms proposed and suggested to compare the different control strategies.

Asynchronous Sensor fuSion for Improved Safety of air Traffic (ASSIST), Phase I

Data.gov (United States)

National Aeronautics and Space Administration — SSCI proposes to develop, implement and test a collision detection system for unmanned aerial vehicles (UAV), referred to as the Asynchronous Sensor fuSion for...

Teleoperation system using Asynchronous transfer mode, ATM network

International Nuclear Information System (INIS)

Mohd Dani Baba; A Nasoruddin Mohamad

1999-01-01

This paper examines the application of Asynchronous Transfer Mode (ATM) in a distributed industrial environment such as in teleoperation, which performs real time control manipulation from a remote location. In our study, two models of teleoperation are proposed; the first model is a point to point connection and the second model is through an ATM network. The performance results are analysed as to determine whether the two models can support the teleoperation traffics via simulation using commercial software design tool. (Author)

Resignation syndrome: Catatonia? Culture-bound?

Directory of Open Access Journals (Sweden)

Karl eSallin

2016-01-01

Full Text Available Resignation syndrome (RS designates a long-standing disorder predominately affecting psychologically traumatised children and adolescents in the midst of a strenuous and lengthy migration process. Typically a depressive onset is followed by gradual withdrawal progressing via stupor into a state that prompts tube feeding and is characterised by failure to respond even to painful stimuli. The patient is seemingly unconscious. Recovery ensues within months to years and is claimed to be dependent on the restoration of hope to the family.Descriptions of disorders resembling RS can be found in the literature and the condition is unlikely novel. Nevertheless, the magnitude and geographical distribution stand out. Several hundred cases have been reported exclusively in Sweden in the past decade prompting the Swedish National Board of Health and Welfare to recognise RS as a separate diagnostic entity. The currently prevailing stress hypothesis fails to account for the regional distribution and contributes little to treatment. Consequently, a re-evaluation of diagnostics and treatment is required. Psychogenic catatonia is proposed to supply the best fit with the clinical presentation. Treatment response, altered brain metabolism or preserved awareness would support this hypothesis.Epidemiological data suggests culture-bound beliefs and expectations to generate and direct symptom expression and we argue that culture-bound psychogenesis can accommodate the endemic distribution.Last, we review recent models of predictive coding indicating how expectation processes are crucially involved in the placebo and nocebo effect, delusions and conversion disorders. Building on this theoretical framework we propose a neurobiological model of RS in which the impact of overwhelming negative expectations are directly causative of the down-regulation of higher order and lower order behavioural systems in particularly vulnerable individuals.

Merging the Forces of Asynchronous Tutoring and Synchronous Conferencing: A Qualitative Study of Arab ESL Academic Writers Using E-Tutoring

Science.gov (United States)

Alqadoumi, Omar Mohamed

2012-01-01

Previous studies in the field of e-tutoring dealt either with asynchronous tutoring or synchronous conferencing as modes for providing e-tutoring services to English learners. This qualitative research study reports the experiences of Arab ESL tutees with both asynchronous tutoring and synchronous conferencing. It also reports the experiences of…

Model for Investigation of Operational Wind Power Plant Regimes with Doubly–Fed Asynchronous Machine in Power System

Directory of Open Access Journals (Sweden)

R. I. Mustafayev

2012-01-01

Full Text Available The paper presents methodology for mathematical modeling of power system (its part when jointly operated with wind power plants (stations that contain asynchronous doubly-fed machines used as generators. The essence and advantage of the methodology is that it allows efficiently to mate equations of doubly-fed asynchronous machines, written in the axes that rotate with the machine rotor speed with the equations of external electric power system, written in synchronously rotating axes.

Sharp Bounds by Probability-Generating Functions and Variable Drift

DEFF Research Database (Denmark)

Doerr, Benjamin; Fouz, Mahmoud; Witt, Carsten

2011-01-01

We introduce to the runtime analysis of evolutionary algorithms two powerful techniques: probability-generating functions and variable drift analysis. They are shown to provide a clean framework for proving sharp upper and lower bounds. As an application, we improve the results by Doerr et al....... (GECCO 2010) in several respects. First, the upper bound on the expected running time of the most successful quasirandom evolutionary algorithm for the OneMax function is improved from 1.28nln n to 0.982nlnn, which breaks the barrier of nln n posed by coupon-collector processes. Compared to the classical...

Flipping the Online Classroom with Web 2.0: The Asynchronous Workshop

Science.gov (United States)

Cummings, Lance

2016-01-01

This article examines how Web 2.0 technologies can be used to "flip" the online classroom by creating asynchronous workshops in social environments where immediacy and social presence can be maximized. Using experience teaching several communication and writing classes in Google Apps (Google+, Google Hangouts, Google Drive, etc.), I…

Reactors: A data-oriented synchronous/asynchronous programming model for distributed applications

DEFF Research Database (Denmark)

Field, John; Marinescu, Maria-Cristina; Stefansen, Christian Oskar Erik

2009-01-01

of messages. Similarly, the interface to a reactor is simply its state, rather than a collection of message channels, ports, or methods. One novel feature of our model is the ability to compose behaviors both synchronously and asynchronously. Also, our use of Datalog-style rules allows aspect-like composition...

Cooperative Learning in Graduate Student Projects: Comparing Synchronous versus Asynchronous Collaboration

Science.gov (United States)

Strang, Kenneth

2013-01-01

Cooperative learning was applied in a graduate project management course to compare the effectiveness of asynchronous versus synchronous online team meetings. An experiment was constructed to allocate students to project teams while ensuring there was a balance of requisite skills, namely systems analysis and design along with HTML/Javascript…

Defining the Symmetry of the Universal Semi-Regular Autonomous Asynchronous Systems

Directory of Open Access Journals (Sweden)

Serban E. Vlad

2012-02-01

Full Text Available The regular autonomous asynchronous systems are the non-deterministic Boolean dynamical systems and universality means the greatest in the sense of the inclusion. The paper gives four definitions of symmetry of these systems in a slightly more general framework, called semi-regularity, and also many examples.

An improved asynchronous brain interface: making use of the temporal history of the LF-ASD feature vectors

Science.gov (United States)

Bashashati, Ali; Mason, Steve; Ward, Rabab K.; Birch, Gary E.

2006-06-01

The low-frequency asynchronous switch design (LF-ASD) has been introduced as a direct brain interface (BI) for asynchronous control applications. Asynchronous interfaces, as opposed to synchronous interfaces, have the advantage of being operational at all times and not only at specific system-defined periods. This paper modifies the LF-ASD design by incorporating into the system more knowledge about the attempted movements. Specifically, the history of feature values extracted from the EEG signal is used to detect a right index finger movement attempt. Using data collected from individuals with high-level spinal cord injuries and able-bodied subjects, it is shown that the error characteristics of the modified design are significantly better than the previous LF-ASD design. The true positive rate percentage increased by up to 15 which corresponds to 50% improvement when the system is operating with false positive rates in the 1-2% range.

Determining sociability, social space, and social presence in (a)synchronous collaborating groups

NARCIS (Netherlands)

Kreijns, C.J.; Kirschner, P.A.; Jochems, W.M.G.; Buuren, van H.

2004-01-01

The effectiveness of group learning in asynchronous distributed learning groups depends on the social interaction that takes place. This social interaction affects both cognitive and socioemotional processes that take place during learning, group forming, establishment of group structures, and group

Determining sociability, social space, and social presence in (A)synchronous collaborative groups

NARCIS (Netherlands)

Kreijns, K.; Kirschner, P.A.; Jochems, W.; Buuren, H. van

2004-01-01

The effectiveness of group learning in asynchronous distributed learning groups depends on the social interaction that takes place. This social interaction affects both cognitive and socioemotional processes that take place during learning, group forming, establishment of group structures, and group

Upper Higgs boson mass bounds from a chirally invariant lattice Higgs-Yukawa Model

Energy Technology Data Exchange (ETDEWEB)

Gerhold, P. [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; John von Neumann-Institut fuer Computing NIC/DESY, Zeuthen (Germany); Jansen, K. [John von Neumann-Institut fuer Computing NIC/DESY, Zeuthen (Germany)

2010-02-15

We establish the cutoff-dependent upper Higgs boson mass bound by means of direct lattice computations in the framework of a chirally invariant lattice Higgs-Yukawa model emulating the same chiral Yukawa coupling structure as in the Higgs-fermion sector of the Standard Model. As expected from the triviality picture of the Higgs sector, we observe the upper mass bound to decrease with rising cutoff parameter {lambda}. Moreover, the strength of the fermionic contribution to the upper mass bound is explored by comparing to the corresponding analysis in the pure {phi}{sup 4}-theory. (orig.)

Direct detection of dark matter bound to the Earth

DEFF Research Database (Denmark)

Catena, Riccardo; Kouvaris, Chris

2017-01-01

We study the properties and direct detection prospects of an as of yet neglected population of dark matter (DM) particles moving in orbits gravitationally bound to the Earth. This DM population is expected to form via scattering by nuclei in the Earth's interior. We compute fluxes and nuclear...

Computer Learner Corpora: Analysing Interlanguage Errors in Synchronous and Asynchronous Communication

Science.gov (United States)

MacDonald, Penny; Garcia-Carbonell, Amparo; Carot, Sierra, Jose Miguel

2013-01-01

This study focuses on the computer-aided analysis of interlanguage errors made by the participants in the telematic simulation IDEELS (Intercultural Dynamics in European Education through on-Line Simulation). The synchronous and asynchronous communication analysed was part of the MiLC Corpus, a multilingual learner corpus of texts written by…

An Examination of Computer Engineering Students' Perceptions about Asynchronous Discussion Forums

Science.gov (United States)

Ozyurt, Ozcan; Ozyurt, Hacer

2013-01-01

This study was conducted in order to reveal the usage profiles and perceptions of Asynchronous Discussion Forums (ADFs) of 126 computer engineering students from the Computer Engineering Department in a university in Turkey. By using a mixed methods research design both quantitative and qualitative data were collected and analyzed. Research…

Simulation of the Dynamic Behavior of an Asynchronous Machine Using Direct Self-Control

Directory of Open Access Journals (Sweden)

Cristian Paul Chioncel

2007-01-01

Full Text Available The paper presents the major steps that have to be gone for the implementation of the mathematical model of the asynchronous machine in SciLab / Scicos. This implemented ASM model, will be used to check the dynamic behavior of the system, the current diagrams as well as the behavior motor speed and the torque, if the input signal has a pulsation form. This implementation’s are made in Scilab / Scicos environment, a clone of the MATLAB, which provides number-crunching power similar to MATLAB, at a much better cost/performance ratio. The implemented model offers the possibility to analyze the behaviors of the asynchronous machine in different dynamic situations: speed, torques, current in motor or generator regime and to study its behavior in different possible control schemes.

Asynchronous Gossip-Based Gradient-Free Method for Multiagent Optimization

OpenAIRE

Deming Yuan

2014-01-01

This paper considers the constrained multiagent optimization problem. The objective function of the problem is a sum of convex functions, each of which is known by a specific agent only. For solving this problem, we propose an asynchronous distributed method that is based on gradient-free oracles and gossip algorithm. In contrast to the existing work, we do not require that agents be capable of computing the subgradients of their objective functions and coordinating their...

The queueing perspective of asynchronous network coding in two-way relay network

Science.gov (United States)

Liang, Yaping; Chang, Qing; Li, Xianxu

2018-04-01

Asynchronous network coding (NC) has potential to improve the wireless network performance compared with a routing or the synchronous network coding. Recent researches concentrate on the optimization between throughput/energy consuming and delay with a couple of independent input flow. However, the implementation of NC requires a thorough investigation of its impact on relevant queueing systems where few work focuses on. Moreover, few works study the probability density function (pdf) in network coding scenario. In this paper, the scenario with two independent Poisson input flows and one output flow is considered. The asynchronous NC-based strategy is that a new arrival evicts a head packet holding in its queue when waiting for another packet from the other flow to encode. The pdf for the output flow which contains both coded and uncoded packets is derived. Besides, the statistic characteristics of this strategy are analyzed. These results are verified by numerical simulations.

Synaptotagmin-7 is an asynchronous calcium sensor for synaptic transmission in neurons expressing SNAP-23.

Directory of Open Access Journals (Sweden)

Jens P Weber

Full Text Available Synchronization of neurotransmitter release with the presynaptic action potential is essential for maintaining fidelity of information transfer in the central nervous system. However, synchronous release is frequently accompanied by an asynchronous release component that builds up during repetitive stimulation, and can even play a dominant role in some synapses. Here, we show that substitution of SNAP-23 for SNAP-25 in mouse autaptic glutamatergic hippocampal neurons results in asynchronous release and a higher frequency of spontaneous release events (mEPSCs. Use of neurons from double-knock-out (SNAP-25, synaptotagmin-7 mice in combination with viral transduction showed that SNAP-23-driven release is triggered by endogenous synaptotagmin-7. In the absence of synaptotagmin-7 release became even more asynchronous, and the spontaneous release rate increased even more, indicating that synaptotagmin-7 acts to synchronize release and suppress spontaneous release. However, compared to synaptotagmin-1, synaptotagmin-7 is a both leaky and asynchronous calcium sensor. In the presence of SNAP-25, consequences of the elimination of synaptotagmin-7 were small or absent, indicating that the protein pairs SNAP-25/synaptotagmin-1 and SNAP-23/synaptotagmin-7 might act as mutually exclusive calcium sensors. Expression of fusion proteins between pHluorin (pH-sensitive GFP and synaptotagmin-1 or -7 showed that vesicles that fuse using the SNAP-23/synaptotagmin-7 combination contained synaptotagmin-1, while synaptotagmin-7 barely displayed activity-dependent trafficking between vesicle and plasma membrane, implying that it acts as a plasma membrane calcium sensor. Overall, these findings support the idea of alternative syt∶SNARE combinations driving release with different kinetics and fidelity.

Bounds for nonlinear composites via iterated homogenization

Science.gov (United States)

Ponte Castañeda, P.

2012-09-01

Improved estimates of the Hashin-Shtrikman-Willis type are generated for the class of nonlinear composites consisting of two well-ordered, isotropic phases distributed randomly with prescribed two-point correlations, as determined by the H-measure of the microstructure. For this purpose, a novel strategy for generating bounds has been developed utilizing iterated homogenization. The general idea is to make use of bounds that may be available for composite materials in the limit when the concentration of one of the phases (say phase 1) is small. It then follows from the theory of iterated homogenization that it is possible, under certain conditions, to obtain bounds for more general values of the concentration, by gradually adding small amounts of phase 1 in incremental fashion, and sequentially using the available dilute-concentration estimate, up to the final (finite) value of the concentration (of phase 1). Such an approach can also be useful when available bounds are expected to be tighter for certain ranges of the phase volume fractions. This is the case, for example, for the "linear comparison" bounds for porous viscoplastic materials, which are known to be comparatively tighter for large values of the porosity. In this case, the new bounds obtained by the above-mentioned "iterated" procedure can be shown to be much improved relative to the earlier "linear comparison" bounds, especially at low values of the porosity and high triaxialities. Consistent with the way in which they have been derived, the new estimates are, strictly, bounds only for the class of multi-scale, nonlinear composites consisting of two well-ordered, isotropic phases that are distributed with prescribed H-measure at each stage in the incremental process. However, given the facts that the H-measure of the sequential microstructures is conserved (so that the final microstructures can be shown to have the same H-measure), and that H-measures are insensitive to length scales, it is conjectured

Asynchronous Task-Based Polar Decomposition on Manycore Architectures

KAUST Repository

Sukkari, Dalal

2016-10-25

This paper introduces the first asynchronous, task-based implementation of the polar decomposition on manycore architectures. Based on a new formulation of the iterative QR dynamically-weighted Halley algorithm (QDWH) for the calculation of the polar decomposition, the proposed implementation replaces the original and hostile LU factorization for the condition number estimator by the more adequate QR factorization to enable software portability across various architectures. Relying on fine-grained computations, the novel task-based implementation is also capable of taking advantage of the identity structure of the matrix involved during the QDWH iterations, which decreases the overall algorithmic complexity. Furthermore, the artifactual synchronization points have been severely weakened compared to previous implementations, unveiling look-ahead opportunities for better hardware occupancy. The overall QDWH-based polar decomposition can then be represented as a directed acyclic graph (DAG), where nodes represent computational tasks and edges define the inter-task data dependencies. The StarPU dynamic runtime system is employed to traverse the DAG, to track the various data dependencies and to asynchronously schedule the computational tasks on the underlying hardware resources, resulting in an out-of-order task scheduling. Benchmarking experiments show significant improvements against existing state-of-the-art high performance implementations (i.e., Intel MKL and Elemental) for the polar decomposition on latest shared-memory vendors\\' systems (i.e., Intel Haswell/Broadwell/Knights Landing, NVIDIA K80/P100 GPUs and IBM Power8), while maintaining high numerical accuracy.

A Parallel Particle Swarm Optimization Algorithm Accelerated by Asynchronous Evaluations

Science.gov (United States)

Venter, Gerhard; Sobieszczanski-Sobieski, Jaroslaw

2005-01-01

A parallel Particle Swarm Optimization (PSO) algorithm is presented. Particle swarm optimization is a fairly recent addition to the family of non-gradient based, probabilistic search algorithms that is based on a simplified social model and is closely tied to swarming theory. Although PSO algorithms present several attractive properties to the designer, they are plagued by high computational cost as measured by elapsed time. One approach to reduce the elapsed time is to make use of coarse-grained parallelization to evaluate the design points. Previous parallel PSO algorithms were mostly implemented in a synchronous manner, where all design points within a design iteration are evaluated before the next iteration is started. This approach leads to poor parallel speedup in cases where a heterogeneous parallel environment is used and/or where the analysis time depends on the design point being analyzed. This paper introduces an asynchronous parallel PSO algorithm that greatly improves the parallel e ciency. The asynchronous algorithm is benchmarked on a cluster assembled of Apple Macintosh G5 desktop computers, using the multi-disciplinary optimization of a typical transport aircraft wing as an example.

Bound-Electron Nonlinearity Beyond the Ionization Threshold

Science.gov (United States)

Wahlstrand, J. K.; Zahedpour, S.; Bahl, A.; Kolesik, M.; Milchberg, H. M.

2018-05-01

We present absolute space- and time-resolved measurements of the ultrafast laser-driven nonlinear polarizability in argon, krypton, xenon, nitrogen, and oxygen up to ionization fractions of a few percent. These measurements enable determination of the strongly nonperturbative bound-electron nonlinear polarizability well beyond the ionization threshold, where it is found to remain approximately quadratic in the laser field, a result normally expected at much lower intensities where perturbation theory applies.

Beyond Social Presence: Facelessness and the Ethics of Asynchronous Online Education

Science.gov (United States)

Rose, Ellen

2017-01-01

In this position paper, I argue that a focus on achieving and increasing social presence in online courses tends to derail a consideration of the ethical implications and dimensions of the essential facelessness of asynchronous education. Drawing upon the work of Emmanuel Levinas and Nel Noddings, who contended that the face is the basis of…

Asynchronous monitoring of the quality of multilevel optical PAM signals

Science.gov (United States)

Siuzdak, J.

2017-08-01

In the paper, there is analyzed the signal quality assessment method based on delay tap asynchronous sampling, both for binary and multilevel PAM signals. The obtained multilevel phase diagrams are far more complicated than binary ones. The phase diagrams are affected by the signal distortions but it is difficult to relate reliably the phase diagram form to the distortion type and its influence on the signal quality.

Asynchronous data-driven classification of weapon systems

International Nuclear Information System (INIS)

Jin, Xin; Mukherjee, Kushal; Gupta, Shalabh; Ray, Asok; Phoha, Shashi; Damarla, Thyagaraju

2009-01-01

This communication addresses real-time weapon classification by analysis of asynchronous acoustic data, collected from microphones on a sensor network. The weapon classification algorithm consists of two parts: (i) feature extraction from time-series data using symbolic dynamic filtering (SDF), and (ii) pattern classification based on the extracted features using the language measure (LM) and support vector machine (SVM). The proposed algorithm has been tested on field data, generated by firing of two types of rifles. The results of analysis demonstrate high accuracy and fast execution of the pattern classification algorithm with low memory requirements. Potential applications include simultaneous shooter localization and weapon classification with soldier-wearable networked sensors. (rapid communication)

Circuit lower bounds in bounded arithmetics

Czech Academy of Sciences Publication Activity Database

Pich, Ján

2015-01-01

Roč. 166, č. 1 (2015), s. 29-45 ISSN 0168-0072 R&D Projects: GA AV ČR IAA100190902 Keywords : bounded arithmetic * circuit lower bounds Subject RIV: BA - General Mathematics Impact factor: 0.582, year: 2015 http://www.sciencedirect.com/science/article/pii/S0168007214000888

Non-fragile switched H∞ control for morphing aircraft with asynchronous switching

Directory of Open Access Journals (Sweden)

Haoyu CHENG

2017-06-01

Full Text Available This paper deals with the problem of non-fragile linear parameter-varying (LPV H∞ control for morphing aircraft with asynchronous switching. The switched LPV model of morphing aircraft is established by Jacobian linearization approach according to the nonlinear model. The data missing is taken into account in the link from sensors to controllers and the link from controllers to actuators, which satisfies Bernoulli distribution. The non-fragile switched LPV controllers are constructed with consideration of the uncertainties of controllers and asynchronous switching phenomenon. The parameter-dependent Lyapunov functional method and mode-dependent average dwell time (MDADT method are combined to guarantee the stability and prescribed performance of the system. The sufficient conditions on the solvability of the problem are derived in the form of linear matrix inequalities (LMI. In order to achieve higher efficiency of the designing process, an algorithm is applied to divide the whole set into subsets automatically. Simulation results are provided to verify the effectiveness and superiority of the method in the paper.

From discrete-time models to continuous-time, asynchronous modeling of financial markets

NARCIS (Netherlands)

Boer, Katalin; Kaymak, Uzay; Spiering, Jaap

2007-01-01

Most agent-based simulation models of financial markets are discrete-time in nature. In this paper, we investigate to what degree such models are extensible to continuous-time, asynchronous modeling of financial markets. We study the behavior of a learning market maker in a market with information

From Discrete-Time Models to Continuous-Time, Asynchronous Models of Financial Markets

NARCIS (Netherlands)

K. Boer-Sorban (Katalin); U. Kaymak (Uzay); J. Spiering (Jaap)

2006-01-01

textabstractMost agent-based simulation models of financial markets are discrete-time in nature. In this paper, we investigate to what degree such models are extensible to continuous-time, asynchronous modelling of financial markets. We study the behaviour of a learning market maker in a market with

Cultural Influences on Chinese Students' Asynchronous Online Learning in a Canadian University

Science.gov (United States)

Zhao, Naxin; McDougall, Douglas

2008-01-01

This study explored six Chinese graduate students' asynchronous online learning in a large urban Canadian university. Individual interviews in Mandarin elicited their perceptions of online learning, their participation in it, and the cultural factors that influenced their experiences. In general, the participants had a positive attitude towards…

FLUKA Studies of the Asynchronous Beam Dump Effects on LHC Point 6

CERN Document Server

Versaci, R; Goddard, B; Schmidt, R; Vlachoudis, V; Mereghetti, A

2011-01-01

The LHC is a record-breaking machine for beam energy and intensity. An intense effort has therefore been deployed in simulating critical operational scenarios of energy deposition. FLUKA is the most widely used code for this kind of simulations at CERN because of the high reliability of its results and the ease to custom detailed simulations all along hundreds of meters of beam line. We have investigated the effects of an asynchronous beam dump on the LHC Point 6 where, beams with a stored energy of 360 MJ, can instantaneously release up to a few J cm−3 in the cryogenic magnets which have a quench limit of the order of the mJ cm−3. In the present paper we will describe the simulation approach, and discuss the evaluated maximum energy release onto the superconducting magnets during an asynchronous beam dump. We will then analyse the shielding provided by collimators installed in the area and discuss safety limits for the operation of the LHC.

HiggsBounds-4. Improved tests of extended Higgs sectors against exclusion bounds from LEP, the Tevatron and the LHC

Energy Technology Data Exchange (ETDEWEB)

Bechtle, Philip [Bonn Univ. (Germany). Physikalisches Inst.; Heinemeyer, Sven [Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain); Staal, Oscar [Stockholm Univ. (Sweden). Dept. of Physics; Stefaniak, Tim; Williams, Karina E. [Bonn Univ. (Germany). Physikalisches Inst.; Bonn Univ. (Germany). Bethe Center for Theoretical Physics; Weiglein, Georg [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Brein, Oliver

2013-12-15

We describe the new developments in version 4 of the public computer code HiggsBounds. HiggsBounds is a tool to test models with arbitrary Higgs sectors, containing both neutral and charged Higgs bosons, against the published exclusion bounds from Higgs searches at the LEP, Tevatron and LHC experiments. From the model predictions for the Higgs masses, branching ratios, production cross sections and total decay widths - which are specified by the user in the input for the program - the code calculates the predicted signal rates for the search channels considered in the experimental data. The signal rates are compared to the expected and observed cross section limits from the Higgs searches to determine whether a point in the model parameter space is excluded at 95% confidence level. In this paper we present a modification of the HiggsBounds main algorithm that extends the exclusion test in order to ensure that it provides useful results in the presence of one or more significant excesses in the data, corresponding to potential Higgs signals. We also describe a new method to test whether the limits from an experimental search performed under certain model assumptions can be applied to a different theoretical model. Further developments discussed here include a framework to take into account theoretical uncertainties on the Higgs mass predictions, and the possibility to obtain the {chi}{sup 2} likelihood of Higgs exclusion limits from LEP. Extensions to the user subroutines from earlier versions of HiggsBounds are described. The new features are demonstrated by additional example programs.

HiggsBounds-4. Improved tests of extended Higgs sectors against exclusion bounds from LEP, the Tevatron and the LHC

International Nuclear Information System (INIS)

Bechtle, Philip; Staal, Oscar; Brein, Oliver

2013-12-01

We describe the new developments in version 4 of the public computer code HiggsBounds. HiggsBounds is a tool to test models with arbitrary Higgs sectors, containing both neutral and charged Higgs bosons, against the published exclusion bounds from Higgs searches at the LEP, Tevatron and LHC experiments. From the model predictions for the Higgs masses, branching ratios, production cross sections and total decay widths - which are specified by the user in the input for the program - the code calculates the predicted signal rates for the search channels considered in the experimental data. The signal rates are compared to the expected and observed cross section limits from the Higgs searches to determine whether a point in the model parameter space is excluded at 95% confidence level. In this paper we present a modification of the HiggsBounds main algorithm that extends the exclusion test in order to ensure that it provides useful results in the presence of one or more significant excesses in the data, corresponding to potential Higgs signals. We also describe a new method to test whether the limits from an experimental search performed under certain model assumptions can be applied to a different theoretical model. Further developments discussed here include a framework to take into account theoretical uncertainties on the Higgs mass predictions, and the possibility to obtain the χ 2 likelihood of Higgs exclusion limits from LEP. Extensions to the user subroutines from earlier versions of HiggsBounds are described. The new features are demonstrated by additional example programs.

Accelerator physics studies on the effects from an asynchronous beam dump onto the LHC experimental region collimators

CERN Document Server

Lari, L; Boccone, V; Bruce, R; Cerutti, F; Rossi, A; Vlachoudis, V; Mereghetti, A; Faus-Golfe, A

2012-01-01

Asynchronous beam aborts at the LHC are estimated to occur on average once per year. Accelerator physics studies of asynchronous dumps have been performed at different beam energies and beta-stars. The loss patterns are analyzed in order to identify the losses in particular on the Phase 1 Tertiary Collimators (TCT), since their tungsten-based active jaw insert has a lower damage threshold than the carbon-based other LHC collimators. Settings of the tilt angle of the TCTs are discussed with the aim of reducing the thermal loads on the TCT themselves.

