MAI statistics estimation and analysis in a DS-CDMA system

NASA Astrophysics Data System (ADS)

Alami Hassani, A.; Zouak, M.; Mrabti, M.; Abdi, F.

2018-05-01

A primary limitation of Direct Sequence Code Division Multiple Access DS-CDMA link performance and system capacity is multiple access interference (MAI). To examine the performance of CDMA systems in the presence of MAI, i.e., in a multiuser environment, several works assumed that the interference can be approximated by a Gaussian random variable. In this paper, we first develop a new and simple approach to characterize the MAI in a multiuser system. In addition to statistically quantifying the MAI power, the paper also proposes a statistical model for both variance and mean of the MAI for synchronous and asynchronous CDMA transmission. We show that the MAI probability density function (PDF) is Gaussian for the equal-received-energy case and validate it by computer simulations.

Case Study Discussion Experiences of Computer Education and Instructional Technologies Students about Instructional Design on an Asynchronous Environment

ERIC Educational Resources Information Center

Baran, Bahar; Keles, Esra

2011-01-01

The aim of this study is to reveal opinions and experiences of two Computer Education and Instructional Technologies Departments' students about case study discussion method after they discussed in online asynchronous environment about Instructional Design (ID). Totally, 80 second year students, 40 from Dokuz Eylul University and 40 from Karadeniz…

The interference of electronic implants in low frequency electromagnetic fields.

PubMed

Silny, J

2003-04-01

Electronic implants such as cardiac pacemakers or nerve stimulators can be impaired in different ways by amplitude-modulated and even continuous electric or magnetic fields of strong field intensities. For the implant bearer, possible consequences of a temporary electromagnetic interference may range from a harmless impairment of his well-being to a perilous predicament. Electromagnetic interferences in all types of implants cannot be covered here due to their various locations in the body and their different sensing systems. Therefore, this presentation focuses exemplarily on the most frequently used implant, the cardiac pacemaker. In case of an electromagnetic interference the cardiac pacemaker reacts by switching to inhibition mode or to fast asynchronous pacing. At a higher disturbance voltage on the input of the pacemaker, a regular asynchronous pacing is likely to arise. In particular, the first-named interference could be highly dangerous for the pacemaker patient. The interference threshold of cardiac pacemakers depends in a complex way on a number of different factors such as: electromagnetic immunity and adjustment of the pacemaker, the composition of the applied low-frequency fields (only electric or magnetic fields or combinations of both), their frequencies and modulations, the type of pacemaker system (bipolar, unipolar) and its location in the body, as well as the body size and orientation in the field, and last but not least, certain physiological conditions of the patient (e.g. inhalation, exhalation). In extensive laboratory studies we have investigated the interference mechanisms in more than 100 cardiac pacemakers (older types as well as current models) and the resulting worst-case conditions for pacemaker patients in low-frequency electric and magnetic fields. The verification of these results in different practical everyday-life situations, e.g. in the fields of high-voltage overhead lines or those of electronic article surveillance systems is currently in progress. In case of the vertically-oriented electric 50 Hz fields preliminary results show that per 1 kV/m unimpaired electrical field strength (rms) an interference voltage of about 400 microVpp as worst-case could occur at the input of a unipolar ventricularly controlled, left-pectorally implanted cardiac pacemaker. Thus, already a field strength above ca. 5 kV/m could cause an interference with an implanted pacemaker. The magnetic fields induces an electric disturbance voltage at the input of the pacemaker. The body and the pacemaker system compose several induction loops, whose induced voltages rates add or subtract. The effective area of one representing inductive loop ranges from 100 to 221 cm2. For the unfavourable left-pectorally implantated and atrially-controlled pacemaker with a low interference threshold, the interference threshold ranges between 552 and 16 microT (rms) for magnetic fields at frequencies between 10 and 250 Hz. On this basis the occurrence of interferences with implanted pacemakers is possible in everyday-life situations. But experiments demonstrate a low probability of interference of cardiac pacemakers in practical situations. This apparent contradiction can be explained by a very small band of inhibition in most pacemakers and, in comparison with the worst-case, deviating conditions.

Extracting binaural information from simultaneous targets and distractors: Effects of amplitude modulation and asynchronous envelopes

PubMed Central

Stellmack, Mark A.; Byrne, Andrew J.; Viemeister, Neal F.

2010-01-01

When different components of a stimulus carry different binaural information, processing of binaural information in a target component is often affected. The present experiments examine whether such interference is affected by amplitude modulation and the relative phase of modulation of the target and distractors. In all experiments, listeners attempted to discriminate interaural time differences of a target stimulus in the presence of distractor stimuli with ITD=0. In Experiment 1, modulation of the distractors but not the target reduced interference between components. In Experiment 2, synthesized musical notes exhibited little binaural interference when there were slight asynchronies between different streams of notes (31 or 62 ms). The remaining experiments suggested that the reduction in binaural interference in the previous experiments was due neither to the complex spectra of the synthesized notes nor to greater detectability of the target in the presence of modulated distractors. These data suggest that this interference is reduced when components are modulated in ways that result in the target appearing briefly in isolation, not because of segregation cues. These data also suggest that modulation and asynchronies between modulators that might be encountered in real-world listening situations are adequate to reduce binaural interference to inconsequential levels. PMID:20815459

Adaptive digital beamforming for a CDMA mobile communications payload

NASA Technical Reports Server (NTRS)

Munoz-Garcia, Samuel G.; Ruiz, Javier Benedicto

1993-01-01

In recent years, Spread-Spectrum Code Division Multiple Access (CDMA) has become a very popular access scheme for mobile communications due to a variety of reasons: excellent performance in multipath environments, high scope for frequency reuse, graceful degradation near saturation, etc. In this way, a CDMA system can support simultaneous digital communication among a large community of relatively uncoordinated users sharing a given frequency band. Nevertheless, there are also important problems associated with the use of CDMA. First, in a conventional CDMA scheme, the signature sequences of asynchronous users are not orthogonal and, as the number of active users increases, the self-noise generated by the mutual interference between users considerably degrades the performance, particularly in the return link. Furthermore, when there is a large disparity in received powers - due to differences in slant range or atmospheric attenuation - the non-zero cross-correlation between the signals gives rise to the so-called near-far problem. This leads to an inefficient utilization of the satellite resources and, consequently, to a drastic reduction in capacity. Several techniques were proposed to overcome this problem, such as Synchronized CDMA - in which the signature sequences of the different users are quasi-orthogonal - and power control. At the expense of increased network complexity and user coordination, these techniques enable the system capacity to be restored by equitably sharing the satellite resources among the users. An alternative solution is presented based upon the use of time-reference adaptive digital beamforming on board the satellite. This technique enables a high number of independently steered beams to be generated from a single phased array antenna, which automatically track the desired user signal and null the unwanted interference source. In order to use a time-reference adaptive antenna in a communications system, the main challenge is to obtain a reference signal highly correlated with the desired user signal and uncorrelated with the interferences. CDMA lends itself very easily to the generation of such a reference signal, thanks to the a priori knowledge of the user's signature sequence. First, the integration of an adaptive antenna in an asynchronous CDMA system is analyzed. The adaptive antenna system can provide increased interference rejection - much higher than that afforded by the code alone - and, since CDMA is mainly interference limited, any reduction in interference converts directly and linearly into an increase in capacity. Analyses and computer simulations are presented that show how an asynchronous CDMA system incorporating adaptive beamforming can provide at least as much capacity as a synchronous system. More importantly, the proposed concept allows the near-far effect to be mitigated without requiring a tight coordination of the users in terms of transmitted power control or network synchronization. The system is extremely robust to the near-far effect because the signals reaching the satellite from directions other than that of the desired user - which are likely to have different power levels - are adaptively canceled by the antenna. Finally, a payload architecture is presented that illustrates the practical implementation of this concept. This digital payload architecture demonstrates that with the advent of high performance CMOS digital processing, the on-board implementation of complex DSP techniques - in particular Digital Beamforming - has become possible, being most attractive for Mobile Satellite Communications.

Adaptive digital beamforming for a CDMA mobile communications payload

NASA Astrophysics Data System (ADS)

Munoz-Garcia, Samuel G.; Ruiz, Javier Benedicto

In recent years, Spread-Spectrum Code Division Multiple Access (CDMA) has become a very popular access scheme for mobile communications due to a variety of reasons: excellent performance in multipath environments, high scope for frequency reuse, graceful degradation near saturation, etc. In this way, a CDMA system can support simultaneous digital communication among a large community of relatively uncoordinated users sharing a given frequency band. Nevertheless, there are also important problems associated with the use of CDMA. First, in a conventional CDMA scheme, the signature sequences of asynchronous users are not orthogonal and, as the number of active users increases, the self-noise generated by the mutual interference between users considerably degrades the performance, particularly in the return link. Furthermore, when there is a large disparity in received powers - due to differences in slant range or atmospheric attenuation - the non-zero cross-correlation between the signals gives rise to the so-called near-far problem. This leads to an inefficient utilization of the satellite resources and, consequently, to a drastic reduction in capacity. Several techniques were proposed to overcome this problem, such as Synchronized CDMA - in which the signature sequences of the different users are quasi-orthogonal - and power control. At the expense of increased network complexity and user coordination, these techniques enable the system capacity to be restored by equitably sharing the satellite resources among the users. An alternative solution is presented based upon the use of time-reference adaptive digital beamforming on board the satellite. This technique enables a high number of independently steered beams to be generated from a single phased array antenna, which automatically track the desired user signal and null the unwanted interference source. In order to use a time-reference adaptive antenna in a communications system, the main challenge is to obtain a reference signal highly correlated with the desired user signal and uncorrelated with the interferences. CDMA lends itself very easily to the generation of such a reference signal, thanks to the a priori knowledge of the user's signature sequence. First, the integration of an adaptive antenna in an asynchronous CDMA system is analyzed. The adaptive antenna system can provide increased interference rejection - much higher than that afforded by the code alone - and, since CDMA is mainly interference limited, any reduction in interference converts directly and linearly into an increase in capacity. Analyses and computer simulations are presented that show how an asynchronous CDMA system incorporating adaptive beamforming can provide at least as much capacity as a synchronous system. More importantly, the proposed concept allows the near-far effect to be mitigated without requiring a tight coordination of the users in terms of transmitted power control or network synchronization. The system is extremely robust to the near-far effect because the signals reaching the satellite from directions other than that of the desired user - which are likely to have different power levels - are adaptively canceled by the antenna. Finally, a payload architecture is presented that illustrates the practical implementation of this concept.

Evaluation of the effects of electric fields on implanted cardiac pacemakers. Final report

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

Moss, A.J.; Carstensen, E.

1985-02-01

The effects of extra high voltage (EHV) transmission line electric fields on pacemaker function were evaluated in 11 patients with seven different implanted pacemaker models from four manufacturers. Alteration in pacemaker function was demonstrated in five unipolar units (three different models) from two manufacturers during exposure to electric fields ranging from 2 to 9 kV/m, with total body currents from 47 to 175 ..mu..A. These electric fields and body currents are representative of values that can be encountered by individuals standing beneath EHV transmission lines. Transient alterations in pacemaker function observed in this study included inappropriate triggered activity, inhibition ofmore » impulse generation, reduction in rate, and reversion from demand to asynchronous mode. Electromagnetic interference from high voltage transmission lines can induce alterations in pacemaker function in certain designs of these devices. However, pacemaker manufacturers can incorporate appropriate circuits in the pacemaker design to eliminate this problem. 8 references.« less

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

PubMed

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 < 0.001), from a mean score of 18.45 (95% confidence interval [CI] = 17.92 to 18.98) to 21.30 (95% CI = 20.69 to 21.91), a large effect (partial η(2) = 0.19). Posttest scores correlated with ITE scores (r(2) = 0.14, p < 0.001) among pediatric residents. Asynchronous 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.

Optical transmission testing based on asynchronous sampling techniques

NASA Astrophysics Data System (ADS)

Mrozek, T.; Perlicki, K.; Wilczewski, G.

2016-09-01

This paper presents a method of analysis of images obtained with the Asynchronous Delay Tap Sampling technique, which is used for simultaneous monitoring of a number of phenomena in the physical layer of an optical network. This method allows visualization of results in a form of an optical signal's waveform (characteristics depicting phase portraits). Depending on a specific phenomenon being observed (i.e.: chromatic dispersion, polarization mode dispersion and ASE noise), the shape of the waveform changes. Herein presented original waveforms were acquired utilizing the OptSim 4.0 simulation package. After specific simulation testing, the obtained numerical data was transformed into an image form, that was further subjected to the analysis using authors' custom algorithms. These algorithms utilize various pixel operations and creation of reports each image might be characterized with. Each individual report shows the number of black pixels being present in the specific image segment. Afterwards, generated reports are compared with each other, across the original-impaired relationship. The differential report is created which consists of a "binary key" that shows the increase in the number of pixels in each particular segment. The ultimate aim of this work is to find the correlation between the generated binary keys and the analyzed common phenomenon being observed, allowing identification of the type of interference occurring. In the further course of the work it is evitable to determine their respective values. The presented work delivers the first objective - the ability to recognize interference.

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

PubMed

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

PubMed Central

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%. PMID:24955390

The Use of Efficient Broadcast Protocols in Asynchronous Distributed Systems. Ph.D. Thesis

NASA Technical Reports Server (NTRS)

Schmuck, Frank Bernhard

1988-01-01

Reliable broadcast protocols are important tools in distributed and fault-tolerant programming. They are useful for sharing information and for maintaining replicated data in a distributed system. However, a wide range of such protocols has been proposed. These protocols differ in their fault tolerance and delivery ordering characteristics. There is a tradeoff between the cost of a broadcast protocol and how much ordering it provides. It is, therefore, desirable to employ protocols that support only a low degree of ordering whenever possible. This dissertation presents techniques for deciding how strongly ordered a protocol is necessary to solve a given application problem. It is shown that there are two distinct classes of application problems: problems that can be solved with efficient, asynchronous protocols, and problems that require global ordering. The concept of a linearization function that maps partially ordered sets of events to totally ordered histories is introduced. How to construct an asynchronous implementation that solves a given problem if a linearization function for it can be found is shown. It is proved that in general the question of whether a problem has an asynchronous solution is undecidable. Hence there exists no general algorithm that would automatically construct a suitable linearization function for a given problem. Therefore, an important subclass of problems that have certain commutativity properties are considered. Techniques for constructing asynchronous implementations for this class are presented. These techniques are useful for constructing efficient asynchronous implementations for a broad range of practical problems.

Electrical Design and Evaluation of Asynchronous Serial Bus Communication Network of 48 Sensor Platform LSIs with Single-Ended I/O for Integrated MEMS-LSI Sensors.

PubMed

Shao, Chenzhong; Tanaka, Shuji; Nakayama, Takahiro; Hata, Yoshiyuki; Muroyama, Masanori

2018-01-15

For installing many sensors in a limited space with a limited computing resource, the digitization of the sensor output at the site of sensation has advantages such as a small amount of wiring, low signal interference and high scalability. For this purpose, we have developed a dedicated Complementary Metal-Oxide-Semiconductor (CMOS) Large-Scale Integration (LSI) (referred to as "sensor platform LSI") for bus-networked Micro-Electro-Mechanical-Systems (MEMS)-LSI integrated sensors. In this LSI, collision avoidance, adaptation and event-driven functions are simply implemented to relieve data collision and congestion in asynchronous serial bus communication. In this study, we developed a network system with 48 sensor platform LSIs based on Printed Circuit Board (PCB) in a backbone bus topology with the bus length being 2.4 m. We evaluated the serial communication performance when 48 LSIs operated simultaneously with the adaptation function. The number of data packets received from each LSI was almost identical, and the average sampling frequency of 384 capacitance channels (eight for each LSI) was 73.66 Hz.

Effects of optical layer impairments on 2.5 Gb/s optical CDMA transmission.

PubMed

Feng, H; Mendez, A; Heritage, J; Lennon, W

2000-07-03

We conducted a computer simulation study to assess the effects of optical layer impairments on optical CDMA (O-CDMA) transmission of 8 asynchronous users at 2.5 Gb/s each user over a 214-km link. It was found that with group velocity dispersion compensation, two other residual effects, namely, the nonzero chromatic dispersion slope of the single mode fiber (which causes skew) and the non-uniform EDFA gain (which causes interference power level to exceed signal power level of some codes) degrade the signal to multi-access interference (MAI) ratio. In contrast, four wave mixing and modulation due to the Kerr and Raman contributions to the fiber nonlinear refractive index are less important. Current wavelength-division multiplexing (WDM) technologies, including dispersion management, EDFA gain flattening, and 3 rd order dispersion compensation, are sufficient to overcome the impairments to the O-CDMA transmission system that we considered.

High ventricular lead impedance of a DDD pacemaker after cranial magnetic resonance imaging.

PubMed

Baser, Kazim; Guray, Umit; Durukan, Mine; Demirkan, Burcu

2012-09-01

Management of electromagnetic interference in the form of magnetic resonance imaging (MRI) in patients with pacemakers (PMs) may be challenging. Serious consequences, especially in PM-dependent patients, may be encountered. Changes in device programming, asynchronous pacing, heating of the lead tip(s), and increased thresholds or even device dislocation may be experienced. We report of a patient with a DDD PM who underwent an emergent MRI, after which there was an increase in ventricular impedance as well as increased cardiac biomarkers. ©2011, The Authors. Journal compilation ©2012 Wiley Periodicals, Inc.

The effects of nuclear magnetic resonance on patients with cardiac pacemakers

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

Pavlicek, W.; Geisinger, M.; Castle, L.

1983-04-01

The effect of nuclear magnetic resonance (NMR) imaging on six representative cardiac pacemakers was studied. The results indicate that the threshold for initiating the asynchronous mode of a pacemaker is 17 gauss. Radiofrequency levels are present in an NMR unit and may confuse or possibly inhibit demand pacemakers, although sensing circuitry is normally provided with electromagnetic interference discrimination. Time-varying magnetic fields can generate pulse amplitudes and frequencies to mimic cardiac activity. A serious limitation in the possibility of imaging a patient with a pacemaker would be the alteration of normal pulsing parameters due to time-varying magnetic fields.

Student participation and interactivity using asynchronous computer-mediated communication for resolution of an undergraduate capstone management case study.

PubMed

Miller, Paulette J

2012-01-01

Online discussion activities are designed for computer-mediated learning activities in face-to-face, hybrid, and totally online courses. The use of asynchronous computer-mediated communication (A-CMC) coupled with authentic workplace case studies provides students in the protected learning environment with opportunities to practice workplace decision making and communication. In this study, communication behaviors of transmitter and receiver were analyzed to determine participation and interactivity in communication among small-group participants in a health information management capstone management course.

Electrical Design and Evaluation of Asynchronous Serial Bus Communication Network of 48 Sensor Platform LSIs with Single-Ended I/O for Integrated MEMS-LSI Sensors

PubMed Central

Shao, Chenzhong; Tanaka, Shuji; Nakayama, Takahiro; Hata, Yoshiyuki

2018-01-01

For installing many sensors in a limited space with a limited computing resource, the digitization of the sensor output at the site of sensation has advantages such as a small amount of wiring, low signal interference and high scalability. For this purpose, we have developed a dedicated Complementary Metal-Oxide-Semiconductor (CMOS) Large-Scale Integration (LSI) (referred to as “sensor platform LSI”) for bus-networked Micro-Electro-Mechanical-Systems (MEMS)-LSI integrated sensors. In this LSI, collision avoidance, adaptation and event-driven functions are simply implemented to relieve data collision and congestion in asynchronous serial bus communication. In this study, we developed a network system with 48 sensor platform LSIs based on Printed Circuit Board (PCB) in a backbone bus topology with the bus length being 2.4 m. We evaluated the serial communication performance when 48 LSIs operated simultaneously with the adaptation function. The number of data packets received from each LSI was almost identical, and the average sampling frequency of 384 capacitance channels (eight for each LSI) was 73.66 Hz. PMID:29342923

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

PubMed

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.

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

Sadowski, Greg

In one form, a logic circuit includes an asynchronous logic circuit, a synchronous logic circuit, and an interface circuit coupled between the asynchronous logic circuit and the synchronous logic circuit. The asynchronous logic circuit has a plurality of asynchronous outputs for providing a corresponding plurality of asynchronous signals. The synchronous logic circuit has a plurality of synchronous inputs corresponding to the plurality of asynchronous outputs, a stretch input for receiving a stretch signal, and a clock output for providing a clock signal. The synchronous logic circuit provides the clock signal as a periodic signal but prolongs a predetermined state ofmore » the clock signal while the stretch signal is active. The asynchronous interface detects whether metastability could occur when latching any of the plurality of the asynchronous outputs of the asynchronous logic circuit using said clock signal, and activates the stretch signal while the metastability could occur.« less

Distributed parameter estimation in unreliable sensor networks via broadcast gossip algorithms.

PubMed

Wang, Huiwei; Liao, Xiaofeng; Wang, Zidong; Huang, Tingwen; Chen, Guo

2016-01-01

In this paper, we present an asynchronous algorithm to estimate the unknown parameter under an unreliable network which allows new sensors to join and old sensors to leave, and can tolerate link failures. Each sensor has access to partially informative measurements when it is awakened. In addition, the proposed algorithm can avoid the interference among messages and effectively reduce the accumulated measurement and quantization errors. Based on the theory of stochastic approximation, we prove that our proposed algorithm almost surely converges to the unknown parameter. Finally, we present a numerical example to assess the performance and the communication cost of the algorithm. Copyright © 2015 Elsevier Ltd. All rights reserved.

Testing and Performance Analysis of the Multichannel Error Correction Code Decoder

NASA Technical Reports Server (NTRS)

Soni, Nitin J.

1996-01-01

This report provides the test results and performance analysis of the multichannel error correction code decoder (MED) system for a regenerative satellite with asynchronous, frequency-division multiple access (FDMA) uplink channels. It discusses the system performance relative to various critical parameters: the coding length, data pattern, unique word value, unique word threshold, and adjacent-channel interference. Testing was performed under laboratory conditions and used a computer control interface with specifically developed control software to vary these parameters. Needed technologies - the high-speed Bose Chaudhuri-Hocquenghem (BCH) codec from Harris Corporation and the TRW multichannel demultiplexer/demodulator (MCDD) - were fully integrated into the mesh very small aperture terminal (VSAT) onboard processing architecture and were demonstrated.

Maintaining High Assurance in Asynchronous Messaging

DTIC Science & Technology

2015-10-24

Assurance in Asynchronous Messaging Kevin E. Foltz and William R. Simpson Abstract—Asynchronous messaging is the delivery of a message without... integrity , and confidentiality guarantees. End-to-end security for asynchronous messaging must be provided by the asynchronous messaging layer itself... continuing its processing. At the completion of message transmission, the sender does not know when or whether the receiver received it. The message

Motor disorders of the oesophagus in gastro-oesophageal reflux.

PubMed Central

Mahony, M J; Migliavacca, M; Spitz, L; Milla, P J

1988-01-01

Mechanisms of gastro-oesophageal reflux were studied by oesophageal manometry and pH monitoring in 33 children: nine controls, 15 with gastro-oesophageal reflux alone, and nine with reflux oesophagitis. A total of 122 episodes of reflux were analysed in detail: 82 (67%) were synchronous with swallowing and 40 (33%) asynchronous. Infants with trivial symptoms had gastro-oesophageal reflux synchronous with swallowing, whereas those with serious symptoms had slower acid clearance and asynchronous reflux. There were significant differences in lower oesophageal sphincter pressure and amplitude of oesophageal contractions between controls and patients with both gastro-oesophageal reflux and reflux oesophagitis. In reflux oesophagitis there was a decrease in lower oesophageal sphincter pressure and the contractions had a bizarre waveform suggesting a neuropathic process. PMID:3202640

THESEUS: A wavelength division multiplexed/microwave subcarrier multiplexed optical network, its ATM switch applications and device requirements

NASA Astrophysics Data System (ADS)

Xin, Wei

1997-10-01

A Terabit Hybrid Electro-optical /underline[Se]lf- routing Ultrafast Switch (THESEUS) has been proposed. It is a self-routing wavelength division multiplexed (WDM) / microwave subcarrier multiplexed (SCM) asynchronous transfer mode (ATM) switch for the multirate ATM networks. It has potential to be extended to a large ATM switch as 1000 x 1000 without internal blocking. Among the advantages of the hybrid implementation are flexibility in service upgrade, relaxed tolerances on optical filtering, protocol simplification and less processing overhead. For a small ATM switch, the subcarrier can be used as output buffers to solve output contention. A mathematical analysis was conducted to evaluate different buffer configurations. A testbed has been successfully constructed. Multirate binary data streams have been switched through the testbed and error free reception ([<]10-9 bit error rate) has been achieved. A simple, intuitive theoretical model has been developed to describe the heterodyne optical beat interference. A new concept of interference time and interference length has been introduced. An experimental confirmation has been conducted. The experimental results match the model very well. It shows that a large portion of optical bandwidth is wasted due to the beat interference. Based on the model, several improvement approaches have been proposed. The photo-generated carrier lifetime of silicon germanium has been measured using time-resolved reflectivity measurement. Via oxygen ion implantation, the carrier lifetime has been reduced to as short as 1 ps, corresponding to 1 THz of photodetector bandwidth. It has also been shown that copper dopants act as recombination centers in the silicon germanium.

Acceptability of an Asynchronous Learning Forum on Mobile Devices

ERIC Educational Resources Information Center

Chang, Chih-Kai

2010-01-01

Mobile learning has recently become noteworthy because mobile devices have become popular. To construct an asynchronous learning forum on mobile devices is important because an asynchronous learning forum is always an essential part of networked asynchronous distance learning. However, the input interface in handheld learning devices, which is…

The Influence of Asynchronous Video Communication on Learner Social Presence: A Narrative Analysis of Four Cases

ERIC Educational Resources Information Center

Borup, Jered; West, Richard E.; Graham, Charles R.

2013-01-01

Online courses are increasingly using asynchronous video communication. However, little is known about how asynchronous video communication influences students' communication patterns. This study presents four narratives of students with varying characteristics who engaged in asynchronous video communication. The extrovert valued the efficiency of…

Effects of 60-Heartz electric and magnetic fields on implanted cardiac pacemakers. Final report. [Hazards of power transmission line frequencies

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

Bridges, J.E.; Frazier, M.J.

1979-09-01

The effects of 60-Hz electric and magnetic fields of exta-high voltage (EHV) transmission lines on the performance of implanted cardiac pacemakers were studied by: (1) in vitro bench tests of a total of thirteen cardiac pacemakers; (2) in vivo tests of six implanted cardiac pacemakers in baboons; and (3) non-hazardous skin measurement tests on four humans. Analytical methods were developed to predict the thresholds of body current and electric fields capable of affecting normal pacemaker operation in humans. The field strengths calculated to alter implanted pacemaker performance were compared with the range of maximum electric and magnetic field strengths amore » human would normally encounter under transmission lines of various voltages. Results indicate that the electric field or body current necessary to alter the normal operation of pacemakers is highly dependent on the type of pacemaker and the location of the implanted electrodes. However, cardiologists have not so far detected harmful effects of pacemaker reversion to the asynchronous mode in current types of pacemakers and with present methods of implantation. Such interferences can be eliminated by using advanced pacemakers less sensitive to 60-Hz voltages or by using implantation lead arrangements less sensitive to body current.« less

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

PubMed

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.

Pharmacists’ Perception of Synchronous Versus Asynchronous Distance Learning for Continuing Education Programs

PubMed Central

2014-01-01

Objective. 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. Methods. 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. Results. 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. Conclusion. 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. PMID:24558276

Comparing the force ripple during asynchronous and conventional stimulation.

PubMed

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.

Synchronous Office Hours in an Asynchronous Course: Making the Connection

ERIC Educational Resources Information Center

Gibbons-Kunka, Beatrice

2017-01-01

The notion of synchronous office hours in an asynchronous course seems counterintuitive. After all, one of the tenets of asynchronous education is to not require students to be online and participating at any time during the course. Having taught higher education online asynchronous courses for twenty years, the researcher experimented with online…

An epigenetic state associated with areas of gene duplication

PubMed Central

Gimelbrant, Alexander A.; Chess, Andrew

2006-01-01

Asynchronous DNA replication is an epigenetically determined feature found in all cases of monoallelic expression, including genomic imprinting, X-inactivation, and random monoallelic expression of autosomal genes such as immunoglobulins and olfactory receptor genes. Most genes of the latter class were identified in experiments focused on genes functioning in the chemosensory and immune systems. We performed an unbiased survey of asynchronous replication in the mouse genome, excluding known asynchronously replicated genes. Fully 10% (eight of 80) of the genes tested exhibited asynchronous replication. A common feature of the newly identified asynchronously replicated areas is their proximity to areas of tandem gene duplication. Testing of other clustered areas supported the idea that such regions are enriched with asynchronously replicated genes. PMID:16687731

Health economic modeling of the potential cost saving effects of Neurally Adjusted Ventilator Assist.

PubMed

Hjelmgren, Jonas; Bruce Wirta, Sara; Huetson, Pernilla; Myrén, Karl-Johan; Göthberg, Sylvia

2016-02-01

Asynchrony between patient and ventilator breaths is associated with increased duration of mechanical ventilation (MV). Neurally Adjusted Ventilatory Assist (NAVA) controls MV through an esophageal reading of diaphragm electrical activity via a nasogastric tube mounted with electrode rings. NAVA has been shown to decrease asynchrony in comparison to pressure support ventilation (PSV). The objective of this study was to conduct a health economic evaluation of NAVA compared with PSV. We developed a model based on an indirect link between improved synchrony with NAVA versus PSV and fewer days spent on MV in synchronous patients. Unit costs for MV were obtained from the Swedish intensive care unit register, and used in the model along with NAVA-specific costs. The importance of each parameter (proportion of asynchronous patients, costs, and average MV duration) for the overall results was evaluated through sensitivity analyses. Base case results showed that 21% of patients ventilated with NAVA were asynchronous versus 52% of patients receiving PSV. This equals an absolute difference of 31% and an average of 1.7 days less on MV and a total cost saving of US$7886 (including NAVA catheter costs). A breakeven analysis suggested that NAVA was cost effective compared with PSV given an absolute difference in the proportion of asynchronous patients greater than 2.5% (49.5% versus 52% asynchronous patients with NAVA and PSV, respectively). The base case results were stable to changes in parameters, such as difference in asynchrony, duration of ventilation and daily intensive care unit costs. This study showed economically favorable results for NAVA versus PSV. Our results show that only a minor decrease in the proportion of asynchronous patients with NAVA is needed for investments to pay off and generate savings. Future studies need to confirm this result by directly relating improved synchrony to the number of days on MV. © The Author(s), 2015.

A Phenomenological Synapse Model for Asynchronous Neurotransmitter Release

PubMed Central

Wang, Tao; Yin, Luping; Zou, Xiaolong; Shu, Yousheng; Rasch, Malte J.; Wu, Si

2016-01-01

Neurons communicate with each other via synapses. Action potentials cause release of neurotransmitters at the axon terminal. Typically, this neurotransmitter release is tightly time-locked to the arrival of an action potential and is thus called synchronous release. However, neurotransmitter release is stochastic and the rate of release of small quanta of neurotransmitters can be considerably elevated even long after the ceasing of spiking activity, leading to asynchronous release of neurotransmitters. Such asynchronous release varies for tissue and neuron types and has been shown recently to be pronounced in fast-spiking neurons. Notably, it was found that asynchronous release is enhanced in human epileptic tissue implicating a possibly important role in generating abnormal neural activity. Current neural network models for simulating and studying neural activity virtually only consider synchronous release and ignore asynchronous transmitter release. Here, we develop a phenomenological model for asynchronous neurotransmitter release, which, on one hand, captures the fundamental features of the asynchronous release process, and, on the other hand, is simple enough to be incorporated in large-size network simulations. Our proposed model is based on the well-known equations for short-term dynamical synaptic interactions and includes an additional stochastic term for modeling asynchronous release. We use experimental data obtained from inhibitory fast-spiking synapses of human epileptic tissue to fit the model parameters, and demonstrate that our model reproduces the characteristics of realistic asynchronous transmitter release. PMID:26834617

High power-efficient asynchronous SAR ADC for IoT devices

NASA Astrophysics Data System (ADS)

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.

Designing Asynchronous Communication Tools for Optimization of Patient-Clinician Coordination

PubMed Central

Eschler, Jordan; Liu, Leslie S.; Vizer, Lisa M.; McClure, Jennifer B.; Lozano, Paula; Pratt, Wanda; Ralston, James D.

2015-01-01

Asynchronous communication outside the clinical setting has both enriched and complicated patient-clinician interactions. Many patients can now interact with a patient portal 24 hours a day, asking questions of their clinicians via secure message, checking lab results, ordering medication refills, or making appointments. However, the mode of communication (asynchronous) and the nature of the interaction (lacking tone or body language) strip valuable information from each side of patient-clinician asynchronous communication. Using interviews with 34 individuals who actively manage a chronic illness of their own, or for a child or partner, we elicited narratives about patients’ experiences and expectations for using asynchronous communication to address medical issues with their clinicians. Based on these perspectives, we present opportunities for designing asynchronous communication tools to better facilitate understanding of and coordination around care activities between patients and clinicians. PMID:26958188

Space-Time Joint Interference Cancellation Using Fuzzy-Inference-Based Adaptive Filtering Techniques in Frequency-Selective Multipath Channels

NASA Astrophysics Data System (ADS)

Hu, Chia-Chang; Lin, Hsuan-Yu; Chen, Yu-Fan; Wen, Jyh-Horng

2006-12-01

An adaptive minimum mean-square error (MMSE) array receiver based on the fuzzy-logic recursive least-squares (RLS) algorithm is developed for asynchronous DS-CDMA interference suppression in the presence of frequency-selective multipath fading. This receiver employs a fuzzy-logic control mechanism to perform the nonlinear mapping of the squared error and squared error variation, denoted by ([InlineEquation not available: see fulltext.],[InlineEquation not available: see fulltext.]), into a forgetting factor[InlineEquation not available: see fulltext.]. For the real-time applicability, a computationally efficient version of the proposed receiver is derived based on the least-mean-square (LMS) algorithm using the fuzzy-inference-controlled step-size[InlineEquation not available: see fulltext.]. This receiver is capable of providing both fast convergence/tracking capability as well as small steady-state misadjustment as compared with conventional LMS- and RLS-based MMSE DS-CDMA receivers. Simulations show that the fuzzy-logic LMS and RLS algorithms outperform, respectively, other variable step-size LMS (VSS-LMS) and variable forgetting factor RLS (VFF-RLS) algorithms at least 3 dB and 1.5 dB in bit-error-rate (BER) for multipath fading channels.

Asynchronous Video Streaming vs. Synchronous Videoconferencing for Teaching a Pharmacogenetic Pharmacotherapy Course

PubMed Central

2007-01-01

Objectives To compare students' performance and course evaluations for a pharmacogenetic pharmacotherapy course taught by synchronous videoconferencing method via the Internet and for the same course taught via asynchronous video streaming via the Internet. Methods In spring 2005, a pharmacogenetic therapy course was taught to 73 students located on Amarillo, Lubbock, and Dallas campuses using synchronous videoconferencing, and in spring 2006, to 78 students located on the same 3 campuses using asynchronous video streaming. A course evaluation was administered to each group at the end of the courses. Results Students in the asynchronous setting had final course grades of 89% ± 7% compared to the mean final course grade of 87% ± 7% in the synchronous group (p = 0.05). Regardless of which technology was used, average course grades did not differ significantly among the 3 campus sites. Significantly more of the students in the asynchronous setting agreed (57%) with the statement that they could read the lecture notes and absorb the content on their own without attending the class than students in the synchronous class (23%; chi-square test; p < 0.001). Conclusions Students in both asynchronous and synchronous settings performed well. However, students taught using asynchronous videotaped lectures had lower satisfaction with the method of content delivery, and preferred live interactive sessions or a mix of interactive sessions and asynchronous videos over delivery of content using the synchronous or asynchronous method alone. PMID:17429516

"I Totally Agree with You": Gender Interactions in Educational Online Discussion Groups

ERIC Educational Resources Information Center

Guiller, J.; Durndell, A.

2006-01-01

This paper discusses findings from an extensive project examining gender, language and computer-mediated communication (CMC) in the context of undergraduate psychology courses. The contributions of 197 introductory psychology students (148 females, 49 males) participating in asynchronous CMC as part of their course were collated and coded for…

Hybrid WDM/OCDMA for next generation access network

NASA Astrophysics Data System (ADS)

Wang, Xu; Wada, Naoya; Miyazaki, T.; Cincotti, G.; Kitayama, Ken-ichi

2007-11-01

Hybrid wavelength division multiplexing/optical code division multiple access (WDM/OCDMA) passive optical network (PON), where asynchronous OCDMA traffic transmits over WDM network, can be one potential candidate for gigabit-symmetric fiber-to-the-home (FTTH) services. In a cost-effective WDM/OCDMA network, a large scale multi-port encoder/decoder can be employed in the central office, and a low cost encoder/decoder will be used in optical network unit (ONU). The WDM/OCDMA system could be one promising solution to the symmetric high capacity access network with high spectral efficiency, cost effective, good flexibility and enhanced security. Asynchronous WDM/OCDMA systems have been experimentally demonstrated using superstructured fiber Bragg gratings (SSFBG) and muti-port OCDMA en/decoders. The total throughput has reached above Tera-bit/s with spectral efficiency of about 0.41. The key enabling techniques include ultra-long SSFBG, multi-port E/D with high power contrast ratio, optical thresholding, differential phase shift keying modulation with balanced detection, forward error correction, and etc. Using multi-level modulation formats to carry multi-bit information with single pulse, the total capacity and spectral efficiency could be further enhanced.

Building asynchronous geospatial processing workflows with web services

NASA Astrophysics Data System (ADS)

Zhao, Peisheng; Di, Liping; Yu, Genong

2012-02-01

Geoscience research and applications often involve a geospatial processing workflow. This workflow includes a sequence of operations that use a variety of tools to collect, translate, and analyze distributed heterogeneous geospatial data. Asynchronous mechanisms, by which clients initiate a request and then resume their processing without waiting for a response, are very useful for complicated workflows that take a long time to run. Geospatial contents and capabilities are increasingly becoming available online as interoperable Web services. This online availability significantly enhances the ability to use Web service chains to build distributed geospatial processing workflows. This paper focuses on how to orchestrate Web services for implementing asynchronous geospatial processing workflows. The theoretical bases for asynchronous Web services and workflows, including asynchrony patterns and message transmission, are examined to explore different asynchronous approaches to and architecture of workflow code for the support of asynchronous behavior. A sample geospatial processing workflow, issued by the Open Geospatial Consortium (OGC) Web Service, Phase 6 (OWS-6), is provided to illustrate the implementation of asynchronous geospatial processing workflows and the challenges in using Web Services Business Process Execution Language (WS-BPEL) to develop them.

Significance of microbial asynchronous anabolism to soil carbon dynamics driven by litter inputs

PubMed Central

Fan, Zhaosheng; Liang, Chao

2015-01-01

Soil organic carbon (SOC) plays an important role in the global carbon cycle. However, it remains largely unknown how plant litter inputs impact magnitude, composition and source configuration of the SOC stocks over long term through microbial catabolism and anabolism, mostly due to uncoupled research on litter decomposition and SOC formation. This limits our ability to predict soil system responses to changes in land-use and climate. Here, we examine how microbes act as a valve controlling carbon sequestrated from plant litters versus released to the atmosphere in natural ecosystems amended with plant litters varying in quantity and quality. We find that litter quality – not quantity – regulates long-term SOC dynamics under different plausible scenarios. Long-term changes in bulk SOC stock occur only when the quality of carbon inputs causes asynchronous change in a microbial physiological trait, defined as “microbial biosynthesis acceleration” (MBA). This is the first theoretical demonstration that the response of the SOC stocks to litter inputs is critically determined by the microbial physiology. Our work suggests that total SOC at an equilibrium state may be an intrinsic property of a given ecosystem, which ultimately is controlled by the asynchronous MBA between microbial functional groups. PMID:25849864

Significance of microbial asynchronous anabolism to soil carbon dynamics driven by litter inputs

DOE PAGES

Fan, Zhaosheng; Liang, Chao

2015-04-02

Soil organic carbon (SOC) plays an important role in the global carbon cycle. However, it remains largely unknown how plant litter inputs impact magnitude, composition and source configuration of the SOC stocks over long term through microbial catabolism and anabolism, mostly due to uncoupled research on litter decomposition and SOC formation. This limits our ability to predict soil system responses to changes in land-use and climate. Here, we examine how microbes act as a valve controlling carbon sequestrated from plant litters versus released to the atmosphere in natural ecosystems amended with plant litters varying in quantity and quality. We findmore » that litter quality – not quantity – regulates long-term SOC dynamics under different plausible scenarios. Long-term changes in bulk SOC stock occur only when the quality of carbon inputs causes asynchronous change in a microbial physiological trait, defined as ‘‘microbial biosynthesis acceleration’’ (MBA). This is the first theoretical demonstration that the response of the SOC stocks to litter inputs is critically determined by the microbial physiology. Our work suggests that total SOC at an equilibrium state may be an intrinsic property of a given ecosystem, which ultimately is controlled by the asynchronous MBA between microbial functional groups.« less

An Autonomous Wireless Sensor Node With Asynchronous ECG Monitoring in 0.18 μ m CMOS.

