WorldWideScience

Sample records for grasp key concepts

  1. Modular Connector Keying Concept

    Science.gov (United States)

    Ishman, Scott; Dukes, Scott; Warnica, Gary; Conrad, Guy; Senigla, Steven

    2013-01-01

    For panel-mount-type connectors, keying is usually "built-in" to the connector body, necessitating different part numbers for each key arrangement. This is costly for jobs that require small quantities. This invention was driven to provide a cost savings and to reduce documentation of individual parts. The keys are removable and configurable in up to 16 combinations. Since the key parts are separate from the connector body, a common design can be used for the plug, receptacle, and key parts. The keying can then be set at the next higher assembly.

  2. The Grasp of Physics Concepts of Motion: Identifying Particular Patterns in Students' Thinking

    Science.gov (United States)

    Obaidat, Ihab; Malkawi, Ehab

    2009-01-01

    We have investigated the grasp of some of the basic concepts of motion by students taking the introductory physics course in Mechanics at United Arab Emirates University (UAEU). We have developed a short research-based multiple-choice test where we were able to extract some information about the state of knowledge of the students. In general, the…

  3. Globalization: grasping the concept within the context of nursing.

    Science.gov (United States)

    Keighley, Tom

    2013-03-01

    Globalization is a phenomenon traceable historically from the beginning of time as clans and tribes migrated and learnt from each other. The article in this issue of INR by Grootjans and Newman 'Globalization and nursing: a concept analysis' (pp. 78-85) makes the case for nurses to be educated about globalization as it applies to modern health care. The concept is complex and requires insight not only into health care itself but also fields such as human migration, economics, the significance of English as a universal language and the use and availability of information technology. Writings on the impact of global technology and social capital are also important. In addressing globalization, nurses need to access research and writings well beyond the standard healthcare oeuvre. © 2013 The Author. International Nursing Review © 2013 International Council of Nurses.

  4. Key Concepts in Microbial Oceanography

    Science.gov (United States)

    Bruno, B. C.; Achilles, K.; Walker, G.; Weersing, K.; Team, A

    2008-12-01

    The Center for Microbial Oceanography: Research and Education (C-MORE) is a multi-institution Science and Technology Center, established by the National Science Foundation in 2006. C-MORE's research mission is to facilitate a more comprehensive understanding of the diverse assemblages of microorganisms in the sea, ranging from the genetic basis of marine microbial biogeochemistry including the metabolic regulation and environmental controls of gene expression, to the processes that underpin the fluxes of carbon, related bioelements, and energy in the marine environment. The C-MORE education and outreach program is focused on increasing scientific literacy in microbial oceanography among students, educators, and the general public. A first step toward this goal is defining the key concepts that constitute microbial oceanography. After lengthy discussions with scientists and educators, both within and outside C-MORE, we have arrived at six key concepts: 1) Marine microbes are very small and have been around for a long time; 2) Life on Earth could not exist without microbes; 3) Most marine microbes are beneficial; 4) Microbes are everywhere: they are extremely abundant and diverse; 5) Microbes significantly impact our global climate; and 6) There are new discoveries every day in the field of microbial oceanography. A C-MORE-produced brochure on these six key concepts will be distributed at the meeting. Advanced copies may be requested by email or downloaded from the C-MORE web site(http://cmore.soest.hawaii.edu/downloads/MO_key_concepts_hi-res.pdf). This brochure also includes information on career pathways in microbial oceanography, with the aim of broadening participation in the field. C-MORE is eager to work in partnership to incorporate these key concepts into other science literacy publications, particularly those involving ocean and climate literacy. We thank the following contributors and reviewers: P Chisholm, A Dolberry, and A Thompson (MIT); N Lawrence

  5. From grasp to language: embodied concepts and the challenge of abstraction.

    Science.gov (United States)

    Arbib, Michael A

    2008-01-01

    The discovery of mirror neurons in the macaque monkey and the discovery of a homologous "mirror system for grasping" in Broca's area in the human brain has revived the gestural origins theory of the evolution of the human capability for language, enriching it with the suggestion that mirror neurons provide the neurological core for this evolution. However, this notion of "mirror neuron support for the transition from grasp to language" has been worked out in very different ways in the Mirror System Hypothesis model [Arbib, M.A., 2005a. From monkey-like action recognition to human language: an evolutionary framework for neurolinguistics (with commentaries and author's response). Behavioral and Brain Sciences 28, 105-167; Rizzolatti, G., Arbib, M.A., 1998. Language within our grasp. Trends in Neuroscience 21(5), 188-194] and the Embodied Concept model [Gallese, V., Lakoff, G., 2005. The brain's concepts: the role of the sensory-motor system in reason and language. Cognitive Neuropsychology 22, 455-479]. The present paper provides a critique of the latter to enrich analysis of the former, developing the role of schema theory [Arbib, M.A., 1981. Perceptual structures and distributed motor control. In: Brooks, V.B. (Ed.), Handbook of Physiology--The Nervous System II. Motor Control. American Physiological Society, pp. 1449-1480].

  6. Key concepts in social pedagogy

    DEFF Research Database (Denmark)

    Harbo, Lotte Junker

    2011-01-01

    and activities around key social pedagogical concepts, such as the Common Third, the 3 P’s, the Zone of Proximal Development and the Learning Zone model. In the article we explore how a joint activity, for example playing soccer, can be seen as a pedagogical activity and with what intentions it is undertaken......“Now I can actually play soccer with the young people without fearing that my colleagues think I am escaping the paper work.” These were the words from a participant in a social pedagogy training course in England a few years ago. This understanding emerged through in-depth discussions...

  7. Key concepts in glioblastoma therapy

    DEFF Research Database (Denmark)

    Bartek, Jiri; Ng, Kimberly; Bartek, Jiri

    2012-01-01

    principles that drive the formulation of therapeutic strategies in glioblastoma. Specifically, the concepts of tumour heterogeneity, oncogene addiction, non-oncogene addiction, tumour initiating cells, tumour microenvironment, non-coding sequences and DNA damage response will be reviewed....

  8. Optimal grazing management strategies: evaluating key concepts ...

    African Journals Online (AJOL)

    Finally, overstocking will override key management initiatives, such as effective recovery periods, leading to rangeland degradation. Thus, in variable climates, stocking rate should be set conservatively to allow easier adaptation of animal numbers to rainfall variability from year to year. We suggest several key concepts that ...

  9. Active Grasp Synthesis for Grasping Unknown Objects

    NARCIS (Netherlands)

    Çall?, B.

    2015-01-01

    Manipulation is a key feature for robots which are designed to work in daily environments like homes, offices and streets. These robots do not often have manipulators that are specialized for specific tasks, but grippers that can grasp the target object. This makes grasping a crucial ability that

  10. Grasp Densities for Grasp Refinement in Industrial Bin Picking

    DEFF Research Database (Denmark)

    Hupfauf, Benedikt; Hahn, Heiko; Bodenhagen, Leon

    in terms of object-relative gripper pose, can be learned from empirical experience, and allow the automatic choice of optimal grasps in a given scene context (object pose, workspace constraints, etc.). We will show grasp densities extracted from empirical data in a real industrial bin picking context...... generated in industrial bin-picking for grasp learning. This aim is achieved by using the novel concept of grasp densities (Detry et al., 2010). Grasp densities can describe the full variety of grasps that apply to specific objects using specific grippers. They represent the likelihood of grasp success...

  11. Utilization of old vibro-acoustic measuring equipment to grasp basic concepts of vibration measurements

    DEFF Research Database (Denmark)

    Darula, Radoslav

    2013-01-01

    The aim of the paper is to show that even old vibro-acoustic (analog) equipment can be used as a very suitable teaching equipment to grasp basic principles of measurements in an era, when measurement equipments are more-or-less treated as ‘black-boxes’, i.e. the user cannot see directly how...

  12. Accountability in district nursing practice: key concepts.

    Science.gov (United States)

    Griffith, Richard

    2015-03-01

    Public trust and confidence in district nurses is essential to the nurse-patient relationship that underpins effective care and treatment. That trust and confidence has even greater focus for district nurses who care for patients in their own homes. Those patients need to be able to count on the professionalism and probity of their district nurses. The professionalism and probity of district nurses is based on their accountability, which protects the public by imposing standards on district nurses and holds them answerable for their acts and omissions. This is the first of a series of articles on accountability in district nursing practice to mark the introduction of the revised Nursing and Midwifery Code on the 31 March 2015. This month's article considers the key concepts of accountability.

  13. Key Concept Mathematics and Management Science Models

    Science.gov (United States)

    Macbeth, Thomas G.; Dery, George C.

    1973-01-01

    The presentation of topics in calculus and matrix algebra to second semester freshmen along with a treatment of exponential and power functions would permit them to cope with a significant portion of the mathematical concepts that comprise the essence of several disciplines in a business school curriculum. (Author)

  14. Key concepts of the INCAS multicomputer project

    Energy Technology Data Exchange (ETDEWEB)

    Nehmer, J.; Haban, D.; Mattern, F.; Wybranietz, D.; Rombach, H.D.

    1987-08-01

    This paper gives an overview of the INCAS (INCremental Architecture for distributed Systems) multicomputer project, which aims at the development of a comprehensive methodology for the design and implementation of locally distributed systems. A structuring concept for distributed operating systems has been developed and integrated into the system implementation language LADY. The concurrent high-level programming language CSSA, based on the actor model, has been designed for the implementation of distributed applications. A substantial effort in the INCAS project is directed towards the development of a distributed test methodology. An experimental system has been implemented on a network of ten MC68000 microcomputers. Preliminary experience with the methodology has been gained from a small number of prototype applications.

  15. KEY CONCEPTS OF AGROECOLOGY SCIENCE. A SYSTEMATIC REVIEW

    Directory of Open Access Journals (Sweden)

    Luis Fernando Gómez-Echeverri

    2016-08-01

    Full Text Available A systematic review was conducted with the objective of determining the key concepts that are currently used in theoretical work in agroecology. They were obtained from titles and keywords of theoretical articles and books that included the term agroecology in the title. Fifteen terms with occurrences higher than three were obtained. They show that agroecology revolves around the concept of integral sustainability, and that there is agreement on neither its object of study nor goal. As a result, most key concepts concern the object of study or the goal of agroecology. Other key concepts are food sovereignty, agriculture, ecofeminism, climate change, family farming, and social movements.

  16. What a successful grasp tells about the success chances of grasps in its vicinity

    DEFF Research Database (Denmark)

    Bodenhagen, Leon; Detry, Renaud; Piater, Justus

    2011-01-01

    Infants gradually improve their grasping competences, both in terms of motor abilities as well as in terms of the internal shape grasp representations. Grasp densities provide a statistical model of such an internal learning process. In the concept of grasp densities, kernel density estimation...... probabilities representing grasp success in the neighborhood of a successful grasp. The anisotropy has been determined utilizing a simulation environment that allowed for evaluation of large scale experiments. The anisotropic kernel has been fitted to the conditional probabilities obtained from the experiments...

  17. Digital games in medical education: Key terms, concepts, and definitions.

    Science.gov (United States)

    Bigdeli, Shoaleh; Kaufman, David

    2017-01-01

    Introduction: Game-based education is fast becoming a key instrument in medical education. Method: In this study, papers related to games were filtered and limited to full-text peer-reviewed published in English. Results: To the best of researchers' knowledge, the concepts used in the literature are varied and distinct, and the literature is not conclusive on the definition of educational games for medical education. Conclusion: This paper attempts to classify terms, concepts and definitions common to gamification in medical education.

  18. TEN KEY CONCEPTS AND THE SUCCESS OF ROMANIAN ORGANIZATIONS

    Directory of Open Access Journals (Sweden)

    Ada Mirela TOMESCU

    2006-01-01

    Full Text Available This paper is focused on ten key concepts which influence the success of theorganizations at the beginning of XXI century. The great changes generatedby globalization determine firms to be more competitive. This means that wehave to focus on: mission, leadership, emotional intelligence, innovation,organizational culture, human resources, total quality management, ethics,conflict management, brand, and the value offered to the clients.

  19. Review of key concepts in magnetic resonance physics

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Michael M. [Penn State Hershey Children' s Hospital, Department of Radiology, The Pennsylvania State College of Medicine, Hershey, PA (United States); Chung, Taylor [UCSF Benioff Children' s Hospital Oakland, Department of Diagnostic Imaging, Oakland, CA (United States)

    2017-05-15

    MR physics can be a challenging subject for practicing pediatric radiologists. Although many excellent texts provide very comprehensive reviews of the field of MR physics at various levels of understanding, the authors of this paper explain several key concepts in MR physics that are germane to clinical practice in a non-rigorous but practical fashion. With the basic understanding of these key concepts, practicing pediatric radiologists can build on their knowledge of current clinical MR techniques and future advances in MR applications. Given the challenges of both the increased need for rapid imaging in non-sedated children and the rapid physiological cardiovascular and respiratory motion in pediatric patients, many advances in complex MR techniques are being applied to imaging these children. The key concepts are as follows: (1) structure of a pulse sequence, (2) k-space, (3) ''trade-off triangle'' and (4) fat suppression. This review is the first of five manuscripts in a minisymposium on pediatric MR. The authors' goal for this review is to aid in understanding the MR techniques described in the subsequent manuscripts on brain imaging and body imaging in this minisymposium. (orig.)

  20. Review of key concepts in magnetic resonance physics.

    Science.gov (United States)

    Moore, Michael M; Chung, Taylor

    2017-05-01

    MR physics can be a challenging subject for practicing pediatric radiologists. Although many excellent texts provide very comprehensive reviews of the field of MR physics at various levels of understanding, the authors of this paper explain several key concepts in MR physics that are germane to clinical practice in a non-rigorous but practical fashion. With the basic understanding of these key concepts, practicing pediatric radiologists can build on their knowledge of current clinical MR techniques and future advances in MR applications. Given the challenges of both the increased need for rapid imaging in non-sedated children and the rapid physiological cardiovascular and respiratory motion in pediatric patients, many advances in complex MR techniques are being applied to imaging these children. The key concepts are as follows: (1) structure of a pulse sequence, (2) k-space, (3) "trade-off triangle" and (4) fat suppression. This review is the first of five manuscripts in a minisymposium on pediatric MR. The authors' goal for this review is to aid in understanding the MR techniques described in the subsequent manuscripts on brain imaging and body imaging in this minisymposium.

  1. Law on the peaceful uses of nuclear energy: key concepts

    International Nuclear Information System (INIS)

    Pompignan, D. de

    2005-01-01

    The key concepts which ought to be included in legislation governing the peaceful uses of nuclear energy can be divided into two categories depending on whether they derive from the fundamental principles of nuclear law or reflect categories of general law. Their inclusion results in compliance with a shared obligation when they derive from a binding international instrument. It also permits the transposition into law of broader nuclear concepts and principles, and the more specific characteristics of a general nuclear law, which is to lay down priorities. When the resulting classification is tested in reality, we can see that it is difficult to measure the effectiveness of the two concept categories inasmuch as this depends not only on quantifiable and controllable legal elements but also on non-legal behavioural factors, an obvious example of which is safety culture. Once the difficulties of defining a legal framework for nuclear activities and selecting the key concepts to guide them are known, the inclusion of a concept in a general nuclear law is determined by national legal and ethical considerations. Thus, a general nuclear law should indicate the way in which the legal principles which reflect various prevailing ethical imperatives with regard to the environment, participation, and public interest, are applicable to the development of the peaceful uses of nuclear energy, having regard to the national specificities of each country and the particular nature of these activities. This means that there is a need to find original legal solutions reconciling the constraints of a specific law with the requirements of the ordinary law, i.e. the key concepts deriving from the principles of nuclear law. Given the possible reluctance of lawmakers to commit themselves for the future by formulating detailed provisions valid over the long term, it has been suggested that a code of good practice for the nuclear industry should be introduced which would go beyond the

  2. Sociocultural dimensions of tuberculosis: an overview of key concepts.

    Science.gov (United States)

    Mason, P H; Degeling, C; Denholm, J

    2015-10-01

    Biomedical innovations are unlikely to provide effective and ethical tuberculosis (TB) control measures without complementary social science research. However, a strong interest in interdisciplinary work is often undermined by differences in language and concepts specific to each disciplinary approach. Accordingly, biological and social scientists need to learn how to communicate with each other. This article will outline key concepts relating to TB from medical anthropology and health sociology. Distilling these concepts in an introductory framework is intended to make this material accessible to researchers in laboratory, clinical and fieldwork settings, as well as to encourage more social scientists to engage with TB research among target groups critical for successful programmatic interventions. For pedagogical purposes, the relevant concepts are grouped into three categories: 1) structures and settings, which includes overarching themes such as syndemics, local biologies, medicalisation, structural violence and surveillance; 2) practices and processes, encompassing gender, stigma, taboo, and victim blaming; and 3) experience and enculturation, which includes illness narratives, biographical disruption and dynamic nominalism. By helping to navigate this literature, we hope to foster more cross-disciplinary conversations between qualitative and quantitative researchers. TB, a quintessential social disease, will be controlled more effectively using a multistranded research approach.

  3. Statistical physics and thermodynamics an introduction to key concepts

    CERN Document Server

    Rau, Jochen

    2017-01-01

    Statistical physics and thermodynamics describe the behaviour of systems on the macroscopic scale. Their methods are applicable to a wide range of phenomena: from refrigerators to the interior of stars, from chemical reactions to magnetism. Indeed, of all physical laws, the laws of thermodynamics are perhaps the most universal. This text provides a concise yet thorough introduction to the key concepts which underlie statistical physics and thermodynamics. It begins with a review of classical probability theory and quantum theory, as well as a careful discussion of the notions of information and entropy, prior to embarking on the development of statistical physics proper. The crucial steps leading from the microscopic to the macroscopic domain are rendered transparent. In particular, the laws of thermodynamics are shown to emerge as natural consequences of the statistical framework. While the emphasis is on clarifying the basic concepts, the text also contains many applications and classroom-tested exercises,...

  4. Learning Grasp Affordance Densities

    DEFF Research Database (Denmark)

    Detry, Renaud; Kraft, Dirk; Kroemer, Oliver

    2011-01-01

    and relies on kernel density estimation to provide a continuous model. Grasp densities are learned and refined from exploration, by letting a robot “play” with an object in a sequence of graspand-drop actions: The robot uses visual cues to generate a set of grasp hypotheses; it then executes......We address the issue of learning and representing object grasp affordance models. We model grasp affordances with continuous probability density functions (grasp densities) which link object-relative grasp poses to their success probability. The underlying function representation is nonparametric...... these and records their outcomes. When a satisfactory number of grasp data is available, an importance-sampling algorithm turns these into a grasp density. We evaluate our method in a largely autonomous learning experiment run on three objects of distinct shapes. The experiment shows how learning increases success...

  5. Scale-Dependent Grasp

    OpenAIRE

    Kaneko, Makoto; Shirai, Tatsuya; Tsuji, Toshio

    2000-01-01

    This paper discusses the scale-dependent grasp.Suppose that a human approaches an object initially placed on atable and finally achieves an enveloping grasp. Under such initialand final conditions, he (or she) unconsciously changes the graspstrategy according to the size of objects, even though they havesimilar geometry. We call the grasp planning the scale-dependentgrasp. We find that grasp patterns are also changed according tothe surface friction and the geometry of cross section in additi...

  6. Key non-controversial concepts of population education.

    Science.gov (United States)

    Sikes, O J; Palacio, J; Kerr, B

    1993-03-01

    The important components of population education should focus on sexuality rather than sex education; content for inclusion depends upon whether the goal is population awareness or critical awareness. Population awareness is the better understanding of the nature, causes, and consequences of population changes experienced by a community, country, region. Critical awareness is the intent and ability to change the sociocultural or educational characteristics that influence fertility, mortality, and migration. 6 basic concepts with universal applicability are discussed, because if not handled properly, the topic become controversial. The concepts are linked to developing thinking or reasoning ability. The concepts are as follows: 1) respect for others, particularly those of the opposite sex; 2) development of self-esteem for both boys and girls; 3) the knowledge that planning is possible and desirable; 4) postponement of first pregnancy; 5) acceptance of responsibility for the consequences of behavior; and 6) the ability to recognize and withstand social pressure. When children learn respect for others, there is little likelihood that others will be harmed. Respect for girls and women is particularly important, and harmful stereotyping and their effects should be pointed out. The key is to develop healthy attitudes and values toward people, not just an intellectualization of gender issues. Self-esteem is used here to mean self-worth in the present and the future. Children can be helped to develop confidence, perseverance, and optimism. Children need to understand that carefully thought out decisions should precede a birth; fatalism and destiny is a choice. Postponing the first pregnancy can lead to economic, emotional, and physical benefits. Risk to the health of the mother and baby occurs during the teen years. The best time for pregnancy is between the ages of 20 and 30 years. A pregnancy in the teen years may have longterm consequences such as more pregnancy and

  7. The pan occupational paradigm: development and key concepts.

    Science.gov (United States)

    Hitch, Danielle; Pepin, Genevieve; Stagnitti, Karen

    2018-01-01

    Wilcock's Occupational Perspective of Health (OPH) aligns with the profession's re-discovery of its holistic, occupationally focused roots. Its dimensions of occupation-doing, being, becoming and belonging - resonate strongly with therapists on an intuitive, implicit level. However, its documented use in practice to date has been sparse, and several barriers to its implementation have been identified. The aim of this article is to present a renewal of the OPH - the Pan Occupational Paradigm (POP). Method of development: POP was developed using critical analysis, reflection and a comprehensive literature review. Each stage of development is described in detail, including the POP's inherent assumptions. Key concepts: POP retains the four dimensions of occupation, and shows their interdependent role within occupational entities (e.g. individuals, groups or communities). An entity can be approached by occupational therapy at any point and all the dimensions (either directly or indirectly) can be engaged. Occupational entities move along a continuum of wellbeing, and this movement can be in both positive and negative directions over a lifespan. POP is a distillation of occupational therapy's unique way of knowing about occupation and the promotion of wellbeing. It is put forward as an updated paradigm for occupational therapy in the 21st century.

  8. Teaching Abstract Concepts: Keys to the World of Ideas.

    Science.gov (United States)

    Flatley, Joannis K.; Gittinger, Dennis J.

    1990-01-01

    Specific teaching strategies to help hearing-impaired secondary students comprehend abstract concepts include (1) pinpointing facts and fallacies, (2) organizing information visually, (3) categorizing ideas, and (4) reinforcing new vocabulary and concepts. Figures provide examples of strategy applications. (DB)

  9. Grasping in Robotics

    CERN Document Server

    2013-01-01

    Grasping in Robotics contains original contributions in the field of grasping in robotics with a broad multidisciplinary approach. This gives the possibility of addressing all the major issues related to robotized grasping, including milestones in grasping through the centuries, mechanical design issues, control issues, modelling achievements and issues, formulations and software for simulation purposes, sensors and vision integration, applications in industrial field and non-conventional applications (including service robotics and agriculture).   The contributors to this book are experts in their own diverse and wide ranging fields. This multidisciplinary approach can help make Grasping in Robotics of interest to a very wide audience. In particular, it can be a useful reference book for researchers, students and users in the wide field of grasping in robotics from many different disciplines including mechanical design, hardware design, control design, user interfaces, modelling, simulation, sensors and hum...

  10. GRASP: A multitasking tether

    Directory of Open Access Journals (Sweden)

    Catherine eRabouille

    2016-01-01

    Full Text Available Originally identified as Golgi stacking factors in vitro, the Golgi reassembly stacking protein (GRASP family has been shown to act as membrane tethers with multiple cellular roles. As an update to previous comprehensive reviews of the GRASP family (Vinke et al., 2011 (Giuliani et al., 2011;Jarvela and Linstedt, 2012, we outline here the latest findings concerning their diverse roles. New insights into the mechanics of GRASP-mediated tethering come from recent crystal structures. The models of how GRASP65 and GRASP55 tether membranes relate directly to their role in Golgi ribbon formation in mammalian cells and the unlinking of the ribbon at the onset of mitosis. However, it is also clear that GRASPs act outside the Golgi with roles at the ER and ER exit sites (ERES. Furthermore, the proteins of this family display other roles upon cellular stress, especially in mediating unconventional secretion of both transmembrane proteins (Golgi bypass and cytoplasmic proteins (through secretory autophagosomes.

  11. Political economy of agrarian change: Some key concepts and questions

    Directory of Open Access Journals (Sweden)

    H Bernstein

    2017-12-01

    Full Text Available This paper draws on lectures given in recent years at the China Agricultural University, on author’s book Class Dynamics of Agrarian Change [1] and on a recent article [3]. The author supplied as few references as possible to very large literature in English on agrarian change both historical and contemporary; there is an ample bibliography in [1], which is expanded in [2-5]. The paper outlines in schematic fashion some key concepts in the political economy of agrarian change with special reference to capitalism historically and today; some key questions posed by the political economy of agrarian change, and how it seeks to investigate and answer them; two sets of more specific questions about agrarian transition to capitalism and agrarian change within capitalism (internal to the countryside, bringing in rural-urban interconnections, pointing towards the place of agriculture within larger ‘national’ economies, and concerning the character and effects of the capitalist world economy. With the aid of the last group of questions, the author discusses three themes, which they are deployed to investigate: the agrarian origins of capitalism, the distinction between farming and agriculture generated by capitalism, and the fate(s of peasant farmers in the modern world of capitalism. The author believes that one cannot conceive the emergence and functioning of agriculture in modern capitalism without the centrality and configurations of new sets of dynamics linking agriculture and industry, and the rural and urban, and the local, national and global. The three themes all feed into the fourth and final theme, that of investigating the fate(s of the peasantry in capitalism today, which resonates longstanding debates of the ‘disappearance’ or ‘persistence’ of the peasantry, albeit now in the conditions of contemporary ‘globalization’. The author does not deny some of the critique of the contemporary globalization, or at least its effects

  12. Organization culture and the marketing concept: diagnostic keys for hospitals.

    Science.gov (United States)

    Arnold, D R; Capella, L M; Sumrall, D A

    1987-03-01

    For successful adaptation to changing environmental conditions, hospital organizational cultures must incorporate the marketing concept to enhance flexibility and orientation toward the external environment. The authors propose procedures for diagnosing a hospital's culture and determining how well it has adopted and implemented the marketing concept.

  13. The concept of key success factors: Theory and method

    DEFF Research Database (Denmark)

    Grunert, Klaus G.; Ellegaard, Charlotte

    1992-01-01

    Executive summary: 1. The term key success factors can be used in four different ways: a) as a necessary ingre-dient in a management information system, b) as a unique characteristic of a company, c) as a heuristic tool for managers to sharpen their thinking, d) as a description of the major skills...... and resources required to be successful in a given market. We adopt the last view. 2. The actual key success factors on a market, and those key success factors perceived by decision-makers in companies operating in the market, will be different. A number of psychological mechanisms result in misperceptions...... or resource that a business can i in, which, on the market the business is operating on, explains a major part of the observable differences in perceived value and/or relative costs. 4. Key success factors differ from core skills and resources, which are prerequisites for being on a market, but do not explain...

  14. Key Concepts of Conservatism in Ecuador (1875-1900

    Directory of Open Access Journals (Sweden)

    Carlos Espinosa Fernández de Córdoba

    2015-01-01

    Full Text Available This study seeks to understand conservative political language in Ecuador during the last third of the 19th century as an expression of political modernity and as a discourse involving dialogue with liberal concepts. The conservative ideas of "Catholic freedom", "Catholic civilization" and "perfect society" are explored, and the reciprocal manner in which these concepts were defined relative to liberal notions is investigated. Using conceptual history, polysemantic political categories are analyzed in a context of struggle and in relation to the rise of modernity.

  15. Landscape practise and key concepts for landscape sustainability

    DEFF Research Database (Denmark)

    Brandt, Jesper; Christensen, Andreas Aagaard; Svenningsen, Stig Roar

    2013-01-01

    Conceptual frameworks which have seen man and nature as being an integrated whole were widespread before they became suppressed by developments within both capitalism and socialism. Therefore an idealistic use of such concepts in scientific work has often had limited practical value. At the same...... and relate it to an empirical study of sustainable tourism in eight protected areas and their regions in the Baltic. They are subject to large differences in human pressure. The political commitment to the related EU Natura 2000 networks has been taken as our point of departure for a more detailed analysis...... of accessibility and its related conflicts, and opportunities for a sustainable development of tourism in and around the protected areas. It is concluded that the concept of carrying capacity cannot meaningfully be used for sustainability studies at an abstract conceptual level, but proves its relevance through...

  16. The key to technical translation, v.1 concept specification

    CERN Document Server

    Hann, Michael

    1992-01-01

    This handbook for German/English/German technical translators at all levels from student to professional covers the root terminologies of the spectrum of scientific and engineering fields. The work is designed to give technical translators direct insight into the main error sources occurring in their profession, especially those resulting from a poor understanding of the subject matter and the usage of particular terms to designate different concepts in different branches of technology. The style is easy to read and suitable for nonnative English speakers and translators with no engineering ex

  17. Progress on DEMO blanket attachment concept with keys and pins

    International Nuclear Information System (INIS)

    Vizvary, Zsolt; Iglesias, Daniel; Cooper, David; Crowe, Robert; Riccardo, Valeria

    2015-01-01

    Highlights: • DEMO blanket attachment system with keys and pins (without using bolts). • Blanket segments are preloaded by progressively designed springs. • Blanket back plate flexibility has a major impact on spring design. • Mechanical analysis of other components indicates no unresolvable issues. • Thermal analysis indicates acceptable temperatures for the support system. - Abstract: The blanket attachment has to cope with gravity, thermal and electromagnetic loads, also it has to be installed and serviced by remote handling. Pre-stressed components suffer from stress relaxation in irradiated environments such as DEMO. To circumvent this problem pre-stressed component should be either avoided or shielded, and where possible keys and pins should be used. This strategy has been proposed for the DEMO multi-module segments (MMS). The blanket segments are held by two tapered keys each, designed to allow thermal expansions while providing contact with the vacuum vessel and to resist the poloidal and radial moments the latter being dominant at 9.1 MNm inboard and 15 MNm outboard. On the top of the blanket segment there is a pin which provides vertical support. At the bottom another vertical support has to lock them in position after installation and manage the pre-load on the segments. The pre-load is required to deal with the electromagnetic loads during disruption. This is provided by a set of springs, which require shielding as they are preloaded. These are sized to cope with the force (3 MN inboard, 1.4 MN outboard) due to halo currents and the toroidal moment which can reverse. Calculations show that the flexibility of the blanket segment itself plays a significant role in defining the required support system. The blanket segment acts as a preloaded spring and it has to be part of the attachment design as well.

  18. Learning Outcomes as a Key Concept in Policy Documents throughout Policy Changes

    Science.gov (United States)

    Prøitz, Tine Sophie

    2015-01-01

    Learning outcomes can be considered to be a key concept in a changing education policy landscape, enhancing aspects such as benchmarking and competition. Issues relating to concepts of performance have a long history of debate within the field of education. Today, the concept of learning outcomes has become central in education policy development,…

  19. Enhancing the tourist attraction visiting process with gamification: key concepts

    Directory of Open Access Journals (Sweden)

    Swacha Jakub

    2017-12-01

    Full Text Available The main purpose of this paper is to describe key gamification techniques that can be applied to enhance the tourist attraction visiting process. The paper is based on the methodology of design patterns; particularly it adopts the definition and classification schemes originally proposed and developed in the context of gamification of work to specify gamification techniques related to various aspects of the tourist attraction visiting process. The main result is the selection of twelve gamification techniques for enhancing the tourist attraction visiting process, four for each of the three phases of the visiting process (before, during and after the visit. The paper shows that gamification techniques can be applied to enhance the tourist attraction visiting process. Implementation of the proposed gamification techniques is supposed to both improve visitor experience and give the tourist attraction managers a tool for boosting interest in less popular exhibitions and events.

  20. Two key concepts of the society-climate change interface: vulnerability and adaptation

    International Nuclear Information System (INIS)

    Magnan, Alexandre

    2010-06-01

    Vulnerability and adaptation are two inseparable concepts, each being dependent on the other. Although they are extremely sensitive to the contextual specificities of particular areas, vulnerability reduction and adaptation strategies can only be developed at the interface between different spatial and temporal scales. This leads us to assert that faced with a common threat - climate change -, different types of vulnerability and adaptation exist. The aim of this text is to provide an overview of two concepts that can no longer be ignored in discussions on climate change: vulnerability and adaptation. These are two pillars for analysing both the potential impact of climate change on societies and regions, and also their ability to live with these consequences. We will begin by describing how the interdependence of these two concepts explains the position(s) of present and future societies in the face of climate change impacts. We will then show that they share certain determinants that may themselves provide an appropriate framework for analysis. Finally, we will insist on the fact that these two concepts nevertheless remain extremely difficult to grasp, as they require a multi-scalar and multi-temporal approach to regions, which also explains why they are a relevant response to the challenges posed by climate change. The conclusion will call for wider discussion, reiterating that since their nature is fundamentally linked to the diversity and specificities of regions and societies, we must accept the idea that faced with the same threat - climate change - there are different types of vulnerability and adaptation. (author)

  1. Ensuring quality in qualitative inquiry: using key concepts as guidelines

    Directory of Open Access Journals (Sweden)

    Debra Frances Campbell

    2013-09-01

    Full Text Available The field of qualitative scientific inquiry employs a fast-growing variety of approaches, whose traditions, procedures, and structures vary, depending on the type of study design and methodology (i.e., phenomenological, ethnographic, grounded theory, case study, action research, etc.. With the interpretive approach, researchers do not utilize the same measures of validity used in positivist approaches to scientific inquiry, since there is "...no one standard or accepted structure as one typically finds in quantitative research" (Creswell, 2007. With the absence of a single standard, how, then, is it possible for qualitative researchers to know whether or not their study was done with rigor, that it has validity, that it is ready to submit to their peers? The research literature is sprinkled with references to quality in qualitative inquiry, which helps to construe a study's validity. Markula (2008 suggests that we validate our study's findings by assuring readers that it was done "in the best possible way." While each research tradition has its own set of criteria for judging quality, we present here general concepts drawn from the literature. We hope this article will provide a framework from which qualitative researchers can judge their work before submitting it to their peers¸ one which will help ensure that their study was done "in the best possible way."

  2. Physical Activity and Obesity: Biomechanical and Physiological Key Concepts

    Directory of Open Access Journals (Sweden)

    Julie Nantel

    2011-01-01

    Full Text Available Overweight (OW and obesity (OB are often associated with low levels of physical activity. Physical activity is recommended to reduce excess body weight, prevent body weight regain, and decrease the subsequent risks of developing metabolic and orthopedic conditions. However, the impact of OW and OB on motor function and daily living activities must be taken into account. OW and OB are associated with musculoskeletal structure changes, decreased mobility, modification of the gait pattern, and changes in the absolute and relative energy expenditures for a given activity. While changes in the gait pattern have been reported at the ankle, knee, and hip, modifications at the knee level might be the most challenging for articular integrity. This review of the literature combines concepts and aims to provide insights into the prescription of physical activity for this population. Topics covered include the repercussions of OW and OB on biomechanical and physiological responses associated with the musculoskeletal system and daily physical activity. Special attention is given to the effect of OW and OB in youth during postural (standing and various locomotor (walking, running, and cycling activities.

  3. An Overview of Tourism Seasonality: Key Concepts and Policies

    Directory of Open Access Journals (Sweden)

    Rita Cannas

    2012-08-01

    Full Text Available Seasonality in tourism represents a key topic in academic literature. Since the first study of BarOn (1975 about tourism seasonality, this topic is still currently being tackled over decades by several authors, as well as by policy makers of the tourism sector. The purpose of the study[1], rather than representing an exhaustive and complete framework of a wide field of study such as seasonality in tourism, is to explore the main characteristics of this phenomenon (causes, impacts, spatiality and temporality, measurements and to focus the attention on policies and strategies in order to highlight how and in which ways tourism destinations can modify tourism seasonality’s feature. If the rather more common perspective adopted is that seasonality presents business challenges to a destination and to individual operators, it is a crucial aim of this literature review the attempt to point out the main features of these challenges and to provide a rational framework for the tourism seasonality researches.    [1] The paper is drawn from: Cannas, R. (2010 Public Policies for tourism seasonality from a territorial perspective. Cases study in Scotland and Sardinia, PhD thesis, University of Bologna, Department of Economics, unpublished.

  4. Communicating Culture: An Exploratory Study of the Key Concepts in Maori Culture on Maori Web Sites

    Directory of Open Access Journals (Sweden)

    Zlatko J Kovacic

    2001-01-01

    Full Text Available We examine how accurately the belief system or cultural concepts of Maori, the indigenous people of New Zealand, is reconstructed in the virtual world of the Internet. Nine Maori web sites were searched using a list of 44 key concepts in Maori culture. We registered how many pages within a particular web site contain each of the key concepts. These numbers were set up in a data matrix for further statistical analysis. The Multidimensional Scaling method was used to construct a spatial representation of Maori web sites in the space generated by the key concepts in Maori culture. Using the correlation coefficients between derived dimensions and the key concepts we interpreted three dimensions as General Cultural, Intra-tribe Dynamics and Educational. The position of each Maori web site in this space has been located and described.

  5. A tomada de consciência analisada a partir do conceito de divisão: um estudo de caso The grasp of consciousness analysed through the concept of division: a case study

    Directory of Open Access Journals (Sweden)

    Sandra Patrícia Ataíde Ferreira

    2003-01-01

    Full Text Available Objetivou-se ilustrar a tomada de consciência através do conceito de divisão. Uma criança do sexo masculino, com 6 anos e 4 meses, cursando alfabetização em escola particular de Recife, foi entrevistada e solicitada a representar um problema. Realizou-se uma análise qualitativa, observando-se 5 momentos de tomada de consciência: 1 ausência de consciência da totalidade dos elementos; 2 consideração da totalidade dos elementos, sem tomada de consciência do resto; 3 surgimento de conflito cognitivo como possibilitador da tomada de consciência das relações entre os termos; 4 resolução do conflito a partir de um esquema cognitivo já existente - ausência de tomada de consciência do resto; 5 representação do termo resto, sem tomada de consciência da relação deste com os demais. Os resultados mostraram a construção de graus diferenciados de tomada de consciência da divisão, propiciados pelas intervenções do examinador e pela presença de referentes no enunciado, sem o alcance da conceituação.This study aimed to illustrate the grasp of consciousness through the concept of division. A male child, aged 6 years and 4 months, learning the basics of the language at a private school in Recife, was interviewed and requested to represent a problem. A qualitative analysis was carried out observing 5 moments of grasp of consciousness: 1 the absence of consciousness of the totality of all the elements; 2 the consideration of the totality of all elements, without being conscious of the others; 3 the appearance of cognitive conflict as a means to enable the consciousness of the relationship between the terms; 4 resolution of the conflict by a pre-existing cognitive scheme - the absence of consciousness of the rest; 5 the representation of the term rest, without the consciousness of its relationship with the others. The results showed the building of different degrees of grasp of consciousness of division, enabled by the examiner

  6. Hand Grasping Synergies As Biometrics.

    Science.gov (United States)

    Patel, Vrajeshri; Thukral, Poojita; Burns, Martin K; Florescu, Ionut; Chandramouli, Rajarathnam; Vinjamuri, Ramana

    2017-01-01

    Recently, the need for more secure identity verification systems has driven researchers to explore other sources of biometrics. This includes iris patterns, palm print, hand geometry, facial recognition, and movement patterns (hand motion, gait, and eye movements). Identity verification systems may benefit from the complexity of human movement that integrates multiple levels of control (neural, muscular, and kinematic). Using principal component analysis, we extracted spatiotemporal hand synergies (movement synergies) from an object grasping dataset to explore their use as a potential biometric. These movement synergies are in the form of joint angular velocity profiles of 10 joints. We explored the effect of joint type, digit, number of objects, and grasp type. In its best configuration, movement synergies achieved an equal error rate of 8.19%. While movement synergies can be integrated into an identity verification system with motion capture ability, we also explored a camera-ready version of hand synergies-postural synergies. In this proof of concept system, postural synergies performed well, but only when specific postures were chosen. Based on these results, hand synergies show promise as a potential biometric that can be combined with other hand-based biometrics for improved security.

  7. Hand Grasping Synergies As Biometrics

    Directory of Open Access Journals (Sweden)

    Ramana Vinjamuri

    2017-05-01

    Full Text Available Recently, the need for more secure identity verification systems has driven researchers to explore other sources of biometrics. This includes iris patterns, palm print, hand geometry, facial recognition, and movement patterns (hand motion, gait, and eye movements. Identity verification systems may benefit from the complexity of human movement that integrates multiple levels of control (neural, muscular, and kinematic. Using principal component analysis, we extracted spatiotemporal hand synergies (movement synergies from an object grasping dataset to explore their use as a potential biometric. These movement synergies are in the form of joint angular velocity profiles of 10 joints. We explored the effect of joint type, digit, number of objects, and grasp type. In its best configuration, movement synergies achieved an equal error rate of 8.19%. While movement synergies can be integrated into an identity verification system with motion capture ability, we also explored a camera-ready version of hand synergies—postural synergies. In this proof of concept system, postural synergies performed well, but only when specific postures were chosen. Based on these results, hand synergies show promise as a potential biometric that can be combined with other hand-based biometrics for improved security.

  8. Felker's Five Keys to Self-Concept Enhancement: Secondary Classroom Research.

    Science.gov (United States)

    Bernhoft, Franklin O.

    A study incorporated Donald Felker's 5 Keys to Self-Concept Enhancement in 20 minutes of timed writing weekly or bi-weekly for three months using the Coopersmith Adult Form as pre-post measure. Felker's 5 Keys are: (1) adults, praise yourselves; (2) help children evaluate realistically; (3) teach children to set realistic goals; (4) teach children…

  9. Grasping without sight: insights from the congenitally blind.

    Directory of Open Access Journals (Sweden)

    Kayla D Stone

    Full Text Available We reach for and grasp different sized objects numerous times per day. Most of these movements are visually-guided, but some are guided by the sense of touch (i.e. haptically-guided, such as reaching for your keys in a bag, or for an object in a dark room. A marked right-hand preference has been reported during visually-guided grasping, particularly for small objects. However, little is known about hand preference for haptically-guided grasping. Recently, a study has shown a reduction in right-hand use in blindfolded individuals, and an absence of hand preference if grasping was preceded by a short haptic experience. These results suggest that vision plays a major role in hand preference for grasping. If this were the case, then one might expect congenitally blind (CB individuals, who have never had a visual experience, to exhibit no hand preference. Two novel findings emerge from the current study: first, the results showed that contrary to our expectation, CB individuals used their right hand during haptically-guided grasping to the same extent as visually-unimpaired (VU individuals did during visually-guided grasping. And second, object size affected hand use in an opposite manner for haptically- versus visually-guided grasping. Big objects were more often picked up with the right hand during haptically-guided, but less often during visually-guided grasping. This result highlights the different demands that object features pose on the two sensory systems. Overall the results demonstrate that hand preference for grasping is independent of visual experience, and they suggest a left-hemisphere specialization for the control of grasping that goes beyond sensory modality.

  10. Stress, deformation, conservation, and rheology: a survey of key concepts in continuum mechanics

    Science.gov (United States)

    Major, J.J.

    2013-01-01

    This chapter provides a brief survey of key concepts in continuum mechanics. It focuses on the fundamental physical concepts that underlie derivations of the mathematical formulations of stress, strain, hydraulic head, pore-fluid pressure, and conservation equations. It then shows how stresses are linked to strain and rates of distortion through some special cases of idealized material behaviors. The goal is to equip the reader with a physical understanding of key mathematical formulations that anchor continuum mechanics in order to better understand theoretical studies published in geomorphology.

  11. Key Concept Identification: A Comprehensive Analysis of Frequency and Topical Graph-Based Approaches

    Directory of Open Access Journals (Sweden)

    Muhammad Aman

    2018-05-01

    Full Text Available Automatic key concept extraction from text is the main challenging task in information extraction, information retrieval and digital libraries, ontology learning, and text analysis. The statistical frequency and topical graph-based ranking are the two kinds of potentially powerful and leading unsupervised approaches in this area, devised to address the problem. To utilize the potential of these approaches and improve key concept identification, a comprehensive performance analysis of these approaches on datasets from different domains is needed. The objective of the study presented in this paper is to perform a comprehensive empirical analysis of selected frequency and topical graph-based algorithms for key concept extraction on three different datasets, to identify the major sources of error in these approaches. For experimental analysis, we have selected TF-IDF, KP-Miner and TopicRank. Three major sources of error, i.e., frequency errors, syntactical errors and semantical errors, and the factors that contribute to these errors are identified. Analysis of the results reveals that performance of the selected approaches is significantly degraded by these errors. These findings can help us develop an intelligent solution for key concept extraction in the future.

  12. Translation and Its Discontents: Key Concepts in English and German History Education

    Science.gov (United States)

    Seixas, Peter

    2016-01-01

    Key terms and concepts are crucial tools in teaching and learning in the disciplines. Different linguistic traditions approach such tools in diverse ways. This paper offers an initial contribution by a monolingual Anglophone history educator in dialogue with German history educators. It presents three different scenarios for the potential of…

  13. Key concepts in MR spectroscopy and practical approaches to gaining biochemical information in children

    Energy Technology Data Exchange (ETDEWEB)

    Astrakas, Loukas G. [University of Ioannina, Medical Physics, Medical School, P.O. Box 1186, Ioannina (Greece); Argyropoulou, Maria I. [University of Ioannina, Radiology, Medical School, Ioannina (Greece)

    2016-06-15

    Magnetic resonance spectroscopy (MRS) provides independent biochemical information and has become an invaluable adjunct to MRI and other imaging modalities. This review introduces key concepts and presents basic methodological steps regarding the acquisition and the interpretation of proton MRS. We review major brain metabolites and discuss MRS dependence on age, location, echo time and field strength. (orig.)

  14. Seeking convergence on the key concepts in "no net loss" policy

    DEFF Research Database (Denmark)

    Bull, Joseph William; Gordon, Ascelin; Watson, James E.M.

    2016-01-01

    . The recommendations made in this article, on improving clarity and supporting convergence on key no net loss (NNL) concepts, should help eliminate ambiguity in policy documentation. This is crucial if policymakers are to design robust policies that are (i) transparent, (ii) translatable into practice in a consistent......Biodiversity conservation policies incorporating a no net loss (NNL) principle are being implemented in many countries. However, there are linguistic and conceptual inconsistencies in the use of terms underlying these NNL policies. We identify inconsistencies that emerge in the usage of eight key......, reduce ambiguity and improve clarity in communication and policy documentation. However, we also warn of the challenges in achieving convergence, especially given the linguistic inconsistencies in several of these key concepts among countries in which NNL policies are employed. Policy implications...

  15. The Double Contingency as a Key to Redifine the Concept of Social Order

    Directory of Open Access Journals (Sweden)

    Juan Pablo Gonnet

    2017-10-01

    Full Text Available The double contingency represents a key concept in Niklas Luhmann’s theory of social systems by giving rise to a new treatment of the problem of social order. From its consideration, it is possible to explain social order without blocking the contingency of both individual action and social structures. However, something that has remained out of discussion is precisely what concept of “order” is implied in the author's proposal. In principle, we identify a frequently assumed conception of order in social theory, which is related to the limitation (or conditioning of individual action/communication/selection. The aim of this paper is to demonstrate that the double contingency would also allow us to problematize and redefine this conception.

  16. Minimal Reducts with Grasp

    Directory of Open Access Journals (Sweden)

    Iris Iddaly Mendez Gurrola

    2011-03-01

    Full Text Available The proper detection of patient level of dementia is important to offer the suitable treatment. The diagnosis is based on certain criteria, reflected in the clinical examinations. From these examinations emerge the limitations and the degree in which each patient is in. In order to reduce the total of limitations to be evaluated, we used the rough set theory, this theory has been applied in areas of the artificial intelligence such as decision analysis, expert systems, knowledge discovery, classification with multiple attributes. In our case this theory is applied to find the minimal limitations set or reduct that generate the same classification that considering all the limitations, to fulfill this purpose we development an algorithm GRASP (Greedy Randomized Adaptive Search Procedure.

  17. Continuum robots and underactuated grasping

    Directory of Open Access Journals (Sweden)

    N. Giri

    2011-02-01

    Full Text Available We discuss the capabilities of continuum (continuous backbone robot structures in the performance of under-actuated grasping. Continuum robots offer the potential of robust grasps over a wide variety of object classes, due to their ability to adapt their shape to interact with the environment via non-local continuum contact conditions. Furthermore, this capability can be achieved with simple, low degree of freedom hardware. However, there are practical issues which currently limit the application of continuum robots to grasping. We discuss these issues and illustrate via an experimental continuum grasping case study.

    This paper was presented at the IFToMM/ASME International Workshop on Underactuated Grasping (UG2010, 19 August 2010, Montréal, Canada.

  18. Fire regime: history and definition of a key concept in disturbance ecology.

    Science.gov (United States)

    Krebs, Patrik; Pezzatti, Gianni B; Mazzoleni, Stefano; Talbot, Lee M; Conedera, Marco

    2010-06-01

    "Fire regime" has become, in recent decades, a key concept in many scientific domains. In spite of its wide spread use, the concept still lacks a clear and wide established definition. Many believe that it was first discussed in a famous report on national park management in the United States, and that it may be simply defined as a selection of a few measurable parameters that summarize the fire occurrence patterns in an area. This view has been uncritically perpetuated in the scientific community in the last decades. In this paper we attempt a historical reconstruction of the origin, the evolution and the current meaning of "fire regime" as a concept. Its roots go back to the 19th century in France and to the first half of the 20th century in French African colonies. The "fire regime" concept took time to evolve and pass from French into English usage and thus to the whole scientific community. This coincided with a paradigm shift in the early 1960s in the United States, where a favourable cultural, social and scientific climate led to the natural role of fires as a major disturbance in ecosystem dynamics becoming fully acknowledged. Today the concept of "fire regime" refers to a collection of several fire-related parameters that may be organized, assembled and used in different ways according to the needs of the users. A structure for the most relevant categories of parameters is proposed, aiming to contribute to a unified concept of "fire regime" that can reconcile the physical nature of fire with the socio-ecological context within which it occurs.

  19. Ecological thresholds: The key to successful enviromental management or an important concept with no practical application?

    Science.gov (United States)

    Groffman, P.M.; Baron, Jill S.; Blett, T.; Gold, A.J.; Goodman, I.; Gunderson, L.H.; Levinson, B.M.; Palmer, Margaret A.; Paerl, H.W.; Peterson, G.D.; Poff, N.L.; Rejeski, D.W.; Reynolds, J.F.; Turner, M.G.; Weathers, K.C.; Wiens, J.

    2006-01-01

    An ecological threshold is the point at which there is an abrupt change in an ecosystem quality, property or phenomenon, or where small changes in an environmental driver produce large responses in the ecosystem. Analysis of thresholds is complicated by nonlinear dynamics and by multiple factor controls that operate at diverse spatial and temporal scales. These complexities have challenged the use and utility of threshold concepts in environmental management despite great concern about preventing dramatic state changes in valued ecosystems, the need for determining critical pollutant loads and the ubiquity of other threshold-based environmental problems. In this paper we define the scope of the thresholds concept in ecological science and discuss methods for identifying and investigating thresholds using a variety of examples from terrestrial and aquatic environments, at ecosystem, landscape and regional scales. We end with a discussion of key research needs in this area.

  20. Grasp force sensor for robotic hands

    Science.gov (United States)

    Scheinman, Victor D. (Inventor); Bejczy, Antal K. (Inventor); Primus, Howard C. (Inventor)

    1989-01-01

    A grasp force sensor for robotic hands is disclosed. A flexible block is located in the base of each claw through which the grasp force is exerted. The block yields minute parallelogram deflection when the claws are subjected to grasping forces. A parallelogram deflection closely resembles pure translational deflection, whereby the claws remain in substantial alignment with each other during grasping. Strain gauge transducers supply signals which provide precise knowledge of and control over grasp forces.

  1. Artist concept illustrating key events on day by day basis during Apollo 9

    Science.gov (United States)

    1969-01-01

    Artist concept illustrating key events on day by day basis during Apollo 9 mission. First photograph illustrates activities on the first day of the mission, including flight crew preparation, orbital insertion, 103 north mile orbit, separations, docking and docked Service Propulsion System Burn (19792); Second day events include landmark tracking, pitch maneuver, yaw-roll maneuver, and high apogee orbits (19793); Third day events include crew transfer and Lunar Module system evaluation (19794); Fourth day events include use of camera, day-night extravehicular activity, use of golden slippers, and television over Texas and Louisiana (19795); Fifth day events include vehicles undocked, Lunar Module burns for rendezvous, maximum separation, ascent propulsion system burn, formation flying and docking, and Lunar Module jettison ascent burn (19796); Sixth thru ninth day events include service propulsion system burns and landmark sightings, photograph special tests (19797); Tenth day events i

  2. Adapting planning and scheduling concepts to an engineering perspective: Key issues and successful techniques

    International Nuclear Information System (INIS)

    Finnegan, J.M.

    1986-01-01

    Traditional approaches to engineering planning are slanted toward the formats and interests of downstream implementation, and do not always consider the form and criticality of the front-end engineering development process. These processes and scopes are less defined and more subjective than most construction and operations tasks, and require flexible scheduling methods. This paper discusses the characteristics and requirement of engineering schedules, presents concepts for approaching planning in this field, and illustrates simple methods for developing and analyzing engineering plans, and evaluating schedule performance. Engineering plans are structured into a schedule hierarchy which delineates appropriate control and responsibilities, and is governed by key evaluation and decision milestones. Schedule risk analysis considers the uncertainty of engineering tasks, and critical resource constraints. Methods to evaluate schedule performance recognize that engineers and managers are responsible for adequate planning and forecasting, and quality decisions, even if they cannot control all factors influencing schedule results

  3. Tissue perfusion as a key underlying concept of pressure ulcer development and treatment.

    Science.gov (United States)

    Wywialowski, E F

    1999-03-01

    The purpose of this article is to refine and advance the theory that tissue perfusion is the key concept in the development and delayed healing of pressure ulcers. The person likely to have (be at risk for) pressure ulcers is at greater risk for inadequate tissue perfusion generally and specifically at pressure points. Accordingly, the tissue perfusion theory of pressure ulcer development states that the factors that contribute to inadequate tissue perfusion should be used to predict (identify risk factors for) pressure ulcer development and delayed healing. Factors influencing a person's adequacy of tissue perfusion need to be assessed to identify risk for pressure ulcers. In addition, adequate tissue perfusion needs to be maintained to provide for healing of such wounds. Current beliefs about the causes and prevention of pressure ulcers are described. Physiologic components of the tissue perfusion theory are discussed: cellular exchange of nutrients and wastes, autoregulation of blood flow at the cellular level, and regulatory mechanisms that affect tissue perfusion when it is significantly compromised. The North American Nursing Diagnosis Association (NANDA) framework is used to classify or group examples of common pathophysiologic, treatment-related, situational, and maturational factors. Implications for research, practice, and education also are discussed.

  4. Will Quantitative Proteomics Redefine Some of the Key Concepts in Skeletal Muscle Physiology?

    Science.gov (United States)

    Gizak, Agnieszka; Rakus, Dariusz

    2016-01-11

    Molecular and cellular biology methodology is traditionally based on the reasoning called "the mechanistic explanation". In practice, this means identifying and selecting correlations between biological processes which result from our manipulation of a biological system. In theory, a successful application of this approach requires precise knowledge about all parameters of a studied system. However, in practice, due to the systems' complexity, this requirement is rarely, if ever, accomplished. Typically, it is limited to a quantitative or semi-quantitative measurements of selected parameters (e.g., concentrations of some metabolites), and a qualitative or semi-quantitative description of expression/post-translational modifications changes within selected proteins. A quantitative proteomics approach gives a possibility of quantitative characterization of the entire proteome of a biological system, in the context of the titer of proteins as well as their post-translational modifications. This enables not only more accurate testing of novel hypotheses but also provides tools that can be used to verify some of the most fundamental dogmas of modern biology. In this short review, we discuss some of the consequences of using quantitative proteomics to verify several key concepts in skeletal muscle physiology.

  5. Will Quantitative Proteomics Redefine Some of the Key Concepts in Skeletal Muscle Physiology?

    Directory of Open Access Journals (Sweden)

    Agnieszka Gizak

    2016-01-01

    Full Text Available Molecular and cellular biology methodology is traditionally based on the reasoning called “the mechanistic explanation”. In practice, this means identifying and selecting correlations between biological processes which result from our manipulation of a biological system. In theory, a successful application of this approach requires precise knowledge about all parameters of a studied system. However, in practice, due to the systems’ complexity, this requirement is rarely, if ever, accomplished. Typically, it is limited to a quantitative or semi-quantitative measurements of selected parameters (e.g., concentrations of some metabolites, and a qualitative or semi-quantitative description of expression/post-translational modifications changes within selected proteins. A quantitative proteomics approach gives a possibility of quantitative characterization of the entire proteome of a biological system, in the context of the titer of proteins as well as their post-translational modifications. This enables not only more accurate testing of novel hypotheses but also provides tools that can be used to verify some of the most fundamental dogmas of modern biology. In this short review, we discuss some of the consequences of using quantitative proteomics to verify several key concepts in skeletal muscle physiology.

  6. Key Concepts in Education: Critical Issues beyond Definition and Discursive Practices

    Directory of Open Access Journals (Sweden)

    Theo Hug

    2013-11-01

    Full Text Available Along with the processes of digitization, medialization and the globalization of communications and lifeworlds, new topics, subject matters, conceptualizations and methods have been deve­loped in educational research and practice. On the one hand, from a diachronic perspective we can notice how new aspects of education (Bildung, upbringing (Erziehung, learning and communication have been addressed. On the other hand, from a synchronic perspective we can see a simultaneity of the non-simultaneous in terms of understandings, approaches, methodologies and forms of mediation and collaboration. Although more and more open initiatives and open educational resources (OER, as well as international collaborations and transnational intellectual networks, are being brought forward, epistemological aspects about using different key concepts are widely underestimated. The paper starts with: (1 an outline of selected understandings of education and literacy, followed by (2 a discussion of critical epistemological aspects by way of contrasting and correlating conceptual dimensions. Lastly, the contribution aims at (3 a sketch of polylogical design principles for educational knowledge organization.

  7. Public health ethics: key concepts and issues in policy and practice

    National Research Council Canada - National Science Library

    Dawson, Angus

    2011-01-01

    .... Topics covered include the nature of public health ethics, the concepts of disease and prevention, risk and precaution, health inequalities and justice, screening, vaccination and disease control...

  8. Virtuality as a key concept in the study of globalisation : aspects of the symbolic transformation of contemporary Africa

    NARCIS (Netherlands)

    Binsbergen, van W.M.J.

    1997-01-01

    The author concentrates on virtuality, which he has come to regard as one of the key concepts for characterizing and understanding the forms of globalization in Africa. Chapters 1 and 2 define virtuality and globalization and provisionally indicate their theoretical relationship. The problematic

  9. A Comparison of Key Concepts in Data Analytics and Data Science

    Science.gov (United States)

    McMaster, Kirby; Rague, Brian; Wolthuis, Stuart L.; Sambasivam, Samuel

    2018-01-01

    This research study provides an examination of the relatively new fields of Data Analytics and Data Science. We compare word rates in Data Analytics and Data Science documents to determine which concepts are mentioned most often. The most frequent concept in both fields is "data." The word rate for "data" is more than twice the…

  10. Assessing Children's Understanding of Length Measurement: A Focus on Three Key Concepts

    Science.gov (United States)

    Bush, Heidi

    2009-01-01

    In this article, the author presents three different tasks that can be used to assess students' understanding of the concept of length. Three important measurement concepts for students to understand are transitive reasoning, use of identical units, and iteration. In any teaching and learning process it is important to acknowledge students'…

  11. Connecting the Dots: A Discussion on Key Concepts in Contemporary Entrepreneurship Education

    Science.gov (United States)

    Hägg, Gustav; Kurczewska, Agnieszka

    2016-01-01

    Purpose: The purpose of this paper is to justify, elaborate and elucidate the concepts of action, experience and reflection, and how they are intertwined when discussing contemporary entrepreneurship education. These concepts have been given a meaning in entrepreneurship education, but have not been discussed in-depth, and by that have been…

  12. Grasping with mechanical intelligence. M.S. Thesis

    Science.gov (United States)

    Ulrich, Nathan Thatcher

    1988-01-01

    Many robotic hands have been designed and a number have been built. Because of the difficulty of controlling and using complex hands, which usually have nine or more degrees of freedom, the simple one- or two-degree-of-freedom gripper is still the most common robotic end effector. A new category of device is presented: a medium-complexity end effector. With three to five degrees of freedom, such a tool is much easier to control and use, as well as more economical, compact and lightweight than complex hands. In order to increase the versatility, it was necessary to identify grasping primitives and to implement them in the mechanism. In addition, power and enveloping grasps are stressed over fingertip and precision grasps. The design is based upon analysis of object apprehension types, requisite characteristics for active sensing, and a determination of necessary environmental interactions. Contained are the general concepts necessary to the design of a medium-complexity end effector, an analysis of typical performance, and a computer simulation of a grasp planning algorithm specific to this type of mechanism. Finally, some details concerning the UPenn Hand-a tool designed for the research laboratory-are presented.

  13. A Biologically Inspired Learning to Grasp System

    Science.gov (United States)

    2001-10-25

    possible extensive discussions of data on the premotor cortex and monkey grasping circuit with Giacomo Rizzolatti , Vittorio Gallese, to whom we express...premotor specialisation for the different types of grasps that Rizzolatti group [3] has found be formed at this age yet. Infants will need to...our gratitude. REFERENCES [1] M. Jeannerod, M.A. Arbib, G. Rizzolatti , H. Sakata, “Grasping objects: the cortical mechanisms of visuomotor

  14. Using the key success factor concept in competitor intelligence and benchmarking

    DEFF Research Database (Denmark)

    Bisp, Søren; Sørensen, Elin; Grunert, Klaus G.

    1997-01-01

    A key success factor is regarded as a skill or a resource that a business can invest in, which explains a major part of the observable differences in perceived value of the offer and/or relative costs of bringing that offer to the marketplace. Key success factors are potentially useful in structu......A key success factor is regarded as a skill or a resource that a business can invest in, which explains a major part of the observable differences in perceived value of the offer and/or relative costs of bringing that offer to the marketplace. Key success factors are potentially useful...... in structuring the generation of market intelligence in competitor analysis and benchmarking. To this end, a method was developed, based on a reverse laddering procedure, which elicits decision-makers' subjec causal maps. When aggregated, these maps can be used to derive competitor analysis systems. The paper...

  15. Secondary Traumatization in Psychiatric Mental Health Nurses: Validation of Five Key Concepts.

    Science.gov (United States)

    Hubbard, Grace B; Beeber, Linda; Eves, Erin

    2017-04-01

    The purpose of this study was to validate five concepts central to secondary traumatization (ST) using narratives of psychiatric mental health advanced practice nurses. The study was designed as a directed content analysis of narrative notes (N-30). Consistency was found between narrative notes and the concepts. This study revealed that exposure and vulnerability precede empathic engagement, reaction, and alteration/transformation. The bidirectional outcome of alteration/transformation suggested that conditions leading to ST could have a positive outcome. Failure to recognize symptoms of ST and provide reflective supervision may compromise the nurse's ability to maintain a work-life balance and provide quality patient care. © 2015 Wiley Periodicals, Inc.

  16. Density functional approach to the many-body problem : Key concepts and exact functionals

    NARCIS (Netherlands)

    van Leeuwen, Robert

    2003-01-01

    We give an overview of the fundamental concepts of density functional theory. We give a careful discussion of the several density functionals and their differentiability properties. We show that for nondegenerate ground states we can calculate the necessary functional derivatives by means of linear

  17. Visual Descriptor Learning for Predicting Grasping Affordances

    DEFF Research Database (Denmark)

    Thomsen, Mikkel Tang

    2016-01-01

    by the task of grasping unknown objects given visual sensor information. The contributions from this thesis stem from three works that all relate to the task of grasping unknown objects but with particular focus on the visual representation part of the problem. First an investigation of a visual feature space...... consisting of surface features was performed. Dimensions in the visual space were varied and the effects were evaluated with the task of grasping unknown object. The evaluation was performed using a novel probabilistic grasp prediction approach based on neighbourhood analysis. The resulting success......-rates for predicting grasps were between 75% and 90% depending on the object class. The investigations also provided insights into the importance of selecting a proper visual feature space when utilising it for predicting affordances. As a consequence of the gained insights, a semi-local surface feature, the Sliced...

  18. Refining Grasp Affordance Models by Experience

    DEFF Research Database (Denmark)

    Detry, Renaud; Kraft, Dirk; Buch, Anders Glent

    2010-01-01

    We present a method for learning object grasp affordance models in 3D from experience, and demonstrate its applicability through extensive testing and evaluation on a realistic and largely autonomous platform. Grasp affordance refers here to relative object-gripper configurations that yield stable...... with a visual model of the object they characterize. We explore a batch-oriented, experience-based learning paradigm where grasps sampled randomly from a density are performed, and an importance-sampling algorithm learns a refined density from the outcomes of these experiences. The first such learning cycle...... is bootstrapped with a grasp density formed from visual cues. We show that the robot effectively applies its experience by downweighting poor grasp solutions, which results in increased success rates at subsequent learning cycles. We also present success rates in a practical scenario where a robot needs...

