A laser based semi-autonomous wheelchair using Bayesian theory

University of Technology, Sydney. Faculty of Engineering and Information Technology.Reports show that the number of elderly people and people with disabilities in society are significantly increasing. These people have a wide range and variety of functional impairments. The aim of rehabilitation technology is to improve the quality of life of people with disabilities. In particular, smart wheelchairs have been developed to accommodate people with mobility impairments. The provision of independent mobility can produce substantial benefits, such as the development of physical, cognitive, communication and social skills for both children and adults in their daily lives. In this thesis, we present a method of constructing a 360° real-time environmental map for the smart wheelchair. It combines the information from a laser range finder and encoders mounted in the driving wheels. As the wheelchair moves, the obstacles in front of the wheelchair that are detected by the laser sensor are updated to this map, after a modification based on the encoder data. This mapping method is 13-fold more accurate than the common use of encoders. Also, a method of determining accessible free-space for the obstacle avoidance task is implemented. This accommodates the actual dimensions of the wheelchair and then determines the collision-free area available for the wheelchair. The data of accessible free-space can be used to simplify the obstacle avoidance controller and improve its real-time capabilities. It eliminates errors from the common approximation of the wheelchair boundary as a circle, which may lead to the assumption that no accessible space is available to move safely without incurring a collision. We introduce an advanced obstacle avoidance technique that utilises separate Bayesian neural networks for specified tasks. The obstacle avoidance task is divided into three sub-tasks: passing through a door, corridor and wall following, and general obstacle avoidance. This enables the network to respond to the particular features of each task, thereby improving performance. Specific data acquisitions are performed to collect the patterns used to design the neural network for each task. Bayesian framework is then applied to determine the optimal network structures. The training patterns are subsequently used in conjunction with the Bayesian training process to improve the generalisation and performances of each network. Our method was able to successfully accomplish difficult navigation tasks smoothly following a near optimum trajectory. Furthermore, we developed an adaptive shared control method for an intelligent wheelchair based on the Bayesian recursive technique to assist disabled users when performing obstacle avoidance tasks. Three autonomous tasks have been developed for different types of environments to improve the performance of the overall system. The system combines local environmental information gathered using a laser range finder sensor with the user's intentions to select the most suitable autonomous task in different situation. The evidences of these tasks are estimated by the Bayesian recursive technique during movements of the wheelchair. The most appropriate task that is selected automatically by the wheelchair controller is the one that has the highest value of evidence. Finally, a method of classifying the environmental model is introduced for this shared control strategy. The features of the environment such as doorways, corridors and walls, and general obstacles have to be recognised. This method is based on the Bayesian neural network to recognise the environmental features from the laser images that were acquired from the on board sensors. This environmental feature information is one of the main inputs of the adaptive shared control strategy to effectively improve the accuracy of autonomous task selection. Various experiments are conducted to evaluate the performance of our smart wheelchair system. Eight able-bodied people are recruited, including four males and four females whose ages range from 27 years to 60 years. They have had no experience of driving a wheelchair before. Three experiments are arranged with increasing difficulties. These users are asked to drive the wheelchair in both manual mode via a conventional joystick and in semi-autonomous mode with the shared control strategy and autonomous obstacle avoidance controller. The evaluation results show the advantages of our wheelchair's control system compared to the manual control method. Our intelligent wheelchair, which was equipped with a reliable obstacle avoidance method and an effective shared control strategy, was able to successfully accomplish difficult navigation tasks not only by following a near optimum trajectory but also by generating smooth movements (maintaining stable velocities) in different types of environments. It is able to successfully support people with various types and levels of impairment