PubMed

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.

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

PubMed

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.

Digital Synchronizer without Metastability

NASA Technical Reports Server (NTRS)

Simle, Robert M.; Cavazos, Jose A.

2009-01-01

A proposed design for a digital synchronizing circuit would eliminate metastability that plagues flip-flop circuits in digital input/output interfaces. This metastability is associated with sampling, by use of flip-flops, of an external signal that is asynchronous with a clock signal that drives the flip-flops: it is a temporary flip-flop failure that can occur when a rising or falling edge of an asynchronous signal occurs during the setup and/or hold time of a flip-flop. The proposed design calls for (1) use of a clock frequency greater than the frequency of the asynchronous signal, (2) use of flip-flop asynchronous preset or clear signals for the asynchronous input, (3) use of a clock asynchronous recovery delay with pulse width discriminator, and (4) tying the data inputs to constant logic levels to obtain (5) two half-rate synchronous partial signals - one for the falling and one for the rising edge. Inasmuch as the flip-flop data inputs would be permanently tied to constant logic levels, setup and hold times would not be violated. The half-rate partial signals would be recombined to construct a signal that would replicate the original asynchronous signal at its original rate but would be synchronous with the clock signal.

The Effects of Asynchronous Visual Delays on Simulator Flight Performance and the Development of Simulator Sickness Symptomatology

DTIC Science & Technology

1986-12-26

NAVAL TRAINING SYSTEMS CENTER ORLANDO. FLORIDA IT FILE COPY THE EFFECTS OF ASYNCHRONOUS VISUAL DELAYS ON SIMULATOR FLIGHT PERFORMANCE AND THE...ASYNCHRONOUS VISUAL. DELAYS ON SI.WLATOR FLIGHT PERF OMANCE AND THE DEVELOPMENT OF SIMLATOR SICKNESS SYMPTOMATOLOGY K. C. Uliano, E. Y. Lambert, R. S. Kennedy...ACCESSION NO. N63733N SP-01 0785-7P6 I. 4780 11. TITLE (Include Security Classification) The Effects of Asynchronous Visual Delays on Simulator Flight

Higher Order Thinking in Collaborative Video Annotations: Investigating Discourse Modeling and the Staggering of Learner Participation

ERIC Educational Resources Information Center

Howard, Craig Dennis

2012-01-01

"Collaborative video annotation" (CVA) allows multiple users to annotate video and create a discussion asynchronously. This dissertation investigates 14 small-group CVA discussions held on YouTube in a pre-service teacher education course. Fourteen groups of 6-12 pre-service teachers (141 total) participated. Five of these groups (48…

Cost-analysis of teledentistry in residential aged care facilities.

PubMed

Mariño, Rodrigo; Tonmukayakul, Utsana; Manton, David; Stranieri, Andrew; Clarke, Ken

2016-09-01

The purpose of this research was to conduct a cost-analysis, from a public healthcare perspective, comparing the cost and benefits of face-to-face patient examination assessments conducted by a dentist at a residential aged care facility (RACF) situated in rural areas of the Australian state of Victoria, with two teledentistry approaches utilizing virtual oral examination. The costs associated with implementing and operating the teledentistry approach were identified and measured using 2014 prices in Australian dollars. Costs were measured as direct intervention costs and programme costs. A population of 100 RACF residents was used as a basis to estimate the cost of oral examination and treatment plan development for the traditional face-to-face model vs. two teledentistry models: an asynchronous review and treatment plan preparation; and real-time communication with a remotely located oral health professional. It was estimated that if 100 residents received an asynchronous oral health assessment and treatment plan, the net cost from a healthcare perspective would be AU$32.35 (AU$27.19-AU$38.49) per resident. The total cost of the conventional face-to-face examinations by a dentist would be AU$36.59 ($30.67-AU$42.98) per resident using realistic assumptions. Meanwhile, the total cost of real-time remote oral examination would be AU$41.28 (AU$34.30-AU$48.87) per resident. Teledental asynchronous patient assessments were the lowest cost service model. Access to oral health professionals is generally low in RACFs; however, the real-time consultation could potentially achieve better outcomes due to two-way communication between the nurse and a remote oral health professional via health promotion/disease prevention delivered in conjunction with the oral examination. © The Author(s) 2015.

Modeling and Analysis of Mixed Synchronous/Asynchronous Systems

NASA Technical Reports Server (NTRS)

Driscoll, Kevin R.; Madl. Gabor; Hall, Brendan

2012-01-01

Practical safety-critical distributed systems must integrate safety critical and non-critical data in a common platform. Safety critical systems almost always consist of isochronous components that have synchronous or asynchronous interface with other components. Many of these systems also support a mix of synchronous and asynchronous interfaces. This report presents a study on the modeling and analysis of asynchronous, synchronous, and mixed synchronous/asynchronous systems. We build on the SAE Architecture Analysis and Design Language (AADL) to capture architectures for analysis. We present preliminary work targeted to capture mixed low- and high-criticality data, as well as real-time properties in a common Model of Computation (MoC). An abstract, but representative, test specimen system was created as the system to be modeled.

A novel comparator featured with input data characteristic

NASA Astrophysics Data System (ADS)

Jiang, Xiaobo; Ye, Desheng; Xu, Xiangmin; Zheng, Shuai

2016-03-01

Two types of low-power asynchronous comparators featured with input data statistical characteristic are proposed in this article. The asynchronous ripple comparator stops comparing at the first unequal bit but delivers the result to the least significant bit. The pre-stop asynchronous comparator can completely stop comparing and obtain results immediately. The proposed and contrastive comparators were implemented in SMIC 0.18 μm process with different bit widths. Simulation shows that the proposed pre-stop asynchronous comparator features the lowest power consumption, shortest average propagation delay and highest area efficiency among the comparators. Data path of low-density parity check decoder using the proposed pre-stop asynchronous comparators are most power efficient compared with other data paths with synthesised, clock gating and bitwise competition logic comparators.

Interactional Coherence in Asynchronous Learning Networks: A Rhetorical Approach

ERIC Educational Resources Information Center

Potter, Andrew

2008-01-01

Numerous studies have affirmed the value of asynchronous online communication as a learning resource. Several investigations, however, have indicated that discussions in asynchronous environments are often neither interactive nor coherent. The research reported sought to develop an enhanced understanding of interactional coherence, argumentation,…

Labeled Postings for Asynchronous Interaction

ERIC Educational Resources Information Center

ChanLin, Lih-Juan; Chen, Yong-Ting; Chan, Kung-Chi

2009-01-01

The Internet promotes computer-mediated communications, and so asynchronous learning network systems permit more flexibility in time, space, and interaction than synchronous mode of learning. The key point of asynchronous learning is the materials for web-aided teaching and the flow of knowledge. This research focuses on improving online…

An Asynchronous Augmentation to Traditional Course Delivery.

ERIC Educational Resources Information Center

Wolverton, Marvin L.; Wolverton, Mimi

Asynchronous augmentation facilitates distributed learning, which relies heavily on technology and self-learning. This paper reports the results of delivering a real estate principles course using an asynchronous course delivery format. It highlights one of many ways to enhance learning using technology, and it provides information concerning how…

A Taxonomy of Learning through Asynchronous Discussion

ERIC Educational Resources Information Center

Knowlton, Dave S.

2005-01-01

This article presents a five-tiered taxonomy that describes the nature of participation in, and learning through, asynchronous discussion. The taxonomy is framed by a constructivist view of asynchronous discussion. The five tiers of the taxonomy include the following: (a) passive participation, (b) developmental participation, (c) generative…

Designing Asynchronous Online Discussion Environments: Recent Progress and Possible Future Directions

ERIC Educational Resources Information Center

Gao, Fei; Zhang, Tianyi; Franklin, Teresa

2013-01-01

Asynchronous online discussion environments are important platforms to support learning. Research suggests, however, threaded forums, one of the most popular asynchronous discussion environments, do not often foster productive online discussions naturally. This paper explores how certain properties of threaded forums have affected or constrained…

Integrating Asynchronous Digital Design Into the Computer Engineering Curriculum

ERIC Educational Resources Information Center

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…

Actively Engaging Students in Asynchronous Online Classes. IDEA Paper #64

ERIC Educational Resources Information Center

Riggs, Shannon A.; Linder, Kathryn E.

2016-01-01

Active learning activities and pedagogical strategies can look different in online learning environments, particularly in asynchronous courses when students are not interacting with the instructor, or with each other, in real time. This paper suggests a three-pronged approach for conceptualizing active learning in the online asynchronous class:…

Exploring Asynchronous and Synchronous Tool Use in Online Courses

ERIC Educational Resources Information Center

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…

Teaching Presence and Communication Timeliness in Asynchronous Online Courses

ERIC Educational Resources Information Center

Skramstad, Erik; Schlosser, Charles; Orellana, Anymir

2012-01-01

This study examined student perceptions of teaching presence and communication timeliness in asynchronous online courses. Garrison, Anderson, and Archer's (2000) community of inquiry model provided the framework for the survey research methodology used. Participants were 59 student volunteers taking 1 or more asynchronous online graduate courses.…

Two Studies Examining Argumentation in Asynchronous Computer Mediated Communication

ERIC Educational Resources Information Center

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…

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

ERIC Educational Resources Information Center

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…

Asynchronous Discussion Board Facilitation and Rubric Use in a Blended Learning Environment

ERIC Educational Resources Information Center

Giacumo, Lisa

2012-01-01

The purpose of this study was to investigate the effects of instructor response prompts and rubrics on students' performance in an asynchronous discussion-board assignment, their learning achievement on an objective-type posttest, and their reported satisfaction levels. Researchers who have studied asynchronous computer-mediated student…

Designing Asynchronous, Text-Based Computer Conferences: Ten Research-Based Suggestions

ERIC Educational Resources Information Center

Choitz, Paul; Lee, Doris

2006-01-01

Asynchronous computer conferencing refers to the use of computer software and a network enabling participants to post messages that allow discourse to continue even though interactions may be extended over days and weeks. Asynchronous conferences are time-independent, adapting to multiple time zones and learner schedules. Such activities as…

Asynchronous Learning Forums for Business Acculturation

ERIC Educational Resources Information Center

Pence, Christine Cope; Wulf, Catharina

2009-01-01

The use of IT as a facilitator for student collaboration in higher business education has grown rapidly since 2000. Asynchronous discussion forums are used abundantly for collaborative training purposes and for teaching students business-relevant tools for their future careers. This article presents an analysis of the asynchronous discussion forum…

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

PubMed

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.

Asynchronous glimpsing of speech: Spread of masking and task set-size

PubMed Central

Ozmeral, Erol J.; Buss, Emily; Hall, Joseph W.

2012-01-01

Howard-Jones and Rosen [(1993). J. Acoust. Soc. Am. 93, 2915–2922] investigated the ability to integrate glimpses of speech that are separated in time and frequency using a “checkerboard” masker, with asynchronous amplitude modulation (AM) across frequency. Asynchronous glimpsing was demonstrated only for spectrally wide frequency bands. It is possible that the reduced evidence of spectro-temporal integration with narrower bands was due to spread of masking at the periphery. The present study tested this hypothesis with a dichotic condition, in which the even- and odd-numbered bands of the target speech and asynchronous AM masker were presented to opposite ears, minimizing the deleterious effects of masking spread. For closed-set consonant recognition, thresholds were 5.1–8.5 dB better for dichotic than for monotic asynchronous AM conditions. Results were similar for closed-set word recognition, but for open-set word recognition the benefit of dichotic presentation was more modest and level dependent, consistent with the effects of spread of masking being level dependent. There was greater evidence of asynchronous glimpsing in the open-set than closed-set tasks. Presenting stimuli dichotically supported asynchronous glimpsing with narrower frequency bands than previously shown, though the magnitude of glimpsing was reduced for narrower bandwidths even in some dichotic conditions. PMID:22894234

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

PubMed

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 95.8% enjoyed the flexibility of the method. 39.6% of students preferred asynchronous education for required didactics; 37.5% were neutral; 23% preferred traditional lectures. Asynchronous, computer-based instruction was not equivalent to traditional didactics for novice learners of acute care topics. Interactive, standard didactic education was valuable. Retention rates were similar between instructional methods. Students had mixed attitudes toward asynchronous learning but enjoyed the flexibility. We urge caution in trading in traditional didactic lectures in favor of asynchronous education for novice learners in acute care.

The Effects of Facilitating Feedback on Online Learners' Cognitive Engagement: Evidence from the Asynchronous Online Discussion

ERIC Educational Resources Information Center

Guo, Wenge; Chen, Ye; Lei, Jing; Wen, Yan

2014-01-01

With a large-scale online K-12 teacher professional development course as the research context, this study examined the effects of facilitating feedback on online learners' cognitive engagement using quasi-experiment method. A total of 1,540 discussion messages from 110 learners (65 in the experimental group and 45 in the control group) were both…

Fostering Critical Reflection in a Computer-Based, Asynchronously Delivered Diversity Training Course

ERIC Educational Resources Information Center

Givhan, Shawn T.

2013-01-01

This dissertation study chronicles the creation of a computer-based, asynchronously delivered diversity training course for a state agency. The course format enabled efficient delivery of a mandatory curriculum to the Massachusetts Department of State Police workforce. However, the asynchronous format posed a challenge to achieving the learning…

Anonymity and Motivation in Asynchronous Discussions and L2 Vocabulary Learning

ERIC Educational Resources Information Center

Polat, Nihat; Mancilla, Rae; Mahalingappa, Laura

2013-01-01

This study investigates L2 attainment in asynchronous online environments, specifically possible relationships among anonymity, L2 motivation, participation in discussions, quality of L2 production, and success in L2 vocabulary learning. It examines, in asynchronous discussions, (a) if participation and (b) motivation contribute to L2 vocabulary…

Exploring the Effect of Scripted Roles on Cognitive Presence in Asynchronous Online Discussions

ERIC Educational Resources Information Center

Olesova, Larisa; Slavin, Margaret; Lim, Jieun

2016-01-01

The purpose of this study was to identify the effect of scripted roles on students' level of cognitive presence in asynchronous online threaded discussions. A quantitative content analysis was used to investigate: (1) what level of cognitive presence is achieved by students' assigned roles in asynchronous online discussions; (2) differences…

A Multi-Perspective Investigation into Learners' Interaction in Asynchronous Computer-Mediated Communication (CMC)

ERIC Educational Resources Information Center

Çardak, Çigdem Suzan

2016-01-01

This article focusses on graduate level students' interactions during asynchronous CMC activities of an online course about the teaching profession in Turkey. The instructor of the course designed and facilitated a semester-long asynchronous CMC on forum discussions, and investigated the interaction of learners in multiple perspectives: learners'…

The Negotiation Model in Asynchronous Computer-Mediated Communication (CMC): Negotiation in Task-Based Email Exchanges

ERIC Educational Resources Information Center

Kitade, Keiko

2006-01-01

Based on recent studies, computer-mediated communication (CMC) has been considered a tool to aid in language learning on account of its distinctive interactional features. However, most studies have referred to "synchronous" CMC and neglected to investigate how "asynchronous" CMC contributes to language learning. Asynchronous CMC possesses…

Integrating the Intangibles into Asynchronous Online Instruction: Strategies for Improving Interaction and Social Presence

ERIC Educational Resources Information Center

McGuire, Beverley Foulks

2016-01-01

This paper considers how instructors of asynchronous online courses in the Humanities might integrate intangibles associated with face-to-face instruction into their online environments. It presents a case study of asynchronous online instruction in a philosophy and religion department at a midsize public university in the southeastern United…

Postgraduate Students' Knowledge Construction during Asynchronous Computer Conferences in a Blended Learning Environment: A Malaysian Experience

ERIC Educational Resources Information Center

Kian-Sam, Hong; Lee, Julia Ai Cheng

2008-01-01

Blended learning, using e-learning tools to supplement existing on campus learning, often incorporates asynchronous computer conferencing as a means of augmenting knowledge construction among students. This case study reports findings about levels of knowledge construction amongst adult postgraduate students in six asynchronous computer…

Asynchronous Learning Sources in a High-Tech Organization

ERIC Educational Resources Information Center

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…

Asynchronous reference frame agreement in a quantum network

NASA Astrophysics Data System (ADS)

Islam, Tanvirul; Wehner, Stephanie

2016-03-01

An efficient implementation of many multiparty protocols for quantum networks requires that all the nodes in the network share a common reference frame. Establishing such a reference frame from scratch is especially challenging in an asynchronous network where network links might have arbitrary delays and the nodes do not share synchronised clocks. In this work, we study the problem of establishing a common reference frame in an asynchronous network of n nodes of which at most t are affected by arbitrary unknown error, and the identities of the faulty nodes are not known. We present a protocol that allows all the correctly functioning nodes to agree on a common reference frame as long as the network graph is complete and not more than t\\lt n/4 nodes are faulty. As the protocol is asynchronous, it can be used with some assumptions to synchronise clocks over a network. Also, the protocol has the appealing property that it allows any existing two-node asynchronous protocol for reference frame agreement to be lifted to a robust protocol for an asynchronous quantum network.

Quadriphase DS-CDMA wireless communication systems employing the generalized detector

NASA Astrophysics Data System (ADS)

Tuzlukov, Vyacheslav

2012-05-01

Probability of bit-error Per performance of asynchronous direct-sequence code-division multiple-access (DS-CDMA) wireless communication systems employing the generalized detector (GD) constructed based on the generalized approach to signal processing in noise is analyzed. The effects of pulse shaping, quadriphase or direct sequence quadriphase shift keying (DS-QPSK) spreading, aperiodic spreading sequences are considered in DS-CDMA based on GD and compared with the coherent Neyman-Pearson receiver. An exact Per expression and several approximations: one using the characterristic function method, a simplified expression for the improved Gaussian approximation (IGA) and the simplified improved Gaussian approximation are derived. Under conditions typically satisfied in practice and even with a small number of interferers, the standard Gaussian approximation (SGA) for the multiple-access interference component of the GD statistic and Per performance is shown to be accurate. Moreover, the IGA is shown to reduce to the SGA for pulses with zero excess bandwidth. Second, the GD Per performance of quadriphase DS-CDMA is shown to be superior to that of bi-phase DS-CDMA. Numerical examples by Monte Carlo simulation are presented to illustrate the GD Per performance for square-root raised-cosine pulses and spreading factors of moderate to large values. Also, a superiority of GD employment in CDMA systems over the Neyman-Pearson receiver is demonstrated

Modeling and Analysis of Asynchronous Systems Using SAL and Hybrid SAL

NASA Technical Reports Server (NTRS)

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.

Detection of Failure in Asynchronous Motor Using Soft Computing Method

NASA Astrophysics Data System (ADS)

Vinoth Kumar, K.; Sony, Kevin; Achenkunju John, Alan; Kuriakose, Anto; John, Ano P.

2018-04-01

This paper investigates the stator short winding failure of asynchronous motor also their effects on motor current spectrums. A fuzzy logic approach i.e., model based technique possibly will help to detect the asynchronous motor failure. Actually, fuzzy logic similar to humanoid intelligent methods besides expected linguistic empowering inferences through vague statistics. The dynamic model is technologically advanced for asynchronous motor by means of fuzzy logic classifier towards investigate the stator inter turn failure in addition open phase failure. A hardware implementation was carried out with LabVIEW for the online-monitoring of faults.

Asynchronous discrete control of continuous processes

NASA Astrophysics Data System (ADS)

Kaliski, M. E.; Johnson, T. L.

1984-07-01

The research during this second contract year continued to deal with the development of sound theoretical models for asynchronous systems. Two criteria served to shape the research pursued: the first, that the developed models extend and generalize previously developed research for synchronous discrete control; the second, that the models explicitly address the question of how to incorporate system transition times into themselves. The following sections of this report concisely delineate this year's work. Our original proposal for this research identified four general tasks of investigation: (1.1) Analysis of Qualitative Properties of Asynchronous Hybrid Systems; (1.2) Acceptance and Control for Asynchronous Hybrid Systems.

Pattern of online communication in teaching a blended oral surgery course.

PubMed

Marei, H F; Al-Khalifa, K S

2016-11-01

To explore the factors that might affect the patterns of interaction amongst dental students that can be found in asynchronous online discussion fora. It is a qualitative study that involved the participation of 71 dental students (42 male and 29 female) who belong to one academic year. Students were participated in asynchronous online discussion fora as a part of a blended oral surgery course that involved both face-to-face lecture and an online learning environment using the Blackboard learning management system. Qualitative analysis of students' pattern of discussion was performed using Transcript Analysis Tool. The total number of postings was 410. Sixty-seven of 71 students participated in the discussion by writing posts, whereas all of the students had accessed all of the postings. A positive correlation between imposing vertical questions and the number of non-referential and referential statements was observed. Regarding horizontal questions, a positive correlation was observed with the number of referential statements, whilst there was a negative correlation with the number of non-referential statements. Asynchronous online discussion fora that are integrated as a part of a whole pedagogical practice may provide an opportunity for promoting learning, especially when consideration is given to the structure of problems, timely feedback by tutors and supportive strategies within the discussion threads. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Combining Live Video and Audio Broadcasting, Synchronous Chat, and Asynchronous Open Forum Discussions in Distance Education

ERIC Educational Resources Information Center

Teng, Tian-Lih; Taveras, Marypat

2004-01-01

This article outlines the evolution of a unique distance education program that began as a hybrid--combining face-to-face instruction with asynchronous online teaching--and evolved to become an innovative combination of synchronous education using live streaming video, audio, and chat over the Internet, blended with asynchronous online discussions…

The Development, Validity, and Reliability of Communication Satisfaction in an Online Asynchronous Discussion Scale

ERIC Educational Resources Information Center

Hung, Min-Ling; Chou, Chien

2014-01-01

The purpose of this study was to identify dimensions of students' communication satisfaction in an asynchronous discussion forum. An asynchronous discussion may be defined as text-based human-to-human communication via computer networks that provides a platform for the participants to interact with one another to exchange ideas, insights, and…

Web-based Cases in Teaching and Learning - the Quality of Discussions and a Stage of Perspective Taking in Asynchronous Communication.

ERIC Educational Resources Information Center

Jarvela, Sanna; Hakkinen, Paivi

2002-01-01

Examines the quality of asynchronous interaction in Web-based conferencing among preservice teachers. The study combines asynchronous conferencing with peer and mentor collaboration to electronically apprentice student learning. Results point out different levels of Web-based discussion: higher-level, progressive, and lower-level discussion. A…

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

PubMed Central

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 modules were educational and 95.8% enjoyed the flexibility of the method. 39.6% of students preferred asynchronous education for required didactics; 37.5% were neutral; 23% preferred traditional lectures. Conclusions Asynchronous, computer-based instruction was not equivalent to traditional didactics for novice learners of acute care topics. Interactive, standard didactic education was valuable. Retention rates were similar between instructional methods. Students had mixed attitudes toward asynchronous learning but enjoyed the flexibility. We urge caution in trading in traditional didactic lectures in favor of asynchronous education for novice learners in acute care. PMID:23927420

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

PubMed

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 worsen and become hard to resolve.

Micron MT29F128G08AJAAA 128GB Asynchronous Flash Memory Total Ionizing Dose Characterization Test Report

NASA Technical Reports Server (NTRS)

Campola, Michael; Wyrwas, Edward

2017-01-01

The purpose of this test was to characterize the Micron MT29F128G08AJAAAs parameter degradation for total dose response and to evaluate and compare lot date codes for sensitivity. In the test, the device was exposed to both low dose and high dose rate (HDR) irradiations using gamma radiation. Device parameters such as leakage currents, quantity of upset bits and overall chip and die health were investigated to determine which lot is more robust.

Stand-Alone and Hybrid Positioning Using Asynchronous Pseudolites

PubMed Central

Gioia, Ciro; Borio, Daniele

2015-01-01

global navigation satellite system (GNSS) receivers are usually unable to achieve satisfactory performance in difficult environments, such as open-pit mines, urban canyons and indoors. Pseudolites have the potential to extend GNSS usage and significantly improve receiver performance in such environments by providing additional navigation signals. This also applies to asynchronous pseudolite systems, where different pseudolites operate in an independent way. Asynchronous pseudolite systems require, however, dedicated strategies in order to properly integrate GNSS and pseudolite measurements. In this paper, several asynchronous pseudolite/GNSS integration strategies are considered: loosely- and tightly-coupled approaches are developed and combined with pseudolite proximity and receiver signal strength (RSS)-based positioning. The performance of the approaches proposed has been tested in different scenarios, including static and kinematic conditions. The tests performed demonstrate that the methods developed are effective techniques for integrating heterogeneous measurements from different sources, such as asynchronous pseudolites and GNSS. PMID:25609041

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

PubMed

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.

Hydrodynamic advantages of swimming by salp chains.

PubMed

Sutherland, Kelly R; Weihs, Daniel

2017-08-01

Salps are marine invertebrates comprising multiple jet-propelled swimming units during a colonial life-cycle stage. Using theory, we show that asynchronous swimming with multiple pulsed jets yields substantial hydrodynamic benefit due to the production of steady swimming velocities, which limit drag. Laboratory comparisons of swimming kinematics of aggregate salps ( Salpa fusiformis and Weelia cylindrica ) using high-speed video supported that asynchronous swimming by aggregates results in a smoother velocity profile and showed that this smoother velocity profile is the result of uncoordinated, asynchronous swimming by individual zooids. In situ flow visualizations of W. cylindrica swimming wakes revealed that another consequence of asynchronous swimming is that fluid interactions between jet wakes are minimized. Although the advantages of multi-jet propulsion have been mentioned elsewhere, this is the first time that the theory has been quantified and the role of asynchronous swimming verified using experimental data from the laboratory and the field. © 2017 The Author(s).

Design of pulse waveform for waveform division multiple access UWB wireless communication system.

PubMed

Yin, Zhendong; Wang, Zhirui; Liu, Xiaohui; Wu, Zhilu

2014-01-01

A new multiple access scheme, Waveform Division Multiple Access (WDMA) based on the orthogonal wavelet function, is presented. After studying the correlation properties of different categories of single wavelet functions, the one with the best correlation property will be chosen as the foundation for combined waveform. In the communication system, each user is assigned to different combined orthogonal waveform. Demonstrated by simulation, combined waveform is more suitable than single wavelet function to be a communication medium in WDMA system. Due to the excellent orthogonality, the bit error rate (BER) of multiuser with combined waveforms is so close to that of single user in a synchronous system. That is to say, the multiple access interference (MAI) is almost eliminated. Furthermore, even in an asynchronous system without multiuser detection after matched filters, the result is still pretty ideal and satisfactory by using the third combination mode that will be mentioned in the study.

Performance Analysis of Direct-Sequence Code-Division Multiple-Access Communications with Asymmetric Quadrature Phase-Shift-Keying Modulation

NASA Technical Reports Server (NTRS)

Wang, C.-W.; Stark, W.

2005-01-01

This article considers a quaternary direct-sequence code-division multiple-access (DS-CDMA) communication system with asymmetric quadrature phase-shift-keying (AQPSK) modulation for unequal error protection (UEP) capability. Both time synchronous and asynchronous cases are investigated. An expression for the probability distribution of the multiple-access interference is derived. The exact bit-error performance and the approximate performance using a Gaussian approximation and random signature sequences are evaluated by extending the techniques used for uniform quadrature phase-shift-keying (QPSK) and binary phase-shift-keying (BPSK) DS-CDMA systems. Finally, a general system model with unequal user power and the near-far problem is considered and analyzed. The results show that, for a system with UEP capability, the less protected data bits are more sensitive to the near-far effect that occurs in a multiple-access environment than are the more protected bits.

Volition and eye movements.

PubMed

Nachev, Parashkev; Husain, Masud; Kennard, Christopher

2008-01-01

Although the conceptual distinction between voluntary and automatic acts seems intuitively obvious, its neural basis remains opaque. Assigning volition--or some paraphrase such as action selection--to discrete parts of the brain arguably tells us nothing about what volition actually is in neural terms. Equally, exploring the relative sensitivity of discrete brain areas to manipulations of action choice, including its asymptote--free choice--would only be informative if voluntary processes could thereby be reliably isolated. Unfortunately, such manipulations are subject to ineliminable confounds, such as the complexity of the underlying condition-action associations. Here we propose an adaptation of a classic oculomotor task--saccadic choice with asynchronous targets--where the processes engaged in free choice manifest as interference in the performance of an automatic task, thereby circumventing the difficulties in parameterising volition. We suggest that this task may be useful in probing deficits in voluntary action in pathological states.

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

ERIC Educational Resources Information Center

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…

Differences in Electronic Exchanges in Synchronous and Asynchronous Computer-Mediated Communication: The Effect of Culture as a Mediating Variable

ERIC Educational Resources Information Center

Angeli, Charoula; Schwartz, Neil H.

2016-01-01

Two hundred and eighty undergraduates from universities in two countries were asked to read didactic material, and then think and write about potential solutions to an ill-defined problem. The writing was conducted within a synchronous or asynchronous computer-mediated communication (CMC) environment. Asynchronous CMC took the form of email…

Localized radio frequency communication using asynchronous transfer mode protocol

DOEpatents

Witzke, Edward L [Edgewood, NM; Robertson, Perry J [Albuquerque, NM; Pierson, Lyndon G [Albuquerque, NM

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.

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

PubMed

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.

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

PubMed Central

Ros, Wynand JG; Schrijvers, Guus

2014-01-01

Background 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. Objective 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. Methods 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. Results 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. Conclusions The effect of asynchronous communication is not shown unequivocally in these studies. Patients seem to be interested in using email. Patients are willing to participate and are taking the initiative to discuss health issues with their providers. Additional testing of the effects of asynchronous communication on self-management in chronically ill patients is needed. PMID:24434570

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.

PubMed

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 communication is not shown unequivocally in these studies. Patients seem to be interested in using email. Patients are willing to participate and are taking the initiative to discuss health issues with their providers. Additional testing of the effects of asynchronous communication on self-management in chronically ill patients is needed.

Asynchronous vibration problem of centrifugal compressor

NASA Technical Reports Server (NTRS)

Fujikawa, T.; Ishiguro, N.; Ito, M.

1980-01-01

An unstable asynchronous vibration problem in a high pressure centrifugal compressor and the remedial actions against it are described. Asynchronous vibration of the compressor took place when the discharge pressure (Pd) was increased, after the rotor was already at full speed. The typical spectral data of the shaft vibration indicate that as the pressure Pd increases, pre-unstable vibration appears and becomes larger, and large unstable asynchronous vibration occurs suddenly (Pd = 5.49MPa). A computer program was used which calculated the logarithmic decrement and the damped natural frequency of the rotor bearing systems. The analysis of the log-decrement is concluded to be effective in preventing unstable vibration in both the design stage and remedial actions.

Optimization of parameters of special asynchronous electric drives

NASA Astrophysics Data System (ADS)

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.

Lipemia interferences in routine clinical biochemical tests.

PubMed

Calmarza, Pilar; Cordero, José

2011-01-01

Lipemic specimens are a common and frequent, but yet unresolved problem in clinical chemistry, and may produce significant interferences in the analytical results of different biochemical parameters. The aim of this study was to examine the effect of lipid removal using ultracentrifugation of lipemic samples, on some routine biochemistry parameters. Among all the samples obtained daily in our laboratory, the ones which were visibly muddy were selected and underwent to a process of ultracentrifugation, being determined a variety of biochemical tests before and after ultracentrifugation. A total of 110 samples were studied. We found significant differences in all the parameters studied except for total bilirubin, glucose, gamma-glutamyl transferase (GGT) and aspartate aminotransferase (AST). The greatest differences in the parameters analyzed were found in the concentration of alanine aminotransferase (ALT) (7.36%) and the smallest ones in the concentration of glucose (0.014%). Clinically significant interferences were found for phosphorus, creatinine, total protein and calcium. Lipemia causes clinically significant interferences for phosphorus, creatinine, total protein and calcium measurement and those interferences could be effectively removed by ultracentrifugation.

Asynchronous Communication of TLNS3DMB Boundary Exchange

NASA Technical Reports Server (NTRS)

Hammond, Dana P.

1997-01-01

This paper describes the recognition of implicit serialization due to coarse-grain, synchronous communication and demonstrates the conversion to asynchronous communication for the exchange of boundary condition information in the Thin-Layer Navier Stokes 3-Dimensional Multi Block (TLNS3DMB) code. The implementation details of using asynchronous communication is provided including buffer allocation, message identification, and barrier control. The IBM SP2 was used for the tests presented.

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

PubMed

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.

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

PubMed Central

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

Efficacy of an asynchronous electronic curriculum in emergency medicine education in the United States.

PubMed

Wray, Alisa; Bennett, Kathryn; Boysen-Osborn, Megan; Wiechmann, Warren; Toohey, Shannon

2017-01-01

The aim of this study was to measure the effect of an iPad-based asynchronous curriculum on emergency medicine resident performance on the in-training exam (ITE). We hypothesized that the implementation of an asynchronous curriculum (replacing 1 hour of weekly didactic time) would result in non-inferior ITE scores compared to the historical scores of residents who had participated in the traditional 5-hour weekly didactic curriculum. The study was a retrospective, non-inferiority study. conducted at the University of California, Irvine Emergency Medicine Residency Program. We compared ITE scores from 2012 and 2013, when there were 5 weekly hours of didactic content, with scores from 2014 and 2015, when 1 hour of conference was replaced with asynchro-nous content. Examination results were compared using a non-inferiority data analysis with a 10% margin of difference. Using a non-inferiority test with a 95% confidence interval, there was no difference between the 2 groups (before and after implementation of asynchronous learning), as the confidence interval for the change of the ITE was -3.5 to 2.3 points, whereas the 10% non-inferiority margin was 7.8 points. Replacing 1 hour of didactic conference with asynchronous learning showed no negative impact on resident ITE scores.

Representation and Analysis of Real-Time Control Structures.

DTIC Science & Technology

1980-08-01

external processes which cannot be forced to cooperate with programmed processes through use of a synchronization primitive such as a semaphore [Dijkstre...amounts to each task, but the time slices are synchronized with program execution. The length of the codestrip is determined by the response time...which might be synchronous or asynchronous with respect to the executing task. The notation can represent total and partial orderings among its tasks, and

The pH of chemistry assays plays an important role in monoclonal immunoglobulin interferences.

PubMed

Alberti, Michael O; Drake, Thomas A; Song, Lu

2015-12-01

Immunoglobulin paraproteins can interfere with multiple chemistry assays. We want to investigate the mechanisms of immunoglobulin interference. Serum samples containing paraproteins from the index patient and eight additional patients were used to investigate the interference with the creatinine and total protein assays on the Beckman Coulter AU5400/2700 analyzer, and to determine the effects of pH and ionic strength on the precipitation of different immunoglobulins in these patient samples. The paraprotein interference with the creatinine and total protein assays was caused by the precipitation of IgM paraprotein in the index patient's samples under alkaline assay conditions. At extremely high pH (12-13) and extremely low pH (1-2) and low ionic strength, paraprotein formed large aggregates in samples from the index patient but not from other patients. The pH and ionic strength are the key factors that contribute to protein aggregation and precipitation which interfere with the creatinine and total protein measurements on AU5400/2700. The different amino acid sequence of each monoclonal paraprotein will determine the pH and ionic strength at which the paraprotein will precipitate.

Asynchronous parallel status comparator

DOEpatents

Arnold, Jeffrey W.; Hart, Mark M.

1992-01-01

Apparatus for matching asynchronously received signals and determining whether two or more out of a total number of possible signals match. The apparatus comprises, in one embodiment, an array of sensors positioned in discrete locations and in communication with one or more processors. The processors will receive signals if the sensors detect a change in the variable sensed from a nominal to a special condition and will transmit location information in the form of a digital data set to two or more receivers. The receivers collect, read, latch and acknowledge the data sets and forward them to decoders that produce an output signal for each data set received. The receivers also periodically reset the system following each scan of the sensor array. A comparator then determines if any two or more, as specified by the user, of the output signals corresponds to the same location. A sufficient number of matches produces a system output signal that activates a system to restore the array to its nominal condition.

Asynchronous parallel status comparator

DOEpatents

Arnold, J.W.; Hart, M.M.

1992-12-15

Disclosed is an apparatus for matching asynchronously received signals and determining whether two or more out of a total number of possible signals match. The apparatus comprises, in one embodiment, an array of sensors positioned in discrete locations and in communication with one or more processors. The processors will receive signals if the sensors detect a change in the variable sensed from a nominal to a special condition and will transmit location information in the form of a digital data set to two or more receivers. The receivers collect, read, latch and acknowledge the data sets and forward them to decoders that produce an output signal for each data set received. The receivers also periodically reset the system following each scan of the sensor array. A comparator then determines if any two or more, as specified by the user, of the output signals corresponds to the same location. A sufficient number of matches produces a system output signal that activates a system to restore the array to its nominal condition. 4 figs.

Asynchronous data acquisition and on-the-fly analysis of dose fractionated cryoEM images by UCSFImage

PubMed Central

Li, Xueming; Zheng, Shawn; Agard, David A.; Cheng, Yifan

2015-01-01

Newly developed direct electron detection cameras have a high image output frame rate that enables recording dose fractionated image stacks of frozen hydrated biological samples by electron cryomicroscopy (cryoEM). Such novel image acquisition schemes provide opportunities to analyze cryoEM data in ways that were previously impossible. The file size of a dose fractionated image stack is 20 ~ 60 times larger than that of a single image. Thus, efficient data acquisition and on-the-fly analysis of a large number of dose-fractionated image stacks become a serious challenge to any cryoEM data acquisition system. We have developed a computer-assisted system, named UCSFImage4, for semi-automated cryo-EM image acquisition that implements an asynchronous data acquisition scheme. This facilitates efficient acquisition, on-the-fly motion correction, and CTF analysis of dose fractionated image stacks with a total time of ~60 seconds/exposure. Here we report the technical details and configuration of this system. PMID:26370395

Asynchronous networks: modularization of dynamics theorem

NASA Astrophysics Data System (ADS)

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.

Distributed Data-aggregation Consensus for Sensor Networks: Relaxation of Consensus Concept and Convergence Property

DTIC Science & Technology

2014-08-01

consensus algorithm called randomized gossip is more suitable [7, 8]. In asynchronous randomized gossip algorithms, pairs of neighboring nodes exchange...messages and perform updates in an asynchronous and unattended manner, and they also 1 The class of broadcast gossip algorithms [9, 10, 11, 12] are...dynamics [2] and asynchronous pairwise randomized gossip [7, 8], broadcast gossip algorithms do not require that nodes know the identities of their

Simulating fail-stop in asynchronous distributed systems

NASA Technical Reports Server (NTRS)

Sabel, Laura; Marzullo, Keith

1994-01-01

The fail-stop failure model appears frequently in the distributed systems literature. However, in an asynchronous distributed system, the fail-stop model cannot be implemented. In particular, it is impossible to reliably detect crash failures in an asynchronous system. In this paper, we show that it is possible to specify and implement a failure model that is indistinguishable from the fail-stop model from the point of view of any process within an asynchronous system. We give necessary conditions for a failure model to be indistinguishable from the fail-stop model, and derive lower bounds on the amount of process replication needed to implement such a failure model. We present a simple one-round protocol for implementing one such failure model, which we call simulated fail-stop.

Asynchronous Video Interviewing as a New Technology in Personnel Selection: The Applicant’s Point of View

PubMed Central

Brenner, Falko S.; Ortner, Tuulia M.; Fay, Doris

2016-01-01

The present study aimed to integrate findings from technology acceptance research with research on applicant reactions to new technology for the emerging selection procedure of asynchronous video interviewing. One hundred six volunteers experienced asynchronous video interviewing and filled out several questionnaires including one on the applicants’ personalities. In line with previous technology acceptance research, the data revealed that perceived usefulness and perceived ease of use predicted attitudes toward asynchronous video interviewing. Furthermore, openness revealed to moderate the relation between perceived usefulness and attitudes toward this particular selection technology. No significant effects emerged for computer self-efficacy, job interview self-efficacy, extraversion, neuroticism, and conscientiousness. Theoretical and practical implications are discussed. PMID:27378969

Network evolution induced by asynchronous stimuli through spike-timing-dependent plasticity.

