Adaptive Recovery Research Articles

Segmentation of left ventricle in short-axis echocardiographic sequences by weighted radial edge filtering and adaptive recovery of dropout regions

In this paper, we present a weighted radial edge filtering algorithm with adaptive recovery of dropout regions for the semi-automatic delineation of endocardial contours in short-axis echocardiographic image sequences. The proposed algorithm requires minimal user intervention at the end diastolic frame of the image sequence for specifying the candidate points of the contour. The region of interest is identified by fitting an ellipse in the region defined by the specified points. Subsequently, the ellipse centre is used for originating the radial lines for filtering. A weighted radial edge filter is employed for the detection of edge points. The outliers are corrected by global as well as local statistics. Dropout regions are recovered by incorporating the important temporal information from the previous frame by means of recursive least squares adaptive filter. This ensures fairly accurate segmentation of the cardiac structures for further determination of the functional cardiac parameters. The proposed algorithm was applied to 10 data-sets over a full cardiac cycle and the results were validated by comparing computer-generated boundaries to those manually outlined by two experts using Hausdorff distance (HD) measure, radial mean square error (rmse) and contour similarity index. The rmse was 1.83 mm with a HD of 5.12 ± 1.21 mm. We have also compared our results with two existing approaches, level set and optical flow. The results indicate an improvement when compared with ground truth due to incorporation of temporal clues. The weighted radial edge filtering algorithm in conjunction with adaptive dropout recovery offers semi-automatic segmentation of heart chambers in 2D echocardiography sequences for accurate assessment of global left ventricular function to guide therapy and staging of the cardiovascular diseases.

Beyond acute social stress: Increased functional connectivity between amygdala and cortical midline structures

Whereas we know a fair amount on the role of the amygdala in the acute stress response, virtually nothing is known about its role during the recovery period after the stress has waned. Functional connectivity analysis of the amygdala during this period might be useful in revealing brain circuits promoting adaptive recovery from a stressful event, as well as consolidation of emotionally relevant information in preparing for future challenges. Healthy participants were randomly assigned to either a psychosocial stress task (n=18; stress group) or a comparable non-stressful control procedure (n=20; controls). To study the prolonged effects of stress on amygdala functional connectivity, resting-state fMRI scans were acquired an hour after the stress task. Amygdala functional connectivity with other brain regions was assessed using seed-based correlations. The stress group exhibited a strong physiological and behavioral reaction to psychosocial stress exposure. Compared with controls the stress group showed increased amygdala functional connectivity with three cortical midline structures: the posterior cingulate cortex and precuneus (p<.05, corrected), and the medial prefrontal cortex (p<.05, small volume corrected). An hour after psychosocial stress, changes in amygdala functional connectivity were detected with cortical midline structures involved in the processing and regulation of emotions, as well as autobiographical memory. It is hypothesized that these effects could relate to top-down control of the amygdala and consolidation of self-relevant information after a stressful event. These results on functional connectivity in the recovery phase after stress might provide an important new vantage point in studying both sensitivity and resilience to stress.

Adaptive Clock Recovery Mechanism Having Dynamic Frequency Drift and Buffer Level Control in Packet Switched Networks

Adaptive clock recovery is required in order to transmit the synchronous data of conventional time-division multiplexing (TDM) services to another TDM network across an asynchronous packet switched network (PSN). In this paper, we propose an adaptive clock recovery mechanism having dynamic frequency drift, which enables faster response with smaller residual variance, and buffer level control to reduce the required jitter buffer size with no buffer underflow or overflow.

구조화된 Peer-to-Peer 네트워크를 위한 적응적 링크 복구 주기 결정 알고리듬

Structured P2P (peer-to-peer) networks have received much attention in research communities and the industry. The data stored in structured P2P networks can be located in a log-scale time without using central severs. The link-structure of structured P2P networks should be maintained for keeping log-scale search performance of it. When nodes join or leave structured P2P networks frequently, some links become unavailable and search performance is degraded by these links. To sustain search performance of structured P2P networks, periodic link recovery scheme is generally used. However, when the link recovery period is short or long compared with node join and leave rates, it is possible that sufficient number of links are not restored or excessive messages are used after the link-structure is restored. We propose the adaptive link recovery determination algorithm to maintain the link-structure of structured P2P networks when the rates of node joining and leaving are changed dynamically. The simulation results show that the proposed algorithm can maintain similar QoS under various node leaving rates.

