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Sample records for dynamic object representations

  1. Dynamic updating of hippocampal object representations reflects new conceptual knowledge.

    Science.gov (United States)

    Mack, Michael L; Love, Bradley C; Preston, Alison R

    2016-11-15

    Concepts organize the relationship among individual stimuli or events by highlighting shared features. Often, new goals require updating conceptual knowledge to reflect relationships based on different goal-relevant features. Here, our aim is to determine how hippocampal (HPC) object representations are organized and updated to reflect changing conceptual knowledge. Participants learned two classification tasks in which successful learning required attention to different stimulus features, thus providing a means to index how representations of individual stimuli are reorganized according to changing task goals. We used a computational learning model to capture how people attended to goal-relevant features and organized object representations based on those features during learning. Using representational similarity analyses of functional magnetic resonance imaging data, we demonstrate that neural representations in left anterior HPC correspond with model predictions of concept organization. Moreover, we show that during early learning, when concept updating is most consequential, HPC is functionally coupled with prefrontal regions. Based on these findings, we propose that when task goals change, object representations in HPC can be organized in new ways, resulting in updated concepts that highlight the features most critical to the new goal.

  2. Dynamical issues in interactive representation of physical objects

    CERN Document Server

    Florens, Jean-Loup; Urma, Daniela

    2010-01-01

    The quality of a simulator equipped with a haptic interface is given by the dynamical properties of its components: haptic interface, simulator and control system. Some application areas of such kind of simulator like musical synthesis, animation or more general, instrumental art have specific requirements as for the "haptic rendering" of small movements that go beyond the usual haptic interfaces allow. Object properties variability and different situations of object combination represent important aspects of such type of application which makes that the user can be interested as much in the restitution of certain global properties of an entire object domain as in the restitution of properties that are specific to an isolate object. In the traditional approaches, the usual criteria are founded on the paradigm of transparency and are related to the impedance error introduced by the technical aspects of the system. As a general aim, rather than to minimize these effects, we look to characterize them by physical...

  3. A Representational Similarity Analysis of the Dynamics of Object Processing Using Single-Trial EEG Classification.

    Directory of Open Access Journals (Sweden)

    Blair Kaneshiro

    Full Text Available The recognition of object categories is effortlessly accomplished in everyday life, yet its neural underpinnings remain not fully understood. In this electroencephalography (EEG study, we used single-trial classification to perform a Representational Similarity Analysis (RSA of categorical representation of objects in human visual cortex. Brain responses were recorded while participants viewed a set of 72 photographs of objects with a planned category structure. The Representational Dissimilarity Matrix (RDM used for RSA was derived from confusions of a linear classifier operating on single EEG trials. In contrast to past studies, which used pairwise correlation or classification to derive the RDM, we used confusion matrices from multi-class classifications, which provided novel self-similarity measures that were used to derive the overall size of the representational space. We additionally performed classifications on subsets of the brain response in order to identify spatial and temporal EEG components that best discriminated object categories and exemplars. Results from category-level classifications revealed that brain responses to images of human faces formed the most distinct category, while responses to images from the two inanimate categories formed a single category cluster. Exemplar-level classifications produced a broadly similar category structure, as well as sub-clusters corresponding to natural language categories. Spatiotemporal components of the brain response that differentiated exemplars within a category were found to differ from those implicated in differentiating between categories. Our results show that a classification approach can be successfully applied to single-trial scalp-recorded EEG to recover fine-grained object category structure, as well as to identify interpretable spatiotemporal components underlying object processing. Finally, object category can be decoded from purely temporal information recorded at single

  4. Dynamic object representations in infants with and without fragile X syndrome

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    Faraz Farzin

    2010-03-01

    Full Text Available Our visual world is dynamic in nature. The ability to encode, mentally represent, and track an object’s identity as it moves across time and space is critical for integrating and maintaining a complete and coherent view of the world. Here we investigated dynamic object processing in typically developing (TD infants and infants with fragile X syndrome (FXS, a single-gene disorder associated with deficits in dorsal stream functioning. We used the violation of expectation method to assess infants’ visual response to expected versus unexpected outcomes following a brief dynamic (dorsal stream or static (ventral stream occlusion event. Consistent with previous reports of deficits in dorsal stream-mediated functioning in individuals with this disorder, these results reveal that, compared to mental age-matched TD infants, infants with FXS could maintain the identity of static, but not dynamic, object information during occlusion. These findings are the first to experimentally evaluate visual object processing skills in infants with FXS, and further support the hypothesis of dorsal stream difficulties in infants with this developmental disorder.

  5. Connecting Dynamic Representations of Simple Mathematical Objects with the Construction and Exploration of Conic Sections

    Science.gov (United States)

    Santos-Trigo, Manuel; Espinosa-Perez, Hugo; Reyes-Rodriguez, Aaron

    2008-01-01

    Different technological artefacts may offer distinct opportunities for students to develop resources and strategies to formulate, comprehend and solve mathematical problems. In particular, the use of dynamic software becomes relevant to assemble geometric configurations that may help students reconstruct and examine mathematical relationships. In…

  6. Connecting Dynamic Representations of Simple Mathematical Objects with the Construction and Exploration of Conic Sections

    Science.gov (United States)

    Santos-Trigo, Manuel; Espinosa-Perez, Hugo; Reyes-Rodriguez, Aaron

    2008-01-01

    Different technological artefacts may offer distinct opportunities for students to develop resources and strategies to formulate, comprehend and solve mathematical problems. In particular, the use of dynamic software becomes relevant to assemble geometric configurations that may help students reconstruct and examine mathematical relationships. In…

  7. Parts, Cavities, and Object Representation in Infancy

    Science.gov (United States)

    Hayden, Angela; Bhatt, Ramesh S.; Kangas, Ashley; Zieber, Nicole

    2011-01-01

    Part representation is not only critical to object perception but also plays a key role in a number of basic visual cognition functions, such as figure-ground segregation, allocation of attention, and memory for shapes. Yet, virtually nothing is known about the development of part representation. If parts are fundamental components of object shape…

  8. OBJECT-ORIENTED DATABASE REPRESENTATION THORUGH UML

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    Dr. Vipin Saxena,

    2011-01-01

    Full Text Available Due to the lack of database representation through a well-known object oriented modeling language i.e. Unified Modeling Language (UML, the present work is an attempt to represent the database through UML. In the paper, a case study of Life Insurance Corporation of India is considered to represent the databases of different ongoing policies in the form of object orientation. This will enhance the functioning of the developed software designed on the basis of presented approach. UML Class and Sequence diagrams are designed and then implemented through the SQL Server.

  9. Orienting Attention to Sound Object Representations Attenuates Change Deafness

    Science.gov (United States)

    Backer, Kristina C.; Alain, Claude

    2012-01-01

    According to the object-based account of attention, multiple objects coexist in short-term memory (STM), and we can selectively attend to a particular object of interest. Although there is evidence that attention can be directed to visual object representations, the assumption that attention can be oriented to sound object representations has yet…

  10. An Axiomatic Representation of System Dynamics

    CERN Document Server

    Baianu, I

    2004-01-01

    An axiomatic representation of system dynamics is introduced in terms of categories, functors, organismal supercategories, limits and colimits of diagrams. Specific examples are considered in Complex Systems Biology, such as ribosome biogenesis and Hormonal Control in human subjects. "Fuzzy" Relational Structures are also proposed for flexible representations of biological system dynamics and organization.

  11. Three-dimensional object representation by array grammars

    Science.gov (United States)

    Wang, Patrick S. P.

    1991-02-01

    A new approach for representing 3-d objects by 3-d array grammar is introduced. The concept of universal array grammar is proposed for 3-d object representation. it uses parallelism for pattern generation. Many interesting 3-d objecis can indeed he represented by this universal 3-d array grammar which paves a ground for 3-d object recognition. description and understanding. Keywords: 3-d array grammars. universal array grammars pattern generation. object representation parallel generation I.

  12. Visuo-haptic multisensory object recognition, categorization, and representation

    Science.gov (United States)

    Lacey, Simon; Sathian, K.

    2014-01-01

    Visual and haptic unisensory object processing show many similarities in terms of categorization, recognition, and representation. In this review, we discuss how these similarities contribute to multisensory object processing. In particular, we show that similar unisensory visual and haptic representations lead to a shared multisensory representation underlying both cross-modal object recognition and view-independence. This shared representation suggests a common neural substrate and we review several candidate brain regions, previously thought to be specialized for aspects of visual processing, that are now known also to be involved in analogous haptic tasks. Finally, we lay out the evidence for a model of multisensory object recognition in which top-down and bottom-up pathways to the object-selective lateral occipital complex are modulated by object familiarity and individual differences in object and spatial imagery. PMID:25101014

  13. Representation, Analysis and Visualization of Moving Objects (Dagstuhl Seminar 12512)

    OpenAIRE

    Gudmundsson, Joachim; Laube, Patrick; Van Loon, Emiel

    2013-01-01

    From December 16 to December 21, 2012, the Dagstuhl Seminar 12512 "Representation, Analysis and Visualization of Moving Objects" was held in Schloss Dagstuhl -- Leibniz Center for Informatics. The major goal of this seminar was to bring together the diverse and fast growing, research community that is involved in developing better computational techniques for spatio-temporal object representation, data mining, and visualization of moving object data. The participants included experts from fie...

  14. 10491 Abstracts Collection -- Representation, Analysis and Visualization of Moving Objects

    OpenAIRE

    Sack, Jörg-Rüdiger; Speckmann, Bettina; Van Loon, Emiel; Weibel, Robert

    2011-01-01

    From December 5 to December 10, 2010, the Dagstuhl Seminar 10491 ``Representation, Analysis and Visualization of Moving Objects'' was held in Schloss Dagstuhl~--~Leibniz Center for Informatics. The major goal of this seminar has been to bring together the diverse and fast growing, research community that is involved in developing better computational techniques for spatio-temporal object representation, data mining, and visualization massive amounts of moving object data. ...

  15. Dimensionality of object representations in monkey inferotemporal cortex.

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    Lehky, Sidney R; Kiani, Roozbeh; Esteky, Hossein; Tanaka, Keiji

    2014-10-01

    We have calculated the intrinsic dimensionality of visual object representations in anterior inferotemporal (AIT) cortex, based on responses of a large sample of cells stimulated with photographs of diverse objects. Because dimensionality was dependent on data set size, we determined asymptotic dimensionality as both the number of neurons and number of stimulus image approached infinity. Our final dimensionality estimate was 93 (SD: ± 11), indicating that there is basis set of approximately 100 independent features that characterize the dimensions of neural object space. We believe this is the first estimate of the dimensionality of neural visual representations based on single-cell neurophysiological data. The dimensionality of AIT object representations was much lower than the dimensionality of the stimuli. We suggest that there may be a gradual reduction in the dimensionality of object representations in neural populations going from retina to inferotemporal cortex as receptive fields become increasingly complex.

  16. An object-based methodology for knowledge representation in SGML

    Energy Technology Data Exchange (ETDEWEB)

    Kelsey, R.L. [Los Alamos National Lab., NM (United States)|New Mexico State Univ., Las Cruces, NM (United States); Hartley, R.T. [New Mexico State Univ., Las Cruces, NM (United States); Webster, R.B. [Los Alamos National Lab., NM (United States)

    1997-11-01

    An object-based methodology for knowledge representation and its Standard Generalized Markup Language (SGML) implementation is presented. The methodology includes class, perspective domain, and event constructs for representing knowledge within an object paradigm. The perspective construct allows for representation of knowledge from multiple and varying viewpoints. The event construct allows actual use of knowledge to be represented. The SGML implementation of the methodology facilitates usability, structured, yet flexible knowledge design, and sharing and reuse of knowledge class libraries.

  17. Chain Homotopies for Object Topological Representations

    CERN Document Server

    Gonzalez-Diaz, Rocio; MEdrano, Belen; Real, Pedro; 10.1016/j.dam.2008.05.029

    2011-01-01

    This paper presents a set of tools to compute topological information of simplicial complexes, tools that are applicable to extract topological information from digital pictures. A simplicial complex is encoded in a (non-unique) algebraic-topological format called AM-model. An AM-model for a given object K is determined by a concrete chain homotopy and it provides, in particular, integer (co)homology generators of K and representative (co)cycles of these generators. An algorithm for computing an AM-model and the cohomological invariant HB1 (derived from the rank of the cohomology ring) with integer coefficients for a finite simplicial complex in any dimension is designed here. A concept of generators which are "nicely" representative cycles is also presented. Moreover, we extend the definition of AM-models to 3D binary digital images and we design algorithms to update the AM-model information after voxel set operations (union, intersection, difference and inverse).

  18. Dynamic imagery in children's representations of number

    Science.gov (United States)

    Thomas, Noel; Mulligan, Joanne

    1995-04-01

    An exploratory study of 77 high ability Grade 5 and 6 children investigated links between their understanding of the numeration system and their representations of the counting sequence 1-100. Analysis of children's explanations, and pictorial and notational recordings of the numbers 1-100 revealed three dimensions of external representation—pictorial, ikonic, or notational characteristics—thus providing evidence of creative structural development of the number system, and evidence for the static or dynamic nature of the internal representation. Our observations indicated that children used a wide variety of internal images of which about 30% were dynamic internal representations. Children with a high level of understanding of the numeration system showed evidence of both structure and dynamic imagery in their representations.

  19. The representational dynamics of remembered projectile locations.

    Science.gov (United States)

    De Sá Teixeira, Nuno Alexandre; Hecht, Heiko; Oliveira, Armando Mónica

    2013-12-01

    When people are instructed to locate the vanishing location of a moving target, systematic errors forward in the direction of motion (M-displacement) and downward in the direction of gravity (O-displacement) are found. These phenomena came to be linked with the notion that physical invariants are embedded in the dynamic representations generated by the perceptual system. We explore the nature of these invariants that determine the representational mechanics of projectiles. By manipulating the retention intervals between the target's disappearance and the participant's responses, while measuring both M- and O-displacements, we were able to uncover a representational analogue of the trajectory of a projectile. The outcomes of three experiments revealed that the shape of this trajectory is discontinuous. Although the horizontal component of such trajectory can be accounted for by perceptual and oculomotor factors, its vertical component cannot. Taken together, the outcomes support an internalization of gravity in the visual representation of projectiles.

  20. Dynamic mental representations in language comprehension.

    Science.gov (United States)

    Qu, Chen; Luo, Yue-Jia; Mo, Lei

    2009-06-01

    Previous research has suggested that language comprehension routinely involves dynamic mental representations. Mental representations of temporal information about successive events stored in memory were investigated. Three experiments were conducted using a sentence-probe-recognition task in which the sentence events and the probe events were designed to reflect either a chronological time orientation or a reversed time orientation. The implicit time shift between events also was manipulated. Chronological events were more accessible than the reversed-time events, even for events involving a scenario shift. However, when the sentence events and the probe events differed by level within a hierarchical structure, the effect of temporal orientation disappeared. The results suggest that readers continue to track mentally an event's temporal structure and anticipate the upcoming event in a dynamic representation until another event emerges on a different level within a hierarchical structure.

  1. Social Representations as Dynamic Social Impact.

    Science.gov (United States)

    Huguet, Pascal; Latane, Bibb

    1996-01-01

    Describes Social Representation Theory (SRT), an important and controversial development in European social constructivism. Argues that, although SRT and Dynamic Social Impact Theory (DSIT) come from different research traditions, they are complementary. Maintains that DSIT goes further in providing a clear mechanism for how dialog creates…

  2. Automatic moving object extraction toward compact video representation

    Science.gov (United States)

    Fan, Jianping; Fujita, Gen; Furuie, Makoto; Onoye, Takao; Shirakawa, Isao; Wu, Lide

    2000-02-01

    An automatic object-oriented video segmentation and representation algorithm is proposed, where the local variance contrast and the frame differences contrast are jointly exploited for meaningful moving object extinction because these two visual features can indicate the spatial homogeneity of the gray levels and the temporal coherence of the motion fields efficiently. The 2D entropic thresholding technique and the watershed transformation method are further developed to determine the global feature thresholds adaptively according to the variation of the video components. The obtained video components are first represented by a group of 4 X 4 blocks coarsely, and then the meaningful moving objects are generated by an iterative region-merging procedure according to the spatiotemporal similarity measure. The temporal tracking procedure is further proposed to obtain more semantic moving objects among frames. Therefore, the proposed automatic moving object extraction algorithm can detect the appearance of new objects as well as the disappearance of existing objects efficiently because the correspondence of the video objects among frames is also established. Moreover, an object- oriented video representation and indexing approach is suggested, where both the operation of the camera (i.e., change of the viewpoint) and the birth or death of the individual objects are exploited to detect the breakpoints of the video data and to select the key frames adaptively.

  3. OBJECTIVITY REQUIREMENT FOR FLUID DYNAMICS

    Institute of Scientific and Technical Information of China (English)

    邹文楠

    2003-01-01

    A new flow theory is established through the objectivity requirement on the fluid dynamics. It was known that inhomogeneous fluid motion gave rise to viscous force while the selection of observers on different space-time points would change such an inhomogeneous character. Therefore, when the viscous force was considered as an objective existence foreign to the selection of observers, the form invariances of viscous force and momentum equation under local rotation transformation required a new dynamic field,namely the vortex field to be introduced. Then the dynamical equations of all flow fields were obtained through constructing the Lagrangian density of fluid system and using the variational approach of energy.

  4. Teaching object concepts for XML-based representations.

    Energy Technology Data Exchange (ETDEWEB)

    Kelsey, R. L. (Robert L.)

    2002-01-01

    Students learned about object-oriented design concepts and knowledge representation through the use of a set of toy blocks. The blocks represented a limited and focused domain of knowledge and one that was physical and tangible. The blocks helped the students to better visualize, communicate, and understand the domain of knowledge as well as how to perform object decomposition. The blocks were further abstracted to an engineering design kit for water park design. This helped the students to work on techniques for abstraction and conceptualization. It also led the project from tangible exercises into software and programming exercises. Students employed XML to create object-based knowledge representations and Java to use the represented knowledge. The students developed and implemented software allowing a lay user to design and create their own water slide and then to take a simulated ride on their slide.

  5. USING MORPHLET-BASED IMAGE REPRESENTATION FOR OBJECT DETECTION

    Directory of Open Access Journals (Sweden)

    V. S. Gorbatsevich

    2016-06-01

    Full Text Available In this paper, we propose an original method for objects detection based on a special tree-structured image representation – the trees of morphlets. The method provides robust detection of various types of objects in an image without employing a machine learning procedure. Along with a bounding box creation on a detection step, the method makes pre-segmentation, which can be further used for recognition purposes. Another important feature of the proposed approach is that there are no needs to use a running window as well as a features pyramid in order to detect the objects of different sizes.

  6. Classification problems in object-based representation systems

    OpenAIRE

    Napoli, Amedeo

    1999-01-01

    Colloque avec actes et comité de lecture.; Classification is a process that consists in two dual operations: generating a set of classes and then classifying given objects into the created classes. The class generation may be understood as a learning process and object classification as a problem-solving process. The goal of this position paper is to introduce and to make precise the notion of a classification problem in object-based representation systems, e.g. a query against a class hierar...

  7. Human object-similarity judgments reflect and transcend the primate-IT object representation

    Directory of Open Access Journals (Sweden)

    Marieke eMur

    2013-03-01

    Full Text Available Primate inferior temporal (IT cortex is thought to contain a high-level representation of objects at the interface between vision and semantics. This suggests that the perceived similarity of real-world objects might be predicted from the IT representation. Here we show that objects that elicit similar activity patterns in human IT tend to be judged as similar by humans. The IT representation explained the human judgments better than early visual cortex, other ventral stream regions, and a range of computational models. Human similarity judgments exhibited category clusters that reflected several categorical divisions that are prevalent in the IT representation of both human and monkey, including the animate/inanimate and the face/body division. Human judgments also reflected the within-category representation of IT. However, the judgments transcended the IT representation in that they introduced additional categorical divisions. In particular, human judgments emphasized human-related additional divisions between human and nonhuman animals and between man-made and natural objects. Human IT was more similar to monkey IT than to human judgments. One interpretation is that IT has evolved visual feature detectors that distinguish between animates and inanimates and between faces and bodies because these divisions are fundamental to survival and reproduction for all primate species, and that other brain systems serve to more flexibly introduce species-dependent and evolutionarily more recent divisions.

  8. Human Object-Similarity Judgments Reflect and Transcend the Primate-IT Object Representation.

    Science.gov (United States)

    Mur, Marieke; Meys, Mirjam; Bodurka, Jerzy; Goebel, Rainer; Bandettini, Peter A; Kriegeskorte, Nikolaus

    2013-01-01

    Primate inferior temporal (IT) cortex is thought to contain a high-level representation of objects at the interface between vision and semantics. This suggests that the perceived similarity of real-world objects might be predicted from the IT representation. Here we show that objects that elicit similar activity patterns in human IT (hIT) tend to be judged as similar by humans. The IT representation explained the human judgments better than early visual cortex, other ventral-stream regions, and a range of computational models. Human similarity judgments exhibited category clusters that reflected several categorical divisions that are prevalent in the IT representation of both human and monkey, including the animate/inanimate and the face/body division. Human judgments also reflected the within-category representation of IT. However, the judgments transcended the IT representation in that they introduced additional categorical divisions. In particular, human judgments emphasized human-related additional divisions between human and non-human animals and between man-made and natural objects. hIT was more similar to monkey IT than to human judgments. One interpretation is that IT has evolved visual-feature detectors that distinguish between animates and inanimates and between faces and bodies because these divisions are fundamental to survival and reproduction for all primate species, and that other brain systems serve to more flexibly introduce species-dependent and evolutionarily more recent divisions.

  9. The dynamics of social representations in a situation of immigration

    Directory of Open Access Journals (Sweden)

    Aicha Belarbi

    2004-10-01

    Full Text Available For the author, globalisation, defined as the internationalisation of exchanges, involves bearing in mind the migration issue in great national and international strategic concerns. Discourses on migration are closely linked with social representations in migratory events. This article constitutes an attempt to focus on the dynamics of social relations in a multicultural situation generated by migration, the objective of which lies in deconstructing the socialrepresentations of the immigrant. With the aim of establishing a theoretical framework for capturing the dynamics of immigrants’ representations and making the instability and fragility of these relations explicit, it presents a brief historical compendium of immigration, before situating the stages of the construction of the social representation, differentiating identity and otherness.

  10. Forms of Memory for Representation of Visual Objects

    Science.gov (United States)

    1991-04-15

    SCHACTER: PERCEPTUAL REPRESENTATION. IMPLICIT MEMORY 545 (i.e., alexia ) and perceptual dysfunctions (i.e., agnosia). Observations from these patient...dissocia- tions to observations concerning patients with acquired reading disorders ( alexia ) and (3) object-processing disorders (agnosia) that provide the... central motivation for the PRS hypothesis, and (4) a summary of some recent research from my laboratory concerning nonverbal implicit memory that

  11. The mathematical representation of physical objects and relativistic Quantum Mechanics

    OpenAIRE

    Romay, Enrique Ordaz

    2004-01-01

    The mathematical representation of the physical objects determines which mathematical branch will be applied during the physical analysis in the systems studied. The difference among non-quantum physics, like classic or relativistic physics, and quantum physics, especially in quantum field theory, is nothing else than the difference between the mathematics that is used on both branches of the physics. A common physical and mathematical origin for the analysis of the different systems brings b...

  12. Characteristics of Haptic Peripersonal Spatial Representation of Object Relations

    Science.gov (United States)

    2016-01-01

    Haptic perception of space is known to show characteristics that are different to actual space. The current study extends on this line of research, investigating whether systematic deviations are also observed in the formation of haptic spatial representations of object-to-object relations. We conducted a haptic spatial reproduction task analogous to the parallelity task with spatial layouts. Three magnets were positioned to form corners of an isosceles triangle and the task of the participant was to reproduce the right angle corner. Weobserved systematic deviations in the reproduction of the right angle triangle. The systematic deviations were not observed when the task was conducted on the mid-sagittal plane. Furthermore, the magnitude of the deviation was decreased when non-informative vision was introduced. These results suggest that there is a deformation in spatial representation of object-to-object relations formed using haptics. However, as no systematic deviation was observed when the task was conducted on the mid-saggital plane, we suggest that the perception of object-to-object relations use a different egocentric reference frame to the perception of orientation. PMID:27462990

  13. Characteristics of Haptic Peripersonal Spatial Representation of Object Relations.

    Directory of Open Access Journals (Sweden)

    Ryo Wako

    Full Text Available Haptic perception of space is known to show characteristics that are different to actual space. The current study extends on this line of research, investigating whether systematic deviations are also observed in the formation of haptic spatial representations of object-to-object relations. We conducted a haptic spatial reproduction task analogous to the parallelity task with spatial layouts. Three magnets were positioned to form corners of an isosceles triangle and the task of the participant was to reproduce the right angle corner. Weobserved systematic deviations in the reproduction of the right angle triangle. The systematic deviations were not observed when the task was conducted on the mid-sagittal plane. Furthermore, the magnitude of the deviation was decreased when non-informative vision was introduced. These results suggest that there is a deformation in spatial representation of object-to-object relations formed using haptics. However, as no systematic deviation was observed when the task was conducted on the mid-saggital plane, we suggest that the perception of object-to-object relations use a different egocentric reference frame to the perception of orientation.

  14. Wavelet representation of the nuclear dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Jouault, B.; Sebille, F.; Mota, V. de la

    1997-12-31

    The study of transport phenomena in nuclear matter is addressed in a new approach named DYWAN, based on the projection methods of statistical physics and on the mathematical theory of wavelets. Strongly compressed representations of the nuclear systems are obtained with an accurate description of the wave functions and of their antisymmetrization. The results of the approach are illustrated for the ground state description as well as for the dissipative dynamics of nuclei at intermediate energies. (K.A.). 52 refs.

  15. Components of Action Representations Evoked when Identifying Manipulable Objects

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    Daniel N Bub

    2015-02-01

    Full Text Available We examined the influence of holding planned hand actions in working memory on the time taken to visually identify objects with handles. Features of the hand actions and position of the object's handle were congruent or incongruent on two dimensions: alignment (left vs. right and orientation (horizontal vs. vertical. When an object was depicted in an upright view, subjects were slower to name it when its handle was congruent with the planned hand actions on one dimension but incongruent on the other, relative to when the object handle and actions were congruent on both or neither dimension. This pattern is consistent with many other experiments demonstrating that a cost occurs when there is partial feature overlap between a planned action and a perceived target. An opposite pattern of results was obtained when the depicted object appeared in a 90-degree rotated view (e.g., a beer mug on its side, suggesting that the functional goal associated with the object (e.g., drinking from an upright beer mug was taken into account during object perception and that this knowledge superseded the influence of the action afforded by the depicted view of the object. These results have implications for the relationship between object perception and action representations, and for the mechanisms that support the identification of rotated objects.

  16. Exploring spatial data representation with dynamic graphics

    Science.gov (United States)

    Dykes, Jason A.

    1997-05-01

    Dynamic mapping capabilities are providing enormous potential for visualizing spatial data. Dynamic maps which exhibit observer-related behaviour are particularly appropriate for exploratory analysis, where multiple, short-term, slightly different, views of a data set, each produced with a specific task or question in mind, are an essential part of the analytical process. This paper and the associated coloured and dynamic illustrations take advantage of World Wide Web (WWW) delivery and the digital medium by using interactive graphics to introduce an approach to dynamic cartography based upon the Tcl/Tk graphical user interface (GUI) builder. Generic ways of programming observer-related behaviour, such as brushing, dynamic re-expression, and dynamic comparison, are outlined and demonstrated to show that specialist dynamic views can be developed rapidly in an open, flexible, and high-level graphic environment. Such an approach provides opportunities to reinforce traditional cartographic and statistical representations of spatial data with dynamic graphics and transient symbolism which give supplementary information about a symbol or statistic on demand. A series of examples from recent work which uses the approach demonstrates ways in which dynamic graphics can be effective in complementing methods of measurement and mapping which are well established in geographic enquiry.

  17. Learning Sparse Representation for Objective Image Retargeting Quality Assessment.

    Science.gov (United States)

    Jiang, Qiuping; Shao, Feng; Lin, Weisi; Jiang, Gangyi

    2017-04-13

    The goal of image retargeting is to adapt source images to target displays with different sizes and aspect ratios. Different retargeting operators create different retargeted images, and a key problem is to evaluate the performance of each retargeting operator. Subjective evaluation is most reliable, but it is cumbersome and labor-consuming, and more importantly, it is hard to be embedded into online optimization systems. This paper focuses on exploring the effectiveness of sparse representation for objective image retargeting quality assessment. The principle idea is to extract distortion sensitive features from one image (e.g., retargeted image) and further investigate how many of these features are preserved or changed in another one (e.g., source image) to measure the perceptual similarity between them. To create a compact and robust feature representation, we learn two overcomplete dictionaries to represent the distortion sensitive features of an image. Features including local geometric structure and global context information are both addressed in the proposed framework. The intrinsic discriminative power of sparse representation is then exploited to measure the similarity between the source and retargeted images. Finally, individual quality scores are fused into an overall quality by a typical regression method. Experimental results on several databases have demonstrated the superiority of the proposed method.

  18. An object-based methodology for knowledge representation

    Energy Technology Data Exchange (ETDEWEB)

    Kelsey, R.L. [Los Alamos National Lab., NM (United States)|New Mexico State Univ., Las Cruces, NM (United States); Hartley, R.T. [New Mexico State Univ., Las Cruces, NM (United States); Webster, R.B. [Los Alamos National Lab., NM (United States)

    1997-11-01

    An object based methodology for knowledge representation is presented. The constructs and notation to the methodology are described and illustrated with examples. The ``blocks world,`` a classic artificial intelligence problem, is used to illustrate some of the features of the methodology including perspectives and events. Representing knowledge with perspectives can enrich the detail of the knowledge and facilitate potential lines of reasoning. Events allow example uses of the knowledge to be represented along with the contained knowledge. Other features include the extensibility and maintainability of knowledge represented in the methodology.

