Behavioral, computational, and neuroimaging studies of acquired apraxia of speech

A critical examination of speech motor control depends on an in-depth understanding of network connectivity associated with Brodmann areas 44 and 45 and surrounding cortices. Damage to these areas has been associated with two conditions-the speech motor programming disorder apraxia of speech (AOS) and the linguistic/grammatical disorder of Broca's aphasia. Here we focus on AOS, which is most commonly associated with damage to posterior Broca's area (BA) and adjacent cortex. We provide an overview of our own studies into the nature of AOS, including behavioral and neuroimaging methods, to explore components of the speech motor network that are associated with normal and disordered speech motor programming in AOS. Behavioral, neuroimaging, and computational modeling studies are indicating that AOS is associated with impairment in learning feedforward models and/or implementing feedback mechanisms and with the functional contribution of BA6. While functional connectivity methods are not yet routinely applied to the study of AOS, we highlight the need for focusing on the functional impact of localized lesions throughout the speech network, as well as larger scale comparative studies to distinguish the unique behavioral and neurological signature of AOS. By coupling these methods with neural network models, we have a powerful set of tools to improve our understanding of the neural mechanisms that underlie AOS, and speech production generally

Fault-tolerance in cyber-physical systems: literature review and challenges

Modern industry demands techniques that ensure the operability of its processes, and even though the exponential technological advance in the last two decades in the manufacturing field, failures, waste, and unexpected interruptions are still present in this sector’s daily routine. Within the Industry 4.0 context, fault-tolerant (FT) production systems remain a complex issue and sometimes represent a vulnerable aspect. Faulttolerance techniques dedicated to autonomous and distributed systems, in a cyber-physical system (CPS) perspective, need to be investigated to follow the evolutionary pace of the manufacturing scenarios. This paper overviews these concepts and analyses the current situation in developing FT for CPS systems through a systematic literature review. The paper also discusses the research challenges in this new kind of FT systems due to new distributed architectures and emerging technologies, matching the several fault-tolerance phases.This work has been supported by FCT - Fundação para a Ciência e Tecnologia within the Project Scope: UIDB/05757/2020. This work has been partially supported by the European Regional Development Fund (ERDF) through the Interreg Spain-Portugal V-A Program (POCTEP) under grant 0677 DISRUPTIVE 2 E (Intensifying the activity of Digital Innovation Hubs within the PocTep region to boost the development of disruptive and last generation ICTs through cross-border cooperation).info:eu-repo/semantics/publishedVersio

On the use of the digital twin concept for the structural integrity protection of architectural heritage

Undoubtedly, heritage buildings serve as essential embodiments of the cultural richness and diversity of the world’s states, and their conservation is of the utmost importance. Specifically, the protection of the structural integrity of these buildings is highly relevant not only because of the buildings themselves but also because they often contain precious artworks, such as sculptures, paintings, and frescoes. When a disaster causes damage to heritage buildings, these artworks will likely be damaged, resulting in the loss of historical and artistic materials and an intangible loss of memory and identity for people. To preserve heritage buildings, state-of-the-art recommendations inspired by the Venice Charter of 1964 suggest real-time monitoring of the progressive damage of existing structures, avoiding massive interventions, and providing immediate action in the case of a disaster. The most up-to-date digital information and analysis technologies, such as digital twins, can be employed to fulfil this approach. The implementation of the digital twin paradigm can be crucial in developing a preventive approach for built cultural heritage conservation, considering its key features of continuous data exchange with the physical system and predictive analysis. This paper presents a comprehensive overview of the digital twin concept in the architecture, engineering, construction, and operation (AECO) domain. It also critically discusses some applications within the context of preserving the structural integrity of architectural heritage, with a particular emphasis on masonry structures. Finally, a prototype of the digital twin paradigm for the preservation of heritage buildings’ structural integrity is proposed.This research was supported by the doctoral grant PRT/BD/152822/2021 financed by the Portuguese Foundation for Science and Technology (FCT), under the MIT Portugal Program

Simulating and modelling the impact of secure communication latency for closed loop control

Closed loop control systems have been implemented to conduct a variety of tasks (e.g. manufacturing and automation). Industrial Control System (ICS) have been used to regulate a closed loop process; however, ICS are exposed to the same security vulnerabilities associated with enterprise networks. Cryptography has been deployed to overcome the associated data communication weaknesses between each ICS node through the use of block ciphers; however, the drawback of applying cryptographic algorithms to ICS is the additional communication latency. This paper investigates the relationship between security constructs and latency for closed loop control system with test conducted in a simulated environment. A case scenario is illustrated to demonstrate the impact of the results obtained to a real world context

Improving operational effectiveness of Tactical Long Endurance Unmanned Aerial Systems (TALEUAS) by utilizing solar power

