Passivity-Based Control of Human-Robotic Networks with Inter-Robot Communication Delays and Experimental Verification

In this paper, we present experimental studies on a cooperative control system for human-robotic networks with inter-robot communication delays. We first design a cooperative controller to be implemented on each robot so that their motion are synchronized to a reference motion desired by a human operator, and then point out that each robot motion ensures passivity. Inter-robot communication channels are then designed via so-called scattering transformation which is a technique to passify the delayed channel. The resulting robotic network is then connected with human operator based on passivity theory. In order to demonstrate the present control architecture, we build an experimental testbed consisting of multiple robots and a tablet. In particular, we analyze the effects of the communication delays on the human operator's behavior

A review of Fixed Bed Gasification Systems for Biomass

Rosana G. Moreira, Editor-in-Chief; Texas A&M UniversityThis is a paper from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 9 (2007): A review of Fixed Bed Gasification Systems for Biomass. Invited Overview. Vol. IX. April, 2007

Static dielectric response and Born effective charge of BN nanotubes from {\it ab initio} finite electric field calculations

{\it Ab initio} investigations of the full static dielectric response and Born effective charge of BN nanotubes (BN-NTs) have been performed for the first time using finite electric field method. It is found that the ionic contribution to the static dielectric response of BN-NTs is substantial and also that a pronounced chirality-dependent oscillation is superimposed on the otherwise linear relation between the longitudinal electric polarizability and the tube diameter ($D$), as for a thin dielectric cylinderical shell. In contrast, the transverse dielectric response of the BN-NTs resemble the behavior of a thin (non-ideal) conducting cylindrical shell of a diameter of $D+4$\AA$$, with a screening factor of 2 for the inner electric field. The medium principal component $Z_y^*$ of the Born effective charge corresponding to the transverse atomic displacement tangential to the BN-NT surface, has a pronounced $D$-dependence (but independent of chirality), while the large longitudinal component $Z_z^*$ exhibits a clear chirality dependence (but nearly $D$-independent), suggesting a powerful way to characterize the diameter and chirality of a BN-NT.Comment: submitted to PR

Epidemic shigella dysentery in children in northern KwaZulu-Natal

Objectives. To describe the epidemiology, clinical features, management and outcome of children with Shigella dysenteriae type I infection admitted to a rural district hospital. Design. Prospective cohort study. Setting. Hlabisa Hospital, KwaZulu-Natal. Subjects. Children aged under 12 years admitted with a history of bloody mucoid diarrhoea between February and December 1995. Main outcome measures. Number of admissions, age, sex, clinical features, complications and outcome. Results. Between February and December 1995, 158 cases of bloody diarrhoea were admitted, compared with 6 the previous year. Shigella dysenteriae type I, resistant to ampicillin, tetracycline, chloramphenicol, trimethoprim and sulphamethoxazole, but susceptible to nalidixic acid and ceftriaxone, was isolated. The mean age of patients was 30 months. Patients typically presented with frequent bloody mucoid diarrhoea, fever, abdominal pain and dehydration. One hundred and sixteen (73%) recovered, 17 (11%) were transferred for tertiary care, 4 (3%) absconded, and 21 died (case fatality rate = 13%; 95% confidence interval (CI) 8 - 20). Seventeen (11%) developed haemolytic uraemic syndrome and 4 (3%) a protein-losing enteropathy. The malnourished (adjusted relative risk (RR) 3.3, 95% CI 1.6 - 7.1; P < 0.01) and those aged less than 2 years (adjusted RR 4.2; 95% CI 1.0 - 17.2; P = 0.05) were more likely to die. Dysentery deaths accounted for 19% of total paediatric hospital mortality. Conclusion. A serious epidemic of shigella dysentery has established itself and is having a significant impact in this area. The virulence and drug resistance of the organism has resulted in high levels of morbidity and mortality Broad public health measures will be needed to contain the epidemic. Further community-based surveillance is urgently needed, as is research to determine modes and risk factors for transmission.4 page(s

