Evolutionary strategies in swarm robotics controllers

Nowadays, Unmanned Vehicles (UV) are widespread around the world. Most of these vehicles require a great level of human control, and mission success is reliant on this dependency. Therefore, it is important to use machine learning techniques that will train the robotic controllers to automate the control, making the process more efficient. Evolutionary strategies may be the key to having robust and adaptive learning in robotic systems. Many studies involving UV systems and evolutionary strategies have been conducted in the last years, however, there are still research gaps that need to be addressed, such as the reality gap. The reality gap occurs when controllers trained in simulated environments fail to be transferred to real robots. This work proposes an approach for solving robotic tasks using realistic simulation and using evolutionary strategies to train controllers. The chosen setup is easily scalable for multirobot systems or swarm robots. In this thesis, the simulation architecture and setup are presented, including the drone simulation model and software. The drone model chosen for the simulations is available in the real world and widely used, such as the software and flight control unit. This relevant factor makes the transition to reality smoother and easier. Controllers using behavior trees were evolved using a developed evolutionary algorithm, and several experiments were conducted. Results demonstrated that it is possible to evolve a robotic controller in realistic simulation environments, using a simulated drone model that exists in the real world, and also the same flight control unit and operating system that is generally used in real world experiments.Atualmente os Veículos Não Tripulados (VNT) encontram-se difundidos por todo o Mundo. A maioria destes veículos requerem um elevado controlo humano, e o sucesso das missões está diretamente dependente deste fator. Assim, é importante utilizar técnicas de aprendizagem automática que irão treinar os controladores dos VNT, de modo a automatizar o controlo, tornando o processo mais eficiente. As estratégias evolutivas podem ser a chave para uma aprendizagem robusta e adaptativa em sistemas robóticos. Vários estudos têm sido realizados nos últimos anos, contudo, existem lacunas que precisam de ser abordadas, tais como o reality gap. Este facto ocorre quando os controladores treinados em ambientes simulados falham ao serem transferidos para VNT reais. Este trabalho propõe uma abordagem para a resolução de missões com VNT, utilizando um simulador realista e estratégias evolutivas para treinar controladores. A arquitetura escolhida é facilmente escalável para sistemas com múltiplos VNT. Nesta tese, é apresentada a arquitetura e configuração do ambiente de simulação, incluindo o modelo e software de simulação do VNT. O modelo de VNT escolhido para as simulações é um modelo real e amplamente utilizado, assim como o software e a unidade de controlo de voo. Este fator é relevante e torna a transição para a realidade mais suave. É desenvolvido um algoritmo evolucionário para treinar um controlador, que utiliza behavior trees, e realizados diversos testes. Os resultados demonstram que é possível evoluir um controlador em ambientes de simulação realistas, utilizando um VNT simulado mas real, assim como utilizando as mesmas unidades de controlo de voo e software que são amplamente utilizados em ambiente real

