Interruption Conditions Research Articles

Medication administration errors made among undergraduate nursing students: A need for change in teaching methods.

Systems factors, such as interruptions, contribute to nursing errors. Gaining an understanding of what contributes to nursing student errors can inform educational strategies aimed to improve patient safety. The aims of this study were to investigate: (a) within-subjects differences in error rates among nursing students during interrupted compared to uninterrupted simulated medication administration, (b) types of medication administration errors made by nursing students, and (c) nursing students' perceptions of their ability to independently administer medication. A descriptive comparative within-subjects design was utilized in this two-site study. Data on errors were collected via direct observation. Senior baccalaureate nursing student participants discussed their experience of interrupted and uninterrupted simulated medication administration during individual debriefing sessions. Nearly one-third of participants made errors. Error rates were similar in interrupted (19.4%) and uninterrupted (16.7%) conditions. Near-misses, which were not included in the error rates, were reported by 8% of participants. The most common error types were documentation and dose errors. Students attributed the interruption and lack of independent medication administration practice as causes for errors. Educational programs must adequately prepare nursing students for independent safe medication administration in complex work environments. The inclusion of systems factors in educational modalities is critical.

The Effects of Fragmented and Continuous Interruptions on Online Task Performance

This study examines the effect of online interruptions on task performance. Two hundred and eighty players played a game designed to simulate an online environment decision-making process. The manipulation was achieved through an intervention design. Participants were exposed to messages in six interruption conditions as they played: (i) slow-fragmented text, (ii) fast-fragmented text, (iii) slow-fragmented image, (iv) fast-fragmented image, (v) continuous text, and (vi) continuous image. We compared text-only interruptions and image interruptions within different rates of interruption. The results indicate that participants with continuous text interruptions display the same performance as those without interruptions; participants who experience fast text interruptions perform the best; participants exposed to slow text interruptions performed poorly on tasks. These results imply the conditions in which controlling the rate and richness of online interruptions could improve task performance.

Investigation of intermittent cutting mechanism of abrasive particles in ultrasonic-assisted external cylindrical honing

Ultrasonic-assisted honing, which is a finishing grinding method, has been considered effective for improving the cutting performance of abrasive particles. However, the effect mechanism of the ultrasonic vibration on the cutting process of abrasive particles has not yet been clarified, which hinders the application and development of this technology. In this study, new kinematics and cutting process models of a single abrasive particle in ultrasonic-assisted external cylindrical honing (UAECH) were established. The parameters and interruption conditions affecting the intermittent cutting process of the abrasive particle were clarified based on the coupling effect of ultrasonic vibration and rotation of workpiece. Finite element simulation analysis has revealed that the increases in ultrasonic frequency and amplitude can reduce the interruption threshold and cutting time proportion in the intermittent cutting process of abrasive particles mainly by increasing the relative velocity of abrasive particles. Furthermore, for the cutting depth and rotation speed, their influence on the intermittent cutting process is mainly based on the change of the deformation rate of workpiece material. Moreover, it was found that there was counteraction effect between the tangential forces on the symmetrical surfaces of the abrasive particle in UAECH, which can help reduce the tangential honing force and improve the honing performance. The experimental results demonstrated a significant improvement in the average tangential honing force in UAECH and novel dents surface topography, which can provide guidance for the application of ultrasonic vibration in the grinding field and development of forming processes for functional surface topography in honing.

Data Analysis and Decision on Navigation Safety of Yangshan Port Channel

Aiming at the problem of pilotage disruption under high wind control, this paper provides statistics on wind direction and wind levels during high wind control days, measures pilotage disruption at Yangshan Port for a total of ten years (from 2011 to 2020), notes the wind direction and wind levels that trigger pilotage disruption, and models and analyzes the effects of different wind directions and wind-level coupling on pilotage disruption. In addition, the difference of traffic flow in the alert area under normal and interrupted conditions of pilotage is analyzed by combining pilotage interruption data and the observation data of the alert area. The law of traffic volume and speed of container ships of different lengths is also analyzed. Based on the data of each observation line, the speed and time of ships in the warning area were evaluated by combining the speed, heading, and time from the records. The traffic law of different types of ships are summarized; that is, the ship’s speed in the caution area is roughly positively correlated with its length: the longer the ship’s length, the faster the ship’s speed, and the less the sailing time. The article provides a basis for the research of pilotage safety operations.