An integrated approach to supply chain risk analysis

Despite the increasing attention that supply chain risk management is receiving by both researchers and practitioners, companies still lack a risk culture. Moreover, risk management approaches are either too general or require pieces of information not regularly recorded by organisations. This work develops a risk identification and analysis methodology that integrates widely adopted supply chain and risk management tools. In particular, process analysis is performed by means of the standard framework provided by the Supply Chain Operations Reference Model, the risk identification and analysis tasks are accomplished by applying the Risk Breakdown Structure and the Risk Breakdown Matrix, and the effects of risk occurrence on activities are assessed by indicators that are already measured by companies in order to monitor their performances. In such a way, the framework contributes to increase companies' awareness and communication about risk, which are essential components of the management of modern supply chains. A base case has been developed by applying the proposed approach to a hypothetical manufacturing supply chain. An in-depth validation will be carried out to improve the methodology and further demonstrate its benefits and limitations. Future research will extend the framework to include the understanding of the multiple effects of risky events on different processe

Qualitative analysis of foot intersegment coordination in the sagittal plane following surgery for end-stage ankle osteoarthrosis.

Today, ankle joint kinematic assessment gives important information regarding the intersegment range of motion. It does not, however, provide information regarding coordination between the segments. This study aimed to determine whether or not intersegment coordination can provide valuable, otherwise missed information in relation to kinematic alterations of the ankle joint. The study consisted of 40 participants, including 12 total ankle replacement (TAR) patients, 12 ankle arthrodesis (AA) patients, and 16 controls. Gait assessment was carried out wearing 3-D inertial sensors. Intersegment coordination was determined by calculation of the continuous relative phase (CRP) between foot intersegments. CRP analysis found useful information regarding the magnitude and directionality of segment motion throughout the gait cycle, with AA patients reporting an altered coordination pattern for all three intersegments, forefoot-hindfoot, hindfoot-shank, and forefoot-shank, and TAR patients showing alterations in the hindfoot-shank intersegment. Results show that assessment of intersegment coordination can provide further information, otherwise overlooked by the general kinematic assessment, which could be used to optimize patient rehabilitation. Furthermore, the study showed that such information could be used to compare surgical outcomes. As a result, the study concludes that the inclusion of intersegment coordination assessment could be beneficial in clinical practice. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1304-1310, 2017

Diagnostic accuracy of chromohysteroscopy in women with unexplained infertility

Background: Chronic endometritis has been related to infertility but it is usually asymptomatic and the diagnosis is rarely suspected clinically. In cases of absence of any macroscopic abnormalities during conventional hysteroscopy, endometrial dyeing using methylene blue help identify abnormal areas and coupled with the histopathological examination gives a better diagnosis of endometritis.Methods: This study was conducted on 100 infertile women in Department of Obstetrics and Gynecology at Lady Hardinge Medical College, New Delhi over a period of one year. All women under- went hysteroscopy followed by chromohysteroscopy using 1% methylene blue dye. Biopsy was taken from light and dark stained areas. The histopathology results of these samples were compared and analyzed in relation with hysteroscopic and chromohysteroscopic findings and diagnostic accuracy calculated.Results: Out of 100 women who underwent dianostic hysteroscopy 68 cases had normal findings and 32 had abnormal finding and on chromohysteroscopy light staining pattern was seen in 56 cases and 44 cases had dark staining. Histopathology of biopsy tissue from these dark stained areas showed endometritis in 50% (22 out of 44 cases) and normal endometrium in 50% (22 out of 44) cases, and biopsy from light stained area showed chronic endometritis in 5.35% (3 out of 56) cases and remaining 94.65% had normal endometrium. Diagnostic accuracy of chromohysteroscopy were sensitivity=88%, specificity=70.66%, PPV=50%, NPV=94.6%.Conclusions: Chromohysteroscopy is a simple and effective technique for diagnosing endometrial pathology in cases of infertility