  19. The role of action representations in thematic object relations.

    Directory of Open Access Journals (Sweden)

    Konstantinos eTsagkaridis

    2014-03-01

    Full Text Available Recent studies assessing the role of associative/event-based (thematic and categorical (taxonomic relations in the organization of object representations suggest that thematic relationships may influence the perceived similarity of manipulable artifacts. At the same time, evidence suggests that action knowledge is an important component of manipulable artifact representations. However, the role that action plays in processing thematic relationships between objects is unclear. In this study, we assessed healthy and left hemisphere stroke participants to explore three questions: 1. Do participants favor thematic relations involving action (Th+A, e.g., wine bottle – corkscrew, thematic relationships without action (Th-A, e.g., wine bottle – cheese, or taxonomic relationships (Tax, e.g., wine bottle – water bottle when choosing between them in an association judgment task? 2. Do the underlying constructs of event, action, and categorical relatedness implicitly determine the choices that participants make? 3. Does degraded action knowledge and/or damage to temporo-parietal cortex (a region of the brain associated with action representations reduce the influence of action on the choice task? Experiment 1 showed that explicit ratings of event, action, and categorical relatedness differentially predicted healthy participants’ choices, with action relatedness determining choices between Th+A and Th-A associations above and beyond event and categorical ratings. Experiment 2 focused more specifically on these Th+A vs. Th-A choices and demonstrated that participants with left temporo-parietal lesions, a brain region known to be involved in sensorimotor processing, were less likely than controls, and tended to be less likely than patients with lesions sparing that region, to implicitly use action knowledge in determining their choices. We conclude that action knowledge plays a critical role in processing of thematic relations for manipulable

  20. Hamiltonian dynamics of extended objects

    Energy Technology Data Exchange (ETDEWEB)

    Capovilla, R [Departamento de FIsica, Centro de Investigacion y de Estudios Avanzados del IPN, Apdo Postal 14-740, 07000 Mexico, DF (Mexico); Guven, J [School of Theoretical Physics, Dublin Institute for Advanced Studies, 10 Burlington Road, Dublin 4 (Ireland); Rojas, E [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Apdo Postal 70-543, 04510 Mexico, DF (Mexico)

    2004-12-07

    We consider relativistic extended objects described by a reparametrization-invariant local action that depends on the extrinsic curvature of the worldvolume swept out by the object as it evolves. We provide a Hamiltonian formulation of the dynamics of such higher derivative models which is motivated by the ADM formulation of general relativity. The canonical momenta are identified by looking at boundary behaviour under small deformations of the action; the relationship between the momentum conjugate to the embedding functions and the conserved momentum density is established. The canonical Hamiltonian is constructed explicitly; the constraints on the phase space, both primary and secondary, are identified and the role they play in the theory is described. The multipliers implementing the primary constraints are identified in terms of the ADM lapse and shift variables and Hamilton's equations are shown to be consistent with the Euler-Lagrange equations.

  1. Content-adaptive pyramid representation for 3D object classification

    DEFF Research Database (Denmark)

    Kounalakis, Tsampikos; Boulgouris, Nikolaos; Triantafyllidis, Georgios

    2016-01-01

    In this paper we introduce a novel representation for the classification of 3D images. Unlike most current approaches, our representation is not based on a fixed pyramid but adapts to image content and uses image regions instead of rectangular pyramid scales. Image characteristics, such as depth ...... and color, are used for defining regions within images. Multiple region scales are formed in order to construct the proposed pyramid image representation. The proposed method achieves excellent results in comparison to conventional representations....

  2. The representation of object distance: evidence from neuroimaging and neuropsychology

    Directory of Open Access Journals (Sweden)

    Marian Berryhill

    2009-11-01

    Full Text Available Perceived distance in two-dimensional images relies on monocular distance cues. Here, we examined the representation of perceived object distance using a continuous carry-over adaptation design for fMRI. The task was to look at photographs of objects and make a judgment as to whether or not the item belonged in the kitchen. Importantly, this task was orthogonal to the variable of interest: the object’s perceived distance from the viewer. In Experiment 1, whole brain group analyses identified bilateral clusters in the superior occipital gyrus (approximately area V3/V3A that showed parametric adaptation to relative changes in perceived distance. In Experiment 2, retinotopic analyses confirmed that area V3A/B reflected the greatest magnitude of response to monocular changes in perceived distance. In Experiment 3, we report that the functional activations overlap with the occipito-parietal lesions in a patient with impaired distance perception, showing that the same regions monitor implied (two-dimensional and actual (three-dimensional distance. These data suggest that distance information is automatically processed even when it is task-irrelevant and that this process relies on superior occipital areas in and around area V3A.

  3. Dynamic object-oriented geospatial modeling

    Directory of Open Access Journals (Sweden)

    Tomáš Richta

    2010-02-01

    Full Text Available Published literature about moving objects (MO simplifies the problem to the representation and storage of moving points, moving lines, or moving regions. The main insufficiency of this approach is lack of MO inner structure and dynamics modeling – the autonomy of moving agent. This paper describes basics of the object-oriented geospatial methodology for modeling complex systems consisting of agents, which move within spatial environment. The main idea is that during the agent movement, different kinds of connections with other moving or stationary objects are established or disposed, based on some spatial constraint satisfaction or nonfulfilment respectively. The methodology is constructed with regard to following two main conditions – 1 the inner behavior of agents should be represented by any formalism, e.g.  Petri net, finite state machine, etc., and 2 the spatial characteristic of environment should be supplied by any information system, that is able to store defined set of spatial types, and support defined set of spatial operations. Finally, the methodology is demonstrated on simple simulation model of tram transportation system.

  4. Discriminative object tracking via sparse representation and online dictionary learning.

    Science.gov (United States)

    Xie, Yuan; Zhang, Wensheng; Li, Cuihua; Lin, Shuyang; Qu, Yanyun; Zhang, Yinghua

    2014-04-01

    We propose a robust tracking algorithm based on local sparse coding with discriminative dictionary learning and new keypoint matching schema. This algorithm consists of two parts: the local sparse coding with online updated discriminative dictionary for tracking (SOD part), and the keypoint matching refinement for enhancing the tracking performance (KP part). In the SOD part, the local image patches of the target object and background are represented by their sparse codes using an over-complete discriminative dictionary. Such discriminative dictionary, which encodes the information of both the foreground and the background, may provide more discriminative power. Furthermore, in order to adapt the dictionary to the variation of the foreground and background during the tracking, an online learning method is employed to update the dictionary. The KP part utilizes refined keypoint matching schema to improve the performance of the SOD. With the help of sparse representation and online updated discriminative dictionary, the KP part are more robust than the traditional method to reject the incorrect matches and eliminate the outliers. The proposed method is embedded into a Bayesian inference framework for visual tracking. Experimental results on several challenging video sequences demonstrate the effectiveness and robustness of our approach.

  5. An Axiomatic, Unified Representation of Biosystems and Quantum Dynamics

    CERN Document Server

    Baianu, I

    2004-01-01

    An axiomatic representation of system dynamics is introduced in terms of categories, functors, organismal supercategories, limits and colimits of diagrams. Specific examples are considered in Complex Systems Biology, such as ribosome biogenesis and Hormonal Control in human subjects. "Fuzzy" Relational Structures are also proposed for flexible representations of biological system dynamics and organization.

  6. Age-Related Deficits in Conjunctive Representation of Complex Objects

    Science.gov (United States)

    Scheerer, Nichole; Marrone, Diano F.

    2014-01-01

    Although some evidence is consistent with the notion that distinct cortical systems support memory and perception, mounting evidence supports a representational-hierarchical view of cognition, which posits that distinctions lie in simple feature representations versus more complex conjunctive representations of many stimulus features simultaneously. Thus, typical memory tasks engage different regions from typical perception tasks because they inherently test information on opposing ends of this continuum. Memory deficits are reliably reported with age, but the tasks used to make these conclusions predominantly rely on conjunctive representations. To test the extent to which age-related deficits may be accounted for by perceptual processing, this study investigated discriminations involving conjunctive representations in older adults. Results show that adults aged 50 to 77 are impaired, relative to their younger counterparts, on discriminations requiring feature conjunctions, but not simple feature representations. These findings support recent data showing an agerelated decline in the ability to form conjunctive representations. Furthermore, these data suggest that some ‘mnemonic’ deficits associated with age may in fact be the result of deficits in perception rather than memory. PMID:25308561

  7. Spatiotemporal Dynamics of Cortical Representations during and after Stimulus Presentation

    Directory of Open Access Journals (Sweden)

    Marieke Esther van de Nieuwenhuijzen

    2016-05-01

    Full Text Available Visual perception is a spatiotemporally complex process. In this study, we investigated cortical dynamics during and after stimulus presentation. We observed that visual category information related to the difference between faces and objects became apparent in the occipital lobe after 63 ms. Within the next 110 ms, activation spread out to include the temporal lobe before returning to residing mainly in the occipital lobe again. After stimulus offset, a peak in information was observed, comparable to the peak after stimulus onset. Moreover, similar processes, albeit not identical, seemed to underlie both peaks. Information about the categorical identity of the stimulus remained present until 677 ms after stimulus offset, during which period the stimulus had to be retained in working memory. Activation patterns initially resembled those observed during stimulus presentation. After about 200 ms, however, this representation changed and class-specific activity became more equally distributed over the four lobes. These results show that, although there are common processes underlying stimulus representation both during and after stimulus presentation, these representations change depending on the specific stage of perception and maintenance.

  8. Benchmarks for dynamic multi-objective optimisation

    CSIR Research Space (South Africa)

    Helbig, M

    2013-06-01

    Full Text Available When algorithms solve dynamic multi-objective optimisation problems (DMOOPs), benchmark functions should be used to determine whether the algorithm can overcome specific difficulties that can occur in real-world problems. However, for dynamic multi...

  9. Dynamics of compact object mergers

    Science.gov (United States)

    Bauswein, Andreas

    2017-01-01

    Advanced LIGO's first detection of gravitational waves (GWs) from merging black holes has opened a new window to the Universe. The observation of neutron-star (NS) mergers is imminent and promises far-reaching implications. We will describe the dynamics of NS mergers focusing on the postmerger dynamics. In particular, we will point out the implications for matter ejection from these events. Neutron-rich outflows from NS mergers are invoked to explain the still mysterious origin of heavy elements which are formed through the rapid neutron-capture process. The nuclear decays in these ejecta power electromagnetic counterparts which are potentially observable. We will describe the properties of these transients within a multi-messenger picture including in particular information that can be revealed from simultaneous GW detections.

  10. Decoding information about dynamically occluded objects in visual cortex.

    Science.gov (United States)

    Erlikhman, Gennady; Caplovitz, Gideon P

    2017-02-01

    During dynamic occlusion, an object passes behind an occluding surface and then later reappears. Even when completely occluded from view, such objects are experienced as continuing to exist or persist behind the occluder even though they are no longer visible. The contents and neural basis of this persistent representation remain poorly understood. Questions remain as to whether there is information maintained about the object itself (i.e. its shape or identity) or non-object-specific information such as its position or velocity as it is tracked behind an occluder, as well as which areas of visual cortex represent such information. Recent studies have found that early visual cortex is activated by "invisible" objects during visual imagery and by unstimulated regions along the path of apparent motion, suggesting that some properties of dynamically occluded objects may also be neurally represented in early visual cortex. We applied functional magnetic resonance imaging in human subjects to examine representations within visual cortex during dynamic occlusion. For gradually occluded, but not for instantly disappearing objects, there was an increase in activity in early visual cortex (V1, V2, and V3). This activity was spatially-specific, corresponding to the occluded location in the visual field. However, the activity did not encode enough information about object identity to discriminate between different kinds of occluded objects (circles vs. stars) using MVPA. In contrast, object identity could be decoded in spatially-specific subregions of higher-order, topographically organized areas such as ventral, lateral, and temporal occipital areas (VO, LO, and TO) as well as the functionally defined LOC and hMT+. These results suggest that early visual cortex may only represent the dynamically occluded object's position or motion path, while later visual areas represent object-specific information.

  11. A cluster-based method for marine sensitive object extraction and representation

    Science.gov (United States)

    Xue, Cunjin; Dong, Qing; Qin, Lijuan

    2015-08-01

    Within the context of global change, marine sensitive factors or Marine Essential Climate Variables have been defined by many projects, and their sensitive spatial regions and time phases play significant roles in regional sea-air interactions and better understanding of their dynamic process. In this paper, we propose a cluster-based method for marine sensitive region extraction and representation. This method includes a kernel expansion algorithm for extracting marine sensitive regions, and a field-object triple form, integration of object-oriented and field-based model, for representing marine sensitive objects. Firstly, this method recognizes ENSO-related spatial patterns using empirical orthogonal decomposition of long term marine sensitive factors and correlation analysis with multiple ENSO index. The cluster kernel, defined by statistics of spatial patterns, is initialized to carry out spatial expansion and cluster mergence with spatial neighborhoods recursively, then all the related lattices with similar behavior are merged into marine sensitive regions. After this, the Field-object triple form of is used to represent the marine sensitive objects, both with the discrete object with a precise extend and boundary, and the continuous field with variations dependent on spatial locations. Finally, the marine sensitive objects about sea surface temperature are extracted, represented and analyzed as a case of study, which proves the effectiveness and the efficiency of the proposed method.

  12. The left fusiform gyrus hosts trisensory representations of manipulable objects

    DEFF Research Database (Denmark)

    Kassuba, Tanja; Klinge, Corinna; Hölig, Cordula

    2011-01-01

    During object manipulation the brain integrates the visual, auditory, and haptic experience of an object into a unified percept. Previous brain imaging studies have implicated for instance the dorsal part of the lateral occipital complex in visuo-tactile and the posterior superior temporal sulcus....... In the first experiment, we identified brain regions which were consistently activated by unimodal visual, auditory, and haptic processing of manipulable objects relative to non-object control stimuli presented in the same modality. In the second experiment, we assessed regional brain activations when...... was also consistently activated during multisensory matching of object-related information across all three senses. Taken together, our results suggest that this region is central to the recognition of manipulable objects. A putative role of this FG region is to unify object-specific information provided...

  13. Atypical right hemisphere specialization for object representations in an adolescent with specific language impairment

    Directory of Open Access Journals (Sweden)

    Timothy T. Brown

    2014-02-01

    Full Text Available Individuals with a diagnosis of specific language impairment (SLI show abnormal spoken language occurring alongside normal nonverbal abilities. Behaviorally, people with SLI exhibit diverse profiles of impairment involving phonological, grammatical, syntactic, and semantic aspects of language. In this study, we used a multimodal neuroimaging technique called anatomically constrained magnetoencephalography (aMEG to measure the dynamic functional brain organization of an adolescent with SLI. Using single-subject statistical maps of cortical activity, we compared this patient to a sibling and to a cohort of typically developing subjects during the performance of tasks designed to evoke semantic representations of concrete objects. Localized, real-time patterns of brain activity within the language impaired patient showed marked differences from the typical functional organization, with significant engagement of right hemisphere heteromodal cortical regions generally homotopic to the left hemisphere areas that usually show the greatest activity for such tasks. Functional neuroanatomical differences were evident at early sensoriperceptual processing stages and continued through later cognitive stages, observed specifically at latencies typically associated with semantic encoding operations. Our findings show with real-time temporal specificity evidence for an atypical right hemisphere specialization for the representation of concrete entities, independent of verbal motor demands. More broadly, our results demonstrate the feasibility and potential utility of using aMEG to characterize individual patient differences in the dynamic functional organization of the brain.

  14. Covariant GNS Representation for C*-Dynamical Systems

    CERN Document Server

    Pandiscia, Carlo

    2012-01-01

    We extend the covariant GNS representation of Niculescu, Str\\"oh and Zsid\\'o for C*-dynamical systems with time-evolution of the system (dynamics) a homomorphism of C*-algebras, to any dynamical systems, where the dynamics is an unital completely positive map. We give also an overview on its application to the reversible dilation theory as formulated by B. Kummerer.

  15. Grounded Object and Grasp Representations in a Cognitive Architecture

    DEFF Research Database (Denmark)

    Kraft, Dirk

    for example unknown objects, we need to establish that something is an object (and not, an obstacle). One of the initial steps there is to see if we can manipulate the object. We therefore present work that describes how to achieve physical control over an object. This work uses a feature-action relationship...... 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....... We also explain how the feature-action relationship can be improved through learning from a set of experiences. Once physical control is achieved, we can move the object in such a way that we can gather visual information from different viewpoints. We describe how this information can be integrated...

  16. Dynamic Slicing of Object-Oriented Programs

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Program slice has many applications such as program debugging,testing, maintena n ce, and complexity measurement. A static slice consists of all statements in pro gram P that may effect the value of variable v at some point p, and a dynamic s lice consists only of statements that influence the value of variable occurrence for specific program inputs. In this paper, we concern the problem of dynamic s licing of object-oriented programs which, to our knowledge, has not been addres s ed in the literatures. To solve this problem, we present the dynamic object-ori e nted dependence graph (DODG)which is an arc-classified digraph to explicitly re p resent various dynamic dependence between statement instances for a particular e xecution of an object-oriented program. Based on the DODG, we present a two-ph as e backward algorithm for computing a dynamic slice of an object-oriented program.

  17. Matching categorical object representations in inferior temporal cortex of man and monkey.

    Science.gov (United States)

    Kriegeskorte, Nikolaus; Mur, Marieke; Ruff, Douglas A; Kiani, Roozbeh; Bodurka, Jerzy; Esteky, Hossein; Tanaka, Keiji; Bandettini, Peter A

    2008-12-26

    Inferior temporal (IT) object representations have been intensively studied in monkeys and humans, but representations of the same particular objects have never been compared between the species. Moreover, IT's role in categorization is not well understood. Here, we presented monkeys and humans with the same images of real-world objects and measured the IT response pattern elicited by each image. In order to relate the representations between the species and to computational models, we compare response-pattern dissimilarity matrices. IT response patterns form category clusters, which match between man and monkey. The clusters correspond to animate and inanimate objects; within the animate objects, faces and bodies form subclusters. Within each category, IT distinguishes individual exemplars, and the within-category exemplar similarities also match between the species. Our findings suggest that primate IT across species may host a common code, which combines a categorical and a continuous representation of objects.

  18. Accelerating Dynamic Cardiac MR Imaging Using Structured Sparse Representation

    Directory of Open Access Journals (Sweden)

    Nian Cai

    2013-01-01

    Full Text Available Compressed sensing (CS has produced promising results on dynamic cardiac MR imaging by exploiting the sparsity in image series. In this paper, we propose a new method to improve the CS reconstruction for dynamic cardiac MRI based on the theory of structured sparse representation. The proposed method user the PCA subdictionaries for adaptive sparse representation and suppresses the sparse coding noise to obtain good reconstructions. An accelerated iterative shrinkage algorithm is used to solve the optimization problem and achieve a fast convergence rate. Experimental results demonstrate that the proposed method improves the reconstruction quality of dynamic cardiac cine MRI over the state-of-the-art CS method.

  19. Analysis of the dynamics of reasoning using multiple representations

    NARCIS (Netherlands)

    Jonker, C.M.; Treur, J.

    2008-01-01

    This paper presents a formalisation and analysis method for the dynamics of a reasoning process in which multiple representations play a role. Dynamics of reasoning processes are described by reasoning traces consisting of sequences of reasoning states over time. Reasoning states have a compositiona

  20. Convergent and invariant object representations for sight, sound, and touch.

    Science.gov (United States)

    Man, Kingson; Damasio, Antonio; Meyer, Kaspar; Kaplan, Jonas T

    2015-09-01

    We continuously perceive objects in the world through multiple sensory channels. In this study, we investigated the convergence of information from different sensory streams within the cerebral cortex. We presented volunteers with three common objects via three different modalities-sight, sound, and touch-and used multivariate pattern analysis of functional magnetic resonance imaging data to map the cortical regions containing information about the identity of the objects. We could reliably predict which of the three stimuli a subject had seen, heard, or touched from the pattern of neural activity in the corresponding early sensory cortices. Intramodal classification was also successful in large portions of the cerebral cortex beyond the primary areas, with multiple regions showing convergence of information from two or all three modalities. Using crossmodal classification, we also searched for brain regions that would represent objects in a similar fashion across different modalities of presentation. We trained a classifier to distinguish objects presented in one modality and then tested it on the same objects presented in a different modality. We detected audiovisual invariance in the right temporo-occipital junction, audiotactile invariance in the left postcentral gyrus and parietal operculum, and visuotactile invariance in the right postcentral and supramarginal gyri. Our maps of multisensory convergence and crossmodal generalization reveal the underlying organization of the association cortices, and may be related to the neural basis for mental concepts. © 2015 Wiley Periodicals, Inc.

  1. Repetition Blindness Reveals Differences between the Representations of Manipulable and Nonmanipulable Objects

    Science.gov (United States)

    Harris, Irina M.; Murray, Alexandra M.; Hayward, William G.; O'Callaghan, Claire; Andrews, Sally

    2012-01-01

    We used repetition blindness to investigate the nature of the representations underlying identification of manipulable objects. Observers named objects presented in rapid serial visual presentation streams containing either manipulable or nonmanipulable objects. In half the streams, 1 object was repeated. Overall accuracy was lower when streams…

  2. Grounded Object and Grasp Representations in a Cognitive Architecture

    DEFF Research Database (Denmark)

    Kraft, Dirk

    . We also explain how the feature-action relationship can be improved through learning from a set of experiences. Once physical control is achieved, we can move the object in such a way that we can gather visual information from different viewpoints. We describe how this information can be integrated......Robotic systems are today still mostly unable to perform complex tasks in unknown environments. While there have been many approaches to cope with unknown environments, for example in mobile robot navigation, the work done when it comes to more complex tasks, for example object handling are, less...... 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...

  3. An application of object-oriented knowledge representation to engineering expert systems

    Science.gov (United States)

    Logie, D. S.; Kamil, H.; Umaretiya, J. R.

    1990-01-01

    The paper describes an object-oriented knowledge representation and its application to engineering expert systems. The object-oriented approach promotes efficient handling of the problem data by allowing knowledge to be encapsulated in objects and organized by defining relationships between the objects. An Object Representation Language (ORL) was implemented as a tool for building and manipulating the object base. Rule-based knowledge representation is then used to simulate engineering design reasoning. Using a common object base, very large expert systems can be developed, comprised of small, individually processed, rule sets. The integration of these two schemes makes it easier to develop practical engineering expert systems. The general approach to applying this technology to the domain of the finite element analysis, design, and optimization of aerospace structures is discussed.

  4. Generalization and specialization of object dynamics

    NARCIS (Netherlands)

    Gamito Dignum, V.; Riet, van de R.P.; Wieringa, R.

    1989-01-01

    This report presents a quite detailed analysis of the modeling approaches of different object-oriented database systems, namely ABSURD, OBLOG, MOKUM, TAXIS and GAL/LEO, with emphasis on the spuialization of object dynamics, in a taxonomic structure. It is done unifonnly l7y applying each system to t

  5. Goal-directed attention alters the tuning of object-based representations in extrastriate cortex

    Directory of Open Access Journals (Sweden)

    Anthony J.-W. Chen

    2012-06-01

    Full Text Available Humans survive in environments that contain a vast quantity and variety of visual information. All items of perceived visual information must be represented within a limited number of brain networks. The human brain requires mechanisms for selecting only a relevant fraction of perceived information for more in-depth processing, where neural representations of that information may be actively maintained and utilized for goal-directed behavior. Object-based attention is crucial for goal-directed behavior and yet remains poorly understood. Thus, in the study we investigate how neural representations of visual object information are guided by selective attention. The magnitude of activation in human extrastriate cortex has been shown to be modulated by attention; however object-based attention is not likely to be fully explained by a localized gain mechanism. Thus, we measured information coded in spatially distributed patterns of brain activity with fMRI while human participants performed a task requiring selective processing of a relevant visual object category that differed across conditions. Using pattern classification and spatial correlation techniques, we found that the direction of selective attention is implemented as a shift in the tuning of object-based information representations within extrastriate cortex. In contrast, we found that representations within lateral prefrontal cortex coded for the attention condition rather than the concrete representations of object category. In sum, our findings are consistent with a model of object-based selective attention in which representations coded within extrastriate cortex are tuned to favor the representation of goal-relevant information, guided by more abstract representations within lateral prefrontal cortex.

  6. Vaguely defined objects representations, fuzzy sets and nonclassical cardinality theory

    CERN Document Server

    Wygralak, Maciej

    1996-01-01

    In recent years, an impetuous development of new, unconventional theories, methods, techniques and technologies in computer and information sciences, systems analysis, decision-making and control, expert systems, data modelling, engineering, etc. , resulted in a considerable increase of interest in adequate mathematical description and analysis of objects, phenomena, and processes which are vague or imprecise by their very nature. Classical two-valued logic and the related notion of a set, together with its mathematical consequences, are then often inadequate or insufficient formal tools, and can even become useless for applications because of their (too) categorical character: 'true - false', 'belongs - does not belong', 'is - is not', 'black - white', '0 - 1', etc. This is why one replaces classical logic by various types of many-valued logics and, on the other hand, more general notions are introduced instead of or beside that of a set. Let us mention, for instance, fuzzy sets and derivative concepts, flou...

  7. The neural basis of individual face and object representation

    Directory of Open Access Journals (Sweden)

    Rebecca eWatson

    2016-03-01

    Full Text Available We routinely need to process the identity of many faces around us, and how the brain achieves this is still the subject of much research in cognitive neuroscience. To date, insights on face identity processing have come from both healthy and clinical populations. However, in order to directly compare results across and within participant groups, and across different studies, it is crucial that a standard task is utilised which includes different exemplars (for example, non-face stimuli along with faces, is memory-neutral, and taps into identity recognition across orientation and across viewpoint change. The goal of this study was to test a previously behaviourally tested, optimised face and object identity matching design in a healthy control sample whilst being scanned using fMRI. Specifically, we investigated categorical, orientation, and category-specific orientation effects while participants were focused on identity processing of simultaneously presented exemplar stimuli. Alongside observing category and orientation specific effects in a distributed set of brain regions, we also saw an interaction between stimulus category and orientation in the bilateral fusiform gyrus and bilateral middle occipital gyrus. Generally these clusters showed the pattern of a heightened response to inverted, as opposed to upright faces; and to upright, as opposed to inverted shoes. These results are discussed in relation to previous studies and to potential future research within prosopagnosic individuals.

  8. Strength of object representation: its key role in object-based attention for determining the competition result between Gestalt and top-down objects.

    Science.gov (United States)

    Zhao, Jingjing; Wang, Yonghui; Liu, Donglai; Zhao, Liang; Liu, Peng

    2015-10-01

    It was found in previous studies that two types of objects (rectangles formed according to the Gestalt principle and Chinese words formed in a top-down fashion) can both induce an object-based effect. The aim of the present study was to investigate how the strength of an object representation affects the result of the competition between these two types of objects based on research carried out by Liu, Wang and Zhou [(2011) Acta Psychologica, 138(3), 397-404]. In Experiment 1, the rectangles were filled with two different colors to increase the strength of Gestalt object representation, and we found that the object effect changed significantly for the different stimulus types. Experiment 2 used Chinese words with various familiarities to manipulate the strength of the top-down object representation. As a result, the object-based effect induced by rectangles was observed only when the Chinese word familiarity was low. These results suggest that the strength of object representation determines the result of competition between different types of objects.

  9. Adaptive object recognition model using incremental feature representation and hierarchical classification.

    Science.gov (United States)

    Jeong, Sungmoon; Lee, Minho

    2012-01-01

    This paper presents an adaptive object recognition model based on incremental feature representation and a hierarchical feature classifier that offers plasticity to accommodate additional input data and reduces the problem of forgetting previously learned information. The incremental feature representation method applies adaptive prototype generation with a cortex-like mechanism to conventional feature representation to enable an incremental reflection of various object characteristics, such as feature dimensions in the learning process. A feature classifier based on using a hierarchical generative model recognizes various objects with variant feature dimensions during the learning process. Experimental results show that the adaptive object recognition model successfully recognizes single and multiple-object classes with enhanced stability and flexibility.

  10. Dynamical symmetry breaking with hypercolour and high colour representations

    Energy Technology Data Exchange (ETDEWEB)

    Zoupanos, G.

    1985-03-01

    A model is presented in which the electroweak gauge group is spontaneously broken according to a dynamical scenario based on the existence of high colour representations. An unattractive feature of this scenario was the necessity to introduce elementary Higgs fields in order to obtain the spontaneous symmetry breaking of part of the theory. In the present model, this breaking can also be understood dynamically with the introduction of hypercolour interactions.

  11. Common Representation of Information Flows for Dynamic Coalitions

    CERN Document Server

    Mozolevsky, Igor; 10.4204/EPTCS.16.2

    2010-01-01

    We propose a formal foundation for reasoning about access control policies within a Dynamic Coalition, defining an abstraction over existing access control models and providing mechanisms for translation of those models into information-flow domain. The abstracted information-flow domain model, called a Common Representation, can then be used for defining a way to control the evolution of Dynamic Coalitions with respect to information flow.

  12. Evidence for Similar Early but Not Late Representation of Possible and Impossible Objects

    Directory of Open Access Journals (Sweden)

    Erez eFreud

    2015-02-01

    Full Text Available The perceptual processes that mediate the ability to efficiently represent object 3D structure are still not fully understood. The current study was aimed to shed light on these processes by utilizing spatially possible and impossible objects that could not be created in real 3D space. Despite being perceived as exceptionally unusual, impossible objects still possess fundamental Gestalt attributes and valid local depth cues that may support their initial successful representation. Based on this notion and on recent findings from our lab, we hypothesized that the initial representation of impossible objects would involve common mechanisms to those mediating typical object perception while the perceived differences between possible and impossible objects would emerge later along the processing hierarchy. In Experiment 1, participants preformed same/different classifications of two markers superimposed on a display with two objects (possible or impossible. Faster reaction times were observed for displays in which the markers were superimposed on the same object (object-based benefit. Importantly, this benefit was similar for possible and impossible objects, suggesting that the representations of the two object categories rely on similar perceptual organized processes. Yet, responses for impossible objects were slower compared to possible objects. Experiment 2 was designed to examine the origin of this effect. Participants classified the location of two markers while exposure duration was manipulated. A similar pattern of performance was found for possible and impossible objects for the short exposure duration, with differences in accuracy between these two types of objects emerging only for longer exposure durations. Overall, these findings provide evidence that the representation of object structure relies on a multi-level process and that object impossibility selectively impairs the rendering of fine-detailed description of object structure.