  19. Grasp Algorithms For Optotactile Robotic Sample Acquisition, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Robotic sample acquisition is basically grasping. Multi-finger robot sample grasping devices are controlled to securely pick up samples. While optimal grasps for...

  20. Key Concepts of Real Estate Market Analysis and Valuation with Specific Application to Residential Apartment Investments.

    Science.gov (United States)

    1986-01-01

    but is intended to I r Ii m provide a basic understanding of essentilal real estate I investment concepts. I l! I I 11 I I I ! I I I~i lllm m I...3,100 Utilities - Electric 5,000 Utilities - Water 15,000 Utilities - Gas/ Oil 1,200 Total Expenses $137,700 [ Net Operating Income $273,343 59 Figure

  1. The need to disentangle key concepts from ecosystem-approach jargon.

    Science.gov (United States)

    Waylen, K A; Hastings, E J; Banks, E A; Holstead, K L; Irvine, R J; Blackstock, K L

    2014-10-01

    The ecosystem approach--as endorsed by the Convention on Biological Diversity (CDB) in 2000-is a strategy for holistic, sustainable, and equitable natural resource management, to be implemented via the 12 Malawi Principles. These principles describe the need to manage nature in terms of dynamic ecosystems, while fully engaging with local peoples. It is an ambitious concept. Today, the term is common throughout the research and policy literature on environmental management. However, multiple meanings have been attached to the term, resulting in confusion. We reviewed references to the ecosystem approach from 1957 to 2012 and identified 3 primary uses: as an alternative to ecosystem management or ecosystem-based management; in reference to an integrated and equitable approach to resource management as per the CBD; and as a term signifying a focus on understanding and valuing ecosystem services. Although uses of this term and its variants may overlap in meaning, typically, they do not entirely reflect the ethos of the ecosystem approach as defined by the CBD. For example, there is presently an increasing emphasis on ecosystem services, but focusing on these alone does not promote decentralization of management or use of all forms of knowledge, both of which are integral to the CBD's concept. We highlight that the Malawi Principles are at risk of being forgotten. To better understand these principles, more effort to implement them is required. Such efforts should be evaluated, ideally with comparative approaches, before allowing the CBD's concept of holistic and socially engaged management to be abandoned or superseded. It is possible that attempts to implement all 12 principles together will face many challenges, but they may also offer a unique way to promote holistic and equitable governance of natural resources. Therefore, we believe that the CBD's concept of the ecosystem approach demands more attention. © 2014 Society for Conservation Biology.

  2. Understanding Value as a Key Concept in Sustaining the Perioperative Nursing Workforce.

    Science.gov (United States)

    Kapaale, Chaluza C

    2018-03-01

    Perioperative nursing is faced with a staffing crisis attributed in part to minimal numbers of newly graduated nurses choosing a career in this specialty. This article analyzes and applies the concept of value to explore how to maintain an adequate perioperative nursing workforce; recruit newly graduated nurses; and encourage career professional, nurse educator, and student collaboration to generate meaningful value for perioperative nursing. This analysis revealed that value co-creation for perioperative nursing could lead to newly graduated nurses increasingly choosing perioperative nursing as a career, and enjoying satisfying perioperative nursing careers while providing high-quality patient care. © AORN, Inc, 2018.

  3. Probing the reaching-grasping network in humans through multivoxel pattern decoding.

    Science.gov (United States)

    Di Bono, Maria Grazia; Begliomini, Chiara; Castiello, Umberto; Zorzi, Marco

    2015-11-01

    The quest for a putative human homolog of the reaching-grasping network identified in monkeys has been the focus of many neuropsychological and neuroimaging studies in recent years. These studies have shown that the network underlying reaching-only and reach-to-grasp movements includes the superior parieto-occipital cortex (SPOC), the anterior part of the human intraparietal sulcus (hAIP), the ventral and the dorsal portion of the premotor cortex, and the primary motor cortex (M1). Recent evidence for a wider frontoparietal network coding for different aspects of reaching-only and reach-to-grasp actions calls for a more fine-grained assessment of the reaching-grasping network in humans by exploiting pattern decoding methods (multivoxel pattern analysis--MVPA). Here, we used MPVA on functional magnetic resonance imaging (fMRI) data to assess whether regions of the frontoparietal network discriminate between reaching-only and reach-to-grasp actions, natural and constrained grasping, different grasp types, and object sizes. Participants were required to perform either reaching-only movements or two reach-to-grasp types (precision or whole hand grasp) upon spherical objects of different sizes. Multivoxel pattern analysis highlighted that, independently from the object size, all the selected regions of both hemispheres contribute in coding for grasp type, with the exception of SPOC and the right hAIP. Consistent with recent neurophysiological findings on monkeys, there was no evidence for a clear-cut distinction between a dorsomedial and a dorsolateral pathway that would be specialized for reaching-only and reach-to-grasp actions, respectively. Nevertheless, the comparison of decoding accuracy across brain areas highlighted their different contributions to reaching-only and grasping actions. Altogether, our findings enrich the current knowledge regarding the functional role of key brain areas involved in the cortical control of reaching-only and reach-to-grasp actions

  4. Interlimb Transfer of Grasp Orientation is Asymmetrical

    Directory of Open Access Journals (Sweden)

    Victor Frak

    2006-01-01

    Full Text Available One the most fundamental aspects of the human motor system is the hemispheric asymmetry seen in behavioral specialization. Hemispheric dominance can be inferred by a contralateral hand preference in grasping. Few studies have considered grasp orientation in the context of manual lateralization and none has looked at grasp orientation with natural prehension. Thirty right-handed adults performed precision grasps of a cylinder using the thumb and index fingers, and the opposition axis (OA was defined as the line connecting these two contact points on the cylinder. Subjects made ten consecutive grasps with one hand (primary hand movements followed by ten grasps with the other hand (trailing movements. Differences between primary and trailing grasps revealed that each hemisphere is capable of programming the orientation of the OA and that primary movements with the right hand significantly influenced OA orientation of the trailing left hand. These results extend the hemispheric dominance of the left hemisphere to the final positions of fingers during prehension.

  5. Experiments in robotic sensorimotor control during grasp

    International Nuclear Information System (INIS)

    Stansfield, S.A.

    1993-01-01

    A series of experiments is presented, using a robot manipulator, which attempt to reproduce human sensorimotor control during grasping. The work utilizes a multifingered, dexterous robot hand equipped with a fingertip force sensor to explore dynamic grasp force adjustment during manipulation. The work is primarily concerned with the relationship between the weight of an object and the grasp force required to lift it. Too weak a grasp is unstable and the object will slip from the hand. Too strong a grasp may damage the object and/or the manipulator. An algorithm is presented which reproduces observed human behavior during grasp-and-lift tasks. The algorithm uses tactile information from the sensor to dynamically adjust the grasp force during lift. It is assumed that there is no a priori knowledge about the object to be manipulated. The effects of different arm/hand postures and object surfaces is explored. Finally, the use of sensory data to detect unexpected object motion and to signal transitions between manipulation phases--with the coincident triggering of new motor programs--is investigated

  6. “THE UNDERTAKING” AND “THE RELEVANT MARKET”: KEY CONCEPTS IN THE ANALYSIS OF ANTICOMPETITIVE PRACTICES

    Directory of Open Access Journals (Sweden)

    CRISTINA CUCU

    2012-05-01

    Full Text Available The desire to maintain themselves on a particular market, at a higher level of profitability or at a reasonable level at least, can lead the undertakings to adopt an anticompetitive behaviour more easily. This may result from either the existence of anticompetitive agreements and concerted practices, or the tendency to abuse its dominant position which the undertaking has on a certain market. “The undertaking” and “the relevant market” are the key concepts in the analysis of anticompetitive practices. The active subject of anticompetitive practices is “the undertaking”. This concept has a particular significance in the competition law, different from the common law. Competition rules apply to the conduct of undertakings and associations of undertakings so that the concept of undertaking makes it possible to determine the categories of actors to which the competition rules apply. However, the term undertaking is nowhere defined in the EU Treaties; as such, the concept has generated a complex body of jurisprudence."The market" is a term with pronounced economic resonances; synthetically, the market is the place where supply meets demand. In the context of the competition law, "the market" means "relevant market". The relevant market is the market of product/service in terms of demand and supply, and then superimposed on the geographic market.The analysis of these key concepts necessarily entails the conceptual delimitation of the notions. On this purpose, the relevant legal provisions will be identified in the Romanian and EU law, together with the decisions of the European Court of Justice in this matter.

  7. The Key Conceptions of Social Security: the International Practice and Ukraine

    Directory of Open Access Journals (Sweden)

    Dluhopolska Tetiana I.

    2017-02-01

    Full Text Available The world-wide globalization processes and the political-military conflicts have exacerbated the problem of social security of the people of various world countries, which is usually seen from the perspective of both the State and the individual citizen. The article is aimed at analyzing the existing conceptions of social security from different perspectives – political, economic efficiency, and narrative. An analysis of political theories of social security (majority rational voting; pressure groups has determined that they are based on the redistribution processes, and winning of the individual economic agents is achieved in the political struggle for various «social prizes». An analysis of theories of efficiency (optimal redistribution; optimal retirement insurance; prodigal father; misguided Keynesian; longevity insurance; government economizes on administration costs; return on human capital investment has determined that they rely on market «fiasco» and can help in understanding which from the social protection programs minimize market failures. An analysis of the descriptive (narrative theories (chain letters; lump of labor; monopoly capitalism; nearly rational policy has determined that they are difficult subject to the mathematical interpretation and partially repeat ideas of the previous concepts.

  8. Actuator disc edge singularity. The key to a revised actuator disc concept and momentum theory

    Energy Technology Data Exchange (ETDEWEB)

    Kuik, G.A.M. van (The Wind Energy Group of the Technical University Eindhoven (NL))

    1989-01-01

    Since the beginning of rotor aerodynamics the actuator disc momentum theory occupies a prominant place in almost any textbook on this subject. Specially in axial flow the theory provides an easy and rather accurate performance prediction. The results first obtained by Lanchester for the induced power of a hovering rotor and the maximum power of a wind turbine are still used as guidelines for complicated calculations. On the other hand, experimental results for propellers are known to deviate systematically (some 10%) from the momentum theory results. This is commonly attributed to the differences between a real rotor and an actuator disc. However, some actuator disc- and actuator strip (the 2-dimensional version) experiments are described in literature, showing the same deviations from momentum theory results. Therefore, apart from the question how representative an actuator disc is for a real rotor, the actuator disc concept itself may be inadequate. This problem is the subject of the work describe here. It will be shown that the classical actuator disc concept ignores discrete forces resulting from a flow singularity at the edge of the disc. The (extended) momentum theory, applied to this actuator strip model, shows a shift of the results towards the experimental data, and for the static case (hover) even a quantitative agreement is obtained. (author) 12 refs.

  9. The extended object-grasping network.

    Science.gov (United States)

    Gerbella, Marzio; Rozzi, Stefano; Rizzolatti, Giacomo

    2017-10-01

    Grasping is the most important skilled motor act of primates. It is based on a series of sensorimotor transformations through which the affordances of the objects to be grasped are transformed into appropriate hand movements. It is generally accepted that a circuit formed by inferior parietal areas AIP and PFG and ventral premotor area F5 represents the core circuit for sensorimotor transformations for grasping. However, selection and control of appropriate grip should also depend on higher-order information, such as the meaning of the object to be grasped, and the overarching goal of the action in which grasping is embedded. In this review, we describe recent findings showing that specific sectors of the ventrolateral prefrontal cortex are instrumental in controlling higher-order aspects of grasping. We show that these prefrontal sectors control the premotor cortex through two main gateways: the anterior subdivision of ventral area F5-sub-area F5a-, and the pre-supplementary area (area F6). We then review functional studies showing that both F5a and F6, besides being relay stations of prefrontal information, also play specific roles in grasping. Namely, sub-area F5a is involved in stereoscopic analysis of 3D objects, and in planning cue-dependent grasping activity. As for area F6, this area appears to play a crucial role in determining when to execute the motor program encoded in the parieto-premotor circuit. The recent discovery that area F6 contains a set of neurons encoding specific grip types suggests that this area, besides controlling "when to go", also may control the grip type, i.e., "how to go". We conclude by discussing clinical syndromes affecting grasping actions and their possible mechanisms.

  10. “AGREEMENTS”, “DECISIONS” AND “CONCERTED PRACTICES”: KEY CONCEPTS IN THE ANALYSIS OF ANTICOMPETITIVE AGREEMENTS

    Directory of Open Access Journals (Sweden)

    CRISTINA CUCU

    2013-05-01

    Full Text Available In their economic activity, undertakings conclude many agreements between them. But agreements between undertakings which can distort the competition -anticompetitive agreements- are prohibited. The Romanian and EU law prohibit “all agreements between undertakings, decisions by associations of undertakings and concerted practices which have as their object or effect the prevention, restriction or distortion of competition”. However, the terms ”agreements”, ”decisions” or ”concerted practices” are nowhere defined in the EU Treaties or in the Romanian law. These terms are key concepts in the analysis of anticompetitive agreements which can distort the competition. In the lack of a legal definition, these concepts have generated a complex body of jurisprudence, which has to be identified. The analysis of these key concepts necessarily entails the conceptual delimitation of the notions. On this purpose, the relevant legal provisions will be identified in the Romanian and EU law, as well as the decisions of the European Court of Justice in this matter. The present paper intends to present the conceptual evolution of the analysed notions, paying special attention to concerted practices and to parallel behaviour in price fixing on the market.

  11. Proof-of-concept of real-world quantum key distribution with quantum frames

    International Nuclear Information System (INIS)

    Lucio-Martinez, I; Mo, X; Tittel, W; Chan, P; Hosier, S

    2009-01-01

    We propose a fibre-based quantum key distribution system, which employs polarization qubits encoded into faint laser pulses. As a novel feature, it allows sending of classical framing information via sequences of strong laser pulses that precede the quantum data. This allows synchronization, sender and receiver identification and compensation of time-varying birefringence in the communication channel. In addition, this method also provides a platform to communicate implementation specific information such as encoding and protocol in view of future optical quantum networks. We demonstrate in a long-term (37 h) proof-of-principle study that polarization information encoded in the classical control frames can indeed be used to stabilize unwanted qubit transformation in the quantum channel. All optical elements in our setup can be operated at Gbps rates, which is a first requirement for a future system delivering secret keys at Mbps. In order to remove another bottleneck towards a high rate system, we investigate forward error correction based on low-density parity-check codes.

  12. Honour and shame as key concepts in Chrysostom’s exegesis of the Gospel of John

    Directory of Open Access Journals (Sweden)

    H.F. Stander

    2003-10-01

    Full Text Available Recently, studies have illustrated that honour and shame were core values in the Mediterranean world in general and in the Bible too. These studies usually resort to classical sources to support the claims being made. Modern scholars, who take the historical-critical approach seriously, have come to realize the importance of reading the Bible according to its appropriate cultural context, which of necessity includes an appreciation of honour and shame as social core values. However, the article shows that patristic sources have been neglected by many scholars who study the social values of the ancient world. This article illustrates the importance of these values for patristic authors. John Chrysostom’s homilies on the Gospel of John are used as an example to prove how he employed values such as honour and shame as exegetical keys to unlock the meaning of John’s gospel.

  13. Safety analysis for key design features of KALIMER-600 design concept

    International Nuclear Information System (INIS)

    Lee, Yong-Bum; Kwon, Y. M.; Kim, E. K.; Suk, S. D.; Chang, W. P.; Joeng, H. Y.; Ha, K. S.; Heo, S.

    2005-03-01

    KAERI is developing the conceptual design of a Liquid Metal Reactor, KALIMER-600 (Korea Advanced LIquid MEtal Reactor) under the Long-term Nuclear R and D Program. KALIMER-600 addresses key issues regarding future nuclear power plants such as plant safety, economics, proliferation, and waste. In this report, key safety design features are described and safety analyses results for typical ATWS accidents, containment design basis accidents, and flow blockages in the KALIMER design are presented. First, the basic approach to achieve the safety goal and main design features of KALIMER-600 are introduced in Chapter 1, and the event categorization and acceptance criteria for the KALIMER-600 safety analysis are described in Chapter 2, In Chapter 3, results of inherent safety evaluations for the KALIMER-600 conceptual design are presented. The KALIMER-600 core and plant system are designed to assure benign performance during a selected set of events without either reactor control or protection system intervention. Safety analyses for the postulated anticipated transient without scram (ATWS) have been performed using the SSC-K code to investigate the KALIMER-600 system response to the events. The objectives of Chapter 4, are to assess the response of KALIMER-600 containment to the design basis accidents and to evaluate whether the consequences are acceptable or not in the aspect of structural integrity and the exposure dose rate. In Chapter 5, the analysis of flow blockage for KALIMER-600 with the MATRA-LMR-FB code, which has been developed for the internal flow blockage in a LMR subassembly, are described. The cases with a blockage of 6-subchannel, 24-subchannel, and 54-subchannel are analyzed

  14. The Need to Disentangle Key Concepts from Ecosystem-Approach Jargon

    Science.gov (United States)

    WAYLEN, K A; HASTINGS, E J; BANKS, E A; HOLSTEAD, K L; IRVINE, R J; BLACKSTOCK, K L

    2014-01-01

    The ecosystem approach—as endorsed by the Convention on Biological Diversity (CDB) in 2000—is a strategy for holistic, sustainable, and equitable natural resource management, to be implemented via the 12 Malawi Principles. These principles describe the need to manage nature in terms of dynamic ecosystems, while fully engaging with local peoples. It is an ambitious concept. Today, the term is common throughout the research and policy literature on environmental management. However, multiple meanings have been attached to the term, resulting in confusion. We reviewed references to the ecosystem approach from 1957 to 2012 and identified 3 primary uses: as an alternative to ecosystem management or ecosystem-based management; in reference to an integrated and equitable approach to resource management as per the CBD; and as a term signifying a focus on understanding and valuing ecosystem services. Although uses of this term and its variants may overlap in meaning, typically, they do not entirely reflect the ethos of the ecosystem approach as defined by the CBD. For example, there is presently an increasing emphasis on ecosystem services, but focusing on these alone does not promote decentralization of management or use of all forms of knowledge, both of which are integral to the CBD’s concept. We highlight that the Malawi Principles are at risk of being forgotten. To better understand these principles, more effort to implement them is required. Such efforts should be evaluated, ideally with comparative approaches, before allowing the CBD’s concept of holistic and socially engaged management to be abandoned or superseded. It is possible that attempts to implement all 12 principles together will face many challenges, but they may also offer a unique way to promote holistic and equitable governance of natural resources. Therefore, we believe that the CBD’s concept of the ecosystem approach demands more attention. La Necesidad de Desenredar Conceptos Clave del

  15. Sensitization and interoception as key neurological concepts in osteopathy and other manual medicines

    Directory of Open Access Journals (Sweden)

    Giandomenico eD'alessandro

    2016-03-01

    Full Text Available AbstractHistorically, approaches used in manual medicine to explain patient reported symptoms have been focused on the so-called exteroceptive paradigm. Arguably, this mindset lacks an appropriate reading system able to interpret musculoskeletal disorders from a different perspective, where the properties of the nervous system are embraced into a more holistic and functional-related context. Interestingly, if the underpinning mechanisms of a given treatment scenario/effect are taking into account, the majority of research outcomes focuses on a proprioceptive/exteroceptive explanation, leaving ting aside the additional or even central role of interoception. Currently, to date, the application of theoretical knowledge acquired on the relatively recent neuroscientific concepts and evidence concerning of interoception, sensitization, touch, autonomic functions, inflammation, and pain into a clinical/research manual medicine scenario is lacking, even if theoretically, the impact on the possible etiological mechanisms and treatment effects seems to be important. Here, we propose the conceptual foundations for a new way of interpreting and reading patients’ clinical reported outcomes scenario based on interoception and sensitization. We argue that this will provide a foundation to create the ground for future research focusing on the hypotheses that manual therapies, specifically osteopathy, can intercede with sensitization states, at all levels, using interoceptive pathways.

  16. The quataron concept: a key to solve the problem of the nanostate

    Science.gov (United States)

    Askhabov, A. M.

    2003-04-01

    In a number of our works (Askhabov, 1998-2002) we have described a set of ideas and principles dealing with structural organization of substance in the nanorange and its role for formation of crystalline and noncrystalline materials. These ideas have been collectively referred to as the “quataron concept”. Central in this new concept is the idea that there are specific nanosize clusters arising under non-equilibrium conditions. These clusters are understood as a peculiar form of structural organization of substance at the nanolevel and referred to as "hidden" phase clusters or quatarons. As inequilibrium objects, quatarons are capable of self-organization and self-development. With their valencies fully realized (in covalent interactions), they can become large molecules; with a three-dimensional ordering (atom arrangement in a crystal lattice) they will produce crystalline particles. Quatarons are the basis for all kinds of equilibrium nanostructures from ordinary tetra- and octahedral groupings to the widely known fullerenes or dense dodecahedral and icosahedral clusters, colloidal, fractal particles. In particular, the quataron theory offers a very simple solution to the fullerene problem. Quatarons are fullerene predecessors. The fullerene architecture is dictated by hollow quatarons. Besides, it has been found that only clusters more than ~1.2 nm in size can become potenial centers of crystallization. Thus, quatarons seem to be behind all the rest of nanoparticles, including nanocrystals. This theory also broadens our understanding of the amorphous state. If for some reason quatarons or their aggregates fail to crystallize, for example, as a result of the fractal structure of the cluster surface or owing to their non-crystallographic (icosahedral) shape, then in the condensed state they give rise to a special class of solid ultradisperse materials (quatarites) of various degrees of ordering. The closest analogue of such materials is opal, a material made

  17. Updating the mitochondrial free radical theory of aging: an integrated view, key aspects, and confounding concepts.

    Science.gov (United States)

    Barja, Gustavo

    2013-10-20

    An updated version of the mitochondrial free radical theory of aging (MFRTA) and longevity is reviewed. Key aspects of the theory are emphasized. Another main focus concerns common misconceptions that can mislead investigators from other specialties, even to wrongly discard the theory. Those different issues include (i) the main reactive oxygen species (ROS)-generating site in the respiratory chain in relation to aging and longevity: complex I; (ii) the close vicinity or even contact between that site and the mitochondrial DNA, in relation to the lack of local efficacy of antioxidants and to sub-cellular compartmentation; (iii) the relationship between mitochondrial ROS production and oxygen consumption; (iv) recent criticisms on the MFRTA; (v) the widespread assumption that ROS are simple "by-products" of the mitochondrial respiratory chain; (vi) the unnecessary postulation of "vicious cycle" hypotheses of mitochondrial ROS generation which are not central to the free radical theory of aging; and (vii) the role of DNA repair concerning endogenous versus exogenous damage. After considering the large body of data already available, two general characteristics responsible for the high maintenance degree of long-lived animals emerge: (i) a low generation rate of endogenous damage: and (ii) the possession of tissue macromolecules that are highly resistant to oxidative modification.

  18. Safety Analysis for Key Design Features of KALIMER-600 Design Concept

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yong Bum; Kwon, Y. M.; Kim, E. K.; Suk, S. D.; Chang, W. P.; Jeong, H. Y.; Ha, K. S

    2007-02-15

    This report contains the safety analyses of the KALIMER-600 conceptual design which KAERI has been developing under the Long-term Nuclear R and D Program. The analyses have been performed reflecting the design developments during the second year of the 4th design phase in the program. The specific presentations are the key design features with the safety principles for achieving the safety objectives, the event categorization and safety criteria, and results on the safety analyses for the DBAs and ATWS events, the containment performance, and the channel blockages. The safety analyses for both the DBAs and ATWS events have been performed using SSC-K version 1.3., and the results have shown the fulfillment of the safety criteria for DBAs with conservative assumptions. The safety margins as well as the inherent safety also have been confirmed for the ATWS events. For the containment performance analysis, ORIGEN-2.1 and CONTAIN-LMR have been used. In results, the structural integrity has been acceptable and the evaluated exposure dose rate has been complied with 10 CFR 100 and PAG limits. The analysis results for flow blockages of 6-subchannels, 24-subchannels, and 54- subchannels with the MATRA-LMR-FB code, have assured the integrity of subassemblies.

  19. Developmental programming: the concept, large animal models, and the key role of uteroplacental vascular development.

    Science.gov (United States)

    Reynolds, L P; Borowicz, P P; Caton, J S; Vonnahme, K A; Luther, J S; Hammer, C J; Maddock Carlin, K R; Grazul-Bilska, A T; Redmer, D A

    2010-04-01

    Developmental programming refers to the programming of various bodily systems and processes by a stressor of the maternal system during pregnancy or during the neonatal period. Such stressors include nutritional stress, multiple pregnancy (i.e., increased numbers of fetuses in the gravid uterus), environmental stress (e.g., high environmental temperature, high altitude, prenatal steroid exposure), gynecological immaturity, and maternal or fetal genotype. Programming refers to impaired function of numerous bodily systems or processes, leading to poor growth, altered body composition, metabolic dysfunction, and poor productivity (e.g., poor growth, reproductive dysfunction) of the offspring throughout their lifespan and even across generations. A key component of developmental programming seems to be placental dysfunction, leading to altered fetal growth and development. We discuss various large animal models of developmental programming and how they have and will continue to contribute to our understanding of the mechanisms underlying altered placental function and developmental programming, and, further, how large animal models also will be critical to the identification and application of therapeutic strategies that will alleviate the negative consequences of developmental programming to improve offspring performance in livestock production and human medicine.

  20. Bone indicators of grasping hands in lizards

    Directory of Open Access Journals (Sweden)

    Gabriela Fontanarrosa

    2016-05-01

    Full Text Available Grasping is one of a few adaptive mechanisms that, in conjunction with clinging, hooking, arm swinging, adhering, and flying, allowed for incursion into the arboreal eco-space. Little research has been done that addresses grasping as an enhanced manual ability in non-mammalian tetrapods, with the exception of studies comparing the anatomy of muscle and tendon structure. Previous studies showed that grasping abilities allow exploitation for narrow branch habitats and that this adaptation has clear osteological consequences. The objective of this work is to ascertain the existence of morphometric descriptors in the hand skeleton of lizards related to grasping functionality. A morphological matrix was constructed using 51 morphometric variables in 278 specimens, from 24 genera and 13 families of Squamata. To reduce the dimensions of the dataset and to organize the original variables into a simpler system, three PCAs (Principal Component Analyses were performed using the subsets of (1 carpal variables, (2 metacarpal variables, and (3 phalanges variables. The variables that demonstrated the most significant contributions to the construction of the PCA synthetic variables were then used in subsequent analyses. To explore which morphological variables better explain the variations in the functional setting, we ran Generalized Linear Models for the three different sets. This method allows us to model the morphology that enables a particular functional trait. Grasping was considered the only response variable, taking the value of 0 or 1, while the original variables retained by the PCAs were considered predictor variables. Our analyses yielded six variables associated with grasping abilities: two belong to the carpal bones, two belong to the metacarpals and two belong to the phalanges. Grasping in lizards can be performed with hands exhibiting at least two different independently originated combinations of bones. The first is a combination of a highly

  1. Grasping the Formless in Stones

    DEFF Research Database (Denmark)

    Aktor, Mikael

    2017-01-01

    and the repertoire of used forms. The chapter demonstrates that neither anthropomorphic perceptions nor the agency of the stone material alone make up the ritual aesthetics in which the stones are involved. Rather, applying concepts from landscape phenomenology and cognitive theories including the role of material...

  2. A perspective of some key issues related to the evolution of safeguards, the state level and regional concepts

    International Nuclear Information System (INIS)

    Fernandez Moreno, S.

    2013-01-01

    This presentation is focused on the implementation of safeguards at present and the directions that they could be taken in the future. There are some key questions to be answered in the implementation of international safeguards that are aimed at helping to determine more clearly what safeguards will be more effective and efficient under the so called 'state-level concept' (SLC). A first and important step is to agree on a definition and scope of the SLC and to determine how the IAEA and relevant States could achieve a smooth transition from the historic criteria based safeguards systems to a new one based on the SLC that would be more flexible, but yet technically oriented and non-discriminatory. A second issue is to fully reflect on the factors that are influencing safeguards developments and that impact on their future shape. Some suggestions about enhancing safeguard implementation at present and in the future include first: a fresh look to the approach to safeguards cooperation: the IAEA has to revisit its activities to assist states in establishing good SSAC (State Systems of Accounting and Control), and secondly: investigating and promoting the development of concepts and technologies to share its verification capabilities with states and regional organizations. Another key consideration to the future of safeguards is the people. Adequate staff and the existence of appropriate training and education in safeguards are very important considerations to ensure effective and professional safeguards. Highly technically qualified staff in nuclear sciences is vital to build competence in safeguards in states, the IAEA, and regional organizations. The paper is followed by the slides of the presentation. (authors)

  3. An expert system for automated robotic grasping

    International Nuclear Information System (INIS)

    Stansfield, S.A.

    1990-01-01

    Many US Department of Energy sites and facilities will be environmentally remediated during the next several decades. A number of the restoration activities (e.g., decontamination and decommissioning of inactive nuclear facilities) can only be carried out by remote means and will be manipulation-intensive tasks. Experience has shown that manipulation tasks are especially slow and fatiguing for the human operator of a remote manipulator. In this paper, the authors present a rule-based expert system for automated, dextrous robotic grasping. This system interprets the features of an object to generate hand shaping and wrist orientation for a robot hand and arm. The system can be used in several different ways to lessen the demands on the human operator of a remote manipulation system - either as a fully autonomous grasping system or one that generates grasping options for a human operator and then automatically carries out the selected option

  4. Human Grasp Assist Device With Exoskeleton

    Science.gov (United States)

    Bergelin, Bryan J (Inventor); Ihrke, Chris A. (Inventor); Davis, Donald R. (Inventor); Linn, Douglas Martin (Inventor); Bridgwater, Lyndon B. J. (Inventor)

    2014-01-01

    A grasp assist system includes a glove, actuator assembly, and controller. The glove includes a digit, i.e., a finger or thumb, and a force sensor. The sensor measures a grasping force applied to an object by an operator wearing the glove. Phalange rings are positioned with respect to the digit. A flexible tendon is connected at one end to one of the rings and is routed through the remaining rings. An exoskeleton positioned with respect to the digit includes hinged interconnecting members each connected to a corresponding ring, and/or a single piece of slotted material. The actuator assembly is connected to another end of the tendon. The controller calculates a tensile force in response to the measured grasping force, and commands the tensile force from the actuator assembly to thereby pull on the tendon. The exoskeleton offloads some of the tensile force from the operator's finger to the glove.

  5. Getting the right grasp on executive function

    Directory of Open Access Journals (Sweden)

    Claudia L R Gonzalez

    2014-04-01

    Full Text Available Executive Function (EF refers to important socio-emotional and cognitive skills that are known to be highly correlated with both academic and life success. EF is a blanket term that is considered to include self-regulation, working memory, and planning. Recent studies have shown a relationship between EF and motor control. The emergence of motor control coincides with that of EF, hence understanding the relationship between these two domains could have significant implications for early detection and remediation of later EF deficits. The purpose of the current study was to investigate this relationship in young children. This study incorporated the Behavioural Rating Inventory of Executive Function (BRIEF and two motor assessments with a focus on precision grasping to test this hypothesis. The BRIEF is comprised of two indices of EF: 1 the Behavioral Regulation Index (BRI containing three subscales: Inhibit, Shift, and Emotional Control; 2 the Metacognition Index (MI containing five subscales: Initiate, Working Memory, Plan/Organize, Organization of Materials, and Monitor. A global executive composite (GEC is derived from the two indices. In this study, right-handed children aged 5-6 and 9-10 were asked to: grasp-to-construct (Lego® models; and grasp-to-place (wooden blocks, while their parents completed the BRIEF questionnaire. Analysis of results indicated significant correlations between the strength of right hand preference for grasping and numerous elements of the BRIEF including the BRI, MI, and GEC. Specifically, the more the right hand was used for grasping the better the EF ratings. In addition, patterns of space-use correlated with the GEC in several subscales of the BRIEF. Finally and remarkably, the results also showed a reciprocal relationship between hand and space use for grasping and EF. These findings are discussed with respect to: 1 the developmental overlap of motor and executive functions; 2 detection of EF deficits through

  6. From robot to human grasping simulation

    CERN Document Server

    León, Beatriz; Sancho-Bru, Joaquin

    2013-01-01

    The human hand and its dexterity in grasping and manipulating objects are some of the hallmarks of the human species. For years, anatomic and biomechanical studies have deepened the understanding of the human hand’s functioning and, in parallel, the robotics community has been working on the design of robotic hands capable of manipulating objects with a performance similar to that of the human hand. However, although many researchers have partially studied various aspects, to date there has been no comprehensive characterization of the human hand’s function for grasping and manipulation of

  7. SEOM's Sentinel-3/OLCI' project CAWA: advanced GRASP aerosol retrieval

    Science.gov (United States)

    Dubovik, Oleg; litvinov, Pavel; Huang, Xin; Aspetsberger, Michael; Fuertes, David; Brockmann, Carsten; Fischer, Jürgen; Bojkov, Bojan

    2016-04-01

    The CAWA "Advanced Clouds, Aerosols and WAter vapour products for Sentinel-3/OLCI" ESA-SEOM project aims on the development of advanced atmospheric retrieval algorithms for the Sentinel-3/OLCI mission, and is prepared using Envisat/MERIS and Aqua/MODIS datasets. This presentation discusses mainly CAWA aerosol product developments and results. CAWA aerosol retrieval uses recently developed GRASP algorithm (Generalized Retrieval of Aerosol and Surface Properties) algorithm described by Dubovik et al. (2014). GRASP derives extended set of atmospheric parameters using multi-pixel concept - a simultaneous fitting of a large group of pixels under additional a priori constraints limiting the time variability of surface properties and spatial variability of aerosol properties. Over land GRASP simultaneously retrieves properties of both aerosol and underlying surface even over bright surfaces. GRAPS doesn't use traditional look-up-tables and performs retrieval as search in continuous space of solution. All radiative transfer calculations are performed as part of the retrieval. The results of comprehensive sensitivity tests, as well as results obtained from real Envisat/MERIS data will be presented. The tests analyze various aspects of aerosol and surface reflectance retrieval accuracy. In addition, the possibilities of retrieval improvement by means of implementing synergetic inversion of a combination of OLCI data with observations by SLSTR are explored. Both the results of numerical tests, as well as the results of processing several years of Envisat/MERIS data illustrate demonstrate reliable retrieval of AOD (Aerosol Optical Depth) and surface BRDF. Observed retrieval issues and advancements will be discussed. For example, for some situations we illustrate possibilities of retrieving aerosol absorption - property that hardly accessible from satellite observations with no multi-angular and polarimetric capabilities.

  8. Grasp Representations Depend on Knowledge and Attention

    Science.gov (United States)

    Chua, Kao-Wei; Bub, Daniel N.; Masson, Michael E. J.; Gauthier, Isabel

    2018-01-01

    Seeing pictures of objects activates the motor cortex and can have an influence on subsequent grasping actions. However, the exact nature of the motor representations evoked by these pictures is unclear. For example, action plans engaged by pictures could be most affected by direct visual input and computed online based on object shape.…

  9. Passive Aerial Grasping of Ferrous Objects

    KAUST Repository

    Fiaz, Usman Amin

    2017-10-19

    Aerial transportation is probably the most efficient way to supply quick and effective aid especially in cases of emergency like search and rescue operations. Thus the ability to grasp and deliver objects is of vital importance in all sorts of unmanned and autonomous aerial operations. We detail a simple yet novel approach for aerial grasping of ferrous objects using a passive magnetic pickup and an impulse based drop mechanism. The design enables our gripper to grasp ferrous objects using single as well as multiple gripping pads, with visual as well as pickup and drop feedback. We describe the various components of the gripper with emphasis on its low mass and high lift capability since weight is a matter of high consideration in all aerial applications. In addition, we investigate and address the issues that may cause our design to fail. We demonstrate by experiments that the proposed design is robust and effective, based on its high payload capability, its sturdiness against possible slide during aggressive aerial maneuvers, and optimum performance of the drop mechanism for the designed range of payloads. We also show that the gripper is able to pick up and drop a single as well as multiple ferrous objects of different shapes, curvature, and inclination, which also involves picking up an object and then grasping the next, while keeping hold of the previous one.

  10. How to grasp a ripe tomato

    NARCIS (Netherlands)

    Verhagen, L.

    2012-01-01

    Fortunately, we don’t have to think about this when we are standing in the supermarket after a busy day. We adjust our grip without effort, making sure we don’t squish an overripe tomato, while we firmly grasp a hard green one. This is actually a complex task in which humans are surprisingly

  11. Grasping completions: Towards a new paradigm

    NARCIS (Netherlands)

    Lommertzen, J.; Meulenbroek, R.G.J.; Lier, R.J. van

    2006-01-01

    We studied contextual effects of amodal completion in both a primed-matching task, and a grasping task in a within-subjects design with twenty-nine participants. Stimuli were partly occluded cylindrical objects that could have indentations (or protrusions) at regular intervals along the contour. The

  12. Passive Aerial Grasping of Ferrous Objects

    KAUST Repository

    Fiaz, Usman; Toumi, Noureddine; Shamma, Jeff S.

    2017-01-01

    Aerial transportation is probably the most efficient way to supply quick and effective aid especially in cases of emergency like search and rescue operations. Thus the ability to grasp and deliver objects is of vital importance in all sorts of unmanned and autonomous aerial operations. We detail a simple yet novel approach for aerial grasping of ferrous objects using a passive magnetic pickup and an impulse based drop mechanism. The design enables our gripper to grasp ferrous objects using single as well as multiple gripping pads, with visual as well as pickup and drop feedback. We describe the various components of the gripper with emphasis on its low mass and high lift capability since weight is a matter of high consideration in all aerial applications. In addition, we investigate and address the issues that may cause our design to fail. We demonstrate by experiments that the proposed design is robust and effective, based on its high payload capability, its sturdiness against possible slide during aggressive aerial maneuvers, and optimum performance of the drop mechanism for the designed range of payloads. We also show that the gripper is able to pick up and drop a single as well as multiple ferrous objects of different shapes, curvature, and inclination, which also involves picking up an object and then grasping the next, while keeping hold of the previous one.

  13. Grasping Unknown Objects in an Early Cognitive Vision System

    DEFF Research Database (Denmark)

    Popovic, Mila

    2011-01-01

    Grasping of unknown objects presents an important and challenging part of robot manipulation. The growing area of service robotics depends upon the ability of robots to autonomously grasp and manipulate a wide range of objects in everyday environments. Simple, non task-specific grasps of unknown ...... and comparing vision-based grasping methods, and the creation of algorithms for bootstrapping a process of acquiring world understanding for artificial cognitive agents....... presents a system for robotic grasping of unknown objects us- ing stereo vision. Grasps are defined based on contour and surface information provided by the Early Cognitive Vision System, that organizes visual informa- tion into a biologically motivated hierarchical representation. The contributions...... of the thesis are: the extension of the Early Cognitive Vision representation with a new type of feature hierarchy in the texture domain, the definition and evaluation of contour based grasping methods, the definition and evaluation of surface based grasping methods, the definition of a benchmark for testing...

  14. A General Contact Force Analysis of an Under-Actuated Finger in Robot Hand Grasping

    Directory of Open Access Journals (Sweden)

    Xuan Vinh Ha

    2016-02-01

    Full Text Available This paper develops a mathematical analysis of contact forces for the under-actuated finger in a general under-actuated robotic hand during grasping. The concept of under-actuation in robotic grasping with fewer actuators than degrees of freedom (DOF, through the use of springs and mechanical limits, allows the hand to adjust itself to an irregularly shaped object without complex control strategies and sensors. Here the main concern is the contact forces, which are important elements in grasping tasks, based on the proposed mathematical analysis of their distributions of the n-DOF under-actuated finger. The simulation results, along with the 3-DOF finger from the ADAMS model, show the effectiveness of the mathematical analysis method, while comparing them with the measured results. The system can find magnitudes of the contact forces at the contact positions between the phalanges and the object.

  15. Functional classification of grasp strategies used by hemiplegic patients.

    Directory of Open Access Journals (Sweden)

    Alicia García Álvarez

    Full Text Available This study aimed to identify and qualify grasp-types used by patients with stroke and determine the clinical parameters that could explain the use of each grasp. Thirty-eight patients with chronic stroke-related hemiparesis and a range of motor and functional capacities (17 females and 21 males, aged 25-78, and 10 healthy subjects were included. Four objects were used (tissue packet, teaspoon, bottle and tennis ball. Participants were instructed to "grasp the object as if you are going to use it". Three trials were video-recorded for each object. A total of 456 grasps were analysed and rated using a custom-designed Functional Grasp Scale. Eight grasp-types were identified from the analysis: healthy subjects used Multi-pulpar, Pluri-digital, Lateral-pinch and Palmar grasps (Standard Grasps. Patients used the same grasps with in addition Digito-palmar, Raking, Ulnar and Interdigital grasps (Alternative Grasps. Only patients with a moderate or relatively good functional ability used Standard grasps. The correlation and regression analyses showed this was conditioned by sufficient finger and elbow extensor strength (Pluri-digital grasp; thumb extensor and wrist flexor strength (Lateral pinch or in forearm supinator strength (Palmar grasp. By contrast, the patients who had severe impairment used Alternative grasps that did not involve the thumb. These strategies likely compensate specific impairments. Regression and correlation analyses suggested that weakness had a greater influence over grasp strategy than spasticity. This would imply that treatment should focus on improving hand strength and control although reducing spasticity may be useful in some cases.

  16. On transferability and contexts when using simulated grasp databases

    DEFF Research Database (Denmark)

    Jørgensen, Jimmy Alison; Ellekilde, Lars-Peter; Kraft, Dirk

    2015-01-01

    It has become a common practice to use simulation to generate large databases of good grasps for grasp planning in robotics research. However, the existence of a generic simulation context that enables the generation of high quality grasps that can be used in several different contexts such as bi...

  17. Locomotion and Grasping impairment in preschoolers with autism spectrum disorder

    Directory of Open Access Journals (Sweden)

    Francesca Fulceri

    2015-08-01

    Full Text Available Objective: To investigate expressiveness of motor impairment in autism spectrum disorder (ASD and its correlation with developmental and clinical features of ASD. Method: Thirty-five male preschoolers with ASD completed the Peabody Developmental Motor Scales-2 (PDMS-2; Folio and Fewell, 2000 and underwent a multidisciplinary assessment including medical examination, standardized assessment of cognitive abilities, administration of Autism_Diagnostic_Observation_Schedule (ADOS and a parent interview about adaptive skills. Results: Results revealed a substantial impairment in locomotion and grasping skills. Both fine and gross motor skills were significantly correlated with non verbal IQ and adaptive behaviours (p<0.01 but not with chronological age or ADOS scores. Children with weaker motor skills have greater cognitive and adaptive behaviours deficits. Conclusions: Motor development in ASD can be detected at preschool age and locomotion and grasping skills are substantially the most impaired area. These findings support the need to assess motor skills in preschoolers with ASD in addition to other developmental skill areas. Along with the increasingly acknowledged importance of motor skills for subsequent social, cognitive, and communicative development our findings support the need to consider motor intervention as a key area in therapeutic program to improve outcome in preschoolers with ASD.

  18. A study of how precursor key concepts for organic chemistry success are understood by general chemistry students

    Science.gov (United States)

    Meyer, Patrick Gerard

    This study examines college student understanding of key concepts that will support future organic chemistry success as determined by university instructors. During four one-hour individual interviews the sixteen subjects attempted to solve general chemistry problems. A think-aloud protocol was used along with a whiteboard where the students could draw and illustrate their ideas. The protocols for the interviews were adapted from the Covalent Structure and Bonding two-tiered multiple choice diagnostic instrument (Peterson, Treagust, & Garnett, 1989) and augmented by the Geometry and Polarity of Molecules single-tiered multiple choice instrument (Furio & Calatayud, 1996). The interviews were videotaped, transcribed, and coded for analysis to determine the subjects' understanding of the key ideas. The subjects displayed many misconceptions that were summarized into nine assertions about student conceptualization of chemistry. (1) Many students misunderstand the location and nature of intermolecular forces. (2) Some think electronegativity differences among atoms in a molecule are sufficient to make the molecule polar, regardless of spatial arrangement. (3) Most know that higher phase change temperatures imply stronger intermolecular attractions, but many do not understand the difference between covalent molecular and covalent network substances. (4) Many have difficulty deciding whether a molecule is polar or non-polar, often confusing bilateral symmetry with spatial symmetry in all three dimensions. (5) Many cannot reliably draw correct Lewis structures due to carelessness and overuse of flawed algorithms. (6) Many are confused by how electrons can both repel one other and facilitate bonding between atoms via orbitals---this seems oxymoronic to them. (7) Many cannot explain why the atoms of certain elements do not follow the octet rule and some believe the octet rule alone can determine the shape of a molecule. (8) Most do know that electronegativity and polarity

  19. Automatic Grasp Generation and Improvement for Industrial Bin-Picking

    DEFF Research Database (Denmark)

    Kraft, Dirk; Ellekilde, Lars-Peter; Rytz, Jimmy Alison

    2014-01-01

    and achieve comparable results and that our learning approach can improve system performance significantly. Automatic bin-picking is an important industrial process that can lead to significant savings and potentially keep production in countries with high labour cost rather than outsourcing it. The presented......This paper presents work on automatic grasp generation and grasp learning for reducing the manual setup time and increase grasp success rates within bin-picking applications. We propose an approach that is able to generate good grasps automatically using a dynamic grasp simulator, a newly developed...

  20. Robust Robot Grasp Detection in Multimodal Fusion

    Directory of Open Access Journals (Sweden)

    Zhang Qiang

    2017-01-01

    Full Text Available Accurate robot grasp detection for model free objects plays an important role in robotics. With the development of RGB-D sensors, object perception technology has made great progress. Reach feature expression by the colour and the depth data is a critical problem that needs to be addressed in order to accomplish the grasping task. To solve the problem of data fusion, this paper proposes a convolutional neural networks (CNN based approach combined with regression and classification. In the CNN model, the colour and the depth modal data are deeply fused together to achieve accurate feature expression. Additionally, Welsch function is introduced into the approach to enhance robustness of the training process. Experiment results demonstrates the superiority of the proposed method.

  1. Stereo vision based automated grasp planning

    International Nuclear Information System (INIS)

    Wilhelmsen, K.; Huber, L.; Silva, D.; Grasz, E.; Cadapan, L.

    1995-02-01

    The Department of Energy has a need for treating existing nuclear waste. Hazardous waste stored in old warehouses needs to be sorted and treated to meet environmental regulations. Lawrence Livermore National Laboratory is currently experimenting with automated manipulations of unknown objects for sorting, treating, and detailed inspection. To accomplish these tasks, three existing technologies were expanded to meet the increasing requirements. First, a binocular vision range sensor was combined with a surface modeling system to make virtual images of unknown objects. Then, using the surface model information, stable grasp of the unknown shaped objects were planned algorithmically utilizing a limited set of robotic grippers. This paper is an expansion of previous work and will discuss the grasp planning algorithm

  2. Fast grasping of unknown objects using principal component analysis

    Science.gov (United States)

    Lei, Qujiang; Chen, Guangming; Wisse, Martijn

    2017-09-01

    Fast grasping of unknown objects has crucial impact on the efficiency of robot manipulation especially subjected to unfamiliar environments. In order to accelerate grasping speed of unknown objects, principal component analysis is utilized to direct the grasping process. In particular, a single-view partial point cloud is constructed and grasp candidates are allocated along the principal axis. Force balance optimization is employed to analyze possible graspable areas. The obtained graspable area with the minimal resultant force is the best zone for the final grasping execution. It is shown that an unknown object can be more quickly grasped provided that the component analysis principle axis is determined using single-view partial point cloud. To cope with the grasp uncertainty, robot motion is assisted to obtain a new viewpoint. Virtual exploration and experimental tests are carried out to verify this fast gasping algorithm. Both simulation and experimental tests demonstrated excellent performances based on the results of grasping a series of unknown objects. To minimize the grasping uncertainty, the merits of the robot hardware with two 3D cameras can be utilized to suffice the partial point cloud. As a result of utilizing the robot hardware, the grasping reliance is highly enhanced. Therefore, this research demonstrates practical significance for increasing grasping speed and thus increasing robot efficiency under unpredictable environments.

  3. The magic grasp: motor expertise in deception.

    Directory of Open Access Journals (Sweden)

    Cristiana Cavina-Pratesi

    2011-02-01

    Full Text Available Most of us are poor at faking actions. Kinematic studies have shown that when pretending to pick up imagined objects (pantomimed actions, we move and shape our hands quite differently from when grasping real ones. These differences between real and pantomimed actions have been linked to separate brain pathways specialized for different kinds of visuomotor guidance. Yet professional magicians regularly use pantomimed actions to deceive audiences.In this study, we tested whether, despite their skill, magicians might still show kinematic differences between grasping actions made toward real versus imagined objects. We found that their pantomimed actions in fact closely resembled real grasps when the object was visible (but displaced (Experiment 1, but failed to do so when the object was absent (Experiment 2.We suggest that although the occipito-parietal visuomotor system in the dorsal stream is designed to guide goal-directed actions, prolonged practice may enable it to calibrate actions based on visual inputs displaced from the action.

  4. Evaluation of Human Prehension Using Grasp Quality Measures

    Directory of Open Access Journals (Sweden)

    Beatriz León

    2012-10-01

    Full Text Available One of the main features of the human hand is its grasping ability. Robot grasping has been studied for years and different quality measures have been proposed to evaluate the stability and manipulability of grasps. Although the human hand is obviously more complex than robot hands, the methods used in robotics might be adopted to study the human grasp. The purpose of this work is to propose a set of measures that allow the evaluation of different aspects of the human grasp. The most common robotic grasp quality measures have been adapted to the evaluation of the human hand and a new quality measure – the fatigue index – is proposed in order to incorporate the biomechanical aspect into the evaluation. The minimum set of indices that allows the evaluation of the different aspects of the grasp is obtained from the analysis of a human prehension experiment.

  5. Research and Teaching: An Investigation of the Evolution of High School and Undergraduate Student Researchers' Understanding of Key Science Ethics Concepts

    Science.gov (United States)

    Mabrouk, Patricia Ann

    2013-01-01

    High school and undergraduate research students were surveyed over the 10-week period of their summer research programs to investigate their understanding of key concepts in science ethics and whether their understanding changed over the course of their summer research experiences. Most of the students appeared to understand the issues relevant to…

  6. Addressing key concepts in physical geography through interactive learning activities in an online geo-ICT environment

    Science.gov (United States)

    Verstraeten, Gert; Steegen, An; Martens, Lotte

    2016-04-01

    The increasing number of geospatial datasets and free online geo-ICT tools offers new opportunities for education in Earth Sciences. Geospatial technology indeed provides an environment through which interactive learning can be introduced in Earth Sciences curricula. However, the effectiveness of such e-learning approaches in terms of learning outcomes has rarely been addressed. Here, we present our experience with the implementation of digital interactive learning activities within an introductory Physical Geography course attended by 90 undergraduate students in Geography, Geology, Biology and Archaeology. Two traditional lectures were replaced by interactive sessions (each 2 h) in a flexible classroom where students had to work both in team and individually in order to explore some key concepts through the integrated use of geospatial data within Google EarthTM. A first interactive lesson dealt with the classification of river systems and aimed to examine the conditions under which rivers tend to meander or to develop a braided pattern. Students were required to collect properties of rivers (river channel pattern, channel slope, climate, discharge, lithology, vegetation, etc). All these data are available on a global scale and have been added as separate map layers in Google EarthTM. Each student collected data for at least two rivers and added this information to a Google Drive Spreadsheet accessible to the entire group. This resulted in a database of more than one hundred rivers spread over various environments worldwide. In a second phase small groups of students discussed the potential relationships between river channel pattern and its controlling factors. Afterwards, the findings of each discussion group were presented to the entire audience. The same set-up was followed in a second interactive session to explore spatial variations in ecosystem properties such as net primary production and soil carbon content. The qualitative evaluation of both interactive

  7. Managing distributed dynamic systems with spatial grasp technology

    CERN Document Server

    Sapaty, Peter Simon

    2017-01-01

    The book describes a novel ideology and supporting information technology for integral management of both civil and defence-orientated large, distributed dynamic systems. The approach is based on a high-level Spatial Grasp Language, SGL, expressing solutions in physical, virtual, executive and combined environments in the form of active self-evolving and self-propagating patterns spatially matching the systems to be created, modified and controlled. The communicating interpreters of SGL can be installed in key system points, which may be in large numbers (up to millions and billions) and represent equipped humans, robots, laptops, smartphones, smart sensors, etc. Operating under gestalt-inspired scenarios in SGL initially injected from any points, these systems can be effectively converted into goal-driven spatial machines (rather than computers as dealing with physical matter too) capable of responding to numerous challenges caused by growing world dynamics in the 21st century. Including numerous practical e...

  8. Research and Teaching: Correlations between Students' Written Responses to Lecture-Tutorial Questions and Their Understandings of Key Astrophysics Concepts

    Science.gov (United States)

    Eckenrode, Jeffrey; Prather, Edward E.; Wallace, Colin S.

    2016-01-01

    This article reports on an investigation into the correlations between students' understandings of introductory astronomy concepts and the correctness and coherency of their written responses to targeted Lecture-Tutorial questions.

  9. Do already grasped objects activate motor affordances?

    Science.gov (United States)

    Iani, Cristina; Ferraro, Luca; Maiorana, Natale Vincenzo; Gallese, Vittorio; Rubichi, Sandro

    2018-04-07

    This study investigated whether in a stimulus-response compatibility (SRC) task affordance effects in response to picture of graspable objects emerge when these objects appear as already grasped. It also assessed whether the observed effects could be explained as due to spatial compatibility between the most salient part in the object/display and the hand of response rather than to action potentiation. To this aim, we conducted three behavioural experiments in which participants were required to discriminate the vertical orientation (upright vs. inverted) of an object presented in the centre of the screen, while ignoring the right-left orientation of its handle. The object could be presented alone, as already grasped, as partially masked (Experiment 1) or with a human hand close to its graspable side (Experiment 2). In addition, to assess the role of perceptual salience, the object could be presented with a human hand or a non-biological (a geometrical shape) distractor located opposite to the object's graspable side. Results showed faster responses when the object's handle was located on the same side of the responding hand with a larger effect when upright objects were shown as already grasped (Experiment 1) or when a hand was displayed close to its handle (Experiment 2), and a smaller reversed effect when the hand or the geometrical shape was located opposite to the handled side (Experiment 3). We interpreted these findings as indicating that handle orientation effects emerging in SRC tasks may result from the interplay between motor affordance and spatial compatibility mechanisms.

  10. Teaching grasping points using natural movements

    OpenAIRE

    Isleyici, Yalim

    2014-01-01

    Research about tasks that robotic maids should be able to perform is an emerging research area such as cooking and cleaning. Among them, manipulation of clothes is one of the hardest tasks due to the fact that textile is highly deformable and it is hard to model a good grasping point on them. In literature there are certain algorithms depending on 3D information of the cloth but most of them are not robust. Among them, Fast Integral Normal 3D (FINDDD) descriptors is a promising way for ...

  11. Optimization by GRASP greedy randomized adaptive search procedures

    CERN Document Server

    Resende, Mauricio G C

    2016-01-01

    This is the first book to cover GRASP (Greedy Randomized Adaptive Search Procedures), a metaheuristic that has enjoyed wide success in practice with a broad range of applications to real-world combinatorial optimization problems. The state-of-the-art coverage and carefully crafted pedagogical style lends this book highly accessible as an introductory text not only to GRASP, but also to combinatorial optimization, greedy algorithms, local search, and path-relinking, as well as to heuristics and metaheuristics, in general. The focus is on algorithmic and computational aspects of applied optimization with GRASP with emphasis given to the end-user, providing sufficient information on the broad spectrum of advances in applied optimization with GRASP. For the more advanced reader, chapters on hybridization with path-relinking and parallel and continuous GRASP present these topics in a clear and concise fashion. Additionally, the book offers a very complete annotated bibliography of GRASP and combinatorial optimizat...

  12. Conceptos claves en un programa educativo Conceitos chave em um programa educativo Key Concepts in an Educational Program

    Directory of Open Access Journals (Sweden)

    MYRIAM PATRICIA PARDO TORRES

    2010-10-01

    are hereby presented on literature regarding assertive communication concepts, feelings and visions of nursing as a reciprocal and a simultaneous support for an educational program based on intervention with adolescents to promote responsible procreation. The present literature review took Ebsco-Host and Scielo as databases. Conclusion: Assertive communication is a learned social skill, which needs to be strengthened in as much as programs of sexual and reproductive health are concerned. Affection is a motivator for transmission and acquisition of knowledge in sexual and in reproductive education matters; the vision of reciprocity allows for interaction between the adolescent and the nurse and is a necessary component for mutual construction of self - care in this area, and the vision of simultaneity integrates the context as a key element in addressing the issue within a educational program.

  13. Key Concepts in an Educational Program Conceptos claves en un programa educativo Conceitos chave em um programa educativo

    Directory of Open Access Journals (Sweden)

    ARANGO MARTÍNEZ CATHERINE

    2010-10-01

    Full Text Available

    The results of the review are hereby presented on literature regarding assertive communication concepts, feelings and visions of nursing as a reciprocal and a simultaneous support for an educational program based on intervention with adolescents to promote responsible procreation. The present literature review took Ebsco-Host and Scielo as databases.

    Conclusion: Assertive communication is a learned social skill, which needs to be strengthened in as much as programs of sexual and reproductive health are concerned. Affection is a motivator for transmission and acquisition of knowledge in sexual and in reproductive education matters; the vision of reciprocity allows for interaction between the adolescent and the nurse and is a necessary component for mutual construction of self - care in this area, and the vision of simultaneity integrates the context as a key element in addressing the issue within a educational program.

    Se presentan los resultados de la revisión de literatura sobre los conceptos comunicación asertiva, afecto y las visiones de enfermería de reciprocidad y simultaneidad como sustento base de un programa educativo de intervención con adolescentes para promover la responsabilidad procreativa. La revisión bibliográfica sistemática tomó como bases de datos Ebsco-Host y Scielo.

    Conclusiones: la comunicación asertiva es una habilidad social aprendida, que es necesario fortalecer en los programas de salud sexual y reproductiva; el afecto es un elemento motivador para la transmisión y apropiación de conocimientos en educación sexual y reproductiva; la visión de reciprocidad orienta la interacción entre el (la adolescente y la (el enfermera (o componente necesario para una construcción mutua del autocuidado en este ámbito, y la visión de simultaneidad integra el contexto como elemento

  14. Testing of Visual Field with Virtual Reality Goggles in Manual and Visual Grasp Modes

    Directory of Open Access Journals (Sweden)

    Dariusz Wroblewski

    2014-01-01

    Full Text Available Automated perimetry is used for the assessment of visual function in a variety of ophthalmic and neurologic diseases. We report development and clinical testing of a compact, head-mounted, and eye-tracking perimeter (VirtualEye that provides a more comfortable test environment than the standard instrumentation. VirtualEye performs the equivalent of a full threshold 24-2 visual field in two modes: (1 manual, with patient response registered with a mouse click, and (2 visual grasp, where the eye tracker senses change in gaze direction as evidence of target acquisition. 59 patients successfully completed the test in manual mode and 40 in visual grasp mode, with 59 undergoing the standard Humphrey field analyzer (HFA testing. Large visual field defects were reliably detected by VirtualEye. Point-by-point comparison between the results obtained with the different modalities indicates: (1 minimal systematic differences between measurements taken in visual grasp and manual modes, (2 the average standard deviation of the difference distributions of about 5 dB, and (3 a systematic shift (of 4–6 dB to lower sensitivities for VirtualEye device, observed mostly in high dB range. The usability survey suggested patients’ acceptance of the head-mounted device. The study appears to validate the concepts of a head-mounted perimeter and the visual grasp mode.

  15. Testing of visual field with virtual reality goggles in manual and visual grasp modes.

    Science.gov (United States)

    Wroblewski, Dariusz; Francis, Brian A; Sadun, Alfredo; Vakili, Ghazal; Chopra, Vikas

    2014-01-01

    Automated perimetry is used for the assessment of visual function in a variety of ophthalmic and neurologic diseases. We report development and clinical testing of a compact, head-mounted, and eye-tracking perimeter (VirtualEye) that provides a more comfortable test environment than the standard instrumentation. VirtualEye performs the equivalent of a full threshold 24-2 visual field in two modes: (1) manual, with patient response registered with a mouse click, and (2) visual grasp, where the eye tracker senses change in gaze direction as evidence of target acquisition. 59 patients successfully completed the test in manual mode and 40 in visual grasp mode, with 59 undergoing the standard Humphrey field analyzer (HFA) testing. Large visual field defects were reliably detected by VirtualEye. Point-by-point comparison between the results obtained with the different modalities indicates: (1) minimal systematic differences between measurements taken in visual grasp and manual modes, (2) the average standard deviation of the difference distributions of about 5 dB, and (3) a systematic shift (of 4-6 dB) to lower sensitivities for VirtualEye device, observed mostly in high dB range. The usability survey suggested patients' acceptance of the head-mounted device. The study appears to validate the concepts of a head-mounted perimeter and the visual grasp mode.

  16. Robotic Hand with Flexible Fingers for Grasping Cylindrical Objects

    OpenAIRE

    柴田, 瑞穂

    2015-01-01

    In this manuscript, a robotic hand for grasping a cylindrical object is proposed. This robotic hand has flexible fingers that can hold a cylindrical object during moving. We introduce a grasping strategy for a cylindrical object in terms of state transition graph. In this strategy the robotic hand picks up the cylindrical object utilizing a suction device before the hand grasp the object. We also design the flexible fingers; then, we investigate the validity of this robotic hand via several e...

  17. Electromyographic Grasp Recognition for a Five Fingered Robotic Hand

    Directory of Open Access Journals (Sweden)

    Nayan M. Kakoty

    2012-09-01

    Full Text Available This paper presents classification of grasp types based on surface electromyographic signals. Classification is through radial basis function kernel support vector machine using sum of wavelet decomposition coefficients of the EMG signals. In a study involving six subjects, we achieved an average recognition rate of 86%. The electromyographic grasp recognition together with a 8-bit microcontroller has been employed to control a fivefingered robotic hand to emulate six grasp types used during 70% daily living activities.

  18. Intrinsic Hand Muscle Activation for Grasp and Horizontal Transport

    OpenAIRE

    Winges, Sara A.; Kundu, Bornali; Soechting, John F.; Flanders, Martha

    2007-01-01

    During object manipulation, the hand and arm muscles produce internal forces on the object (grasping forces) and forces that result in external translation or rotation of the object in space (transport forces). The present study tested whether the intrinsic hand muscles are actively involved in transport as well as grasping. Intrinsic hand muscle activity increased with increasing demands for grasp stability, but also showed the timing and directional tuning patterns appropriate for actively ...

  19. Assessing Grasp Stability Based on Learning and Haptic Data

    DEFF Research Database (Denmark)

    Bekiroglu, Yasemin; Laaksonen, Janne; Jørgensen, Jimmy Alison

    2011-01-01

    a probabilistic learning framework to assess grasp stability and demonstrate that knowledge about grasp stability can be inferred using information from tactile sensors. Experiments on both simulated and real data are shown. The results indicate that the idea to exploit the learning approach is applicable...... data and machine-learning methods, including AdaBoost, support vector machines (SVMs), and hidden Markov models (HMMs). In particular, we study the effect of different sensory streams to grasp stability. This includes object information such as shape; grasp information such as approach vector; tactile...

  20. Grasping trajectories in a virtual environment adhere to Weber's law.

    Science.gov (United States)

    Ozana, Aviad; Berman, Sigal; Ganel, Tzvi

    2018-06-01

    Virtual-reality and telerobotic devices simulate local motor control of virtual objects within computerized environments. Here, we explored grasping kinematics within a virtual environment and tested whether, as in normal 3D grasping, trajectories in the virtual environment are performed analytically, violating Weber's law with respect to object's size. Participants were asked to grasp a series of 2D objects using a haptic system, which projected their movements to a virtual space presented on a computer screen. The apparatus also provided object-specific haptic information upon "touching" the edges of the virtual targets. The results showed that grasping movements performed within the virtual environment did not produce the typical analytical trajectory pattern obtained during 3D grasping. Unlike as in 3D grasping, grasping trajectories in the virtual environment adhered to Weber's law, which indicates relative resolution in size processing. In addition, the trajectory patterns differed from typical trajectories obtained during 3D grasping, with longer times to complete the movement, and with maximum grip apertures appearing relatively early in the movement. The results suggest that grasping movements within a virtual environment could differ from those performed in real space, and are subjected to irrelevant effects of perceptual information. Such atypical pattern of visuomotor control may be mediated by the lack of complete transparency between the interface and the virtual environment in terms of the provided visual and haptic feedback. Possible implications of the findings to movement control within robotic and virtual environments are further discussed.

  1. Learning Grasp Strategies Composed of Contact Relative Motions

    Science.gov (United States)

    Platt, Robert, Jr.