Implementação de um tradutor entre STANAG 4586 e MAVLink

O papel dos Unmanned Aerial Vehicles (UAVs) tem vindo a ganhar destaque nos últimos anos. Hoje em dia, estes veículos podem ser utilizados nas mais variadas missões, tanto para fins militares como para fins civis. Os UAVs dependem de uma estação de controlo, responsável pelo envio de comandos e pela receção dos dados obtidos pelo veículo. Para existir comunicação entre o UAV e a estação de controlo, é necessária a utilização de protocolos de comunicação. Contudo, ao existirem múltiplos protocolos deste tipo, é verificada uma grande falta de padronização nesta área. A consequência deste problema é a inexistência de interoperabilidade entre sistemas que utilizam protocolos diferentes. Esta dissertação visa responder a este problema através da criação de um tradutor entre dois dos protocolos de comunicação mais frequentemente utilizados: STANAG 4586 e MAVLink. O STANAG 4586 é um standard NATO e procura estabelecer uma uniformização para os UAVs dos países membros. O MAVLink, por sua vez, é um protocolo de comunicação bastante utilizado por vários pilotos automáticos, sendo assim uma referência na sua área. O desenvolvimento de um tradutor permitirá a interoperabilidade entre uma estação de controlo que utilize o standard STANAG 4586 e um UAV que utilize o protocolo MAVLink. Com a utilização do tradutor desenvolvido, não será necessário alterar a estrutura de um UAV para que este seja compatível com o standard STANAG 4586. O sistema proposto é desenvolvido com a linguagem de programação Python e com a utilização de um Raspberry Pi, hardware de fácil inserção em qualquer veículo. Esta investigação conta ainda com a criação de uma biblioteca de mensagens STANAG 4586, que permite a validação e obtenção de resultados nos cenários criados. Desta forma, são então testados vários cenários, através da utilização do simulador Software In the Loop (SITL). Os resultados demonstram que o tradutor realiza a conversão entre os dois protocolos de forma viável, não afetando as comunicações entre o UAV e a estação de controlo. No final são apresentadas conclusões, assim como propostas de trabalho futuro.The role of Unmanned Aerial Vehicles (UAVs) has been gaining prominence in recent years. Nowadays, these vehicles can be used in the most varied missions, both for military or civil purposes. The UAVs rely on a control station, responsible for sending commands and for receiving data obtained by the vehicle. In order to have communication between the UAV and the control station, communication protocols are required. However, since there are multiple protocols of this type, there is a great lack of standardization in this area. The consequence of this problem is the deficiency of interoperability between systems using different protocols. This dissertation aims to address this problem by creating a translator between two widely used communication protocols: STANAG 4586 e MAVLink. STANAG 4586 is a NATO standard and seeks to establish a standardization for UAVs country members. MAVLink, however, is a communication protocol broadly used by several autopilots, which makes it a reference in its area. The development of a translator will allow interoperability between a control station using the STANAG 4586 standard and a UAV using the MAVLink protocol. By using the developed translator, it will not be necessary to change the structure of the UAV to make it compatible with STANAG 4586. The proposed system is developed with Python programming language and with the use of a Raspberry Pi, which is easy to insert into any vehicle. In this research, a STANAG 4586 message library is also created, which allows to validate and obtain results from the created scenarios. Accordingly, several scenarios are then tested through the use of the Software In the Loop simulator (SITL). The results prove that the translator performs the conversion between the two protocols in a viable way, without affecting the communications between the UAV and the control station. Conclusions are presented at the end as well as future work proposals

Epidemiological aspects and characterization of the resistance profile of Fusarium spp. in patients with invasive fusariosis

Introduction. The remarkable intrinsic resistance of Fusarium species to most antifungal agents results in high mortality rates in the immunocompromised population. Aims. This study aimed to investigate the epidemiology, clinical features and antifungal susceptibility of Fusarium isolates in patients with invasive fusariosis. Methodology. A total of 27 patients admitted to a referral hospital from January 2008 to June 2017 were evaluated. Antifungal susceptibility testing of isolates was performed by broth microdilution according to the Clinical and Laboratory Standards Institute guidelines. Results. Haematological malignancy was the predominant underlying condition, with an incidence of invasive fusariosis of 14.8 cases per 1000 patients with acute lymphoid leukaemia and 13.1 cases per 1000 patients with acute myeloid leukaemia. The Fusarium solani species complex (FSSC) was the most frequent agent group, followed by the Fusarium oxysporum species complex (FOSC). Voriconazole showed the best activity against Fusarium, followed by amphotericin B. Itraconazole showed high minimum inhibitory concentration values, indicating in vitro resistance. Clinical FSSC isolates were significantly (P<0.05) more resistant to amphotericin B and voriconazole than FOSC isolates. Conclusion. The present antifungal susceptibility profiles indicate a high incidence of fusariosis in patients with haematological malignancy. Species- and strain-specific differences in antifungal susceptibility exist within Fusarium in this setting

New Insights on Innate Immune Response by Blood Macrophages and Liver Kupffer Cells to Leishmania infantum Parasites