  13. Size-sensitive perceptual representations underlie visual and haptic object recognition.

    Directory of Open Access Journals (Sweden)

    Matt Craddock

    Full Text Available A variety of similarities between visual and haptic object recognition suggests that the two modalities may share common representations. However, it is unclear whether such common representations preserve low-level perceptual features or whether transfer between vision and haptics is mediated by high-level, abstract representations. Two experiments used a sequential shape-matching task to examine the effects of size changes on unimodal and crossmodal visual and haptic object recognition. Participants felt or saw 3D plastic models of familiar objects. The two objects presented on a trial were either the same size or different sizes and were the same shape or different but similar shapes. Participants were told to ignore size changes and to match on shape alone. In Experiment 1, size changes on same-shape trials impaired performance similarly for both visual-to-visual and haptic-to-haptic shape matching. In Experiment 2, size changes impaired performance on both visual-to-haptic and haptic-to-visual shape matching and there was no interaction between the cost of size changes and direction of transfer. Together the unimodal and crossmodal matching results suggest that the same, size-specific perceptual representations underlie both visual and haptic object recognition, and indicate that crossmodal memory for objects must be at least partly based on common perceptual representations.

  14. Control-volume representation of molecular dynamics.

    Science.gov (United States)

    Smith, E R; Heyes, D M; Dini, D; Zaki, T A

    2012-05-01

    A molecular dynamics (MD) parallel to the control volume (CV) formulation of fluid mechanics is developed by integrating the formulas of Irving and Kirkwood [J. Chem. Phys. 18, 817 (1950)] over a finite cubic volume of molecular dimensions. The Lagrangian molecular system is expressed in terms of an Eulerian CV, which yields an equivalent to Reynolds' transport theorem for the discrete system. This approach casts the dynamics of the molecular system into a form that can be readily compared to the continuum equations. The MD equations of motion are reinterpreted in terms of a Lagrangian-to-control-volume (LCV) conversion function ϑ(i) for each molecule i. The LCV function and its spatial derivatives are used to express fluxes and relevant forces across the control surfaces. The relationship between the local pressures computed using the volume average [Lutsko, J. Appl. Phys. 64, 1152 (1988)] techniques and the method of planes [Todd et al., Phys. Rev. E 52, 1627 (1995)] emerges naturally from the treatment. Numerical experiments using the MD CV method are reported for equilibrium and nonequilibrium (start-up Couette flow) model liquids, which demonstrate the advantages of the formulation. The CV formulation of the MD is shown to be exactly conservative and is, therefore, ideally suited to obtain macroscopic properties from a discrete system.

  15. Representations and Techniques for 3D Object Recognition and Scene Interpretation

    CERN Document Server

    Hoiem, Derek

    2011-01-01

    One of the grand challenges of artificial intelligence is to enable computers to interpret 3D scenes and objects from imagery. This book organizes and introduces major concepts in 3D scene and object representation and inference from still images, with a focus on recent efforts to fuse models of geometry and perspective with statistical machine learning. The book is organized into three sections: (1) Interpretation of Physical Space; (2) Recognition of 3D Objects; and (3) Integrated 3D Scene Interpretation. The first discusses representations of spatial layout and techniques to interpret physi

  16. Dynamic Representation Of Adverbs in Chinese version

    Institute of Scientific and Technical Information of China (English)

    林凡荣

    2014-01-01

    Owing to the Characteristic of English Language,perpositions and adverbs play an important role in English Language.They can transmit dynamic meaning when they are translated from English into Chinese.But why and how?I’ll elaborate upon this question in this paper.As we all know,Chinese and English are two different languages. So,there is no doubt that many differences exist when one language is translated into the other language.Lat’s look at this sentence:“Partyofficials worked long hours,on meager food,in cold caves,by dim lamps.”When the sentense is translated into Chinese,its meaning is:党的干部长时间地工作,吃粗陋的食物,住冰冷的洞穴,点昏暗的灯.So we have no difficulty in finding that the three prepositions“on,in,by”in English sentence are translated as “吃,住,点”,but why can the prepositions in English be translated as verbs inChinese.This is because Chinese is a dynamic Language while English is a static one.As we all know,verbs used in Chinese are much more than thse used in English.In English,one sentence often has one preposition and adverbs can often be translated as verbs.When they are translated from English into Chinese.But how do prepositions and adverbs reflect their dtnamic Characteristics?Let’s state it in the following aspects.

  17. Mirror-Image Confusions: Implications for Representation and Processing of Object Orientation

    Science.gov (United States)

    Gregory, Emma; McCloskey, Michael

    2010-01-01

    Perceiving the orientation of objects is important for interacting with the world, yet little is known about the mental representation or processing of object orientation information. The tendency of humans and other species to confuse mirror images provides a potential clue. However, the appropriate characterization of this phenomenon is not…

  18. Object Oriented Modelling and Dynamical Simulation

    DEFF Research Database (Denmark)

    Wagner, Falko Jens; Poulsen, Mikael Zebbelin

    1998-01-01

    This report with appendix describes the work done in master project at DTU.The goal of the project was to develop a concept for simulation of dynamical systems based on object oriented methods.The result was a library of C++-classes, for use when both building componentbased models and when...

  19. Object Oriented Modelling and Dynamical Simulation

    DEFF Research Database (Denmark)

    Wagner, Falko Jens; Poulsen, Mikael Zebbelin

    1998-01-01

    This report with appendix describes the work done in master project at DTU.The goal of the project was to develop a concept for simulation of dynamical systems based on object oriented methods.The result was a library of C++-classes, for use when both building componentbased models and when...... onduction simulation experiments....

  20. Dynamic multi-objective optimisation using PSO

    CSIR Research Space (South Africa)

    Greeff, M

    2010-01-01

    Full Text Available Functions. In Proc. of 2nd Italian Workshop on Evolutionary Computation and 3rd Italian Workshop on Artificial Life, 2006. 13. I. Hatzakis and D. Wallace. Dynamic Multi-Objective Optimization with Evolu- tionary Algorithms: A Forward Looking Approach...

  1. Object-oriented echo perception and cortical representation in echolocating bats.

    Science.gov (United States)

    Firzlaff, Uwe; Schuchmann, Maike; Grunwald, Jan E; Schuller, Gerd; Wiegrebe, Lutz

    2007-05-01

    Echolocating bats can identify three-dimensional objects exclusively through the analysis of acoustic echoes of their ultrasonic emissions. However, objects of the same structure can differ in size, and the auditory system must achieve a size-invariant, normalized object representation for reliable object recognition. This study describes both the behavioral classification and the cortical neural representation of echoes of complex virtual objects that vary in object size. In a phantom-target playback experiment, it is shown that the bat Phyllostomus discolor spontaneously classifies most scaled versions of objects according to trained standards. This psychophysical performance is reflected in the electrophysiological responses of a population of cortical units that showed an object-size invariant response (14/109 units, 13%). These units respond preferentially to echoes from objects in which echo duration (encoding object depth) and echo amplitude (encoding object surface area) co-varies in a meaningful manner. These results indicate that at the level of the bat's auditory cortex, an object-oriented rather than a stimulus-parameter-oriented representation of echoes is achieved.

  2. Object representation for multi-beam sonar image using local higher-order statistics

    Science.gov (United States)

    Li, Haisen; Gao, Jue; Du, Weidong; Zhou, Tian; Xu, Chao; Chen, Baowei

    2017-01-01

    Multi-beam sonar imaging has been widely used in various underwater tasks such as object recognition and object tracking. Problems remain, however, when the sonar images are characterized by low signal-to-noise ratio, low resolution, and amplitude alterations due to viewpoint changes. This paper investigates the capacity of local higher-order statistics (HOS) to represent objects in multi-beam sonar images. The Weibull distribution has been used for modeling the background of the image. Local HOS involving skewness is estimated using a sliding computational window, thus generating the local skewness image of which a square structure is associated with a potential object. The ability of object representation with different signal-to-noise ratio (SNR) between object and background is analyzed, and the choice of the computational window size is discussed. In the case of the object with high SNR, a novel algorithm based on background estimation is proposed to reduce side lobe and retain object regions. The performance of object representation has been evaluated using real data that provided encouraging results in the case of the object with low amplitude, high side lobes, or large fluctuant amplitude. In conclusion, local HOS provides more reliable and stable information relating to the potential object and improves the object representation in multi-beam sonar image.

  3. Deep neural networks rival the representation of primate IT cortex for core visual object recognition.

    Directory of Open Access Journals (Sweden)

    Charles F Cadieu

    2014-12-01

    Full Text Available The primate visual system achieves remarkable visual object recognition performance even in brief presentations, and under changes to object exemplar, geometric transformations, and background variation (a.k.a. core visual object recognition. This remarkable performance is mediated by the representation formed in inferior temporal (IT cortex. In parallel, recent advances in machine learning have led to ever higher performing models of object recognition using artificial deep neural networks (DNNs. It remains unclear, however, whether the representational performance of DNNs rivals that of the brain. To accurately produce such a comparison, a major difficulty has been a unifying metric that accounts for experimental limitations, such as the amount of noise, the number of neural recording sites, and the number of trials, and computational limitations, such as the complexity of the decoding classifier and the number of classifier training examples. In this work, we perform a direct comparison that corrects for these experimental limitations and computational considerations. As part of our methodology, we propose an extension of "kernel analysis" that measures the generalization accuracy as a function of representational complexity. Our evaluations show that, unlike previous bio-inspired models, the latest DNNs rival the representational performance of IT cortex on this visual object recognition task. Furthermore, we show that models that perform well on measures of representational performance also perform well on measures of representational similarity to IT, and on measures of predicting individual IT multi-unit responses. Whether these DNNs rely on computational mechanisms similar to the primate visual system is yet to be determined, but, unlike all previous bio-inspired models, that possibility cannot be ruled out merely on representational performance grounds.

  4. A Unified Representation Scheme for Solid Geometric Objects Using B-splines (extended Abstract)

    Science.gov (United States)

    Bahler, D.

    1985-01-01

    A geometric representation scheme called the B-spline cylinder, which consists of interpolation between pairs of uniform periodic cubic B-spline curves is discussed. This approach carries a number of interesting implications. For one, a single relatively simple database schema can be used to represent a reasonably large class of objects, since the spline representation is flexible enough to allow a large domain of representable objects at very little cost in data complexity. The model is thus very storage-efficient. A second feature of such a system is that it reduces to one the number of routines which the system must support to perform a given operation on objects. Third, the scheme enables easy conversion to and from other representations. The formal definition of the cylinder entity is given. In the geometric properties of the entity are explored and several operations on such objects are defined. Some general purpose criteria for evaluating any geometric representation scheme are introduced and the B-spline cylinder scheme according to these criteria is evaluated.

  5. Implicit kernel sparse shape representation: a sparse-neighbors-based objection segmentation framework.

    Science.gov (United States)

    Yao, Jincao; Yu, Huimin; Hu, Roland

    2017-01-01

    This paper introduces a new implicit-kernel-sparse-shape-representation-based object segmentation framework. Given an input object whose shape is similar to some of the elements in the training set, the proposed model can automatically find a cluster of implicit kernel sparse neighbors to approximately represent the input shape and guide the segmentation. A distance-constrained probabilistic definition together with a dualization energy term is developed to connect high-level shape representation and low-level image information. We theoretically prove that our model not only derives from two projected convex sets but is also equivalent to a sparse-reconstruction-error-based representation in the Hilbert space. Finally, a "wake-sleep"-based segmentation framework is applied to drive the evolutionary curve to recover the original shape of the object. We test our model on two public datasets. Numerical experiments on both synthetic images and real applications show the superior capabilities of the proposed framework.

  6. Representations and antinomies: rural and city social objects in a Brazilian peasant community.

    Science.gov (United States)

    Bonomo, Mariana; de Souza, Lídio; Trindade, Zeidi Araujo; Menandro, Maria Cristina Smith

    2013-01-01

    The present work is part of a series of studies that primarily focus on social representations of rural and city objects in the process of constructing a social identity of the countryside. Using social representation theory, this study aimed to investigate the representational field linked to the rural and city objects for the members of a peasant community. A total of 200 members of a Brazilian rural community from four generational groups, of both sexes and aged between 7 and 81 years, participated in this study. We conducted individual interviews with semi-structured scripts. The data corpora, processed using EVOC software, consisted of free associations of the rural and city inductor terms. In constitutive terms, the results allow for the identification of antinomies between the objects discussed; in functional terms, they indicate that the process of constructing social identity is based on the symbolic field, which acts as a reference system for the preparation of the rural identity shared by the participants.

  7. Edge detection based on object tree image representation and wavelet transform

    Institute of Scientific and Technical Information of China (English)

    屈彦呈; 王常虹; 庄显义

    2003-01-01

    In applications such as image retrieval and recognition, precise edge detection for interested regions plays a decisive role. Existing methods generally take little care about local characteristics, or become time-consuming if every detail is considered. In the paper, a new method is put forward based on the combination of effective image representation and multiscale wavelet analysis. A new object tree image representation is introduced. Then a series of object trees are constructed based on wavelet transform modulus maxima at different scales in descending order. Computation is only needed for interested regions. Implementation steps are also given with an illustrative example.

  8. A Neural Dynamic Model Generates Descriptions of Object-Oriented Actions.

    Science.gov (United States)

    Richter, Mathis; Lins, Jonas; Schöner, Gregor

    2017-01-01

    Describing actions entails that relations between objects are discovered. A pervasively neural account of this process requires that fundamental problems are solved: the neural pointer problem, the binding problem, and the problem of generating discrete processing steps from time-continuous neural processes. We present a prototypical solution to these problems in a neural dynamic model that comprises dynamic neural fields holding representations close to sensorimotor surfaces as well as dynamic neural nodes holding discrete, language-like representations. Making the connection between these two types of representations enables the model to describe actions as well as to perceptually ground movement phrases-all based on real visual input. We demonstrate how the dynamic neural processes autonomously generate the processing steps required to describe or ground object-oriented actions. By solving the fundamental problems of neural pointing, binding, and emergent discrete processing, the model may be a first but critical step toward a systematic neural processing account of higher cognition.

  9. Disentangling Representations of Object Shape and Object Category in Human Visual Cortex: The Animate-Inanimate Distinction.

    Science.gov (United States)

    Proklova, Daria; Kaiser, Daniel; Peelen, Marius V

    2016-05-01

    Objects belonging to different categories evoke reliably different fMRI activity patterns in human occipitotemporal cortex, with the most prominent distinction being that between animate and inanimate objects. An unresolved question is whether these categorical distinctions reflect category-associated visual properties of objects or whether they genuinely reflect object category. Here, we addressed this question by measuring fMRI responses to animate and inanimate objects that were closely matched for shape and low-level visual features. Univariate contrasts revealed animate- and inanimate-preferring regions in ventral and lateral temporal cortex even for individually matched object pairs (e.g., snake-rope). Using representational similarity analysis, we mapped out brain regions in which the pairwise dissimilarity of multivoxel activity patterns (neural dissimilarity) was predicted by the objects' pairwise visual dissimilarity and/or their categorical dissimilarity. Visual dissimilarity was measured as the time it took participants to find a unique target among identical distractors in three visual search experiments, where we separately quantified overall dissimilarity, outline dissimilarity, and texture dissimilarity. All three visual dissimilarity structures predicted neural dissimilarity in regions of visual cortex. Interestingly, these analyses revealed several clusters in which categorical dissimilarity predicted neural dissimilarity after regressing out visual dissimilarity. Together, these results suggest that the animate-inanimate organization of human visual cortex is not fully explained by differences in the characteristic shape or texture properties of animals and inanimate objects. Instead, representations of visual object properties and object category may coexist in more anterior parts of the visual system.

  10. The temporal dynamics of visual object priming.

    Science.gov (United States)

    Ko, Philip C; Duda, Bryant; Hussey, Erin P; Mason, Emily J; Ally, Brandon A

    2014-11-01

    Priming reflects an important means of learning that is mediated by implicit memory. Importantly, priming occurs for previously viewed objects (item-specific priming) and their category relatives (category-wide priming). Two distinct neural mechanisms are known to mediate priming, including the sharpening of a neural object representation and the retrieval of stimulus-response mappings. Here, we investigated whether the relationship between these neural mechanisms could help explain why item-specific priming generates faster responses than category-wide priming. Participants studied pictures of everyday objects, and then performed a difficult picture identification task while we recorded event-related potentials (ERP). The identification task gradually revealed random line segments of previously viewed items (Studied), category exemplars of previously viewed items (Exemplar), and items that were not previously viewed (Unstudied). Studied items were identified sooner than Unstudied items, showing evidence of item-specific priming, and importantly Exemplar items were also identified sooner than Unstudied items, showing evidence of category-wide priming. Early activity showed sustained neural suppression of parietal activity for both types of priming. However, these neural suppression effects may have stemmed from distinct processes because while category-wide neural suppression was correlated with priming behavior, item-specific neural suppression was not. Late activity, examined with response-locked ERPs, showed additional processes related to item-specific priming including neural suppression in occipital areas and parietal activity that was correlated with behavior. Together, we conclude that item-specific and category-wide priming are mediated by separate, parallel neural mechanisms in the context of the current paradigm. Temporal differences in behavior are determined by the timecourses of these distinct processes.

  11. The Game Object Model and Expansive Learning: Creation, Instantiation, Expansion, and Re-representation

    Science.gov (United States)

    Amory, Alan; Molomo, Bolepo; Blignaut, Seugnet

    2011-01-01

    In this paper, the collaborative development, instantiation, expansion and re-representation as research instrument of the Game Object Model (GOM) are explored from a Cultural Historical Activity Theory perspective. The aim of the paper is to develop insights into the design, integration, evaluation and use of video games in learning and teaching.…

  12. The Nature of Experience Determines Object Representations in the Visual System

    Science.gov (United States)

    Wong, Yetta K.; Folstein, Jonathan R.; Gauthier, Isabel

    2012-01-01

    Visual perceptual learning (PL) and perceptual expertise (PE) traditionally lead to different training effects and recruit different brain areas, but reasons for these differences are largely unknown. Here, we tested how the learning history influences visual object representations. Two groups were trained with tasks typically used in PL or PE…

  13. Reward Selectively Modulates the Lingering Neural Representation of Recently Attended Objects in Natural Scenes.

    Science.gov (United States)

    Hickey, Clayton; Peelen, Marius V

    2017-08-02

    Theories of reinforcement learning and approach behavior suggest that reward can increase the perceptual salience of environmental stimuli, ensuring that potential predictors of outcome are noticed in the future. However, outcome commonly follows visual processing of the environment, occurring even when potential reward cues have long disappeared. How can reward feedback retroactively cause now-absent stimuli to become attention-drawing in the future? One possibility is that reward and attention interact to prime lingering visual representations of attended stimuli that sustain through the interval separating stimulus and outcome. Here, we test this idea using multivariate pattern analysis of fMRI data collected from male and female humans. While in the scanner, participants searched for examples of target categories in briefly presented pictures of cityscapes and landscapes. Correct task performance was followed by reward feedback that could randomly have either high or low magnitude. Analysis showed that high-magnitude reward feedback boosted the lingering representation of target categories while reducing the representation of nontarget categories. The magnitude of this effect in each participant predicted the behavioral impact of reward on search performance in subsequent trials. Other analyses show that sensitivity to reward-as expressed in a personality questionnaire and in reactivity to reward feedback in the dopaminergic midbrain-predicted reward-elicited variance in lingering target and nontarget representations. Credit for rewarding outcome thus appears to be assigned to the target representation, causing the visual system to become sensitized for similar objects in the future.SIGNIFICANCE STATEMENT How do reward-predictive visual stimuli become salient and attention-drawing? In the real world, reward cues precede outcome and reward is commonly received long after potential predictors have disappeared. How can the representation of environmental stimuli

  14. Manipulation after object rotation reveals independent sensorimotor memory representations of digit positions and forces.

    Science.gov (United States)

    Zhang, Wei; Gordon, Andrew M; Fu, Qiushi; Santello, Marco

    2010-06-01

    Planning of object manipulations is dependent on the ability to generate, store, and retrieve sensorimotor memories of previous actions associated with grasped objects. However, the sensorimotor memory representations linking object properties to the planning of grasp are not well understood. Here we use an object rotation task to gain insight into the mechanisms underlying the nature of these sensorimotor memories. We asked subjects to grasp a grip device with an asymmetrical center of mass (CM) anywhere on its vertical surfaces and lift it while minimizing object roll. After subjects learned to minimize object roll by generating a compensatory moment, they were asked to rotate the object 180 degrees about a vertical axis and lift it again. The rotation resulted in changing the direction of external moment opposite to that experienced during the prerotation block. Anticipatory grasp control was quantified by measuring the compensatory moment generated at object lift onset by thumb and index finger forces through their respective application points. On the first postrotation trial, subjects failed to generate a compensatory moment to counter the external moment caused by the new CM location, thus resulting in a large object roll. Nevertheless, after several object rotations subjects reduced object roll on the initial postrotation trials by anticipating the new CM location through the modulation of digit placement but not tangential forces. The differential improvement in modulating these two variables supports the notion of independent memory representations of kinematics and kinetics and is discussed in relation to neural mechanisms underlying visuomotor transformations.

  15. Gravity influences the visual representation of object tilt in parietal cortex.

    Science.gov (United States)

    Rosenberg, Ari; Angelaki, Dora E

    2014-10-22

    Sensory systems encode the environment in egocentric (e.g., eye, head, or body) reference frames, creating inherently unstable representations that shift and rotate as we move. However, it is widely speculated that the brain transforms these signals into an allocentric, gravity-centered representation of the world that is stable and independent of the observer's spatial pose. Where and how this representation may be achieved is currently unknown. Here we demonstrate that a subpopulation of neurons in the macaque caudal intraparietal area (CIP) visually encodes object tilt in nonegocentric coordinates defined relative to the gravitational vector. Neuronal responses to the tilt of a visually presented planar surface were measured with the monkey in different spatial orientations (upright and rolled left/right ear down) and then compared. This revealed a continuum of representations in which planar tilt was encoded in a gravity-centered reference frame in approximately one-tenth of the comparisons, intermediate reference frames ranging between gravity-centered and egocentric in approximately two-tenths of the comparisons, and in an egocentric reference frame in less than half of the comparisons. Altogether, almost half of the comparisons revealed a shift in the preferred tilt and/or a gain change consistent with encoding object orientation in nonegocentric coordinates. Through neural network modeling, we further show that a purely gravity-centered representation of object tilt can be achieved directly from the population activity of CIP-like units. These results suggest that area CIP may play a key role in creating a stable, allocentric representation of the environment defined relative to an "earth-vertical" direction. Copyright © 2014 the authors 0270-6474/14/3414170-11$15.00/0.

  16. Multivoxel Object Representations in Adult Human Visual Cortex Are Flexible: An Associative Learning Study.

    Science.gov (United States)

    Senoussi, Mehdi; Berry, Isabelle; VanRullen, Rufin; Reddy, Leila

    2016-06-01

    Learning associations between co-occurring events enables us to extract structure from our environment. Medial-temporal lobe structures are critical for associative learning. However, the role of the ventral visual pathway (VVP) in associative learning is not clear. Do multivoxel object representations in the VVP reflect newly formed associations? We show that VVP multivoxel representations become more similar to each other after human participants learn arbitrary new associations between pairs of unrelated objects (faces, houses, cars, chairs). Participants were scanned before and after 15 days of associative learning. To evaluate how object representations changed, a classifier was trained on discriminating two nonassociated categories (e.g., faces/houses) and tested on discriminating their paired associates (e.g., cars/chairs). Because the associations were arbitrary and counterbalanced across participants, there was initially no particular reason for this cross-classification decision to tend toward either alternative. Nonetheless, after learning, cross-classification performance increased in the VVP (but not hippocampus), on average by 3.3%, with some voxels showing increases of up to 10%. For example, a chair multivoxel representation that initially resembled neither face nor house representations was, after learning, classified as more similar to that of faces for participants who associated chairs with faces and to that of houses for participants who associated chairs with houses. Additionally, learning produced long-lasting perceptual consequences. In a behavioral priming experiment performed several months later, the change in cross-classification performance was correlated with the degree of priming. Thus, VVP multivoxel representations are not static but become more similar to each other after associative learning.

  17. Geometrical dynamics of Born-Infeld objects

    Energy Technology Data Exchange (ETDEWEB)

    Cordero, Ruben [Departamento de Fisica, Escuela Superior de Fisica y Matematicas del I.P.N., Unidad Adolfo Lopez Mateos, Edificio 9, 07738 Mexico, D.F. (Mexico); Molgado, Alberto [Facultad de Ciencias, Universidad de Colima, Bernal DIaz del Castillo 340, Col. Villas San Sebastian, Colima (Mexico); Rojas, Efrain [Facultad de Fisica e Inteligencia Artificial, Universidad Veracruzana, 91000 Xalapa, Veracruz (Mexico)

    2007-03-21

    We present a geometrically inspired study of the dynamics of Dp-branes. We focus on the usual non-polynomial Dirac-Born-Infeld action for the worldvolume swept out by the brane in its evolution in general background spacetimes. We emphasize the form of the resulting equations of motion which are quite simple and resemble Newton's second law, complemented with a conservation law for a worldvolume bicurrent. We take a closer look at the classical Hamiltonian analysis which is supported by the ADM framework of general relativity. The constraints and their algebra are identified as well as the geometrical role they play in phase space. In order to illustrate our results, we review the dynamics of a D1-brane immersed in a AdS{sub 3} x S{sup 3} background spacetime. We exhibit the mechanical properties of Born-Infeld objects paving the way to a consistent quantum formulation.

  18. System for conversion between the boundary representation model and a constructive solid geometry model of an object

    Science.gov (United States)

    Christensen, Noel C.; Emery, James D.; Smith, Maurice L.

    1988-04-05

    A system converts from the boundary representation of an object to the constructive solid geometry representation thereof. The system converts the boundary representation of the object into elemental atomic geometrical units or I-bodies which are in the shape of stock primitives or regularized intersections of stock primitives. These elemental atomic geometrical units are then represented in symbolic form. The symbolic representations of the elemental atomic geometrical units are then assembled heuristically to form a constructive solid geometry representation of the object usable for manufacturing thereof. Artificial intelligence is used to determine the best constructive solid geometry representation from the boundary representation of the object. Heuristic criteria are adapted to the manufacturing environment for which the device is to be utilized. The surface finish, tolerance, and other information associated with each surface of the boundary representation of the object are mapped onto the constructive solid geometry representation of the object to produce an enhanced solid geometry representation, particularly useful for computer-aided manufacture of the object.

  19. Indirect Object Representation and Access by Means of Concepts : technical report

    CERN Document Server

    Savinov, Alexandr

    2006-01-01

    The paper describes a mechanism for indirect object representation and access (ORA) in programming languages. The mechanism is based on using a new programming construct which is referred to as concept. Concept consists of one object class and one reference class both having their fields and methods. The object class is the conventional class as defined in OOP with instances passed by reference. Instances of the reference class are passed by value and are intended to represent objects. The reference classes are used to describe how objects have to be represented and accessed by providing custom format for their identifiers and custom access procedures. Such an approach to programming where concepts are used instead of classes is referred to as concept-oriented programming. It generalizes OOP and its main advantage is that it allows the programmer to describe not only the functionality of target objects but also intermediate functions which are executed behind the scenes as an object is being accessed.

  20. MODELING OF DYNAMIC SYSTEMS WITH MODULATION BY MEANS OF KRONECKER VECTOR-MATRIX REPRESENTATION

    Directory of Open Access Journals (Sweden)

    A. S. Vasilyev

    2015-09-01

    Full Text Available The paper deals with modeling of dynamic systems with modulation by the possibilities of state-space method. This method, being the basis of modern control theory, is based on the possibilities of vector-matrix formalism of linear algebra and helps to solve various problems of technical control of continuous and discrete nature invariant with respect to the dimension of their “input-output” objects. Unfortunately, it turned its back on the wide group of control systems, which hardware environment modulates signals. The marked system deficiency is partially offset by this paper, which proposes Kronecker vector-matrix representations for purposes of system representation of processes with signal modulation. The main result is vector-matrix representation of processes with modulation with no formal difference from continuous systems. It has been found that abilities of these representations could be effectively used in research of systems with modulation. Obtained model representations of processes with modulation are best adapted to the state-space method. These approaches for counting eigenvalues of Kronecker matrix summaries, that are matrix basis of model representations of processes described by Kronecker vector products, give the possibility to use modal direction in research of dynamics for systems with modulation. It is shown that the use of controllability for eigenvalues of general matrixes applied to Kronecker structures enabled to divide successfully eigenvalue spectrum into directed and not directed components. Obtained findings including design problems for models of dynamic processes with modulation based on the features of Kronecker vector and matrix structures, invariant with respect to the dimension of input-output relations, are applicable in the development of alternate current servo drives.

  1. Discrete object representation, attention switching, and task difficulty in the parietal lobe.

    Science.gov (United States)

    Cusack, Rhodri; Mitchell, Daniel J; Duncan, John

    2010-01-01

    An important component of perception, attention, and memory is the structuring of information into subsets ("objects"), which allows some parts to be considered together but kept separate from others. Portions of the posterior parietal lobe respond proportionally to the number of objects in the scope of attention and short-term memory, up to a capacity limit of around four, suggesting they have a role in this important process. This study investigates the relationship of discrete object representation to other parietal functions. Two experiments and two supplementary analyses were conducted to evaluate responsivity in parietal regions to the number of objects, the number of spatial locations, attention switching, and general task difficulty. Using transparent motion, it was found that a posterior and inferior parietal response to multiple objects persists even in the absence of a change in visual extent or the number of spatial locations. In a monitoring task, it was found that attention switching (or task difficulty) and object representation have distinct neural signatures, with the former showing greater recruitment of an anterior and lateral intraparietal sulcus (IPS) region, but the latter in a posterior and lateral region. A dissociation was also seen between selectivity for object load across tasks in the inferior IPS and feature or object-related memory load in the superior IPS.