    2007-01-01

    Of central importance to grasp synthesis algorithms are the assumptions made about the object to be grasped and the sensory information that is available. Many approaches avoid the issue of sensing entirely by assuming that complete information is available. In contrast, this paper proposes an approach to grasp synthesis expressed in terms of units of control that simultaneously change the contact configuration and sense information about the object and the relative manipulator-object pose. These units of control, known as contact relative motions (CRMs), allow the grasp synthesis problem to be recast as an optimal control problem where the goal is to find a strategy for executing CRMs that leads to a grasp in the shortest number of steps. An experiment is described that uses Robonaut, the NASA-JSC space humanoid, to show that CRMs are a viable means of synthesizing grasps. However, because of the limited amount of information that a single CRM can sense, the optimal control problem may be partially observable. This paper proposes expressing the problem as a k-order Markov Decision Process (MDP) and solving it using Reinforcement Learning. This approach is tested in a simulation of a two-contact manipulator that learns to grasp an object. Grasp strategies learned in simulation are tested on the physical Robonaut platform and found to lead to grasp configurations consistently.

  2. Shaping of Reach-to-Grasp Kinematics by Intentions

    DEFF Research Database (Denmark)

    Egmose, Ida; Køppe, Simo

    2017-01-01

    is primarily associated with transporting the hand to the object (i.e., extrinsic object properties), the decelerating part of the reach is used as a preparation for object manipulation (i.e., prepare the grasp or the subsequent action), and the grasp is associated with manipulating the object's intrinsic...

  3. Differences in fixations between grasping and viewing objects

    NARCIS (Netherlands)

    Brouwer, A.M.; Franz, V.H.; Gegenfurtner, K.R.

    2009-01-01

    Where exactly do people look when they grasp an object? An object is usually contacted at two locations, whereas the gaze can only be at one location at the time. We investigated participants' fixation locations when they grasp objects with the contact positions of both index finger and thumb being

  4. Linguistic approach to object recognition by grasping

    Energy Technology Data Exchange (ETDEWEB)

    Marik, V

    1982-01-01

    A method for recognizing both the three-dimensional object shapes and their sizes by grasping them with an antropomorphic five-finger artificial hand is described. The hand is equipped with position sensing elements in the joints of the fingers and with a tactile transducer net on the palm surface. The linguistic method uses formal grammars and languages for the pattern description. The recognition is hierarchically arranged, every level being different from the others by a formal language which has been used. On every level the pattern description is generated and verified from the symmetrical and semantical points of view. The results of the implementation of the recognition of cones, pyramides, spheres, prisms and cylinders are presented and discussed. 8 references.

  5. Visuomotor Resolution in Telerobotic Grasping with Transmission Delays

    Directory of Open Access Journals (Sweden)

    Omri Afgin

    2017-10-01

    Full Text Available Weber’s law is among the basic psychophysical laws of human perception. It determines that human sensitivity to change along a physical dimension, the just noticeable difference (JND, is linearly related to stimulus intensity. Conversely, in direct (natural, visually guided grasping, Weber’s law is violated and the JND does not depend on stimulus intensity. The current work examines adherence to Weber’s law in telerobotic grasping. In direct grasping, perception and action are synchronized during task performance. Conversely, in telerobotic control, there is an inherent spatial and temporal separation between perception and action. The understanding of perception–action association in such conditions may facilitate development of objective measures for telerobotic systems and contribute to improved interface design. Moreover, telerobotic systems offer a unique platform for examining underlying causes for the violation of Weber’s law during direct grasping. We examined whether, like direct grasping, telerobotic grasping with transmission delays violates Weber’s law. To this end, we examined perceptual assessment, grasp control, and grasp demonstration, using a telerobotic system with time delays in two spatial orientations: alongside and facing the robot. The examination framework was adapted to telerobotics from the framework used for examining Weber’s law in direct grasping. The variability of final grip apertures (FGAs in perceptual assessment increased with object size in adherence with Weber’s law. Similarly, the variability of maximal grip apertures in grasp demonstration approached significance in adherence with Weber’s law. In grasp control, the variability of maximal grip apertures did not increase with object size, which seems to violate Weber’s law. However, unlike in direct grasping, motion trajectories were prolonged and fragmented, and included an atypical waiting period prior to finger closure. Therefore, in

  6. Model-based automatic generation of grasping regions

    Science.gov (United States)

    Bloss, David A.

    1993-01-01

    The problem of automatically generating stable regions for a robotic end effector on a target object, given a model of the end effector and the object is discussed. In order to generate grasping regions, an initial valid grasp transformation from the end effector to the object is obtained based on form closure requirements, and appropriate rotational and translational symmetries are associated with that transformation in order to construct a valid, continuous grasping region. The main result of this algorithm is a list of specific, valid grasp transformations of the end effector to the target object, and the appropriate combinations of translational and rotational symmetries associated with each specific transformation in order to produce a continuous grasp region.

  7. Fast Grasp Contact Computation for a Serial Robot

    Science.gov (United States)

    Shi, Jianying (Inventor); Hargrave, Brian (Inventor); Diftler, Myron A. (Inventor)

    2015-01-01

    A system includes a controller and a serial robot having links that are interconnected by a joint, wherein the robot can grasp a three-dimensional (3D) object in response to a commanded grasp pose. The controller receives input information, including the commanded grasp pose, a first set of information describing the kinematics of the robot, and a second set of information describing the position of the object to be grasped. The controller also calculates, in a two-dimensional (2D) plane, a set of contact points between the serial robot and a surface of the 3D object needed for the serial robot to achieve the commanded grasp pose. A required joint angle is then calculated in the 2D plane between the pair of links using the set of contact points. A control action is then executed with respect to the motion of the serial robot using the required joint angle.

  8. Grasp Assist Device with Automatic Mode Control Logic

    Science.gov (United States)

    Davis, Donald R. (Inventor); Ihrke, Chris A. (Inventor); Laske, Evan (Inventor)

    2018-01-01

    A system includes a glove, sensors, actuator assemblies, and controller. The sensors include load sensors which measure an actual grasping force and attitude sensors which determine a glove attitude. The actuator assembly provides a grasp assist force to the glove. Respective locations of work cells in the work environment and permitted work tasks for each work cell are programmed into the controller. The controller detects the glove location and attitude. A work task is selected by the controller for the location. The controller calculates a required grasp assist force using measured actual grasping forces from the load sensors. The required grasp assist force is applied via the glove using the actuator assembly to thereby assist the operator in performing the identified work task.

  9. Key concepts and principles that explain changes in the provision of supports for intellectual and developmental disabilities in Spain

    Directory of Open Access Journals (Sweden)

    Miguel Ángel VERDUGO ALONSO

    2018-03-01

    Full Text Available The study focuses on the analysis of the central concepts that are influencing changes and transformations in the role of professionals and in the work done by organizations supporting people with intellectual and developmental disabilities in Spain. This includes the need for a global and systematic approach to the needs of the person, highlighting the importance of evidence to support professional, organizations and administrations decisions, and the influence that different systems (individual, family, organizational and social have in the life of the person. Finally, some conclusions are presented about the current moment and the immediate future.

  10. Legal frameworks and key concepts regulating diversion and treatment of mentally disordered offenders in European Union member states.

    Science.gov (United States)

    Dressing, Harald; Salize, Hans Joachim; Gordon, Harvey

    2007-10-01

    There is only limited research on the various legal regulations governing assessment, placement and treatment of mentally ill offenders in European Union member states (EU-member states). To provide a structured description and cross-boundary comparison of legal frameworks regulating diversion and treatment of mentally disordered offenders in EU-member states before the extension in May 2004. A special focus is on the concept of criminal responsibility. Information on legislation and practice concerning the assessment, placement and treatment of mentally ill offenders was gathered by means of a detailed, structured questionnaire which was filled in by national experts. The legal regulations relevant for forensic psychiatry in EU-member states are outlined. Definitions of mental disorders given within these acts are introduced and compared with ICD-10 diagnoses. Finally the application of the concept of criminal responsibility by the law and in routine practice is presented. Legal frameworks for the processing and placement of mentally disordered offenders varied markedly across EU-member states. Since May 2004 the European Union has expanded to 25 member states and in January 2007 it will reach 27. With increasing mobility across Europe, the need for increasing trans-national co-operation is becoming apparent in which great variation in legal tradition pertains.

  11. Collision-Avoidance Characteristics of Grasping. Early Signs in Hand and Arm Kinematics

    NARCIS (Netherlands)

    Lommertzen, J.; Costa e Silva, E.; Meulenbroek, R.G.J.

    2009-01-01

    Grasping an object successfully implies avoiding colliding into it before the hand is closed around the object. The present study focuses on prehension kinematics that typically reflect collision-avoidance characteristics of grasping movements. Twelve participants repeatedly grasped

  12. Value as the key concept in the health care system: how it has influenced medical practice and clinical decision-making processes.

    Science.gov (United States)

    Marzorati, Chiara; Pravettoni, Gabriella

    2017-01-01

    In the last 10 years, value has played a key role in the health care system. In this concept, innovations in medical practice and the increasing importance of patient centeredness have contributed to draw the attention of the medical community. Nonetheless, a large consensus on the meaning of "value" is still lacking: patients, physicians, policy makers, and other health care professionals have different ideas on which component of value may play a prominent role. Yet, shared clinical decision-making and patient empowerment have been recognized as fundamental features of the concept of value. Different paradigms of health care system embrace different meanings of value, and the absence of common and widely accepted definition does not help to identify a unique model of care in health care system. Our aim is to provide an overview of those paradigms that have considered value as a key theoretical concept and to investigate how the presence of value can influence the medical practice. This article may contribute to draw attention toward patients and propose a possible link between health care system based on "value" and new paradigms such as patient-centered system (PCS), patient empowerment, and P5 medicine, in order to create a predictive, personalized, preventive, participatory, and psycho-cognitive model to treat patients. Indeed, patient empowerment, value-based system, and P5 medicine seem to shed light on different aspects of a PCS, and this allows a better understanding of people under care.

  13. Decentral power stores. Key components of future power supply concepts; Dezentrale Energiespeicher. Schluesselkomponenten fuer die Stromversorgung der Zukunft

    Energy Technology Data Exchange (ETDEWEB)

    Huschke, Reinhard

    2011-07-01

    The book presents the most relevant power storage technologies, i.e. their advantages, shortcomings and possible applications. The focus is on decentral power stores that can be used wherever electric power must be stored, independent of local conditions. Although this concept does not play much of a role today, it will become more relevant in the context of increasingly decentral power supply. For 2020, a minimum share of 30 percent renewable energy in German power supply is required by law, while other scenarios assume an even bigger share. The present storage reserve capacity will not be sufficient for this. The book also goes into the applications of power storage systems in the fields of electromobility and in future, more decentral power grids. (orig.)

  14. Academic motivation, self-concept, engagement, and performance in high school: key processes from a longitudinal perspective.

    Science.gov (United States)

    Green, Jasmine; Liem, Gregory Arief D; Martin, Andrew J; Colmar, Susan; Marsh, Herbert W; McInerney, Dennis

    2012-10-01

    The study tested three theoretically/conceptually hypothesized longitudinal models of academic processes leading to academic performance. Based on a longitudinal sample of 1866 high-school students across two consecutive years of high school (Time 1 and Time 2), the model with the most superior heuristic value demonstrated: (a) academic motivation and self-concept positively predicted attitudes toward school; (b) attitudes toward school positively predicted class participation and homework completion and negatively predicted absenteeism; and (c) class participation and homework completion positively predicted test performance whilst absenteeism negatively predicted test performance. Taken together, these findings provide support for the relevance of the self-system model and, particularly, the importance of examining the dynamic relationships amongst engagement factors of the model. The study highlights implications for educational and psychological theory, measurement, and intervention. Copyright © 2012 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

  15. KEY ISSUES OF CONCEPTS' FORMATION OF THE NETWORK OF RESOURCE CENTER OF DISTANCE EDUCATION OF GENERAL EDUCATION INSTITUTIONS

    Directory of Open Access Journals (Sweden)

    Yuriy M. Bogachkov

    2013-06-01

    Full Text Available In the article the problem of constructing a network of resource centers for Distance Education to meet the needs of general secondary schools is presented. Modern educational trends in the use of Internet services in education are viewed.  Main contradictions, solution of which helps to create a network of resource centers, are identified. The definition of key terms related to the range of issues are given. The basic categories of participants, who  implementation of e-learning and networking are oriented on. There are considered the basic tasks of  distance education resource centers' functioning and types of supporting: personnel, regulatory, informative, systematic and  technical etc. The review of possible models of implementation of  students' distance education is reviewed . Three options for business models of resource centers, depending on funding  sources are offered.

  16. Robot Grasp Learning by Demonstration without Predefined Rules

    Directory of Open Access Journals (Sweden)

    César Fernández

    2011-12-01

    Full Text Available A learning-based approach to autonomous robot grasping is presented. Pattern recognition techniques are used to measure the similarity between a set of previously stored example grasps and all the possible candidate grasps for a new object. Two sets of features are defined in order to characterize grasps: point attributes describe the surroundings of a contact point; point-set attributes describe the relationship between the set of n contact points (assuming an n-fingered robot gripper is used. In the experiments performed, the nearest neighbour classifier outperforms other approaches like multilayer perceptrons, radial basis functions or decision trees, in terms of classification accuracy, while computational load is not excessive for a real time application (a grasp is fully synthesized in 0.2 seconds. The results obtained on a synthetic database show that the proposed system is able to imitate the grasping behaviour of the user (e.g. the system learns to grasp a mug by its handle. All the code has been made available for testing purposes.

  17. Attention and reach-to-grasp movements in Parkinson's disease.

    Science.gov (United States)

    Lu, Cathy; Bharmal, Aamir; Kiss, Zelma H; Suchowersky, Oksana; Haffenden, Angela M

    2010-08-01

    The role of attention in grasping movements directed at common objects has not been examined in Parkinson's disease (PD), though these movements are critical to activities of daily living. Our primary objective was to determine whether patients with PD demonstrate automaticity in grasping movements directed toward common objects. Automaticity is assumed when tasks can be performed with little or no interference from concurrent tasks. Grasping performance in three patient groups (newly diagnosed, moderate, and advanced/surgically treated PD) on and off of their medication or deep brain stimulation was compared to performance in an age-matched control group. Automaticity was demonstrated by the absence of a decrement in grasping performance when attention was consumed by a concurrent spatial-visualization task. Only the control group and newly diagnosed PD group demonstrated automaticity in their grasping movements. The moderate and advanced PD groups did not demonstrate automaticity. Furthermore, the well-known effects of pharmacotherapy and surgical intervention on movement speed and muscle activation patterns did not appear to reduce the impact of attention-demanding tasks on grasping movements in those with moderate to advanced PD. By the moderate stage of PD, grasping is an attention-demanding process; this change is not ameliorated by dopaminergic or surgical treatments. These findings have important implications for activities of daily living, as devoting attention to the simplest of daily tasks would interfere with complex activities and potentially exacerbate fatigue.

  18. A primer on brain-machine interfaces, concepts, and technology: a key element in the future of functional neurorestoration.

    Science.gov (United States)

    Lee, Brian; Liu, Charles Y; Apuzzo, Michael L J

    2013-01-01

    Conventionally, the practice of neurosurgery has been characterized by the removal of pathology, congenital or acquired. The emerging complement to the removal of pathology is surgery for the specific purpose of restoration of function. Advents in neuroscience, technology, and the understanding of neural circuitry are creating opportunities to intervene in disease processes in a reparative manner, thereby advancing toward the long-sought-after concept of neurorestoration. Approaching the issue of neurorestoration from a biomedical engineering perspective is the rapidly growing arena of implantable devices. Implantable devices are becoming more common in medicine and are making significant advancements to improve a patient's functional outcome. Devices such as deep brain stimulators, vagus nerve stimulators, and spinal cord stimulators are now becoming more commonplace in neurosurgery as we utilize our understanding of the nervous system to interpret neural activity and restore function. One of the most exciting prospects in neurosurgery is the technologically driven field of brain-machine interface, also known as brain-computer interface, or neuroprosthetics. The successful development of this technology will have far-reaching implications for patients suffering from a great number of diseases, including but not limited to spinal cord injury, paralysis, stroke, or loss of limb. This article provides an overview of the issues related to neurorestoration using implantable devices with a specific focus on brain-machine interface technology. Copyright © 2013 Elsevier Inc. All rights reserved.

  19. Grasping devices and methods in automated production processes

    DEFF Research Database (Denmark)

    Fantoni, Gualtiero; Santochi, Marco; Dini, Gino

    2014-01-01

    assembly to disassembly, from aerospace to food industry, from textile to logistics) are discussed. Finally, the most recent research is reviewed in order to introduce the new trends in grasping. They provide an outlook on the future of both grippers and robotic hands in automated production processes. (C......In automated production processes grasping devices and methods play a crucial role in the handling of many parts, components and products. This keynote paper starts with a classification of grasping phases, describes how different principles are adopted at different scales in different applications...

  20. Modeling and Simulation of Grasping of Deformable Objects

    DEFF Research Database (Denmark)

    Fugl, Andreas Rune

    Automated robot solutions have for decades been increasing productivity around the world. They are attractive for being fast, accurate and able to work in dangerous and repetitive environments. In traditional applications the grasped object is kinematically attached to the Tool Center Point....... The purpose of this thesis is to address the modeling and simulation of deformable objects, as applied to robotic grasping and manipulation. The main contributions of this work are: An evaluation of 3D linear elasticity used for robot grasping as implemented by a Finite Difference Method supporting regular...

  1. Learning Objects and Grasp Affordances through Autonomous Exploration

    DEFF Research Database (Denmark)

    Kraft, Dirk; Detry, Renaud; Pugeault, Nicolas

    2009-01-01

    We describe a system for autonomous learning of visual object representations and their grasp affordances on a robot-vision system. It segments objects by grasping and moving 3D scene features, and creates probabilistic visual representations for object detection, recognition and pose estimation...... image sequences as well as (3) a number of built-in behavioral modules on the one hand, and autonomous exploration on the other hand, the system is able to generate object and grasping knowledge through interaction with its environment....

  2. Understanding Key Mechanisms of Exercise-Induced Cardiac Protection to Mitigate Disease: Current Knowledge and Emerging Concepts.

    Science.gov (United States)

    Bernardo, Bianca C; Ooi, Jenny Y Y; Weeks, Kate L; Patterson, Natalie L; McMullen, Julie R

    2018-01-01

    The benefits of exercise on the heart are well recognized, and clinical studies have demonstrated that exercise is an intervention that can improve cardiac function in heart failure patients. This has led to significant research into understanding the key mechanisms responsible for exercise-induced cardiac protection. Here, we summarize molecular mechanisms that regulate exercise-induced cardiac myocyte growth and proliferation. We discuss in detail the effects of exercise on other cardiac cells, organelles, and systems that have received less or little attention and require further investigation. This includes cardiac excitation and contraction, mitochondrial adaptations, cellular stress responses to promote survival (heat shock response, ubiquitin-proteasome system, autophagy-lysosomal system, endoplasmic reticulum unfolded protein response, DNA damage response), extracellular matrix, inflammatory response, and organ-to-organ crosstalk. We summarize therapeutic strategies targeting known regulators of exercise-induced protection and the challenges translating findings from bench to bedside. We conclude that technological advancements that allow for in-depth profiling of the genome, transcriptome, proteome and metabolome, combined with animal and human studies, provide new opportunities for comprehensively defining the signaling and regulatory aspects of cell/organelle functions that underpin the protective properties of exercise. This is likely to lead to the identification of novel biomarkers and therapeutic targets for heart disease.

  3. The concept of transcortical cell assemblies: a key to the understanding of cortical lateralization and interhemispheric interaction.

    Science.gov (United States)

    Pulvermüller, F; Mohr, B

    1996-01-01

    According to Hebb, elements of higher cognitive processes, such as concepts, words and mental images, are realized in the brain as cortical cell assemblies, i.e. large and strongly connected neuron populations that form functional units. Neurons belonging to such assemblies may be scattered over wide cortical areas, and some cell assemblies may even comprise neurons of both hemispheres (transcortical assemblies). If full activation (ignition) of an assembly leads to fast circulation of neuronal activity in the assembly, this process should be visible in high-frequency cortical responses. Some evidence will be reviewed that cell assembly ignition indeed leads to changes in high-frequency cortical responses which can be recorded in the EEG and MEG. Within the cell assembly-framework, the question of cortical laterality translates into the question of how neurons of transcortical assemblies are balanced between the hemispheres. This approach allows for different degrees of laterality. Recent evidence is summarized that the degree of laterality indeed differs between language units. For example, the cortical representation of certain words appears to be strongly lateralized to the left hemisphere while those of others are less lateralized. If neurons of both hemispheres are part of one assembly bihemispheric processing should lead to a processing advantage compared to processing in the dominant hemisphere alone. The latter appears to be the case for lexical processing, as revealed by recent behavioral studies. In conclusion, the cell assembly-framework suggests a more fine-grained description of the issue of cortical laterality; it is not appropriate to ask whether "modules" supporting higher cortical functions are located either in the left or right hemisphere. Rather, it appears fruitful to ask how the neurons of transcortical cell assemblies are balanced between the hemispheres.

  4. Effect of pencil grasp on the speed and legibility of handwriting in children.

    Science.gov (United States)

    Schwellnus, Heidi; Carnahan, Heather; Kushki, Azadeh; Polatajko, Helene; Missiuna, Cheryl; Chau, Tom

    2012-01-01

    Pencil grasps other than the dynamic tripod may be functional for handwriting. This study examined the impact of grasp on handwriting speed and legibility. We videotaped 120 typically developing fourth-grade students while they performed a writing task. We categorized the grasps they used and evaluated their writing for speed and legibility using a handwriting assessment. Using linear regression analysis, we examined the relationship between grasp and handwriting. We documented six categories of pencil grasp: four mature grasp patterns, one immature grasp pattern, and one alternating grasp pattern. Multiple linear regression results revealed no significant effect for mature grasp on either legibility or speed. Pencil grasp patterns did not influence handwriting speed or legibility in this sample of typically developing children. This finding adds to the mounting body of evidence that alternative grasps may be acceptable for fast and legible handwriting. Copyright © 2012 by the American Occupational Therapy Association, Inc.

  5. Quantitative model of transport-aperture coordination during reach-to-grasp movements.

    Science.gov (United States)

    Rand, Miya K; Shimansky, Y P; Hossain, Abul B M I; Stelmach, George E

    2008-06-01

    It has been found in our previous studies that the initiation of aperture closure during reach-to-grasp movements occurs when the hand distance to target crosses a threshold that is a function of peak aperture amplitude, hand velocity, and hand acceleration. Thus, a stable relationship between those four movement parameters is observed at the moment of aperture closure initiation. Based on the concept of optimal control of movements (Naslin 1969) and its application for reach-to-grasp movement regulation (Hoff and Arbib 1993), it was hypothesized that the mathematical equation expressing that relationship can be generalized to describe coordination between hand transport and finger aperture during the entire reach-to-grasp movement by adding aperture velocity and acceleration to the above four movement parameters. The present study examines whether this hypothesis is supported by the data obtained in experiments in which young adults performed reach-to-grasp movements in eight combinations of two reach-amplitude conditions and four movement-speed conditions. It was found that linear approximation of the mathematical model described the relationship among the six movement parameters for the entire aperture-closure phase with very high precision for each condition, thus supporting the hypothesis for that phase. Testing whether one mathematical model could approximate the data across all the experimental conditions revealed that it was possible to achieve the same high level of data-fitting precision only by including in the model two additional, condition-encoding parameters and using a nonlinear, artificial neural network-based approximator with two hidden layers comprising three and two neurons, respectively. This result indicates that transport-aperture coordination, as a specific relationship between the parameters of hand transport and finger aperture, significantly depends on the condition-encoding variables. The data from the aperture-opening phase also fit a

  6. I metadati nelle biblioteche digitali: concetti chiave e prospettive Metadata issues in Digital Libraries: key concepts and perspectives

    Directory of Open Access Journals (Sweden)

    Iryna Solodovnik

    2011-12-01

    Full Text Available

    L'articolo si propone di esaminare il significato, il ruolo e le implicazioni di alcuni approcci utilizzati nella gestione della biblioteca digitale.

    L'innovazione nella gestione delle risorse online e il miglioramento della loro interoperabilità si può ottenere con una normalizzazione degli schemi di metadati attraverso l'uso di standard interoperabili e vocabolari internazionali e condivisi, e con l'arricchimento dato da ontologie e linked data, che sono alla base delle riflessioni sul web semantico e sulla costruzione di livelli semantici sulle descrizioni dei metadati.

    Attraverso l'esame di alcune metodologie innovative di rappresentazione dell'informazione (LODe-BD, SWAP, l'articolo mostra alcune modalità di creazione della conoscenza in ambiente digitale, con particolare riferimento ai dati bibliografici.

    The article sets out to investigate the meaning, role and implications of some information management approaches used in Digital Library practice. A greater focus on innovation in managing online resources and on improving their interoperability can be achieved by normalizing metadata schemas through interoperable standards, world-wide accepted controlled vocabularies as well as by their enrichment through qualitatively constructed ontologies and linked data, which are key to the expansion of the semantic reasoning on the web through building and connection of additional semantic layers on top of metadata descriptions. Reviewing some innovative methods of information representation (LODe-BD, SWAP, the paper tries to lead the reader to discover some new ways of knowledge creation in digital information environment, in particular what concerns digital bibliographic records.

  7. Modelling primate control of grasping for robotics applications

    CSIR Research Space (South Africa)

    Kleinhans, A

    2014-09-01

    Full Text Available The neural circuits that control grasping and perform related visual processing have been studied extensively in Macaque monkeys. We are developing a computational model of this system, in order to better understand its function, and to explore...

  8. The contributions of vision and haptics to reaching and grasping

    Directory of Open Access Journals (Sweden)

    Kayla Dawn Stone

    2015-09-01

    Full Text Available This review aims to provide a comprehensive outlook on the sensory (visual and haptic contributions to reaching and grasping. The focus is on studies in developing children, normal and neuropsychological populations, and in sensory-deprived individuals. Studies have suggested a right-hand/left-hemisphere specialization for visually-guided grasping and a left-hand/right-hemisphere specialization for haptically-guided object recognition. This poses the interesting possibility that when vision is not available and grasping relies heavily on the haptic system, there is an advantage to use the left hand. We review the evidence for this possibility and dissect the unique contributions of the visual and haptic systems to grasping. We ultimately discuss how the integration of these two sensory modalities shape hand preference.

  9. Value as the key concept in the health care system: how it has influenced medical practice and clinical decision-making processes

    Directory of Open Access Journals (Sweden)

    Marzorati C

    2017-03-01

    Full Text Available Chiara Marzorati,1,2 Gabriella Pravettoni2,3 1Foundations of the Life Sciences, Bioethics and Cognitive Science, European School of Molecular Medicine (SEMM, 2Applied Research Division for Cognitive and Psychological Science, European Institute of Oncology, 3Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy Abstract: In the last 10 years, value has played a key role in the health care system. In this concept, innovations in medical practice and the increasing importance of patient centeredness have contributed to draw the attention of the medical community. Nonetheless, a large consensus on the meaning of “value” is still lacking: patients, physicians, policy makers, and other health care professionals have different ideas on which component of value may play a prominent role. Yet, shared clinical decision-making and patient empowerment have been recognized as fundamental features of the concept of value. Different paradigms of health care system embrace different meanings of value, and the absence of common and widely accepted definition does not help to identify a unique model of care in health care system. Our aim is to provide an overview of those paradigms that have considered value as a key theoretical concept and to investigate how the presence of value can influence the medical practice. This article may contribute to draw attention toward patients and propose a possible link between health care system based on “value” and new paradigms such as patient-centered system (PCS, patient empowerment, and P5 medicine, in order to create a predictive, personalized, preventive, participatory, and psycho-cognitive model to treat patients. Indeed, patient empowerment, value-based system, and P5 medicine seem to shed light on different aspects of a PCS, and this allows a better understanding of people under care. Keywords: health care system, value, value-based medicine, patient empowerment, clinical decision

  10. Exploring manual asymmetries during grasping: a dynamic causal modeling approach.

    Directory of Open Access Journals (Sweden)

    Chiara eBegliomini

    2015-02-01

    Full Text Available Recording of neural activity during grasping actions in macaques showed that grasp-related sensorimotor transformations are accomplished in a circuit constituted by the anterior part of the intraparietal sulcus (AIP, the ventral (F5 and the dorsal (F2 region of the premotor area. In humans, neuroimaging studies have revealed the existence of a similar circuit, involving the putative homolog of macaque areas AIP, F5 and F2. These studies have mainly considered grasping movements performed with the right dominant hand and only a few studies have measured brain activity associated with a movement performed with the left non-dominant hand. As a consequence of this gap, how the brain controls for grasping movement performed with the dominant and the non-dominant hand still represents an open question. A functional resonance imaging experiment (fMRI has been conducted, and effective connectivity (Dynamic Causal Modelling, DCM was used to assess how connectivity among grasping-related areas is modulated by hand (i.e., left and right during the execution of grasping movements towards a small object requiring precision grasping. Results underlined boosted inter-hemispheric couplings between dorsal premotor cortices during the execution of movements performed with the left rather than the right dominant hand. More specifically, they suggest that the dorsal premotor cortices may play a fundamental role in monitoring the configuration of fingers when grasping movements are performed by either the right and the left hand. This role becomes particularly evident when the hand less-skilled (i.e., the left hand to perform such action is utilized. The results are discussed in light of recent theories put forward to explain how parieto-frontal connectivity is modulated by the execution of prehensile movements.

  11. Decoding natural reach-and-grasp actions from human EEG

    Science.gov (United States)

    Schwarz, Andreas; Ofner, Patrick; Pereira, Joana; Ioana Sburlea, Andreea; Müller-Putz, Gernot R.

    2018-02-01

    Objective. Despite the high number of degrees of freedom of the human hand, most actions of daily life can be executed incorporating only palmar, pincer and lateral grasp. In this study we attempt to discriminate these three different executed reach-and-grasp actions utilizing their EEG neural correlates. Approach. In a cue-guided experiment, 15 healthy individuals were asked to perform these actions using daily life objects. We recorded 72 trials for each reach-and-grasp condition and from a no-movement condition. Main results. Using low-frequency time domain features from 0.3 to 3 Hz, we achieved binary classification accuracies of 72.4%, STD  ±  5.8% between grasp types, for grasps versus no-movement condition peak performances of 93.5%, STD  ±  4.6% could be reached. In an offline multiclass classification scenario which incorporated not only all reach-and-grasp actions but also the no-movement condition, the highest performance could be reached using a window of 1000 ms for feature extraction. Classification performance peaked at 65.9%, STD  ±  8.1%. Underlying neural correlates of the reach-and-grasp actions, investigated over the primary motor cortex, showed significant differences starting from approximately 800 ms to 1200 ms after the movement onset which is also the same time frame where classification performance reached its maximum. Significance. We could show that it is possible to discriminate three executed reach-and-grasp actions prominent in people’s everyday use from non-invasive EEG. Underlying neural correlates showed significant differences between all tested conditions. These findings will eventually contribute to our attempt of controlling a neuroprosthesis in a natural and intuitive way, which could ultimately benefit motor impaired end users in their daily life actions.

  12. An Intelligent Inference System for Robot Hand Optimal Grasp Preshaping

    Directory of Open Access Journals (Sweden)

    Cabbar Veysel Baysal

    2010-11-01

    Full Text Available This paper presents a novel Intelligent Inference System (IIS for the determination of an optimum preshape for multifingered robot hand grasping, given object under a manipulation task. The IIS is formed as hybrid agent architecture, by the synthesis of object properties, manipulation task characteristics, grasp space partitioning, lowlevel kinematical analysis, evaluation of contact wrench patterns via fuzzy approximate reasoning and ANN structure for incremental learning. The IIS is implemented in software with a robot hand simulation.

  13. Grasping at ontological straws: overcoming reductionism in the Advaita Vedānta-Neuroscience dialogue.

    Science.gov (United States)

    Kaplan, Stephen

    2009-01-01

    Contemporary neuropsychology reveals that the parietal lobe contains neurons that are specifically attuned to the act of grasping and this act may be fundamental to the establishment of the phenomenal boundaries between subject and object. Furthermore, alterations to this process, such as the hypoactivation of this region during meditation or the hyperactivation associated with schizophrenia, may eliminate or confuse, respectively, the phenomenal boundaries between subject and object. Traversing disciplines, the Advaita Vedānta school of Hinduism traces some of its key terms for subject and object to the verbal root grah, to grasp. The subject is literally the grasper. Furthermore, the practice of asparśa yoga, the yoga of no-touch, is aimed at stopping, hypoactivating, the grasping process in order to transcend all subject-object boundaries. This paper will argue that while we have not uncovered an identity of thought, we have uncovered a confluence of ideas between these two disciplines. We will see that this confluence of ideas has not pitted the believer against the critic-not forced us into the great reductionism debate that has dominated so much of the interchange between religious studies and the sciences. This case study will illuminate some of the methodological ways around this reductionism battle and also the boundaries of both disciplines for the intellectual benefit of each.

  14. Improving comprehension and recall of information for an HIV vaccine trial among women at risk for HIV: reading level simplification and inclusion of pictures to illustrate key concepts.

    Science.gov (United States)

    Murphy, D A; O'Keefe, Z H; Kaufman, A H

    1999-10-01

    A simplified version of the prototype HIV vaccine material was developed through (a) reducing reading grade level, (b) restructuring of the organization and categorization of the material, (c) adding pictures designed to emphasize key concepts, and (d) obtaining feedback on the simplified version through focus groups with the target population. Low-income women at risk for HIV (N = 141) recruited from a primary care clinic were randomly assigned to be presented the standard or the simplified version. There were no significant differences between the groups in terms of education or Vocabulary, Block Design, and Passage Comprehension scores. Women who received the simplified version had significantly higher comprehension scores immediately following presentation of the material than did women who received the standard version and were also significantly more likely to recall study benefits and risks. These findings were maintained at 3-month follow-up. Implications for informed consent are discussed.

  15. General Rotorcraft Aeromechanical Stability Program (GRASP): Theory manual

    Science.gov (United States)

    Hodges, Dewey H.; Hopkins, A. Stewart; Kunz, Donald L.; Hinnant, Howard E.

    1990-01-01

    The general rotorcraft aeromechanical stability program (GRASP) was developed to calculate aeroelastic stability for rotorcraft in hovering flight, vertical flight, and ground contact conditions. GRASP is described in terms of its capabilities and its philosophy of modeling. The equations of motion that govern the physical system are described, as well as the analytical approximations used to derive them. The equations include the kinematical equation, the element equations, and the constraint equations. In addition, the solution procedures used by GRASP are described. GRASP is capable of treating the nonlinear static and linearized dynamic behavior of structures represented by arbitrary collections of rigid-body and beam elements. These elements may be connected in an arbitrary fashion, and are permitted to have large relative motions. The main limitation of this analysis is that periodic coefficient effects are not treated, restricting rotorcraft flight conditions to hover, axial flight, and ground contact. Instead of following the methods employed in other rotorcraft programs. GRASP is designed to be a hybrid of the finite-element method and the multibody methods used in spacecraft analysis. GRASP differs from traditional finite-element programs by allowing multiple levels of substructure in which the substructures can move and/or rotate relative to others with no small-angle approximations. This capability facilitates the modeling of rotorcraft structures, including the rotating/nonrotating interface and the details of the blade/root kinematics for various types. GRASP differs from traditional multibody programs by considering aeroelastic effects, including inflow dynamics (simple unsteady aerodynamics) and nonlinear aerodynamic coefficients.

  16. Preclosure probabilistic assessment of the Canadian concept for used fuel disposal focussing on key radionuclides and exposure pathways for routine emissions

    International Nuclear Information System (INIS)

    Russell, S.B.

    1996-01-01

    The Canadian Nuclear Fuel Waste Management Program was initiated in 1978 to develop a concept for safe disposal of nuclear fuel waste (intact used nuclear fuel or high-level waste from any future reprocessing of used fuel) from CANDU reactors. The concept includes the immobilization of nuclear fuel waste and emplacement of the waste in an engineered vault, deep underground in a stable rock formation within the Canadian Shield. In 1994, AECL submitted an environmental and safety assessment of the disposal concept in the form of an Environmental Impact Statement or EIS for regulatory, scientific and public reviews. Ontario Hydro's contribution to the EIS included the preclosure assessment consisting of the safety and environmental implications of the construction, operation and decommissioning (closure) of a conceptual used-fuel disposal centre (UFDC), plus transportation of used fuel from storage at reactor sites to the UFDC. In the EIS, the environmental impact from routine emissions from the UFDC during the operation phase was calculated in a deterministic mode using single-valued constants representing the geometric mean or the average value of the input parameters in the preclosure model PREAC (Preclosure Radiological Environmental Assessment Code). A qualitative estimate of the range of uncertainty associated with the preclosure model dose predictions was about an order of magnitude based on a review of the expected range of input parameter values. This paper examines the time-behaviour of the preclosure system and provides a quantitative estimate of the uncertainty, as determined through the use of probabilistic techniques, associated with the potential radiological impact from the same chronic UFDC radionuclide emissions during the preclosure phase. The individual dose to a member of the critical group assumed to be living near the UFDC has been assessed for selected key radionuclides and exposure pathways identified in the EIS. The purpose of this post

  17. Social risk, stigma and space: key concepts for understanding HIV vulnerability among black men who have sex with men in New York City.

    Science.gov (United States)

    Parker, Caroline M; Garcia, Jonathan; Philbin, Morgan M; Wilson, Patrick A; Parker, Richard G; Hirsch, Jennifer S

    2017-03-01

    Black men who have sex with men in the USA face disproportionate incidence rates of HIV. This paper presents findings from an ethnographic study conducted in New York City that explored the structural and socio-cultural factors shaping men's sexual relationships with the goal of furthering understandings of their HIV-related vulnerability. Methods included participant observation and in-depth interviews with 31 Black men who have sex with men (three times each) and 17 key informants. We found that HIV vulnerability is perceived as produced through structural inequalities including economic insecurity, housing instability, and stigma and discrimination. The theoretical concepts of social risk, intersectional stigma, and the social production of space are offered as lenses through which to analyse how structural inequalities shape HIV vulnerability. We found that social risk shaped HIV vulnerability by influencing men's decisions in four domains: 1) where to find sexual partners, 2) where to engage in sexual relationships, 3) what kinds of relationships to seek, and 4) whether to carry and to use condoms. Advancing conceptualisations of social risk, we show that intersectional stigma and the social production of space are key processes through which social risk generates HIV vulnerability among Black men who have sex with men.

  18. Brain Function Overlaps When People Observe Emblems, Speech, and Grasping

    Science.gov (United States)

    Andric, Michael; Solodkin, Ana; Buccino, Giovanni; Goldin-Meadow, Susan; Rizzolatti, Giacomo; Small, Steven L.

    2013-01-01

    A hand grasping a cup or gesturing ‘thumbs-up’, while both manual actions, have different purposes and effects. Grasping directly affects the cup, whereas gesturing ‘thumbs-up’ has an effect through an implied verbal (symbolic) meaning. Because grasping and emblematic gestures (‘emblems’) are both goal-oriented hand actions, we pursued the hypothesis that observing each should evoke similar activity in neural regions implicated in processing goal-oriented hand actions. However, because emblems express symbolic meaning, observing them should also evoke activity in regions implicated in interpreting meaning, which is most commonly expressed in language. Using fMRI to test this hypothesis, we had participants watch videos of an actor performing emblems, speaking utterances matched in meaning to the emblems, and grasping objects. Our results show that lateral temporal and inferior frontal regions respond to symbolic meaning, even when it is expressed by a single hand action. In particular, we found that left inferior frontal and right lateral temporal regions are strongly engaged when people observe either emblems or speech. In contrast, we also replicate and extend previous work that implicates parietal and premotor responses in observing goal-oriented hand actions. For hand actions, we found that bilateral parietal and premotor regions are strongly engaged when people observe either emblems or grasping. These findings thus characterize converging brain responses to shared features (e.g., symbolic or manual), despite their encoding and presentation in different stimulus modalities. PMID:23583968

  19. Toward autonomous avian-inspired grasping for micro aerial vehicles

    International Nuclear Information System (INIS)

    Thomas, Justin; Loianno, Giuseppe; Polin, Joseph; Kumar, Vijay; Sreenath, Koushil

    2014-01-01

    Micro aerial vehicles, particularly quadrotors, have been used in a wide range of applications. However, the literature on aerial manipulation and grasping is limited and the work is based on quasi-static models. In this paper, we draw inspiration from agile, fast-moving birds such as raptors, that are able to capture moving prey on the ground or in water, and develop similar capabilities for quadrotors. We address dynamic grasping, an approach to prehensile grasping in which the dynamics of the robot and its gripper are significant and must be explicitly modeled and controlled for successful execution. Dynamic grasping is relevant for fast pick-and-place operations, transportation and delivery of objects, and placing or retrieving sensors. We show how this capability can be realized (a) using a motion capture system and (b) without external sensors relying only on onboard sensors. In both cases we describe the dynamic model, and trajectory planning and control algorithms. In particular, we present a methodology for flying and grasping a cylindrical object using feedback from a monocular camera and an inertial measurement unit onboard the aerial robot. This is accomplished by mapping the dynamics of the quadrotor to a level virtual image plane, which in turn enables dynamically-feasible trajectory planning for image features in the image space, and a vision-based controller with guaranteed convergence properties. We also present experimental results obtained with a quadrotor equipped with an articulated gripper to illustrate both approaches. (papers)

  20. Toward autonomous avian-inspired grasping for micro aerial vehicles.

    Science.gov (United States)

    Thomas, Justin; Loianno, Giuseppe; Polin, Joseph; Sreenath, Koushil; Kumar, Vijay

    2014-06-01

    Micro aerial vehicles, particularly quadrotors, have been used in a wide range of applications. However, the literature on aerial manipulation and grasping is limited and the work is based on quasi-static models. In this paper, we draw inspiration from agile, fast-moving birds such as raptors, that are able to capture moving prey on the ground or in water, and develop similar capabilities for quadrotors. We address dynamic grasping, an approach to prehensile grasping in which the dynamics of the robot and its gripper are significant and must be explicitly modeled and controlled for successful execution. Dynamic grasping is relevant for fast pick-and-place operations, transportation and delivery of objects, and placing or retrieving sensors. We show how this capability can be realized (a) using a motion capture system and (b) without external sensors relying only on onboard sensors. In both cases we describe the dynamic model, and trajectory planning and control algorithms. In particular, we present a methodology for flying and grasping a cylindrical object using feedback from a monocular camera and an inertial measurement unit onboard the aerial robot. This is accomplished by mapping the dynamics of the quadrotor to a level virtual image plane, which in turn enables dynamically-feasible trajectory planning for image features in the image space, and a vision-based controller with guaranteed convergence properties. We also present experimental results obtained with a quadrotor equipped with an articulated gripper to illustrate both approaches.

  1. Kinematic characteristics of tenodesis grasp in C6 quadriplegia.

    Science.gov (United States)

    Mateo, S; Revol, P; Fourtassi, M; Rossetti, Y; Collet, C; Rode, G

    2013-02-01

    Descriptive control case study. To analyze the kinematics of tenodesis grasp in participants with C6 quadriplegia and healthy control participants in a pointing task and two daily life tasks involving a whole hand grip (apple) or a lateral grip (floppy disk). France. Four complete participants with C6 quadriplegia were age matched with four healthy control participants. All participants were right-handed. The measured kinematic parameters were the movement time (MT), the peak velocity (PV), the time of PV (TPV) and the wrist angle in the sagittal plane at movement onset, at the TPV and at the movement end point. The participants with C6 quadriplegia had significantly longer MTs in both prehension tasks. No significant differences in TPV were found between the two groups. Unlike control participants, for both prehension tasks the wrist of participants with C6 quadriplegia was in a neutral position at movement onset, in flexion at the TPV, and in extension at the movement end point. Two main kinematic parameters characterize tenodesis grasp movements in C6 quadriplegics: wrist flexion during reaching and wrist extension during the grasping phase, and increased MT reflecting the time required to adjust the wrist's position to achieve the tenodesis grasp. These characteristics were observed for two different grips (whole hand and lateral grip). These results suggest sequential planning of reaching and tenodesis grasp, and should be taken into account for prehension rehabilitation in patients with quadriplegia.

  2. Grasp movement decoding from premotor and parietal cortex.

    Science.gov (United States)

    Townsend, Benjamin R; Subasi, Erk; Scherberger, Hansjörg

    2011-10-05

    Despite recent advances in harnessing cortical motor-related activity to control computer cursors and robotic devices, the ability to decode and execute different grasping patterns remains a major obstacle. Here we demonstrate a simple Bayesian decoder for real-time classification of grip type and wrist orientation in macaque monkeys that uses higher-order planning signals from anterior intraparietal cortex (AIP) and ventral premotor cortex (area F5). Real-time decoding was based on multiunit signals, which had similar tuning properties to cells in previous single-unit recording studies. Maximum decoding accuracy for two grasp types (power and precision grip) and five wrist orientations was 63% (chance level, 10%). Analysis of decoder performance showed that grip type decoding was highly accurate (90.6%), with most errors occurring during orientation classification. In a subsequent off-line analysis, we found small but significant performance improvements (mean, 6.25 percentage points) when using an optimized spike-sorting method (superparamagnetic clustering). Furthermore, we observed significant differences in the contributions of F5 and AIP for grasp decoding, with F5 being better suited for classification of the grip type and AIP contributing more toward decoding of object orientation. However, optimum decoding performance was maximal when using neural activity simultaneously from both areas. Overall, these results highlight quantitative differences in the functional representation of grasp movements in AIP and F5 and represent a first step toward using these signals for developing functional neural interfaces for hand grasping.

  3. Brain function overlaps when people observe emblems, speech, and grasping.

    Science.gov (United States)

    Andric, Michael; Solodkin, Ana; Buccino, Giovanni; Goldin-Meadow, Susan; Rizzolatti, Giacomo; Small, Steven L

    2013-07-01

    A hand grasping a cup or gesturing "thumbs-up", while both manual actions, have different purposes and effects. Grasping directly affects the cup, whereas gesturing "thumbs-up" has an effect through an implied verbal (symbolic) meaning. Because grasping and emblematic gestures ("emblems") are both goal-oriented hand actions, we pursued the hypothesis that observing each should evoke similar activity in neural regions implicated in processing goal-oriented hand actions. However, because emblems express symbolic meaning, observing them should also evoke activity in regions implicated in interpreting meaning, which is most commonly expressed in language. Using fMRI to test this hypothesis, we had participants watch videos of an actor performing emblems, speaking utterances matched in meaning to the emblems, and grasping objects. Our results show that lateral temporal and inferior frontal regions respond to symbolic meaning, even when it is expressed by a single hand action. In particular, we found that left inferior frontal and right lateral temporal regions are strongly engaged when people observe either emblems or speech. In contrast, we also replicate and extend previous work that implicates parietal and premotor responses in observing goal-oriented hand actions. For hand actions, we found that bilateral parietal and premotor regions are strongly engaged when people observe either emblems or grasping. These findings thus characterize converging brain responses to shared features (e.g., symbolic or manual), despite their encoding and presentation in different stimulus modalities. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. ModGrasp: An open-source rapid-prototyping framework for designing low-cost sensorised modular hands

    OpenAIRE

    Sanfilippo, Filippo; Zhang, Houxiang; Pettersen, Kristin Ytterstad; Salvietti, G.; Prattichizzo, Domenico

    2014-01-01

    This paper introduces ModGrasp, an open-source virtual and physical rapid-prototyping framework that allows for the design, simulation and control of low-cost sensorised modular hands. By combining the rapid-prototyping approach with the modular concept, different manipulator configurations can be modelled. A real-time one-to-one correspondence between virtual and physical prototypes is established. Different control algorithms can be implemented for the models. By using a low-cost sensing ap...

  5. Mena–GRASP65 interaction couples actin polymerization to Golgi ribbon linking

    Science.gov (United States)

    Tang, Danming; Zhang, Xiaoyan; Huang, Shijiao; Yuan, Hebao; Li, Jie; Wang, Yanzhuang

    2016-01-01

    In mammalian cells, the Golgi reassembly stacking protein 65 (GRASP65) has been implicated in both Golgi stacking and ribbon linking by forming trans-oligomers through the N-terminal GRASP domain. Because the GRASP domain is globular and relatively small, but the gaps between stacks are large and heterogeneous, it remains puzzling how GRASP65 physically links Golgi stacks into a ribbon. To explore the possibility that other proteins may help GRASP65 in ribbon linking, we used biochemical methods and identified the actin elongation factor Mena as a novel GRASP65-binding protein. Mena is recruited onto the Golgi membranes through interaction with GRASP65. Depleting Mena or disrupting actin polymerization resulted in Golgi fragmentation. In cells, Mena and actin were required for Golgi ribbon formation after nocodazole washout; in vitro, Mena and microfilaments enhanced GRASP65 oligomerization and Golgi membrane fusion. Thus Mena interacts with GRASP65 to promote local actin polymerization, which facilitates Golgi ribbon linking. PMID:26538023

  6. Application of a sensor fusion algorithm for improving grasping stability

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Hyeon; Yoon, Hyun Suck; Moon, Hyung Pil; Choi, Hyouk Ryeol; Koo Ja Choon [Sungkyunkwan University, Suwon (Korea, Republic of)

    2015-07-15

    A robot hand normally employees various sensors that are packaged in small form factor, perform with delicately accurate, and cost mostly very expensive. Grasping operation of the hand relies especially on accuracy of those sensors. Even with a set of advanced sensory systems embedded in a robot hand, securing a stable grasping is still challenging task. The present work makes an attempt to improve force sensor accuracy by applying sensor fusion method. An optimal weight value sensor fusion method formulated with Kalman filters is presented and tested in the work. Using a set of inexpensive sensors, the work achieves a reliable force sensing and applies the enhanced sensor stability to an object pinch grasping.

  7. Application of a sensor fusion algorithm for improving grasping stability

    International Nuclear Information System (INIS)

    Kim, Jae Hyeon; Yoon, Hyun Suck; Moon, Hyung Pil; Choi, Hyouk Ryeol; Koo Ja Choon

    2015-01-01

    A robot hand normally employees various sensors that are packaged in small form factor, perform with delicately accurate, and cost mostly very expensive. Grasping operation of the hand relies especially on accuracy of those sensors. Even with a set of advanced sensory systems embedded in a robot hand, securing a stable grasping is still challenging task. The present work makes an attempt to improve force sensor accuracy by applying sensor fusion method. An optimal weight value sensor fusion method formulated with Kalman filters is presented and tested in the work. Using a set of inexpensive sensors, the work achieves a reliable force sensing and applies the enhanced sensor stability to an object pinch grasping.

  8. Grasping convergent evolution in syngnathids: a unique tale of tails

    Science.gov (United States)

    Neutens, C; Adriaens, D; Christiaens, J; De Kegel, B; Dierick, M; Boistel, R; Van Hoorebeke, L

    2014-01-01

    Seahorses and pipehorses both possess a prehensile tail, a unique characteristic among teleost fishes, allowing them to grasp and hold onto substrates such as sea grasses. Although studies have focused on tail grasping, the pattern of evolutionary transformations that made this possible is poorly understood. Recent phylogenetic studies show that the prehensile tail evolved independently in different syngnathid lineages, including seahorses, Haliichthys taeniophorus and several types of so-called pipehorses. This study explores the pattern that characterizes this convergent evolution towards a prehensile tail, by comparing the caudal musculoskeletal organization, as well as passive bending capacities in pipefish (representing the ancestral state), pipehorse, seahorse and H. taeniophorus. To study the complex musculoskeletal morphology, histological sectioning, μCT-scanning and phase contrast synchrotron scanning were combined with virtual 3D-reconstructions. Results suggest that the independent evolution towards tail grasping in syngnathids reflects at least two quite different strategies in which the ancestral condition of a heavy plated and rigid system became modified into a highly flexible one. Intermediate skeletal morphologies (between the ancestral condition and seahorses) could be found in the pygmy pipehorses and H. taeniophorus, which are phylogenetically closely affiliated with seahorses. This study suggests that the characteristic parallel myoseptal organization as already described in seahorse (compared with a conical organization in pipefish and pipehorse) may not be a necessity for grasping, but represents an apomorphy for seahorses, as this pattern is not found in other syngnathid species possessing a prehensile tail. One could suggest that the functionality of grasping evolved before the specialized, parallel myoseptal organization seen in seahorses. However, as the grasping system in pipehorses is a totally different one, this cannot be

  9. Ground Robotic Hand Applications for the Space Program study (GRASP)

    Science.gov (United States)

    Grissom, William A.; Rafla, Nader I. (Editor)

    1992-01-01

    This document reports on a NASA-STDP effort to address research interests of the NASA Kennedy Space Center (KSC) through a study entitled, Ground Robotic-Hand Applications for the Space Program (GRASP). The primary objective of the GRASP study was to identify beneficial applications of specialized end-effectors and robotic hand devices for automating any ground operations which are performed at the Kennedy Space Center. Thus, operations for expendable vehicles, the Space Shuttle and its components, and all payloads were included in the study. Typical benefits of automating operations, or augmenting human operators performing physical tasks, include: reduced costs; enhanced safety and reliability; and reduced processing turnaround time.

  10. Software engineering capability for Ada (GRASP/Ada Tool)

    Science.gov (United States)

    Cross, James H., II

    1995-01-01

    The GRASP/Ada project (Graphical Representations of Algorithms, Structures, and Processes for Ada) has successfully created and prototyped a new algorithmic level graphical representation for Ada software, the Control Structure Diagram (CSD). The primary impetus for creation of the CSD was to improve the comprehension efficiency of Ada software and, as a result, improve reliability and reduce costs. The emphasis has been on the automatic generation of the CSD from Ada PDL or source code to support reverse engineering and maintenance. The CSD has the potential to replace traditional prettyprinted Ada Source code. A new Motif compliant graphical user interface has been developed for the GRASP/Ada prototype.

  11. Establishing a library of resources to help people understand key concepts in assessing treatment claims-The "Critical thinking and Appraisal Resource Library" (CARL).

    Science.gov (United States)

    Castle, John C; Chalmers, Iain; Atkinson, Patricia; Badenoch, Douglas; Oxman, Andrew D; Austvoll-Dahlgren, Astrid; Nordheim, Lena; Krause, L Kendall; Schwartz, Lisa M; Woloshin, Steven; Burls, Amanda; Mosconi, Paola; Hoffmann, Tammy; Cusack, Leila; Albarqouni, Loai; Glasziou, Paul

    2017-01-01

    People are frequently confronted with untrustworthy claims about the effects of treatments. Uncritical acceptance of these claims can lead to poor, and sometimes dangerous, treatment decisions, and wasted time and money. Resources to help people learn to think critically about treatment claims are scarce, and they are widely scattered. Furthermore, very few learning-resources have been assessed to see if they improve knowledge and behavior. Our objectives were to develop the Critical thinking and Appraisal Resource Library (CARL). This library was to be in the form of a database containing learning resources for those who are responsible for encouraging critical thinking about treatment claims, and was to be made available online. We wished to include resources for groups we identified as 'intermediaries' of knowledge, i.e. teachers of schoolchildren, undergraduates and graduates, for example those teaching evidence-based medicine, or those communicating treatment claims to the public. In selecting resources, we wished to draw particular attention to those resources that had been formally evaluated, for example, by the creators of the resource or independent research groups. CARL was populated with learning-resources identified from a variety of sources-two previously developed but unmaintained inventories; systematic reviews of learning-interventions; online and database searches; and recommendations by members of the project group and its advisors. The learning-resources in CARL were organised by 'Key Concepts' needed to judge the trustworthiness of treatment claims, and were made available online by the James Lind Initiative in Testing Treatments interactive (TTi) English (www.testingtreatments.org/category/learning-resources).TTi English also incorporated the database of Key Concepts and the Claim Evaluation Tools developed through the Informed Healthcare Choices (IHC) project (informedhealthchoices.org). We have created a database of resources called CARL

  12. A proof-of-concept model for the identification of the key events in the infection process with specific reference to Pseudomonas aeruginosa in corneal infections

    Directory of Open Access Journals (Sweden)

    Ilias Soumpasis

    2015-11-01

    Full Text Available Background: It is a common medical practice to characterise an infection based on the causative agent and to adopt therapeutic and prevention strategies targeting the agent itself. However, from an epidemiological perspective, exposure to a microbe can be harmless to a host as a result of low-level exposure or due to host immune response, with opportunistic infection only occurring as a result of changes in the host, pathogen, or surrounding environment. Methods: We have attempted to review systematically the key host, pathogen, and environmental factors that may significantly impact clinical outcomes of exposure to a pathogen, using Pseudomonas aeruginosa eye infection as a case study. Results and discussion: Extended contact lens wearing and compromised hygiene may predispose users to microbial keratitis, which can be a severe and vision-threatening infection. P. aeruginosa has a wide array of virulence-associated genes and sensing systems to initiate and maintain cell populations at the corneal surface and beyond. We have adapted the well-known concept of the epidemiological triangle in combination with the classic risk assessment framework (hazard identification, characterisation, and exposure to develop a conceptual pathway-based model that demonstrates the overlapping relationships between the host, the pathogen, and the environment; and to illustrate the key events in P. aeruginosa eye infection. Conclusion: This strategy differs from traditional approaches that consider potential risk factors in isolation, and hopefully will aid the identification of data and models to inform preventive and therapeutic measures in addition to risk assessment. Furthermore, this may facilitate the identification of knowledge gaps to direct research in areas of greatest impact to avert or mitigate adverse outcomes of infection.

  13. TMS over the supramarginal gyrus delays selection of appropriate grasp orientation during reaching and grasping tools for use.

    Science.gov (United States)

    McDowell, Tomás; Holmes, Nicholas P; Sunderland, Alan; Schürmann, Martin

    2018-03-09

    Tool use, a ubiquitous part of human behaviour, requires manipulation control and knowledge of tool purpose. Neuroimaging and neuropsychological research posit that these two processes are supported by separate brain regions, ventral premotor and inferior parietal for manipulation control, and posterior middle temporal cortex for tool knowledge, lateralised to the left hemisphere. Action plans for tool use need to integrate these two separate processes, which is likely supported by the left supramarginal gyrus (SMG). However, whether this integration occurs during action execution is not known. To clarify the role of the SMG we conducted two experiments in which healthy participants reached to grasp everyday tools with the explicit instruction to use them directly following their grasp. To study the integration of manipulation control and tool knowledge within a narrow time window we mechanically perturbed the orientation of the tool to force participants to correct grasp orientation 'on-line' during the reaching movement. In experiment 1, twenty healthy participants reached with their left hand to grasp a tool. Double-pulse transcranial magnetic stimulation (TMS) was applied, in different blocks over left or right SMG at the onset of perturbation. Kinematic data revealed delayed and erroneous online correction after TMS over left and right SMG. In Experiment 2 twelve participants reached, in different blocks, with their left or right hand and TMS was applied over SMG ipsilateral to the reaching hand. A similar effect on correction was observed for ipsilateral stimulation when reaching with the left and right hands, and no effect of or interaction with hemisphere was observed. Our findings implicate a bilateral role of the SMG in correcting movements and selection of appropriate grasp orientation during reaching to grasp tools for use. Copyright © 2018 Elsevier Ltd. All rights reserved.

  14. Development of prosthesis grasp control systems on a robotic testbed

    NARCIS (Netherlands)

    Peerdeman, B.; Fabrizi, Ugo; Palli, Gianluca; Melchiorri, Claudio; Stramigioli, Stefano; Misra, Sarthak

    2012-01-01

    Modern myoelectric hand prostheses continue to increase in functionality, while their control is constrained by the limits of myoelectric input. This paper covers the development and testing of grasp control systems for multifunctional myoelectric prosthetic hands. The functionality of modern hand

  15. Hand Preference for Precision Grasping Predicts Language Lateralization

    Science.gov (United States)

    Gonzalez, Claudia L. R.; Goodale, Melvyn A.

    2009-01-01

    We investigated whether or not there is a relationship between hand preference for grasping and hemispheric dominance for language--and how each of these is related to other traditional measures of handedness. To do this we asked right- and left-handed participants to put together two different sets of 3D puzzles made out of big or very small…

  16. Improvement and Neuroplasticity after Combined Rehabilitation to Forced Grasping

    Directory of Open Access Journals (Sweden)

    Michiko Arima

    2017-01-01

    Full Text Available The grasp reflex is a distressing symptom but the need to treat or suppress it has rarely been discussed in the literature. We report the case of a 17-year-old man who had suffered cerebral infarction of the right putamen and temporal lobe 10 years previously. Forced grasping of the hemiparetic left upper limb was improved after a unique combined treatment. Botulinum toxin type A (BTX-A was first injected into the left biceps, wrist flexor muscles, and finger flexor muscles. Forced grasping was reduced along with spasticity of the upper limb. In addition, repetitive facilitative exercise and object-related training were performed under low-amplitude continuous neuromuscular electrical stimulation. Since this 2-week treatment improved upper limb function, we compared brain activities, as measured by near-infrared spectroscopy during finger pinching, before and after the combined treatment. Brain activities in the ipsilesional sensorimotor cortex (SMC and medial frontal cortex (MFC during pinching under electrical stimulation after treatment were greater than those before. The results suggest that training under electrical stimulation after BTX-A treatment may modulate the activities of the ipsilesional SMC and MFC and lead to functional improvement of the affected upper limb with forced grasping.

  17. Modeling the shape hierarchy for visually guided grasping

    CSIR Research Space (South Africa)

    Rezai, O

    2014-10-01

    Full Text Available The monkey anterior intraparietal area (AIP) encodes visual information about three-dimensional object shape that is used to shape the hand for grasping. We modeled shape tuning in visual AIP neurons and its relationship with curvature and gradient...

  18. Task Requirements Influence Sensory Integration during Grasping in Humans

    Science.gov (United States)

    Safstrom, Daniel; Edin, Benoni B.

    2004-01-01

    The sensorimotor transformations necessary for generating appropriate motor commands depend on both current and previously acquired sensory information. To investigate the relative impact (or weighting) of visual and haptic information about object size during grasping movements, we let normal subjects perform a task in which, unbeknownst to the…

  19. Saccadic updating of object orientation for grasping movements

    NARCIS (Netherlands)

    Selen, L.P.J.; Medendorp, W.P.

    2011-01-01

    Reach and grasp movements are a fundamental part of our daily interactions with the environment. This spatially-guided behavior is often directed to memorized objects because of intervening eye movements that caused them to disappear from sight. How does the brain store and maintain the spatial

  20. Development of Object and Grasping Knowledge by Robot Exploration

    DEFF Research Database (Denmark)

    Kraft, Dirk; Detry, Renaud; Pugeault, Nicolas

    2010-01-01

    We describe a bootstrapping cognitive robot system that—mainly based on pure exploration—acquires rich object representations and associated object-specific grasp affordances. Such bootstrapping becomes possible by combining innate competences and behaviours by which the system gradually enriches...

  1. Grasping an object comfortably: orientation information is held in memory

    NARCIS (Netherlands)

    Roche, K; Verheij, R.; Voudouris, D.; Chainay, H.; Smeets, J.B.J.

    2015-01-01

    It has been shown that memorized information can influence real-time visuomotor control. For instance, a previously seen object (prime) influences grasping movements toward a target object. In this study, we examined how general the priming effect is: does it depend on the orientation of the target

  2. The Sliced Pineapple Grid Feature for Predicting Grasping Affordances

    DEFF Research Database (Denmark)

    Thomsen, Mikkel Tang; Kraft, Dirk; Krüger, Norbert

    2017-01-01

    The problem of grasping unknown objects utilising vision is addressed in this work by introducing a novel feature, the Sliced Pineapple Grid Feature (SPGF). The SPGF encode semi-local surfaces and allows for distinguishing structures such as “walls”,“edges” and “rims”. These structures are shown...

  3. Vision-based autonomous grasping of unknown piled objects

    International Nuclear Information System (INIS)

    Johnson, R.K.

    1994-01-01

    Computer vision techniques have been used to develop a vision-based grasping capability for autonomously picking and placing unknown piled objects. This work is currently being applied to the problem of hazardous waste sorting in support of the Department of Energy's Mixed Waste Operations Program

  4. An electromyographic analysis of two handwriting grasp patterns.

    Science.gov (United States)

    de Almeida, Pedro Henrique Tavares Queiroz; da Cruz, Daniel Marinho Cezar; Magna, Luis Alberto; Ferrigno, Iracema Serrat Vergotti

    2013-08-01

    Handwriting is a fundamental skill needed for the development of daily-life activities during lifetime and can be performed using different forms to hold the writing object. In this study, we monitored the sEMG activity of trapezius, biceps brachii, extensor carpi radialis brevis and flexor digitorum superficialis during a handwriting task with two groups of subjects using different grasp patterns. Twenty-four university students (thirteen males and eleven females; mean age of 22.04±2.8years) were included in this study. We randomly invited 12 subjects that used the Dynamic Tripod grasp and 12 subjects that used the Static Tripod grasp. The static tripod group showed statistically significant changes in the sEMG activity of trapezium and biceps brachii muscles during handwriting when compared to dynamic tripod group's subjects. No significant differences were found in extensor carpi radialis brevis and flexor digitorum superficialis activities among the two groups. The findings in this study suggest an increased activity of proximal muscles among subjects using a transitional grasp, indicating potential higher energy expenditure and muscular harm with the maintenance of this motor pattern in handwriting tasks, especially during the progression in academic life. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Effects of grasp compatibility on long-term memory for objects.