Transition to Asynchronous Transfer Mode (ATM) an Implementation Model for NPS Software Metrics Lab

National Research Council Canada - National Science Library

Carney, Cameron

1999-01-01

With Asynchronous Transfer Mode (ATM), we are experiencing the emergence of a network technology that has the potential of satisfying the requirement for a worldwide standard to allow interoperability of information, regardless...

Investigation of a photo-voltaic pump station with asynchronous electric drive

International Nuclear Information System (INIS)

Dzhagarov, N.; Vladimirov, P.

2000-01-01

A scheme of a photo-voltaic pump station with constant current drive is presented. The requirements for reliability and minimal maintenance necessitate the use of asynchronous drive which has been studied. The studies of the system's model for various regimes show its adequacy. The model can be used for determination of the optimal conditions providing maximal working efficiency

Synchronous and Asynchronous Communication in Distance Learning: A Review of the Literature

Science.gov (United States)

Watts, Lynette

2016-01-01

Distance learning is commonplace in higher education, with increasing numbers of students enjoying the flexibility e-learning provides. Keeping students connected with peers and instructors has been a challenge with e-learning, but as technology has advanced, the methods by which educators keep students engaged, synchronously and asynchronously,…

Synchronization, retiming and OTDM of an asynchronous 10 Gigabit Ethernet NRZ packet using a time lens for Terabit Ethernet

DEFF Research Database (Denmark)

Hu, Hao; Laguardia Areal, Janaina; Mulvad, Hans Christian Hansen

2011-01-01

An asynchronous 10G Ethernet packet is synchronized and retimed to a master clock using a time lens. The NRZ packet is converted into an RZ packet and multiplexed with a serial 1.28 Tb/s signal.......An asynchronous 10G Ethernet packet is synchronized and retimed to a master clock using a time lens. The NRZ packet is converted into an RZ packet and multiplexed with a serial 1.28 Tb/s signal....

Computing variational bounds for flow through random aggregates of Spheres

International Nuclear Information System (INIS)

Berryman, J.G.

1983-01-01

Known formulas for variational bounds on Darcy's constant for slow flow through porous media depend on two-point and three-poiint spatial correlation functions. Certain bounds due to Prager and Doi depending only a two-point correlation functions have been calculated for the first time for random aggregates of spheres with packing fractions (eta) up to eta = 0.64. Three radial distribution functions for hard spheres were tested for eta up to 0.49: (1) the uniform distribution or ''well-stirred approximation,'' (2) the Percus Yevick approximation, and (3) the semi-empirical distribution of Verlet and Weis. The empirical radial distribution functions of Benett andd Finney were used for packing fractions near the random-close-packing limit (eta/sub RCP/dapprox.0.64). An accurate multidimensional Monte Carlo integration method (VEGAS) developed by Lepage was used to compute the required two-point correlation functions. The results show that Doi's bounds are preferred for eta>0.10 while Prager's bounds are preferred for eta>0.10. The ''upper bounds'' computed using the well-stirred approximation actually become negative (which is physically impossible) as eta increases, indicating the very limited value of this approximation. The other two choices of radial distribution function give reasonable results for eta up to 0.49. However, these bounds do not decrease with eta as fast as expected for large eta. It is concluded that variational bounds dependent on three-point correlation functions are required to obtain more accurate bounds on Darcy's constant for large eta

Evolution of asynchronous motor activity in paired muscles: effects of ecology, morphology, and phylogeny.

Science.gov (United States)

Gerry, Shannon P; Ramsay, Jason B; Dean, Mason N; Wilga, Cheryl D

2008-08-01

Many studies of feeding behavior have implanted electrodes unilaterally (in muscles on only one side of the head) to determine the basic motor patterns of muscles controlling the jaws. However, bilateral implantation has the potential to achieve a more comprehensive understanding of modification of the motor activity that may be occurring between the left and right sides of the head. In particular, complex processing of prey is often characterized by bilaterally asynchronous and even unilateral activation of the jaw musculature. In this study, we bilaterally implant feeding muscles in species from four orders of elasmobranchs (Squaliformes, Orectolobiformes, Carcharhiniformes, Rajoidea) in order to characterize the effects of type of prey, feeding behavior, and phylogeny on the degree of asynchronous muscle activation. Electrodes were implanted in three of the jaw adductors, two divisions of the quadratomandibularis and the preorbitalis, as well as in a cranial elevator in sharks, the epaxialis. The asynchrony of feeding events (measured as the degree to which activity of members of a muscle pair is out of phase) was compared across species for capture versus processing and simple versus complex prey, then interpreted in the contexts of phylogeny, morphology, and ecology to clarify determinants of asynchronous activity. Whereas capture and processing of prey were characterized by statistically similar degrees of asynchrony for data pooled across species, events involving complex prey were more asynchronous than were those involving simple prey. The two trophic generalists, Squalus acanthias and Leucoraja erinacea, modulated the degree of asynchrony according to type of prey, whereas the two behavioral specialists, Chiloscyllium plagiosum and Mustelus canis, activated the cranial muscles synchronously regardless of type of prey. These differences in jaw muscle activity would not have been detected with unilateral implantation. Therefore, we advocate bilateral

The impact of asynchronous online course design for professional development on science-teacher self-efficacy

Science.gov (United States)

Long, Caryn L. Smith

This dissertation examines how various designs of asynchronous online courses for teacher professional development may impact science-teacher self-efficacy. Mayer's studies, providing the cognitive theory of multimedia learning, targeted designs of asynchronous online learning and the point where contributions of written, auditory, and visual information on these sites could cause cognitive overload (Mayer, 2005). With increasing usage of online resources for educators to gain teaching credits, understanding how to construct these professional development offerings is critical. Teacher self-efficacy can affect how well information from these courses relays to students in their classroom. This research explored the connection between online asynchronous professional development design and teacher self-efficacy through analysis of a physics-based course in three distinct course-design offerings, while collecting content-acquisition data and self-efficacy effects before and after participation. Results from this research showed teacher self-efficacy had improved in all online treatments which included a text-only, text and audio and text, audio and animation version of the same physics content. Content knowledge was most effected by the text-only and text and audio treatments with significan growth occurring in the remember, apply, and analyze levels of bloom's taxonomy. Due to the small number of participants, it cannot be said that these results are conclusive.

Simulation and Analysis of Autonomous Time Synchronization Based on Asynchronism Two-way Inter-satellite Link

Science.gov (United States)

Fang, L.; Yang, X. H.; Sun, B. Q.; Qin, W. J.; Kong, Y.

2013-09-01

The measurement of the inter-satellite link is one of the key techniques in the autonomous operation of satellite navigation system. Based on the asynchronism inter-satellite two-way measurement mode in GPS constellation, the reduction formula of the inter-satellite time synchronization is built in this paper. Moreover, the corrective method of main systematic errors is proposed. Inter-satellite two-way time synchronization is simulated on the basis of IGS (International GNSS Service) precise ephemeris. The impacts of the epoch domestication of asynchronism inter-satellite link pseudo-range, the initial orbit, and the main systematic errors on satellite time synchronization are analyzed. Furthermore, the broadcast clock error of each satellite is calculated by the ``centralized'' inter-satellite autonomous time synchronization. Simulation results show that the epoch domestication of asynchronism inter-satellite link pseudo-range and the initial orbit have little impact on the satellite clock errors, and thus they needn't be taken into account. The errors caused by the relativistic effect and the asymmetry of path travel have large impact on the satellite clock errors. These should be corrected with theoretical formula. Compared with the IGS precise clock error, the root mean square of the broadcast clock error of each satellite is about 0.4 ns.

Asynchronous Execution of the Fast Multipole Method Using Charm++

OpenAIRE

AbdulJabbar, Mustafa; Yokota, Rio; Keyes, David

2014-01-01

Fast multipole methods (FMM) on distributed mem- ory have traditionally used a bulk-synchronous model of com- municating the local essential tree (LET) and overlapping it with computation of the local data. This could be perceived as an extreme case of data aggregation, where the whole LET is communicated at once. Charm++ allows a much finer control over the granularity of communication, and has a asynchronous execution model that fits well with the structure of our FMM code. Unlike previous ...

Asynchronous and synchronous dual-wavelength pulse generation in a passively mode-locked fiber laser with a mode-locker.

Science.gov (United States)

Hu, Guoqing; Pan, Yingling; Zhao, Xin; Yin, Siyao; Zhang, Meng; Zheng, Zheng

2017-12-01

The evolution from asynchronous to synchronous dual-wavelength pulse generation in a passively mode-locked fiber laser is experimentally investigated by tailoring the intracavity dispersion. Through tuning the intracavity-loss-dependent gain profile and the birefringence-induced filter effect, asynchronous dual-wavelength soliton pulses can be generated until the intracavity anomalous dispersion is reduced to ∼8  fs/nm. The transition from asynchronous to synchronous pulse generation is then observed at an elevated pump power in the presence of residual anomalous dispersion, and it is shown that pulses are temporally synchronized at the mode-locker in the cavity. Spectral sidelobes are observed and could be attributed to the four-wave-mixing effect between dual-wavelength pulses at the carbon nanotube mode-locker. These results could provide further insight into the design and realization of such dual-wavelength ultrafast lasers for different applications such as dual-comb metrology as well as better understanding of the inter-pulse interactions in such dual-comb lasers.

Ultraheavy Yukawa-bound states of fourth-generation at Large ...

Indian Academy of Sciences (India)

2012-10-05

Oct 5, 2012 ... Abstract. A study of bound states of the fourth-generation quarks in the range of 500–700 GeV is presented, where the binding energies are expected to be mainly of Yukawa origin, with QCD subdominant. Near degeneracy of their masses exhibits a new 'isospin'. The production of a colour- octet, isosinglet ...

Diagnosis of hearing loss using automated audiometry in an asynchronous telehealth model: A pilot accuracy study.

Science.gov (United States)

Brennan-Jones, Christopher G; Eikelboom, Robert H; Swanepoel, De Wet

2017-02-01

Introduction Standard criteria exist for diagnosing different types of hearing loss, yet audiologists interpret audiograms manually. This pilot study examined the feasibility of standardised interpretations of audiometry in a telehealth model of care. The aim of this study was to examine diagnostic accuracy of automated audiometry in adults with hearing loss in an asynchronous telehealth model using pre-defined diagnostic protocols. Materials and methods We recruited 42 study participants from a public audiology and otolaryngology clinic in Perth, Western Australia. Manual audiometry was performed by an audiologist either before or after automated audiometry. Diagnostic protocols were applied asynchronously for normal hearing, disabling hearing loss, conductive hearing loss and unilateral hearing loss. Sensitivity and specificity analyses were conducted using a two-by-two matrix and Cohen's kappa was used to measure agreement. Results The overall sensitivity for the diagnostic criteria was 0.88 (range: 0.86-1) and overall specificity was 0.93 (range: 0.86-0.97). Overall kappa ( k) agreement was 'substantial' k = 0.80 (95% confidence interval (CI) 0.70-0.89) and significant at p loss. This method has the potential to improve synchronous and asynchronous tele-audiology service delivery.

Exploring effectiveness of team communication: Balancing synchronous and asynchronous communication in design teams

NARCIS (Netherlands)

Otter, den A.F.H.J.; Emmitt, S.

2007-01-01

Purpose – Effective teams use a balance of synchronous and asynchronous communication. Team communication is dependent on the communication acts of team members and the ability of managers to facilitate, stimulate and motivate them. Team members from organizations using different information systems

Learning about the Literacy Development of English Language Learners in Asynchronous Online Discussions

Science.gov (United States)

De Oliveira, Luciana C.; Olesova, Larisa

2013-01-01

This study examined asynchronous online discussions in the online course "English Language Development" to identify themes related to participants' learning about the language and literacy development of English Language Learners when they facilitated online discussions to determine whether the participants developed sufficient…

The effects on health behavior and health outcomes of Internet-based asynchronous communication between health providers and patients with a chronic condition: a systematic review.

Science.gov (United States)

de Jong, Catharina Carolina; Ros, Wynand Jg; Schrijvers, Guus

2014-01-16

In support of professional practice, asynchronous communication between the patient and the provider is implemented separately or in combination with Internet-based self-management interventions. This interaction occurs primarily through electronic messaging or discussion boards. There is little evidence as to whether it is a useful tool for chronically ill patients to support their self-management and increase the effectiveness of interventions. The aim of our study was to review the use and usability of patient-provider asynchronous communication for chronically ill patients and the effects of such communication on health behavior, health outcomes, and patient satisfaction. A literature search was performed using PubMed and Embase. The quality of the articles was appraised according to the National Institute for Health and Clinical Excellence (NICE) criteria. The use and usability of the asynchronous communication was analyzed by examining the frequency of use and the number of users of the interventions with asynchronous communication, as well as of separate electronic messaging. The effectiveness of asynchronous communication was analyzed by examining effects on health behavior, health outcomes, and patient satisfaction. Patients' knowledge concerning their chronic condition increased and they seemed to appreciate being able to communicate asynchronously with their providers. They not only had specific questions but also wanted to communicate about feeling ill. A decrease in visits to the physician was shown in two studies (P=.07, P=.07). Increases in self-management/self-efficacy for patients with back pain, dyspnea, and heart failure were found. Positive health outcomes were shown in 12 studies, where the clinical outcomes for diabetic patients (HbA1c level) and for asthmatic patients (forced expiratory volume [FEV]) improved. Physical symptoms improved in five studies. Five studies generated a variety of positive psychosocial outcomes. The effect of

Asynchronous Task-Based Polar Decomposition on Single Node Manycore Architectures

KAUST Repository

Sukkari, Dalal E.; Ltaief, Hatem; Faverge, Mathieu; Keyes, David E.

2017-01-01

This paper introduces the first asynchronous, task-based formulation of the polar decomposition and its corresponding implementation on manycore architectures. Based on a formulation of the iterative QR dynamically-weighted Halley algorithm (QDWH) for the calculation of the polar decomposition, the proposed implementation replaces the original LU factorization for the condition number estimator by the more adequate QR factorization to enable software portability across various architectures. Relying on fine-grained computations, the novel task-based implementation is capable of taking advantage of the identity structure of the matrix involved during the QDWH iterations, which decreases the overall algorithmic complexity. Furthermore, the artifactual synchronization points have been weakened compared to previous implementations, unveiling look-ahead opportunities for better hardware occupancy. The overall QDWH-based polar decomposition can then be represented as a directed acyclic graph (DAG), where nodes represent computational tasks and edges define the inter-task data dependencies. The StarPU dynamic runtime system is employed to traverse the DAG, to track the various data dependencies and to asynchronously schedule the computational tasks on the underlying hardware resources, resulting in an out-of-order task scheduling. Benchmarking experiments show significant improvements against existing state-of-the-art high performance implementations for the polar decomposition on latest shared-memory vendors' systems, while maintaining numerical accuracy.

Asynchronous Task-Based Polar Decomposition on Single Node Manycore Architectures

KAUST Repository

Sukkari, Dalal E.

2017-09-29

This paper introduces the first asynchronous, task-based formulation of the polar decomposition and its corresponding implementation on manycore architectures. Based on a formulation of the iterative QR dynamically-weighted Halley algorithm (QDWH) for the calculation of the polar decomposition, the proposed implementation replaces the original LU factorization for the condition number estimator by the more adequate QR factorization to enable software portability across various architectures. Relying on fine-grained computations, the novel task-based implementation is capable of taking advantage of the identity structure of the matrix involved during the QDWH iterations, which decreases the overall algorithmic complexity. Furthermore, the artifactual synchronization points have been weakened compared to previous implementations, unveiling look-ahead opportunities for better hardware occupancy. The overall QDWH-based polar decomposition can then be represented as a directed acyclic graph (DAG), where nodes represent computational tasks and edges define the inter-task data dependencies. The StarPU dynamic runtime system is employed to traverse the DAG, to track the various data dependencies and to asynchronously schedule the computational tasks on the underlying hardware resources, resulting in an out-of-order task scheduling. Benchmarking experiments show significant improvements against existing state-of-the-art high performance implementations for the polar decomposition on latest shared-memory vendors\\' systems, while maintaining numerical accuracy.

Perceptron Mistake Bounds

OpenAIRE

Mohri, Mehryar; Rostamizadeh, Afshin

2013-01-01

We present a brief survey of existing mistake bounds and introduce novel bounds for the Perceptron or the kernel Perceptron algorithm. Our novel bounds generalize beyond standard margin-loss type bounds, allow for any convex and Lipschitz loss function, and admit a very simple proof.

Asynchronous interaction, online technologies self-efficacy and self-regulated learning as predictors of academic achievement in an online class

Science.gov (United States)

McGhee, Rosie M. Hector

This research is a correlational study of the relationship among the independent variables: asynchronous interaction, online technologies self-efficacy, and self-regulated learning, and the dependent variable; academic achievement. This study involves an online computer literacy course at a local community college. Very little research exists on the relationship among asynchronous interaction, online technologies self-efficacy and self-regulated learning on predicting academic achievement in an online class. Liu (2008), in his study on student interaction in online courses, concluded that student interaction is a complex issue that needs more research to increase our understanding as it relates to distance education. The purpose of this study was to examine the relationships between asynchronous interaction, online technologies self-efficacy, self-regulated learning and academic achievement in an online computer literacy class at a community college. The researcher used quantitative methods to obtain and analyze data on the relationships among the variables during the summer 2010 semester. Forty-five community college students completed three web-based self-reporting instruments: (a) the GVU 10th WWW User Survey Questionnaire, (b) the Online Technologies Self-Efficacy Survey, and (c) selected items from the Motivated Strategies for Learning Questionnaire. Additional data was obtained from asynchronous discussions posted on Blackboard(TM) Learning Management System. The results of this study found that there were statistically significant relationships between asynchronous interaction and academic achievement (r = .55, p online technologies self-efficacy and academic achievement (r = .50, p online instructors, online course designers, faculty, students and others who are concerned about predictors for online students' success. Also, it serves as a foundation for future research and provides valuable information for educators interested in taking online teaching and

A Coding Scheme to Analyse the Online Asynchronous Discussion Forums of University Students

Science.gov (United States)

Biasutti, Michele

2017-01-01

The current study describes the development of a content analysis coding scheme to examine transcripts of online asynchronous discussion groups in higher education. The theoretical framework comprises the theories regarding knowledge construction in computer-supported collaborative learning (CSCL) based on a sociocultural perspective. The coding…

Theoretically Based Pedagogical Strategies Leading to Deep Learning in Asynchronous Online Gerontology Courses

Science.gov (United States)

Majeski, Robin; Stover, Merrily

2007-01-01

Online learning has enjoyed increasing popularity in gerontology. This paper presents instructional strategies grounded in Fink's (2003) theory of significant learning designed for the completely asynchronous online gerontology classroom. It links these components with the development of mastery learning goals and provides specific guidelines for…

The Mechanical Transient Process at Asynchronous Motor Oscillating Mode

Science.gov (United States)

Antonovičs, Uldis; Bražis, Viesturs; Greivulis, Jānis

2009-01-01

The research object is squirrel-cage asynchronous motor connected to single-phase sinusoidal. There are shown, that by connecting to the stator windings a certain sequence of half-period positive and negative voltage, a motor rotor is rotated, but three times slower than in the three-phase mode. Changing the connecting sequence of positive and negative half-period voltage to stator windings, motor can work in various oscillating modes. It is tested experimentally. The mechanical transient processes had been researched in rotation and oscillating modes.

Effects of synchronous versus asynchronous mode of propulsion on wheelchair basketball sprinting.

Science.gov (United States)

Faupin, Arnaud; Borel, Benoit; Meyer, Christophe; Gorce, Philippe; Watelain, Eric

2013-11-01

This study aimed to first investigate synchronous (SYN) versus asynchronous (ASY) mode of propulsion and, second, investigate the wheel camber effects on sprinting performance as well as temporal parameters. Seven wheelchair basketball players performed four maximal eight-second sprints on a wheelchair ergometer. They repeated the test according to two modes of propulsion (SYN and ASY) and two wheel cambers (9° and 15°). The mean maximal velocity and push power output was greater in the synchronous mode compared to the asynchronous mode for both camber angles. However, the fluctuation in the velocity profile is inferior for ASY versus SYN mode for both camber angles. Greater push time/cycle time (Pt/Ct) and arm frequency (AF) for synchronous mode versus asynchronous mode and inversely, lesser Ct and rest time (Rt) values for the synchronous mode, for which greater velocity were observed. SYN mode leads to better performance than ASY mode in terms of maximal propulsion velocity. However, ASY propulsion allows greater continuity of the hand-rim force application, reducing fluctuations in the velocity profile. The camber angle had no effect on ASY and SYN mean maximal velocity and push power output. The study of wheelchair propulsion strategies is important for better understanding physiological and biomechanical impacts of wheelchair propulsion for individuals with disabilities. From a kinematical point of view, this study highlights synchronous mode of propulsion to be more efficient, with regards to mean maximal velocity reaching during maximal sprinting exercises. Even if this study focuses on well-trained wheelchair athletes, results from this study could complement the knowledge on the physiological and biomechanical adaptations to wheelchair propulsion and therefore, might be interesting for wheelchair modifications for purposes of rehabilitation.

Distributed embedded controller development with petri nets application to globally-asynchronous locally-synchronous systems

CERN Document Server

Moutinho, Filipe de Carvalho

2016-01-01

This book describes a model-based development approach for globally-asynchronous locally-synchronous distributed embedded controllers.  This approach uses Petri nets as modeling formalism to create platform and network independent models supporting the use of design automation tools.  To support this development approach, the Petri nets class in use is extended with time-domains and asynchronous-channels. The authors’ approach uses models not only providing a better understanding of the distributed controller and improving the communication among the stakeholders, but also to be ready to support the entire lifecycle, including the simulation, the verification (using model-checking tools), the implementation (relying on automatic code generators), and the deployment of the distributed controller into specific platforms. Uses a graphical and intuitive modeling formalism supported by design automation tools; Enables verification, ensuring that the distributed controller was correctly specified; Provides flex...

Quorum system and random based asynchronous rendezvous protocol for cognitive radio ad hoc networks

Directory of Open Access Journals (Sweden)

Sylwia Romaszko

2013-12-01

Full Text Available This paper proposes a rendezvous protocol for cognitive radio ad hoc networks, RAC2E-gQS, which utilizes (1 the asynchronous and randomness properties of the RAC2E protocol, and (2 channel mapping protocol, based on a grid Quorum System (gQS, and taking into account channel heterogeneity and asymmetric channel views. We show that the combination of the RAC2E protocol with the grid-quorum based channel mapping can yield a powerful RAC2E-gQS rendezvous protocol for asynchronous operation in a distributed environment assuring a rapid rendezvous between the cognitive radio nodes having available both symmetric and asymmetric channel views. We also propose an enhancement of the protocol, which uses a torus QS for a slot allocation, dealing with the worst case scenario, a large number of channels with opposite ranking lists.

Evaluating the Quality of Interaction in Asynchronous Discussion Forums in Fully Online Courses

Science.gov (United States)

Nandi, Dip; Hamilton, Margaret; Harland, James

2012-01-01

Fully online courses are becoming progressively more popular because of their "anytime anywhere" learning flexibility. One of the ways students interact with each other and with the instructors within fully online learning environments is via asynchronous discussion forums. However, student engagement in online discussion forums does not…

Scalability of Several Asynchronous Many-Task Models for In Situ Statistical Analysis.

Energy Technology Data Exchange (ETDEWEB)

Pebay, Philippe Pierre [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Bennett, Janine Camille [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Kolla, Hemanth [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Borghesi, Giulio [Sandia National Lab. (SNL-CA), Livermore, CA (United States)

2017-05-01

This report is a sequel to [PB16], in which we provided a first progress report on research and development towards a scalable, asynchronous many-task, in situ statistical analysis engine using the Legion runtime system. This earlier work included a prototype implementation of a proposed solution, using a proxy mini-application as a surrogate for a full-scale scientific simulation code. The first scalability studies were conducted with the above on modestly-sized experimental clusters. In contrast, in the current work we have integrated our in situ analysis engines with a full-size scientific application (S3D, using the Legion-SPMD model), and have conducted nu- merical tests on the largest computational platform currently available for DOE science ap- plications. We also provide details regarding the design and development of a light-weight asynchronous collectives library. We describe how this library is utilized within our SPMD- Legion S3D workflow, and compare the data aggregation technique deployed herein to the approach taken within our previous work.

BER and total throughput of asynchronous DS-OCDMA/WDM systems with multiple user interference

OpenAIRE

Ghiringhelli, F.; Zervas, M.N.

2003-01-01

The BER and throughput of Direct-Sequence OCDMA/WDM systems based on quadripolar codes and superstructured fiber Bragg gratings are statistically derived under asynchronous operation, intensity detection, and Multiple User Interference. Performance improvements with Forward Error Correction are included.

Information flow vs resource access in the asynchronous pi-calculus.

OpenAIRE

HENNESSY, MATTHEW

2002-01-01

PUBLISHED We propose an extension of the asynchronous ?-calculus in which a variety of security properties may be captured using types. These are an extension of the input/output types for the ?-calculus in which I/O capabilities are assigned specific security levels. The main innovation is a uniform typing system that, by varying slightly the allowed set of types, captures different notions of security.We first define a typing system that ensures that processes running at security level ?...

Friend or foe? An exploratory study of Australian parents' use of asynchronous discussion boards in childhood obesity.

Science.gov (United States)

Appleton, Jessica; Fowler, Cathrine; Brown, Nicola

2014-01-01

The use of Internet and social media is increasing in every area of life. Parents are increasingly using online mediums to seek information about their children's health. Therefore, this is becoming an increasingly important topic area for health professionals to acknowledge. Developing an understanding about the dissemination of child health information through these online mediums will assist health professional to continue to engage and support parents to seek and share accurate and safe child health information. To explore parents' use of asynchronous online discussion boards for child health information seeking, advice and social support. A qualitative descriptive approach using an a priori template analysis was used to explore 34 discussions threads sampled from two Australian based online parenting discussion forums. To contain the scope of this study the threads chosen focused on childhood obesity in the Australian context. Four major themes related to parents' use of asynchronous online discussion boards were found. These were seeking advice, sharing advice, social support and making judgement. This final theme of making judgements included parents' perceptions of health professionals' advice. Asynchronous online discussion boards are online mediums being utilised for seeking and sharing child health related information and support between parents. The notion

Control or non-control state: that is the question! An asynchronous visual P300-based BCI approach

Science.gov (United States)

Pinegger, Andreas; Faller, Josef; Halder, Sebastian; Wriessnegger, Selina C.; Müller-Putz, Gernot R.

2015-02-01

Objective. Brain-computer interfaces (BCI) based on event-related potentials (ERP) were proven to be a reliable synchronous communication method. For everyday life situations, however, this synchronous mode is impractical because the system will deliver a selection even if the user is not paying attention to the stimulation. So far, research into attention-aware visual ERP-BCIs (i.e., asynchronous ERP-BCIs) has led to variable success. In this study, we investigate new approaches for detection of user engagement. Approach. Classifier output and frequency-domain features of electroencephalogram signals as well as the hybridization of them were used to detect the user's state. We tested their capabilities for state detection in different control scenarios on offline data from 21 healthy volunteers. Main results. The hybridization of classifier output and frequency-domain features outperformed the results of the single methods, and allowed building an asynchronous P300-based BCI with an average correct state detection accuracy of more than 95%. Significance. Our results show that all introduced approaches for state detection in an asynchronous P300-based BCI can effectively avoid involuntary selections, and that the hybrid method is the most effective approach.

Asynchronous variational integration using continuous assumed gradient elements.