PubMed

Yuan, Wu-Jie; Zhou, Jian-Fang; Zhou, Changsong

2013-01-01

In sensory neural system, external asynchronous stimuli play an important role in perceptual learning, associative memory and map development. However, the organization of structure and dynamics of neural networks induced by external asynchronous stimuli are not well understood. Spike-timing-dependent plasticity (STDP) is a typical synaptic plasticity that has been extensively found in the sensory systems and that has received much theoretical attention. This synaptic plasticity is highly sensitive to correlations between pre- and postsynaptic firings. Thus, STDP is expected to play an important role in response to external asynchronous stimuli, which can induce segregative pre- and postsynaptic firings. In this paper, we study the impact of external asynchronous stimuli on the organization of structure and dynamics of neural networks through STDP. We construct a two-dimensional spatial neural network model with local connectivity and sparseness, and use external currents to stimulate alternately on different spatial layers. The adopted external currents imposed alternately on spatial layers can be here regarded as external asynchronous stimuli. Through extensive numerical simulations, we focus on the effects of stimulus number and inter-stimulus timing on synaptic connecting weights and the property of propagation dynamics in the resulting network structure. Interestingly, the resulting feedforward structure induced by stimulus-dependent asynchronous firings and its propagation dynamics reflect both the underlying property of STDP. The results imply a possible important role of STDP in generating feedforward structure and collective propagation activity required for experience-dependent map plasticity in developing in vivo sensory pathways and cortices. The relevance of the results to cue-triggered recall of learned temporal sequences, an important cognitive function, is briefly discussed as well. Furthermore, this finding suggests a potential application for examining STDP by measuring neural population activity in a cultured neural network.

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

NASA Astrophysics Data System (ADS)

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 compose asynchronous GSO workflows. Most importantly, it provides better support for locating and diagnosing potential exceptions.

Asynchronous collision integrators: Explicit treatment of unilateral contact with friction and nodal restraints

PubMed Central

Wolff, Sebastian; Bucher, Christian

2013-01-01

This article presents asynchronous collision integrators and a simple asynchronous method treating nodal restraints. Asynchronous discretizations allow individual time step sizes for each spatial region, improving the efficiency of explicit time stepping for finite element meshes with heterogeneous element sizes. The article first introduces asynchronous variational integration being expressed by drift and kick operators. Linear nodal restraint conditions are solved by a simple projection of the forces that is shown to be equivalent to RATTLE. Unilateral contact is solved by an asynchronous variant of decomposition contact response. Therein, velocities are modified avoiding penetrations. Although decomposition contact response is solving a large system of linear equations (being critical for the numerical efficiency of explicit time stepping schemes) and is needing special treatment regarding overconstraint and linear dependency of the contact constraints (for example from double-sided node-to-surface contact or self-contact), the asynchronous strategy handles these situations efficiently and robust. Only a single constraint involving a very small number of degrees of freedom is considered at once leading to a very efficient solution. The treatment of friction is exemplified for the Coulomb model. Special care needs the contact of nodes that are subject to restraints. Together with the aforementioned projection for restraints, a novel efficient solution scheme can be presented. The collision integrator does not influence the critical time step. Hence, the time step can be chosen independently from the underlying time-stepping scheme. The time step may be fixed or time-adaptive. New demands on global collision detection are discussed exemplified by position codes and node-to-segment integration. Numerical examples illustrate convergence and efficiency of the new contact algorithm. Copyright © 2013 The Authors. International Journal for Numerical Methods in Engineering published by John Wiley & Sons, Ltd. PMID:23970806

Within-female plasticity in sex allocation is associated with a behavioural polyphenism in house wrens.

PubMed

Bowers, E K; Thompson, C F; Sakaluk, S K

2016-03-01

Sex allocation theory assumes individual plasticity in maternal strategies, but few studies have investigated within-individual changes across environments. In house wrens, differences between nests in the degree of hatching synchrony of eggs represent a behavioural polyphenism in females, and its expression varies with seasonal changes in the environment. Between-nest differences in hatching asynchrony also create different environments for offspring, and sons are more strongly affected than daughters by sibling competition when hatching occurs asynchronously over several days. Here, we examined variation in hatching asynchrony and sex allocation, and its consequences for offspring fitness. The number and condition of fledglings declined seasonally, and the frequency of asynchronous hatching increased. In broods hatched asynchronously, sons, which are over-represented in the earlier-laid eggs, were in better condition than daughters, which are over-represented in the later-laid eggs. Nonetheless, asynchronous broods were more productive later within seasons. The proportion of sons in asynchronous broods increased seasonally, whereas there was a seasonal increase in the production of daughters by mothers hatching their eggs synchronously, which was characterized by within-female changes in offspring sex and not by sex-biased mortality. As adults, sons from asynchronous broods were in better condition and produced more broods of their own than males from synchronous broods, and both males and females from asynchronous broods had higher lifetime reproductive success than those from synchronous broods. In conclusion, hatching patterns are under maternal control, representing distinct strategies for allocating offspring within broods, and are associated with offspring sex ratios and differences in offspring reproductive success. © 2015 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2015 European Society For Evolutionary Biology.

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

PubMed

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 Binary Array Asynchronous Sorting Algorithm with Using Petri Nets

NASA Astrophysics Data System (ADS)

Voevoda, A. A.; Romannikov, D. O.

2017-01-01

Nowadays the tasks of computations speed-up and/or their optimization are actual. Among the approaches on how to solve these tasks, a method applying approaches of parallelization and asynchronization to a sorting algorithm is considered in the paper. The sorting methods are ones of elementary methods and they are used in a huge amount of different applications. In the paper, we offer a method of an array sorting that based on a division into a set of independent adjacent pairs of numbers and their parallel and asynchronous comparison. And this one distinguishes the offered method from the traditional sorting algorithms (like quick sorting, merge sorting, insertion sorting and others). The algorithm is implemented with the use of Petri nets, like the most suitable tool for an asynchronous systems description.

A comparison of reliability of soil Cd determination by standard spectrometric methods

PubMed Central

McBride, M.B.

2015-01-01

Inductively coupled plasma emission spectrometry (ICP-OES) is the most common method for determination of soil Cd, yet spectral and matrix interferences affect measurements at the available analytical wavelengths for this metal. This study evaluated the severity of the interference over a range of total soil Cd by comparing ICP-OES and ICP-MS measurements of Cd in acid digests. ICP-OES using the emission at 226.5 nm generally unable to quantify soil Cd at low (near-background) levels, and gave unreliable values compared to ICP-MS. Using the line at 228.nm, a marked positive bias in Cd measurement (relative to the 226.5 nm measurement) was attributable to As interference even at soil As concentrations below 10 mg/kg. This spectral interference in ICP-OES was severe in As-contaminated orchard soils, giving a false value for soil total Cd near 2 mg kg−1 when soil As was 100–150 mg kg−1. In attempting to avoid these ICP emission-specific interferences, we evaluated a method to estimate total soil Cd using 1 M HNO3 extraction followed by determination of Cd by flame atomic absorption (FAA), either with or without pre-concentration of Cd using an Aliquat-heptanone extractant. The 1 M HNO3 extracted an average of 82% of total soil Cd. The FAA method had no significant interferences, and estimated the total Cd concentrations in all soils tested with acceptable accuracy. For Cd-contaminated soils, the Aliquat-heptanone pre-concentration step was not necessary, as FAA sensitivity was adequate for quantification of extractable soil Cd and reliable estimation of total soil Cd. PMID:22031569

Destructive interference between electric and toroidal dipole moments in TiO2 cylinders and frustums with coaxial voids

NASA Astrophysics Data System (ADS)

Terekhov, P. D.; Baryshnikova, K. V.; Evlyukhin, A. B.; Shalin, A. S.

2017-11-01

We demonstrate numerically the possibility of multipole interference in the TiO2 (titanium dioxide) microcylinders and microfrustums in the wavelength range 210-300 μm. Resonantly strong destructive interference between toroidal and electric dipole contributions to the scattered field is achieved by a geometry tuning. The toroidal and electric dipole mode overlapping at the resonant wavelength with almost total suppression of the total electric dipole moment is achieved.

Interpolation algorithm for asynchronous ADC-data

NASA Astrophysics Data System (ADS)

Bramburger, Stefan; Zinke, Benny; Killat, Dirk

2017-09-01

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.

Application of intelligent soft start in asynchronous motor

NASA Astrophysics Data System (ADS)

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.

[Haemolysis and turbidity influence on three analysis methods of quantitative determination of total and conjugated bilirubin on ADVIA 1650].

PubMed

Gobert De Paepe, E; Munteanu, G; Schischmanoff, P O; Porquet, D

2008-01-01

Plasma bilirubin testing is crucial to prevent the occurrence of neonatal kernicterus. Haemolysis may occur during sampling and interfere with bilirubin determination. Moreover, lipidic infusions may induce plasma lipemia and also interfere with bilirubin measurement. We evaluated the interference of haemolysis and lipemia with three methods of total and direct bilirubin measurement adaptated on an Advia 1650 analyser (Siemens Medical Solutions Diagnostics) : Synermed (Sofibel), Bilirubin 2 (Siemens) and Bilirubin Auto FS (Diasys). The measurement of total bilirubin was little affected by haemolysis with all three methods. The Bilirubin 2 (Siemens) method was the less sensitive to haemolysis even at low bilirubin levels. The measurement of conjugated bilirubin was significantly altered by low heamoglobin concentrations for Bilirubin Auto FS(R) (30 microM or 0,192 g/100 mL haemoglobin) and for Synermed (60 microM or 0,484 g/100 mL haemoglobin). In marked contrast, we found no haemoglobin interference with the Direct Bilirubin 2 reagent which complied with the method validation criteria from the French Society for Biological Chemistry. The lipemia up to 2 g/L of Ivelip did not affect neither the measurement of total bilirubin for all three methods nor the measurement of conjugated bilirubin with the Diasys and Siemens reagents. However, we observed a strong interference starting at 0,5 g/L of Ivelip with the Synermed reagent. Our data suggest that both Siemens and Diasys methods allow to measure accurately total and conjugated bilirubin in hemolytic and lipemic samples, nevertheless, the Siemens methodology is less affected by these interferences.

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

NASA Astrophysics Data System (ADS)

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.

Distributed asynchronous microprocessor architectures in fault tolerant integrated flight systems

NASA Technical Reports Server (NTRS)

Dunn, W. R.

1983-01-01

The paper discusses the implementation of fault tolerant digital flight control and navigation systems for rotorcraft application. It is shown that in implementing fault tolerance at the systems level using advanced LSI/VLSI technology, aircraft physical layout and flight systems requirements tend to define a system architecture of distributed, asynchronous microprocessors in which fault tolerance can be achieved locally through hardware redundancy and/or globally through application of analytical redundancy. The effects of asynchronism on the execution of dynamic flight software is discussed. It is shown that if the asynchronous microprocessors have knowledge of time, these errors can be significantly reduced through appropiate modifications of the flight software. Finally, the papear extends previous work to show that through the combined use of time referencing and stable flight algorithms, individual microprocessors can be configured to autonomously tolerate intermittent faults.

The Design of Finite State Machine for Asynchronous Replication Protocol

NASA Astrophysics Data System (ADS)

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.

Refractometric total protein concentrations in icteric serum from dogs.

PubMed

Gupta, Aradhana; Stockham, Steven L

2014-01-01

To determine whether high serum bilirubin concentrations interfere with the measurement of serum total protein concentration by refractometry and to assess potential biases among refractometer measurements. Evaluation study. Sera from 2 healthy Greyhounds. Bilirubin was dissolved in 0.1M NaOH, and the resulting solution was mixed with sera from 2 dogs from which food had been withheld to achieve various bilirubin concentrations up to 40 mg/dL. Refractometric total protein concentrations were estimated with 3 clinical refractometers. A biochemical analyzer was used to measure biuret assay-based total protein and bilirubin concentrations with spectrophotometric assays. No interference with refractometric measurement of total protein concentrations was detected with bilirubin concentrations up to 41.5 mg/dL. Biases in refractometric total protein concentrations were detected and were related to the conversion of refractive index values to total protein concentrations. Hyperbilirubinemia did not interfere with the refractometric estimation of serum total protein concentration. The agreement among total protein concentrations estimated by 3 refractometers was dependent on the method of conversion of refractive index to total protein concentration and was independent of hyperbilirubinemia.

Dynamics of in vivo power output and efficiency of Nasonia asynchronous flight muscle.

PubMed

Lehmann, Fritz-Olaf; Heymann, Nicole

2006-06-25

By simultaneously measuring aerodynamic performance, wing kinematics, and metabolic activity, we have estimated the in vivo limits of mechanical power production and efficiency of the asynchronous flight muscle (IFM) in three species of ectoparasitoid wasps genus Nasonia (N. giraulti, N. longicornis, and N. vitripennis). The 0.6 mg animals were flown under tethered flight conditions in a flight simulator that allowed modulation of power production by employing an open-loop visual stimulation technique. At maximum locomotor capacity, flight muscles of Nasonia are capable to sustain 72.2 +/- 18.3 W kg(-1) muscle mechanical power at a chemo-mechanical conversion efficiency of approximately 9.8 +/- 0.9%. Within the working range of the locomotor system, profile power requirement for flight dominates induced power requirement suggesting that the cost to overcome wing drag places the primary limit on overall flight performance. Since inertial power is only approximately 25% of the sum of induced and profile power requirements, Nasonia spp. may not benefit from elastic energy storage during wing deceleration phases. A comparison between wing size-polymorphic males revealed that wing size reduction is accompanied by a decrease in total flight muscle volume, muscle mass-specific mechanical power production, and total flight efficiency. In animals with small wings maximum total flight efficiency is below 0.5%. The aerodynamic and power estimates reported here for Nasonia are comparable to values reported previously for the fruit fly Drosophila flying under similar experimental conditions, while muscle efficiency of the tiny wasp is more at the lower end of values published for various other insects.

A massively asynchronous, parallel brain.

PubMed

Zeki, Semir

2015-05-19

Whether the visual brain uses a parallel or a serial, hierarchical, strategy to process visual signals, the end result appears to be that different attributes of the visual scene are perceived asynchronously--with colour leading form (orientation) by 40 ms and direction of motion by about 80 ms. Whatever the neural root of this asynchrony, it creates a problem that has not been properly addressed, namely how visual attributes that are perceived asynchronously over brief time windows after stimulus onset are bound together in the longer term to give us a unified experience of the visual world, in which all attributes are apparently seen in perfect registration. In this review, I suggest that there is no central neural clock in the (visual) brain that synchronizes the activity of different processing systems. More likely, activity in each of the parallel processing-perceptual systems of the visual brain is reset independently, making of the brain a massively asynchronous organ, just like the new generation of more efficient computers promise to be. Given the asynchronous operations of the brain, it is likely that the results of activities in the different processing-perceptual systems are not bound by physiological interactions between cells in the specialized visual areas, but post-perceptually, outside the visual brain.

An inter-lighting interference cancellation scheme for MISO-VLC systems

NASA Astrophysics Data System (ADS)

Kim, Kyuntak; Lee, Kyujin; Lee, Kyesan

2017-08-01

In this paper, we propose an inter-lighting interference cancellation (ILIC) scheme to reduce the interference between adjacent light-emitting diodes (LEDs) and enhance the transmission capacity of multiple-input-single-output (MISO)-visible light communication (VLC) systems. In indoor environments, multiple LEDs have normally been used as lighting sources, allowing the design of MISO-VLC systems. To enhance the transmission capacity, different data should be simultaneously transmitted from each LED; however, that can lead to interference between adjacent LEDs. In that case, relatively low-received power signals are subjected to large interference because wireless optical systems generally use intensity modulation and direct detection. Thus, only the signal with the highest received power can be detected, while the other received signals cannot be detected. To solve this problem, we propose the ILIC scheme for MISO-VLC systems. The proposed scheme preferentially detects the highest received power signal, and this signal is referred as interference signal by an interference component generator. Then, relatively low-received power signal can be detected by cancelling the interference signal from the total received signals. Therefore, the performance of the proposed scheme can improve the total average bit error rate and throughput of a MISO-VLC system.

Speech recognition by bilateral cochlear implant users in a cocktail-party setting

PubMed Central

Loizou, Philipos C.; Hu, Yi; Litovsky, Ruth; Yu, Gongqiang; Peters, Robert; Lake, Jennifer; Roland, Peter

2009-01-01

Unlike prior studies with bilateral cochlear implant users which considered only one interferer, the present study considered realistic listening situations wherein multiple interferers were present and in some cases originating from both hemifields. Speech reception thresholds were measured in bilateral users unilaterally and bilaterally in four different spatial configurations, with one and three interferers consisting of modulated noise or competing talkers. The data were analyzed in terms of binaural benefits including monaural advantage (better-ear listening) and binaural interaction. The total advantage (overall spatial release) received was 2–5 dB and was maintained with multiple interferers present. This advantage was dominated by the monaural advantage, which ranged from 1 to 6 dB and was largest when the interferers were mostly energetic. No binaural-interaction benefit was found in the present study with either type of interferer (speech or noise). While the total and monaural advantage obtained for noise interferers was comparable to that attained by normal-hearing listeners, it was considerably lower for speech interferers. This suggests that bilateral users are less capable of taking advantage of binaural cues, in particular, under conditions of informational masking. Furthermore, the use of noise interferers does not adequately reflect the difficulties experienced by bilateral users in real-life situations. PMID:19173424

Scenario Decomposition for 0-1 Stochastic Programs: Improvements and Asynchronous Implementation

DOE PAGES

Ryan, Kevin; Rajan, Deepak; Ahmed, Shabbir

2016-05-01

We recently proposed scenario decomposition algorithm for stochastic 0-1 programs finds an optimal solution by evaluating and removing individual solutions that are discovered by solving scenario subproblems. In our work, we develop an asynchronous, distributed implementation of the algorithm which has computational advantages over existing synchronous implementations of the algorithm. Improvements to both the synchronous and asynchronous algorithm are proposed. We also test the results on well known stochastic 0-1 programs from the SIPLIB test library and is able to solve one previously unsolved instance from the test set.

Finite-time synchronization of uncertain coupled switched neural networks under asynchronous switching.

PubMed

Wu, Yuanyuan; Cao, Jinde; Li, Qingbo; Alsaedi, Ahmed; Alsaadi, Fuad E

2017-01-01

This paper deals with the finite-time synchronization problem for a class of uncertain coupled switched neural networks under asynchronous switching. By constructing appropriate Lyapunov-like functionals and using the average dwell time technique, some sufficient criteria are derived to guarantee the finite-time synchronization of considered uncertain coupled switched neural networks. Meanwhile, the asynchronous switching feedback controller is designed to finite-time synchronize the concerned networks. Finally, two numerical examples are introduced to show the validity of the main results. Copyright © 2016 Elsevier Ltd. All rights reserved.

Interaction between the Stress Phase Angle (SPA) and the Oscillatory Shear Index (OSI) Affects Endothelial Cell Gene Expression.

PubMed

Amaya, Ronny; Cancel, Limary M; Tarbell, John M

2016-01-01

Hemodynamic forces play an important role in the non-uniform distribution of atherosclerotic lesions. Endothelial cells are exposed simultaneously to fluid wall shear stress (WSS) and solid circumferential stress (CS). Due to variations in impedance (global factors) and geometric complexities (local factors) in the arterial circulation a time lag arises between these two forces that can be characterized by the temporal phase angle between CS and WSS (stress phase angle-SPA). Asynchronous flows (SPA close to -180°) that are most prominent in coronary arteries have been associated with localization of atherosclerosis. Reversing oscillatory flows characterized by an oscillatory shear index (OSI) that is great than zero are also associated with atherosclerosis localization. In this study we examined the relationship between asynchronous flows and reversing flows in altering the expression of 37 genes relevant to atherosclerosis development. In the case of reversing oscillatory flow, we observed that the asynchronous condition upregulated 8 genes compared to synchronous hemodynamics, most of them proatherogenic. Upregulation of the pro-inflammatory transcription factor NFκB p65 was confirmed by western blot, and nuclear translocation of NFκB p65 was confirmed by immunofluorescence staining. A comparative study between non-reversing flow and reversing flow found that in the case of synchronous hemodynamics, reversing flow altered the expression of 11 genes, while in the case of asynchronous hemodynamics, reversing flow altered the expression of 17 genes. Reversing flow significantly upregulated protein expression of NFκB p65 for both synchronous and asynchronous conditions. Nuclear translocation of NFκB p65 was confirmed for synchronous and asynchronous conditions in the presence of flow reversal. These data suggest that asynchronous hemodynamics and reversing flow can elicit proatherogenic responses in endothelial cells compared to synchronous hemodynamics without shear stress reversal, indicating that SPA as well as reversal flow (OSI) are important parameters characterizing arterial susceptibility to disease.

Interaction between the Stress Phase Angle (SPA) and the Oscillatory Shear Index (OSI) Affects Endothelial Cell Gene Expression

PubMed Central

Amaya, Ronny; Cancel, Limary M.; Tarbell, John M.

2016-01-01

Hemodynamic forces play an important role in the non-uniform distribution of atherosclerotic lesions. Endothelial cells are exposed simultaneously to fluid wall shear stress (WSS) and solid circumferential stress (CS). Due to variations in impedance (global factors) and geometric complexities (local factors) in the arterial circulation a time lag arises between these two forces that can be characterized by the temporal phase angle between CS and WSS (stress phase angle–SPA). Asynchronous flows (SPA close to -180°) that are most prominent in coronary arteries have been associated with localization of atherosclerosis. Reversing oscillatory flows characterized by an oscillatory shear index (OSI) that is great than zero are also associated with atherosclerosis localization. In this study we examined the relationship between asynchronous flows and reversing flows in altering the expression of 37 genes relevant to atherosclerosis development. In the case of reversing oscillatory flow, we observed that the asynchronous condition upregulated 8 genes compared to synchronous hemodynamics, most of them proatherogenic. Upregulation of the pro-inflammatory transcription factor NFκB p65 was confirmed by western blot, and nuclear translocation of NFκB p65 was confirmed by immunofluorescence staining. A comparative study between non-reversing flow and reversing flow found that in the case of synchronous hemodynamics, reversing flow altered the expression of 11 genes, while in the case of asynchronous hemodynamics, reversing flow altered the expression of 17 genes. Reversing flow significantly upregulated protein expression of NFκB p65 for both synchronous and asynchronous conditions. Nuclear translocation of NFκB p65 was confirmed for synchronous and asynchronous conditions in the presence of flow reversal. These data suggest that asynchronous hemodynamics and reversing flow can elicit proatherogenic responses in endothelial cells compared to synchronous hemodynamics without shear stress reversal, indicating that SPA as well as reversal flow (OSI) are important parameters characterizing arterial susceptibility to disease. PMID:27846267

Electrical engineering unit for the reactive power control of the load bus at the voltage instability

NASA Astrophysics Data System (ADS)

Kotenev, A. V.; Kotenev, V. I.; Kochetkov, V. V.; Elkin, D. A.

2018-01-01

For the purpose of reactive power control error reduction and decrease of the voltage sags in the electric power system caused by the asynchronous motors started the mathematical model of the load bus was developed. The model was built up of the sub-models of the following elements: a transformer, a transmission line, a synchronous and an asynchronous loads and a capacitor bank load, and represents the automatic reactive power control system taking into account electromagnetic processes of the asynchronous motors started and reactive power changing of the electric power system elements caused by the voltage fluctuation. The active power/time and reactive power/time characteristics based on the recommended procedure of the equivalent electric circuit parameters calculation were obtained. The derived automatic reactive power control system was shown to eliminate the voltage sags in the electric power system caused by the asynchronous motors started.

PsychVACS: a system for asynchronous telepsychiatry.

PubMed

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.

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

NASA Astrophysics Data System (ADS)

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.

Hybrid optical CDMA-FSO communications network under spatially correlated gamma-gamma scintillation.

PubMed

Jurado-Navas, Antonio; Raddo, Thiago R; Garrido-Balsells, José María; Borges, Ben-Hur V; Olmos, Juan José Vegas; Monroy, Idelfonso Tafur

2016-07-25

In this paper, we propose a new hybrid network solution based on asynchronous optical code-division multiple-access (OCDMA) and free-space optical (FSO) technologies for last-mile access networks, where fiber deployment is impractical. The architecture of the proposed hybrid OCDMA-FSO network is thoroughly described. The users access the network in a fully asynchronous manner by means of assigned fast frequency hopping (FFH)-based codes. In the FSO receiver, an equal gain-combining technique is employed along with intensity modulation and direct detection. New analytical formalisms for evaluating the average bit error rate (ABER) performance are also proposed. These formalisms, based on the spatially correlated gamma-gamma statistical model, are derived considering three distinct scenarios, namely, uncorrelated, totally correlated, and partially correlated channels. Numerical results show that users can successfully achieve error-free ABER levels for the three scenarios considered as long as forward error correction (FEC) algorithms are employed. Therefore, OCDMA-FSO networks can be a prospective alternative to deliver high-speed communication services to access networks with deficient fiber infrastructure.

A Mathematical Tumor Model with Immune Resistance and Drug Therapy: An Optimal Control Approach

DOE PAGES

De Pillis, L. G.; Radunskaya, A.

2001-01-01

We present a competition model of cancer tumor growth that includes both the immune system response and drug therapy. This is a four-population model that includes tumor cells, host cells, immune cells, and drug interaction. We analyze the stability of the drug-free equilibria with respect to the immune response in order to look for target basins of attraction. One of our goals was to simulate qualitatively the asynchronous tumor-drug interaction known as “Jeffs phenomenon.” The model we develop is successful in generating this asynchronous response behavior. Our other goal was to identify treatment protocols that could improve standard pulsed chemotherapymore » regimens. Using optimal control theory with constraints and numerical simulations, we obtain new therapy protocols that we then compare with traditional pulsed periodic treatment. The optimal control generated therapies produce larger oscillations in the tumor population over time. However, by the end of the treatment period, total tumor size is smaller than that achieved through traditional pulsed therapy, and the normal cell population suffers nearly no oscillations.« less

A Mathematical Tumor Model with Immune Resistance and Drug Therapy: An Optimal Control Approach

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

De Pillis, L. G.; Radunskaya, A.

We present a competition model of cancer tumor growth that includes both the immune system response and drug therapy. This is a four-population model that includes tumor cells, host cells, immune cells, and drug interaction. We analyze the stability of the drug-free equilibria with respect to the immune response in order to look for target basins of attraction. One of our goals was to simulate qualitatively the asynchronous tumor-drug interaction known as “Jeffs phenomenon.” The model we develop is successful in generating this asynchronous response behavior. Our other goal was to identify treatment protocols that could improve standard pulsed chemotherapymore » regimens. Using optimal control theory with constraints and numerical simulations, we obtain new therapy protocols that we then compare with traditional pulsed periodic treatment. The optimal control generated therapies produce larger oscillations in the tumor population over time. However, by the end of the treatment period, total tumor size is smaller than that achieved through traditional pulsed therapy, and the normal cell population suffers nearly no oscillations.« less

Proactive Semantic Interference is Associated with Total and Regional Abnormal Amyloid Load in Non-Demented Community-Dwelling Elders: A Preliminary Study.

PubMed

Loewenstein, David A; Greig, Maria T; Curiel, Rosie; Rodriguez, Rosemarie; Wicklund, Meredith; Barker, Warren W; Hidalgo, Jacqueline; Rosado, Marian; Duara, Ranjan

2015-12-01

To evaluate the relationship between susceptibility to proactive semantic interference (PSI) and retroactive semantic interference (RSI) and brain amyloid load in non-demented elders. 27 participants (11 cognitively normal [CN] with subjective memory complaints, 8 CN without memory complaints, and 8 with mild cognitive impairment [MCI]) underwent complete neurological and neuropsychological evaluations. Participants also received the Semantic Interference Test (SIT) and AV-45 amyloid PET imaging. High levels of association were present between total amyloid load, regional amyloid levels, and the PSI measure (in the entire sample and a subsample excluding MCI subjects). RSI and other memory measures showed much weaker associations or no associations with total and regional amyloid load. No associations between amyloid levels and non-memory performance were observed. In non-demented individuals, vulnerability to PSI was highly associated with total and regional beta-amyloid load and may be an early cognitive marker of brain pathology. Copyright © 2015 American Association for Geriatric Psychiatry. Published by Elsevier Inc. All rights reserved.

A Communication Perspective on Sexual Harassment: Affiliative Nonverbal Behaviors in Asynchronous Relationships.

ERIC Educational Resources Information Center

Hickson, Mark, III; And Others

1991-01-01

Develops a communication perspective on sexual harassment in asynchronous relationships. Presents a six-step process model to predict private harassing behavior among faculty members in higher education. Makes suggestions for prevention of sexual harassment. (SR)

Potential for chlorate interference in ion chromatographic determination of total nitrogen in natural waters following alkaline persulfate digestion.

PubMed

Halstead, J A; Edwards, J; Soracco, R J; Armstrong, R W

1999-10-01

Determination of total nitrogen in aqueous samples after thermal potassium peroxydisulfate (persulfate) digestion is a commonly used alternative to the tedious Kjeldahl procedure. When ion chromatography is used to quantify the nitrate formed during digestion, there is a potential for interference from a chlorate peak if the digested sample initially contained chloride in concentrations close to or greater than the concentration of nitrogen. It was determined that this interference can be avoided either by using chromatographic conditions which cleanly resolve the nitrate and chlorate peaks (e.g., the Dionex AG9-HG column) or by using digestion reagent concentrations chosen to maintain a high pH throughout the digestion. The second alternative is not a viable option for investigators using a single digestion for both total nitrogen (TN) and total phosphorus (TP) analysis.

Interference and the Law of Energy Conservation

ERIC Educational Resources Information Center

Drosd, Robert; Minkin, Leonid; Shapovalov, Alexander S.

2014-01-01

Introductory physics textbooks consider interference to be a process of redistribution of energy from the wave sources in the surrounding space resulting in constructive and destructive interferences. As one can expect, the total energy flux is conserved. However, one case of apparent non-conservation energy attracts great attention. Imagine that…

Student Satisfaction with Asynchronous Learning

ERIC Educational Resources Information Center

Dziuban, Charles; Moskal, Patsy; Brophy, Jay; Shea, Peter

2007-01-01

The authors discuss elements that potentially impact student satisfaction with asynchronous learning: the media culture, digital, personal and mobile technologies, student learning preferences, pedagogy, complexities of measurement, and the digital generation. They describe a pilot study to identify the underlying dimensions of student…

Software and hardware complex for research and management of the separation process

NASA Astrophysics Data System (ADS)

Borisov, A. P.

2018-01-01

The article is devoted to the development of a program for studying the operation of an asynchronous electric drive using vector-algorithmic switching of windings, as well as the development of a hardware-software complex for controlling parameters and controlling the speed of rotation of an asynchronous electric drive for investigating the operation of a cyclone. To study the operation of an asynchronous electric drive, a method was used in which the average value of flux linkage is found and a method for vector-algorithmic calculation of the power and electromagnetic moment of an asynchronous electric drive feeding from a single-phase network is developed, with vector-algorithmic commutation, and software for calculating parameters. The software part of the complex allows to regulate the speed of rotation of the motor by vector-algorithmic switching of transistors or, using pulse-width modulation (PWM), set any engine speed. Also sensors are connected to the hardware-software complex at the inlet and outlet of the cyclone. The developed cyclone with an inserted complex allows to receive high efficiency of product separation at various entrance speeds. At an inlet air speed of 18 m / s, the cyclone’s maximum efficiency is achieved. For this, it is necessary to provide the rotational speed of an asynchronous electric drive with a frequency of 45 Hz.

An exploration of teaching presence in online interprofessional education facilitation.

PubMed

Evans, Sherryn Maree; Ward, Catherine; Reeves, Scott

2017-07-01

Although the prevalence of online asynchronous interprofessional education (IPE) has increased in the last decade, little is known about the processes of facilitation in this environment. The teaching presence element of the Community of Inquiry Framework offers an approach to analyze the contributions of online facilitators, however, to date it has only been used on a limited basis in health professions education literature. Using an exploratory case study design, we explored the types of contributions made by IPE facilitators to asynchronous interprofessional team discussions by applying the notion of teaching presence. Using a purposeful sampling approach, we analyzed 14 facilitators' contributions to asynchronous team discussion boards in an online IPE course. We analyzed data using directed content analysis based on the key indicators of teaching presence. The online IPE facilitators undertook the three critical pedagogical functions identified in teaching presence: facilitating discourse, direct instruction, and instructional design and organization. While our data fitted well with a number of key activities embedded in these three functions, further modification of the teaching presence concept was needed to describe our facilitators' teaching presence. This study provides an initial insight into the key elements of online asynchronous IPE facilitation. Further research is required to continue to illuminate the complexity of online asynchronous IPE facilitation.

Asynchronous P300 classification in a reactive brain-computer interface during an outlier detection task

NASA Astrophysics Data System (ADS)

Krumpe, Tanja; Walter, Carina; Rosenstiel, Wolfgang; Spüler, Martin

2016-08-01

Objective. In this study, the feasibility of detecting a P300 via an asynchronous classification mode in a reactive EEG-based brain-computer interface (BCI) was evaluated. The P300 is one of the most popular BCI control signals and therefore used in many applications, mostly for active communication purposes (e.g. P300 speller). As the majority of all systems work with a stimulus-locked mode of classification (synchronous), the field of applications is limited. A new approach needs to be applied in a setting in which a stimulus-locked classification cannot be used due to the fact that the presented stimuli cannot be controlled or predicted by the system. Approach. A continuous observation task requiring the detection of outliers was implemented to test such an approach. The study was divided into an offline and an online part. Main results. Both parts of the study revealed that an asynchronous detection of the P300 can successfully be used to detect single events with high specificity. It also revealed that no significant difference in performance was found between the synchronous and the asynchronous approach. Significance. The results encourage the use of an asynchronous classification approach in suitable applications without a potential loss in performance.

First case report of testosterone assay-interference in a female taking maca (Lepidium meyenii).

PubMed

Srikugan, L; Sankaralingam, A; McGowan, B

2011-03-25

A young female with prolonged intermenstrual bleeding was found to have raised total plasma testosterone of 25.8 nmol/l (NR<2.9 nmol/l) using the Roche Elecsys Testosterone I immunoassay without clinical features of virulisation. Few months ago investigations for lethargy and low libido had shown normal total testosterone of 0.8 nmol/l. Further history revealed that she was using maca extract to improve her lethargy and low libido. Maca is traditionally used for its aphrodisiac and fertility-enhancing properties. Maca use has not been shown to affect serum testosterone in mice and human studies. Immunoassay interference with maca was suspected. Testosterone immunoassays use monoclonal antibodies specifically directed against testosterone. They are prone to interference from androgenic compounds. Reanalysis of the original serum sample using Elecsys Testosterone II assay, a higher affinity assay, revealed a total testosterone level of 2.9 nmol/l. It is important to exclude assay interference when testosterone level is greater than 5 nmol/l without supportive clinical signs.

First case report of testosterone assay-interference in a female taking maca (Lepidium meyenii)

PubMed Central

Srikugan, L; Sankaralingam, A; McGowan, B

2011-01-01

A young female with prolonged intermenstrual bleeding was found to have raised total plasma testosterone of 25.8 nmol/l (NR<2.9 nmol/l) using the Roche Elecsys Testosterone I immunoassay without clinical features of virulisation. Few months ago investigations for lethargy and low libido had shown normal total testosterone of 0.8 nmol/l. Further history revealed that she was using maca extract to improve her lethargy and low libido. Maca is traditionally used for its aphrodisiac and fertility-enhancing properties. Maca use has not been shown to affect serum testosterone in mice and human studies. Immunoassay interference with maca was suspected. Testosterone immunoassays use monoclonal antibodies specifically directed against testosterone. They are prone to interference from androgenic compounds. Reanalysis of the original serum sample using Elecsys Testosterone II assay, a higher affinity assay, revealed a total testosterone level of 2.9 nmol/l. It is important to exclude assay interference when testosterone level is greater than 5 nmol/l without supportive clinical signs. PMID:22700073

Learning Objects and Gerontology

ERIC Educational Resources Information Center

Weinreich, Donna M.; Tompkins, Catherine J.

2006-01-01

Virtual AGE (vAGE) is an asynchronous educational environment that utilizes learning objects focused on gerontology and a learning anytime/anywhere philosophy. This paper discusses the benefits of asynchronous instruction and the process of creating learning objects. Learning objects are "small, reusable chunks of instructional media" Wiley…

Redundant Asynchronous Microprocessor System

NASA Technical Reports Server (NTRS)

Meyer, G.; Johnston, J. O.; Dunn, W. R.

1985-01-01

Fault-tolerant computer structure called RAMPS (for redundant asynchronous microprocessor system) has simplicity of static redundancy but offers intermittent-fault handling ability of complex, dynamically redundant systems. New structure useful wherever several microprocessors are employed for control - in aircraft, industrial processes, robotics, and automatic machining, for example.

A Rasch analysis of the Brief Pain Inventory Interference subscale reveals three dimensions and an age bias.

PubMed

Walton, David M; Beattie, Tyler; Putos, Joseph; MacDermid, Joy C

2016-06-01

The Brief Pain Inventory is composed of two quantifiable scales: pain severity and pain interference. The reported factor structure of the interference subscale is not consistent in the extant literature, with no clear choice between a single- or two-factor structure. Here, we report on the results of Rasch-based analysis of the interference subscale using a large population-based ambulatory patient database (the Quebec Pain Registry). Observational cohort. A total of 1,000 responses were randomly drawn from a total database of 5,654 for this analysis. Both the original 7-item and an expanded 10-item version (Tyler 2002) of the interference subscale were evaluated. Rasch analysis revealed significant misfit of both versions of the scale, with the original 7-item version outperforming the expanded 10-item version. Analysis of dimensionality revealed that both versions showed improved model fit when considered two subscales (affective and physical interference) with the item on sleep interference removed or considered separately. Additionally, significant uniform differential item functioning was identified for 6 of the 7 original items when the sample was stratified by age above or below 55 years. The interference subscale achieved adequate model fit when considered as two separate subscales with age as a mediator of response, while interpreting the sleep interference item separately. A transformation matrix revealed that in all cases, ordinal-level change at the extreme ends of the scale appears to be more meaningful than does a similar change at the midpoints. The Interference subscale of the BPI should be interpreted as two separate subscales (Affective Interference, Physical Interference) with the sleep item removed or interpreted separately for optimal fit to the Rasch model. Implications for research and clinical use are discussed. Copyright © 2016 Elsevier Inc. All rights reserved.

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

PubMed

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.

Highly Scalable Asynchronous Computing Method for Partial Differential Equations: A Path Towards Exascale

NASA Astrophysics Data System (ADS)

Konduri, Aditya

Many natural and engineering systems are governed by nonlinear partial differential equations (PDEs) which result in a multiscale phenomena, e.g. turbulent flows. Numerical simulations of these problems are computationally very expensive and demand for extreme levels of parallelism. At realistic conditions, simulations are being carried out on massively parallel computers with hundreds of thousands of processing elements (PEs). It has been observed that communication between PEs as well as their synchronization at these extreme scales take up a significant portion of the total simulation time and result in poor scalability of codes. This issue is likely to pose a bottleneck in scalability of codes on future Exascale systems. In this work, we propose an asynchronous computing algorithm based on widely used finite difference methods to solve PDEs in which synchronization between PEs due to communication is relaxed at a mathematical level. We show that while stability is conserved when schemes are used asynchronously, accuracy is greatly degraded. Since message arrivals at PEs are random processes, so is the behavior of the error. We propose a new statistical framework in which we show that average errors drop always to first-order regardless of the original scheme. We propose new asynchrony-tolerant schemes that maintain accuracy when synchronization is relaxed. The quality of the solution is shown to depend, not only on the physical phenomena and numerical schemes, but also on the characteristics of the computing machine. A novel algorithm using remote memory access communications has been developed to demonstrate excellent scalability of the method for large-scale computing. Finally, we present a path to extend this method in solving complex multi-scale problems on Exascale machines.

Pronuclear synchronization and nuclear morphology of mature and in vitro matured oocytes in the rat: an ultrastructural study.

PubMed

Cincik, M; Baykal, B; Zeteroglu, S; Onalan, G; Ceyhan, S T; Ergur, R

2005-01-01

The objective of this study was to evaluate synchronous and asynchronous pronucleus (PN) formation and the related patterns of juxtapositional nucleolus (n) formation in immature (prophase I [PI] and metaphase I [MI]) and mature (metaphase II [MII]) oocytes after fertilization, both ultrastructurally and at the level of light microscope. A single dose of 15 IU gonadotrophin was injected subcutaneously to twenty four 26-wk-old, female Wistar rats to induce ovulation. Human chorionic gonadotrophin (4 IU) was administered 40 h later, and after 4-6 h the ovaries were dissected, and the oocytes were aspirated. A total of 214 rat oocytes were classified according to a maturation index as follows: group I, 80 PI oocytes; group II, 50 MI oocytes; and group III, 84 MII oocytes. Immature oocytes were in vitro matured for 18-36 h. Spermatozoa were acquired by microepididymal sperm aspiration and processed using swim-up technique. Intracytoplasmic sperm injection was performed on mature oocytes after 2 h of incubation and on in vitro matured (IVM) oocytes 4 h after maturation. Pronuclear synchronization [both pronucleases (PNs) centrally located, equal sized, with equal numbers and sizes of juxtapositional nucleoli (Nn)] was observed in fertilized oocytes. Asynchronous PN formation (diversity between male and female PNs, related to dimensions, localization, and the number of Nn) in groups I, II, and III was found in 75, 86, and 47% of preembryos, respectively. There was a significant difference of synchronous pronuclear formation between mature and IVM oocytes (P < 0.05). In IVM oocytes, asynchronous PN formation is high, and juxtapositional pronucleolar patterns are observed to be low by transmission electron microscope (TEM).