    Science.gov (United States)

    Canits, Ivonne; Pecher, Diane; Zeelenberg, René

    2018-01-01

    Previous studies have shown action potentiation during conceptual processing of manipulable objects. In four experiments, we investigated whether these motor actions also play a role in long-term memory. Participants categorized objects that afforded either a power grasp or a precision grasp as natural or artifact by grasping cylinders with either a power grasp or a precision grasp. In all experiments, responses were faster when the affordance of the object was compatible with the type of grasp response. However, subsequent free recall and recognition memory tasks revealed no better memory for object pictures and object names for which the grasp affordance was compatible with the grasp response. The present results therefore do not support the hypothesis that motor actions play a role in long-term memory. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Bimanual reach to grasp movements after cervical spinal cord injury.

    Directory of Open Access Journals (Sweden)

    Laura Britten

    Full Text Available Injury to the cervical spinal cord results in bilateral deficits in arm/hand function reducing functional independence and quality of life. To date little research has been undertaken to investigate control strategies of arm/hand movements following cervical spinal cord injury (cSCI. This study aimed to investigate unimanual and bimanual coordination in patients with acute cSCI using 3D kinematic analysis as they performed naturalistic reach to grasp actions with one hand, or with both hands together (symmetrical task, and compare this to the movement patterns of uninjured younger and older adults. Eighteen adults with a cSCI (mean 61.61 years with lesions at C4-C8, with an American Spinal Injury Association (ASIA grade B to D and 16 uninjured younger adults (mean 23.68 years and sixteen uninjured older adults (mean 70.92 years were recruited. Participants with a cSCI produced reach-to-grasp actions which took longer, were slower, and had longer deceleration phases than uninjured participants. These differences were exacerbated during bimanual reach-to-grasp tasks. Maximal grasp aperture was no different between groups, but reached earlier by people with cSCI. Participants with a cSCI were less synchronous than younger and older adults but all groups used the deceleration phase for error correction to end the movement in a synchronous fashion. Overall, this study suggests that after cSCI a level of bimanual coordination is retained. While there seems to be a greater reliance on feedback to produce both the reach to grasp, we observed minimal disruption of the more impaired limb on the less impaired limb. This suggests that bimanual movements should be integrated into therapy.

  7. Sequential phosphorylation of GRASP65 during mitotic Golgi disassembly

    Directory of Open Access Journals (Sweden)

    Danming Tang

    2012-09-01

    GRASP65 phosphorylation during mitosis and dephosphorylation after mitosis are required for Golgi disassembly and reassembly during the cell cycle. At least eight phosphorylation sites on GRASP65 have been identified, but whether they are modified in a coordinated fashion during mitosis is so far unknown. In this study, we raised phospho-specific antibodies that recognize phosphorylated T220/T224, S277 and S376 residues of GRASP65, respectively. Biochemical analysis showed that cdc2 phosphorylates all three sites, while plk1 enhances the phosphorylation. Microscopic studies using these antibodies for double and triple labeling demonstrate sequential phosphorylation and dephosphorylation during the cell cycle. S277 and S376 are phosphorylated from late G2 phase through metaphase until telophase when the new Golgi is reassembled. T220/224 is not modified until prophase, but is highly modified from prometaphase to anaphase. In metaphase, phospho-T220/224 signal localizes on both Golgi haze and mitotic Golgi clusters that represent dispersed Golgi vesicles and Golgi remnants, respectively, while phospho-S277 and S376 labeling is more concentrated on mitotic Golgi clusters. Expression of a phosphorylation-resistant GRASP65 mutant T220A/T224A inhibited mitotic Golgi fragmentation to a much larger extent than the expression of the S277A and S376A mutants. In cytokinesis, T220/224 dephosphorylation occurs prior to that of S277, but after S376. This study provides evidence that GRASP65 is sequentially phosphorylated and dephosphorylated during mitosis at different sites to orchestrate Golgi disassembly and reassembly during cell division, with phosphorylation of the T220/224 site being most critical in the process.

  8. G3DB: A database of successful and failed grasps with RGB-D images, point clouds, mesh models and gripper parameters

    CSIR Research Space (South Africa)

    Kleinhans, A

    2015-05-01

    Full Text Available likely values for them, and adapt to actual object properties during the grasp. Another key piece of information that is missing is the object’s 3D shape. Humans and mobile robots perceive the world from a single viewpoint, making the back and often...

  9. ESTIMATION OF GRASPING TORQUE USING ROBUST REACTION TORQUE OBSERVER FOR ROBOTIC FORCEPS

    OpenAIRE

    塚本, 祐介

    2015-01-01

    Abstract— In this paper, the estimation of the grasping torque of robotic forceps without the use of a force/torque sensor is discussed. To estimate the grasping torque when the robotic forceps driven by a rotary motor with a reduction gear grasps an object, a novel robust reaction torque observer is proposed. In the case where a conventional reaction force/torque observer is applied, the estimated torque includes not only the grasping torque, namely the reaction torque, but also t...

  10. Establishing a library of resources to help people understand key concepts in assessing treatment claims—The “Critical thinking and Appraisal Resource Library” (CARL)

    Science.gov (United States)

    Chalmers, Iain; Atkinson, Patricia; Badenoch, Douglas; Oxman, Andrew D.; Austvoll-Dahlgren, Astrid; Nordheim, Lena; Krause, L. Kendall; Schwartz, Lisa M.; Woloshin, Steven; Burls, Amanda; Mosconi, Paola; Hoffmann, Tammy; Cusack, Leila; Albarqouni, Loai; Glasziou, Paul

    2017-01-01

    Background People are frequently confronted with untrustworthy claims about the effects of treatments. Uncritical acceptance of these claims can lead to poor, and sometimes dangerous, treatment decisions, and wasted time and money. Resources to help people learn to think critically about treatment claims are scarce, and they are widely scattered. Furthermore, very few learning-resources have been assessed to see if they improve knowledge and behavior. Objectives Our objectives were to develop the Critical thinking and Appraisal Resource Library (CARL). This library was to be in the form of a database containing learning resources for those who are responsible for encouraging critical thinking about treatment claims, and was to be made available online. We wished to include resources for groups we identified as ‘intermediaries’ of knowledge, i.e. teachers of schoolchildren, undergraduates and graduates, for example those teaching evidence-based medicine, or those communicating treatment claims to the public. In selecting resources, we wished to draw particular attention to those resources that had been formally evaluated, for example, by the creators of the resource or independent research groups. Methods CARL was populated with learning-resources identified from a variety of sources—two previously developed but unmaintained inventories; systematic reviews of learning-interventions; online and database searches; and recommendations by members of the project group and its advisors. The learning-resources in CARL were organised by ‘Key Concepts’ needed to judge the trustworthiness of treatment claims, and were made available online by the James Lind Initiative in Testing Treatments interactive (TTi) English (www.testingtreatments.org/category/learning-resources).TTi English also incorporated the database of Key Concepts and the Claim Evaluation Tools developed through the Informed Healthcare Choices (IHC) project (informedhealthchoices.org). Results We have

  11. Integration of Advanced Concepts and Vehicles Into the Next Generation Air Transportation System. Volume 1; Introduction, Key Messages, and Vehicle Attributes

    Science.gov (United States)

    Zellweger, Andres; Resnick, Herbert; Stevens, Edward; Arkind, Kenneth; Cotton William B.

    2010-01-01

    Raytheon, in partnership with NASA, is leading the way in ensuring that the future air transportation continues to be a key driver of economic growth and stability and that this system provides an environmentally friendly, safe, and effective means of moving people and goods. A Raytheon-led team of industry and academic experts, under NASA contract NNA08BA47C, looked at the potential issues and impact of introducing four new classes of advanced aircraft into the next generation air transportation system -- known as NextGen. The study will help determine where NASA should further invest in research to support the safe introduction of these new air vehicles. Small uncrewed or unmanned aerial systems (SUAS), super heavy transports (SHT) including hybrid wing body versions (HWB), very light jets (VLJ), and supersonic business jets (SSBJ) are the four classes of aircraft that we studied. Understanding each vehicle's business purpose and strategy is critical to assessing the feasibility of new aircraft operations and their impact on NextGen's architecture. The Raytheon team used scenarios created by aviation experts that depict vehicles in year 2025 operations along with scripts or use cases to understand the issues presented by these new types of vehicles. The information was then mapped into the Joint Planning and Development Office's (JPDO s) Enterprise Architecture to show how the vehicles will fit into NextGen's Concept of Operations. The team also identified significant changes to the JPDO's Integrated Work Plan (IWP) to optimize the NextGen vision for these vehicles. Using a proven enterprise architecture approach and the JPDO s Joint Planning Environment (JPE) web site helped make the leap from architecture to planning efficient, manageable and achievable. Very Light Jets flying into busy hub airports -- Supersonic Business Jets needing to climb and descend rapidly to achieve the necessary altitude Super-heavy cargo planes requiring the shortest common flight

  12. Posture of the arm when grasping spheres to place them elsewhere

    NARCIS (Netherlands)

    Schot, W.D.; Brenner, E.; Smeets, J.B.J.

    2010-01-01

    Despite the infinitely many ways to grasp a spherical object, regularities have been observed in the posture of the arm and the grasp orientation. In the present study, we set out to determine the factors that predict the grasp orientation and the final joint angles of reach-tograsp movements.

  13. Detection, Location and Grasping Objects Using a Stereo Sensor on UAV in Outdoor Environments

    Directory of Open Access Journals (Sweden)

    Pablo Ramon Soria

    2017-01-01

    Full Text Available The article presents a vision system for the autonomous grasping of objects with Unmanned Aerial Vehicles (UAVs in real time. Giving UAVs the capability to manipulate objects vastly extends their applications, as they are capable of accessing places that are difficult to reach or even unreachable for human beings. This work is focused on the grasping of known objects based on feature models. The system runs in an on-board computer on a UAV equipped with a stereo camera and a robotic arm. The algorithm learns a feature-based model in an offline stage, then it is used online for detection of the targeted object and estimation of its position. This feature-based model was proved to be robust to both occlusions and the presence of outliers. The use of stereo cameras improves the learning stage, providing 3D information and helping to filter features in the online stage. An experimental system was derived using a rotary-wing UAV and a small manipulator for final proof of concept. The robotic arm is designed with three degrees of freedom and is lightweight due to payload limitations of the UAV. The system has been validated with different objects, both indoors and outdoors.

  14. Grounded Object and Grasp Representations in a Cognitive Architecture

    DEFF Research Database (Denmark)

    Kraft, Dirk

    developed. This work presents a system that is able to learn autonomously about objects and applicable grasps in an unknown environment through exploratory manipulation and to then use this grounded knowledge in a planning setup to address complex tasks. A set of different subsystems is needed to achieve....... The topics are ordered so that we proceed from the more general integration works towards the works describing the individual components. The first chapter gives an overview over the system that is able to learn a grounded visual object representation and a grounded grasp representation. In the following...... part, we describe how this grounding procedures can be embedded in a three cognitive level architecture. Our initial work to use a tactile sensor to enrichen the object representations as well as allow for more complex actions is presented here as well. Since our system is concerned with learning about...

  15. An Aircraft Service Staff Rostering using a Hybrid GRASP Algorithm

    Directory of Open Access Journals (Sweden)

    W.H. Ip

    2009-10-01

    Full Text Available The aircraft ground service company is responsible for carrying out the regular tasks to aircraft maintenace between their arrival at and departure from the airport. This paper presents the application of a hybrid approach based upon greedy randomized adaptive search procedure (GRASP for rostering technical staff such that they are assigned predefined shift patterns. The rostering of staff is posed as an optimization problem with an aim of minimizing the violations of hard and soft constraints. The proposed algorithm iteratively constructs a set of solutions by GRASP. Furthermore, with multi-agent techniques, we efficiently identify an optimal roster with minimal constraint violations and fair to employees. Experimental results are included to demonstrate the effectiveness of the proposed algorithm.

  16. Modelling the shape hierarchy for visually guided grasping

    Directory of Open Access Journals (Sweden)

    Omid eRezai

    2014-10-01

    Full Text Available The monkey anterior intraparietal area (AIP encodes visual information about three-dimensional object shape that is used to shape the hand for grasping. We modelled shape tuning in visual AIP neurons and its relationship with curvature and gradient information from the caudal intraparietal area (CIP. The main goal was to gain insight into the kinds of shape parameterizations that can account for AIP tuning and that are consistent with both the inputs to AIP and the role of AIP in grasping. We first experimented with superquadric shape parameters. We considered superquadrics because they occupy a role in robotics that is similar to AIP, in that superquadric fits are derived from visual input and used for grasp planning. We also experimented with an alternative shape parameterization that was based on an Isomap dimension reduction of spatial derivatives of depth (i.e. distance from the observer to the object surface. We considered an Isomap-based model because its parameters lacked discontinuities between similar shapes. When we matched the dimension of the Isomap to the number of superquadric parameters, the superquadric model fit the AIP data somewhat more closely. However, higher-dimensional Isomaps provided excellent fits. Also, we found that the Isomap parameters could be approximated much more accurately than superquadric parameters by feedforward neural networks with CIP-like inputs. We conclude that Isomaps, or perhaps alternative dimension reductions of visual inputs to AIP, provide a promising model of AIP electrophysiology data. However (in contrast with superquadrics further work is needed to test whether such shape parameterizations actually provide an effective basis for grasp control.

  17. The Synthesis of Force Closure Grasps in the Plane.

    Science.gov (United States)

    1985-09-01

    TASK U Artificial Inteligence Laboratory AREA A WORK UN IT "NMUIERS ~( 545 Technology Square Cambridge, MA 02139 SI. CONTROLLING OFICE NAME ANO... ARTIFICIAL INThLLIX’ ENCE LABORATORY A. 1. Memo 861 September, 1985 The Synthesis of Force-Closure Grasps In the Plane DTIC ’VeL% ,#ECTE 1 VnDcNguyenU Abstract... Artificial In- telligenmcc Liabomatory of thle Massachuset Is hInsttute of Teclhnolog3 . Support for the Lahoratot * s Artificial Intelligence research is

  18. An Aircraft Service Staff Rostering using a Hybrid GRASP Algorithm

    OpenAIRE

    Cho, Vincent; Wu, Gene Pak Kit; Ip, W.H.

    2009-01-01

    The aircraft ground service company is responsible for carrying out the regular tasks to aircraft maintenace between their arrival at and departure from the airport. This paper presents the application of a hybrid approach based upon greedy randomized adaptive search procedure (GRASP) for rostering technical staff such that they are assigned predefined shift patterns. The rostering of staff is posed as an optimization problem with an aim of minimizing the violations of hard and soft constrain...

  19. Modeling task-specific neuronal ensembles improves decoding of grasp

    Science.gov (United States)

    Smith, Ryan J.; Soares, Alcimar B.; Rouse, Adam G.; Schieber, Marc H.; Thakor, Nitish V.

    2018-06-01

    Objective. Dexterous movement involves the activation and coordination of networks of neuronal populations across multiple cortical regions. Attempts to model firing of individual neurons commonly treat the firing rate as directly modulating with motor behavior. However, motor behavior may additionally be associated with modulations in the activity and functional connectivity of neurons in a broader ensemble. Accounting for variations in neural ensemble connectivity may provide additional information about the behavior being performed. Approach. In this study, we examined neural ensemble activity in primary motor cortex (M1) and premotor cortex (PM) of two male rhesus monkeys during performance of a center-out reach, grasp and manipulate task. We constructed point process encoding models of neuronal firing that incorporated task-specific variations in the baseline firing rate as well as variations in functional connectivity with the neural ensemble. Models were evaluated both in terms of their encoding capabilities and their ability to properly classify the grasp being performed. Main results. Task-specific ensemble models correctly predicted the performed grasp with over 95% accuracy and were shown to outperform models of neuronal activity that assume only a variable baseline firing rate. Task-specific ensemble models exhibited superior decoding performance in 82% of units in both monkeys (p  <  0.01). Inclusion of ensemble activity also broadly improved the ability of models to describe observed spiking. Encoding performance of task-specific ensemble models, measured by spike timing predictability, improved upon baseline models in 62% of units. Significance. These results suggest that additional discriminative information about motor behavior found in the variations in functional connectivity of neuronal ensembles located in motor-related cortical regions is relevant to decode complex tasks such as grasping objects, and may serve the basis for more

  20. Linear and nonlinear subspace analysis of hand movements during grasping.

    Science.gov (United States)

    Cui, Phil Hengjun; Visell, Yon

    2014-01-01

    This study investigated nonlinear patterns of coordination, or synergies, underlying whole-hand grasping kinematics. Prior research has shed considerable light on roles played by such coordinated degrees-of-freedom (DOF), illuminating how motor control is facilitated by structural and functional specializations in the brain, peripheral nervous system, and musculoskeletal system. However, existing analyses suppose that the patterns of coordination can be captured by means of linear analyses, as linear combinations of nominally independent DOF. In contrast, hand kinematics is itself highly nonlinear in nature. To address this discrepancy, we sought to to determine whether nonlinear synergies might serve to more accurately and efficiently explain human grasping kinematics than is possible with linear analyses. We analyzed motion capture data acquired from the hands of individuals as they grasped an array of common objects, using four of the most widely used linear and nonlinear dimensionality reduction algorithms. We compared the results using a recently developed algorithm-agnostic quality measure, which enabled us to assess the quality of the dimensional reductions that resulted by assessing the extent to which local neighborhood information in the data was preserved. Although qualitative inspection of this data suggested that nonlinear correlations between kinematic variables were present, we found that linear modeling, in the form of Principle Components Analysis, could perform better than any of the nonlinear techniques we applied.

  1. Are we real when we fake? Attunement to object weight in natural and pantomimed grasping movements

    Directory of Open Access Journals (Sweden)

    Caterina Ansuini

    2016-09-01

    Full Text Available Behavioural and neuropsychological studies suggest that real actions and pantomimed actions tap, at least in part, different neural systems. Inspired by studies showing weight-attunement in real grasps, here we asked whether (and to what extent kinematics of pantomimed reach-to-grasp movement can reveal the weight of the pretended target. To address this question, we instructed participants (n =15 either to grasp or pretend to grasp towards two differently weighted objects, i.e., a light object and heavy object. Using linear discriminant analysis, we then proceeded to classify the weight of the target – either real or pretended – on the basis of the recorded movement patterns. Classification analysis revealed that pantomimed reach-to-grasp movements retained information about object weight, although to a lesser extent than real grasp movements. These results are discussed in relation to the mechanisms underlying the control of real and pantomimed grasping movements.

  2. Grasp frequency and usage in daily household and machine shop tasks.

    Science.gov (United States)

    Bullock, Ian M; Zheng, Joshua Z; De La Rosa, Sara; Guertler, Charlotte; Dollar, Aaron M

    2013-01-01

    In this paper, we present results from a study of prehensile human hand use during the daily work activities of four subjects: two housekeepers and two machinists. Subjects wore a head-mounted camera that recorded their hand usage during their daily work activities in their typical place of work. For each subject, 7.45 hours of video was analyzed, recording the type of grasp being used and its duration. From this data, we extracted overall grasp frequency, duration distributions for each grasp, and common transitions between grasps. The results show that for 80 percent of the study duration the housekeepers used just five grasps and the machinists used 10. The grasping patterns for the different subjects were compared, and the overall top 10 grasps are discussed in detail. The results of this study not only lend insight into how people use their hands during daily tasks, but can also inform the design of effective robotic and prosthetic hands.

  3. Writing forces associated with four pencil grasp patterns in grade 4 children.

    Science.gov (United States)

    Schwellnus, Heidi; Carnahan, Heather; Kushki, Azadeh; Polatajko, Helene; Missiuna, Cheryl; Chau, Tom

    2013-01-01

    OBJECTIVE. We investigated differences in handwriting kinetics, speed, and legibility among four pencil grasps after a 10-min copy task. METHOD. Seventy-four Grade 4 students completed a handwriting assessment before and after a copy task. Grip and axial forces were measured with an instrumented stylus and force-sensitive tablet. We used multiple linear regression to analyze the relationship between grasp pattern and grip and axial forces. RESULTS. We found no kinetic differences among grasps, whether considered individually or grouped by the number of fingers on the barrel. However, when grasps were grouped according to the thumb position, the adducted grasps exhibited higher mean grip and axial forces. CONCLUSION. Grip forces were generally similar across the different grasps. Kinetic differences resulting from thumb position seemed to have no bearing on speed and legibility. Interventions for handwriting difficulties should focus more on speed and letter formation than on grasp pattern. Copyright © 2013 by the American Occupational Therapy Association, Inc.

  4. A fingertip force prediction model for grasp patterns characterised from the chaotic behaviour of EEG.

    Science.gov (United States)

    Roy, Rinku; Sikdar, Debdeep; Mahadevappa, Manjunatha; Kumar, C S

    2018-05-19

    A stable grasp is attained through appropriate hand preshaping and precise fingertip forces. Here, we have proposed a method to decode grasp patterns from motor imagery and subsequent fingertip force estimation model with a slippage avoidance strategy. We have developed a feature-based classification of electroencephalography (EEG) associated with imagination of the grasping postures. Chaotic behaviour of EEG for different grasping patterns has been utilised to capture the dynamics of associated motor activities. We have computed correlation dimension (CD) as the feature and classified with "one against one" multiclass support vector machine (SVM) to discriminate between different grasping patterns. The result of the analysis showed varying classification accuracies at different subband levels. Broad categories of grasping patterns, namely, power grasp and precision grasp, were classified at a 96.0% accuracy rate in the alpha subband. Furthermore, power grasp subtypes were classified with an accuracy of 97.2% in the upper beta subband, whereas precision grasp subtypes showed relatively lower 75.0% accuracy in the alpha subband. Following assessment of fingertip force distributions while grasping, a nonlinear autoregressive (NAR) model with proper prediction of fingertip forces was proposed for each grasp pattern. A slippage detection strategy has been incorporated with automatic recalibration of the regripping force. Intention of each grasp pattern associated with corresponding fingertip force model was virtualised in this work. This integrated system can be utilised as the control strategy for prosthetic hand in the future. The model to virtualise motor imagery based fingertip force prediction with inherent slippage correction for different grasp types ᅟ.

  5. Decoding Grasping Movements from the Parieto-Frontal Reaching Circuit in the Nonhuman Primate.

    Science.gov (United States)

    Nelissen, Koen; Fiave, Prosper Agbesi; Vanduffel, Wim

    2018-04-01

    Prehension movements typically include a reaching phase, guiding the hand toward the object, and a grip phase, shaping the hand around it. The dominant view posits that these components rely upon largely independent parieto-frontal circuits: a dorso-medial circuit involved in reaching and a dorso-lateral circuit involved in grasping. However, mounting evidence suggests a more complex arrangement, with dorso-medial areas contributing to both reaching and grasping. To investigate the role of the dorso-medial reaching circuit in grasping, we trained monkeys to reach-and-grasp different objects in the dark and determined if hand configurations could be decoded from functional magnetic resonance imaging (MRI) responses obtained from the reaching and grasping circuits. Indicative of their established role in grasping, object-specific grasp decoding was found in anterior intraparietal (AIP) area, inferior parietal lobule area PFG and ventral premotor region F5 of the lateral grasping circuit, and primary motor cortex. Importantly, the medial reaching circuit also conveyed robust grasp-specific information, as evidenced by significant decoding in parietal reach regions (particular V6A) and dorsal premotor region F2. These data support the proposed role of dorso-medial "reach" regions in controlling aspects of grasping and demonstrate the value of complementing univariate with more sensitive multivariate analyses of functional MRI (fMRI) data in uncovering information coding in the brain.

  6. Force coordination in static manipulation tasks performed using standard and non-standard grasping techniques.

    Science.gov (United States)

    de Freitas, Paulo B; Jaric, Slobodan

    2009-04-01

    We evaluated coordination of the hand grip force (GF; normal component of the force acting at the hand-object contact area) and load force (LF; the tangential component) in a variety of grasping techniques and two LF directions. Thirteen participants exerted a continuous sinusoidal LF pattern against externally fixed handles applying both standard (i.e., using either the tips of the digits or the palms; the precision and palm grasps, respectively) and non-standard grasping techniques (using wrists and the dorsal finger areas; the wrist and fist grasp). We hypothesized (1) that the non-standard grasping techniques would provide deteriorated indices of force coordination when compared with the standard ones, and (2) that the nervous system would be able to adjust GF to the differences in friction coefficients of various skin areas used for grasping. However, most of the indices of force coordination remained similar across the tested grasping techniques, while the GF adjustments for the differences in friction coefficients (highest in the palm and the lowest in the fist and wrist grasp) provided inconclusive results. As hypothesized, GF relative to the skin friction was lowest in the precision grasp, but highest in the palm grasp. Therefore, we conclude that (1) the elaborate coordination of GF and LF consistently seen across the standard grasping techniques could be generalized to the non-standard ones, while (2) the ability to adjust GF using the same grasping technique to the differences in friction of various objects cannot be fully generalized to the GF adjustment when different grasps (i.e., hand segments) are used to manipulate the same object. Due to the importance of the studied phenomena for understanding both the functional and neural control aspects of manipulation, future studies should extend the current research to the transient and dynamic tasks, as well as to the general role of friction in our mechanical interactions with the environment.

  7. Visual Field Preferences of Object Analysis for Grasping with One Hand

    Directory of Open Access Journals (Sweden)

    Ada eLe

    2014-10-01

    Full Text Available When we grasp an object using one hand, the opposite hemisphere predominantly guides the motor control of grasp movements (Davare et al. 2007; Rice et al. 2007. However, it is unclear whether visual object analysis for grasp control relies more on inputs (a from the contralateral than the ipsilateral visual field, (b from one dominant visual field regardless of the grasping hand, or (c from both visual fields equally. For bimanual grasping of a single object we have recently demonstrated a visual field preference for the left visual field (Le and Niemeier 2013a, 2013b, consistent with a general right-hemisphere dominance for sensorimotor control of bimanual grasps (Le et al., 2013. But visual field differences have never been tested for unimanual grasping. Therefore, here we asked right-handed participants to fixate to the left or right of an object and then grasp the object either with their right or left hand using a precision grip. We found that participants grasping with their right hand performed better with objects in the right visual field: maximum grip apertures (MGAs were more closely matched to the object width and were smaller than for objects in the left visual field. In contrast, when people grasped with their left hand, preferences switched to the left visual field. What is more, MGA scaling showed greater visual field differences compared to right-hand grasping. Our data suggest that, visual object analysis for unimanual grasping shows a preference for visual information from the ipsilateral visual field, and that the left hemisphere is better equipped to control grasps in both visual fields.

  8. Gaze strategies during visually-guided versus memory-guided grasping.

    Science.gov (United States)

    Prime, Steven L; Marotta, Jonathan J

    2013-03-01

    Vision plays a crucial role in guiding motor actions. But sometimes we cannot use vision and must rely on our memory to guide action-e.g. remembering where we placed our eyeglasses on the bedside table when reaching for them with the lights off. Recent studies show subjects look towards the index finger grasp position during visually-guided precision grasping. But, where do people look during memory-guided grasping? Here, we explored the gaze behaviour of subjects as they grasped a centrally placed symmetrical block under open- and closed-loop conditions. In Experiment 1, subjects performed grasps in either a visually-guided task or memory-guided task. The results show that during visually-guided grasping, gaze was first directed towards the index finger's grasp point on the block, suggesting gaze targets future grasp points during the planning of the grasp. Gaze during memory-guided grasping was aimed closer to the blocks' centre of mass from block presentation to the completion of the grasp. In Experiment 2, subjects performed an 'immediate grasping' task in which vision of the block was removed immediately at the onset of the reach. Similar to the visually-guided results from Experiment 1, gaze was primarily directed towards the index finger location. These results support the 2-stream theory of vision in that motor planning with visual feedback at the onset of the movement is driven primarily by real-time visuomotor computations of the dorsal stream, whereas grasping remembered objects without visual feedback is driven primarily by the perceptual memory representations mediated by the ventral stream.

  9. Real-time vision, tactile cues, and visual form agnosia in pantomimed grasping: removing haptic feedback induces a switch from natural to pantomime-like grasps

    Directory of Open Access Journals (Sweden)

    Robert Leslie Whitwell

    2015-05-01

    Full Text Available Investigators study the kinematics of grasping movements (prehension under a variety of conditions to probe visuomotor function in normal and brain-damaged individuals. When patient DF, who suffers from visual form agnosia, performs natural grasps, her in-flight hand aperture is scaled to the widths of targets ('grip scaling' that she cannot discriminate amongst. In contrast, when DF's pantomime grasps are based on a memory of a previewed object, her grip scaling is very poor. Her failure on this task has been interpreted as additional support for the dissociation between the use of object vision for action and object vision for perception. Curiously, however, when DF directs her pantomimed grasps towards a displaced imagined copy of a visible object where her fingers make contact with the surface of the table, her grip scaling does not appear to be particularly poor. In the first of two experiments, we revisit this previous work and show that her grip scaling in this real-time pantomime grasping task does not differ from controls, suggesting that terminal tactile feedback from a proxy of the target can maintain DF's grip scaling. In a second experiment with healthy participants, we tested a recent variant of a grasping task in which no tactile feedback is available (i.e. no haptic feedback by comparing the kinematics of target-directed grasps with and without haptic feedback to those of real-time pantomime grasps without haptic feedback. Compared to natural grasps, removing haptic feedback increased RT, slowed the velocity of the reach, reduced grip aperture, sharpened the slopes relating grip aperture to target width, and reduced the final grip aperture. All of these effects were also observed in the pantomime grasping task. Taken together, these results provide compelling support for the view that removing haptic feedback induces a switch from real-time visual control to one that depends more on visual perception and cognitive supervision.

  10. Identifying relevant feature-action associations for grasping unmodelled objects

    DEFF Research Database (Denmark)

    Thomsen, Mikkel Tang; Kraft, Dirk; Krüger, Norbert

    2015-01-01

    content. The method is provided with a large and structured set of visual features, motivated by the visual hierarchy in primates and finds relevant feature action associations automatically. We apply our method in a simulated environment on three different object sets for the case of grasp affordance...... learning. For box objects, we achieve a 0.90 success probability, 0.80 for round objects and up to 0.75 for open objects, when presented with novel objects. In this work, we in particular demonstrate the effect of choosing appropriate feature representations. We demonstrate a significant performance...

  11. Aircraft Route Recovery Based on An Improved GRASP Method

    Directory of Open Access Journals (Sweden)

    Yang He

    2017-01-01

    Full Text Available Aircrafts maintenance, temporary airport closures are common factors that disrupt normal flight schedule. The aircraft route recovery aims to recover original schedules by some strategies, including flights swaps, and cancellations, which is a NP-hard problem. This paper proposes an improved heuristic procedure based on Greedy Random Adaptive Search Procedure (GRASP to solve this problem. The effectiveness and high global optimization capability of the heuristic is illustrated through experiments based on large-scale problems. Compared to the original one, it is shown that the improved procedure can find feasible flight recovered schedules with lower cost in a short time.

  12. Electrotactile EMG feedback improves the control of prosthesis grasping force

    Science.gov (United States)

    Schweisfurth, Meike A.; Markovic, Marko; Dosen, Strahinja; Teich, Florian; Graimann, Bernhard; Farina, Dario

    2016-10-01

    Objective. A drawback of active prostheses is that they detach the subject from the produced forces, thereby preventing direct mechanical feedback. This can be compensated by providing somatosensory feedback to the user through mechanical or electrical stimulation, which in turn may improve the utility, sense of embodiment, and thereby increase the acceptance rate. Approach. In this study, we compared a novel approach to closing the loop, namely EMG feedback (emgFB), to classic force feedback (forceFB), using electrotactile interface in a realistic task setup. Eleven intact-bodied subjects and one transradial amputee performed a routine grasping task while receiving emgFB or forceFB. The two feedback types were delivered through the same electrotactile interface, using a mixed spatial/frequency coding to transmit 8 discrete levels of the feedback variable. In emgFB, the stimulation transmitted the amplitude of the processed myoelectric signal generated by the subject (prosthesis input), and in forceFB the generated grasping force (prosthesis output). The task comprised 150 trials of routine grasping at six forces, randomly presented in blocks of five trials (same force). Interquartile range and changes in the absolute error (AE) distribution (magnitude and dispersion) with respect to the target level were used to assess precision and overall performance, respectively. Main results. Relative to forceFB, emgFB significantly improved the precision of myoelectric commands (min/max of the significant levels) for 23%/36% as well as the precision of force control for 12%/32%, in intact-bodied subjects. Also, the magnitude and dispersion of the AE distribution were reduced. The results were similar in the amputee, showing considerable improvements. Significance. Using emgFB, the subjects therefore decreased the uncertainty of the forward pathway. Since there is a correspondence between the EMG and force, where the former anticipates the latter, the emgFB allowed for

  13. Distinct neural patterns enable grasp types decoding in monkey dorsal premotor cortex

    Science.gov (United States)

    Hao, Yaoyao; Zhang, Qiaosheng; Controzzi, Marco; Cipriani, Christian; Li, Yue; Li, Juncheng; Zhang, Shaomin; Wang, Yiwen; Chen, Weidong; Chiara Carrozza, Maria; Zheng, Xiaoxiang

    2014-12-01

    Objective. Recent studies have shown that dorsal premotor cortex (PMd), a cortical area in the dorsomedial grasp pathway, is involved in grasp movements. However, the neural ensemble firing property of PMd during grasp movements and the extent to which it can be used for grasp decoding are still unclear. Approach. To address these issues, we used multielectrode arrays to record both spike and local field potential (LFP) signals in PMd in macaque monkeys performing reaching and grasping of one of four differently shaped objects. Main results. Single and population neuronal activity showed distinct patterns during execution of different grip types. Cluster analysis of neural ensemble signals indicated that the grasp related patterns emerged soon (200-300 ms) after the go cue signal, and faded away during the hold period. The timing and duration of the patterns varied depending on the behaviors of individual monkey. Application of support vector machine model to stable activity patterns revealed classification accuracies of 94% and 89% for each of the two monkeys, indicating a robust, decodable grasp pattern encoded in the PMd. Grasp decoding using LFPs, especially the high-frequency bands, also produced high decoding accuracies. Significance. This study is the first to specify the neuronal population encoding of grasp during the time course of grasp. We demonstrate high grasp decoding performance in PMd. These findings, combined with previous evidence for reach related modulation studies, suggest that PMd may play an important role in generation and maintenance of grasp action and may be a suitable locus for brain-machine interface applications.

  14. Independent in the heard: Inclusion and exclusion as social processes. Proceedings from the 9th GRASP conference, Linköping University, May 2014

    OpenAIRE

    2014-01-01

    GRASP (Group and Social Psychology) is an interdisciplinary conference, which aims to provide a community around social psychological issues for researchers, practitioners, and graduate students from the Nordic countries within the fields of psychology, sociology, education, behavioural sciences and social work to share, exchange, learn, and develop preliminary results, new concepts, ideas, principles, and methodologies, as well as bridging the gaps between paradigms, encouraging interdiscipl...

  15. Haptically guided grasping. FMRI shows right-hemisphere parietal stimulus encoding, and bilateral dorso-ventral parietal gradients of object- and action-related processing during grasp execution

    Directory of Open Access Journals (Sweden)

    Mattia eMarangon

    2016-01-01

    Full Text Available The neural bases of haptically-guided grasp planning and execution are largely unknown, especially for stimuli having no visual representations. Therefore, we used functional magnetic resonance imaging (fMRI to monitor brain activity during haptic exploration of novel 3D complex objects, subsequent grasp planning, and the execution of the pre-planned grasps. Haptic object exploration, involving extraction of shape, orientation and length of the to-be-grasped targets, was associated with the fronto-parietal, temporo-occipital, and insular cortex activity. Yet, only the anterior divisions of the posterior parietal cortex (PPC of the right hemisphere were significantly more engaged in exploration of complex objects (vs. simple control disks. None of these regions were re-recruited during the planning phase. Even more surprisingly, the left-hemisphere intraparietal, temporal, and occipital areas that were significantly invoked for grasp planning did not show sensitivity to object features. Finally, grasp execution, involving the re-recruitment of the critical right-hemisphere PPC clusters, was also significantly associated with two kinds of bilateral parieto-frontal processes. The first represents transformations of grasp-relevant target features and is linked to the dorso-dorsal (lateral and medial parieto-frontal networks. The second monitors grasp kinematics and belongs to the ventro-dorsal networks. Indeed, signal modulations associated with these distinct functions follow dorso-ventral gradients, with left aIPS showing significant sensitivity to both target features and the characteristics of the required grasp. Thus, our results from the haptic domain are consistent with the notion that the parietal processing for action guidance reflects primarily transformations from object-related to effector-related coding, and these mechanisms are rather independent of sensory input modality.

  16. Mena-GRASP65 interaction couples actin polymerization to Golgi ribbon linking.

    Science.gov (United States)

    Tang, Danming; Zhang, Xiaoyan; Huang, Shijiao; Yuan, Hebao; Li, Jie; Wang, Yanzhuang

    2016-01-01

    In mammalian cells, the Golgi reassembly stacking protein 65 (GRASP65) has been implicated in both Golgi stacking and ribbon linking by forming trans-oligomers through the N-terminal GRASP domain. Because the GRASP domain is globular and relatively small, but the gaps between stacks are large and heterogeneous, it remains puzzling how GRASP65 physically links Golgi stacks into a ribbon. To explore the possibility that other proteins may help GRASP65 in ribbon linking, we used biochemical methods and identified the actin elongation factor Mena as a novel GRASP65-binding protein. Mena is recruited onto the Golgi membranes through interaction with GRASP65. Depleting Mena or disrupting actin polymerization resulted in Golgi fragmentation. In cells, Mena and actin were required for Golgi ribbon formation after nocodazole washout; in vitro, Mena and microfilaments enhanced GRASP65 oligomerization and Golgi membrane fusion. Thus Mena interacts with GRASP65 to promote local actin polymerization, which facilitates Golgi ribbon linking. © 2016 Tang et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  17. Virtual grasping: closed-loop force control using electrotactile feedback.

    Science.gov (United States)

    Jorgovanovic, Nikola; Dosen, Strahinja; Djozic, Damir J; Krajoski, Goran; Farina, Dario

    2014-01-01

    Closing the control loop by providing somatosensory feedback to the user of a prosthesis is a well-known, long standing challenge in the field of prosthetics. Various approaches have been investigated for feedback restoration, ranging from direct neural stimulation to noninvasive sensory substitution methods. Although there are many studies presenting closed-loop systems, only a few of them objectively evaluated the closed-loop performance, mostly using vibrotactile stimulation. Importantly, the conclusions about the utility of the feedback were partly contradictory. The goal of the current study was to systematically investigate the capability of human subjects to control grasping force in closed loop using electrotactile feedback. We have developed a realistic experimental setup for virtual grasping, which operated in real time, included a set of real life objects, as well as a graphical and dynamical model of the prosthesis. We have used the setup to test 10 healthy, able bodied subjects to investigate the role of training, feedback and feedforward control, robustness of the closed loop, and the ability of the human subjects to generalize the control to previously "unseen" objects. Overall, the outcomes of this study are very optimistic with regard to the benefits of feedback and reveal various, practically relevant, aspects of closed-loop control.

  18. Virtual Grasping: Closed-Loop Force Control Using Electrotactile Feedback

    Directory of Open Access Journals (Sweden)

    Nikola Jorgovanovic

    2014-01-01

    Full Text Available Closing the control loop by providing somatosensory feedback to the user of a prosthesis is a well-known, long standing challenge in the field of prosthetics. Various approaches have been investigated for feedback restoration, ranging from direct neural stimulation to noninvasive sensory substitution methods. Although there are many studies presenting closed-loop systems, only a few of them objectively evaluated the closed-loop performance, mostly using vibrotactile stimulation. Importantly, the conclusions about the utility of the feedback were partly contradictory. The goal of the current study was to systematically investigate the capability of human subjects to control grasping force in closed loop using electrotactile feedback. We have developed a realistic experimental setup for virtual grasping, which operated in real time, included a set of real life objects, as well as a graphical and dynamical model of the prosthesis. We have used the setup to test 10 healthy, able bodied subjects to investigate the role of training, feedback and feedforward control, robustness of the closed loop, and the ability of the human subjects to generalize the control to previously “unseen” objects. Overall, the outcomes of this study are very optimistic with regard to the benefits of feedback and reveal various, practically relevant, aspects of closed-loop control.

  19. Human Hand Motion Analysis and Synthesis of Optimal Power Grasps for a Robotic Hand

    Directory of Open Access Journals (Sweden)

    Francesca Cordella

    2014-03-01

    Full Text Available Biologically inspired robotic systems can find important applications in biomedical robotics, since studying and replicating human behaviour can provide new insights into motor recovery, functional substitution and human-robot interaction. The analysis of human hand motion is essential for collecting information about human hand movements useful for generalizing reaching and grasping actions on a robotic system. This paper focuses on the definition and extraction of quantitative indicators for describing optimal hand grasping postures and replicating them on an anthropomorphic robotic hand. A motion analysis has been carried out on six healthy human subjects performing a transverse volar grasp. The extracted indicators point to invariant grasping behaviours between the involved subjects, thus providing some constraints for identifying the optimal grasping configuration. Hence, an optimization algorithm based on the Nelder-Mead simplex method has been developed for determining the optimal grasp configuration of a robotic hand, grounded on the aforementioned constraints. It is characterized by a reduced computational cost. The grasp stability has been tested by introducing a quality index that satisfies the form-closure property. The grasping strategy has been validated by means of simulation tests and experimental trials on an arm-hand robotic system. The obtained results have shown the effectiveness of the extracted indicators to reduce the non-linear optimization problem complexity and lead to the synthesis of a grasping posture able to replicate the human behaviour while ensuring grasp stability. The experimental results have also highlighted the limitations of the adopted robotic platform (mainly due to the mechanical structure to achieve the optimal grasp configuration.

  20. Imagination, Perceptual Engagement and Sound Mediation. Thinking Technologically-Produced Sound Through Simondon's Concept of the Image

    NARCIS (Netherlands)

    Paiuk, G.

    2018-01-01

    Applying French philosopher Gilbert Simondon’s concept of image to the domain of the sonorous, this article aims to tackle how imagination is constitutional in our grasp of sound, and how this grasp is informed by the protocols and affordances of technological tools of sound reproduction and

  1. Revaluation of the concept of the human condition and the common heritage of mankind: Keys to the social benefits of space technology

    Science.gov (United States)

    Cocca, Aldo Armando

    Men may do many things, but they must never forget the human condition in any act or relation with a fellow human being. Space Law has vindicated the supreme value of man as a legal subject par excellence. The dignity of the human being is a value that rates above any scientific or technological advance. A benefit, by definition and derivation, is anything contributing to an improvement in a condition. Social benefits pertain only to human beings, who are their sole beneficiaries. Developing countries are young nations that through their international relations may, and indeed must, realize the benefits of space technology. The principle of the "common heritage of Mankind" was created to satisfy the aspirations of all peoples and to meet the needs of both industrialized and developing countries. Only a groundless fear and lack of vision of the future can induce governments to delay its implementation. We must not forget that the concept was transformed into a principle of international positive law by the unanimous decision of the international community, which enshrined it in the Moon Agreement. The social and individual responsibility of the scientist is becoming even more clearly defined, and scientists play an important role in the conduct of nations. Through education, including education in the humanities and a graduation pledge, the scientist has embarked on the road leading to an active presence in society, facing his responsibility. Inter-generational equity contributes to strengthening the concept of the human condition and the legal principle of the common heritage of mankind.

  2. GRASP/Ada 95: Reverse Engineering Tools for Ada

    Science.gov (United States)

    Cross, James H., II

    1996-01-01

    The GRASP/Ada project (Graphical Representations of Algorithms, Structures, and Processes for Ada) has successfully created and prototyped an algorithmic level graphical representation for Ada software, the Control Structure Diagram (CSD), and a new visualization for a fine-grained complexity metric called the Complexity Profile Graph (CPG). By synchronizing the CSD and the CPG, the CSD view of control structure, nesting, and source code is directly linked to the corresponding visualization of statement level complexity in the CPG. GRASP has been integrated with GNAT, the GNU Ada 95 Translator to provide a comprehensive graphical user interface and development environment for Ada 95. The user may view, edit, print, and compile source code as a CSD with no discernible addition to storage or computational overhead. The primary impetus for creation of the CSD was to improve the comprehension efficiency of Ada software and, as a result, improve reliability and reduce costs. The emphasis has been on the automatic generation of the CSD from Ada 95 source code to support reverse engineering and maintenance. The CSD has the potential to replace traditional prettyprinted Ada source code. The current update has focused on the design and implementation of a new Motif compliant user interface, and a new CSD generator consisting of a tagger and renderer. The Complexity Profile Graph (CPG) is based on a set of functions that describes the context, content, and the scaling for complexity on a statement by statement basis. When combined graphicafly, the result is a composite profile of complexity for the program unit. Ongoing research includes the development and refinement of the associated functions, and the development of the CPG generator prototype. The current Version 5.0 prototype provides the capability for the user to generate CSDs and CPGs from Ada 95 source code in a reverse engineering as well as forward engineering mode with a level of flexibility suitable for

  3. Update of GRASP/Ada reverse engineering tools for Ada

    Science.gov (United States)

    Cross, James H., II

    1993-01-01

    The GRASP/Ada project (Graphical Representations of Algorithms, Structures, and Processes for Ada) successfully created and prototyped a new algorithmic level graphical representation for Ada software, the Control Structure Diagram (CSD). The primary impetus for creation of the CSD was to improve the comprehension efficiency of Ada software and, as a result, improve reliability and reduce costs. The emphasis was on the automatic generation of the CSD from Ada PDL or source code to support reverse engineering and maintenance. The CSD has the potential to replace traditional pretty printed Ada source code. In Phase 1 of the GRASP/Ada project, the CSD graphical constructs were created and applied manually to several small Ada programs. A prototype CSD generator (Version 1) was designed and implemented using FLEX and BISON running under VMS on a VAX 11-780. In Phase 2, the prototype was improved and ported to the Sun 4 platform under UNIX. A user interface was designed and partially implemented using the HP widget toolkit and the X Windows System. In Phase 3, the user interface was extensively reworked using the Athena widget toolkit and X Windows. The prototype was applied successfully to numerous Ada programs ranging in size from several hundred to several thousand lines of source code. Following Phase 3,e two update phases were completed. Update'92 focused on the initial analysis of evaluation data collected from software engineering students at Auburn University and the addition of significant enhancements to the user interface. Update'93 (the current update) focused on the statistical analysis of the data collected in the previous update and preparation of Version 3.4 of the prototype for limited distribution to facilitate further evaluation. The current prototype provides the capability for the user to generate CSD's from Ada PDL or source code in a reverse engineering as well as forward engineering mode with a level of flexibility suitable for practical

  4. Reach-to-grasp movement as a minimization process.

    Science.gov (United States)

    Yang, Fang; Feldman, Anatol G

    2010-02-01

    It is known that hand transport and grasping are functionally different but spatially coordinated components of reach-to-grasp (RTG) movements. As an extension of this notion, we suggested that body segments involved in RTG movements are controlled as a coherent ensemble by a global minimization process associated with the necessity for the hand to reach the motor goal. Different RTG components emerge following this process without pre-programming. Specifically, the minimization process may result from the tendency of neuromuscular elements to diminish the spatial gap between the actual arm-hand configuration and its virtual (referent) configuration specified by the brain. The referent configuration is specified depending on the object shape, localization, and orientation. Since the minimization process is gradual, it can be interrupted and resumed following mechanical perturbations, at any phase during RTG movements, including hand closure. To test this prediction of the minimization hypothesis, we asked subjects to reach and grasp a cube placed within the reach of the arm. Vision was prevented during movement until the hand returned to its initial position. As predicted, by arresting wrist motion at different points of hand transport in randomly selected trials, it was possible to halt changes in hand aperture at any phase, not only during hand opening but also during hand closure. Aperture changes resumed soon after the wrist was released. Another test of the minimization hypothesis was made in RTG movements to an object placed beyond the reach of the arm. It has previously been shown (Rossi et al. in J Physiol 538:659-671, 2002) that in such movements, the trunk motion begins to contribute to hand transport only after a critical phase when the shifts in the referent arm configuration have finished (at about the time when hand velocity is maximal). The minimization rule suggests that when the virtual contribution of the arm to hand transport is completed

  5. Concepts of modern mathematics

    CERN Document Server

    Stewart, Ian

    1995-01-01

    Some years ago, ""new math"" took the country's classrooms by storm. Based on the abstract, general style of mathematical exposition favored by research mathematicians, its goal was to teach students not just to manipulate numbers and formulas, but to grasp the underlying mathematical concepts. The result, at least at first, was a great deal of confusion among teachers, students, and parents. Since then, the negative aspects of ""new math"" have been eliminated and its positive elements assimilated into classroom instruction.In this charming volume, a noted English mathematician uses humor an

  6. Responses of mirror neurons in area F5 to hand and tool grasping observation

    Science.gov (United States)

    Rochat, Magali J.; Caruana, Fausto; Jezzini, Ahmad; Escola, Ludovic; Intskirveli, Irakli; Grammont, Franck; Gallese, Vittorio; Rizzolatti, Giacomo

    2010-01-01

    Mirror neurons are a distinct class of neurons that discharge both during the execution of a motor act and during observation of the same or similar motor act performed by another individual. However, the extent to which mirror neurons coding a motor act with a specific goal (e.g., grasping) might also respond to the observation of a motor act having the same goal, but achieved with artificial effectors, is not yet established. In the present study, we addressed this issue by recording mirror neurons from the ventral premotor cortex (area F5) of two monkeys trained to grasp objects with pliers. Neuron activity was recorded during the observation and execution of grasping performed with the hand, with pliers and during observation of an experimenter spearing food with a stick. The results showed that virtually all neurons responding to the observation of hand grasping also responded to the observation of grasping with pliers and, many of them to the observation of spearing with a stick. However, the intensity and pattern of the response differed among conditions. Hand grasping observation determined the earliest and the strongest discharge, while pliers grasping and spearing observation triggered weaker responses at longer latencies. We conclude that F5 grasping mirror neurons respond to the observation of a family of stimuli leading to the same goal. However, the response pattern depends upon the similarity between the observed motor act and the one executed by the hand, the natural motor template. PMID:20577726

  7. Short-Term Plasticity of the Visuomotor Map during Grasping Movements in Humans

    Science.gov (United States)

    Safstrom, Daniel; Edin, Benoni B.

    2005-01-01

    During visually guided grasping movements, visual information is transformed into motor commands. This transformation is known as the "visuomotor map." To investigate limitations in the short-term plasticity of the visuomotor map in normal humans, we studied the maximum grip aperture (MGA) during the reaching phase while subjects grasped objects…

  8. Development of Reaching and Grasping Skills in Infants with Down Syndrome

    Science.gov (United States)

    de Campos, Ana Carolina; Rocha, Nelci Adriana Cicuto Ferreira; Savelsbergh, Geert J. P.

    2010-01-01

    Reaching and grasping skills have been described to emerge from a dynamic interaction between intrinsic and extrinsic factors. The aims of the study were to investigate the effect of such intrinsic factors as age and Down syndrome on the development of reaching and grasping skills and on overall gross motor skill, and to test the influence of the…

  9. Cortical control of object-specific grasp relies on adjustments of both activity and effective connectivity

    DEFF Research Database (Denmark)

    Tia, Banty; Takemi, Mitsuaki; Kosugi, Akito

    2017-01-01

    The cortical mechanisms of grasping have been extensively studied in macaques and humans. Here, we investigated whether common marmosets could rely on similar mechanisms despite striking differences in manual dexterity. Two common marmosets were trained to grasp-and-pull three objects eliciting d...

  10. Software for relativistic atomic structure theory: The grasp project at oxford

    International Nuclear Information System (INIS)

    Parpia, F.A.; Grant, I.P.

    1991-01-01

    GRASP is an acronym for General-purpose Relativistic Atomic Structure Program. The objective of the GRASP project at Oxford is to produce user-friendly state-of-the-art multiconfiguration Dirac-Fock (MCDF) software packages for rleativistic atomic structure theory

  11. GRASP55 Senses Glucose Deprivation through O-GlcNAcylation to Promote Autophagosome-Lysosome Fusion.

    Science.gov (United States)

    Zhang, Xiaoyan; Wang, Leibin; Lak, Behnam; Li, Jie; Jokitalo, Eija; Wang, Yanzhuang

    2018-04-23

    The Golgi apparatus is the central hub for protein trafficking and glycosylation in the secretory pathway. However, how the Golgi responds to glucose deprivation is so far unknown. Here, we report that GRASP55, the Golgi stacking protein located in medial- and trans-Golgi cisternae, is O-GlcNAcylated by the O-GlcNAc transferase OGT under growth conditions. Glucose deprivation reduces GRASP55 O-GlcNAcylation. De-O-GlcNAcylated GRASP55 forms puncta outside of the Golgi area, which co-localize with autophagosomes and late endosomes/lysosomes. GRASP55 depletion reduces autophagic flux and results in autophagosome accumulation, while expression of an O-GlcNAcylation-deficient mutant of GRASP55 accelerates autophagic flux. Biochemically, GRASP55 interacts with LC3-II on the autophagosomes and LAMP2 on late endosomes/lysosomes and functions as a bridge between LC3-II and LAMP2 for autophagosome and lysosome fusion; this function is negatively regulated by GRASP55 O-GlcNAcylation. Therefore, GRASP55 senses glucose levels through O-GlcNAcylation and acts as a tether to facilitate autophagosome maturation. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. Development of Reaching and Grasping skills in infants with Down syndrome

    NARCIS (Netherlands)

    de Campos, A.C.; Rocha, N.A.C.F.; Savelsbergh, G.J.P.

    2010-01-01

    Reaching and grasping skills have been described to emerge from a dynamic interaction between intrinsic and extrinsic factors. The aims of the study were to investigate the effect of such intrinsic factors as age and Down syndrome on the development of reaching and grasping skills and on overall

  13. A GRASP algorithm for the container stowage slot planning problem

    DEFF Research Database (Denmark)

    Parreno, Francisco; Pacino, Dario; Alvarez-Valdes, Ramon

    2016-01-01

    in clusters along the vessel. For each of those clusters a specific position for each container must be found. Compared to previous studies, we have introduced two new features: the explicit handling of rolled out containers and the inclusion of separations rules for dangerous cargo. We present a novel......This work presents a generalization of the Slot Planning Problem which raises when the liner shipping industry needs to plan the placement of containers within a vessel (stowage planning). State-of-the-art stowage planning relies on a heuristic decomposition where containers are first distributed...... integer programming formulation and a Greedy Randomized Adaptive Search Procedure (GRASP) to solve the problem. The approach is able to find high-quality solution within 1 s. We also provide comparison with the state-of-the-art on an existing and a new set of benchmark instances. (C) 2016 Elsevier Ltd...

  14. Grasp Assist Device with Shared Tendon Actuator Assembly

    Science.gov (United States)

    Ihrke, Chris A. (Inventor); Bergelin, Bryan J. (Inventor); Bridgwater, Lyndon (Inventor)

    2015-01-01

    A grasp assist device includes a glove with first and second tendon-driven fingers, a tendon, and a sleeve with a shared tendon actuator assembly. Tendon ends are connected to the respective first and second fingers. The actuator assembly includes a drive assembly having a drive axis and a tendon hook. The tendon hook, which defines an arcuate surface slot, is linearly translatable along the drive axis via the drive assembly, e.g., a servo motor thereof. The flexible tendon is routed through the surface slot such that the surface slot divides the flexible tendon into two portions each terminating in a respective one of the first and second ends. The drive assembly may include a ball screw and nut. An end cap of the actuator assembly may define two channels through which the respective tendon portions pass. The servo motor may be positioned off-axis with respect to the drive axis.

  15. Grip type and task goal modify reach-to-grasp performance in post-stroke hemiparesis.

    Science.gov (United States)

    Schaefer, Sydney Y; DeJong, Stacey L; Cherry, Kendra M; Lang, Catherine E

    2012-04-01

    This study investigated whether grip type and/or task goal influenced reaching and grasping performance in poststroke hemiparesis. Sixteen adults with poststroke hemiparesis and twelve healthy adults reached to and grasped a cylindrical object using one of two grip types (3-finger or palmar) to achieve one of two task goals (hold or lift). Performance of the stroke group was characteristic of hemiparetic limb movement during reach-to-grasp, with more curved handpaths and slower velocities compared with the control group. These effects were present regardless of grip type or task goal. Other measures of reaching (reach time and reach velocity at object contact) and grasping (peak thumb-index finger aperture during the reach and peak grip force during the grasp) were differentially affected by grip type, task goal, or both, despite the presence of hemiparesis, providing new evidence that changes in motor patterns after stroke may occur to compensate for stroke-related motor impairment.

  16. Virtual Control of Prosthetic Hand Based on Grasping Patterns and Estimated Force from Semg

    Directory of Open Access Journals (Sweden)

    Zhu Gao-Ke

    2016-01-01

    Full Text Available Myoelectric prosthetic hands aim to serve upper limb amputees. The myoelectric control of the hand grasp action is a kind of real-time or online method. Thus it is of great necessity to carry on a study of online prosthetic hand electrical control. In this paper, the strategy of simultaneous EMG decoding of grasping patterns and grasping force was realized by controlling a virtual multi-degree-freedom prosthetic hand and a real one-degree-freedom prosthetic hand simultaneously. The former realized the grasping patterns from the recognition of the sEMG pattern. The other implemented the grasping force from sEMG force decoding. The results show that the control method is effective and feasible.

  17. A Grasp-Pose Generation Method Based on Gaussian Mixture Models

    Directory of Open Access Journals (Sweden)

    Wenjia Wu

    2015-11-01

    Full Text Available A Gaussian Mixture Model (GMM-based grasp-pose generation method is proposed in this paper. Through offline training, the GMM is set up and used to depict the distribution of the robot's reachable orientations. By dividing the robot's workspace into small 3D voxels and training the GMM for each voxel, a look-up table covering all the workspace is built with the x, y and z positions as the index and the GMM as the entry. Through the definition of Task Space Regions (TSR, an object's feasible grasp poses are expressed as a continuous region. With the GMM, grasp poses can be preferentially sampled from regions with high reachability probabilities in the online grasp-planning stage. The GMM can also be used as a preliminary judgement of a grasp pose's reachability. Experiments on both a simulated and a real robot show the superiority of our method over the existing method.

  18. Occupation and its relationship with health and wellbeing: the threshold concept for occupational therapy.

    Science.gov (United States)

    Fortune, Tracy; Kennedy-Jones, Mary

    2014-10-01

    We introduce the educational framework of 'threshold concepts' and discuss its utility in understanding the fundamental difficulties learners have in understanding ways of thinking and practising as occupational therapists. We propose that the relationship between occupation and health is a threshold concept for occupational therapy because of students' trouble in achieving lasting conceptual change in relation to their understanding of it. The authors present and discuss key ideas drawn from educational writings on threshold concepts, review the emerging literature on threshold concepts in occupational therapy, and pose a series of questions in order to prompt consideration of the pedagogical issues requiring action by academic and fieldwork educators. Threshold concepts in occupational therapy have been considered in a primarily cross-disciplinary sense, that is, the understandings that occupational therapy learners grapple with are relevant to learners in other disciplines. In contrast, we present a more narrowly defined conception that emphasises the 'bounded-ness' of the concept to the discipline. A threshold concept that captures the essential nature of occupational therapy is likely to be (highly) troublesome in terms of a learner's acquisition of it. Rather than simplifying these learning 'jewels' educators are encouraged to sit with the discomfort that they and the learner may experience as the learner struggles to grasp them. Moreover, they should reshape their curricula to provoke such struggles if transformative learning is to be the outcome. © 2014 Occupational Therapy Australia.

  19. Independent in the heard: Inclusion and exclusion as social processes. Proceedings from the 9th GRASP conference, Linköping University, May 2014 : Independent in the heard: Inclusion and exclusion as social processes. The 9th GRASP conference, Linköping University, May 2014

    OpenAIRE

    2014-01-01

    GRASP (Group and Social Psychology) is an interdisciplinary conference, which aims to provide a community around social psychological issues for researchers, practitioners, and graduate students from the Nordic countries within the fields of psychology, sociology, education, behavioural sciences and social work to share, exchange, learn, and develop preliminary results, new concepts, ideas, principles, and methodologies, as well as bridging the gaps between paradigms, encouraging interdiscipl...

  20. ANALYSIS of Control Force Grasping for a Multifunctional Five Fingered Robot to Pick-up Various of Components

    Directory of Open Access Journals (Sweden)

    Widhiada W.

    2016-01-01

    Full Text Available Multi-fingered robot gripper has become popular in the major research topics as grasping an object in robotic systems. The author considers a matter of style-based control model for a multi-fingered robot hand grasping an object with a known geometric characteristics. This paper introduces design process and analysis of contact force the five fingered gripper suitable to handle several of objects. The author applied Simulink/SimMechanics, Support package Arduino and Inventor software packages to facilatate and integrated the design of contact force gripper systems. The advance of PID control is used to control dynamics motions of the five fingered gripper systems. The multifunction finger’s gripper is developed to handle the various components. Contact force between fingertips and object surface is computed using the Hooke law concept. The analysis of experiment result shows the optimum of contact forces are achieved to hold the object. The spring and damper algorithm is used to compute the interaction of force between fingertips and object surface.

  1. Concept - or no concept

    DEFF Research Database (Denmark)

    Thorsteinsson, Uffe

    1999-01-01

    Discussion about concept in industrial companies. A method for mapping of managerial concept in specific area is shown......Discussion about concept in industrial companies. A method for mapping of managerial concept in specific area is shown...

  2. Grasps Recognition and Evaluation of Stroke Patients for Supporting Rehabilitation Therapy

    Directory of Open Access Journals (Sweden)

    Beatriz Leon

    2014-01-01

    Full Text Available Stroke survivors often suffer impairments on their wrist and hand. Robot-mediated rehabilitation techniques have been proposed as a way to enhance conventional therapy, based on intensive repeated movements. Amongst the set of activities of daily living, grasping is one of the most recurrent. Our aim is to incorporate the detection of grasps in the machine-mediated rehabilitation framework so that they can be incorporated into interactive therapeutic games. In this study, we developed and tested a method based on support vector machines for recognizing various grasp postures wearing a passive exoskeleton for hand and wrist rehabilitation after stroke. The experiment was conducted with ten healthy subjects and eight stroke patients performing the grasping gestures. The method was tested in terms of accuracy and robustness with respect to intersubjects’ variability and differences between different grasps. Our results show reliable recognition while also indicating that the recognition accuracy can be used to assess the patients’ ability to consistently repeat the gestures. Additionally, a grasp quality measure was proposed to measure the capabilities of the stroke patients to perform grasp postures in a similar way than healthy people. These two measures can be potentially used as complementary measures to other upper limb motion tests.

  3. Grasping Force Control for a Robotic Hand by Slip Detection Using Developed Micro Laser Doppler Velocimeter

    Directory of Open Access Journals (Sweden)

    Nobutomo Morita

    2018-01-01

    Full Text Available The purpose of this paper is to show the feasibility of grasping force control by feeding back signals of the developed micro-laser Doppler velocimeter (μ-LDV and by discriminating whether a grasped object is slipping or not. LDV is well known as a high response surface velocity sensor which can measure various surfaces—such as metal, paper, film, and so on—thus suggesting the potential application of LDV as a slip sensor for grasping various objects. However, the use of LDV as a slip sensor has not yet been reported because the size of LDVs is too large to be installed on a robotic fingertip. We have solved the size problem and enabled the performance of a feasibility test with a few-millimeter-scale LDV referred to as micro-LDV (μ-LDV by modifying the design which was adopted from MEMS (microelectromechanical systems fabrication process. In this paper, by applying our developed μ-LDV as a slip sensor, we have successfully demonstrated grasping force control with three target objects—aluminum block, wood block, and white acrylic block—considering that various objects made of these materials can be found in homes and factories, without grasping force feedback. We provide proofs that LDV is a new promising candidate slip sensor for grasping force control to execute target grasping.

  4. Grasping Force Control for a Robotic Hand by Slip Detection Using Developed Micro Laser Doppler Velocimeter.

    Science.gov (United States)

    Morita, Nobutomo; Nogami, Hirofumi; Higurashi, Eiji; Sawada, Renshi

    2018-01-23

    The purpose of this paper is to show the feasibility of grasping force control by feeding back signals of the developed micro-laser Doppler velocimeter (μ-LDV) and by discriminating whether a grasped object is slipping or not. LDV is well known as a high response surface velocity sensor which can measure various surfaces-such as metal, paper, film, and so on-thus suggesting the potential application of LDV as a slip sensor for grasping various objects. However, the use of LDV as a slip sensor has not yet been reported because the size of LDVs is too large to be installed on a robotic fingertip. We have solved the size problem and enabled the performance of a feasibility test with a few-millimeter-scale LDV referred to as micro-LDV (μ-LDV) by modifying the design which was adopted from MEMS (microelectromechanical systems) fabrication process. In this paper, by applying our developed μ-LDV as a slip sensor, we have successfully demonstrated grasping force control with three target objects-aluminum block, wood block, and white acrylic block-considering that various objects made of these materials can be found in homes and factories, without grasping force feedback. We provide proofs that LDV is a new promising candidate slip sensor for grasping force control to execute target grasping.

  5. Motivational state, reward value, and Pavlovian cues differentially affect skilled forelimb grasping in rats

    Science.gov (United States)

    de Clauser, Larissa; Kasper, Hansjörg; Schwab, Martin E.