  2. Dynamic stability of sequential stimulus representations in adapting neuronal networks

    Directory of Open Access Journals (Sweden)

    Renato Carlos Farinha Duarte

    2014-10-01

    Full Text Available The ability to acquire and maintain appropriate representations of time-varying, sequentialstimulus events is a fundamental feature of neocortical circuits and a necessary first step towardsmore specialized information processing. The dynamical properties of such representationsdepend on the current state of the circuit, which is determined primarily by the ongoing, internallygenerated activity, setting the ground state from which input-specific transformations emerge.Here, we begin by demonstrating that timing-dependent synaptic plasticity mechanisms havean important role to play in the active maintenance of an ongoing dynamics characterized byasynchronous and irregular firing, closely resembling cortical activity in vivo. Incoming stimuli,acting as perturbations of the local balance of excitation and inhibition, require fast adaptiveresponses to prevent the development of unstable activity regimes, such as those characterizedby a high degree of population-wide synchrony. We establish a link between such pathologicalnetwork activity, which is circumvented by the action of plasticity, and a reduced computationalcapacity. Additionally, we demonstrate that the action of plasticity shapes and stabilizes thetransient network states exhibited in the presence of sequentially presented stimulus events,allowing the development of adequate and discernible stimulus representations. The mainfeature responsible for the increased discriminability of stimulus-driven population responsesin plastic networks is shown to be the decorrelating action of inhibitory plasticity and theconsequent maintenance of the asynchronous irregular dynamic regime both for ongoing activityand stimulus-driven responses, whereas excitatory plasticity is shown to play only a marginalrole.

  3. How lateral connections and spiking dynamics may separate multiple objects moving together.

    Directory of Open Access Journals (Sweden)

    Benjamin D Evans

    Full Text Available Over successive stages, the ventral visual system of the primate brain develops neurons that respond selectively to particular objects or faces with translation, size and view invariance. The powerful neural representations found in Inferotemporal cortex form a remarkably rapid and robust basis for object recognition which belies the difficulties faced by the system when learning in natural visual environments. A central issue in understanding the process of biological object recognition is how these neurons learn to form separate representations of objects from complex visual scenes composed of multiple objects. We show how a one-layer competitive network comprised of 'spiking' neurons is able to learn separate transformation-invariant representations (exemplified by one-dimensional translations of visual objects that are always seen together moving in lock-step, but separated in space. This is achieved by combining 'Mexican hat' functional lateral connectivity with cell firing-rate adaptation to temporally segment input representations of competing stimuli through anti-phase oscillations (perceptual cycles. These spiking dynamics are quickly and reliably generated, enabling selective modification of the feed-forward connections to neurons in the next layer through Spike-Time-Dependent Plasticity (STDP, resulting in separate translation-invariant representations of each stimulus. Variations in key properties of the model are investigated with respect to the network's ability to develop appropriate input representations and subsequently output representations through STDP. Contrary to earlier rate-coded models of this learning process, this work shows how spiking neural networks may learn about more than one stimulus together without suffering from the 'superposition catastrophe'. We take these results to suggest that spiking dynamics are key to understanding biological visual object recognition.

  4. How Fast Do Objects Fall in Visual Memory? Uncovering the Temporal and Spatial Features of Representational Gravity.

    Science.gov (United States)

    De Sá Teixeira, Nuno

    2016-01-01

    Visual memory for the spatial location where a moving target vanishes has been found to be systematically displaced downward in the direction of gravity. Moreover, it was recently reported that the magnitude of the downward error increases steadily with increasing retention intervals imposed after object's offset and before observers are allowed to perform the spatial localization task, in a pattern where the remembered vanishing location drifts downward as if following a falling trajectory. This outcome was taken to reflect the dynamics of a representational model of earth's gravity. The present study aims to establish the spatial and temporal features of this downward drift by taking into account the dynamics of the motor response. The obtained results show that the memory for the last location of the target drifts downward with time, thus replicating previous results. Moreover, the time taken for completion of the behavioural localization movements seems to add to the imposed retention intervals in determining the temporal frame during which the visual memory is updated. Overall, it is reported that the representation of spatial location drifts downward by about 3 pixels for each two-fold increase of time until response. The outcomes are discussed in relation to a predictive internal model of gravity which outputs an on-line spatial update of remembered objects' location.

  5. Effectiveness of Occluded Object Representations at Displaying Ordinal Depth Information in Augmented Reality

    Science.gov (United States)

    2013-03-01

    Displaying Ordinal Depth Information in Augmented Reality 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT...Effectiveness of Occluded Object Representations at Displaying Ordinal Depth Information in Augmented Reality Mark A. Livingston∗ Naval Research Laboratory...effectively impossible with all icon styles, whereas in the case of partial overlap, the Ground Plane had a clear advantage. Keywords: Augmented reality , human

  6. Quantum processes, space-time representation and brain dynamics

    CERN Document Server

    Roy, Sisir; Roy, Sisir; Kafatos, Menas

    2003-01-01

    The recent controversy of applicability of quantum formalism to brain dynamics has been critically analysed. The prerequisites for any type of quantum formalism or quantum field theory is to investigate whether the anatomical structure of brain permits any kind of smooth geometric notion like Hilbert structure or four dimensional Minkowskian structure for quantum field theory. The present understanding of brain function clearly denies any kind of space-time representation in Minkowskian sense. However, three dimensional space and one time can be assigned to the neuromanifold and the concept of probabilistic geometry is shown to be appropriate framework to understand the brain dynamics. The possibility of quantum structure is also discussed in this framework.

  7. The Neural Representation of 3-Dimensional Objects in Rodent Memory Circuits

    Science.gov (United States)

    Burke, Sara N.; Barnes, Carol A.

    2014-01-01

    Three-dimensional objects are common stimuli that rodents and other animals encounter in the natural world that contribute to the associations that are the hallmark of explicit memory. Thus, the use of 3-dimensional objects for investigating the circuits that support associative and episodic memories has a long history. In rodents, the neural representation of these types of stimuli is a polymodal process and lesion data suggest that the perirhinal cortex, an area of the medial temporal lobe that receives afferent input from all sensory modalities, is particularly important for integrating sensory information across modalities to support object recognition. Not surprisingly, recent data from in vivo electrophysiological recordings have shown that principal cells within the perirhinal cortex are activated at locations of an environment that contain 3-dimensional objects. Interestingly, it appears that neural activity patterns related to object stimuli are ubiquitous across memory circuits and have now been observed in many medial temporal lobe structures as well as in the anterior cingulate cortex. This review summarizes behavioral and neurophysiological data that examine the representation of 3-dimensional objects across brain regions that are involved in memory. PMID:25205370

  8. Making the invisible visible: Enhancing students' conceptual understanding by introducing representations of abstract objects in a simulation

    NARCIS (Netherlands)

    Olympiou, G.; Zacharias, Z.; Jong, de T.

    2013-01-01

    This study aimed to identify if complementing representations of concrete objects with representations of abstract objects improves students’ conceptual understanding as they use a simulation to experiment in the domain of Light and Color. Moreover, we investigated whether students’ prior knowledge

  9. Making the invisible visible: Enhancing students' conceptual understanding by introducing representations of abstract objects in a simulation

    NARCIS (Netherlands)

    Olympiou, G.; Zacharias, Z.; de Jong, Anthonius J.M.

    2013-01-01

    This study aimed to identify if complementing representations of concrete objects with representations of abstract objects improves students’ conceptual understanding as they use a simulation to experiment in the domain of Light and Color. Moreover, we investigated whether students’ prior knowledge

  10. Linking somatic and symbolic representation in semantic memory: the dynamic multilevel reactivation framework.

    Science.gov (United States)

    Reilly, Jamie; Peelle, Jonathan E; Garcia, Amanda; Crutch, Sebastian J

    2016-08-01

    Biological plausibility is an essential constraint for any viable model of semantic memory. Yet, we have only the most rudimentary understanding of how the human brain conducts abstract symbolic transformations that underlie word and object meaning. Neuroscience has evolved a sophisticated arsenal of techniques for elucidating the architecture of conceptual representation. Nevertheless, theoretical convergence remains elusive. Here we describe several contrastive approaches to the organization of semantic knowledge, and in turn we offer our own perspective on two recurring questions in semantic memory research: (1) to what extent are conceptual representations mediated by sensorimotor knowledge (i.e., to what degree is semantic memory embodied)? (2) How might an embodied semantic system represent abstract concepts such as modularity, symbol, or proposition? To address these questions, we review the merits of sensorimotor (i.e., embodied) and amodal (i.e., disembodied) semantic theories and address the neurobiological constraints underlying each. We conclude that the shortcomings of both perspectives in their extreme forms necessitate a hybrid middle ground. We accordingly propose the Dynamic Multilevel Reactivation Framework-an integrative model predicated upon flexible interplay between sensorimotor and amodal symbolic representations mediated by multiple cortical hubs. We discuss applications of the dynamic multilevel reactivation framework to abstract and concrete concept representation and describe how a multidimensional conceptual topography based on emotion, sensation, and magnitude can successfully frame a semantic space containing meanings for both abstract and concrete words. The consideration of 'abstract conceptual features' does not diminish the role of logical and/or executive processing in activating, manipulating and using information stored in conceptual representations. Rather, it proposes that the materials upon which these processes operate

  11. The role of surface-based representations of shape in visual object recognition.

    Science.gov (United States)

    Reppa, Irene; Greville, W James; Leek, E Charles

    2015-01-01

    This study contrasted the role of surfaces and volumetric shape primitives in three-dimensional object recognition. Observers (N = 50) matched subsets of closed contour fragments, surfaces, or volumetric parts to whole novel objects during a whole-part matching task. Three factors were further manipulated: part viewpoint (either same or different between component parts and whole objects), surface occlusion (comparison parts contained either visible surfaces only, or a surface that was fully or partially occluded in the whole object), and target-distractor similarity. Similarity was varied in terms of systematic variation in nonaccidental (NAP) or metric (MP) properties of individual parts. Analysis of sensitivity (d') showed a whole-part matching advantage for surface-based parts and volumes over closed contour fragments--but no benefit for volumetric parts over surfaces. We also found a performance cost in matching volumetric parts to wholes when the volumes showed surfaces that were occluded in the whole object. The same pattern was found for both same and different viewpoints, and regardless of target-distractor similarity. These findings challenge models in which recognition is mediated by volumetric part-based shape representations. Instead, we argue that the results are consistent with a surface-based model of high-level shape representation for recognition.

  12. Neural representation of ambiguous visual objects in the inferior temporal cortex.

    Directory of Open Access Journals (Sweden)

    Nazli Emadi

    Full Text Available Inferior temporal (IT cortex as the final stage of the ventral visual pathway is involved in visual object recognition. In our everyday life we need to recognize visual objects that are degraded by noise. Psychophysical studies have shown that the accuracy and speed of the object recognition decreases as the amount of visual noise increases. However, the neural representation of ambiguous visual objects and the underlying neural mechanisms of such changes in the behavior are not known. Here, by recording the neuronal spiking activity of macaque monkeys' IT we explored the relationship between stimulus ambiguity and the IT neural activity. We found smaller amplitude, later onset, earlier offset and shorter duration of the response as visual ambiguity increased. All of these modulations were gradual and correlated with the level of stimulus ambiguity. We found that while category selectivity of IT neurons decreased with noise, it was preserved for a large extent of visual ambiguity. This noise tolerance for category selectivity in IT was lost at 60% noise level. Interestingly, while the response of the IT neurons to visual stimuli at 60% noise level was significantly larger than their baseline activity and full (100% noise, it was not category selective anymore. The latter finding shows a neural representation that signals the presence of visual stimulus without signaling what it is. In general these findings, in the context of a drift diffusion model, explain the neural mechanisms of perceptual accuracy and speed changes in the process of recognizing ambiguous objects.

  13. Neural representation of ambiguous visual objects in the inferior temporal cortex.

    Science.gov (United States)

    Emadi, Nazli; Esteky, Hossein

    2013-01-01

    Inferior temporal (IT) cortex as the final stage of the ventral visual pathway is involved in visual object recognition. In our everyday life we need to recognize visual objects that are degraded by noise. Psychophysical studies have shown that the accuracy and speed of the object recognition decreases as the amount of visual noise increases. However, the neural representation of ambiguous visual objects and the underlying neural mechanisms of such changes in the behavior are not known. Here, by recording the neuronal spiking activity of macaque monkeys' IT we explored the relationship between stimulus ambiguity and the IT neural activity. We found smaller amplitude, later onset, earlier offset and shorter duration of the response as visual ambiguity increased. All of these modulations were gradual and correlated with the level of stimulus ambiguity. We found that while category selectivity of IT neurons decreased with noise, it was preserved for a large extent of visual ambiguity. This noise tolerance for category selectivity in IT was lost at 60% noise level. Interestingly, while the response of the IT neurons to visual stimuli at 60% noise level was significantly larger than their baseline activity and full (100%) noise, it was not category selective anymore. The latter finding shows a neural representation that signals the presence of visual stimulus without signaling what it is. In general these findings, in the context of a drift diffusion model, explain the neural mechanisms of perceptual accuracy and speed changes in the process of recognizing ambiguous objects.

  14. The Representation of Objects in Apraxia: From Action Execution to Error Awareness.

    Science.gov (United States)

    Canzano, Loredana; Scandola, Michele; Gobbetto, Valeria; Moretto, Giuseppe; D'Imperio, Daniela; Moro, Valentina

    2016-01-01

    Apraxia is a well-known syndrome characterized by the sufferer's inability to perform routine gestures. In an attempt to understand the syndrome better, various different theories have been developed and a number of classifications of different subtypes have been proposed. In this article review, we will address these theories with a specific focus on how the use of objects helps us to better understand upper limb apraxia. With this aim, we will consider transitive vs. intransitive action dissociation as well as less frequent types of apraxia involving objects, i.e., constructive apraxia and magnetic apraxia. Pantomime and the imitation of objects in use are also considered with a view to dissociating the various different components involved in upper limb apraxia. Finally, we discuss the evidence relating to action recognition and awareness of errors in the execution of actions. Various different components concerning the use of objects emerge from our analysis and the results show that knowledge of an object and sensory-motor representations are supported by other functions such as spatial and body representations, executive functions and monitoring systems.

  15. THE REPRESENTATION OF OBJECTS IN APRAXIA: FROM ACTION EXECUTION TO ERROR AWARENESS

    Directory of Open Access Journals (Sweden)

    LOREDANA eCANZANO

    2016-02-01

    Full Text Available Apraxia is a well-known syndrome characterized by the sufferer’s inability to perform routine gestures. In an attempt to understand the syndrome better, various different theories have been developed and a number of classifications of different subtypes have been proposed. In this paper review, we will address these theories with a specific focus on how the use of objects helps us to better understand upper limb apraxia. With this aim, we will consider transitive versus intransitive action dissociation as well as less frequent types of apraxia involving objects, i.e. constructive apraxia and magnetic apraxia. Pantomime and the imitation of objects in use are also considered with a view to dissociating the various different components involved in upper limb apraxia. Finally, we discuss the evidence relating to action recognition and awareness of errors in the execution of actions. Various different components concerning the use of objects emerge from our analysis and the results show that knowledge of an object and sensory-motor representations are supported by other functions such as spatial and body representations, executive functions and monitoring systems.

  16. Structured representation of drug indications: lexical and semantic analysis and object-oriented modeling.

    Science.gov (United States)

    Duclos, C; Venot, A

    2000-03-01

    No standardized representation of drug indications is currently available that could be used in drug knowledge bases. We describe an object-oriented representation of indications that should make it possible to develop new tools for selecting drugs and checking prescriptions in computerized drug prescription systems. The model was developed using the results of a lexical and semantic analysis of drug indications, collected into a single file and processed using natural language processing software. It distinguishes both the diseases for which the drug may be given and the efficiency of the drug for a given indication. Two aspects of the model were evaluated: the differences if two independent evaluators filled the attributes independently and the loss of information induced by the use of the model. A system based on this model, making it possible for the physician to select all the drugs satisfying various criteria, is also presented.

  17. Tracking of Moving Objects in Video Through Invariant Features in Their Graph Representation

    Directory of Open Access Journals (Sweden)

    O. Miller

    2008-08-01

    Full Text Available The paper suggests a contour-based algorithm for tracking moving objects in video. The inputs are segmented moving objects. Each segmented frame is transformed into region adjacency graphs (RAGs. The object's contour is divided into subcurves. Contour's junctions are derived. These junctions are the unique “signature” of the tracked object. Junctions from two consecutive frames are matched. The junctions' motion is estimated using RAG edges in consecutive frames. Each pair of matched junctions may be connected by several paths (edges that become candidates that represent a tracked contour. These paths are obtained by the k-shortest paths algorithm between two nodes. The RAG is transformed into a weighted directed graph. The final tracked contour construction is derived by a match between edges (subcurves and candidate paths sets. The RAG constructs the tracked contour that enables an accurate and unique moving object representation. The algorithm tracks multiple objects, partially covered (occluded objects, compounded object of merge/split such as players in a soccer game and tracking in a crowded area for surveillance applications. We assume that features of topologic signature of the tracked object stay invariant in two consecutive frames. The algorithm's complexity depends on RAG's edges and not on the image's size.

  18. Tracking of Moving Objects in Video Through Invariant Features in Their Graph Representation

    Directory of Open Access Journals (Sweden)

    Averbuch A

    2008-01-01

    Full Text Available Abstract The paper suggests a contour-based algorithm for tracking moving objects in video. The inputs are segmented moving objects. Each segmented frame is transformed into region adjacency graphs (RAGs. The object's contour is divided into subcurves. Contour's junctions are derived. These junctions are the unique “signature� of the tracked object. Junctions from two consecutive frames are matched. The junctions' motion is estimated using RAG edges in consecutive frames. Each pair of matched junctions may be connected by several paths (edges that become candidates that represent a tracked contour. These paths are obtained by the -shortest paths algorithm between two nodes. The RAG is transformed into a weighted directed graph. The final tracked contour construction is derived by a match between edges (subcurves and candidate paths sets. The RAG constructs the tracked contour that enables an accurate and unique moving object representation. The algorithm tracks multiple objects, partially covered (occluded objects, compounded object of merge/split such as players in a soccer game and tracking in a crowded area for surveillance applications. We assume that features of topologic signature of the tracked object stay invariant in two consecutive frames. The algorithm's complexity depends on RAG's edges and not on the image's size.

  19. Multi-objective analysis of a component-based representation within an interactive evolutionary design system

    Science.gov (United States)

    Machwe, A. T.; Parmee, I. C.

    2007-07-01

    This article describes research relating to a user-centered evolutionary design system that evaluates both engineering and aesthetic aspects of design solutions during early-stage conceptual design. The experimental system comprises several components relating to user interaction, problem representation, evolutionary search and exploration and online learning. The main focus of the article is the evolutionary aspect of the system when using a single quantitative objective function plus subjective judgment of the user. Additionally, the manner in which the user-interaction aspect affects system output is assessed by comparing Pareto frontiers generated with and without user interaction via a multi-objective evolutionary algorithm (MOEA). A solution clustering component is also introduced and it is shown how this can improve the level of support to the designer when dealing with a complex design problem involving multiple objectives. Supporting results are from the application of the system to the design of urban furniture which, in this case, largely relates to seating design.

  20. Neurophysiology of prehension. III. Representation of object features in posterior parietal cortex of the macaque monkey.

    Science.gov (United States)

    Gardner, Esther P; Babu, K Srinivasa; Ghosh, Soumya; Sherwood, Adam; Chen, Jessie

    2007-12-01

    Neurons in posterior parietal cortex (PPC) may serve both proprioceptive and exteroceptive functions during prehension, signaling hand actions and object properties. To assess these roles, we used digital video recordings to analyze responses of 83 hand-manipulation neurons in area 5 as monkeys grasped and lifted objects that differed in shape (round and rectangular), size (large and small spheres), and location (identical rectangular blocks placed lateral and medial to the shoulder). The task contained seven stages -- approach, contact, grasp, lift, hold, lower, relax -- plus a pretrial interval. The four test objects evoked similar spike trains and mean rate profiles that rose significantly above baseline from approach through lift, with peak activity at contact. Although representation by the spike train of specific hand actions was stronger than distinctions between grasped objects, 34% of these neurons showed statistically significant effects of object properties or hand postures on firing rates. Somatosensory input from the hand played an important role as firing rates diverged most prominently on contact as grasp was secured. The small sphere -- grasped with the most flexed hand posture -- evoked the highest firing rates in 43% of the population. Twenty-one percent distinguished spheres that differed in size and weight, and 14% discriminated spheres from rectangular blocks. Location in the workspace modulated response amplitude as objects placed across the midline evoked higher firing rates than positions lateral to the shoulder. We conclude that area 5 neurons, like those in area AIP, integrate object features, hand actions, and grasp postures during prehension.

  1. Learning illumination- and orientation-invariant representations of objects through temporal association.

    Science.gov (United States)

    Wallis, Guy; Backus, Benjamin T; Langer, Michael; Huebner, Gesche; Bülthoff, Heinrich

    2009-07-10

    As the orientation or illumination of an object changes so does its appearance. This paper considers how observers are nonetheless able to recognize objects that have undergone such changes. In particular the paper tests the hypothesis that observers rely on temporal correlations between different object views to decide whether they are views of the same object or not. In a series of experiments subjects were shown a sequence of views representing a slowly transforming object. Testing revealed that subjects had formed object representations which were directly influenced by the temporal characteristics of the training views. In particular, introducing spurious correlations between views of different people's heads caused subjects to regard those views as being of a single person. This rapid and robust overriding of basic generalization processes supports the view that our recognition system tracks the correlated appearance of views of objects across time. Such view associations appear to allow the visual system to solve the view invariance problem without recourse to complex illumination models for extracting 3D form, or the use of the image plane transformations required to make appearance-based comparisons.

  2. Brain representation of object-centered space in monkeys and humans.

    Science.gov (United States)

    Olson, Carl R

    2003-01-01

    Visuospatial cognition requires taking into account where things are relative to each other and not just relative to the viewer. Consequently it would make sense for the brain to form an explicit representation of object-centered and not just of ego-centered space. Evidence bearing on the presence and nature of neural maps of object-centered space has come from two sources: single-neuron recording in behaving monkeys and assessment of the visual abilities of human patients with hemispatial neglect. Studies of the supplementary eye field of the monkey have revealed that it contains neurons with object-centered spatial selectivity. These neurons fire when the monkey has selected, as target for an eye movement or attention, a particular location defined relative to a reference object. Studies of neglect have revealed that in some patients the condition is expressed with respect to an object-centered and object-aligned reference frame. These patients neglect one side of an object, as defined relative to its intrinsic midline, regardless of its location and orientation relative to the viewer. The two sets of observations are complementary in the sense that the loss of neurons, such as observed in the monkey, could explain the spatial distribution of neglect in these patients.

  3. Extrinsic reference frames modify the neural substrates of object-location representations.

    Science.gov (United States)

    Chan, Edgar; Baumann, Oliver; Bellgrove, Mark A; Mattingley, Jason B

    2013-04-01

    The ability to form spatial representations of object locations is an important component of successful spatial navigation. Evidence from behavioral studies suggests that environmental features that have a salient coordinate axis (e.g., a rectangular building or a geometrical room) may provide a reference frame for the encoding of object-location information. Here we used functional magnetic resonance imaging (fMRI) to determine the brain networks engaged when object-location representations are stored with respect to an extrinsic reference frame. Participants learned the layout of an object array in an active, virtual-navigation paradigm. A square mat positioned on the floor of the virtual arena acted as the extrinsic reference frame. Knowledge of the spatial arrangement of the object array was probed while participants underwent fMRI, using a spatial judgment task that required them to imagine orientations of the learned array that were either aligned or misaligned with the geometry of the mat. Consistent with previous findings, participants responded faster and were more accurate when the imagined orientation was aligned, as opposed to misaligned, with the extrinsic reference frame. Analysis of the fMRI data revealed important differences in brain activity between the two conditions. Significantly greater activity was observed in the aligned condition compared with the misaligned condition across a bilateral network of brain areas that included the inferior occipital gyri, inferior and middle temporal gyri, and fusiform gyri. By contrast, activity in the misaligned condition was significantly greater than in the aligned condition in bilateral dorsolateral prefrontal and anterior cingulate cortex, and in the right anterior prefrontal and anterior insular cortex. These results suggest that retrieval of spatial locations that are aligned with an extrinsic reference frame involve direct access to detailed and accurate representations within the ventral visual

  4. Neural Dynamics and Information Representation in Microcircuits of Motor Cortex

    Directory of Open Access Journals (Sweden)

    Yasuhiro eTsubo

    2013-05-01

    Full Text Available The brain has to analyze and respond to external events that can change rapidly from time to time, suggesting that information processing by the brain may be essentially dynamic rather than static. The dynamical features of neural computation are of significant importance in motor cortex that governs the process of movement generation and learning. In this paper, we discuss these features based primarily on our recent findings on neural dynamics and information coding in the microcircuit of rat motor cortex. In fact, cortical neurons show a variety of dynamical behavior from rhythmic activity in various frequency bands to highly irregular spike firing. Of particular interest are the similarity and dissimilarity of the neuronal response properties in different layers of motor cortex. By conducting electrophysiological recordings in slice preparation, we report the phase response curves of neurons in different cortical layers to demonstrate their layer-dependent synchronization properties. We then study how motor cortex recruits task-related neurons in different layers for voluntary arm movements by simultaneous juxtacellular and multiunit recordings from behaving rats. The results suggest an interesting difference in the spectrum of functional activity between the superficial and deep layers. Furthermore, the task-related activities recorded from various layers exhibited power law distributions of inter-spike intervals (ISIs, in contrast to a general belief that ISIs obey Poisson or Gamma distributions in cortical neurons. We present a theoretical argument that this power law of in vivo neurons may represent the maximization of the entropy of firing rate with limited energy consumption of spike generation. Though further studies are required to fully clarify the functional implications of this coding principle, it may shed new light on information representations by neurons and circuits in motor cortex.

  5. Space-dependent representation of objects and other's action in monkey ventral premotor grasping neurons.

    Science.gov (United States)

    Bonini, Luca; Maranesi, Monica; Livi, Alessandro; Fogassi, Leonardo; Rizzolatti, Giacomo

    2014-03-12

    The macaque ventral premotor area F5 hosts two types of visuomotor grasping neurons: "canonical" neurons, which respond to visually presented objects and underlie visuomotor transformation for grasping, and "mirror" neurons, which respond during the observation of others' action, likely playing a role in action understanding. Some previous evidence suggested that canonical and mirror neurons could be anatomically segregated in different sectors of area F5. Here we investigated the functional properties of single neurons in the hand field of area F5 using various tasks similar to those originally designed to investigate visual responses to objects and actions. By using linear multielectrode probes, we were able to simultaneously record different types of neurons and to precisely localize their cortical depth. We recorded 464 neurons, of which 243 showed visuomotor properties. Canonical and mirror neurons were often present in the same cortical sites; and, most interestingly, a set of neurons showed both canonical and mirror properties, discharging to object presentation as well as during the observation of experimenter's goal-directed acts (canonical-mirror neurons). Typically, visual responses to objects were constrained to the monkey peripersonal space, whereas action observation responses were less space-selective. Control experiments showed that space-constrained coding of objects mostly relies on an operational (action possibility) rather than metric (absolute distance) reference frame. Interestingly, canonical-mirror neurons appear to code object as target for both one's own and other's action, suggesting that they could play a role in predictive representation of others' impending actions.

  6. Learning representations for object classification using multi-stage optimal component analysis.

    Science.gov (United States)

    Wu, Yiming; Liu, Xiuwen; Mio, Washington

    2008-01-01

    Learning data representations is a fundamental challenge in modeling neural processes and plays an important role in applications such as object recognition. Optimal component analysis (OCA) formulates the problem in the framework of optimization on a Grassmann manifold and a stochastic gradient method is used to estimate the optimal basis. OCA has been successfully applied to image classification problems arising in a variety of contexts. However, as the search space is typically very high dimensional, OCA optimization often requires expensive computational cost. In multi-stage OCA, we first hierarchically project the data onto several low-dimensional subspaces using standard techniques, then OCA learning is performed hierarchically from the lowest to the highest levels to learn about a subspace that is optimal for data discrimination based on the K-nearest neighbor classifier. One of the main advantages of multi-stage OCA lies in the fact that it greatly improves the computational efficiency of the OCA learning algorithm without sacrificing the recognition performance, thus enhancing its applicability to practical problems. In addition to the nearest neighbor classifier, we illustrate the effectiveness of the learned representations on object classification used in conjunction with classifiers such as neural networks and support vector machines.

  7. A preoccupation with object-representation: the Beckett-Bion case revisited.

    Science.gov (United States)

    Oppenheim, L

    2001-08-01

    Taking issue with the notion of a profound reciprocal influence of Samuel Beckett and his analyst, Wilfred Bion, based on supposition all too often passed as fact, the author refutes the idea that Bion's 'Attacks on linking' was based on his later-to-be famous patient. Choosing, rather, to apply Bion's concepts of transformation and assaults on verbal thought to Beckett's remarkably visual and highly dissociative writing, she finds in the analyst's work a means of exploring a startling preoccupation with object representation and an anxiety of remembrance constant throughout the writer's texts. Is this fixation attributable only to aesthetic strategy or does it say something about the writer's own inner representational world? Relating the writer's obsession to Bion's concepts and, moreover, its dissociative expression to the decathexis and blank mourning explored by Green, she uncovers within it a reflection of the kind of evocative memory disturbance identified with primary dyadic dysfunction. This application of Bion and Green to Beckett veers distinctly less towards psychohistory, however, than to how sublimation has rendered this object-relational failure an aesthetic success.

