Counting yield correction by an event —time interval—transformation

1977 ◽  
Vol 39 (1-2) ◽  
pp. 163-169 ◽  
Author(s):  
W. Görner
Keyword(s):  
Time Interval ◽  
Event Time ◽  
Counting Yield

scholarly journals Imaging angiogenesis using 68Ga-NOTA-PRGD2 positron emission tomography/computed tomography in patients with severe intracranial atherosclerotic disease

2017 ◽  
Vol 37 (10) ◽  
pp. 3401-3408 ◽  
Author(s):  
Shi Shu ◽  
Li Zhang ◽  
Yi Cheng Zhu ◽  
Fang Li ◽  
Li Ying Cui ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Positron Emission Tomography ◽  
Emission Tomography ◽  
Time Interval ◽  
Arterial Lesion ◽  
Event Time ◽  
Intracranial Atherosclerotic Disease ◽  
Positron Emission ◽  
Recent Group ◽  
The Brain

Angiogenesis is a critical compensation route, which has been demonstrated in the brain following ischemic stroke; however, few studies have investigated angiogenesis in chronic intracranial atherosclerosis disease (ICAD). We used 68Ga-NOTA-PRGD2 positron emission tomography/computed tomography based imaging to detect angiogenesis in chronic ICAD and to explore the factors that may have affected it. A total of 21 participants with unilateral severe chronic ICAD were included in the study. Of the 21 participants, 19 were men; the mean (SD) age was 52 (15) years. In 18 participants, we observed elevated 68Ga-NOTA-PRGD2 uptake in the peri-infarct, subcortical, and periventricular regions of the lesioned side, with a higher 68Ga-NOTA-PRGD2 SUVmax compared to that in the contralateral hemisphere (0.15 vs. 0.06, p=0.001). The 18F-FDG PET SUVmax was significantly lower on the lesioned side (11.28 vs. 13.92, p=0.001). Subgroup analyses revealed that the recent group (<6 months) had a higher lesion-to-contralateral region ratio SUVmax than the remote group (>6 months) (6.73 vs. 2.36, p<0.05). Our results provide molecular imaging evidence of angiogenesis in patients with severe chronic ICAD. Furthermore, the extent of angiogenesis in chronic ICAD may be affected by the post-qualified event time interval, and not by infarction itself or the severity of the arterial lesion.

Controller design for systems subject to multi-layer nested saturation via event-triggered scheme

2020 ◽  
pp. 014233122094048
Author(s):  
Yuan Zhou ◽  
Hongchao Li ◽  
Jiao Liu ◽  
Dedong Yang
Keyword(s):  
Continuous Time ◽  
Optimization Problem ◽  
Final Section ◽  
Controller Design ◽  
Domain Of Attraction ◽  
Time Interval ◽  
Event Time ◽  
Continuous Time Systems ◽  
Time Systems ◽  
Event Triggered

The design of an event-triggered controller to stabilize the continuous-time systems subject to multi-layer nested saturation is presented in this paper. As a complex nonlinearity, the nested saturation exists in a large number of systems, which may degrade the performance of the system. The sufficient condition for stabilization of the multi-layer saturated system is given by employing event-triggered control, which could reduce communication load of the system. The lower bound of the inter-event time interval is calculated to avoid the Zeno behavior. The domain of attraction for the system is estimated, which is determined by solving an optimization problem. The main advantage of the proposed approach lies in the extensive applicability for different layers of the nested saturation. In the final section, simulation and pratical examples are given to demonstrated the effectiveness of the proposed results.

A Denotational Semantics of Real-Time Process Algebra (RTPA)

2011 ◽  
pp. 200-217
Author(s):  
Yingxu Wang ◽  
Xinming Tan
Keyword(s):  
Real Time ◽  
Process Algebra ◽  
Denotational Semantics ◽  
Time Interval ◽  
Time Process ◽  
Denotational Semantic ◽  
Time Intervals ◽  
Event Time ◽  
Driven System ◽  
New Framework

Real-time process algebra (RTPA) is a form of denotational mathematics for dealing with fundamental system behaviors such as timing, interrupt, concurrency, and event/time/interrupt-driven system dispatching. Because some key RTPA processes cannot be described adequately in conventional denotational semantic paradigms, a new framework for modeling time and processes is sought in order to represent RTPA in denotational semantics. Within this framework, time is modeled by the elapse of process execution. The process environment encompasses states of all variables represented as mathematical maps, which project variables to their corresponding values. Duration is introduced as a pair of time intervals and the environment to represent the changes of the process environment during a time interval. Temporal ordered durations and operations on them are used to denote process executions. On the basis of these means, a comprehensive set of denotational semantics for RTPA are systematically developed and formally expressed.