Innovative Methods for Providing Instruction to Distance Students Using Technology.

ERIC Educational Resources Information Center

Pival, Paul R.; Tunon, Johanna

2001-01-01

Examines three innovative methods tried at Nova Southeastern University for providing quality bibliographic instruction to distance students: one synchronous, one asynchronous, and one that combined features from both synchronous and asynchronous methods of delivering instruction. Topics include compressed video, collaborative groupware, streaming…

Miscellany of Students' Satisfaction in an Asynchronous Learning Environment

ERIC Educational Resources Information Center

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…

Developing asynchronous online interprofessional education.

PubMed

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

PubMed

Zhou, Keming; Cherra, Salvatore J; Goncharov, Alexandr; Jin, Yishi

2017-05-09

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 Ca 2+ binding and membrane association domains. These results reveal a synaptic mechanism implicating asynchronous release in regulation of excitation-inhibition balance. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

High-Throughput Bit-Serial LDPC Decoder LSI Based on Multiple-Valued Asynchronous Interleaving

NASA Astrophysics Data System (ADS)

Onizawa, Naoya; Hanyu, Takahiro; Gaudet, Vincent C.

This paper presents a high-throughput bit-serial low-density parity-check (LDPC) decoder that uses an asynchronous interleaver. Since consecutive log-likelihood message values on the interleaver are similar, node computations are continuously performed by using the most recently arrived messages without significantly affecting bit-error rate (BER) performance. In the asynchronous interleaver, each message's arrival rate is based on the delay due to the wire length, so that the decoding throughput is not restricted by the worst-case latency, which results in a higher average rate of computation. Moreover, the use of a multiple-valued data representation makes it possible to multiplex control signals and data from mutual nodes, thus minimizing the number of handshaking steps in the asynchronous interleaver and eliminating the clock signal entirely. As a result, the decoding throughput becomes 1.3 times faster than that of a bit-serial synchronous decoder under a 90nm CMOS technology, at a comparable BER.

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

PubMed

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.

Asynchronous updates can promote the evolution of cooperation on multiplex networks

NASA Astrophysics Data System (ADS)

Allen, James M.; Hoyle, Rebecca B.

2017-04-01

We study the importance to the frequency of cooperation of the choice of updating strategies in a game played asynchronously or synchronously across layers in a multiplex network. Updating asynchronously in the public goods game leads to higher frequencies of cooperation compared to synchronous updates. How large this effect is depends on the sensitivity of the game dynamics to changes in the number of cooperators surrounding a player, with the largest effect observed when players payoffs are small. The discovery of this effect enhances understanding of cooperation on multiplex networks, and demonstrates a new way to maintain cooperation in these systems.

Control strategy for a variable-speed wind energy conversion system

NASA Technical Reports Server (NTRS)

Jacob, A.; Veillette, D.; Rajagopalan, V.

1979-01-01

A control concept for a variable-speed wind energy conversion system is proposed, for which a self-exited asynchronous cage generator is used along with a system of thyristor converters. The control loops are the following: (1) regulation of the entrainment speed as function of available mechanical energy by acting on the resistance couple of the asynchronous generator; (2) control of electric power delivered to the asynchronous machine, functioning as a motor, for start-up of the vertical axis wind converter; and (3) limitation of the slip value, and by consequence, of the induction currents in the presence of sudden variations of input parameters.

Asynchronous versus Synchronous Learning in Pharmacy Education

ERIC Educational Resources Information Center

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.…

Knowledge Building in Asynchronous Discussion Groups: Going Beyond Quantitative Analysis

ERIC Educational Resources Information Center

Schrire, Sarah

2006-01-01

This contribution examines the methodological challenges involved in defining the collaborative knowledge-building processes occurring in asynchronous discussion and proposes an approach that could advance understanding of these processes. The written protocols that are available to the analyst provide an exact record of the instructional…

Creating and Nurturing Distributed Asynchronous Learning Environments.

ERIC Educational Resources Information Center

Kochtanek, Thomas R.; Hein, Karen K.

2000-01-01

Describes the evolution of a university course from a face-to-face experience to a Web-based asynchronous learning environment. Topics include cognition and learning; distance learning and distributed learning; student learning communities and the traditional classroom; the future as it relates to education and technology; collaborative student…

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

ERIC Educational Resources Information Center

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…

Creating Asynchronous Online Learning Communities

ERIC Educational Resources Information Center

Kerr, Crystal

2009-01-01

This research project examined how to develop and sustain online, asynchronous learning communities in continuous intake, distance education environments for learners in grades 7 through 10. The study is an action research project that is based upon in-depth, qualitative data. Interviews were conducted with distance education teachers,…

Mathematical Modelling of Allelopathy: IV. Assessment of Contributions of Competition and Allelopathy to Interference by Barley

PubMed Central

Liu, De Li; An, Min; Johnson, I.R.; Lovett, J.V.

2005-01-01

One of the main challenges to the research on allelopathy is technically the separation of allelopathic effect from competition, and quantitatively, the assessment of the contribution of each component to overall interference. A simple mathematical model is proposed to calculate the contribution of allelopathy and competition to interference. As an example of applying the quantitative model to interference by barley (Hordeum vulgare cv. Triumph), the approach used was an addition of allelopathic effect, by an equivalent amount, to the environment of the test plant (white mustard, Sinapis alba), rather than elimination of competition. Experiments were conducted in glasshouse to determine the magnitude of the contributions of allelopathy and competition to interference by barley. The leachates of living barley roots significantly reduced the total dry weight of white mustard. The model involved the calculation of adjusted densities to an equivalent basis for modelling the contribution of allelopathy and competition to total interference. The results showed that allelopathy contributed 40%, 37% and 43% to interference by barley at 6, 12 and 18 white mustard pot−1. The consistency in magnitude of the calculated contribution of allelopathic effect by barley across various densities of receiver plant suggested that the adjusted equivalent density is effective and that the model is able to assess the contribution of each component of interference regardless of the density of receiver plant. PMID:19330162

Efficient algorithms for solution of interference cancellation and channel estimation for mobile OFDM system

NASA Astrophysics Data System (ADS)

Fan, Tong-liang; Wen, Yu-cang; Kadri, Chaibou

Orthogonal frequency-division multiplexing (OFDM) is robust against frequency selective fading because of the increase of the symbol duration. However, the time-varying nature of the channel causes inter-carrier interference (ICI) which destroys the orthogonal of sub-carriers and degrades the system performance severely. To alleviate the detrimental effect of ICI, there is a need for ICI mitigation within one OFDM symbol. We propose an iterative Inter-Carrier Interference (ICI) estimation and cancellation technique for OFDM systems based on regularized constrained total least squares. In the proposed scheme, ICI aren't treated as additional additive white Gaussian noise (AWGN). The effect of Inter-Carrier Interference (ICI) and inter-symbol interference (ISI) on channel estimation is regarded as perturbation of channel. We propose a novel algorithm for channel estimation o based on regularized constrained total least squares. Computer simulations show that significant improvement can be obtained by the proposed scheme in fast fading channels.

Interference drag in a simulated wing-fuselage juncture

NASA Technical Reports Server (NTRS)

Kubendran, L. R.; Mcmahon, H.; Hubbartt, J. E.

1984-01-01

The interference drag in a wing fuselage juncture as simulated by a flat plate and a body of constant thickness having a 1.5:1 elliptical leading edge is evaluated experimentally. The experimental measurements consist of mean velocity data taken with a hot wire at a streamwise location corresponding to 16 body widths downstream of the body leading edge. From these data, the interference drag is determined by calculating the total momentum deficit (momentum area) in the juncture and also in the two dimensional turbulent boundary layers on the flat plate and body at locations sufficiently far from the juncture flow effect. The interference drag caused by the juncture drag as measured at this particular streamwise station is -3% of the total drag due to the flat plate and body boundary layers in isolation. If the body is considered to be a wing having a chord and span equal to 16 body widths, the interference drag due to the juncture is only -1% of the frictional drag of one surface of such a wing.

The Necessity of Real-Time: Fact and Fiction in Digital Reference Systems.

ERIC Educational Resources Information Center

Lankes, R. David; Shostack, Pauline

2002-01-01

Discussion of digital reference services and the use of real-time versus asynchronous services such as email focuses on data from the AskERIC digital reference service to demonstrate that asynchronous services are not only useful but may have greater utility than real-time systems. (Author/LRW)

Positioning (Mis)Aligned: The (Un)Making of Intercultural Asynchronous Computer-Mediated Communication

ERIC Educational Resources Information Center

Wu, Zhiwei

2018-01-01

Framed from positioning theory and dynamic systems theory, the paper reports on a naturalistic study involving four Chinese participants and their American peers in an intercultural asynchronous computer-mediated communication (ACMC) activity. Based on the moment-by-moment analysis and triangulation of forum posts, reflective essays, and…

Automated Feedback as a Convergence Tool

ERIC Educational Resources Information Center

Chenoweth, Tim; Corral, Karen; Scott, Kit

2016-01-01

This study evaluates two content delivery options for teaching a programming language to determine whether an asynchronous format can achieve the same learning efficacy as a traditional lecture (face-to-face) format. We use media synchronicity theory as a guide to choose media capabilities to incorporate into an asynchronous tutorial used…

Designing a Web-Based Asynchronous Innovation/Entrepreneurism Course

ERIC Educational Resources Information Center

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 Assessment in a Large Lecture Marketing Course

ERIC Educational Resources Information Center

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…

Principles for Effective Asynchronous Online Instruction in Religious Studies

ERIC Educational Resources Information Center

McGuire, Beverley

2017-01-01

Asynchronous online instruction has become increasingly popular in the field of religious studies. However, despite voluminous research on online learning in general and numerous articles on online theological instruction, there has been little discussion of how to effectively design and deliver online undergraduate courses in religious studies.…

Investigating Asynchronous Online Communication: A Connected Stance Revealed

ERIC Educational Resources Information Center

Wegmann, Susan J.; McCauley, Joyce K.

2014-01-01

This research project explores the effects of altering the structure of discussion board formats to increase students' engagement and participation. This paper will present the findings of a two-university, two-class research project in which asynchronous discussion board entries were analyzed for substance. By using oral discourse analysis…

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

ERIC Educational Resources Information Center

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…

Developing a Successful Asynchronous Online Extension Program for Forest Landowners

ERIC Educational Resources Information Center

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…

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

ERIC Educational Resources Information Center

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…

Language Use in Asynchronous Computer-Mediated Communication in Taiwan

ERIC Educational Resources Information Center

Huang, Daphne Li-jung

2009-01-01

This paper describes how Chinese-English bilinguals in Taiwan use their languages in asynchronous computer-mediated communication, specifically, via Bulletin Board System (BBS) and email. The main data includes two types: emails collected from a social network and postings collected from two BBS websites. By examining patterns of language choice…

Students' Use of Asynchronous Discussions for Academic Discourse Socialization

ERIC Educational Resources Information Center

Beckett, Gulbahar H.; Amaro-Jimenez, Carla; Beckett, Kelvin S.

2010-01-01

Our universities are becoming increasingly diverse at the same time as online asynchronous discussions (OADs) are emerging as the most important forum for computer mediated communication (CMC) in distance education. But there is shortage of studies that explore how graduate students from different ethnic, linguistic and cultural backgrounds use…

Effects of Belongingness and Synchronicity on Face-to-Face and Computer-Mediated Online Cooperative Pedagogy

ERIC Educational Resources Information Center

Saltarelli, Andrew John

2012-01-01

Previous research suggests asynchronous online computer-mediated communication (CMC) has deleterious effects on certain cooperative learning pedagogies (e.g., constructive controversy), but the processes underlying this effect and how it may be ameliorated remain unclear. This study tests whether asynchronous CMC thwarts belongingness needs…

Synchronous versus Asynchronous CMC and Transfer to Japanese Oral Performance

ERIC Educational Resources Information Center

Hirotani, Maki

2009-01-01

This study investigated the effects of synchronous and asynchronous CMC (computer-mediated communication)on the development of linguistic features of learners' speech in Japanese. Using learners from fourth-semester Japanese classes, the following research questions were examined: (a) Does CMC have positive effects on the development of oral…

A Group Intelligence-Based Asynchronous Argumentation Learning-Assistance Platform

ERIC Educational Resources Information Center

Huang, Chenn-Jung; Chang, Shun-Chih; Chen, Heng-Ming; Tseng, Jhe-Hao; Chien, Sheng-Yuan

2016-01-01

Structured argumentation support environments have been built and used in scientific discourse in the literature. However, to the best our knowledge, there is no research work in the literature examining whether student's knowledge has grown during learning activities with asynchronous argumentation. In this work, an intelligent computer-supported…

Participation, Interaction and Social Presence: An Exploratory Study of Collaboration in Online Peer Review Groups

ERIC Educational Resources Information Center

Zhao, Huahui; Sullivan, Kirk P. H.; Mellenius, Ingmarie

2014-01-01

A key reason for using asynchronous computer conferencing in instruction is its potential for supporting collaborative learning. However, few studies have examined collaboration in computer conferencing. This study examined collaboration in six peer review groups within an asynchronous computer conferencing. Eighteen tertiary students participated…

Asynchronous Group Review of EFL Writing: Interactions and Text Revisions

ERIC Educational Resources Information Center

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…

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

ERIC Educational Resources Information Center

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

ERIC Educational Resources Information Center

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…

Relationship of Metacognitive Monitoring with Interaction in an Asynchronous Online Discussion Forum

ERIC Educational Resources Information Center

Topcu, Abdullah

2010-01-01

Monitoring one's own performance accurately is essential for information-processing and self-regulation, which are indispensable in an online learning environment. In this article, the effect of metacognitive monitoring (MM) on interaction in an asynchronous online discussion forum was investigated. Transcripts of this forum, which was integrated…

Using Computer-Mediated Communication to Establish Social and Supportive Environments in Teacher Education

ERIC Educational Resources Information Center

Arnold, Nike; Ducate, Lara; Lomicka, Lara; Lord, Gillian

2005-01-01

This article examines social presence in virtual asynchronous learning communities among foreign language teachers. We present the findings of two studies investigating cross-institutional asynchronous forums created to engage participants in online dialogues regarding their foreign language teacher preparation experiences in and out of the…

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

ERIC Educational Resources Information Center

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…

Adding the Human Touch to Asynchronous Online Learning

ERIC Educational Resources Information Center

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…

Increasing Student Engagement Using Asynchronous Learning

ERIC Educational Resources Information Center

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…

F-16 Instructional Sequencing Plan Report.

DTIC Science & Technology

1981-03-01

information). 2. Interference (learning of some tasks interferes with the learning of other tasks when they possess similar but confusing differences ...profound effect on the total training expense. This increases the desirability of systematic, precise methods of syllabus generation. Inherent in a given...the expensive to acquire. resource. Least cost The syllabus must Select sequences which provide a least total make maximum use of cost method of

Interference in the gg→h→γγ On-Shell Rate and the Higgs Boson Total Width.

PubMed

Campbell, John; Carena, Marcela; Harnik, Roni; Liu, Zhen

2017-11-03

We consider interference between the Higgs signal and QCD background in gg→h→γγ and its effect on the on-shell Higgs rate. The existence of sizable strong phases leads to destructive interference of about 2% of the on-shell cross section in the standard model. This effect can be enhanced by beyond the standard model physics. In particular, since it scales differently from the usual rates, the presence of interference allows indirect limits to be placed on the Higgs width in a novel way, using on-shell rate measurements. Our study motivates further QCD calculations to reduce uncertainties. We discuss possible width-sensitive observables, both using total and differential rates and find that the HL-LHC can potentially indirectly constrain widths of order tens of MeV.

An experimental and analytical study of the aerodynamic interference effects between two Sears-Haack bodies at Mach 2.7. M.S. Thesis - George Washington Univ.

NASA Technical Reports Server (NTRS)

Bantle, J. W.

1985-01-01

Aerodynamic interference effects were studied for two slender, streamlined bodies of revolution at Mach 2.7. A wind tunnel investigation produced force and moment data and measurements of pressure distributions on the bodies. As these bodies remained parallel with each other and with the freestream flow, their relative lateral and longitudinal spacing were varied. Results of theoretical methods were used in the analysis of results. The interference effects between the two bodies yielded less total drag than a single body of equal total volume and the same length.

Interference of ascorbic acid with chemical analytes.

PubMed

Meng, Qing H; Irwin, William C; Fesser, Jennifer; Massey, K Lorne

2005-11-01

Ascorbic acid can interfere with methodologies involving redox reactions, while comprehensive studies on main chemistry analysers have not been reported. We therefore attempted to determine the interference of ascorbic acid with analytes on the Beckman Synchron LX20. Various concentrations of ascorbic acid were added to serum, and the serum analytes were measured on the LX20. With a serum ascorbic acid concentration of 12.0 mmol/L, the values for sodium, potassium, calcium and creatinine increased by 43%, 58%, 103% and 26%, respectively (P<0.01). With a serum ascorbic acid concentration of 12.0 mmol/L, the values for chloride, total bilirubin and uric acid decreased by 33%, 62% and 83%, respectively (P<0.01), and were undetectable for total cholesterol, triglyceride, ammonia and lactate. There was no definite influence of ascorbic acid on analytical values for total CO(2), urea, glucose, phosphate, total protein, albumin, amylase, creatine kinase, creatine kinase-MB, aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, total iron, unbound iron-binding capacity or magnesium. Ascorbic acid causes a false increase in sodium, potassium, calcium and creatinine results and a false decrease in chloride, total bilirubin, uric acid, total cholesterol, triglyceride, ammonia and lactate results.

On the design of high-speed energy-efficient successive-approximation logic for asynchronous SAR ADCs

NASA Astrophysics Data System (ADS)

Yang, Jiaqi; Li, Ting; Yu, Mingyuan; Zhang, Shuangshuang; Lin, Fujiang; He, Lin

2017-08-01

This paper analyzes the power consumption and delay mechanisms of the successive-approximation (SA) logic of a typical asynchronous SAR ADC, and provides strategies to reduce both of them. Following these strategies, a unique direct-pass SA logic is proposed based on a full-swing once-triggered DFF and a self-locking tri-state gate. The unnecessary internal switching power of a typical TSPC DFF, which is commonly used in the SA logic, is avoided. The delay of the ready detector as well as the sequencer is removed from the critical path. A prototype SAR ADC based on the proposed SA logic is fabricated in 130 nm CMOS. It achieves a peak SNDR of 56.3 dB at 1.2 V supply and 65 MS/s sampling rate, and has a total power consumption of 555 μW, while the digital part consumes only 203 μW. Project supported by the National Natural Science Foundation of China (Nos. 61204033, 61331015), the Fundamental Research Funds for the Central Universities (No. WK2100230015), and the Funds of Science and Technology on Analog Integrated Circuit Laboratory (No. 9140C090111150C09041).

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

NASA Astrophysics Data System (ADS)

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

2007-12-01

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 107 are achieved. We present examples of the high-sensitivity detection of coherent phonons in superlattices and of the coherent acoustic vibration of metallic nanoparticles.

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

NASA Astrophysics Data System (ADS)

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

2015-06-01

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].

Emotional first aid for a suicide crisis: comparison between Telephonic hotline and internet.

PubMed

Gilat, Itzhak; Shahar, Golan

2007-01-01

The telephone and the internet have become popular sources of psychological help in various types of distress, including a suicide crisis. To gain more insight into the unique features of these media, we compared characteristics of calls to three technologically mediated sources of help that are part of the volunteer-based Israeli Association for Emotional First Aid (ERAN): Telephonic hotline (n = 4426), personal chat (n = 373) and an asynchronous online support group (n = 954). Threats of suicide were much more frequent among participants in the asynchronous support group than the telephone and personal chat. These findings encourage further research into suicide-related interpersonal exchanges in asynchronous online support groups.

Asynchronous emergence by loggerhead turtle (Caretta caretta) hatchlings

NASA Astrophysics Data System (ADS)

Houghton, J. D. R.; 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.

Asynchronous, macrotasked relaxation strategies for the solution of viscous, hypersonic flows

NASA Technical Reports Server (NTRS)

Gnoffo, Peter A.

1991-01-01

A point-implicit, asynchronous macrotasked relaxation of the steady, thin-layer, Navier-Stokes equations is presented. The method employs multidirectional, single-level storage Gauss-Seidel relaxation sweeps, which effectively communicate perturbations across the entire domain in 2n sweeps, where n is the dimension of the domain. In order to enhance convergence the application of relaxation factors to specific components of the Jacobian is examined using a stability analysis of the advection and diffusion equations. Attention is also given to the complications associated with asynchronous multitasking. Solutions are generated for hypersonic flows over blunt bodies in two and three dimensions with chemical reactions, utilizing single-tasked and multitasked relaxation strategies.

Interference Fringes of Solar Acoustic Waves around Sunspots

NASA Astrophysics Data System (ADS)

Chou, Dean-Yi; Zhao, Hui; Yang, Ming-Hsu; Liang, Zhi-Chao

2012-10-01

Solar acoustic waves are scattered by a sunspot due to the interaction between the acoustic waves and the sunspot. The sunspot, excited by the incident wave, generates the scattered wave. The scattered wave is added to the incident wave to form the total wave around the sunspot. The interference fringes between the scattered wave and the incident wave are visible in the intensity of the total wave because the coherent time of the incident wave is of the order of a wave period. The strength of the interference fringes anti-correlates with the width of temporal spectra of the incident wave. The separation between neighboring fringes increases with the incident wavelength and the sunspot size. The strength of the fringes increases with the radial order n of the incident wave from n = 0 to n = 2, and then decreases from n = 2 to n = 5. The interference fringes play a role analogous to holograms in optics. This study suggests the feasibility of using the interference fringes to reconstruct the scattered wavefields of the sunspot, although the quality of the reconstructed wavefields is sensitive to the noise and errors in the interference fringes.

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

ERIC Educational Resources Information Center

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…

At a Distance: A Comparative Study of Distance Delivery Modalities for PhD Nursing Students

ERIC Educational Resources Information Center

Black, Andrew G.

2010-01-01

This study sought to ascertain and compare the attitudes and perceptions of PhD nursing students attending their coursework through synchronous and asynchronous means at two different universities. Many studies have been performed comparing both synchronous videoconferencing and asynchronous online education with the traditional classroom, but no…

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

ERIC Educational Resources Information Center

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…

Three Interaction Patterns on Asynchronous Online Discussion Behaviours: A Methodological Comparison

ERIC Educational Resources Information Center

Jo, I.; Park, Y.; Lee, H.

2017-01-01

An asynchronous online discussion (AOD) is one format of instructional methods that facilitate student-centered learning. In the wealth of AOD research, this study evaluated how students' behavior on AOD influences their academic outcomes. This case study compared the differential analytic methods including web log mining, social network analysis…

Microbial infection affects egg viability and incubation behavior in a tropical passerine.

Treesearch

Mark I. Cook; Steven R. Beissinger; Gary A. Toranzos; Roberto A. Arendt Rodriguez

2004-01-01

Many avian species initiate incubation before clutch completion, which causes eggs to hatch asynchronously. This influences brood competitive dynamics and often results in nestling mortality. The prevailing hypotheses contend that parents incubate early because asynchronous hatching provides fitness benefits to parents or surviving offspring. An alternative idea is...

FIFO Buffer for Asynchronous Data Streams

NASA Technical Reports Server (NTRS)

Bascle, K. P.

1985-01-01

Variable-rate, asynchronous data signals from up to four measuring instruments or other sources combined in first-in/first-out (FIFO) buffer for transmission on single channel. Constructed in complementary metal-oxide-semiconductor (CMOS) logic, buffer consumes low power (only 125 mW at 5V) and conforms to aerospace standards of reliability and maintainability.

Critical Thinking in Asynchronous Online Discussion: An Investigation of Student Facilitation Techniques

ERIC Educational Resources Information Center

Lim, Sze Chung Raymond; Cheung, Wing Sum; Hew, Khe Foon

2011-01-01

Background: In the last decade, asynchronous online discussion forums have become a primary focus of many educational researchers. Some advocates believed that the process of typing out messages in itself can promote in-depth critical thinking skills. Nevertheless, empirical research has not provided much support for this claim in natural…

Interaction and Cognition in Asynchronous Computer Conferencing

ERIC Educational Resources Information Center

Schrire, Sarah

2004-01-01

This paper is based on a multiple-case study of the learning process in three asynchronous computer conferences. The conferences were part of the distance learning component in doctoral degree courses in computing technology in education offered at an American university. The conferences were analyzed from a number of perspectives, the emphasis in…

Socially Shared Metacognitive Regulation in Asynchronous CSCL in Science: Functions, Evolution and Participation

ERIC Educational Resources Information Center

Iiskala, Tuike; Volet, Simone; Lehtinen, Erno; Vauras, Marja

2015-01-01

The significance of socially shared metacognitive regulation (SSMR) in collaborative learning is gaining momentum. To date, however, there is still a paucity of research of how SSMR is manifested in asynchronous computer-supported collaborative learning (CSCL), and hardly any systematic investigation of SSMR's functions and evolution across…

The Effects of Self-Generated Synchronous and Asynchronous Visual Speech Feedback on Overt Stuttering Frequency

ERIC Educational Resources Information Center

Snyder, Gregory J.; Hough, Monica Strauss; Blanchet, Paul; Ivy, Lennette J.; Waddell, Dwight

2009-01-01

Purpose: Relatively recent research documents that visual choral speech, which represents an externally generated form of synchronous visual speech feedback, significantly enhanced fluency in those who stutter. As a consequence, it was hypothesized that self-generated synchronous and asynchronous visual speech feedback would likewise enhance…

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

ERIC Educational Resources Information Center

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…

Asynchronous Education: A Blueprint for the Future of Adult Learning.

ERIC Educational Resources Information Center

Krueger, Lyle L.; Porter, Cyndi Wilson; Burke, Daniel

While the distance learning curriculum at Lakeland College (Wisconsin) began 20 years ago, the idea for Lakeland Online was conceived about two and one-half years ago. A variety of delivery modes were considered before discovering Convene software. Since the communication process enabled by the Convene software is asynchronous and requires only a…

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

ERIC Educational Resources Information Center

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,…

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

ERIC Educational Resources Information Center

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…

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

DTIC Science & Technology

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

Reflections of Students in Their Use of Asynchronous Online Seminars

ERIC Educational Resources Information Center

Groves, Mark; O'Donoghue, John

2009-01-01

This paper reports on research that has been carried out into the use, process, and effectiveness of an asynchronous online seminar within an undergraduate sports studies degree programme. Contemporary sources are used to justify the use of technology supported learning (TSL) in higher education and to inform a reflective and critical account of…

Using Asynchronous Electronic Surveys to Help In-Class Revision: A Case Study

ERIC Educational Resources Information Center

Tong, Vincent C. H.

2012-01-01

Synchronous e-voting systems (commonly known as "clickers") have become increasingly popular as they can be used to enhance interactivity in lectures. Asynchronous electronic surveys (AESs), unlike these voting system, usually serve as a method of gathering feedback before or after teaching sessions. This paper describes and evaluates a project…

Argumentation in a Multi Party Asynchronous Computer Mediated Conference: A Generic Analysis

ERIC Educational Resources Information Center

Coffin, Caroline; Painter, Clare; Hewings, Ann

2005-01-01

This paper draws on systemic functional linguistic genre analysis to illuminate the way in which post graduate applied linguistics students structure their argumentation within a multi party asynchronous computer mediated conference. Two conference discussions within the same postgraduate course are compared in order to reveal the way in which…

The Socratic Dialogue in Asynchronous Online Discussions: Is Constructivism Redundant?

ERIC Educational Resources Information Center

Kingsley, Paul

2011-01-01

Purpose: This paper aims to examine Socratic dialogue in asynchronous online discussions in relation to constructivism. The links between theory and practice in teaching are to be discussed whilst tracing the origins of Socratic dialogue and recent trends and use of seminar in research based institutions. Design/methodology/approach: Many online…

Asynchronous Online Peer Assistance: Telephone Messages of Encouragement in Post Licensure Nursing Programs

ERIC Educational Resources Information Center

Melrose, Sherri; Swettenham, Steve

2012-01-01

Peer assistance activities can strengthen online learning environments. And yet, like other professional adult learners, working post licensure nurses attending university part time to upgrade their credentials may have limited interest in student-to-student interaction. Some intentionally choose asynchronous self-paced courses so they can work on…

Thematic Analysis of the "Games" Students Play in Asynchronous Learning Environments

ERIC Educational Resources Information Center

MacMillan, Thalia; Forte, Michele; Grant, Cynthia

2014-01-01

The dynamics of the student-student relationship within the asynchronous online classroom, as evidenced by conversations in an online discussion board, is a balancing act potentially more complex than those occurring in real-time. In order for learning to truly be considered effective, a collaborative, safe environment needs to exist among…

Scaffolding Collaborative Argumentation in Asynchronous Discussions with Message Constraints and Message Labels

ERIC Educational Resources Information Center

Jeong, Allan; Joung, Sunyoung

2007-01-01

This study examined the effects of message constraints and labels on collaborative argumentation in asynchronous online discussions. Thirty-eight undergraduate students in an introductory educational technology course were assigned to one of three groups. In one group, students posted specific types of messages using a prescribed set of message…

Flipping the Online Classroom with Web 2.0: The Asynchronous Workshop

ERIC Educational Resources Information Center

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…

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

ERIC Educational Resources Information Center

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'…

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

ERIC Educational Resources Information Center

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…

Asynchronous Computer-Mediated Corrective Feedback and the Correct Use of Prepositions: Is It Really Effective?

ERIC Educational Resources Information Center

Hosseini, Seyyed Behrooz

2012-01-01

An area that has recently attracted increasing attention is providing feedback on learners' writing accuracy through the Internet. However, research in this area has largely focused on synchronous communication, i.e., chatting, with fewer studies assessing asynchronous technologies, i.e., e-mailing. Therefore, this study investigates the…

The Role of Technology-Based Scaffolding in Problem-Based Online Asynchronous Discussion

ERIC Educational Resources Information Center

Ak, Serife

2016-01-01

This study examined the effects of technology-based scaffolds that were composed through the use of the seven-stage, problem-based learning strategy on knowledge construction in a problem-based online asynchronous discussion. In a quasi-experimental setting, 60 students in an undergraduate Instructional Technology and Material Design course were…

Superconducting magnetic energy storage for asynchronous electrical systems

DOEpatents

Boenig, H.J.

1984-05-16

It is an object of the present invention to provide superconducting magnetic energy storage for a plurality of asynchronous electrical systems. It is a further object of the present invention to provide load leveling and stability improvement in a plurality of independent ac systems using a single superconducting magnetic energy storage coil.

Factors Affecting Pre-Service Teachers' Participation in Asynchronous Discussion: The Case of Iran

ERIC Educational Resources Information Center

Ebrahimi, Alice; Faghih, Esmail; Marandi, Seyyedeh Susan

2016-01-01

This study reports on a qualitative small-scale exploratory study which examined the factors influencing 32 Iranian pre-service language teachers' participation in online asynchronous text-based discussion forums. By adopting a multiple case study design and analysing data gathered through semi-structured interviews and participants' online…

A Dynamic Analysis of the Interplay between Asynchronous and Synchronous Communication in Online Learning: The Impact of Motivation

ERIC Educational Resources Information Center

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…

An Investigation of Assessment and Feedback Practices in Fully Asynchronous Online Undergraduate Mathematics Courses

ERIC Educational Resources Information Center

Trenholm, Sven; Alcock, Lara; Robinson, Carol

2015-01-01

Research suggests it is difficult to learn mathematics in the fully asynchronous online (FAO) instructional modality, yet little is known about associated teaching and assessment practices. In this study, we investigate FAO mathematics assessment and feedback practices in particular consideration of both claims and findings that these practices…

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

ERIC Educational Resources Information Center

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…

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

ERIC Educational Resources Information Center

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…

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

ERIC Educational Resources Information Center

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…

Student Moderators in Asynchronous Online Discussion: A Question of Questions

ERIC Educational Resources Information Center

Zingaro, Daniel

2012-01-01

Much current research exalts the benefits of having students facilitate weekly discussions in asynchronous online courses. This study seeks to add to what is known about student moderation through an analysis of the types of questions students use to spur each discussion. Prior experimental work has demonstrated that the types of questions posed…

Content Analysis Coding Schemes for Online Asynchronous Discussion

ERIC Educational Resources Information Center

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…

Does the Medium Dictate the Message? Cultivating E-Communication in an Asynchronous Environment.

ERIC Educational Resources Information Center

Kiernan, Mary; Thomas, Pete; Woodroffe, Mark

Virtual learning environments (VLEs) are often perceived by education establishments as an opportunity to widen access without traditional overheads. An integral part of most VLEs is asynchronous computer conferencing and on-line moderators must help students migrate quickly to the new virtual environment to minimize learning disruption. This…

An Investigation of Student Practices in Asynchronous Computer Conferencing Courses

ERIC Educational Resources Information Center

Peters, Vanessa L.; Hewitt, Jim

2010-01-01

This study investigated the online practices of students enrolled in graduate-level distance education courses. Using interviews and a questionnaire as data sources, the study sought to: (a) identify common practices that students adopt in asynchronous discussions, and (b) gain an understanding of why students adopt them. An analysis of the data…

Asynchronous Replication and Autosome-Pair Non-Equivalence in Human Embryonic Stem Cells

PubMed Central

Dutta, Devkanya; Ensminger, Alexander W.; Zucker, Jacob P.; Chess, Andrew

2009-01-01

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. PMID:19325893

Air Temperature Distribution Measurement Using Asynchronous-Type Sound Probe

NASA Astrophysics Data System (ADS)

Katano, Yosuke; Wakatsuki, Naoto; Mizutani, Koichi

2009-07-01

In conventional temperature measurement using a sound probe, the operation beginnings of two acoustic sensors must be completely synchronized to measure time of flight (TOF), tf, because the precision of synchronization determines TOF measurement accuracy. A wireless local area network (LAN) is convenient for constructing a sensing grid; however, it causes a fluctuation in the delay of millisecond order. Therefore, it cannot provide sufficient precision for synchronizing acoustic sensors. In previous studies, synchronization was achieved by a trigger line using a coaxial cable; however, the cable reduces the flexibility of a wireless sensing grid especially in larger-scale measurement. In this study, an asynchronous-type sound probe is devised to compensate for the effect of the delay of millisecond order caused by the network. The validity of the probe was examined, and the air temperature distribution was measured using this means. A matrix method is employed to obtain the distribution. Similar results were observed using both asynchronous-type sound probes and thermocouples. This shows the validity of the use of a sensing grid with an asynchronous-type sound probe for temperature distribution measurement even if the trigger line is omitted.

Research on navigation of satellite constellation based on an asynchronous observation model using X-ray pulsar

NASA Astrophysics Data System (ADS)

Guo, Pengbin; Sun, Jian; Hu, Shuling; Xue, Ju

2018-02-01

Pulsar navigation is a promising navigation method for high-altitude orbit space tasks or deep space exploration. At present, an important reason for restricting the development of pulsar navigation is that navigation accuracy is not high due to the slow update of the measurements. In order to improve the accuracy of pulsar navigation, an asynchronous observation model which can improve the update rate of the measurements is proposed on the basis of satellite constellation which has a broad space for development because of its visibility and reliability. The simulation results show that the asynchronous observation model improves the positioning accuracy by 31.48% and velocity accuracy by 24.75% than that of the synchronous observation model. With the new Doppler effects compensation method in the asynchronous observation model proposed in this paper, the positioning accuracy is improved by 32.27%, and the velocity accuracy is improved by 34.07% than that of the traditional method. The simulation results show that without considering the clock error will result in a filtering divergence.

Asynchronous hatching and food limitation: A test of Lack's hypothesis

USGS Publications Warehouse

Skagen, Susan Knight

1988-01-01

Lack's (1954, 1968) hypothesis that asynchronous hatching of altricial birds is an adaptive response to unpredictable food shortages during the breeding season was examined in the highly granivorous Zebra Finch (Poephila guttata). I compared growth and survival of nestlings in asynchronous and artificially created synchronous broods reared under food-limited and food-abundant conditions in an aviary. I also examined the role of parental experience on survival and growth of nestlings.There was no differential mortality of Zebra Finch nestlings due to either asynchrony or food abundance. Young in abundant food treatments grew more rapidly, however, than those in food-restricted treatments. Heaviest Zebra Finch nestlings in a brood grew more quickly than their lightest siblings when food was limited, supporting Lack's hypothesis. Further, differential survival of light and heavy siblings occurred when food was abundant, suggesting that asynchronous hatching can be maladaptive under some ecological conditions. Nestlings reared by inexperienced parents suffered greater mortality and slower growth when food was abundant than nestlings raised by experienced parents. Prefledging mass was correlated with size at adulthood

Neighbor Discovery Algorithm in Wireless Local Area Networks Using Multi-beam Directional Antennas

NASA Astrophysics Data System (ADS)

Wang, Jin; Peng, Wei; Liu, Song

2017-10-01

Neighbor discovery is an important step for Wireless Local Area Networks (WLAN) and the use of multi-beam directional antennas can greatly improve the network performance. However, most neighbor discovery algorithms in WLAN, based on multi-beam directional antennas, can only work effectively in synchronous system but not in asynchro-nous system. And collisions at AP remain a bottleneck for neighbor discovery. In this paper, we propose two asynchrono-us neighbor discovery algorithms: asynchronous hierarchical scanning (AHS) and asynchronous directional scanning (ADS) algorithm. Both of them are based on three-way handshaking mechanism. AHS and ADS reduce collisions at AP to have a good performance in a hierarchical way and directional way respectively. In the end, the performance of the AHS and ADS are tested on OMNeT++. Moreover, it is analyzed that different application scenarios and the factors how to affect the performance of these algorithms. The simulation results show that AHS is suitable for the densely populated scenes around AP while ADS is suitable for that most of the neighborhood nodes are far from AP.

A formal model of asynchronous communication and its use in mechanically verifying a biphase mark protocol

NASA Technical Reports Server (NTRS)

Moore, J. Strother

1992-01-01

In this paper we present a formal model of asynchronous communication as a function in the Boyer-Moore logic. The function transforms the signal stream generated by one processor into the signal stream consumed by an independently clocked processor. This transformation 'blurs' edges and 'dilates' time due to differences in the phases and rates of the two clocks and the communications delay. The model can be used quantitatively to derive concrete performance bounds on asynchronous communications at ISO protocol level 1 (physical level). We develop part of the reusable formal theory that permits the convenient application of the model. We use the theory to show that a biphase mark protocol can be used to send messages of arbitrary length between two asynchronous processors. We study two versions of the protocol, a conventional one which uses cells of size 32 cycles and an unconventional one which uses cells of size 18. We conjecture that the protocol can be proved to work under our model for smaller cell sizes and more divergent clock rates but the proofs would be harder.

Quasi-perfect FIFO: Synchronous or asynchronous with application in controller design for the UNICON laser memory. [digital memory and buffer storage

NASA Technical Reports Server (NTRS)

Lim, R. S.

1974-01-01

The first-in-first-out memory buffer (FIFO), is an elastic digital memory whose main application is in data buffering between devices operating at different rates. Data written into the top is moved autonomously down toward the bottom of the FIFO to the lowest unoccupied location, and data read from the bottom of the FIFO will cause data from the top to move autonomously down toward the bottom. The FIFO is available in MOS LSI asynchronous form with data rate in the 1 MHz region. The FIFO described yields a simple high-speed iterative implementation, either synchronous of asynchronous. Because of this simple iterative structure, the FIFO is expandable in both number of words and bits per word, and it is attractive from the viewpoint of integrated-circuit production. For the synchronous FIFO, a model was built and successfully used in the controller for the UNICON laser memory. For the asynchronous FIFO, a model was built and also successfully used in a high-performance magnetic tape controller.

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?

PubMed

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.

Hatching behavior of eastern long-necked turtles (Chelodina longicollis): The influence of asynchronous environments on embryonic heart rate and phenotype.

