390,668 research outputs found
An Intelligent Complex Event Processing with D
Efficient matching of incoming mass events to persistent queries is fundamental to complex event processing systems. Event matching based on pattern rule is an important feature of complex event processing engine. However, the intrinsic uncertainty in pattern rules which are predecided by experts increases the difficulties of effective complex event processing. It inevitably involves various types of the intrinsic uncertainty, such as imprecision, fuzziness, and incompleteness, due to the inability of human beings subjective judgment. Nevertheless, D numbers is a new mathematic tool to model uncertainty, since it ignores the condition that elements on the frame must be mutually exclusive. To address the above issues, an intelligent complex event processing method with D numbers under fuzzy environment is proposed based on the Technique for Order Preferences by Similarity to an Ideal Solution (TOPSIS) method. The novel method can fully support decision making in complex event processing systems. Finally, a numerical example is provided to evaluate the efficiency of the proposed method
Predictive intelligence to the edge through approximate collaborative context reasoning
We focus on Internet of Things (IoT) environments where a network of sensing and computing devices are responsible to locally process contextual data, reason and collaboratively infer the appearance of a specific phenomenon (event). Pushing processing and knowledge inference to the edge of the IoT network allows the complexity of the event reasoning process to be distributed into many manageable pieces and to be physically located at the source of the contextual information. This enables a huge amount of rich data streams to be processed in real time that would be prohibitively complex and costly to deliver on a traditional centralized Cloud system. We propose a lightweight, energy-efficient, distributed, adaptive, multiple-context perspective event reasoning model under uncertainty on each IoT device (sensor/actuator). Each device senses and processes context data and infers events based on different local context perspectives: (i) expert knowledge on event representation, (ii) outliers inference, and (iii) deviation from locally predicted context. Such novel approximate reasoning paradigm is achieved through a contextualized, collaborative belief-driven clustering process, where clusters of devices are formed according to their belief on the presence of events. Our distributed and federated intelligence model efficiently identifies any localized abnormality on the contextual data in light of event reasoning through aggregating local degrees of belief, updates, and adjusts its knowledge to contextual data outliers and novelty detection. We provide comprehensive experimental and comparison assessment of our model over real contextual data with other localized and centralized event detection models and show the benefits stemmed from its adoption by achieving up to three orders of magnitude less energy consumption and high quality of inference
Stress and decision making: a neuroeconomic approach
Two experiments are reported, which test the hypothesis that acute stress leads to suboptimal decisions under uncertainty (outcomes known but not their probabilities), due to a stressor caused bias toward the preference for positive feedbacks. The published literature suggests that acute stress leads to suboptimal decision-making, but only for those subjects who show a strong cortisol response. The stress hormone cortisol biases the reward system towards a preference for positive feedbacks, while ignoring or neglecting negative feedbacks. A critical review of the literature revealed, that this hypothesis has a questionable data basis. Additionally, there is not a single study using a direct cortical index of feedback processing. The Feedback Related Negativity (FRN), a component of the event-related potential, is measured as a direct index of optimal feedback processing. Both experiments used the Social Evaluated Cold Pressure Test (SECPT) as a stress paradigm. The Balloon Analogue Risk Task (BART) was decision-making procedure in experiment 1, whereas experiment 2 used the Iowa Gambling Task (IGT). The FRN was measured contingent on positive and negative feedbacks during the decision tasks. Three groups were analyzed: two SECPT groups (cortisol high vs cortisol low responders), and a control group performing the Social Evaluated Warm Pressure Test. Though all manipulation checks regarding the behavioral and biological results of the acute stressor and the BART or the IGT could be validated empirically, both experiments revealed no influence of the acute stressor on decision making under uncertainty or on feedback processing, as indexed by the FRN. It is concluded that acute stress has no negative influence on decision-making under uncertainty. Possible objections to this conclusion are discussed in the final sections of this thesis, before developing a basic paradigm, which might guide future research in this field
An Asynchronous Kalman Filter for Hybrid Event Cameras
Event cameras are ideally suited to capture HDR visual information without
blur but perform poorly on static or slowly changing scenes. Conversely,
conventional image sensors measure absolute intensity of slowly changing scenes
effectively but do poorly on high dynamic range or quickly changing scenes. In
this paper, we present an event-based video reconstruction pipeline for High
Dynamic Range (HDR) scenarios. The proposed algorithm includes a frame
augmentation pre-processing step that deblurs and temporally interpolates frame
data using events. The augmented frame and event data are then fused using a
novel asynchronous Kalman filter under a unifying uncertainty model for both
sensors. Our experimental results are evaluated on both publicly available
datasets with challenging lighting conditions and fast motions and our new
dataset with HDR reference. The proposed algorithm outperforms state-of-the-art
methods in both absolute intensity error (48% reduction) and image similarity
indexes (average 11% improvement).Comment: 12 pages, 6 figures, published in International Conference on
Computer Vision (ICCV) 202
Transcranial Direct Corrent stimulation (tDCS) of the anterior prefrontal cortex (aPFC) modulates reinforcement learning and decision-making under uncertainty: A doubleblind crossover study
Reinforcement learning refers to the ability to acquire
information from the outcomes of prior choices (i.e.