Dynamic event-triggered control for linear systems subject to asymmetric actuator saturation

2021 ◽  
pp. 014233122110592
Author(s):  
Hongchao Li ◽  
Nan Zhang ◽  
Huimin Deng
Keyword(s):  
Actuator Saturation ◽  
Sufficient Conditions ◽  
Stable Region ◽  
Time Interval ◽  
Control Engineering ◽  
Event Time ◽  
Dynamic Event ◽  
System A ◽  
Theoretical Results ◽  
Event Triggered

This paper investigates dynamic event-triggered control for systems subject to asymmetric actuator saturation. The asymmetric saturation could severely degrade the performance of systems, which always exists in control engineering. A dynamic event-triggered scheme considering the character of asymmetric saturation is proposed to reduce triggered number of events, under the premise that the closed-loop system subject to asymmetric actuator saturation is asymptotically stabilized. Sufficient conditions are derived to stabilize the system and the minimum inter-event time interval is calculated to exclude Zeno behaviour. An optimization problem is solved to estimate the contractive invariant set as the stable region of the system. A numerical example is given to illustrate the theoretical results.

Focusing of Visuospatial Attention

2001 ◽  
Vol 15 (4) ◽  
pp. 256-274 ◽  
Author(s):  
Caterina Pesce ◽  
Rainer Bösel
Keyword(s):  
Reaction Times ◽  
Visual Space ◽  
Spatial Relation ◽  
Stimulus Onset ◽  
Visuospatial Attention ◽  
Task Demands ◽  
Time Interval ◽  
Behavioral Studies ◽  
Task Conditions ◽  
Simple Rt

Abstract In the present study we explored the focusing of visuospatial attention in subjects practicing and not practicing activities with high attentional demands. Similar to the studies of Castiello and Umiltà (e. g., 1990) , our experimental procedure was a variation of Posner's (1980) basic paradigm for exploring covert orienting of visuospatial attention. In a simple RT-task, a peripheral cue of varying size was presented unilaterally or bilaterally from a central fixation point and followed by a target at different stimulus-onset-asynchronies (SOAs). The target could occur validly inside the cue or invalidly outside the cue with varying spatial relation to its boundary. Event-related brain potentials (ERPs) and reaction times (RTs) were recorded to target stimuli under the different task conditions. RT and ERP findings showed converging aspects as well as dissociations. Electrophysiological results revealed an amplitude modulation of the ERPs in the early and late Nd time interval at both anterior and posterior scalp sites, which seems to be related to the effects of peripheral informative cues as well as to the attentional expertise. Results were: (1) shorter latency effects confirm the positive-going amplitude enhancement elicited by unilateral peripheral cues and strengthen the criticism against the neutrality of spatially nonpredictive peripheral cueing of all possible target locations which is often presumed in behavioral studies. (2) Longer latency effects show that subjects with attentional expertise modulate the distribution of the attentional resources in the visual space differently than nonexperienced subjects. Skilled practice may lead to minimizing attentional costs by automatizing the use of a span of attention that is adapted to the most frequent task demands and endogenously increases the allocation of resources to cope with less usual attending conditions.

Attention Deficit and Disruptive Behavior Disorder Symptoms

2001 ◽  
Vol 17 (1) ◽  
pp. 25-35 ◽  
Author(s):  
G. Leonard Burns ◽  
James A. Walsh ◽  
David R. Patterson ◽  
Carol S. Holte ◽  
Rita Sommers-Flanagan ◽  
...  
Keyword(s):  
Attention Deficit ◽  
Rating Scales ◽  
Behavior Disorder ◽  
Disruptive Behavior Disorder ◽  
Subjective Rating ◽  
Time Interval ◽  
Assessment Procedure ◽  
Frequency Count ◽  
Hyperactivity Disorder ◽  
Oppositional Defiant

Summary: Rating scales are commonly used to measure the symptoms of attention deficit/hyperactivity disorder (ADHD), oppositional defiant disorder (ODD), and conduct disorder (CD). While these scales have positive psychometric properties, the scales share a potential weakness - the use of vague or subjective rating procedures to measure symptom occurrence (e. g., never, occasionally, often, and very often). Rating procedures based on frequency counts for a specific time interval (e. g., never, once, twice, once per month, once per week, once per day, more than once per day) are less subjective and provide a conceptually better assessment procedure for these symptoms. Such a frequency count procedure was used to obtain parent ratings on the ADHD, ODD, and CD symptoms in a normative (nonclinical) sample of 3,500 children and adolescents. Although the current study does not provide a direct comparison of the two types of rating procedures, the results suggest that the frequency count procedure provides a potentially more useful way to measure these symptoms. The implications of the results are noted for the construction of rating scales to measure the ADHD, ODD, and CD symptoms.

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