Incoherent Information Research Articles

Separating aleatory and epistemic uncertainties: Probabilistic sewer flooding evaluation using probability box

Summary Uncertainty is generally present in flood evaluation and can be divided into aleatory and epistemic categories. It is not uncommon that flood evaluation has to consider both aleatory and epistemic uncertainties when a simulation model is used. This paper presents a probability box methodology that enables various representations of uncertainty to be simultaneously propagated through a model while separation of aleatory and epistemic uncertainties is preserved in the model output. The proposed methodology is applied to a sewer flood evaluation problem, in which rainfall variables are characterized by probability boxes and two model parameters are respectively described by fuzzy sets and random sets. Consequently, the probabilistic flood evaluation is expressed by probability boxes. Simulation results demonstrate the critical importance of separating aleatory and epistemic uncertainties and of maintaining the uncertainty type (either aleatory or epistemic) in uncertainty propagation. It is suggested that the pooling of aleatory and epistemic uncertainties may lead to incoherent information in the model output.

Error monitoring functions in response to an external feedback when an explicit judgement is required: ERP modulation and cortical source localisation

Individuals need feedback from the context to determine the success of their actions. In the present study, the explicit process of the feedback judgement (explicit response to feedback correctness) was examined by recording ERPs. A systematic mismatch between the expected feedback information and the observed feedback (incorrect feedback) linked to the subject's performance was used. Thirteen subjects participated in the study, and they were required to detect the correct vs. incorrect feedback with an explicit response. The experimental procedure included three main tasks: the subject's performance (spatial decisional task); the system's response to the performance (external feedback); and the subject's judgement of the external feedback (feedback monitoring). A FRN (feedback-related negativity) ERP effect with a higher amplitude was revealed in case of an explicit feedback monitoring for the incorrect feedback. Moreover, as shown by the cortical source analysis (LORETA), monitoring of an erroneous feedback produced a significant increased response by the right prefrontal area. This negative deflection may be viewed as a specific marker of the conscious monitoring functions. Considering the cortical distribution of this effect, whereas the anterior portion of the cingulate cortex could represent a more automatic cognitive processing of a mismatching, the anterior right dorsolateral area would intervene to reconfigure the subjective expectations when a violation is consciously detected. Generally, this system could explain the significance of the mechanism to the erroneous feedback and the necessity to restore the incoherent information.

Atypicality and the two fundamental dimensions: Applying the negativity effect on warmth to group perception

AbstractThe person perception literature has shown that negative information on warmth influences impression formation more than other kinds of information. In the present paper, we argue for the usefulness of using the knowledge accumulated on the negativity effect on warmth when studying how members of a group who are disconfirming the group stereotype are perceived. We show that negative divergent information on warmth is perceived as more surprising because it appears to be more discrepant than positive divergent information on warmth or than competence information. We also show how stereotype holders protect their stereotype by rating the surprising incoherent information as atypical. Results are discussed in terms of the necessity to apply our knowledge of the two fundamental dimensions of social perception and their properties to typicality ratings and, beyond them, to stereotype change research. Copyright © 2009 John Wiley & Sons, Ltd.

Depth classification based solely on incoherent sonar information

Most work on sonar contact depth estimation has been based on deterministic, coherent propagation modeling of the sound channel, e.g., matched-field processing. This has met with limited success due to the inability to precisely predict the sound-pressure field in realistic scenarios. This paper addresses the problem of using probabilistic, incoherent information from the sonar itself for depth classification with active sonar, without having to depend on precise and accurate propagation models and ancillary environmental measurements. In particular, the problem of deciding whether or not a given contact is on the bottom based solely on the sonar data is looked at, i.e., without resorting to the use of any additional environmental measurements or predictive models. To do this, the in situ local bottom reverberation is used to calibrate the channel. Probability theory is explored to provide a theoretical basis for the development of a single-hypothesis decision metric to best exploit this information. The methods are tested on a combination of broadband sonar data and detailed ocean simulations. The particular metric proposed for this problem seems to be important for achieving good performance, and may be of some interest in its own right for other types of single-hypothesis decision problems.

Eight questions about Semantic Web annotations

Improving information retrieval is one of the central goals of annotation. However, without clear guidelines, annotation risks producing incoherent information. The author recommends answering eight key questions before annotation begins: (1) What aspect of the content must be represented? (2) What are the subject and form of the knowledge to represent? (3) Are annotations only descriptions? (4) Must we reify some classes in descriptions? (5) Is some background knowledge necessary? (6) Is the background knowledge part of the ontology? (7) Can the background knowledge and ontology evolve? (8) Is the Semantic Web common knowledge or distributed knowledge?.