Funding Information: Funding: This study was supported by FCT-Foundation for Science and Technology, I.P., through research grant PTDC/CVT-CVT/28908/2017 and PTDC/CVT-CVT/0228/2020, and by national funds within the scope of Centro de Investigação Interdisciplinar em Sanidade Animal (CIISA, UIDB/00276/2020) and Global Health and Tropical Medicine (GHTM, UID/04413/2020). Publisher Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland.L. infantum is the aetiological agent of zoonotic visceral leishmaniasis (ZVL), a disease that affects humans and dogs. Leishmania parasites are well adapted to aggressive conditions inside the phagolysosome and can control the immune activation of macrophages (MØs). Although MØs are highly active phagocytic cells with the capacity to destroy pathogens, they additionally comprise the host cells for Leishmania infection, replication, and stable establishment in the mammal host. The present study compares, for the first time, the innate immune response to L. infantum infection of two different macrophage lineages: the blood macrophages and the liver macrophages (Kupffer cells, KC). Our findings showed that L. infantum takes advantage of the natural predisposition of blood-MØs to phagocyte pathogens. However, parasites rapidly subvert the mechanisms of MØs immune activation. On the other hand, KCs, which are primed for immune tolerance, are not extensively activated and can overcome the dormancy induced by the parasite, exhibiting a selection of immune mechanisms, such as extracellular trap formation. Altogether, KCs reveal a different pattern of response in contrast with blood-MØs when confronting L. infantum parasites. In addition, KCs response appears to be more efficient in managing parasite infection, thus contributing to the ability of the liver to naturally restrain Leishmania dissemination.publishersversionpublishe

Insights on Host–Parasite Immunomodulation Mediated by Extracellular Vesicles of Cutaneous Leishmania shawi and Leishmania guyanensis

Funding Information: This study was supported by FCT-Foundation for Science and Technology, I.P., through research grant PTDC/CVT-CVT/28908/2017 and PTDC/CVT-CVT/0228/2020 and by national funds within the scope of Centro de Investigação Interdisciplinar em Sanidade Animal (CIISA, UIDB/00276/2020) and Global Health and Tropical Medicine (GHTM, UID/04413/2020). Publisher Copyright: © 2023 by the authors.Leishmaniasis is a parasitic disease caused by different species of Leishmania and transmitted through the bite of sand flies vector. Macrophages (MΦ), the target cells of Leishmania parasites, are phagocytes that play a crucial role in the innate immune microbial defense and are antigen-presenting cells driving the activation of the acquired immune response. Exploring parasite–host communication may be key in restraining parasite dissemination in the host. Extracellular vesicles (EVs) constitute a group of heterogenous cell-derived membranous structures, naturally produced by all cells and with immunomodulatory potential over target cells. This study examined the immunogenic potential of EVs shed by L. shawi and L. guyanensis in MΦ activation by analyzing the dynamics of major histocompatibility complex (MHC), innate immune receptors, and cytokine generation. L. shawi and L. guyanensis EVs were incorporated by MΦ and modulated innate immune receptors, indicating that EVs cargo can be recognized by MΦ sensors. Moreover, EVs induced MΦ to generate a mix of pro- and anti-inflammatory cytokines and favored the expression of MHCI molecules, suggesting that EVs antigens can be present to T cells, activating the acquired immune response of the host. Since nano-sized vesicles can be used as vehicles of immune mediators or immunomodulatory drugs, parasitic EVs can be exploited by bioengineering approaches for the development of efficient prophylactic or therapeutic tools for leishmaniasis.publishersversionpublishe

Performance of polymyxin B Etest in a setting of high prevalence of KPC-producing Klebsiella pneumoniae

