168 research outputs found

    ROS based autonomous control of a humanoid robot

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    International audienceThis paper presents an artificial neural network-based control architecture allowing autonomous mobile robot indoor navigation by emulating the cognition process of a human brain when navigating in an unknown environment. The proposed architecture is based on a simultaneous top-down and bottom up approach, which combines the a priori knowledge of the environment gathered from a previously examined floor plan with the visual information acquired in real time. Thus, in order to take the right decision during navigation, the robot is able to process both set of information, compare them in real time and react accordingly. The architecture is composed of two modules: a) A deliberative module, corresponding to the processing chain in charge of extracting a sequence of navigation signs expected to be found in the environment, generating an optimal path plan to reach the goal,computing and memorizing the sequence of signs [1]. The path planning stage allowing the computation of the sign sequence is based on a neural implementation of the resistive grid. b) A reactive module, integrating the said sequence information in order to use it to control online navigation and learning sensory-motor associations. It follows a perception-action mechanism that constantly evolves because of the dynamic interaction between the robot and its environment. It is composed of three layers: one layer using a cognitive mechanism and the other two using a reflex mechanism. Experimental results obtained from the physical implementation of the architecture in an indoor environment show the feasibility of this approach

    Using robot operating system (ROS) and single board computer to control bioloid robot motion

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    This paper presents a research study on the adaptation of a novel technique for placing a programmable component over the structural component of a Robotis Bioloid humanoid robot. Assimilating intelligence plays an important role in the field of robotics that enables a computer to model or replicate some of the intelligent behaviors of human beings but with minimal human intervention. As a part of this effort, this paper revises the Bioloid robot structure so as to be able to control the robotic movement via a single board computer Beaglebone Black (BBB) and Robot operating system (ROS). ROS as the development frame work in conjunction with the main BBB controller that integrates robotic functions is an important aspect of this research, and is a first of its kind approach. A full ROS computation has been developed by which an API that will be usable by high level software using ROS services has also been developed. The human like body structure of the Bioloid robot and BeagleBone Black running ROS along with the intellectual components are used to make the robot walk efficiently

    Generalized r-matrix structure and algebro-geometric solution for integrable systems

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    The purpose of this paper is to construct a generalized r-matrix structure of finite dimensional systems and an approach to obtain the algebro-geometric solutions of integrable nonlinear evolution equations (NLEEs). Our starting point is a generalized Lax matrix instead of usual Lax pair. The generalized r-matrix structure and Hamiltonian functions are presented on the basis of fundamental Poisson bracket. It can be clearly seen that various nonlinear constrained (c-) and restricted (r-) systems, such as the c-AKNS, c-MKdV, c-Toda, r-Toda, c-Levi, etc, are derived from the reduction of this structure. All these nonlinear systems have {\it r}-matrices, and are completely integrable in Liouville's sense. Furthermore, our generalized structure is developed to become an approach to obtain the algebro-geometric solutions of integrable NLEEs. Finally, the two typical examples are considered to illustrate this approach: the infinite or periodic Toda lattice equation and the AKNS equation with the condition of decay at infinity or periodic boundary.Comment: 41 pages, 0 figure

    Research on the Impact of Executive Shareholding on New Investment in Enterprises Based on Multivariable Linear Regression Model

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    Based on principal-agent theory and optimal contract theory, companies use the method of increasing executives' shareholding to stimulate collaborative innovation. However, from the aspect of agency costs between management and shareholders (i.e. the first type) and between major shareholders and minority shareholders (i.e. the second type), the interests of management, shareholders and creditors will be unbalanced with the change of the marginal utility of executive equity incentives.In order to establish the correlation between the proportion of shares held by executives and investments in corporate innovation, we have chosen a range of publicly listed companies within China's A-share market as the focus of our study. Employing a multi-variable linear regression model, we aim to analyze this relationship thoroughly.The following models were developed: (1) the impact model of executive shareholding on corporate innovation investment; (2) the impact model of executive shareholding on two types of agency costs; (3)The model is employed to examine the mediating influence of the two categories of agency costs. Following both correlation and regression analyses, the findings confirm a meaningful and positive correlation between executives' shareholding and the augmentation of corporate innovation investments. Additionally, the results indicate that executive shareholding contributes to the reduction of the first type of agency cost, thereby fostering corporate innovation investment. However, simultaneously, it leads to an escalation in the second type of agency cost, thus impeding corporate innovation investment.Comment: Accepted by the 7th APWeb-WAIM International Joint Conference on Web and Big Data. (APWeb 2023

    Crystal Structure of the Cysteine Desulfurase DndA from Streptomyces lividans Which Is Involved in DNA Phosphorothioation

