956 resultados para Mobile robot systems


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In this paper a 6-RRCRR parallel robot assisted minimally invasive surgery/microsurgery system (PRAMiSS) is introduced. Remote centre-of-motion (RCM) control algorithms of PRAMiSS suitable for minimally invasive surgery and microsurgery are also presented. The programmable RCM approach is implemented in order to achieve manipulation under the constraint of moving through the fixed penetration point. Having minimised the displacements of the mobile platform of the parallel micropositioning robot, the algorithms also apply orientation constraint to the instrument and prevent the tool tip to orient due to the robot movements during the manipulation. Experimental results are provided to verify accuracy and effectiveness of the proposed RCM control algorithms for minimally invasive surgery.

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As mobile devices have become the personal information-processing interface of choice, many individuals seem to swiftly follow fashion. Yet, the literature is silent on how early adopters of mobile devices overcome uncertainties related to shifts in technology. Based on purposive sampling, this paper presents detailed insights into why and how five closely related individuals made the decision to adopt the iPhone before it was available through traditional supply chains. Focusing on the role played by social networks, we analyze how adoption threshold, opinion leaders, social contagion, and social learning shaped adoption behaviors and outcomes. The analyses confirm that network structures impacted the early decision to accept the iPhone; they show that when facing uncertainty, adoption decisions emerged as a combined result of individual adoption reflections and major influences from the social network as well as behaviors observed within the network; and, they reveal interesting behaviors that differed from expectations. In conclusion, we discuss implications for both theory and practice.

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This paper contains findings based on administering a Likert-type mobile learning attitude survey to 261 university students from four nations, China, Lebanon, the UAE and the USA. Students were asked to provide attitudes and perceptions toward the use of mobile technologies in education. The results of the survey indicate that students in different regions of the world tend to agree that mobile learning could empower informal learning and could enhance teaching and learning. Lebanon students were most similar to those from the USA, while students from China were more similar to those from the UAE. Similarities and differences in results among nations and implications of these findings are discussed.

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 Mobile platform security solution has become especially important for mobile computing paradigms, due to the fact that increasing amounts of private and sensitive information are being stored on the smartphones' on-device memory or MicroSD/SD cards. This paper aims to consider a comparative approach to the security aspects of the current smartphone systems, including: iOS, Android, BlackBerry (QNX), and Windows Phone.

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Existing solutions to carrier-based sensor placement by a single robot in a bounded unknown Region of Interest (ROI) do not guarantee full area coverage or termination. We propose a novel localized algorithm, named Back-Tracking Deployment (BTD). To construct a full coverage solution over the ROI, mobile robots (carriers) carry static sensors as payloads and drop them at the visited empty vertices of a virtual square, triangular, or hexagonal grid. A single robot will move in a predefined order of directional preference until a dead end is reached. Then it back-tracks to the nearest sensor adjacent to an empty vertex (an "entrance" to an unexplored/uncovered area) and resumes regular forward movement and sensor dropping from there. To save movement steps, the back-tracking is carried out along a locally identified shortcut. We extend the algorithm to support multiple robots that move independently and asynchronously. Once a robot reaches a dead end, it will back-track, giving preference to its own path. Otherwise, it will take over the back-track path of another robot by consulting with neighboring sensors. We prove that BTD terminates within finite time and produces full coverage when no (sensor or robot) failures occur. We also describe an approach to tolerate failures and an approach to balance workload among robots. We then evaluate BTD in comparison with the only competing algorithms SLD [Chang et al. 2009a] and LRV [Batalin and Sukhatme 2004] through simulation. In a specific failure-free scenario, SLD covers only 40-50% of the ROI, whereas BTD covers it in full. BTD involves significantly (80%) less robot moves and messages than LRV.

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Learning management systems (LMS) have been a popular tool for delivery of learning content as well as the management of learners and courses. In recent years, the ubiquity of mobile devices such as smartphones and tablets has seen the increased popularity of using them to consume eBooks. While the LMS is popular among administrators, accessing content on mobile devices appear to be the preference of our learners. Furthermore, there are reports on a number of shortcomings with learners using the LMS, e.g., the experience of using LMSes on mobile devices falling short and learners are less engaged interacting with the LMS than with their mobile devices, etc. In this paper, we investigate the idea of using eBooks as an alternative frontend for learners to interact with the LMS. A proof of concept eBook was developed for a data management course to showcase how content on the LMS can be deployed via the eBook interface while connecting our learners to the LMS for learning management. We find that this approach delivers a rich and immersive experience to our learners, as they would expect from their devices. The outcomes also gave us food for thought regarding how LMSes may evolve in the future.

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Mobile Teachers, Teacher Identity and International Schooling focuses on the increased mobility of teachers and curriculum and what it means for the expansion of international schooling. In the early 21st century, educational institutions have been transformed by technological innovation and global interconnectivity. The demographic, ideological, economic and cultural flows that integrate local and global interconnections have consequences for the ways in which educational policy, theories and practice can be understood and take place locally. The everyday lives of practitioners, parents and students; the institutions in which they are educated and work; and the sociocultural and ideological contexts in which they work, are all consequently changing. The manifestation of these changes – as evident in the work and lives of teachers within specific cultural contexts and education systems; in their implications for educational theory and methodology; and their consequences for policy, programs, practice and research in education – are the focus of this book.This book explores the mobility of curriculum, pedagogies, ideas and people that represent and mediate the impact of Global uneven flows and movements through, in, and for school education, and the concepts and practices which frame that transformation. The particular focus of the book is on how these flows inform the ways individuals negotiate their identities, cultures and languages in different national and educational contexts. Education systems and the educational experiences offered by schools are being reconfigured due to multiple pressures. What do these moves to mobilise and to work transnationally mean in terms of educational provision, possibilities and practice?