Massive Parallel Quantum Computer Simulator

We describe portable software to simulate universal quantum computers on massive parallel computers. We illustrate the use of the simulation software by running various quantum algorithms on different computer architectures, such as a IBM BlueGene/L, a IBM Regatta p690+, a Hitachi SR11000/J1, a Cray X1E, a SGI Altix 3700 and clusters of PCs running Windows XP. We study the performance of the software by simulating quantum computers containing up to 36 qubits, using up to 4096 processors and up to 1 TB of memory. Our results demonstrate that the simulator exhibits nearly ideal scaling as a function of the number of processors and suggest that the simulation software described in this paper may also serve as benchmark for testing high-end parallel computers.Comment: To appear in Comp. Phys. Com

Genome-wide essential gene identification in Streptococcus sanguinis

A clear perception of gene essentiality in bacterial pathogens is pivotal for identifying drug targets to combat emergence of new pathogens and antibiotic-resistant bacteria, for synthetic biology, and for understanding the origins of life. We have constructed a comprehensive set of deletion mutants and systematically identified a clearly defined set of essential genes for Streptococcus sanguinis. Our results were confirmed by growing S. sanguinis in minimal medium and by double-knockout of paralogous or isozyme genes. Careful examination revealed that these essential genes were associated with only three basic categories of biological functions: maintenance of the cell envelope, energy production, and processing of genetic information. Our finding was subsequently validated in two other pathogenic streptococcal species, Streptococcus pneumoniae and Streptococcus mutans and in two other gram-positive pathogens, Bacillus subtilis and Staphylococcus aureus. Our analysis has thus led to a simplified model that permits reliable prediction of gene essentiality

Meta-analysis identifies novel risk loci and yields systematic insights into the biology of male-pattern baldness

Life & Brain GmbH; the BONFOR programme of the University of Bonn; and the Agency for Science, Technology and Research (A*STAR). M.M.N. is a member of the DFG Excellence Cluster ImmunoSensation

Genetic prediction of male pattern baldness

Male pattern baldness can have substantial psychosocial effects, and it has been phenotypically linked to adverse health outcomes such as prostate cancer and cardiovascular disease. We explored the genetic architecture of the trait using data from over 52,000 male participants of UK Biobank, aged 40-69 years. We identified over 250 independent genetic loci associated with severe hair loss (P<5x10-8). By splitting the cohort into a discovery sample of 40,000 and target sample of 12,000, we developed a prediction algorithm based entirely on common genetic variants that discriminated (AUC = 0.78, sensitivity = 0.74, specificity = 0.69, PPV = 59%, NPV = 82%) those with no hair loss from those with severe hair loss. The results of this study might help identify those at greatest risk of hair loss, and also potential genetic targets for intervention

Endothelial Nitric Oxide Pathways in the Pathophysiology of Dengue: A Prospective Observational Study

Background: Dengue can cause increased vascular permeability that may lead to hypovolemic shock. Endothelial dysfunction may underlie this; however, the association of endothelial nitric oxide (NO) pathways with disease severity is unknown. Methods: We performed a prospective observational study in 2 Vietnamese hospitals, assessing patients presenting early (<72 hours of fever) and patients hospitalized with warning signs or severe dengue. The reactive hyperemic index (RHI), which measures endothelium-dependent vasodilation and is a surrogate marker of endothelial function and NO bioavailability, was evaluated using peripheral artery tonometry (EndoPAT), and plasma levels of l-arginine, arginase-1, and asymmetric dimethylarginine were measured at serial time-points. The main outcome of interest was plasma leakage severity. Results: Three hundred fourteen patients were enrolled; median age of the participants was 21(interquartile range, 13-30) years. No difference was found in the endothelial parameters between dengue and other febrile illness. Considering dengue patients, the RHI was significantly lower for patients with severe plasma leakage compared to those with no leakage (1.46 vs 2.00; P < .001), over acute time-points, apparent already in the early febrile phase (1.29 vs 1.75; P = .012). RHI correlated negatively with arginase-1 and positively with l-arginine (P = .001). Conclusions: Endothelial dysfunction/NO bioavailability is associated with worse plasma leakage, occurs early in dengue illness and correlates with hypoargininemia and high arginase-1 levels