Positive emotional style and subjective, cardiovascular and cortisol responses to acute laboratory stress

The relationships between positive emotional style and acute salivary cortisol and cardiovascular responses to laboratory stress tasks were examined in 40 young women (mean age=28.8 years). Positive emotional style (PES) was measured by aggregating daily positive mood rating scales over one week. Negative affect was assessed with the short form Profile of Mood States. Salivary cortisol was measured in response to two behavioural tasks, a 5 min speech task and a 5 min mirror tracing task. Blood pressure (BP) and heart rate responses were monitored using a Finometer during baseline, tasks and recovery. Higher PES was associated with more complete diastolic BP recovery (p=0.027) and lower acute cortisol response to stress (p=0.018), after adjusting for baseline measures, age, BMI and negative affect. Individuals with higher PES reported lower subjective tension during the tasks and perceived the tasks as more controllable. There were no differences in ratings of task involvement or in objective measures of task performance. A retrospective measure of positive affect (POMS vigour) was associated with diastolic BP recovery but not cortisol responses or subjective tension. The findings suggest that positive affective traits, assessed using repeated assessments of daily mood, are related to adaptive recovery from acute psychological stress. Our results reinforce evidence linking positive affect with adaptive diastolic BP recovery, while extending the results to cortisol. Investigations into the biological correlates of affective traits should consider utilising repeated measures of experienced affect.

Fast and adaptive browsing state recovery for multimedia consumer electronics devices

Most multimedia consumer electronics (CE) devices, such as smart phones, MP3 players, PMPs, and digital cameras, allow users to search and browse multimedia contents stored in the device. For multimedia CE devices, there are two important requirements: (1) the search results displayed in the browser screen must be restored when the device is turned off and later turned back on, and (2) the search results displayed in the browser screen must be updated dynamically to reflect data changes made by other applications. These two requirements have been handled in rather ad-hoc and inefficient manners until now. In this paper, we propose an efficient and systematic solution to meet the two requirements. The proposed solution enables us to save the current browsing state so that the search results displayed in the browser screen can be restored instantly at a later time. Furthermore, the proposed solution restores the browsing state adaptively to reflect data changes made after saving. Through performance evaluation in a real multimedia CE device, we show that the proposed method provides excellent performance compared to existing methods.

Spatial error concealment with sequence-aligned texture modeling and adaptive directional recovery

A spatial error concealment technique based on the sequence-aligned texture modeling and the adaptive directional recovery is proposed in this work. The sequence alignment technique captures the local variation and the global trend of image textures with surrounding uncorrupted pixels, and provides the best texture model under a given cost function. With the derived texture model, geometric interpolation is used to recover lost pixels adaptively based on pixel locations. There are four candidate modes of pixel sequences to recover lost pixels, and one of them is selected for the concealment purpose. The selection criterion is based on the texture pattern modes of surrounding uncorrupted blocks. The pixel sequences used for error concealment can be obtained from the computation of the decoder or the side information from the encoder. Extensive experimental results are given to demonstrate that our error concealment technique outperforms several benchmark methods in both objective and subjective tests.

Selective sweeps and parallel mutation in the adaptive recovery from deleterious mutation in Caenorhabditis elegans

Deleterious mutation poses a serious threat to human health and the persistence of small populations. Although adaptive recovery from deleterious mutation has been well-characterized in prokaryotes, the evolutionary mechanisms by which multicellular eukaryotes recover from deleterious mutation remain unknown. We applied high-throughput DNA sequencing to characterize genomic divergence patterns associated with the adaptive recovery from deleterious mutation using a Caenorhabditis elegans recovery-line system. The C. elegans recovery lines were initiated from a low-fitness mutation-accumulation (MA) line progenitor and allowed to independently evolve in large populations (N ∼ 1000) for 60 generations. All lines rapidly regained levels of fitness similar to the wild-type (N2) MA line progenitor. Although there was a near-zero probability of a single mutation fixing due to genetic drift during the recovery experiment, we observed 28 fixed mutations. Cross-generational analysis showed that all mutations went from undetectable population-level frequencies to a fixed state in 10-20 generations. Many recovery-line mutations fixed at identical timepoints, suggesting that the mutations, if not beneficial, hitchhiked to fixation during selective sweep events observed in the recovery lines. No MA line mutation reversions were detected. Parallel mutation fixation was observed for two sites in two independent recovery lines. Analysis using a C. elegans interactome map revealed many predicted interactions between genes with recovery line-specific mutations and genes with previously accumulated MA line mutations. Our study suggests that recovery-line mutations identified in both coding and noncoding genomic regions might have beneficial effects associated with compensatory epistatic interactions.