This thesis develops, implements, and validates a hybrid energy-harvesting technique that enables extracting energy from the environment by utilizing convective thermals as a source of potential energy, and exploiting solar radiation for photovoltaic (PV) energy to achieve long endurance flight of an autonomous glider. The dynamic behavior of convective thermals, as well as their mathematical models, are studied to determine their motion, while the navigation task is simultaneously solved using a Bayesian search approach that is based on the prior knowledge of the 3D elevation. This study advances an existing technique for detection of thermals by implementing the online identification of the airplane sink rate polar. The glider’s climb rate is optimized by implementing a modified thermalling controller, and its performance is compared to an existing method of centering in thermals. The integration of the energy extracted from the solar radiation is accomplished by the design of an Electrical Energy Management System (EEMS) that safely collects and distributes the energy onboard. The electrical energy is supplied by the semi-rigid mono crystalline silicon solar cells, which are embedded into the skin of the glider’s wings without distorting the airfoil. To validate and verify the algorithms developed in MATLAB/Simulink, an interface to a high-fidelity pilot’s training flight simulator was designed. Furthermore, the numerical algorithms were integrated onboard a prototype SB-XC glider equipped with solar cells to enable the desired energy-harvesting technique. Flight test results verify the feasibility of the developed algorithms.Outstanding ThesisLieutenant, Mexican NavyApproved for public release; distribution is unlimited

On the use of a reflective architecture to augment Database Management Systems

The Database Management System (DBMS) used to be a commodity software component, with well known standard interfaces and semantics. However, the performance and reliability expectations being placed on DBMSs have increased the demand for a variety add-ons, that augment the functionality of the database in a wide range of deployment scenarios, offering support for features such as clustering, replication, and selfmanagement, among others. The effectiveness of such extensions largely rests on closely matching the actual needs of applications, hence on a wide range of tradeoffs and configuration options out of the scope of traditional client interfaces. A well known software engineering approach to systems with such requirements is reflection. Unfortunately, standard reflective interfaces in DBMSs are very limited (for instance, they often do not support the desired range of atomicity guarantees in a distributed setting). Some of these limitations may be circumvented by implementing reflective features as a wrapper to the DBMS server. Unfortunately, this solutions comes at the expense of a large development effort and significant performance penalty. In this paper we propose a general purpose DBMS reflection architecture and interface, that supports multiple extensions while, at the same time, admitting efficient implementations. We illustrate the usefulness of our proposal with concrete examples, and evaluate its cost and performance under different implementation strategies

Stabilizing Two-Qubit Entanglement with Dynamically Decoupled Active Feedback

We propose and analyze a protocol for stabilizing a maximally entangled state of two noninteracting qubits using active state-dependent feedback from a continuous two-qubit half-parity measurement in coordination with a concurrent, noncommuting dynamical decoupling drive. We demonstrate that such a drive can be simultaneous with the measurement and feedback, while also playing a key part in the feedback protocol itself. We show that robust stabilization with near-unit fidelity can be achieved even in the presence of realistic nonidealities, such as time delay in the feedback loop, imperfect state-tracking, inefficient measurements, dephasing from 1/f-distributed qubit-frequency noise, and relaxation. We mitigate feedback-delay error by introducing a forward-state-estimation strategy in the feedback controller that tracks the effects of control signals already in transit. More generally, the steady state is globally attractive without the need for ancillas, regardless of the error state, in contrast to most known feedback and error-correction schemes

Neurally adjusted ventilatory assist in patients with critical illness-associated polyneuromyopathy

Purpose: Diaphragmatic electrical activity (EAdi), reflecting respiratory drive, and its feedback control might be impaired in critical illness-associated polyneuromyopathy (CIPM). We aimed to evaluate whether titration and prolonged application of neurally adjusted ventilatory assist (NAVA), which delivers pressure (P aw) in proportion to EAdi, is feasible in CIPM patients. Methods: Peripheral and phrenic nerve electrophysiology studies were performed in 15 patients with clinically suspected CIPM and in 14 healthy volunteers. In patients, an adequate NAVA level (NAVAal) was titrated daily and was implemented for a maximum of 72h. Changes in tidal volume (V t) generation per unit of EAdi (V t/EAdi) were assessed daily during standardized tests of neuro-ventilatory efficiency (NVET). Results: In patients (median [range], 66 [44-80]years), peripheral electrophysiology studies confirmed CIPM. Phrenic nerve latency (PNL) was prolonged and diaphragm compound muscle action potential (CMAP) was reduced compared with healthy volunteers (p<0.05 for both). NAVAal could be titrated in all but two patients. During implementation of NAVAal for 61 (37-64)h, the EAdi amplitude was 9.0 (4.4-15.2)μV, and the V t was 6.5 (3.7-14.3)ml/kg predicted body weight. V t, respiratory rate, EAdi, PaCO2, and hemodynamic parameters remained unchanged, while PaO2/FiO2 increased from 238 (121-337) to 282 (150-440)mmHg (p=0.007) during NAVAal. V t/EAdi changed by −10 (−46; +31)% during the first NVET and by −0.1 (−26; +77)% during the last NVET (p=0.048). Conclusion: In most patients with CIPM, EAdi and its feedback control are sufficiently preserved to titrate and implement NAVA for up to 3days. Whether monitoring neuro-ventilatory efficiency helps inform the weaning process warrants further evaluatio