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    DNA phosphorothioation is widespread among prokaryotes, and might function to restrict gene transfer among different kinds of bacteria. There has been little investigation into the structural mechanism of the DNA phosphorothioation process. DndA is a cysteine desulfurase which is involved in the first step of DNA phosphorothioation. In this study, we determined the crystal structure of Streptomyces lividans DndA in complex with its covalently bound cofactor PLP, to a resolution of 2.4 Å. Our structure reveals the molecular mechanism that DndA employs to recognize its cofactor PLP, and suggests the potential binding site for the substrate L-cysteine on DndA. In contrast to previously determined structures of cysteine desulfurases, the catalytic cysteine of DndA was found to reside on a β strand. This catalytic cysteine is very far away from the presumable location of the substrate, suggesting that a conformational change of DndA is required during the catalysis process to bring the catalytic cysteine close to the substrate cysteine. Moreover, our in vitro enzymatic assay results suggested that this conformational change is unlikely to be a simple result of random thermal motion, since moving the catalytic cysteine two residues forward or backward in the primary sequence completely disabled the cysteine desulfurase activity of DndA

    Wrist movement detector for ROS based control of the robotic hand

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    Robotic hands are used in a wide range of applications. They have many different shapes, constructions and capabilities. This work presents a new design of a robotic hand using tailor-made as well as widely available sensors and actuators. The information transferred between the sensor and actuators is processed using the Robot Operating System (ROS) topic mechanism. The robotic hand movement is remotely controlled by a movement detector mounted on the wrist of a human hand controller. Based on this simple hardware setup we demonstrate that the robotic hand can be remotely opened and closed thereby allowing to grasp objects flexibly

    The prognostic value of high expression of FKBP1A in gastric cancer and the regulatory effect of targeted PI3K/AKT on glucose metabolism

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    Background and purpose: Gastric cancer is one of the common gastrointestinal malignancies. FKBP1A has been reported to be involved in the occurrence and development of various tumors, but the biological role and mechanism of it in gastric cancer remain unclear. This study aimed to investigate the expression level and prognostic value of FKBP1A in gastric cancer tissues, and to analyze the possible pathways and mechanisms of its regulation of gastric cancer progression. Methods: The expression of FKBP1A in gastric cancer was observed by immunohistochemistry, and its correlation with poor prognosis was analyzed by combining bioinformatics and clinicopathological parameters. Kaplan-Meier survival curve was used to analyze the effect of FKBP1A on the 5-year survival rate of patients with gastric cancer after surgery, and COX multivariate regression analysis was used to explore the independent prognostic factors affecting the 5-year survival rate of patients with gastric cancer after surgery. The diagnostic value of FKBP1A expression in patients with gastric cancer was analyzed using receiver operating characteristic (ROC) curve. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) were used to enrich and analyze the biological function of FKBP1A and the possible signal pathways involved. We constructed the MGC803 cell model transfected with lentivirus in vitro, explored the influence of FKBP1A on the glucose metabolism and malignant biological behavior of MGC803 cells, and the possible molecular mechanism involved, and established a nude mouse transplantation tumor model in vitro to verify it. Results: Immunohistochemical results showed that FKBP1A was highly expressed in gastric cancer (P<0.01), and bioinformatics and clinical parameter analysis showed that FKBP1A was associated with poor prognosis. Kaplan-Meier survival analysis and COX regression analysis showed that the expression level of FKBP1A was negatively correlated with 5-year survival. And carcinoembryonic antigen (CEA)≥5 μg/L, carbohydrate antigen (CA) 19-9≥37 kU/L, T stage (T3-T4) and N stage (N2-N3) were independent prognostic factors affecting the 5-year survival rate of gastric cancer patients after surgery (P<0.05). ROC analysis showed that high expression of FKBP1A had good prognostic value (P<0.01). Enrichment of GO and KEGG suggested that FKBP1A was involved in regulating glucose metabolism in gastric cancer cells. In vitro experiments showed that overexpression of FKBP1A promoted glucose metabolism and proliferation, invasion and migration of MGC803 cells, while silencing of FKBP1A did the opposite (P<0.05). In vivo experiments showed that overexpression of FKBP1A in gastric cancer cells promoted the growth of transplanted tumor in nude mice, while silencing FKBP1A inhibited it (P<0.05). Mechanism analysis showed that overexpression of FKBP1A upregulated the expressions of phosphatidylinositol 3-kinase (PI3K) and protein kinase B (AKT) in gastric cancer cells, while silencing FKBP1A downregulated the expressions (P<0.05). Conclusion: FKBP1A is highly expressed in gastric cancer tissues, and is associated with poor prognosis, which may be due to the promotion of glucose metabolism and malignant biological behavior of gastric cancer cells by activating PI3K/AKT

    Key elements in assessing circular economy implementation in small and medium-sized enterprises

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    The circular economy has become an important issue in recent years because itmakes sustainable development feasible by creating value in the economy and byclosing the energy and materials loops. However, since most companies continueto operate under a linear model, it is particularly important to start providingcompanies with tools that facilitate their shift to the circular paradigm. The mainobjective of this research is to establish the key elements that are necessary forassessing the level of circular economy implementation. To that end, the Delphimethod is used to validate and define the key elements of three categories: circulareconomy fields of action, industrial symbiosis, and environmental certifications. Asa result, this study identifies the key elements that assess the degree of circulareconomy implementation and that allows small and medium‐sized enterprisesto understand where they are and what they need to do to improve theirperformance
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