    2016-01-01

    Motor skills represent high-precision movements performed at optimal speed and accuracy. Such motor skills are learned with practice over time. Besides practice, effects of motivation have also been shown to influence speed and accuracy of movements, suggesting that fast movements are performed to maximize gained reward over time as noted in previous studies. In rodents, skilled motor performance has been successfully modeled with the skilled grasping task, in which animals use their forepaw to grasp for sugar pellet rewards through a narrow window. Using sugar pellets, the skilled grasping task is inherently tied to motivation processes. In the present study, we performed three experiments modulating animals’ motivation during skilled grasping by changing the motivational state, presenting different reward value ratios, and displaying Pavlovian stimuli. We found in all three studies that motivation affected the speed of skilled grasping movements, with the strongest effects seen due to motivational state and reward value. Furthermore, accuracy of the movement, measured in success rate, showed a strong dependence on motivational state as well. Pavlovian cues had only minor effects on skilled grasping, but results indicate an inverse Pavlovian-instrumental transfer effect on movement speed. These findings have broad implications considering the increasing use of skilled grasping in studies of motor system structure, function, and recovery after injuries. PMID:27194796

  6. A novel algorithm for fast grasping of unknown objects using C-shape configuration

    Science.gov (United States)

    Lei, Qujiang; Chen, Guangming; Meijer, Jonathan; Wisse, Martijn

    2018-02-01

    Increasing grasping efficiency is very important for the robots to grasp unknown objects especially subjected to unfamiliar environments. To achieve this, a new algorithm is proposed based on the C-shape configuration. Specifically, the geometric model of the used under-actuated gripper is approximated as a C-shape. To obtain an appropriate graspable position, this C-shape configuration is applied to fit geometric model of an unknown object. The geometric model of unknown object is constructed by using a single-view partial point cloud. To examine the algorithm using simulations, a comparison of the commonly used motion planners is made. The motion planner with the highest number of solved runs, lowest computing time and the shortest path length is chosen to execute grasps found by this grasping algorithm. The simulation results demonstrate that excellent grasping efficiency is achieved by adopting our algorithm. To validate this algorithm, experiment tests are carried out using a UR5 robot arm and an under-actuated gripper. The experimental results show that steady grasping actions are obtained. Hence, this research provides a novel algorithm for fast grasping of unknown objects.

  7. Monocular-Based 6-Degree of Freedom Pose Estimation Technology for Robotic Intelligent Grasping Systems

    Directory of Open Access Journals (Sweden)

    Tao Liu

    2017-02-01

    Full Text Available Industrial robots are expected to undertake ever more advanced tasks in the modern manufacturing industry, such as intelligent grasping, in which robots should be capable of recognizing the position and orientation of a part before grasping it. In this paper, a monocular-based 6-degree of freedom (DOF pose estimation technology to enable robots to grasp large-size parts at informal poses is proposed. A camera was mounted on the robot end-flange and oriented to measure several featured points on the part before the robot moved to grasp it. In order to estimate the part pose, a nonlinear optimization model based on the camera object space collinearity error in different poses is established, and the initial iteration value is estimated with the differential transformation. Measuring poses of the camera are optimized based on uncertainty analysis. Also, the principle of the robotic intelligent grasping system was developed, with which the robot could adjust its pose to grasp the part. In experimental tests, the part poses estimated with the method described in this paper were compared with those produced by a laser tracker, and results show the RMS angle and position error are about 0.0228° and 0.4603 mm. Robotic intelligent grasping tests were also successfully performed in the experiments.

  8. Definition of the key target volume in radiosurgical management of arteriovenous malformations: a new dynamic concept based on angiographic circulation time.

    Science.gov (United States)

    Valle, Ramiro Del; Zenteno, Marco; Jaramillo, José; Lee, Angel; De Anda, Salvador

    2008-12-01

    The cumulative experience worldwide indicates complete radiosurgical obliteration rates of brain arteriovenous malformations (AVMs) ranging from 35 to 90%. The purpose of this study was to propose a strategy to increase the obliteration rate for AVMs through the dynamic definition of the key target volume (KTV). A prospective series of patients harboring an AVM was assessed using digital subtraction angiography in which a digital counter was used to measure the several stages of the frame-by-frame circulation time. All the patients were analyzed using dynamic measurement planning to define the KTV, corresponding to the volume of the shunt with the least vascular resistance and the earliest venous drainage. All patients underwent catheter-based angiography, a subgroup was additionally assessed by means of a superselective catheterization, and among these a further subgroup received embolization. The shunts were also categorized according to their angioarchitectural type: fistulous, plexiform, or mixed. The authors applied the radiosurgery-based grading system (RBGS) as well to find a correlation with the obliteration rate. This series includes 44 patients treated by radiosurgery; global angiography was performed for all patients, including dynamic measurement planning. Eighty-four percent of them underwent superselective catheterization, and 50% of the total population underwent embolization. In the embolized arm of the study, the pretreatment volume was up to 120 ml. In patients with a single treatment, the mean volume was 8.5 ml, and the median volume was 6.95 +/- 4.56 ml (mean +/- standard deviation), with a KTV of up to 15 ml. For prospectively staged radiosurgery, the mean KTV was 28 ml. The marginal radiation dose was 18-22 Gy, with a mean of dose 20 Gy. The mean RBGS score was 1.70. The overall obliteration rate was 91%, including the repeated radiosurgery group (4 patients), in which 100% showed complete obliteration. The overall permanent deficit was 2 of

  9. Biorthogonal moment expansions in coupled-cluster theory: Review of key concepts and merging the renormalized and active-space coupled-cluster methods

    International Nuclear Information System (INIS)

    Shen Jun; Piecuch, Piotr

    2012-01-01

    Graphical abstract: The key ideas behind biorthogonal moment expansions in coupled-cluster theory are discussed. Methods that enable merging active-space and renormalized coupled-cluster approaches are proposed and tested. Abstract: After reviewing recent progress in the area of the development of coupled-cluster (CC) methods for quasi-degenerate electronic states that are characterized by stronger non-dynamical correlation effects, including new generations of single- and multi-reference approaches that can handle bond breaking and excited states dominated by many-electron transitions, and after discussing the key elements of the left-eigenstate completely renormalized (CR) CC and equation-of-motion (EOM) CC methods, and the underlying biorthogonal method of moments of CC (MMCC) equations [P. Piecuch, M. Włoch, J. Chem. Phys. 123 (2005) 224105; P. Piecuch, M. Włoch, J.R. Gour, A. Kinal, Chem. Phys. Lett. 418 (2006) 467; M. Włoch, M.D. Lodriguito, P. Piecuch, J.R. Gour, Mol. Phys. 104 (2006) 2149], it is argued that it is beneficial to merge the CR-CC/EOMCC and active-space CC/EOMCC [P. Piecuch, Mol. Phys. 108 (2010) 2987, and references therein] theories into a single formalism. In order to accomplish this goal, the biorthogonal MMCC theory, which provides compact many-body expansions for the differences between the full configuration interaction and CC or, in the case of excited states, EOMCC energies, obtained using conventional truncation schemes in the cluster operator T and excitation operator R μ , is generalized, so that one can correct the CC/EOMCC energies obtained with arbitrary truncations in T and R μ for the selected many-electron correlation effects of interest. The resulting moment expansions, defining the new, Flexible MMCC (Flex-MMCC) formalism, and the ensuing CC(P; Q) hierarchy, proposed in the present work, enable one to correct energies obtained in the active-space CC and EOMCC calculations, in which one selects higher many

  10. Emergent coordination underlying learning to reach to grasp with a brain-machine interface.

    Science.gov (United States)

    Vaidya, Mukta; Balasubramanian, Karthikeyan; Southerland, Joshua; Badreldin, Islam; Eleryan, Ahmed; Shattuck, Kelsey; Gururangan, Suchin; Slutzky, Marc; Osborne, Leslie; Fagg, Andrew; Oweiss, Karim; Hatsopoulos, Nicholas G

    2018-04-01

    The development of coordinated reach-to-grasp movement has been well studied in infants and children. However, the role of motor cortex during this development is unclear because it is difficult to study in humans. We took the approach of using a brain-machine interface (BMI) paradigm in rhesus macaques with prior therapeutic amputations to examine the emergence of novel, coordinated reach to grasp. Previous research has shown that after amputation, the cortical area previously involved in the control of the lost limb undergoes reorganization, but prior BMI work has largely relied on finding neurons that already encode specific movement-related information. In this study, we taught macaques to cortically control a robotic arm and hand through operant conditioning, using neurons that were not explicitly reach or grasp related. Over the course of training, stereotypical patterns emerged and stabilized in the cross-covariance between the reaching and grasping velocity profiles, between pairs of neurons involved in controlling reach and grasp, and to a comparable, but lesser, extent between other stable neurons in the network. In fact, we found evidence of this structured coordination between pairs composed of all combinations of neurons decoding reach or grasp and other stable neurons in the network. The degree of and participation in coordination was highly correlated across all pair types. Our approach provides a unique model for studying the development of novel, coordinated reach-to-grasp movement at the behavioral and cortical levels. NEW & NOTEWORTHY Given that motor cortex undergoes reorganization after amputation, our work focuses on training nonhuman primates with chronic amputations to use neurons that are not reach or grasp related to control a robotic arm to reach to grasp through the use of operant conditioning, mimicking early development. We studied the development of a novel, coordinated behavior at the behavioral and cortical level, and the neural

  11. A novel device for grasping assessment during functional tasks: preliminary results

    Directory of Open Access Journals (Sweden)

    Ana Carolinne Portela Rocha

    2016-02-01

    Full Text Available This paper presents a methodology and first results obtained in a study with a novel device that allows the analysis of grasping quality. Such a device is able to acquire motion information of upper limbs allowing kinetic of manipulation analysis as well. A pilot experiment was carried out with six groups of typically developing children aged between 5 and 10 years old, with 7-8 children in each one. The device, designed to emulate a glass, has an optical system composed by one digital camera and a special convex mirror that together allow image acquisition of grasping hand posture when it is grasped and manipulated. It also carries an Inertial Measurement Unit (IMU that captures motion data as acceleration, orientation, and angular velocities. The novel instrumented object is used in our approach to evaluate functional tasks performance in quantitative terms. During tests each child was invited to grasp the cylindrical part of the device that was placed on the top of a table, simulating the task of drinking a glass of water. In the sequence the child was oriented to transport the device back to the starting position and release it. The task was repeated 3 times for each child. A grasping hand posture evaluation is presented as an example to evaluate grasping quality. Additionally, motion patterns obtained with the triasl performed with the different groups are presented and discussed. This device is attractive due to its portable characteristics, the small size and its ability to evaluate grasping form. The results may be also useful to analyze the evolution of the rehabilitation process through reach-to-grasping movement and the grasping images analysis.

  12. VisGraB: A Benchmark for Vision-Based Grasping. Paladyn Journal of Behavioral Robotics

    DEFF Research Database (Denmark)

    Kootstra, Gert; Popovic, Mila; Jørgensen, Jimmy Alison

    2012-01-01

    that a large number of grasps can be executed and evaluated while dealing with dynamics and the noise and uncertainty present in the real world images. VisGraB enables a fair comparison among different grasping methods. The user furthermore does not need to deal with robot hardware, focusing on the vision......We present a database and a software tool, VisGraB, for benchmarking of methods for vision-based grasping of unknown objects with no prior object knowledge. The benchmark is a combined real-world and simulated experimental setup. Stereo images of real scenes containing several objects in different...

  13. Learning to Grasp Unknown Objects Based on 3D Edge Information

    DEFF Research Database (Denmark)

    Bodenhagen, Leon; Kraft, Dirk; Popovic, Mila

    2010-01-01

    In this work we refine an initial grasping behavior based on 3D edge information by learning. Based on a set of autonomously generated evaluated grasps and relations between the semi-global 3D edges, a prediction function is learned that computes a likelihood for the success of a grasp using either...... an offline or an online learning scheme. Both methods are implemented using a hybrid artificial neural network containing standard nodes with a sigmoid activation function and nodes with a radial basis function. We show that a significant performance improvement can be achieved....

  14. Statistical Identification of Composed Visual Features Indicating High Likelihood of Grasp Success

    DEFF Research Database (Denmark)

    Thomsen, Mikkel Tang; Bodenhagen, Leon; Krüger, Norbert

    2013-01-01

    configurations of three 3D surface features that predict grasping actions with a high success probability. The strategy is based on first computing spatial relations between visual entities and secondly, exploring the cross-space of these relational feature space and grasping actions. The data foundation...... for identifying such indicative feature constellations is generated in a simulated environment wherein visual features are extracted and a large amount of grasping actions are evaluated through dynamic simulation. Based on the identified feature constellations, we validate by applying the acquired knowledge...

  15. Fuzzy Logic Controller Design for A Robot Grasping System with Different Membership Functions

    International Nuclear Information System (INIS)

    Ahmad, Hamzah; Razali, Saifudin; Mohamed, Mohd Rusllim

    2013-01-01

    This paper investigates the effects of the membership function to the object grasping for a three fingered gripper system. The performance of three famously used membership functions is compared to identify their behavior in lifting a defined object shape. MATLAB Simulink and SimMechanics toolboxes are used to examine the performance. Our preliminary results proposed that the Gaussian membership function surpassed the two other membership functions; triangular and trapezoid memberships especially in the context of firmer grasping and less time consumption during operations. Therefore, Gaussian membership function could be the best solution when time consumption and firmer grasp are considered

  16. Biorthogonal moment expansions in coupled-cluster theory: Review of key concepts and merging the renormalized and active-space coupled-cluster methods

    Science.gov (United States)

    Shen, Jun; Piecuch, Piotr

    2012-06-01

    After reviewing recent progress in the area of the development of coupled-cluster (CC) methods for quasi-degenerate electronic states that are characterized by stronger non-dynamical correlation effects, including new generations of single- and multi-reference approaches that can handle bond breaking and excited states dominated by many-electron transitions, and after discussing the key elements of the left-eigenstate completely renormalized (CR) CC and equation-of-motion (EOM) CC methods, and the underlying biorthogonal method of moments of CC (MMCC) equations [P. Piecuch, M. Włoch, J. Chem. Phys. 123 (2005) 224105; P. Piecuch, M. Włoch, J.R. Gour, A. Kinal, Chem. Phys. Lett. 418 (2006) 467; M. Włoch, M.D. Lodriguito, P. Piecuch, J.R. Gour, Mol. Phys. 104 (2006) 2149], it is argued that it is beneficial to merge the CR-CC/EOMCC and active-space CC/EOMCC [P. Piecuch, Mol. Phys. 108 (2010) 2987, and references therein] theories into a single formalism. In order to accomplish this goal, the biorthogonal MMCC theory, which provides compact many-body expansions for the differences between the full configuration interaction and CC or, in the case of excited states, EOMCC energies, obtained using conventional truncation schemes in the cluster operator T and excitation operator Rμ, is generalized, so that one can correct the CC/EOMCC energies obtained with arbitrary truncations in T and Rμ for the selected many-electron correlation effects of interest. The resulting moment expansions, defining the new, Flexible MMCC (Flex-MMCC) formalism, and the ensuing CC(P; Q) hierarchy, proposed in the present work, enable one to correct energies obtained in the active-space CC and EOMCC calculations, in which one selects higher many-body components of T and Rμ via active orbitals and which recover much of the relevant non-dynamical and some dynamical electron correlation effects in applications involving potential energy surfaces (PESs) along bond breaking coordinates, for the

  17. Closed-loop control of grasping with a myoelectric hand prosthesis: which are the relevant feedback variables for force control?

    Science.gov (United States)

    Ninu, Andrei; Dosen, Strahinja; Muceli, Silvia; Rattay, Frank; Dietl, Hans; Farina, Dario

    2014-09-01

    In closed-loop control of grasping by hand prostheses, the feedback information sent to the user is usually the actual controlled variable, i.e., the grasp force. Although this choice is intuitive and logical, the force production is only the last step in the process of grasping. Therefore, this study evaluated the performance in controlling grasp strength using a hand prosthesis operated through a complete grasping sequence while varying the feedback variables (e.g., closing velocity, grasping force), which were provided to the user visually or through vibrotactile stimulation. The experiments were conducted on 13 volunteers who controlled the Otto Bock Sensor Hand Speed prosthesis. Results showed that vibrotactile patterns were able to replace the visual feedback. Interestingly, the experiments demonstrated that direct force feedback was not essential for the control of grasping force. The subjects were indeed able to control the grip strength, predictively, by estimating the grasping force from the prosthesis velocity of closing. Therefore, grasping without explicit force feedback is not completely blind, contrary to what is usually assumed. In our study we analyzed grasping with a specific prosthetic device, but the outcomes are also applicable for other devices, with one or more degrees-of-freedom. The necessary condition is that the electromyography (EMG) signal directly and proportionally controls the velocity/grasp force of the hand, which is a common approach among EMG controlled prosthetic devices. The results provide important indications on the design of closed-loop EMG controlled prosthetic systems.

  18. Passive reach and grasp with functional electrical stimulation and robotic arm support

    NARCIS (Netherlands)

    Westerveld, Ard J.; Schouten, Alfred C.; Veltink, Peter H.; van der Kooij, Herman

    2014-01-01

    Rehabilitation of arm and hand function is crucial to increase functional independence of stroke subjects. Here, we investigate the technical feasibility of an integrated training system combining robotics and functional electrical stimulation (FES) to support reach and grasp during functional

  19. Manipulation of Unknown Objects to Improve the Grasp Quality Using Tactile Information.

    Science.gov (United States)

    Montaño, Andrés; Suárez, Raúl

    2018-05-03

    This work presents a novel and simple approach in the area of manipulation of unknown objects considering both geometric and mechanical constraints of the robotic hand. Starting with an initial blind grasp, our method improves the grasp quality through manipulation considering the three common goals of the manipulation process: improving the hand configuration, the grasp quality and the object positioning, and, at the same time, prevents the object from falling. Tactile feedback is used to obtain local information of the contacts between the fingertips and the object, and no additional exteroceptive feedback sources are considered in the approach. The main novelty of this work lies in the fact that the grasp optimization is performed on-line as a reactive procedure using the tactile and kinematic information obtained during the manipulation. Experimental results are shown to illustrate the efficiency of the approach.

  20. A Strategy for Grasping unknown Objects based on Co-Planarity and Colour Information

    DEFF Research Database (Denmark)

    Popovic, Mila; Kraft, Dirk; Bodenhagen, Leon

    2010-01-01

    with a reasonable success rate in rather complex environments (i.e., cluttered scenes with multiple objects). Moreover, we have embedded the algorithm within a cognitive system that allows for autonomous exploration and learning in different contexts. First, the system is able to perform long action sequences which......, although the grasping attempts not being always successful, can recover from mistakes and more importantly, is able to evaluate the success of the grasps autonomously by haptic feedback (i.e., by a force torque sensor at the wrist and proprioceptive information about the distance of the gripper after...... a gasping attempt). Such labelled data is then used for improving the initially hard-wired algorithm by learning. Moreover, the grasping behaviour has been used in a cognitive system to trigger higher level processes such as object learning and learning of object specific grasping....

  1. The visual neuroscience of robotic grasping achieving sensorimotor skills through dorsal-ventral stream integration

    CERN Document Server

    Chinellato, Eris

    2016-01-01

    This book presents interdisciplinary research that pursues the mutual enrichment of neuroscience and robotics. Building on experimental work, and on the wealth of literature regarding the two cortical pathways of visual processing - the dorsal and ventral streams - we define and implement, computationally and on a real robot, a functional model of the brain areas involved in vision-based grasping actions. Grasping in robotics is largely an unsolved problem, and we show how the bio-inspired approach is successful in dealing with some fundamental issues of the task. Our robotic system can safely perform grasping actions on different unmodeled objects, denoting especially reliable visual and visuomotor skills. The computational model and the robotic experiments help in validating theories on the mechanisms employed by the brain areas more directly involved in grasping actions. This book offers new insights and research hypotheses regarding such mechanisms, especially for what concerns the interaction between the...

  2. Phase dependence of transport-aperture coordination variability reveals control strategy of reach-to-grasp movements.

    Science.gov (United States)

    Rand, Miya K; Shimansky, Y P; Hossain, Abul B M I; Stelmach, George E

    2010-11-01

    Based on an assumption of movement control optimality in reach-to-grasp movements, we have recently developed a mathematical model of transport-aperture coordination (TAC), according to which the hand-target distance is a function of hand velocity and acceleration, aperture magnitude, and aperture velocity and acceleration (Rand et al. in Exp Brain Res 188:263-274, 2008). Reach-to-grasp movements were performed by young adults under four different reaching speeds and two different transport distances. The residual error magnitude of fitting the above model to data across different trials and subjects was minimal for the aperture-closure phase, but relatively much greater for the aperture-opening phase, indicating considerable difference in TAC variability between those phases. This study's goal is to identify the main reasons for that difference and obtain insights into the control strategy of reach-to-grasp movements. TAC variability within the aperture-opening phase of a single trial was found minimal, indicating that TAC variability between trials was not due to execution noise, but rather a result of inter-trial and inter-subject variability of motor plan. At the same time, the dependence of the extent of trial-to-trial variability of TAC in that phase on the speed of hand transport was sharply inconsistent with the concept of speed-accuracy trade-off: the lower the speed, the larger the variability. Conversely, the dependence of the extent of TAC variability in the aperture-closure phase on hand transport speed was consistent with that concept. Taking into account recent evidence that the cost of neural information processing is substantial for movement planning, the dependence of TAC variability in the aperture-opening phase on task performance conditions suggests that it is not the movement time that the CNS saves in that phase, but the cost of neuro-computational resources and metabolic energy required for TAC regulation in that phase. Thus, the CNS

  3. Design and fabrication of robotic gripper for grasping in minimizing contact force

    Science.gov (United States)

    Heidari, Hamidreza; Pouria, Milad Jafary; Sharifi, Shahriar; Karami, Mahmoudreza

    2018-03-01

    This paper presents a new method to improve the kinematics of robot gripper for grasping in unstructured environments, such as space operations. The robot gripper is inspired from the human hand and kept the hand design close to the structure of human fingers to provide successful grasping capabilities. The main goal is to improve kinematic structure of gripper to increase the grasping capability of large objects, decrease the contact forces and makes a successful grasp of various objects in unstructured environments. This research will describe the development of a self-adaptive and reconfigurable robotic hand for space operations through mechanical compliance which is versatile, robust and easy to control. Our model contains two fingers, two-link and three-link, with combining a kinematic model of thumb index. Moreover, some experimental tests are performed to examine the effectiveness of the hand-made in real, unstructured tasks. The results represent that the successful grasp range is improved about 30% and the contact forces is reduced approximately 10% for a wide range of target object size. According to the obtained results, the proposed approach provides an accommodative kinematic model which makes the better grasping capability by fingers geometries for a robot gripper.

  4. Grasp planning for a reconfigurable parallel robot with an underactuated arm structure

    Directory of Open Access Journals (Sweden)

    M. Riedel

    2010-12-01

    Full Text Available In this paper, a novel approach of grasp planning is applied to find out the appropriate grasp points for a reconfigurable parallel robot called PARAGRIP (Parallel Gripping. This new handling system is able to manipulate objects in the six-dimensional Cartesian space by several robotic arms using only six actuated joints. After grasping, the contact elements at the end of the underactuated arm mechanisms are connected to the object which forms a closed loop mechanism similar to the architecture of parallel manipulators. As the mounting and grasp points of the arms can easily be changed, the manipulator can be reconfigured to match the user's preferences and needs. This paper raises the question, how and where these grasp points are to be placed on the object to perform well for a certain manipulation task.

    This paper was presented at the IFToMM/ASME International Workshop on Underactuated Grasping (UG2010, 19 August 2010, Montréal, Canada.

  5. Preschool children adapt grasping movements to upcoming object manipulations: Evidence from a dial rotation task.

    Science.gov (United States)

    Herbort, Oliver; Büschelberger, Juliane; Janczyk, Markus

    2018-03-01

    In adults, the motor plans for object-directed grasping movements reflects the anticipated requirements of intended future object manipulations. This prospective mode of planning has been termed second-order planning. Surprisingly, second-order planning is thought to be fully developed only by 10 years of age, when children master seemingly more complex motor skills. In this study, we tested the hypothesis that already 5- and 6-year-old children consistently use second-order planning but that this ability does not become apparent in tasks that are traditionally used to probe it. We asked 5- and 6-year-olds and adults to grasp and rotate a circular dial in a clockwise or counterclockwise direction. Although children's grasp selections were less consistent on an intra- and inter-individual level than adults' grasp selections, all children adjusted their grasps to the upcoming dial rotations. By contrast, in an also administered bar rotation task, only a subset of children adjusted their grasps to different bar rotations, thereby replicating previous results. The results indicate that 5- and 6-year-olds consistently use second-order planning in a dial rotation task, although this ability does not become apparent in bar rotation tasks. Copyright © 2017 Elsevier Inc. All rights reserved.

  6. Dependence of behavioral performance on material category in an object grasping task with monkeys.

    Science.gov (United States)

    Yokoi, Isao; Tachibana, Atsumichi; Minamimoto, Takafumi; Goda, Naokazu; Komatsu, Hidehiko

    2018-05-02

    Material perception is an essential part of our cognitive function that enables us to properly interact with our complex daily environment. One important aspect of material perception is its multimodal nature. When we see an object, we generally recognize its haptic properties as well as its visual properties. Consequently, one must examine behavior using real objects that are perceived both visually and haptically to fully understand the characteristics of material perception. As a first step, we examined whether there is any difference in the behavioral responses to different materials in monkeys trained to perform an object grasping task in which they saw and grasped rod-shaped real objects made of various materials. We found that the monkeys' behavior in the grasping task, measured based on the success rate and the pulling force, differed depending on the material category. Monkeys easily and correctly grasped objects of some materials, such as metal and glass, but failed to grasp objects of other materials. In particular, monkeys avoided grasping fur-covered objects. The differences in the behavioral responses to the material categories cannot be explained solely based on the degree of familiarity with the different materials. These results shed light on the organization of multimodal representation of materials, where their biological significance is an important factor. In addition, a monkey that avoided touching real fur-covered objects readily touched images of the same objects presented on a CRT display. This suggests employing real objects is important when studying behaviors related to material perception.

  7. Human grasping database for activities of daily living with depth, color and kinematic data streams.

    Science.gov (United States)

    Saudabayev, Artur; Rysbek, Zhanibek; Khassenova, Raykhan; Varol, Huseyin Atakan

    2018-05-29

    This paper presents a grasping database collected from multiple human subjects for activities of daily living in unstructured environments. The main strength of this database is the use of three different sensing modalities: color images from a head-mounted action camera, distance data from a depth sensor on the dominant arm and upper body kinematic data acquired from an inertial motion capture suit. 3826 grasps were identified in the data collected during 9-hours of experiments. The grasps were grouped according to a hierarchical taxonomy into 35 different grasp types. The database contains information related to each grasp and associated sensor data acquired from the three sensor modalities. We also provide our data annotation software written in Matlab as an open-source tool. The size of the database is 172 GB. We believe this database can be used as a stepping stone to develop big data and machine learning techniques for grasping and manipulation with potential applications in rehabilitation robotics and intelligent automation.

  8. Functional morphology of the hallucal metatarsal with implications for inferring grasping ability in extinct primates.

    Science.gov (United States)

    Goodenberger, Katherine E; Boyer, Doug M; Orr, Caley M; Jacobs, Rachel L; Femiani, John C; Patel, Biren A

    2015-03-01

    Primate evolutionary morphologists have argued that selection for life in a fine branch niche resulted in grasping specializations that are reflected in the hallucal metatarsal (Mt1) morphology of extant "prosimians", while a transition to use of relatively larger, horizontal substrates explains the apparent loss of such characters in anthropoids. Accordingly, these morphological characters-Mt1 torsion, peroneal process length and thickness, and physiological abduction angle-have been used to reconstruct grasping ability and locomotor mode in the earliest fossil primates. Although these characters are prominently featured in debates on the origin and subsequent radiation of Primates, questions remain about their functional significance. This study examines the relationship between these morphological characters of the Mt1 and a novel metric of pedal grasping ability for a large number of extant taxa in a phylogenetic framework. Results indicate greater Mt1 torsion in taxa that engage in hallucal grasping and in those that utilize relatively small substrates more frequently. This study provides evidence that Carpolestes simpsoni has a torsion value more similar to grasping primates than to any scandentian. The results also show that taxa that habitually grasp vertical substrates are distinguished from other taxa in having relatively longer peroneal processes. Furthermore, a longer peroneal process is also correlated with calcaneal elongation, a metric previously found to reflect leaping proclivity. A more refined understanding of the functional associations between Mt1 morphology and behavior in extant primates enhances the potential for using these morphological characters to comprehend primate (locomotor) evolution. © 2014 Wiley Periodicals, Inc.

  9. New version: GRASP2K relativistic atomic structure package

    Science.gov (United States)

    Jönsson, P.; Gaigalas, G.; Bieroń, J.; Fischer, C. Froese; Grant, I. P.

    2013-09-01

    A revised version of GRASP2K [P. Jönsson, X. He, C. Froese Fischer, I.P. Grant, Comput. Phys. Commun. 177 (2007) 597] is presented. It supports earlier non-block and block versions of codes as well as a new block version in which the njgraf library module [A. Bar-Shalom, M. Klapisch, Comput. Phys. Commun. 50 (1988) 375] has been replaced by the librang angular package developed by Gaigalas based on the theory of [G. Gaigalas, Z.B. Rudzikas, C. Froese Fischer, J. Phys. B: At. Mol. Phys. 30 (1997) 3747, G. Gaigalas, S. Fritzsche, I.P. Grant, Comput. Phys. Commun. 139 (2001) 263]. Tests have shown that errors encountered by njgraf do not occur with the new angular package. The three versions are denoted v1, v2, and v3, respectively. In addition, in v3, the coefficients of fractional parentage have been extended to j=9/2, making calculations feasible for the lanthanides and actinides. Changes in v2 include minor improvements. For example, the new version of rci2 may be used to compute quantum electrodynamic (QED) corrections only from selected orbitals. In v3, a new program, jj2lsj, reports the percentage composition of the wave function in LSJ and the program rlevels has been modified to report the configuration state function (CSF) with the largest coefficient of an LSJ expansion. The bioscl2 and bioscl3 application programs have been modified to produce a file of transition data with one record for each transition in the same format as in ATSP2K [C. Froese Fischer, G. Tachiev, G. Gaigalas, M.R. Godefroid, Comput. Phys. Commun. 176 (2007) 559], which identifies each atomic state by the total energy and a label for the CSF with the largest expansion coefficient in LSJ intermediate coupling. All versions of the codes have been adapted for 64-bit computer architecture. Program SummaryProgram title: GRASP2K, version 1_1 Catalogue identifier: ADZL_v1_1 Program summary URL: http://cpc.cs.qub.ac.uk/summaries/ADZL_v1_1.html Program obtainable from: CPC Program Library

  10. Engage key social concepts for sustainability

    Science.gov (United States)

    C. C. Hicks; A. Levine; A. Agrawal; X. Basurto; S. J. Breslow; C. Carothers; Susan Charnley; S. Coulthard; N. Dolsak; J. Donatuto; C. Garcia-Quijano; M. B. Mascia; K. Norman; M. R. Poe; T. Satterfield; K. St. Martin; P. S. Levin

    2016-01-01

    With humans altering climate processes, biogeochemical cycles, and ecosystem functions (1), governments and societies confront the challenge of shaping a sustainable future for people and nature. Policies and practices to address these challenges must draw on social sciences, along with natural sciences and engineering (2). Although various social science approaches...

  11. An object-identity probability cueing paradigm during grasping observation: the facilitating effect is present only when the observed kinematics is suitable for the cued object.

    Science.gov (United States)

    Craighero, Laila; Mele, Sonia; Zorzi, Valentina

    2015-01-01

    Electrophysiological and psychophysical data indicate that grasping observation automatically orients attention toward the incoming interactions between the actor's hand and the object. The aim of the present study was to clarify if this effect facilitates the detection of a graspable object with the observed action as compared to an ungraspable one. We submitted participants to an object-identity probability cueing experiment in which the two possible targets were of the same dimensions but one of them presented sharp tips at one extreme while the other presented flat faces. At the beginning of each trial the most probable target was briefly shown. After a variable interval, at the same position, the same (75%) or a different target (25%) was presented. Participants had to press a key in response to target appearance. Superimposed to the video showing cue and target, an agent performing the reaching and grasping of the target was presented. The kinematics of the action was or was not suitable for grasping the cued target, according to the absence or presence of the sharp tips. Results showed that response was modulated by the probability of target identity but only when the observed kinematics was suitable to grasp the attended target. A further experiment clarified that response modulation was never present when the superimposed video always showed the agent at a rest position. These findings are discussed at the light of neurophysiological and psychophysical literature, considering the relationship between the motor system and the perception of objects and of others' actions. We conclude that the prediction of the mechanical events that arise from the interactions between the hand and the attended object is at the basis of the capability to select a graspable object in space.

  12. Optimal grasp planning for a dexterous robotic hand using the volume of a generalized force ellipsoid during accepted flattening

    Directory of Open Access Journals (Sweden)

    Peng Jia

    2017-01-01

    Full Text Available A grasp planning method based on the volume and flattening of a generalized force ellipsoid is proposed to improve the grasping ability of a dexterous robotic hand. First, according to the general solution of joint torques for a dexterous robotic hand, a grasping indicator for the dexterous hand—the maximum volume of a generalized external force ellipsoid and the minimum volume of a generalized contact internal force ellipsoid during accepted flattening—is proposed. Second, an optimal grasp planning method based on a task is established using the grasping indicator as an objective function. Finally, a simulation analysis and grasping experiment are performed. Results show that when the grasping experiment is conducted with the grasping configuration and positions of contact points optimized using the proposed grasping indicator, the root-mean-square values of the joint torques and contact internal forces of the dexterous hand are at a minimum. The effectiveness of the proposed grasping planning method is thus demonstrated.

  13. Concatenation of observed grasp phases with observer's distal movements: a behavioural and TMS study.

    Directory of Open Access Journals (Sweden)

    Elisa De Stefani

    Full Text Available The present study aimed at determining how actions executed by two conspecifics can be coordinated with each other, or more specifically, how the observation of different phases of a reaching-grasping action is temporary related to the execution of a movement of the observer. Participants observed postures of initial finger opening, maximal finger aperture, and final finger closing of grasp after observation of an initial hand posture. Then, they opened or closed their right thumb and index finger (experiments 1, 2 and 3. Response times decreased, whereas acceleration and velocity of actual finger movements increased when observing the two late phases of grasp. In addition, the results ruled out the possibility that this effect was due to salience of the visual stimulus when the hand was close to the target and confirmed an effect of even hand postures in addition to hand apparent motion due to the succession of initial hand posture and grasp phase. In experiments 4 and 5, the observation of grasp phases modulated even foot movements and pronunciation of syllables. Finally, in experiment 6, transcranial magnetic stimulation applied to primary motor cortex 300 ms post-stimulus induced an increase in hand motor evoked potentials of opponens pollicis muscle when observing the two late phases of grasp. These data suggest that the observation of grasp phases induced simulation which was stronger during observation of finger closing. This produced shorter response times, greater acceleration and velocity of the successive movement. In general, our data suggest best concatenation between two movements (one observed and the other executed when the observed (and simulated movement was to be accomplished. The mechanism joining the observation of a conspecific's action with our own movement may be precursor of social functions. It may be at the basis for interactions between conspecifics, and related to communication between individuals.

  14. Concatenation of observed grasp phases with observer's distal movements: a behavioural and TMS study.

    Science.gov (United States)

    De Stefani, Elisa; Innocenti, Alessandro; De Marco, Doriana; Gentilucci, Maurizio

    2013-01-01

    The present study aimed at determining how actions executed by two conspecifics can be coordinated with each other, or more specifically, how the observation of different phases of a reaching-grasping action is temporary related to the execution of a movement of the observer. Participants observed postures of initial finger opening, maximal finger aperture, and final finger closing of grasp after observation of an initial hand posture. Then, they opened or closed their right thumb and index finger (experiments 1, 2 and 3). Response times decreased, whereas acceleration and velocity of actual finger movements increased when observing the two late phases of grasp. In addition, the results ruled out the possibility that this effect was due to salience of the visual stimulus when the hand was close to the target and confirmed an effect of even hand postures in addition to hand apparent motion due to the succession of initial hand posture and grasp phase. In experiments 4 and 5, the observation of grasp phases modulated even foot movements and pronunciation of syllables. Finally, in experiment 6, transcranial magnetic stimulation applied to primary motor cortex 300 ms post-stimulus induced an increase in hand motor evoked potentials of opponens pollicis muscle when observing the two late phases of grasp. These data suggest that the observation of grasp phases induced simulation which was stronger during observation of finger closing. This produced shorter response times, greater acceleration and velocity of the successive movement. In general, our data suggest best concatenation between two movements (one observed and the other executed) when the observed (and simulated) movement was to be accomplished. The mechanism joining the observation of a conspecific's action with our own movement may be precursor of social functions. It may be at the basis for interactions between conspecifics, and related to communication between individuals.

  15. Concatenation of Observed Grasp Phases with Observer’s Distal Movements: A Behavioural and TMS Study

    Science.gov (United States)

    De Stefani, Elisa; Innocenti, Alessandro; De Marco, Doriana; Gentilucci, Maurizio

    2013-01-01

    The present study aimed at determining how actions executed by two conspecifics can be coordinated with each other, or more specifically, how the observation of different phases of a reaching-grasping action is temporary related to the execution of a movement of the observer. Participants observed postures of initial finger opening, maximal finger aperture, and final finger closing of grasp after observation of an initial hand posture. Then, they opened or closed their right thumb and index finger (experiments 1, 2 and 3). Response times decreased, whereas acceleration and velocity of actual finger movements increased when observing the two late phases of grasp. In addition, the results ruled out the possibility that this effect was due to salience of the visual stimulus when the hand was close to the target and confirmed an effect of even hand postures in addition to hand apparent motion due to the succession of initial hand posture and grasp phase. In experiments 4 and 5, the observation of grasp phases modulated even foot movements and pronunciation of syllables. Finally, in experiment 6, transcranial magnetic stimulation applied to primary motor cortex 300 ms post-stimulus induced an increase in hand motor evoked potentials of opponens pollicis muscle when observing the two late phases of grasp. These data suggest that the observation of grasp phases induced simulation which was stronger during observation of finger closing. This produced shorter response times, greater acceleration and velocity of the successive movement. In general, our data suggest best concatenation between two movements (one observed and the other executed) when the observed (and simulated) movement was to be accomplished. The mechanism joining the observation of a conspecific’s action with our own movement may be precursor of social functions. It may be at the basis for interactions between conspecifics, and related to communication between individuals. PMID:24278395

  16. How Weight Affects the Perceived Spacing between the Thumb and Fingers during Grasping.

    Directory of Open Access Journals (Sweden)

    Annie A Butler

    Full Text Available We know much about mechanisms determining the perceived size and weight of lifted objects, but little about how these properties of size and weight affect the body representation (e.g. grasp aperture of the hand. Without vision, subjects (n = 16 estimated spacing between fingers and thumb (perceived grasp aperture while lifting canisters of the same width (6.6cm but varied weights (300, 600, 900, and 1200 g. Lifts were performed by movement of either the wrist, elbow or shoulder to examine whether lifting with different muscle groups affects the judgement of grasp aperture. Results for perceived grasp aperture were compared with changes in perceived weight of objects of different sizes (5.2, 6.6, and 10 cm but the same weight (600 g. When canisters of the same width but different weights were lifted, perceived grasp aperture decreased 4.8% [2.2 ‒ 7.4] (mean [95% CI]; P < 0.001 from the lightest to the heaviest canister, no matter how they were lifted. For objects of the same weight but different widths, perceived weight decreased 42.3% [38.2 ‒ 46.4] from narrowest to widest (P < 0.001, as expected from the size-weight illusion. Thus, despite a highly distorted perception of the weight of objects based on their size, we conclude that proprioceptive afferents maintain a reasonably stable perception of the aperture of the grasping hand over a wide range of object weights. Given the small magnitude of this 'weight-grasp aperture' illusion, we propose the brain has access to a relatively stable 'perceptual ruler' to aid the manipulation of different objects.

  17. Patterns of muscle activity underlying object-specific grasp by the macaque monkey.

    Science.gov (United States)

    Brochier, T; Spinks, R L; Umilta, M A; Lemon, R N

    2004-09-01

    During object grasp, a coordinated activation of distal muscles is required to shape the hand in relation to the physical properties of the object. Despite the fundamental importance of the grasping action, little is known of the muscular activation patterns that allow objects of different sizes and shapes to be grasped. In a study of two adult macaque monkeys, we investigated whether we could distinguish between EMG activation patterns associated with grasp of 12 differently shaped objects, chosen to evoke a wide range of grasping postures. Each object was mounted on a horizontal shuttle held by a weak spring (load force 1-2 N). Objects were located in separate sectors of a "carousel," and inter-trial rotation of the carousel allowed sequential presentation of the objects in pseudorandom order. EMG activity from 10 to 12 digit, hand, and arm muscles was recorded using chronically implanted electrodes. We show that the grasp of different objects was characterized by complex but distinctive patterns of EMG activation. Cluster analysis shows that these object-related EMG patterns were specific and consistent enough to identify the object unequivocally from the EMG recordings alone. EMG-based object identification required a minimum of six EMGs from simultaneously recorded muscles. EMG patterns were consistent across recording sessions in a given monkey but showed some differences between animals. These results identify the specific patterns of activity required to achieve distinct hand postures for grasping, and they open the way to our understanding of how these patterns are generated by the central motor network.

  18. Grip type and task goal modify reach-to-grasp performance in post-stroke hemiparesis

    Science.gov (United States)

    Schaefer, Sydney Y.; DeJong, Stacey L.; Cherry, Kendra M.; Lang, Catherine E.

    2011-01-01

    This study investigated whether grip type and/or task goal influenced reaching and grasping performance in post-stroke hemiparesis. Sixteen adults with post-stroke hemiparesis and twelve healthy adults reached to and grasped a cylindrical object using one of two grip types (3-finger or palmar) to achieve one of two task goals (hold or lift). Performance of the stroke group was characteristic of hemiparetic limb movement during reach-to-grasp, with more curved handpaths and slower velocities compared to the control group. These effects were present regardless of grip type or task goal. Other measures of reaching (reach time and reach velocity at object contact) and grasping (peak thumb-index finger aperture during the reach and peak grip force during the grasp) were differentially affected by grip type, task goal, or both, despite the presence of hemiparesis, providing new evidence that changes in motor patterns after stroke may occur to compensate for stroke-related motor impairment. PMID:22357103

  19. Continuous grasp algorithm applied to economic dispatch problem of thermal units

    Energy Technology Data Exchange (ETDEWEB)

    Vianna Neto, Julio Xavier [Pontifical Catholic University of Parana - PUCPR, Curitiba, PR (Brazil). Undergraduate Program at Mechatronics Engineering; Bernert, Diego Luis de Andrade; Coelho, Leandro dos Santos [Pontifical Catholic University of Parana - PUCPR, Curitiba, PR (Brazil). Industrial and Systems Engineering Graduate Program, LAS/PPGEPS], e-mail: leandro.coelho@pucpr.br

    2010-07-01

    The economic dispatch problem (EDP) is one of the fundamental issues in power systems to obtain benefits with the stability, reliability and security. Its objective is to allocate the power demand among committed generators in the most economical manner, while all physical and operational constraints are satisfied. The cost of power generation, particularly in fossil fuel plants, is very high and economic dispatch helps in saving a significant amount of revenue. Recently, as an alternative to the conventional mathematical approaches, modern heuristic optimization techniques such as simulated annealing, evolutionary algorithms, neural networks, ant colony, and tabu search have been given much attention by many researchers due to their ability to find an almost global optimal solution in EDPs. On other hand, continuous GRASP (C-GRASP) is a stochastic local search meta-heuristic for finding cost-efficient solutions to continuous global optimization problems subject to box constraints. Like a greedy randomized adaptive search procedure (GRASP), a C-GRASP is a multi-start procedure where a starting solution for local improvement is constructed in a greedy randomized fashion. The C-GRASP algorithm is validated for a test system consisting of fifteen units, test system that takes into account spinning reserve and prohibited operating zones constrains. (author)

  20. Viewing geometry determines the contribution of binocular vision to the online control of grasping.

    Science.gov (United States)

    Keefe, Bruce D; Watt, Simon J

    2017-12-01

    Binocular vision is often assumed to make a specific, critical contribution to online visual control of grasping by providing precise information about the separation between digits and object. This account overlooks the 'viewing geometry' typically encountered in grasping, however. Separation of hand and object is rarely aligned precisely with the line of sight (the visual depth dimension), and analysis of the raw signals suggests that, for most other viewing angles, binocular feedback is less precise than monocular feedback. Thus, online grasp control relying selectively on binocular feedback would not be robust to natural changes in viewing geometry. Alternatively, sensory integration theory suggests that different signals contribute according to their relative precision, in which case the role of binocular feedback should depend on viewing geometry, rather than being 'hard-wired'. We manipulated viewing geometry, and assessed the role of binocular feedback by measuring the effects on grasping of occluding one eye at movement onset. Loss of binocular feedback resulted in a significantly less extended final slow-movement phase when hand and object were separated primarily in the frontoparallel plane (where binocular information is relatively imprecise), compared to when they were separated primarily along the line of sight (where binocular information is relatively precise). Consistent with sensory integration theory, this suggests the role of binocular (and monocular) vision in online grasp control is not a fixed, 'architectural' property of the visuo-motor system, but arises instead from the interaction of viewer and situation, allowing robust online control across natural variations in viewing geometry.

  1. Grasping the thistle: The role of alcohol brief interventions in Scottish alcohol policy.

    Science.gov (United States)

    Graham, Lesley J C; Mackinnon, Donna

    2010-11-01

    Scotland has experienced a substantial rise in alcohol-related harm, which is now one of the biggest public health challenges it faces. Alcohol problems in Scotland are described along with national alcohol policy response in addressing them. The role of a program of Alcohol Brief Interventions is discussed therein. In Scotland, considerable proportions of the population are drinking hazardously or harmfully, common across different age and socioeconomic groups. Rising consumption has been set in wider environmental changes with alcohol becoming more available and affordable. Scotland has had one of the fastest growing chronic liver disease mortality rates in the world at a time when rates in most of Western Europe are falling. Scotland's alcohol policy has an explicit aim to reduce population consumption and includes legislative measures to tackle price and availability. A national program to deliver Alcohol Brief Interventions for hazardous drinkers is a key plank of this wider strategy. A portfolio of studies will monitor and evaluate national policy and, through contribution analysis, describe the role Alcohol Brief Interventions play in reducing alcohol misuse. Effective alcohol policy recognises that determinants of health not only lie at individual level, but include wider social, environmental and economic factors. Scotland's policy is addressing these determinants with both population-based and population-targeted interventions. Scotland has a serious problem with alcohol. A comprehensive, evidence-based, resourced alcohol policy is being implemented, which will need continual review to ensure it remains anchored in evidence while maintaining its ambition.[Graham LJC, MacKinnon D. GRASPING THE THISTLE: The role of alcohol brief interventions in Scottish alcohol policy. © 2010 Australasian Professional Society on Alcohol and other Drugs.

  2. Comparison is key.

    Science.gov (United States)

    Stone, Mark H; Stenner, A Jackson

    2014-01-01

    Several concepts from Georg Rasch's last papers are discussed. The key one is comparison because Rasch considered the method of comparison fundamental to science. From the role of comparison stems scientific inference made operational by a properly developed frame of reference producing specific objectivity. The exact specifications Rasch outlined for making comparisons are explicated from quotes, and the role of causality derived from making comparisons is also examined. Understanding causality has implications for what can and cannot be produced via Rasch measurement. His simple examples were instructive, but the implications are far reaching upon first establishing the key role of comparison.

  3. Etymology as an Aid to Understanding Chemistry Concepts

    Science.gov (United States)

    Sarma, Nittala S.

    2004-01-01

    Learning the connection between the roots and the chemical meaning of terms can improve students' understanding of chemistry concepts, making them easier and more enjoyable to master. The way in which using etymology to understand the meanings and relationships of chemistry terms can aid students in strengthening and expanding their grasp of…

  4. Identifying Threshold Concepts for Information Literacy: A Delphi Study

    Science.gov (United States)

    Townsend, Lori; Hofer, Amy R.; Hanick, Silvia Lin; Brunetti, Korey

    2016-01-01

    This study used the Delphi method to engage expert practitioners on the topic of threshold concepts--core ideas and processes in a discipline that students need to grasp in order to progress in their learning, but that are often unspoken or unrecognized by expert practitioners--for information literacy. A panel of experts considered two questions:…

  5. Manipulating Models and Grasping the Ideas They Represent

    Science.gov (United States)

    Bryce, T. G. K.; Blown, E. J.

    2016-03-01

    This article notes the convergence of recent thinking in neuroscience and grounded cognition regarding the way we understand mental representation and recollection: ideas are dynamic and multi-modal, actively created at the point of recall. Also, neurophysiologically, re-entrant signalling among cortical circuits allows non-conscious processing to support our deliberative thoughts and actions. The qualitative research we describe examines the exchanges occurring during semi-structured interviews with 360 children age 3-13, including 294 from New Zealand (158 boys, 136 girls) and 66 from China (34 boys, 32 girls) concerning their understanding of the shape and motion of the Earth, Sun and Moon (ESM). We look closely at the relationships between what is revealed as children manipulate their own play-dough models and their apparent understandings of ESM concepts. In particular, we focus on the switching taking place between what is said, what is drawn and what is modelled. The evidence is supportive of Edelman's view that memory is non-representational and that concepts are the outcome of perceptual mappings, a view which is also in accord with Barsalou's notion that concepts are simulators or skills which operate consistently across several modalities. Quantitative data indicate that the dynamic structure of memory/concept creation is similar in both genders and common to the cultures/ethnicities compared (New Zealand European and Māori; Chinese Han) and that repeated interviews in this longitudinal research lead to more advanced modelling skills and/or more advanced shape and motion concepts, the results supporting hypotheses ( Kolmogorov- Smirnov alpha levels .05; r s : p < .001).

  6. Grasping and manipulation of deformable objects based on internal force requirements

    Directory of Open Access Journals (Sweden)

    Sohil Garg

    2008-11-01

    Full Text Available In this paper an analysis of grasping and manipulation of deformable objects by a three finger robot hand has been carried out. It is proved that the required fingertip grasping forces and velocities vary with change in object size due to deformation. The variation of the internal force with the change in fingertip and object contact angle has been investigated in detail. From the results it is concluded that it is very difficult to manipulate an object if the finger contact angle is not between 30 o and 70 o, as the internal forces or velocities become very large outside this range. Hence even if the object is inside the work volume of the three fingers it would still not be possible to manipulate it. A simple control model is proposed which can control the grasping and manipulation of a deformable object. Experimental results are also presented to prove the proposed method.

  7. GRASP2: visualization, surface properties, and electrostatics of macromolecular structures and sequences.

    Science.gov (United States)

    Petrey, Donald; Honig, Barry

    2003-01-01

    The widespread use of the original version of GRASP revealed the importance of the visualization of physicochemical and structural properties on the molecular surface. This chapter describes a new version of GRASP that contains many new capabilities. In terms of analysis tools, the most notable new features are sequence and structure analysis and alignment tools and the graphical integration of sequence and structural information. Not all the new GRASP2 could be described here and more capabilities are continually being added. An on-line manual, details on obtaining the software, and technical notes about the program and the Troll software library can be found at the Honig laboratory Web site (http://trantor.bioc.columbia.edu).

  8. From a meso- to micro-scale connectome: Array Tomography and mGRASP

    Directory of Open Access Journals (Sweden)

    Jinhyun eKim

    2015-06-01

    Full Text Available Mapping mammalian synaptic connectivity has long been an important goal of neuroscience because knowing how neurons and brain areas are connected underpins an understanding of brain function. Meeting this goal requires advanced techniques with single synapse resolution and large-scale capacity, especially at multiple scales tethering the meso- and micro-scale connectome. Among several advanced LM-based connectome technologies, Array Tomography (AT and mammalian GFP-Reconstitution Across Synaptic Partners (mGRASP can provide relatively high-throughput mapping synaptic connectivity at multiple scales. AT- and mGRASP-assisted circuit mapping (ATing and mGRASPing, combined with techniques such as retrograde virus, brain clearing techniques, and activity indicators will help unlock the secrets of complex neural circuits. Here, we discuss these useful new tools to enable mapping of brain circuits at multiple scales, some functional implications of spatial synaptic distribution, and future challenges and directions of these endeavors.

  9. Impaired anticipatory control of grasp during obstacle crossing in Parkinson's disease.

    Science.gov (United States)

    McIsaac, Tara L; Diermayr, Gudrun; Albert, Frederic

    2012-05-16

    During self-paced walking, people with Parkinson's disease maintain anticipatory control during object grasping. However, common functional tasks often include carrying an object while changing step patterns mid-path and maneuvering over obstacles, increasing task complexity and attentional demands. Thus, the present study investigated the effect of Parkinson's disease on the modulation of grasping force changes as a function of gait-related inertial forces. Subjects with Parkinson's disease maintained the ability to scale and to couple over time their grip and inertial forces while walking at irregular step lengths, but were unable to maintain the temporal coupling of grasping forces compared to controls during obstacle crossing. We suggest that this deterioration in anticipatory control is associated with the increased demands of task complexity and attention during obstacle crossing. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  10. Neurons in Primary Motor Cortex Encode Hand Orientation in a Reach-to-Grasp Task.

    Science.gov (United States)

    Ma, Chaolin; Ma, Xuan; Fan, Jing; He, Jiping

    2017-08-01

    It is disputed whether those neurons in the primary motor cortex (M1) that encode hand orientation constitute an independent channel for orientation control in reach-to-grasp behaviors. Here, we trained two monkeys to reach forward and grasp objects positioned in the frontal plane at different orientation angles, and simultaneously recorded the activity of M1 neurons. Among the 2235 neurons recorded in M1, we found that 18.7% had a high correlation exclusively with hand orientation, 15.9% with movement direction, and 29.5% with both movement direction and hand orientation. The distributions of neurons encoding hand orientation and those encoding movement direction were not uniform but coexisted in the same region. The trajectory of hand rotation was reproduced by the firing patterns of the orientation-related neurons independent of the hand reaching direction. These results suggest that hand orientation is an independent component for the control of reaching and grasping activity.

  11. Research on Visual Servo Grasping of Household Objects for Nonholonomic Mobile Manipulator

    Directory of Open Access Journals (Sweden)

    Huangsheng Xie

    2014-01-01

    Full Text Available This paper focuses on the problem of visual servo grasping of household objects for nonholonomic mobile manipulator. Firstly, a new kind of artificial object mark based on QR (Quick Response Code is designed, which can be affixed to the surface of household objects. Secondly, after summarizing the vision-based autonomous mobile manipulation system as a generalized manipulator, the generalized manipulator’s kinematic model is established, the analytical inverse kinematic solutions of the generalized manipulator are acquired, and a novel active vision based camera calibration method is proposed to determine the hand-eye relationship. Finally, a visual servo switching control law is designed to control the service robot to finish object grasping operation. Experimental results show that QR Code-based artificial object mark can overcome the difficulties brought by household objects’ variety and operation complexity, and the proposed visual servo scheme makes it possible for service robot to grasp and deliver objects efficiently.

  12. A circular feature-based pose measurement method for metal part grasping

    International Nuclear Information System (INIS)

    Wu, Chenrui; He, Zaixing; Zhang, Shuyou; Zhao, Xinyue

    2017-01-01

    The grasping of circular metal parts such as bearings and flanges is a common task in industry. Limited by low texture and repeated features, the point-feature-based method is not applicable in pose measurement of these parts. In this paper, we propose a novel pose measurement method for grasping circular metal parts. This method is based on cone degradation and involves a monocular camera. To achieve higher measurement accuracy, a position-based visual servoing method is presented to continuously control an eye-in-hand, six-degrees-of-freedom robot arm to grasp the part. The uncertainty of the part’s coordinate frame during the control process is solved by defining a fixed virtual coordinate frame. Experimental results are provided to illustrate the effectiveness of the proposed method and the factors that affect measurement accuracy are analyzed. (paper)

  13. Bio-inspired grasp control in a robotic hand with massive sensorial input.

    Science.gov (United States)

    Ascari, Luca; Bertocchi, Ulisse; Corradi, Paolo; Laschi, Cecilia; Dario, Paolo

    2009-02-01

    The capability of grasping and lifting an object in a suitable, stable and controlled way is an outstanding feature for a robot, and thus far, one of the major problems to be solved in robotics. No robotic tools able to perform an advanced control of the grasp as, for instance, the human hand does, have been demonstrated to date. Due to its capital importance in science and in many applications, namely from biomedics to manufacturing, the issue has been matter of deep scientific investigations in both the field of neurophysiology and robotics. While the former is contributing with a profound understanding of the dynamics of real-time control of the slippage and grasp force in the human hand, the latter tries more and more to reproduce, or take inspiration by, the nature's approach, by means of hardware and software technology. On this regard, one of the major constraints robotics has to overcome is the real-time processing of a large amounts of data generated by the tactile sensors while grasping, which poses serious problems to the available computational power. In this paper a bio-inspired approach to tactile data processing has been followed in order to design and test a hardware-software robotic architecture that works on the parallel processing of a large amount of tactile sensing signals. The working principle of the architecture bases on the cellular nonlinear/neural network (CNN) paradigm, while using both hand shape and spatial-temporal features obtained from an array of microfabricated force sensors, in order to control the sensory-motor coordination of the robotic system. Prototypical grasping tasks were selected to measure the system performances applied to a computer-interfaced robotic hand. Successful grasps of several objects, completely unknown to the robot, e.g. soft and deformable objects like plastic bottles, soft balls, and Japanese tofu, have been demonstrated.

  14. The influence of grasping habits and object orientation on motor planning in children and adults.

    Science.gov (United States)

    Jovanovic, Bianca; Schwarzer, Gudrun

    2017-12-01

    We investigated the influence of habitual grasp strategies and object orientation on motor planning in 3-year-olds and 4- to 5-year-old children and adults. Participants were required to rotate different vertically oriented objects around 180°. Usually, adults perform this task by grasping objects with an awkward grip (thumb and index finger pointing downward) at the beginning of the movement, in order to finish it with a comfortable hand position. This pattern corresponds to the well-known end-state comfort effect (ESC) in grasp planning. The presented objects were associated with different habitual grasp orientations that either corresponded with the grasp direction required to reach end-state comfort (downward) or implied a contrary grasp orientation (upward). Additionally, they were presented either in their usual, canonical orientation (e.g., shovel with the blade oriented downward versus cup with its opening oriented upward) or upside down. As dependent variable we analyzed the number of grips conforming to the end-state comfort principle (ESC score) realized in each object type and orientation condition. The number of grips conforming to ESC strongly increased with age. In addition, the extent to which end-state comfort was considered was influenced by the actual orientation of the objects' functional parts. Thus, in all age-groups the ESC score was highest when the functional parts of the objects were oriented downward (shovel presented canonically with blade pointing downward, cup presented upside down) and corresponded to the hand orientation needed to realize ESC. © 2017 Wiley Periodicals, Inc.

  15. Infant manual performance during reaching and grasping for objects moving in depth.

    Science.gov (United States)

    Domellöf, Erik; Barbu-Roth, Marianne; Rönnqvist, Louise; Jacquet, Anne-Yvonne; Fagard, Jacqueline

    2015-01-01

    Few studies have investigated manual performance in infants when reaching and grasping for objects moving in directions other than across the fronto-parallel plane. The present preliminary study explored object-oriented behavioral strategies and side preference in 8- and 10-month-old infants during reaching and grasping for objects approaching in depth from three positions (midline, and 27° diagonally from the left and right). Effects of task constraint by using objects of three different types and two sizes were further examined for behavioral strategies and hand opening prior to grasping. Additionally, assessments of hand preference by a dedicated handedness test were performed. Regardless of object starting position, the 8-month-old infants predominantly displayed right-handed reaches for objects approaching in depth. In contrast, the older infants showed more varied strategies and performed more ipsilateral reaches in correspondence with the side of the approaching object. Conversely, 10-month-old infants were more successful than the younger infants in grasping the objects, independent of object starting position. The findings regarding infant hand use strategies when reaching and grasping for objects moving in depth are similar to those from earlier studies using objects moving along a horizontal path. Still, initiation times of reaching onset were generally long in the present study, indicating that the object motion paths seemingly affected how the infants perceived the intrinsic properties and spatial locations of the objects, possibly with an effect on motor planning. Findings are further discussed in relation to future investigations of infant reaching and grasping for objects approaching in depth.

  16. Infant manual performance during reaching and grasping for objects moving in depth

    Directory of Open Access Journals (Sweden)

    Erik eDomellöf

    2015-08-01

    Full Text Available Few studies have observed investigated manual asymmetries performance in infants when reaching and grasping for objects moving in directions other than across the fronto-parallel plane. The present preliminary study explored manual object-oriented behavioral strategies and hand side preference in 8- and 10-month-old infants during reaching and grasping for objects approaching in depth from three positions (midline, and 27° diagonally from the left, and right, midline. Effects of task constraint by using objects of three different types and two sizes were further examined for behavioral strategies and . The study also involved measurements of hand position opening prior to grasping., and Additionally, assessments of general hand preference by a dedicated handedness test were performed. Regardless of object starting position, the 8-month-old infants predominantly displayed right-handed reaches for objects approaching in depth. In contrast, the older infants showed more varied strategies and performed more ipsilateral reaches in correspondence with the side of the approaching object. Conversely, 10-month-old infants were more successful than the younger infants in grasping the objects, independent of object starting position. The findings support the possibility of a shared underlying mechanism regarding for infant hand use strategies when reaching and grasping for horizontally objects moving in depth are similar to those from earlier studies using objects moving along a horizontal pathand vertically moving objects. Still, initiation times of reaching onset were generally long in the present study, indicating that the object motion paths seemingly affected how the infants perceived the intrinsic properties and spatial locations of the objects, possibly with an effect on motor planning. Findings are further discussed in relation to future investigations of infant reaching and grasping for objects approaching in depth.

  17. Multisession, noninvasive closed-loop neuroprosthetic control of grasping by upper limb amputees.

    Science.gov (United States)

    Agashe, H A; Paek, A Y; Contreras-Vidal, J L

    2016-01-01

    Upper limb amputation results in a severe reduction in the quality of life of affected individuals due to their inability to easily perform activities of daily living. Brain-machine interfaces (BMIs) that translate grasping intent from the brain's neural activity into prosthetic control may increase the level of natural control currently available in myoelectric prostheses. Current BMI techniques demonstrate accurate arm position and single degree-of-freedom grasp control but are invasive and require daily recalibration. In this study we tested if transradial amputees (A1 and A2) could control grasp preshaping in a prosthetic device using a noninvasive electroencephalography (EEG)-based closed-loop BMI system. Participants attempted to grasp presented objects by controlling two grasping synergies, in 12 sessions performed over 5 weeks. Prior to closed-loop control, the first six sessions included a decoder calibration phase using action observation by the participants; thereafter, the decoder was fixed to examine neuroprosthetic performance in the absence of decoder recalibration. Ability of participants to control the prosthetic was measured by the success rate of grasping; ie, the percentage of trials within a session in which presented objects were successfully grasped. Participant A1 maintained a steady success rate (63±3%) across sessions (significantly above chance [41±5%] for 11 sessions). Participant A2, who was under the influence of pharmacological treatment for depression, hormone imbalance, pain management (for phantom pain as well as shoulder joint inflammation), and drug dependence, achieved a success rate of 32±2% across sessions (significantly above chance [27±5%] in only two sessions). EEG signal quality was stable across sessions, but the decoders created during the first six sessions showed variation, indicating EEG features relevant to decoding at a smaller timescale (100ms) may not be stable. Overall, our results show that (a) an EEG

  18. Tactile Gloves for Autonomous Grasping With the NASA/DARPA Robonaut

    Science.gov (United States)

    Martin, T. B.; Ambrose, R. O.; Diftler, M. A.; Platt, R., Jr.; Butzer, M. J.

    2004-01-01

    Tactile data from rugged gloves are providing the foundation for developing autonomous grasping skills for the NASA/DARPA Robonaut, a dexterous humanoid robot. These custom gloves compliment the human like dexterity available in the Robonaut hands. Multiple versions of the gloves are discussed, showing a progression in using advanced materials and construction techniques to enhance sensitivity and overall sensor coverage. The force data provided by the gloves can be used to improve dexterous, tool and power grasping primitives. Experiments with the latest gloves focus on the use of tools, specifically a power drill used to approximate an astronaut's torque tool.