PubMed

McGlashan, Jessica K; Loudon, Fiona K; Thompson, Michael B; Spencer, Ricky-John

2015-10-01

Variable temperatures within a nest cause asynchronous development within clutches of freshwater turtle embryos, yet synchronous hatching occurs and is thought to be an important survival strategy for hatchlings. Metabolic compensation and circadian rhythms in heart rates of embryonic turtles indicate the potential of communication between embryos in a nest. Heart rates were used to identify metabolic circadian rhythms in clutches of an Australian freshwater turtle (Chelodina longicollis) and determine whether embryos metabolically compensate and hatch synchronously when incubated in asynchronous environments. The effects of a group environment during incubation on egg development and incubation period were also investigated during the final 3 weeks of development. Chelodina longicollis hatch synchronously and metabolically compensate so that less advanced embryos catch up to more advanced clutch-mates. Heart rates of embryos remained stable from week 4-7 in asynchronous (M=89 bpm) and synchronous (M=92 bpm) groups and declined in the final 2 weeks of incubation (M=72 and 77 bpm). Circadian rhythms were present throughout development and diel heart rates of embryos in asynchronous groups showed less deviation from the mean (M=-0.5 bpm) than synchronous groups (M=-4 bpm). Eggs incubated in groups had a significantly shorter incubation period than eggs incubated individually. Phenotypic traits including size, performance, and growth of all hatchlings were not affected. Egg position within a turtle nest is important for coordinating development throughout incubation and facilitating synchronous hatching. Copyright © 2015 Elsevier Inc. All rights reserved.

Telemedicine for children with developmental disabilities: a more effective clinical process than office-based care.

PubMed

Langkamp, Diane L; McManus, Mark D; Blakemore, Susan D

2015-02-01

The literature on the use of telemedicine for children with developmental disabilities (DD) is limited and mostly describes telemedicine being used to link patients with distant subspecialty multidisciplinary care. Parents generally have reported satisfaction with such care and have perceived it to be equally effective as in-person care. Here we report on the use of school-based asynchronous telemedicine to connect children with DD with primary care providers. We developed Tele-Health-Kids, a school-based program using asynchronous telemedicine to connect children with DD with their primary care physician for the care of minor illnesses. We surveyed parents at enrollment and after the child's first telemedicine visit to assess satisfaction. We describe 4 cases that illustrate benefits, particularly for children with DD and challenging behaviors, suggesting that asynchronous telemedicine may actually be superior to traditional in-office visits in some circumstances. Most parents expressed a high level of satisfaction with the program. Benefits identified include decreased stress to the child and the parents as well as increasing the likelihood of a successful medical examination due to greater cooperation by the child. Visits using asynchronous or "store and forward" telemedicine technology may be superior in some situations by allowing the visit to be performed at a pace that can be adjusted to the needs of the child with DD. More research in the use of asynchronous telemedicine for children and youth with DD, particularly for children with DD and challenging behaviors, is needed.

Feasibility and safety of adenosine cardiovascular magnetic resonance in patients with MR conditional pacemaker systems at 1.5 Tesla.

PubMed

Klein-Wiele, Oliver; Garmer, Marietta; Urbien, Rhyan; Busch, Martin; Kara, Kaffer; Mateiescu, Serban; Grönemeyer, Dietrich; Schulte-Hermes, Michael; Garbrecht, Marc; Hailer, Birgit

2015-12-22

Cardiovascular Magnetic Resonance (CMR) with adenosine stress is a valuable diagnostic tool in coronary artery disease (CAD). However, despite the development of MR conditional pacemakers CMR is not yet established in clinical routine for pacemaker patients with known or suspected CAD. A possible reason is that adenosine stress perfusion for ischemia detection in CMR has not been studied in patients with cardiac conduction disease requiring pacemaker therapy. Other than under resting conditions it is unclear whether MR safe pacing modes (paused pacing or asynchronous mode) can be applied safely because the effect of adenosine on heart rate is not precisely known in this entity of patients. We investigate for the first time feasibility and safety of adenosine stress CMR in pacemaker patients in clinical routine and evaluate a pacing protocol that considers heart rate changes under adenosine. We retrospectively analyzed CMR scans of 24 consecutive patients with MR conditional pacemakers (mean age 72.1 ± 11.0 years) who underwent CMR in clinical routine for the evaluation of known or suspected CAD. MR protocol included cine imaging, adenosine stress perfusion and late gadolinium enhancement. Pacemaker indications were sinus node dysfunction (n = 18) and second or third degree AV block (n = 6). Under a pacing protocol intended to avoid competitive pacing on the one hand and bradycardia due to AV block on the other no arrhythmia occurred. Pacemaker stimulation was paused to prevent competitive pacing in sinus node dysfunction with resting heart rate >45 bpm. Sympatho-excitatory effect of adenosine led to a significant acceleration of heart rate by 12.3 ± 8.3 bpm (p < 0.001), no bradycardia occurred. On the contrary in AV block heart rate remained constant; asynchronous pacing above resting heart rate did not interfere with intrinsic rhythm. Adenosine stress CMR appears to be feasible and safe in patients with MR conditional pacemakers. Heart rate response to adenosine has to be considered for the choice of pacing modes during CMR.

"Power-on resets" in cardiac implantable electronic devices during magnetic resonance imaging.

PubMed

Higgins, John V; Sheldon, Seth H; Watson, Robert E; Dalzell, Connie; Acker, Nancy; Cha, Yong-Mei; Asirvatham, Samuel J; Kapa, Suraj; Felmlee, Joel P; Friedman, Paul A

2015-03-01

Magnetic resonance imaging (MRI) has been safely performed in some patients with cardiac implantable electronic devices (CIEDs) under careful monitoring and prespecified conditions. Pacemaker-dependent patients are often excluded, partly because of the potential for "power-on reset" (PoR), which can lead to a change from asynchronous to inhibited pacing with consequent inhibition of pacing due to electromagnetic interference during MRI. The purpose of this study was to review risk factors for PoR during MRI. A prospective study was performed between January 2008 and May 2013 in patients with CIEDs undergoing clinically indicated MRI. Eligible patients were not pacemaker dependent. Devices were interrogated before and after MRI, programmed to an asynchronous mode or an inhibition mode with tachyarrhythmia therapies turned off, and reprogrammed to their original settings after MRI. MRI scans (n = 256) were performed in 198 patients with non-MRI-conditional CIEDs between 2008 and 2013 (median age 66 years; interquartile range 57-77 years; 59% men). PoR occurred during 9 MRI scans (3.5%) in 8 patients. PoR was more frequent with Medtronic devices than with other generator brands (n = 9/139 vs 0/117 [6% vs 0%]; P = .005). Devices with PoR were all released before 2002 and were implanted from 1999 to 2004. Effects of PoR included a decrease in heart rate during MRI (n = 4) and transient anomalous battery life indication (n = 1). All devices functioned normally after MRI. PoR occurs infrequently but can cause deleterious changes in pacing mode and heart rate. MRI should not be performed in pacemaker-dependent patients with older at-risk generators. Continuous monitoring during MRI is essential because unrecognized PoR may inhibit pacing or accelerate battery depletion due to high pacing output. Copyright © 2015 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.

Spurious testosterone laboratory results in a patient taking synthetic alkaline phosphatase (asfotase alfa).

PubMed

Sofronescu, Alina G; Ross, Meredith; Rush, Eric; Goldner, Whitney

2018-04-27

We report a case of discordant total and free testosterone values in a patient with hypogonadism and juvenile hypophosphatasia after he initiated treatment with asfotase alfa, recombinant tissue non-specific alkaline phosphatase. Total testosterone was evaluated using immunoassay pre and post initiation of therapy with asfotase alfa, and free testosterone was evaluated using radioimmunoassay and LC-MS/MS while on asfotase alfa therapy. Total testosterone measured by immunoassay was normal prior to therapy with asfotase alfa, and was low post initiation of therapy. During the same time frame, free testosterone measured using RAI and total testosterone measured using LC-MS/MS were normal on asfotase alfa therapy. This suggests assay interference with the total testosterone immunoassay. When laboratory results are discordant or do not match the clinical impression, the possibility of assay interference should be considered. Alternative laboratory methods free of the interference should be selected to evaluate these patients. ALPL gene, Approved name: Alkaline phosphatase, liver/bone/kidney, Synonym: Tissue non-specific alkaline phosphatase (TNSAP). Copyright © 2018 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

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

PubMed

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.

Refining an Asynchronous Telerehabilitation Platform for Speech-Language Pathology: Engaging End-Users in the Process

PubMed Central

Hill, Annie J.; Breslin, Hugh M.

2016-01-01

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 transfer 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 3 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 feedback options to both the participant and clinician, automatic transfer of results to the clinician, and expansion of the task template list. This research highlights the importance of including end-users in the process of technology refinement, in order to ensure effective and efficient use of the technology. Future directions for research are discussed including clinical trials in which the effectiveness of and adherence to intervention protocols using asynchronous telerehabilitation are examined. PMID:28066211

Rapid Feedforward Inhibition and Asynchronous Excitation Regulate Granule Cell Activity in the Mammalian Main Olfactory Bulb

PubMed Central

Burton, Shawn D.

2015-01-01

Granule cell-mediated inhibition is critical to patterning principal neuron activity in the olfactory bulb, and perturbation of synaptic input to granule cells significantly alters olfactory-guided behavior. Despite the critical role of granule cells in olfaction, little is known about how sensory input recruits granule cells. Here, we combined whole-cell patch-clamp electrophysiology in acute mouse olfactory bulb slices with biophysical multicompartmental modeling to investigate the synaptic basis of granule cell recruitment. Physiological activation of sensory afferents within single glomeruli evoked diverse modes of granule cell activity, including subthreshold depolarization, spikelets, and suprathreshold responses with widely distributed spike latencies. The generation of these diverse activity modes depended, in part, on the asynchronous time course of synaptic excitation onto granule cells, which lasted several hundred milliseconds. In addition to asynchronous excitation, each granule cell also received synchronous feedforward inhibition. This inhibition targeted both proximal somatodendritic and distal apical dendritic domains of granule cells, was reliably recruited across sniff rhythms, and scaled in strength with excitation as more glomeruli were activated. Feedforward inhibition onto granule cells originated from deep short-axon cells, which responded to glomerular activation with highly reliable, short-latency firing consistent with tufted cell-mediated excitation. Simulations showed that feedforward inhibition interacts with asynchronous excitation to broaden granule cell spike latency distributions and significantly attenuates granule cell depolarization within local subcellular compartments. Collectively, our results thus identify feedforward inhibition onto granule cells as a core feature of olfactory bulb circuitry and establish asynchronous excitation and feedforward inhibition as critical regulators of granule cell activity. SIGNIFICANCE STATEMENT Inhibitory granule cells are involved critically in shaping odor-evoked principal neuron activity in the mammalian olfactory bulb, yet little is known about how sensory input activates granule cells. Here, we show that sensory input to the olfactory bulb evokes a barrage of asynchronous synaptic excitation and highly reliable, short-latency synaptic inhibition onto granule cells via a disynaptic feedforward inhibitory circuit involving deep short-axon cells. Feedforward inhibition attenuates local depolarization within granule cell dendritic branches, interacts with asynchronous excitation to suppress granule cell spike-timing precision, and scales in strength with excitation across different levels of sensory input to normalize granule cell firing rates. PMID:26490853

Interference in the g g → h → γ γ On-Shell Rate and the Higgs Boson Total Width

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

Campbell, John; Carena, Marcela; Harnik, Roni

We consider interference between the Higgs signal and QCD background inmore » $$gg\\rightarrow h \\rightarrow \\gamma\\gamma$$ and its effect on the on-shell Higgs rate. The existence of sizable strong phases leads to destructive interference of about 2% of the on-shell cross section in the Standard Model. This effect can be enhanced by beyond the standard model physics. In particular, since it scales differently from the usual rates, the presence of interference allows indirect limits to be placed on the Higgs width in a novel way, using on-shell rate measurements. Our study motivates further QCD calculations to reduce uncertainties. We discuss potential width-sensitive observables, both using total and differential rates and find that the HL-LHC can potentially indirectly probe widths of order tens of MeV.« less

Mirror me: Imitative responses in adults with autism.

PubMed

Schunke, Odette; Schöttle, Daniel; Vettorazzi, Eik; Brandt, Valerie; Kahl, Ursula; Bäumer, Tobias; Ganos, Christos; David, Nicole; Peiker, Ina; Engel, Andreas K; Brass, Marcel; Münchau, Alexander

2016-02-01

Dysfunctions of the human mirror neuron system have been postulated to underlie some deficits in autism spectrum disorders including poor imitative performance and impaired social skills. Using three reaction time experiments addressing mirror neuron system functions under simple and complex conditions, we examined 20 adult autism spectrum disorder participants and 20 healthy controls matched for age, gender and education. Participants performed simple finger-lifting movements in response to (1) biological finger and non-biological dot movement stimuli, (2) acoustic stimuli and (3) combined visual-acoustic stimuli with different contextual (compatible/incompatible) and temporal (simultaneous/asynchronous) relation. Mixed model analyses revealed slower reaction times in autism spectrum disorder. Both groups responded faster to biological compared to non-biological stimuli (Experiment 1) implying intact processing advantage for biological stimuli in autism spectrum disorder. In Experiment 3, both groups had similar 'interference effects' when stimuli were presented simultaneously. However, autism spectrum disorder participants had abnormally slow responses particularly when incompatible stimuli were presented consecutively. Our results suggest imitative control deficits rather than global imitative system impairments. © The Author(s) 2015.

Functional Interference Clusters in Cancer Patients With Bone Metastases: A Secondary Analysis of RTOG 9714

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

Chow, Edward, E-mail: Edward.Chow@sunnybrook.c; James, Jennifer; Barsevick, Andrea

Purpose: To explore the relationships (clusters) among the functional interference items in the Brief Pain Inventory (BPI) in patients with bone metastases. Methods: Patients enrolled in the Radiation Therapy Oncology Group (RTOG) 9714 bone metastases study were eligible. Patients were assessed at baseline and 4, 8, and 12 weeks after randomization for the palliative radiotherapy with the BPI, which consists of seven functional items: general activity, mood, walking ability, normal work, relations with others, sleep, and enjoyment of life. Principal component analysis with varimax rotation was used to determine the clusters between the functional items at baseline and the follow-up.more » Cronbach's alpha was used to determine the consistency and reliability of each cluster at baseline and follow-up. Results: There were 448 male and 461 female patients, with a median age of 67 years. There were two functional interference clusters at baseline, which accounted for 71% of the total variance. The first cluster (physical interference) included normal work and walking ability, which accounted for 58% of the total variance. The second cluster (psychosocial interference) included relations with others and sleep, which accounted for 13% of the total variance. The Cronbach's alpha statistics were 0.83 and 0.80, respectively. The functional clusters changed at week 12 in responders but persisted through week 12 in nonresponders. Conclusion: Palliative radiotherapy is effective in reducing bone pain. Functional interference component clusters exist in patients treated for bone metastases. These clusters changed over time in this study, possibly attributable to treatment. Further research is needed to examine these effects.« less

Participation in Asynchronous Online Discussion Forums Does Improve Student Learning of Gross Anatomy

ERIC Educational Resources Information Center

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…

Online-BSEE (Online Bachelor of Science in Electrical Engineering): An Asynchronous Online Electrical Engineering Degree Program with Laboratory

ERIC Educational Resources Information Center

Tang, Wendy; Westgate, Charles; Liu, Pao-Lo; Gouzman, Michael

2014-01-01

The Online Bachelor of Science in Electrical Engineering is a collaborative effort among three University Centers at SUNY (State University of New York), namely Stony Brook, Binghamton, and Buffalo. The program delivers the complete electrical engineering curriculum at the bachelor level to students online and asynchronously. Students, however,…

Reversible logic gates on Physarum Polycephalum

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

Schumann, Andrew

2015-03-10

In this paper, we consider possibilities how to implement asynchronous sequential logic gates and quantum-style reversible logic gates on Physarum polycephalum motions. We show that in asynchronous sequential logic gates we can erase information because of uncertainty in the direction of plasmodium propagation. Therefore quantum-style reversible logic gates are more preferable for designing logic circuits on Physarum polycephalum.

Use of Podcasting as an Innovative Asynchronous E-Learning Tool for Students

ERIC Educational Resources Information Center

Jalali, Alireza; Leddy, John; Gauthier, Martin; Sun, Rong; Hincke, Maxwell; Carnegie, Jacqueline

2011-01-01

Podcasting is an innovative, asynchronous communication tool. A pilot study was conducted to assess the utility of podcasting as an educational tool for undergraduate medical students. A paper-and-pencil questionnaire was developed and distributed to the 40 first-year students enrolled in the francophone stream of the medical curriculum at the…

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

ERIC Educational Resources Information Center

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…

Educational Outcomes of Synchronous and Asynchronous High School Students: A Quantitative Causal-Comparative Study of Online Algebra 1

ERIC Educational Resources Information Center

Berry, Sharon

2017-01-01

This study used a quantitative, causal-comparative design. It compared educational outcome data from online Algebra 1 courses to determine if a significant difference existed between synchronous and asynchronous students for end-of-course grades, state assessments scores, and student perceptions of their course. The study found that synchronous…

The Effectiveness of Synchronous and Asynchronous Written Corrective Feedback on Grammatical Accuracy in a Computer-Mediated Environment

ERIC Educational Resources Information Center

Shintani, Natsuko; Aubrey, Scott

2016-01-01

This study extends research on written corrective feedback (CF) by investigating how timing of CF affects grammar acquisition. Specifically, it examined the relative effects of synchronous and asynchronous CF on the accurate use of the hypothetical conditional structure. Participants were 68 intermediate-level students of English at a university…

Microanalytic Case studies of Individual Participation Patterns in an Asynchronous Online Discussion in an Undergraduate Blended Course

ERIC Educational Resources Information Center

Wise, Alyssa Friend; Perera, Nishan; Hsiao, Ying-Ting; Speer, Jennifer; Marbouti, Farshid

2012-01-01

This study presents three case studies of students' participation patterns in an online discussion to address the gap in our current understanding of how "individuals" experience asynchronous learning environments. Cases were constructed via microanalysis of log-file data, post contents, and the evolving discussion structure. The first student was…

Collaborative Learning Processes in an Asynchronous Environment: An Analysis through Discourse and Social Networks

ERIC Educational Resources Information Center

Tirado, Ramon; Aguaded, Ignacio; Hernando, Angel

2011-01-01

This article analyses an experience in collaborative learning in an asynchronous writing environment through discussion forums on a WebCt platform of the University of Huelva's virtual campus, and was part of an innovative teaching project in 2007-08. The main objectives are to describe the processes of collaborative knowledge construction and the…

Asynchronous Online Access as an Accommodation on Students with Learning Disabilities and/or Attention-Deficit Hyperactivity Disorders in Postsecondary STEM Courses

ERIC Educational Resources Information Center

Graves, Laura; Asunda, Paul A.; Plant, Stacey J.; Goad, Chester

2011-01-01

The purpose of this study was to investigate whether asynchronous online access of course recordings was beneficial to students with learning disabilities (LD) and/or Attention Deficit/Hyperactivity Disorder (ADHD) enrolled in science, technology, engineering, and mathematics (STEM) courses. Data were collected through semi-structured interviews…

Digging beneath the Surface: Analyzing the Complexity of Instructors' Participation in Asynchronous Discussion

ERIC Educational Resources Information Center

Clarke, Lane Whitney; Bartholomew, Audrey

2014-01-01

The purpose of this study was to investigate instructor participation in asynchronous discussions through an in-depth content analysis of instructors' postings and comments through the Community of Inquiry (COI) framework (Garrison et. al, 2001). We developed an analytical tool based on this framework in order to better understand what instructors…

Writer L1/L2 Status and Asynchronous Online Writing Center Feedback: Consultant Response Patterns

ERIC Educational Resources Information Center

Weirick, Joshua; Davis, Tracy; Lawson, Daniel

2017-01-01

This case study examines the differences in comments offered by asynchronous online writing center consultants to L1 and L2 speakers and examines the potential disconnects in consultant perceptions of their practice. The researchers collected and coded sample papers and interviewed participants to contextualize data from the quantitative portion…

Reconceptualising Moderation in Asynchronous Online Discussions Using Grounded Theory

ERIC Educational Resources Information Center

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…

Exploring Singapore Primary School Students' Perceptions of Chinese Asynchronous Online Discussions

ERIC Educational Resources Information Center

Chin, Wong Wan; Sum, Cheung Wing; Foon, Hew Khe

2008-01-01

Background: Asynchronous online discussion (AOD) has found widespread use in tertiary education and adult learning environment; however, there has been little research on its use in elementary school, especially in the context of the teaching of the Chinese Language. This study explores the use of AOD in a Chinese Language class in a primary…

Synchronous and Asynchronous Text-Based CMC in Educational Contexts: A Review of Recent Research

ERIC Educational Resources Information Center

Johnson, Genevieve, Marie

2006-01-01

This paper presents a review of recent research that examines the relative instructional utility of text-based synchronous and asynchronous computer-mediated communication (CMC). As a mechanism for limiting the number of studies reviewed as well as controlling for emergent technologies, only research published since 2000 was reviewed. The goal was…

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

ERIC Educational Resources Information Center

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…

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

ERIC Educational Resources Information Center

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…

Distributed Training for the Reserve Component: Remote Delivery Using Asynchronous Computer Conferencing.

ERIC Educational Resources Information Center

Hahn, H. A.; And Others

The purposes of this research were to evaluate the cost effectiveness of using Asynchronous Computer Conferencing (ACC) and to develop guidelines for effectively conducting high quality military training using ACC. The evaluation used a portion of the Engineer Officer Advanced Course (EOAC) as a test bed. Course materials which taught the same…

Interaction and Critical Inquiry in Asynchronous Computer-Mediated Conferencing: A Research Agenda

ERIC Educational Resources Information Center

Hopkins, Joseph; Gibson, Will; Ros i. Sole, Cristina; Savvides, Nicola; Starkey, Hugh

2008-01-01

This paper reviews research on learner and tutor interaction in asynchronous computer-mediated (ACM) conferences used in distance learning. The authors note claims made for the potential of ACM conferences to promote higher-order critical inquiry and the social construction of knowledge, and argue that there is a general lack of evidence regarding…

Analysis of an Asynchronous Online Discussion as a Supportive Model for Peer Collaboration and Reflection in Teacher Education

ERIC Educational Resources Information Center

Plešec Gasparic, Romina; Pecar, Mojca

2016-01-01

Professional development of future teachers is based on connecting theory and practice with the aim of supporting and developing critical, independent, responsible decision-making and active teaching. With this aim we designed a blended learning environment with an asynchronous online discussion, enabling collaboration and reflection even when…

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

ERIC Educational Resources Information Center

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…

Using Asynchronous Video to Achieve Instructor Immediacy and Closeness in Online Classes: Experiences from Three Cases

ERIC Educational Resources Information Center

Griffiths, Michael; Graham, Charles

2010-01-01

This research sought to understand the experiences of students and instructors with asynchronous video (video-mail) using webcams in three online sections of teacher education classes at Brigham Young University. We examined the experiences of students through scores and comments posted in student ratings surveys, and the experiences of…

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

ERIC Educational Resources Information Center

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,…

Asynchronous online foresight panels: the case of wildfire management

Treesearch

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...

Effects of Synchronous and Asynchronous Computer-Mediated Communication (CMC) Oral Conversations on English Language Learners' Discourse Functions

ERIC Educational Resources Information Center

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…

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

ERIC Educational Resources Information Center

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…

Student Perceptions of Asynchronous Multimodal Instructor Feedback: A Multiple Case Study

ERIC Educational Resources Information Center

Lenards, Nishele Dyan

2017-01-01

Student dissatisfaction has been a problem in higher education with regard to the provision of assessment-related feedback. Due to the distant nature of online learning, instructors are faced with many challenges in delivering quality feedback because the communication is asynchronous and lacks social cues that are present in a F2F environment.…

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

ERIC Educational Resources Information Center

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…

Three-Dimensional Temperature Field Simulation for the Rotor of an Asynchronous Motor

ERIC Educational Resources Information Center

Wang, Yanwu; Fan, Chunli; Yang, Li; Sun, Fengrui

2010-01-01

A three-dimensional heat transfer model is built according to the rotor structure of an asynchronous motor, and three-dimensional temperature fields of the rotor under different working conditions, such as the unloaded, rated loaded and that with broken rotor bars, are studied based on the finite element numerical method and experiments. The…

Bully Proofing Your Twice-Exceptional Child

ERIC Educational Resources Information Center

Mohammed, Amra

2018-01-01

Twice-exceptional (2E) students are those who demonstrate a gift or talent in one or more areas and have a disability in another area. One identifying characteristic of 2E children is asynchronous development, or the display of unusual talent or maturity in one or more areas alongside a struggle to develop in other areas. Asynchronous development…

The Effect of Asynchronous/Synchronous Approaches on English Vocabulary Achievement: A Study of Iranian EFL Learners

ERIC Educational Resources Information Center

Khodaparast, Fatemeh; Ghafournia, Narjes

2015-01-01

The contribution of computer-assisted instructional programs to language learning process has been the focus of researchers for about two decades. However, the effect of synchronous and asynchronous computer-assisted approaches of language teaching on improving L2 vocabulary has been scarcely investigated. This study explored whether synchronous,…

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

ERIC Educational Resources Information Center

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…

Synchronous and Asynchronous E-Language Learning: A Case Study of Virtual University of Pakistan

ERIC Educational Resources Information Center

Perveen, Ayesha

2016-01-01

This case study evaluated the impact of synchronous and asynchronous E-Language Learning activities (ELL-ivities) in an E-Language Learning Environment (ELLE) at Virtual University of Pakistan. The purpose of the study was to assess e-language learning analytics based on the constructivist approach of collaborative construction of knowledge. The…

Computer-Mediated Synchronous and Asynchronous Corrective Feedback Provided by Trainee Teachers to Learners of French: A Preliminary Study

ERIC Educational Resources Information Center

Vidal, Julie; Thouësny, Sylvie

2015-01-01

In this paper, we investigate whether trainee teachers' practices, with respect to multimodal feedback, differ from current research, and to what extent it may affect students' language development. More specifically, the goal of the present study is threefold: (1) it observes how trainee teachers responded, whether synchronously, asynchronously,…

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

ERIC Educational Resources Information Center

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…

Exploring Change in Graduate Students' Perceptions of Web-Based Education throughout an Asynchronous Course

ERIC Educational Resources Information Center

Timotheou, Maria Mama

2017-01-01

This paper presents the main findings of a UK study exploring graduate students' perceptions of web-based education, with a specific focus on their change over time, throughout an asynchronous course. Data were collected through online messages and interviews, and analyzed qualitatively, following content and thematic analyses. Participant pre-…

Distributed Teaching Presence and Communicative Patterns in Asynchronous Learning: Name versus Reply Networks

ERIC Educational Resources Information Center

Engel, Anna; Coll, Cesar; Bustos, Alfonso

2013-01-01

This work explores some methodological challenges in the application of Social Network Analysis (SNA) to the study of "Asynchronous Learning Networks" (ALN). Our interest in the SNA is situated within the framework of the study of Distributed Teaching Presence (DTP), understood as the exercise of educational influence, through a multi-method…

Cyber Asynchronous versus Blended Cyber Approach in Distance English Learning

ERIC Educational Resources Information Center

Ge, Zi-Gang

2012-01-01

This study aims to compare the single cyber asynchronous learning approach with the blended cyber learning approach in distance English education. Two classes of 70 students participated in this study, which lasted one semester of about four months, with one class using the blended approach for their English study and the other only using the…

Using the Community of Inquiry Model to Investigate Students' Knowledge Construction in Asynchronous Online Discussions

ERIC Educational Resources Information Center

Liu, Chien-Jen; Yang, Shu Ching

2014-01-01

This study used the Community of Inquiry (CoI) model proposed by Garrison to investigate students' level of knowledge construction in asynchronous discussions. The participants included 36 senior students (27 males) majoring in information management. The students attended 18 weeks of an online information ethics course. In this study, four types…

Comparing the Social Knowledge Construction Behavioral Patterns of Problem-Based Online Asynchronous Discussion in E/M-Learning Environments

ERIC Educational Resources Information Center

Lan, Yu-Feng; Tsai, Pei-Wei; Yang, Shih-Hsien; Hung, Chun-Ling

2012-01-01

In recent years, researchers have conducted various studies on applying wireless networking technology and mobile devices in education settings. However, research on behavioral patterns in learners' online asynchronous discussions with mobile devices is limited. The purposes of this study are to develop a mobile learning system, mobile interactive…

A Survey of Factors Contributing to Learners' "Listening" Behaviors in Asynchronous Online Discussions

ERIC Educational Resources Information Center

Wise, Alyssa Friend; Marbouti, Farshid; Hsiao, Ying-Ting; Hausknecht, Simone

2012-01-01

Sixty-seven undergraduates taking either a Blended Business Course (BBC) or an Online Education Course (OEC) were surveyed about factors influencing their "listening" behaviors in asynchronous online course discussions. These are the ways they attend to the posts made by others: which posts they open, how they engage with open posts, and…

Reflective Outcomes of Convergent and Divergent Group Tasking in the Online Learning Environment

ERIC Educational Resources Information Center

Hawkes, Mark

2007-01-01

Using collaborative critical reflection as an index, this study examines the asynchronous and face-to-face discourse of 28 suburban Chicago elementary teachers developing problem based learning (PBL) curriculum. Statistical analysis of the corpus produced by the 2 mediums shows that the asynchronous online network emerges as the medium of choice…

The Effects of Computer-Mediated Synchronous and Asynchronous Direct Corrective Feedback on Writing: A Case Study

ERIC Educational Resources Information Center

Shintani, Natsuko

2016-01-01

This case study investigated the characteristics of computer-mediated synchronous corrective feedback (SCF, provided while students wrote) and asynchronous corrective feedback (ACF, provided after students had finished writing) in an EFL writing task. The task, designed to elicit the use of the hypothetical conditional, was completed by two…

Live Synchronous Web Meetings in Asynchronous Online Courses: Reconceptualizing Virtual Office Hours

ERIC Educational Resources Information Center

Lowenthal, Patrick R.; Snelson, Chareen; Dunlap, Joanna C.

2017-01-01

Most online courses rely solely on asynchronous text-based online communication. This type of communication can foster anytime, anywhere reflection, critical thinking, and deep learning. However, it can also frustrate participants because of the lack of spontaneity and visual cues and the time it takes for conversations to develop and feedback to…

Use of a Post-Asynchronous Online Discussion Assessment to Enhance Student Critical Thinking

ERIC Educational Resources Information Center

Klisc, Chris; McGill, Tanya; Hobbs, Valerie

2017-01-01

Asynchronous online discussion (AOD) is used in many tertiary education courses, and assessing it has been shown to enhance critical thinking outcomes. There has, however, been debate on what should be assessed and how the assessment should be implemented. The most common form of assessment involves grading the individual discussion contributions,…

Asynchronous Cooperative e-Learning System and Its Evaluation

NASA Astrophysics Data System (ADS)

Eto, Kazuhiro; Miyoshi, Takumi

Much attention has been attracted to collaborative learning on an e-learning system. However, it is difficult to implement the collaborative environment to an asynchronous e-learning system since collaboration would be realized only when learners join the system at the same time. On the other hand, cooperative learning has been proposed. In this method, learners can study on their own pace without making mutual agreement but with receiving cognitive information from others. In this paper, the authors have developed the asynchronous cooperative e-learning system that provides learners' attendance and studying progress as the cognitive information. The subjective evaluation experiments show that our system is slightly inferior to the synchronous collaborative e-learning system, but it can motivate the learners more than the conventional system.

Performance evaluation of an asynchronous multisensor track fusion filter

NASA Astrophysics Data System (ADS)

Alouani, Ali T.; Gray, John E.; McCabe, D. H.

2003-08-01

Recently the authors developed a new filter that uses data generated by asynchronous sensors to produce a state estimate that is optimal in the minimum mean square sense. The solution accounts for communications delay between sensors platform and fusion center. It also deals with out of sequence data as well as latent data by processing the information in a batch-like manner. This paper compares, using simulated targets and Monte Carlo simulations, the performance of the filter to the optimal sequential processing approach. It was found that the new asynchronous Multisensor track fusion filter (AMSTFF) performance is identical to that of the extended sequential Kalman filter (SEKF), while the new filter updates its track at a much lower rate than the SEKF.

Asynchronous communication in spectral-element and discontinuous Galerkin methods for atmospheric dynamics - a case study using the High-Order Methods Modeling Environment (HOMME-homme_dg_branch)

NASA Astrophysics Data System (ADS)

Jamroz, Benjamin F.; Klöfkorn, Robert

2016-08-01

The scalability of computational applications on current and next-generation supercomputers is increasingly limited by the cost of inter-process communication. We implement non-blocking asynchronous communication in the High-Order Methods Modeling Environment for the time integration of the hydrostatic fluid equations using both the spectral-element and discontinuous Galerkin methods. This allows the overlap of computation with communication, effectively hiding some of the costs of communication. A novel detail about our approach is that it provides some data movement to be performed during the asynchronous communication even in the absence of other computations. This method produces significant performance and scalability gains in large-scale simulations.

Evaluation of three different methods of distance learning for postgraduate diagnostic imaging education: A pilot study.

PubMed

Poirier, Jean-Nicolas; Cooley, Jeffrey R; Wessely, Michelle; Guebert, Gary M; Petrocco-Napuli, Kristina

2014-10-01

Objective : The purpose of this study was to evaluate the perceived effectiveness and learning potential of 3 Web-based educational methods in a postgraduate radiology setting. Methods : Three chiropractic radiology faculty from diverse geographic locations led mini-courses using asynchronous discussion boards, synchronous Web conferencing, and asynchronous voice-over case presentations formatted for Web viewing. At the conclusion of each course, participants filled out a 14-question survey (using a 5-point Likert scale) designed to evaluate the effectiveness of each method in achieving specified course objectives and goals and their satisfaction when considering the learning potential of each method. The mean, standard deviation, and percentage agreements were tabulated. Results : Twenty, 15, and 10 participants completed the discussion board, Web conferencing, and case presentation surveys, respectively. All educational methods demonstrated a high level of agreement regarding the course objective (total mean rating >4.1). The case presentations had the highest overall rating for achieving the course goals; however, all but one method still had total mean ratings >4.0 and overall agreement levels of 70%-100%. The strongest potential for interactive learning was found with Web conferencing and discussion boards, while case presentations rated very low in this regard. Conclusions : The perceived effectiveness in achieving the course objective and goals was high for each method. Residency-based distance education may be a beneficial adjunct to current methods of training, allowing for international collaboration. When considering all aspects tested, there does not appear to be a clear advantage to any one method. Utilizing various methods may be most appropriate.

40 CFR 1065.375 - Interference verification for N2O analyzers.

Code of Federal Regulations, 2013 CFR

2013-07-01

... interference verification as follows: (1) Start, operate, zero, and span the N2O analyzer as you would before... possible to the inlet of the analyzer. For example, measure dewpoint, T dew, and absolute pressure, p total...

40 CFR 1065.375 - Interference verification for N2O analyzers.

Code of Federal Regulations, 2010 CFR

2010-07-01

... interference verification as follows: (1) Start, operate, zero, and span the N2O analyzer as you would before... possible to the inlet of the analyzer. For example, measure dewpoint, T dew, and absolute pressure, p total...

40 CFR 1065.375 - Interference verification for N2O analyzers.

Code of Federal Regulations, 2014 CFR

2014-07-01

... interference verification as follows: (1) Start, operate, zero, and span the N2O analyzer as you would before... possible to the inlet of the analyzer. For example, measure dewpoint, T dew, and absolute pressure, p total...

40 CFR 1065.375 - Interference verification for N2O analyzers.

Code of Federal Regulations, 2011 CFR

2011-07-01

... interference verification as follows: (1) Start, operate, zero, and span the N2O analyzer as you would before... possible to the inlet of the analyzer. For example, measure dewpoint, T dew, and absolute pressure, p total...

40 CFR 1065.375 - Interference verification for N2O analyzers.

Code of Federal Regulations, 2012 CFR

2012-07-01

... interference verification as follows: (1) Start, operate, zero, and span the N2O analyzer as you would before... possible to the inlet of the analyzer. For example, measure dewpoint, T dew, and absolute pressure, p total...

Psychophysiological effects of synchronous versus asynchronous music during cycling.

PubMed

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.

Benefits and Limitations of Online Instruction in Natural Science Undergraduate Liberal Arts Courses

NASA Astrophysics Data System (ADS)

Liddicoat, Joseph; Roberts, Godfrey; Liddicoat, Kendra; Porzecanski, Ana Luz; Mendez, Martin; McMullen, David

2013-04-01

Online courses in the Natural Sciences are taught three ways at New York University to undergraduate students majoring in the liberal arts and professional programs - synchronous courses in which students communicate online with the instructor and classmates in real time, asynchronous courses when faculty present course material for students to access and learn at their leisure, and hybrid or blended courses when part is taught asynchronously and part is taught face-to-face in a classroom with all students present. We have done online courses each way - Global Ecology (synchronous); Stars, Planets, and Life (synchronous and asynchronous); Darwin to DNA: An Overview of Evolution (asynchronous); Biodiversity Conservation (asynchronous); and Biology of Hunger and Population (blended). We will present the advantages and challenges we experienced teaching courses online in this fashion. Besides the advantages listed in the description for this session, another can be programmed learning that allows a set of sequential steps or a more complex branching of steps that allows students to repeat lessons multiple times to master the material. And from an academic standpoint, course content and assessment can be standardized, making it possible for each student to learn the same material. Challenges include resistance to online learning by a host of stakeholders who might be educators, students, parents, and the community. Equally challenging might be the readiness of instructors and students to teach and learn online. Student integrity issues such as plagiarism and cheating are a concern in a course taught online (Thormann and Zimmerman, 2012), so we will discuss our strategies to mitigate them.

Student Perceptions of Peer versus Instructor Facilitation of Asynchronous Online Discussions: Further Findings from Three Cases

ERIC Educational Resources Information Center

Hew, Khe Foon

2015-01-01

This study aims to extend a previous work on the role of peer facilitation of asynchronous online discussions. Specifically, in this paper I report three cases that examine students' preference for peer or instructor facilitation of online discussion forums, as well as their respective reasons for it. These three cases involved the following…

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

ERIC Educational Resources Information Center

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…

Student Voices on the Roles of Instructors in Asynchronous Learning Environments in the 21st Century

ERIC Educational Resources Information Center

Gómez-Rey, Pilar; Barbera, Elena; Fernández-Navarro, Francisco

2017-01-01

This paper determines which instructional roles and outputs are important in the 21st century from the perspective of students in asynchronous learning environments. This research work uses a literature review, in-depth interviews with experts, and a pilot study with students to define the instructors' outputs. Following this, roles are determined…

Analysis of the Relevance of Posts in Asynchronous Discussions

ERIC Educational Resources Information Center

Azevedo, Breno T.; Reategui, Eliseo; Behar, Patrícia A.

2014-01-01

This paper presents ForumMiner, a tool for the automatic analysis of students' posts in asynchronous discussions. ForumMiner uses a text mining system to extract graphs from texts that are given to students as a basis for their discussion. These graphs contain the most relevant terms found in the texts, as well as the relationships between them.…

Questions as Indicators of Ocean Literacy: Students' Online Asynchronous Discussion with a Marine Scientist

ERIC Educational Resources Information Center

Fauville, Géraldine

2017-01-01

In this article, 61 high-school students learned about ocean acidification through a virtual laboratory followed by a virtual lecture and an asynchronous discussion with a marine scientist on an online platform: VoiceThread. This study focuses on the students' development of ocean literacy when prompted to ask questions to the scientist. The…

Facing Off: Comparing an In-Person Library Orientation Lecture with an Asynchronous Online Library Orientation

ERIC Educational Resources Information Center

Gall, Dan

2014-01-01

A study to compare the effectiveness of an in-person library orientation with an online asynchronous orientation was conducted with three sections of Social Work Research Methods, a required course in the University of Iowa's Master of Social Work program. Two sections of the course received an online orientation involving short videos, text and…

Self-Efficacy for Learning Mathematics Asynchronously: Instrument Refinement and the Relationship to Mathematics Achievement

ERIC Educational Resources Information Center

Hodges, Charles; Jones, R. Caroline; Prater, Alyssa

2014-01-01

The purpose of this paper is to report the results of a two-part study. Study 1 was conducted to refine and validate a survey instrument, SELMA (Hodges, 2008), used to measure learners' self-efficacy toward learning mathematics in online or technology-intensive, asynchronous learning environments. Study 2 was conducted to investigate the…

Arguing as an Academic Purpose: The Role of Asynchronous Conferencing in Supporting Argumentative Dialogue in School and University

ERIC Educational Resources Information Center

Coffin, Caroline; Hewings, Ann; North, Sarah

2012-01-01

Learning to argue is a key academic purpose for both first and second language students. It has been claimed that computer mediated asynchronous text-based conferencing is a useful medium for developing argumentation skills (Andriessen, Baker, & Suthers, 2003). This paper reports on two research studies which explore this claim. One study focused…

Missed Opportunities for Science Learning: Unacknowledged Unscientific Arguments in Asynchronous Online and Face-To-Face Discussions

ERIC Educational Resources Information Center

Callis-Duehl, Kristine; Idsardi, Robert; Humphrey, Eve A.; Gougis, Rebekka Darner

2018-01-01

We explored the scientific argumentation that occurs among university biology students during an argumentation task implemented in two environments: face-to-face in a classroom and online in an asynchronous discussion. We observed 10 student groups, each composed of three students. Our analysis focused on how students respond to their peers'…

Effects of Synchronous Lessons on Students in an Asynchronous Online Art Course

ERIC Educational Resources Information Center

Werner, Polly D.