Science.gov (United States)

Wolff, Sebastian; Bucher, Christian

2013-03-01

Asynchronous variational integration (AVI) is a tool which improves the numerical efficiency of explicit time stepping schemes when applied to finite element meshes with local spatial refinement. This is achieved by associating an individual time step length to each spatial domain. Furthermore, long-term stability is ensured by its variational structure. This article presents AVI in the context of finite elements based on a weakened weak form (W2) Liu (2009) [1], exemplified by continuous assumed gradient elements Wolff and Bucher (2011) [2]. The article presents the main ideas of the modified AVI, gives implementation notes and a recipe for estimating the critical time step.

Participation in asynchronous online discussion forums does improve student learning of gross anatomy.

Science.gov (United States)

Green, Rodney A; Farchione, Davide; Hughes, Diane L; Chan, Siew-Pang

2014-01-01

Asynchronous online discussion forums are common in blended learning models and are popular with students. A previous report has suggested that participation in these forums may assist student learning in a gross anatomy subject but it was unclear as to whether more academically able students post more often or whether participation led to improved learning outcomes. This study used a path model to analyze the contribution of forum participation, previous academic ability, and student campus of enrolment to final marks in a multicampus gross anatomy course for physiotherapy students. The course has a substantial online learning management system (LMS) that incorporates asynchronous forums as a learning tool, particularly to answer learning objectives. Students were encouraged to post new threads and answer queries in threads started by others. The forums were moderated weekly by staff. Discussion forums were the most used feature of the LMS site with 31,920 hits. Forty-eight percent of the students posted at least once with 186 threads initiated by students and a total of 608 posts. The total number of posts made a significant direct contribution to final mark (P = 0.008) as did previous academic ability (P = 0.002). Although campus did not contribute to final mark, there was a trend for students at the campus where the course coordinator was situated to post more often than those at the other campus (P = 0.073). These results indicate that asynchronous online discussion forums can be an effective tool for improving student learning outcomes as evidenced by final marks in gross anatomy teaching. Copyright © 2013 American Association of Anatomists.

Synaptotagmin-7 Is an Asynchronous Calcium Sensor for Synaptic Transmission in Neurons Expressing SNAP-23

DEFF Research Database (Denmark)

Weber, Jens P; Toft-Bertelsen, Trine L; Mohrmann, Ralf

2014-01-01

Synchronization of neurotransmitter release with the presynaptic action potential is essential for maintaining fidelity of information transfer in the central nervous system. However, synchronous release is frequently accompanied by an asynchronous release component that builds up during repetitive...... stimulation, and can even play a dominant role in some synapses. Here, we show that substitution of SNAP-23 for SNAP-25 in mouse autaptic glutamatergic hippocampal neurons results in asynchronous release and a higher frequency of spontaneous release events (mEPSCs). Use of neurons from double-knock-out (SNAP......, while synaptotagmin-7 barely displayed activity-dependent trafficking between vesicle and plasma membrane, implying that it acts as a plasma membrane calcium sensor. Overall, these findings support the idea of alternative syt∶SNARE combinations driving release with different kinetics and fidelity....

Asynchronous emergence by loggerhead turtle (Caretta caretta) hatchlings.

Science.gov (United States)

Houghton, J D; Hays, G C

2001-03-01

For many decades it has been accepted that marine turtle hatchlings from the same nest generally emerge from the sand together. However, for loggerhead turtles (Caretta caretta) nesting on the Greek Island of Kefalonia, a more asynchronous pattern of emergence has been documented. By placing temperature loggers at the top and bottom of nests laid on Kefalonia during 1998, we examined whether this asynchronous emergence was related to the thermal conditions within nests. Pronounced thermal variation existed not only between, but also within, individual nests. These within-nest temperature differences were related to the patterns of hatchling emergence, with hatchlings from nests displaying large thermal ranges emerging over a longer time-scale than those characterised by more uniform temperatures. In many egg-laying animals, parental care of the offspring may continue while the eggs are incubating and also after they have hatched. Consequently, the importance of the nest site for determining incubation conditions may be reduced since the parents themselves may alter the local environment. By contrast, in marine turtles, parental care ceases once the eggs have been laid and the nest site covered. The positioning of the nest site, in both space and time, may therefore have profound effects for marine turtles by affecting, for example, the survival of the eggs and hatchlings as well as their sex (Janzen and Paukstis 1991). During incubation, sea turtle embryos grow from a few cells at oviposition to a self-sufficient organism at hatching some 50-80 days later (Ackerman 1997). After hatching, the young turtles dig up through the sand and emerge typically en masse at the surface 1-7 nights later, with a number of stragglers following over the next few nights (Christens 1990). This contrasts with the frequently observed pattern of hatching asynchrony in birds. It has been suggested that the cause of mass emergence in turtles is that eggs within a clutch are fertilised

Exponential Lower Bounds for the PPSZ k-SAT Algorithm

DEFF Research Database (Denmark)

Chen, Shiteng; Scheder, Dominik Alban; Talebanfard, Navid

2013-01-01

In 1998, Paturi, Pudl´ak, Saks, and Zane presented PPSZ, an elegant randomized algorithm for k-SAT. Fourteen years on, this algorithm is still the fastest known worst-case algorithm. They proved that its expected running time on k-CNF formulas with n variables is at most 2(1−k)n, where k 2 (1/k).......). So far, no exponential lower bounds at all have been known. In this paper, we construct hard instances for PPSZ. That is, we construct satisfiable k-CNF formulas over n variables on which the expected running time is at least 2(1−k)n, for k 2 O(log2 k/k)....

Energies and bounds from perturbative approximations to the Bloch-Horowitz effective Hamiltonian

International Nuclear Information System (INIS)

Darema-Rogers, F.; Vincent, C.M.

1978-01-01

Bloch-Horowitz perturbation theory is applied to the calculation of approximate energies and model-space eigenvectors, for the solvable large-matrix Hamiltonian H used by Pittel, Vincent, and Vergados. Two types of upper and lower bounds to the energies are discussed: moment-theory bounds, obtained by applying moment theory to the terms of perturbation theory, and norm bounds, derived from the expectation E-bar and variance sigma 2 of H with respect to an eigenvector approximated by nth order perturbation theory (n < or = 6). It is shown that lower bounds cannot be constructed unless some fourth-order quantity is known. The upper bounds are generally stricter than the lower bounds. All of the bounds apply even when back-door intruder states cause perturbation theory to diverge; but they lose their rigor and become ''quasibounds'' when there are physical intruders. The moment-theory and norm lower quasibounds always require estimation of a parameter. For the solvable Hamiltonians, it is shown that this can be done quite reliably, and that the resulting quasibounds are tight enough to have some practical utility. The energy-independent effective interaction V is constructed and its errors are displayed and discussed. Finally, a certain [1/2] pseudo-Pade approximant is empirically shown to give energies with a mean absolute error of less than 0.3 MeV in all cases

Asynchronous discrete event schemes for PDEs

Science.gov (United States)

Stone, D.; Geiger, S.; Lord, G. J.

2017-08-01

A new class of asynchronous discrete-event simulation schemes for advection-diffusion-reaction equations is introduced, based on the principle of allowing quanta of mass to pass through faces of a (regular, structured) Cartesian finite volume grid. The timescales of these events are linked to the flux on the face. The resulting schemes are self-adaptive, and local in both time and space. Experiments are performed on realistic physical systems related to porous media flow applications, including a large 3D advection diffusion equation and advection diffusion reaction systems. The results are compared to highly accurate reference solutions where the temporal evolution is computed with exponential integrator schemes using the same finite volume discretisation. This allows a reliable estimation of the solution error. Our results indicate a first order convergence of the error as a control parameter is decreased, and we outline a framework for analysis.

Information flow vs. resource access in the asynchronous pi-calculus

OpenAIRE

Hennessy, Matthew; Riely, James

2002-01-01

We propose an extension of the asynchronous π-calculus in which a variety of security properties may be captured using types. These are an extension of the input/output types for the π-calculus in which I/O capabilities are assigned specific security levels. The main innovation is a uniform typing system that, by varying slightly the allowed set of types, captures different notions of security.We first define a typing system that ensures that processes running at security level σ cannot acces...

Asynchronous anti-noise hyper chaotic secure communication system based on dynamic delay and state variables switching

Energy Technology Data Exchange (ETDEWEB)

Liu, Hongjun [Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, Dalian 116024 (China); Weifang Vocational College, Weifang 261041 (China); Wang, Xingyuan, E-mail: wangxy@dlut.edu.cn [Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, Dalian 116024 (China); Zhu, Quanlong [Faculty of Electronic Information and Electrical Engineering, Dalian University of Technology, Dalian 116024 (China)

2011-07-18

This Letter designs an asynchronous hyper chaotic secure communication system, which possesses high stability against noise, using dynamic delay and state variables switching to ensure the high security. The relationship between the bit error ratio (BER) and the signal-to-noise ratio (SNR) is analyzed by simulation tests, the results show that the BER can be ensured to reach zero by proportionally adjusting the amplitudes of the state variables and the noise figure. The modules of the transmitter and receiver are implemented, and numerical simulations demonstrate the effectiveness of the system. -- Highlights: → Asynchronous anti-noise hyper chaotic secure communication system. → Dynamic delay and state switching to ensure the high security. → BER can reach zero by adjusting the amplitudes of state variables and noise figure.

The Effect of Synchronous and Asynchronous Participation on Students' Performance in Online Accounting Courses

Science.gov (United States)

Duncan, Keith; Kenworthy, Amy; McNamara, Ray

2012-01-01

This article examines the relationship between MBA students' performance and participation in two online environments: a synchronous forum (chat room) and an asynchronous forum (discussion board) at an Australian university. The "quality" and "quantity" of students' participation is used to predict their final examination and…

The Role of Beliefs and Motivation in Asynchronous Online Learning in College-Level Classes

Science.gov (United States)

Xie, Kui; Huang, Kun

2014-01-01

Epistemic and learning beliefs were found to affect college students' cognitive engagement and study strategies, as well as motivation in classroom settings. However, the relationships between epistemic and learning beliefs, motivation, learning perception, and students' actual learning participation in asynchronous online settings have been…

A BMI-based occupational therapy assist suit: asynchronous control by SSVEP.

Science.gov (United States)

Sakurada, Takeshi; Kawase, Toshihiro; Takano, Kouji; Komatsu, Tomoaki; Kansaku, Kenji

2013-01-01

A brain-machine interface (BMI) is an interface technology that uses neurophysiological signals from the brain to control external machines. Recent invasive BMI technologies have succeeded in the asynchronous control of robot arms for a useful series of actions, such as reaching and grasping. In this study, we developed non-invasive BMI technologies aiming to make such useful movements using the subject's own hands by preparing a BMI-based occupational therapy assist suit (BOTAS). We prepared a pre-recorded series of useful actions-a grasping-a-ball movement and a carrying-the-ball movement-and added asynchronous control using steady-state visual evoked potential (SSVEP) signals. A SSVEP signal was used to trigger the grasping-a-ball movement and another SSVEP signal was used to trigger the carrying-the-ball movement. A support vector machine was used to classify EEG signals recorded from the visual cortex (Oz) in real time. Untrained, able-bodied participants (n = 12) operated the system successfully. Classification accuracy and time required for SSVEP detection were ~88% and 3 s, respectively. We further recruited three patients with upper cervical spinal cord injuries (SCIs); they also succeeded in operating the system without training. These data suggest that our BOTAS system is potentially useful in terms of rehabilitation of patients with upper limb disabilities.

Synthesis and Layout of an Asynchronous Network-on-Chip using Standard EDA Tools

DEFF Research Database (Denmark)

Müller, Christoph; Kasapaki, Evangelia; Sørensen, Rasmus Bo

2014-01-01

is the key role that clock signals play in specifying time-constraints for the synthesis. In this paper explain how we handled the synthesis and layout of an asynchronous network-on-chip for a multi-core platform. Focus is on the design process while the actual NOC-design and its performance are presented...

A Study of Synchronous versus Asynchronous Collaboration in an Online Business Writing Class

Science.gov (United States)

Mabrito, Mark

2006-01-01

A case study examined the collaborative experiences of students in an online business writing classroom. The purpose was to examine the same groups of students working on collaborative writing assignments in both a synchronous (real-time) and an asynchronous (non-real-time) discussion forum. This study focused on examining the amount, pattern, and…

Modifying Dialogical Strategy in Asynchronous Critical Discussions for Cross-Strait Chinese Learners

Directory of Open Access Journals (Sweden)

Jean Yiching Chiu

2014-09-01

Full Text Available In this global era, critical thinking has become crucial for educators and learners. The purpose of this research was to explore how modifying a dialogical strategy in asynchronous online discussion forums impacted Chinese learners’ critical thinking. Due to the Chinese cultural impact of social harmony, the majority of learners tend to maintain silent and avoid critical discussions in instructional settings. The author deployed an affectively supportive model in a modified dialogical strategy to structure Chinese EFL learners’ asynchronous critical postings by probing and questioning while requiring labeling of each cross-referencing posting as Agree/Disagree/Challenge/New Perspective. The participants were two cohorts of similar cultural background but under different political systems in China and Taiwan, here engaged together in cultural interactions. This study employed two research methods: standardized critical thinking tests, and focus groups. Findings reveal that learners in both cohorts indicated some improvement in their critical thinking skills. Nevertheless, there remain affective and cultural issues. Future studies are thus recommended to further investigate the potential of an adaptive model to engage critical discussions with English native speakers and optimize critical thinking for Chinese learners in an EFL environment.

Breaking The Millisecond Barrier On SpiNNaker: Implementing Asynchronous Event-Based Plastic Models With Microsecond Resolution

Directory of Open Access Journals (Sweden)

Xavier eLagorce

2015-06-01

Full Text Available Spike-based neuromorphic sensors such as retinas and cochleas, change the way in which the world is sampled. Instead of producing data sampled at a constant rate, these sensors output spikes that are asynchronous and event driven. The event-based nature of neuromorphic sensors implies a complete paradigm shift in current perception algorithms towards those that emphasize the importance of precise timing. The spikes produced by these sensors usually have a time resolution in the order of microseconds. This high temporal resolution is a crucial factor in learning tasks. It is also widely used in the field of biological neural networks. Sound localization for instance relies on detecting time lags between the two ears which, in the barn owl, reaches a temporal resolution of 5 microseconds. Current available neuromorphic computation platforms such as SpiNNaker often limit their users to a time resolution in the order of milliseconds that is not compatible with the asynchronous outputs of neuromorphic sensors. To overcome these limitations and allow for the exploration of new types of neuromorphic computing architectures, we introduce a novel software framework on the SpiNNaker platform. This framework allows for simulations of spiking networks and plasticity mechanisms using a completely asynchronous and event-based scheme running with a microsecond time resolution. Results on two example networks using this new implementation are presented.

Virial Expansion Bounds

Science.gov (United States)

Tate, Stephen James

2013-10-01

In the 1960s, the technique of using cluster expansion bounds in order to achieve bounds on the virial expansion was developed by Lebowitz and Penrose (J. Math. Phys. 5:841, 1964) and Ruelle (Statistical Mechanics: Rigorous Results. Benjamin, Elmsford, 1969). This technique is generalised to more recent cluster expansion bounds by Poghosyan and Ueltschi (J. Math. Phys. 50:053509, 2009), which are related to the work of Procacci (J. Stat. Phys. 129:171, 2007) and the tree-graph identity, detailed by Brydges (Phénomènes Critiques, Systèmes Aléatoires, Théories de Jauge. Les Houches 1984, pp. 129-183, 1986). The bounds achieved by Lebowitz and Penrose can also be sharpened by doing the actual optimisation and achieving expressions in terms of the Lambert W-function. The different bound from the cluster expansion shows some improvements for bounds on the convergence of the virial expansion in the case of positive potentials, which are allowed to have a hard core.

A 0.8mW 250MS/s time-interleaved asynchronous digital slope ADC

NARCIS (Netherlands)

Harpe, P.J.A.; Zhou, C.; Philips, K.J.P.; Groot, de H.W.H.

2010-01-01

Slope and digital-ramp converters are normally limited to very low sampling rates, since they require a digital counter at a highly oversampled clock rate. In this work, an asynchronous digital slope architecture is introduced that only requires a non-oversampled clock, thus enabling a much higher

INFLUENCE OF THE TIME OF DISINHIBITION TO TRANSIENTS AND WEAR OF THE FRICTION LININGS IN AN ASYNCHRONOUS MOTOR

Directory of Open Access Journals (Sweden)

V. V. Solencov

2016-01-01

Full Text Available Time and the stopping distance of the electric drive with frequent starting-and-braking modes that contain embedded asynchronous motor with a recessed combined braking device depend on the moment of an electromagnet disinhibition. At the same time other important criteria are taken into the account, i.e. wear resistance of the brake device and the smoothness of the deceleration of the electric drive. In general such an asynchronous motor contains asynchronous engine with squirrel-cage rotor, electromechanical normally-closed brake, electromagnetical slip clutch and control circuit. The mechanical characteristics of the deceleration of asynchronous motor with recessed combined brake device at different moments of an electromagnet disinhibition are presented. The mathematical model is featured and the transients in such a motor are presented. Formation models for computer research were carried out in the Fortran 2008 programming language. Calculation of the system of differential equations was fulfilled by the Runge – Kutta method. The deceleration of the electromechanical brake at various speeds caused different time values and stopping distances. The plots of stopping distance and the braking time at various moments of an electromagnet disinhibition are demonstrated. The optimum moment of switching on an electromechanical brake, providing small stopping distance and the braking time is the time when the speed wвкл = 0,6–0,8 of the nominal. In this case the acceptable number of brake applications for friction linings (compared with mechanical braking will increase by 1.6–2.8 times. The pilot study confirmed the validity of the obtained mathematical models and discovered patterns.

Upper bounds on superpartner masses from upper bounds on the Higgs boson mass.

Science.gov (United States)

Cabrera, M E; Casas, J A; Delgado, A

2012-01-13

The LHC is putting bounds on the Higgs boson mass. In this Letter we use those bounds to constrain the minimal supersymmetric standard model (MSSM) parameter space using the fact that, in supersymmetry, the Higgs mass is a function of the masses of sparticles, and therefore an upper bound on the Higgs mass translates into an upper bound for the masses for superpartners. We show that, although current bounds do not constrain the MSSM parameter space from above, once the Higgs mass bound improves big regions of this parameter space will be excluded, putting upper bounds on supersymmetry (SUSY) masses. On the other hand, for the case of split-SUSY we show that, for moderate or large tanβ, the present bounds on the Higgs mass imply that the common mass for scalars cannot be greater than 10(11)  GeV. We show how these bounds will evolve as LHC continues to improve the limits on the Higgs mass.

Preliminary Results on the Experimental Investigation of the Structure Functions of Bound Nucleons

Energy Technology Data Exchange (ETDEWEB)

Bodek, Arie [Univ. of Rochester, NY (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

2016-08-01

We present preliminary results on an experimental study of the nuclear modification of the longitudinal ($\\sigma_L$) and transverse ($\\sigma_T$) structure functions of nucleons bound in nuclear targets. The origin of these modifications (commonly referred as as the EMC effect) is not fully understood. Our measurements of R= $\\sigma_L / \\sigma_T$ for nuclei ($R_A$) and for deuterium ($R_D$) indicate that nuclear modifications of the structure functions of bound nucleons are different for the longitudinal and transverse structure functions, and that contrary to expectation from several theoretical models, $R_A< R_D$.

Acoustic trapping in bubble-bounded micro-cavities

Science.gov (United States)

O'Mahoney, P.; McDougall, C.; Glynne-Jones, P.; MacDonald, M. P.

2016-12-01

We present a method for controllably producing longitudinal acoustic trapping sites inside microfluidic channels. Air bubbles are injected into a micro-capillary to create bubble-bounded `micro-cavities'. A cavity mode is formed that shows controlled longitudinal acoustic trapping between the two air/water interfaces along with the levitation to the centre of the channel that one would expect from a lower order lateral mode. 7 μm and 10 μm microspheres are trapped at the discrete acoustic trapping sites in these micro-cavities.We show this for several lengths of micro-cavity.

Temperature, paternity and asynchronous hatching influence early developmental characteristics of larval Atlantic cod, Gadus morhua

DEFF Research Database (Denmark)

Politis, Sebastian Nikitas; Dahlke, Flemming T.; Butts, Ian A.E.

2014-01-01

Offspring, especially during early development, are influenced by both intrinsic properties endowed to them by their parents, extrinsic environmental factors as well as the interplay between genes and the environment. We investigated the effects of paternity (P), temperature (T), and asynchronous...

The DMM Bound

DEFF Research Database (Denmark)

Emiris, Ioannis Z.; Mourrain, Bernard; Tsigaridas, Elias

2010-01-01

) resultant by means of mixed volume, as well as recent advances on aggregate root bounds for univariate polynomials, and are applicable to arbitrary positive dimensional systems. We improve upon Canny's gap theorem [7] by a factor of O(dn-1), where d bounds the degree of the polynomials, and n is the number...... bound on the number of steps that subdivision-based algorithms perform in order to isolate all real roots of a polynomial system. This leads to the first complexity bound of Milne's algorithm [22] in 2D....

Frog: Asynchronous Graph Processing on GPU with Hybrid Coloring Model

Energy Technology Data Exchange (ETDEWEB)

Shi, Xuanhua; Luo, Xuan; Liang, Junling; Zhao, Peng; Di, Sheng; He, Bingsheng; Jin, Hai

2018-01-01

GPUs have been increasingly used to accelerate graph processing for complicated computational problems regarding graph theory. Many parallel graph algorithms adopt the asynchronous computing model to accelerate the iterative convergence. Unfortunately, the consistent asynchronous computing requires locking or atomic operations, leading to significant penalties/overheads when implemented on GPUs. As such, coloring algorithm is adopted to separate the vertices with potential updating conflicts, guaranteeing the consistency/correctness of the parallel processing. Common coloring algorithms, however, may suffer from low parallelism because of a large number of colors generally required for processing a large-scale graph with billions of vertices. We propose a light-weight asynchronous processing framework called Frog with a preprocessing/hybrid coloring model. The fundamental idea is based on Pareto principle (or 80-20 rule) about coloring algorithms as we observed through masses of realworld graph coloring cases. We find that a majority of vertices (about 80%) are colored with only a few colors, such that they can be read and updated in a very high degree of parallelism without violating the sequential consistency. Accordingly, our solution separates the processing of the vertices based on the distribution of colors. In this work, we mainly answer three questions: (1) how to partition the vertices in a sparse graph with maximized parallelism, (2) how to process large-scale graphs that cannot fit into GPU memory, and (3) how to reduce the overhead of data transfers on PCIe while processing each partition. We conduct experiments on real-world data (Amazon, DBLP, YouTube, RoadNet-CA, WikiTalk and Twitter) to evaluate our approach and make comparisons with well-known non-preprocessed (such as Totem, Medusa, MapGraph and Gunrock) and preprocessed (Cusha) approaches, by testing four classical algorithms (BFS, PageRank, SSSP and CC). On all the tested applications and

A comparison of classroom and online asynchronous problem-based learning for students undertaking statistics training as part of a Public Health Masters degree.

Science.gov (United States)

de Jong, N; Verstegen, D M L; Tan, F E S; O'Connor, S J

2013-05-01

This case-study compared traditional, face-to-face classroom-based teaching with asynchronous online learning and teaching methods in two sets of students undertaking a problem-based learning module in the multilevel and exploratory factor analysis of longitudinal data as part of a Masters degree in Public Health at Maastricht University. Students were allocated to one of the two study variants on the basis of their enrolment status as full-time or part-time students. Full-time students (n = 11) followed the classroom-based variant and part-time students (n = 12) followed the online asynchronous variant which included video recorded lectures and a series of asynchronous online group or individual SPSS activities with synchronous tutor feedback. A validated student motivation questionnaire was administered to both groups of students at the start of the study and a second questionnaire was administered at the end of the module. This elicited data about student satisfaction with the module content, teaching and learning methods, and tutor feedback. The module coordinator and problem-based learning tutor were also interviewed about their experience of delivering the experimental online variant and asked to evaluate its success in relation to student attainment of the module's learning outcomes. Student examination results were also compared between the two groups. Asynchronous online teaching and learning methods proved to be an acceptable alternative to classroom-based teaching for both students and staff. Educational outcomes were similar for both groups, but importantly, there was no evidence that the asynchronous online delivery of module content disadvantaged part-time students in comparison to their full-time counterparts.

Student Outcomes Associated with Use of Asynchronous Online Discussion Forums in Gross Anatomy Teaching

Science.gov (United States)

Green, Rodney A.; Hughes, Diane L.

2013-01-01

Asynchronous online discussion forums are increasingly common in blended learning environments but the relationship to student learning outcomes has not been reported for anatomy teaching. Forums were monitored in two multicampus anatomy courses; an introductory first year course and a second year physiotherapy-specific course. The forums are…

Peer Moderation of Asynchronous Online Discussions: An Exploratory Study of Peer E-Moderating Behaviour

Science.gov (United States)

Ghadirian, Hajar; Ayub, Ahmad Fauzi Mohd

2017-01-01

This study explored patterns of e-moderating behaviour students performed when they were assigned as peer moderators of asynchronous online discussions in a reciprocal manner. Eighty-four students from an undergraduate blended course were observed during a 7-week-long online discussions. Using quantitative content analysis peer moderators'…

Students' Desired and Experienced Levels of Connectivity to an Asynchronous, Online, Distance Degree Program

Science.gov (United States)

Schroeder, Shawnda; Baker, Mary; Terras, Katherine; Mahar, Patti; Chiasson, Kari

2016-01-01

This study examined graduate students' desired and experienced levels of connectivity in an online, asynchronous distance degree program. Connectivity was conceptualized as the students' feelings of community and involvement, not their level of access to the Internet. Graduate students enrolled in a distance degree program were surveyed on both…

NEXAFS characterization of DNA components and molecular-orientation of surface-bound DNA oligomers

International Nuclear Information System (INIS)

Samuel, Newton T.; Lee, C.-Y.; Gamble, Lara J.; Fischer, Daniel A.; Castner, David G.

2006-01-01

Single stranded DNA oligomers (ssDNA) immobilized onto solid surfaces forms the basis for several biotechnological applications such as DNA microarrays, affinity separations, and biosensors. Surface structure of Surface-bound oligomers is expected to significantly influence their biological activity and interactions with the environment. In this study near-edge X-ray absorption fine structure spectroscopy (NEXAFS) is used to characterize the components of DNA (nucleobases, nucleotides and nucleosides) and the orientation information of surface-bound ssDNA. The K-edges of carbon, nitrogen and oxygen have spectra with features that are characteristic of the different chemical species present in the nucleobases of DNA. The effect of addition of the DNA sugar and phosphate components on the NEXAFS K-edge spectra was also investigated. The polarization-dependent nitrogen K-edge NEXAFS data show significant changes for different orientations of surface bound ssDNA. These results establish NEXAFS as a powerful technique for chemical and structural characterization of surface-bound DNA oligomers

XMPP for cloud computing in bioinformatics supporting discovery and invocation of asynchronous web services.

Science.gov (United States)

Wagener, Johannes; Spjuth, Ola; Willighagen, Egon L; Wikberg, Jarl E S

2009-09-04

Life sciences make heavily use of the web for both data provision and analysis. However, the increasing amount of available data and the diversity of analysis tools call for machine accessible interfaces in order to be effective. HTTP-based Web service technologies, like the Simple Object Access Protocol (SOAP) and REpresentational State Transfer (REST) services, are today the most common technologies for this in bioinformatics. However, these methods have severe drawbacks, including lack of discoverability, and the inability for services to send status notifications. Several complementary workarounds have been proposed, but the results are ad-hoc solutions of varying quality that can be difficult to use. We present a novel approach based on the open standard Extensible Messaging and Presence Protocol (XMPP), consisting of an extension (IO Data) to comprise discovery, asynchronous invocation, and definition of data types in the service. That XMPP cloud services are capable of asynchronous communication implies that clients do not have to poll repetitively for status, but the service sends the results back to the client upon completion. Implementations for Bioclipse and Taverna are presented, as are various XMPP cloud services in bio- and cheminformatics. XMPP with its extensions is a powerful protocol for cloud services that demonstrate several advantages over traditional HTTP-based Web services: 1) services are discoverable without the need of an external registry, 2) asynchronous invocation eliminates the need for ad-hoc solutions like polling, and 3) input and output types defined in the service allows for generation of clients on the fly without the need of an external semantics description. The many advantages over existing technologies make XMPP a highly interesting candidate for next generation online services in bioinformatics.