  19. Students' Conceptions on White Light and Implications for Teaching and Learning about Colour

    Science.gov (United States)

    Haagen-Schützenhöfer, Claudia

    2017-01-01

    The quality of learning processes is mainly determined by the extent to which students' conceptions are addressed and thus conceptual change is triggered. Colour phenomena are a topic within initial instruction of optics which is challenging. A physically adequate concept of white light is crucial for being able to grasp the processes underlying…

  20. The Observation of Manual Grasp Actions Affects the Control of Speech: A Combined Behavioral and Transcranial Magnetic Stimulation Study

    Science.gov (United States)

    Gentilucci, Maurizio; Campione, Giovanna Cristina; Volta, Riccardo Dalla; Bernardis, Paolo

    2009-01-01

    Does the mirror system affect the control of speech? This issue was addressed in behavioral and Transcranial Magnetic Stimulation (TMS) experiments. In behavioral experiment 1, participants pronounced the syllable /da/ while observing (1) a hand grasping large and small objects with power and precision grasps, respectively, (2) a foot interacting…

  1. Picture this! grasping the dimensions of time and space

    CERN Document Server

    Carroll, Michael

    2016-01-01

    Astronomical concepts can be truly hard to comprehend, especially those of planetary sizes and distances from Earth and from each other. These concepts are made more comprehensible by the group of illustrations in this book, which put, in scale, side by side extraterrestrial objects with objects on Earth we can more easily relate to. For example, study the pictures of Earth floating above Jupiter’s Great Red Spot and the asteroid Itokawa resting beside Toronto’s CN Tower. These mind-bending images bring things better into perspective and will help you understand the size and scale of our Solar System. In later chapters, you will be told how close the visionaries of the past came to guessing what today’s explorers would find. Astronomer/painter Lucien Rudaux’s masterpieces of Mars dust storms anticipated Viking and Mars rover images by nearly a century. Space artist Ludek Pesek envisioned astronauts setting up camp on the lunar surface in scenes hauntingly similar to photos taken by Apollo a...

  2. The dynamics of God's reign as a hermeneutic key to Jesus ...

    African Journals Online (AJOL)

    With this study, we seek to contribute to the theological discussion regarding the nature and the meaning of the Christian eschaton. We will argue that the dynamics of God's reign provide a hermeneutic key to Jesus' 'eschatological expectation'. It is not possible to grasp the full meaning of Jesus' urgent expectation of the ...

  3. Classification of right-hand grasp movement based on EMOTIV Epoc+

    Science.gov (United States)

    Tobing, T. A. M. L.; Prawito, Wijaya, S. K.

    2017-07-01

    Combinations of BCT elements for right-hand grasp movement have been obtained, providing the average value of their classification accuracy. The aim of this study is to find a suitable combination for best classification accuracy of right-hand grasp movement based on EEG headset, EMOTIV Epoc+. There are three movement classifications: grasping hand, relax, and opening hand. These classifications take advantage of Event-Related Desynchronization (ERD) phenomenon that makes it possible to differ relaxation, imagery, and movement state from each other. The combinations of elements are the usage of Independent Component Analysis (ICA), spectrum analysis by Fast Fourier Transform (FFT), maximum mu and beta power with their frequency as features, and also classifier Probabilistic Neural Network (PNN) and Radial Basis Function (RBF). The average values of classification accuracy are ± 83% for training and ± 57% for testing. To have a better understanding of the signal quality recorded by EMOTIV Epoc+, the result of classification accuracy of left or right-hand grasping movement EEG signal (provided by Physionet) also be given, i.e.± 85% for training and ± 70% for testing. The comparison of accuracy value from each combination, experiment condition, and external EEG data are provided for the purpose of value analysis of classification accuracy.

  4. Dynamic optimal grasping of a circular object with gravity using robotic soft-fingertips

    Directory of Open Access Journals (Sweden)

    García-Rodríguez Rodolfo

    2016-06-01

    Full Text Available Object manipulation usually requires dexterity, encoded as the ability to roll, which is very difficult to achieve with robotic hands based on point contact models (subject to holonomic constraints. As an alternative for dexterous manipulation, deformable contact with hemispherical shape fingertips has been proposed to yield naturally a rolling constraint. It entails dexterity at the expense of dealing with normal and tangential forces, as well as more elaborated models and control schemes. Furthermore, the essential feature of the quality of grasp can be addressed with this type of robot hands, but it has been overlooked for deformable contact. In this paper, a passivity-based controller that considers an optimal grasping measure is proposed for robotic hands with hemispherical deformable fingertips, to manipulate circular dynamic objects. Optimal grasping that minimizes the contact wrenches is achieved through fingertip rolling until normal forces pass through the center of mass of the object, aligning the relative angle between these normal forces. The case of a circular object is developed in detail, though our proposal can be extended to objects with an arbitrary shape that admit a local decomposition by a circular curvature. Simulation and experimental results show convergence under various conditions, wherein rolling and tangent forces become instrumental to achieve such a quality of grasp.

  5. Electrotactile feedback improves performance and facilitates learning in the routine grasping task

    Directory of Open Access Journals (Sweden)

    Milica Isaković

    2016-06-01

    Full Text Available Aim of this study was to investigate the feasibility of electrotactile feedback in closed loop training of force control during the routine grasping task. The feedback was provided using an array electrode and a simple six-level spatial coding, and the experiment was conducted in three amputee subjects. The psychometric tests confirmed that the subjects could perceive and interpret the electrotactile feedback with a high success rate. The subjects performed the routine grasping task comprising 4 blocks of 60 grasping trials. In each trial, the subjects employed feedforward control to close the hand and produce the desired grasping force (four levels. First (baseline and the last (validation session were performed in open loop, while the second and the third session (training included electrotactile feedback. The obtained results confirmed that using the feedback improved the accuracy and precision of the force control. In addition, the subjects performed significantly better in the validation vs. baseline session, therefore suggesting that electrotactile feedback can be used for learning and training of myoelectric control.

  6. Electrotactile Feedback Improves Performance and Facilitates Learning in the Routine Grasping Task.

    Science.gov (United States)

    Isaković, Milica; Belić, Minja; Štrbac, Matija; Popović, Igor; Došen, Strahinja; Farina, Dario; Keller, Thierry

    2016-06-13

    Aim of this study was to investigate the feasibility of electrotactile feedback in closed loop training of force control during the routine grasping task. The feedback was provided using an array electrode and a simple six-level spatial coding, and the experiment was conducted in three amputee subjects. The psychometric tests confirmed that the subjects could perceive and interpret the electrotactile feedback with a high success rate. The subjects performed the routine grasping task comprising 4 blocks of 60 grasping trials. In each trial, the subjects employed feedforward control to close the hand and produce the desired grasping force (four levels). First (baseline) and the last (validation) session were performed in open loop, while the second and the third session (training) included electrotactile feedback. The obtained results confirmed that using the feedback improved the accuracy and precision of the force control. In addition, the subjects performed significantly better in the validation vs. baseline session, therefore suggesting that electrotactile feedback can be used for learning and training of myoelectric control.

  7. Prosthetic hand sensor placement: Analysis of touch perception during the grasp

    Directory of Open Access Journals (Sweden)

    Mirković Bojana

    2014-01-01

    Full Text Available Humans rely on their hands to perform everyday tasks. The hand is used as a tool, but also as the interface to “sense” the world. Current prosthetic hands are based on sophisticated multi-fingered structures, and include many sensors which counterpart natural proprioceptors and exteroceptors. The sensory information is used for control, but not sent to the user of the hand (amputee. Grasping without sensing is not good enough. This research is part of the development of the sensing interface for amputees, specifically addressing the analysis of human perception while grasping. The goal is to determine the small number of preferred positions of sensors on the prosthetic hand. This task has previously been approached by trying to replicate a natural sensory system characteristic for healthy humans, resulting in a multitude of redundant sensors and basic inability to make the patient aware of the sensor readings on the subconscious level. We based our artificial perception system on the reported sensations of humans when grasping various objects without seeing the objects (obstructed visual feedback. Subjects, with no known sensory deficits, were asked to report on the touch sensation while grasping. The analysis included objects of various sizes, weights, textures and temperatures. Based on this data we formed a map of the preferred positions for the sensors that is appropriate for five finger human-like robotic hand. The final map was intentionally minimized in size (number of sensors.

  8. Single-Grasp Object Classification and Feature Extraction with Simple Robot Hands and Tactile Sensors.

    Science.gov (United States)

    Spiers, Adam J; Liarokapis, Minas V; Calli, Berk; Dollar, Aaron M

    2016-01-01

    Classical robotic approaches to tactile object identification often involve rigid mechanical grippers, dense sensor arrays, and exploratory procedures (EPs). Though EPs are a natural method for humans to acquire object information, evidence also exists for meaningful tactile property inference from brief, non-exploratory motions (a 'haptic glance'). In this work, we implement tactile object identification and feature extraction techniques on data acquired during a single, unplanned grasp with a simple, underactuated robot hand equipped with inexpensive barometric pressure sensors. Our methodology utilizes two cooperating schemes based on an advanced machine learning technique (random forests) and parametric methods that estimate object properties. The available data is limited to actuator positions (one per two link finger) and force sensors values (eight per finger). The schemes are able to work both independently and collaboratively, depending on the task scenario. When collaborating, the results of each method contribute to the other, improving the overall result in a synergistic fashion. Unlike prior work, the proposed approach does not require object exploration, re-grasping, grasp-release, or force modulation and works for arbitrary object start positions and orientations. Due to these factors, the technique may be integrated into practical robotic grasping scenarios without adding time or manipulation overheads.

  9. Microsoft kinect-based artificial perception system for control of functional electrical stimulation assisted grasping.

    Science.gov (United States)

    Strbac, Matija; Kočović, Slobodan; Marković, Marko; Popović, Dejan B

    2014-01-01

    We present a computer vision algorithm that incorporates a heuristic model which mimics a biological control system for the estimation of control signals used in functional electrical stimulation (FES) assisted grasping. The developed processing software acquires the data from Microsoft Kinect camera and implements real-time hand tracking and object analysis. This information can be used to identify temporal synchrony and spatial synergies modalities for FES control. Therefore, the algorithm acts as artificial perception which mimics human visual perception by identifying the position and shape of the object with respect to the position of the hand in real time during the planning phase of the grasp. This artificial perception used within the heuristically developed model allows selection of the appropriate grasp and prehension. The experiments demonstrate that correct grasp modality was selected in more than 90% of tested scenarios/objects. The system is portable, and the components are low in cost and robust; hence, it can be used for the FES in clinical or even home environment. The main application of the system is envisioned for functional electrical therapy, that is, intensive exercise assisted with FES.

  10. TRANSGENIC STRATEGY FOR IDENTIFYING SYNAPTIC CONNECTIONS IN MICE BY FLUORESCENCE COMPLEMENTATION (GRASP

    Directory of Open Access Journals (Sweden)

    Masahito eYamagata

    2012-02-01

    Full Text Available In the "GFP reconstitution across synaptic partners" (GRASP method, non-fluorescent fragments of GFP are expressed in two different neurons; the fragments self-assemble at synapses between the two to form a fluorophore. GRASP has proven useful for light microscopic identification of synapses in two invertebrate species, Caenorhabditis elegans and Drosophila melanogaster, but has not yet been applied to vertebrates. Here, we describe GRASP constructs that function in mammalian cells and implement a transgenic strategy in which a Cre-dependent gene switch leads to expression of the two fragments in mutually exclusive neuronal subsets in mice. Using a transgenic line that expresses Cre selectively in rod photoreceptors, we demonstrate labeling of synapses in the outer plexiform layer of the retina. Labeling is specific, in that synapses made by rods remain labeled for at least 6 months whereas nearby synapses made by intercalated cone photoreceptors on many of the same interneurons remain unlabeled. We also generated antisera that label reconstituted GFP but neither fragment in order to amplify the GRASP signal and thereby increase the sensitivity of the method.

  11. A Sense of Touch in Laparoscopy : Using Augmented Haptic Feedback to Improve Grasp Control

    NARCIS (Netherlands)

    Westebring-van der Putten, E.P.

    2011-01-01

    Laparoscopy is Minimally Invasive Surgery (MIS) that is conducted in the belly alcove and which enables instruments, which enter the body through small incisions, to manipulate tissue. The possible complications arising during laparoscopic surgery are partly caused by improper grasp control on the

  12. How Do Object Size and Rigidity Affect Reaching and Grasping in Infants with Down Syndrome?

    Science.gov (United States)

    de Campos, Ana Carolina; Francisco, Kelly Regina; Savelsbergh, Geert J. P.; Rocha, Nelci Adriana Cicuto Ferreira

    2011-01-01

    Reaching and grasping skills have been described to emerge from a dynamic interaction between intrinsic and extrinsic factors. The purpose of the present study was to investigate the interaction between such an intrinsic factor, Down syndrome, and extrinsic factors, such as different object properties. Seven infants with Down syndrome and seven…

  13. Temporal-spatial parameters of the upper limb during a Reach & Grasp Cycle for children.

    Science.gov (United States)

    Butler, Erin E; Ladd, Amy L; Lamont, Lauren E; Rose, Jessica

    2010-07-01

    The objective of this study was to characterize normal temporal-spatial patterns during the Reach & Grasp Cycle and to identify upper limb motor deficits in children with cerebral palsy (CP). The Reach & Grasp Cycle encompasses six sequential tasks: reach, grasp cylinder, transport to self (T(1)), transport back to table (T(2)), release cylinder, and return to initial position. Three-dimensional motion data were recorded from 25 typically developing children (11 males, 14 females; ages 5-18 years) and 12 children with hemiplegic CP (2 males, 10 females; ages 5-17 years). Within-day and between-day coefficients of variation for the control group ranged from 0 to 0.19, indicating good repeatability of all parameters. The mean duration of the Cycle for children with CP was nearly twice as long as controls, 9.5±4.3s versus 5.1±1.2s (U=37.0, P=.002), partly due to prolonged grasp and release durations. Peak hand velocity occurred at approximately 40% of each phase and was greater during the transport (T(1), T(2)) than non-transport phases (reach, return) in controls (PGrasp Cycle (rho=.957, PGrasp Cycle for quantitative evaluation of upper limb motor deficits. Copyright © 2010 Elsevier B.V. All rights reserved.

  14. Exploration of Hand Grasp Patterns Elicitable Through Non-Invasive Proximal Nerve Stimulation.

    Science.gov (United States)

    Shin, Henry; Watkins, Zach; Hu, Xiaogang

    2017-11-29

    Various neurological conditions, such as stroke or spinal cord injury, result in an impaired control of the hand. One method of restoring this impairment is through functional electrical stimulation (FES). However, traditional FES techniques often lead to quick fatigue and unnatural ballistic movements. In this study, we sought to explore the capabilities of a non-invasive proximal nerve stimulation technique in eliciting various hand grasp patterns. The ulnar and median nerves proximal to the elbow joint were activated transcutanously using a programmable stimulator, and the resultant finger flexion joint angles were recorded using a motion capture system. The individual finger motions averaged across the three joints were analyzed using a cluster analysis, in order to classify the different hand grasp patterns. With low current intensity (grasp patterns including single finger movement and coordinated multi-finger movements. This study provides initial evidence on the feasibility of a proximal nerve stimulation technique in controlling a variety of finger movements and grasp patterns. Our approach could also be developed into a rehabilitative/assistive tool that can result in flexible movements of the fingers.

  15. Characteristics of grasping movements in a laboratory and in an everyday-like context.

    Science.gov (United States)

    Bock, Otmar; Züll, Anne

    2013-02-01

    To understand the principles of motor control, it is useful to know whether movements with the same physical constraints can be governed by different rules depending on the behavioral context. We therefore have recently introduced a paradigm in which subjects grasp from the same starting position to the same final object, once as a typical laboratory task and once as part of everyday-like behavior. In the laboratory context, grasping was repetitive, externally triggered and purposeless; in the everyday-like context, it was embedded in a complex activity, intentionally initiated, and served a purpose. Here we present a comprehensive analysis of data from that paradigm. Among 38 response parameters that reflected hand transport, grip shaping and object manipulation, 20 differed significantly between groups. Factor analysis further reduced them to four orthogonal factors: response speed, finger-object contact, response variability, and hand path curvature. This shows, for the first time, that behavioral context influences the execution of grasping movements in four independent ways, possibly reflecting four distinct functional modules in the motor system. This fits well with the view - derived from neurological data - that grasping is controlled by a set of interconnected brain areas which are differentially recruited to achieve different behavioral goals. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Grasp Learning by Means of Developing Sensorimotor Schemas and Generic World Knowledge

    DEFF Research Database (Denmark)

    Krüger, Norbert; Popovic, Mila; Bodenhagen, Leon

    2011-01-01

    We present a cognitive system in which grasping competences are coded by means of a formalisation of sensory motor schemas in terms of so called ‘object action complexes’ (OACs). OACs define the knowledge of the system via the effects and precondition of certain behavioural patterns, and also code...

  17. Playing With Nonverbal Communication: Using Grasp and Facial Direction to Create Adaptive Interaction in a Game

    DEFF Research Database (Denmark)

    Mortensen, Ditte Hvas; Bærentsen, Klaus B.

    2014-01-01

    . The results indicate that participants grasp a remote control according to the intended use and turn their face towards the object with which they intend to interact. The amount of time during which the participants turned their faces towards the object was influenced by the available visual information...

  18. Capacity of small groups of muscles to accomplish precision grasping tasks.

    Science.gov (United States)

    Towles, Joseph D; Valero-Cuevas, Francisco J; Hentz, Vincent R

    2013-01-01

    An understanding of the capacity or ability of various muscle groups to generate endpoint forces that enable grasping tasks could provide a stronger biomechanical basis for the design of reconstructive surgery or rehabilitation for the treatment of the paralyzed or paretic hand. We quantified two-dimensional endpoint force distributions for every combination of the muscles of the index finger, in cadaveric specimens, to understand the capability of muscle groups to produce endpoint forces that accomplish three common types of grasps-tripod, tip and lateral pinch-characterized by a representative level of Coulomb friction. We found that muscle groups of 4 or fewer muscles were capable of generating endpoint forces that enabled performance of each of the grasping tasks examined. We also found that flexor muscles were crucial to accomplish tripod pinch; intrinsic muscles, tip pinch; and the dorsal interosseus muscle, lateral pinch. The results of this study provide a basis for decision making in the design of reconstructive surgeries and rehabilitation approaches that attempt to restore the ability to perform grasping tasks with small groups of muscles.

  19. Grasp: Tracing, visualizing and measuring the behavior of real-time systems

    NARCIS (Netherlands)

    Holenderski, M.J.; Heuvel, van den M.M.H.P.; Bril, R.J.; Lukkien, J.J.; Lipari, G.; Cucinotta, T.

    2010-01-01

    Understanding and validating the timing behavior of real-time systems is not trivial. Many real-time operating systems and their development environments do not provide tracing support, and provide only limited visualization, measurements and analysis tools. This paper presents Grasp, a tool for

  20. The GRASP 3: Graphical Reliability Analysis Simulation Program. Version 3: A users' manual and modelling guide

    Science.gov (United States)

    Phillips, D. T.; Manseur, B.; Foster, J. W.

    1982-01-01

    Alternate definitions of system failure create complex analysis for which analytic solutions are available only for simple, special cases. The GRASP methodology is a computer simulation approach for solving all classes of problems in which both failure and repair events are modeled according to the probability laws of the individual components of the system.

  1. Grasping the other's attention: The role of animacy in action cueing of joint attention

    NARCIS (Netherlands)

    Lindemann, O.; Nuku, P.; Rüschemeyer, S.A.; Bekkering, H.

    2011-01-01

    The current experiment investigates the role of animacy on grasp-cueing effects as investigated in joint attention research. In a simple detection task participants responded to the colour change of one of two objects of identical size. Before the target onset, we presented a cueing stimulus

  2. Research of grasping algorithm based on scara industrial robot

    Science.gov (United States)

    Peng, Tao; Zuo, Ping; Yang, Hai

    2018-04-01

    As the tobacco industry grows, facing the challenge of the international tobacco giant, efficient logistics service is one of the key factors. How to complete the tobacco sorting task of efficient economy is the goal of tobacco sorting and optimization research. Now the cigarette distribution system uses a single line to carry out the single brand sorting task, this article adopts a single line to realize the cigarette sorting task of different brands. Using scara robot special algorithm for sorting and packaging, the optimization scheme significantly enhances the indicators of smoke sorting system. Saving labor productivity, obviously improve production efficiency.

  3. Key issues

    International Nuclear Information System (INIS)

    Cook, N.G.W.

    1980-01-01

    Successful modeling of the thermo-mechanical and hydrochemical behavior of radioactive waste repositories in hard rock is possible in principle. Because such predictions lie outside the realm of experience, their adequacy depends entirely upon a thorough understanding of three fundamental questions: an understanding of the chemical and physical processess that determine the behavior of rock and all its complexities; accurate and realistic numerical models of the geologic media within which a repository may be built; and sufficient in-situ data covering the entire geologic region affected by, or effecting the behavior of a repository. At present sufficient is known to be able to identify most of those areas which require further attention. These areas extend all the way from a complete understanding of the chemical and physical processes determining the behavior of rock through to the exploration mapping and testing that must be done during the development of any potential repository. Many of the techniques, laboratory equipment, field instrumentation, and numerical methods needed to accomplish this do not exist at present. Therefore it is necessary to accept that a major investment in scientific research is required to generate this information over the next few years. The spectrum of scientific and engineering activities is wide extending from laboratory measurements through the development of numerical models to the measurement of data in-situ, but there is every prospect that sufficient can be done to resolve these key issues. However, to do so requires overt recognition of the many gaps which exist in our knowledge and abilities today, and of the need to bridge these gaps and of the significant costs involved in doing so

  4. Deficits of reach-to-grasp coordination following stroke: Comparison of instructed and natural movements.

    Science.gov (United States)

    Baak, Benjamin; Bock, Otmar; Dovern, Anna; Saliger, Jochen; Karbe, Hans; Weiss, Peter H

    2015-10-01

    The present work evaluates whether stroke-induced deficits of reach-to-grasp movements, established by typical laboratory paradigms, transfer unconditionally to more natural situations. Sixteen patients with a stroke to the motor-dominant left hemisphere and 16 age- and gender-matched healthy control subjects executed grasping movements with their left (ipsilesional, non-dominant) hand. All movements started in the same position, were aimed at the same object positioned in the same location, and were followed by forward displacement of that object along the same path. Twenty movements were performed as a repetitive, externally triggered task executed for their own sake (context L, as in typical laboratory tasks). Twenty movements were performed as part of a self-initiated action sequence aimed at winning a reward (context E, similar to many everyday situations). The kinematics and dynamics of the transport, grasp and manipulation component of each reach-to-grasp movement were quantified by 41 parameters. Analyses of variance yielded a significant effect of Context for 29 parameters, a significant effect of Group for 9 parameters (mostly related to the coupling of hand transport and grip aperture), and a significant interaction for 5 parameters (all related to the coupling of hand transport and grip aperture). The interaction reflected the fact that stroke patients' movement parameters were more abnormal in context E than in context L. Our data indicate that unilateral stroke degrades the grasp-transport coupling, and that stroke-related motor deficits may be more pronounced in a natural than in a laboratory context. Thus, for stroke patients, assessments and rehabilitation regimes should mainly use activities that are as natural as possible. Copyright © 2015 Elsevier Ltd. All rights reserved.

  5. Pantomime-grasping: Advance knowledge of haptic feedback availability supports an absolute visuo-haptic calibration

    Directory of Open Access Journals (Sweden)

    Shirin eDavarpanah Jazi

    2016-05-01

    Full Text Available An emerging issue in movement neurosciences is whether haptic feedback influences the nature of the information supporting a simulated grasping response (i.e., pantomime-grasping. In particular, recent work by our group contrasted pantomime-grasping responses performed with (i.e., PH+ trials and without (i.e., PH- trials terminal haptic feedback in separate blocks of trials. Results showed that PH- trials were mediated via relative visual information. In contrast, PH+ trials showed evidence of an absolute visuo-haptic calibration – a finding attributed to an error signal derived from a comparison between expected and actual haptic feedback (i.e., an internal forward model. The present study examined whether advanced knowledge of haptic feedback availability influences the aforementioned calibration process. To that end, PH- and PH+ trials were completed in separate blocks (i.e., the feedback schedule used in our group’s previous study and a block wherein PH- and PH+ trials were randomly interleaved on a trial-by-trial basis (i.e., random feedback schedule. In other words, the random feedback schedule precluded participants from predicting whether haptic feedback would be available at the movement goal location. We computed just-noticeable-difference (JND values to determine whether responses adhered to, or violated, the relative psychophysical principles of Weber’s law. Results for the blocked feedback schedule replicated our group’s previous work, whereas in the random feedback schedule PH- and PH+ trials were supported via relative visual information. Accordingly, we propose that a priori knowledge of haptic feedback is necessary to support an absolute visuo-haptic calibration. Moreover, our results demonstrate that the presence and expectancy of haptic feedback is an important consideration in contrasting the behavioral and neural properties of natural and stimulated (i.e., pantomime-grasping grasping.

  6. Differences between kinematic synergies and muscle synergies during two-digit grasping

    Directory of Open Access Journals (Sweden)

    Michele eTagliabue

    2015-03-01

    Full Text Available The large number of mechanical degrees of freedom of the hand is not fully exploited during actual movements such as grasping. Usually, angular movements in various joints tend to be coupled, and EMG activities in different hand muscles tend to be correlated. The occurrence of covariation in the former was termed kinematic synergies, in the latter muscle synergies. This study addresses two questions: (i Whether kinematic and muscle synergies can simultaneously accommodate for kinematic and kinetic constraints. (ii If so, whether there is an interrelation between kinematic and muscle synergies. We used a reach-grasp-and-pull paradigm and recorded the hand kinematics as well as 8 surface EMGs. Subjects had to either perform a precision grip or side grip and had to modify their grip force in order to displace an object against a low or high load. The analysis was subdivided into three epochs: reach, grasp-and-pull, and static hold. Principal component analysis (PCA, temporal or static was performed separately for all three epochs, in the kinematic and in the EMG domain. PCA revealed that (i Kinematic- and muscle-synergies can simultaneously accommodate kinematic (grip type and kinetic task constraints (load condition. (ii Upcoming grip and load conditions of the grasp are represented in kinematic- and muscle-synergies already during reach. Phase plane plots of the principal muscle-synergy against the principal kinematic synergy revealed (iii that the muscle-synergy is linked (correlated, and in phase advance to the kinematic synergy during reach and during grasp-and-pull. Furthermore (iv, pair-wise correlations of EMGs during hold suggest that muscle-synergies are (in part implemented by coactivation of muscles through common input. Together, these results suggest that kinematic synergies have (at least in part their origin not just in muscular activation, but in synergiestic muscle activation. In short: kinematic synergies may result from muscle

  7. Volitional and automatic control of the hand when reaching to grasp objects.

    Science.gov (United States)

    Chen, Zhongting; Saunders, Jeffrey Allen

    2018-02-26

    When picking up an object, we tend to grasp at contact points that allow a stable grip. Recent studies have demonstrated that appropriate grasp points can be selected during an ongoing movement in response to unexpected perturbations of the target object. In this study, we tested whether such online grip adjustments are automatic responses or can be controlled volitionally. Subjects performed virtual grasping movements toward target 2D shapes that sometimes changed shape or orientation during movement. Unlike in previous studies, the conditions and task requirements discouraged any online adjustments toward the perturbed shapes. In Experiment 1, target shapes were perturbed briefly (200 ms) during movement before reverting to the original shape, and subjects were instructed to ignore the transient perturbations. Despite subjects' intentions, we observed online adjustments of grip orientation that were toward the expected grip axis of the briefly presented shape. In Experiment 2, we added a stop-signal to the grasping task, with target perturbation as the stop cue. We again observed unnecessary online adjustments toward the grip axis of the perturbed shape, with similar latency. Furthermore, the grip adjustments continued after the forward motion of the hand had stopped, indicating that the automatic response to the perturbed target shape co-occurred with the volitional response to the perturbation onset. Our results provide evidence that automatic control mechanisms are used to guide the fingers to appropriate grasp points and suggest that these mechanisms are distinct from those involved with volitional control. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  8. Effects of accuracy constraints on reach-to-grasp movements in cerebellar patients.

    Science.gov (United States)

    Rand, M K; Shimansky, Y; Stelmach, G E; Bracha, V; Bloedel, J R

    2000-11-01

    Reach-to-grasp movements of patients with pathology restricted to the cerebellum were compared with those of normal controls. Two types of paradigms with different accuracy constraints were used to examine whether cerebellar impairment disrupts the stereotypic relationship between arm transport and grip aperture and whether the variability of this relationship is altered when greater accuracy is required. The movements were made to either a vertical dowel or to a cross bar of a small cross. All subjects were asked to reach for either target at a fast but comfortable speed, grasp the object between the index finger and thumb, and lift it a short distance off the table. In terms of the relationship between arm transport and grip aperture, the control subjects showed a high consistency in grip aperture and wrist velocity profiles from trial to trial for movements to both the dowel and the cross. The relationship between the maximum velocity of the wrist and the time at which grip aperture was maximal during the reach was highly consistent throughout the experiment. In contrast, the time of maximum grip aperture and maximum wrist velocity of the cerebellar patients was quite variable from trial to trial, and the relationship of these measurements also varied considerably. These abnormalities were present regardless of the accuracy requirement. In addition, the cerebellar patients required a significantly longer time to grasp and lift the objects than the control subjects. Furthermore, the patients exhibited a greater grip aperture during reach than the controls. These data indicate that the cerebellum contributes substantially to the coordination of movements required to perform reach-to-grasp movements. Specifically, the cerebellum is critical for executing this behavior with a consistent, well-timed relationship between the transport and grasp components. This contribution is apparent even when accuracy demands are minimal.

  9. Haptically Guided Grasping. fMRI Shows Right-Hemisphere Parietal Stimulus Encoding, and Bilateral Dorso-Ventral Parietal Gradients of Object- and Action-Related Processing during Grasp Execution.

    Science.gov (United States)

    Marangon, Mattia; Kubiak, Agnieszka; Króliczak, Gregory

    2015-01-01

    The neural bases of haptically-guided grasp planning and execution are largely unknown, especially for stimuli having no visual representations. Therefore, we used functional magnetic resonance imaging (fMRI) to monitor brain activity during haptic exploration of novel 3D complex objects, subsequent grasp planning, and the execution of the pre-planned grasps. Haptic object exploration, involving extraction of shape, orientation, and length of the to-be-grasped targets, was associated with the fronto-parietal, temporo-occipital, and insular cortex activity. Yet, only the anterior divisions of the posterior parietal cortex (PPC) of the right hemisphere were significantly more engaged in exploration of complex objects (vs. simple control disks). None of these regions were re-recruited during the planning phase. Even more surprisingly, the left-hemisphere intraparietal, temporal, and occipital areas that were significantly invoked for grasp planning did not show sensitivity to object features. Finally, grasp execution, involving the re-recruitment of the critical right-hemisphere PPC clusters, was also significantly associated with two kinds of bilateral parieto-frontal processes. The first represents transformations of grasp-relevant target features and is linked to the dorso-dorsal (lateral and medial) parieto-frontal networks. The second monitors grasp kinematics and belongs to the ventro-dorsal networks. Indeed, signal modulations associated with these distinct functions follow dorso-ventral gradients, with left aIPS showing significant sensitivity to both target features and the characteristics of the required grasp. Thus, our results from the haptic domain are consistent with the notion that the parietal processing for action guidance reflects primarily transformations from object-related to effector-related coding, and these mechanisms are rather independent of sensory input modality.

  10. Rethink! prototyping transdisciplinary concepts of prototyping

    CERN Document Server

    Nagy, Emilia; Stark, Rainer

    2016-01-01

    In this book, the authors describe the findings derived from interaction and cooperation between scientific actors employing diverse practices. They reflect on distinct prototyping concepts and examine the transformation of development culture in their fusion to hybrid approaches and solutions. The products of tomorrow are going to be multifunctional, interactive systems – and already are to some degree today. Collaboration across multiple disciplines is the only way to grasp their complexity in design concepts. This underscores the importance of reconsidering the prototyping process for the development of these systems, particularly in transdisciplinary research teams. “Rethinking Prototyping – new hybrid concepts for prototyping” was a transdisciplinary project that took up this challenge. The aim of this programmatic rethinking was to come up with a general concept of prototyping by combining innovative prototyping concepts, which had been researched and developed in three sub-projects: “Hybrid P...

  11. CONTROL OF APERTURE CLOSURE INITIATION DURING TRUNK-ASSISTED REACH-TO-GRASP MOVEMENTS

    Science.gov (United States)

    Rand, Miya K.; Van Gemmert, Arend W. A.; Hossain, Abul B.M.I.; Shimansky, Yury P.; Stelmach, George E.

    2012-01-01

    The present study investigated how the involvement and direction of trunk movement during reach-to-grasp movements affect the coordination between the transport and grasping components. Seated young adults made prehensile movements in which the involvement of the trunk was varied; the trunk was not involved, moved forward (flexion), or moved backward (extension) in the sagittal plane during the reach to the object. Each of the trunk movements was combined with an extension or flexion motion of the arm during the reach. Regarding the relation between the trunk and arm motion for arm transport, the onset of wrist motion relative to that of the trunk was delayed to a greater extent for the trunk extension than for the trunk flexion. The variability of the time period from the peak of wrist velocity to the peak of trunk velocity was also significantly greater for trunk extension compared to trunk flexion. These findings indicate that trunk flexion was better integrated into the control of wrist transport than trunk extension. In terms of the temporal relationship between wrist transport and grip aperture, the relation between the time of peak wrist velocity and the time of peak grip aperture did not change or became less steady across conditions. Therefore, the stability of temporal coordination between wrist transport and grip aperture was maintained despite the variation of the pattern of intersegmental coordination between the arm and the trunk during arm transport. The transport-aperture coordination was further assessed in terms of the control law according to which the initiation of aperture closure during the reach occurs when the hand crosses a hand-to-target distance threshold for grasp initiation that is a function of peak aperture, wrist velocity and acceleration, trunk velocity and acceleration, and trunk-to-target distance at the time of aperture closure initiation. The participants increased the hand-to-target distance threshold for grasp initiation in

  12. Control of aperture closure initiation during trunk-assisted reach-to-grasp movements.

    Science.gov (United States)

    Rand, Miya K; Van Gemmert, Arend W A; Hossain, Abul B M I; Shimansky, Yury P; Stelmach, George E

    2012-06-01

    The present study investigated how the involvement and direction of trunk movement during reach-to-grasp movements affect the coordination between the transport and grasping components. Seated young adults made prehensile movements in which the involvement of the trunk was varied; the trunk was not involved, moved forward (flexion), or moved backward (extension) in the sagittal plane during the reach to the object. Each of the trunk movements was combined with an extension or flexion motion of the arm during the reach. Regarding the relationship between the trunk and arm motion for arm transport, the onset of wrist motion relative to that of the trunk was delayed to a greater extent for the trunk extension than for the trunk flexion. The variability of the time period from the peak of wrist velocity to the peak of trunk velocity was also significantly greater for trunk extension compared to trunk flexion. These findings indicate that trunk flexion was better integrated into the control of wrist transport than trunk extension. In terms of the temporal relationship between wrist transport and grip aperture, the relationship between the time of peak wrist velocity and the time of peak grip aperture did not change or become less steady across conditions. Therefore, the stability of temporal coordination between wrist transport and grip aperture was maintained despite the variation of the pattern of intersegmental coordination between the arm and the trunk during arm transport. The transport-aperture coordination was further assessed in terms of the control law according to which the initiation of aperture closure during the reach occurs when the hand crosses a hand-to-target distance threshold for grasp initiation, which is a function of peak aperture, wrist velocity and acceleration, trunk velocity and acceleration, and trunk-to-target distance at the time of aperture closure initiation. The participants increased the hand-to-target distance threshold for grasp

  13. Comparison of grasping movements made by healthy subjects in a 3-dimensional immersive virtual versus physical environment.

    Science.gov (United States)

    Magdalon, Eliane C; Michaelsen, Stella M; Quevedo, Antonio A; Levin, Mindy F

    2011-09-01

    Virtual reality (VR) technology is being used with increasing frequency as a training medium for motor rehabilitation. However, before addressing training effectiveness in virtual environments (VEs), it is necessary to identify if movements made in such environments are kinematically similar to those made in physical environments (PEs) and the effect of provision of haptic feedback on these movement patterns. These questions are important since reach-to-grasp movements may be inaccurate when visual or haptic feedback is altered or absent. Our goal was to compare kinematics of reaching and grasping movements to three objects performed in an immersive three-dimensional (3D) VE with haptic feedback (cyberglove/grasp system) viewed through a head-mounted display to those made in an equivalent physical environment (PE). We also compared movements in PE made with and without wearing the cyberglove/grasp haptic feedback system. Ten healthy subjects (8 women, 62.1±8.8years) reached and grasped objects requiring 3 different grasp types (can, diameter 65.6mm, cylindrical grasp; screwdriver, diameter 31.6mm, power grasp; pen, diameter 7.5mm, precision grasp) in PE and visually similar virtual objects in VE. Temporal and spatial arm and trunk kinematics were analyzed. Movements were slower and grip apertures were wider when wearing the glove in both the PE and the VE compared to movements made in the PE without the glove. When wearing the glove, subjects used similar reaching trajectories in both environments, preserved the coordination between reaching and grasping and scaled grip aperture to object size for the larger object (cylindrical grasp). However, in VE compared to PE, movements were slower and had longer deceleration times, elbow extension was greater when reaching to the smallest object and apertures were wider for the power and precision grip tasks. Overall, the differences in spatial and temporal kinematics of movements between environments were greater than

  14. Gaze anchoring guides real but not pantomime reach-to-grasp: support for the action-perception theory.

    Science.gov (United States)

    Kuntz, Jessica R; Karl, Jenni M; Doan, Jon B; Whishaw, Ian Q

    2018-04-01

    Reach-to-grasp movements feature the integration of a reach directed by the extrinsic (location) features of a target and a grasp directed by the intrinsic (size, shape) features of a target. The action-perception theory suggests that integration and scaling of a reach-to-grasp movement, including its trajectory and the concurrent digit shaping, are features that depend upon online action pathways of the dorsal visuomotor stream. Scaling is much less accurate for a pantomime reach-to-grasp movement, a pretend reach with the target object absent. Thus, the action-perception theory proposes that pantomime movement is mediated by perceptual pathways of the ventral visuomotor stream. A distinguishing visual feature of a real reach-to-grasp movement is gaze anchoring, in which a participant visually fixates the target throughout the reach and disengages, often by blinking or looking away/averting the head, at about the time that the target is grasped. The present study examined whether gaze anchoring is associated with pantomime reaching. The eye and hand movements of participants were recorded as they reached for a ball of one of three sizes, located on a pedestal at arms' length, or pantomimed the same reach with the ball and pedestal absent. The kinematic measures for real reach-to-grasp movements were coupled to the location and size of the target, whereas the kinematic measures for pantomime reach-to-grasp, although grossly reflecting target features, were significantly altered. Gaze anchoring was also tightly coupled to the target for real reach-to-grasp movements, but there was no systematic focus for gaze, either in relation with the virtual target, the previous location of the target, or the participant's reaching hand, for pantomime reach-to-grasp. The presence of gaze anchoring during real vs. its absence in pantomime reach-to-grasp supports the action-perception theory that real, but not pantomime, reaches are online visuomotor actions and is discussed in

  15. Explicit knowledge about the availability of visual feedback affects grasping with the left but not the right hand.

    Science.gov (United States)

    Tang, Rixin; Whitwell, Robert L; Goodale, Melvyn A

    2014-01-01

    Previous research (Whitwell et al. in Exp Brain Res 188:603-611, 2008; Whitwell and Goodale in Exp Brain Res 194:619-629, 2009) has shown that trial history, but not anticipatory knowledge about the presence or absence of visual feedback on an upcoming trial, plays a vital role in determining how that feedback is exploited when grasping with the right hand. Nothing is known about how the non-dominant left hand behaves under the same feedback regimens. In present study, therefore, we compared peak grip aperture (PGA) for left- and right-hand grasps executed with and without visual feedback (i.e., closed- vs. open-loop conditions) in right-handed individuals under three different trial schedules: the feedback conditions were blocked separately, they were randomly interleaved, or they were alternated. When feedback conditions were blocked, the PGA was much larger for open-loop trials as compared to closed-loop trials, although this difference was more pronounced for right-hand grasps than left-hand grasps. Like Whitwell et al., we found that mixing open- and closed-loop trials together, compared to blocking them separately, homogenized the PGA for open- and closed-loop grasping in the right hand (i.e., the PGAs became smaller on open-loop trials and larger on closed-loop trials). In addition, the PGAs for right-hand grasps were entirely determined by trial history and not by knowledge of whether or not visual feedback would be available on an upcoming trial. In contrast to grasps made with the right hand, grasps made by the left hand were affected both by trial history and by anticipatory knowledge of the upcoming visual feedback condition. But these effects were observed only on closed-loop trials, i.e., the PGAs of grasps made with the left hand on closed-loop trials were smaller when participants could anticipate the availability of feedback on an upcoming trial (alternating trials) than when they could not (randomized trials). In contrast, grasps made with the

  16. Towards a standardized grasping and refuelling on-orbit servicing for geo spacecraft

    Science.gov (United States)

    Medina, Alberto; Tomassini, Angelo; Suatoni, Matteo; Avilés, Marcos; Solway, Nick; Coxhill, Ian; Paraskevas, Iosif S.; Rekleitis, Georgios; Papadopoulos, Evangelos; Krenn, Rainer; Brito, André; Sabbatinelli, Beatrice; Wollenhaupt, Birk; Vidal, Christian; Aziz, Sarmad; Visentin, Gianfranco

    2017-05-01

    Exploitation of space must benefit from the latest advances in robotics. On-orbit servicing is a clear candidate for the application of autonomous rendezvous and docking mechanisms. However, during the last three decades most of the trials took place combining extravehicular activities (EVAs) with telemanipulated robotic arms. The European Space Agency (ESA) considers that grasping and refuelling are promising near-mid-term capabilities that could be performed by servicing spacecraft. Minimal add-ons on spacecraft to enhance their serviceability may protect them for a changing future in which satellite servicing may become mainstream. ESA aims to conceive and promote standard refuelling provisions that can be installed in present and future European commercial geostationary orbit (GEO) satellite platforms and scientific spacecraft. For this purpose ESA has started the ASSIST activity addressing the analysis, design and validation of internal provisions (such as modifications to fuel, gas, electrical and data architecture to allow servicing) and external provisions (such as integrated berthing fixtures with peripheral electrical, gas, liquid connectors, leak check systems and corresponding optical and radio markers for cooperative rendezvous and docking). This refuelling approach is being agreed with European industry (OHB, Thales Alenia Space) and expected to be consolidated with European commercial operators as a first step to become an international standard; this approach is also being considered for on-orbit servicing spacecraft, such as the SpaceTug, by Airbus DS. This paper describes in detail the operational means, structure, geometry and accommodation of the system. Internal and external provisions will be designed with the minimum possible impact on the current architecture of GEO satellites without introducing additional risks in the development and commissioning of the satellite. End-effector and berthing fixtures are being designed in the range of few

  17. Integral Fast Reactor concept

    International Nuclear Information System (INIS)

    Till, C.E.; Chang, Y.I.

    1986-01-01

    The Integral Fast Reactor (IFR) is an innovative LMR concept, being developed at Argonne National Laboratory, that fully exploits the inherent properties of liquid metal cooling and metallic fuel to achieve breakthroughs in economics and inherent safety. This paper describes key features and potential advantages of the IFR concept, technology development status, fuel cycle economics potential, and future development path

  18. Integral Fast Reactor concept

    Energy Technology Data Exchange (ETDEWEB)

    Till, C.E.; Chang, Y.I.

    1986-01-01

    The Integral Fast Reactor (IFR) is an innovative LMR concept, being developed at Argonne National Laboratory, that fully exploits the inherent properties of liquid metal cooling and metallic fuel to achieve breakthroughs in economics and inherent safety. This paper describes key features and potential advantages of the IFR concept, technology development status, fuel cycle economics potential, and future development path.

  19. Integral fast reactor concept

    International Nuclear Information System (INIS)

    Chang, Y.I.; Marchaterre, J.F.; Sevy, R.H.

    1984-01-01

    Key features of the IFR consist of a pool-type plant arrangement, a metal fuel-based core design, and an integral fuel cycle with colocated fuel cycle facility. Both the basic concept and the technology base have been demonstrated through actual integral cycle operation in EBR-II. This paper discusses the inherent safety characteristics of the IFR concept

  20. Adding randomness controlling parameters in GRASP method applied in school timetabling problem

    Directory of Open Access Journals (Sweden)

    Renato Santos Pereira

    2017-09-01

    Full Text Available This paper studies the influence of randomness controlling parameters (RCP in first stage GRASP method applied in graph coloring problem, specifically school timetabling problems in a public high school. The algorithm (with the inclusion of RCP was based on critical variables identified through focus groups, whose weights can be adjusted by the user in order to meet the institutional needs. The results of the computational experiment, with 11-year-old data (66 observations processed at the same high school show that the inclusion of RCP leads to significantly lowering the distance between initial solutions and local minima. The acceptance and the use of the solutions found allow us to conclude that the modified GRASP, as has been constructed, can make a positive contribution to this timetabling problem of the school in question.

  1. Optimizing a Biobjective Production-Distribution Planning Problem Using a GRASP

    Directory of Open Access Journals (Sweden)

    Martha-Selene Casas-Ramírez

    2018-01-01

    Full Text Available This paper addresses a biobjective production-distribution planning problem. The problem is formulated as a mixed integer programming problem with two objectives. The objectives are to minimize the total costs and to balance the total workload of the supply chain, which consist of plants and depots, considering that it represents a company vertically integrated. In order to solve the model, we propose an adapted biobjective GRASP to obtain an approximation of the Pareto front. To evaluate the performance of the proposed algorithm, numerical experimentations are conducted over a set of instances used for similar problems. Results indicate that the proposed GRASP obtains a relatively small number of nondominated solutions for each tested instance in very short computational time. The approximated Pareto fronts are discontinuous and nonconvex. Moreover, the solutions clearly show the compromise between both objective functions.

  2. Bioinspired locomotion and grasping in water: the soft eight-arm OCTOPUS robot.

    Science.gov (United States)

    Cianchetti, M; Calisti, M; Margheri, L; Kuba, M; Laschi, C

    2015-05-13

    The octopus is an interesting model for the development of soft robotics, due to its high deformability, dexterity and rich behavioural repertoire. To investigate the principles of octopus dexterity, we designed an eight-arm soft robot and evaluated its performance with focused experiments. The OCTOPUS robot presented here is a completely soft robot, which integrates eight arms extending in radial direction and a central body which contains the main processing units. The front arms are mainly used for elongation and grasping, while the others are mainly used for locomotion. The robotic octopus works in water and its buoyancy is close to neutral. The experimental results show that the octopus-inspired robot can walk in water using the same strategy as the animal model, with good performance over different surfaces, including walking through physical constraints. It can grasp objects of different sizes and shapes, thanks to its soft arm materials and conical shape.

  3. Immediate movement history influences reach-to-grasp action selection in children and adults.

    Science.gov (United States)

    Kent, Samuel W; Wilson, Andrew D; Plumb, Mandy S; Williams, Justin H G; Mon-Williams, Mark

    2009-01-01

    Action selection is subject to many biases. Immediate movement history is one such bias seen in young infants. Is this bias strong enough to affect adult behavior? Adult participants reached and grasped a cylinder positioned to require either pronation or supination of the hand. Successive cylinder positions changed either randomly or systematically between trials. Random positioning led to optimized economy of movement. In contrast, systematic changes in position biased action selection toward previously selected actions at the expense of movement economy. Thus, one switches to a new movement only when the savings outweigh the costs of the switch. Immediate movement history had an even larger influence on children aged 7-15 years. This suggests that switching costs are greater in children, which is consistent with their reduced grasping experience. The presence of this effect in adults suggests that immediate movement history exerts a more widespread and pervasive influence on patterns of action selection than researchers had previously recognized.

  4. The GRASP project - a multidisciplinary study of hydrology and biogeochemistry in a periglacial catchment area

    Science.gov (United States)

    Johansson, Emma; Lindborg, Tobias

    2017-04-01

    The Arctic region is sensitive to global warming, and permafrost thaw and release of old carbon are examples of processes that may have a positive feedback effect to the global climate system. Quantification and assumptions on future change are often based on model predictions. Such models require cross-disciplinary data of high quality that often is lacking. Biogeochemical processes in the landscape are highly influenced by the hydrology, which in turn is intimately related to permafrost processes. Thus, a multidisciplinary approach is needed when collecting data and setting up field experiments aiming at increase the understanding of these processes. Here we summarize and present data collected in the GRASP, Greenland Analogue Surface Project. GRASP is a catchment-scale field study of the periglacial area in the Kangerlussuaq region, West Greenland, focusing on hydrological and biogeochemical processes in the landscape. The site investigations were initiated in 2010 and have since then resulted in three separate data sets published in ESSD (Earth system and Science Data) each one focusing on i) meteorological data and hydrology, ii) biogeochemistry and iii) geometries of sediments and the active layer. The three data-sets, which are freely available via the PANGAEA data base, enable conceptual and coupled numerical modeling of hydrological and biogeochemical processes. An important strength with the GRASP data is that all data is collected within the same, relatively small, catchment area. This implies that measurements are more easily linked to the right source area or process. Despite the small catchment area it includes the major units of the periglacial hydrological system; a lake, a talik, a supra- and subpermafrost aquifer and, consequently, biogeochemical processes in each of these units may be studied. The new data from GRASP is both used with the aim to increase the knowledge of present day periglacial hydrology and biogeochemistry but also in order to

  5. Retrieval of aerosol profiles combining sunphotometer and ceilometer measurements in GRASP code

    Science.gov (United States)

    Román, R.; Benavent-Oltra, J. A.; Casquero-Vera, J. A.; Lopatin, A.; Cazorla, A.; Lyamani, H.; Denjean, C.; Fuertes, D.; Pérez-Ramírez, D.; Torres, B.; Toledano, C.; Dubovik, O.; Cachorro, V. E.; de Frutos, A. M.; Olmo, F. J.; Alados-Arboledas, L.

    2018-05-01

    In this paper we present an approach for the profiling of aerosol microphysical and optical properties combining ceilometer and sun/sky photometer measurements in the GRASP code (General Retrieval of Aerosol and Surface Properties). For this objective, GRASP is used with sun/sky photometer measurements of aerosol optical depth (AOD) and sky radiances, both at four wavelengths and obtained from AErosol RObotic NETwork (AERONET), and ceilometer measurements of range corrected signal (RCS) at 1064 nm. A sensitivity study with synthetic data evidences the capability of the method to retrieve aerosol properties such as size distribution and profiles of volume concentration (VC), especially for coarse particles. Aerosol properties obtained by the mentioned method are compared with airborne in-situ measurements acquired during two flights over Granada (Spain) within the framework of ChArMEx/ADRIMED (Chemistry-Aerosol Mediterranean Experiment/Aerosol Direct Radiative Impact on the regional climate in the MEDiterranean region) 2013 campaign. The retrieved aerosol VC profiles agree well with the airborne measurements, showing a mean bias error (MBE) and a mean absolute bias error (MABE) of 0.3 μm3/cm3 (12%) and 5.8 μm3/cm3 (25%), respectively. The differences between retrieved VC and airborne in-situ measurements are within the uncertainty of GRASP retrievals. In addition, the retrieved VC at 2500 m a.s.l. is shown and compared with in-situ measurements obtained during summer 2016 at a high-atitude mountain station in the framework of the SLOPE I campaign (Sierra Nevada Lidar AerOsol Profiling Experiment). VC from GRASP presents high correlation (r = 0.91) with the in-situ measurements, but overestimates them, MBE and MABE being equal to 23% and 43%.

  6. The origins of thalamic inputs to grasp zones in frontal cortex of macaque monkeys

    OpenAIRE

    Gharbawie, Omar A.; Stepniewska, Iwona; Kaas, Jon H.

    2015-01-01

    The hand representation in primary motor cortex (M1) is instrumental to manual dexterity in primates. In Old World monkeys, rostral and caudal aspects of the hand representation are located in the precentral gyrus and the anterior bank of the central sulcus, respectively. We previously reported the organization of the cortico-cortical connections of the grasp zone in rostral M1. Here we describe the organization of thalamocortical connections that were labeled from the same tracer injections....

  7. Exploration of Hand Grasp Patterns Elicitable Through Non-Invasive Proximal Nerve Stimulation

    OpenAIRE

    Shin, Henry; Watkins, Zach; Hu, Xiaogang

    2017-01-01

    Various neurological conditions, such as stroke or spinal cord injury, result in an impaired control of the hand. One method of restoring this impairment is through functional electrical stimulation (FES). However, traditional FES techniques often lead to quick fatigue and unnatural ballistic movements. In this study, we sought to explore the capabilities of a non-invasive proximal nerve stimulation technique in eliciting various hand grasp patterns. The ulnar and median nerves proximal to th...

  8. Knowledge-Oriented Physics-Based Motion Planning for Grasping Under Uncertainty

    OpenAIRE

    Ud Din, Muhayy; Akbari, Aliakbar; Rosell Gratacòs, Jan

    2017-01-01

    Grasping an object in unstructured and uncertain environments is a challenging task, particularly when a collision-free trajectory does not exits. High-level knowledge and reasoning processes, as well as the allowing of interaction between objects, can enhance the planning efficiency in such environments. In this direction, this study proposes a knowledge-oriented physics-based motion planning approach for a hand-arm system that uses a high-level knowledge-based reasoning to partition the wor...

  9. Role of vision in aperture closure control during reach-to-grasp movements.

    Science.gov (United States)

    Rand, Miya K; Lemay, Martin; Squire, Linda M; Shimansky, Yury P; Stelmach, George E

    2007-08-01

    We have previously shown that the distance from the hand to the target at which finger closure is initiated during the reach (aperture closure distance) depends on the amplitude of peak aperture, as well as hand velocity and acceleration. This dependence suggests the existence of a control law according to which a decision to initiate finger closure during the reach is made when the hand distance to target crosses a threshold that is a function of the above movement-related parameters. The present study examined whether the control law is affected by manipulating the visibility of the hand and the target. Young adults made reach-to-grasp movements to a dowel under conditions in which the target or the hand or both were either visible or not visible. Reaching for and grasping a target when the hand and/or target were not visible significantly increased transport time and widened peak aperture. Aperture closure distance was significantly lengthened and wrist peak velocity was decreased only when the target was not visible. Further analysis showed that the control law was significantly different between the visibility-related conditions. When either the hand or target was not visible, the aperture closure distance systematically increased compared to its value for the same amplitude of peak aperture, hand velocity, and acceleration under full visibility. This implies an increase in the distance-related safety margin for grasping when the hand or target is not visible. It has been also found that the same control law can be applied to all conditions, if variables describing hand and target visibility were included in the control law model, as the parameters of the task-related environmental context, in addition to the above movement-related parameters. This suggests that that the CNS utilizes those variables for controlling grasp initiation based on a general control law.

  10. Connections of Grasping and Horizontal Hand Movements with Articulation in Czech Speakers

    Czech Academy of Sciences Publication Activity Database

    Tiainen, M.; Lukavský, Jiří; Tiippana, K.; Vainio, M.; Šimko, J.; Felisberti, F.; Vainio, L.

    2017-01-01

    Roč. 8, duben (2017), s. 1-10, č. článku 516. ISSN 1664-1078 Grant - others:AV ČR(CZ) StrategieAV21/14 Program:StrategieAV Institutional support: RVO:68081740 Keywords : articulation * motor actions * language * grasping * manual gestures * speech * manual actions Subject RIV: AN - Psychology OBOR OECD: Cognitive sciences Impact factor: 2.323, year: 2016

  11. Evaluation of Pressure Capacitive Sensors for Application in Grasping and Manipulation Analysis.

    Science.gov (United States)

    Pessia, Paola; Cordella, Francesca; Schena, Emiliano; Davalli, Angelo; Sacchetti, Rinaldo; Zollo, Loredana

    2017-12-08

    The analysis of the human grasping and manipulation capabilities is paramount for investigating human sensory-motor control and developing prosthetic and robotic hands resembling the human ones. A viable solution to perform this analysis is to develop instrumented objects measuring the interaction forces with the hand. In this context, the performance of the sensors embedded in the objects is crucial. This paper focuses on the experimental characterization of a class of capacitive pressure sensors suitable for biomechanical analysis. The analysis was performed in three loading conditions (Distributed load, 9 Tips load, and Wave-shaped load, thanks to three different inter-elements) via a traction/compression testing machine. Sensor assessment was also carried out under human- like grasping condition by placing a silicon material with the same properties of prosthetic cosmetic gloves in between the sensor and the inter-element in order to simulate the human skin. Data show that the input-output relationship of the analyzed, sensor is strongly influenced by both the loading condition (i.e., type of inter-element) and the grasping condition (with or without the silicon material). This needs to be taken into account to avoid significant measurement error. To go over this hurdle, the sensors have to be calibrated under each specific condition in order to apply suitable corrections to the sensor output and significantly improve the measurement accuracy.

  12. Reach–to-grasp movements in macaca fascicularis monkeys: the Isochrony Principle at work

    Directory of Open Access Journals (Sweden)

    Luisa eSartori

    2013-03-01

    Full Text Available Humans show a spontaneous tendency to increase the velocity of their movements depending on the linear extent of their trajectory in order to keep execution time approximately constant. Termed the isochrony principle, this compensatory mechanism refers to the observation that the velocity of voluntary movements increases proportionally with their linear extension. Although there is a wealth of psychophysical data regarding isochrony in humans, there is none regarding non-human primates. The present study attempts to fill that gap by investigating reach-to-grasp movement kinematics in free-ranging macaques. Video footage of monkeys grasping objects located at different distances was analyzed frame-by-frame using digitalization techniques. The amplitude of arm peak velocity was found to be correlated with the distance to be covered, and total movement duration remained invariant although target distances varied. Like in humans, the ‘isochrony principle’ seems to be operative as there is a gearing down/up of movement velocity that is proportional to the distance to be covered in order to allow for a relatively constant movement duration. Based on a centrally generated temporal template, this mode of motor programming could be functional in macaques given the high speed and great instability of posture and joint kinematics characterizing their actions. The data presented here take research in the field of comparative motor control a step forward as they are based on precise measurements of spontaneous grasping movements by animals living/acting in their natural environment.

  13. Reach-to-grasp movements in Macaca fascicularis monkeys: the Isochrony Principle at work

    Science.gov (United States)

    Sartori, Luisa; Camperio-Ciani, Andrea; Bulgheroni, Maria; Castiello, Umberto

    2013-01-01

    Humans show a spontaneous tendency to increase the velocity of their movements depending on the linear extent of their trajectory in order to keep execution time approximately constant. Termed the isochrony principle, this compensatory mechanism refers to the observation that the velocity of voluntary movements increases proportionally with their linear extension. Although there is a wealth of psychophysical data regarding isochrony in humans, there is none regarding non-human primates. The present study attempts to fill that gap by investigating reach-to-grasp movement kinematics in free-ranging macaques. Video footage of monkeys grasping objects located at different distances was analyzed frame-by-frame using digitalization techniques. The amplitude of arm peak velocity was found to be correlated with the distance to be covered, and total movement duration remained invariant although target distances varied. Like in humans, the “isochrony principle” seems to be operative as there is a gearing down/up of movement velocity that is proportional to the distance to be covered in order to allow for a relatively constant movement duration. Based on a centrally generated temporal template, this mode of motor programming could be functional in macaques given the high speed and great instability of posture and joint kinematics characterizing their actions. The data presented here take research in the field of comparative motor control a step forward as they are based on precise measurements of spontaneous grasping movements by animals living/acting in their natural environment. PMID:23658547

  14. Temporary Nerve Block at Selected Digits Revealed Hand Motor Deficits in Grasping Tasks

    Directory of Open Access Journals (Sweden)

    Aude Carteron

    2016-11-01

    Full Text Available Peripheral sensory feedback plays a crucial role in ensuring correct motor execution throughout hand grasp control. Previous studies utilized local anesthesia to deprive somatosensory feedback in the digits or hand, observations included sensorimotor deficits at both corticospinal and peripheral levels. However, the questions of how the disturbed and intact sensory input integrate and interact with each other to assist the motor program execution, and whether the motor coordination based on motor output variability between affected and non-affected elements (e.g., digits becomes interfered by the local sensory deficiency, have not been answered. The current study aims to investigate the effect of peripheral deafferentation through digital nerve blocks at selective digits on motor performance and motor coordination in grasp control. Our results suggested that the absence of somatosensory information induced motor deficits in hand grasp control, as evidenced by reduced maximal force production ability in both local and non-local digits, impairment of force and moment control during object lift and hold, and attenuated motor synergies in stabilizing task performance variables, namely the tangential force and moment of force. These findings implied that individual sensory input is shared across all the digits and the disturbed signal from local sensory channel(s has a more comprehensive impact on the process of the motor output execution in the sensorimotor integration process. Additionally, a feedback control mechanism with a sensation-based component resides in the formation process for the motor covariation structure.

  15. For your eyes only: Effect of confederate's eye level on reach-to-grasp action

    Directory of Open Access Journals (Sweden)

    Francois eQuesque

    2014-12-01

    Full Text Available Previous studies have shown that the spatio-temporal parameters of reach-to-grasp movement are influenced by the social context in which the motor action is performed. In particular, when interacting with a confederate, movements are slower, with longer initiation times and more ample trajectories, which has been interpreted as implicit communicative information emerging through voluntary movement to catch the partner’s attention and optimize cooperation (Quesque et al., 2013. Because gaze is a crucial component of social interactions, the present study evaluated the role of a confederate's eye level on the social modulation of trajectory curvature. An actor and a partner facing each other took part in a cooperative task consisting, for one of them, of grasping and moving a wooden dowel under time constraints. Before this Main action, the actor performed a Preparatory action, which consisted of placing the wooden dowel on a central marking. The partner's eye level was unnoticeably varied using an adjustable seat that matched or was higher than the actor’s seat. Our data confirmed the previous effects of social intention on motor responses. Furthermore, we observed an effect of the partner's eye level on the Preparatory action, leading the actors to exaggerate unconsciously the trajectory curvature in relation to their partner's eye level. No interaction was found between the actor's social intention and their partner's eye level. These results suggest that other bodies are implicitly taken into account when a reach-to-grasp movement is produced in a social context.

  16. Using an accelerometer for analyzing a reach-to-grasp movement after stroke

    Directory of Open Access Journals (Sweden)

    Stella Maris Michaelsen

    2013-12-01

    Full Text Available The purpose of this study was using an accelerometer to access the kinematics of reach-to-grasp movements in subjects with hemiparesis. Eight subjects (59.4 ± 6.9 years old with chronic hemiparesis (50.9 ± 25.8 months post-stroke participated in this study. Kinematic assessment was performed using a triaxial accelerometer (EMG Systems, Brazil attached to the subjects' forearm. Ten reach-to-grasp movements of grabbing a 500ml-size bottle were performed by the subjects with the paretic and the non-paretic upper limbs (ULs. The following space-temporal variables were calculated and used to compare the paretic and non-paretic ULs: movement time (MT, time to reach the peak velocity, absolute and relative (TPV and TPV%MT, relative deceleration duration (DEC%MT, time to peak acceleration (TPA and peak hand acceleration (PA. Movements were slower in the paretic UL with increased MT, TPA and DEC. The accelerometer allowed to identify of changes in reaching-to-grasp movements of subjects with hemiparesis. When complex systems are not available, accelerometers can be an alternative to measure UL movements.

  17. Grasping the intentions of others with one's own mirror neuron system.

    Directory of Open Access Journals (Sweden)

    Marco Iacoboni

    2005-03-01

    Full Text Available Understanding the intentions of others while watching their actions is a fundamental building block of social behavior. The neural and functional mechanisms underlying this ability are still poorly understood. To investigate these mechanisms we used functional magnetic resonance imaging. Twenty-three subjects watched three kinds of stimuli: grasping hand actions without a context, context only (scenes containing objects, and grasping hand actions performed in two different contexts. In the latter condition the context suggested the intention associated with the grasping action (either drinking or cleaning. Actions embedded in contexts, compared with the other two conditions, yielded a significant signal increase in the posterior part of the inferior frontal gyrus and the adjacent sector of the ventral premotor cortex where hand actions are represented. Thus, premotor mirror neuron areas-areas active during the execution and the observation of an action-previously thought to be involved only in action recognition are actually also involved in understanding the intentions of others. To ascribe an intention is to infer a forthcoming new goal, and this is an operation that the motor system does automatically.

  18. Grasp it loudly! Supporting actions with semantically congruent spoken action words.

    Directory of Open Access Journals (Sweden)

    Raphaël Fargier

    Full Text Available Evidence for cross-talk between motor and language brain structures has accumulated over the past several years. However, while a significant amount of research has focused on the interaction between language perception and action, little attention has been paid to the potential impact of language production on overt motor behaviour. The aim of the present study was to test whether verbalizing during a grasp-to-displace action would affect motor behaviour and, if so, whether this effect would depend on the semantic content of the pronounced word (Experiment I. Furthermore, we sought to test the stability of such effects in a different group of participants and investigate at which stage of the motor act language intervenes (Experiment II. For this, participants were asked to reach, grasp and displace an object while overtly pronouncing verbal descriptions of the action ("grasp" and "put down" or unrelated words (e.g. "butterfly" and "pigeon". Fine-grained analyses of several kinematic parameters such as velocity peaks revealed that when participants produced action-related words their movements became faster compared to conditions in which they did not verbalize or in which they produced words that were not related to the action. These effects likely result from the functional interaction between semantic retrieval of the words and the planning and programming of the action. Therefore, links between (action language and motor structures are significant to the point that language can refine overt motor behaviour.