2011-01-01

The purpose of this study was to determine what effects synchronous instruction has on students in an asynchronous online art course. Action research was selected as the research method as it allows the researcher to study his or her own classroom in order to improve their own instruction. Data was collected for a period of one month from five…

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

ERIC Educational Resources Information Center

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…

A Quantitative Study of Faculty Perceptions and Attitudes on Asynchronous Virtual Teamwork Using the Technology Acceptance Model

ERIC Educational Resources Information Center

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…

Instructional Design and Facilitation Approaches That Promote Critical Thinking in Asynchronous Online Discussions: A Review of the Literature

ERIC Educational Resources Information Center

Schindler, Laura A.; Burkholder, Gary J.

2014-01-01

Asynchronous online discussions (AODs) are often used to promote critical thinking in online courses; however, recent research suggests that levels of critical thinking in discussions remain low. Furthermore, there is a lack of consensus in the literature about the definition of critical thinking and many of the existing studies focus on one…

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

ERIC Educational Resources Information Center

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…

An Analysis of Peer-Submitted and Peer-Reviewed Answer Rationales, in an Asynchronous Peer Instruction Based Learning Environment

ERIC Educational Resources Information Center

Bhatnagar, Sameer; Lasry, Nathaniel; Desmarais, Michel; Dugdale, Michael; Whittaker, Chris; Charles, Elizabeth S.

2015-01-01

This paper reports on an analyis of data from a novel "Peer Instruction" application, named DALITE. The Peer Instruction paradigm is well suited to take advantage of peer-input in web-based learning environments. DALITE implements an asynchronous instantiation of peer instruction: after submitting their answer to a multiple-choice…

Shifting from Obligatory Discourse to Rich Dialogue: Promoting Student Interaction in Asynchronous Threaded Discussion Postings

ERIC Educational Resources Information Center

Mooney, Mara; Southard, Sheryne; Burton, Christie H.

2014-01-01

Asynchronous online threaded discussions are widely recognized as a tool to enhance learning in the virtual classroom. While they can serve as a mechanism for reinforcing material and promoting a deeper understanding of course content, discussion boards often lack rich and dynamic dialogue, and instead serve as a field of obligatory discourse,…

How People Learn in an Asynchronous Online Learning Environment: The Relationships between Graduate Students' Learning Strategies and Learning Satisfaction

ERIC Educational Resources Information Center

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…

An Investigation of Native and Nonnative English Speakers' Levels of Written Syntactic Complexity in Asynchronous Online Discussions

ERIC Educational Resources Information Center

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…

An Exploratory, Descriptive Study of the Attitudes of Instructors and Students toward the Use of Asynchronous Online Discussion at a Female University in Saudi Arabia

ERIC Educational Resources Information Center

Alshahrani, Hamed A.; Walker, David A.

2016-01-01

This exploratory, descriptive study examined instructor and female student attitudes toward asynchronous online discussion (AOD) in Saudi Arabia. Preliminary results, derived from an attitudinal-based survey, indicated that, in aggregate, instructors and students had positive attitudes toward using AOD at a female institution of higher education…

The Influence of Collective Asynchronous Discourse Elaborated Online by Pre-Service Teachers on Their Educational Interventions in the Classroom

ERIC Educational Resources Information Center

Allaire, Stéphane

2015-01-01

Networked learning communities are growing and they offer new opportunities for reflection on practice in education. Many authors have studied the processes followed and the contents produced by such communities. On the other hand, few have observed how collective asynchronous discourse can be enacted in the classroom. This objective was pursued…

Blending Asynchronous Discussion Groups and Peer Tutoring in Higher Education: An Exploratory Study of Online Peer Tutoring Behaviour

ERIC Educational Resources Information Center

De Smet, Marijke; Van Keer, Hilde; Valcke, Martin

2008-01-01

In the present study cross-age peer tutoring was implemented in a higher education context. Fourth-year students (N=39) operated as online tutors to support freshmen in discussing cases and solving authentic problems. This study contributes to a better understanding of the supportive interventions of tutors in asynchronous discussion groups. Peer…

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

ERIC Educational Resources Information Center

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…

Global interrupt and barrier networks

DOEpatents

Blumrich, Matthias A.; Chen, Dong; Coteus, Paul W.; Gara, Alan G.; Giampapa, Mark E; Heidelberger, Philip; Kopcsay, Gerard V.; Steinmacher-Burow, Burkhard D.; Takken, Todd E.

2008-10-28

A system and method for generating global asynchronous signals in a computing structure. Particularly, a global interrupt and barrier network is implemented that implements logic for generating global interrupt and barrier signals for controlling global asynchronous operations performed by processing elements at selected processing nodes of a computing structure in accordance with a processing algorithm; and includes the physical interconnecting of the processing nodes for communicating the global interrupt and barrier signals to the elements via low-latency paths. The global asynchronous signals respectively initiate interrupt and barrier operations at the processing nodes at times selected for optimizing performance of the processing algorithms. In one embodiment, the global interrupt and barrier network is implemented in a scalable, massively parallel supercomputing device structure comprising a plurality of processing nodes interconnected by multiple independent networks, with each node including one or more processing elements for performing computation or communication activity as required when performing parallel algorithm operations. One multiple independent network includes a global tree network for enabling high-speed global tree communications among global tree network nodes or sub-trees thereof. The global interrupt and barrier network may operate in parallel with the global tree network for providing global asynchronous sideband signals.

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

PubMed

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.

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

PubMed

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.

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

PubMed Central

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

40 CFR 1065.355 - H2O and CO2 interference verification for CO NDIR analyzers.

Code of Federal Regulations, 2013 CFR

2013-07-01

... interference verification as follows: (1) Start, operate, zero, and span the CO NDIR analyzer as you would..., and absolute pressure, p total, to calculate x H2O. Verify that the water content meets the...

40 CFR 1065.355 - H2O and CO2 interference verification for CO NDIR analyzers.

Code of Federal Regulations, 2012 CFR

2012-07-01

... interference verification as follows: (1) Start, operate, zero, and span the CO NDIR analyzer as you would..., and absolute pressure, p total, to calculate x H2O. Verify that the water content meets the...

40 CFR 1065.355 - H2O and CO2 interference verification for CO NDIR analyzers.

Code of Federal Regulations, 2011 CFR

2011-07-01

... interference verification as follows: (1) Start, operate, zero, and span the CO NDIR analyzer as you would..., and absolute pressure, p total, to calculate x H2O. Verify that the water content meets the...

40 CFR 1065.355 - H2O and CO2 interference verification for CO NDIR analyzers.

Code of Federal Regulations, 2010 CFR

2010-07-01

... interference verification as follows: (1) Start, operate, zero, and span the CO NDIR analyzer as you would..., and absolute pressure, p total, to calculate x H2O. Verify that the water content meets the...

Asynchronous communication in spectral-element and discontinuous Galerkin methods for atmospheric dynamics – a case study using the High-Order Methods Modeling Environment (HOMME-homme_dg_branch)

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

Jamroz, Benjamin F.; Klofkorn, Robert

The scalability of computational applications on current and next-generation supercomputers is increasingly limited by the cost of inter-process communication. We implement non-blocking asynchronous communication in the High-Order Methods Modeling Environment for the time integration of the hydrostatic fluid equations using both the spectral-element and discontinuous Galerkin methods. This allows the overlap of computation with communication, effectively hiding some of the costs of communication. A novel detail about our approach is that it provides some data movement to be performed during the asynchronous communication even in the absence of other computations. This method produces significant performance and scalability gains in large-scalemore » simulations.« less

Asynchronous communication in spectral-element and discontinuous Galerkin methods for atmospheric dynamics – a case study using the High-Order Methods Modeling Environment (HOMME-homme_dg_branch)

DOE PAGES

Jamroz, Benjamin F.; Klofkorn, Robert

2016-08-26

The scalability of computational applications on current and next-generation supercomputers is increasingly limited by the cost of inter-process communication. We implement non-blocking asynchronous communication in the High-Order Methods Modeling Environment for the time integration of the hydrostatic fluid equations using both the spectral-element and discontinuous Galerkin methods. This allows the overlap of computation with communication, effectively hiding some of the costs of communication. A novel detail about our approach is that it provides some data movement to be performed during the asynchronous communication even in the absence of other computations. This method produces significant performance and scalability gains in large-scalemore » simulations.« less

Taming the Wild: A Unified Analysis of Hogwild!-Style Algorithms.

PubMed

De Sa, Christopher; Zhang, Ce; Olukotun, Kunle; Ré, Christopher

2015-12-01

Stochastic gradient descent (SGD) is a ubiquitous algorithm for a variety of machine learning problems. Researchers and industry have developed several techniques to optimize SGD's runtime performance, including asynchronous execution and reduced precision. Our main result is a martingale-based analysis that enables us to capture the rich noise models that may arise from such techniques. Specifically, we use our new analysis in three ways: (1) we derive convergence rates for the convex case (Hogwild!) with relaxed assumptions on the sparsity of the problem; (2) we analyze asynchronous SGD algorithms for non-convex matrix problems including matrix completion; and (3) we design and analyze an asynchronous SGD algorithm, called Buckwild!, that uses lower-precision arithmetic. We show experimentally that our algorithms run efficiently for a variety of problems on modern hardware.

Dynamic modelling and estimation of the error due to asynchronism in a redundant asynchronous multiprocessor system

NASA Technical Reports Server (NTRS)

Huynh, Loc C.; Duval, R. W.

1986-01-01

The use of Redundant Asynchronous Multiprocessor System to achieve ultrareliable Fault Tolerant Control Systems shows great promise. The development has been hampered by the inability to determine whether differences in the outputs of redundant CPU's are due to failures or to accrued error built up by slight differences in CPU clock intervals. This study derives an analytical dynamic model of the difference between redundant CPU's due to differences in their clock intervals and uses this model with on-line parameter identification to idenitify the differences in the clock intervals. The ability of this methodology to accurately track errors due to asynchronisity generate an error signal with the effect of asynchronisity removed and this signal may be used to detect and isolate actual system failures.

Propeller propulsion system integration: State of technology survey

NASA Technical Reports Server (NTRS)

Miley, S. J.; Vonlavante, E.

1985-01-01

A literature survey was performed to identify and review technical material applicable to the problem area of propeller propulsion system integration. The survey covered only aerodynamic interference aspects of the problem, and was restricted primarily to propeller effects on the airframe. The subject of airframe aerodynamic interference on the propeller was limited to the problem of vibration due to nonuniform inflow. The problem of airframe effects on propeller performance was not included. A total of 1121 references are given. The references are grouped into the subject areas of Aircraft Stability, Propulsive Efficiency, Aerodynamic Interference, Aerodynamic Interference-Propeller Vibration, and Miscellaneous.

Exploring The effects Of An online asynchronous mindfulness meditation intervention with nursing students On Stress, mood, And Cognition: A descriptive study.

PubMed

Spadaro, Kathleen C; Hunker, Diane F

2016-04-01

Nurses returning to school while working, raising families, and maintaining other roles, can experience stress, mood changes and cognition disturbance that negatively impact their academic success. To explore the effect of an online mindfulness meditation intervention with distance nursing students on stress, mood and cognition. A 24 week descriptive study. An 8 week online intervention was offered to all undergraduate and graduate nursing students, of three nursing programs of a middle-sized university in mid-Atlantic US. A total of 26 nursing students completed the study. An 8 week online, asynchronous mindfulness intervention was provided through the learning management system with a 16 week follow-up. Perceived Stress Scale (PSS), Hospital Anxiety and Depression Scale (HADS), and Attention Network Test (ANT). Stress was significantly reduced (F(2,24)=4.163, p=.019). A decreasing trend for anxiety was noted with significant difference between time points (F(1,23)=6.889, p=.015) when practice frequency was weekly to daily. Cognition: ability to shift attention, attention selection, concentration, and accuracy improved. Findings from this study may illuminate the usefulness of a mindfulness based stress reduction program offered to distance nursing students. Further studies are needed to better demonstrate the effectiveness of the intervention. Copyright © 2016 Elsevier Ltd. All rights reserved.

Use of the superpopulation approach to estimate breeding population size: An example in asynchronously breeding birds

USGS Publications Warehouse

Williams, K.A.; Frederick, P.C.; Nichols, J.D.

2011-01-01

Many populations of animals are fluid in both space and time, making estimation of numbers difficult. Much attention has been devoted to estimation of bias in detection of animals that are present at the time of survey. However, an equally important problem is estimation of population size when all animals are not present on all survey occasions. Here, we showcase use of the superpopulation approach to capture-recapture modeling for estimating populations where group membership is asynchronous, and where considerable overlap in group membership among sampling occasions may occur. We estimate total population size of long-legged wading bird (Great Egret and White Ibis) breeding colonies from aerial observations of individually identifiable nests at various times in the nesting season. Initiation and termination of nests were analogous to entry and departure from a population. Estimates using the superpopulation approach were 47-382% larger than peak aerial counts of the same colonies. Our results indicate that the use of the superpopulation approach to model nesting asynchrony provides a considerably less biased and more efficient estimate of nesting activity than traditional methods. We suggest that this approach may also be used to derive population estimates in a variety of situations where group membership is fluid. ?? 2011 by the Ecological Society of America.

Network Security Guideline

DTIC Science & Technology

1993-06-01

3.2.15.3 ISDN Services over the Telephone Network 3 Integrated Services Digital Network (ISDN) services are subject to the same restrictions as router...to be audited: [SYS$SYSTEM]SYS.EXE, LOGINOUT.EXE, STARTUP.COM, RIGHTSLIST.DAT [SYS$ LIBARY ] I SECURESHR.EXE [SYS$ROOT] SYSEXE.DIR, SYSLIB.DIR...quantification) of the encoded value; ASCII is normally used for asynchronous transmission. compare with digital . ASYNCHRONOUS-Data transmission that is

When Groups Decide to Use Asynchronous Online Discussions: Collaborative Learning and Social Presence under a Voluntary Participation Structure

ERIC Educational Resources Information Center

So, H.-J.

2009-01-01

The purpose of this study is to explore how groups decide to use asynchronous online discussion forums in a non-mandatory setting, and, after the group decision is made, how group members use online discussion forums to complete a collaborative learning project requiring complex data gathering and research processes. While a large body of research…

A Qualitative Analysis of African American Female High School Graduates' Perceptions of Participating in an Asynchronous Credit Recovery Program

ERIC Educational Resources Information Center

Waters, Eric L.

2010-01-01

Asynchronous online credit recovery programs have been implemented in public schools across the United States for a variety of reasons. In this case, African American female students who are deficient in course credits towards high school graduation have taken advantage of this relatively new e-programming mechanism as a means to capture course…

Effectiveness of an Asynchronous Online Module on University Students' Understanding of the Bohr Model of the Hydrogen Atom

ERIC Educational Resources Information Center

Farina, William J., Jr.; Bodzin, Alec M.

2018-01-01

Web-based learning is a growing field in education, yet empirical research into the design of high quality Web-based university science instruction is scarce. A one-week asynchronous online module on the Bohr Model of the atom was developed and implemented guided by the knowledge integration framework. The unit design aligned with three identified…

A Simple Analytical Model for Asynchronous Dense WDM/OOK Systems

DTIC Science & Technology

1994-06-01

asynchronous dense WDM systems employing an external OOK modulator. Our model is based upon a close approximation of the optical Fabry - Perot filter in the...receiver as a single-pole RC filter for signals that are bandlimitr i, & -equency band approximately equal to one sixtieth of the Fabry - Perot filter’s...4 A. INPUT SIGNAL ............................................................................................... 4 B. FABRY - PEROT FILTERED OUTPUT

Teaching Writing within the Common European Framework of Reference (CEFR): A Supplement Asynchronous Blended Learning Approach in an EFL Undergraduate Course in Egypt

ERIC Educational Resources Information Center

Shaarawy, Hanaa Youssef; Lotfy, Nohayer Esmat

2013-01-01

Based on the Common European Framework of Reference (CEFR) and following a blended learning approach (a supplement model), this article reports on a quasi-experiment where writing was taught evenly with other language skills in everyday language contexts and where asynchronous online activities were required from students to extend learning beyond…

Practical applications of digital integrated circuits. Part 2: Minimization techniques, code conversion, flip-flops, and asynchronous circuits

NASA Technical Reports Server (NTRS)

1972-01-01

Here, the 7400 line of transistor to transistor logic (TTL) devices is emphasized almost exclusively where hardware is concerned. However, it should be pointed out that the logic theory contained herein applies to all hardware. Binary numbers, simplification of logic circuits, code conversion circuits, basic flip-flop theory, details about series 54/7400, and asynchronous circuits are discussed.

Asynchronous inputs and flip-flop metastability in the CLAS trigger at CEBAF

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

Doughty, D.C. Jr.; Lemon, S.; Bonneau, P.

1993-08-01

The impact of flip-flop metastability on the pipelined trigger for the CLAS detector at CEBAF has been studied. The authors find that the newest ECL flip-flops (ECLinPS) are much faster than older families (10H) at resolving the metastable condition. This will allow their use in systems with asynchronous inputs without an extra stage of synchronizing flip-flops.

A Comparison of Classroom and Online Asynchronous Problem-Based Learning for Students Undertaking Statistics Training as Part of a Public Health Masters Degree

ERIC Educational Resources Information Center

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

2013-01-01

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…

"Picturing Them Right in Front of Me": Guidelines for Implementing Video Communication in Online and Blended Learning

ERIC Educational Resources Information Center

West, Richard E.; Jay, Jason; Armstrong, Matt; Borup, Jered

2017-01-01

We provide actionable strategies that teachers can follow when implementing asynchronous video communication and feedback in their own courses. These strategies are based on our own research over many years in the use of asynchronous video in online teaching, as well as our review of the literature, and are provided to foster greater discussion on…

An asynchronous traversal engine for graph-based rich metadata management

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

Dai, Dong; Carns, Philip; Ross, Robert B.

Rich metadata in high-performance computing (HPC) systems contains extended information about users, jobs, data files, and their relationships. Property graphs are a promising data model to represent heterogeneous rich metadata flexibly. Specifically, a property graph can use vertices to represent different entities and edges to record the relationships between vertices with unique annotations. The high-volume HPC use case, with millions of entities and relationships, naturally requires an out-of-core distributed property graph database, which must support live updates (to ingest production information in real time), low-latency point queries (for frequent metadata operations such as permission checking), and large-scale traversals (for provenancemore » data mining). Among these needs, large-scale property graph traversals are particularly challenging for distributed graph storage systems. Most existing graph systems implement a "level synchronous" breadth-first search algorithm that relies on global synchronization in each traversal step. This performs well in many problem domains; but a rich metadata management system is characterized by imbalanced graphs, long traversal lengths, and concurrent workloads, each of which has the potential to introduce or exacerbate stragglers (i.e., abnormally slow steps or servers in a graph traversal) that lead to low overall throughput for synchronous traversal algorithms. Previous research indicated that the straggler problem can be mitigated by using asynchronous traversal algorithms, and many graph-processing frameworks have successfully demonstrated this approach. Such systems require the graph to be loaded into a separate batch-processing framework instead of being iteratively accessed, however. In this work, we investigate a general asynchronous graph traversal engine that can operate atop a rich metadata graph in its native format. We outline a traversal-aware query language and key optimizations (traversal-affiliate caching and execution merging) necessary for efficient performance. We further explore the effect of different graph partitioning strategies on the traversal performance for both synchronous and asynchronous traversal engines. Our experiments show that the asynchronous graph traversal engine is more efficient than its synchronous counterpart in the case of HPC rich metadata processing, where more servers are involved and larger traversals are needed. Furthermore, the asynchronous traversal engine is more adaptive to different graph partitioning strategies.« less

An asynchronous traversal engine for graph-based rich metadata management

DOE PAGES

Dai, Dong; Carns, Philip; Ross, Robert B.; ...

2016-06-23

Rich metadata in high-performance computing (HPC) systems contains extended information about users, jobs, data files, and their relationships. Property graphs are a promising data model to represent heterogeneous rich metadata flexibly. Specifically, a property graph can use vertices to represent different entities and edges to record the relationships between vertices with unique annotations. The high-volume HPC use case, with millions of entities and relationships, naturally requires an out-of-core distributed property graph database, which must support live updates (to ingest production information in real time), low-latency point queries (for frequent metadata operations such as permission checking), and large-scale traversals (for provenancemore » data mining). Among these needs, large-scale property graph traversals are particularly challenging for distributed graph storage systems. Most existing graph systems implement a "level synchronous" breadth-first search algorithm that relies on global synchronization in each traversal step. This performs well in many problem domains; but a rich metadata management system is characterized by imbalanced graphs, long traversal lengths, and concurrent workloads, each of which has the potential to introduce or exacerbate stragglers (i.e., abnormally slow steps or servers in a graph traversal) that lead to low overall throughput for synchronous traversal algorithms. Previous research indicated that the straggler problem can be mitigated by using asynchronous traversal algorithms, and many graph-processing frameworks have successfully demonstrated this approach. Such systems require the graph to be loaded into a separate batch-processing framework instead of being iteratively accessed, however. In this work, we investigate a general asynchronous graph traversal engine that can operate atop a rich metadata graph in its native format. We outline a traversal-aware query language and key optimizations (traversal-affiliate caching and execution merging) necessary for efficient performance. We further explore the effect of different graph partitioning strategies on the traversal performance for both synchronous and asynchronous traversal engines. Our experiments show that the asynchronous graph traversal engine is more efficient than its synchronous counterpart in the case of HPC rich metadata processing, where more servers are involved and larger traversals are needed. Furthermore, the asynchronous traversal engine is more adaptive to different graph partitioning strategies.« less

Six Month In Situ High-Resolution Carbonate Chemistry and Temperature Study on a Coral Reef Flat Reveals Asynchronous pH and Temperature Anomalies.

PubMed

Kline, David I; Teneva, Lida; Hauri, Claudine; Schneider, Kenneth; Miard, Thomas; Chai, Aaron; Marker, Malcolm; Dunbar, Rob; Caldeira, Ken; Lazar, Boaz; Rivlin, Tanya; Mitchell, Brian Gregory; Dove, Sophie; Hoegh-Guldberg, Ove

2015-01-01

Understanding the temporal dynamics of present thermal and pH exposure on coral reefs is crucial for elucidating reef response to future global change. Diel ranges in temperature and carbonate chemistry parameters coupled with seasonal changes in the mean conditions define periods during the year when a reef habitat is exposed to anomalous thermal and/or pH exposure. Anomalous conditions are defined as values that exceed an empirically estimated threshold for each variable. We present a 200-day time series from June through December 2010 of carbonate chemistry and environmental parameters measured on the Heron Island reef flat. These data reveal that aragonite saturation state, pH, and pCO2 were primarily modulated by biologically-driven changes in dissolved organic carbon (DIC) and total alkalinity (TA), rather than salinity and temperature. The largest diel temperature ranges occurred in austral spring, in October (1.5 - 6.6°C) and lowest diel ranges (0.9 - 3.2°C) were observed in July, at the peak of winter. We observed large diel total pH variability, with a maximum range of 7.7 - 8.5 total pH units, with minimum diel average pH values occurring during spring and maximum during fall. As with many other reefs, the nighttime pH minima on the reef flat were far lower than pH values predicted for the open ocean by 2100. DIC and TA both increased from June (end of Fall) to December (end of Spring). Using this high-resolution dataset, we developed exposure metrics of pH and temperature individually for intensity, duration, and severity of low pH and high temperature events, as well as a combined metric. Periods of anomalous temperature and pH exposure were asynchronous on the Heron Island reef flat, which underlines the importance of understanding the dynamics of co-occurrence of multiple stressors on coastal ecosystems.

Six Month In Situ High-Resolution Carbonate Chemistry and Temperature Study on a Coral Reef Flat Reveals Asynchronous pH and Temperature Anomalies

PubMed Central

Kline, David I.; Teneva, Lida; Hauri, Claudine; Schneider, Kenneth; Miard, Thomas; Chai, Aaron; Marker, Malcolm; Dunbar, Rob; Caldeira, Ken; Lazar, Boaz; Rivlin, Tanya; Mitchell, Brian Gregory; Dove, Sophie; Hoegh-Guldberg, Ove

2015-01-01

Understanding the temporal dynamics of present thermal and pH exposure on coral reefs is crucial for elucidating reef response to future global change. Diel ranges in temperature and carbonate chemistry parameters coupled with seasonal changes in the mean conditions define periods during the year when a reef habitat is exposed to anomalous thermal and/or pH exposure. Anomalous conditions are defined as values that exceed an empirically estimated threshold for each variable. We present a 200-day time series from June through December 2010 of carbonate chemistry and environmental parameters measured on the Heron Island reef flat. These data reveal that aragonite saturation state, pH, and pCO2 were primarily modulated by biologically-driven changes in dissolved organic carbon (DIC) and total alkalinity (TA), rather than salinity and temperature. The largest diel temperature ranges occurred in austral spring, in October (1.5 – 6.6°C) and lowest diel ranges (0.9 – 3.2°C) were observed in July, at the peak of winter. We observed large diel total pH variability, with a maximum range of 7.7 – 8.5 total pH units, with minimum diel average pH values occurring during spring and maximum during fall. As with many other reefs, the nighttime pH minima on the reef flat were far lower than pH values predicted for the open ocean by 2100. DIC and TA both increased from June (end of Fall) to December (end of Spring). Using this high-resolution dataset, we developed exposure metrics of pH and temperature individually for intensity, duration, and severity of low pH and high temperature events, as well as a combined metric. Periods of anomalous temperature and pH exposure were asynchronous on the Heron Island reef flat, which underlines the importance of understanding the dynamics of co-occurrence of multiple stressors on coastal ecosystems. PMID:26039687

Efficiency assessment of shock wave therapy in patients with pelvic pain employing harmonic analysis of penile bioimpedance.

PubMed

Khodyreva, L A; Dudareva, A A; Mudraya, I S; Markosyan, T G; Revenko, S V; Kumachev, K V; Logvinov, L A

2013-06-01

In searching for novel objective methods to diagnosticate pelvic pain and assess efficiency of analgesic therapy, 37 male patients were examined prior to and after the course of extracorporeal shock wave therapy (5-10 sessions) with the waves directed to projections of prostate and/or crura and shaft of the penis. The repetition rate of mechanical pulses was 3-5 Hz. The range of energy pulse density was 0.09-0.45 mJ/mm(2). The overall number of pulses in a session was 1500-3000 in any treated zone with total energy smaller than 60 J. The applicator was relocated every other series of 300-500 pulses. Effect of the shock wave therapy was assessed according to subjective symptomatic scales: International Prostate Symptom Score, International Index of Erectile Function, Quality of Life, and nociceptive Visual Analog Scale. The objective assessment of shock wave therapy was performed with harmonic analysis of penile bioimpedance variability, which quantitatively evaluated the low-frequency rhythmic and asynchronous activities at rest as well as the total pulsatile activity of the penis. The magnitude of spectrum components of bioimpedance variations was assessed with a novel parameter, the effective impedance. The spectral parameters were measured in 16 patients prior to and after the treatment course. The corresponding control values were measured in the group of healthy patients. Prior to the shock wave therapy course, all spectrum parameters of penile bioimpedance significantly differed from the control (p<0.05). After this course, low-frequency rhythmic and the total pulsatile activity decreased to normal, while asynchronous activity remained significantly different from the normal. The novel objective physiological criteria of pelvic pain diagnostics and efficiency of its treatment reflecting the regional features of circulation and neural activity corresponded to the clinical symptom scaling prior to and after the shock wave course, and on the whole, these criteria corroborated improvement of the patient state after this therapy.

Two-dimensional correlation spectroscopic studies on coordination between organic ligands and Ni2 + ions

NASA Astrophysics Data System (ADS)

Bao, Ya-nan; Zeng, Yi-wei; Guo, Ran; Ablikim, Mesude; Shi, Hai-fang; Yang, Li-min; Yang, Zhan-lan; Xu, Yi-zhuang; Noda, Isao; Wu, Jin-guang

2018-05-01

3A2g → 3T1g(P) transition band of Ni2 + is used to probe the coordination of Ni2 +. Two-dimensional asynchronous spectra (2DCOS) are generated using the Double Asynchronous Orthogonal Sample Design (DAOSD), Asynchronous Spectrum with Auxiliary Peaks (ASAP) and Two-Trace Two-Dimensional (2T2D) approaches. Cross peaks relevant to the 3A2g → 3T1g(P) transition band of Ni2 + are utilized to probe coordination between Ni2 + and various ligands. We studied the spectral behavior of the 3A2g → 3T1g(P) transition band when Ni2 + is coordinated with ethylenediaminetetraacetic acid disodium salt (EDTA). The pattern of cross peaks in 2D asynchronous spectrum demonstrates that coordination brings about significant blue shift of the band. In addition, the absorptivity of the band increases remarkably. The interaction between Ni2 + and galactitol is also investigated. Although no clearly observable change is found on the 3A2g → 3T1g(P) transition band when galactitol is introduced, the appearance of cross peak in 2D asynchronous spectrum demonstrates that coordination indeed occurs between Ni2 + and galactitol. Furthermore, the pattern of cross peak indicates that peak position, bandwidth and absorptivity of the 3A2g → 3T1g(P) transition band of Ni(galactitol)x2 + is considerably different from those of Ni(H2O)62 +. Thus, 2DCOS is helpful to reveal subtle spectral variation, which might be helpful in shedding light on the physical-chemical nature of coordination.

Effect of hemoglobin- and Perflubron-based oxygen carriers on common clinical laboratory tests.

PubMed

Ma, Z; Monk, T G; Goodnough, L T; McClellan, A; Gawryl, M; Clark, T; Moreira, P; Keipert, P E; Scott, M G

1997-09-01

Polymerized hemoglobin solutions (Hb-based oxygen carriers; HBOCs) and a second-generation perfluorocarbon (PFC) emulsion (Perflubron) are in clinical trials as temporary oxygen carriers ("blood substitutes"). Plasma and serum samples from patients receiving HBOCs look markedly red, whereas those from patients receiving PFC appear to be lipemic. Because hemolysis and lipemia are well-known interferents in many assays, we examined the effects of these substances on clinical chemistry, immunoassay, therapeutic drug, and coagulation tests. HBOC concentrations up to 50 g/L caused essentially no interference for Na, K, Cl, urea, total CO2, P, uric acid, Mg, creatinine, and glucose values determined by the Hitachi 747 or Vitros 750 analyzers (or both) or for immunoassays of lidocaine, N-acetylprocainamide, procainamide, digoxin, phenytoin, quinidine, or theophylline performed on the Abbott AxSym or TDx. Gentamycin and vancomycin assays on the AxSym exhibited a significant positive and negative interference, respectively. Immunoassays for TSH on the Abbott IMx and for troponin I on the Dade Stratus were unaffected by HBOC at this concentration. Tests for total protein, albumin, LDH, AST, ALT, GGT, amylase, lipase, and cholesterol were significantly affected to various extents at different HBOC concentrations on the Hitachi 747 and Vitros 750. The CK-MB assay on the Stratus exhibited a negative interference at 5 g/L HBOC. HBOC interference in coagulation tests was method-dependent-fibrometer-based methods on the BBL Fibro System were free from interference, but optical-based methods on the MLA 1000C exhibited interferences at 20 g/L HBOC. A 1:20 dilution of the PFC-based oxygen carrier (600 g/L) caused no interference on any of these chemistry or immunoassay tests except for amylase and ammonia on the Vitros 750 and plasma iron on the Hitachi 747.

A Method for Dynamically Selecting the Best Frequency Hopping Technique in Industrial Wireless Sensor Network Applications

PubMed Central

Fernández de Gorostiza, Erlantz; Mabe, Jon

2018-01-01

Industrial wireless applications often share the communication channel with other wireless technologies and communication protocols. This coexistence produces interferences and transmission errors which require appropriate mechanisms to manage retransmissions. Nevertheless, these mechanisms increase the network latency and overhead due to the retransmissions. Thus, the loss of data packets and the measures to handle them produce an undesirable drop in the QoS and hinder the overall robustness and energy efficiency of the network. Interference avoidance mechanisms, such as frequency hopping techniques, reduce the need for retransmissions due to interferences but they are often tailored to specific scenarios and are not easily adapted to other use cases. On the other hand, the total absence of interference avoidance mechanisms introduces a security risk because the communication channel may be intentionally attacked and interfered with to hinder or totally block it. In this paper we propose a method for supporting the design of communication solutions under dynamic channel interference conditions and we implement dynamic management policies for frequency hopping technique and channel selection at runtime. The method considers several standard frequency hopping techniques and quality metrics, and the quality and status of the available frequency channels to propose the best combined solution to minimize the side effects of interferences. A simulation tool has been developed and used in this work to validate the method. PMID:29473910

A Method for Dynamically Selecting the Best Frequency Hopping Technique in Industrial Wireless Sensor Network Applications.

PubMed

Fernández de Gorostiza, Erlantz; Berzosa, Jorge; Mabe, Jon; Cortiñas, Roberto

2018-02-23

Industrial wireless applications often share the communication channel with other wireless technologies and communication protocols. This coexistence produces interferences and transmission errors which require appropriate mechanisms to manage retransmissions. Nevertheless, these mechanisms increase the network latency and overhead due to the retransmissions. Thus, the loss of data packets and the measures to handle them produce an undesirable drop in the QoS and hinder the overall robustness and energy efficiency of the network. Interference avoidance mechanisms, such as frequency hopping techniques, reduce the need for retransmissions due to interferences but they are often tailored to specific scenarios and are not easily adapted to other use cases. On the other hand, the total absence of interference avoidance mechanisms introduces a security risk because the communication channel may be intentionally attacked and interfered with to hinder or totally block it. In this paper we propose a method for supporting the design of communication solutions under dynamic channel interference conditions and we implement dynamic management policies for frequency hopping technique and channel selection at runtime. The method considers several standard frequency hopping techniques and quality metrics, and the quality and status of the available frequency channels to propose the best combined solution to minimize the side effects of interferences. A simulation tool has been developed and used in this work to validate the method.

40 CFR 1065.355 - H2O and CO2 interference verification for CO NDIR analyzers.

Code of Federal Regulations, 2014 CFR

2014-07-01

... interference verification as follows: (1) Start, operate, zero, and span the CO NDIR analyzer as you would... absolute pressure, p total, to calculate x H 2 O. Verify that the H2O content meets the requirement in...

Asynchronous decision making in a memorized paddle pressing task

NASA Astrophysics Data System (ADS)

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.

Asynchronous Gossip for Averaging and Spectral Ranking

NASA Astrophysics Data System (ADS)

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.

Asynchronous State Estimation for Discrete-Time Switched Complex Networks With Communication Constraints.

PubMed

Zhang, Dan; Wang, Qing-Guo; Srinivasan, Dipti; Li, Hongyi; Yu, Li

2018-05-01

This paper is concerned with the asynchronous state estimation for a class of discrete-time switched complex networks with communication constraints. An asynchronous estimator is designed to overcome the difficulty that each node cannot access to the topology/coupling information. Also, the event-based communication, signal quantization, and the random packet dropout problems are studied due to the limited communication resource. With the help of switched system theory and by resorting to some stochastic system analysis method, a sufficient condition is proposed to guarantee the exponential stability of estimation error system in the mean-square sense and a prescribed performance level is also ensured. The characterization of the desired estimator gains is derived in terms of the solution to a convex optimization problem. Finally, the effectiveness of the proposed design approach is demonstrated by a simulation example.

The use of online discussions for post-clinical conference.

PubMed

Berkstresser, Kristie

2016-01-01

Nurse educators, at every level of pre-licensure nursing education, are charged with developing critical thinking skills within their students. Post-clinical conference is one teaching strategy that nurse educators can employ to help promote the development of critical thinking skills in pre-licensure nursing students. However, traditional face-to-face post-clinical conference is marred with issues and concerns, as identified in the nursing education literature. An alternative to face-to-face post-clinical conference, asynchronous online learning environment, mitigates the issues and concerns associated with traditional post-clinical conference. Adult learning theory supports the use of asynchronous online learning environment because the asynchronous online learning environment promotes student-centered teaching strategy in place of teacher-centered learning, which by its nature traditional face-to-face post-clinical conference tends to support. Copyright © 2015 Elsevier Ltd. All rights reserved.

Event-Based Tone Mapping for Asynchronous Time-Based Image Sensor

PubMed Central

Simon Chane, Camille; Ieng, Sio-Hoi; Posch, Christoph; Benosman, Ryad B.

2016-01-01

The asynchronous time-based neuromorphic image sensor ATIS is an array of autonomously operating pixels able to encode luminance information with an exceptionally high dynamic range (>143 dB). This paper introduces an event-based methodology to display data from this type of event-based imagers, taking into account the large dynamic range and high temporal accuracy that go beyond available mainstream display technologies. We introduce an event-based tone mapping methodology for asynchronously acquired time encoded gray-level data. A global and a local tone mapping operator are proposed. Both are designed to operate on a stream of incoming events rather than on time frame windows. Experimental results on real outdoor scenes are presented to evaluate the performance of the tone mapping operators in terms of quality, temporal stability, adaptation capability, and computational time. PMID:27642275

Bayesian operational modal analysis with asynchronous data, part I: Most probable value

NASA Astrophysics Data System (ADS)

Zhu, Yi-Chen; Au, Siu-Kui

2018-01-01

In vibration tests, multiple sensors are used to obtain detailed mode shape information about the tested structure. Time synchronisation among data channels is required in conventional modal identification approaches. Modal identification can be more flexibly conducted if this is not required. Motivated by the potential gain in feasibility and economy, this work proposes a Bayesian frequency domain method for modal identification using asynchronous 'output-only' ambient data, i.e. 'operational modal analysis'. It provides a rigorous means for identifying the global mode shape taking into account the quality of the measured data and their asynchronous nature. This paper (Part I) proposes an efficient algorithm for determining the most probable values of modal properties. The method is validated using synthetic and laboratory data. The companion paper (Part II) investigates identification uncertainty and challenges in applications to field vibration data.

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

NASA Astrophysics Data System (ADS)

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

2017-10-01

The interaction between berberine chloride and β-cyclodextrin (β-CyD) is investigated via 2D asynchronous UV-Vis spectrum. The occurrence of cross peaks around (420 nm, 420 nm) 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 420 nm band of berberine undergoes a red-shift, and its bandwidth decreases under the interaction with β-CyD. The red-shift of the 420 nm 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.

Impact of cerebrospinal fluid matrix on the detection of Alzheimer's disease with Aβ42 and influence of disease on the total-Aβ42/Aβ40 ratio.

PubMed

Slemmon, J Randall; Shapiro, Alice; Mercken, Marc; Streffer, Johannes; Romano, Gary; Andreasen, Niels; Zetterberg, Henrik; Blennow, Kaj

2015-12-01

The 42-amino acid fragment of amyloid β (Aβ1-42) in cerebrospinal fluid has continued to be important for detecting cerebral β-amyloidosis in Alzheimer's disease (AD). However, there are impediments to our ability to fully understand this measurement, including matrix interference and changes linked to apolipoprotein E (APOE) ε4 genotype. This study investigated matrix interference as a contributing factor for detecting AD in APOE ε4-negative patients by comparing total extractable Aβ1-42 to free Aβ1-42. It also examined the ratio of total Aβ1-42 to Aβ1-40, since changes relative to other Aβ peptides may provide a measurement of cerebral β-amyloidosis that is neutral to changes in APP metabolism. Total Aβ1-42 lost the diagnostic power for detecting AD, confirming a role for matrix in the diagnostic. However, when total Aβ1-42/Aβ1-40 was examined, the separation between groups was reestablished. This result was confirmed in a second sample set of unknown APOE status. These results confirmed that matrix interference in some cerebrospinal fluid samples appears to contribute to identifying AD patients and this can be compensated by using a total extracted Aβ1-42/Aβ1-40 ratio when matrix interference is small. It may be preferable to employ a total Aβ1-42/Aβ1-40 measurement, since this could minimize variability because of matrix and compensate for across patient differences. Aβ1-42 measurement in CSF has provided an important tool for early detection of AD. However, it appears that most assays measure a free fraction of Aβ1-42. This study examined total extracted Aβ1-42, since this would provide a more accurate assessment of Aβ1-42 in AD CSF. Total Aβ1-42 measurements alone were not good for detecting AD but total Aβ1-42/Aβ1-40 performed well. © 2015 International Society for Neurochemistry.