  8. A fisher vector representation of GPR data for detecting buried objects

    Science.gov (United States)

    Karem, Andrew; Khalifa, Amine B.; Frigui, Hichem

    2016-05-01

    We present a new method, based on the Fisher Vector (FV), for detecting buried explosive objects using ground- penetrating radar (GPR) data. First, low-level dense SIFT features are extracted from a grid covering a region of interest (ROIs). ROIs are identified as regions with high-energy along the (down-track, depth) dimensions of the 3-D GPR cube, or with high-energy along the (cross-track, depth) dimensions. Next, we model the training data (in the SIFT feature space) by a mixture of Gaussian components. Then, we construct FV descriptors based on the Fisher Kernel. The Fisher Kernel characterizes low-level features from an ROI by their deviation from a generative model. The deviation is the gradient of the ROI log-likelihood with respect to the generative model parameters. The vectorial representation of all the deviations is called the Fisher Vector. FV is a generalization of the standard Bag of Words (BoW) method, which provides a framework to map a set of local descriptors to a global feature vector. It is more efficient to compute than the BoW since it relies on a significantly smaller codebook. In addition, mapping a GPR signature into one global feature vector using this technique makes it more efficient to classify using simple and fast linear classifiers such as Support Vector Machines. The proposed approach is applied to detect buried explosive objects using GPR data. The selected data were accumulated across multiple dates and multiple test sites by a vehicle mounted mine detector (VMMD) using GPR sensor. This data consist of a diverse set of conventional landmines and other buried explosive objects consisting of varying shapes, metal content, and burial depths. The performance of the proposed approach is analyzed using receiver operating characteristics (ROC) and is compared to other state-of-the-art feature representation methods.

  9. An object-oriented forest landscape model and its representation of tree species

    Science.gov (United States)

    Hong S. He; David J. Mladenoff; Joel Boeder

    1999-01-01

    LANDIS is a forest landscape model that simulates the interaction of large landscape processes and forest successional dynamics at tree species level. We discuss how object-oriented design (OOD) approaches such as modularity, abstraction and encapsulation are integrated into the design of LANDIS. We show that using OOD approaches, model decisions (olden as model...

  10. The representations underlying infants' choice of more: object files versus analog magnitudes.

    Science.gov (United States)

    Feigenson, Lisa; Carey, Susan; Hauser, Marc

    2002-03-01

    A new choice task was used to explore infants' spontaneous representations of more and less. Ten- and 12-month-old infants saw crackers placed sequentially into two containers, then were allowed to crawl and obtain the crackers from the container they chose. Infants chose the larger quantity with comparisons of 1 versus 2 and 2 versus 3, but failed with comparisons of 3 versus 4, 2 versus 4, and 3 versus 6. Success with visible arrays ruled out a motivational explanation for failure in the occluded 3-versus-6 condition. Control tasks ruled out the possibility that presentation duration guided choice, and showed that presentation complexity was not responsible for the failure with larger numbers. When crackers were different sizes, total surface area or volume determined choice. The infants 'pattern of success and failure supports the hypothesis that they relied on object-file representations, comparing mental models via total volume or surface area rather than via one-to-one correspondence between objectfiles.

  11. The (nontree-representability of syntactic objects.a graft-theoretical approach to nominal coordination

    Directory of Open Access Journals (Sweden)

    Mihaela Tănase-Dogaru

    2010-01-01

    Full Text Available The present paper deals with nominal coordination and the way Graft Theory can be applied to this domain. As introduced and defined by van Riemsdijk (1998, 2000 and 2001, Graft Theory was initially applied to the domain of syntactic amalgams (Lakoff 1974 and transparent free relative clauses. The paper claims that Graft Theory can equally apply to the domain of coordination and a range of syntactic phenomena that are associated with coordination. The main idea that this paper advances is that Graft Theory could solve the problem of syntactic representability with coordinate structures, which are known to pose serious difficulties for binary branching. By endorsing the main tenets of Graft Theory, the paper also touches upon an issue with far-reaching implications: the (impossibility of representing certain syntactic objects as syntactic trees.

  12. Object Oriented Programming Systems (OOPS) and frame representations: An investigation of programming paradigms

    Science.gov (United States)

    Auty, David

    1988-01-01

    The project was initiated to research Object Oriented Programming Systems (OOPS) and frame representation systems, their significance and applicability, and their implementation in or relationship to Ada. Object orientated is currently a very popular conceptual adjective. Object oriented programming, in particular, is promoted as a particularly productive approach to programming; an approach which maximizes opportunities for code reuse and lends itself to the definition of convenient and well-developed units. Such units are thus expected to be usable in a variety of situations, beyond the typical highly specific unit development of other approaches. Frame represenation systems share a common heritage and similar conceptual foundations. Together they represent a quickly emerging alternative approach to programming. The approach is to first define the terms, starting with relevant concepts and using these to put bounds on what is meant by OOPS and Frames. From this the possibilities were pursued to merge OOPS with Ada which will further elucidate the significant characteristics which make up this programming approach. Finally, some of the merits and demerits of OOPS were briefly considered as a way of addressing the applicability of OOPS to various programming tasks.

  13. Dynamic object management for distributed data structures

    Science.gov (United States)

    Totty, Brian K.; Reed, Daniel A.

    1992-01-01

    In distributed-memory multiprocessors, remote memory accesses incur larger delays than local accesses. Hence, insightful allocation and access of distributed data can yield substantial performance gains. The authors argue for the use of dynamic data management policies encapsulated within individual distributed data structures. Distributed data structures offer performance, flexibility, abstraction, and system independence. This approach is supported by data from a trace-driven simulation study of parallel scientific benchmarks. Experimental data on memory locality, message count, message volume, and communication delay suggest that data-structure-specific data management is superior to a single, system-imposed policy.

  14. Balancing Exploration, Uncertainty Representation and Computational Time in Many-Objective Reservoir Policy Optimization

    Science.gov (United States)

    Zatarain-Salazar, J.; Reed, P. M.; Quinn, J.; Giuliani, M.; Castelletti, A.

    2016-12-01

    As we confront the challenges of managing river basin systems with a large number of reservoirs and increasingly uncertain tradeoffs impacting their operations (due to, e.g. climate change, changing energy markets, population pressures, ecosystem services, etc.), evolutionary many-objective direct policy search (EMODPS) solution strategies will need to address the computational demands associated with simulating more uncertainties and therefore optimizing over increasingly noisy objective evaluations. Diagnostic assessments of state-of-the-art many-objective evolutionary algorithms (MOEAs) to support EMODPS have highlighted that search time (or number of function evaluations) and auto-adaptive search are key features for successful optimization. Furthermore, auto-adaptive MOEA search operators are themselves sensitive to having a sufficient number of function evaluations to learn successful strategies for exploring complex spaces and for escaping from local optima when stagnation is detected. Fortunately, recent parallel developments allow coordinated runs that enhance auto-adaptive algorithmic learning and can handle scalable and reliable search with limited wall-clock time, but at the expense of the total number of function evaluations. In this study, we analyze this tradeoff between parallel coordination and depth of search using different parallelization schemes of the Multi-Master Borg on a many-objective stochastic control problem. We also consider the tradeoff between better representing uncertainty in the stochastic optimization, and simplifying this representation to shorten the function evaluation time and allow for greater search. Our analysis focuses on the Lower Susquehanna River Basin (LSRB) system where multiple competing objectives for hydropower production, urban water supply, recreation and environmental flows need to be balanced. Our results provide guidance for balancing exploration, uncertainty, and computational demands when using the EMODPS

  15. Geometric Representation of Interacting Non-Relativistic Open Strings using Extended Objects

    CERN Document Server

    Arias, P J; Fuenmayor, E; Leal, L

    2013-01-01

    Non-relativistic charged open strings coupled with Abelian gauge fields are quantized in a geometric representation that generalizes the Loop Representation. The model consists of open-strings interacting through a Kalb-Ramond field in four dimensions. The geometric representation proposed uses lines and surfaces that can be interpreted as an extension of the picture of Faraday's lines of classical electromagnetism. This representation results to be consistent, provided the coupling constant (the "charge" of the string) is quantized. The Schr\\"odinger equation in this representation is also presented.

  16. Converting an integrated hospital formulary into an object-oriented database representation.

    Science.gov (United States)

    Gu, H; Liu, L M; Halper, M; Geller, J; Perl, Y

    1998-01-01

    Controlled Medical Vocabularies (CMVs) have proven to be extremely useful in their support of the tasks of information sharing and integration, communication among various software applications, and decision support. Modeling a CMV as an Object-Oriented Database (OODB) provides additional benefits such as increased support for vocabulary comprehension and flexible access. In this paper, we describe the process of modeling and converting an existing integrated hospital formulary (i.e., set of pharmacological concepts) into an equivalent OODB representation, which, in general, we refer to as an Object-Oriented Healthcare Vocabulary Repository (OOHVR). The source for our example OOHVR is a formulary provided by the Connecticut Healthcare Research and Education Foundation (CHREF). Utilizing this source formulary together with the semantic hierarchy composed of major and minor drug classes defined as part of the National Drug Code (NDC) directory, we constructed a CMV that was eventually converted into its OOHVR form (the CHREF-OOHVR). The actual conversion step was carried out automatically by a program, called the OOHVR Generator, that we have developed. At present, the CHREF-OOHVR is running on top of ONTOS, a commercial OODB management system, and is accessible on the Web.

  17. Reinforced AdaBoost learning for object detection with local pattern representations.

    Science.gov (United States)

    Lee, Younghyun; Han, David K; Ko, Hanseok

    2013-01-01

    A reinforced AdaBoost learning algorithm is proposed for object detection with local pattern representations. In implementing AdaBoost learning, the proposed algorithm employs an exponential criterion as a cost function and Newton's method for its optimization. In particular, we introduce an optimal selection of weak classifiers minimizing the cost function and derive the reinforced predictions based on a judicial confidence estimate to determine the classification results. The weak classifier of the proposed method produces real-valued predictions while that of the conventional AdaBoost method produces integer valued predictions of +1 or -1. Hence, in the conventional learning algorithms, the entire sample weights are updated by the same rate. On the contrary, the proposed learning algorithm allows the sample weights to be updated individually depending on the confidence level of each weak classifier prediction, thereby reducing the number of weak classifier iterations for convergence. Experimental classification performance on human face and license plate images confirm that the proposed method requires smaller number of weak classifiers than the conventional learning algorithm, resulting in higher learning and faster classification rates. An object detector implemented based on the proposed learning algorithm yields better performance in field tests in terms of higher detection rate with lower false positives than that of the conventional learning algorithm.

  18. Representations in Dynamical Embodied Agents: Re-Analyzing a Minimally Cognitive Model Agent

    Science.gov (United States)

    Mirolli, Marco

    2012-01-01

    Understanding the role of "representations" in cognitive science is a fundamental problem facing the emerging framework of embodied, situated, dynamical cognition. To make progress, I follow the approach proposed by an influential representational skeptic, Randall Beer: building artificial agents capable of minimally cognitive behaviors and…

  19. Method of Dynamic Knowledge Representation and Learning Based on Fuzzy Petri Nets

    Institute of Scientific and Technical Information of China (English)

    WEI Sheng-jun; HU Chang-zhen; SUN Ming-qian

    2008-01-01

    A method of knowledge representation and learning based on fuzzy Petri nets was designed. In this way the parameters of weights, threshold value and certainty factor in knowledge model can be adjusted dynamically. The advantages of knowledge representation based on production rules and neural networks were integrated into this method. Just as production knowledge representation, this method has clear structure and specific parameters meaning. In addition, it has learning and parallel reasoning ability as neural networks knowledge representation does. The result of simulation shows that the learning algorithm can converge, and the parameters of weights, threshold value and certainty factor can reach the ideal level after training.

  20. Implicit encoding of extrinsic object properties in stored representations mediating recognition: evidence from shadow-specific repetition priming.

    Science.gov (United States)

    Leek, E Charles; Davitt, Lina I; Cristino, Filipe

    2015-03-01

    This study investigated whether, and under what conditions, stored shape representations mediating recognition encode extrinsic object properties that vary according to viewing conditions. This was examined in relation to cast shadow. Observers (N = 90) first memorised a subset of 3D multi-part novel objects from a limited range of viewpoints rendered with either no shadow, object internal shadow, or both object internal and external (ground) plane shadow. During a subsequent test phase previously memorised targets were discriminated from visually similar distractors across learned and novel views following brief presentation of a same-shape masked prime. The primes contained either matching or mismatching shadow rendering from the training condition. The results showed a recognition advantage for objects memorised with object internal shadow. In addition, objects encoded with internal shadow were primed more strongly by matching internal shadow primes, than by same shape primes with either no shadow or both object internal and external (ground) shadow. This pattern of priming effects generalises to previously unseen views of targets rendered with object internal shadow. The results suggest that the object recognition system contains a level of stored representation at which shape and the extrinsic object property of cast shadow are bound. We propose that this occurs when cast shadow cannot be discounted during perception on the basis of external cues to the scene lighting model.

  1. A single-rate context-dependent learning process underlies rapid adaptation to familiar object dynamics.

    Directory of Open Access Journals (Sweden)

    James N Ingram

    2011-09-01

    Full Text Available Motor learning has been extensively studied using dynamic (force-field perturbations. These induce movement errors that result in adaptive changes to the motor commands. Several state-space models have been developed to explain how trial-by-trial errors drive the progressive adaptation observed in such studies. These models have been applied to adaptation involving novel dynamics, which typically occurs over tens to hundreds of trials, and which appears to be mediated by a dual-rate adaptation process. In contrast, when manipulating objects with familiar dynamics, subjects adapt rapidly within a few trials. Here, we apply state-space models to familiar dynamics, asking whether adaptation is mediated by a single-rate or dual-rate process. Previously, we reported a task in which subjects rotate an object with known dynamics. By presenting the object at different visual orientations, adaptation was shown to be context-specific, with limited generalization to novel orientations. Here we show that a multiple-context state-space model, with a generalization function tuned to visual object orientation, can reproduce the time-course of adaptation and de-adaptation as well as the observed context-dependent behavior. In contrast to the dual-rate process associated with novel dynamics, we show that a single-rate process mediates adaptation to familiar object dynamics. The model predicts that during exposure to the object across multiple orientations, there will be a degree of independence for adaptation and de-adaptation within each context, and that the states associated with all contexts will slowly de-adapt during exposure in one particular context. We confirm these predictions in two new experiments. Results of the current study thus highlight similarities and differences in the processes engaged during exposure to novel versus familiar dynamics. In both cases, adaptation is mediated by multiple context-specific representations. In the case of familiar

  2. Dynamic Learning Objects to Teach Java Programming Language

    Science.gov (United States)

    Narasimhamurthy, Uma; Al Shawkani, Khuloud

    2010-01-01

    This article describes a model for teaching Java Programming Language through Dynamic Learning Objects. The design of the learning objects was based on effective learning design principles to help students learn the complex topic of Java Programming. Visualization was also used to facilitate the learning of the concepts. (Contains 1 figure and 2…

  3. Dynamic Learning Objects to Teach Java Programming Language

    Science.gov (United States)

    Narasimhamurthy, Uma; Al Shawkani, Khuloud

    2010-01-01

    This article describes a model for teaching Java Programming Language through Dynamic Learning Objects. The design of the learning objects was based on effective learning design principles to help students learn the complex topic of Java Programming. Visualization was also used to facilitate the learning of the concepts. (Contains 1 figure and 2…

  4. Boolean network representation of contagion dynamics during a financial crisis

    Science.gov (United States)

    Caetano, Marco Antonio Leonel; Yoneyama, Takashi

    2015-01-01

    This work presents a network model for representation of the evolution of certain patterns of economic behavior. More specifically, after representing the agents as points in a space in which each dimension associated to a relevant economic variable, their relative "motions" that can be either stationary or discordant, are coded into a boolean network. Patterns with stationary averages indicate the maintenance of status quo, whereas discordant patterns represent aggregation of new agent into the cluster or departure from the former policies. The changing patterns can be embedded into a network representation, particularly using the concept of autocatalytic boolean networks. As a case study, the economic tendencies of the BRIC countries + Argentina were studied. Although Argentina is not included in the cluster formed by BRIC countries, it tends to follow the BRIC members because of strong commercial ties.

  5. Dynamics of systems of extended bodies in monad representation

    Energy Technology Data Exchange (ETDEWEB)

    Chechin, L.M.

    1995-07-01

    A universal form proposed earlier by the author for the equations of motion is used to find a monad representation of the equations of motion of a system of N extended bodies in general relativity theory. An explicit form of the equations of motion in a fixed chronometric reference system is presented. It is shown that it differs from the known coordinate motion equations obtained by the Fock method.

  6. Adaptive representation for dynamic environment, vehicle, and mission complexity

    Science.gov (United States)

    Collier, Jack A.; Ricard, Benoit; Digney, Bruce L.; Cheng, David; Trentini, Michael; Beckman, Blake

    2004-09-01

    In order for an Unmanned Ground Vehicle (UGV) to operate effectively it must be able to perceive its environment in an accurate, robust and effective manner. This is done by creating a world representation which encompasses all the perceptual information necessary for the UGV to understand its surroundings. These perceptual needs are a function of the robots mobility characteristics, the complexity of the environment in which it operates, and the mission with which the UGV has been tasked. Most perceptual systems are designed with predefined vehicle, environmental, and mission complexity in mind. This can lead the robot to fail when it encounters a situation which it was not designed for since its internal representation is insufficient for effective navigation. This paper presents a research framework currently being investigated by Defence R&D Canada (DRDC), which will ultimately relieve robotic vehicles of this problem by allowing the UGV to recognize representational deficiencies, and change its perceptual strategy to alleviate these deficiencies. This will allow the UGV to move in and out of a wide variety of environments, such as outdoor rural to indoor urban, at run time without reprogramming. We present sensor and perception work currently being done and outline our research in this area for the future.

  7. 2D-dynamic representation of DNA sequences as a graphical tool in bioinformatics

    Science.gov (United States)

    Bielińska-Wa̧Ż, D.; Wa̧Ż, P.

    2016-10-01

    2D-dynamic representation of DNA sequences is briefly reviewed. Some new examples of 2D-dynamic graphs which are the graphical tool of the method are shown. Using the examples of the complete genome sequences of the Zika virus it is shown that the present method can be applied for the study of the evolution of viral genomes.

  8. Designing as Construction of Representations: A Dynamic Viewpoint in Cognitive Design Research

    CERN Document Server

    Visser, Willemien

    2006-01-01

    This article presents a cognitively oriented viewpoint on design. It focuses on cognitive, dynamic aspects of real design, i.e., the actual cognitive activity implemented by designers during their work on professional design projects. Rather than conceiving de-signing as problem solving - Simon's symbolic information processing (SIP) approach - or as a reflective practice or some other form of situated activity - the situativity (SIT) approach - we consider that, from a cognitive viewpoint, designing is most appropriately characterised as a construction of representations. After a critical discussion of the SIP and SIT approaches to design, we present our view-point. This presentation concerns the evolving nature of representations regarding levels of abstraction and degrees of precision, the function of external representations, and specific qualities of representation in collective design. Designing is described at three levels: the organisation of the activity, its strategies, and its design-representation...

  9. Interactive Structure (EUCLID) For Static And Dynamic Representation Of Human Body

    Science.gov (United States)

    Renaud, Ch.; Steck, R.

    1983-07-01

    A specific software (EUCLID) for static and dynamic representation of human models is described. The data processing system is connected with ERGODATA and used in interactive mode by intrinsic or specific functions. More or less complex representations in 3-D view of models of the human body are developed. Biostereometric and conventional anthropometric raw data from the data bank are processed for different applications in ergonomy.

  10. The dynamical Yang-Baxter equation, representation theory, and quantum integrable systems

    CERN Document Server

    Etingof, Pavel

    2005-01-01

    The text is based on an established graduate course given at MIT that provides an introduction to the theory of the dynamical Yang-Baxter equation and its applications, which is an important area in representation theory and quantum groups. The book, which contains many detailed proofs and explicit calculations, will be accessible to graduate students of mathematics, who are familiar with the basics of representation theory of semisimple Lie algebras.

  11. Wentzel-Kramers-Brillouin Approximation for Dynamic Systems with Kinetic Coupling in Entangled State Representations

    Institute of Scientific and Technical Information of China (English)

    范洪义

    2002-01-01

    We study the Wentzel-Kramers-Brillouin (WKB) approximation for dynamic systems with kinetic couplings inentangled state representations. The result shows that the kinetic coupling will affect the position of classicalturning points where the condition of using the WKB approximation breaks down. The modified WKB approx-imation formula is derived in the entangled state representation, for example, the common eigenvector of therelative coordinate and the total momentum of two particles. The corresponding Bohr-Sommerfeld quantizationrule is also derived.

  12. Solution Representations and Local Search for the bi-objective Inventory Routing Problem

    CERN Document Server

    Barthélemy, Thibaut; Sevaux, Marc

    2012-01-01

    The solution of the biobjective IRP is rather challenging, even for metaheuristics. We are still lacking a profound understanding of appropriate solution representations and effective neighborhood structures. Clearly, both the delivery volumes and the routing aspects of the alternatives need to be reflected in an encoding, and must be modified when searching by means of local search. Our work contributes to the better understanding of such solution representations. On the basis of an experimental investigation, the advantages and drawbacks of two encodings are studied and compared.

  13. IMPLICIT REPRESENTATION FOR THE MODELLING OF HYBRID DYNAMIC SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Hybrid systems can be represented by a discrete event model interacting with a continuous model, and the interface by ideal switching components which modify the topology of a system at the switching time. This paper deals with the modelling of such systems using the bond graph approach. The paper shows the interest of the implicit representation: to derive a unique state equation with jumping parameters, to derive the implicit state equation with index of nilpotency one corresponding to each configuration, to analyze the properties of those models and to compute the discontinuity.

  14. Knowledge representation and rule-based solution system for dynamic programming model

    Institute of Scientific and Technical Information of China (English)

    胡祥培; 王旭茵

    2003-01-01

    A knowledge representation has been proposed using the state-space theory of Artificial Intelligencefor Dynamic Programming Model, in which a model can be defined as a six-tuple M = (I,G,O,T,D,S). Abuilding block modeling method uses the modules of a six-tuple to form a rule-based solution model. Moreover,a rule-based system has been designed and set up to solve the Dynamic Programming Model. This knowledge-based representation can be easily used to express symbolical knowledge and dynamic characteristics for Dynam-ic Programming Model, and the inference based on the knowledge in the process of solving Dynamic Program-ming Model can also be conveniently realized in computer.

  15. Press to grasp: how action dynamics shape object categorization.

    Science.gov (United States)

    Triberti, Stefano; Repetto, Claudia; Costantini, Marcello; Riva, Giuseppe; Sinigaglia, Corrado

    2016-03-01

    Action and object are deeply linked to each other. Not only can viewing an object influence an ongoing action, but motor representations of action can also influence visual categorization of objects. It is tempting to assume that this influence is effector-specific. However, there is indirect evidence suggesting that this influence may be related to the action goal and not just to the effector involved in achieving it. This paper aimed, for the first time, to tackle this issue directly. Participants were asked to categorize different objects in terms of the effector (e.g. hand or foot) typically used to act upon them. The task was delivered before and after a training session in which participants were instructed either just to press a pedal with their foot or to perform the same foot action with the goal of guiding an avatar's hand to grasp a small ball. Results showed that pressing a pedal to grasp a ball influenced how participants correctly identified graspable objects as hand-related ones, making their responses more uncertain than before the training. Just pressing a pedal did not have any similar effect. This is evidence that the influence of action on object categorization can be goal-related rather than effector-specific.

  16. Learning the dynamics and time-recursive boundary detection of deformable objects.

    Science.gov (United States)

    Sun, Walter; Cetin, Müjdat; Chan, Raymond; Willsky, Alan S

    2008-11-01

    We propose a principled framework for recursively segmenting deformable objects across a sequence of frames. We demonstrate the usefulness of this method on left ventricular segmentation across a cardiac cycle. The approach involves a technique for learning the system dynamics together with methods of particle-based smoothing as well as nonparametric belief propagation on a loopy graphical model capturing the temporal periodicity of the heart. The dynamic system state is a low-dimensional representation of the boundary, and the boundary estimation involves incorporating curve evolution into recursive state estimation. By formulating the problem as one of state estimation, the segmentation at each particular time is based not only on the data observed at that instant, but also on predictions based on past and future boundary estimates. Although this paper focuses on left ventricle segmentation, the method generalizes to temporally segmenting any deformable object.

  17. Handling multiple objectives in optimization of externalities as objectives for dynamic traffic management.

    NARCIS (Netherlands)

    Wismans, Luc; Berkum, van Eric; Bliemer, Michiel

    2014-01-01

    Dynamic traffic management (DTM) is acknowledged in various policy documents as an important instrument to improve network performance. This network performance is not only a matter of accessibility, since the externalities of traffic are becoming more and more important objectives as well. Optimiza

  18. Deterministic single-file dynamics in collisional representation.

    Science.gov (United States)

    Marchesoni, F; Taloni, A

    2007-12-01

    We re-examine numerically the diffusion of a deterministic, or ballistic single file with preassigned velocity distribution (Jepsen's gas) from a collisional viewpoint. For a two-modal velocity distribution, where half the particles have velocity +/-c, the collisional statistics is analytically proven to reproduce the continuous time representation. For a three-modal velocity distribution with equal fractions, where less than 12 of the particles have velocity +/-c, with the remaining particles at rest, the collisional process is shown to be inhomogeneous; its stationary properties are discussed here by combining exact and phenomenological arguments. Collisional memory effects are then related to the negative power-law tails in the velocity autocorrelation functions, predicted earlier in the continuous time formalism. Numerical and analytical results for Gaussian and four-modal Jepsen's gases are also reported for the sake of a comparison.

  19. Graphics processing units accelerated semiclassical initial value representation molecular dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Tamascelli, Dario; Dambrosio, Francesco Saverio [Dipartimento di Fisica, Università degli Studi di Milano, via Celoria 16, 20133 Milano (Italy); Conte, Riccardo [Department of Chemistry and Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322 (United States); Ceotto, Michele, E-mail: michele.ceotto@unimi.it [Dipartimento di Chimica, Università degli Studi di Milano, via Golgi 19, 20133 Milano (Italy)

    2014-05-07

    This paper presents a Graphics Processing Units (GPUs) implementation of the Semiclassical Initial Value Representation (SC-IVR) propagator for vibrational molecular spectroscopy calculations. The time-averaging formulation of the SC-IVR for power spectrum calculations is employed. Details about the GPU implementation of the semiclassical code are provided. Four molecules with an increasing number of atoms are considered and the GPU-calculated vibrational frequencies perfectly match the benchmark values. The computational time scaling of two GPUs (NVIDIA Tesla C2075 and Kepler K20), respectively, versus two CPUs (Intel Core i5 and Intel Xeon E5-2687W) and the critical issues related to the GPU implementation are discussed. The resulting reduction in computational time and power consumption is significant and semiclassical GPU calculations are shown to be environment friendly.

  20. GPU Accelerated Semiclassical Initial Value Representation Molecular Dynamics

    CERN Document Server

    Tamascelli, Dario; Conte, Riccardo; Ceotto, Michele

    2013-01-01

    This paper presents a graphics processing units (GPUs) implementation of the semiclassical initial value representation (SC-IVR) propagator for vibrational molecular spectroscopy calculations. The time-averaging formulation of the SC-IVR for power spectrum calculations is employed. Details about the CUDA implementation of the semiclassical code are provided. 4 molecules with an increasing number of atoms are considered and the GPU-calculated vibrational frequencies perfectly match the benchmark values. The computational time scaling of two GPUs (C2075 and K20) versus two CPUs (intel core i5 and Intel Xeon E5-2687W) shows that the CPU code scales linearly, whereas the GPU CUDA code roughly constantly for most of the trajectory range considered. Critical issues related to the GPU implementation are discussed. The resulting reduction in computational time and power consumption is significant and semiclassical GPU calculations are shown to be environment friendly.

  1. 面向对象专家系统的知识表示方法研究%Knowledge Representation Method of the Object-oriented Exper System

    Institute of Scientific and Technical Information of China (English)

    温有奎

    2002-01-01

    A method for the construction of an object-oriented expert system with its knowledge database independent of program is introduced. Its knowledge representation,reasoning mechanism, semantic network and frame structure are described in detail. Fimally,the author compares the object-oriented knowledge representation method with the semantic network and frame structure.

  2. Analysing the performance of dynamic multi-objective optimisation algorithms

    CSIR Research Space (South Africa)

    Helbig, M

    2013-06-01

    Full Text Available Congress on Evolutionary Computation, 20-23 June 2013, Cancún, México Analysing the Performance of Dynamic Multi-objective Optimisation Algorithms Marde Helbig CSIR: Meraka Institute, Brummeria, South Africa; and University of Pretoria Computer...

  3. Mapping and tracking of moving objects in dynamic environments

    CSIR Research Space (South Africa)

    Pancham, A

    2012-10-01

    Full Text Available In order for mobile robots to operate in dynamic or real world environments they must be able to localise themselves while building a map of the environment, and detect and track moving objects. This work involves the research and implementation...

  4. Differential representations of dynamical oscillator symmetries in discrete Hilbert space

    Directory of Open Access Journals (Sweden)

    Andreas Ruffing

    2000-01-01

    Full Text Available As a very important example for dynamical symmetries in the context of q-generalized quantum mechanics the algebra aa†−q−2a†a=1 is investigated. It represents the oscillator symmetry SUq(1,1 and is regarded as a commutation phenomenon of the q-Heisenberg algebra which provides a discrete spectrum of momentum and space, i.e., a discrete Hilbert space structure. Generalized q-Hermite functions and systems of creation and annihilation operators are derived. The classical limit q→1 is investigated. Finally the SUq(1,1 algebra is represented by the dynamical variables of the q-Heisenberg algebra.

  5. The bottom-up approach to defining life : deciphering the functional organization of biological cells via multi-objective representation of biological complexity from molecules to cells

    Directory of Open Access Journals (Sweden)

    Sathish ePeriyasamy

    2013-12-01

    Full Text Available In silico representation of cellular systems needs to represent the adaptive dynamics of biological cells, recognizing a cell’s multi-objective topology formed by spatially and temporally cohesive intracellular structures. The design of these models needs to address the hierarchical and concurrent nature of cellular functions and incorporate the ability to self-organise in response to transitions between healthy and pathological phases, and adapt accordingly. The functions of biological systems are constantly evolving, due to the ever changing demands of their environment. Biological systems meet these demands by pursuing objectives, aided by their constituents, giving rise to biological functions. A biological cell is organised into an objective/task hierarchy. These objective hierarchy corresponds to the nested nature of temporally cohesive structures and representing them will facilitate in studying pleiotropy and polygeny by modeling causalities propagating across multiple interconnected intracellular processes. Although biological adaptations occur in physiological, developmental and reproductive timescales, the paper is focused on adaptations that occur within physiological timescales, where the biomolecular activities contributing to functional organisation, play a key role in cellular physiology. The paper proposes a multi-scale and multi-objective modelling approach from the bottom-up by representing temporally cohesive structures for multi-tasking of intracellular processes. Further the paper characterises the properties and constraints that are consequential to the organisational and adaptive dynamics in biological cells.

