Hierarchical Neurocontroller Architecture for Robotic Manipulation

A hierarchical neurocontroller architecture consisting of two artificial neural network systems for the manipulation of a robotic arm is presented. The higher-level network system participates in the delineation of the robot arm workspace and coordinates transformation and the motion decision-making process. The lower-level network provides the correct sequence of control actions. A straightforward example illustrates the architecture\u27\u27s capabilities, including speed, adaptability, and computational efficienc

Intelligent Control of a Robotic Arm Using Hierarchical Neural Network Systems

Two artificial neural network systems are considered in a hierarchical fashion to plan the trajectory and control of a robotic arm. At the higher level of the hierarchy the neural system consists of four networks: a restricted Coulomb energy network to delineate the robot arm workspace; two standard backpropagation (BP) networks for coordinates transformation; and a fourth network which also uses BP and participates in the trajectory planning by cooperating with other knowledge sources. The control emulation process which is developed using a second neural system at a lower hierarchical level provides the correct sequence of control actions. An example is presented to illustrate the capabilities of the developed architectures

Fully-automated identification of imaging biomarkers for post-operative cerebellar mutism syndrome using longitudinal paediatric MRI

Post-operative cerebellar mutism syndrome (POPCMS) in children is a post- surgical complication which occurs following the resection of tumors within the brain stem and cerebellum. High resolution brain magnetic resonance (MR) images acquired at multiple time points across a patient’s treatment allow the quantification of localized changes caused by the progression of this syndrome. However, MR images are not necessarily acquired at regular intervals throughout treatment and are often not volumetric. This restricts the analysis to 2D space and causes difficulty in intra- and inter-subject comparison. To address these challenges, we have developed an automated image processing and analysis pipeline. Multi-slice 2D MR image slices are interpolated in space and time to produce a 4D volumetric MR image dataset providing a longitudinal representation of the cerebellum and brain stem at specific time points across treatment. The deformations within the brain over time are represented using a novel metric known as the Jacobian of deformations determinant. This metric, together with the changing grey-level intensity of areas within the brain over time, are analyzed using machine learning techniques in order to identify biomarkers that correspond with the development of POPCMS following tumor resection. This study makes use of a fully automated approach which is not hypothesis-driven. As a result, we were able to automatically detect six potential biomarkers that are related to the development of POPCMS following tumor resection in the posterior fossa

The use of the articulated total body model as a robot dynamics simulation tool

The Articulated Total Body (ATB) model is a computer sumulation program which was originally developed for the study of aircrew member dynamics during ejection from high-speed aircraft. This model is totally three-dimensional and is based on the rigid body dynamics of coupled systems which use Euler's equations of motion with constraint relations of the type employed in the Lagrange method. In this paper the use of the ATB model as a robot dynamics simulation tool is discussed and various simulations are demonstrated. For this purpose the ATB model has been modified to allow for the application of torques at the joints as functions of state variables of the system. Specifically, the motion of a robotic arm with six revolute articulations with joint torques prescribed as functions of angular displacement and angular velocity are demonstrated. The simulation procedures developed in this work may serve as valuable tools for analyzing robotic mechanisms, dynamic effects, joint load transmissions, feed-back control algorithms employed in the actuator control and end-effector trajectories

On the Minimum Achievable Age of Information for General Service-Time Distributions

There is a growing interest in analysing the freshness of data in networked systems. Age of Information (AoI) has emerged as a popular metric to quantify this freshness at a given destination. There has been a significant research effort in optimizing this metric in communication and networking systems under different settings. In contrast to previous works, we are interested in a fundamental question, what is the minimum achievable AoI in any single-server-single-source queuing system for a given service-time distribution? To address this question, we study a problem of optimizing AoI under service preemptions. Our main result is on the characterization of the minimum achievable average peak AoI (PAoI). We obtain this result by showing that a fixed-threshold policy is optimal in the set of all randomized-threshold causal policies. We use the characterization to provide necessary and sufficient conditions for the service-time distributions under which preemptions are beneficial

Evaluation of Wound Healing Properties of Bioactive Fractions from the Extract of Butea monosperma (Lam) Stem Bark.

The study aims to evaluate the wound healing properties of bioactive fractions from the extract of Butea monosperma (Lam) stem bark. In this study the stem bark powder was extracted with ethanol, further the ethanolic extract was fractionated with different solvents (petroleum ether, benzene, chloroform and acetone) in increasing order of polarity. Thus prepared extracts were subjected to preliminary phytochemical analysis. The wound healing activity of the ethanolic extract and the fractions isolated from the stem bark of Butea monosperma were evaluated in excision, incision and dead space wound healing models using Albino wistar rats. The wound healing activity was assessed by the breaking strength in case of incision wounds, epithelialization and wound contraction in case of excision wound and granulation tissue dry weight, breaking strength and hydroxyproline content in case of dead space wound. The ethanolic extract and the acetone fraction showed the significant wound healing activity on all three wound models. The phytochemical investigations revealed the presence of alkaloids, tannins, flavonoids, phenolic compounds and steroids. The increased rate of wound contraction and hydroxyproline content in the ethanolic extract and the acetone fraction treated animals provides a scientific base to the ethno medicinal use of Butea monosperma, which is largely attributable to the additive or synergistic effect of their constituents. Keywords: Butea monosperma, Dead space wound, Excision wound, Incision wound

Evaluation of Wound Healing Properties of Bioactive Fractions from the Extract of Butea monosperma (Lam) Stem Bark.