A COX‐2 inhibitor reduces muscle soreness, but does not influence recovery and adaptation after eccentric exercise

The aim of this study was to investigate the effect of a cyclooxygenase (COX)-2 inhibitor on the recovery of muscle function, inflammation, regeneration after, and adaptation to, unaccustomed eccentric exercise. Thirty-three young males and females participated in a double-blind, placebo-controlled experiment. Seventy unilateral, voluntary, maximal eccentric actions with the elbow flexors were performed twice (bouts 1 and 2) with the same arm, separated by 3 weeks. The test group participants were administered 400 mg/day of celecoxib for 9 days after bout 1. After both bouts 1 and 2, concentric and isometric force-generating capacity was immediately reduced (approximately 40-50%), followed by the later appearance of muscle soreness and increased serum creatine kinase levels. Radiolabelled autologous leukocytes (detected by scintigraphy) and monocytes/macrophages (histology) accumulated in the exercised muscles, simultaneously with increased satellite cell activity. These responses were reduced and recovery was faster after bout 2 than 1, demonstrating a repeated-bout effect. No differences between the celecoxib and placebo groups were detected, except for muscle soreness, which was attenuated by celecoxib. In summary, celecoxib, a COX-2 inhibitor, did not detectably affect recovery of muscle function or markers of inflammation and regeneration after unaccustomed eccentric exercise, nor did the drug influence the repeated-bout effect. However, it alleviated muscle soreness.

Temporal error concealment algorithm designed for H.264

To overcome the degradation of video quality caused by transmission errors,a new temporal error concealment algorithm based on motion vector adaptive recovery was proposed,which efficiently exploited the characteristic of H.264.Firstly the Motion Vector Relative Strength(MVRS) was estimated by calculating a ratio involving the motion vectors of adjacent macro blocks.Then either minimum variance of boundary motion vectors method or polynomial interpolation method was employed to recover the lost motion vectors according to the magnitude of MVRS.The simulation results show that the proposed algorithm can highly improve the quality of reconstructed video and obtain a gain of about 0.2~2.5dB in PSNR,compared with conventional temporal error concealment algorithms in the condition of equal packet loss rate.

Toward Neural Networks Solution for Multimedia Support in Mobile Ad hoc Networks

In this paper, we detail an integrated model for quality of service (QoS) support with service differentiation based on neural networks in wireless mobile ad hoc networks. The model aims at minimizing end-to-end delay for real-time traffic when the network has low to medium dynamics. The use of multi-service classes allows per-flow end-to-end QoS support. The operation of the model is based on a set of core functionality that is augmented with an intelligent learning layer. Core operations ensure different tasks of routing and QoS support control such as route discovery, resources reservation, admission control, traffic adaptation and detection and recovery of QoS violation. The added intelligent layer learns from the different operations performed by the core functionality by means of a Multilayered Feedforward Neural Network according to user requirements and network state. The integrated model showed in simulations that the core functionality together with the intelligent learning improve the quality of data delivery in the network comparatively to models such as SWAN. Te effect of the learning rate on the convergence of network training was also examined. Using intelligent neural networks tools to support the multimedia services in ad hoc networks is a promising avenue.

Adaptive address energy recovery circuit for reducing address power in color PDPs

An adaptive address energy recovery circuits (AAERCs) for plasma display panels (PDPs) is proposed after analyzing the address power of address methods such as the address energy recovery circuits (AERCs), no-AERC, and interlaced/progressive scan (IPS). Also the detecting method for change rate of address data to calculate address power is proposed. Then AAERCs can work as AERCs, no-AERCs, or IPS in one subfield according to calculating result of address power to get the lowest address power comparing with other methods. There is no change on prototype address circuit but only control timing of scan ICs and address data processing in software. The experiment results with a 50-in. HD dual-scan PDP shows that the address power of AAERCs can keep the lowest at any picture comparing with other address methods, and the maximum address power saved is 81 W.