Economic impact of crude oil supply disruption on social welfare losses and strategic petroleum reserves

Strategic petroleum reserves are a major too to mitigate the risk oil supply disruptions and to discourage the use of energy as a geopolitical weapon. Moreover, oil supply disruption severely damages the energy security and economic growth as well. Therefore, we used econometric estimation and combine numerous relevant, multidimensional and comprehensive set of indicators through Principal Component Analysis (PCA) to measure the physical oil supply risk and strategic petroleum reserves in order to enhance the social welfare in South Asia. Our analysis proved that 30% of the shortfall in crude oil distribution in markets accounts for the biggest vacillated system of crude oil costing. This shortfall immediately increases forecasted social welfare wastage via a 40% decrease in gross domestic product, which is estimated at $700 in South Asia and $3000 in the largest crude oil economy. The quantity and value of oil supply required for the strategic petroleum reserves to trigger the optimum building and drawdown of the oil are calculated using PCA and game solution. Limited testing of private sector inventory adjustments was less encouraging, suggesting that private actions may have partially offset some government reductions. Therefore, anticipated costs grow at 4% in regular market situations, decrease nearly 8% in interrupted market conditions, and decrease 9% in highly interrupted market conditions. With the benefit of retrospection, improved management may have considerably increased the value of the strategic petroleum reserves, particularly during the peak disruption. A quantitative risk evaluation of crude oil disruptions reveals the importance of crude oil accumulation and the drawdown of vital national crude oil stockpiles as governments seek to optimize consumer well-being while simultaneously maintaining control over oil stockpiles.

Covert non-orthogonal multiple access communication assisted by multi-antenna jamming

As the Internet of Things (IoT) becomes increasingly popular, the amount of information transmitted through the IoT network has increased significantly. Therefore, the privacy and security problem of the transmitted information has become a major area of focus. Motivated by this, this paper considers the covert communication based on non-orthogonal multiple access (NOMA), which consists of a transmitter, a legal user, a warden with power detection function and a multi-antenna jammer. To realize the covert communication between the transmitter and the legitimate user, the detection error probability of the warden is firstly derived, and then the optimal detection threshold and the minimum detection error probability (MDEP) are obtained. In addition, with the aim of designing this system, the average MDEP of the warden is calculated, and the closed form solution for the outage probability (OP) of the communication link is obtained. Then, a scheme is proposed to optimize the covertness of this system under the covertness constraint and interruption constraint, through which the maximum covert throughput of the system can be obtained. The simulated numerical results validate the theoretical analysis, and testify that: (i) the detection performance of the warden can be reduced by increasing the maximum jamming power of the jammer or reducing the transmitting power of the transmitter; (ii) by optimizing the power allocation factor, the maximum covert throughput of the system can be obtained under the premise of satisfying the covertness constraint and interruption condition; (iii) the proposed optimization scheme can enhance the covertness performance of this system.

The psychology of getting busy: Multitasking as a consequence of goal activation.

With the constantly increasing popularity of human multitasking, it is crucial to know why people engage in simultaneous task performance or switch between unfinished tasks. In the present article, we propose that multitasking behavior occurs when people have multiple active goals; the greater their number, the greater the degree of multitasking. The number of currently considered goals is reduced where one goal's significance overrides the others, reducing the degree of multitasking. We tested these hypotheses in a series of six studies in which we manipulated either goal activation or goal importance and investigated how this affected the degree of multitasking. The results showed that the more active goals participants actively entertained, the more likely they were to plan to engage in multitasking (Studies 1 and 5), and the more often they switched between tasks (Study 2). They also multitasked more under high interruption condition assumed to activate more goals than low interruption condition (Study 3). Further, we demonstrated that the degree of multitasking was significantly decreased by reducing the number of simultaneously considered goals, either via increasing the relative importance of one of the goals (Study 4) or via inducing greater commitment to one of the goals through a mental contrasting procedure (Study 5). Study 6, carried out in an academic context, additionally showed that the importance of a class-related goal negatively predicted media multitasking in class. The results thus show that goal activation is the underlying mechanism that explains why people multitask. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

