An Efficient Representation Format for Fuzzy Intervals Based on Symmetric Membership Functions

International audienceThis paper proposes a novel implementation of fuzzy arithmetics that exploits both fuzzy intervals and hardware specificities. First, we propose and evaluate the benefit of an alternative representation format to the traditional lower-upper and midpoint-radius representation formats for intervals. Thanks to the proposed formats, we show that it is possible to halve the number of operations and memory requirements compared to conventional methods. Then, we show that operations on fuzzy intervals are sensitive to hardware specificities of accelerators such as GPU. These include static rounding, memory usage, instruction level parallelism (ILP) and thread-level parallelism (TLP). We develop a library of fuzzy arithmetic operations in CUDA and C++ over several formats. The proposed library is evaluated using compute-bound and memory-bound benchmarks on Nvidia GPUs, and shows a performance gain of 2 to 20 over traditional approaches

Extended gradual interval (EGI) arithmetic and its application to gradual weighted averages

International audienceWe combine the concepts of gradual numbers and Kaucher arithmetic on extended intervals to define extended gradual interval (EGI) arithmetic in which subtraction and division operators are the inverse operators of addition and multiplication, respectively. Use of the proposed EGI operators can lead to non-monotonic gradual intervals that are not fuzzy subsets and cannot be represented by fuzzy intervals. In this context and when fuzzy representation results are desired, an approximation strategy is proposed to determine the nearest fuzzy interval of the non-monotonic gradual interval obtained. This approximation is viewed as an interval regression problem according to an optimization procedure. The EGI operators are applied to the common fuzzy weighted average (FWA) leading to a gradual weighted average (GWA)

A study of event-related electrocortical oscillatory dynamics associated with cued motor-response inhibition during performance of the Go/NoGo task within a sample of prenatally alcohol-exposed children and age-matched controls

Fetal alcohol spectrum disorders (FASDs) are a spectrum of disorders that occur due to prenatal alcohol exposure (PAE). Response inhibition refers to the ability to inhibit/suppress a prepotent behavioural tendency set in motion during an experimental task. Our research explored neocortical processing in heavy-exposed children from Cape Town, South Africa, performing the Go/NoGo response inhibition task. We utilised event-related electroencephalographic methodologies to examine event-related potentials (ERP) and eventrelated changes in induced oscillatory power - event-related desynchronisation (ERD)/eventrelated synchronisation (ERS). Across visual and auditory Go/NoGo tasks, we observed equivalent levels of inhibitory control between heavy-exposed (HE) participants and normally-developing controls; however, HEs demonstrated significantly slower reaction times relative to the control group. In an auditory ERP study, we observed a number of alcohol-related changes in ERP waveform morphology, such as decreased P2 amplitude, reduced P3 amplitude, and longer P3 peak latency. In addition, within the HE group, late in the trials, a slow-wave component was observed in both experimental conditions. A significant difference in N2 amplitude across conditions that has consistently been observed in normally-developing samples was not observed in the HE group. We extended previous research findings in the visual domain by analysing induced oscillatory responses. We observed within the normally-developing sample: (1) in both experimental conditions, a frontal induced beta-band ERS related to decision-making; and (2) in the NoGo-condition, a frontal gamma-band ERS related to cognitive-control. Within the HE group, the beta-ERS was not observed in either of the experimental conditions, neither was the gamma-ERS observed in the NoGo-condition. Frontal induced beta-power was predictive of performance accuracy in the HE group, but not in the control group. The observed alcohol-related effects were not explained and/or mediated by IQ (WISC-IQ), socio-economic circumstances, comorbid ADHD, or teratogenic effects related to postnatal lead exposure and prenatal cigarette-smoke exposure. Our results point to alterations in scalp-measured event-related neocortical oscillatory dynamics and slower processing of task demands due to heavy PAE. These alcohol-related effects are observable on ERP component measures, primarily related to conflict-monitoring and attention-based processing. PAE also affects induced classes of neocortical oscillatory dynamics related to decision-making and cognitive-control processes required to inhibit a prepotent motor-response

The Transverse-Field Ising Spin Glass Model on the Bethe Lattice with an Application to Adiabatic Quantum Computing