Objectives: Polymyxin resistance has been increasing in many regions, and appropriate determination ofpolymyxin susceptibility is now a major challenge worldwide. Many clinical laboratories rely on gradientdiffusion methods to assess polymyxin susceptibility, although broth microdilution (BMD) is the onlymethod currently recommended by the CLSI and EUCAST. The aim of this study was to assess theperformance of the polymyxin B (PMB) Etest in a setting with a high prevalence of KPC-producingKlebsiella pneumoniae (KPC-KP).Methods: A commercial Etest susceptibility testing method was evaluated and compared with thereference BMD method, considering isolates with a minimum inhibitory concentration (MIC) 2 mg/L forPMB as susceptible to this drug. A total of 310 clinical KPC-KP isolates were evaluated.Results: Susceptibility was significantly higher by Etest compared with BMD (82.6% vs. 75.8%). The MIC50,MIC90and modal MICs for PMB were 0.25, 32 and 0.25 mg/L (27.1%) by BMD and 0.5, 16 and 0.5 mg/L(49.7%) by Etest, respectively. Although categorical agreement was 90.0%, there was poor essentialagreement (50.6%). A high rate (34.7%) of very major errors (VMEs) and a relatively low rate (2.1%) ofmajor errors were found.Conclusion: The considerable number of resistant isolates in this study allowed an accurate estimation ofVME rates and, consequently, a more comprehensive assessment of susceptibility testing for polymyxins.Etest did not meet fully the acceptance criteria for US FDA requirements. These data do not support theuse of this commercial method for determining PMB MICs in carbapenem-resistant Enterobacterales populations

immune activation of canine hepatic spheroids exposed to leishmania infantum

The application of innovative three-dimensional (3D) spheroids cell culture strategy to Parasitology offers the opportunity to closely explore host–parasite interactions. Here we present a first report on the application of 3D hepatic spheroids to unravel the immune response of canine hepatocytes exposed to Leishmania infantum. The liver, usually considered a major metabolic organ, also performs several important immunological functions and constitutes a target organ for L. infantum infection, the etiological agent of canine leishmaniasis (CanL), and a parasitic disease of major veterinary and public health concern. 3D hepatic spheroids were able to sense and immunologically react to L. infantum parasites, generating an innate immune response by increasing nitric oxide (NO) production and enhancing toll-like receptor (TLR) 2 and interleukin-10 gene expression. The immune response orchestrated by canine hepatocytes also lead to the impairment of several cytochrome P450 (CYP450) with possible implications for liver natural xenobiotic metabolization capacity. The application of meglumine antimoniate (MgA) increased the inflammatory response of 3D hepatic spheroids by inducing the expression of Nucleotide oligomerization domain (NOD)-like receptors 1 and NOD2 and TLR2, TLR4, and TLR9 and enhancing gene expression of tumour necrosis factor α. It is therefore suggested that hepatocytes are key effector cells and can activate and orchestrate the immune response to L. infantum parasites.publishersversionpublishe

Production of drinking water using a multi-barrier approach integrating nanofiltration: a pilot scale study

A multi-barrier system was studied for the production of drinking water with high chemical and microbiological quality. The integration of nanofiltration (NF) and ultraviolet (UV) photolysis was tested at pilot scale in a surface water treatment plant. The NF membranes tested, Desal DK and NF270, allow for the production of permeates with high quality standards, although the membrane with higher molecular weight cut-off (NF270) revealed to be the best option for surface water treatment due to its higher permeability. The NF270 membrane was also efficient to deliver high quality water, even under high pollutant concentrations, making possible to operate with water recovery rates as high as 98%. Extensive studies were performed in the water treatment plant where the proposed system was tested at three locations of the drinking water production line. Seeking to achieve the best compromise between high recovery rate, high retention of chemicals and microorganisms as well as preventing operational problems (flux decline and fouling), it was found that the integrated system should be placed after the conventional sand filtration, operating at a 91% recovery rate. Under the selected conditions – TMP of 8 bar and recovery rate of 91% – it is possible to operate at constant permeability without flux decline for a period of 15 days, after which a gentle CIP procedure is recommended. Membrane fouling was also investigated and the major foulant classes identified were proteins, polysaccharides and humic acids. A cleaning protocol was also tested and the impact of each cleaning step on the recovery of permeability evaluated