How to refocus attention on working memory representations following interruptions—Evidence from frontal theta and posterior alpha oscillations

Interruptions lead to a deterioration of primary task performance. Applied research usually describes a delay in primary task resumption as an essential component of this performance deficit. Here, we investigate this approach using electrophysiological correlates of the focusing of attention within working memory, a process that is fundamental to switching between different tasks. A lateralized working memory task was frequently interrupted by either a high- or low-demanding arithmetic task and a subsequent retrospective cue indicated the working memory item required for later report. The detrimental effect of interruptions on primary task performance was most pronounced for high-demanding interruptions. After retro-cue presentation, fronto-central theta power (4-7Hz) was lowest following high-demanding interruptions and posterior alpha power (8-14 Hz) was less suppressed in the two interruption conditions. These effects might be related to a deficit in attentional control processes following the retrospective cue. Furthermore, we introduce the suppression of posterior alpha power contralateral to the remembered primary task stimuli during the interruption phase as a temporal marker for primary task resumption. Especially for cognitively demanding interruption tasks, this effect seems to overlap in time with the processing of the interruption, which should contribute to the primary task performance deficit.

Designing and Evaluating a Scale-Driven Wearable Diagnostic Assessment System for Children with Neurodevelopmental Disorders

In two experiments, we played an audio recording of a conversational exchange for N = 224 and N = 144 participants, manipulating the point of interruption (early, late or no interruption = control) and types of interruption (change of subject, disagreement, clarification and agreement) in order to understand their effects on naïve observers' perception (Study 1) and evaluation of interruptions (Study 2). Results show that: early rather than late interruptions, changing the subject rather than disagreement, disagreement rather than clarification, and clarification rather than agreement were regarded more as interruptions and were evaluated more negatively; although both criteria—type and point of interruption—showed significant effects, naïve observers used the point of interruption more than the type of interruption for identifying and evaluating the interruptions. Valence and perception of a conversational transition were correlated: in the interruption condition and even in non-interruption conditions, the more a turn taking was evaluated as negative, the more it was perceived to be an interruption. Finally, the results did not support the gender hypothesis. Results were interpreted in terms of politeness theory and considering cultural and contextual factors.

Fitting Volume Delay Functions under interrupted and uninterrupted flow conditions at Greek urban roads

This paper presents the calibration of the most commonly used Volume Delay Functions (VDF): BPR, Conical, Akcelik and Modified Davidson, for an urban area populated by over 1 million inhabitants, the city of Thessaloniki in Greece. The estimation of the unknown coefficients was carried out for a typical freeway, the ring road of the city, and selected arterial and collected roads of the city center, through recent data of hourly observed vehicle speeds and volumes obtained from video recordings and loop detectors. The BPR function yielded the highest accuracy across all the examined road sections and was characterized as the most suitable to simulate and interpret the existing traffic conditions. The estimated coefficients differed significantly from the values proposed in the pertinent literature, which highlights the importance of using locally derived data for the calibration of the VDFs.