In this Ph.D. thesis we examine the Adiabatic Quantum Algorithm from the point of view of statistical and condensed matter physics. We do this by studying the transverse-field Ising spin glass model defined on the Bethe lattice, which is of independent interest to both the physics community and the quantum computation community. Using quantum Monte Carlo methods, we perform an extensive study of the the ground-state properties of the model, including the R\'enyi entanglement entropy, quantum Fisher information, Edwards--Anderson parameter, correlation functions. Through the finite-size scaling of these quantities we find multiple independent and coinciding estimates for the critical point of the glassy phase transition at zero temperature, which completes the phase diagram of the model as was previously known in the literature. We find volumetric bipartite and finite multipartite entanglement for all values of the transverse field considered, both in the paramagnetic and in the glassy phase, and at criticality. We discuss their implication with respect to quantum computing. By writing a perturbative expansion in the large transverse field regime we develop a mean-field quasiparticle theory that explains the numerical data. The emerging picture is that of degenerate bands of localized quasiparticle excitations on top of a vacuum. The perturbative energy corrections to these bands are given by pair creation/annihilation and hopping processes of the quasiparticles on the Bethe lattice. The transition to the glassy phase is explained as a crossing of the energy level of the vacuum with one of the bands, so that creation of quasiparticles becomes energetically favoured. We also study the localization properties of the model by employing the forward scattering approximation of the locator expansion, which we compute using a numerical transfer matrix technique. We obtain a lower bound for the mobility edge of the system. We find a localized region inside of the glassy phase and we discuss the consequences of its presence for the Adiabatic Quantum Algorithm

The development of improved timing systems for rapid and precise astronomical fixation in mining exploratory surveying

Imperial Users onl

Forecasting CO2 Sequestration with Enhanced Oil Recovery

The aim of carbon capture, utilization, and storage (CCUS) is to reduce the amount of CO2 released into the atmosphere and to mitigate its effects on climate change. Over the years, naturally occurring CO2 sources have been utilized in enhanced oil recovery (EOR) projects in the United States. This has presented an opportunity to supplement and gradually replace the high demand for natural CO2 sources with anthropogenic sources. There also exist incentives for operators to become involved in the storage of anthropogenic CO2 within partially depleted reservoirs, in addition to the incremental production oil revenues. These incentives include a wider availability of anthropogenic sources, the reduction of emissions to meet regulatory requirements, tax incentives in some jurisdictions, and favorable public relations. The United States Department of Energy has sponsored several Regional Carbon Sequestration Partnerships (RCSPs) through its Carbon Storage program which have conducted field demonstrations for both EOR and saline aquifer storage. Various research efforts have been made in the area of reservoir characterization, monitoring, verification and accounting, simulation, and risk assessment to ascertain long-term storage potential within the subject storage complex. This book is a collection of lessons learned through the RCSP program within the Southwest Region of the United States. The scope of the book includes site characterization, storage modeling, monitoring verification reporting (MRV), risk assessment and international case studies

Shape classification: towards a mathematical description of the face

Recent advances in biostereometric techniques have led to the quick and easy acquisition of 3D data for facial and other biological surfaces. This has led facial surgeons to express dissatisfaction with landmark-based methods for analysing the shape of the face which use only a small part of the data available, and to seek a method for analysing the face which maximizes the use of this extensive data set. Scientists working in the field of computer vision have developed a variety of methods for the analysis and description of 2D and 3D shape. These methods are reviewed and an approach, based on differential geometry, is selected for the description of facial shape. For each data point, the Gaussian and mean curvatures of the surface are calculated. The performance of three algorithms for computing these curvatures are evaluated for mathematically generated standard 3D objects and for 3D data obtained from an optical surface scanner. Using the signs of these curvatures, the face is classified into eight 'fundamental surface types' - each of which has an intuitive perceptual meaning. The robustness of the resulting surface type description to errors in the data is determined together with its repeatability. Three methods for comparing two surface type descriptions are presented and illustrated for average male and average female faces. Thus a quantitative description of facial change, or differences between individual's faces, is achieved. The possible application of artificial intelligence techniques to automate this comparison is discussed. The sensitivity of the description to global and local changes to the data, made by mathematical functions, is investigated. Examples are given of the application of this method for describing facial changes made by facial reconstructive surgery and implications for defining a basis for facial aesthetics using shape are discussed. It is also applied to investigate the role played by the shape of the surface in facial recognition

Injury and Skeletal Biomechanics

This book covers many aspects of Injury and Skeletal Biomechanics. As the title represents, the aspects of force, motion, kinetics, kinematics, deformation, stress and strain are examined in a range of topics such as human muscles and skeleton, gait, injury and risk assessment under given situations. Topics range from image processing to articular cartilage biomechanical behavior, gait behavior under different scenarios, and training, to musculoskeletal and injury biomechanics modeling and risk assessment to motion preservation. This book, together with "Human Musculoskeletal Biomechanics", is available for free download to students and instructors who may find it suitable to develop new graduate level courses and undergraduate teaching in biomechanics