Introducing group-based asynchronous learning to business education : Reflections on effective course design and delivery

NARCIS (Netherlands)

Arnold, I.J.M.; Walker, R.

2004-01-01

This paper explores the contribution of virtual tools to student learning within full-time management programmes. More specifically, the paper focuses on asynchronous communication tools, considering the scope they offer for group-based collaborative learning outside the classroom. We report on the

High-quality asynchronous heralded single-photon source at telecom wavelength

International Nuclear Information System (INIS)

Fasel, Sylvain; Alibart, Olivier; Tanzilli, Sebastien; Baldi, Pascal; Beveratos, Alexios; Gisin, Nicolas; Zbinden, Hugo

2004-01-01

We report on the experimental realization and characterization of an asynchronous heralded single-photon source based on spontaneous parametric down-conversion. Photons at 1550 nm are heralded as being inside a single-mode fibre with more than 60% probability, and the multi-photon emission probability is reduced by a factor of up to more than 500 compared to Poissonian light sources. These figures of merit, together with the choice of telecom wavelength for the heralded photons, are compatible with practical applications needing very efficient and robust single-photon sources

A Reward-Maximizing Spiking Neuron as a Bounded Rational Decision Maker.

Science.gov (United States)

Leibfried, Felix; Braun, Daniel A

2015-08-01

Rate distortion theory describes how to communicate relevant information most efficiently over a channel with limited capacity. One of the many applications of rate distortion theory is bounded rational decision making, where decision makers are modeled as information channels that transform sensory input into motor output under the constraint that their channel capacity is limited. Such a bounded rational decision maker can be thought to optimize an objective function that trades off the decision maker's utility or cumulative reward against the information processing cost measured by the mutual information between sensory input and motor output. In this study, we interpret a spiking neuron as a bounded rational decision maker that aims to maximize its expected reward under the computational constraint that the mutual information between the neuron's input and output is upper bounded. This abstract computational constraint translates into a penalization of the deviation between the neuron's instantaneous and average firing behavior. We derive a synaptic weight update rule for such a rate distortion optimizing neuron and show in simulations that the neuron efficiently extracts reward-relevant information from the input by trading off its synaptic strengths against the collected reward.

Comparing Face-To-Face and Asynchronous Online Communication as Mechanisms for Critical Reflective Dialogue

Science.gov (United States)

Salter, Susan; Douglas, Tracy; Kember, David

2017-01-01

Two mechanisms for engaging in critical reflective dialogue are discussed and compared: face-to-face meetings and asynchronous online discussion. The context is an umbrella action research project, with over 20 participants, which aimed to improve practices in online teaching and contribute to the development of graduate attributes. The article…

Toward Personal and Emotional Connectivity in Mobile Higher Education through Asynchronous Formative Audio Feedback

Science.gov (United States)

Rasi, Päivi; Vuojärvi, Hanna

2018-01-01

This study aims to develop asynchronous formative audio feedback practices for mobile learning in higher education settings. The development was conducted in keeping with the principles of design-based research. The research activities focused on an inter-university online course, within which the use of instructor audio feedback was tested,…

A Comparison of Asynchronous Online Text-Based Lectures and Synchronous Interactive Web Conferencing Lectures

Science.gov (United States)

Skylar, Ashley Ann

2009-01-01

Online learning environments are more prevalent in teacher education than ever before. In 2009, many instructors are attempting to emulate traditional instructional methods in the online learning environment as much as possible. Online courses are separated into two categories, (1) asynchronous; and (2) synchronous, depending on the nature of the…

Asynchronous Knowledge Sharing and Conversation Interaction Impact on Grade in an Online Business Course

Science.gov (United States)

Strang, Kenneth David

2011-01-01

Student knowledge sharing and conversation theory interactions were coded from asynchronous discussion forums to measure the effect of learning-oriented utterances on academic performance. The sample was 3 terms of an online business course (in an accredited MBA program) at a U.S.-based university. Correlation, stepwise regression, and multiple…

Induction motor for superconducting synchronous/asynchronous motor

International Nuclear Information System (INIS)

Litz, D.C.; Haller, H.E. III.

1975-01-01

An induction motor structure for use on the outside of a superconducting rotor comprising a cylindrical shell of solid and laminated, magnetic iron with squirrel cage windings embedded in the outer circumference of said shell is described. The sections of the shell between the superconducting windings of the rotor are solid magnetic iron. The sections of the shell over the superconducting windings are made of laminations of magnetic iron. These laminations are parallel to the axis of the machine and are divided in halves with the laminations in each half oriented in diagonal opposition so that the intersection of the laminations forms a V. This structure presents a relatively high reluctance to leakage flux from the superconducting windings in the synchronous operating mode, while presenting a low reluctance path to the stator flux during asynchronous operation

Organically bound tritium

International Nuclear Information System (INIS)

Diabate, S.; Strack, S.

1993-01-01

Tritium released into the environment may be incorporated into organic matter. Organically bound tritium in that case will show retention times in organisms that are considerably longer than those of tritiated water which has significant consequences on dose estimates. This article reviews the most important processes of organically bound tritium production and transport through food networks. Metabolic reactions in plant and animal organisms with tritiated water as a reaction partner are of great importance in this respect. The most important production process, in quantitative terms, is photosynthesis in green plants. The translocation of organically bound tritium from the leaves to edible parts of crop plants should be considered in models of organically bound tritium behavior. Organically bound tritium enters the human body on several pathways, either from the primary producers (vegetable food) or at a higher tropic level (animal food). Animal experiments have shown that the dose due to ingestion of organically bound tritium can be up to twice as high as a comparable intake of tritiated water in gaseous or liquid form. In the environment, organically bound tritium in plants and animals is often found to have higher specific tritium concentrations than tissue water. This is not due to some tritium enrichment effects but to the fact that no equilibrium conditions are reached under natural conditions. 66 refs

Is multiple sclerosis a length-dependent central axonopathy? The case for therapeutic lag and the asynchronous progressive MS hypotheses.

Science.gov (United States)

Giovannoni, Gavin; Cutter, Gary; Sormani, Maria Pia; Belachew, Shibeshih; Hyde, Robert; Koendgen, Harold; Knappertz, Volker; Tomic, Davorka; Leppert, David; Herndon, Robert; Wheeler-Kingshott, Claudia A M; Ciccarelli, Olga; Selwood, David; di Cantogno, Elisabetta Verdun; Ben-Amor, Ali-Frederic; Matthews, Paul; Carassiti, Daniele; Baker, David; Schmierer, Klaus

2017-02-01

Trials of anti-inflammatory therapies in non-relapsing progressive multiple sclerosis (MS) have been stubbornly negative except recently for an anti-CD20 therapy in primary progressive MS and a S1P modulator siponimod in secondary progressive MS. We argue that this might be because trials have been too short and have focused on assessing neuronal pathways, with insufficient reserve capacity, as the core component of the primary outcome. Delayed neuroaxonal degeneration primed by prior inflammation is not expected to respond to disease-modifying therapies targeting MS-specific mechanisms. However, anti-inflammatory therapies may modify these damaged pathways, but with a therapeutic lag that may take years to manifest. Based on these observations we propose that clinically apparent neurodegenerative components of progressive MS may occur in a length-dependent manner and asynchronously. If this hypothesis is confirmed it may have major implications for the future design of progressive MS trials. Copyright © 2016 Elsevier B.V. All rights reserved.

Conditions for Model Matching of Switched Asynchronous Sequential Machines with Output Feedback

OpenAIRE

Jung–Min Yang

2016-01-01

Solvability of the model matching problem for input/output switched asynchronous sequential machines is discussed in this paper. The control objective is to determine the existence condition and design algorithm for a corrective controller that can match the stable-state behavior of the closed-loop system to that of a reference model. Switching operations and correction procedures are incorporated using output feedback so that the controlled switched machine can show the ...

Determining sociability, social space, and social presence in (A)synchronous collaborative groups

OpenAIRE

Kreijns, K.; Kirschner, P.A.; Jochems, W.; Buuren, H. van

2004-01-01

The effectiveness of group learning in asynchronous distributed learning groups depends on the social interaction that takes place. This social interaction affects both cognitive and socioemotional processes that take place during learning, group forming, establishment of group structures, and group dynamics. Though now known to be important, this aspect is often ignored, denied or forgotten by educators and researchers who tend to concentrate on cognitive processes and on-task contexts. This...

Physical Uncertainty Bounds (PUB)

Energy Technology Data Exchange (ETDEWEB)

Vaughan, Diane Elizabeth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Preston, Dean L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2015-03-19

This paper introduces and motivates the need for a new methodology for determining upper bounds on the uncertainties in simulations of engineered systems due to limited fidelity in the composite continuum-level physics models needed to simulate the systems. We show that traditional uncertainty quantification methods provide, at best, a lower bound on this uncertainty. We propose to obtain bounds on the simulation uncertainties by first determining bounds on the physical quantities or processes relevant to system performance. By bounding these physics processes, as opposed to carrying out statistical analyses of the parameter sets of specific physics models or simply switching out the available physics models, one can obtain upper bounds on the uncertainties in simulated quantities of interest.

A BMI-based occupational therapy assist suit: asynchronous control by SSVEP

Directory of Open Access Journals (Sweden)

Takeshi eSakurada

2013-09-01

Full Text Available A brain-machine interface (BMI is an interface technology that uses neurophysiological signals from the brain to control external machines. Recent invasive BMI technologies have succeeded in the asynchronous control of robot arms for a useful series of actions, such as reaching and grasping. In this study, we developed non-invasive BMI technologies aiming to make such useful movements using the subject's own hands by preparing a BMI-based occupational therapy assist suit (BOTAS. We prepared a pre-recorded series of useful actionsa grasping-a-ball movement and a carrying-the-ball movementand added asynchronous control using steady-state visual evoked potential (SSVEP signals. A SSVEP signal was used to trigger the grasping-a-ball movement and another SSVEP signal was used to trigger the carrying-the-ball movement. A support vector machine was used to classify EEG signals recorded from the visual cortex (Oz in real time. Untrained, able-bodied participants (n = 12 operated the system successfully. Classification accuracy and time required for SSVEP detection were approximately 88% and 3 s, respectively. We further recruited three patients with upper cervical spinal cord injuries; they also succeeded in operating the system without training. These data suggest that our BOTAS system is potentially useful in terms of rehabilitation of patients with upper limb disabilities.

Hand-Rim Forces and Gross Mechanical Efficiency in Asynchronous and Synchronous Wheelchair Propulsion : A Comparison

NARCIS (Netherlands)

Lenton, J. P.; Fowler, N.; Nicholson, G.; Tolfrey, K.; Goosey-Tolfrey, V.; van der Woude, Lucas

To compare the force application characteristics at various push frequencies of asynchronous (ASY) and synchronous (SYN) hand-rim propulsion, 8 able-bodied participants performed a separate sub-maximal exercise test on a wheelchair roller ergometer for each propulsion mode. Each test consisted of a

Solvent effect on the degree of (a)synchronicity in polar Diels-Alder reactions from the perspective of the reaction force constant analysis.

Science.gov (United States)

Yepes, Diana; Martínez-Araya, Jorge I; Jaque, Pablo

2017-12-29

In this work, we computationally evaluated the influence of six different molecular solvents, described as a polarizable continuum model at the M06-2X/6-31+G(d,p) level, on the activation barrier/reaction rate, overall energy change, TS geometry, and degree of (a)synchronicity of two concerted Diels-Alder cycloadditions of acrolein (R1) and its complex with Lewis acid acrolein···BH 3 (R2) to cyclopentadiene. In gas-phase, we found that both exothermicity and activation barrier are only reduced by about 2.0 kcal mol -1 , and the asynchronicity character of the mechanism is accentuated when BH 3 is included. An increment in the solvent's polarity lowers the activation energy of R1 by 1.3 kcal mol -1 , while for R2 the reaction rate is enhanced by more than 2000 times at room temperature (i.e., the activation energy decreases by 4.5 kcal mol -1 ) if the highest polar media is employed. Therefore, a synergistic effect is achieved when both external agents, i.e., Lewis acid catalyst and polar solvent, are included together. This effect was ascribed to the ability of the solvent to favor the encounter between cyclopentadiene and acrolein···BH 3 . This was validated by the asymmetry of the TS which becomes highly pronounced when either both or just BH 3 is considered or the solvent's polarity is increased. Finally, the reaction force constant κ(ξ) reveals that an increment in the solvent's polarity is able to turn a moderate asynchronous mechanism of the formation of the new C-C σ-bonds into a highly asynchronous one. Graphical abstract A synergistic effect is achieved when both external agents, i.e., Lewis acid catalyst and polar solvent, are included together: lowered energy barriers and increased asynchronicities.

Learner Perceptions of Asynchronous Oral Computer-mediated Communication: Proficiency and Second Langauge Selves

Directory of Open Access Journals (Sweden)

Jesse Gleason

2012-06-01

Full Text Available Abstract The present study addresses the perceptions of international teaching assistants regarding the role of language learning tasks using Wimba Voice (WV in aiding the improvement of their second language (L2 oral skills. It specifically examines how this asynchronous computer-mediated communication (CMC technology can foster the development of these learners’ L2 selves. According to Dörnyei (2009, the more clearly learners can envision their future L2 selves, the more motivated they will be to achieve their L2 goals. With increased planning of oral production, access to instructor and peer feedback, and additional opportunities for self-reflection, asynchronous CMC technologies have been found to enable L2 learners to express their thoughts at their own pace and feel more relaxed and confident than in more threatening face-to-face situations (Sun, 2009. The findings suggest that learners have a variety of opinions regarding the role of asynchronous WV tasks in motivating them to develop their L2 oral proficiency. Also, many may prefer oral CMC environments that facilitate interaction and meaning negotiation. Results were inconclusive concerning the effect of WV-based tasks on students' perceptions of their future L2 selves; however, this may have been due to the short time frame in which these activities were employed. Résumé Nous étudions ici les perceptions d’un groupe d’assistants internationaux sur le rôle des tâches d’apprentissage linguistique à l’aide de Wimba Voice (WV. Le projet avait pour but d’améliorer les compétences orales des participants dans leur langue seconde. La présente étude examine en particulier la voie par laquelle cette technologie de la communication asynchrone par ordinateur peut favoriser l’évolution de la langue seconde des apprenants. Selon Dörnyei (2009, plus les apprenants peuvent envisager clairement un futur emploi de leur langue seconde, plus ils seront motivés à atteindre

Asynchronous sampled-data approach for event-triggered systems

Science.gov (United States)

Mahmoud, Magdi S.; Memon, Azhar M.

2017-11-01

While aperiodically triggered network control systems save a considerable amount of communication bandwidth, they also pose challenges such as coupling between control and event-condition design, optimisation of the available resources such as control, communication and computation power, and time-delays due to computation and communication network. With this motivation, the paper presents separate designs of control and event-triggering mechanism, thus simplifying the overall analysis, asynchronous linear quadratic Gaussian controller which tackles delays and aperiodic nature of transmissions, and a novel event mechanism which compares the cost of the aperiodic system against a reference periodic implementation. The proposed scheme is simulated on a linearised wind turbine model for pitch angle control and the results show significant improvement against the periodic counterpart.

Operational aspects of asynchronous filtering for flood forecasting

Science.gov (United States)

Rakovec, O.; Weerts, A. H.; Sumihar, J.; Uijlenhoet, R.

2015-06-01

This study investigates the suitability of the asynchronous ensemble Kalman filter (AEnKF) and a partitioned updating scheme for hydrological forecasting. The AEnKF requires forward integration of the model for the analysis and enables assimilation of current and past observations simultaneously at a single analysis step. The results of discharge assimilation into a grid-based hydrological model (using a soil moisture error model) for the Upper Ourthe catchment in the Belgian Ardennes show that including past predictions and observations in the data assimilation method improves the model forecasts. Additionally, we show that elimination of the strongly non-linear relation between the soil moisture storage and assimilated discharge observations from the model update becomes beneficial for improved operational forecasting, which is evaluated using several validation measures.

Operational aspects of asynchronous filtering for hydrological forecasting

Science.gov (United States)

Rakovec, O.; Weerts, A. H.; Sumihar, J.; Uijlenhoet, R.

2015-03-01

This study investigates the suitability of the Asynchronous Ensemble Kalman Filter (AEnKF) and a partitioned updating scheme for hydrological forecasting. The AEnKF requires forward integration of the model for the analysis and enables assimilation of current and past observations simultaneously at a single analysis step. The results of discharge assimilation into a grid-based hydrological model for the Upper Ourthe catchment in the Belgian Ardennes show that including past predictions and observations in the data assimilation method improves the model forecasts. Additionally, we show that elimination of the strongly non-linear relation between the soil moisture storage and assimilated discharge observations from the model update becomes beneficial for improved operational forecasting, which is evaluated using several validation measures.

PELATIHAN PLIOMETRIK ALTERNATE LEG BOUND DAN DOUBLE LEG BOUND MENINGKATKAN DAYA LEDAK OTOT TUNGKAI PADA SISWA PUTRA KELAS VII SMP NEGERI 3 SUKAWATI TAHUN PELAJARAN 2012/2013

Directory of Open Access Journals (Sweden)

Komang Ayu Tri Widhiyanti

2013-11-01

Full Text Available This study was conducted to know the improvement the explosive power of leg muscle. It was done through 5 set 12 repetitions during 6 weeks in the field of SMP Negeri 3 Sukawati started from 4 p.m. until 6 p.m. There were 3 groups applied in this study such as group 1 (control group that was instructed to kick a ball, group 2 (plyometric training of alternate leg bound, and group 3 (plyometric training of double leg bound. The sample was 14 male students who were in the seventh grade class of SMP Negeri 3 Sukawati in the academic year 2012/2013. The data was gained by doing the movement of alternate leg bound and double leg bound that each movement was done three times before and after the training. The hypothesis was examined by using independent t-test with the result 0.05 (p<0.05. Based on the different result of analysis test in each group, the gain score of the group 2 with the group 1 about 0,51 that shows the significant differences p = 0,00, the gain score of the group 2 with the group 3 about 0,31 that shows the significant differences p = 0,00, the gain score of the group 3 with the group 1 about 0,20 that shows the significant differences p = 0,00. Thus, alternate leg bound plyometric training is more effective than double leg bound. It is expected that the coach and the gym teacher to apply alternate leg bound plyometric training as an alternative to improve the explosive power of leg muscle.

Effects of Asynchronous Music on Students' Lesson Satisfaction and Motivation at the Situational Level

Science.gov (United States)

Digelidis, Nikolaos; Karageorghis, Costas I.; Papapavlou, Anastasia; Papaioannou, Athanasios G.

2014-01-01

The aim of this study was to examine the effects of asynchronous (background) music on senior students' motivation and lesson satisfaction at the situational level. A counterbalanced mixed-model design was employed with two factors comprising condition (three levels) and gender (two levels). Two hundred students (82 boys, 118 girls; M [subscript…

Investigation on intermolecular interaction between berberine and β-cyclodextrin by 2D UV-Vis asynchronous spectra.

Science.gov (United States)

He, Anqi; Kang, Xiaoyan; Xu, Yizhuang; Noda, Isao; Ozaki, Yukihiro; Wu, Jinguang

2017-10-05

The interaction between berberine chloride and β-cyclodextrin (β-CyD) is investigated via 2D asynchronous UV-Vis spectrum. The occurrence of cross peaks around (420nm, 420nm) in 2D asynchronous spectrum reveals that specific intermolecular interaction indeed exists between berberine chloride and β-CyD. In spite of the difficulty caused by overlapping of cross peaks, we manage to confirm that the 420nm band of berberine undergoes a red-shift, and its bandwidth decreases under the interaction with β-CyD. The red-shift of the 420nm band that can be assigned to n-π* transition indicates the environment of berberine becomes more hydrophobic. The above spectral behavior is helpful in understanding why the solubility of berberine is enhanced by β-CyD. Copyright © 2017. Published by Elsevier B.V.

A method to derive fixed budget results from expected optimisation times

DEFF Research Database (Denmark)

Doerr, Benjamin; Jansen, Thomas; Witt, Carsten

2013-01-01

At last year's GECCO a novel perspective for theoretical performance analysis of evolutionary algorithms and other randomised search heuristics was introduced that concentrates on the expected function value after a pre-defined number of steps, called budget. This is significantly different from...... the common perspective where the expected optimisation time is analysed. While there is a huge body of work and a large collection of tools for the analysis of the expected optimisation time the new fixed budget perspective introduces new analytical challenges. Here it is shown how results on the expected...... optimisation time that are strengthened by deviation bounds can be systematically turned into fixed budget results. We demonstrate our approach by considering the (1+1) EA on LeadingOnes and significantly improving previous results. We prove that deviating from the expected time by an additive term of ω(n3...

Study on the Implications of Asynchronous GMO Approvals for EU Imports of Animal Feed Products

NARCIS (Netherlands)

Nowicki, P.L.; Aramyan, L.H.; Baltussen, W.H.M.; Dvortsin, L.; Jongeneel, R.A.; Perez Dominguez, I.; Wagenberg, van C.P.A.; Kalaitzandonakes, N.; Kaufman, J.; Miller, D.; Franke, L.; Meerbeek, B.

2010-01-01

The aim of this study is to understand the implications of asynchronous approvals for genetically modified organisms (GMOs) that are imported to the European Union for use within animal feed products, specifically with regard to the EU livestock sector, as well as upon the upstream and downstream

ANALYTICAL CALCULATION OF THE BASIC ELECTROMAGNETIC LOSSES OF THE ENERGY OF THE FREQUENCY-REGULATED ASYNCHRONOUS ENGINE IN POSITIONING

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V. O. Volkov

2018-02-01

Full Text Available Purpose. Obtaining analytical dependencies for the calculation of the main electromagnetic energy losses of a frequency-controlled induction motor in positioning modes with small displacements for various types (linear, parabolic and quasi-optimal of its velocity variation. Methodology. Similarity methods, differential and integral calculus, analytical interpolation, mathematical analysis. Findings. Analytical dependencies for calculation of current electromagnetic power losses and basic electromagnetic energy losses of a frequency-controlled asynchronous motor in the modes of positioning with small displacements for various types (linear, parabolic and quasi-optimal of its velocity are obtained. A universal form of the analytical dependence for calculating the optimal acceleration and deceleration times for a frequency-controlled asynchronous motor for positioning with small displacements, corresponding to minimization of the main electromagnetic energy losses of this engine with the indicated positioning for various species (linear, parabolic and quasi-optimal, is obtained. A comparative quantitative assessment of the change is made: the optimum values of the main electromagnetic energy losses of the frequency-controlled asynchronous engine and the corresponding maximum speed and optimal acceleration and deceleration times, in the function of the set prescribed small displacements for the various engine speed trajectories under consideration. Originality. For the first time, analytical dependencies for the calculation of the main electromagnetic energy losses of a frequency-controlled asynchronous motor are obtained for positioning with small displacements as a function of the set values of the movement of the motor shaft and the set values of its acceleration and deceleration times for the specified specified displacements. For the first time, dependences are obtained for a quantitative estimate of the minimum fundamental electromagnetic

Operational aspects of asynchronous filtering for improved flood forecasting

Science.gov (United States)

Rakovec, Oldrich; Weerts, Albrecht; Sumihar, Julius; Uijlenhoet, Remko

2014-05-01

Hydrological forecasts can be made more reliable and less uncertain by recursively improving initial conditions. A common way of improving the initial conditions is to make use of data assimilation (DA), a feedback mechanism or update methodology which merges model estimates with available real world observations. The traditional implementation of the Ensemble Kalman Filter (EnKF; e.g. Evensen, 2009) is synchronous, commonly named a three dimensional (3-D) assimilation, which means that all assimilated observations correspond to the time of update. Asynchronous DA, also called four dimensional (4-D) assimilation, refers to an updating methodology, in which observations being assimilated into the model originate from times different to the time of update (Evensen, 2009; Sakov 2010). This study investigates how the capabilities of the DA procedure can be improved by applying alternative Kalman-type methods, e.g., the Asynchronous Ensemble Kalman Filter (AEnKF). The AEnKF assimilates observations with smaller computational costs than the original EnKF, which is beneficial for operational purposes. The results of discharge assimilation into a grid-based hydrological model for the Upper Ourthe catchment in Belgian Ardennes show that including past predictions and observations in the AEnKF improves the model forecasts as compared to the traditional EnKF. Additionally we show that elimination of the strongly non-linear relation between the soil moisture storage and assimilated discharge observations from the model update becomes beneficial for an improved operational forecasting, which is evaluated using several validation measures. In the current study we employed the HBV-96 model built within a recently developed open source modelling environment OpenStreams (2013). The advantage of using OpenStreams (2013) is that it enables direct communication with OpenDA (2013), an open source data assimilation toolbox. OpenDA provides a number of algorithms for model calibration

XMPP for cloud computing in bioinformatics supporting discovery and invocation of asynchronous web services

Science.gov (United States)

Wagener, Johannes; Spjuth, Ola; Willighagen, Egon L; Wikberg, Jarl ES

2009-01-01

Background Life sciences make heavily use of the web for both data provision and analysis. However, the increasing amount of available data and the diversity of analysis tools call for machine accessible interfaces in order to be effective. HTTP-based Web service technologies, like the Simple Object Access Protocol (SOAP) and REpresentational State Transfer (REST) services, are today the most common technologies for this in bioinformatics. However, these methods have severe drawbacks, including lack of discoverability, and the inability for services to send status notifications. Several complementary workarounds have been proposed, but the results are ad-hoc solutions of varying quality that can be difficult to use. Results We present a novel approach based on the open standard Extensible Messaging and Presence Protocol (XMPP), consisting of an extension (IO Data) to comprise discovery, asynchronous invocation, and definition of data types in the service. That XMPP cloud services are capable of asynchronous communication implies that clients do not have to poll repetitively for status, but the service sends the results back to the client upon completion. Implementations for Bioclipse and Taverna are presented, as are various XMPP cloud services in bio- and cheminformatics. Conclusion XMPP with its extensions is a powerful protocol for cloud services that demonstrate several advantages over traditional HTTP-based Web services: 1) services are discoverable without the need of an external registry, 2) asynchronous invocation eliminates the need for ad-hoc solutions like polling, and 3) input and output types defined in the service allows for generation of clients on the fly without the need of an external semantics description. The many advantages over existing technologies make XMPP a highly interesting candidate for next generation online services in bioinformatics. PMID:19732427

XMPP for cloud computing in bioinformatics supporting discovery and invocation of asynchronous web services

Directory of Open Access Journals (Sweden)

Willighagen Egon L

2009-09-01

Full Text Available Abstract Background Life sciences make heavily use of the web for both data provision and analysis. However, the increasing amount of available data and the diversity of analysis tools call for machine accessible interfaces in order to be effective. HTTP-based Web service technologies, like the Simple Object Access Protocol (SOAP and REpresentational State Transfer (REST services, are today the most common technologies for this in bioinformatics. However, these methods have severe drawbacks, including lack of discoverability, and the inability for services to send status notifications. Several complementary workarounds have been proposed, but the results are ad-hoc solutions of varying quality that can be difficult to use. Results We present a novel approach based on the open standard Extensible Messaging and Presence Protocol (XMPP, consisting of an extension (IO Data to comprise discovery, asynchronous invocation, and definition of data types in the service. That XMPP cloud services are capable of asynchronous communication implies that clients do not have to poll repetitively for status, but the service sends the results back to the client upon completion. Implementations for Bioclipse and Taverna are presented, as are various XMPP cloud services in bio- and cheminformatics. Conclusion XMPP with its extensions is a powerful protocol for cloud services that demonstrate several advantages over traditional HTTP-based Web services: 1 services are discoverable without the need of an external registry, 2 asynchronous invocation eliminates the need for ad-hoc solutions like polling, and 3 input and output types defined in the service allows for generation of clients on the fly without the need of an external semantics description. The many advantages over existing technologies make XMPP a highly interesting candidate for next generation online services in bioinformatics.