Edge and fog computing using IoT for direct load optimization and control with flexibility services for citizen energy communities

The grid congestion and imbalance problems are nowadays approached through a new perspective of the energy flexibility services that are usually acquired through a bidding process by aggregators on behalf of grid operators and electricity retailers and traded via Local Flexibility Markets (LFM). They can be also acquired at a fixed price under specific conditions of interruption and operation. The flexibility services are offered by electricity consumers and prosumers that own generation and storage facilities and controllable appliances, adding value to the emerging Information and Communications Technology (ICT) and smart metering technologies. In this paper, we propose an adaptive direct load optimization and control with an Internet of Things (IoT) architecture and compare it with a classic approach of Direct Load Control (DLC). The optimization process consists in a day-ahead scheduling that aims to minimize the electricity expense using programmable appliances (shift) and their operational constraints, whereas the adaptive DLC comes on top of it with additional load control (shed) using flexibility to cope with real-time uncertainties including the temperature comfort of the consumers. As the consumption is recorded using smart meters and appliances that continuously generate large volumes of data at different time resolution and formats requiring fast analytical and decisional processes, the challenge consists in correlating and integrating the optimization requirements with IoT and appliance control within an edge and fog computing architecture to overcome grid congestion, power capacity scarcity and forecast errors. The simulations are performed using real open datasets consisting in 114 single-family houses that form a small community with modern and flexible appliances, providing that the electricity bill reduction is up to 22.62%. Furthermore, to validate, several indicators for consumers and aggregator are proposed: total daily used flexibility decreased on average by 21.05%, number of interruptions also decreased on average by 20.51%, maximum number of interruptions per appliance decreased by 58.33%, while Peak to Average Ratio (PAR) improved by 32% when implementing the proposed DLC architecture.

Resuming a Dynamic Task Following Increasingly Long Interruptions: The Role of Working Memory and Reconstruction.

Studies examining individual differences in interruption recovery have shown that higher working memory capacity (WMC) attenuated the negative impact of interruption length on resumption, at least in static contexts. In continuously evolving (or dynamic) situations, however, working memory may not be as central to the effective resumption of a task, especially in the case of long interruptions. One of the main theories of task interruption suggests that dynamic task resumption could depend on a reconstruction of the primary task context, that is, a visual examination of the post-interruption environment. To better define the role of working memory and reconstruction processes in interruption recovery, the current study examined the association between (1) dynamic task resumption following interruptions of various lengths and (2) two cognitive abilities chosen to operationalize the processes under study, namely, WMC and visual search capacity. Participants performed a multiple object tracking task which could be uninterrupted or interrupted for 5, 15, or 30 s while the hidden stimuli continued their trajectory. They also completed tasks measuring the two cognitive abilities of interest. The results revealed that WMC contributed to post-interruption accuracy regardless of interruption duration. On the contrary, visual search capacity was related to faster resumption in the 15-s and 30-s interruption conditions only. Those results show that working memory plays a preponderant role in resumption not only in static, but also in dynamic contexts. However, our study suggests that this mechanism must share the limelight with reconstruction following lengthy interruptions in dynamic settings.

Effects of brief periods of clear vision on the defocus-mediated changes in axial length and choroidal thickness of human eyes.

To investigate the influence of brief, repeated periods of clear vision on the changes in axial length and choroidal thickness in response to short-term imposed defocus. The right eye of 16 young adults was exposed to 60min episodes of continuous and interrupted defocus conditions (+3DS and -3DS) over five separate sessions, with the left eye optimally corrected for distance. For interrupted defocus, 2min episodes of clear vision were imposed before each 15min episode of myopic or hyperopic defocus (2/15min). For hyperopic defocus, the effect of frequency of clear vision exposure was also assessed by imposing 1min of clear vision before each 7.5min of defocus (1/7.5min). The right eye axial length and choroidal thickness were measured before, during and after each defocus condition. After 60min of continuous hyperopic defocus the eye elongated significantly by +9±9μm (p=0.02). When exposed to interrupted (2/15min) hyperopic defocus, axial elongation was significantly reduced by 77% compared to continuous hyperopic defocus (p=0.03), with a final change of only +2±10μm relative to baseline. During interrupted (1/7.5min) hyperopic defocus, axial elongation reduced slightly compared to continuous hyperopic defocus (+6±8μm relative to baseline, p=0.12). For continuous myopic defocus, a reduction in axial length occurred but was not statistically significant (p>0.05). A similar pattern of response was observed for choroidal thickness changes with continuous and interrupted (1/7.5min) hyperopic defocus conditions. Brief periods of clear vision can diminish axial elongation and choroidal thinning induced by hyperopic defocus exposure in human eyes. If hyperopic defocus contributes to myopia progression in humans, then interruption with brief periods of clear vision could reduce its myopiagenic effects.