  6. From Static to Dynamic Mathematics: Historical and Representational Perspectives

    Science.gov (United States)

    Moreno-Armella, Luis; Hegedus, Stephen J.; Kaput, James J.

    2008-01-01

    The nature of mathematical reference fields has substantially evolved with the advent of new types of digital technologies enabling students greater access to understanding the use and application of mathematical ideas and procedures. We analyze the evolution of symbolic thinking over time, from static notations to dynamic inscriptions in new…

  7. Dynamics of Representational Change: Entropy, Action, and Cognition

    Science.gov (United States)

    Stephen, Damian G.; Dixon, James A.; Isenhower, Robert W.

    2009-01-01

    Explaining how the cognitive system can create new structures has been a major challenge for cognitive science. Self-organization from the theory of nonlinear dynamics offers an account of this remarkable phenomenon. Two studies provide an initial test of the hypothesis that the emergence of new cognitive structure follows the same universal…

  8. Continuum neural dynamics models for visual object identification

    Science.gov (United States)

    Singh, Vijay; Tchernookov, Martin; Nemenman, Ilya

    2013-03-01

    Visual object identification has remained one of the most challenging problems even after decades of research. Most of the current models of the visual cortex represent neurons as discrete elements in a largely feedforward network arrangement. They are generally very specific in the objects they can identify. We develop a continuum model of recurrent, nonlinear neural dynamics in the primary visual cortex, incorporating connectivity patterns and other experimentally observed features of the cortex. The model has an interesting correspondence to the Landau-DeGennes theory of a nematic liquid crystal in two dimensions. We use collective spatiotemporal excitations of the model cortex as a signal for segmentation of contiguous objects from the background clutter. The model is capable of suppressing clutter in images and filling in occluded elements of object contours, resulting in high-precision, high-recall identification of large objects from cluttered scenes. This research has been partially supported by the ARO grant No. 60704-NS-II.

  9. Hysteresis in the dynamic perception of scenes and objects.

    Science.gov (United States)

    Poltoratski, Sonia; Tong, Frank

    2014-10-01

    Scenes and objects are effortlessly processed and integrated by the human visual system. Given the distinct neural and behavioral substrates of scene and object processing, it is likely that individuals sometimes preferentially rely on one process or the other when viewing canonical "scene" or "object" stimuli. This would allow the visual system to maximize the specific benefits of these 2 types of processing. It is less obvious which of these modes of perception would be invoked during naturalistic visual transition between a focused view of a single object and an expansive view of an entire scene, particularly at intermediate views that may not be assigned readily to either stimulus category. In the current study, we asked observers to report their online perception of such dynamic image sequences, which zoomed and panned between a canonical view of a single object and an entire scene. We found a large and consistent effect of prior perception, or hysteresis, on the classification of the sequence: observers classified the sequence as an object for several seconds longer if the trial started at the object view and zoomed out, whereas scenes were perceived for longer on trials beginning with a scene view. This hysteresis effect resisted several manipulations of the movie stimulus and of the task performed, but hinged on the perceptual history built by unidirectional progression through the image sequence. Multiple experiments confirmed that this hysteresis effect was not purely decisional and was more prominent for transitions between corresponding objects and scenes than between other high-level stimulus classes. This finding suggests that the competitive mechanisms underlying hysteresis may be especially prominent in the perception of objects and scenes. We propose that hysteresis aids in disambiguating perception during naturalistic visual transitions, which may facilitate a dynamic balance between scene and object processing to enhance processing efficiency.

  10. THE INDUCED REPRESENTATION OF C*-GROUPOID DYNAMIC SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    FANGXIAOCHUN

    1996-01-01

    Let G be a second countable locally compact groupoid with Haar system {λuH}, H be aclosed subgroupoid containing G0 with Haar system {λuH}. T.Masuda introduced the C*-Groupoid dynamic system (G, A, α) and its reduced crossed product Crea(G, A) in [2]: where A is C*-algebra α is the komomorphism G → Aut(A). In this paper the author introduces the C*-groupoid dynamic systems (H,A, α/H) and (H\\G2,A,-α) induced by (G,A,α) and proves that C*red(H, A) and C*red(H\\G2, A) are strongly Morita equivalent Moreover the inducedrepresentation from C*red(H, A) to C*red(G,A) is got.

  11. Optimized shape semantic graph representation for object understanding and recognition in point clouds

    Science.gov (United States)

    Ning, Xiaojuan; Wang, Yinghui; Meng, Weiliang; Zhang, Xiaopeng

    2016-10-01

    To understand and recognize the three-dimensional (3-D) objects represented as point cloud data, we use an optimized shape semantic graph (SSG) to describe 3-D objects. Based on the decomposed components of an object, the boundary surface of different components and the topology of components, the SSG gives a semantic description that is consistent with human vision perception. The similarity measurement of the SSG for different objects is effective for distinguishing the type of object and finding the most similar one. Experiments using a shape database show that the SSG is valuable for capturing the components of the objects and the corresponding relations between them. The SSG is not only suitable for an object without any loops but also appropriate for an object with loops to represent the shape and the topology. Moreover, a two-step progressive similarity measurement strategy is proposed to effectively improve the recognition rate in the shape database containing point-sample data.

  12. The Impact of Density and Ratio on Object-Ensemble Representation in Human Anterior-Medial Ventral Visual Cortex.

    Science.gov (United States)

    Cant, Jonathan S; Xu, Yaoda

    2015-11-01

    Behavioral research has demonstrated that observers can extract summary statistics from ensembles of multiple objects. We recently showed that a region of anterior-medial ventral visual cortex, overlapping largely with the scene-sensitive parahippocampal place area (PPA), participates in object-ensemble representation. Here we investigated the encoding of ensemble density in this brain region using fMRI-adaptation. In Experiment 1, we varied density by changing the spacing between objects and found no sensitivity in PPA to such density changes. Thus, density may not be encoded in PPA, possibly because object spacing is not perceived as an intrinsic ensemble property. In Experiment 2, we varied relative density by changing the ratio of 2 types of objects comprising an ensemble, and observed significant sensitivity in PPA to such ratio change. Although colorful ensembles were shown in Experiment 2, Experiment 3 demonstrated that sensitivity to object ratio change was not driven mainly by a change in the ratio of colors. Thus, while anterior-medial ventral visual cortex is insensitive to density (object spacing) changes, it does code relative density (object ratio) within an ensemble. Object-ensemble processing in this region may thus depend on high-level visual information, such as object ratio, rather than low-level information, such as spacing/spatial frequency.

  13. Complex Phenomena Understanding in Electricity through Dynamically Linked Concrete and Abstract Representations

    Science.gov (United States)

    Taramopoulos, A.; Psillos, D.

    2017-01-01

    The present study investigates the impact of utilizing virtual laboratory environments combining dynamically linked concrete and abstract representations in investigative activities on the ability of students to comprehend simple and complex phenomena in the field of electric circuits. Forty-two 16- to 17-year-old high school students participated…

  14. An Evaluative Review of Simulated Dynamic Smart 3d Objects

    Science.gov (United States)

    Romeijn, H.; Sheth, F.; Pettit, C. J.

    2012-07-01

    Three-dimensional (3D) modelling of plants can be an asset for creating agricultural based visualisation products. The continuum of 3D plants models ranges from static to dynamic objects, also known as smart 3D objects. There is an increasing requirement for smarter simulated 3D objects that are attributed mathematically and/or from biological inputs. A systematic approach to plant simulation offers significant advantages to applications in agricultural research, particularly in simulating plant behaviour and the influences of external environmental factors. This approach of 3D plant object visualisation is primarily evident from the visualisation of plants using photographed billboarded images, to more advanced procedural models that come closer to simulating realistic virtual plants. However, few programs model physical reactions of plants to external factors and even fewer are able to grow plants based on mathematical and/or biological parameters. In this paper, we undertake an evaluation of plant-based object simulation programs currently available, with a focus upon the components and techniques involved in producing these objects. Through an analytical review process we consider the strengths and weaknesses of several program packages, the features and use of these programs and the possible opportunities in deploying these for creating smart 3D plant-based objects to support agricultural research and natural resource management. In creating smart 3D objects the model needs to be informed by both plant physiology and phenology. Expert knowledge will frame the parameters and procedures that will attribute the object and allow the simulation of dynamic virtual plants. Ultimately, biologically smart 3D virtual plants that react to changes within an environment could be an effective medium to visually represent landscapes and communicate land management scenarios and practices to planners and decision-makers.

  15. Object representations in visual working memory change according to the task context.

    Science.gov (United States)

    Balaban, Halely; Luria, Roy

    2016-08-01

    This study investigated whether an item's representation in visual working memory (VWM) can be updated according to changes in the global task context. We used a modified change detection paradigm, in which the items moved before the retention interval. In all of the experiments, we presented identical color-color conjunction items that were arranged to provide a common fate Gestalt grouping cue during their movement. Task context was manipulated by adding a condition highlighting either the integrated interpretation of the conjunction items or their individuated interpretation. We monitored the contralateral delay activity (CDA) as an online marker of VWM. Experiment 1 employed only a minimal global context; the conjunction items were integrated during their movement, but then were partially individuated, at a late stage of the retention interval. The same conjunction items were perfectly integrated in an integration context (Experiment 2). An individuation context successfully produced strong individuation, already during the movement, overriding Gestalt grouping cues (Experiment 3). In Experiment 4, a short priming of the individuation context managed to individuate the conjunction items immediately after the Gestalt cue was no longer available. Thus, the representations of identical items changed according to the task context, suggesting that VWM interprets incoming input according to global factors which can override perceptual cues.

  16. Quantifying the Relationship between Dynamical Cores and Physical Parameterizations by Object-Based Methods

    Science.gov (United States)

    Yorgun, M. S.; Rood, R. B.

    2011-12-01

    The behavior of atmospheric models is sensitive to the algorithms that are used to represent the equations of motion. Typically, comprehensive models are conceived in terms of the resolved fluid dynamics (i.e. the dynamical core) and subgrid, unresolved physics represented by parameterizations. Deterministic weather predictions are often validated with feature-by-feature comparison. Probabilistic weather forecasts and climate projects are evaluated with statistical methods. We seek to develop model evaluation strategies that identify like "objects" - coherent systems with an associated set of measurable parameters. This makes it possible to evaluate processes in models without needing to reproduce the time and location of, for example, a particular observed cloud system. Process- and object-based evaluation preserves information in the observations by avoiding the need for extensive spatial and temporal averaging. As a concrete example, we focus on analyzing how the choice of dynamical core impacts the representation of precipitation in the Pacific Northwest of the United States, Western Canada, and Alaska; this brings attention to the interaction of the resolved and the parameterized components of the model. Two dynamical cores are considered within the Community Atmosphere Model. These are the Spectral (Eulerian), which relies on global basis functions and the Finite Volume (FV), which uses only local information. We introduce the concept of "meteorological realism" that is, do local representations of large-scale phenomena, for example, fronts and orographic precipitation, look like the observations? A follow on question is, does the representation of these phenomena improve with resolution? Our approach to quantify meteorological realism starts with identification and isolation of key features of orographic precipitation that are represented differently by Spectral and FV models, using objective pattern recognition methods. Then we aim to quantitatively compare

  17. Spatiotemporal dynamics of similarity-based neural representations of facial identity.

    Science.gov (United States)

    Vida, Mark D; Nestor, Adrian; Plaut, David C; Behrmann, Marlene

    2017-01-10

    Humans' remarkable ability to quickly and accurately discriminate among thousands of highly similar complex objects demands rapid and precise neural computations. To elucidate the process by which this is achieved, we used magnetoencephalography to measure spatiotemporal patterns of neural activity with high temporal resolution during visual discrimination among a large and carefully controlled set of faces. We also compared these neural data to lower level "image-based" and higher level "identity-based" model-based representations of our stimuli and to behavioral similarity judgments of our stimuli. Between ∼50 and 400 ms after stimulus onset, face-selective sources in right lateral occipital cortex and right fusiform gyrus and sources in a control region (left V1) yielded successful classification of facial identity. In all regions, early responses were more similar to the image-based representation than to the identity-based representation. In the face-selective regions only, responses were more similar to the identity-based representation at several time points after 200 ms. Behavioral responses were more similar to the identity-based representation than to the image-based representation, and their structure was predicted by responses in the face-selective regions. These results provide a temporally precise description of the transformation from low- to high-level representations of facial identity in human face-selective cortex and demonstrate that face-selective cortical regions represent multiple distinct types of information about face identity at different times over the first 500 ms after stimulus onset. These results have important implications for understanding the rapid emergence of fine-grained, high-level representations of object identity, a computation essential to human visual expertise.

  18. Representation of robotic fractional dynamics in the pseudo phase plane

    Institute of Scientific and Technical Information of China (English)

    Miguel F.M. Lima; J.A. Tenreiro Machado

    2011-01-01

    This paper analyses robotic signals in the perspective of fractional dynamics and the pseudo phase plane (PPP). It is shown that the spectra of several experimental signals can be approximated by trend lines whose slope characterizes their fractional behavior. For the PPP reconstruc tion of each signal, the time lags are calculated through the fractal dimension. Moreover, to obtain a smooth PPP, the noisy signals are filtered through wavelets. The behavior of the spectra reveals a relationship with the fractal dimension of the PPP and the corresponding time delay.

  19. Dynamic representation of spectral edges in guinea pig primary auditory cortex.

    Science.gov (United States)

    Montejo, Noelia; Noreña, Arnaud J

    2015-04-01

    The central representation of a given acoustic motif is thought to be strongly context dependent, i.e., to rely on the spectrotemporal past and present of the acoustic mixture in which it is embedded. The present study investigated the cortical representation of spectral edges (i.e., where stimulus energy changes abruptly over frequency) and its dependence on stimulus duration and depth of the spectral contrast in guinea pig. We devised a stimulus ensemble composed of random tone pips with or without an attenuated frequency band (AFB) of variable depth. Additionally, the multitone ensemble with AFB was interleaved with periods of silence or with multitone ensembles without AFB. We have shown that the representation of the frequencies near but outside the AFB is greatly enhanced, whereas the representation of frequencies near and inside the AFB is strongly suppressed. These cortical changes depend on the depth of the AFB: although they are maximal for the largest depth of the AFB, they are also statistically significant for depths as small as 10 dB. Finally, the cortical changes are quick, occurring within a few seconds of stimulus ensemble presentation with AFB, and are very labile, disappearing within a few seconds after the presentation without AFB. Overall, this study demonstrates that the representation of spectral edges is dynamically enhanced in the auditory centers. These central changes may have important functional implications, particularly in noisy environments where they could contribute to preserving the central representation of spectral edges. Copyright © 2015 the American Physiological Society.

  20. Representation of dynamical stimuli in populations of threshold neurons.

    Directory of Open Access Journals (Sweden)

    Tatjana Tchumatchenko

    2011-10-01

    Full Text Available Many sensory or cognitive events are associated with dynamic current modulations in cortical neurons. This raises an urgent demand for tractable model approaches addressing the merits and limits of potential encoding strategies. Yet, current theoretical approaches addressing the response to mean- and variance-encoded stimuli rarely provide complete response functions for both modes of encoding in the presence of correlated noise. Here, we investigate the neuronal population response to dynamical modifications of the mean or variance of the synaptic bombardment using an alternative threshold model framework. In the variance and mean channel, we provide explicit expressions for the linear and non-linear frequency response functions in the presence of correlated noise and use them to derive population rate response to step-like stimuli. For mean-encoded signals, we find that the complete response function depends only on the temporal width of the input correlation function, but not on other functional specifics. Furthermore, we show that both mean- and variance-encoded signals can relay high-frequency inputs, and in both schemes step-like changes can be detected instantaneously. Finally, we obtain the pairwise spike correlation function and the spike triggered average from the linear mean-evoked response function. These results provide a maximally tractable limiting case that complements and extends previous results obtained in the integrate and fire framework.

  1. Dynamic Cell Formation based on Multi-objective Optimization Model

    Directory of Open Access Journals (Sweden)

    Guozhu Jia

    2013-08-01

    Full Text Available In this paper, a multi-objective model is proposed to address the dynamic cellular manufacturing (DCM formation problem. This model considers four conflicting objectives: relocation cost, machine utilization, material handling cost and maintenance cost. The model also considers the situation that some machines could be shared by more than one cell at the same period. A genetic algorithm is applied to get the solution of this mathematical model. Three numerical examples are simulated to evaluate the validity of this model.  

  2. Resilience to the contralateral visual field bias as a window into object representations.

    Science.gov (United States)

    Garcea, Frank E; Kristensen, Stephanie; Almeida, Jorge; Mahon, Bradford Z

    2016-08-01

    Viewing images of manipulable objects elicits differential blood oxygen level-dependent (BOLD) contrast across parietal and dorsal occipital areas of the human brain that support object-directed reaching, grasping, and complex object manipulation. However, it is unknown which object-selective regions of parietal cortex receive their principal inputs from the ventral object-processing pathway and which receive their inputs from the dorsal object-processing pathway. Parietal areas that receive their inputs from the ventral visual pathway, rather than from the dorsal stream, will have inputs that are already filtered through object categorization and identification processes. This predicts that parietal regions that receive inputs from the ventral visual pathway should exhibit object-selective responses that are resilient to contralateral visual field biases. To test this hypothesis, adult participants viewed images of tools and animals that were presented to the left or right visual fields during functional magnetic resonance imaging (fMRI). We found that the left inferior parietal lobule showed robust tool preferences independently of the visual field in which tool stimuli were presented. In contrast, a region in posterior parietal/dorsal occipital cortex in the right hemisphere exhibited an interaction between visual field and category: tool-preferences were strongest contralateral to the stimulus. These findings suggest that action knowledge accessed in the left inferior parietal lobule operates over inputs that are abstracted from the visual input and is contingent on analysis by the ventral visual pathway, consistent with its putative role in supporting object manipulation knowledge.

  3. Come together, right now: dynamic overwriting of an object's history through common fate.

    Science.gov (United States)

    Luria, Roy; Vogel, Edward K

    2014-08-01

    The objects around us constantly move and interact, and the perceptual system needs to monitor on-line these interactions and to update the object's status accordingly. Gestalt grouping principles, such as proximity and common fate, play a fundamental role in how we perceive and group these objects. Here, we investigated situations in which the initial object representation as a separate item was updated by a subsequent Gestalt grouping cue (i.e., proximity or common fate). We used a version of the color change detection paradigm, in which the objects started to move separately, then met and stayed stationary, or moved separately, met, and then continued to move together. We monitored the object representations on-line using the contralateral delay activity (CDA; an ERP component indicative of the number of maintained objects), during their movement, and after the objects disappeared and became working memory representations. The results demonstrated that the objects' representations (as indicated by the CDA amplitude) persisted as being separate, even after a Gestalt proximity cue (when the objects "met" and remained stationary on the same position). Only a strong common fate Gestalt cue (when the objects not just met but also moved together) was able to override the objects' initial separate status, creating an integrated representation. These results challenge the view that Gestalt principles cause reflexive grouping. Instead, the object initial representation plays an important role that can override even powerful grouping cues.

  4. Multi-objective robust airfoil optimization based on non-uniform rational B-spline (NURBS) representation

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In order to improve airfoil performance under different flight conditions and to make the performance insensitive to off-design condition at the same time,a multi-objective optimization approach considering robust design has been developed and applied to airfoil design. Non-uniform rational B-spline (NURBS) representation is adopted in airfoil design process,control points and related weights around airfoil are used as design variables. Two airfoil representation cases show that the NURBS method can get airfoil geometry with max geometry error less than 0.0019. By using six-sigma robust approach in multi-objective airfoil design,each sub-objective function of the problem has robustness property. By adopting multi-objective genetic algorithm that is based on non-dominated sorting,a set of non-dominated airfoil solutions with robustness can be obtained in the design. The optimum robust airfoil can be traded off and selected in these non-dominated solutions by design tendency. By using the above methods,a multi-objective robust optimization was conducted for NASA SC0712 airfoil. After performing robust airfoil optimization,the mean value of drag coefficient at Ma0.7-0.8 and the mean value of lift coefficient at post stall regime (Ma0.3) have been improved by 12.2% and 25.4%. By comparing the aerodynamic force coefficients of optimization result,it shows that: different from single robust airfoil design which just improves the property of drag divergence at Ma0.7-0.8,multi-objective robust design can improve both the drag divergence property at Ma0.7-0.8 and stall property at low speed. The design cases show that the multi-objective robust design method makes the airfoil performance robust under different off-design conditions.

  5. Dynamic Object Identification with SOM-based neural networks

    Directory of Open Access Journals (Sweden)

    Aleksey Averkin

    2014-03-01

    Full Text Available In this article a number of neural networks based on self-organizing maps, that can be successfully used for dynamic object identification, is described. Unique SOM-based modular neural networks with vector quantized associative memory and recurrent self-organizing maps as modules are presented. The structured algorithms of learning and operation of such SOM-based neural networks are described in details, also some experimental results and comparison with some other neural networks are given.

  6. Causation entropy from symbolic representations of dynamical systems

    CERN Document Server

    Cafaro, Carlo; Sun, Jie; Bollt, Erik M

    2015-01-01

    Identification of causal structures and quantification of direct information flows in complex systems is a challenging yet important task, with practical applications in many fields. Data generated by dynamical processes or large-scale systems are often symbolized, either because of the finite resolution of the measurement apparatus, or because of the need of statistical estimation. By algorithmic application of causation entropy, we investigated the effects of symbolization on important concepts such as Markov order and causal structure of the tent map. We uncovered that these quantities depend nonmontonically and, most of all, sensitively on the choice of symbolization. Indeed, we show that Markov order and causal structure do not necessarily converge to their original analog counterparts as the resolution of the partitioning becomes finer.

  7. Dynamics of Scalar Field in Polymer-like Representation

    CERN Document Server

    Han, M; Han, Muxin; Ma, Yongge

    2006-01-01

    In recent twenty years, loop quantum gravity, a background independent approach to unify general relativity and quantum mechanics, has been widely investigated. We consider the quantum dynamics of a real massless scalar field coupled to gravity in this framework. A Hamiltonian operator for the scalar field can be well defined in the coupled diffeomorphism invariant Hilbert space, which is both self-adjoint and positive. On the other hand, the Hamiltonian constraint operator for the scalar field coupled to gravity can be well defined in the coupled kinematical Hilbert space. There are 1-parameter ambiguities due to scalar field in the construction of both operators. The results heighten our confidence that there is no divergence within this background independent and diffeomorphism invariant quantization approach of matter coupled to gravity. Moreover, to avoid possible quantum anomaly, the master constraint programme can be carried out in this coupled system by employing a self-adjoint master constraint opera...

  8. Dynamics of Bose-Einstein Condensates: Exact Representation and Topological Classification of Coherent Matter Waves

    Directory of Open Access Journals (Sweden)

    Leilei Jia

    2014-01-01

    Full Text Available By using the bifurcation theory of dynamical systems, we present the exact representation and topological classification of coherent matter waves in Bose-Einstein condensates (BECs, such as solitary waves and modulate amplitude waves (MAWs. The existence and multiplicity of such waves are determined by the parameter regions selected. The results show that the characteristic of coherent matter waves can be determined by the “angular momentum” in attractive BECs while for repulsive BECs; the waves of the coherent form are all MAWs. All exact explicit parametric representations of the above waves are exhibited and numerical simulations support the result.

  9. The orbit and dynamical evolution of the Chelyabinsk object

    CERN Document Server

    Emel'yanenko, Vacheslav V; Jenniskens, Peter; Popova, Olga P

    2014-01-01

    The orbit of the Chelyabinsk object is calculated, applying the least-squares method directly to astrometric positions. The dynamical evolution of this object in the past is studied by integrating equations of motion for particles with orbits from the confidence region. It is found that the majority of the Chelyabinsk clones reach the near-Sun state. 67 percent of these objects have collisions with the Sun for 15 Myr in our numerical simulations. The distribution of minimum solar distances shows that the most probable time for the encounters of the Chelyabinsk object with the Sun lies in the interval from -0.8 Myr to -2 Myr. This is consistent with the estimate of a cosmic ray exposure age of 1.2 Myr (Popova et al 2013). A parent body of the Chelyabinsk object should experience strong tidal and thermal effects at this time. The possible association of the Chelyabinsk object with 86039 (1999 NC43) and 2008 DJ is discussed.

  10. The Representation of Objects in Apraxia: From Action Execution to Error Awareness

    National Research Council Canada - National Science Library

    Canzano, Loredana; Scandola, Michele; Gobbetto, Valeria; Moretto, Giuseppe; D'Imperio, Daniela; Moro, Valentina

    2016-01-01

    ...., constructive apraxia and magnetic apraxia. Pantomime and the imitation of objects in use are also considered with a view to dissociating the various different components involved in upper limb apraxia...

  11. Representation and Metrics Extraction from Feature Basis: An Object Oriented Approach

    Directory of Open Access Journals (Sweden)

    Fausto Neri da Silva Vanin

    2010-10-01

    Full Text Available This tutorial presents an object oriented approach to data reading and metrics extraction from feature basis. Structural issues about basis are discussed first, then the Object Oriented Programming (OOP is aplied to modeling the main elements in this context. The model implementation is then discussed using C++ as programing language. To validate the proposed model, we apply on some feature basis from the University of Carolina, Irvine Machine Learning Database.

  12. Multi-objective optimization in systematic conservation planning and the representation of genetic variability among populations.

    Science.gov (United States)

    Schlottfeldt, S; Walter, M E M T; Carvalho, A C P L F; Soares, T N; Telles, M P C; Loyola, R D; Diniz-Filho, J A F

    2015-06-18

    Biodiversity crises have led scientists to develop strategies for achieving conservation goals. The underlying principle of these strategies lies in systematic conservation planning (SCP), in which there are at least 2 conflicting objectives, making it a good candidate for multi-objective optimization. Although SCP is typically applied at the species level (or hierarchically higher), it can be used at lower hierarchical levels, such as using alleles as basic units for analysis, for conservation genetics. Here, we propose a method of SCP using a multi-objective approach. We used non-dominated sorting genetic algorithm II in order to identify the smallest set of local populations of Dipteryx alata (baru) (a Brazilian Cerrado species) for conservation, representing the known genetic diversity and using allele frequency information associated with heterozygosity and Hardy-Weinberg equilibrium. We worked in 3 variations for the problem. First, we reproduced a previous experiment, but using a multi-objective approach. We found that the smallest set of populations needed to represent all alleles under study was 7, corroborating the results of the previous study, but with more distinct solutions. In the 2nd and 3rd variations, we performed simultaneous optimization of 4 and 5 objectives, respectively. We found similar but refined results for 7 populations, and a larger portfolio considering intra-specific diversity and persistence with populations ranging from 8-22. This is the first study to apply multi-objective algorithms to an SCP problem using alleles at the population level as basic units for analysis.

  13. Empowered objects, powerless subjects: citizenship, religion, and political representation in twentieth-century Cuba

    Directory of Open Access Journals (Sweden)

    Olivia Maria Gomes da Cunha

    2008-12-01

    Full Text Available [First paragraph] Measures of Equality: Social Science, Citizenship, and Race in Cuba, 1902-1940. Alejandra Marina Bronfman. Chapel Hill: University of North Carolina Press, 2004. xi + 234 pp. (Paper US$ 19.95 Afro-Cuban Religiosity, Revolution, and National Identity. Christine Ayorinde. Gainesville: University Press of Florida, 2004. ix + 283 pp. (Cloth US$ 59.95 In the last ten years, research topics such as race and nation have been privileged areas for the historical and anthropological understanding of Caribbean and Latin American societies. Regarding Cuba in particular, social scientists have dedicated important scholarship to these issues by mapping conceptions of citizenship and political representation, while situating them within a broader debate on the making of the new postcolonial and republican society at the beginning of the twentieth century. By pursuing different aims and following distinct approaches, Alejandra Bronfman and Christine Ayorinde have made contributions to this academic literature. Through divergent theoretical and methodological perspectives, both of their books explore alternative ways of interpreting the making of the nation founded upon a multiple and fluid rhetoric of race.

  14. Dilated contour extraction and component labeling algorithm for object vector representation

    Science.gov (United States)

    Skourikhine, Alexei N.

    2005-08-01

    Object boundary extraction from binary images is important for many applications, e.g., image vectorization, automatic interpretation of images containing segmentation results, printed and handwritten documents and drawings, maps, and AutoCAD drawings. Efficient and reliable contour extraction is also important for pattern recognition due to its impact on shape-based object characterization and recognition. The presented contour tracing and component labeling algorithm produces dilated (sub-pixel) contours associated with corresponding regions. The algorithm has the following features: (1) it always produces non-intersecting, non-degenerate contours, including the case of one-pixel wide objects; (2) it associates the outer and inner (i.e., around hole) contours with the corresponding regions during the process of contour tracing in a single pass over the image; (3) it maintains desired connectivity of object regions as specified by 8-neighbor or 4-neighbor connectivity of adjacent pixels; (4) it avoids degenerate regions in both background and foreground; (5) it allows an easy augmentation that will provide information about the containment relations among regions; (6) it has a time complexity that is dominantly linear in the number of contour points. This early component labeling (contour-region association) enables subsequent efficient object-based processing of the image information.