The study aims to evaluate the wound healing properties of bioactive fractions from the extract of Butea monosperma (Lam) stem bark. In this study the stem bark powder was extracted with ethanol, further the ethanolic extract was fractionated with different solvents (petroleum ether, benzene, chloroform and acetone) in increasing order of polarity. Thus prepared extracts were subjected to preliminary phytochemical analysis. The wound healing activity of the ethanolic extract and the fractions isolated from the stem bark of Butea monosperma were evaluated in excision, incision and dead space wound healing models using Albino wistar rats. The wound healing activity was assessed by the breaking strength in case of incision wounds, epithelialization and wound contraction in case of excision wound and granulation tissue dry weight, breaking strength and hydroxyproline content in case of dead space wound. The ethanolic extract and the acetone fraction showed the significant wound healing activity on all three wound models. The phytochemical investigations revealed the presence of alkaloids, tannins, flavonoids, phenolic compounds and steroids. The increased rate of wound contraction and hydroxyproline content in the ethanolic extract and the acetone fraction treated animals provides a scientific base to the ethno medicinal use of Butea monosperma, which is largely attributable to the additive or synergistic effect of their constituents. Keywords: Butea monosperma, Dead space wound, Excision wound, Incision wound

Planning and Control of a Robotic Manipulator Using Neural Networks

An architecture which utilizes two artificial neural systems for planning and control of a robotic arm is presented. The first neural network system participates in the trajectory planning and the motion decision-making process. The second neural network system provides the correct sequence of control actions with a high accuracy due to the utilization of an unsupervised/supervised neural network scheme. The utilization of a hybrid hierarchical/distributed organization, supervised/unsupervised learning models, and forward modeling yielded an architecture with capabilities of high level functionality

Molecular Basis and Differentiation-Associated Alterations of Anion Secretion in Human Duodenal Enteroid Monolayers

Background & Aims: Human enteroids present a novel tool to study human intestinal ion transport physiology and pathophysiology. The present study describes the contributions of Cl- and HCO3 - secretion to total cyclic adenosine monophosphate (cAMP)-stimulated electrogenic anion secretion in human duodenal enteroid monolayers and the relevant changes after differentiation. Methods: Human duodenal enteroids derived from 4 donors were grown as monolayers and differentiated by a protocol that includes the removal of Wnt3A, R-spondin1, and SB202190 for 5 days. The messenger RNA level and protein expression of selected ion transporters and carbonic anhydrase isoforms were determined by quantitative real-time polymerase chain reaction and immunoblotting, respectively. Undifferentiated and differentiated enteroid monolayers were mounted in the Ussing chamber/voltage-current clamp apparatus, using solutions that contained as well as lacked Cl- and HCO3 -/CO2, to determine the magnitude of forskolin-induced short-circuit current change and its sensitivity to specific inhibitors that target selected ion transporters and carbonic anhydrase(s). Results: Differentiation resulted in a significant reduction in the messenger RNA level and protein expression of cystic fibrosis transmembrane conductance regulator, (CFTR) Na+/K+/2Cl- co-transporter 1 (NKCC1), and potassium channel, voltage gated, subfamily E, regulatory subunit 3 (KCNE3); and, conversely, increase of down-regulated-in-adenoma (DRA), electrogenic Na+/HCO3 - co-transporter 1 (NBCe1), carbonic anhydrase 2 (CA2), and carbonic anhydrase 4 (CA4). Both undifferentiated and differentiated enteroids showed active cAMP-stimulated anion secretion that included both Cl- and HCO3 - secretion as th

Gastrointestinal Bleeding in Patients With Acute Respiratory Distress Syndrome: A National Database Analysis.

Background:The goal of our study was to determine the impact of gastrointestinal bleeding (GIB) on in-hospital outcomes among acute respiratory distress syndrome (ARDS) patients, and subsequently determine the potential risk factors for the development of GIB. Methods:ARDS patients with and without GIB were identified using the National Inpatient Sample (2002 - 2012). Linear regression analysis was used to assess impact of GIB on in-hospital mortality, length of stay and total charges. Univariate logistic regression was used to determine associated odds ratios (OR) for causes of ARDS and common comorbid conditions. Results:We identified 149,190 ARDS patients. The incidence of GIB was the highest among patients \u3e 60 years (P \u3c 0.001). GIB was associated with longer hospitalization days (7.3 days versus 11.9 days, P \u3c 0.001), higher mortality (11% versus 27%, P \u3c 0.001) and greater economic burden ($82,812 versus$45,951, P \u3c 0.001). GIB was common in cirrhosis (OR: 8.3), peptic ulcer disease (OR: 3.7), coagulopathy disorders (OR: 3.003), thrombocytopenia (OR: 2.6), anemia (OR: 2.5) and atrial fibrillation (OR: 1.5). ARDS secondary to aspiration pneumonia (OR: 2.0), pancreatitis (OR: 2.0), sepsis (OR: 1.6) and community acquired pneumonia (OR: 0.8) was more likely to have GIB. Conclusion:Our study demonstrates that GIB in ARDS patients is associated with significant increased mortality, hospitalization and health care cost