Transient Process at Atmospheric Discharge into the Landline and the Appearance of an Electric Arc in the Switch

This document proposes a model of the process of atmospheric discharge of overhead lines followed by an electric arc. The intensity of atmospheric discharges, followed by electric arc and destruction, is determined by the difference in potential and current. Such a structure and form of discharge make it difficult to analyze the transient process and obtain adequate solutions. That is why the model of the transient process in the electric arc of the switch under the conditions of interruption of the AC circuit is specially analyzed. Simple equivalent schemes for the analysis of phenomena with given values of linear parameters are presented, which are very simple to apply. All influential parameters by which the overvoltage values in the model can be estimated were also taken into account. The evaluation of the proposed model was performed using the adapted MATLAB program psbsurlightcuurent for atmospheric electrical discharge, which contains a high frequency current source. The verified simulation method was used to verify the results as part of a method derived from artificial intelligence algorithms. The process simulation program, the obtained voltage and current diagrams confirm the application of the simulation algorithm model.

Detection of Stator Winding Short Circuit Faults Through Magnetic Fields In Induction Motors

In applications in the industrial world, the use of induction motors has been widely used in operation because induction motors have many advantages, although they have many advantages, induction motors themselves also have disadvantages, namely having high starting currents. In many cases the damage to the induction motor, the damage to the stator due to a short circuit, is a frequent failure, this damage can cause considerable losses because the motor can stop operation So this research will discuss about the detection of short circuit faults in the stator winding through leaky flux using a flux sensor that is placed outside the motor and placed radially and using the Fast Fourier Transform (FFT) method. Damage to the short circuit is done by reconstructing the stator winding of the induction motor. There are two variations of short circuit damage, namely short circuit winding 1 to winding 3 and short circuit winding 2 to winding 10 on an induction motor. The short circuit data is then processed using the Fast Fourier Transform method which produces data in the form of voltage to frequency. The results of the percentage of success of short circuit fault detection seen from the loaders have an average percentage of 50%, at no load conditions can detect short circuit faults by 100%. In conditions of short circuit interruption 1-3 has a success percentage of 30% and short circuit fault 2-10 by 70%. The existence of this system is expected to be able to anticipate any damage that can cause considerable and fatal losses.

Mitigation of power quality issues in smart grid using levy flight based moth flame optimization algorithm

Now a days, energy demand have been increasing due to industrialization factors in the world. The energy demand and environmental problems also increased such as global warming and air pollution. The problems must be solved by introducing renewable energy resources in grid connection. The increasing demand solved by combining renewable energy resources with grid connection which is the smart grid (SG) system. The SG system is affected by the voltage collapses and power quality (PQ) issues such as voltage sag, voltage swell, voltage interruption etc. Because of connection of renewable resources with grid connection. In the SG is consists of renewable energy systems (RES) and power storage devices. The RES are photovoltaic (PV), wind turbine (WT) that are connected with grid through the voltage source inverter (VSI). In the SG system, the power flow, power management and PQ are the main problems which must be solved to maintain stable operation. Thus, in this paper, Levy flight-moth flame optimization (LFMFO) is developed for improving the performance and mitigates the PQ issues in the SG system. To avoid the local optima and improve the global search of MFO, Levy flight is utlized in the SG system. Using the proposed algorithm, improve the performance of the SG with the voltage, droop control based low voltage ride through (LVRT) and damping controls for reduce the PQ issues. The proposed strategy is validated in the MATLAB/Simulink platform and investigated the PV power, wind power, voltage sag, current, voltage swell and voltage interruption. The proposed method shows the ability to mitigate PQ issues in SG system. The proposed methods provide the best optimal results toward to achieve objective of MG system. Under voltage sag, voltage swell and voltage interruption conditions of SG, proposed methods shows best performance to improve stability of the system. The execution of proposed system is shown and compared with the existing techniques of Cuckoo search (CS) algorithm and particle swarm optimization (PSO) algorithm.