  15. The dynamic representation of gravity is suspended when the idiotropic vector is misaligned with gravity.

    Science.gov (United States)

    De Sá Teixeira, Nuno Alexandre; Hecht, Heiko

    2014-01-01

    When people are asked to indicate the vanishing location of a moving target, errors in the direction of motion (representational momentum) and in the direction of gravity (representational gravity) are usually found. These errors possess a temporal course wherein the memory for the location of the target drifts downwards with increasing temporal intervals between target's disappearance and participant's responses (representational trajectory). To assess if representational trajectory is a body-referenced or a world-referenced phenomenon. A behavioral localization method was employed with retention times between 0 and 1400 ms systematically imposed after the target's disappearance. The target could move horizontally (rightwards or leftwards) or vertically (upwards or downwards). Body posture was varied in a counterbalanced order between sitting upright and lying on the side (left lateral decubitus position). In the upright task, the memory for target location drifted downwards with time in the direction of gravity. This time course did not emerge for the decubitus task, where idiotropic dominance was found. The dynamic visual representation of gravity is neither purely body-referenced nor world-referenced. It seems to be modulated instead by the relationship between the idiotropic vector and physical gravity.

  16. [The epistemic objects of toxoplasmoses and their re-presentation in an international scientific conference].

    Science.gov (United States)

    Silva, Vera Lucia Marques da; Camargo Júnior, Kenneth Rochel de

    2012-06-01

    The paper investigates the epistemic objects of Toxoplasma gondii and the correlation of forces of research groups committed to redefine or reconfigure toxoplasmosis. The data research and this analysis were conducted in a scientific congress, according to the concepts of 'manipulation' and 'reenactment,' based on the idea of 'dramatization' proposed by Mol in a study of empirical philosophy. It was found that the objects were represented from diversified hues and with strong ties to the industrial complex. For its projection in the trends of the global economy in the twenty-first century, genetics was a major protagonist in the debates on sole causality, one of the convictions of Western science.

  17. Dynamic Uncertain Causality Graph for Knowledge Representation and Reasoning: Discrete DAG Cases

    Institute of Scientific and Technical Information of China (English)

    Qin Zhang

    2012-01-01

    Developed from the dynamic causality diagram (DCD) model,a new approach for knowledge representation and reasoning named as dynamic uncertain causality graph (DUCG) is presented,which focuses on the compact representation of complex uncertain causalities and efficient probabilistic inference.It is pointed out that the existing models of compact representation and inference in Bayesian Network (BN) is applicable in single-valued cases,but may not be suitable to be applied in multi-valued cases.DUCG overcomes this problem and beyond.The main features of DUCG are:1) compactly and graphically representing complex conditional probability distributions (CPDs),regardless of whether the cases are single-valued or multi-valued; 2) able to perform exact reasoning in the case of the incomplete knowledge representation;3) simplifying the graphical knowledge base conditional on observations before other calculations,so that the scale and complexity of problem can be reduced exponentially; 4) the efficient two-step inference algorithm consisting of (a) logic operation to find all possible hypotheses in concern for given observations and (b) the probability calculation for these hypotheses; and 5) much less relying on the parameter accuracy.An alarm system example is provided to illustrate the DUCG methodology.

  18. Locality constrained joint dynamic sparse representation for local matching based face recognition.

    Directory of Open Access Journals (Sweden)

    Jianzhong Wang

    Full Text Available Recently, Sparse Representation-based Classification (SRC has attracted a lot of attention for its applications to various tasks, especially in biometric techniques such as face recognition. However, factors such as lighting, expression, pose and disguise variations in face images will decrease the performances of SRC and most other face recognition techniques. In order to overcome these limitations, we propose a robust face recognition method named Locality Constrained Joint Dynamic Sparse Representation-based Classification (LCJDSRC in this paper. In our method, a face image is first partitioned into several smaller sub-images. Then, these sub-images are sparsely represented using the proposed locality constrained joint dynamic sparse representation algorithm. Finally, the representation results for all sub-images are aggregated to obtain the final recognition result. Compared with other algorithms which process each sub-image of a face image independently, the proposed algorithm regards the local matching-based face recognition as a multi-task learning problem. Thus, the latent relationships among the sub-images from the same face image are taken into account. Meanwhile, the locality information of the data is also considered in our algorithm. We evaluate our algorithm by comparing it with other state-of-the-art approaches. Extensive experiments on four benchmark face databases (ORL, Extended YaleB, AR and LFW demonstrate the effectiveness of LCJDSRC.

  19. Dentate Gyrus Is Necessary for Disambiguating Similar Object-Place Representations

    Science.gov (United States)

    Lee, Inah; Solivan, Frances

    2010-01-01

    Objects are often remembered with their locations, which is an important aspect of event memory. Despite the well-known involvement of the hippocampus in event memory, detailed intrahippocampal mechanisms are poorly understood. In particular, no experimental evidence has been provided in support of the role of the dentate gyrus (DG) in…

  20. Analytical representations of precise orbit predictions for Earth orbiting space objects

    Science.gov (United States)

    Sang, Jizhang; Li, Bin; Chen, Junyu; Zhang, Pin; Ning, Jinsheng

    2017-01-01

    Accurate orbits of Earth orbiting space objects are usually generated from an orbit determination/prediction process using numerical integrators, and presented to users in a tabulated form or a state vector including force model parameters. When dealing with hundreds of thousands of space objects such as in the space conjunction assessment, the memory required for the tabulated orbits or the computing time for propagating orbits using the state vector are both confronting to users. This paper presents two methods of analytically representing numerical orbits considering the accuracy, computing efficiency and memory. The first one is a two-step TLE-based method in which the numerical orbits are first fitted into a TLE set and then correction functions are applied to improve the position accuracy. In the second method, the orbit states are represented in equinoctial elements first, and then again correction functions are applied to reduce the position errors. Experiments using six satellite laser ranging (SLR) satellites and 12 debris objects with accurate orbits show that both methods can represent the accurate orbits over 5 days in an accuracy of a few dozens of meters for the circular orbits and several hundred meters for the eccentric orbits. The computing time is similar to that using the NORAD TLE/SGP4 algorithm, and storage for the orbit elements and function coefficients is about 3-5 KB. These features could make the two methods beneficial for the maintenance of orbit catalog of large numbers of space objects.

  1. Dentate Gyrus Is Necessary for Disambiguating Similar Object-Place Representations

    Science.gov (United States)

    Lee, Inah; Solivan, Frances

    2010-01-01

    Objects are often remembered with their locations, which is an important aspect of event memory. Despite the well-known involvement of the hippocampus in event memory, detailed intrahippocampal mechanisms are poorly understood. In particular, no experimental evidence has been provided in support of the role of the dentate gyrus (DG) in…

  2. An Object-Oriented Approach to Knowledge Representation in a Biomedical Domain

    NARCIS (Netherlands)

    Ensing, M.; Paton, R.; Speel, P.H.W.M.; Speel, P.H.W.M.; Rada, R.

    1994-01-01

    An object-oriented approach has been applied to the different stages involved in developing a knowledge base about insulin metabolism. At an early stage the separation of terminological and assertional knowledge was made. The terminological component was developed by medical experts and represented

  3. [The influence of camera-to-object distance and focal length on the representation of faces].

    Science.gov (United States)

    Verhoff, Marcel A; Witzel, Carsten; Ramsthaler, Frank; Kreutz, Kerstin

    2007-01-01

    When one thinks of the so-called barrel or wide-angle distortion, grotesquely warped faces may come to mind. For less extreme cases with primarily inconspicuous facial proportions, the question, however, still arises whether there may be a resulting impact on the identification of faces. In the first experiment, 3 test persons were photographed at a fixed camera-to-object distance of 2 m. In the second experiment, 18 test persons were each photographed at a distance of 0.5 m and 2.0 m. For both experiments photographs were taken from a fixed angle of view in alignment with the Frankfurt Plane. An isolated effect of the focal length on facial proportions could not be demonstrated. On the other hand, changes in the camera-to-object distance clearly influenced facial proportions and shape. A standardized camera-to-object distance for passport photos, as well as reconstruction of the camera-to-object distance from crime scene photos and the use of this same distance in taking photographs for comparison of suspects are called for. A proposal to refer to wide-angle distortion as the nearness effect is put forward.

  4. Grammatical Gender and Mental Representation of Object: The Case of Musical Instruments

    Science.gov (United States)

    Vuksanovic, Jasmina; Bjekic, Jovana; Radivojevic, Natalija

    2015-01-01

    A body of research shows that grammatical gender, although an arbitrary category, is viewed as the system with its own meaning. However, the question remains to what extent does grammatical gender influence shaping our notions about objects when both verbal and visual information are available. Two experiments were conducted. The results obtained…

  5. Prior knowledge about objects determines neural color representation in human visual cortex

    NARCIS (Netherlands)

    Vandenbroucke, A.R.E.; Fahrenfort, J.J.; Meuwese, J.D.I.; Scholte, H.S.; Lamme, V.A.F.

    2016-01-01

    To create subjective experience, our brain must translate physical stimulus input by incorporating prior knowledge and expectations. For example, we perceive color and not wavelength information, and this in part depends on our past experience with colored objects ( Hansen et al. 2006; Mitterer and

  6. A continuous semantic space describes the representation of thousands of object and action categories across the human brain.

    Science.gov (United States)

    Huth, Alexander G; Nishimoto, Shinji; Vu, An T; Gallant, Jack L

    2012-12-20

    Humans can see and name thousands of distinct object and action categories, so it is unlikely that each category is represented in a distinct brain area. A more efficient scheme would be to represent categories as locations in a continuous semantic space mapped smoothly across the cortical surface. To search for such a space, we used fMRI to measure human brain activity evoked by natural movies. We then used voxelwise models to examine the cortical representation of 1,705 object and action categories. The first few dimensions of the underlying semantic space were recovered from the fit models by principal components analysis. Projection of the recovered semantic space onto cortical flat maps shows that semantic selectivity is organized into smooth gradients that cover much of visual and nonvisual cortex. Furthermore, both the recovered semantic space and the cortical organization of the space are shared across different individuals.

  7. Light-front representation of chiral dynamics in peripheral transverse densities

    CERN Document Server

    Granados, C

    2015-01-01

    The nucleon's electromagnetic form factors are expressed in terms of the transverse densities of charge and magnetization at fixed light-front time. At peripheral transverse distances $b = O(M_\\pi^{-1})$ the densities are governed by chiral dynamics and can be calculated model-independently using chiral effective field theory (EFT). We represent the leading-order chiral EFT results for the peripheral transverse densities as overlap integrals of chiral light-front wave functions, describing the transition of the initial nucleon to soft pion-nucleon intermediate states and back. The new representation (a) explains the parametric order of the peripheral transverse densities; (b) establishes an inequality between the spin-independent and -dependent densities; (c) exposes the role of pion orbital angular momentum in chiral dynamics; (d) reveals a large left-right asymmetry of the current in a transversely polarized nucleon and suggests a simple interpretation. The light-front representation enables a first-quantiz...

  8. Object shape classification and scene shape representation for three-dimensional laser scanned outdoor data

    Science.gov (United States)

    Ning, Xiaojuan; Wang, Yinghui; Zhang, Xiaopeng

    2013-02-01

    Shape analysis of a three-dimensional (3-D) scene is an important issue and could be widely used for various applications: city planning, robot navigation, virtual tourism, etc. We introduce an approach for understanding the primitive shape of the scene to reveal the semantic scene shape structure and represent the scene using shape elements. The scene objects are labeled and recognized using the geometric and semantic features for each cluster, which is based on the knowledge of scene. Furthermore, the object in scene with a different primitive shape could also be classified and fitted using the Gaussian map of the segmented scene. We demonstrate the presented approach on several complex scenes from laser scanning. According to the experimental result, the proposed method can accurately represent the geometric structure of the 3-D scene.

  9. THE REPRESENTATION OF OBJECTS IN APRAXIA: FROM ACTION EXECUTION TO ERROR AWARENESS

    OpenAIRE

    LOREDANA eCANZANO; MICHELE eSCANDOLA; VALERIA eGOBBETTO; GIUSEPPE eMORETTO; DANIELA eD'IMPERIO; VALENTINA eMORO

    2016-01-01

    Apraxia is a well-known syndrome characterized by the sufferer’s inability to perform routine gestures. In an attempt to understand the syndrome better, various different theories have been developed and a number of classifications of different subtypes have been proposed. In this paper review, we will address these theories with a specific focus on how the use of objects helps us to better understand upper limb apraxia. With this aim, we will consider transitive versus intransitive action di...

  10. The Representation of Objects in Apraxia: From Action Execution to Error Awareness

    OpenAIRE

    Canzano, Loredana; Scandola, Michele; Gobbetto, Valeria; Moretto, Giuseppe; D’Imperio, Daniela; Moro, Valentina

    2016-01-01

    Apraxia is a well-known syndrome characterized by the sufferer’s inability to perform routine gestures. In an attempt to understand the syndrome better, various different theories have been developed and a number of classifications of different subtypes have been proposed. In this article review, we will address these theories with a specific focus on how the use of objects helps us to better understand upper limb apraxia. With this aim, we will consider transitive vs. intransitive action dis...

  11. Impairments in part-whole representations of objects in two cases of integrative visual agnosia.

    Science.gov (United States)

    Behrmann, Marlene; Williams, Pepper

    2007-10-01

    How complex multipart visual objects are represented perceptually remains a subject of ongoing investigation. One source of evidence that has been used to shed light on this issue comes from the study of individuals who fail to integrate disparate parts of visual objects. This study reports a series of experiments that examine the ability of two such patients with this form of agnosia (integrative agnosia; IA), S.M. and C.R., to discriminate and categorize exemplars of a rich set of novel objects, "Fribbles", whose visual similarity (number of shared parts) and category membership (shared overall shape) can be manipulated. Both patients performed increasingly poorly as the number of parts required for differentiating one Fribble from another increased. Both patients were also impaired at determining when two Fribbles belonged in the same category, a process that relies on abstracting spatial relations between parts. C.R., the less impaired of the two, but not S.M., eventually learned to categorize the Fribbles but required substantially more training than normal perceivers. S.M.'s failure is not attributable to a problem in learning to use a label for identification nor is it obviously attributable to a visual memory deficit. Rather, the findings indicate that, although the patients may be able to represent a small number of parts independently, in order to represent multipart images, the parts need to be integrated or chunked into a coherent whole. It is this integrative process that is impaired in IA and appears to play a critical role in the normal object recognition of complex images.

  12. Formal Transformations from Graphically-Based Object-Oriented Representations to Theory-Based Specifications

    Science.gov (United States)

    1996-06-01

    for Software Synthesis." KBSE 󈨡. IEEE, 1993. 51. Kang, Kyo C., et al. Feature-Oriented Domain Analysis ( FODA ) Feasibility Study. Technical Report...and usefulness in domain analysis and modeling. Rumbaugh uses three distinct views to describe a domain: (1) the object model describes structural...Gibbons describe a methodology where Structured Analysis is used to build a hierarchical system structure chart. This structure chart is then translated

  13. Identification of GCM Uncertainty of Dynamical Cores and Physical Parameterizations by Object-Based Methods

    Science.gov (United States)

    Yorgun, M. S.; Rood, R. B.

    2012-12-01

    The behavior of atmospheric models is sensitive to the algorithms that are used to represent the equations of motion. Typically, comprehensive models are conceived in terms of the resolved fluid dynamics (i.e. the dynamical core) and subgrid, unresolved physics represented by parameterizations. There are model uncertainties inherent to both components. In this study, we investigate the role of the dynamical core as the source of uncertainty in simulation of orographic precipitation by different models. As a concrete example, we focus on analyzing how the choice of dynamical core impacts the representation of precipitation in the Pacific Northwest of the United States, Western Canada, and Alaska; this brings attention to the interaction of the resolved and the parameterized components of the model. Two dynamical cores are considered within the Community Atmosphere Model. These are the Spectral (Eulerian), which relies on global basis functions and the Finite Volume (FV), which uses only local information. We aim to identify and quantify the relationship between the model uncertainty and the numerical scheme as well as other model parameters such as the treatment of topography, SST etc. We also focus on the evolution of the uncertainty as a function of model resolution. In order to evaluate model uncertainty through validation against observations we introduce the concept of "meteorological realism" that is, do local representations of large-scale phenomena, for example, fronts and orographic precipitation, look like the observations? Our approach to quantify meteorological realism employs objective pattern recognition methods using semantic lists for isolated features to define their characteristics. We seek to develop model evaluation strategies that identify like "objects" - coherent systems with an associated set of measurable parameters. This makes it possible to evaluate processes and assess the sources of uncertainty in models without needing to reproduce the

  14. Dynamic Model and Control of a Photovoltaic Generation System using Energetic Macroscopic Representation

    Science.gov (United States)

    Solano, Javier; Duarte, José; Vargas, Erwin; Cabrera, Jhon; Jácome, Andrés; Botero, Mónica; Rey, Juan

    2016-10-01

    This paper addresses the Energetic Macroscopic Representation EMR, the modelling and the control of photovoltaic panel PVP generation systems for simulation purposes. The model of the PVP considers the variations on irradiance and temperature. A maximum power point tracking MPPT algorithm is considered to control the power converter. A novel EMR is proposed to consider the dynamic model of the PVP with variations in the irradiance and the temperature. The EMR is evaluated through simulations of a PVP generation system.

  15. An archived multi-objective simulated annealing for a dynamic cellular manufacturing system

    Science.gov (United States)

    Shirazi, Hossein; Kia, Reza; Javadian, Nikbakhsh; Tavakkoli-Moghaddam, Reza

    2014-05-01

    To design a group layout of a cellular manufacturing system (CMS) in a dynamic environment, a multi-objective mixed-integer non-linear programming model is developed. The model integrates cell formation, group layout and production planning (PP) as three interrelated decisions involved in the design of a CMS. This paper provides an extensive coverage of important manufacturing features used in the design of CMSs and enhances the flexibility of an existing model in handling the fluctuations of part demands more economically by adding machine depot and PP decisions. Two conflicting objectives to be minimized are the total costs and the imbalance of workload among cells. As the considered objectives in this model are in conflict with each other, an archived multi-objective simulated annealing (AMOSA) algorithm is designed to find Pareto-optimal solutions. Matrix-based solution representation, a heuristic procedure generating an initial and feasible solution and efficient mutation operators are the advantages of the designed AMOSA. To demonstrate the efficiency of the proposed algorithm, the performance of AMOSA is compared with an exact algorithm (i.e., ∈-constraint method) solved by the GAMS software and a well-known evolutionary algorithm, namely NSGA-II for some randomly generated problems based on some comparison metrics. The obtained results show that the designed AMOSA can obtain satisfactory solutions for the multi-objective model.

  16. On the adiabatic representation of Meyer-Miller electronic-nuclear dynamics.

    Science.gov (United States)

    Cotton, Stephen J; Liang, Ruibin; Miller, William H

    2017-08-14

    The Meyer-Miller (MM) classical vibronic (electronic + nuclear) Hamiltonian for electronically non-adiabatic dynamics-as used, for example, with the recently developed symmetrical quasiclassical (SQC) windowing model-can be written in either a diabatic or an adiabatic representation of the electronic degrees of freedom, the two being a canonical transformation of each other, thus giving the same dynamics. Although most recent applications of this SQC/MM approach have been carried out in the diabatic representation-because most of the benchmark model problems that have exact quantum results available for comparison are typically defined in a diabatic representation-it will typically be much more convenient to work in the adiabatic representation, e.g., when using Born-Oppenheimer potential energy surfaces (PESs) and derivative couplings that come from electronic structure calculations. The canonical equations of motion (EOMs) (i.e., Hamilton's equations) that come from the adiabatic MM Hamiltonian, however, in addition to the common first-derivative couplings, also involve second-derivative non-adiabatic coupling terms (as does the quantum Schrödinger equation), and the latter are considerably more difficult to calculate. This paper thus revisits the adiabatic version of the MM Hamiltonian and describes a modification of the classical adiabatic EOMs that are entirely equivalent to Hamilton's equations but that do not involve the second-derivative couplings. The second-derivative coupling terms have not been neglected; they simply do not appear in these modified adiabatic EOMs. This means that SQC/MM calculations can be carried out in the adiabatic representation, without approximation, needing only the PESs and the first-derivative coupling elements. The results of example SQC/MM calculations are presented, which illustrate this point, and also the fact that simply neglecting the second-derivative couplings in Hamilton's equations (and presumably also in the Schr

  17. Multi-objective control of nonlinear boiler-turbine dynamics with actuator magnitude and rate constraints.

    Science.gov (United States)

    Chen, Pang-Chia

    2013-01-01

    This paper investigates multi-objective controller design approaches for nonlinear boiler-turbine dynamics subject to actuator magnitude and rate constraints. System nonlinearity is handled by a suitable linear parameter varying system representation with drum pressure as the system varying parameter. Variation of the drum pressure is represented by suitable norm-bounded uncertainty and affine dependence on system matrices. Based on linear matrix inequality algorithms, the magnitude and rate constraints on the actuator and the deviations of fluid density and water level are formulated while the tracking abilities on the drum pressure and power output are optimized. Variation ranges of drum pressure and magnitude tracking commands are used as controller design parameters, determined according to the boiler-turbine's operation range.

  18. Ego, drives, and the dynamics of internal objects

    Directory of Open Access Journals (Sweden)

    Simon eBoag

    2014-07-01

    Full Text Available This paper addresses the relationship between the ego, id, and internal objects. While ego psychology views the ego as autonomous of the drives, a less well-known alternative position views the ego as constituted by the drives. Based on Freud’s ego-instinct account, this position has developed into a school of thought which postulates that the drives act as knowers. Given that there are multiple drives, this position proposes that personality is constituted by multiple knowers. Following on from Freud, the ego is viewed as a composite sub-set of the instinctual drives (ego-drives, whereas those drives cut off from expression form the id. The nature of the ‘self’ is developed in terms of identification and the possibility of multiple personalities is also established. This account is then extended to object-relations and the explanatory value of the ego-drive account is discussed in terms of the addressing the nature of ego-structures and the dynamic nature of internal objects. Finally, the impact of psychological conflict and the significance of repression for understanding the nature of splits within the psyche are also discussed.

  19. Ventral-stream-like shape representation: from pixel intensity values to trainable object-selective COSFIRE models

    Directory of Open Access Journals (Sweden)

    George eAzzopardi

    2014-07-01

    Full Text Available The remarkable abilities of the primate visual cortex have inspired the construction of computational models of some visual neurons. We propose a trainable hierarchical object recognition model, which we call S-COSFIRE (S stands for Shape and COSFIRE stands for Combination Of Shifted FIlter REsponses and use it to localize and recognize objects of interests embedded in complex scenes. It is inspired by the visual processing in the ventral stream (V1/V2 -> V4 -> TEO. Recognition and localization of objects embedded in complex scenes is important for many computer vision applications. Most existing methods require prior segmentation of the objects from the background which on its turn requires recognition. A S-COSFIRE filter is automatically configured to be selective for an arrangement of contour-based features that belong to a prototype shape specified by an example. The configuration comprises selecting relevant vertex detectors and determining certain blur and shift parameters. The response is computed as the weighted geometric mean of the blurred and shifted responses of the selected vertex detectors. S-COSFIRE filters share similar properties with some neurons in inferotemporal cortex, which provided inspiration for this work. We demonstrate the effectiveness of S-COSFIRE filters in two applications: letter and keyword spotting in handwritten manuscripts and object spotting in complex scenes for the computer vision system of a domestic robot. S-COSFIRE filters are effective to recognize and localize (deformable objects in images of complex scenes without requiring prior segmentation. They are versatile trainable shape detectors, conceptually simple and easy to implement. The presented hierarchical shape representation contributes to a better understanding of the brain and to more robust computer vision algorithms.

  20. Detection of dual-band infrared small target based on joint dynamic sparse representation

    Science.gov (United States)

    Zhou, Jinwei; Li, Jicheng; Shi, Zhiguang; Lu, Xiaowei; Ren, Dongwei

    2015-10-01

    Infrared small target detection is a crucial and yet still is a difficult issue in aeronautic and astronautic applications. Sparse representation is an important mathematic tool and has been used extensively in image processing in recent years. Joint sparse representation is applied in dual-band infrared dim target detection in this paper. Firstly, according to the characters of dim targets in dual-band infrared images, 2-dimension Gaussian intensity model was used to construct target dictionary, then the dictionary was classified into different sub-classes according to different positions of Gaussian function's center point in image block; The fact that dual-band small targets detection can use the same dictionary and the sparsity doesn't lie in atom-level but in sub-class level was utilized, hence the detection of targets in dual-band infrared images was converted to be a joint dynamic sparse representation problem. And the dynamic active sets were used to describe the sparse constraint of coefficients. Two modified sparsity concentration index (SCI) criteria was proposed to evaluate whether targets exist in the images. In experiments, it shows that the proposed algorithm can achieve better detecting performance and dual-band detection is much more robust to noise compared with single-band detection. Moreover, the proposed method can be expanded to multi-spectrum small target detection.

  1. Comparative kinetics of the snowball respect to other dynamical objects

    CERN Document Server

    Díaz, R A; Marin, F; Martínez, R; Diaz, Rodolfo A.; Gonzalez, Diego L.; Marin, Francisco

    2003-01-01

    We examine the kinetics of a snowball that is gaining mass while is rolling downhill. This dynamical system combines rotational effects with effects involving the variation of mass. In order to understand the consequences of both effects we compare its behavior with the one of some objects in which such effects are absent. Environmental conditions are also included. We conclude that the comparative velocity of the snowball is very sensitive to the hill profile and the retardation factors. We emphasize that the increase of mass (inertia), could surprisingly diminish the retardation effect due to the drag force. Additionally, when an exponential trajectory is assumed, the maximum velocity of the snowball can be reached at an intermediate step of the trip.

  2. Aspect-Aided Dynamic Non-Negative Sparse Representation-Based Microwave Image Classification

    Directory of Open Access Journals (Sweden)

    Xinzheng Zhang

    2016-09-01

    Full Text Available Classification of target microwave images is an important application in much areas such as security, surveillance, etc. With respect to the task of microwave image classification, a recognition algorithm based on aspect-aided dynamic non-negative least square (ADNNLS sparse representation is proposed. Firstly, an aspect sector is determined, the center of which is the estimated aspect angle of the testing sample. The training samples in the aspect sector are divided into active atoms and inactive atoms by smooth self-representative learning. Secondly, for each testing sample, the corresponding active atoms are selected dynamically, thereby establishing dynamic dictionary. Thirdly, the testing sample is represented with ℓ 1 -regularized non-negative sparse representation under the corresponding dynamic dictionary. Finally, the class label of the testing sample is identified by use of the minimum reconstruction error. Verification of the proposed algorithm was conducted using the Moving and Stationary Target Acquisition and Recognition (MSTAR database which was acquired by synthetic aperture radar. Experiment results validated that the proposed approach was able to capture the local aspect characteristics of microwave images effectively, thereby improving the classification performance.

  3. Dynamical implantation of objects in the Kuiper Belt

    Energy Technology Data Exchange (ETDEWEB)

    Brasil, P. I. O. [Instituto Nacional de Pesquisas Espaciais (INPE), ETE/DMC, Av. dos Astronautas, 1758, São José dos Campos (Brazil); Nesvorný, D.; Gomes, R. S., E-mail: pedro_brasil87@hotmail.com, E-mail: davidn@boulder.swri.edu, E-mail: rodney@on.br [Department of Space Studies, Southwest Research Institute, 1050 Walnut Street, Boulder, CO (United States)

    2014-09-01

    Several models have been suggested in the past to describe the dynamical formation of hot Kuiper Belt objects (hereafter Hot Classicals or HCs for short). Here, we discuss a dynamical mechanism that allows orbits to evolve from the primordial planetesimal disk at ≲ 35 AU to reach the orbital region now occupied by HCs. We performed three different sets of numerical simulations to illustrate this mechanism. Two of these simulations were based on modern theories for the early evolution of the solar system (the Nice and jumping-Jupiter models). The third simulation was performed with the purpose of increasing the resolution at 41-46 AU. The common aspect of these simulations is that Neptune scatters planetesimals from ≲ 35 AU to >40 AU and then undergoes a long phase of slow residual migration. Our results show that to reach an HC orbit, a scattered planetesimal needs to be captured in a mean motion resonance (MMR) with Neptune where the perihelion distance rises due to the Kozai resonance (which occurs in MMRs even for moderate inclinations). Finally, while Neptune is still migrating, the planetesimal is released from the MMR on a stable HC orbit. We show that the orbital distribution of HCs expected from this process provides a reasonable match to observations. The capture efficiency and the mass deposited into the HC region appears to be sensitive to the maximum eccentricity reached by Neptune during the planetary instability phase. Additional work will be needed to resolve this dependency in detail.

  4. Reconstructing dynamic mental models of facial expressions in prosopagnosia reveals distinct representations for identity and expression.

    Science.gov (United States)

    Richoz, Anne-Raphaëlle; Jack, Rachael E; Garrod, Oliver G B; Schyns, Philippe G; Caldara, Roberto

    2015-04-01

    The human face transmits a wealth of signals that readily provide crucial information for social interactions, such as facial identity and emotional expression. Yet, a fundamental question remains unresolved: does the face information for identity and emotional expression categorization tap into common or distinct representational systems? To address this question we tested PS, a pure case of acquired prosopagnosia with bilateral occipitotemporal lesions anatomically sparing the regions that are assumed to contribute to facial expression (de)coding (i.e., the amygdala, the insula and the posterior superior temporal sulcus--pSTS). We previously demonstrated that PS does not use information from the eye region to identify faces, but relies on the suboptimal mouth region. PS's abnormal information use for identity, coupled with her neural dissociation, provides a unique opportunity to probe the existence of a dichotomy in the face representational system. To reconstruct the mental models of the six basic facial expressions of emotion in PS and age-matched healthy observers, we used a novel reverse correlation technique tracking information use on dynamic faces. PS was comparable to controls, using all facial features to (de)code facial expressions with the exception of fear. PS's normal (de)coding of dynamic facial expressions suggests that the face system relies either on distinct representational systems for identity and expression, or dissociable cortical pathways to access them. Interestingly, PS showed a selective impairment for categorizing many static facial expressions, which could be accounted for by her lesion in the right inferior occipital gyrus. PS's advantage for dynamic facial expressions might instead relate to a functionally distinct and sufficient cortical pathway directly connecting the early visual cortex to the spared pSTS. Altogether, our data provide critical insights on the healthy and impaired face systems, question evidence of deficits

  5. Nonlinear dynamic analysis and state space representation of a manipulator under viscoelastic material conditions

    Directory of Open Access Journals (Sweden)

    Esfandiar, H.

