252 research outputs found

    Indoor Localization of Mobile Robots with Wireless Sensor Network Based on Ultra Wideband using Experimental Measurements of Time Difference of Arrival

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    This paper presents investigations into wireless localization techniques for mobile robots operating in indoor environments. Localization systems can guide robots to perform different tasks such as monitoring children or elderly people, aid mobility of the visually impaired and localize mobile objects or packages in warehouses. They are essential for localization of robots operating in re-mote places that are inaccessible or hazardous to humans. Currently, ultra wide band (UWB) in indoor environments provides an accuracy of 24 mm under line of sight (LOS) or non-line of sight (NLOS) conditions in a working range of 160 m indoors. The work presented in this paper carries out experimental validation of localization algorithms using mobile robots and UWB signals. These are measured in LOS and NLOS environments. The measurements are performed with the UWB radio PulsON 410 (P410) and mobile robots (AmigoBot) with maximum travel-ling speed of 1 m/s and equipped with an on-board computer, sonar, odometer, camera and inertial navigation system. Experimental results obtained for the system show positioning errors of less than 55 mm

    Comparison of MUSIC and ESPRIT DOA Estimation algorithms for Wireless Communications

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    This paper presents simulation of Angle of Arrival (AOA) estimation using the Multiple Signal Classification (MUSIC) and Estimation of Signal Parameters via Rotational Invariance Technique (ESPRIT) algorithms. We study the localization techniques using the wireless communication systems and there are several algorithms that have the ability in calculate the Direction of Arrival (DOA) of the incident signals. We investigate and compare MUSIC and ESPRIT algorithms. The simulations indicate that the MUSIC algorithm is more accurate and stable compared to the ESPRIT algorithm

    Qualitative study to develop processes and tools for the assessment and tracking of African institutions’ capacity for operational health research

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    Objectives Research is key to achieving global development goals. Our objectives were to develop and test an evidence-informed process for assessing health research management and support systems (RMSS) in four African universities and for tracking interventions to address capacity gaps. Setting Four African universities. Participants 83 university staff and students from 11 cadres. Intervention/methods A literature-informed ‘benchmark’ was developed and used to itemise all components of a university’s health RMSS. Data on all components were collected during site visits to four African universities using interview guides, document reviews and facilities observation guides. Gaps in RMSS capacity were identified against the benchmark and institutional action plans developed to remedy gaps. Progress against indicators was tracked over 15 months and common challenges and successes identified. Results Common gaps in operational health research capacity included no accessible research strategy, a lack of research e-tracking capability and inadequate quality checks for proposal submissions and contracts. Feedback indicated that the capacity assessment was comprehensive and generated practical actions, several of which were no-cost. Regular follow-up helped to maintain focus on activities to strengthen health research capacity in the face of challenges. Conclusions Identification of each institutions’ strengths and weaknesses against an evidence-informed benchmark enabled them to identify gaps in in their operational health research systems, to develop prioritised action plans, to justify resource requests to fulfil the plans and to track progress in strengthening RMSS. Use of a standard benchmark, approach and tools enabled comparisons across institutions which has accelerated production of evidence about the science of research capacity strengthening. The tools could be used by institutions seeking to understand their strengths and to address gaps in research capacity. Research capacity gaps that were common to several institutions could be a ‘smart’ investment for governments and health research funders

    Educational Bandwidth Traffic Prediction using Non-Linear Autoregressive Neural Networks

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    Time series network traffic analysis and forecasting are important for fundamental to many decision-making processes, also to understand network performance, reliability and security, as well as to identify potential problems. This paper provides the latest work at London South Bank University (LSBU) network data traffic analysis by adapting nonlinear autoregressive exogenous model (NARX) based on the Levenberg-Marquardt backpropagation algorithm. This technique can analyze and predict data usage in its current and future states, as well as visualise the hourly, daily, weekly, monthly, and quarterly activities with less computation requirement. Results and analysis proved the accuracy of the prediction techniques

    Qualitative study to develop processes and tools for the assessment and tracking of African institutions’ capacity for operational health research

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    Objectives Research is key to achieving global development goals. Our objectives were to develop and test an evidence-informed process for assessing health research management and support systems (RMSS) in four African universities and for tracking interventions to address capacity gaps. Setting Four African universities. Participants 83 university staff and students from 11 cadres. Intervention/methods A literature-informed ‘benchmark’ was developed and used to itemise all components of a university’s health RMSS. Data on all components were collected during site visits to four African universities using interview guides, document reviews and facilities observation guides. Gaps in RMSS capacity were identified against the benchmark and institutional action plans developed to remedy gaps. Progress against indicators was tracked over 15 months and common challenges and successes identified. Results Common gaps in operational health research capacity included no accessible research strategy, a lack of research e-tracking capability and inadequate quality checks for proposal submissions and contracts. Feedback indicated that the capacity assessment was comprehensive and generated practical actions, several of which were no-cost. Regular follow-up helped to maintain focus on activities to strengthen health research capacity in the face of challenges. Conclusions Identification of each institutions’ strengths and weaknesses against an evidence-informed benchmark enabled them to identify gaps in in their operational health research systems, to develop prioritised action plans, to justify resource requests to fulfil the plans and to track progress in strengthening RMSS. Use of a standard benchmark, approach and tools enabled comparisons across institutions which has accelerated production of evidence about the science of research capacity strengthening. The tools could be used by institutions seeking to understand their strengths and to address gaps in research capacity. Research capacity gaps that were common to several institutions could be a ‘smart’ investment for governments and health research funders

    Changes in the Transmission Dynamic of Chikungunya Virus in Southeastern Senegal.