Asynchronous detection of kinesthetic attention during mobilization of lower limbs using EEG measurements

Science.gov (United States)

Melinscak, Filip; Montesano, Luis; Minguez, Javier

2016-02-01

Objective. Attention is known to modulate the plasticity of the motor cortex, and plasticity is crucial for recovery in motor rehabilitation. This study addresses the possibility of using an EEG-based brain-computer interface (BCI) to detect kinesthetic attention to movement. Approach. A novel experiment emulating physical rehabilitation was designed to study kinesthetic attention. The protocol involved continuous mobilization of lower limbs during which participants reported levels of attention to movement—from focused kinesthetic attention to mind wandering. For this protocol an asynchronous BCI detector of kinesthetic attention and deliberate mind wandering was designed. Main results. EEG analysis showed significant differences in theta, alpha, and beta bands, related to the attentional state. These changes were further pinpointed to bands relative to the frequency of the individual alpha peak. The accuracy of the designed BCI ranged between 60.8% and 68.4% (significantly above chance level), depending on the used analysis window length, i.e. acceptable detection delay. Significance. This study shows it is possible to use self-reporting to study attention-related changes in EEG during continuous mobilization. Such a protocol is used to develop an asynchronous BCI detector of kinesthetic attention, with potential applications to motor rehabilitation.

Asynchronous Amazon forest canopy phenology indicates adaptation to both water and light availability

International Nuclear Information System (INIS)

Jones, Matthew O; Kimball, John S; Nemani, Ramakrishna R

2014-01-01

Amazon forests represent nearly half of all tropical vegetation biomass and, through photosynthesis and respiration, annually process more than twice the amount of estimated carbon (CO 2 ) from fossil fuel emissions. Yet the seasonality of Amazon canopy cover, and the extent to which seasonal fluctuations in water availability and photosynthetically available radiation influence these processes, is still poorly understood. Implementing six remotely sensed data sets spanning nine years (2003–2011), with reported field and flux tower data, we show that southern equatorial Amazon forests exhibit a distinctive seasonal signal. Seasonal timing of water availability, canopy biomass growth and net leaf flush are asynchronous in regions with short dry seasons and become more synchronous across a west-to-east longitudinal moisture gradient of increasing dry season. Forest cover is responsive to seasonal disparities in both water and solar radiation availability, temporally adjusting net leaf flush to maximize use of these generally abundant resources, while reducing drought susceptibility. An accurate characterization of this asynchronous behavior allows for improved understanding of canopy phenology across contiguous tropical forests and their sensitivity to climate variability and drought. (letter)

Asynchronous web-based learning, a practical method to enhance teaching in emergency medicine.

Science.gov (United States)

Pourmand, Ali; Lucas, Raymond; Nouraie, Mehdi

2013-03-01

Abstract Objective: To compare medical knowledge acquisition among emergency medicine (EM) residents who attend weekly core content lectures with those absent but asynchronously viewing the same lectures in a Web-based electronic platform. During the study period all EM residents attending or absent from weekly educational conferences were given a quiz on the covered material. During Phase 1, absentees were not given supplemental educational content for missed lectures. During Phase 2, absentees were sent a link to an online multimedia module containing an audiovisual recording of the actual missed lecture with presentation slides. Scores between attendees and absentees during both phases were compared using a repeated-measures analysis to evaluate the effect of the supplemental online module on knowledge acquisition. Thirty-nine EM residents (equally distributed in postgraduate years 1-4) were studied during a 15-week period. Overall and after adjusting for sex and postgraduate year level, both lecture attendance (b=27; 95% confidence interval, 22-32; pcontent lectures. The percentage of curriculum delivery by asynchronous learning that may be used to achieve overall terminal learning objectives in medical knowledge acquisition requires further study.

Realistic modelling of the effects of asynchronous motion at the base of bridge piers

International Nuclear Information System (INIS)

Romanelli, F.; Panza, G.F.; Vaccari, F.

2002-11-01

Frequently long-span bridges provide deep valley crossings, which require special consideration due to the possibility of local amplification of the ground motion as a consequence of topographical irregularities and local soil conditions. This does in fact cause locally enhanced seismic input with the possibility for the bridge piers to respond asynchronously. This introduces special design requirements so that possible out-of-phase ground displacements and the associated large relative displacements of adjacent piers can be accommodated without excessive damage. Assessment of the local variability of the ground motion due to local lateral heterogeneities and to attenuation properties is thus crucial toward the realistic definition of the asynchronous motion at the base of the bridge piers. We illustrate the work done in the framework of a large international cooperation to assess the importance of non-synchronous seismic excitation of long structures. To accomplish this task we compute complete synthetic accelerograms using as input a set of parameters that describes, to the best of our knowledge, the geological structure and seismotectonic setting of the investigated area. (author)

The probability estimate of the defects of the asynchronous motors based on the complex method of diagnostics

Science.gov (United States)

Zhukovskiy, Yu L.; Korolev, N. A.; Babanova, I. S.; Boikov, A. V.

2017-10-01

This article is devoted to the development of a method for probability estimate of failure of an asynchronous motor as a part of electric drive with a frequency converter. The proposed method is based on a comprehensive method of diagnostics of vibration and electrical characteristics that take into account the quality of the supply network and the operating conditions. The developed diagnostic system allows to increase the accuracy and quality of diagnoses by determining the probability of failure-free operation of the electromechanical equipment, when the parameters deviate from the norm. This system uses an artificial neural networks (ANNs). The results of the system for estimator the technical condition are probability diagrams of the technical state and quantitative evaluation of the defects of the asynchronous motor and its components.

78 FR 18326 - Agency Information Collection Activities; Comment Request; Upward Bound and Upward Bound Math...

Science.gov (United States)

2013-03-26

...; Comment Request; Upward Bound and Upward Bound Math Science Annual Performance Report AGENCY: The Office... considered public records. Title of Collection: Upward Bound and Upward Bound Math Science Annual Performance...) and Upward Bound Math and Science (UBMS) Programs. The Department is requesting a new APR because of...

Universal bounds on current fluctuations.

Science.gov (United States)

Pietzonka, Patrick; Barato, Andre C; Seifert, Udo

2016-05-01

For current fluctuations in nonequilibrium steady states of Markovian processes, we derive four different universal bounds valid beyond the Gaussian regime. Different variants of these bounds apply to either the entropy change or any individual current, e.g., the rate of substrate consumption in a chemical reaction or the electron current in an electronic device. The bounds vary with respect to their degree of universality and tightness. A universal parabolic bound on the generating function of an arbitrary current depends solely on the average entropy production. A second, stronger bound requires knowledge both of the thermodynamic forces that drive the system and of the topology of the network of states. These two bounds are conjectures based on extensive numerics. An exponential bound that depends only on the average entropy production and the average number of transitions per time is rigorously proved. This bound has no obvious relation to the parabolic bound but it is typically tighter further away from equilibrium. An asymptotic bound that depends on the specific transition rates and becomes tight for large fluctuations is also derived. This bound allows for the prediction of the asymptotic growth of the generating function. Even though our results are restricted to networks with a finite number of states, we show that the parabolic bound is also valid for three paradigmatic examples of driven diffusive systems for which the generating function can be calculated using the additivity principle. Our bounds provide a general class of constraints for nonequilibrium systems.

Tidal Love numbers of neutron and self-bound quark stars

International Nuclear Information System (INIS)

Postnikov, Sergey; Prakash, Madappa; Lattimer, James M.

2010-01-01

Gravitational waves from the final stages of inspiraling binary neutron stars are expected to be one of the most important sources for ground-based gravitational wave detectors. The masses of the components are determinable from the orbital and chirp frequencies during the early part of the evolution, and large finite-size (tidal) effects are measurable toward the end of inspiral, but the gravitational wave signal is expected to be very complex at this time. Tidal effects during the early part of the evolution will form a very small correction, but during this phase the signal is relatively clean. The accumulated phase shift due to tidal corrections is characterized by a single quantity related to a star's tidal Love number. The Love number is sensitive, in particular, to the compactness parameter M/R and the star's internal structure, and its determination could provide an important constraint to the neutron star radius. We show that Love numbers of self-bound strange quark matter stars are qualitatively different from those of normal neutron stars. Observations of the tidal signature from coalescing compact binaries could therefore provide an important, and possibly unique, way to distinguish self-bound strange quark stars from normal neutron stars. Tidal signatures from self-bound strange quark stars with masses smaller than 1M · are substantially smaller than those of normal stars owing to their smaller radii. Thus tidal signatures of stars less massive than 1M · are probably not detectable with Advanced LIGO. For stars with masses in the range 1-2M · , the anticipated efficiency of the proposed Einstein telescope would be required for the detection of tidal signatures.

Introducing Group-Based Asynchronous Learning to Business Education. Reflections on Effective Course Design and Delivery

Science.gov (United States)

Walker, Richard; Arnold, Ivo

2004-01-01

This paper explores the contribution of virtual tools to student learning within full-time management programmes. More specifically, the paper focuses on asynchronous communication tools, considering the scope they offer for group-based collaborative learning outside the classroom. We report on the effectiveness of this approach for an economics…

An Integrated Approach to Preempt Cheating on Asynchronous, Objective, Online Assessments in Graduate Business Classes

Science.gov (United States)

Sullivan, Daniel P.

2016-01-01

Cheating, left untended, erodes the validity of evaluation and, ultimately, corrupts the legitimacy of a course. We profile an approach to manage, with an eye toward preempting, cheating on asynchronous, objective, online quizzes. This approach taps various technological and social solutions to academic dishonesty, integrating them into a…

Fair Leader Election for Rational Agents in Asynchronous Rings and Networks

OpenAIRE

Yifrach, Assaf; Mansour, Yishay

2018-01-01

We study a game theoretic model where a coalition of processors might collude to bias the outcome of the protocol, where we assume that the processors always prefer any legitimate outcome over a non-legitimate one. We show that the problems of Fair Leader Election and Fair Coin Toss are equivalent, and focus on Fair Leader Election. Our main focus is on a directed asynchronous ring of $n$ processors, where we investigate the protocol proposed by Abraham et al. \\cite{abraham2013distributed} an...

Quivers of Bound Path Algebras and Bound Path Coalgebras

Directory of Open Access Journals (Sweden)

Dr. Intan Muchtadi

2010-09-01

Full Text Available bras and coalgebras can be represented as quiver (directed graph, and from quiver we can construct algebras and coalgebras called path algebras and path coalgebras. In this paper we show that the quiver of a bound path coalgebra (resp. algebra is the dual quiver of its bound path algebra (resp. coalgebra.

Expectation values of the e+PsH system

International Nuclear Information System (INIS)

Zhang, J.-Y.; Mitroy, J.

2007-01-01

Close to converged energies and expectation values for e + PsH are computed using a ground-state wave function consisting of 1500 explicitly correlated Gaussians. The best estimate of the e + PsH ∞ energy was -0.810 254 hartrees, which has a binding energy of 0.021 057 hartrees against dissociation into e + +PsH. The 2γ annihilation rate was 2.7508x10 9 s -1 . Binding energies and annihilation rates are also given for the different finite-mass variants of e + PsH. Comparisons between expectation values for e + PsH and PsH provide compelling evidence that the e + PsH ground state can be regarded as consisting of a weakly bound positron orbiting the PsH ground state

Asynchronous Two-Level Checkpointing Scheme for Large-Scale Adjoints in the Spectral-Element Solver Nek5000

Energy Technology Data Exchange (ETDEWEB)

Schanen, Michel; Marin, Oana; Zhang, Hong; Anitescu, Mihai

2016-01-01

Adjoints are an important computational tool for large-scale sensitivity evaluation, uncertainty quantification, and derivative-based optimization. An essential component of their performance is the storage/recomputation balance in which efficient checkpointing methods play a key role. We introduce a novel asynchronous two-level adjoint checkpointing scheme for multistep numerical time discretizations targeted at large-scale numerical simulations. The checkpointing scheme combines bandwidth-limited disk checkpointing and binomial memory checkpointing. Based on assumptions about the target petascale systems, which we later demonstrate to be realistic on the IBM Blue Gene/Q system Mira, we create a model of the expected performance of our checkpointing approach and validate it using the highly scalable Navier-Stokes spectralelement solver Nek5000 on small to moderate subsystems of the Mira supercomputer. In turn, this allows us to predict optimal algorithmic choices when using all of Mira. We also demonstrate that two-level checkpointing is significantly superior to single-level checkpointing when adjoining a large number of time integration steps. To our knowledge, this is the first time two-level checkpointing had been designed, implemented, tuned, and demonstrated on fluid dynamics codes at large scale of 50k+ cores.

Exoplanet dynamics. Asynchronous rotation of Earth-mass planets in the habitable zone of lower-mass stars.

Science.gov (United States)

Leconte, Jérémy; Wu, Hanbo; Menou, Kristen; Murray, Norman

2015-02-06

Planets in the habitable zone of lower-mass stars are often assumed to be in a state of tidally synchronized rotation, which would considerably affect their putative habitability. Although thermal tides cause Venus to rotate retrogradely, simple scaling arguments tend to attribute this peculiarity to the massive Venusian atmosphere. Using a global climate model, we show that even a relatively thin atmosphere can drive terrestrial planets' rotation away from synchronicity. We derive a more realistic atmospheric tide model that predicts four asynchronous equilibrium spin states, two being stable, when the amplitude of the thermal tide exceeds a threshold that is met for habitable Earth-like planets with a 1-bar atmosphere around stars more massive than ~0.5 to 0.7 solar mass. Thus, many recently discovered terrestrial planets could exhibit asynchronous spin-orbit rotation, even with a thin atmosphere. Copyright © 2015, American Association for the Advancement of Science.

READ-EVAL-PRINT in Parallel and Asynchronous Proof-checking

Directory of Open Access Journals (Sweden)

Makarius Wenzel

2013-07-01

Full Text Available The LCF tradition of interactive theorem proving, which was started by Milner in the 1970-ies, appears to be tied to the classic READ-EVAL-PRINT-LOOP of sequential and synchronous evaluation of prover commands. We break up this loop and retrofit the read-eval-print phases into a model of parallel and asynchronous proof processing. Thus we explain some key concepts of the Isabelle/Scala approach to prover interaction and integration, and the Isabelle/jEdit Prover IDE as front-end technology. We hope to open up the scientific discussion about non-trivial interaction models for ITP systems again, and help getting other old-school proof assistants on a similar track.

Student Perceptions of Asynchronous and Synchronous Web Based Tools and Perceived Attainment of Academic Outcomes

Science.gov (United States)

Parenti, Melissa A.

2013-01-01

With an increasing presence and continual adaptations related to distance learning, there is a recognized need for up-to-date research in the area of effectiveness of online education programs. More specifically, assessing the capacity to attain academic goals by use of asynchronous and synchronous web based tools within Learning Management…

Asynchronous glaciations in arid continental climate

Science.gov (United States)

Batbaatar, Jigjidsurengiin; Gillespie, Alan R.; Fink, David; Matmon, Ari; Fujioka, Toshiyuki

2018-02-01

Mountain glaciers at ∼26-19 ka, during the global Last Glacial Maximum near the end of the last 105 yr glacial cycle, are commonly considered on the basis of dating and field mapping in several well-studied areas to have been the largest of the late Quaternary and to have advanced synchronously from region to region. However, a numerical sensitivity model (Rupper and Roe, 2008) predicts that the fraction of ablation due to melting varies across Central Asia in proportion to the annual precipitation. The equilibrium-line altitude of glaciers across this region likely varies accordingly: in high altitude, cold and arid regions sublimation can ablate most of the ice, whereas glaciers fed by high precipitation cannot ablate completely due to sublimation alone, but extend downhill until higher temperatures there cause them to melt. We have conducted field studies and 10Be dating at five glaciated sites along a precipitation gradient in Mongolia to test the Rupper/Roe model. The sites are located in nearby 1.875 × 1.875° cells of the Rupper/Roe model, each with a different melt fraction, in this little-studied region. The modern environment of the sites ranges from dry subhumid in the north (47.7° N) to arid in the south (45° N). Our findings show that the maximum local advances in the dry subhumid conditions predated the global Last Glacial Maximum and were likely from MIS 3. However, we also found that at ∼8-7 ka a cirque glacier in one mountain range of the arid Gobi desert grew to a magnitude comparable to that of the local maximum extent. This Holocene maximum occurred during a regional pluvial period thousands of years after the retreat of the Pleistocene glaciers globally. This asynchronous behavior is not predicted by the prevailing and generally correct presumption that glacier advances are dominantly driven by temperature, although precipitation also plays a role. Our findings are consistent with and support the Rupper/Roe model, which calls for

Real-Time Implementation of an Asynchronous Vision-Based Target Tracking System for an Unmanned Aerial Vehicle

Science.gov (United States)

2007-06-01

Chin Khoon Quek. “Vision Based Control and Target Range Estimation for Small Unmanned Aerial Vehicle.” Master’s Thesis, Naval Postgraduate School...December 2005. [6] Kwee Chye Yap. “Incorporating Target Mensuration System for Target Motion Estimation Along a Road Using Asynchronous Filter

Setting Optimal Bounds on Risk in Asset Allocation - a Convex Program

Directory of Open Access Journals (Sweden)

James E. Falk

2002-10-01

Full Text Available The 'Portfolio Selection Problem' is traditionally viewed as selecting a mix of investment opportunities that maximizes the expected return subject to a bound on risk. However, in reality, portfolios are made up of a few 'asset classes' that consist of similar opportunities. The asset classes are managed by individual `sub-managers', under guidelines set by an overall portfolio manager. Once a benchmark (the `strategic' allocation has been set, an overall manager may choose to allow the sub-managers some latitude in which opportunities make up the classes. He may choose some overall bound on risk (as measured by the variance and wish to set bounds that constrain the submanagers. Mathematically we show that the problem is equivalent to finding a hyper-rectangle of maximal volume within an ellipsoid. It is a convex program, albeit with potentially a large number of constraints. We suggest a cutting plane algorithm to solve the problem and include computational results on a set of randomly generated problems as well as a real-world problem taken from the literature.

MODELING OF SYMMETRIC THREE-PHASE ASYNCHRONOUS ELECTRIC MOTOR IN ASYMMETRIC CONNECTION TO NETWORK

Directory of Open Access Journals (Sweden)

V. I. Lukovnikov

2005-01-01

Full Text Available The paper shows how to solve the problem concerning reveal of changes in mathematical models and electric parameters of symmetric three-phase short-circuited asynchronous electric motors in case of their connection to single- or two-phase network in comparison with their connection to three-phase network. The uniform methodological approach permitting to generalize the known data and receive new results is offered in the paper.

Photon virtual bound state

International Nuclear Information System (INIS)

Inoue, J.; Ohtaka, K.

2004-01-01

We study virtual bound states in photonics, which are a vectorial extension of electron virtual bound states. The condition for these states is derived. It is found that the Mie resonant state which satisfies the condition that the size parameter is less than the angular momentum should be interpreted as a photon virtual bound state. In order to confirm the validity of the concept, we compare the photonic density of states, the width of which represents the lifetime of the photon virtual bound states, with numerical results

Managing Asynchronous Data in ATLAS's Concurrent Framework

CERN Document Server

Baines, John; The ATLAS collaboration

2016-01-01

In order to be able to make effective use of emerging hardware, where the amount of memory available to any CPU is rapidly decreasing as the core count continues to rise, ATLAS has begun a migration to a concurrent, multi-threaded software framework, known as AthenaMT. Significant progress has been made in implementing AthenaMT - we can currently run realistic Geant4 simulations on massively concurrent machines. the migration of realistic prototypes of reconstruction workflows is more difficult, given the large amounts of legacy code and the complexity and challenges of reconstruction software. These types of workflows, however, are the types that will most benefit from the memory reduction features of a multi-threaded framework. One of the challenges that we will report on in this paper is the re-design and implementation of several key asynchronous technologies whose behaviour is radically different in a concurrent environment than in a serial one, namely the management of Conditions data and the Detector D...

HiggsBounds 2.0.0. Confronting neutral and charged Higgs sector predictions with exclusion bounds from LEP and the Tevatron

Energy Technology Data Exchange (ETDEWEB)

Bechtle, P.; Weiglein, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Brein, O. [Freiburg Univ. (Germany). Physikalisches Inst.; Heinemeyer, S. [Instituto de Fisica de Cantabria (CSIC-UC), Santander (Spain); Williams, K.E. [Bonn Univ. (Germany). Bethe Center for Theoretical Physics

2011-03-15

HiggsBounds 2.0.0 is a computer code which tests both neutral and charged Higgs sectors of arbitrary models against the current exclusion bounds from the Higgs searches at LEP and the Tevatron. As input, it requires a selection of model predictions, such as Higgs masses, branching ratios, effective couplings and total decay widths. HiggsBounds 2.0.0 then uses the expected and observed topological cross section limits from the Higgs searches to determine whether a given parameter scenario of a model is excluded at the 95% C.L. by those searches. Version 2.0.0 represents a significant extension of the code since its first release (1.0.0). It includes now 28/53 LEP/Tevatron Higgs search analyses, compared to the 11/22 in the first release, of which many of the ones from the Tevatron are replaced by updates. As a major extension, the code allows now the predictions for (singly) charged Higgs bosons to be confronted with LEP and Tevatron searches. Furthermore, the newly included analyses contain LEP searches for neutral Higgs bosons (H) decaying invisibly or into (non flavour tagged) hadrons as well as decay-mode independent searches for neutral Higgs bosons, LEP searches via the production modes {tau}{sup +}{tau}{sup -}H and b anti bH, and Tevatron searches via t anti tH. Also, all Tevatron results presented at the ICHEP'10 are included in version 2.0.0. As physics applications of HiggsBounds 2.0.0 we study the allowed Higgs mass range for model scenarios with invisible Higgs decays and we obtain exclusion results for the scalar sector of the Randall-Sundrum model using up-to-date LEP and Tevatron direct search results. (orig.)

A 0.8mW 5bit 250MS/s time-interleaved asynchronous digital slope ADC

NARCIS (Netherlands)

Harpe, P.J.A.; Zhou, C.; Philips, K.J.P.; Groot, de H.W.H.

2011-01-01

Slope and digital-ramp converters are normally limited to very low sampling rates, since they require a digital counter at a highly oversampled clock rate. In this work, an asynchronous digital slope architecture is introduced that only requires a nonoversampled clock, thus enabling a much higher

Asynchronous CMC, Collaboration and the Development of Critical Thinking in a Graduate Seminar in Applied Linguistics

Science.gov (United States)

Abrams, Zsuzsanna I.

2005-01-01

A primary objective of graduate education, and often promoted by peer collaboration tasks, is the development of critical thinking skills. The present study compares how graduate students enrolled in a qualitative research design course in applied linguistics utilized asynchronous computer-mediated communication (ACMC) and face-to-face…

Dynamic bounds coupled with Monte Carlo simulations

Energy Technology Data Exchange (ETDEWEB)

Rajabalinejad, M., E-mail: M.Rajabalinejad@tudelft.n [Faculty of Civil Engineering, Delft University of Technology, Delft (Netherlands); Meester, L.E. [Delft Institute of Applied Mathematics, Delft University of Technology, Delft (Netherlands); Gelder, P.H.A.J.M. van; Vrijling, J.K. [Faculty of Civil Engineering, Delft University of Technology, Delft (Netherlands)

2011-02-15

For the reliability analysis of engineering structures a variety of methods is known, of which Monte Carlo (MC) simulation is widely considered to be among the most robust and most generally applicable. To reduce simulation cost of the MC method, variance reduction methods are applied. This paper describes a method to reduce the simulation cost even further, while retaining the accuracy of Monte Carlo, by taking into account widely present monotonicity. For models exhibiting monotonic (decreasing or increasing) behavior, dynamic bounds (DB) are defined, which in a coupled Monte Carlo simulation are updated dynamically, resulting in a failure probability estimate, as well as a strict (non-probabilistic) upper and lower bounds. Accurate results are obtained at a much lower cost than an equivalent ordinary Monte Carlo simulation. In a two-dimensional and a four-dimensional numerical example, the cost reduction factors are 130 and 9, respectively, where the relative error is smaller than 5%. At higher accuracy levels, this factor increases, though this effect is expected to be smaller with increasing dimension. To show the application of DB method to real world problems, it is applied to a complex finite element model of a flood wall in New Orleans.

Asynchronous Amazon Forest Canopy Phenology Indicates Adaptation to Both Water and Light Availability

Science.gov (United States)

Jones, M. O.; Kimball, J. S.; Nemani, R. R.

2015-12-01

Amazon forests represent nearly half of all tropical vegetation biomass and, through photosynthesis and respiration, annually process more than twice the amount of estimated carbon (CO2) from fossil fuel emissions. Yet the seasonality of Amazon canopy cover, and the extent to which seasonal fluctuations in water availability and photosynthetically active radiation influence these processes, is still poorly understood. Implementing six remotely sensed data sets spanning nine years (2003-2011), with reported field and flux tower data, we show that southern equatorial Amazon forests exhibit a distinctive seasonal signal. Seasonal timing of water availability, canopy biomass growth and net leaf flush are asynchronous in regions with short dry seasons and become more synchronous across a west-to-east longitudinal moisture gradient of increasing dry season length. Forest cover is responsive to seasonal disparities in both water and solar radiation availability, temporally adjusting net leaf flush to maximize use of these generally abundant resources, while reducing drought susceptibility. An accurate characterization of this asynchronous behavior allows for improved understanding of canopy phenology across contiguous tropical forests and their sensitivity to climate variability and drought. These insights can also inform land surface models to provide a more accurate representation of seasonal forest carbon allocation strategies responsive to environmental drivers.

Growth Patterns and E-Moderating Supports in Asynchronous Online Discussions in an Undergraduate Blended Course

Science.gov (United States)

Ghadirian, Hajar; Ayub, Ahmad Fauzi Mohd; Bakar, Kamariah Binti Abu; Hassanzadeh, Maryam

2016-01-01

This study presents a case study of asynchronous online discussions' (AOD) growth patterns in an undergraduate blended course to address the gap in our current understanding of how threads are developed in peer-moderated AODs. Building on a taxonomy of thread pattern proposed by Chan, Hew and Cheung (2009), growth patterns of thirty-six forums…

Credit Hours with No Set Time: A Study of Credit Policies in Asynchronous Online Education

Science.gov (United States)

Prasuhn, Frederick Carl

2014-01-01

U.S. public university system policies were examined to learn how credit hours were determined for asynchronous online education. Findings indicated that (a) credit hour meaning and use are not consistent, (b) primary responsibility for credit hour decisions was at the local level, and (c) no policies exist to guide credit hour application for…

Testing bounded rationality against full rationality in job changing behavior

OpenAIRE

Contini, Bruno; Morini, Matteo

2007-01-01

In this paper we question the hypothesis of full rationality in the context of job changing behaviour, via simple econometric explorations on microdata drawn from WHIP (Worker Histories Italian Panel). Workers' performance is compared at the end of a three-year time window that starts when choices are expressed, under the accepted notion that the main driving forces of job change are future real wages and expected job quality. Bounded rationality suggests that individuals will search for new ...

Testing Bounded Rationality Against Full Rationality in Job Changing Behavior

OpenAIRE

Bruno Contini

2008-01-01

In this paper I question the hypothesis of full rationality in the context of job changing behaviour, via simple econometric explorations on microdata drawn from WHIP (Worker Histories Italian Panel). Workers’ performance is compared at the end of a three-year time window that starts when choices are expressed, under the accepted notion that the main driving forces of job change are future real wages and expected job quality. Bounded rationality suggests that individuals will search for new o...