Grain yield and associated physiological traits of rapeseed (<em>Brassica napus L.</em>) cultivars under different planting dates and drought stress at the flowering stage

The adverse effects of abiotic stresses have always restricted oilseed crop production, particularly in arid and semi-arid regions. On the other side, global climate change has led us to adapt planting dates and select tolerant cultivars to encounter the new climatic conditions. To evaluate the effect of late-season drought stress under different planting dates on rapeseed cultivars, an experiment was conducted as a factorial split-plot based on randomised complete block design in Karaj region-Iran, during 2015-2017. Planting date and irrigation treatments were considered in the main plots as factorial and cultivars were placed in subplots. Two planting dates were regular date (October 7) (PD1) and late planting date (November 6). Irrigation was also carried out at two levels of normal irrigation (NI) and irrigation interruption from flowering stage onwards. Experimental cultivars included ES Hydromel, ES Alonso, ES Darko, ES Lauren, and Ahmadi. According to the results, late-season drought stress and delayed planting date reduced leaf relative water content (LRWC), total chlorophyll content, proline, and grain yield, and increased stomatal resistance (SR), canopy temperature, and leaf soluble carbohydrates (CLS) in rapeseed cultivars. The highest grain yield (4505.6 kg ha–1) was obtained in NI conditions and PD1. Significant interactions of planting date, irrigation, and cultivar on LRWC, SR, and CLS traits indicated that the ES Hydromel was the most tolerant hybrid cultivar with the highest LRWC and the lowest SR and CLS levels compared to other ones in unfavourable conditions of late-season drought stress and delayed planting. To confirm these results, cluster analysis led to the formation of two clusters, where ES Darko, Ahmadi, and ES Lauren cultivars were placed in the sensitive cluster and ES Hydromel and ES Alonso cultivars were assigned to the tolerant cluster. Therefore, ES Hydromel can be introduced as a superior cultivar to be selected as a genotype that presents acceptable resistance under drought stress and late sowing in arid and semi-arid regions. Highlights- ES Hydromel as a new hybrid cultivar under late-season drought stress conditions is proposed in cold temperate regions with arid and semi-arid climates. - Late sowing date has extremely caused a negative effect on the winter rapeseed’s physiological traits during the cold season. - The result of cluster analysis based on grain yield loss led to the formation of two clusters, which ES Hydromel and ES Alonso with lower yield loss were grouped in the tolerant cluster. - ES Hydromel in the late planting date and irrigation interruption conditions obtained the lowest stomatal resistance. - ES Hydromel on regular date and normal irrigation conditions obtained the highest leaf relative water content.

Simulation of Magnetic Electron Cut-off in a Vacuum Switch with an Anode in the Form of an Inductor