  19. Learning to control a brain-machine interface for reaching and grasping by primates.

    Directory of Open Access Journals (Sweden)

    Jose M Carmena

    2003-11-01

    Full Text Available Reaching and grasping in primates depend on the coordination of neural activity in large frontoparietal ensembles. Here we demonstrate that primates can learn to reach and grasp virtual objects by controlling a robot arm through a closed-loop brain-machine interface (BMIc that uses multiple mathematical models to extract several motor parameters (i.e., hand position, velocity, gripping force, and the EMGs of multiple arm muscles from the electrical activity of frontoparietal neuronal ensembles. As single neurons typically contribute to the encoding of several motor parameters, we observed that high BMIc accuracy required recording from large neuronal ensembles. Continuous BMIc operation by monkeys led to significant improvements in both model predictions and behavioral performance. Using visual feedback, monkeys succeeded in producing robot reach-and-grasp movements even when their arms did not move. Learning to operate the BMIc was paralleled by functional reorganization in multiple cortical areas, suggesting that the dynamic properties of the BMIc were incorporated into motor and sensory cortical representations.

  20. Modelling and Simulation of a Manipulator with Stable Viscoelastic Grasping Incorporating Friction

    Directory of Open Access Journals (Sweden)

    A. Khurshid

    2016-12-01

    Full Text Available Design, dynamics and control of a humanoid robotic hand based on anthropological dimensions, with joint friction, is modelled, simulated and analysed in this paper by using computer aided design and multibody dynamic simulation. Combined joint friction model is incorporated in the joints. Experimental values of coefficient of friction of grease lubricated sliding contacts representative of manipulator joints are presented. Human fingers deform to the shape of the grasped object (enveloping grasp at the area of interaction. A mass-spring-damper model of the grasp is developed. The interaction of the viscoelastic gripper of the arm with objects is analysed by using Bond Graph modelling method. Simulations were conducted for several material parameters. These results of the simulation are then used to develop a prototype of the proposed gripper. Bond graph model is experimentally validated by using the prototype. The gripper is used to successfully transport soft and fragile objects. This paper provides information on optimisation of friction and its inclusion in both dynamic modelling and simulation to enhance mechanical efficiency.

  1. Changes in gross grasp strength and fine motor skills in adolescents with pediatric multiple sclerosis.

    Science.gov (United States)

    Squillace, Mary; Ray, Sharon; Milazzo, Maria

    2015-01-01

    This study examined the gross grasp strength and fine motor dexterity of adolescents, who are diagnosed with multiple sclerosis (MS). A total sample size of 72 participants between the ages of 13 to 17 was studied. Thirty six with a diagnosis of pediatric relapse remitting MS and 36 matched control participants were selected from various local youth groups. Data on hand strength and dexterity was collected using a dynamometer, nine hole peg board and Purdue pegboard on both groups. Utilizing ANCOVA to describe the differences across the two groups by diagnosis, controlling for age and gender, it was found that the MS group demonstrated significantly decreased dexterity when compared to age and gender matched controls. There was no significant difference in gross grasp strength by diagnostic group. This preliminary study showed that children with a diagnosis of pediatric MS may have differences in fine motor dexterity, but not gross grasp strength from their peers who do not have the diagnosis. Further study is indicated to examine this phenomenon.

  2. Resolving conflicts in task demands during balance recovery: does holding an object inhibit compensatory grasping?

    Science.gov (United States)

    Bateni, Hamid; Zecevic, Aleksandra; McIlroy, William E; Maki, Brian E

    2004-07-01

    The ability to reach and "grasp" (grip or touch) structures for support in reaction to instability is an important element of the postural repertoire. It is unclear, however, how the central nervous system (CNS) resolves the potential conflict between holding an object and the need to release the held object and grasp alternative support, particularly if the held object is perceived to be relevant to the task of stabilizing the body, e.g. an assistive device. This study examined whether compensatory grasping is inhibited when holding an object, and whether the influence differs when holding an assistive device (cane) versus a task-irrelevant object (top handle portion of a cane). We also investigated the influence of preloading the assistive device, to determine whether conflicting demands for arm-muscle activation (requiring disengagement of ongoing agonist or antagonist activity) would influence the inhibition of compensatory grasping. Unpredictable forward and backward platform translations were used to evoke the balancing reactions in 16 healthy young adults. A handrail was mounted to the right and foot motion was constrained by barriers, with the intent that successful balance recovery would (in large-perturbation trials) require subjects to release the held object and contact the rail with the right hand. Results showed that grasping reactions were commonly used to recover equilibrium when the hand was free (rail contact in 71% of large-perturbation trials). However, holding either the cane or canetop had a potent modulating effect: although early biceps activation was almost never inhibited completely (significant activity within 200 ms in 98% of trials), the average activation amplitude was attenuated by 30-64% and the average frequency of handrail contact was reduced by a factor of two or more. This reduced use of the rail occurred even though the consequence often involved falling against a safety harness or barriers. Handrail contact occurred least

  3. Control of aperture closure during reach-to-grasp movements in Parkinson's disease.

    Science.gov (United States)

    Rand, M K; Smiley-Oyen, A L; Shimansky, Y P; Bloedel, J R; Stelmach, G E

    2006-01-01

    This study examined whether the pattern of coordination between arm-reaching toward an object (hand transport) and the initiation of aperture closure for grasping is different between PD patients and healthy individuals, and whether that pattern is affected by the necessity to quickly adjust the reach-to-grasp movement in response to an unexpected shift of target location. Subjects reached for and grasped a vertical dowel, the location of which was indicated by illuminating one of the three dowels placed on a horizontal plane. In control conditions, target location was fixed during the trial. In perturbation conditions, target location was shifted instantaneously by switching the illumination to a different dowel during the reach. The hand distance from the target at which the subject initiated aperture closure (aperture closure distance) was similar for both the control and perturbation conditions within each group of subjects. However, that distance was significantly closer to the target in the PD group than in the control group. The timing of aperture closure initiation varied considerably across the trials in both groups of subjects. In contrast, aperture closure distance was relatively invariant, suggesting that aperture closure initiation was determined by spatial parameters of arm kinematics rather than temporal parameters. The linear regression analysis of aperture closure distance showed that the distance was highly predictable based on the following three parameters: the amplitude of maximum grip aperture, hand velocity, and hand acceleration. This result implies that a control law, the arguments of which include the above parameters, governs the initiation of aperture closure. Further analysis revealed that the control law was very similar between the subject groups under each condition as well as between the control and perturbation conditions for each group. Consequently, the shorter aperture closure distance observed in PD patients apparently is a

  4. Control of aperture closure during reach-to-grasp movements in parkinson’s disease

    Science.gov (United States)

    Rand, M. K.; Smiley-Oyen, A. L.; Shimansky, Y. P.; Bloedel, J. R.; Stelmach, G. E.

    2007-01-01

    This study examined whether the pattern of coordination between arm-reaching toward an object (hand transport) and the initiation of aperture closure for grasping is different between PD patients and healthy individuals, and whether that pattern is affected by the necessity to quickly adjust the reach-to-grasp movement in response to an unexpected shift of target location. Subjects reached for and grasped a vertical dowel, the location of which was indicated by illuminating one of the three dowels placed on a horizontal plane. In control conditions, target location was fixed during the trial. In perturbation conditions, target location was shifted instantaneously by switching the illumination to a different dowel during the reach. The hand distance from the target at which the subject initiated aperture closure (aperture closure distance) was similar for both the control and perturbation conditions within each group of subjects. However, that distance was significantly closer to the target in the PD group than in the control group. The timing of aperture closure initiation varied considerably across the trials in both groups of subjects. In contrast, aperture closure distance was relatively invariant, suggesting that aperture closure initiation was determined by spatial parameters of arm kinematics rather than temporal parameters. The linear regression analysis of aperture closure distance showed that the distance was highly predictable based on the following three parameters: the amplitude of maximum grip aperture, hand velocity, and hand acceleration. This result implies that a control law, the arguments of which include the above parameters, governs the initiation of aperture closure. Further analysis revealed that the control law was very similar between the subject groups under each condition as well as between the control and perturbation conditions for each group. Consequently, the shorter aperture closure distance observed in PD patients apparently is a

  5. Deep learning-based artificial vision for grasp classification in myoelectric hands

    Science.gov (United States)

    Ghazaei, Ghazal; Alameer, Ali; Degenaar, Patrick; Morgan, Graham; Nazarpour, Kianoush

    2017-06-01

    Objective. Computer vision-based assistive technology solutions can revolutionise the quality of care for people with sensorimotor disorders. The goal of this work was to enable trans-radial amputees to use a simple, yet efficient, computer vision system to grasp and move common household objects with a two-channel myoelectric prosthetic hand. Approach. We developed a deep learning-based artificial vision system to augment the grasp functionality of a commercial prosthesis. Our main conceptual novelty is that we classify objects with regards to the grasp pattern without explicitly identifying them or measuring their dimensions. A convolutional neural network (CNN) structure was trained with images of over 500 graspable objects. For each object, 72 images, at {{5}\\circ} intervals, were available. Objects were categorised into four grasp classes, namely: pinch, tripod, palmar wrist neutral and palmar wrist pronated. The CNN setting was first tuned and tested offline and then in realtime with objects or object views that were not included in the training set. Main results. The classification accuracy in the offline tests reached 85 % for the seen and 75 % for the novel objects; reflecting the generalisability of grasp classification. We then implemented the proposed framework in realtime on a standard laptop computer and achieved an overall score of 84 % in classifying a set of novel as well as seen but randomly-rotated objects. Finally, the system was tested with two trans-radial amputee volunteers controlling an i-limb UltraTM prosthetic hand and a motion controlTM prosthetic wrist; augmented with a webcam. After training, subjects successfully picked up and moved the target objects with an overall success of up to 88 % . In addition, we show that with training, subjects’ performance improved in terms of time required to accomplish a block of 24 trials despite a decreasing level of visual feedback. Significance. The proposed design constitutes a substantial

  6. Information about the weight of grasped objects from vision and internal models interacts within the primary motor cortex.

    Science.gov (United States)

    Loh, Morrison N; Kirsch, Louise; Rothwell, John C; Lemon, Roger N; Davare, Marco

    2010-05-19

    When grasping and lifting different objects, visual cues and previously acquired knowledge enable us to prepare the upcoming grasp by scaling the fingertip forces according to the actual weight of the object. However, when no visual information is available, the weight of the object has to be predicted based on information learned from previous grasps. Here, we investigated how changes in corticospinal excitability (CSE) and grip force scaling depend on the presence of visual cues and the weight of previously lifted objects. CSE was assessed by delivering transcranial magnetic stimulation (TMS) at different times before grasp of the object. In conditions in which visual information was not provided, the size of motor evoked potentials (MEP) was larger when the object lifted was preceded by a heavy relative to a light object. Interestingly, the previous lift also affected MEP amplitude when visual cues about object weight were available but only in the period immediately after object presentation (50 ms); this effect had already declined for TMS delivered 150 ms after presentation. In a second experiment, we demonstrated that these CSE changes are used by the motor system to scale grip force. This suggests that the corticospinal system stores a "sensorimotor memory" of the grasp of different objects and relies on this memory when no visual cues are present. Moreover, visual information about weight interacts with this stored representation and allows the corticospinal system to switch rapidly to a different model of predictive grasp control.

  7. An investigation of the neural circuits underlying reaching and reach-to-grasp movements: from planning to execution.

    Directory of Open Access Journals (Sweden)

    Chiara eBegliomini

    2014-09-01

    Full Text Available Experimental evidence suggests the existence of a sophisticated brain circuit specifically dedicated to reach-to-grasp planning and execution, both in human and non human primates (Castiello, 2005. Studies accomplished by means of neuroimaging techniques suggest the hypothesis of a dichotomy between a reach-to-grasp circuit, involving the intraparietal area (AIP, the dorsal and ventral premotor cortices (PMd and PMv - Castiello and Begliomini, 2008; Filimon, 2010 and a reaching circuit involving the medial intraparietal area (mIP and the Superior Parieto-Occipital Cortex (SPOC (Culham et al., 2006. However, the time course characterizing the involvement of these regions during the planning and execution of these two types of movements has yet to be delineated. A functional magnetic resonance imaging (fMRI study has been conducted, including reach-to grasp and reaching only movements, performed towards either a small or a large stimulus, and Finite Impulse Response model (FIR - Henson, 2003 was adopted to monitor activation patterns from stimulus onset for a time window of 10 seconds duration. Data analysis focused on brain regions belonging either to the reaching or to the grasping network, as suggested by Castiello & Begliomini (2008.Results suggest that reaching and grasping movements planning and execution might share a common brain network, providing further confirmation to the idea that the neural underpinnings of reaching and grasping may overlap in both spatial and temporal terms (Verhagen et al., 2013.

  8. On the road to a neuroprosthetic hand: a novel hand grasp orthosis based on functional electrical stimulation.

    Science.gov (United States)

    Leeb, Robert; Gubler, Miguel; Tavella, Michele; Miller, Heather; Del Millan, Jose R

    2010-01-01

    To patients who have lost the functionality of their hands as a result of a severe spinal cord injury or brain stroke, the development of new techniques for grasping is indispensable for reintegration and independency in daily life. Functional Electrical Stimulation (FES) of residual muscles can reproduce the most dominant grasping tasks and can be initialized by brain signals. However, due to the very complex hand anatomy and current limitations in FES-technology with surface electrodes, these grasp patterns cannot be smoothly executed. In this paper, we present an adaptable passive hand orthosis which is capable of producing natural and smooth movements when coupled with FES. It evenly synchronizes the grasping movements and applied forces on all fingers, allowing for naturalistic gestures and functional grasps of everyday objects. The orthosis is also equipped with a lock, which allows it to remain in the desired position without the need for long-term stimulation. Furthermore, we quantify improvements offered by the orthosis compare them with natural grasps on healthy subjects.

  9. Information about the weight of grasped objects from vision and from internal models interacts within the primary motor cortex

    Science.gov (United States)

    Loh, Morrison N; Kirsch, Louise; Rothwell, John C; Lemon, Roger N; Davare, Marco

    2010-01-01

    When grasping and lifting different objects, visual cues and previously acquired knowledge enable us to prepare the upcoming grasp by scaling the fingertip forces according to the actual weight of the object. However, when no visual information is available, the object’s weight has to be predicted based on information learned from previous grasps. Here, we investigated changes in corticospinal excitability (CSE) and grip force scaling depending on the presence of visual cues and the weight of previously lifted objects. CSE was assessed by delivering transcranial magnetic stimulation (TMS) at different times before grasp of the object. In conditions where visual information was not provided, the size of motor evoked potentials (MEP) was larger when the object lifted was preceded by a heavy relative to a light object. Interestingly, the previous lift also affected MEP amplitude when visual cues about object weight were available, but only in the period immediately after (50 ms) object presentation; this effect had already declined for TMS delivered 150 ms after presentation. In a second experiment, we demonstrated that these CSE changes are used by the motor system to scale grip force. This suggests that the corticospinal system stores a ‘sensorimotor memory’ of the grasp of different objects and relies on this memory when no visual cues are present. Moreover, visual information about weight interacts with this stored representation and allows the corticospinal system to switch rapidly to a different model of predictive grasp control. PMID:20484640

  10. Kierkegaard's concepts: Hypocrisy

    DEFF Research Database (Denmark)

    Fauth Hansen, Thomas Martin

    2014-01-01

    Kierkegaard’s Concepts is a comprehensive, multi-volume survey of the key concepts and categories that inform Kierkegaard’s writings. Each article is a substantial, original piece of scholarship, which discusses the etymology and lexical meaning of the relevant Danish term, traces the development...... of the concept over the course of the authorship, and explains how it functions in the wider context of Kierkegaard’s thought. Concepts have been selected on the basis of their importance for Kierkegaard’s contributions to philosophy, theology, the social sciences, literature and aesthetics, thereby making...... this volume an ideal reference work for students and scholars in a wide range of disciplines....

  11. A GRASP METAHEURISTIC FOR THE ORDERED CUTTING STOCK PROBLEM UN META-HEURÍSTICO GRASP PARA EL PROBLEMA DE STOCK DE CORTE ORDENADO

    Directory of Open Access Journals (Sweden)

    Rodrigo Rabello Golfeto

    2008-12-01

    Full Text Available This study presents a new mathematical model and a Greedy Randomized Adaptive Search Procedure (GRASP meta-heuristic to solve the ordered cutting stock problem. The ordered cutting stock problem was recently introduced in literature. It is appropriate to minimize the raw material used by industries that deal with reduced product inventories, such as industries that use the just-in-time basis for their production. In such cases, classic models for solving the cutting stock problem are useless. Results obtained from computational experiments for a set of random instances demonstrate that the proposed method can be applied to large industries that process cuts on their production lines and do not stock their products.Este estudio presenta un nuevo modelo matemático y un procedimiento meta-heurístico de búsqueda voraz adaptativa y aleatoria (GRASP, por sus siglas en inglés para resolver el problema de stock de corte ordenado. Éste problema ha sido introducido recientemente en la literatura. Es apropiado minimizar la materia prima usada por las industrias que manipulan inventarios reducidos de productos, tales como las industrias que usan la base justo a tiempo para su producción. En tales casos, los modelos clásicos para resolver el problema de stock de corte ordenado son inútiles. Los resultados obtenidos, mediante experimentos computacionales para un conjunto de ejemplos aleatorios, demuestran que el método propuesto puede ser aplicado a industrias grandes que procesan cortes en sus líneas de producción y no mantienen en stock sus productos.

  12. Key aspects congenital infection

    Directory of Open Access Journals (Sweden)

    Yu. V. Lobzin

    2014-01-01

    Full Text Available The key questions to solve the problem of congenital infection in the Russian Federation are: using in national practice over world accepted terminology adapted to the recommendations of the World Health Organization; representation of the modern concepts of an infectious process in the classification of congenital infections; scientific development and introducing in clinical practice the «standard case definitions», applied to different congenital infections; optimization of protocols and clinical guidelines for diagnosis, treatment and prevention of congenital infections; improvement a knowledge in the infectious disease for all  pecialists involved in the risk assessment of congenital infections, manage pregnancy and children. Based on our experience and analysis of publications, the authors suggest possible solutions.

  13. Elucidating Concepts in Drug Design through Taste with Natural and Artificial Sweeteners

    Science.gov (United States)

    Lipchock, James M.; Lipchock, Sarah V.

    2016-01-01

    Fundamental concepts in biochemistry important for drug design often lack connection to the macroscopic world and can be difficult for students to grasp, particularly those in introductory science courses at the high school and college level. Educational research has shown that multisensory teaching facilitates learning, but teaching at the high…

  14. Number Worlds: Visual and Experimental Access to Elementary Number Theory Concepts

    Science.gov (United States)

    Sinclair, Nathalie; Zazkis, Rina; Liljedahl, Peter

    2004-01-01

    Recent research demonstrates that many issues related to the structure of natural numbers and the relationship among numbers are not well grasped by students. In this article, we describe a computer-based learning environment called "Number Worlds" that was designed to support the exploration of elementary number theory concepts by…

  15. The Effects of Word-Learning Biases on Children's Concept of Angle

    Science.gov (United States)

    Gibson, Dominic J.; Congdon, Eliza L.; Levine, Susan C.

    2015-01-01

    Despite evidence that young children are sensitive to differences in angle measure, older students frequently struggle to grasp this important mathematical concept. When making judgments about the size of angles, children often rely on erroneous dimensions such as the length of the angles' sides. The present study tested the possibility that…

  16. Self-gated fetal cardiac MRI with tiny golden angle iGRASP: A feasibility study.

    Science.gov (United States)

    Haris, Kostas; Hedström, Erik; Bidhult, Sebastian; Testud, Frederik; Maglaveras, Nicos; Heiberg, Einar; Hansson, Stefan R; Arheden, Håkan; Aletras, Anthony H

    2017-07-01

    To develop and assess a technique for self-gated fetal cardiac cine magnetic resonance imaging (MRI) using tiny golden angle radial sampling combined with iGRASP (iterative Golden-angle RAdial Sparse Parallel) for accelerated acquisition based on parallel imaging and compressed sensing. Fetal cardiac data were acquired from five volunteers in gestational week 29-37 at 1.5T using tiny golden angles for eddy currents reduction. The acquired multicoil radial projections were input to a principal component analysis-based compression stage. The cardiac self-gating (CSG) signal for cardiac gating was extracted from the acquired radial projections and the iGRASP reconstruction procedure was applied. In all acquisitions, a total of 4000 radial spokes were acquired within a breath-hold of less than 15 seconds using a balanced steady-state free precession pulse sequence. The images were qualitatively compared by two independent observers (on a scale of 1-4) to a single midventricular cine image from metric optimized gating (MOG) and real-time acquisitions. For iGRASP and MOG images, good overall image quality (2.8 ± 0.4 and 2.6 ± 1.3, respectively, for observer 1; 3.6 ± 0.5 and 3.4 ± 0.9, respectively, for observer 2) and cardiac diagnostic quality (3.8 ± 0.4 and 3.4 ± 0.9, respectively, for observer 1; 3.6 ± 0.5 and 3.6 ± 0.9, respectively, for observer 2) were obtained, with visualized myocardial thickening over the cardiac cycle and well-defined myocardial borders to ventricular lumen and liver/lung tissue. For iGRASP, MOG, and real time, left ventricular lumen diameter (14.1 ± 2.2 mm, 14.2 ± 1.9 mm, 14.7 ± 1.1 mm, respectively) and wall thickness (2.7 ± 0.3 mm, 2.6 ± 0.3 mm, 3.0 ± 0.4, respectively) showed agreement and no statistically significant difference was found (all P > 0.05). Images with iGRASP tended to have higher overall image quality scores compared with MOG and particularly

  17. The anterior intraparietal sulcus mediates grasp execution, independent of requirement to update: new insights from transcranial magnetic stimulation.

    Science.gov (United States)

    Rice, Nichola J; Tunik, Eugene; Grafton, Scott T

    2006-08-02

    Although a role of the intraparietal sulcus (IPS) in grasping is becoming evident, the specific contribution of regions within the IPS remains undefined. In this vein, transcranial magnetic stimulation (TMS) was delivered to the anterior (aIPS), middle (mIPS), and caudal (cIPS) IPS in two tasks designed to dissociate the potential roles of the IPS in either grasp planning or execution (task 1) and its involvement in error detection or error correction (task 2). Determining the involvement of specific regions of the IPS in perceptual (planning and error detection) versus motor (execution and correction) components of grasping allowed us to assess the ecological validity of competing computational models attempting to simulate reach-to-grasp movements. In task 1, we demonstrate that, when no on-line adjustment is necessary, TMS to aIPS (but not mIPS or cIPS) disrupts grasping; this disruption is only elicited when TMS is applied during the execution (but not the planning) phase of the movement. Task 2 reveals that TMS to aIPS (but not mIPS or cIPS) disrupts grasping in the presence of a perturbation; this disruption is only elicited when TMS is applied during the error correction (but not error detection) phase of the movement. We propose that the specific contribution of the aIPS in grasping is in the on-line computation of a difference vector based on motor goal, efference copy, and sensory inputs. This computation is performed for both stable and perturbed motor goals.

  18. Quantum key distribution via quantum encryption

    CERN Document Server

    Yong Sheng Zhang; Guang Can Guo

    2001-01-01

    A quantum key distribution protocol based on quantum encryption is presented in this Brief Report. In this protocol, the previously shared Einstein-Podolsky-Rosen pairs act as the quantum key to encode and decode the classical cryptography key. The quantum key is reusable and the eavesdropper cannot elicit any information from the particle Alice sends to Bob. The concept of quantum encryption is also discussed. (21 refs).

  19. Real-time Pipeline for Object Modeling and Grasping Pose Selection via Superquadric Functions

    Directory of Open Access Journals (Sweden)

    Giulia Vezzani

    2017-11-01

    Full Text Available This work provides a novel real-time pipeline for modeling and grasping of unknown objects with a humanoid robot. Such a problem is of great interest for the robotic community, since conventional approaches fail when the shape, dimension, or pose of the objects are missing. Our approach reconstructs in real-time a model for the object under consideration and represents the robot hand both with proper and mathematically usable models, i.e., superquadric functions. The volume graspable by the hand is represented by an ellipsoid and is defined a priori, because the shape of the hand is known in advance. The superquadric representing the object is obtained in real-time from partial vision information instead, e.g., one stereo view of the object under consideration, and provides an approximated 3D full model. The optimization problem we formulate for the grasping pose computation is solved online by using the Ipopt software package and, thus, does not require off-line computation or learning. Even though our approach is for a generic humanoid robot, we developed a complete software architecture for executing this approach on the iCub humanoid robot. Together with that, we also provide a tutorial on how to use this framework. We believe that our work, together with the available code, is of a strong utility for the iCub community for three main reasons: object modeling and grasping are relevant problems for the robotic community, our code can be easily applied on every iCub, and the modular structure of our framework easily allows extensions and communications with external code.

  20. Getting a grip: different actions and visual guidance of the thumb and finger in precision grasping.

    Science.gov (United States)

    Melmoth, Dean R; Grant, Simon

    2012-10-01

    We manipulated the visual information available for grasping to examine what is visually guided when subjects get a precision grip on a common class of object (upright cylinders). In Experiment 1, objects (2 sizes) were placed at different eccentricities to vary the relative proximity to the participant's (n = 6) body of their thumb and finger contact positions in the final grip orientations, with vision available throughout or only for movement programming. Thumb trajectories were straighter and less variable than finger paths, and the thumb normally made initial contact with the objects at a relatively invariant landing site, but consistent thumb first-contacts were disrupted without visual guidance. Finger deviations were more affected by the object's properties and increased when vision was unavailable after movement onset. In Experiment 2, participants (n = 12) grasped 'glow-in-the-dark' objects wearing different luminous gloves in which the whole hand was visible or the thumb or the index finger was selectively occluded. Grip closure times were prolonged and thumb first-contacts disrupted when subjects could not see their thumb, whereas occluding the finger resulted in wider grips at contact because this digit remained distant from the object. Results were together consistent with visual feedback guiding the thumb in the period just prior to contacting the object, with the finger more involved in opening the grip and avoiding collision with the opposite contact surface. As people can overtly fixate only one object contact point at a time, we suggest that selecting one digit for online guidance represents an optimal strategy for initial grip placement. Other grasping tasks, in which the finger appears to be used for this purpose, are discussed.

  1. Force-independent distribution of correlated neural inputs to hand muscles during three-digit grasping.

    Science.gov (United States)

    Poston, Brach; Danna-Dos Santos, Alessander; Jesunathadas, Mark; Hamm, Thomas M; Santello, Marco

    2010-08-01

    The ability to modulate digit forces during grasping relies on the coordination of multiple hand muscles. Because many muscles innervate each digit, the CNS can potentially choose from a large number of muscle coordination patterns to generate a given digit force. Studies of single-digit force production tasks have revealed that the electromyographic (EMG) activity scales uniformly across all muscles as a function of digit force. However, the extent to which this finding applies to the coordination of forces across multiple digits is unknown. We addressed this question by asking subjects (n = 8) to exert isometric forces using a three-digit grip (thumb, index, and middle fingers) that allowed for the quantification of hand muscle coordination within and across digits as a function of grasp force (5, 20, 40, 60, and 80% maximal voluntary force). We recorded EMG from 12 muscles (6 extrinsic and 6 intrinsic) of the three digits. Hand muscle coordination patterns were quantified in the amplitude and frequency domains (EMG-EMG coherence). EMG amplitude scaled uniformly across all hand muscles as a function of grasp force (muscle x force interaction: P = 0.997; cosines of angle between muscle activation pattern vector pairs: 0.897-0.997). Similarly, EMG-EMG coherence was not significantly affected by force (P = 0.324). However, coherence was stronger across extrinsic than that across intrinsic muscle pairs (P = 0.0039). These findings indicate that the distribution of neural drive to multiple hand muscles is force independent and may reflect the anatomical properties or functional roles of hand muscle groups.

  2. Periodic modulation of motor-unit activity in extrinsic hand muscles during multidigit grasping.

    Science.gov (United States)

    Johnston, Jamie A; Winges, Sara A; Santello, Marco

    2005-07-01

    We recently examined the extent to which motor units of digit flexor muscles receive common input during multidigit grasping. This task elicited moderate to strong motor-unit synchrony (common input strength, CIS) across muscles (flexor digitorum profundus, FDP, and flexor pollicis longus, FPL) and across FDP muscle compartments, although the strength of this common input was not uniform across digit pairs. To further characterize the neural mechanisms underlying the control of multidigit grasping, we analyzed the relationship between firing of single motor units from these hand muscles in the frequency domain by computing coherence. We report three primary findings. First, in contrast to what has been reported in intrinsic hand muscles, motor units belonging to different muscles and muscle compartments of extrinsic digit flexors exhibited significant coherence in the 0- to 5- and 5- to 10-Hz frequency ranges and much weaker coherence in the higher 10-20 Hz range (maximum 0.0025 and 0.0008, respectively, pooled across all FDP compartment pairs). Second, the strength and incidence of coherence differed considerably across digit pairs. Third, contrary to what has been reported in the literature, across-muscle coherence can be stronger and more prevalent than within-muscle coherence, as FPL-FDP2 (thumb-index digit pair) exhibited the strongest and most prevalent coherence in our data (0.010 and 43% at 3 Hz, respectively). The heterogeneous organization of common input to these muscles and muscle compartments is discussed in relation to the functional role of individual digit pairs in the coordination of multiple digit forces in grasping.

  3. Case: Making students grasp the concept of differential equations in a broader and more flexible way by using computers

    DEFF Research Database (Denmark)

    Andresen, Mette

    2003-01-01

    their abilities in this area. Organizing mathematical objects by building structures, as well as by handling the interaction between the component parts and the structures in full, is one activity in learning mathematics at all levels in school. I have concentrated on setting up and solving differential equations......, because this area offers a suitable structure complexity at various levels. Furthermore, one point of interest for me is to find out how to use CAS (Computer Algebraic Systems) constructively in this context. I feel that research in this area could prove valuable, provided that its outcome in the form...... through specific directions for subsequently implementing in teaching practice. Abstract: Teaching mathematics for more than 12 years, mainly at upper secondary school level, I have often wondered why the ability to handle structures seemingly is insufficiently developed in many students. It causes them...

  4. Age-related loss of early grasp affordance when viewing a safety handle

    OpenAIRE

    McDannald, Doug

    2018-01-01

    Age-related loss of early grasp affordance when viewing a safety handle Author: D.W. McDannald1, , M. Mansour2, G. Rydalch3, D.A.E. Bolton1 Mere observation of objects in our surroundings can potentiate movement, a fact reflected by visually-primed activation of motor cortical networks. This mechanism holds potential value for reactive balance control where recovery actions of the arms or legs must be targeted to a new support base to avoid a fall. The present study was conducted to test if t...

  5. Anticipatory modulation of digit placement for grasp control is affected by Parkinson's disease.

    Directory of Open Access Journals (Sweden)

    Jamie R Lukos

    2010-02-01

    Full Text Available Successful object manipulation relies on the ability to form and retrieve sensorimotor memories of digit forces and positions used in previous object lifts. Past studies of patients affected by Parkinson's disease (PD have revealed that the basal ganglia play a crucial role in the acquisition and/or retrieval of sensorimotor memories for grasp control. Whereas it is known that PD impairs anticipatory control of digit forces during grasp, learning deficits associated with the planning of digit placement have yet to be explored. This question is motivated by recent work in healthy subjects revealing that anticipatory control of digit placement plays a crucial role for successful manipulation.We asked ten PD patients off medication and ten age-matched controls to reach, grasp and lift an object whose center of mass (CM was on the left, right or center. The only task requirement was to minimize object roll during lift. The CM remained the same across consecutive trials (blocked condition or was altered from trial to trial (random condition. We hypothesized that impairment of the basal ganglia-thalamo-cortical circuits in PD patients would reduce their ability to anticipate digit placement appropriate to the CM location. Consequently, we predicted that PD patients would exhibit similar digit placement in the blocked vs. random conditions and produce larger peak object rolls than that of control subjects. In the blocked condition, PD patients exhibited significantly weaker modulation of fingertip contact points to CM location and larger object roll than controls (p<0.05 and p<0.01, respectively. Nevertheless, both controls and PD patients minimized object roll more in the blocked than in the random condition (p<0.01.Our findings indicate that, even though PD patients may have a residual ability of anticipatory control of digit contact points and forces, they fail to implement a motor plan with the same degree of effectiveness as controls. We conclude

  6. Adaptation of reach-to-grasp movement in response to force perturbations.

    Science.gov (United States)

    Rand, M K; Shimansky, Y; Stelmach, G E; Bloedel, J R

    2004-01-01

    This study examined how reach-to-grasp movements are modified during adaptation to external force perturbations applied on the arm during reach. Specifically, we examined whether the organization of these movements was dependent upon the condition under which the perturbation was applied. In response to an auditory signal, all subjects were asked to reach for a vertical dowel, grasp it between the index finger and thumb, and lift it a short distance off the table. The subjects were instructed to do the task as fast as possible. The perturbation was an elastic load acting on the wrist at an angle of 105 deg lateral to the reaching direction. The condition was modified by changing the predictability with which the perturbation was applied in a given trial. After recording unperturbed control trials, perturbations were applied first on successive trials (predictable perturbations) and then were applied randomly (unpredictable perturbations). In the early predictable perturbation trials, reach path length became longer and reaching duration increased. As more predictable perturbations were applied, the reach path length gradually decreased and became similar to that of control trials. Reaching duration also decreased gradually as the subjects adapted by exerting force against the perturbation. In addition, the amplitude of peak grip aperture during arm transport initially increased in response to repeated perturbations. During the course of learning, it reached its maximum and thereafter slightly decreased. However, it did not return to the normal level. The subjects also adapted to the unpredictable perturbations through changes in both arm transport and grasping components, indicating that they can compensate even when the occurrence of the perturbation cannot be predicted during the inter-trial interval. Throughout random perturbation trials, large grip aperture values were observed, suggesting that a conservative aperture level is set regardless of whether the

  7. A continuous GRASP to determine the relationship between drugs and adverse reactions

    International Nuclear Information System (INIS)

    Hirsch, Michael J.; Meneses, Claudio N.; Pardalos, Panos M.; Ragle, Michelle; Resende, Mauricio G. C.

    2007-01-01

    Adverse drag reactions (ADRs) are estimated to be one of the leading causes of death. Many national and international agencies have set up databases of ADR reports for the express purpose of determining the relationship between drugs and adverse reactions that they cause. We formulate the drug-reaction relationship problem as a continuous optimization problem and utilize C-GRASP, a new continuous global optimization heuristic, to approximately determine the relationship between drugs and adverse reactions. Our approach is compared against others in the literature and is shown to find better solutions

  8. A GRASP model in network design for two-stage supply chain

    Directory of Open Access Journals (Sweden)

    Hassan Javanshir

    2011-04-01

    Full Text Available We consider a capacitated facility location problem (CFLP which contains a production facility and distribution centers (DCs supplying retailers' demand. The primary purpose is to locate distribution centres in the network and the objective is the minimization of the sum of fixed facility location, pipeline inventory, safety stock and lost sales. We use Greedy randomized adaptive search procedures (GRASP to solve the model. The preliminary results indicate that the proposed method of this paper could provide competitive results in reasonable amount time.

  9. Booklet for sub-national stakeholders heading towards the COP 21. Agricultural and forestry focus. Key concepts on the impacts of climate change, climate policies and economic tools: insight from French territories

    International Nuclear Information System (INIS)

    Depoues, Vivian; Leseur, Alexia; Bordier, Cecile; Foucherot, Claudine; Lacan, Lea; Planton, Serge; Blanchard, Michele; Lemonsu, Aude; Martin, Eric; Masson, Valery; Soubeyroux, Jean-Michel; Ouzeau, Gaelle; Dandin, Philippe; Pigeon, Gregoire; Duvernoy, Jerome; Mondon, Sylvain; Bodiguel, Aude; Gouthiere, Laurence; Martin-Phipps, Cecile; Archambault, Sabrina; Joubert, Marion; Madariaga, Nicole; Coste, Marie-Alexandra; Viguie, Vincent; Avner, Paolo; Cassen, Christophe; Guivarch, Celine; Salagnac, Jean-Luc; Carrega, Marie; Menager, Yann

    2015-11-01

    This report, released in the year of the Paris Climate 2015 summit (COP21), reviews concepts vital for understanding and acting to address climate change at a regional level. Based on the experience of French territories it presents 37 fact-sheets aimed at local players, providing concise and informative access to the most up-to-date knowledge. It also offers feedback on the impacts of climate change, climate policies at a global, European and French level, and economic tools supporting climate change mitigation and adaptation

  10. Repeatability of grasp recognition for robotic hand prosthesis control based on sEMG data.

    Science.gov (United States)

    Palermo, Francesca; Cognolato, Matteo; Gijsberts, Arjan; Muller, Henning; Caputo, Barbara; Atzori, Manfredo

    2017-07-01

    Control methods based on sEMG obtained promising results for hand prosthetics. Control system robustness is still often inadequate and does not allow the amputees to perform a large number of movements useful for everyday life. Only few studies analyzed the repeatability of sEMG classification of hand grasps. The main goals of this paper are to explore repeatability in sEMG data and to release a repeatability database with the recorded experiments. The data are recorded from 10 intact subjects repeating 7 grasps 12 times, twice a day for 5 days. The data are publicly available on the Ninapro web page. The analysis for the repeatability is based on the comparison of movement classification accuracy in several data acquisitions and for different subjects. The analysis is performed using mean absolute value and waveform length features and a Random Forest classifier. The accuracy obtained by training and testing on acquisitions at different times is on average 27.03% lower than training and testing on the same acquisition. The results obtained by training and testing on different acquisitions suggest that previous acquisitions can be used to train the classification algorithms. The inter-subject variability is remarkable, suggesting that specific characteristics of the subjects can affect repeatibility and sEMG classification accuracy. In conclusion, the results of this paper can contribute to develop more robust control systems for hand prostheses, while the presented data allows researchers to test repeatability in further analyses.

  11. Detumbling control for kinematically redundant space manipulator post-grasping a rotational satellite

    Science.gov (United States)

    Wang, Mingming; Luo, Jianjun; Yuan, Jianping; Walter, Ulrich

    2017-12-01

    The objective of this paper is to establish a detumbling strategy and a coordination control scheme for a kinematically redundant space manipulator post-grasping a rotational satellite. First, the dynamics of the kinematically redundant space robot after grasping the target is presented, which lays the foundation for the coordination controller design. Subsequently, optimal detumbling and motion planning strategy for the post-capture phase is proposed based on the quartic Bézier curves and adaptive differential evolution (DE) algorithm subject to the specific constraints. Both detumbling time and control torques are taken into account for the generation of the optimal detumbling strategy. Furthermore, a coordination control scheme is presented to track the designed reference path while regulating the attitude of the chaser to a desired value, which successfully dumps the initial angular velocity of the rotational satellite and controls the base attitude synchronously. Simulation results are presented for detumbling a target with rotational motion using a 7 degree-of-freedom (DOF) redundant space manipulator, which demonstrates the effectiveness of the proposed method.

  12. Grasp specific and user friendly interface design for myoelectric hand prostheses.

    Science.gov (United States)

    Mohammadi, Alireza; Lavranos, Jim; Howe, Rob; Choong, Peter; Oetomo, Denny

    2017-07-01

    This paper presents the design and characterisation of a hand prosthesis and its user interface, focusing on performing the most commonly used grasps in activities of daily living (ADLs). Since the operation of a multi-articulated powered hand prosthesis is difficult to learn and master, there is a significant rate of abandonment by amputees in preference for simpler devices. In choosing so, amputees chose to live with fewer features in their prosthesis that would more reliably perform the basic operations. In this paper, we look simultaneously at a hand prosthesis design method that aims for a small number of grasps, a low complexity user interface and an alternative method to the current use of EMG as a preshape selection method through the use of a simple button; to enable amputees to get to and execute the intended hand movements intuitively, quickly and reliably. An experiment is reported at the end of the paper comparing the speed and accuracy with which able-bodied naive subjects are able to select the intended preshapes through the use of a simplified EMG method and a simple button. It is shown that the button was significantly superior in the speed of successful task completion and marginally superior in accuracy (success of first attempt).

  13. Selective interference of grasp and space representations with number magnitude and serial order processing.

    Science.gov (United States)

    van Dijck, Jean-Philippe; Fias, Wim; Andres, Michael

    2015-10-01

    It has been proposed that the metrics of space, time and other magnitudes relevant for action are coupled through a generalized magnitude system that also contribute to number representation. Several studies capitalized on stimulus-response compatibility effects to show that numbers map onto left-right representations and grasp representations as a function of their magnitude. However, the tasks typically used do not allow disentangling magnitude from serial order processing. Here, we devised a working memory (WM) task where participants had to remember random sequences of numbers and perform a precision/whole-hand grip (Experiment 1) or a uni-manual left/right button press (Experiment 2) in response to numbers presented during the retention interval. This task does allow differentiating the interference of number magnitude and serial order with each set of responses. Experiment 1 showed that precision grips were initiated faster than whole-hand grips in response to small numbers, irrespective of their serial position in WM. In contrast, Experiment 2 revealed an advantage of right over left button presses as serial position increased, without any influence of number magnitude. These findings demonstrate that grasping and left-right movements overlap with distinct dimensions of number processing. These findings are discussed in the light of different theories explaining the interactions between numbers, space and action.

  14. Classification of Hand Grasp Kinetics and Types Using Movement-Related Cortical Potentials and EEG Rhythms

    Directory of Open Access Journals (Sweden)

    Mads Jochumsen

    2017-01-01

    Full Text Available Detection of single-trial movement intentions from EEG is paramount for brain-computer interfacing in neurorehabilitation. These movement intentions contain task-related information and if this is decoded, the neurorehabilitation could potentially be optimized. The aim of this study was to classify single-trial movement intentions associated with two levels of force and speed and three different grasp types using EEG rhythms and components of the movement-related cortical potential (MRCP as features. The feature importance was used to estimate encoding of discriminative information. Two data sets were used. 29 healthy subjects executed and imagined different hand movements, while EEG was recorded over the contralateral sensorimotor cortex. The following features were extracted: delta, theta, mu/alpha, beta, and gamma rhythms, readiness potential, negative slope, and motor potential of the MRCP. Sequential forward selection was performed, and classification was performed using linear discriminant analysis and support vector machines. Limited classification accuracies were obtained from the EEG rhythms and MRCP-components: 0.48±0.05 (grasp types, 0.41±0.07 (kinetic profiles, motor execution, and 0.39±0.08 (kinetic profiles, motor imagination. Delta activity contributed the most but all features provided discriminative information. These findings suggest that information from the entire EEG spectrum is needed to discriminate between task-related parameters from single-trial movement intentions.

  15. Recognition of grasp types through principal components of DWT based EMG features.

    Science.gov (United States)

    Kakoty, Nayan M; Hazarika, Shyamanta M

    2011-01-01

    With the advancement in machine learning and signal processing techniques, electromyogram (EMG) signals have increasingly gained importance in man-machine interaction. Multifingered hand prostheses using surface EMG for control has appeared in the market. However, EMG based control is still rudimentary, being limited to a few hand postures based on higher number of EMG channels. Moreover, control is non-intuitive, in the sense that the user is required to learn to associate muscle remnants actions to unrelated posture of the prosthesis. Herein lies the promise of a low channel EMG based grasp classification architecture for development of an embedded intelligent prosthetic controller. This paper reports classification of six grasp types used during 70% of daily living activities based on two channel forearm EMG. A feature vector through principal component analysis of discrete wavelet transform coefficients based features of the EMG signal is derived. Classification is through radial basis function kernel based support vector machine following preprocessing and maximum voluntary contraction normalization of EMG signals. 10-fold cross validation is done. We have achieved an average recognition rate of 97.5%. © 2011 IEEE

  16. Anticipatory planning and control of grasp positions and forces for dexterous two-digit manipulation.

    Science.gov (United States)

    Fu, Qiushi; Zhang, Wei; Santello, Marco

    2010-07-07

    Dexterous object manipulation requires anticipatory control of digit positions and forces. Despite extensive studies on sensorimotor learning of digit forces, how humans learn to coordinate digit positions and forces has never been addressed. Furthermore, the functional role of anticipatory modulation of digit placement to object properties remains to be investigated. We addressed these questions by asking human subjects (12 females, 12 males) to grasp and lift an inverted T-shaped object using precision grip at constrained or self-chosen locations. The task requirement was to minimize object roll during lift. When digit position was not constrained, subjects could have implemented many equally valid digit position-force coordination patterns. However, choice of digit placement might also have resulted in large trial-to-trial variability of digit position, hence challenging the extent to which the CNS could have relied on sensorimotor memories for anticipatory control of digit forces. We hypothesized that subjects would modulate digit placement for optimal force distribution and digit forces as a function of variable digit positions. All subjects learned to minimize object roll within the first three trials, and the unconstrained device was associated with significantly smaller grip forces but larger variability of digit positions. Importantly, however, digit load force modulation compensated for position variability, thus ensuring consistent object roll minimization on each trial. This indicates that subjects learned object manipulation by integrating sensorimotor memories with sensory feedback about digit positions. These results are discussed in the context of motor equivalence and sensorimotor integration of grasp kinematics and kinetics.

  17. A multi-pad electrode based functional electrical stimulation system for restoration of grasp

    Directory of Open Access Journals (Sweden)

    Malešević Nebojša M

    2012-09-01

    Full Text Available Abstract Background Functional electrical stimulation (FES applied via transcutaneous electrodes is a common rehabilitation technique for assisting grasp in patients with central nervous system lesions. To improve the stimulation effectiveness of conventional FES, we introduce multi-pad electrodes and a new stimulation paradigm. Methods The new FES system comprises an electrode composed of small pads that can be activated individually. This electrode allows the targeting of motoneurons that activate synergistic muscles and produce a functional movement. The new stimulation paradigm allows asynchronous activation of motoneurons and provides controlled spatial distribution of the electrical charge that is delivered to the motoneurons. We developed an automated technique for the determination of the preferred electrode based on a cost function that considers the required movement of the fingers and the stabilization of the wrist joint. The data used within the cost function come from a sensorized garment that is easy to implement and does not require calibration. The design of the system also includes the possibility for fine-tuning and adaptation with a manually controllable interface. Results The device was tested on three stroke patients. The results show that the multi-pad electrodes provide the desired level of selectivity and can be used for generating a functional grasp. The results also show that the procedure, when performed on a specific user, results in the preferred electrode configuration characteristics for that patient. The findings from this study are of importance for the application of transcutaneous stimulation in the clinical and home environments.

  18. Concepts of formal concept analysis

    Science.gov (United States)

    Žáček, Martin; Homola, Dan; Miarka, Rostislav

    2017-07-01

    The aim of this article is apply of Formal Concept Analysis on concept of world. Formal concept analysis (FCA) as a methodology of data analysis, information management and knowledge representation has potential to be applied to a verity of linguistic problems. FCA is mathematical theory for concepts and concept hierarchies that reflects an understanding of concept. Formal concept analysis explicitly formalizes extension and intension of a concept, their mutual relationships. A distinguishing feature of FCA is an inherent integration of three components of conceptual processing of data and knowledge, namely, the discovery and reasoning with concepts in data, discovery and reasoning with dependencies in data, and visualization of data, concepts, and dependencies with folding/unfolding capabilities.

  19. GRASP para o PQA: um limite de aceitação para soluções iniciais

    Directory of Open Access Journals (Sweden)

    Range Maria Cristina

    2000-01-01

    Full Text Available O Problema Quadrático de Alocação (PQA pertence à classe dos problemas NP-Hard e desafia os pesquisadores tanto em sua teoria quanto em sua parte computacional. Pela sua alta complexidade muitos métodos heurísticos têm sido desenvolvidos para tentar resolvê-lo aproximadamente. A metaheurística GRASP (greedy randomized adaptive search procedures se mostrou bastante eficiente. Neste trabalho, uma proposta para descartar soluções iniciais supostamente ruins é apresentada com base na normalização de custos calculadas num intervalo entre limites de solução. Para este GRASP restrito, foi observada uma redução do tempo computacional para encontrar as soluções ótimas ou soluções viáveis de boa qualidade quando comparado ao GRASP original.

  20. Design and validation of a morphing myoelectric hand posture controller based on principal component analysis of human grasping.

    Science.gov (United States)

    Segil, Jacob L; Weir, Richard F ff

    2014-03-01

    An ideal myoelectric prosthetic hand should have the ability to continuously morph between any posture like an anatomical hand. This paper describes the design and validation of a morphing myoelectric hand controller based on principal component analysis of human grasping. The controller commands continuously morphing hand postures including functional grasps using between two and four surface electromyography (EMG) electrodes pairs. Four unique maps were developed to transform the EMG control signals in the principal component domain. A preliminary validation experiment was performed by 10 nonamputee subjects to determine the map with highest performance. The subjects used the myoelectric controller to morph a virtual hand between functional grasps in a series of randomized trials. The number of joints controlled accurately was evaluated to characterize the performance of each map. Additional metrics were studied including completion rate, time to completion, and path efficiency. The highest performing map controlled over 13 out of 15 joints accurately.

  1. Comment on "Ducklings imprint on the relational concept of 'same or different'".

    Science.gov (United States)

    Langbein, Jan; Puppe, Birger

    2017-02-24

    Martinho and Kacelnik (Reports, 15 July 2016, p. 286) reported that newly hatched ducklings imprinted on relational concepts. We argue that reanalyzing the data at the individual level shows that this conclusion cannot be applied for all sets of stimuli presented and that the ability to grasp relational concepts is limited to the stimulus category that is most beneficial for survival. Copyright © 2017, American Association for the Advancement of Science.

  2. Visually and memory-guided grasping: aperture shaping exhibits a time-dependent scaling to Weber's law.

    Science.gov (United States)

    Holmes, Scott A; Mulla, Ali; Binsted, Gordon; Heath, Matthew

    2011-09-01

    The 'just noticeable difference' (JND) represents the minimum amount by which a stimulus must change to produce a noticeable variation in one's perceptual experience and is related to initial stimulus magnitude (i.e., Weber's law). The goal of the present study was to determine whether aperture shaping for visually derived and memory-guided grasping elicit a temporally dependent or temporally independent adherence to Weber's law. Participants were instructed to grasp differently sized objects (20, 30, 40, 50 and 60mm) in conditions wherein vision of the grasping environment was available throughout the response (i.e., closed-loop), when occluded at movement onset (i.e., open-loop), and when occluded for a brief (i.e., 0ms) or longer (i.e., 2000ms) delay in advance of movement onset. Within-participant standard deviations of grip aperture (i.e., the JNDs) computed at decile increments of normalized grasping time were used to determine participant's sensitivity to detecting changes in object size. Results showed that JNDs increased linearly with increasing object size from 10% to 40% of grasping time; that is, the trial-to-trial stability (i.e., visuomotor certainty) of grip aperture (i.e., the comparator) decreased with increasing object size (i.e., the initial stimulus). However, a null JND/object size scaling was observed during the middle and late stages of the response (i.e., >50% of grasping time). Most notably, the temporal relationship between JNDs and object size scaling was similar across the different visual conditions used here. Thus, our results provide evidence that aperture shaping elicits a time-dependent early, but not late, adherence to the psychophysical principles of Weber's law. Copyright © 2011 Elsevier Ltd. All rights reserved.

  3. Left neglected, but only in far space: Spatial biases in healthy participants revealed in a visually-guided grasping task

    Directory of Open Access Journals (Sweden)

    Natalie ede Bruin

    2014-01-01

    Full Text Available Hemispatial neglect is a common outcome of stroke that is characterised by the inability to orient towards, and attend to stimuli in contralesional space. It is established that hemispatial neglect has a perceptual component, however, the presence and severity of motor impairments is controversial. Establishing the nature of space use and spatial biases during visually-guided actions amongst healthy individuals is critical to understanding the presence of visuomotor deficits in patients with neglect. Accordingly, three experiments were conducted to investigate the effect of object spatial location on patterns of grasping. Experiment 1 required right-handed participants to reach and grasp for blocks in order to construct 3D models. The blocks were scattered on a tabletop divided into equal size quadrants: left near, left far, right near, and right far. Identical sets of building blocks were available in each quadrant. Space use was dynamic, with participants initially grasping blocks from right near space and tending to ‘neglect’ left far space until the final stages of the task. Experiment 2 repeated the protocol with left-handed participants. Remarkably, left-handed participants displayed a similar pattern of space use to right-handed participants. In Experiment 3 eye movements were examined to investigate whether ‘neglect’ for grasping in left far reachable space had its origins in attentional biases. It was found that patterns of eye movements mirrored patterns of reach-to-grasp movements. We conclude that there are spatial biases during visually-guided grasping, specifically, a tendency to neglect left far reachable space, and that this ‘neglect’ is attentional in origin. The results raise the possibility that visuomotor impairments reported among patients with right hemisphere lesions when working in contralesional space may result in part from this inherent tendency to ‘neglect’ left far space irrespective of the presence

  4. Biological Principles and Threshold Concepts for Understanding Natural Selection. Implications for Developing Visualizations as a Pedagogic Tool

    Science.gov (United States)

    Tibell, Lena A. E.; Harms, Ute

    2017-11-01

    Modern evolutionary theory is both a central theory and an integrative framework of the life sciences. This is reflected in the common references to evolution in modern science education curricula and contexts. In fact, evolution is a core idea that is supposed to support biology learning by facilitating the organization of relevant knowledge. In addition, evolution can function as a pivotal link between concepts and highlight similarities in the complexity of biological concepts. However, empirical studies in many countries have for decades identified deficiencies in students' scientific understanding of evolution mainly focusing on natural selection. Clearly, there are major obstacles to learning natural selection, and we argue that to overcome them, it is essential to address explicitly the general abstract concepts that underlie the biological processes, e.g., randomness or probability. Hence, we propose a two-dimensional framework for analyzing and structuring teaching of natural selection. The first—purely biological—dimension embraces the three main principles variation, heredity, and selection structured in nine key concepts that form the core idea of natural selection. The second dimension encompasses four so-called thresholds, i.e., general abstract and/or non-perceptual concepts: randomness, probability, spatial scales, and temporal scales. We claim that both of these dimensions must be continuously considered, in tandem, when teaching evolution in order to allow development of a meaningful understanding of the process. Further, we suggest that making the thresholds tangible with the aid of appropriate kinds of visualizations will facilitate grasping of the threshold concepts, and thus, help learners to overcome the difficulties in understanding the central theory of life.

  5. Structural and functional anatomy of the palmaris brevis: grasping for answers.

    Science.gov (United States)

    Moore, Colin W; Rice, Charles L

    2017-12-01

    The palmaris brevis (PB) is a small cutaneous hand muscle that has been described as the most mysterious muscle from a functional and developmental perspective [Kaplan () Kaplan's Functional and Surgical Anatomy of the Hand]. Functionally, the PB is considered to deepen the hollow of the palm and to protect the neurovasculature of the ulnar canal. Although the function of the PB has been inferred from cadaveric observations, the electromyographic (EMG) activity of this muscle has not been explored systematically during specific movements of the hand. The purpose of this study was to record PB intramuscular EMG activity during dynamic grasping tasks, and to quantify the change in PB muscle length (M L ) and thickness (M T ) incurred during maximal contraction using ultrasound imaging. Intramuscular EMG was recorded from the PB in the dominant hands of 12 healthy participants (11 males, one female; age: 27 ± 4 years) during maximal abduction, flexion and opposition of the 5th digit, and two grasping tasks. Abduction of the 5th digit yielded the greatest EMG activity in most individuals (seven out of 11), and produced significantly less PB EMG activity when compared with grasping a cylindrical-shaped object (P = 0.003) but not a spherical-shaped object (P = 0.130). During maximal abduction of the 5th digit, PB M L decreased in both the left (28 ± 11%; P = 0.002) and right (32 ± 5%; P = 0.002) hands. Similarly, a concomitant increase in PB M T was observed in the left (68 ± 30%; P = 0.002) and right (85 ± 44%; P = 0.002) hands during the same contraction. These EMG results indicate that the PB is voluntarily activated during prehensile and non-prehensile movements of the hand with significant changes in muscle architecture. The study supports the preservation of the PB in surgical procedures based on its proposed protective role as a muscular barrier to the neurovasculature within the ulnar canal. © 2017 Anatomical Society.

  6. GRASP (Greedy Randomized Adaptive Search Procedures) applied to optimization of petroleum products distribution in pipeline networks; GRASP (Greedy Randomized Adaptative Search Procedures) aplicado ao 'scheduling' de redes de distribuicao de petroleo e derivados

    Energy Technology Data Exchange (ETDEWEB)

    Conte, Viviane Cristhyne Bini; Arruda, Lucia Valeria Ramos de; Yamamoto, Lia [Universidade Tecnologica Federal do Parana (UTFPR), Curitiba, PR (Brazil)

    2008-07-01

    Planning and scheduling of the pipeline network operations aim the most efficient use of the resources resulting in a better performance of the network. A petroleum distribution pipeline network is composed by refineries, sources and/or storage parks, connected by a set of pipelines, which operate the transportation of petroleum and derivatives among adjacent areas. In real scenes, this problem is considered a combinatorial problem, which has difficult solution, which makes necessary methodologies of the resolution that present low computational time. This work aims to get solutions that attempt the demands and minimize the number of batch fragmentations on the sent operations of products for the pipelines in a simplified model of a real network, through by application of the local search metaheuristic GRASP. GRASP does not depend of solutions of previous iterations and works in a random way so it allows the search for the solution in an ampler and diversified search space. GRASP utilization does not demand complex calculation, even the construction stage that requires more computational effort, which provides relative rapidity in the attainment of good solutions. GRASP application on the scheduling of the operations of this network presented feasible solutions in a low computational time. (author)

  7. Subcarrier multiplexing optical quantum key distribution

    International Nuclear Information System (INIS)

    Ortigosa-Blanch, A.; Capmany, J.

    2006-01-01

    We present the physical principles of a quantum key distribution system that opens the possibility of parallel quantum key distribution and, therefore, of a substantial improvement in the bit rate of such systems. Quantum mechanics allows for multiple measurements at different frequencies and thus we exploit this concept by extending the concept of frequency coding to the case where more than one radio-frequency subcarrier is used for independently encoding the bits onto an optical carrier. Taking advantage of subcarrier multiplexing techniques we demonstrate that the bit rate can be greatly improved as parallel key distribution is enabled

  8. Method of Grasping Control by Computing Internal and External Impedances for Two Robot Fingers, and Its Application to Admittance Control of a Robot Hand-Arm System

    Directory of Open Access Journals (Sweden)

    Jian Huang

    2015-08-01

    Full Text Available Impedance control is an important technology used in the grasping control of a robot hand. Numerous studies related to grasping algorithms have been reported in recent years, with the contact force between robot fingers and the object to be grasped being primarily discussed in most cases. Generally, a coupling effect occurs between the internal loop of the grasping operation and the external loop of the interaction with the environment when a multi-fingered robot hand is used to complete a contact task. Therefore, a robot hand cannot hold an object using a large external force to complete a wide range of tasks by applying the conventional method. In this paper, the coupling of the internal/external forces occurring in grasping operations using multiple fingers is analysed. Then, improved impedance control based on the previous method is proposed as an effective tool to solve the problem of grasping failure caused by single-finger contact. Furthermore, a method for applying the improved grasping algorithm to the admittance control of a robot hand-arm system is also proposed. The proposed method divides the impedance effect into the grasping control of the hand and the cooperative control of the arm, so that expanding the task space and increasing the flexibility of impedance adjustment can be achieved. Experiments were conducted to demonstrate the effectiveness of the proposed method.

  9. GRASP92: a package for large-scale relativistic atomic structure calculations

    Science.gov (United States)

    Parpia, F. A.; Froese Fischer, C.; Grant, I. P.

    2006-12-01

    Program summaryTitle of program: GRASP92 Catalogue identifier: ADCU_v1_1 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADCU_v1_1 Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland Licensing provisions: no Programming language used: Fortran Computer: IBM POWERstation 320H Operating system: IBM AIX 3.2.5+ RAM: 64M words No. of lines in distributed program, including test data, etc.: 65 224 No of bytes in distributed program, including test data, etc.: 409 198 Distribution format: tar.gz Catalogue identifier of previous version: ADCU_v1_0 Journal reference of previous version: Comput. Phys. Comm. 94 (1996) 249 Does the new version supersede the previous version?: Yes Nature of problem: Prediction of atomic spectra—atomic energy levels, oscillator strengths, and radiative decay rates—using a 'fully relativistic' approach. Solution method: Atomic orbitals are assumed to be four-component spinor eigenstates of the angular momentum operator, j=l+s, and the parity operator Π=βπ. Configuration state functions (CSFs) are linear combinations of Slater determinants of atomic orbitals, and are simultaneous eigenfunctions of the atomic electronic angular momentum operator, J, and the atomic parity operator, P. Lists of CSFs are either explicitly prescribed by the user or generated from a set of reference CSFs, a set of subshells, and rules for deriving other CSFs from these. Approximate atomic state functions (ASFs) are linear combinations of CSFs. A variational functional may be constructed by combining expressions for the energies of one or more ASFs. Average level (AL) functionals are weighted sums of energies of all possible ASFs that may be constructed from a set of CSFs; the number of ASFs is then the same as the number, n, of CSFs. Optimal level (OL) functionals are weighted sums of energies of some subset of ASFs; the GRASP92 package is optimized for this latter class of functionals. The composition of an ASF in terms

  10. The assessment of GRASP as a prospective ESA gamma ray astronomy mission

    International Nuclear Information System (INIS)

    Bignami, G.; Villa, G.; Dean, A.J.

    1987-01-01

    The GRASP mission - Gamma-Ray Astronomy with Spectroscopy and Positioning was originally proposed as a prospective European astronomy mission by the representatives of a wide European community. The project was selected by ESA for a detailed assessment study which was duly completed in December 1986. The telescope has been designed as a high quality spectral imager (E/ΔE∼1000, Δθ∼6') which operates over a wide spectral range (15 keV to >∼100 MeV) with a (3σ) sensitivity of typically 10 m Crab or better over the entire operational range within an observation period of 10 5 s. Two principal mission scenarios were considered

  11. Heuristic methods using grasp, path relinking and variable neighborhood search for the clustered traveling salesman problem

    Directory of Open Access Journals (Sweden)

    Mário Mestria

    2013-08-01

    Full Text Available The Clustered Traveling Salesman Problem (CTSP is a generalization of the Traveling Salesman Problem (TSP in which the set of vertices is partitioned into disjoint clusters and objective is to find a minimum cost Hamiltonian cycle such that the vertices of each cluster are visited contiguously. The CTSP is NP-hard and, in this context, we are proposed heuristic methods for the CTSP using GRASP, Path Relinking and Variable Neighborhood Descent (VND. The heuristic methods were tested using Euclidean instances with up to 2000 vertices and clusters varying between 4 to 150 vertices. The computational tests were performed to compare the performance of the heuristic methods with an exact algorithm using the Parallel CPLEX software. The computational results showed that the hybrid heuristic method using VND outperforms other heuristic methods.

  12. Decoding complete reach and grasp actions from local primary motor cortex populations.

    Science.gov (United States)

    Vargas-Irwin, Carlos E; Shakhnarovich, Gregory; Yadollahpour, Payman; Mislow, John M K; Black, Michael J; Donoghue, John P

    2010-07-21

    How the activity of populations of cortical neurons generates coordinated multijoint actions of the arm, wrist, and hand is poorly understood. This study combined multielectrode recording techniques with full arm motion capture to relate neural activity in primary motor cortex (M1) of macaques (Macaca mulatta) to arm, wrist, and hand postures during movement. We find that the firing rate of individual M1 neurons is typically modulated by the kinematics of multiple joints and that small, local ensembles of M1 neurons contain sufficient information to reconstruct 25 measured joint angles (representing an estimated 10 functionally independent degrees of freedom). Beyond showing that the spiking patterns of local M1 ensembles represent a rich set of naturalistic movements involving the entire upper limb, the results also suggest that achieving high-dimensional reach and grasp actions with neuroprosthetic devices may be possible using small intracortical arrays like those already being tested in human pilot clinical trials.

  13. GRASP with path-relinking for the selective pickup and delivery problem

    DEFF Research Database (Denmark)

    Ho, Sin C.; Szeto, W. Y.

    2016-01-01

    Bike sharing systems are very popular nowadays. One of the characteristics is that bikes are picked up from some surplus bike stations and transported to all deficit bike stations by a repositioning vehicle with limited capacity to satisfy the demand of deficit bike stations. Motivated by this real...... world bicycle repositioning problem, we study the selective pickup and delivery problem, where demand at every delivery node has to be satisfied by the supply collected from a subset of pickup nodes. The objective is to minimize the total travel cost incurred from visiting the nodes. We present a GRASP...... with path-relinking for solving the described problem. Experimental results show that this simple heuristic improves the existing results in the literature with an average improvement of 5.72% using small computing times. The proposed heuristic can contribute to the development of effective and efficient...

  14. Space Geodetic Technique Co-location in Space: Simulation Results for the GRASP Mission

    Science.gov (United States)

    Kuzmicz-Cieslak, M.; Pavlis, E. C.