Technologies That Assist in Online Group Work: A Comparison of Synchronous and Asynchronous Computer Mediated Communication Technologies on Students' Learning and Community

ERIC Educational Resources Information Center

Rockinson-Szapkiw, Amanda; Wendt, Jillian

2015-01-01

While the benefits of online group work completed using asynchronous CMC technology is documented, researchers have identified a number of challenges that result in ineffective and unsuccessful online group work. Fewer channels of communication and lack of immediacy when compared to face-to-face group work are a few of the noted limitations. Thus,…

Overview of AMS (CCSDS Asynchronous Message Service)

NASA Technical Reports Server (NTRS)

Burleigh, Scott

2006-01-01

This viewgraph presentation gives an overview of the Consultative Committee for Space Data Systems (CCSDS) Asynchronous Message Service (AMS). The topics include: 1) Key Features; 2) A single AMS continuum; 3) The AMS Protocol Suite; 4) A multi-continuum venture; 5) Constraining transmissions; 6) Security; 7) Fault Tolerance; 8) Performance of Reference Implementation; 9) AMS vs Multicast (1); 10) AMS vs Multicast (2); 11) RAMS testing exercise; and 12) Results.

A Study on Run Time Assurance for Complex Cyber Physical Systems

DTIC Science & Technology

2013-04-18

safety verification approach was applied to synchronization of distributed local clocks of the nodes on a CAN bus by Jiang et al. [36]. The class of...mode of interaction between the instrumented system and the checker, we distin- guish between synchronous and asynchronous monitoring. In synchronous ...occurred. Synchronous monitoring may deliver a higher degree of assurance than the asynchronous one, because it can block a dangerous action. However

Asynchronous inputs and flip-flop metastability in the CLAS trigger at CEBAF

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

Dave Doughty; S. Lemon; P. Bonneau

1992-10-01

The impact of flip-flop metastability on the pipelined trigger for the CLAS detector at CEBAF (Continuous Electron Beam Accelerator Facility) has been studied. It is found that the newest ECL (emitter coupled logic) flip-flops (ECLinPS) are much faster than older families at resolving the metastable condition. This will allow their use in systems with asynchronous inputs without an extra stage of synchronizing flip-flops.

TACS Central Control Facility.

DTIC Science & Technology

1981-02-12

PULSE RTC REAL TIME CLOCK -{> I . SIGNAL INVERSION UASC UNIVERSAL ASYNCHRONOUS SERIAL - ---- 4w SPECIAL INTERFACE CONTROLLER Fiq. 2-1. MAC hardware...34 Universal Asynchronous Serial Controller" (UASC) cards. The cards implement an RS-232 standard interface. All controllers are set to operate at a data...Bridwell and I. Richer, "A Preliminary Design of a TDMA System for FLEETSAT," Technical Note 1975-5, Lincoln Laboratory, M.I.T. (12 March 1975), DDC

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

PubMed

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

Pseudo Asynchronous Level Crossing adc for ecg Signal Acquisition.

PubMed

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.

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

PubMed

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.

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

NASA Astrophysics Data System (ADS)

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.

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

NASA Technical Reports Server (NTRS)

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.

Effect of music-movement synchrony on exercise oxygen consumption.

PubMed

Bacon, C J; Myers, T R; Karageorghis, C I

2012-08-01

Past research indicates that endurance is improved when exercise movements are synchronised with a musical beat, however it is unclear whether such benefits are associated with reduced metabolic cost. We compared oxygen consumption (.VO2) and related physiological effects of exercise conducted synchronously and asynchronously with music. Three music tracks, each recorded at three different tempi (123, 130, and 137 beats.min-1), accompanied cycle ergometry at 65 pedal revolutions.min-1. Thus three randomly-assigned experimental conditions were administered: slow tempo asynchronous, synchronous, and fast tempo asynchronous. Exercise response of .VO2, HR, and ratings of perceived exertion (RPE), to each condition was monitored in 10 untrained male participants aged 21.7±0.8 years (mean±SD) who cycled for 12 min at 70% maximal heart rate (HR). Mean .VO2 differed among conditions (P=0.008), being lower in the synchronous (1.80±0.22 L.min-1) compared to the slow tempo asynchronous condition (1.94±0.21 L.min-1; P<0.05). There was no difference in HR or RPE among conditions, although HR showed a similar trend to .VO2. The present results indicate that exercise is more efficient when performed synchronously with music than when musical tempo is slightly slower than the rate of cyclical movement.

A massively asynchronous, parallel brain

PubMed Central

Zeki, Semir

2015-01-01

Whether the visual brain uses a parallel or a serial, hierarchical, strategy to process visual signals, the end result appears to be that different attributes of the visual scene are perceived asynchronously—with colour leading form (orientation) by 40 ms and direction of motion by about 80 ms. Whatever the neural root of this asynchrony, it creates a problem that has not been properly addressed, namely how visual attributes that are perceived asynchronously over brief time windows after stimulus onset are bound together in the longer term to give us a unified experience of the visual world, in which all attributes are apparently seen in perfect registration. In this review, I suggest that there is no central neural clock in the (visual) brain that synchronizes the activity of different processing systems. More likely, activity in each of the parallel processing-perceptual systems of the visual brain is reset independently, making of the brain a massively asynchronous organ, just like the new generation of more efficient computers promise to be. Given the asynchronous operations of the brain, it is likely that the results of activities in the different processing-perceptual systems are not bound by physiological interactions between cells in the specialized visual areas, but post-perceptually, outside the visual brain. PMID:25823871

Design Improvements and Analysis of Innovative High-Level Waste Pipeline Unplugging Technologies - 12171

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

Pribanic, Tomas; Awwad, Amer; Crespo, Jairo

2012-07-01

Transferring high-level waste (HLW) between storage tanks or to treatment facilities is a common practice performed at the Department of Energy (DoE) sites. Changes in the chemical and/or physical properties of the HLW slurry during the transfer process may lead to the formation of blockages inside the pipelines resulting in schedule delays and increased costs. To improve DoE's capabilities in the event of a pipeline plugging incident, FIU has continued to develop two novel unplugging technologies: an asynchronous pulsing system and a peristaltic crawler. The asynchronous pulsing system uses a hydraulic pulse generator to create pressure disturbances at two oppositemore » inlet locations of the pipeline to dislodge blockages by attacking the plug from both sides remotely. The peristaltic crawler is a pneumatic/hydraulic operated crawler that propels itself by a sequence of pressurization/depressurization of cavities (inner tubes). The crawler includes a frontal attachment that has a hydraulically powered unplugging tool. In this paper, details of the asynchronous pulsing system's ability to unplug a pipeline on a small-scale test-bed and results from the experimental testing of the second generation peristaltic crawler are provided. The paper concludes with future improvements for the third generation crawler and a recommended path forward for the asynchronous pulsing testing. (authors)« less

Evaluation of on-line desalter-inductively coupled plasma-mass spectrometry system for determination of Cr(III), Cr(VI), and total chromium concentrations in natural water and urine samples

NASA Astrophysics Data System (ADS)

Sun, Y. C.; Lin, C. Y.; Wu, S. F.; Chung, Y. T.

2006-02-01

We have developed a simple and convenient method for the determination of Cr(III), Cr(VI), and the total chromium concentrations in natural water and urine samples that use a flow injection on-line desalter-inductively coupled plasma-mass spectrometry system. When using aqueous ammonium chloride (pH 8) as the stripping solution, the severe interference from sodium in the matrix can be eliminated prior to inductively coupled plasma-mass spectrometry measurement, and the Cr(VI) level can be determined directly. To determine the total concentration of Cr in natural water and urine samples, we used H 2O 2 or HNO 3 to decompose the organic matter and convert all chromium species into the Cr(VI) oxidation state. To overcome the spectral interference caused by the matrix chloride ion in the resulting solutions, we employed cool plasma to successfully suppress chloride-based molecular ion interference during the inductively coupled plasma-mass spectrometry measurement. By significantly eliminating interference from the cationic and anionic components in the matrices prior to the inductively coupled plasma-mass spectrometry measurement, we found that the detection limit reached 0.18 μg L - 1 (based on 3 sigma). We validated this method through the analysis of the total chromium content in two reference materials (NIST 1643c and 2670E) and through measuring the recovery in spiked samples.

Stroboscopic Interferometer for Measuring Mirror Vibrations

NASA Technical Reports Server (NTRS)

Stahl, H. Philip; Robers, Ted

2005-01-01

Stroboscopic interferometry is a technique for measuring the modes of vibration of mirrors that are lightweight and, therefore, unavoidably flexible. The technique was conceived especially for modal characterization of lightweight focusing mirror segments to be deployed in outer space; however, the technique can be applied to lightweight mirrors designed for use on Earth as well as the modal investigation of other optical and mechanical structures. To determine the modal structure of vibration of a mirror, it is necessary to excite the mirror by applying a force that varies periodically with time at a controllable frequency. The excitation can utilize sinusoidal, square, triangular, or even asynchronous waveforms. Because vibrational modes occur at specific resonant frequencies, it is necessary to perform synchronous measurements and sweep the frequency to locate the significant resonant modes. For a given mode it is possible to step the phase of data acquisition in order to capture the modal behavior over a single cycle of the resonant frequency. In order to measure interferometrically the vibrational response of the mirror at a given frequency, an interferometer must be suitably aligned with the mirror and adjustably phase-locked with the excitation signal. As in conventional stroboscopic photography, the basic idea in stroboscopic interferometry is to capture an image of the shape of a moving object (in this case, the vibrating mirror) at a specified instant of time in the vibration cycle. Adjusting the phase difference over a full cycle causes the interference fringes to vary over the full range of motion for the mode at the excitation frequency. The interference-fringe pattern is recorded as a function of the phase difference, and, from the resulting data, the surface shape of the mirror for the given mode is extracted. In addition to the interferometer and the mirror to be tested, the equipment needed for stroboscopic interferometry includes an arbitrary-function generator (that is, a signal generator), an oscilloscope, a trigger filter, and an advanced charge-coupled-device (CCD) camera. The optical components are positioned to form a pupil image of the mirror under test on the CCD chip, so that the interference pattern representative of the instantaneous mirror shape is imaged on the CCD chip.

Microdose flare protocol with interrupted follicle stimulating hormone and added androgen for poor responders--an observational pilot study.

PubMed

Mitri, Frederic; Behan, Lucy Ann; Murphy, Courtney A; Hershko-Klement, Anat; Casper, Robert F; Bentov, Yaakov

2016-01-01

To investigate whether temporarily withholding FSH and adding androgen could improve follicular response during a microdose flare protocol in women with slow follicular growth or asynchronous follicular development. Observational pilot study. University-affiliated private fertility center. Twenty-six women aged 34-47 years with poor response to stimulation or a previous cancelled IVF cycle and with slow or asynchronous follicular growth during a microdose flare cycle. For 13 women, after initiation of ovarian stimulation using the microdose flare protocol, gonadotropin administration was interrupted and transdermal testosterone gel was added for several days (4.4 ± 1.2 d) starting after cycle day 7 (mean cycle day 10 ± 2.6). FSH, E2, follicular growth, and total number of mature oocytes retrieved were determined for all of the patients. Cycle cancellation rate as well as pregnancy rate following embryo transfer were also documented when applicable. FSH levels declined (25.2 ± 6.5 to 6.8 ± 3.2 IU/L), E2 levels increased (896 ± 687 to 2,163 ± 1,667 pmol/L), and follicular growth improved significantly during gonadotropin interruption and were tracked for 2 days during this time frame. The average number of oocytes retrieved was 5.3 ± 2.6, and the ratio of mature to total oocytes was 4:5. Four of the 13 women in the interruption group conceived following frozen embryo transfer, whereas none in the control group did. The androgen-interrupted FSH protocol may improve follicular response to gonadotropins in cycles that might otherwise be cancelled. Copyright © 2016 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

Measurements of a potential interference with laser-induced fluorescence measurements of ambient OH from the ozonolysis of biogenic alkenes

NASA Astrophysics Data System (ADS)

Rickly, Pamela; Stevens, Philip S.

2018-01-01

Reactions of the hydroxyl radical (OH) play a central role in the chemistry of the atmosphere, and measurements of its concentration can provide a rigorous test of our understanding of atmospheric oxidation. Several recent studies have shown large discrepancies between measured and modeled OH concentrations in forested areas impacted by emissions of biogenic volatile organic compounds (BVOCs), where modeled concentrations were significantly lower than measurements. A potential reason for some of these discrepancies involves interferences associated with the measurement of OH using the laser-induced fluorescence-fluorescence assay by gas expansion (LIF-FAGE) technique in these environments. In this study, a turbulent flow reactor operating at atmospheric pressure was coupled to a LIF-FAGE cell and the OH signal produced from the ozonolysis of α-pinene, β-pinene, ocimene, isoprene, and 2-methyl-3-buten-2-ol (MBO) was measured. To distinguish between OH produced from the ozonolysis reactions and any OH artifact produced inside the LIF-FAGE cell, an external chemical scrubbing technique was used, allowing for the direct measurement of any interference. An interference under high ozone (between 2 × 1013 and 10 × 1013 cm-3) and BVOC concentrations (between approximately 0.1 × 1012 and 40 × 1012 cm-3) was observed that was not laser generated and was independent of the ozonolysis reaction time. For the ozonolysis of α- and β-pinene, the observed interference accounted for approximately 40 % of the total OH signal, while for the ozonolysis of ocimene the observed interference accounted for approximately 70 % of the total OH signal. Addition of acetic acid to the reactor eliminated the interference, suggesting that the source of the interference in these experiments involved the decomposition of stabilized Criegee intermediates (SCIs) inside the FAGE detection cell. Extrapolation of these measurements to ambient concentrations suggests that these interferences should be below the detection limit of the instrument.

Asynchronous Communication Scheme For Hypercube Computer

NASA Technical Reports Server (NTRS)

Madan, Herb S.

1988-01-01

Scheme devised for asynchronous-message communication system for Mark III hypercube concurrent-processor network. Network consists of up to 1,024 processing elements connected electrically as though were at corners of 10-dimensional cube. Each node contains two Motorola 68020 processors along with Motorola 68881 floating-point processor utilizing up to 4 megabytes of shared dynamic random-access memory. Scheme intended to support applications requiring passage of both polled or solicited and unsolicited messages.

Process membership in asynchronous environments

NASA Technical Reports Server (NTRS)

Ricciardi, Aleta M.; Birman, Kenneth P.

1993-01-01

The development of reliable distributed software is simplified by the ability to assume a fail-stop failure model. The emulation of such a model in an asynchronous distributed environment is discussed. The solution proposed, called Strong-GMP, can be supported through a highly efficient protocol, and was implemented as part of a distributed systems software project at Cornell University. The precise definition of the problem, the protocol, correctness proofs, and an analysis of costs are addressed.

GLRT-based array receivers for the detection of a known signal with unknown parameters corrupted by noncircular interferences

NASA Astrophysics Data System (ADS)

Chevalier, Pascal; Oukaci, Abdelkader; Delmas, Jean-Pierre

2011-12-01

The detection of a known signal with unknown parameters in the presence of noise plus interferences (called total noise) whose covariance matrix is unknown is an important problem which has received much attention these last decades for applications such as radar, satellite localization or time acquisition in radio communications. However, most of the available receivers assume a second order (SO) circular (or proper) total noise and become suboptimal in the presence of SO noncircular (or improper) interferences, potentially present in the previous applications. The scarce available receivers which take the potential SO noncircularity of the total noise into account have been developed under the restrictive condition of a known signal with known parameters or under the assumption of a random signal. For this reason, following a generalized likelihood ratio test (GLRT) approach, the purpose of this paper is to introduce and to analyze the performance of different array receivers for the detection of a known signal, with different sets of unknown parameters, corrupted by an unknown noncircular total noise. To simplify the study, we limit the analysis to rectilinear known useful signals for which the baseband signal is real, which concerns many applications.

A Motion-Based Feature for Event-Based Pattern Recognition

PubMed Central

Clady, Xavier; Maro, Jean-Matthieu; Barré, Sébastien; Benosman, Ryad B.

2017-01-01

This paper introduces an event-based luminance-free feature from the output of asynchronous event-based neuromorphic retinas. The feature consists in mapping the distribution of the optical flow along the contours of the moving objects in the visual scene into a matrix. Asynchronous event-based neuromorphic retinas are composed of autonomous pixels, each of them asynchronously generating “spiking” events that encode relative changes in pixels' illumination at high temporal resolutions. The optical flow is computed at each event, and is integrated locally or globally in a speed and direction coordinate frame based grid, using speed-tuned temporal kernels. The latter ensures that the resulting feature equitably represents the distribution of the normal motion along the current moving edges, whatever their respective dynamics. The usefulness and the generality of the proposed feature are demonstrated in pattern recognition applications: local corner detection and global gesture recognition. PMID:28101001

Implementing asyncronous collective operations in a multi-node processing system

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

Chen, Dong; Eisley, Noel A.; Heidelberger, Philip

A method, system, and computer program product are disclosed for implementing an asynchronous collective operation in a multi-node data processing system. In one embodiment, the method comprises sending data to a plurality of nodes in the data processing system, broadcasting a remote get to the plurality of nodes, and using this remote get to implement asynchronous collective operations on the data by the plurality of nodes. In one embodiment, each of the nodes performs only one task in the asynchronous operations, and each nodes sets up a base address table with an entry for a base address of a memorymore » buffer associated with said each node. In another embodiment, each of the nodes performs a plurality of tasks in said collective operations, and each task of each node sets up a base address table with an entry for a base address of a memory buffer associated with the task.« less

Programs as Polypeptides.

PubMed

Williams, Lance R

2016-01-01

Object-oriented combinator chemistry (OOCC) is an artificial chemistry with composition devices borrowed from object-oriented and functional programming languages. Actors in OOCC are embedded in space and subject to diffusion; since they are neither created nor destroyed, their mass is conserved. Actors use programs constructed from combinators to asynchronously update their own states and the states of other actors in their neighborhoods. The fact that programs and combinators are themselves reified as actors makes it possible to build programs that build programs from combinators of a few primitive types using asynchronous spatial processes that resemble chemistry as much as computation. To demonstrate this, OOCC is used to define a parallel, asynchronous, spatially distributed self-replicating system modeled in part on the living cell. Since interactions among its parts result in the construction of more of these same parts, the system is strongly constructive. The system's high normalized complexity is contrasted with that of a simple composome.

[Asynchronous asymmetry (sexual and lateral differentiation--a consequence of asynchronous evolution)].

PubMed

Geodakian, V A

1993-01-01

In the paper is presented a unified interpretation of sex differentiation and lateral asymmetry as asynchronous evolution. The operative subsystems, i.e. the male and the left hemisphere of the brain evolutionize earlier than the conservative ones, i.e. the female and the right hemisphere. New functions appear at first in males and after many generations they are transferred to females. The leading centers of their control are at first originated in the left hemisphere, then they are translocated to the right one. The criterion for functions localization in the hemisphere is their evolutionary age: new functions are controlled by the left hemisphere, old functions by the right one. Therefore the left hemisphere is socio-cultural, ethnic, the right one is biological, special. The theory explains from a single standpoint the phenomena of sex, handedness, nervous crossover, as well as many know facts, and predicts the new ones.

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

NASA Technical Reports Server (NTRS)

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.

Surface-distributed low-frequency asynchronous stimulation delays fatigue of stimulated muscles.

PubMed

Maneski, Lana Z Popović; Malešević, Nebojša M; Savić, Andrej M; Keller, Thierry; Popović, Dejan B

2013-12-01

One important reason why functional electrical stimulation (FES) has not gained widespread clinical use is the limitation imposed by rapid muscle fatigue due to non-physiological activation of the stimulated muscles. We aimed to show that asynchronous low-pulse-rate (LPR) electrical stimulation applied by multipad surface electrodes greatly postpones the occurrence of muscle fatigue compared with conventional stimulation (high pulse rate, HPR). We compared the produced force vs. time of the forearm muscles responsible for finger flexion in 2 stimulation protocols, LPR (fL = 10 Hz) and HPR (fH = 40 Hz). Surface-distributed low-frequency asynchronous stimulation (sDLFAS) doubles the time interval before the onset of fatigue (104 ± 80%) compared with conventional synchronous stimulation. Combining the performance of multipad electrodes (increased selectivity and facilitated positioning) with sDLFAS (decreased fatigue) can improve many FES applications in both the lower and upper extremities. Copyright © 2013 Wiley Periodicals, Inc.

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

PubMed

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.

Privacy Preservation in Distributed Subgradient Optimization Algorithms.

PubMed

Lou, Youcheng; Yu, Lean; Wang, Shouyang; Yi, Peng

2017-07-31

In this paper, some privacy-preserving features for distributed subgradient optimization algorithms are considered. Most of the existing distributed algorithms focus mainly on the algorithm design and convergence analysis, but not the protection of agents' privacy. Privacy is becoming an increasingly important issue in applications involving sensitive information. In this paper, we first show that the distributed subgradient synchronous homogeneous-stepsize algorithm is not privacy preserving in the sense that the malicious agent can asymptotically discover other agents' subgradients by transmitting untrue estimates to its neighbors. Then a distributed subgradient asynchronous heterogeneous-stepsize projection algorithm is proposed and accordingly its convergence and optimality is established. In contrast to the synchronous homogeneous-stepsize algorithm, in the new algorithm agents make their optimization updates asynchronously with heterogeneous stepsizes. The introduced two mechanisms of projection operation and asynchronous heterogeneous-stepsize optimization can guarantee that agents' privacy can be effectively protected.

Asynchronous Transfer Mode Quality-of-Service Testing

NASA Technical Reports Server (NTRS)

Ivancic, William D.

1998-01-01

In support of satellite-ATM interoperability, researchers at the NASA Lewis Research Center performed asynchronous transfer mode (ATM) quality-of-service experiments using MPEG-2 (ATM application layer 5, AAL5) over ATM over an emulated satellite link. The purpose of these experiments was to determine the free-space link quality necessary to use the ATM protocol to transmit high-quality multimedia information. The experimental results have been submitted to various International Telecommunications Union (ITU) study groups in order to improve and modify current standards and recommendations for the telecommunications industry. Quality-of-service parameters for Class I, stringent class requirements for ITU-T I.356 are currently being debated. The experimental results presented will help to establish these quality-of-service thresholds. This material will also be useful in the development of the ITU-R WP-4B's Draft Preliminary New Recommendation on the Transmission of Asynchronous Transfer Mode Traffic via Satellite (Rec. S.atm).

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

NASA Astrophysics Data System (ADS)

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.

Supporting Handoff in Asynchronous Collaborative Sensemaking Using Knowledge-Transfer Graphs.

PubMed

Zhao, Jian; Glueck, Michael; Isenberg, Petra; Chevalier, Fanny; Khan, Azam

2018-01-01

During asynchronous collaborative analysis, handoff of partial findings is challenging because externalizations produced by analysts may not adequately communicate their investigative process. To address this challenge, we developed techniques to automatically capture and help encode tacit aspects of the investigative process based on an analyst's interactions, and streamline explicit authoring of handoff annotations. We designed our techniques to mediate awareness of analysis coverage, support explicit communication of progress and uncertainty with annotation, and implicit communication through playback of investigation histories. To evaluate our techniques, we developed an interactive visual analysis system, KTGraph, that supports an asynchronous investigative document analysis task. We conducted a two-phase user study to characterize a set of handoff strategies and to compare investigative performance with and without our techniques. The results suggest that our techniques promote the use of more effective handoff strategies, help increase an awareness of prior investigative process and insights, as well as improve final investigative outcomes.

Regression analysis of sparse asynchronous longitudinal data.

PubMed

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.

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

PubMed

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.

Diel feeding periodicity of Ephemera simulans nymphs in summer and winter

USGS Publications Warehouse

Johnson, James H.; Ruggirello, Jack E.; Nack, Christopher C.

2012-01-01

We examined diel feeding periodicity of Ephemera simulans nymphs during summer and winter in a third-order stream in central New York. A total of 245 nymphs were collected at 4-h intervals over two 24 h periods and were immediately preserved in 80% ethanol. In the laboratory, we weighed each nymph and its digestive tract. The ratio of wet weight of the digestive tract to the total body weight at each 4-h interval was used to determine feeding periodicity. Diel feeding periodicity followed a similar pattern in summer and winter and was significantly higher at 08:00 hours. Feeding periodicity of E. simulans in Labrador Creek is asynchronous with the two most abundant fish species in the stream and may reflect predator avoidance behavior that has been shown for other mayfly species.

Interference of allelopathic rice with penoxsulam-resistant barnyardgrass.

PubMed

Yang, Xue-Fang; Kong, Chui-Hua; Yang, Xia; Li, Yong-Feng

2017-11-01

Despite increasing knowledge of allelopathic rice interference with barnyardgrass, relatively little is known about its action on herbicide-resistant barnyardgrass. The incidence of herbicide-resistant barnyardgrass is escalating in paddy fields. Knowledge of the interference of allelopathic rice with herbicide-resistant barnyardgrass and the potential mechanisms involved is warranted. Penoxsulam-resistant and -susceptible barnyardgrass biotypes were identified and segregated from a putative penoxsulam-resistant population occurring in paddy fields in China. Allelopathic rice inhibited the growth of barnyardgrass roots more than shoots, regardless of biotype. In particular, there was a stronger inhibition for resistant barnyardgrass than for susceptible barnyardgrass. Allelopathic rice significantly reduced total root length, total root area, maximum root amplitude and maximum root depth in barnyardgrass. Furthermore, the rice allelochemicals tricin and momilactone B inhibited the growth of both resistant and susceptible barnyardgrass. Compared with root contact, root segregation significantly increased inhibition of barnyardgrass with an increase in rice allelochemicals. Root exudates from barnyardgrass induced the production of rice allelochemicals, but the effect of susceptible barnyardgrass was much stronger than that of resistant barnyardgrass. Allelopathic rice can interfere with the growth of penoxsulam-resistant barnyardgrass through allelochemical-mediated root interactions. This type of allelopathic interference may provide a non-herbicidal alternative for herbicide-resistant weed management in paddy systems. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Wave-optical evaluation of interference fringes and wavefront phase in a hard-x-ray beam totally reflected by mirror optics.

PubMed

Yamauchi, Kazuto; Yamamura, Kazuya; Mimura, Hidekazu; Sano, Yasuhisa; Saito, Akira; Endo, Katsuyoshi; Souvorov, Alexei; Yabashi, Makina; Tamasaku, Kenji; Ishikawa, Tetsuya; Mori, Yuzo

2005-11-10

The intensity flatness and wavefront shape in a coherent hard-x-ray beam totally reflected by flat mirrors that have surface bumps modeled by Gaussian functions were investigated by use of a wave-optical simulation code. Simulated results revealed the necessity for peak-to-valley height accuracy of better than 1 nm at a lateral resolution near 0.1 mm to remove high-contrast interference fringes and appreciable wavefront phase errors. Three mirrors that had different surface qualities were tested at the 1 km-long beam line at the SPring-8/Japan Synchrotron Radiation Research Institute. Interference fringes faded when the surface figure was corrected below the subnanometer level to a spatial resolution close to 0.1 mm, as indicated by the simulated results.

A Wideband Satcom Based Avionics Network with CDMA Uplink and TDM Downlink

NASA Technical Reports Server (NTRS)

Agrawal, D.; Johnson, B. S.; Madhow, U.; Ramchandran, K.; Chun, K. S.

2000-01-01

The purpose of this paper is to describe some key technical ideas behind our vision of a future satcom based digital communication network for avionics applications The key features of our design are as follows: (a) Packetized transmission to permit efficient use of system resources for multimedia traffic; (b) A time division multiplexed (TDM) satellite downlink whose physical layer is designed to operate the satellite link at maximum power efficiency. We show how powerful turbo codes (invented originally for linear modulation) can be used with nonlinear constant envelope modulation, thus permitting the satellite amplifier to operate in a power efficient nonlinear regime; (c) A code division multiple access (CDMA) satellite uplink, which permits efficient access to the satellite from multiple asynchronous users. Closed loop power control is difficult for bursty packetized traffic, especially given the large round trip delay to the satellite. We show how adaptive interference suppression techniques can be used to deal with the ensuing near-far problem; (d) Joint source-channel coding techniques are required both at the physical and the data transport layer to optimize the end-to-end performance. We describe a novel approach to multiple description image encoding at the data transport layer in this paper.

Education problems and Web-based teaching: how it impacts dental educators?

PubMed

Clark, G T

2001-01-01

This article looks at six problems that vex educators and how web-based teaching might help solve them. These problems include: (1) limited access to educational content, (2) need for asynchronous access to educational content, (3) depth and diversity of educational content, (4) training in complex problem solving, (5) promotion of lifelong learning behaviors and (6) achieving excellence in education. The advantages and disadvantage of web-based educational content for each problem are discussed. The article suggests that when a poorly organized course with inaccurate and irrelevant content is placed online, it solves no problems. However some of the above issues can be partially or fully solved by hosting well-constructed teaching modules on the web. This article also reviews the literature investigating the efficacy of off-site education as compared to that provided on-site. The conclusion of this review is that teleconference-based and web-based delivery of educational content can be as effective as traditional classroom-based teaching assuming the technologic problems sometimes associated with delivering teaching content to off-site locations do not interfere in the learning process. A suggested hierarchy for rating and comparing e-learning concepts and methods is presented for consideration.

Analytical interference by monoclonal immunoglobulins on the direct bilirubin AU Beckman Coulter assay: the benefit of unsuspected diagnosis from spurious results.

PubMed

García-González, Elena; González-Tarancón, Ricardo; Aramendía, Maite; Rello, Luis

2016-08-01

Monoclonal (M) components can interfere with the direct bilirubin (D-Bil) assay on the AU Beckman Coulter instrumentation and produce spurious results, such as D-Bil values greater than total bilirubin (T-Bil) or very low/negative D-Bil values. If properly detected, this interference may uncover undiagnosed patients with monoclonal gammopathy (MG). We investigated the interference rate on the D-Bil AU assay in serum samples known to contain M proteins along with their isotype and described the protocol set up in our laboratory to help with the diagnosis of MG based on D-Bil spurious results as first indication. During a period of 4 years, 15.4% (345 of 2235) of serum samples containing M immunoglobulins produced erroneous D-Bil results, although no clear relationship between the magnitude or isotype of the M component and interference could be found. In total 22 new patients were diagnosed with MG based on the analytical artefact with the D-Bil as first indication. The D-Bil interference from MG on the Beckman AU analysers needs to be made known to laboratories in order to prevent clinical confusion and/or additional workup to explain the origin of anomalous results. Although this information may not add to the management of existing patients with serum paraproteins, it can benefit patients that have not been diagnosed with MG by triggering follow up testing to determine if M components are present.

Importance of Pain Acceptance in Relation to Headache Disability and Pain Interference in Women with Migraine and Overweight/Obesity

PubMed Central

Lillis, Jason; Thomas, J. Graham; Seng, Elizabeth K.; Lipton, Richard B.; Pavlovic, Jelena; Rathier, Lucille; Roth, Julie; O’Leary, Kevin C.; Bond, Dale S.

2018-01-01

BACKGROUND Pain acceptance involves willingness to experience pain and engaging in valued activities while pain is present. Though pain acceptance could limit both headache-related disability and pain interference in individuals with migraine, few studies have addressed this issue. The current study evaluated whether higher levels of total pain acceptance and it’s 2 subcomponents, pain willingness and activity engagement, were associated with lower levels of headache-related impairment in women who had both migraine and overweight/obesity. METHODS In this cross-sectional study, participants seeking weight loss and headache relief in the Women’s Health and Migraine (WHAM) trial completed baseline measures of pain acceptance (Chronic Pain Acceptance Questionnaire [CPAQ]), headache-related disability (Headache Impact Test-6 [HIT-6]), and pain interference (Brief Pain Inventory [BPI]). Migraine headache frequency and pain intensity were assessed daily via smartphone diary. Using CPAQ total and subcomponent (pain willingness and activity engagement) scores, headache frequency, pain intensity, and BMI as predictors in linear regression, headache-related disability and pain interference were modeled as outcomes. RESULTS On average, participants (n=126; age=38.5±8.2 years; BMI=35.3±6.6 kg/m2) reported 8.4±4.7 migraine days/month and pain intensity of 6.0±1.5 on a 0–10 scale on headache days. After correcting for multiple comparisons (adjusted α=.008), pain willingness was independently associated with both lower headache related disability (p<.001; β=−.233) and pain interference (p<.001; β= −.261). Activity engagement was not associated with headache related disability (p=.128; β= −.138) and pain interference (p=.042; β= −.154). CPAQ Total Score was not associated with headache related disability (p=.439; β=.066) and pain interference (p=.305; β=.074). Pain intensity was significantly associated with outcomes in all analyses (p’s <.001; β’s .343−.615). CONCLUSIONS Higher pain willingness, independent of degree of both migraine severity and overweight, is associated with lower headache-related disability and general pain interference in treatment-seeking women with migraine and overweight/obesity. Future studies are needed to clarify direction of causality and test whether strategies designed to help women increase pain willingness, or relinquish ineffective efforts to control pain, can improve functional outcomes in women who have migraine and overweight/obesity. PMID:28295273

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

NASA Astrophysics Data System (ADS)

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 < .05) and between online technologies self-efficacy and academic achievement (r = .50, p < .05). However, there were low correlations between self-regulated learning and academic achievement ( r = -.02, p < .05). The results of this study reflect the constructivist tenants that the student is at the center of the learning experience. Driscoll (2005) said constructivist pedagogy sees the learner as an active participant in their learning experience rather than a passive vessel to be filled with information. This study is beneficial to theorists, administrators, leaders, 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 learning to the next level.

Light curve solutions of the eccentric binaries KIC 10992733, KIC 5632781, KIC 10026136 and their out-of-eclipse variability

NASA Astrophysics Data System (ADS)

Kjurkchieva, Diana; Vasileva, Doroteya

2018-01-01

We determined the orbits and stellar parameters of three eccentric eclipsing binaries by light curve solutions of their Kepler data. KIC 10992733 and KIC 5632781 undergo total eclipses while KIC 10026136 reveals partial eclipses. The components of the targets are G and K stars. KIC 10992733 exhibited variations which were attributed to variable visibility of spot(s) on asynchronously rotating component. KIC 5632781 and KIC 1002613 reveal tidally-induced features at periastron, i.e. they might be considered as eclipsing heartbeat stars. The characteristics of the periastron features (shape, width and amplitude) confirm the theoretical predictions.

Efficient data communication protocols for wireless networks

NASA Astrophysics Data System (ADS)

Zeydan, Engin

In this dissertation, efficient decentralized algorithms are investigated for cost minimization problems in wireless networks. For wireless sensor networks, we investigate both the reduction in the energy consumption and throughput maximization problems separately using multi-hop data aggregation for correlated data in wireless sensor networks. The proposed algorithms exploit data redundancy using a game theoretic framework. For energy minimization, routes are chosen to minimize the total energy expended by the network using best response dynamics to local data. The cost function used in routing takes into account distance, interference and in-network data aggregation. The proposed energy-efficient correlation-aware routing algorithm significantly reduces the energy consumption in the network and converges in a finite number of steps iteratively. For throughput maximization, we consider both the interference distribution across the network and correlation between forwarded data when establishing routes. Nodes along each route are chosen to minimize the interference impact in their neighborhood and to maximize the in-network data aggregation. The resulting network topology maximizes the global network throughput and the algorithm is guaranteed to converge with a finite number of steps using best response dynamics. For multiple antenna wireless ad-hoc networks, we present distributed cooperative and regret-matching based learning schemes for joint transmit beanformer and power level selection problem for nodes operating in multi-user interference environment. Total network transmit power is minimized while ensuring a constant received signal-to-interference and noise ratio at each receiver. In cooperative and regret-matching based power minimization algorithms, transmit beanformers are selected from a predefined codebook to minimize the total power. By selecting transmit beamformers judiciously and performing power adaptation, the cooperative algorithm is shown to converge to pure strategy Nash equilibrium with high probability throughout the iterations in the interference impaired network. On the other hand, the regret-matching learning algorithm is noncooperative and requires minimum amount of overhead. The proposed cooperative and regret-matching based distributed algorithms are also compared with centralized solutions through simulation results.

Impact insertion of osteochondral grafts: Interference fit and central graft reduction affect biomechanics and cartilage damage.

PubMed

Su, Alvin W; Chen, Yunchan; Wailes, Dustin H; Wong, Van W; Cai, Shengqiang; Chen, Albert C; Bugbee, William D; Sah, Robert L

2018-01-01

An osteochondral graft (OCG) is an effective treatment for articular cartilage and osteochondral defects. Impact of an OCG during insertion into the osteochondral recipient site (OCR) can cause chondrocyte death and matrix damage. The aim of the present study was to analyze the effects of graft-host interference fit and a modified OCG geometry on OCG insertion biomechanics and cartilage damage. The effects of interference fit (radius of OCG - radius of OCR), loose (0.00 mm), moderate (0.05 mm), tight (0.10 mm), and of a tight fit with OCG geometry modification (central region of decreased radius), were analyzed for OCG cylinders and OCR blocks from adult bovine knee joints with an instrumented drop tower apparatus. An increasingly tight (OCG - OCR) interference fit led to increased taps for insertion, peak axial force, graft cartilage axial compression, cumulative and total energy delivery to cartilage, lower time of peak axial force, lesser graft advancement during each tap, higher total crack length in the cartilage surface, and lower chondrocyte viability. The modified OCG, with reduction of diameter in the central area, altered the biomechanical insertion variables and biological consequences to be similar to those of the moderate interference fit scenario. Micro-computed tomography confirmed structural interference between the OCR bone and both the proximal and distal bone segments of the OCGs, with the central regions being slightly separated for the modified OCGs. These results clarify OCG insertion biomechanics and mechanobiology, and introduce a simple modification of OCGs that facilitates insertion with reduced energy while maintaining a structural interference fit. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:377-386, 2018. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

WES (Waterways Experiment Station) Communications Plan for Voice and Data

DTIC Science & Technology

1989-01-01

modem on a leased line, and two wideband HDLC 56K connections not used on the Honeywell. 30. Honeywell DPS-8 configuration, as of October 1987, is as...based voice system to support additional asynchronous dial-up modem traffic. In June 1987, Dr. N. Radhakhrishnan of the WES Information Technology...voice system (PBX) and very low-speed data communications by the laboratories using 1,200/2,400-baud asynchronous modems over analog phone lines, and

Asynchronous data change notification between database server and accelerator controls system

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

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

2011-10-10

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 anymore » 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.« less

Analysis Tools for Interconnected Boolean Networks With Biological Applications.

PubMed

Chaves, Madalena; Tournier, Laurent

2018-01-01

Boolean networks with asynchronous updates are a class of logical models particularly well adapted to describe the dynamics of biological networks with uncertain measures. The state space of these models can be described by an asynchronous state transition graph, which represents all the possible exits from every single state, and gives a global image of all the possible trajectories of the system. In addition, the asynchronous state transition graph can be associated with an absorbing Markov chain, further providing a semi-quantitative framework where it becomes possible to compute probabilities for the different trajectories. For large networks, however, such direct analyses become computationally untractable, given the exponential dimension of the graph. Exploiting the general modularity of biological systems, we have introduced the novel concept of asymptotic graph , computed as an interconnection of several asynchronous transition graphs and recovering all asymptotic behaviors of a large interconnected system from the behavior of its smaller modules. From a modeling point of view, the interconnection of networks is very useful to address for instance the interplay between known biological modules and to test different hypotheses on the nature of their mutual regulatory links. This paper develops two new features of this general methodology: a quantitative dimension is added to the asymptotic graph, through the computation of relative probabilities for each final attractor and a companion cross-graph is introduced to complement the method on a theoretical point of view.

Multiple-input single-output closed-loop isometric force control using asynchronous intrafascicular multi-electrode stimulation.

PubMed

Frankel, Mitchell A; Dowden, Brett R; Mathews, V John; Normann, Richard A; Clark, Gregory A; Meek, Sanford G

2011-06-01

Although asynchronous intrafascicular multi-electrode stimulation (IFMS) can evoke fatigue-resistant muscle force, a priori determination of the necessary stimulation parameters for precise force production is not possible. This paper presents a proportionally-modulated, multiple-input single-output (MISO) controller that was designed and experimentally validated for real-time, closed-loop force-feedback control of asynchronous IFMS. Experiments were conducted on anesthetized felines with a Utah Slanted Electrode Array implanted in the sciatic nerve, either acutely or chronically ( n = 1 for each). Isometric forces were evoked in plantar-flexor muscles, and target forces consisted of up to 7 min of step, sinusoidal, and more complex time-varying trajectories. The controller was successful in evoking steps in force with time-to-peak of less than 0.45 s, steady-state ripple of less than 7% of the mean steady-state force, and near-zero steady-state error even in the presence of muscle fatigue, but with transient overshoot of near 20%. The controller was also successful in evoking target sinusoidal and complex time-varying force trajectories with amplitude error of less than 0.5 N and time delay of approximately 300 ms. This MISO control strategy can potentially be used to develop closed-loop asynchronous IFMS controllers for a wide variety of multi-electrode stimulation applications to restore lost motor function.