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    In Senegal, chikungunya virus (CHIKV) is maintained in a sylvatic cycle and causes sporadic cases or small outbreaks in rural areas. However, little is known about the influence of the environment on its transmission. To address the question, 120 villages were randomly selected in the Kedougou region of southeastern Senegal. In each selected village, 10 persons by randomly selected household were sampled and tested for specific anti-CHIKV IgG antibodies by ELISA. We investigated the association of CHIKV seroprevalence with environmental variables using logistic regression analysis and the spatial correlation of village seroprevalence based on semivariogram analysis. Fifty-four percent (51%-57%) of individuals sampled during the survey tested positive for CHIKV-specific IgG. CHIKV seroprevalence was significantly higher in populations living close to forested areas (Normalized Difference Vegetation Index (NDVI), Odds Ratio (OR) = 1.90 (1.42-2.57)), and was negatively associated with population density (OR = 0.76 (0.69-0.84)). In contrast, in gold mining sites where population density was >400 people per km2, seroprevalence peaked significantly among adults (46% (27%-67%)) compared to all other individuals (20% (12%-31%)). However, traditional gold mining activities significantly modify the transmission dynamic of CHIKV, leading to a potential increase of the risk of human exposition in the region

    African baobabs with a very large number of stems and false stems : radiocarbon Investigation of the baobab of Warang

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    Author Posting. © Studia Chemia, 2017. This article is posted here by permission of Studia Chemia for personal use, not for redistribution. The definitive version was published in Studia Universitatis Babes-Bolyai, Seria Chemia 62, no. 1 (2017): 111-120, doi:10.24193/subbchem.2017.1.09.The article presents the AMS (accelerator mass spectrometry) radiocarbon dating results of the baobab of Warang, Senegal. The investigation of the baobab revealed that it consists of 18 partially fused stems, which represents the largest number of stems reported for an African baobab. Three stems build the ring that closes a false cavity, while 15 stems grow outside the ring. Seven wood samples were collected from the false cavity and from the outer part of other stems. The dating results evinced that the stems belong to four different generations, out of which the first generation is around 500 years old. We also documented the presence of false stems, which emerge from a large adjacent stem, are triangular in horizontal section and act as an anchor. The baobab of Warang possesses 12 ordinary stems and 6 false stems.The research was funded by the Romanian Ministry of National Education CNCS-UEFISCDI under grant PN-II-ID-PCE-2013-76

    Development of mobile laboratory for viral hemorrhagic fever detection in Africa

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    Background In order to enable local response to viral haemorrhagic fever outbreaks a mobile laboratory transportable on commercial flights was developed. Methodology The development progressed from use of mobile real time RT-PCR to mobile Recombinase Polymerase Amplification (RT-RPA). The various stages of the mobile laboratory development are described. Results A brief overview of its deployments, which culminated in the first on site detection of Ebola virus disease (EVD) in March 2014 and a successful use in a campaign to roll back EVD cases in Conakry in the West-Africa Ebola virus outbreak are described. Conclusion The developed mobile laboratory successfully enabled local teams to perform rapid viral haemorrhagic fever disgnostics

    The association between malaria parasitaemia, erythrocyte polymorphisms, malnutrition and anaemia in children less than 10 years in Senegal:a case control study

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    BACKGROUND: Malaria and anaemia (Haemoglobin <11 g/dl) remain frequent in tropical regions and are closely associated. Although anaemia aetiologies are known to be multi-factorial, most studies in malaria endemic areas have been confined to analysis of possible associations between anaemia and individual factors such as malaria. A case control study involving children aged from 1 to 10 years was conducted to assess some assumed contributors to anaemia in the area of Bonconto Health post in Senegal. METHODS: Study participants were randomly selected from a list of children who participated in a survey in December 2010. Children aged from 1 to 10 years with haemoglobin level below 11 g/dl represented cases (anaemic children). Control participants were eligible if of same age group and their haemoglobin level was >= 11 g/dl. For each participant, a physical examination was done and anthropometric data collected prior to a biological assessment which included: malaria parasitaemia infection, intestinal worm carriage, G6PD deficiency, sickle cell disorders, and alpha-talassaemia. RESULTS: Three hundred and fifty two children < 10 years of age were enrolled (176 case and 176 controls). In a logistic regression analysis, anaemia was significantly associated with malaria parasitaemia (aOR=5.23, 95%CI[1.1-28.48]), sickle cell disorders (aOR=2.89, 95%CI[1,32-6.34]), alpha-thalassemia (aOR=1.82, 95%CI[1.2-3.35]), stunting (aOR=3.37, 95%CI[1.93-5.88], age ranged from 2 to 4 years (aOR=0.13, 95%CI[0.05-0.31]) and age > 5 years (aOR=0.03, 95%CI[0.01-0.08]). Stratified by age group, anaemia was significantly associated with stunting in children less than 5 years (aOR=3.1 95%CI[1.4 – 6.8]), with, sickle cell disorders (aOR=3.5 95%CI [1.4 – 9.0]), alpha-thalassemia (or=2.4 95%CI[1.1–5.3]) and stunting (aOR=3.6 95%CI [1.6–8.2]) for children above 5 years. No association was found between G6PD deficiency, intestinal worm carriage and children’s gender. CONCLUSION: Malaria parasitaemia, stunting and haemoglobin genetic disorders represented the major causes of anaemia among study participants. Anaemia control in this area could be achieved by developing integrated interventions targeting both malaria and malnutrition
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