Eight questions about Semantic Web annotations

Improving information retrieval is one of the central goals of annotation. However, without clear guidelines, annotation risks producing incoherent information. The author recommends answering eight key questions before annotation begins: (1) What aspect of the content must be represented? (2) What are the subject and form of the knowledge to represent? (3) Are annotations only descriptions? (4) Must we reify some classes in descriptions? (5) Is some background knowledge necessary? (6) Is the background knowledge part of the ontology? (7) Can the background knowledge and ontology evolve? (8) Is the Semantic Web common knowledge or distributed knowledge?.

Federal sector

Atkiss outlines the development of the Federal Publishers Committee as a response to common problems of publishers in federal agencies — costs, production, mailing lists, postage, and fee vs. free. He also points out the difficulties facing federal agencies in operating under an incoherent information policy.

Optical Processing Of Photographic Images

Recent advances in electro-optics have brought into use communication and information theory to analyze performance in coherent and incoherent optical information processing systems. An optical information processsing system can be analyzed with many of the same concepts of linear system theory (e.g., spatial impulse response, spatial frequency and spatial domain synthesis, etc.), and the photographic images to be processed can be regarded in the same manner as time signals (e.g., spatial frequency content, spatial amplitude and phase modulation, space-bandwidth product, etc.). Both coherent and incoherent optical processing systems can be treated as linear systems, and the processing operation can generally be carried out by communication theory concepts. Although coherent optical information processing operations have been used for performing complex amplitude operations, complex processing can also be performed with incoherent or white-light illumination. The importance of optical information processing operations, either coherent or incoherent, is due to the basic Fourier transform properties of lenses. In this paper, we will discuss mostly the incoherent systems because they are of more recent interest and possess certain advantages, we feel, over the traditional coherent optical processors. Experimental illustrations of the results are provided. In view of the broad area in optical processing of photographic images, we will confine ourselves to a few applications that we consider of general interest. We apologize for the omission of other techniques and applications, and for neglecting the inclusion of their references.

Implementation of an incoherent optical image restoration method: limitations related to optical subtraction

Incoherent optical information processing is known to be far less sensitive to noise than coherent processing. However, it is restricted to real non-negative quantities. In cases like approximate deconvolution for image restoration, where positive and negative quantities are involved, the use of incoherent illumination is possible only at the expense of some additional sophistication needed to incorporate the negative parts; in particular, the restoration can be achieved by combining two incoherent convolutions and one subtraction. This paper describes an experiment of this type, with special emphasis on the practical implementation and on the difficulties related to the subtraction. Alignment and normalization of the two images to be subtracted are critical issues. If the subtraction is performed optically, the dynamic range of this operation is an additional problem.

Investigation of Means of Improving the Accuracy of Matrix Calculations in Optical Incoherent System

Matrix calculation errors in the authors' non-coherent optical system are analysed in the paper. It is stated that the use of an illuminated diffuser as an extended source may result in a considerable calculation error (up to 7 per cent). Its behaviour is defined by a generalized scattering diagram of the extended source, i.e. by function, which takes into account the diffuser scattering properties and illuminating beam configuration. The requirements for the choice of the characteristics of this illuminator are settled. An illuminator is proposed which application, together with a compensating mask, allows one to reduce the error component to a minimum, according to computer calculations. Experiments performed point to the possibility of substantially diminishing this error. It is stated that, with the account of other components, the total calculation error can be reduced to 1 per cent and even less. The results obtained can be applied to the use of existing incoherent information processing systems, an...

An Estimation Technique Applied to Failure Detection

To control a dynamic system in presence of sensor failures, the usual approach introduces three sensors for each important output and a voting procedure to select the correct information. The authors propose to replace the third sensor by estimations of the output measurements that express the natural redundancy of the outputs of the system.Obviously, these estimations must not be disturbed by any failure. Among several possibilities, the authors have chosen a method that rejects the incoherent information detected by the two sets of sensors, until the correct sensor is selected. Such a solution is a nonstationary one because of the modifications of the observation equation. In order to reduce the computation time, a bank of stationary filters adapted to each particular configuration of the data acquisition system was used.In the practical example solved, automatic landing of the AIRBUS aircraft, the authors have to deal with new difficulties : a part of the system itself is nonstationary. So a separation into a large stationary system and the remaining one, nonlinear and nonstationary, is done.Good results are obtained with a computation time not too large for an onboard computer.