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In this study, we proposed an adaptive fuzzy multi-surface sliding control (AFMSSC) for trajectory tracking of 6 degrees of freedom inertia coupled aerial vehicles with multiple inputs and multiple outputs (MIMO). It is shown that an adaptive fuzzy logic-based function approximator can be used to estimate the system uncertainties and an iterative multi-surface sliding control design can be carried out to control flight. Using AFMSSC on MIMO autonomous flight systems creates confluent control that can account for both matched and mismatched uncertainties, system disturbances and excitation in internal dynamics. It is proved that the AFMSSC system guarantees asymptotic output tracking and ultimate uniform boundedness of the tracking error. Simulation results are presented to validate the analysis.

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Two sulfonated ionomers based on poly(triethylmethyl ammonium 2-acrylamido-2-methyl-1-propane sulfonic acid) (PAMPS) and containing mixtures of Li+ and quaternary ammonium cations are characterised. The first system contains Li+ and the methyltriethyl ammonium cation (N1222) in a 1:9 molar ratio, and the 7Li NMR line widths showed that the Li+ ions are mobile in this system below the glass transition temperature (105°C) and are therefore decoupled from the polymer segmental motion. The conductivity in this system was measured as 10-5 Scm-1 at 130°C. A second PAMPS system containing Li+ and the dimethylbutylmethoxyethyl ammonium cation (N114(2O1)) in a 2:8 molar ratio showed much lower conductivities despite a significantly lower Tg (60°C), possibly due to associations between the Li+ and the ether group on the ammonium cation, or between the latter cations and the sulfonate groups.

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MEDEIROS, Adelardo A. D.A survey of control architectures for autonomous mobile robots. J. Braz. Comp. Soc., Campinas, v. 4, n. 3, abr. 1998 .Disponível em: Acesso: 27 set. 2010.

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The development of robots has shown itself as a very complex interdisciplinary research field. The predominant procedure for these developments in the last decades is based on the assumption that each robot is a fully personalized project, with the direct embedding of hardware and software technologies in robot parts with no level of abstraction. Although this methodology has brought countless benefits to the robotics research, on the other hand, it has imposed major drawbacks: (i) the difficulty to reuse hardware and software parts in new robots or new versions; (ii) the difficulty to compare performance of different robots parts; and (iii) the difficulty to adapt development needs-in hardware and software levels-to local groups expertise. Large advances might be reached, for example, if physical parts of a robot could be reused in a different robot constructed with other technologies by other researcher or group. This paper proposes a framework for robots, TORP (The Open Robot Project), that aims to put forward a standardization in all dimensions (electrical, mechanical and computational) of a robot shared development model. This architecture is based on the dissociation between the robot and its parts, and between the robot parts and their technologies. In this paper, the first specification for a TORP family and the first humanoid robot constructed following the TORP specification set are presented, as well as the advances proposed for their improvement.

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This paper aims at describing an educational system for teaching and learning robotic systems. Multimedia resources were used to construct a virtual laboratory where users are able to use functionalities of a virtual robotic arm, by moving and clicking the mouse without caring about the detailed internal robot operation. Moreover through the multimedia system the user can interact with a real robot arm. The engineering students are the target public of the developed system. With its contents and interactive capabilities, it has been used as a support to the traditional face-to-face classes on the subject of robotics.. In the paper it is first introduced the metaphor of Virtual Laboratory used in the system. Next, it is described the Graphical and Multimedia Environment approach: an interactive graphic user interface with a 3D environment for simulation. Design and implementation issues of the real-time interactive multimedia learning system, which supports the W3C SMIL standard for presenting the real-time multimedia teaching material, are described. Finally, some preliminary conclusions and possible future works from this research are presented.

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This paper presents an approach to integrate an artificial intelligence (AI) technique, concretely rule-based processing, into mobile agents. In particular, it focuses on the aspects of designing and implementing an appropriate inference engine of small size to reduce migration costs. The main goal is combine two lines of agent research, First, the engineering oriented approach on mobile agent architectures, and, second, the AI related approach on inference engines driven by rules expressed in a restricted subset of first-order predicate logic (FOPL). In addition to size reduction, the main functions of this type of engine were isolated, generalized and implemented as dynamic components, making possible not only their migration with the agent, but also their dynamic migration and loading on demand. A set of classes for representing and exchanging knowledge between rule-based systems was also proposed.

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This paper describes the development of a multimedia educational system to teach and learn robotic systems. Multimedia resources have been used to build a virtual laboratory where users are able to utilize functions of a robotic arm, by moving and clicking the mouse without worrying about the detailed robot internal operation. The multimedia system is integrated with a real robotic arm, which was also developed at the university. Through robotic topic presentations and interactive capabilities provided by this system and its tools, students can devote themselves on the learning process just as they do in the traditional face-to-face classes. and the target public of this system are the engineering students themselves.