The simulation of the process of magnetic cut-off of electrons in a vacuum switch (VC) with an anode in the form of an inductor was performed. Calculations were performed according to the physico-topological model of physical processes in the vacuum switch, which took into account current distribution along electrodes, the trajectory of electrons emitted by the cathode and the conditions of current interruption in VC. Determination of current distribution along the anode, as well as configurations of electric and magnetic fields were performed according to a mathematical model based on Maxwell's equations for vacuum and conductive medium of the anode and boundary conditions adapted to the shape of the elements of the VC. Material equations were also used for certainty. The initial kinetic energy of electrons emitted from the cathode was set equal to zero. Their direction of departure from the cathode surface was determined by the direction of the lines of force of the electric field near the surface. Electron emission was given by the uniform distribution of emission points on the surface of the cathode tip. The calculation of the structure of the magnetic field was performed taking into account the secondary magnetic fields and the current distribution over the cross section of the anode inductor, which is caused by the skin effect.It is established that a decrease in the step of the inductor turns and an increase in the amplitude of the current pulse in it lead to an increase in the magnetic field strength in the cathode region, which improves the focusing of electrons. At anode-cathode voltage of 10 kV, the step of the inductor of 6 mm and the amplitude of the anode inductor current pulse of 900 A, all the electrons emitted from the cathode are focused outside the anode.The influence of design parameters on the electron cut-off efficiency is determined. For the investigated design, the optimal cathode-anode distance was 12 mm with a step between the turns of the inductor of 6 mm. The results of calculations showed that reducing the distance between the turns of the inductor increases the efficiency of electron cut-off, which confirms the physical adequacy of the mathematical model and the correctness of the calculations. Calculations also showed that at a cathode-anode distance below 12 mm, the focusing of electrons deteriorates.In the proposed design of the VC with the anode inductor in the form of three turns, the complete cut-off of electrons, i.e. the time of flight of electrons through the electrode system, at anode-cathode voltage of 10 kV, occurred by less than 1 ns at an inductor current pulse of 900 A. The inductor current pulse duration was 5 μs had the form of the half-sinusoid arc. The used method of modeling allows to establish in what part of the inductor pulse the full cut-off of electrons is provided.The obtained results can be used in the development of the VC with interruption of the current of vacuum-arc discharge.

Relationship between Speech Perception in Noise and Phonemic Restoration of Speech in Noise in Individuals with Normal Hearing

Background and ObjectivesTop-down restoration of distorted speech, tapped as phonemic restoration of speech in noise, maybe a useful tool to understand robustness of perception in adverse listening situations. However, the relationship between phonemic restoration and speech perception in noise is not empirically clear.Subjects and Methods20 adults (40-55 years) with normal audiometric findings were part of the study. Sentence perception in noise performance was studied with various signal-to-noise ratios (SNRs) to estimate the SNR with 50% score. Performance was also measured for sentences interrupted with silence and for those interrupted by speech noise at -10, -5, 0, and 5 dB SNRs. The performance score in the noise interruption condition was subtracted by quiet interruption condition to determine the phonemic restoration magnitude.ResultsFairly robust improvements in speech intelligibility was found when the sentences were interrupted with speech noise instead of silence. Improvement with increasing noise levels was non-monotonic and reached a maximum at -10 dB SNR. Significant correlation between speech perception in noise performance and phonemic restoration of sentences interrupted with -10 dB SNR speech noise was found.ConclusionsIt is possible that perception of speech in noise is associated with top-down processing of speech, tapped as phonemic restoration of interrupted speech. More research with a larger sample size is indicated since the restoration is affected by the type of speech material and noise used, age, working memory, and linguistic proficiency, and has a large individual variability.

Experimental Investigation of Electrical Stresses on the Main Components of HVDC Circuit Breakers

Recently a number HVdc circuit breakers (CBs) based on various dc current interruption principles have been developed and a few are put in operation. However, due to a lack of practical experience, no clearly defined requirements that the HVdc CBs should satisfy exist. To define and refine justified test requirements, a thorough understanding of the interactions between the internal components of the HVdc CB and the stresses on these components under real dc fault current interruption condition is necessary. In this paper, an experimental dc CB based on the active current injection technique is setup in a high-power laboratory to investigate the performances of the main components; namely, the vacuum interrupter (VI) and the metal oxide surge arrester (MOSA). The performances of three different designs VIs are investigated and it is found out that each of the VIs behave completely different. The key parameters having impact on current interruption performance of the VIs are identified and analyzed in detail. Moreover, the performance of a MOSA, designed for HVdc CB application, is also investigated by applying energy per volume ranging between 70-220 J/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> at temperature as high as 250 °C. In order to find out the performance limit of the MOSA for this application, successive high-energy tests are performed until electro-mechanical failures occur in the MO varistors. Various failure modes such as fracturing and puncture are observed. The detailed analysis of these failure mechanisms during destructive tests and the root causes are presented.