An Asynchronous Cellular Automata-Based Adaptive Illumination Facility

Science.gov (United States)

Bandini, Stefania; Bonomi, Andrea; Vizzari, Giuseppe; Acconci, Vito

The term Ambient Intelligence refers to electronic environments that are sensitive and responsive to the presence of people; in the described scenario the environment itself is endowed with a set of sensors (to perceive humans or other physical entities such as dogs, bicycles, etc.), interacting with a set of actuators (lights) that choose their actions (i.e. state of illumination) in an attempt improve the overall experience of these users. The model for the interaction and action of sensors and actuators is an asynchronous Cellular Automata (CA) with memory, supporting a self-organization of the system as a response to the presence and movements of people inside it. The paper will introduce the model, as well as an ad hoc user interface for the specification of the relevant parameters of the CA transition rule that determines the overall system behaviour.

RESEARCH INTO VALVE-ENGINE TRANSDUCERS OF BRUSHLESS SYNCHRONOUS AND ASYNCHRONIZED MACHINES IN A CIRCUIT SIMULATION SYSTEM.

Directory of Open Access Journals (Sweden)

A.M. Galynovskiy

2013-10-01

Full Text Available Designing features for valve-engine transducers of brushless synchronous and asynchronized machines are described. Global analysis of research results on the transducer models in a MicroCap circuit simulation system is made, recommendations on the simulation system application in both scientific research and educational process given.

Lower bounds on the run time of the univariate marginal distribution algorithm on OneMax

DEFF Research Database (Denmark)

Krejca, Martin S.; Witt, Carsten

2017-01-01

The Univariate Marginal Distribution Algorithm (UMDA), a popular estimation of distribution algorithm, is studied from a run time perspective. On the classical OneMax benchmark function, a lower bound of Ω(μ√n + n log n), where μ is the population size, on its expected run time is proved...... values maintained by the algorithm, including carefully designed potential functions. These techniques may prove useful in advancing the field of run time analysis for estimation of distribution algorithms in general........ This is the first direct lower bound on the run time of the UMDA. It is stronger than the bounds that follow from general black-box complexity theory and is matched by the run time of many evolutionary algorithms. The results are obtained through advanced analyses of the stochastic change of the frequencies of bit...

A prototype pixel readout chip for asynchronous detection applications

International Nuclear Information System (INIS)

Raymond, D.M.; Hall, G.; Lewis, A.J.; Sharp, P.H.

1991-01-01

A two-dimensional array of amplifier cells has been fabricated as a prototype readout system for a matching array of silicon diode detectors. Each cell contains a preamplifier, shaping amplifier, comparator and analogue signal storage in an area of 300 μmx320 μm using 3 μm CMOS technology. Full size chips will be bump bonded to pixel detector arrays. Low noise and asynchronous operation are novel design features. With noise levels of less than 250 rms electrons for input capacitances up to 600 fF, pixel detectors will be suitable for autoradiography, synchrotron X-ray and high energy particle detection applications. The design of the prototype chip is presented and future developments and prospects for applications are discussed. (orig.)

Asynchronous transfer mode and Local Area Network emulation standards, protocols, and security implications

OpenAIRE

Kirwin, John P.

1999-01-01

A complex networking technology called Asynchronous Transfer Mode (ATM) and a networking protocol called Local Area Network Emulation (LANE) are being integrated into many naval networks without any security-driven naval configuration guidelines. No single publication is available that describes security issues of data delivery and signaling relating to the transition of Ethernet to LANE and ATM. The thesis' focus is to provide: (1) an overview and security analysis of standardized protocols ...

Asynchronous response of tropical forest leaf phenology to seasonal and el Niño-driven drought.

Directory of Open Access Journals (Sweden)

Stephanie Pau

2010-06-01

Full Text Available The Hawaiian Islands are an ideal location to study the response of tropical forests to climate variability because of their extreme isolation in the middle of the Pacific, which makes them especially sensitive to El Niño-Southern Oscillation (ENSO. Most research examining the response of tropical forests to drought or El Niño have focused on rainforests, however, tropical dry forests cover a large area of the tropics and may respond very differently than rainforests. We use satellite-derived Normalized Difference Vegetation Index (NDVI from February 2000-February 2009 to show that rainforests and dry forests in the Hawaiian Islands exhibit asynchronous responses in leaf phenology to seasonal and El Niño-driven drought. Dry forest NDVI was more tightly coupled with precipitation compared to rainforest NDVI. Rainforest cloud frequency was negatively correlated with the degree of asynchronicity (Delta(NDVI between forest types, most strongly at a 1-month lag. Rainforest green-up and dry forest brown-down was particularly apparent during the 2002-003 El Niño. The spatial pattern of NDVI response to the NINO 3.4 Sea Surface Temperature (SST index during 2002-2003 showed that the leeward side exhibited significant negative correlations to increased SSTs, whereas the windward side exhibited significant positive correlations to increased SSTs, most evident at an 8 to 9-month lag. This study demonstrates that different tropical forest types exhibit asynchronous responses to seasonal and El Niño-driven drought, and suggests that mechanisms controlling dry forest leaf phenology are related to water-limitation, whereas rainforests are more light-limited.

An corrective method to correct of the inherent flaw of the asynchronization direct counting circuit

International Nuclear Information System (INIS)

Wang Renfei; Liu Congzhan; Jin Yongjie; Zhang Zhi; Li Yanguo

2003-01-01

As a inherent flaw of the Asynchronization Direct Counting Circuit, the crosstalk, which is resulted from the randomicity of the time-signal always exists between two adjacent channels. In order to reduce the counting error derived from the crosstalk, the author propose an effective method to correct the flaw after analysing the mechanism of the crosstalk

Dynamic pricing of network goods with boundedly rational consumers.

Science.gov (United States)

Radner, Roy; Radunskaya, Ami; Sundararajan, Arun

2014-01-07

We present a model of dynamic monopoly pricing for a good that displays network effects. In contrast with the standard notion of a rational-expectations equilibrium, we model consumers as boundedly rational and unable either to pay immediate attention to each price change or to make accurate forecasts of the adoption of the network good. Our analysis shows that the seller's optimal price trajectory has the following structure: The price is low when the user base is below a target level, is high when the user base is above the target, and is set to keep the user base stationary once the target level has been attained. We show that this pricing policy is robust to a number of extensions, which include the product's user base evolving over time and consumers basing their choices on a mixture of a myopic and a "stubborn" expectation of adoption. Our results differ significantly from those that would be predicted by a model based on rational-expectations equilibrium and are more consistent with the pricing of network goods observed in practice.

Strongest model-independent bound on the lifetime of Dark Matter

CERN Document Server

Audren, Benjamin; Mangano, Gianpiero; Serpico, Pasquale Dario; Tram, Thomas

2014-01-01

Dark Matter is essential for structure formation in the late Universe so it must be stable on cosmological time scales. But how stable exactly? Only assuming decays into relativistic particles, we report an otherwise model independent bound on the lifetime of Dark Matter using current cosmological data. Since these decays affect only the low-$\\ell$ multipoles of the CMB, the Dark Matter lifetime is expected to correlate with the tensor-to-scalar ratio $r$ as well as curvature $\\Omega_k$. We consider two models, including $r$ and $r+\\Omega_k$ respectively, versus data from Planck, WMAP, WiggleZ and Baryon Acoustic Oscillations, with or without the BICEP2 data (if interpreted in terms of primordial gravitational waves). This results in a lower bound on the lifetime of CDM given by 160Gyr (without BICEP2) or 200Gyr (with BICEP2) at 95% confidence level.

Bounded Delay Timing Analysis of a Class of CSP Programs

DEFF Research Database (Denmark)

Hulgaard, Henrik; Burns, Steven M.

1997-01-01

We describe an algebraic technique for performing timing analysis of a class of asynchronous circuits described as CSP programs (including Martin's probe operator) with the restrictions that there is no OR-causality and that guard selection is either completely free or mutually exclusive...

Curvature bound from gravitational catalysis

Science.gov (United States)

Gies, Holger; Martini, Riccardo

2018-04-01

We determine bounds on the curvature of local patches of spacetime from the requirement of intact long-range chiral symmetry. The bounds arise from a scale-dependent analysis of gravitational catalysis and its influence on the effective potential for the chiral order parameter, as induced by fermionic fluctuations on a curved spacetime with local hyperbolic properties. The bound is expressed in terms of the local curvature scalar measured in units of a gauge-invariant coarse-graining scale. We argue that any effective field theory of quantum gravity obeying this curvature bound is safe from chiral symmetry breaking through gravitational catalysis and thus compatible with the simultaneous existence of chiral fermions in the low-energy spectrum. With increasing number of dimensions, the curvature bound in terms of the hyperbolic scale parameter becomes stronger. Applying the curvature bound to the asymptotic safety scenario for quantum gravity in four spacetime dimensions translates into bounds on the matter content of particle physics models.

Nonperturbative bounds on in cutoff (lambdaphi/sup n/)/sub d/ field theory

International Nuclear Information System (INIS)

Doering, C.R.

1985-01-01

Stochastic quantization is used to obtain upper and lower bounds on the vacuum expectation value of phi/sup n/ in a cutoff lambdaphi/sup n/ scalar theory in d dimensions. These determine the behavior of as the cutoff is removed. The results are given by formulas which depend on whether the values of n and d define a perturbatively superrenormalizable, strictly renormalizable, or nonrenormalizable theory

Asynchronous P300-Based Brain-Computer Interface to Control a Virtual Environment : Initial Tests on End Users

NARCIS (Netherlands)

Aloise, Fabio; Schettini, Francesca; Arico, Pietro; Salinari, Serenella; Guger, Christoph; Rinsma, Johanna; Aiello, Marco; Mattia, Donatella; Cincotti, Febo

2011-01-01

Motor disability and/or ageing can prevent individuals from fully enjoying home facilities, thus worsening their quality of life. Advances in the field of accessible user interfaces for domotic appliances can represent a valuable way to improve the independence of these persons. An asynchronous

Fluka Studies of the Asynchronous Beam Dump Effects on LHC Point 6 for a 7 TeV beam

CERN Document Server

VERSACI, R; GODDARD, B; MEREGHETTI, A; SCHMIDT, R; VLACHOUDIS, V

2012-01-01

The LHC is a record-breaking machine for beam energy and intensity. An intense effort has therefore been deployed in simulating critical operational scenarios of energy deposition. Using FLUKA Monte Carlo simulations, we have investigated the effects of an asynchronous beam dump at the LHC Point 6 where beams, with a stored energy of 360 MJ, can instantaneously release up to a few J cm^{-3} in the cryogenic magnets which have a quench limit of the order of the mJ cm^{-3}. In the present paper we will describe the simulation approach, and discuss the evaluated maximum energy release onto the superconducting magnets during an asynchronous beam dump of a 7 TeV beam. We will then analyze the shielding provided by collimators installed in the area and discuss safety limits for the operation of the LHC.

Deeply bound pionic atom

International Nuclear Information System (INIS)

Toki, Hiroshi; Yamazaki, Toshimitsu

1989-01-01

The standard method of pionic atom formation does not produce deeply bound pionic atoms. A study is made on the properties of deeply bound pionic atom states by using the standard pion-nucleus optical potential. Another study is made to estimate the cross sections of the formation of ls pionic atom states by various methods. The pion-nucleus optical potential is determined by weakly bound pionic atom states and pion nucleus scattering. Although this potential may not be valid for deeply bound pionic atoms, it should provide some hint on binding energies and level widths of deeply bound states. The width of the ls state comes out to be 0.3 MeV and is well separated from the rest. The charge dependence of the ls state is investigated. The binding energies and the widths increase linearly with Z azbove a Z of 30. The report then discusses various methods to populate deeply bound pionic atoms. In particular, 'pion exchange' reactions are proposed. (n, pπ) reaction is discussed first. The cross section is calculated by assuming the in- and out-going nucleons on-shell and the produced pion in (n1) pionic atom states. Then, (n, dπ - ) cross sections are estimated. (p, 2 Heπ - ) reaction would have cross sections similar to the cross section of (n, dπ - ) reaction. In conclusion, it seems best to do (n, p) experiment on heavy nuclei for deeply bound pionic atom. (Nogami, K.)

Reactions with weakly bound nuclei at near barrier energies

International Nuclear Information System (INIS)

Nanal, Vandana

2014-01-01

In reactions with weakly bound nuclei, the effect of breakup on fusion process has attracted much attention in recent years. The experimental study shows that breakup channel leads to suppression of complete fusion at above barrier energies due to loss of flux. The fusion barrier distribution can provide a further insight into understanding the influence of coupling to the breakup channels. Similar information could be obtained from the elastic and quasielastic (QEL) scattering because of the conservation of the reaction flux (i.e. R+T= 1), where R is the reflection probability and T is the transmission probability. Thus, quasi-elastic scattering at backward angles is the counterpart of the fusion process and it is expected that the barrier distributions extracted from two processes, namely, QEL and fusion should be similar. While this is true for tightly bound reaction systems, in reactions involving weakly bound projectiles significant differences have been observed for QEL barrier distributions with and without inclusion of breakup processes. This talk will present the recent results for fusion and quasi-elastic scattering in "6","7Li + "1"9"7Au system. Developmental efforts towards a momentum achromatic separator, MARIE, to extract projectile-like secondary ion beams following the reactions of heavy-ion beams from superconducting LINAC booster at Mumbai will also be presented. (author)

Bounding species distribution models

Directory of Open Access Journals (Sweden)

Thomas J. STOHLGREN, Catherine S. JARNEVICH, Wayne E. ESAIAS,Jeffrey T. MORISETTE

2011-10-01

Full Text Available Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for “clamping” model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART and maximum entropy (Maxent models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5: 642–647, 2011].

Bounding Species Distribution Models

Science.gov (United States)

Stohlgren, Thomas J.; Jarnevich, Cahterine S.; Morisette, Jeffrey T.; Esaias, Wayne E.

2011-01-01

Species distribution models are increasing in popularity for mapping suitable habitat for species of management concern. Many investigators now recognize that extrapolations of these models with geographic information systems (GIS) might be sensitive to the environmental bounds of the data used in their development, yet there is no recommended best practice for "clamping" model extrapolations. We relied on two commonly used modeling approaches: classification and regression tree (CART) and maximum entropy (Maxent) models, and we tested a simple alteration of the model extrapolations, bounding extrapolations to the maximum and minimum values of primary environmental predictors, to provide a more realistic map of suitable habitat of hybridized Africanized honey bees in the southwestern United States. Findings suggest that multiple models of bounding, and the most conservative bounding of species distribution models, like those presented here, should probably replace the unbounded or loosely bounded techniques currently used [Current Zoology 57 (5): 642-647, 2011].

An Examination of Undergraduates' Metacognitive Strategies in Pre-Class Asynchronous Activity in a Flipped Classroom

Science.gov (United States)

Yilmaz, Rabia M.; Baydas, Ozlem

2017-01-01

The aim of the study is to examine undergraduate students' awareness of metacognition, the metacognitive strategies they use in their learning and their learning performance in pre-class asynchronous activity in a flipped classroom. The sample consisted of 47 undergraduate students. Eleven students were not included in this study since they did…

Factor Validity of the Motivated Strategies for Learning Questionnaire (MSLQ) in Asynchronous Online Learning Environments (AOLE)

Science.gov (United States)

Cho, Moon-Heum; Summers, Jessica

2012-01-01

The purpose of this study was to investigate the factor validity of the Motivated Strategies for Learning Questionnaire (MSLQ) in asynchronous online learning environments. In order to check the factor validity, confirmatory factor analysis (CFA) was conducted with 193 cases. Using CFA, it was found that the original measurement model fit for…

Bio-Inspired Asynchronous Pixel Event Tricolor Vision Sensor.

Science.gov (United States)

Lenero-Bardallo, Juan Antonio; Bryn, D H; Hafliger, Philipp

2014-06-01

This article investigates the potential of the first ever prototype of a vision sensor that combines tricolor stacked photo diodes with the bio-inspired asynchronous pixel event communication protocol known as Address Event Representation (AER). The stacked photo diodes are implemented in a 22 × 22 pixel array in a standard STM 90 nm CMOS process. Dynamic range is larger than 60 dB and pixels fill factor is 28%. The pixels employ either simple pulse frequency modulation (PFM) or a Time-to-First-Spike (TFS) mode. A heuristic linear combination of the chip's inherent pseudo colors serves to approximate RGB color representation. Furthermore, the sensor outputs can be processed to represent the radiation in the near infrared (NIR) band without employing external filters, and to color-encode direction of motion due to an asymmetry in the update rates of the different diode layers.

Students' Perceptions of Online Discussions, Participation and E-Moderation Behaviours in Peer-Moderated Asynchronous Online Discussions

Science.gov (United States)

Ghadirian, Hajar; Fauzi Mohd Ayub, Ahmad; Salehi, Keyvan

2018-01-01

The aim of this study was to investigate the relationships between students' perceptions of online discussions, participation and e-moderation behaviours in peer-moderated asynchronous online discussions. Using survey data, the learning system's activity log and discussion transcripts, the authors analysed how 84 learners' perceptions of online…

Self-Paced (Asynchronous BCI Control of a Wheelchair in Virtual Environments: A Case Study with a Tetraplegic

Directory of Open Access Journals (Sweden)

Robert Leeb

2007-09-01

Full Text Available The aim of the present study was to demonstrate for the first time that brain waves can be used by a tetraplegic to control movements of his wheelchair in virtual reality (VR. In this case study, the spinal cord injured (SCI subject was able to generate bursts of beta oscillations in the electroencephalogram (EEG by imagination of movements of his paralyzed feet. These beta oscillations were used for a self-paced (asynchronous brain-computer interface (BCI control based on a single bipolar EEG recording. The subject was placed inside a virtual street populated with avatars. The task was to “go” from avatar to avatar towards the end of the street, but to stop at each avatar and talk to them. In average, the participant was able to successfully perform this asynchronous experiment with a performance of 90%, single runs up to 100%.

The Nature of Elementary Science Teachers' Experiences with Synchronous Online, Asynchronous Online and Face-to-Face Coaching

Science.gov (United States)

Gilbert, Amanda M.

This study investigated the nature of instructional coaching interactions in three formats: online synchronous, online asynchronous, and face-to-face. Knight's (2007) Seven Partnership Principles of Instructional Coaching were used as a framework to analyze and compare the coaching interactions between coach and teacher to determine whether online coaching may be a viable option to provide support for the teachers unprepared to teach the new science standards. Some previous research has suggested that online communication can result in deeper personal interactions (Walther, 1996), while other studies suggest that interactions are more natural and easier in formats that are more similar to face-to-face interactions (Kock, 2005). The findings of this study support the media naturalness theory (Kock, 2005) and suggest that collaboration may be especially difficult in asynchronous online communication. Although differences were noted in the actual interactions, teacher perception remained fairly consistently positive across the three formats. Research beyond this exploratory study is needed to make findings generalizable.

Label-acquired magnetorotation for biosensing: An asynchronous rotation assay

International Nuclear Information System (INIS)

Hecht, Ariel; Kinnunen, Paivo; McNaughton, Brandon; Kopelman, Raoul

2011-01-01

This paper presents a novel application of magnetic particles for biosensing, called label-acquired magnetorotation (LAM). This method is based on a combination of the traditional sandwich assay format with the asynchronous magnetic bead rotation (AMBR) method. In label-acquired magnetorotation, an analyte facilitates the binding of a magnetic label bead to a nonmagnetic solid phase sphere, forming a sandwich complex. The sandwich complex is then placed in a rotating magnetic field, where the rotational frequency of the sandwich complex is a function of the amount of analyte attached to the surface of the sphere. Here, we use streptavidin-coated beads and biotin-coated particles as analyte mimics, to be replaced by proteins and other biological targets in future work. We show this sensing method to have a dynamic range of two orders of magnitude.

Sensor placement on Canton Tower for health monitoring using asynchronous-climb monkey algorithm

Science.gov (United States)

Yi, Ting-Hua; Li, Hong-Nan; Zhang, Xu-Dong

2012-12-01

Heuristic optimization algorithms have become a popular choice for solving complex and intricate sensor placement problems which are difficult to solve by traditional methods. This paper proposes a novel and interesting methodology called the asynchronous-climb monkey algorithm (AMA) for the optimum design of sensor arrays for a structural health monitoring system. Different from the existing algorithms, the dual-structure coding method is designed and adopted for the representation of the design variables. The asynchronous-climb process is incorporated in the proposed AMA that can adjust the trajectory of each individual dynamically in the search space according to its own experience and other monkeys. The concept of ‘monkey king’ is introduced in the AMA, which reflects the Darwinian principle of natural selection and can create an interaction network to correctly guide the movement of other monkeys. Numerical experiments are carried out using two different objective functions by considering the Canton Tower in China with or without the antenna mast to evaluate the performance of the proposed algorithm. Investigations have indicated that the proposed AMA exhibits faster convergence characteristics and can generate sensor configurations superior in all instances when compared to the conventional monkey algorithm. For structures with stiffness mutation such as the Canton Tower, the sensor placement needs to be considered for each part separately.

Sensor placement on Canton Tower for health monitoring using asynchronous-climb monkey algorithm

International Nuclear Information System (INIS)

Yi, Ting-Hua; Li, Hong-Nan; Zhang, Xu-Dong

2012-01-01

Heuristic optimization algorithms have become a popular choice for solving complex and intricate sensor placement problems which are difficult to solve by traditional methods. This paper proposes a novel and interesting methodology called the asynchronous-climb monkey algorithm (AMA) for the optimum design of sensor arrays for a structural health monitoring system. Different from the existing algorithms, the dual-structure coding method is designed and adopted for the representation of the design variables. The asynchronous-climb process is incorporated in the proposed AMA that can adjust the trajectory of each individual dynamically in the search space according to its own experience and other monkeys. The concept of ‘monkey king’ is introduced in the AMA, which reflects the Darwinian principle of natural selection and can create an interaction network to correctly guide the movement of other monkeys. Numerical experiments are carried out using two different objective functions by considering the Canton Tower in China with or without the antenna mast to evaluate the performance of the proposed algorithm. Investigations have indicated that the proposed AMA exhibits faster convergence characteristics and can generate sensor configurations superior in all instances when compared to the conventional monkey algorithm. For structures with stiffness mutation such as the Canton Tower, the sensor placement needs to be considered for each part separately. (paper)

Data-Aware Retrodiction for Asynchronous Harmonic Measurement in a Cyber-Physical Energy System

Science.gov (United States)

Liu, Youda; Wang, Xue; Liu, Yanchi; Cui, Sujin

2016-01-01

Cyber-physical energy systems provide a networked solution for safety, reliability and efficiency problems in smart grids. On the demand side, the secure and trustworthy energy supply requires real-time supervising and online power quality assessing. Harmonics measurement is necessary in power quality evaluation. However, under the large-scale distributed metering architecture, harmonic measurement faces the out-of-sequence measurement (OOSM) problem, which is the result of latencies in sensing or the communication process and brings deviations in data fusion. This paper depicts a distributed measurement network for large-scale asynchronous harmonic analysis and exploits a nonlinear autoregressive model with exogenous inputs (NARX) network to reorder the out-of-sequence measuring data. The NARX network gets the characteristics of the electrical harmonics from practical data rather than the kinematic equations. Thus, the data-aware network approximates the behavior of the practical electrical parameter with real-time data and improves the retrodiction accuracy. Theoretical analysis demonstrates that the data-aware method maintains a reasonable consumption of computing resources. Experiments on a practical testbed of a cyber-physical system are implemented, and harmonic measurement and analysis accuracy are adopted to evaluate the measuring mechanism under a distributed metering network. Results demonstrate an improvement of the harmonics analysis precision and validate the asynchronous measuring method in cyber-physical energy systems. PMID:27548171

Labeling schemes for bounded degree graphs

DEFF Research Database (Denmark)

Adjiashvili, David; Rotbart, Noy Galil

2014-01-01

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

Full-asynchronous gigabit-symmetric DPSK downstream and OOK upstream OCDMA-PON with source-free ONUs employing all-optical self-clocked time gate.

Science.gov (United States)

Dai, Bo; Shimizu, Satoshi; Wang, Xu; Wada, Naoya

2012-12-10

We propose an asynchronous gigabit-symmetric optical code division multiplexing access passive optical network (OCDMA-PON) in which optical network units (ONUs) are source-free. In the experiment, we demonstrate a duplex OCDMA system with a 50 km 10 Gbit/s/user 4-user DPSK-OCDMA downlink and a 50 km 10 Gbit/s/user 4-user OOK-OCDMA uplink and error-free duplex transmissions are achieved. Besides, we investigate an all-optical self-clocked time gate, which is used for the signal regeneration of decoded signals and ensures asynchronization in the up/downstream transmissions. Furthermore, we evaluate the power budget of the proposed duplex transmission.

Increased Mass Loss and Asynchronous Behavior of Marine-Terminating Outlet Glaciers at Upernavik Isstrøm, NW Greenland

DEFF Research Database (Denmark)

Larsen, Signe Hillerup; Khan, Shfaqat Abbas; Ahlstrøm, Andreas Peter

2016-01-01

In order to model and predict future behavior of marine terminating glaciers, it is essential to understand the different factors that control a glaciers response to climate change. Here we present a detailed study of the asynchronous changes in dynamic behavior of four adjacent marine...... between 1992 and 2013. These observations point out the fact that the UI glaciers are reacting to climate change on different timescales. The asynchronous behavior of the four neighboring glaciers is explained in terms of the individual glaciersâĂŹ geometry and terminus position. The northernmost glacier...... is believed to have had a floating tongue between 1985 and 2007 which disintegrated in 2007-2008. This release of back stress destabilized the glacier causing it to accelerate and thin rapidly. We suggest that the ice tongue broke up due to ocean-warming induced thinning in the late 1990s. Recent response...

Effects of Synchronous and Asynchronous Computer-Mediated Communication (CMC) Oral Conversations on English Language Learners' Discourse Functions

Science.gov (United States)

AbuSeileek, Ali Farhan; Qatawneh, Khaleel

2013-01-01

This study aimed to explore the effects of synchronous and asynchronous computer mediated communication (CMC) oral discussions on question types and strategies used by English as a Foreign Language (EFL) learners. The participants were randomly assigned to two treatment conditions/groups; the first group used synchronous CMC, while the second…

An Investigation of Native and Nonnative English Speakers' Levels of Written Syntactic Complexity in Asynchronous Online Discussions

Science.gov (United States)

Mancilla, Rae L.; Polat, Nihat; Akcay, Ahmet O.

2017-01-01

This manuscript reports on a corpus-based comparison of native and nonnative graduate students' language production in an asynchronous learning environment. Using 486 discussion board postings from a five-year period (2009-2013), we analyzed the extent to which native and nonnative university students' writing differed in 10 measures of syntactic…

A Quantitative Study of Faculty Perceptions and Attitudes on Asynchronous Virtual Teamwork Using the Technology Acceptance Model

Science.gov (United States)

Wolusky, G. Anthony

2016-01-01

This quantitative study used a web-based questionnaire to assess the attitudes and perceptions of online and hybrid faculty towards student-centered asynchronous virtual teamwork (AVT) using the technology acceptance model (TAM) of Davis (1989). AVT is online student participation in a team approach to problem-solving culminating in a written…

A Dynamic Analysis of the Interplay between Asynchronous and Synchronous Communication in Online Learning: The Impact of Motivation

Science.gov (United States)

Giesbers, B.; Rienties, B.; Tempelaar, D.; Gijselaers, W.