positive and negative) in order to make predictions on the
effect of future decision and adapt the behaviour basing on
past experiences. The anterior prefrontal cortex (aPFC) is considered
to play a key role in the representation of event value,
reinforcement learning and decision-making. However, a
causal evidence of the involvement of this area in these processes
has not been provided yet. The aim of the study was to
test the role of the orbitofrontal cortex in feedback processing,
reinforcement learning and decision-making under uncertainly.
Eighteen healthy individuals underwent three sessions of
tDCS over the prefrontal pole (anodal, cathodal, sham) during
a probabilistic learning (PL) task. In the PL task, participants
were invited to learn the covert probabilistic stimulusoutcome
association from positive and negative feedbacks in
order to choose the best option. Afterwards, a probabilistic
selection (PS) task was delivered to assess decisions based
on the stimulus-reward associations acquired in the PL task.
During cathodal tDCS, accuracy in the PL task was reduced
and participants were less prone to maintain their choice after
positive feedback or to change it after a negative one (i.e., winstay
and lose-shift behavior). In addition, anodal tDCS affected
the subsequent PS task by reducing the ability to choose the
best alternative during hard probabilistic decisions. In conclusion,
the present study suggests a causal role of aPFC in feedback
trial-by-trial behavioral adaptation and decision-making
under uncertainty
Managing Uncertain Complex Events in Web of Things Applications
A critical issue in the Web of Things (WoT) is the need to process and analyze the interactions of Web-interconnected real-world
objects. Complex Event Processing (CEP) is a powerful technology for analyzing streams of information about real-time distributed events, coming from different sources, and for extracting conclusions from them. However, in many situations these events are not free from uncertainty, due to either unreliable data sources and networks, measurement uncertainty, or to the inability to determine whether an event has actually happened or not. This short research paper discusses how CEP systems
can incorporate different kinds of uncertainty, both in the events and in the rules. A case study is used to validate the proposal, and we discuss the benefits and limitations of this CEP extension.Universidad de Málaga. Campus de Excelencia Internacional AndalucĂa Tech
The GPU vs Phi Debate: Risk Analytics Using Many-Core Computing
The risk of reinsurance portfolios covering globally occurring natural
catastrophes, such as earthquakes and hurricanes, is quantified by employing
simulations. These simulations are computationally intensive and require large
amounts of data to be processed. The use of many-core hardware accelerators,
such as the Intel Xeon Phi and the NVIDIA Graphics Processing Unit (GPU), are
desirable for achieving high-performance risk analytics. In this paper, we set
out to investigate how accelerators can be employed in risk analytics, focusing
on developing parallel algorithms for Aggregate Risk Analysis, a simulation
which computes the Probable Maximum Loss of a portfolio taking both primary and
secondary uncertainties into account. The key result is that both hardware
accelerators are useful in different contexts; without taking data transfer
times into account the Phi had lowest execution times when used independently
and the GPU along with a host in a hybrid platform yielded best performance.Comment: A modified version of this article is accepted to the Computers and
Electrical Engineering Journal under the title - "The Hardware Accelerator
Debate: A Financial Risk Case Study Using Many-Core Computing"; Blesson
Varghese, "The Hardware Accelerator Debate: A Financial Risk Case Study Using
Many-Core Computing," Computers and Electrical Engineering, 201
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