Semantic integration of differently asynchronous audio-visual information in videos of real-world events in cognitive processing: an ERP study.

PubMed

Liu, Baolin; Wu, Guangning; Wang, Zhongning; Ji, Xiang

2011-07-01

In the real world, some of the auditory and visual information received by the human brain are temporally asynchronous. How is such information integrated in cognitive processing in the brain? In this paper, we aimed to study the semantic integration of differently asynchronous audio-visual information in cognitive processing using ERP (event-related potential) method. Subjects were presented with videos of real world events, in which the auditory and visual information are temporally asynchronous. When the critical action was prior to the sound, sounds incongruous with the preceding critical actions elicited a N400 effect when compared to congruous condition. This result demonstrates that semantic contextual integration indexed by N400 also applies to cognitive processing of multisensory information. In addition, the N400 effect is early in latency when contrasted with other visually induced N400 studies. It is shown that cross modal information is facilitated in time when contrasted with visual information in isolation. When the sound was prior to the critical action, a larger late positive wave was observed under the incongruous condition compared to congruous condition. P600 might represent a reanalysis process, in which the mismatch between the critical action and the preceding sound was evaluated. It is shown that environmental sound may affect the cognitive processing of a visual event. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

A novel asynchronous access method with binary interfaces

PubMed Central

2008-01-01

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. PMID:18959797

Asynchronous signal-dependent non-uniform sampler

NASA Astrophysics Data System (ADS)

Can-Cimino, Azime; Chaparro, Luis F.; Sejdić, Ervin

2014-05-01

Analog sparse signals resulting from biomedical and sensing network applications are typically non-stationary with frequency-varying spectra. By ignoring that the maximum frequency of their spectra is changing, uniform sampling of sparse signals collects unnecessary samples in quiescent segments of the signal. A more appropriate sampling approach would be signal-dependent. Moreover, in many of these applications power consumption and analog processing are issues of great importance that need to be considered. In this paper we present a signal dependent non-uniform sampler that uses a Modified Asynchronous Sigma Delta Modulator which consumes low-power and can be processed using analog procedures. Using Prolate Spheroidal Wave Functions (PSWF) interpolation of the original signal is performed, thus giving an asynchronous analog to digital and digital to analog conversion. Stable solutions are obtained by using modulated PSWFs functions. The advantage of the adapted asynchronous sampler is that range of frequencies of the sparse signal is taken into account avoiding aliasing. Moreover, it requires saving only the zero-crossing times of the non-uniform samples, or their differences, and the reconstruction can be done using their quantized values and a PSWF-based interpolation. The range of frequencies analyzed can be changed and the sampler can be implemented as a bank of filters for unknown range of frequencies. The performance of the proposed algorithm is illustrated with an electroencephalogram (EEG) signal.

Interference problems for nongeostationary satellites

NASA Technical Reports Server (NTRS)

Sollfrey, W.

1984-01-01

The interference problems faced by nongeostationary satellites may be of major significance. A general discussion indicates the scope of the problems and describes several configurations of importance. Computer programs are described, which are employed by NASA/JPL and the U.S. Air Force Satellite Control Facility to provide interference-free scheduling of commands and data transmission. Satellite system mission planners are not concerned with the precise prediction of interference episodes, but rather with the expected total amount of interference, the mean and maximum duration of events, and the mean spacing between episodes. The procedures in the theory of probability developed by the author which permit calculation of such quantities are described and applied to several real cases. It may be anticipated that the problems will become steadily worse in the future as more and more data transmissions attempt to occupy the same frequency band.

Interference of conically scattered light in surface plasmon resonance.

PubMed

Webster, Aaron; Vollmer, Frank

2013-02-01

Surface plasmon polaritons on thin metal films are a well studied phenomena when excited using prism coupled geometries such as the Kretschmann attenuated total reflection configuration. Here we describe a novel interference pattern in the conically scattered light emanating from such a configuration when illuminated by a focused beam. We observe conditions indicating only self-interference of scattered surface plasmon polaritions without any contributions from specular reflection. The spatial evolution of this field is described in the context of Fourier optics and has applications in highly sensitive surface plasmon based biosensing.

Axial-Force Reduction by Interference Between Jet and Neighboring Afterbody

NASA Technical Reports Server (NTRS)

Pitts, William C.; Wiggins, Lyle E.

1960-01-01

Experimental results are presented for an exploratory investigation of the effectiveness of interference between jet and afterbody in reducing the axial force on an afterbody with a neighboring jet. In addition to the interference axial force., measurements are presented of the interference normal force and the center of pressure of the interference normal force. The free-stream Mach number was 2.94, the jet-exit Mach number was 2.71, and the Reynolds number was 0.25 x 10, based on body diameter. The variables investigated include static-pressure ratio of the jet (up to 9), nacelle position relative to afterbody, angle of attack (-5 deg to 10 deg), and afterbody shape. Two families of afterbody shapes were tested. One family consisted of tangent-ogive bodies of revolution with varying length and base areas. The other family was formed by taking a planar slice off a circular cylinder with varying angle between the plane and cylinder. The trends with these variables are shown for conditions near maximum jet-afterbody interference. The interference axial forces are large and favorable. For several configurations the total afterbody axial force is reduced to zero by the interference.

FAGE measurements of tropospheric HO with measurements and model of interferences

NASA Technical Reports Server (NTRS)

Hard, T. M.; Mehrabzadeh, A. A.; Chan, C. Y.; O'Brien, R. J.

1992-01-01

Ambient HO measurements by low-pressure laser-excited fluorescence with chemical modulation, and supporting ozone and water-vapor data, are presented for periods in May and August 1987. The observed peak daytime ambient HO concentrations are in the range (2.5 to 8) x 10 exp 6 molecules/cu cm and show small negative offsets due to photochemical interference. Direct measurements of the interference at fixed (O3) give the dependence on ambient (H2O) and on the modulating reagent (isobutane). At ambient (O3) = 30 ppb and 10 torr H2O, with excitation and detection at a total pressure of 4 torr, the net interference is equal to (HO) = -1.3 x 10 exp 6 molecules/cu cm. Production of HO by the reaction of isobutane with O(1D) accounts for the negative interference. Quenching of HO fluorescence by the modulating reagent contributes a smaller positive term to the interference; kinetic measurements of the quenching rate coefficient are reported. The experimental interference results are compared with a detailed kinetic model of HO production, excitation, relaxation, and detection; reasonable agreement is found.

Quinoa - Adaptive Computational Fluid Dynamics, 0.2

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

Bakosi, Jozsef; Gonzalez, Francisco; Rogers, Brandon

Quinoa is a set of computational tools that enables research and numerical analysis in fluid dynamics. At this time it remains a test-bed to experiment with various algorithms using fully asynchronous runtime systems. Currently, Quinoa consists of the following tools: (1) Walker, a numerical integrator for systems of stochastic differential equations in time. It is a mathematical tool to analyze and design the behavior of stochastic differential equations. It allows the estimation of arbitrary coupled statistics and probability density functions and is currently used for the design of statistical moment approximations for multiple mixing materials in variable-density turbulence. (2) Inciter,more » an overdecomposition-aware finite element field solver for partial differential equations using 3D unstructured grids. Inciter is used to research asynchronous mesh-based algorithms and to experiment with coupling asynchronous to bulk-synchronous parallel code. Two planned new features of Inciter, compared to the previous release (LA-CC-16-015), to be implemented in 2017, are (a) a simple Navier-Stokes solver for ideal single-material compressible gases, and (b) solution-adaptive mesh refinement (AMR), which enables dynamically concentrating compute resources to regions with interesting physics. Using the NS-AMR problem we plan to explore how to scale such high-load-imbalance simulations, representative of large production multiphysics codes, to very large problems on very large computers using an asynchronous runtime system. (3) RNGTest, a test harness to subject random number generators to stringent statistical tests enabling quantitative ranking with respect to their quality and computational cost. (4) UnitTest, a unit test harness, running hundreds of tests per second, capable of testing serial, synchronous, and asynchronous functions. (5) MeshConv, a mesh file converter that can be used to convert 3D tetrahedron meshes from and to either of the following formats: Gmsh, (http://www.geuz.org/gmsh), Netgen, (http://sourceforge.net/apps/mediawiki/netgen-mesher), ExodusII, (http://sourceforge.net/projects/exodusii), HyperMesh, (http://www.altairhyperworks.com/product/HyperMesh).« less

Drifting States and Synchronization Induced Chaos in Autonomous Networks of Excitable Neurons.

PubMed

Echeveste, Rodrigo; Gros, Claudius

2016-01-01

The study of balanced networks of excitatory and inhibitory neurons has led to several open questions. On the one hand it is yet unclear whether the asynchronous state observed in the brain is autonomously generated, or if it results from the interplay between external drivings and internal dynamics. It is also not known, which kind of network variabilities will lead to irregular spiking and which to synchronous firing states. Here we show how isolated networks of purely excitatory neurons generically show asynchronous firing whenever a minimal level of structural variability is present together with a refractory period. Our autonomous networks are composed of excitable units, in the form of leaky integrators spiking only in response to driving currents, remaining otherwise quiet. For a non-uniform network, composed exclusively of excitatory neurons, we find a rich repertoire of self-induced dynamical states. We show in particular that asynchronous drifting states may be stabilized in purely excitatory networks whenever a refractory period is present. Other states found are either fully synchronized or mixed, containing both drifting and synchronized components. The individual neurons considered are excitable and hence do not dispose of intrinsic natural firing frequencies. An effective network-wide distribution of natural frequencies is however generated autonomously through self-consistent feedback loops. The asynchronous drifting state is, additionally, amenable to an analytic solution. We find two types of asynchronous activity, with the individual neurons spiking regularly in the pure drifting state, albeit with a continuous distribution of firing frequencies. The activity of the drifting component, however, becomes irregular in the mixed state, due to the periodic driving of the synchronized component. We propose a new tool for the study of chaos in spiking neural networks, which consists of an analysis of the time series of pairs of consecutive interspike intervals. In this space, we show that a strange attractor with a fractal dimension of about 1.8 is formed in the mentioned mixed state.

Drifting States and Synchronization Induced Chaos in Autonomous Networks of Excitable Neurons

PubMed Central

Echeveste, Rodrigo; Gros, Claudius

2016-01-01

The study of balanced networks of excitatory and inhibitory neurons has led to several open questions. On the one hand it is yet unclear whether the asynchronous state observed in the brain is autonomously generated, or if it results from the interplay between external drivings and internal dynamics. It is also not known, which kind of network variabilities will lead to irregular spiking and which to synchronous firing states. Here we show how isolated networks of purely excitatory neurons generically show asynchronous firing whenever a minimal level of structural variability is present together with a refractory period. Our autonomous networks are composed of excitable units, in the form of leaky integrators spiking only in response to driving currents, remaining otherwise quiet. For a non-uniform network, composed exclusively of excitatory neurons, we find a rich repertoire of self-induced dynamical states. We show in particular that asynchronous drifting states may be stabilized in purely excitatory networks whenever a refractory period is present. Other states found are either fully synchronized or mixed, containing both drifting and synchronized components. The individual neurons considered are excitable and hence do not dispose of intrinsic natural firing frequencies. An effective network-wide distribution of natural frequencies is however generated autonomously through self-consistent feedback loops. The asynchronous drifting state is, additionally, amenable to an analytic solution. We find two types of asynchronous activity, with the individual neurons spiking regularly in the pure drifting state, albeit with a continuous distribution of firing frequencies. The activity of the drifting component, however, becomes irregular in the mixed state, due to the periodic driving of the synchronized component. We propose a new tool for the study of chaos in spiking neural networks, which consists of an analysis of the time series of pairs of consecutive interspike intervals. In this space, we show that a strange attractor with a fractal dimension of about 1.8 is formed in the mentioned mixed state. PMID:27708572

The Rubber Hand Illusion: Feeling of Ownership and Proprioceptive Drift Do Not Go Hand in Hand

PubMed Central

Rohde, Marieke; Di Luca, Massimiliano; Ernst, Marc O.

2011-01-01

In the Rubber Hand Illusion, the feeling of ownership of a rubber hand displaced from a participant's real occluded hand is evoked by synchronously stroking both hands with paintbrushes. A change of perceived finger location towards the rubber hand (proprioceptive drift) has been reported to correlate with this illusion. To measure the time course of proprioceptive drift during the Rubber Hand Illusion, we regularly interrupted stroking (performed by robot arms) to measure perceived finger location. Measurements were made by projecting a probe dot into the field of view (using a semi-transparent mirror) and asking participants if the dot is to the left or to the right of their invisible hand (Experiment 1) or to adjust the position of the dot to that of their invisible hand (Experiment 2). We varied both the measurement frequency (every 10 s, 40 s, 120 s) and the mode of stroking (synchronous, asynchronous, just vision). Surprisingly, with frequent measurements, proprioceptive drift occurs not only in the synchronous stroking condition but also in the two control conditions (asynchronous stroking, just vision). Proprioceptive drift in the synchronous stroking condition is never higher than in the just vision condition. Only continuous exposure to asynchronous stroking prevents proprioceptive drift and thus replicates the differences in drift reported in the literature. By contrast, complementary subjective ratings (questionnaire) show that the feeling of ownership requires synchronous stroking and is not present in the asynchronous stroking condition. Thus, subjective ratings and drift are dissociated. We conclude that different mechanisms of multisensory integration are responsible for proprioceptive drift and the feeling of ownership. Proprioceptive drift relies on visuoproprioceptive integration alone, a process that is inhibited by asynchronous stroking, the most common control condition in Rubber Hand Illusion experiments. This dissociation implies that conclusions about feelings of ownership cannot be drawn from measuring proprioceptive drift alone. PMID:21738756

Effects of Practice Schedule on Wind Instrument Performance: A Preliminary Application of a Motor Learning Principle

ERIC Educational Resources Information Center

Stambaugh, Laura A.; Demorest, Steven M.

2010-01-01

The effects of three practice schedules on beginning instrumental achievement were explored. A total of 19 seventh-grade clarinet and saxophone students completed one 18-minute practice session using either a blocked schedule causing a low level of cognitive (contextual) interference, a hybrid schedule causing a moderate level of interference, or…

Problems in the use of interference filters for spectrophotometric determination of total ozone

NASA Technical Reports Server (NTRS)

Basher, R. E.; Matthews, W. A.

1977-01-01

An analysis of the use of ultraviolet narrow-band interference filters for total ozone determination is given with reference to the New Zealand filter spectrophotometer under the headings of filter monochromaticity, temperature dependence, orientation dependence, aging, and specification tolerances and nonuniformity. Quantitative details of each problem are given, together with the means used to overcome them in the New Zealand instrument. The tuning of the instrument's filter center wavelengths to a common set of values by tilting the filters is also described, along with a simple calibration method used to adjust and set these center wavelengths.

Asynchronous Transfer Mode (ATM) Switch Technology and Vendor Survey

NASA Technical Reports Server (NTRS)

Berry, Noemi

1995-01-01

Asynchronous Transfer Mode (ATM) switch and software features are described and compared in order to make switch comparisons meaningful. An ATM switch's performance cannot be measured solely based on its claimed switching capacity; traffic management and congestion control are emerging as the determining factors in an ATM network's ultimate throughput. Non-switch ATM products and experiences with actual installations of ATM networks are described. A compilation of select vendor offerings as of October 1994 is provided in chart form.

Using process groups to implement failure detection in asynchronous environments

NASA Technical Reports Server (NTRS)

Ricciardi, Aleta M.; Birman, Kenneth P.

1991-01-01

Agreement on the membership of a group of processes in a distributed system is a basic problem that arises in a wide range of applications. Such groups occur when a set of processes cooperate to perform some task, share memory, monitor one another, subdivide a computation, and so forth. The group membership problems is discussed as it relates to failure detection in asynchronous, distributed systems. A rigorous, formal specification for group membership is presented under this interpretation. A solution is then presented for this problem.

DAI-CLIPS: Distributed, Asynchronous, Interacting CLIPS

NASA Technical Reports Server (NTRS)

Gagne, Denis; Garant, Alain

1994-01-01

DAI-CLIPS is a distributed computational environment within which each CLIPS is an active independent computational entity with the ability to communicate freely with other CLIPS. Furthermore, new CLIPS can be created, others can be deleted or modify their expertise, all dynamically in an asynchronous and independent fashion during execution. The participating CLIPS are distributed over a network of heterogeneous processors taking full advantage of the available processing power. We present the general framework encompassing DAI-CLIPS and discuss some of its advantages and potential applications.

Arbitrary-detuning asynchronous optical sampling pump-probe spectroscopy of bacterial reaction centers.

PubMed

Antonucci, Laura; Bonvalet, Adeline; Solinas, Xavier; Jones, Michael R; Vos, Marten H; Joffre, Manuel

2013-09-01

A recently reported variant of asynchronous optical sampling compatible with arbitrary unstabilized laser repetition rates is applied to pump-probe spectroscopy. This makes possible the use of a 5.1 MHz chirped pulse oscillator as the pump laser, thus extending the available time window to almost 200 ns with a time resolution as good as about 320 fs. The method is illustrated with the measurement in a single experiment of the complete charge transfer dynamics of the reaction center from Rhodobacter sphaeroides.

Gas-phase mercury reduction to measure total mercury in the flue gas of a coal-fired boiler.

PubMed

Meischen, Sandra J; Van Pelt, Vincent J; Zarate, Eugene A; Stephens, Edward A

2004-01-01

Gaseous elemental and total (elemental + oxidized) mercury (Hg) in the flue gas from a coal-fired boiler was measured by a modified ultraviolet (UV) spectrometer. Challenges to Hg measurement were the spectral interferences from other flue gas components and that UV measures only elemental Hg. To eliminate interference from flue gas components, a cartridge filled with gold-coated sand removed elemental Hg from a flue gas sample. The Hg-free flue gas was the reference gas, eliminating the spectral interferences. To measure total Hg by UV, oxidized Hg underwent a gas-phase, thermal-reduction in a quartz cell heated to 750 degrees C. Simultaneously, hydrogen was added to flash react with the oxygen present forming water vapor and preventing Hg re-oxidation as it exits the cell. Hg concentration results are in parts per billion by volume Hg at the flue gas oxygen concentration. The modified Hg analyzer and the Ontario Hydro method concurrently measured Hg at a field test site. Measurements were made at a 700-MW steam turbine plant with scrubber units and selective catalytic reduction. The flue gas sampled downstream of the selective catalytic reduction contained 2100 ppm SO2 and 75 ppm NOx. Total Hg measured by the Hg analyzer was within 20% of the Ontario Hydro results.

Synchronization properties of networks of electrically coupled neurons in the presence of noise and heterogeneities.

PubMed

Ostojic, Srdjan; Brunel, Nicolas; Hakim, Vincent

2009-06-01

We investigate how synchrony can be generated or induced in networks of electrically coupled integrate-and-fire neurons subject to noisy and heterogeneous inputs. Using analytical tools, we find that in a network under constant external inputs, synchrony can appear via a Hopf bifurcation from the asynchronous state to an oscillatory state. In a homogeneous net work, in the oscillatory state all neurons fire in synchrony, while in a heterogeneous network synchrony is looser, many neurons skipping cycles of the oscillation. If the transmission of action potentials via the electrical synapses is effectively excitatory, the Hopf bifurcation is supercritical, while effectively inhibitory transmission due to pronounced hyperpolarization leads to a subcritical bifurcation. In the latter case, the network exhibits bistability between an asynchronous state and an oscillatory state where all the neurons fire in synchrony. Finally we show that for time-varying external inputs, electrical coupling enhances the synchronization in an asynchronous network via a resonance at the firing-rate frequency.

Seismic behavior of a low-rise horizontal cylindrical tank

NASA Astrophysics Data System (ADS)

Fiore, Alessandra; Rago, Carlo; Vanzi, Ivo; Greco, Rita; Briseghella, Bruno

2018-05-01

Cylindrical storage tanks are widely used for various types of liquids, including hazardous contents, thus requiring suitable and careful design for seismic actions. The study herein presented deals with the dynamic analysis of a ground-based horizontal cylindrical tank containing butane and with its safety verification. The analyses are based on a detailed finite element (FE) model; a simplified one-degree-of-freedom idealization is also set up and used for verification of the FE results. Particular attention is paid to sloshing and asynchronous seismic input effects. Sloshing effects are investigated according to the current literature state of the art. An efficient methodology based on an "impulsive-convective" decomposition of the container-fluid motion is adopted for the calculation of the seismic force. The effects of asynchronous ground motion are studied by suitable pseudo-static analyses. Comparison between seismic action effects, obtained with and without consideration of sloshing and asynchronous seismic input, shows a rather important influence of these conditions on the final results.

Asynchronous threat awareness by observer trials using crowd simulation

NASA Astrophysics Data System (ADS)

Dunau, Patrick; Huber, Samuel; Stein, Karin U.; Wellig, Peter

2016-10-01

The last few years showed that a high risk of asynchronous threats is given in every day life. Especially in large crowds a high probability of asynchronous attacks is evident. High observational abilities to detect threats are desirable. Consequently highly trained security and observation personal is needed. This paper evaluates the effectiveness of a training methodology to enhance performance of observation personnel engaging in a specific target identification task. For this purpose a crowd simulation video is utilized. The study first provides a measurement of the base performance before the training sessions. Furthermore a training procedure will be performed. Base performance will then be compared to the after training performance in order to look for a training effect. A thorough evaluation of both the training sessions as well as the overall performance will be done in this paper. A specific hypotheses based metric is used. Results will be discussed in order to provide guidelines for the design of training for observational tasks.

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

NASA Astrophysics Data System (ADS)

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.

Experience with synchronous and asynchronous digital control systems

NASA Technical Reports Server (NTRS)

Regenie, V. A.; Chacon, C. V.; Lock, W. P.

1986-01-01

Flight control systems have undergone a revolution since the days of simple mechanical linkages; presently the most advanced systems are full-authority, full-time digital systems controlling unstable aircraft. With the use of advanced control systems, the aerodynamic design can incorporate features that allow greater performance and fuel savings, as can be seen on the new Airbus design and advanced tactical fighter concepts. These advanced aircraft will be and are relying on the flight control system to provide the stability and handling qualities required for safe flight and to allow the pilot to control the aircraft. Various design philosophies have been proposed and followed to investigate system architectures for these advanced flight control systems. One major area of discussion is whether a multichannel digital control system should be synchronous or asynchronous. This paper addressed the flight experience at the Dryden Flight Research Facility of NASA's Ames Research Center with both synchronous and asynchronous digital flight control systems. Four different flight control systems are evaluated against criteria such as software reliability, cost increases, and schedule delays.

Cascades on a stochastic pulse-coupled network

NASA Astrophysics Data System (ADS)

Wray, C. M.; Bishop, S. R.

2014-09-01

While much recent research has focused on understanding isolated cascades of networks, less attention has been given to dynamical processes on networks exhibiting repeated cascades of opposing influence. An example of this is the dynamic behaviour of financial markets where cascades of buying and selling can occur, even over short timescales. To model these phenomena, a stochastic pulse-coupled oscillator network with upper and lower thresholds is described and analysed. Numerical confirmation of asynchronous and synchronous regimes of the system is presented, along with analytical identification of the fixed point state vector of the asynchronous mean field system. A lower bound for the finite system mean field critical value of network coupling probability is found that separates the asynchronous and synchronous regimes. For the low-dimensional mean field system, a closed-form equation is found for cascade size, in terms of the network coupling probability. Finally, a description of how this model can be applied to interacting agents in a financial market is provided.

Modeling the Effects of Asynchronous Rotation on Secondary Eclipse Timings in HW VIr Binaries

NASA Astrophysics Data System (ADS)

Clancy, Padraig

2018-01-01

HW Vir binaries are post common envelope binaries consisting of a hot subdwarf and red dwarf, with light curves dominated by primary eclipses, a strong reflection effect, and secondary eclipses. They have orbital periods ranging from a few hours to half a day and are generally thought to be tidally locked; most studies assume both synchronous rotation and zero eccentricity when modeling HW Vir light curves and radial velocities. Their stable eclipse timings are frequently used in O-C studies to look for the presence of circumbinary objects, measure evolutionary changes in the orbital period, and even constrain the component masses through Roemer delay measurements of the secondary eclipse. While most systems are probably tidally locked or close to it, even slightly asynchronous rotation could theoretically shift the orbital phase of the reflection effect. Here we investigate how asynchronous rotation might affect measurements of secondary eclipse timings by generating thousands of synthetic light curves with a range of reflection effect phases, fitting eclipse timings, and creating O-C diagrams.

Cascades on a stochastic pulse-coupled network

PubMed Central

Wray, C. M.; Bishop, S. R.

2014-01-01

While much recent research has focused on understanding isolated cascades of networks, less attention has been given to dynamical processes on networks exhibiting repeated cascades of opposing influence. An example of this is the dynamic behaviour of financial markets where cascades of buying and selling can occur, even over short timescales. To model these phenomena, a stochastic pulse-coupled oscillator network with upper and lower thresholds is described and analysed. Numerical confirmation of asynchronous and synchronous regimes of the system is presented, along with analytical identification of the fixed point state vector of the asynchronous mean field system. A lower bound for the finite system mean field critical value of network coupling probability is found that separates the asynchronous and synchronous regimes. For the low-dimensional mean field system, a closed-form equation is found for cascade size, in terms of the network coupling probability. Finally, a description of how this model can be applied to interacting agents in a financial market is provided. PMID:25213626

Regression analysis of sparse asynchronous longitudinal data

PubMed Central

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

2015-01-01

Summary 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. PMID:26568699

Work-Life Interferences in the Early Stages of Academic Careers: The Case of Precarious Researchers in Italy

ERIC Educational Resources Information Center

Bozzon, Rossella; Murgia, Annalisa; Poggio, Barbara; Rapetti, Elisa

2017-01-01

This paper addresses the topic of work-life interferences in academic contexts. More specifically, it focuses on early career researchers in the Italian university system. The total availability required from those who work in the research sector is leading to significant transformations of the temporalities of work, especially among the new…

No Need for Templates in the Auditory Enhancement Effect

PubMed Central

Carcagno, Samuele; Semal, Catherine; Demany, Laurent

2013-01-01

The audibility of a target tone in a multitone background masker is enhanced by the presentation of a precursor sound consisting of the masker alone. There is evidence that precursor-induced neural adaptation plays a role in this perceptual enhancement. However, the precursor may also be strategically used by listeners as a spectral template of the following masker to better segregate it from the target. In the present study, we tested this hypothesis by measuring the audibility of a target tone in a multitone masker after the presentation of precursors which, in some conditions, were made dissimilar to the masker by gating their components asynchronously. The precursor and the following sound were presented either to the same ear or to opposite ears. In either case, we found no significant difference in the amount of enhancement produced by synchronous and asynchronous precursors. In a second experiment, listeners had to judge whether a synchronous multitone complex contained exactly the same tones as a preceding precursor complex or had one tone less. In this experiment, listeners performed significantly better with synchronous than with asynchronous precursors, showing that asynchronous precursors were poorer perceptual templates of the synchronous multitone complexes. Overall, our findings indicate that precursor-induced auditory enhancement cannot be fully explained by the strategic use of the precursor as a template of the following masker. Our results are consistent with an explanation of enhancement based on selective neural adaptation taking place at a central locus of the auditory system. PMID:23826348

No Need for Templates in the Auditory Enhancement Effect.

PubMed

Carcagno, Samuele; Semal, Catherine; Demany, Laurent

2013-01-01

The audibility of a target tone in a multitone background masker is enhanced by the presentation of a precursor sound consisting of the masker alone. There is evidence that precursor-induced neural adaptation plays a role in this perceptual enhancement. However, the precursor may also be strategically used by listeners as a spectral template of the following masker to better segregate it from the target. In the present study, we tested this hypothesis by measuring the audibility of a target tone in a multitone masker after the presentation of precursors which, in some conditions, were made dissimilar to the masker by gating their components asynchronously. The precursor and the following sound were presented either to the same ear or to opposite ears. In either case, we found no significant difference in the amount of enhancement produced by synchronous and asynchronous precursors. In a second experiment, listeners had to judge whether a synchronous multitone complex contained exactly the same tones as a preceding precursor complex or had one tone less. In this experiment, listeners performed significantly better with synchronous than with asynchronous precursors, showing that asynchronous precursors were poorer perceptual templates of the synchronous multitone complexes. Overall, our findings indicate that precursor-induced auditory enhancement cannot be fully explained by the strategic use of the precursor as a template of the following masker. Our results are consistent with an explanation of enhancement based on selective neural adaptation taking place at a central locus of the auditory system.

The analysis of the quality of the frequency control of induction motor carried out on the basis of the processes in the rotor circuit

NASA Astrophysics Data System (ADS)

Kodkin, V. L.; Anikin, A. S.; Baldenkov, A. A.

2018-01-01

The results of researches of asynchronous electric drives with the frequency control which are carried out for the purpose of establishment of causes and effect relationships between a control method, the implementable standard frequency converter of the Schneider Electric company (ATV-71, ATV-32) and its efficiency are given in article. Tests with asynchronous motors with wound rotor were for the first time carried out. It allowed registering during the experiments the instantaneous values not only the stator currents, but also rotor currents. Authors for the first time applied spectrum analysis of stator and rotor currents, it showed that «sensorless vector» control leads to origin of high-frequency harmonicas with the considerable amplitude and, as a result of they are non-sinusoidal of the created torque and inefficiency of the electric drive. The accelerations that are carried out during the researches to 94, 157 and 251 Rad/s confirmed this feature of vector control that appears incapable to linearize the asynchronous electric drive as it was supposed authors of a method. These results do not contradict theoretical provisions if not to neglect assumptions which usually become in case of an output of the equations of vector control. Unfortunately, the modern researchers do not subject these assumptions to doubts. Continued studies make it possible to create an effective frequency management of asynchronous electric drives required for current technology.

Visibility-Based Hypothesis Testing Using Higher-Order Optical Interference

NASA Astrophysics Data System (ADS)

Jachura, Michał; Jarzyna, Marcin; Lipka, Michał; Wasilewski, Wojciech; Banaszek, Konrad

2018-03-01

Many quantum information protocols rely on optical interference to compare data sets with efficiency or security unattainable by classical means. Standard implementations exploit first-order coherence between signals whose preparation requires a shared phase reference. Here, we analyze and experimentally demonstrate the binary discrimination of visibility hypotheses based on higher-order interference for optical signals with a random relative phase. This provides a robust protocol implementation primitive when a phase lock is unavailable or impractical. With the primitive cost quantified by the total detected optical energy, optimal operation is typically reached in the few-photon regime.

Importance of Pain Acceptance in Relation to Headache Disability and Pain Interference in Women With Migraine and Overweight/Obesity.

PubMed

Lillis, Jason; Graham Thomas, J; Seng, Elizabeth K; Lipton, Richard B; Pavlović, Jelena M; Rathier, Lucille; Roth, Julie; O'Leary, Kevin C; Bond, Dale S

2017-05-01

Pain acceptance involves willingness to experience pain and engaging in valued activities while pain is present. Though pain acceptance could limit both headache-related disability and pain interference in individuals with migraine, few studies have addressed this issue. This study evaluated whether higher levels of total pain acceptance and its two subcomponents, pain willingness and activity engagement, were associated with lower levels of headache-related impairment in women who had both migraine and overweight/obesity. In this cross-sectional study, participants seeking weight loss and headache relief in the Women's Health and Migraine trial completed baseline measures of pain acceptance (Chronic Pain Acceptance Questionnaire [CPAQ]), headache-related disability (Headache Impact Test-6), and pain interference (Brief Pain Inventory). Migraine headache frequency and pain intensity were assessed daily via smartphone diary. Using CPAQ total and subcomponent (pain willingness and activity engagement) scores, headache frequency, pain intensity, and body mass index (BMI) as predictors in linear regression, headache-related disability, and pain interference were modeled as outcomes. On average, participants (n = 126; age = 38.5 ± 8.2 years; BMI = 35.3 ± 6.6 kg/m 2 ) reported 8.4 ± 4.7 migraine days/month and pain intensity of 6.0 ± 1.5 on a 0-10 scale on headache days. After correcting for multiple comparisons (adjusted α = .008), pain willingness was independently associated with both lower headache-related disability (P < .001; β = -0.233) and pain interference (P < .001; β = -0.261). Activity engagement was not associated with headache-related disability (P = .128; β = -0.138) and pain interference (P = .042; β = -0.154). CPAQ total score was not associated with headache-related disability (P = .439; β = 0.066) and pain interference (P = .305; β = 0.074). Pain intensity was significantly associated with outcomes in all analyses (Ps < .001; βs 0.343-0.615). Higher pain willingness, independent of degree of both migraine severity and overweight, is associated with lower headache-related disability and general pain interference in treatment-seeking women with migraine and overweight/obesity. Future studies are needed to clarify direction of causality and test whether strategies designed to help women increase pain willingness, or relinquish ineffective efforts to control pain, can improve functional outcomes in women who have migraine and overweight/obesity. © 2017 American Headache Society.

Work-Home Interference, Perceived Total Workload, and the Risk of Future Sickness Absence Due to Stress-Related Mental Diagnoses Among Women and Men: a Prospective Twin Study.

PubMed

Svedberg, Pia; Mather, Lisa; Bergström, Gunnar; Lindfors, Petra; Blom, Victoria

2018-02-01

Work-home interference has been proposed as an important explanation for sickness absence (SA). Previous studies show mixed results, have not accounted for familial factors (genetics and shared everyday environment), or investigated diagnosis specific SA. The aim was to study whether work-home interference and perceived total workload predict SA due to stress-related mental diagnoses, or SA due to other mental diagnoses, among women and men, when adjusting for various confounders and familial factors. This study included 11,916 twins, 19-47 years (49% women). Data on work-to-home and home-to-work conflicts, perceived total workload, and relevant confounders were derived from a 2005 survey, and national register data on SA spells until 2013 were obtained. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated. Discordant twin pair design was applied to adjust for familial factors. Each one unit increase in work-to-home and home-to-work conflicts, and perceived total workload was associated with higher odds for SA due to stress-related mental diagnoses and to SA due to other mental diagnoses among women, when adjusting for sociodemographic factors (ORs 1.15-1.31). Including health or familial factors, no associations remained. For men, each one unit increase in work-to-home conflicts was associated with higher odds for SA due to stress-related diagnoses (ORs 1.23-1.35), independently of confounders. Work-to-home conflict was independently associated with future SA due to stress-related diagnoses among men only. Health- and work-related factors seem to be important confounders when researching work-home interference, perceived total workload, and SA. Not including such confounders involves risking drawing incorrect conclusions. Further studies are needed to confirm sex differences and whether genetic factors are important for the associations studied.

A generalized population dynamics model for reproductive interference with absolute density dependence.

PubMed

Kyogoku, Daisuke; Sota, Teiji

2017-05-17

Interspecific mating interactions, or reproductive interference, can affect population dynamics, species distribution and abundance. Previous population dynamics models have assumed that the impact of frequency-dependent reproductive interference depends on the relative abundances of species. However, this assumption could be an oversimplification inappropriate for making quantitative predictions. Therefore, a more general model to forecast population dynamics in the presence of reproductive interference is required. Here we developed a population dynamics model to describe the absolute density dependence of reproductive interference, which appears likely when encounter rate between individuals is important. Our model (i) can produce diverse shapes of isoclines depending on parameter values and (ii) predicts weaker reproductive interference when absolute density is low. These novel characteristics can create conditions where coexistence is stable and independent from the initial conditions. We assessed the utility of our model in an empirical study using an experimental pair of seed beetle species, Callosobruchus maculatus and Callosobruchus chinensis. Reproductive interference became stronger with increasing total beetle density even when the frequencies of the two species were kept constant. Our model described the effects of absolute density and showed a better fit to the empirical data than the existing model overall.

Measurement of dew droplets in initial deposition at dew point by using a phase-shift interference microscope

NASA Astrophysics Data System (ADS)

Matsumoto, Shigeaki; Toyooka, Satoru; Hoshino, Mitsuo

2002-09-01

In order to measure the total mass per unit area of dew droplets deposited on a metal plate in the dew-point hygrometer, the shape of a dew droplet deposited on a copper plate was measured accurately by using an interference microscope that employed a phase-shift technique. The microscope was constructed by adding a piezoelectric transducer to an usual interference microscope. A simple method that uses a conventional speaker horn and an optical fiber cable was introduced to depress speckle noise. The shape of a dew droplet deposited on the copper plate surface with 0.1 μm in average roughness was measured with an accuracy of +/-3nm. The mass of a dew droplet could be calculated numerically from the volume of its shape and was of the order of 10-9 g. The total mass of dew droplets deposited per unit area and the deposition velocity were obtained under a gentle wind. The total mass was the order of 10-5 g/cm2 at the beginning of deposition and the deposition velocity was ranged from 2x10-6 to 6x10-5 g/cm2.min.

Analysis of backward error recovery for concurrent processes with recovery blocks

NASA Technical Reports Server (NTRS)

Shin, K. G.; Lee, Y. H.

1982-01-01

Three different methods of implementing recovery blocks (RB's). These are the asynchronous, synchronous, and the pseudo recovery point implementations. Pseudo recovery points so that unbounded rollback may be avoided while maintaining process autonomy are proposed. Probabilistic models for analyzing these three methods under standard assumptions in computer performance analysis, i.e., exponential distributions for related random variables were developed. The interval between two successive recovery lines for asynchronous RB's mean loss in computation power for the synchronized method, and additional overhead and rollback distance in case PRP's are used were estimated.

High Performance Asynchronous Limited Sensing Algorithms for CSMA and CSMA-CD Channels.

DTIC Science & Technology

1985-03-01

for CSM and CSMA-CD Channels" M. Geargiopoulos L. Merakos P. Papantoni-Kazakos- Technical Report UCT/ DEECS /TR-85-2 Mrh1985 iDISTRIBUTION STAEmEN 2j C...Perforance Asynchronous Limited Sensing Algoit~5 forCSMAandCSMA-CD Channels" M1. Georgiop0 ul 0 5 L. Merakos P. PaPantoni-.Kazakos Technical Report UCT/ DEECS ...SCHEDULE unlimited. 4 PERFORMING ORGANiZATION REPORT NUMBERIS) 5. MONITORING ORGANIZATION REPORT NUMBERIS" UCT/ DEECS /TR-85-2 SR-TR. 85-0 398 6& NAME OF

Bayesian operational modal analysis with asynchronous data, Part II: Posterior uncertainty

NASA Astrophysics Data System (ADS)

Zhu, Yi-Chen; Au, Siu-Kui

2018-01-01

A Bayesian modal identification method has been proposed in the companion paper that allows the most probable values of modal parameters to be determined using asynchronous ambient vibration data. This paper investigates the identification uncertainty of modal parameters in terms of their posterior covariance matrix. Computational issues are addressed. Analytical expressions are derived to allow the posterior covariance matrix to be evaluated accurately and efficiently. Synthetic, laboratory and field data examples are presented to verify the consistency, investigate potential modelling error and demonstrate practical applications.

Interference effects of categorization on decision making.

PubMed

Wang, Zheng; Busemeyer, Jerome R

2016-05-01

Many decision making tasks in life involve a categorization process, but the effects of categorization on subsequent decision making has rarely been studied. This issue was explored in three experiments (N=721), in which participants were shown a face stimulus on each trial and performed variations of categorization-decision tasks. On C-D trials, they categorized the stimulus and then made an action decision; on X-D trials, they were told the category and then made an action decision; on D-alone trials, they only made an action decision. An interference effect emerged in some of the conditions, such that the probability of an action on the D-alone trials (i.e., when there was no explicit categorization before the decision) differed from the total probability of the same action on the C-D or X-D trials (i.e., when there was explicit categorization before the decision). Interference effects are important because they indicate a violation of the classical law of total probability, which is assumed by many cognitive models. Across all three experiments, a complex pattern of interference effects systematically occurred for different types of stimuli and for different types of categorization-decision tasks. These interference effects present a challenge for traditional cognitive models, such as Markov and signal detection models, but a quantum cognition model, called the belief-action entanglement (BAE) model, predicted that these results could occur. The BAE model employs the quantum principles of superposition and entanglement to explain the psychological mechanisms underlying the puzzling interference effects. The model can be applied to many important and practical categorization-decision situations in life. Copyright © 2016 Elsevier B.V. All rights reserved.