2014-01-01

With the increased affordances of synchronous communication tools, more opportunities for online learning to resemble face-to-face settings have recently become available. However, synchronous communication does not afford as much time for reflection as asynchronous communication. Therefore, a combination of synchronous and asynchronous…

Fast Simulation of Mechanical Heterogeneity in the Electrically Asynchronous Heart Using the MultiPatch Module.

Directory of Open Access Journals (Sweden)

John Walmsley

2015-07-01

Full Text Available Cardiac electrical asynchrony occurs as a result of cardiac pacing or conduction disorders such as left bundle-branch block (LBBB. Electrically asynchronous activation causes myocardial contraction heterogeneity that can be detrimental for cardiac function. Computational models provide a tool for understanding pathological consequences of dyssynchronous contraction. Simulations of mechanical dyssynchrony within the heart are typically performed using the finite element method, whose computational intensity may present an obstacle to clinical deployment of patient-specific models. We present an alternative based on the CircAdapt lumped-parameter model of the heart and circulatory system, called the MultiPatch module. Cardiac walls are subdivided into an arbitrary number of patches of homogeneous tissue. Tissue properties and activation time can differ between patches. All patches within a wall share a common wall tension and curvature. Consequently, spatial location within the wall is not required to calculate deformation in a patch. We test the hypothesis that activation time is more important than tissue location for determining mechanical deformation in asynchronous hearts. We perform simulations representing an experimental study of myocardial deformation induced by ventricular pacing, and a patient with LBBB and heart failure using endocardial recordings of electrical activation, wall volumes, and end-diastolic volumes. Direct comparison between simulated and experimental strain patterns shows both qualitative and quantitative agreement between model fibre strain and experimental circumferential strain in terms of shortening and rebound stretch during ejection. Local myofibre strain in the patient simulation shows qualitative agreement with circumferential strain patterns observed in the patient using tagged MRI. We conclude that the MultiPatch module produces realistic regional deformation patterns in the asynchronous heart and that

Indoor Positioning for Smartphones Using Asynchronous Ultrasound Trilateration

Directory of Open Access Journals (Sweden)

James D. Carswell

2013-06-01

Full Text Available Modern smartphones are a great platform for Location Based Services (LBS. While outdoor LBS for smartphones has proven to be very successful, indoor LBS for smartphones has not yet fully developed due to the lack of an accurate positioning technology. In this paper we present an accurate indoor positioning approach for commercial off-the-shelf (COTS smartphones that uses the innate ability of mobile phones to produce ultrasound, combined with Time-Difference-of-Arrival (TDOA asynchronous trilateration. We evaluate our indoor positioning approach by describing its strengths and weaknesses, and determine its absolute accuracy. This is accomplished through a range of experiments that involve variables such as position of control point microphones, position of phone within the room, direction speaker is facing and presence of user in the signal path. Test results show that our Lok8 (locate mobile positioning system can achieve accuracies better than 10 cm in a real-world environment.

Scattering by bound nucleons

International Nuclear Information System (INIS)

Tezuka, Hirokazu.

1984-10-01

Scattering of a particle by bound nucleons is discussed. Effects of nucleons that are bound in a nucleus are taken as a structure function. The way how to calculate the structure function is given. (author)

Bounds for Asian basket options

Science.gov (United States)

Deelstra, Griselda; Diallo, Ibrahima; Vanmaele, Michèle

2008-09-01

In this paper we propose pricing bounds for European-style discrete arithmetic Asian basket options in a Black and Scholes framework. We start from methods used for basket options and Asian options. First, we use the general approach for deriving upper and lower bounds for stop-loss premia of sums of non-independent random variables as in Kaas et al. [Upper and lower bounds for sums of random variables, Insurance Math. Econom. 27 (2000) 151-168] or Dhaene et al. [The concept of comonotonicity in actuarial science and finance: theory, Insurance Math. Econom. 31(1) (2002) 3-33]. We generalize the methods in Deelstra et al. [Pricing of arithmetic basket options by conditioning, Insurance Math. Econom. 34 (2004) 55-57] and Vanmaele et al. [Bounds for the price of discrete sampled arithmetic Asian options, J. Comput. Appl. Math. 185(1) (2006) 51-90]. Afterwards we show how to derive an analytical closed-form expression for a lower bound in the non-comonotonic case. Finally, we derive upper bounds for Asian basket options by applying techniques as in Thompson [Fast narrow bounds on the value of Asian options, Working Paper, University of Cambridge, 1999] and Lord [Partially exact and bounded approximations for arithmetic Asian options, J. Comput. Finance 10 (2) (2006) 1-52]. Numerical results are included and on the basis of our numerical tests, we explain which method we recommend depending on moneyness and time-to-maturity.

Market access through bound tariffs

DEFF Research Database (Denmark)

Sala, Davide; Yalcin, Erdal; Schröder, Philipp

2010-01-01

on the risk that exporters face in destination markets. The present paper formalizes the underlying interaction of risk, fixed export costs and firms' market entry decisions based on techniques known from the real options literature; doing so we highlight the important role of bound tariffs at the extensive...... margin of trade. We find that bound tariffs are more effective with higher risk destination markets, that a large binding overhang may still command substantial market access, and that reductions in bound tariffs generate effective market access even when bound rates are above current and longterm...

Market Access through Bound Tariffs

DEFF Research Database (Denmark)

Sala, Davide; Schröder, Philipp J.H.; Yalcin, Erdal

on the risk that exporters face in destination markets. The present paper formalizes the underlying interaction of risk, fixed export costs and firms' market entry decisions based on techniques known from the real options literature; doing so we highlight the important role of bound tariffs at the extensive...... margin of trade. We find that bound tariffs are more effective with higher risk destination markets, that a large binding overhang may still command substantial market access, and that reductions in bound tariffs generate effective market access even when bound rates are above current and long...

The Cramér-Rao Bounds and Sensor Selection for Nonlinear Systems with Uncertain Observations.

Science.gov (United States)

Wang, Zhiguo; Shen, Xiaojing; Wang, Ping; Zhu, Yunmin

2018-04-05

This paper considers the problems of the posterior Cramér-Rao bound and sensor selection for multi-sensor nonlinear systems with uncertain observations. In order to effectively overcome the difficulties caused by uncertainty, we investigate two methods to derive the posterior Cramér-Rao bound. The first method is based on the recursive formula of the Cramér-Rao bound and the Gaussian mixture model. Nevertheless, it needs to compute a complex integral based on the joint probability density function of the sensor measurements and the target state. The computation burden of this method is relatively high, especially in large sensor networks. Inspired by the idea of the expectation maximization algorithm, the second method is to introduce some 0-1 latent variables to deal with the Gaussian mixture model. Since the regular condition of the posterior Cramér-Rao bound is unsatisfied for the discrete uncertain system, we use some continuous variables to approximate the discrete latent variables. Then, a new Cramér-Rao bound can be achieved by a limiting process of the Cramér-Rao bound of the continuous system. It avoids the complex integral, which can reduce the computation burden. Based on the new posterior Cramér-Rao bound, the optimal solution of the sensor selection problem can be derived analytically. Thus, it can be used to deal with the sensor selection of a large-scale sensor networks. Two typical numerical examples verify the effectiveness of the proposed methods.

Computationally Efficient Chaotic Spreading Sequence Selection for Asynchronous DS-CDMA

Directory of Open Access Journals (Sweden)

Litviņenko Anna

2017-12-01

Full Text Available The choice of the spreading sequence for asynchronous direct-sequence code-division multiple-access (DS-CDMA systems plays a crucial role for the mitigation of multiple-access interference. Considering the rich dynamics of chaotic sequences, their use for spreading allows overcoming the limitations of the classical spreading sequences. However, to ensure low cross-correlation between the sequences, careful selection must be performed. This paper presents a novel exhaustive search algorithm, which allows finding sets of chaotic spreading sequences of required length with a particularly low mutual cross-correlation. The efficiency of the search is verified by simulations, which show a significant advantage compared to non-selected chaotic sequences. Moreover, the impact of sequence length on the efficiency of the selection is studied.

Determining sociability, social space, and social presence in (a)synchronous collaborative groups.

Science.gov (United States)

Kreijns, Karel; Kirschner, Paul A; Jochems, Wim; Van Buuren, Hans

2004-04-01

The effectiveness of group learning in asynchronous distributed learning groups depends on the social interaction that takes place. This social interaction affects both cognitive and socioemotional processes that take place during learning, group forming, establishment of group structures, and group dynamics. Though now known to be important, this aspect is often ignored, denied or forgotten by educators and researchers who tend to concentrate on cognitive processes and on-task contexts. This "one-sided" educational focus largely determines the set of requirements in the design of computer-supported collaborative learning (CSCL) environments resulting in functional CSCL environments. In contrast, our research is aimed at the design and implementation of sociable CSCL environments which may increase the likelihood that a sound social space will emerge. We use a theoretical framework that is based upon an ecological approach to social interaction, centering on the concept of social affordances, the concept of the sociability of CSCL environments, and social presence theory. The hypothesis is that the higher the sociability, the more likely that social interaction will take place or will increase, and the more likely that this will result in an emerging sound social space. In the present research, the variables of interest are sociability, social space, and social presence. This study deals with the construction and validation of three instruments to determine sociability, social space, and social presence in (a)synchronous collaborating groups. The findings suggest that the instruments have potential to be useful as measures for the respective variables. However, it must be realized that these measures are "first steps."

Realization of station for testing asynchronous three-phase motors

Science.gov (United States)

Wróbel, A.; Surma, W.

2016-08-01

Nowadays, you cannot imagine the construction and operation of machines without the use of electric motors [13-15]. The proposed position is designed to allow testing of asynchronous three-phase motors. The position consists of a tested engine and the engine running as a load, both engines combined with a mechanical clutch [2]. The value of the load is recorded by measuring shaft created with Strain Gauge Bridge. This concept will allow to study the basic parameters of the engines, visualization motor parameters both vector and scalar controlled, during varying load drive system. In addition, registration during the variable physical parameters of the working electric motor, controlled by a frequency converter or controlled by a contactor will be possible. Position is designed as a teaching and research position to characterize the engines. It will be also possible selection of inverter parameters.

A risk standard based on societal cost with bounded consequences

International Nuclear Information System (INIS)

Worledge, D.H.

1982-01-01

A risk standard is proposed that relates the frequency of occurrence of single events to the consequences of the events. Maximum consequences and risk aversion are used to give the cumulative risk curve a shape similar to the results of a risk assessment and to bound the expectation of deaths. Societal costs in terms of deaths are used to fix the parameters of the model together with an approximate comparison with individual risks. The proposed standard is compared with some practical applications of risk assessment to nuclear reactor systems

Holographic Bound in Quantum Field Energy Density and Cosmological Constant

OpenAIRE

Castorina, Paolo

2012-01-01

The cosmological constant problem is reanalyzed by imposing the limitation of the number of degrees of freedom (d.o.f.) due to entropy bounds directly in the calculation of the energy density of a field theory. It is shown that if a quantum field theory has to be consistent with gravity and holography, i.e. with an upper limit of storing information in a given area, the ultraviolet momentum cut-off is not the Planck mass, M_p, as naively expected, but M_p/N_U^(1/4) where N_U is the number of ...

Asynchronous asymmetric form of heterogeneous osteopetrosis: initial case expanded and a new case

International Nuclear Information System (INIS)

Young, L.W.; Lachman, R.S.

2001-01-01

We have discovered additional serial radiographs and clinical information on the initial case of ''regional osteopetrosis tarda'' that has been included in several editions of Caffey's Pediatric X-Ray Diagnosis. A definite second case was found after a search of radiology teaching files of other selected medical centers and the International Skeletal Dysplasia Registry. Analysis of the sequential unusual radiographic findings of the initial case and the equivalent compelling findings of the second case justifies renewed attention to an asynchronous asymmetric form of heterogeneous osteopetrosis. (orig.)

Exploring effectiveness of team communication: Balancing synchronous and asynchronous communication in design teams

DEFF Research Database (Denmark)

den Otter, Ad; Emmitt, Stephen

2007-01-01

Effective teams use a balance of synchronous and asynchronous communication. Team communication is dependent on the communication acts of team members and the ability of managers to facilitate, stimulate and motivate them. Team members from organizations using different information systems tend...... to have different understanding, opinions, and rates of adoption and skills levels regarding specific IT tools. The purpose of this paper is to explore the effective use of tools for communication in design teams and the strategies for the use of specific tools....

Bound and rebound states

International Nuclear Information System (INIS)

Orzalesi, C.A.

1979-01-01

In relativistic quantum theory, bound states generate forces in the crossed channel; such forces can affect the binding and self-consistent solutions should be sought for the bound-state problem. The author investigates how self-consistency can be achieved by successive approximations, in a simple scalar model and with successive relativistic eikonal approximations (EAs). Within the generalized ladder approximation, some exact properties of the resulting ''first generation'' bound states are discussed. The binding energies in this approximation are rather small even for rather large values of the primary coupling constant. The coupling of the constituent particles to the first-generation reggeon is determined by a suitable EA and a new generalized ladder amplitude is constructed with rungs given either by the primary gluons or by the first-generation reggeons. The resulting new (second-generation) bound states are found in a reggeized EA. The size of the corrections to the binding energies due to the rebinding effects is surprisingly large. The procedure is then iterated, so as to find - again in an EA - the third-generation bound states. The procedure is found to be self-consistent already at this stage: the third-generation bound states coincide with those of second generation, and no further rebinding takes place in the higher iterations of the approximation method. Features - good and bad - of the model are discussed, as well as the possible relevance of rebinding mechanisms in hadron dynamics. (author)

An accurate evaluation of the performance of asynchronous DS-CDMA systems with zero-correlation-zone coding in Rayleigh fading

Science.gov (United States)

Walker, Ernest; Chen, Xinjia; Cooper, Reginald L.

2010-04-01

An arbitrarily accurate approach is used to determine the bit-error rate (BER) performance for generalized asynchronous DS-CDMA systems, in Gaussian noise with Raleigh fading. In this paper, and the sequel, new theoretical work has been contributed which substantially enhances existing performance analysis formulations. Major contributions include: substantial computational complexity reduction, including a priori BER accuracy bounding; an analytical approach that facilitates performance evaluation for systems with arbitrary spectral spreading distributions, with non-uniform transmission delay distributions. Using prior results, augmented by these enhancements, a generalized DS-CDMA system model is constructed and used to evaluated the BER performance, in a variety of scenarios. In this paper, the generalized system modeling was used to evaluate the performance of both Walsh- Hadamard (WH) and Walsh-Hadamard-seeded zero-correlation-zone (WH-ZCZ) coding. The selection of these codes was informed by the observation that WH codes contain N spectral spreading values (0 to N - 1), one for each code sequence; while WH-ZCZ codes contain only two spectral spreading values (N/2 - 1,N/2); where N is the sequence length in chips. Since these codes span the spectral spreading range for DS-CDMA coding, by invoking an induction argument, the generalization of the system model is sufficiently supported. The results in this paper, and the sequel, support the claim that an arbitrary accurate performance analysis for DS-CDMA systems can be evaluated over the full range of binary coding, with minimal computational complexity.

A search for deeply-bound kaonic nuclear states at J-PARC

Directory of Open Access Journals (Sweden)

Sakaguchi A.

2010-04-01

Full Text Available The J-PARC E15 experiment will be performed to search for the simplest kaonic nuclear bound state, K− pp, by the in-flight 3He(K−,n reaction. The exclusive measurement can be performed by a simultaneous measurement of the missing mass using the primary neutron and the invariant mass via the expected decay, K− pp → Λp → pπ− p. In this report, an overview of the experiment and the preparation status are presented.

Proximity-Based Asynchronous Messaging Platform for Location-Based Internet of Things Service

Directory of Open Access Journals (Sweden)

Hyeong gon Jo

2016-07-01

Full Text Available The Internet of Things (IoT opens up tremendous opportunities to provide location-based applications. However, despite the services around a user being physically adjacent, common IoT platforms use a centralized structure, like a cloud-computing architecture, which transfers large amounts of data to a central server. This raises problems, such as traffic concentration, long service latency, and high communication cost. In this paper, we propose a physical distance-based asynchronous messaging platform that specializes in processing personalized data and location-based messages. The proposed system disperses traffic using a location-based message-delivery protocol, and has high stability.

Mechanical characteristics of a double-fed machine in asynchronous mode and prospects of its application in the electric drive of mining machines

Science.gov (United States)

Ostrovlyanchik, V. Yu; Popolzin, I. Yu; Kubarev, V. A.; Marshev, D. A.

2017-09-01

The concept of a double-fed machine as an asynchronous motor with a phase rotor and a source of additional voltage is defined. Based on the analysis of a circuit replacing the double-fed machine, an expression is derived relating the moment, slip, amplitude and phase of additional voltage across the rotor. The conditions maximizing the moment with respect to amplitude and phase of additional voltage in the rotor circuit are also obtained, the phase surface of function of machine electromagnetic moment is constructed. The analysis of basic equation of electric drive motion in relation to electric drive of mine hoisting installations and the conclusion about the necessity of work in all four quadrants of coordinate plane “moment-slip” are made. Family of mechanical characteristics is constructed for a double-fed machine and its achievable speed control range in asynchronous mode is determined. Based on the type of mechanical characteristics and the calculated range of speed control, the conclusion is made about the suitability of using a dual-fed asynchronous machine for driving mine mechanisms with a small required speed control range and the need for organizing a combined operating mode for driving mine hoisting installations and other mechanisms with a large speed control range.

Exploring Online Asynchronous Counseling With Tobacco Treatment Specialists in the QUIT-PRIMO and National Dental PBRN HI-QUIT Studies: Who Uses It and What Do They Say?

Science.gov (United States)

Williams, Jessica H; DeLaughter, Kathryn; Volkman, Julie E; Sadasivam, Rajani S; Ray, Midge N; Gilbert, Gregg H; Houston, Thomas K

2018-06-01

To describe the content of messages sent by smokers through asynchronous counseling within a Web-based smoking cessation intervention. Qualitative. National community-based setting of patients who had been engaged by the medical or dental practices at which they attended or via Google advertisements. Adults older than 19 years who were current smokers and interested in quitting. Participants throughout the United States referred to a Web-based cessation intervention by their medical or dental provider or by clicking on a Google advertisement. We conducted a qualitative review of 742 asynchronous counseling messages sent by 270 Web site users. Messages were reviewed, analyzed, and organized into qualitative themes by the investigative team. The asynchronous counseling feature of the intervention was used most frequently by smokers who were white (87%), female (67%), aged 45 to 54 (32%), and who had at least some college-level education (70%). Qualitative analysis yielded 7 basic themes-Talk about the Process of Quitting, Barriers to Quitting, Reasons to Quit, Quit History, Support and Strategies for Quitting, Quitting with Medication, and Quit Progress. The most common theme was Support and Strategies for Quitting with 255 references among all messages. We found rich communication across the spectrum of the quit process, from persons preparing to quit to those who had successfully quit. Asynchronous smoking cessation counseling provides a promising means of social support for smokers during the quit process.

An Asynchronous Recurrent Network of Cellular Automaton-Based Neurons and Its Reproduction of Spiking Neural Network Activities.

Science.gov (United States)

Matsubara, Takashi; Torikai, Hiroyuki

2016-04-01

Modeling and implementation approaches for the reproduction of input-output relationships in biological nervous tissues contribute to the development of engineering and clinical applications. However, because of high nonlinearity, the traditional modeling and implementation approaches encounter difficulties in terms of generalization ability (i.e., performance when reproducing an unknown data set) and computational resources (i.e., computation time and circuit elements). To overcome these difficulties, asynchronous cellular automaton-based neuron (ACAN) models, which are described as special kinds of cellular automata that can be implemented as small asynchronous sequential logic circuits have been proposed. This paper presents a novel type of such ACAN and a theoretical analysis of its excitability. This paper also presents a novel network of such neurons, which can mimic input-output relationships of biological and nonlinear ordinary differential equation model neural networks. Numerical analyses confirm that the presented network has a higher generalization ability than other major modeling and implementation approaches. In addition, Field-Programmable Gate Array-implementations confirm that the presented network requires lower computational resources.

An asynchronous rapid single-flux-quantum demultiplexer based on dual-rail information coding

International Nuclear Information System (INIS)

Dimov, B; Khabipov, M; Balashov, D; Brandt, C M; Buchholz, F-Im; Niemeyer, J; Uhlmann, F H

2005-01-01

We present a novel asynchronous RSFQ demultiplexer based on dual-rail information coding. The electrical scheme of the circuit is designed and optimized to maximize the margins of its elements and to improve the fabrication yield. This optimized scheme has been fabricated with the 4 μm 1 kA cm -2 Nb/Al 2 O 3 -Al/Nb technology of PTB-Braunschweig. The demultiplexer has been tested with different samples of the low-speed incoming data stream and in all cases a correct circuit functionality has been observed

Metabolism of organically bound tritium

International Nuclear Information System (INIS)

Travis, C.C.

1984-01-01

The classic methodology for estimating dose to man from environmental tritium ignores the fact that organically bound tritium in foodstuffs may be directly assimilated in the bound compartment of tissues without previous oxidation. We propose a four-compartment model consisting of a free body water compartment, two organic compartments, and a small, rapidly metabolizing compartment. The utility of this model lies in the ability to input organically bound tritium in foodstuffs directly into the organic compartments of the model. We found that organically bound tritium in foodstuffs can increase cumulative total body dose by a factor of 1.7 to 4.5 times the free body water dose alone, depending on the bound-to-loose ratio of tritium in the diet. Model predictions are compared with empirical measurements of tritium in human urine and tissue samples, and appear to be in close agreement. 10 references, 4 figures, 3 tables

Neural network-based voltage regulator for an isolated asynchronous generator supplying three-phase four-wire loads

Energy Technology Data Exchange (ETDEWEB)

Singh, Bhim; Kasal, Gaurav Kumar [Department of Electrical Engineering, Indian Institute of Technology, Delhi, Hauz-Khas, New Delhi 110016 (India)

2008-06-15

This paper deals with a neural network-based solid state voltage controller for an isolated asynchronous generator (IAG) driven by constant speed prime mover like diesel engine, bio-gas or gasoline engine and supplying three-phase four-wire loads. The proposed control scheme uses an indirect current control and a fast adaptive linear element (adaline) based neural network reference current extractor, which extracts the real positive sequence current component without any phase shift. The neutral current of the source is also compensated by using three single-phase bridge configuration of IGBT (insulated gate bipolar junction transistor) based voltage source converter (VSC) along-with single-phase transformer having self-supported dc bus. The proposed controller provides the functions as a voltage regulator, a harmonic eliminator, a neutral current compensator, and a load balancer. The proposed isolated electrical system with its controller is modeled and simulated in MATLAB along with Simulink and PSB (Power System Block set) toolboxes. The simulated results are presented to demonstrate the capability of an isolated asynchronous generating system driven by a constant speed prime mover for feeding three-phase four-wire loads. (author)

Bound states in string nets

Science.gov (United States)

Schulz, Marc Daniel; Dusuel, Sébastien; Vidal, Julien

2016-11-01

We discuss the emergence of bound states in the low-energy spectrum of the string-net Hamiltonian in the presence of a string tension. In the ladder geometry, we show that a single bound state arises either for a finite tension or in the zero-tension limit depending on the theory considered. In the latter case, we perturbatively compute the binding energy as a function of the total quantum dimension. We also address this issue in the honeycomb lattice where the number of bound states in the topological phase depends on the total quantum dimension. Finally, the internal structure of these bound states is analyzed in the zero-tension limit.

An Autonomous Wireless Sensor Node With Asynchronous ECG Monitoring in 0.18 μ m CMOS.

Science.gov (United States)

Mansano, Andre L; Li, Yongjia; Bagga, Sumit; Serdijn, Wouter A

2016-06-01

The design of a 13.56 MHz/402 MHz autonomous wireless sensor node with asynchronous ECG monitoring for near field communication is presented. The sensor node consists of an RF energy harvester (RFEH), a power management unit, an ECG readout, a data encoder and an RF backscattering transmitter. The energy harvester supplies the system with 1.25 V and offers a power conversion efficiency of 19% from a -13 dBm RF source at 13.56 MHz. The power management unit regulates the output voltage of the RFEH to supply the ECG readout with VECG = 0.95 V and the data encoder with VDE = 0.65 V . The ECG readout comprises an analog front-end (low noise amplifier and programmable voltage to current converter) and an asynchronous level crossing ADC with 8 bits resolution. The ADC output is encoded by a pulse generator that drives a backscattering transmitter at 402 MHz. The total power consumption of the sensor node circuitry is 9.7 μ W for a data rate of 90 kb/s and a heart rate of 70 bpm. The chip has been designed in a 0.18 μm CMOS process and shows superior RF input power sensitivity and lower power consumption when compared to previous works.

Analysis of a hysteresis motor on asynchronous speed using complex permeability

International Nuclear Information System (INIS)

Horii, T.; Yuge, N.; Wakui, G.

1994-01-01

Although hysteresis motors have a comparatively small output for their mechanical dimensions compared with other types of motor, they offer the advantages of extremely low vibration and noise levels, and so are widely used as driving motors in acoustic equipment and uranium gas centrifuges. This paper deals with a method for determining the complex permeability in analysis of hysteresis motors. The method assumes that the magnetic intensity distribution is sinusoidal in the direction of rotation. Analysis of the asynchronous speed of a hysteresis motor is then performed for cylindrical coordinates, using modified Bessel functions. The results of calculations are in good agreement with experimental results, confirming the effectiveness of the proposed model and method for determining the complex permeability

Simulating Quantitative Cellular Responses Using Asynchronous Threshold Boolean Network Ensembles

Directory of Open Access Journals (Sweden)

Shah Imran

2011-07-01

Full Text Available Abstract Background With increasing knowledge about the potential mechanisms underlying cellular functions, it is becoming feasible to predict the response of biological systems to genetic and environmental perturbations. Due to the lack of homogeneity in living tissues it is difficult to estimate the physiological effect of chemicals, including potential toxicity. Here we investigate a biologically motivated model for estimating tissue level responses by aggregating the behavior of a cell population. We assume that the molecular state of individual cells is independently governed by discrete non-deterministic signaling mechanisms. This results in noisy but highly reproducible aggregate level responses that are consistent with experimental data. Results We developed an asynchronous threshold Boolean network simulation algorithm to model signal transduction in a single cell, and then used an ensemble of these models to estimate the aggregate response across a cell population. Using published data, we derived a putative crosstalk network involving growth factors and cytokines - i.e., Epidermal Growth Factor, Insulin, Insulin like Growth Factor Type 1, and Tumor Necrosis Factor α - to describe early signaling events in cell proliferation signal transduction. Reproducibility of the modeling technique across ensembles of Boolean networks representing cell populations is investigated. Furthermore, we compare our simulation results to experimental observations of hepatocytes reported in the literature. Conclusion A systematic analysis of the results following differential stimulation of this model by growth factors and cytokines suggests that: (a using Boolean network ensembles with asynchronous updating provides biologically plausible noisy individual cellular responses with reproducible mean behavior for large cell populations, and (b with sufficient data our model can estimate the response to different concentrations of extracellular ligands. Our

Bounding approaches to system identification

CERN Document Server

Norton, John; Piet-Lahanier, Hélène; Walter, Éric

1996-01-01

In response to the growing interest in bounding error approaches, the editors of this volume offer the first collection of papers to describe advances in techniques and applications of bounding of the parameters, or state variables, of uncertain dynamical systems. Contributors explore the application of the bounding approach as an alternative to the probabilistic analysis of such systems, relating its importance to robust control-system design.

Torque harmonics of an asynchronous motor supplied by a voltage- or current-sourced inverter quasi-square operation

Energy Technology Data Exchange (ETDEWEB)

Kyyrae, J. [Helsinki University of Technology, Institute of Intelligent Power Electronics, Espoo (Finland)

1997-12-31

Voltage- and current-sourced dc-ac converters operating in quasi-square area are compared. Their characteristics are calculated with switching vector, which is space-vector of switching functions. When the load is an asynchronous motor various analytical equations, including torque, are calculated efficiently. Motor current and torque approximations are compared with the simulated ones. (orig.) 6 refs.