    2011-12-01

    The Global Geodetic Observing System-GGOS, places very stringent requirements in the accuracy and stability of future realizations of the International Terrestrial Reference Frame (ITRF): an origin definition at 1 mm or better at epoch and a temporal stability on the order of 0.1 mm/y, with similar numbers for the scale (0.1 ppb) and orientation components. These goals were derived from the requirements of Earth science problems that are currently the international community's highest priority. None of the geodetic positioning techniques can achieve this goal alone. This is due in part to the non-observability of certain attributes from a single technique. Another limitation is imposed from the extent and uniformity of the tracking network and the schedule of observational availability and number of suitable targets. The final limitation derives from the difficulty to "tie" the reference points of each technique at the same site, to an accuracy that will support the GGOS goals. The future GGOS network will address decisively the ground segment and to certain extent the space segment requirements. The JPL-proposed multi-technique mission GRASP (Geodetic Reference Antenna in Space) attempts to resolve the accurate tie between techniques, using their co-location in space, onboard a well-designed spacecraft equipped with GNSS receivers, a SLR retroreflector array, a VLBI beacon and a DORIS system. Using the anticipated system performance for all four techniques at the time the GGOS network is completed (ca 2020), we generated a number of simulated data sets for the development of a TRF. Our simulation studies examine the degree to which GRASP can improve the inter-technique "tie" issue compared to the classical approach, and the likely modus operandi for such a mission. The success of the examined scenarios is judged by the quality of the origin and scale definition of the resulting TRF.

  15. Hybrid Feature Selection Approach Based on GRASP for Cancer Microarray Data

    Directory of Open Access Journals (Sweden)

    Arpita Nagpal

    2017-01-01

    Full Text Available Microarray data usually contain a large number of genes, but a small number of samples. Feature subset selection for microarray data aims at reducing the number of genes so that useful information can be extracted from the samples. Reducing the dimension of data sets further helps in improving the computational efficiency of the learning model. In this paper, we propose a modified algorithm based on the tabu search as local search procedures to a Greedy Randomized Adaptive Search Procedure (GRASP for high dimensional microarray data sets. The proposed Tabu based Greedy Randomized Adaptive Search Procedure algorithm is named as TGRASP. In TGRASP, a new parameter has been introduced named as Tabu Tenure and the existing parameters, NumIter and size have been modified. We observed that different parameter settings affect the quality of the optimum. The second proposed algorithm known as FFGRASP (Firefly Greedy Randomized Adaptive Search Procedure uses a firefly optimization algorithm in the local search optimzation phase of the greedy randomized adaptive search procedure (GRASP. Firefly algorithm is one of the powerful algorithms for optimization of multimodal applications. Experimental results show that the proposed TGRASP and FFGRASP algorithms are much better than existing algorithm with respect to three performance parameters viz. accuracy, run time, number of a selected subset of features. We have also compared both the approaches with a unified metric (Extended Adjusted Ratio of Ratios which has shown that TGRASP approach outperforms existing approach for six out of nine cancer microarray datasets and FFGRASP performs better on seven out of nine datasets.

  16. Grasping and Placing Operation for Labware Transportation in Life Science Laboratories using Mobile Robots

    Directory of Open Access Journals (Sweden)

    Mohammed Myasar Ali

    2017-07-01

    Full Text Available In automated working environments, mobile robots can be used for different purposes such as material handling, domestic services, and objects transportation. This work presents a grasping and placing operation for multiple labware and tube racks in life science laboratories using the H20 mobile robots. The H20 robot has dual arms where each arm consists of 6 revolute joints with 6-DOF and 2-DOF grippers. The labware, which have to be manipulated and transported, contain chemical and biological components. Therefore, an accurate approach for object recognition and position estimation is required. The recognition and pose estimation of the desired objects are very essential to guide the robotic arm in the manipulation tasks. In this work, the problem statement of H20 transportation system with the proposed methodology are presented. Different strategies (visual and non-visual of labware manipulation using mobile robots are described. The H20 robot is equipped with a Kinect V2 sensor to identify and estimate the position of the target. The local features recognition based on SURF algorithm (Speeded-Up Robust Features is used. The recognition process is performed for the required labware and holder to perform the grasping and placing operation. A strategy is proposed to find the required holder and to check its emptiness for the placing tasks. Different styles of grippers and labware containers are used to manipulate different weights of labware and to realize a safe transportation. The parts of mobile robot transportation system are communicated with each other using Asynchronous socket Channels.

  17. Classification of Anticipatory Signals for Grasp and Release from Surface Electromyography

    Science.gov (United States)

    Siu, Ho Chit; Shah, Julie A.; Stirling, Leia A.

    2016-01-01

    Surface electromyography (sEMG) is a technique for recording natural muscle activation signals, which can serve as control inputs for exoskeletons and prosthetic devices. Previous experiments have incorporated these signals using both classical and pattern-recognition control methods in order to actuate such devices. We used the results of an experiment incorporating grasp and release actions with object contact to develop an intent-recognition system based on Gaussian mixture models (GMM) and continuous-emission hidden Markov models (HMM) of sEMG data. We tested this system with data collected from 16 individuals using a forearm band with distributed sEMG sensors. The data contain trials with shifted band alignments to assess robustness to sensor placement. This study evaluated and found that pattern-recognition-based methods could classify transient anticipatory sEMG signals in the presence of shifted sensor placement and object contact. With the best-performing classifier, the effect of label lengths in the training data was also examined. A mean classification accuracy of 75.96% was achieved through a unigram HMM method with five mixture components. Classification accuracy on different sub-movements was found to be limited by the length of the shortest sub-movement, which means that shorter sub-movements within dynamic sequences require larger training sets to be classified correctly. This classification of user intent is a potential control mechanism for a dynamic grasping task involving user contact with external objects and noise. Further work is required to test its performance as part of an exoskeleton controller, which involves contact with actuated external surfaces. PMID:27792155

  18. Reach and grasp by people with tetraplegia using a neurally controlled robotic arm

    Science.gov (United States)

    Hochberg, Leigh R.; Bacher, Daniel; Jarosiewicz, Beata; Masse, Nicolas Y.; Simeral, John D.; Vogel, Joern; Haddadin, Sami; Liu, Jie; Cash, Sydney S.; van der Smagt, Patrick; Donoghue, John P.

    2012-01-01

    Paralysis following spinal cord injury (SCI), brainstem stroke, amyotrophic lateral sclerosis (ALS) and other disorders can disconnect the brain from the body, eliminating the ability to carry out volitional movements. A neural interface system (NIS)1–5 could restore mobility and independence for people with paralysis by translating neuronal activity directly into control signals for assistive devices. We have previously shown that people with longstanding tetraplegia can use an NIS to move and click a computer cursor and to control physical devices6–8. Able-bodied monkeys have used an NIS to control a robotic arm9, but it is unknown whether people with profound upper extremity paralysis or limb loss could use cortical neuronal ensemble signals to direct useful arm actions. Here, we demonstrate the ability of two people with long-standing tetraplegia to use NIS-based control of a robotic arm to perform three-dimensional reach and grasp movements. Participants controlled the arm over a broad space without explicit training, using signals decoded from a small, local population of motor cortex (MI) neurons recorded from a 96-channel microelectrode array. One of the study participants, implanted with the sensor five years earlier, also used a robotic arm to drink coffee from a bottle. While robotic reach and grasp actions were not as fast or accurate as those of an able-bodied person, our results demonstrate the feasibility for people with tetraplegia, years after CNS injury, to recreate useful multidimensional control of complex devices directly from a small sample of neural signals. PMID:22596161

  19. A Quasi-Experimental Examination: Cognitive Sequencing of Instruction Using Experiential Learning Theory for STEM Concepts in Agricultural Education

    Science.gov (United States)

    Smith, Kasee L.; Rayfield, John

    2017-01-01

    Understanding methods for effectively instructing STEM education concepts is essential in the current climate of education (Freeman, Marginson, & Tyler 2014). Kolb's experiential learning theory (ELT) outlines four specific modes of learning, based on preferences for grasping and transforming information. This quasi-experimental study was…

  20. Molecular Phylogenetics: Concepts for a Newcomer.

    Science.gov (United States)

    Ajawatanawong, Pravech

    Molecular phylogenetics is the study of evolutionary relationships among organisms using molecular sequence data. The aim of this review is to introduce the important terminology and general concepts of tree reconstruction to biologists who lack a strong background in the field of molecular evolution. Some modern phylogenetic programs are easy to use because of their user-friendly interfaces, but understanding the phylogenetic algorithms and substitution models, which are based on advanced statistics, is still important for the analysis and interpretation without a guide. Briefly, there are five general steps in carrying out a phylogenetic analysis: (1) sequence data preparation, (2) sequence alignment, (3) choosing a phylogenetic reconstruction method, (4) identification of the best tree, and (5) evaluating the tree. Concepts in this review enable biologists to grasp the basic ideas behind phylogenetic analysis and also help provide a sound basis for discussions with expert phylogeneticists.

  1. Upper Limb Rehabilitation Robot Powered by PAMs Cooperates with FES Arrays to Realize Reach-to-Grasp Trainings

    Science.gov (United States)

    Su, Chen; Jiang, Xiaobo

    2017-01-01

    The reach-to-grasp activities play an important role in our daily lives. The developed RUPERT for stroke patients with high stiffness in arm flexor muscles is a low-cost lightweight portable exoskeleton rehabilitation robot whose joints are unidirectionally actuated by pneumatic artificial muscles (PAMs). In order to expand the useful range of RUPERT especially for patients with flaccid paralysis, functional electrical stimulation (FES) is taken to activate paralyzed arm muscles. As both the exoskeleton robot driven by PAMs and the neuromuscular skeletal system under FES possess the highly nonlinear and time-varying characteristics, iterative learning control (ILC) is studied and is taken to control this newly designed hybrid rehabilitation system for reaching trainings. Hand function rehabilitation refers to grasping. Because of tiny finger muscles, grasping and releasing are realized by FES array electrodes and matrix scan method. By using the surface electromyography (EMG) technique, the subject's active intent is identified. The upper limb rehabilitation robot powered by PAMs cooperates with FES arrays to realize active reach-to-grasp trainings, which was verified through experiments. PMID:29065566

  2. XD-GRASP: Golden-angle radial MRI with reconstruction of extra motion-state dimensions using compressed sensing.

    Science.gov (United States)

    Feng, Li; Axel, Leon; Chandarana, Hersh; Block, Kai Tobias; Sodickson, Daniel K; Otazo, Ricardo

    2016-02-01

    To develop a novel framework for free-breathing MRI called XD-GRASP, which sorts dynamic data into extra motion-state dimensions using the self-navigation properties of radial imaging and reconstructs the multidimensional dataset using compressed sensing. Radial k-space data are continuously acquired using the golden-angle sampling scheme and sorted into multiple motion-states based on respiratory and/or cardiac motion signals derived directly from the data. The resulting undersampled multidimensional dataset is reconstructed using a compressed sensing approach that exploits sparsity along the new dynamic dimensions. The performance of XD-GRASP is demonstrated for free-breathing three-dimensional (3D) abdominal imaging, two-dimensional (2D) cardiac cine imaging and 3D dynamic contrast-enhanced (DCE) MRI of the liver, comparing against reconstructions without motion sorting in both healthy volunteers and patients. XD-GRASP separates respiratory motion from cardiac motion in cardiac imaging, and respiratory motion from contrast enhancement in liver DCE-MRI, which improves image quality and reduces motion-blurring artifacts. XD-GRASP represents a new use of sparsity for motion compensation and a novel way to handle motions in the context of a continuous acquisition paradigm. Instead of removing or correcting motion, extra motion-state dimensions are reconstructed, which improves image quality and also offers new physiological information of potential clinical value. © 2015 Wiley Periodicals, Inc.

  3. Upper Limb Rehabilitation Robot Powered by PAMs Cooperates with FES Arrays to Realize Reach-to-Grasp Trainings

    Directory of Open Access Journals (Sweden)

    Xikai Tu

    2017-01-01

    Full Text Available The reach-to-grasp activities play an important role in our daily lives. The developed RUPERT for stroke patients with high stiffness in arm flexor muscles is a low-cost lightweight portable exoskeleton rehabilitation robot whose joints are unidirectionally actuated by pneumatic artificial muscles (PAMs. In order to expand the useful range of RUPERT especially for patients with flaccid paralysis, functional electrical stimulation (FES is taken to activate paralyzed arm muscles. As both the exoskeleton robot driven by PAMs and the neuromuscular skeletal system under FES possess the highly nonlinear and time-varying characteristics, iterative learning control (ILC is studied and is taken to control this newly designed hybrid rehabilitation system for reaching trainings. Hand function rehabilitation refers to grasping. Because of tiny finger muscles, grasping and releasing are realized by FES array electrodes and matrix scan method. By using the surface electromyography (EMG technique, the subject’s active intent is identified. The upper limb rehabilitation robot powered by PAMs cooperates with FES arrays to realize active reach-to-grasp trainings, which was verified through experiments.

  4. Getting hold of approaching objects : In search of a common control of hand-closure initiation in catching and grasping

    NARCIS (Netherlands)

    van de Kamp, Cornelis; Bongers, Raoul M.; Zaal, Frank T. J. M.

    Both in the catching and grasping component of prehension, the hand opens and closes before hand-object contact is made. The initiation of hand closure has to be coordinated with the time course of the decrease of the distance between the hand and the target object, i.e., with the reaching component

  5. Fingertip force planning during grasp is disrupted by impaired sensorimotor integration in children with hemiplegic cerebral palsy

    NARCIS (Netherlands)

    Gordon, A.M.; Charles, J.; Steenbergen, B.

    2006-01-01

    In the present study we examine the ability of children with hemiplegic cerebral palsy (CP) to use anticipatory control of fingertip forces during grasping, and whether anticipatory control is facilitated by lifts with the contralateral hand. Eight children with CP (age 4-13) were asked to perform

  6. Coordination of Reach-to-Grasp Kinematics in Individuals With Childhood-Onset Dystonia Due to Hemiplegic Cerebral Palsy.

    Science.gov (United States)

    Kukke, Sahana N; Curatalo, Lindsey A; de Campos, Ana Carolina; Hallett, Mark; Alter, Katharine E; Damiano, Diane L

    2016-05-01

    Functional reaching is impaired in dystonia. Here, we analyze upper extremity kinematics to quantify timing and coordination abnormalities during unimanual reach-to-grasp movements in individuals with childhood-onset unilateral wrist dystonia. Kinematics were measured during movements of both upper limbs in a patient group ( n = 11, age = 17.5 ±5 years), and a typically developing control group ( n = 9, age = 16.6 ±5 years). Hand aperture was computed to study the coordination of reach and grasp. Time-varying joint synergies within one upper limb were calculated using a novel technique based on principal component analysis to study intra-limb coordination. In the non-dominant arm, results indicate reduced coordination between reach and grasp in patients who could not lift the grasped object compared to those who could lift it. Lifters exhibit incoordination in distal upper extremity joints later in the movement and non-lifters lacked coordination throughout the movement and in the whole upper limb. The amount of atypical coordination correlates with dystonia severity in patients. Reduced coordination during movement may reflect deficits in the execution of simultaneous movements, motor planning, or muscle activation. Rehabilitation efforts can focus on particular time points when kinematic patterns deviate abnormally to improve functional reaching in individuals with childhood-onset dystonia.

  7. Learning Abstract Physical Concepts from Experience: Design and Use of an RC Circuit

    Science.gov (United States)

    Parra, Alfredo; Ordenes, Jorge; de la Fuente, Milton

    2018-05-01

    Science learning for undergraduate students requires grasping a great number of theoretical concepts in a rather short time. In our experience, this is especially difficult when students are required to simultaneously use abstract concepts, mathematical reasoning, and graphical analysis, such as occurs when learning about RC circuits. We present a simple experimental model in this work that allows students to easily design, build, and analyze RC circuits, thus providing an opportunity to test personal ideas, build graphical descriptions, and explore the meaning of the respective mathematical models, ultimately gaining a better grasp of the concepts involved. The result suggests that the simple setup indeed helps untrained students to visualize the essential points of this kind of circuit.

  8. Comment on: "Recent revisions of phosphate rock reserves and resources: a critique" by Edixhoven et al. (2014) - clarifying comments and thoughts on key conceptions, conclusions and interpretation to allow for sustainable action

    Science.gov (United States)

    Scholz, R. W.; Wellmer, F.-W.

    2016-02-01

    , innovation for exploiting low-grade deposits, etc.) is acknowledged, but the right conclusions are not drawn, including the mixing of finiteness and staticness, and the way in which the critique of the USGS upgrading of the Moroccan reserves has been linked to Peak P. In particular, we clarify that reserves are primarily company data that serve mining companies for their strategic planning and may, by no means, be used as proxy data for providing global Peak P estimates. Likewise, we elaborate that drilling plans for assessing reserves have to be adjusted to site characteristics, in particular, in the case of four plateaus in Morocco and the Western Sahara comprising an area greater than 10 000 km2. We reconstruct the IFDC and USGS estimates and conclude that there is no evidence for considering the somewhat surprising increase to 50 Gt phosphate concentrate to be an unreasonable estimate for Moroccan reserves. However, the partial mixing of different units (e.g., phosphate ore and phosphate concentrate or marketable product) in the USGS data may be avoided by improving the database and using proper conversion factors. When applying these factors and assessing all reserves of marketable Gt of phosphate rock (PR-M), which is a common scale for measuring annual consumption, the magnitude of the 2014 USGS estimates of 67 Gt PR reserves does not change essentially but decreases from 64 (IFDC assessment) to 57.5 Gt PR-M (a worst-case calculation). We agree that a better harmonization of the (national) classification systems is meaningful. The discussion includes several ideas and thoughts that go beyond the paper by Edixhoven et al. (2014). We suggest that the discrepancies in the resource estimates are often caused by missing system understandings, different conceptions of sciences, and diverging world views. Finally, we suggest the establishment of a solidly funded, international standing committee that regularly analyzes global geopotential for assuring long-term supply

  9. Common tester platform concept.

    Energy Technology Data Exchange (ETDEWEB)

    Hurst, Michael James

    2008-05-01

    This report summarizes the results of a case study on the doctrine of a common tester platform, a concept of a standardized platform that can be applicable across the broad spectrum of testing requirements throughout the various stages of a weapons program, as well as across the various weapons programs. The common tester concept strives to define an affordable, next-generation design that will meet testing requirements with the flexibility to grow and expand; supporting the initial development stages of a weapons program through to the final production and surveillance stages. This report discusses a concept investing key leveraging technologies and operational concepts combined with prototype tester-development experiences and practical lessons learned gleaned from past weapons programs.

  10. Putting Order into Our Universe: The Concept of Blended Learning—A Methodology within the Concept-based Terminology Framework

    Directory of Open Access Journals (Sweden)

    Joana Fernandes

    2016-06-01

    Full Text Available This paper aims at discussing the advantages of a methodology design grounded on a concept-based approach to Terminology applied to the most prominent scenario of current Higher Education: blended learning. Terminology is a discipline that aims at representing, describing and defining specialized knowledge through language, putting order into our universe (Nuopponen, 2011. Concepts, as elements of the structure of knowledge (Sager, 1990 emerge as a complex research object. Can they be found in language? A concept-based approach to Terminology implies a clear-cut view of the role of language in terminological work: though language is postulated as being a fundamental tool to grasp, describe and organize knowledge, an isomorphic relationship between language and knowledge cannot be taken for granted. In other words, the foundational premise of a concept-based approach is that there is no one-to-one correspondence between atomic elements of knowledge and atomic elements of linguistic expression. This is why a methodological approach to Terminology merely based upon specialized text research is regarded as biased (Costa, 2013. As a consequence, we argue that interactional strategies between terminologist and domain expert deserve particular research attention. To our mind, the key to concept-based terminological work is to carry out a concept analysis of data gathered from a specialised text corpora combined with an elicitation process of the tacit knowledge and concept-oriented discursive negotiation. Following such view, we put forward a methodology to answer the question: how is blended learning defined in the Post-Bologna scenario? Even though there are numerous high-quality models and practical descriptions for its implementation (similarly to other concepts related to distance learning, the need to understand, demarcate and harmonize the concept of blended learning against the current Higher Education background results from the premise that

  11. Quantum key management

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, Richard John; Thrasher, James Thomas; Nordholt, Jane Elizabeth

    2016-11-29

    Innovations for quantum key management harness quantum communications to form a cryptography system within a public key infrastructure framework. In example implementations, the quantum key management innovations combine quantum key distribution and a quantum identification protocol with a Merkle signature scheme (using Winternitz one-time digital signatures or other one-time digital signatures, and Merkle hash trees) to constitute a cryptography system. More generally, the quantum key management innovations combine quantum key distribution and a quantum identification protocol with a hash-based signature scheme. This provides a secure way to identify, authenticate, verify, and exchange secret cryptographic keys. Features of the quantum key management innovations further include secure enrollment of users with a registration authority, as well as credential checking and revocation with a certificate authority, where the registration authority and/or certificate authority can be part of the same system as a trusted authority for quantum key distribution.

  12. The Integral Fast Reactor concept

    International Nuclear Information System (INIS)

    Till, C.E.; Chang, Y.I.

    1986-01-01

    The Integral Fast Reactor (IFR) is an innovative LMR concept, being developed at Argonne National Laboratory, that exploits the inherent properties of liquid metal cooling and metallic fuel to achieve breakthroughs in economics and inherent safety. This paper describes the key features and potential advantages of the IFR concept, its technology development status, fuel cycle economics potential, and its future development path

  13. Force Myography for Monitoring Grasping in Individuals with Stroke with Mild to Moderate Upper-Extremity Impairments: A Preliminary Investigation in a Controlled Environment

    Directory of Open Access Journals (Sweden)

    Gautam P. Sadarangani

    2017-07-01

    Full Text Available There is increasing research interest in technologies that can detect grasping, to encourage functional use of the hand as part of daily living, and thus promote upper-extremity motor recovery in individuals with stroke. Force myography (FMG has been shown to be effective for providing biofeedback to improve fine motor function in structured rehabilitation settings, involving isolated repetitions of a single grasp type, elicited at a predictable time, without upper-extremity movements. The use of FMG, with machine learning techniques, to detect and distinguish between grasping and no grasping, continues to be an active area of research, in healthy individuals. The feasibility of classifying FMG for grasp detection in populations with upper-extremity impairments, in the presence of upper-extremity movements, as would be expected in daily living, has yet to be established. We explore the feasibility of FMG for this application by establishing and comparing (1 FMG-based grasp detection accuracy and (2 the amount of training data necessary for accurate grasp classification, in individuals with stroke and healthy individuals. FMG data were collected using a flexible forearm band, embedded with six force-sensitive resistors (FSRs. Eight participants with stroke, with mild to moderate upper-extremity impairments, and eight healthy participants performed 20 repetitions of three tasks that involved reaching, grasping, and moving an object in different planes of movement. A validation sensor was placed on the object to label data as corresponding to a grasp or no grasp. Grasp detection performance was evaluated using linear and non-linear classifiers. The effect of training set size on classification accuracy was also determined. FMG-based grasp detection demonstrated high accuracy of 92.2% (σ = 3.5% for participants with stroke and 96.0% (σ = 1.6% for healthy volunteers using a support vector machine (SVM. The use of a training set that was 50

  14. Group key management

    Energy Technology Data Exchange (ETDEWEB)

    Dunigan, T.; Cao, C.

    1997-08-01

    This report describes an architecture and implementation for doing group key management over a data communications network. The architecture describes a protocol for establishing a shared encryption key among an authenticated and authorized collection of network entities. Group access requires one or more authorization certificates. The implementation includes a simple public key and certificate infrastructure. Multicast is used for some of the key management messages. An application programming interface multiplexes key management and user application messages. An implementation using the new IP security protocols is postulated. The architecture is compared with other group key management proposals, and the performance and the limitations of the implementation are described.

  15. [Process and key points of clinical literature evaluation of post-marketing traditional Chinese medicine].

    Science.gov (United States)

    Liu, Huan; Xie, Yanming

    2011-10-01

    The clinical literature evaluation of the post-marketing traditional Chinese medicine is a comprehensive evaluation by the comprehensive gain, analysis of the drug, literature of drug efficacy, safety, economy, based on the literature evidence and is part of the evaluation of evidence-based medicine. The literature evaluation in the post-marketing Chinese medicine clinical evaluation is in the foundation and the key position. Through the literature evaluation, it can fully grasp the information, grasp listed drug variety of traditional Chinese medicines second development orientation, make clear further clinical indications, perfect the medicines, etc. This paper discusses the main steps and emphasis of the clinical literature evaluation. Emphasizing security literature evaluation should attach importance to the security of a comprehensive collection drug information. Safety assessment should notice traditional Chinese medicine validity evaluation in improving syndrome, improveing the living quality of patients with special advantage. The economics literature evaluation should pay attention to reliability, sensitivity and practicability of the conclusion.

  16. COMET concept

    International Nuclear Information System (INIS)

    Alsmeyer, H.; Tromm, W.

    1995-01-01

    Studies of the COMET core catcher concept developed for a future PWR have been continued. The concept is based on the spreading of a core melt on a sacrificial layer and its erosion, until a subsequent addition of water from below causes a fragmentation of the melt. A porous solidification of the melt would then admit a complete flooding within a short period. (orig.)

  17. Concept Mapping

    Science.gov (United States)

    Technology & Learning, 2005

    2005-01-01

    Concept maps are graphical ways of working with ideas and presenting information. They reveal patterns and relationships and help students to clarify their thinking, and to process, organize and prioritize. Displaying information visually--in concept maps, word webs, or diagrams--stimulates creativity. Being able to think logically teaches…

  18. Management concepts.

    Science.gov (United States)

    Bittner, Rhonda

    2006-01-01

    Management concepts evolve through time. Health care managers can learn new concepts by evaluating classical management strategies, as well as modern-day strategies. Focusing on quality improvement and team building can help managers align the goals of their departments with the goals of the organization, consequently improving patient care.

  19. Lateral Concepts

    DEFF Research Database (Denmark)

    Gad, Christopher; Bruun Jensen, casper

    2016-01-01

    This essay discusses the complex relation between the knowledges and practices of the researcher and his/her informants in terms of lateral concepts. The starting point is that it is not the prerogative of the (STS) scholar to conceptualize the world; all our “informants” do it too. This creates...... the possibility of enriching our own conceptual repertoires by letting them be inflected by the concepts of those we study. In a broad sense, the lateral means that there is a many-to-many relation between domains of knowledge and practice. However, each specific case of the lateral is necessarily immanent...... to a particular empirical setting and form of inquiry. In this sense lateral concepts are radically empirical since it locates concepts within the field. To clarify the meaning and stakes of lateral concepts, we first make a contrast between lateral anthropology and Latour’s notion of infra-reflexivity. We end...

  20. Concept theory

    DEFF Research Database (Denmark)

    Hjørland, Birger

    2009-01-01

      Concept theory is an extremely broad, interdisciplinary and complex field of research related to many deep fields with very long historical traditions without much consensus. However, information science and knowledge organization cannot avoid relating to theories of concepts. Knowledge...... organizing systems (e.g. classification systems, thesauri and ontologies) should be understood as systems basically organizing concepts and their semantic relations. The same is the case with information retrieval systems. Different theories of concepts have different implications for how to construe......, evaluate and use such systems. Based on "a post-Kuhnian view" of paradigms this paper put forward arguments that the best understanding and classification of theories of concepts is to view and classify them in accordance with epistemological theories (empiricism, rationalism, historicism and pragmatism...

  1. Biometry, the safe key

    Directory of Open Access Journals (Sweden)

    María Fraile-Hurtado

    2010-12-01

    Full Text Available Biometry is the next step in authentication, why do not we take this stepforward in our communication security systems? Keys are the main disadvantage in the cryptography, what if we were our own key?

  2. Financial Key Ratios

    OpenAIRE

    Tănase Alin-Eliodor

    2014-01-01

    This article focuses on computing techniques starting from trial balance data regarding financial key ratios. There are presented activity, liquidity, solvency and profitability financial key ratios. It is presented a computing methodology in three steps based on a trial balance.

  3. Public Key Cryptography.

    Science.gov (United States)

    Tapson, Frank

    1996-01-01

    Describes public key cryptography, also known as RSA, which is a system using two keys, one used to put a message into cipher and another used to decipher the message. Presents examples using small prime numbers. (MKR)

  4. Key Management Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — FUNCTION: Provides a secure environment to research and develop advanced electronic key management and networked key distribution technologies for the Navy and DoD....

  5. Public Key Infrastructure Study

    National Research Council Canada - National Science Library

    Berkovits, Shimshon

    1994-01-01

    The National Institute of Standards and Technology (NIST) has tasked The MITRE Corporation to study the alternatives for automated management of public keys and of the associated public key certificates for the Federal Government...

  6. Symmetric autocompensating quantum key distribution

    Science.gov (United States)

    Walton, Zachary D.; Sergienko, Alexander V.; Levitin, Lev B.; Saleh, Bahaa E. A.; Teich, Malvin C.

    2004-08-01

    We present quantum key distribution schemes which are autocompensating (require no alignment) and symmetric (Alice and Bob receive photons from a central source) for both polarization and time-bin qubits. The primary benefit of the symmetric configuration is that both Alice and Bob may have passive setups (neither Alice nor Bob is required to make active changes for each run of the protocol). We show that both the polarization and the time-bin schemes may be implemented with existing technology. The new schemes are related to previously described schemes by the concept of advanced waves.

  7. Development of a non-invasive, multifunctional grasp neuroprosthesis and its evaluation in an individual with a high spinal cord injury.

    Science.gov (United States)

    Rupp, Rüdiger; Kreilinger, Alex; Rohm, Martin; Kaiser, Vera; Müller-Putz, Gernot R

    2012-01-01

    Over the last decade the improvement of a missing hand function by application of neuroprostheses in particular the implantable Freehand system has been successfully shown in high spinal cord injured individuals. The clinically proven advantages of the Freehand system is its ease of use, the reproducible generation of two distinct functional grasp patterns and an analog control scheme based on movements of the contralateral shoulder. However, after the Freehand system is not commercially available for more than ten years, alternative grasp neuroprosthesis with a comparable functionality are still missing. Therefore, the aim of this study was to develop a non-invasive neuroprosthesis and to show that a degree of functional restoration can be provided to end users comparable to implanted devices. By introduction of an easy to handle forearm electrode sleeve the reproducible generation of two grasp patterns has been achieved. Generated grasp forces of the palmar grasp are in the range of the implanted system. Though pinch force of the lateral grasp is significantly lower, it can effectively used by a tetraplegic subject to perform functional tasks. The non-invasive grasp neuroprosthesis developed in this work may serve as an easy to apply and inexpensive way to restore a missing hand and finger function at any time after spinal cord injury.

  8. The Key Lake project

    International Nuclear Information System (INIS)

    1991-01-01

    Key Lake is located in the Athabasca sand stone basin, 640 kilometers north of Saskatoon, Saskatchewan, Canada. The three sources of ore at Key Lake contain 70 100 tonnes of uranium. Features of the Key Lake Project were described under the key headings: work force, mining, mill process, tailings storage, permanent camp, environmental features, worker health and safety, and economic benefits. Appendices covering the historical background, construction projects, comparisons of western world mines, mining statistics, Northern Saskatchewan surface lease, and Key Lake development and regulatory agencies were included

  9. Space Mission Concept Development Using Concept Maturity Levels

    Science.gov (United States)

    Wessen, Randii R.; Borden, Chester; Ziemer, John; Kwok, Johnny

    2013-01-01

    Over the past five years, pre-project formulation experts at the Jet Propulsion Laboratory (JPL) has developed and implemented a method for measuring and communicating the maturity of space mission concepts. Mission concept development teams use this method, and associated tools, prior to concepts entering their Formulation Phases (Phase A/B). The organizing structure is Concept Maturity Level (CML), which is a classification system for characterizing the various levels of a concept's maturity. The key strength of CMLs is the ability to evolve mission concepts guided by an incremental set of assessment needs. The CML definitions have been expanded into a matrix form to identify the breadth and depth of analysis needed for a concept to reach a specific level of maturity. This matrix enables improved assessment and communication by addressing the fundamental dimensions (e.g., science objectives, mission design, technical risk, project organization, cost, export compliance, etc.) associated with mission concept evolution. JPL's collaborative engineering, dedicated concept development, and proposal teams all use these and other CML-appropriate design tools to advance their mission concept designs. This paper focuses on mission concept's early Pre-Phase A represented by CMLs 1- 4. The scope was limited due to the fact that CMLs 5 and 6 are already well defined based on the requirements documented in specific Announcement of Opportunities (AO) and Concept Study Report (CSR) guidelines, respectively, for competitive missions; and by NASA's Procedural Requirements NPR 7120.5E document for Projects in their Formulation Phase.

  10. LOCKS AND KEYS SERVICE

    CERN Multimedia

    Locks and Keys Service

    2002-01-01

    The Locks and Keys service (ST/FM) will move from building 55 to building 570 from the 2nd August to the 9th August 2002 included. During this period the service will be closed. Only in case of extreme urgency please call the 164550. Starting from Monday, 12th August, the Locks and Keys Service will continue to follow the activities related to office keys (keys and locks) and will provide the keys for furniture. The service is open from 8h30 to 12h00 and from 13h00 to 17h30. We remind you that your divisional correspondents can help you in the execution of the procedures. We thank you for your comprehension and we remain at your service to help you in solving all the matters related to keys for offices and furniture. Locks and Keys Service - ST Division - FM Group

  11. A concept analysis of befriending.

    Science.gov (United States)

    Balaam, Marie-Clare

    2015-01-01

    To report an analysis of the concept of befriending. Befriending is an intervention used in a range of nursing, health and social care settings to provide support for individuals who are socially isolated or lack social support. However, in many cases befriending and its impact remains poorly understood and under researched. Concept analysis provides clarification of the concept and basis for further research and development. Concept analysis. AMED, Psyc Articles, Psych Info, Medline, MedlinePlus, Social Science Index and CINHAL databases were searched for literature published between 1993-2013 using the search term Befriending. Walker and Avant's method of concept analysis was chosen. This combined with insights from Risjord's work produced a theoretical concept analysis which focused on the concept in peer reviewed academic literature. There are currently several ways the mechanisms of befriending and its effects on individuals and communities are understood. It is possible however to identify key attributes which define the concept and differentiate it from related concepts, such as peer support and mentoring. Key attributes are that it is an organised intervention, involving the creation of an emotionally connected friend-like relationship, where there is a negotiation of power. This concept analysis has clarified current understandings and uses of befriending. It provides the basis for widening the focus of research into the effectiveness and impact of befriending on those who are befriended, those who befriend and the communities where befriending takes place. © 2014 John Wiley & Sons Ltd.

  12. Travelling Concepts

    DEFF Research Database (Denmark)

    Simonsen, Karen-Margrethe

    2013-01-01

    Review of "Travelling Concepts, Metaphors, and Narratives: Literary and Cultural Studies in an Age of Interdisciplinary Research" ed. by Sibylle Baumgarten, Beatrice Michaelis and Ansagar Nünning, Trier; Wissenschaftlicher Verlag Trier, 2012......Review of "Travelling Concepts, Metaphors, and Narratives: Literary and Cultural Studies in an Age of Interdisciplinary Research" ed. by Sibylle Baumgarten, Beatrice Michaelis and Ansagar Nünning, Trier; Wissenschaftlicher Verlag Trier, 2012...

  13. Seamless Control of Multi-Fingered Robot Hands Based on Grasp Polyhedrons

    Science.gov (United States)

    Nagase, Kenji; Shirai, Satoshi; Hayashi, Tsuyoshi

    This paper is concerned with a new feedback control design methodology for multi-fingered robot hands applicable to multiple contact situations. As a first step, we especially consider the situations where all the fingers are in contact or not in contact with an object, considering the tasks of catching and releasing the object preceding to or followed by grasping/manipulating the object. Main features of the proposed method are: (1) the direction of the fingertip motion in the non-contact situation is selected to be directly linked to the direction of the object motion and the internal force in the contact situation; (2) by introducing a unified system description for multiple contact situations, a linearizing compensator applicable to multiple contact situations is designed. The controller can handle the tasks with the multiple contact situations by choosing appropriate desired trajectories for the linearizing compensator without switching control architecture. In addition, owing to the selection of the motion in the non-contact situation, all the fingers can approach to the object synchronously along the directions of the object motion and the internal force in the contact situation. A numerical example is shown to prove effectiveness of the proposed method.

  14. An under-actuated origami gripper with adjustable stiffness joints for multiple grasp modes

    Science.gov (United States)

    Firouzeh, Amir; Paik, Jamie

    2017-05-01

    Under-actuated robots offer multiple degrees of freedom without much added complexity to the actuation and control. Utilizing adjustable stiffness joints in these robots allows us to control their stable configurations and their mode of interaction with the environment. In this paper, we present the design of tendon-driven robotic origami (robogami) joints with adjustable stiffness. The proposed designs allow us to place joints along any direction in the plane of the robot and in the normal direction to the plane. The layer-by-layer manufacturing of robogamis facilitates the design and manufacturing of robots with different arrangement of joints for different applications. We use thermally activated shape memory polymer to control the joint stiffness. The manufacturing of the polymer layer is compatible with the layer-by-layer manufacturing process of the robogamis which results in scalable and customizable robots. To demonstrate, we prototyped an under-actuated gripper with three fingers and only one input actuation. The grasp mode of the gripper is set by adjusting the configuration of the locked joints and modulating the stiffness of the active joints. We present a model to estimate the configuration and the contact forces of the gripper at different settings that will assist us in design and control of future generation of under-actuated robogamis.

  15. Noninvasive Electroencephalogram Based Control of a Robotic Arm for Reach and Grasp Tasks

    Science.gov (United States)

    Meng, Jianjun; Zhang, Shuying; Bekyo, Angeliki; Olsoe, Jaron; Baxter, Bryan; He, Bin

    2016-01-01

    Brain-computer interface (BCI) technologies aim to provide a bridge between the human brain and external devices. Prior research using non-invasive BCI to control virtual objects, such as computer cursors and virtual helicopters, and real-world objects, such as wheelchairs and quadcopters, has demonstrated the promise of BCI technologies. However, controlling a robotic arm to complete reach-and-grasp tasks efficiently using non-invasive BCI has yet to be shown. In this study, we found that a group of 13 human subjects could willingly modulate brain activity to control a robotic arm with high accuracy for performing tasks requiring multiple degrees of freedom by combination of two sequential low dimensional controls. Subjects were able to effectively control reaching of the robotic arm through modulation of their brain rhythms within the span of only a few training sessions and maintained the ability to control the robotic arm over multiple months. Our results demonstrate the viability of human operation of prosthetic limbs using non-invasive BCI technology. PMID:27966546

  16. Morphology and function of the forelimb in arboreal frogs: specializations for grasping ability?

    Science.gov (United States)

    Manzano, Adriana S; Abdala, Virginia; Herrel, Anthony

    2008-09-01

    Frogs are characterized by a unique morphology associated with their saltatory lifestyle. Although variation in the form and function of the pelvic girdle and associated appendicular system related to specialized locomotor modes such as swimming or burrowing has been documented, the forelimbs have typically been viewed as relatively unspecialized. Yet, previous authors have noted versatility in forelimb function among arboreal frogs associated with feeding. Here we study the morphology and function of the forelimb and hand during locomotion in two species of arboreal frogs (Litoria caerulea and Phyllomedusa bicolor). Our data show a complex arrangement of the distal forelimb and hand musculature with some notable differences between species. Analyses of high-speed video and video fluoroscopy recordings show that forelimbs are used in alternating fashion in a diagonal sequence footfall pattern and that the position of the hand is adjusted when walking on substrates of different diameters. Electromyographic recordings show that the flexors of the hand are active during substrate contact, suggesting the use of gripping to generate a stabilizing torque. Measurements of grasping forces in vivo and during stimulation experiments show that both species, are capable of executing a so-called power grip but also indicates marked differences between species, in the magnitude of forces generated. Stimulation experiments showed an increased control of digit flexion in the more specialized of the two species, allowing it to execute a precision grip paralleled only by that seen in primates.

  17. A Synergy-Based Optimally Designed Sensing Glove for Functional Grasp Recognition.

    Science.gov (United States)

    Ciotti, Simone; Battaglia, Edoardo; Carbonaro, Nicola; Bicchi, Antonio; Tognetti, Alessandro; Bianchi, Matteo

    2016-06-02

    Achieving accurate and reliable kinematic hand pose reconstructions represents a challenging task. The main reason for this is the complexity of hand biomechanics, where several degrees of freedom are distributed along a continuous deformable structure. Wearable sensing can represent a viable solution to tackle this issue, since it enables a more natural kinematic monitoring. However, the intrinsic accuracy (as well as the number of sensing elements) of wearable hand pose reconstruction (HPR) systems can be severely limited by ergonomics and cost considerations. In this paper, we combined the theoretical foundations of the optimal design of HPR devices based on hand synergy information, i.e., the inter-joint covariation patterns, with textile goniometers based on knitted piezoresistive fabrics (KPF) technology, to develop, for the first time, an optimally-designed under-sensed glove for measuring hand kinematics. We used only five sensors optimally placed on the hand and completed hand pose reconstruction (described according to a kinematic model with 19 degrees of freedom) leveraging upon synergistic information. The reconstructions we obtained from five different subjects were used to implement an unsupervised method for the recognition of eight functional grasps, showing a high degree of accuracy and robustness.

  18. The coordination patterns observed when two hands reach-to-grasp separate objects.

    Science.gov (United States)

    Bingham, Geoffrey P; Hughes, Kirstie; Mon-Williams, Mark

    2008-01-01

    What determines coordination patterns when both hands reach to grasp separate objects at the same time? It is known that synchronous timing is preferred as the most stable mode of bimanual coordination. Nonetheless, normal unimanual prehension behaviour predicts asynchrony when the two hands reach towards unequal targets, with synchrony restricted to targets equal in size and distance. Additionally, sufficiently separated targets require sequential looking. Does synchrony occur in all cases because it is preferred in bimanual coordination or does asynchrony occur because of unimanual task constraints and the need for sequential looking? We investigated coordinative timing when participants (n = 8) moved their right (preferred) hand to the same object at a fixed distance but the left hand to objects of different width (3, 5, and 7 cm) and grip surface size (1, 2, and 3 cm) placed at different distances (20, 30, and 40 cm) over 270 randomised trials. The hand movements consisted of two components: (1) an initial component (IC) during which the hand reached towards the target while forming an appropriate grip aperture, stopping at (but not touching) the object; (2) a completion component (CC) during which the finger and thumb closed on the target. The two limbs started the IC together but did not interact until the deceleration phase when evidence of synchronisation began to appear. Nonetheless, asynchronous timing was present at the end of the IC and preserved through the CC even with equidistant targets. Thus, there was synchrony but requirements for visual information ultimately yielded asynchronous coordinative timing.

  19. To drink or grasp? How bullet ants ( Paraponera clavata) differentiate between sugars and proteins in liquids

    Science.gov (United States)

    Jandt, Jennifer; Larson, Hannah K.; Tellez, Peter; McGlynn, Terrence P.

    2013-12-01

    Flexibility in behavior can increase the likelihood that a forager may respond optimally in a fluctuating environment. Nevertheless, physiological or neuronal constraints may result in suboptimal responses to stimuli. We observed foraging workers of the giant tropical ant (also referred to as the "bullet ant"), Paraponera clavata, as they reacted to liquid solutions with varying concentrations of sugar and protein. We show that when protein/sucrose concentration is high, many bullet ants will often try to grasp at the droplet, rather than gather it by drinking. Because P. clavata actively hunt for prey, fixed action patterns and rapid responses to protein may be adaptively important, regardless of the medium in which it is presented. We conclude that, in P. clavata, food-handling decisions are made in response to the nutrient content of the food rather than the texture of the food. Further, we suggest that colonies that maintain a mixture of individuals with consistent fixed or flexible behavioral responses to food-handling decisions may be better adapted to fluctuating environmental conditions, and we propose future studies that could address this.

  20. A Synergy-Based Optimally Designed Sensing Glove for Functional Grasp Recognition

    Directory of Open Access Journals (Sweden)

    Simone Ciotti

    2016-06-01

    Full Text Available Achieving accurate and reliable kinematic hand pose reconstructions represents a challenging task. The main reason for this is the complexity of hand biomechanics, where several degrees of freedom are distributed along a continuous deformable structure. Wearable sensing can represent a viable solution to tackle this issue, since it enables a more natural kinematic monitoring. However, the intrinsic accuracy (as well as the number of sensing elements of wearable hand pose reconstruction (HPR systems can be severely limited by ergonomics and cost considerations. In this paper, we combined the theoretical foundations of the optimal design of HPR devices based on hand synergy information, i.e., the inter-joint covariation patterns, with textile goniometers based on knitted piezoresistive fabrics (KPF technology, to develop, for the first time, an optimally-designed under-sensed glove for measuring hand kinematics. We used only five sensors optimally placed on the hand and completed hand pose reconstruction (described according to a kinematic model with 19 degrees of freedom leveraging upon synergistic information. The reconstructions we obtained from five different subjects were used to implement an unsupervised method for the recognition of eight functional grasps, showing a high degree of accuracy and robustness.

  1. Muscle activation patterns in acceleration-based phases during reach-to-grasp movement.

    Science.gov (United States)

    Tokuda, Keisuke; Lee, Bumsuk; Shiihara, Yasufumi; Takahashi, Kazuhiro; Wada, Naoki; Shirakura, Kenji; Watanabe, Hideomi

    2016-11-01

    [Purpose] An earlier study divided reaching activity into characteristic phases based on hand velocity profiles. By synchronizing muscle activities and the acceleration profile, a phasing approach for reaching movement, based on hand acceleration profiles, was attempted in order to elucidate the roles of individual muscle activities in the different phases of the acceleration profile in reaching movements. [Subjects and Methods] Ten healthy volunteer subjects participated in this study. The aim was to electromyographically evaluate muscles around the shoulder, the upper trapezius, the anterior deltoid, the biceps brachii, and the triceps brachii, most of which have been used to evaluate arm motion, as well as the acceleration of the upper limb during simple reaching movement in the reach-to-grasp task. [Results] Analysis showed the kinematic trajectories of the acceleration during a simple biphasic profile of the reaching movement could be divided into four phases: increasing acceleration (IA), decreasing acceleration (DA), increasing deceleration (ID), and decreasing deceleration (DD). Muscles around the shoulder showed different activity patterns, which were closely associated with these acceleration phases. [Conclusion] These results suggest the important role of the four phases, derived from the acceleration trajectory, in the elucidation of the muscular mechanisms which regulate and coordinate the muscles around the shoulder in reaching movements.

  2. Concepts in Thermal Physics

    CERN Document Server

    Blundell, Stephen J

    2006-01-01

    This modern introduction to thermal physics contains a step-by-step presentation of the key concepts. The text is copiously illustrated and each chapter contains several worked examples. - ;An understanding of thermal physics is crucial to much of modern physics, chemistry and engineering. This book provides a modern introduction to the main principles that are foundational to thermal physics, thermodynamics, and statistical mechanics. The key concepts are carefully presented in a clear way, and new ideas are illustrated with copious worked examples as well as a description of the historical background to their discovery. Applications are presented to subjects as. diverse as stellar astrophysics, information and communication theory, condensed matter physics, and climate change. Each chapter concludes with detailed exercises. -

  3. Revisiting Style, a Key Concept in Literary Studies

    NARCIS (Netherlands)

    Herrmann, J. Berenike; van Dalen-Oskam, K.H.; Schöch, Christof

    2015-01-01

    Language and literary studies have studied style for centuries, and even since the advent of ›stylistics‹ as a discipline at the beginning of the twentieth century, definitions of ›style‹ have varied heavily across time, space and fields. Today, with increasingly large collections of literary texts

  4. Military Officer Personnel Management: Key Concepts and Statutory Provisions

    Science.gov (United States)

    2016-05-10

    Attention Deficit Hyperactivity Disorder ( ADHD ) “a. Attention Deficit Hyperactivity Disorder ( ADHD ) (314) UNLESS the...and pass Service-specific training periods with no prescribed medication for ADHD .” Diabetes “Diabetes mellitus (250) disorders , including: (1...current National Heart, Lung, and Blood Institute (NHLBI) standards.” Anxiety “History of anxiety disorders (300.01), anxiety disorder not

  5. Equivalence Revisited: A Key Concept in Modern Translation Theory

    Directory of Open Access Journals (Sweden)

    Sergio Bolaños Cuéllar

    2002-01-01

    Full Text Available En este artículo se propone analizar la importancia, relevancia y validez del concepto de equivalencia como una noción constitutiva en la teoría de la traducción. La equivalencia se define como una relación que se presenta entre un texto de una Lengua de Partida (LP y otro texto en la Lengua Meta (LM. Nuestra concepción sobre la equivalencia se apoya en la teoría moderna textolingüística que considera que el texto es la unidad de análisis del evento comunicativo y, dado que la traducción misma es un evento comunicativo, resulta lógico que deba estudiarse a partir de un enfoque moderno textolingüístico. Se hace un breve recuento para sustentar esta perspectiva. Sin embargo, no todos los teóricos modernos de la teoría de la traducción comparten este punto de vista y, por consiguiente, se analizan dos posiciones antagonistas en la teoría de la traducción así como la crítica contra las Teorías de Orientación Lingüística o Textual (TOT. Luego se discuten en forma detallada argumentos a favor y en contra de la noción de equivalencia en TOT y en TOC (Teorías de Orientación Contextual y se analizan las nuevas perspectivas. Por último, se discute el concepto de equivalencia en el marco del Modelo Traductológico Dinámico (MTD y se ejemplifica brevemente su aplicación en la crítica de la traducción.

  6. Key Concepts of Environmental Sustainability in Family and Consumer Sciences

    Science.gov (United States)

    Thompson, Nancy E.; Harden, Amy J.; Clauss, Barbara; Fox, Wanda S.; Wild, Peggy

    2012-01-01

    It is the vision of the American Association of Family & Consumer Sciences to be "recognized as the driving force in bringing people together to improve the lives of individuals, families, and communities" (AAFCS, 2010). Because of this focus on individuals and families and its well-established presence in American schools, family and consumer…

  7. Random electrodynamics : a classical foundation for key quantum concepts

    International Nuclear Information System (INIS)

    Sachidanandam, S.

    1981-01-01

    The model of random electrodynamics, in which electromagnetic particles are subjected, in a classical manner, to the forces of radiation damping and the fluctuating zero-point fields provides the framework in which the following results are obtained: (1) The precession dynamics of a long-lived, non-relativistic particle with a magnetic moment proportional to its spin, leads to a self-consistent determination of the spin value as one-half. (2) The internal dynamic underlying the intrinsic magnetic moment of a Dirac particle yields a classically visualizable picture of the spin-magnetic moment. (3) The Bose correlation among indistinguishable, non-interacting, spin-zero Particles arises from the coupling through the common- zero point fields and the radiation reaction fields when the particles are close together in both the r vector and the energy spaces. (4) The (exclusion principle-induced) correlation among identical, non-interacting magnetic particles with spin 1/2 is brought about by the coupling, (through the common fields of radiation reaction and the vacuum fluctuations), of the spins as well as the translational motions when the particles are close together in r vector and the energy spaces. (5) A dilute gas of free electrons has a Maxwellian distribution of velocities and the correct value of the djamagnetic moment in the presence of a magnetic field. Considerations on the centre of mass motion of a composite neutral particle lead to a simple resolution of the foundational paradoxes of statistical mechanics. (6) An approximate treatment of the hydrogen atom leads to a description of the evolution to the ground state at absolute zero and an estimation of the mass frequency and the line-width of the radiation emitted when an excited atom decays. (author)

  8. Key technologies and concepts for beyond-3G networks

    Science.gov (United States)

    Pehkonen, Kari; Uskela, Sami; Kalliojarvi, Kari; Oksanen, Lauri; Rikkinen, Kari

    2001-10-01

    Standardization of 3rd Generation (3G) mobile communication systems has produced the first specification releases and the commercial deployment of the 3G systems has started. Whereas 1G and 2G focused on efficiently providing voice services, in 3G a lot of attention has been devoted to solutions that support both Circuit Switched (CS) and Packet Switched (PS) communication. That has called for very flexible air interface and network solutions. 3G will continue to evolve and there are already on-going standardization activities that will, for example, boost the peak data rates up to 5-10 Mbps and improve spectral efficiency by 2-4 times. In the future, 3G evolution will be going towards 10/100 Mbps peak data rates in wide/local are coverage, respectively. This will take place partly because of technical improvements of 3G radio interface solutions, but also due to network evolution which will allow the integration other radio access methods like radio LANs into the 3G system. In longer term the 3G network evolution will be going towards ALL-IP networks. As 3G evolution seems to be going towards 10 Mbps/100 Mbps peak data rates and ALL-IP networks any beyond 3G air interface or network solution should be clearly better in order to justify its technical and commercial feasibility. Given the long evolution time of 3G and integration of other radio access schemes with 3G radio we may not even see a new, complete beyond 3G system being developed. Maybe we will just witness the emergence of a new, more advanced radio access solution which will then be connected to the evolving 3G network. As 3G evolution will continue for several years to come the research targets for any beyond 3G solutions must be set very high. When it comes to air interface, we should aim at 100 Mbps peak data rates for wide area access with high mobility, and at 1 Gbps for local area access with low mobility. Regarding possible commercial launches of any beyond 3G systems or solutions they could then take place around year 2010 or even later.

  9. Procedures of grasp92 code to calculate accurate Dirac-Coulomb energy for the ground sate of helium atom

    International Nuclear Information System (INIS)

    Utsumi, Takayuki; Sasaki, Akira

    2000-02-01

    The procedures of grasp92 code to calculate accurate (relative error nearly equal 10 -7 ) eigenvalue for the ground sate of helium atom of the Dirac-Coulomb Hamiltonian are presented. The grasp92 code, based on the multi-configuration Dirac-Fock method, is widely used to calculate the atomic properties. However, the main part of the accurate calculations, extended optimal level calculation (EOL), suffer frequently numerical instabilities due to the lack of the confident procedures. The purpose of this report is to illustrate the guideline for stable EOL calculations by calculating the most fundamental atomic system, i.e. the ground sate of helium atom ls 2 1 S 2 . This procedure could be extended for the high-precise eigenfunction calculation of more complex atomic systems, for example highly ionized atoms and high-Z atoms. (author)

  10. Limited Fine Motor and Grasping Skills in Six-month-old Infants at High Risk for Autism

    Science.gov (United States)

    Libertus, Klaus; Sheperd, Kelly A.; Ross, Samuel W.; Landa, Rebecca J.

    2014-01-01

    Atypical motor behaviors are common among children with Autism Spectrum Disorders (ASD). However, little is known about onset and functional implications of differences in early motor development among infants later diagnosed with ASD. Two prospective experiments were conducted to investigate motor skills among six-month-olds at increased risk (high-risk) for ASD (N1 = 129; N2 = 46). Infants were assessed using the Mullen Scales of Early Learning (MSEL) and during toy play. Across both experiments, high-risk infants exhibited less mature object manipulation in a highly structured (MSEL) context and reduced grasping activity in an unstructured (free play) context than infants with no family history of ASD. Longitudinal assessments suggest that between six and ten months, grasping activity increases in high-risk infants. PMID:24978128

  11. Limited fine motor and grasping skills in 6-month-old infants at high risk for autism.

    Science.gov (United States)

    Libertus, Klaus; Sheperd, Kelly A; Ross, Samuel W; Landa, Rebecca J

    2014-01-01

    Atypical motor behaviors are common among children with autism spectrum disorders (ASD). However, little is known about onset and functional implications of differences in early motor development among infants later diagnosed with ASD. Two prospective experiments were conducted to investigate motor skills among 6-month-olds at increased risk (high risk) for ASD (N1  = 129; N2  = 46). Infants were assessed using the Mullen Scales of Early Learning (MSEL) and during toy play. Across both experiments, high-risk infants exhibited less mature object manipulation in a highly structured (MSEL) context and reduced grasping activity in an unstructured (free-play) context than infants with no family history of ASD. Longitudinal assessments suggest that between 6 and 10 months, grasping activity increases in high-risk infants. © 2014 The Authors. Child Development © 2014 Society for Research in Child Development, Inc.

  12. Spontaneous in-flight accommodation of hand orientation to unseen grasp targets: A case of action blindsight.

    Science.gov (United States)

    Prentiss, Emily K; Schneider, Colleen L; Williams, Zoë R; Sahin, Bogachan; Mahon, Bradford Z

    2018-03-15

    The division of labour between the dorsal and ventral visual pathways is well established. The ventral stream supports object identification, while the dorsal stream supports online processing of visual information in the service of visually guided actions. Here, we report a case of an individual with a right inferior quadrantanopia who exhibited accurate spontaneous rotation of his wrist when grasping a target object in his blind visual field. His accurate wrist orientation was observed despite the fact that he exhibited no sensitivity to the orientation of the handle in a perceptual matching task. These findings indicate that non-geniculostriate visual pathways process basic volumetric information relevant to grasping, and reinforce the observation that phenomenal awareness is not necessary for an object's volumetric properties to influence visuomotor performance.

  13. Fundamental concepts on energy

    International Nuclear Information System (INIS)

    Rodriguez, M.H.

    1998-01-01

    The fundamental concepts on energy and the different forms in which it is manifested are presented. Since it is possible to transform energy in a way to other, the laws that govern these transformations are discussed. The energy transformation processes are an essential compound in the capacity humanizes to survive and be developed. The energy use brings important economic aspects, technical and political. Because this, any decision to administer energy system will be key for our future life

  14. Systemizing the Pedagogic Concepts

    Directory of Open Access Journals (Sweden)

    G. N. Serikov

    2013-01-01

    Full Text Available The paper emphasizes the necessity of systemizing the pedagogic concepts to complement the pluralism principle dominating in pedagogy over the recent years. The author recommends the person oriented systematic synergetic methodology combining various research data into a holistic scientific approach. The paper regards education as the core pedagogic concept - including training, upbringing, self-education, their respective subcomponents, and generated personal resource. The elements of personal resource combine the acquired knowledge, skills and values, developed subjective attitudes and individual health data. The key pedagogic terms describing the educational process are represented by a three-level system; the first level involves the educational form concepts, the second – generated personal resource, the third – summarized notion system combining the previous levels and reflecting their binary relations. The given construct systemizes the pedagogic conceptual apparatus and clarifies the theoretical notion of personal education. 

  15. Renyi information gain on quantum key

    International Nuclear Information System (INIS)

    Brandt, Howard E

    2007-01-01

    The concept of maximum Renyi information gain from quantum key is important in eavesdropping and security analyses of quantum key distribution. It is particularly useful in the design optimization of eavesdropping probes. The present work reviews the quantitative measure of Renyi information gain, its optimization, and application to the design of eavesdropping probes in which single-photon probe states become optimally entangled with the signal states on their way between the legitimate transmitter and receiver

  16. One digit interruption: the altered force patterns during functionally cylindrical grasping tasks in patients with trigger digits.

    Directory of Open Access Journals (Sweden)

    Po-Tsun Chen

    Full Text Available Most trigger digit (TD patients complain that they have problems using their hand in daily or occupational tasks due to single or multiple digits being affected. Unfortunately, clinicians do not know much about how this disease affects the subtle force coordination among digits during manipulation. Thus, this study examined the differences in force patterns during cylindrical grasp between TD and healthy subjects. Forty-two TD patients with single digit involvement were included and sorted into four groups based on the involved digits, including thumb, index, middle and ring fingers. Twelve healthy subjects volunteered as healthy controls. Two testing tasks, holding and drinking, were performed by natural grasping with minimal forces. The relations between the force of the thumb and each finger were examined by Pearson correlation coefficients. The force amount and contribution of each digit were compared between healthy controls and each TD group by the independent t test. The results showed all TD groups demonstrated altered correlation patterns of the thumb relative to each finger. Larger forces and higher contributions of the index finger were found during holding by patients with index finger involved, and also during drinking by patients with affected thumb and with affected middle finger. Although no triggering symptom occurred during grasping, the patients showed altered force patterns which may be related to the role of the affected digit in natural grasping function. In conclusion, even if only one digit was affected, the subtle force coordination of all the digits was altered during simple tasks among the TD patients. This study provides the information for the future studies to further comprehend the possible injuries secondary to the altered finger coordination and also to adopt suitable treatment strategies.

  17. One digit interruption: the altered force patterns during functionally cylindrical grasping tasks in patients with trigger digits.

    Science.gov (United States)

    Chen, Po-Tsun; Lin, Chien-Ju; Jou, I-Ming; Chieh, Hsiao-Feng; Su, Fong-Chin; Kuo, Li-Chieh

    2013-01-01

    Most trigger digit (TD) patients complain that they have problems using their hand in daily or occupational tasks due to single or multiple digits being affected. Unfortunately, clinicians do not know much about how this disease affects the subtle force coordination among digits during manipulation. Thus, this study examined the differences in force patterns during cylindrical grasp between TD and healthy subjects. Forty-two TD patients with single digit involvement were included and sorted into four groups based on the involved digits, including thumb, index, middle and ring fingers. Twelve healthy subjects volunteered as healthy controls. Two testing tasks, holding and drinking, were performed by natural grasping with minimal forces. The relations between the force of the thumb and each finger were examined by Pearson correlation coefficients. The force amount and contribution of each digit were compared between healthy controls and each TD group by the independent t test. The results showed all TD groups demonstrated altered correlation patterns of the thumb relative to each finger. Larger forces and higher contributions of the index finger were found during holding by patients with index finger involved, and also during drinking by patients with affected thumb and with affected middle finger. Although no triggering symptom occurred during grasping, the patients showed altered force patterns which may be related to the role of the affected digit in natural grasping function. In conclusion, even if only one digit was affected, the subtle force coordination of all the digits was altered during simple tasks among the TD patients. This study provides the information for the future studies to further comprehend the possible injuries secondary to the altered finger coordination and also to adopt suitable treatment strategies.

  18. Posture does not matter! Paw usage and grasping paw preference in a small-bodied rooting quadrupedal mammal.

    Science.gov (United States)

    Joly, Marine; Scheumann, Marina; Zimmermann, Elke

    2012-01-01

    Recent results in birds, marsupials, rodents and nonhuman primates suggest that phylogeny and ecological factors such as body size, diet and postural habit of a species influence limb usage and the direction and strength of limb laterality. To examine to which extent these findings can be generalised to small-bodied rooting quadrupedal mammals, we studied trees shrews (Tupaia belangeri). We established a behavioural test battery for examining paw usage comparable to small-bodied primates and tested 36 Tupaia belangeri. We studied paw usage in a natural foraging situation (simple food grasping task) and measured the influence of varying postural demands (triped, biped, cling, sit) on paw preferences by applying a forced-food grasping task similar to other small-bodied primates. Our findings suggest that rooting tree shrews prefer mouth over paw usage to catch food in a natural foraging situation. Moreover, we demonstrated that despite differences in postural demand, tree shrews show a strong and consistent individual paw preference for grasping across different tasks, but no paw preference at a population level. Tree shrews showed less paw usage than small-bodied quadrupedal and arboreal primates, but the same paw preference. Our results confirm that individual paw preferences remain constant irrespective of postural demand in some small-bodied quadrupedal non primate and primate mammals which do not require fine motoric control for manipulating food items. Our findings suggest that the lack of paw/hand preference for grasping food at a population level is a universal pattern among those species and that the influence of postural demand on manual lateralisation in quadrupeds may have evolved in large-bodied species specialised in fine manipulations of food items.

  19. Posture does not matter! Paw usage and grasping paw preference in a small-bodied rooting quadrupedal mammal.

    Directory of Open Access Journals (Sweden)

    Marine Joly

    Full Text Available BACKGROUND: Recent results in birds, marsupials, rodents and nonhuman primates suggest that phylogeny and ecological factors such as body size, diet and postural habit of a species influence limb usage and the direction and strength of limb laterality. To examine to which extent these findings can be generalised to small-bodied rooting quadrupedal mammals, we studied trees shrews (Tupaia belangeri. METHODOLOGY/PRINCIPAL FINDINGS: We established a behavioural test battery for examining paw usage comparable to small-bodied primates and tested 36 Tupaia belangeri. We studied paw usage in a natural foraging situation (simple food grasping task and measured the influence of varying postural demands (triped, biped, cling, sit on paw preferences by applying a forced-food grasping task similar to other small-bodied primates. Our findings suggest that rooting tree shrews prefer mouth over paw usage to catch food in a natural foraging situation. Moreover, we demonstrated that despite differences in postural demand, tree shrews show a strong and consistent individual paw preference for grasping across different tasks, but no paw preference at a population level. CONCLUSIONS/SIGNIFICANCE: Tree shrews showed less paw usage than small-bodied quadrupedal and arboreal primates, but the same paw preference. Our results confirm that individual paw preferences remain constant irrespective of postural demand in some small-bodied quadrupedal non primate and primate mammals which do not require fine motoric control for manipulating food items. Our findings suggest that the lack of paw/hand preference for grasping food at a population level is a universal pattern among those species and that the influence of postural demand on manual lateralisation in quadrupeds may have evolved in large-bodied species specialised in fine manipulations of food items.

  20. Quantum dense key distribution

    International Nuclear Information System (INIS)

    Degiovanni, I.P.; Ruo Berchera, I.; Castelletto, S.; Rastello, M.L.; Bovino, F.A.; Colla, A.M.; Castagnoli, G.

    2004-01-01

    This paper proposes a protocol for quantum dense key distribution. This protocol embeds the benefits of a quantum dense coding and a quantum key distribution and is able to generate shared secret keys four times more efficiently than the Bennet-Brassard 1984 protocol. We hereinafter prove the security of this scheme against individual eavesdropping attacks, and we present preliminary experimental results, showing its feasibility