Long-term humoral immune response in persons with asymptomatic or mild SARS-CoV-2 infection, Vietnam

Antibody response against nucleocapsid and spike proteins of SARS-CoV-2 in 11 persons with mild or asymptomatic infection rapidly increased after infection. At weeks 18–30 after diagnosis, all remained seropositive but spike protein–targeting antibody titers declined. These data may be useful for vaccine development

The energy expenditure at critically ill patients

The aim of this study was to determine energy expenditure and to find relations between resting energy expenditure (REE) and selected parameters in 14 polytraumatic patients in the ICU of University Hospital in Hradec Kralove, which were easily measurable and usable for REE prediction. In this study 7 men (age 36 ± 18 years) and 7 women (age 58 ± 28 years) with polytrauma were examined. The assessment of REE was measured via indirect calorimetry (IC) method. The examination also included bioimpedance analysis (BIA). BIA was useful especially for obtaining values of overhydration (OH), lean tissue mass (LTM) and metabolically active body cell mass (BCM). Average REE-IC (measured by IC) was 2116 ± 516 kcal·day-1 in men and 1450 ± 407 kcal·day-1 in women (P = 0.018). Statistically significant difference between men's and women's population was also found in these relations: calculation of basal energy expenditure according to Harris-Bennedict equation without (P = 0.001) and with deduction of OH from body weight (P = 0.001), at "breathing energy expenditure" (REE related to respiratory rate) (P = 0.018) and at (REE related to heart rate) "heart rate energy expenditure" (P = 0.038). REE-IC related to kilogram of BCM with and without deduction of overhydration was shown as statistically significant..

Intravenous magnesium sulfate for the management of severe hand, foot, and mouth disease with autonomic nervous system dysregulation in Vietnamese children: study protocol for a randomized controlled trial

Over the last 15 years, hand, foot, and mouth disease (HFMD) has emerged as a major public health burden across the Asia-Pacific region. A small proportion of HFMD patients, typically those infected with enterovirus 71 (EV71), develop brainstem encephalitis with autonomic nervous system (ANS) dysregulation and may progress rapidly to cardiopulmonary failure and death. Although milrinone has been reported to control hypertension and support myocardial function in two small studies, in practice, a number of children still deteriorate despite this treatment. Magnesium sulfate (MgSO4) is a cheap, safe, and readily available medication that is effective in managing tetanus-associated ANS dysregulation and has shown promise when used empirically in EV71-confirmed severe HFMD cases.We describe the protocol for a randomized, placebo-controlled, double-blind trial of intravenous MgSO4 in Vietnamese children diagnosed clinically with HFMD plus ANS dysregulation with systemic hypertension. A loading dose of MgSO4 or identical placebo is given over 20 min followed by a maintenance infusion for 72 h according to response, aiming for Mg levels two to three times the normal level in the treatment arm. The primary endpoint is a composite of disease progression within 72 h defined as follows: development of pre-specified blood pressure criteria necessitating the addition of milrinone, the need for ventilation, shock, or death. Secondary endpoints comprise these parameters singly, plus other clinical endpoints including the following: requirement for other inotropic agents; duration of hospitalization; presence of neurological sequelae at discharge in survivors; and neurodevelopmental status assessed 6 months after discharge. The number and severity of adverse events observed in the two treatment arms will also be compared. Based on preliminary data from a case series, and allowing for some losses, 190 patients (95 in each arm) will allow detection of a 50 % reduction in disease progression with 90 % power at a two-sided 5 % significance level.Given the large numbers of HFMD cases currently being seen in hospitals in Asia, if MgSO4 is shown to be effective in controlling ANS dysregulation and preventing severe HFMD complications, this finding would be important to pediatric care throughout the region.ClinicalTrials.gov Identifier: NCT01940250 (Registered 22 August 2013)