Design and Implementation of Welding Mobile Robot Using a Proposed Control Scheme Based On Its Developed Dynamic Modeling for Tracking Desired Welding Trajectory

This paper presents a proposed control scheme that makes the combination of a kinematic controller (KC) and an integral sliding mode controller (ISMC) for a welding mobile robot (WMR) to track a desired welding path. First, a posture tracking error vector is defined and a kinematic controller is designed based on kinematic modeling to make the tracking error vector go to zero asymptotically. Second, a sliding surface vector is defined based on the velocity tracking error vector and its integral term. And then, an integral sliding mode dynamic controller is designed based on developed dynamic modeling to make velocity tracking error vector also go to zero asymptotically. The above controllers are obtained by backstepping method. The stability of system is proved based on the Lyapunov stability theory. To implement the designed tracking controller, a control system is developed based on DSP F28355 and ATmega328. A scheme for measuring the posture tracking error vector using torch sensor is presented. The simulation and experiment results are shown to illustrate effectiveness and the applicability to the welding industry field of the proposed controller

Land-use dynamics in the Mekong delta: From national policy to livelihood sustainability

The Vietnamese Mekong Delta (VMD) is one of the most examined deltas in the world given its dynamics, complexity, and vulnerability. In the past decades, the VMD has changed rapidly, especially the land use in relation with the socioeconomic development. National policy has profoundly influenced these changes and the changes have significantly affected local livelihoods. However, these changes are not well reported systematically. In this study, we investigate land-use changes based on institutional analyses across multiple scales, that is, from national, provincial, to local livelihood based on institutional and sustainability analysis. The results show a strong relationship between legal settings over the last 30 years on land use and livelihood transitions. In addition, the constraints of implementing national legal frameworks at provincial level in practice were identified including effects to local livelihoods. We offer some recommendations for sustainable livelihoods in the VMD, with a focus on increasing socioecological resilience.Most of Vietnamese authors are supported by the projects “Transforming agricultural livelihoods for climate change adaptation in the Vietnamese Mekong Delta: A case study in Ben Tre province - KHCNTNB-DT/14-19/C20”, regular funding by Vietnam National University – Ho Chi Minh City (under grant number TX2019-48-01) and “Floodbased farming systems for enhancing livelihood resilience in the floodplain of upper Mekong delta“ (DUPC2 Grant 108 474)

Evaluation of GeneXpert MTB/RIF for Diagnosis of Tuberculous Meningitis

Tuberculous meningitis (TBM) is the most severe form of tuberculosis. Microbiological confirmation is rare, and treatment is often delayed, increasing mortality and morbidity. The GeneXpert MTB/RIF test was evaluated in a large cohort of patients with suspected tuberculous meningitis. Three hundred seventy-nine patients presenting with suspected tuberculous meningitis to the Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam, between 17 April 2011 and 31 December 2012 were included in the study. Cerebrospinal fluid samples were tested by Ziehl-Neelsen smear, mycobacterial growth indicator tube (MGIT) culture, and Xpert MTB/RIF. Rifampin (RIF) resistance results by Xpert were confirmed by an MTBDR-Plus line probe assay and all positive cultures were tested by phenotypic MGIT drug susceptibility testing. Overall, 182/379 included patients (48.0%) were diagnosed with tuberculous meningitis. Sensitivities of Xpert, smear, and MGIT culture among patients diagnosed with TBM were 59.3% (108/182 [95% confidence interval {CI}, 51.8 to 66.5%]), 78.6% (143/182 [95% CI, 71.9 to 84.3%]) and 66.5% (121/182 [95% CI, 59.1 to 73.3%]), respectively. There was one false-positive Xpert MTB/RIF test (99.5% specificity). Four cases of RIF resistance (4/109; 3.7%) were identified by Xpert, of which 3 were confirmed to be multidrug-resistant (MDR) TBM and one was culture negative. Xpert MTB/RIF is a rapid and specific test for the diagnosis of tuberculous meningitis. The addition of a vortexing step to sample processing increased sensitivity for confirmed TBM by 20% (P = 0.04). Meticulous examination of a smear from a large volume of cerebrospinal fluid (CSF) remains the most sensitive technique but is not practical in most laboratories. The Xpert MTB/RIF represents a significant advance in the early diagnosis of this devastating condition

Care practices and traditional beliefs related to neonatal jaundice in northern Vietnam: a population-based, cross-sectional descriptive study

BACKGROUND: The National Hospital of Pediatrics in Vietnam performed >200 exchange transfusions annually (2006–08), often on infants presenting encephalopathic from lower-level hospitals. As factors delaying care-seeking are not known, we sought to study care practices and traditional beliefs relating to neonatal jaundice in northern Vietnam. METHODS: We conducted a prospective, cross-sectional, population-based, descriptive study from November 2008 through February 2010. We prospectively identified mothers of newborns through an on-going regional cohort study. Trained research assistants administered a 78-item questionnaire to mothers during home visits 14–28 days after birth except those we could not contact or whose babies remained hospitalized at 28 days. RESULTS: We enrolled 979 mothers; 99% delivered at a health facility. Infants were discharged at a median age of 1.35 days. Only 11% received jaundice education; only 27% thought jaundice could be harmful. During the first week, 77% of newborns were kept in dark rooms. Only 2.5% had routine follow-up before 14 days. Among 118 mothers who were worried by their infant’s jaundice but did not seek care, 40% held non-medical beliefs about its cause or used traditional therapies instead of seeking care. Phototherapy was uncommon: 6 (0.6%) were treated before discharge and 3 (0.3%) on readmission. However, there were no exchange transfusions, kernicterus cases, or deaths. CONCLUSIONS: Early discharge without follow-up, low maternal knowledge, cultural practices, and use of traditional treatments may limit or delay detection or care-seeking for jaundice. However, in spite of the high prevalence of these practices and the low frequency of treatment, no bad outcomes were seen in this study of nearly 1,000 newborns. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/1471-2431-14-264) contains supplementary material, which is available to authorized users