Energy efficient redundant configurations for real-time parallel reliable servers

Modular redundancy and temporal redundancy are traditional techniques to increase system reliability. In addition to being used as temporal redundancy, with technology advancements, slack time in a system can also be used by energy management schemes to save energy. In this paper, we consider the combination of modular and temporal redundancy to achieve energy efficient reliable real-time service provided by multiple servers. We first propose an efficient adaptive parallel recovery scheme that appropriately processes service requests in parallel to increase the number of faults that can be tolerated and thus system reliability. Then we explore schemes to determine the optimal redundant configurations of the parallel servers to minimize system energy consumption for a given reliability goal or to maximize system reliability for a given energy budget. Our analysis results show that small requests, optimistic approaches, and parallel recovery favor lower levels of modular redundancy, while large requests, pessimistic approaches and restricted serial recovery favor higher levels of modular redundancy.

Dark adaptation recovery of human rod bipolar cell response kinetics estimated from scotopic b‐wave measurements

We recorded ganzfeld scotopic ERGs to examine the responses of human rod bipolar cells in vivo, during dark adaptation recovery following bleaching exposures, as well as during adaptation to steady background lights. In order to be able to record responses at relatively early times in recovery, we utilized a 'criterion response amplitude' protocol in which the test flash strength was adjusted to elicit responses of nearly constant amplitude. In order to provide accurate and unbiased measures of response kinetics, we utilized a curve-fitting procedure to fit a smooth function to the measured responses in the vicinity of the peak, thereby extracting both the time-to-peak and the amplitude of the responses. Following bleaching exposures, the responses exhibited both desensitization and accelerated kinetics. During early post-bleach recovery, the flash sensitivity and time-to-peak varied according to a power-law expression (with an exponent of 6), as found in the presence of steady background light. This light-like phenomenon, however, appeared to be set against the backdrop of a second, more slowly recovering 'pure' desensitization, most clearly evident at late post-bleach times. The post-bleach 'equivalent background intensity' derived from measurements of flash sensitivity faded initially with an S2 slope of approximately 0.24 decades min(-1), and later as a gentle S3 tail. When calculated from kinetics, the results displayed only the S2 slope. While the recovery of rod bipolar cell response kinetics can be described accurately by a declining level of opsin in the rods, the sensitivity of these cells is reduced further than expected by this mechanism alone.

Outcomes of Trauma Treatment Using the TARGET Model

ABSTRACT In a randomized trial of a group intervention for co-occurring substance abuse and traumatic stress disorders “Trauma Adaptive Recovery Group Education and Therapy” (TARGET) was compared to trauma-sensitive usual care (TSU) with 213 clients in three adult outpatient clinics. Improvement at 6- and 12-month assessments occurred across conditions. TARGET was superior to TSU in maintaining sobriety self-efficacy. However, ethnic differences emerged. White TARGET participants reported more improvement than non-White participants on post-traumatic cognitions, and fewer non-White men reported relapses in TSU than in TARGET. TARGET appears to enhance sustained sobriety, but may require culturally specific adaptations.

Negative Acceleration and Adaptive Automation Approaches to Counter the Effect of Acceleration Induced Loss of Consciousness

Gravity-induced loss of consciousness (GLOC) is a major human factors problem facing fighter pilots today. A recent study by Tripp et al. (2006) reported that the GLOC episode consists of 24 sec of unconsciousness and confusion/disorientation followed by 55 sec in which performance efficiency is compromised. Hence, fighter pilots in the throes of GLOC can travel 12 miles while not in control of their aircraft. Using a centrifuge to simulate gravitational forces together with tracking and math tasks to simulate flight control and navigation, this study attacked the GLOC problem in two ways: (1) by employing negative acceleration following GLOC onset to decrease GLOC recovery time and (2) by assessing the utility of a of cerebral tissue oxygen saturation (rSO2) measure as a possible triggering mechanism for an adaptive automation recovery system. Negative acceleration had no significant effect on the duration of the GLOC episode. Declines in rSO2 from baseline pinpointed when pilots would cease active flight control and when GLOC would set in. Thus, the rSO2 measure may be of effective value as an adaptive automation GLOC recovery system trigger. The rSO2 measure also showed that loss of blood oxygen is not the sole factor underlying performance deficits in GLOC. Tissue oxygen saturation retuned to baseline levels shortly after the centrifuge came to a complete stop following GLOC onset but the performance deficits continued for 55 sec after rSO2 returned to baseline. Cleared for Public Release Distribution Unlimited