Blow Flies Visiting Decaying Alligators: Is Succession Synchronous or Asynchronous?

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Mark P. Nelder

2009-01-01

Full Text Available Succession patterns of adult blow flies (Diptera: Calliphoridae on decaying alligators were investigated in Mobile (Ala, USA during August 2002. The most abundant blow fly species visiting the carcasses were Chrysomya rufifacies (Macquart, Cochliomyia macellaria (Fabricus, Chrysomya megacephala (Fabricus, Phormia regina (Meigen, and Lucilia coeruleiviridis (Macquart. Lucilia coeruleiviridis was collected more often during the early stages of decomposition, followed by Chrysomya spp., Cochliomyia macellaria, and Phormia regina in the later stages. Lucilia coeruleiviridis was the only synchronous blow fly on the three carcasses; other blow fly species exhibited only site-specific synchrony. Using dichotomous correlations and analyses of variance, we demonstrated that blow fly-community succession was asynchronous among three alligators; however, Monte Carlo simulations indicate that there was some degree of synchrony between the carcasses.

High power-efficient asynchronous SAR ADC for IoT devices

Science.gov (United States)

Zhang, Beichen; Yao, Bingbing; Liu, Liyuan; Liu, Jian; Wu, Nanjian

2017-10-01

This paper presents a power-efficient 100-MS/s, 10-bit asynchronous successive approximation register (SAR) ADC. It includes an on-chip reference buffer and the total power dissipation is 6.8 mW. To achieve high performance with high power-efficiency in the proposed ADC, bootstrapped switch, redundancy, set-and-down switching approach, dynamic comparator and dynamic logic techniques are employed. The prototype was fabricated using 65 nm standard CMOS technology. At a 1.2-V supply and 100 MS/s, the ADC achieves an SNDR of 56.2 dB and a SFDR of 65.1 dB. The ADC core consumes only 3.1 mW, resulting in a figure of merit (FOM) of 30.27 fJ/conversionstep and occupies an active area of only 0.009 mm2.

Bounded Intention Planning Revisited

OpenAIRE

Sievers Silvan; Wehrle Martin; Helmert Malte

2014-01-01

Bounded intention planning provides a pruning technique for optimal planning that has been proposed several years ago. In addition partial order reduction techniques based on stubborn sets have recently been investigated for this purpose. In this paper we revisit bounded intention planning in the view of stubborn sets.

Bounded Gaussian process regression

DEFF Research Database (Denmark)

Jensen, Bjørn Sand; Nielsen, Jens Brehm; Larsen, Jan

2013-01-01

We extend the Gaussian process (GP) framework for bounded regression by introducing two bounded likelihood functions that model the noise on the dependent variable explicitly. This is fundamentally different from the implicit noise assumption in the previously suggested warped GP framework. We...... with the proposed explicit noise-model extension....

A symmetric Roos bound for linear codes

NARCIS (Netherlands)

Duursma, I.M.; Pellikaan, G.R.

2006-01-01

The van Lint–Wilson AB-method yields a short proof of the Roos bound for the minimum distance of a cyclic code. We use the AB-method to obtain a different bound for the weights of a linear code. In contrast to the Roos bound, the role of the codes A and B in our bound is symmetric. We use the bound

Bayesian networks and boundedly rational expectations

OpenAIRE

Ran Spiegler

2014-01-01

I present a framework for analyzing decision makers with an imperfect understanding of their environment's correlation structure. The framework borrows the tool of "Bayesian networks", which is ubiquitous in statistics and artificial intelligence. In the model, a decision maker faces an objective multivariate probability distribution (his own action is one of the random variables). He is characterized by a directed acyclic graph over the set of random variables. His subjective belief filters ...

Bounded Tamper Resilience

DEFF Research Database (Denmark)

Damgård, Ivan Bjerre; Faust, Sebastian; Mukherjee, Pratyay

2013-01-01

Related key attacks (RKAs) are powerful cryptanalytic attacks where an adversary can change the secret key and observe the effect of such changes at the output. The state of the art in RKA security protects against an a-priori unbounded number of certain algebraic induced key relations, e.......g., affine functions or polynomials of bounded degree. In this work, we show that it is possible to go beyond the algebraic barrier and achieve security against arbitrary key relations, by restricting the number of tampering queries the adversary is allowed to ask for. The latter restriction is necessary......-protocols (including the Okamoto scheme, for instance) are secure even if the adversary can arbitrarily tamper with the prover’s state a bounded number of times and obtain some bounded amount of leakage. Interestingly, for the Okamoto scheme we can allow also independent tampering with the public parameters. We show...

P2-16: Dual-Bound Model and the Role of Time Bound in Perceptual Decision Making

Directory of Open Access Journals (Sweden)

Daeseob Lim

2012-10-01

Full Text Available The diffusion model (DM encapsulates the dynamics of perceptual decision within a ‘diffusion field’ that is defined by a basis with sensory-evidence (SE and time vectors. At the core of the DM, it assumes that a decision is not made until an evidence particle drifts in the diffusion field and eventually hits one of the two pre-fixed bounds defined in the SE axis. This assumption dictates when and which choice is made by referring to when and which bound will be hit by the evidence particle. What if urgency pressures the decision system to make a choice even when the evidence particle has yet hit the SE bound? Previous modeling attempts at coping with time pressure, despite differences in detail, all manipulated the coordinate of SE bounds. Here, we offer a novel solution by adopting another bound on the time axis. This ‘dual-bound’ model (DBM posits that decisions can also be made when the evidence particle hits a time bound, which is determined on a trial-by-trial basis by a ‘perceived time interval’ – how long the system can stay in the ‘diffusion’ field. The classic single-bound model (SBM exhibited systematic errors in predicting both the reaction time distributions and the time-varying bias in choice. Those errors were not corrected by previously proposed variants of the SBM until the time bound was introduced. The validity of the DBM was further supported by the strong across-individual correlation between observed precision of interval timing and the predicted trial-by-trial variability of the time bound.

A new asynchronous parallel algorithm for inferring large-scale gene regulatory networks.

Directory of Open Access Journals (Sweden)

Xiangyun Xiao

Full Text Available The reconstruction of gene regulatory networks (GRNs from high-throughput experimental data has been considered one of the most important issues in systems biology research. With the development of high-throughput technology and the complexity of biological problems, we need to reconstruct GRNs that contain thousands of genes. However, when many existing algorithms are used to handle these large-scale problems, they will encounter two important issues: low accuracy and high computational cost. To overcome these difficulties, the main goal of this study is to design an effective parallel algorithm to infer large-scale GRNs based on high-performance parallel computing environments. In this study, we proposed a novel asynchronous parallel framework to improve the accuracy and lower the time complexity of large-scale GRN inference by combining splitting technology and ordinary differential equation (ODE-based optimization. The presented algorithm uses the sparsity and modularity of GRNs to split whole large-scale GRNs into many small-scale modular subnetworks. Through the ODE-based optimization of all subnetworks in parallel and their asynchronous communications, we can easily obtain the parameters of the whole network. To test the performance of the proposed approach, we used well-known benchmark datasets from Dialogue for Reverse Engineering Assessments and Methods challenge (DREAM, experimentally determined GRN of Escherichia coli and one published dataset that contains more than 10 thousand genes to compare the proposed approach with several popular algorithms on the same high-performance computing environments in terms of both accuracy and time complexity. The numerical results demonstrate that our parallel algorithm exhibits obvious superiority in inferring large-scale GRNs.

A new asynchronous parallel algorithm for inferring large-scale gene regulatory networks.

Science.gov (United States)

Xiao, Xiangyun; Zhang, Wei; Zou, Xiufen

2015-01-01

The reconstruction of gene regulatory networks (GRNs) from high-throughput experimental data has been considered one of the most important issues in systems biology research. With the development of high-throughput technology and the complexity of biological problems, we need to reconstruct GRNs that contain thousands of genes. However, when many existing algorithms are used to handle these large-scale problems, they will encounter two important issues: low accuracy and high computational cost. To overcome these difficulties, the main goal of this study is to design an effective parallel algorithm to infer large-scale GRNs based on high-performance parallel computing environments. In this study, we proposed a novel asynchronous parallel framework to improve the accuracy and lower the time complexity of large-scale GRN inference by combining splitting technology and ordinary differential equation (ODE)-based optimization. The presented algorithm uses the sparsity and modularity of GRNs to split whole large-scale GRNs into many small-scale modular subnetworks. Through the ODE-based optimization of all subnetworks in parallel and their asynchronous communications, we can easily obtain the parameters of the whole network. To test the performance of the proposed approach, we used well-known benchmark datasets from Dialogue for Reverse Engineering Assessments and Methods challenge (DREAM), experimentally determined GRN of Escherichia coli and one published dataset that contains more than 10 thousand genes to compare the proposed approach with several popular algorithms on the same high-performance computing environments in terms of both accuracy and time complexity. The numerical results demonstrate that our parallel algorithm exhibits obvious superiority in inferring large-scale GRNs.

The use of Facebook for virtual asynchronous focus groups in qualitative research.

Science.gov (United States)

Biedermann, Narelle

2018-02-01

The Internet and the development of more user-engaging applications have opened a whole new world for researchers as a means of recruitment and data collection source. This paper describes the methodological approach of a research study that explored the experiences of Australian military spouses who packed up their family and home to accompany their spouse on an overseas posting. The study used Facebook as a recruitment tool and then as a data source through the conduct of an asynchronous virtual focus group. This paper outlines the advantages and disadvantages of this unique data source as a means of capturing the voices of a hard-to-reach population.

TeBG- and CBG-bound steroid hormones in rabbits are available for influx into uterus in vivo

International Nuclear Information System (INIS)

Chaudhuri, G.; Steingold, K.A.; Pardridge, W.M.; Judd, H.L.

1988-01-01

The metabolic clearance rate (MCR) of gonadal or adrenal steroid hormones in rabbits often does not bear the expected inverse relationship with hormone binding to testosterone-binding globulin (TeBG) or corticosteroid-binding globulin (CBG). This suggests TeBG or CBG may not impede steroid hormone delivery to tissues. The effects of rabbit plasma proteins on the influxes of 3 H-labeled steroids from the circulation into the rabbit uterus were measured in vivo using a tissue sampling single-injection technique. In the absence of plasma proteins, estradiol (E 2 ) and testosterone (T) were freely diffusible through the uterine microvasculature (i.e., extraction >80%). The extractions of dihydrostestosterone (DHT) and corticosterone (B) ranged from 60 to 72%, while that of cortisol (F) was reduced at 40%. Rabbit serum exerted no inhibition of the influxes of the steroids tested. The influxes of T and B greatly exceeded the rates that would be expected if only the free and albumin-bound fractions estimated in vitro were diffusible in vivo. However, the extraction of [ 3 H]corticosteroid-binding globulin or bovine [ 3 H]albumin were low, consistent with little, if any, extravascular uptake of the plasma proteins. The results indicate both albumin-bound and globulin-bound steroid hormone are available for transport into the uterus in the rabbit in vivo without significant exodus of the plasma protein, per se

Distributed PROMPT-LTL Synthesis

Directory of Open Access Journals (Sweden)

Swen Jacobs

2016-09-01

Full Text Available We consider the synthesis of distributed implementations for specifications in Prompt Linear Temporal Logic (PROMPT-LTL, which extends LTL by temporal operators equipped with parameters that bound their scope. For single process synthesis it is well-established that such parametric extensions do not increase worst-case complexities. For synchronous systems, we show that, despite being more powerful, the distributed realizability problem for PROMPT-LTL is not harder than its LTL counterpart. For asynchronous systems we have to consider an assume-guarantee synthesis problem, as we have to express scheduling assumptions. As asynchronous distributed synthesis is already undecidable for LTL, we give a semi-decision procedure for the PROMPT-LTL assume-guarantee synthesis problem based on bounded synthesis.

Demonstration of asynchronous, 40 Gbps x 4-user DPSK-OCDMA transmission using a multi-port encoder/decoder.

Science.gov (United States)

Kataoka, Nobuyuki; Cincotti, Gabriella; Wada, Naoya; Kitayama, Ken-ichi

2011-12-12

We have developed a new 8-chip, 320 Gchip/s encoder/decoder with eight input/output ports, that can be used in 40-Gb/s PON networks. The device has been to multiplex four asynchronous 40 Gb/s users, using DPSK modulation. The transmission over 50 km has been successfully demonstrated for the first time. © 2011 Optical Society of America

Models for light QCD bound states

International Nuclear Information System (INIS)

LaCourse, D.P.

1992-01-01

After a brief overview of Regge, tower, and heavy-quark experimental data, this thesis examines two massless wave equations relevant to quark bound states. We establish general conditions on the Lorentz scalar and Lorentz vector potentials which yield arbitrary leading Regge trajectories for the case of circular classical motion. A semi-classical approximation which includes radial motion reproduces remarkably well the exact solutions. Conditions for tower structure are examined, and found to be incompatible with conditions which give a Nambu stringlike Regge slope. The author then proposes a generalization of the usual potential model of quark bound states in which the confining flux tube is a dynamical object carrying both angular momentum and energy. The Q bar Q-string system with spinless quarks is quantized using an implicit operator technique and the resulting relativistic wave equation is solved. For heavy quarks the usual Schroedinger valence-quark model is recovered. The Regge slope with light quarks agree with the classical rotating-string result and is significantly larger and the effects of short-range forces are also considered. A relativistic generalization of the quantized flux tube model predicts the glueball ground state mass to be √3/α' ≅ 1.9 GeV where α' is the normal Regge slope. The groundstate as well as excited levels like considerably above the expectations of previous models and also above various proposed experimental candidates. The glueball Regge slope is only about three-eighths that for valence quark hadrons. A semi-classical calculation of the Regge slope is in good agreement with a numerically exact value

Instanton bound states in ABJM theory

Energy Technology Data Exchange (ETDEWEB)

Hatsuda, Yasuyuki [DESY Hamburg (Germany). Theory Group; Tokyo Institute of Technology (Japan). Dept. of Physics; Moriyama, Sanefumi [Nagoya Univ. (Japan). Kobayashi Maskawa Inst. and Graduate School of Mathematics; Okuyama, Kazumi [Shinshu Univ., Matsumoto, Nagano (Japan). Dept. of Physics

2013-06-15

The partition function of the ABJM theory receives non-perturbative corrections due to instanton effects. We study these non-perturbative corrections, including bound states of worldsheet instantons and membrane instantons, in the Fermi-gas approach. We require that the total non-perturbative correction should be always finite for arbitrary Chern-Simons level. This finiteness is realized quite non-trivially because each bound state contribution naively diverges at some levels. The poles of each contribution should be canceled out in total. We use this pole cancellation mechanism to find unknown bound state corrections from known ones. We conjecture a general expression of the bound state contribution. Summing up all the bound state contributions, we find that the effect of bound states is simply incorporated into the worldsheet instanton correction by a redefinition of the chemical potential in the Fermi-gas system. Analytic expressions of the 3- and 4-membrane instanton corrections are also proposed.

Identity Presentation: The Construction of Identity in Asynchronous Discussion

Directory of Open Access Journals (Sweden)

Brian Morgan

2008-08-01

Full Text Available This study examines the use of e-mail as a tool for long term discussion between teachers and grade six students. E-mail messages between grade six students and teachers were collected over the course of one academic year. Methods of conversation analysis within a framework of social practice are used to examine the data. While identity is more readily constructed and more fully developed in contexts which allow for physical embodiment such as face-to-face discussion, this analysis found that identity can be constructed in a context that does not provide for the physical embodiment of identity: Identity was constructed using the social, cultural, and technological tools provided and supported by e-mail to develop social practices germane to the e-mail discussion. This study has implications for further understanding the relation between identity, goals, constraints and affordances, and the collaborative creation of social practices in asynchronous computer mediated communication. URN: urn:nbn:de:0114-fqs0803185

Exploring Asynchronous Many-Task Runtime Systems toward Extreme Scales

Energy Technology Data Exchange (ETDEWEB)

Knight, Samuel [O8953; Baker, Gavin Matthew; Gamell, Marc [Rutgers U; Hollman, David [08953; Sjaardema, Gregor [SNL; Kolla, Hemanth [SNL; Teranishi, Keita; Wilke, Jeremiah J; Slattengren, Nicole [SNL; Bennett, Janine Camille

2015-10-01

Major exascale computing reports indicate a number of software challenges to meet the dramatic change of system architectures in near future. While several-orders-of-magnitude increase in parallelism is the most commonly cited of those, hurdles also include performance heterogeneity of compute nodes across the system, increased imbalance between computational capacity and I/O capabilities, frequent system interrupts, and complex hardware architectures. Asynchronous task-parallel programming models show a great promise in addressing these issues, but are not yet fully understood nor developed su ciently for computational science and engineering application codes. We address these knowledge gaps through quantitative and qualitative exploration of leading candidate solutions in the context of engineering applications at Sandia. In this poster, we evaluate MiniAero code ported to three leading candidate programming models (Charm++, Legion and UINTAH) to examine the feasibility of these models that permits insertion of new programming model elements into an existing code base.

FACT. Normalized and asynchronous mirror alignment for Cherenkov telescopes

Energy Technology Data Exchange (ETDEWEB)

Mueller, Sebastian Achim [ETH Zurich (Switzerland); Buss, Jens [TU Dortmund (Germany)

2016-07-01

Imaging Atmospheric Cherenkov Telescopes (IACTs) need fast and large imaging optics to map the faint Cherenkov light emitted in cosmic ray air showers onto their image sensors. Segmented reflectors are inexpensive, lightweight and offer good image quality. However, alignment of the mirror facets remains a challenge. A good alignment is crucial in IACT observations to separate gamma rays from hadronic cosmic rays. We present a star tracking alignment method which is not restricted to clear nights. It normalizes the mirror facet reflections to be independent of the reference star or the cloud coverage. It records asynchronously of the telescope drive which makes the method easy to integrate in existing telescopes. It can be combined with remote facet actuation, but it does not need one to work. Furthermore, it can reconstruct all individual mirror facet point spread functions. We present the method and alignment results on the First Geiger-mode Photo Diode Avalanche Cherenkov Telescope (FACT) on the Canary Island of La Palma, Spain.

Asynchronous, Decentralized DS-CDMA Using Feedback-Controlled Spreading Sequences for Time-Dispersive Channels

Science.gov (United States)

Miyatake, Teruhiko; Chiba, Kazuki; Hamamura, Masanori; Tachikawa, Shin'ichi

We propose a novel asynchronous direct-sequence codedivision multiple access (DS-CDMA) using feedback-controlled spreading sequences (FCSSs) (FCSS/DS-CDMA). At the receiver of FCSS/DS-CDMA, the code-orthogonalizing filter (COF) produces a spreading sequence, and the receiver returns the spreading sequence to the transmitter. Then the transmitter uses the spreading sequence as its updated version. The performance of FCSS/DS-CDMA is evaluated over time-dispersive channels. The results indicate that FCSS/DS-CDMA greatly suppresses both the intersymbol interference (ISI) and multiple access interference (MAI) over time-invariant channels. FCSS/DS-CDMA is applicable to the decentralized multiple access.

Survey is based on Synchronized and Asynchronized Approach of MAC Protocols in WSN

Directory of Open Access Journals (Sweden)

Soni Chaurasia

2010-07-01

Full Text Available A wireless network is made of spatially distributed autonomous devices. These devices are called sensors. The sensor is used for monitoring physical or environmental conditions. The potential application of wireless sensor network is environmental monitoring, healthcare applications and tactical systems. In this paper focus is on the MAC protocol for WSN. Wireless sensor network is deployed for wide range to send and receive data with the help of medium. Here literature survey of MAC protocol based on the synchronized and asynchronized approach is described which is used to meet different objective like access a medium, statistical channel allocation, spectrum utilization

Career Development and Personal Functioning Differences between Work-Bound and Non-Work Bound Students

Science.gov (United States)

Creed, Peter A.; Patton, Wendy; Hood, Michelle

2010-01-01

We surveyed 506 Australian high school students on career development (exploration, planning, job-knowledge, decision-making, indecision), personal functioning (well-being, self-esteem, life satisfaction, school satisfaction) and control variables (parent education, school achievement), and tested differences among work-bound, college-bound and…

Bounds on new contact interactions from future e+e- colliders

International Nuclear Information System (INIS)

Schrempp, B.; Schrempp, F.; Zeppenfeld, D.; Wisconsin Univ., Madison

1988-01-01

A systematic study of the 'reach' for contact interactions as a probe for new physics at future e + e - colliders is performed. A large energy range is considered, from PETRA/PEP energies at the lower end, via the Z 0 peak (SLC/LEP-I) and LEP-II, up to the TeV regime of a potential future linear e + e - collider. Lower bounds on the compositeness scale Λ for leptons are calculated for Bhabha scattering and μ-pair production using realistic assumptions on the expected luminosities and detector performances. The impact of longitudinal and transverse polarization is studied in detail. The 'reach' corresponding to high rates at the Z 0 peak is compared to the one obtained from running at higher energies. At LEP-II energies, a sensitivity to (lepton) substructure at the level of Λ ≅ 10 TeV is to be expected. At a 2 TeV e + e - collider the sensitivity can be as large as 100 TeV. (orig.)

Submaximal Riemann-Roch expected curves and symplectic packing.

Directory of Open Access Journals (Sweden)

Wioletta Syzdek

2007-06-01

Full Text Available We study Riemann-Roch expected curves on $mathbb{P}^1 imes mathbb{P}^1$ in the context of the Nagata-Biran conjecture. This conjecture predicts that for sufficiently large number of points multiple points Seshadri constants of an ample line bundle on algebraic surface are maximal. Biran gives an effective lower bound $N_0$. We construct examples verifying to the effect that the assertions of the Nagata-Biran conjecture can not hold for small number of points. We discuss cases where our construction fails. We observe also that there exists a strong relation between Riemann-Roch expected curves on $mathbb{P}^1 imes mathbb{P}^1$ and the symplectic packing problem. Biran relates the packing problem to the existence of solutions of certain Diophantine equations. We construct such solutions for any ample line bundle on $mathbb{P}^1 imes mathbb{P}^1$ and a relatively smallnumber of points. The solutions geometrically correspond to Riemann-Roch expected curves. Finally we discuss in how far the Biran number $N_0$ is optimal in the case of mathbb{P}^1 imes mathbb{P}^1. In fact we conjecture that it can be replaced by a lower number and we provide evidence justifying this conjecture.

How People Learn in an Asynchronous Online Learning Environment: The Relationships between Graduate Students' Learning Strategies and Learning Satisfaction

Science.gov (United States)

Choi, Beomkyu

2016-01-01

The purpose of this study was to examine the relationships between learners' learning strategies and learning satisfaction in an asynchronous online learning environment. In an attempt to shed some light on how people learn in an online learning environment, one hundred and sixteen graduate students who were taking online learning courses…

Determining Normal-Distribution Tolerance Bounds Graphically

Science.gov (United States)

Mezzacappa, M. A.

1983-01-01

Graphical method requires calculations and table lookup. Distribution established from only three points: mean upper and lower confidence bounds and lower confidence bound of standard deviation. Method requires only few calculations with simple equations. Graphical procedure establishes best-fit line for measured data and bounds for selected confidence level and any distribution percentile.

Techniques for asynchronous and periodically-synchronous coupling of atmosphere and ocean models. Pt. 1. General strategy and application to the cyclo-stationary case

Energy Technology Data Exchange (ETDEWEB)

Sausen, R [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Wessling (Germany). Inst. fuer Physik der Atmosphaere; Voss, R [Deutsches Klimarechenzentrum (DKRZ), Hamburg (Germany)

1995-07-01

Asynchronous and periodically-synchronous schemes for coupling atmosphere and ocean models are presented. The performance of the schemes is tested by simulating the climatic response to a step function forcing and to a gradually increasing forcing with a simple zero-dimensional non-linear energy balance model. Both the initial transient response and the asymptotic approach of the equilibrium state are studied. If no annual cycle is allowed the asynchronous coupling technique proves to be a suitable tool. However, if the annual cycle is retained, the periodically-synchronous coupling technique reproduces the results of the synchronously coupled runs with smaller bias. In this case it is important that the total length of one synchronous period and one ocean only period is not a multiple of 6 months. (orig.)

Asynchronous timing and Doppler recovery in DSP based DPSK modems for fixed and mobile satellite applications

Science.gov (United States)

Koblents, B.; Belanger, M.; Woods, D.; McLane, P. J.

While conventional analog modems employ some kind of clock wave regenerator circuit for synchronous timing recovery, in sampled modem receivers the timing is recovered asynchronously to the incoming data stream, with no adjustment being made to the input sampling rate. All timing corrections are accomplished by digital operations on the sampled data stream, and timing recovery is asynchronous with the uncontrolled, input A/D system. A good timing error measurement algorithm is a zero crossing tracker proposed by Gardner. Digital, speech rate (2400 - 4800 bps) M-PSK modem receivers employing Gardner's zero crossing tracker were implemented and tested and found to achieve BER performance very close to theoretical values on the AWGN channel. Nyguist pulse shaped modem systems with excess bandwidth factors ranging from 100 to 60 percent were considered. We can show that for any symmetric M-PSK signal set Gardner's NDA algorithm is free of pattern jitter for any carrier phase offset for rectangular pulses and for Nyquist pulses having 100 percent excess bandwidth. Also, the Nyquist pulse shaped system is studied on the mobile satellite channel, where Doppler shifts and multipath fading degrade the pi/4-DQPSK signal. Two simple modifications to Gardner's zero crossing tracker enable it to remain useful in the presence of multipath fading.

Extending Landauer's bound from bit erasure to arbitrary computation

Science.gov (United States)

Wolpert, David

The minimal thermodynamic work required to erase a bit, known as Landauer's bound, has been extensively investigated both theoretically and experimentally. However, when viewed as a computation that maps inputs to outputs, bit erasure has a very special property: the output does not depend on the input. Existing analyses of thermodynamics of bit erasure implicitly exploit this property, and thus cannot be directly extended to analyze the computation of arbitrary input-output maps. Here we show how to extend these earlier analyses of bit erasure to analyze the thermodynamics of arbitrary computations. Doing this establishes a formal connection between the thermodynamics of computers and much of theoretical computer science. We use this extension to analyze the thermodynamics of the canonical ``general purpose computer'' considered in computer science theory: a universal Turing machine (UTM). We consider a UTM which maps input programs to output strings, where inputs are drawn from an ensemble of random binary sequences, and prove: i) The minimal work needed by a UTM to run some particular input program X and produce output Y is the Kolmogorov complexity of Y minus the log of the ``algorithmic probability'' of Y. This minimal amount of thermodynamic work has a finite upper bound, which is independent of the output Y, depending only on the details of the UTM. ii) The expected work needed by a UTM to compute some given output Y is infinite. As a corollary, the overall expected work to run a UTM is infinite. iii) The expected work needed by an arbitrary Turing machine T (not necessarily universal) to compute some given output Y can either be infinite or finite, depending on Y and the details of T. To derive these results we must combine ideas from nonequilibrium statistical physics with fundamental results from computer science, such as Levin's coding theorem and other theorems about universal computation. I would like to ackowledge the Santa Fe Institute, Grant No

A solid rotor iron free asynchronous generator for the production of high energy pulses

International Nuclear Information System (INIS)

Rioux, C.; Sultanem, F.

1976-01-01

A rotating machine capable of charging a noncooled magnetic storage coil is described. The rotor of the machine which is formed by metallic cylinder rotating at high speed, also behaves as a flywheel. The stator is composed of a three-phase winding connected to a system of rectifiers and power factor correcting condensers, thus forming an auto excited asynchronous generator. A very high power density is achieved because the machine has non ferrous winding, which permits a magnetic field of a few teslas. The basic machine theory and experimental model built are described