In Vivo Toxicity Study of Rhodamine 6G in the Rat Retina

To investigate the intraocular effect of rhodamine 6G (R6G) on retinal structures and function in an in vivo rat model and to develop an in vivo method for accurate evaluation of new dyes for intraocular surgery. R6G in physiologic saline solution (PSS) was injected into the vitreous of adult Brown Norway rats at concentrations of 0.0002%, 0.002%, 0.02%, 0.2%, and 0.5%. Control animals received only PSS. Retinal toxicity was assessed by retinal ganglion cell (RGC) counts, light microscopy 7 days later, photopic electroretinography (ERG), and measurement of scotopic sensitivity and recovery of dark adaptation 48 hours and 7 days after intravitreous injection. R6G at concentrations of 0.2% and 0.5% led to a dose-dependent loss of RGC. The most significant loss occurred at 0.5%. Lower concentrations (0.0002%, 0.002%, and 0.02%) produced no statistically significant retinal ganglion cell loss. Analysis of the eyes by light microscopy showed no structural changes in the central retina, although injections of 0.5% R6G were followed by impressive degenerative changes adjacent to the injection sites. ERGs showed no effects of the highest R6G concentration on rods, kinetics of rhodopsin recovery after bleaching, or cone-driven responses. R6G can be safely injected in doses of up to 0.02% in rats, but has a toxic effect on retinal ganglion cells at higher concentrations. Accumulation of R6G may be a problem at higher concentrations, particularly at the injection site.

A Robust and Adaptive Carrier Recovery Method for Chinese DTTB Receiver

This paper presents a robust and adaptive carrier recovery method for Chinese digital terrestrial television broadcasting (DTTB) system in which pilot signal and pseudonoise (PN) sequence are adopted to help carrier recovery. The conventional methods utilize pilot or PN sequence respectively. In this paper, we try to combine the advantage of each method together and propose a well designed state machine to control system state automatically. Moreover, as for using PN sequence, a fine PN tracking state is introduced to ensure the robustness of the proposed method. Software simulations show that the proposed method can provide large acquisition range, short acquisition time and small tracking jitter in severely distorted static and dynamic channels. Lab tests and field trials also prove its good performance in real propagation environments.

Adaptive Carrier Synchronization Using Decision-Aided Kalman Filtering Algorithms

A new adaptive carrier recovery algorithm is proposed by using the decision-aided extended Kalman filtering technique. In order to reduce computational complexity of the Kalman recursions, the state model in the new algorithm uses only phase rather than both phase and frequency which are usually used in conventional modeling. The frequency is considered as an input term to the system equation and estimated by a phase error detector. A reduced observation model is also introduced to relieve computing load from multiple matrix to scalar operations in the Kalman recursions. Simulations show that the proposed one-state Kalman algorithm has better performance and lower complexity than the two-state Kalman algorithm for synchronization applications. The new algorithm is applied to the cable modem downstream system to demonstrate its effectiveness with FPGA implementation results.

Built-in Self-test and Defect Tolerance in Molecular Electronics-based Nanofabrics

We propose a built-in self-test (BIST) procedure for nanofabrics implemented using chemically assembled electronic nanotechnology. Several fault detection configurations are presented to target stuck-at faults, shorts, opens, and connection faults in nanoblocks and switchblocks. The detectability of multiple faults in blocks within the nanofabric is also considered. We present an adaptive recovery procedure through which we can identify defect-free nanoblocks and switchblocks in the nanofabric-under-test. The proposed BIST, recovery, and defect tolerance procedures are based on the reconfiguration of the nanofabric to achieve complete fault coverage for different types of faults. We show that a large fraction of defect-free blocks can be recovered using a small number of BIST configurations. We also present simple bounds on the recovery that can be achieved for a given defect density. Simulation results are presented for various nanofabric sizes, different defect densities, and for random and clustered defects. The proposed BIST procedure is well suited for regular and dense architectures that have high defect densities.