    2013-05-01

    Full Text Available In this paper, based on the VoigtKelvin constitutive model, nonlinear dynamic modelling and state space representation of a viscoelastic beam acting as a flexible robotic manipulator is investigated. Complete nonlinear dynamic modelling of a viscoelastic beam without premature linearisation of dynamic equations is developed. The adopted method is capable of reproducing nonlinear dynamic effects, such as beam stiffening due to centrifugal and Coriolis forces induced by rotation of the joints. Structural damping effects on the models dynamic behaviour are also shown. A reliable model for a viscoelastic beam is subsequently presented. The governing equations of motion are derived using Hamiltons principle, and using the finite difference method, nonlinear partial differential equations are reduced to ordinary differential equations. For the purpose of flexible manipulator control, the standard form of state space equations for the viscoelastic link and the actuator is obtained. Simulation results indicate substantial improvements in dynamic behaviour, and a parameter sensitivity study is carried out to investigate the effect of structural damping on the vibration amplitude.

  6. Improving the representation of fire disturbance in dynamic vegetation models by assimilating satellite data

    Science.gov (United States)

    Kantzas, E. P.; Quegan, S.; Lomas, M.

    2015-03-01

    Fire provides an impulsive and stochastic pathway for carbon from the terrestrial biosphere to enter the atmosphere. Despite fire emissions being of similar magnitude to Net Ecosystem Exchange in many biomes, even the most complex Dynamic Vegetation Models (DVMs) embedded in General Circulation Models contain poor representations of fire behaviour and dynamics such as propagation and distribution of fire sizes. A model-independent methodology is developed which addresses this issue. Its focus is on the Arctic where fire is linked to permafrost dynamics and on occasion can release great amounts of carbon from carbon-rich organic soils. Connected Component Labeling is used to identify individual fire events across Canada and Russia from daily, low-resolution burned area satellite products, and the results are validated against historical data. This allows the creation of a fire database holding information on area burned and temporal evolution of fires in space and time. A method of assimilating the statistical distribution of fire area into a DVM whilst maintaining its Fire Return Interval is then described. The algorithm imposes a regional scale spatially dependent fire regime on a sub-scale spatially independent model (point model); the fire regime is described by large scale statistical distributions of fire intensity and spatial extent, and the temporal dynamics (fire return intervals) are determined locally. This permits DVMs to estimate many aspects of post-fire dynamics that cannot occur under their current representations of fire, as is illustrated by considering the evolution of land cover, biomass and Net Ecosystem Exchange after a fire.

  7. Improving the representation of fire disturbance in dynamic vegetation models by assimilating satellite data

    Directory of Open Access Journals (Sweden)

    E. P. Kantzas

    2015-03-01

    Full Text Available Fire provides an impulsive and stochastic pathway for carbon from the terrestrial biosphere to enter the atmosphere. Despite fire emissions being of similar magnitude to Net Ecosystem Exchange in many biomes, even the most complex Dynamic Vegetation Models (DVMs embedded in General Circulation Models contain poor representations of fire behaviour and dynamics such as propagation and distribution of fire sizes. A model-independent methodology is developed which addresses this issue. Its focus is on the Arctic where fire is linked to permafrost dynamics and on occasion can release great amounts of carbon from carbon-rich organic soils. Connected Component Labeling is used to identify individual fire events across Canada and Russia from daily, low-resolution burned area satellite products, and the results are validated against historical data. This allows the creation of a fire database holding information on area burned and temporal evolution of fires in space and time. A method of assimilating the statistical distribution of fire area into a DVM whilst maintaining its Fire Return Interval is then described. The algorithm imposes a regional scale spatially dependent fire regime on a sub-scale spatially independent model (point model; the fire regime is described by large scale statistical distributions of fire intensity and spatial extent, and the temporal dynamics (fire return intervals are determined locally. This permits DVMs to estimate many aspects of post-fire dynamics that cannot occur under their current representations of fire, as is illustrated by considering the evolution of land cover, biomass and Net Ecosystem Exchange after a fire.

  8. Neural dynamics of object-based multifocal visual spatial attention and priming: object cueing, useful-field-of-view, and crowding.

    Science.gov (United States)

    Foley, Nicholas C; Grossberg, Stephen; Mingolla, Ennio

    2012-08-01

    How are spatial and object attention coordinated to achieve rapid object learning and recognition during eye movement search? How do prefrontal priming and parietal spatial mechanisms interact to determine the reaction time costs of intra-object attention shifts, inter-object attention shifts, and shifts between visible objects and covertly cued locations? What factors underlie individual differences in the timing and frequency of such attentional shifts? How do transient and sustained spatial attentional mechanisms work and interact? How can volition, mediated via the basal ganglia, influence the span of spatial attention? A neural model is developed of how spatial attention in the where cortical stream coordinates view-invariant object category learning in the what cortical stream under free viewing conditions. The model simulates psychological data about the dynamics of covert attention priming and switching requiring multifocal attention without eye movements. The model predicts how "attentional shrouds" are formed when surface representations in cortical area V4 resonate with spatial attention in posterior parietal cortex (PPC) and prefrontal cortex (PFC), while shrouds compete among themselves for dominance. Winning shrouds support invariant object category learning, and active surface-shroud resonances support conscious surface perception and recognition. Attentive competition between multiple objects and cues simulates reaction-time data from the two-object cueing paradigm. The relative strength of sustained surface-driven and fast-transient motion-driven spatial attention controls individual differences in reaction time for invalid cues. Competition between surface-driven attentional shrouds controls individual differences in detection rate of peripheral targets in useful-field-of-view tasks. The model proposes how the strength of competition can be mediated, though learning or momentary changes in volition, by the basal ganglia. A new explanation of

  9. Solving dynamic multi-objective problems with vector evaluated particle swarm optimisation

    CSIR Research Space (South Africa)

    Greeff, M

    2008-06-01

    Full Text Available Many optimisation problems are multi-objective and change dynamically. Many methods use a weighted average approach to the multiple objectives. This paper introduces the usage of the vector evaluated particle swarm optimiser (VEPSO) to solve dynamic...

  10. Dynamics of Random Boolean Networks under Fully Asynchronous Stochastic Update Based on Linear Representation

    Science.gov (United States)

    Luo, Chao; Wang, Xingyuan

    2013-01-01

    A novel algebraic approach is proposed to study dynamics of asynchronous random Boolean networks where a random number of nodes can be updated at each time step (ARBNs). In this article, the logical equations of ARBNs are converted into the discrete-time linear representation and dynamical behaviors of systems are investigated. We provide a general formula of network transition matrices of ARBNs as well as a necessary and sufficient algebraic criterion to determine whether a group of given states compose an attractor of length in ARBNs. Consequently, algorithms are achieved to find all of the attractors and basins in ARBNs. Examples are showed to demonstrate the feasibility of the proposed scheme. PMID:23785502

  11. Evaluation of the nondiabaticity of quantum molecular dynamics with the dephasing representation of quantum fidelity

    CERN Document Server

    Zimmermann, Tomas

    2010-01-01

    We propose an approximate method for evaluating the importance of non-Born-Oppenheimer effects on the quantum dynamics of nuclei. The method uses a generalization of the dephasing representation (DR) of quantum fidelity to several diabatic potential energy surfaces and its computational cost is the cost of dynamics of a classical phase space distribution. It can be implemented easily into any molecular dynamics program and also can utilize on-the-fly ab initio electronic structure information. We test the methodology on three model problems introduced by Tully and on the photodissociation of NaI. The results show that for dynamics close to the diabatic regime the decay of fidelity due to nondiabatic effects is described accurately by the DR. In the nearly diabatic regime, unlike the mixed quantum-classical methods such as surface hopping or Ehrenfest dynamics, the DR can capture more subtle quantum effects than the population transfer between potential energy surfaces. Hence we propose using the DR to estimat...

  12. Heterogeneous recurrence representation and quantification of dynamic transitions in continuous nonlinear processes

    Science.gov (United States)

    Chen, Yun; Yang, Hui

    2016-06-01

    Many real-world systems are evolving over time and exhibit dynamical behaviors. In order to cope with system complexity, sensing devices are commonly deployed to monitor system dynamics. Online sensing brings the proliferation of big data that are nonlinear and nonstationary. Although there is rich information on nonlinear dynamics, significant challenges remain in realizing the full potential of sensing data for system control. This paper presents a new approach of heterogeneous recurrence analysis for online monitoring and anomaly detection in nonlinear dynamic processes. A partition scheme, named as Q-tree indexing, is firstly introduced to delineate local recurrence regions in the multi-dimensional continuous state space. Further, we design a new fractal representation of state transitions among recurrence regions, and then develop new measures to quantify heterogeneous recurrence patterns. Finally, we develop a multivariate detection method for on-line monitoring and predictive control of process recurrences. Case studies show that the proposed approach not only captures heterogeneous recurrence patterns in the transformed space, but also provides effective online control charts to monitor and detect dynamical transitions in the underlying nonlinear processes.

  13. A diabatic representation including both valence nonadiabatic interactions and spin-orbit effects for reaction dynamics.

    Science.gov (United States)

    Valero, Rosendo; Truhlar, Donald G

    2007-09-06

    A diabatic representation is convenient in the study of electronically nonadiabatic chemical reactions because the diabatic energies and couplings are smooth functions of the nuclear coordinates and the couplings are scalar quantities. A method called the fourfold way was devised in our group to generate diabatic representations for spin-free electronic states. One drawback of diabatic states computed from the spin-free Hamiltonian, called a valence diabatic representation, for systems in which spin-orbit coupling cannot be ignored is that the couplings between the states are not zero in asymptotic regions, leading to difficulties in the calculation of reaction probabilities and other properties by semiclassical dynamics methods. Here we report an extension of the fourfold way to construct diabatic representations suitable for spin-coupled systems. In this article we formulate the method for the case of even-electron systems that yield pairs of fragments with doublet spin multiplicity. For this type of system, we introduce the further simplification of calculating the triplet diabatic energies in terms of the singlet diabatic energies via Slater's rules and assuming constant ratios of Coulomb to exchange integrals. Furthermore, the valence diabatic couplings in the triplet manifold are taken equal to the singlet ones. An important feature of the method is the introduction of scaling functions, as they allow one to deal with multibond reactions without having to include high-energy diabatic states. The global transformation matrix to the new diabatic representation, called the spin-valence diabatic representation, is constructed as the product of channel-specific transformation matrices, each one taken as the product of an asymptotic transformation matrix and a scaling function that depends on ratios of the spin-orbit splitting and the valence splittings. Thus the underlying basis functions are recoupled into suitable diabatic basis functions in a manner that

  14. A Novel Approach for Moving Object Detection from Dynamic Background

    Directory of Open Access Journals (Sweden)

    Ms. Pinky R. Rathod,

    2015-03-01

    Full Text Available In computer vision application, moving object detection is the key technology for intelligent video monitoring system. Performance of an automated visual surveillance system considerably depends on its ability to detect moving objects in thermodynamic environment. A subsequent action, such as tracking, analyzing the motion or identifying objects, requires an accurate extraction of the foreground objects, making moving object detection a crucial part of the system. The aim of this paper is to detect real moving objects from un-stationary background regions (such as branches and leafs of a tree or a flag waving in the wind, limiting false negatives (objects pixels that are not detected as much as possible. In addition, it is assumed that the models of the target objects and their motion are unknown, so as to achieve maximum application independence (i.e. algorithm works under the non-prior training.

  15. Objects, Signs, and Representations in the Semio-Cognitive Analysis of the Processes Involved in Teaching and Learning Mathematics: A Duvalian Perspective

    Science.gov (United States)

    Iori, Maura

    2017-01-01

    In mathematical activities and in the analysis of mathematics teaching-learning processes, "objects," "signs", and "representations" are often mentioned, where the meaning assigned to those words is sometimes very broad, sometimes limited, other times intuitive, allusive, or not completely clear. On the other hand, as…

  16. Testing Accommodation or Modification?: The Effects of Integrated Object Representation on Enhancing Geometry Performance in Children with and without Geometry Difficulties

    Science.gov (United States)

    Zhang, Dake; Wang, Qiu; Ding, Yi; Liu, Jeremy Jian

    2014-01-01

    According to the National Council of Teachers of Mathematics, geometry and spatial sense are fundamental components of mathematics learning. However, learning disabilities (LD) research has shown that many K-12 students encounter particular geometry difficulties (GD). This study examined the effect of an integrated object representation (IOR)…

  17. Objects, Signs, and Representations in the Semio-Cognitive Analysis of the Processes Involved in Teaching and Learning Mathematics: A Duvalian Perspective

    Science.gov (United States)

    Iori, Maura

    2017-01-01

    In mathematical activities and in the analysis of mathematics teaching-learning processes, "objects," "signs", and "representations" are often mentioned, where the meaning assigned to those words is sometimes very broad, sometimes limited, other times intuitive, allusive, or not completely clear. On the other hand, as…

  18. Shape similarity, better than semantic membership, accounts for the structure of visual object representations in a population of monkey inferotemporal neurons.

    Science.gov (United States)

    Baldassi, Carlo; Alemi-Neissi, Alireza; Pagan, Marino; Dicarlo, James J; Zecchina, Riccardo; Zoccolan, Davide

    2013-01-01

    The anterior inferotemporal cortex (IT) is the highest stage along the hierarchy of visual areas that, in primates, processes visual objects. Although several lines of evidence suggest that IT primarily represents visual shape information, some recent studies have argued that neuronal ensembles in IT code the semantic membership of visual objects (i.e., represent conceptual classes such as animate and inanimate objects). In this study, we investigated to what extent semantic, rather than purely visual information, is represented in IT by performing a multivariate analysis of IT responses to a set of visual objects. By relying on a variety of machine-learning approaches (including a cutting-edge clustering algorithm that has been recently developed in the domain of statistical physics), we found that, in most instances, IT representation of visual objects is accounted for by their similarity at the level of shape or, more surprisingly, low-level visual properties. Only in a few cases we observed IT representations of semantic classes that were not explainable by the visual similarity of their members. Overall, these findings reassert the primary function of IT as a conveyor of explicit visual shape information, and reveal that low-level visual properties are represented in IT to a greater extent than previously appreciated. In addition, our work demonstrates how combining a variety of state-of-the-art multivariate approaches, and carefully estimating the contribution of shape similarity to the representation of object categories, can substantially advance our understanding of neuronal coding of visual objects in cortex.

  19. Vestibular stimulation interferes with the dynamics of an internal representation of gravity.

    Science.gov (United States)

    De Sá Teixeira, Nuno Alexandre; Hecht, Heiko; Diaz Artiles, Ana; Seyedmadani, Kimia; Sherwood, David P; Young, Laurence R

    2017-11-01

    The remembered vanishing location of a moving target has been found to be displaced downward in the direction of gravity (representational gravity) and more so with increasing retention intervals, suggesting that the visual spatial updating recruits an internal model of gravity. Despite being consistently linked with gravity, few inquiries have been made about the role of vestibular information in these trends. Previous experiments with static tilting of observers' bodies suggest that under conflicting cues between the idiotropic vector and vestibular signals, the dynamic drift in memory is reduced to a constant displacement along the body's main axis. The present experiment aims to replicate and extend these outcomes while keeping the observers' bodies unchanged in relation to physical gravity by varying the gravito-inertial acceleration using a short-radius centrifuge. Observers were shown, while accelerated to varying degrees, targets moving along several directions and were required to indicate the perceived vanishing location after a variable interval. Increases of the gravito-inertial force (up to 1.4G), orthogonal to the idiotropic vector, did not affect the direction of representational gravity, but significantly disrupted its time course. The role and functioning of an internal model of gravity for spatial perception and orientation are discussed in light of the results.

  20. Dynamics of trimming the content of face representations for categorization in the brain.

    Directory of Open Access Journals (Sweden)

    Nicola J van Rijsbergen

    2009-11-01

    Full Text Available To understand visual cognition, it is imperative to determine when, how and with what information the human brain categorizes the visual input. Visual categorization consistently involves at least an early and a late stage: the occipito-temporal N170 event related potential related to stimulus encoding and the parietal P300 involved in perceptual decisions. Here we sought to understand how the brain globally transforms its representations of face categories from their early encoding to the later decision stage over the 400 ms time window encompassing the N170 and P300 brain events. We applied classification image techniques to the behavioral and electroencephalographic data of three observers who categorized seven facial expressions of emotion and report two main findings: (1 over the 400 ms time course, processing of facial features initially spreads bilaterally across the left and right occipito-temporal regions to dynamically converge onto the centro-parietal region; (2 concurrently, information processing gradually shifts from encoding common face features across all spatial scales (e.g., the eyes to representing only the finer scales of the diagnostic features that are richer in useful information for behavior (e.g., the wide opened eyes in 'fear'; the detailed mouth in 'happy'. Our findings suggest that the brain refines its diagnostic representations of visual categories over the first 400 ms of processing by trimming a thorough encoding of features over the N170, to leave only the detailed information important for perceptual decisions over the P300.

  1. Non-Markovian reduced dynamics based upon a hierarchical effective-mode representation

    Energy Technology Data Exchange (ETDEWEB)

    Burghardt, Irene [Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt (Germany); Martinazzo, Rocco [Dipartimento di Chimica, Universita degli Studi di Milano, v. Golgi 19, 20133 Milano (Italy); Hughes, Keith H. [School of Chemistry, Bangor University, Bangor, Gwynedd LL57 2UW (United Kingdom)

    2012-10-14

    A reduced dynamics representation is introduced which is tailored to a hierarchical, Mori-chain type representation of a bath of harmonic oscillators which are linearly coupled to a subsystem. We consider a spin-boson system where a single effective mode is constructed so as to absorb all system-environment interactions, while the residual bath modes are coupled bilinearly to the primary mode and among each other. Using a cumulant expansion of the memory kernel, correlation functions for the primary mode are obtained, which can be suitably approximated by truncated chains representing the primary-residual mode interactions. A series of reduced-dimensional bath correlation functions is thus obtained, which can be expressed as Fourier-Laplace transforms of spectral densities that are given in truncated continued-fraction form. For a master equation which is second order in the system-bath coupling, the memory kernel is re-expressed in terms of local-in-time equations involving auxiliary densities and auxiliary operators.

  2. Dynamics of Trimming the Content of Face Representations for Categorization in the Brain

    Science.gov (United States)

    van Rijsbergen, Nicola J.; Schyns, Philippe G.

    2009-01-01

    To understand visual cognition, it is imperative to determine when, how and with what information the human brain categorizes the visual input. Visual categorization consistently involves at least an early and a late stage: the occipito-temporal N170 event related potential related to stimulus encoding and the parietal P300 involved in perceptual decisions. Here we sought to understand how the brain globally transforms its representations of face categories from their early encoding to the later decision stage over the 400 ms time window encompassing the N170 and P300 brain events. We applied classification image techniques to the behavioral and electroencephalographic data of three observers who categorized seven facial expressions of emotion and report two main findings: (1) over the 400 ms time course, processing of facial features initially spreads bilaterally across the left and right occipito-temporal regions to dynamically converge onto the centro-parietal region; (2) concurrently, information processing gradually shifts from encoding common face features across all spatial scales (e.g., the eyes) to representing only the finer scales of the diagnostic features that are richer in useful information for behavior (e.g., the wide opened eyes in ‘fear’; the detailed mouth in ‘happy’). Our findings suggest that the brain refines its diagnostic representations of visual categories over the first 400 ms of processing by trimming a thorough encoding of features over the N170, to leave only the detailed information important for perceptual decisions over the P300. PMID:19911045

  3. Representation and coding of large-scale 3D dynamic maps

    Science.gov (United States)

    Cohen, Robert A.; Tian, Dong; Krivokuća, Maja; Sugimoto, Kazuo; Vetro, Anthony; Wakimoto, Koji; Sekiguchi, Shunichi

    2016-09-01

    combined with depth and color measurements of the surrounding environment. Localization could be achieved with GPS, inertial measurement units (IMU), cameras, or combinations of these and other devices, while the depth measurements could be achieved with time-of-flight, radar or laser scanning systems. The resulting 3D maps, which are composed of 3D point clouds with various attributes, could be used for a variety of applications, including finding your way around indoor spaces, navigating vehicles around a city, space planning, topographical surveying or public surveying of infrastructure and roads, augmented reality, immersive online experiences, and much more. This paper discusses application requirements related to the representation and coding of large-scale 3D dynamic maps. In particular, we address requirements related to different types of acquisition environments, scalability in terms of progressive transmission and efficiently rendering different levels of details, as well as key attributes to be included in the representation. Additionally, an overview of recently developed coding techniques is presented, including an assessment of current performance. Finally, technical challenges and needs for future standardization are discussed.

  4. Relativistic Dirac Representation of Dynamically-Generated Elementary-Particle Mass

    CERN Document Server

    Chew, Geoffrey F

    2008-01-01

    Special-relativistic dynamically-generated elementary-particle mass is represented by a self-adjoint energy operator acting on a rigged Hilbert space (RHS) of functions over the 6-dimensional Euclidean-group manifold. Even though this operator's eigenvalues correspond to total energy, it is not the generator of infinitesimal wave-function evolution in classical time. Extending formalism which Dirac invented and applied non-relativistically, unitary Poincar\\'e-group representation is provided by the wave functions of a spacelike entity that we call "preon". Six continuous Feynman-path-contacting preon coordinates specify spatial location (3 coordinates), lightlike-velocity-direction (2 coordinates) and transverse polarization (1 coordinate). [Utility of the the term "preon observable" is dubious.] Velocity and spatial location collaborate to define a preon time operator conjugate to the energy operator. In RHS bases alternative to functions over the group manifold, the wave function depends on a preon "velocit...

  5. Light-front representation of chiral dynamics with Delta isobar and large-N_c relations

    CERN Document Server

    Granados, C

    2016-01-01

    Transverse densities describe the spatial distribution of electromagnetic current in the nucleon at fixed light-front time. At peripheral distances b = O(M_pi^{-1}) the densities are governed by chiral dynamics and can be calculated model-independently using chiral effective field theory (EFT). Recent work has shown that the EFT results can be represented in first-quantized form, as overlap integrals of chiral light-front wave functions describing the transition of the nucleon to soft-pion-nucleon intermediate states, resulting in a quantum-mechanical picture of the peripheral transverse densities. We now extend this representation to include intermediate states with Delta isobars and implement relations based on the large-N_c limit of QCD. We derive the wave function overlap formulas for the Delta contributions to the peripheral transverse densities by way of a three-dimensional reduction of relativistic chiral EFT expressions. Our procedure effectively maintains rotational invariance and avoids the ambiguit...

  6. Non-adiabatic molecular dynamics with complex quantum trajectories. I. The diabatic representation.

    Science.gov (United States)

    Zamstein, Noa; Tannor, David J

    2012-12-14

    We extend a recently developed quantum trajectory method [Y. Goldfarb, I. Degani, and D. J. Tannor, J. Chem. Phys. 125, 231103 (2006)] to treat non-adiabatic transitions. Each trajectory evolves on a single surface according to Newton's laws with complex positions and momenta. The transfer of amplitude between surfaces stems naturally from the equations of motion, without the need for surface hopping. In this paper we derive the equations of motion and show results in the diabatic representation, which is rarely used in trajectory methods for calculating non-adiabatic dynamics. We apply our method to the first two benchmark models introduced by Tully [J. Chem. Phys. 93, 1061 (1990)]. Besides giving the probability branching ratios between the surfaces, the method also allows the reconstruction of the time-dependent wavepacket. Our results are in quantitative agreement with converged quantum mechanical calculations.

  7. Object Oriented Toolbox for Modelling and Simulation of Dynamic Systems

    DEFF Research Database (Denmark)

    Thomsen, Per Grove; Poulsen, Mikael Zebbelin; Wagner, Falko Jens;

    1999-01-01

    Design and Implementation of a simulation toolbox based on Object Oriented modelling Techniques.Experimental implementation in C++ using the Godess ODE-solution platform.......Design and Implementation of a simulation toolbox based on Object Oriented modelling Techniques.Experimental implementation in C++ using the Godess ODE-solution platform....

  8. On process model representation and AlF{sub 3} dynamics of aluminium electrolysis cells

    Energy Technology Data Exchange (ETDEWEB)

    Drengstig, Tormod

    1997-12-31

    This thesis develops a formal graphical based process representation scheme for modelling complex, non-standard unit processes. The scheme is based on topological and phenomenological decompositions. The topological decomposition is the modularization of processes into modules representing volumes and boundaries, whereas the phenomenological decomposition focuses on physical phenomena and characteristics inside these topological modules. This defines legal and illegal connections between components at all levels and facilitates a full implementation of the methodology into a computer aided modelling tool that can interpret graphical symbols and guide modelers towards a consistent mathematical model of the process. The thesis also presents new results on the excess AlF{sub 3} and bath temperature dynamics of an aluminium electrolysis cell. A dynamic model of such a cell is developed and validated against known behaviour and real process data. There are dynamics that the model does not capture and this is further discussed. It is hypothesized that long-term prediction of bath temperature and excess AlF{sub 3} is impossible with a current efficiency model considering only bath composition and temperature. A control strategy for excess AlF{sub 3} and bath temperature is proposed based on an almost constant AlF{sub 3} input close to average consumption and energy manipulations to compensate for the disturbances. 96 refs., 135 figs., 22 tabs.

  9. Object texture recognition by dynamic tactile sensing using active exploration

    DEFF Research Database (Denmark)

    Drimus, Alin; Børlum Petersen, Mikkel; Bilberg, Arne

    For both humans and robots, tactile sensing is important for interaction with the environment: it is the core sensing used for exploration and manipulation of objects. In this paper, we present a method for determining object texture by active exploration with a robotic fingertip equipped with a d...... features and performance of learning algorithms is done and the best method is further used to classify objects by their surface textures with recognition results higher than 90 percent.......For both humans and robots, tactile sensing is important for interaction with the environment: it is the core sensing used for exploration and manipulation of objects. In this paper, we present a method for determining object texture by active exploration with a robotic fingertip equipped...

  10. How important is a detailed hydrological representation when modelling soil carbon dynamics in Chinese red soils.

    Science.gov (United States)

    Oyesiku-Blakemore, Joseph; Verrot, Lucile; Geris, Josie; Zhang, Ganlin; Peng, Xinhua; Hallett, Paul; Smith, Jo

    2017-04-01

    Soil carbon and nitrogen processing are strongly influenced by the hydrology of soils. When simulating these processes models represent soil hydrology in some way. The hydrological components of soil carbon and nitrogen models vary greatly in their complexity, as does the burden of simulation time and data requirements. Hydrology specific models, such as Hydrus, have more detailed representations of soil hydrology than those used in some soil carbon and nitrogen models, such as ECOSSE, and can provide a more accurate and precise description of the movement and content of water in soil. Moisture content is one of the key variables controlling the processing of carbon and nitrogen in soil models. A higher soil moisture content results in increased methane production through the anaerobic decomposition of soil carbon pools. It also alters the rate at which aerobic decomposition occurs, with low and high soil moisture contents limiting the decomposition of SOC. An inaccurate estimate of soil moisture will introduce errors in the estimated rates of model SOC transformations, which would result in errors in the simulated SOC. In order to shed light on this uncertainty we use the same input data to simulate soil moisture contents in a Red Soil region of China, using both the ECOSSE model and Hydrus 2D. We compare the simulations of both models with measurements of soil moisture at the site and each other. We highlight where the models differ and identify the conditions under which errors are likely to occur. We then simulate SOC dynamics using the ECOSSE model and its original hydrology with the ECOSSE model simulations using the Hydrus 2D simulations. This shows the importance of including a detailed representation of soil moisture when simulating soil organic matter dynamics.

  11. Optimal Estimator Synthesis for Ship Dynamic Object Control

    OpenAIRE

    BIYA MOTTO Frederic

    2014-01-01

    Optimal estimator synthesis algorithm for dynamic ship system control is considered. Estimator is constructed in the form of Kalman gain as steady-state Kalman filter. Estimator design is realised by MATLAB codes using account of wind gust noise with a set spectral intensity

  12. No Evidence for a Fixed Object Limit in Working Memory: Spatial Ensemble Representations Inflate Estimates of Working Memory Capacity for Complex Objects

    Science.gov (United States)

    Brady, Timothy F.; Alvarez, George A.

    2015-01-01

    A central question for models of visual working memory is whether the number of objects people can remember depends on object complexity. Some influential "slot" models of working memory capacity suggest that people always represent 3-4 objects and that only the fidelity with which these objects are represented is affected by object…

  13. The Time Diagram Control Approach for the Dynamic Representation of Time-Oriented Data

    Directory of Open Access Journals (Sweden)

    Rolf Dornberger

    2016-04-01

    Full Text Available The dynamic representation of time-oriented data on small screen devices is of increasing importance. Most solution approaches use issue-specific requirements based on established desktop technologies. Applied to mobile devices with small multi-touch displays such approaches often lead to a limited usability. Particularly, the time-dependent data can only be fragmentarily visualized due to limited screen sizes. Instead of reducing the complexity by visualizing the data, the interpretation of the data is getting more complex. This paper proposes a Time Diagram Control (TDC approach, a new way of representing time-based diagrams on small screen devices. The TDC uses a principle of cybernetics to integrate the user in the visualization process and thus reduce complexity. TDC focuses on simplicity of design by only providing 2D temporal line diagrams with a dynamic zooming function that works via standard multi-touch controls. Involving the user into a continuous loop of refining the visualization, TDC allows to compare data of different temporal granularities without losing the overall context of the presented data. The TDC approach ensures constant information reliability on small screen devices.

  14. On the Dynamics of Resonant Kuiper Belt Objects

    CERN Document Server

    Jiang, I G; Jiang, Ing-Guey; Yeh, Li-Chin

    2007-01-01

    We propose a new mechanism of drag-induced resonant capture, which can explain the resonant Kuiper Belt Objects in a natural way. A review and comparison with the traditional mechanism of sweeping capture by the migrating Neptune will be given.

  15. Object Oriented Toolbox for Modelling and Simulation of Dynamical Systems

    DEFF Research Database (Denmark)

    Poulsen, Mikael Zebbelin; Wagner, Falko Jens; Thomsen, Per Grove

    1998-01-01

    This paper presents the results of an ongoing project, dealing with design and implementation of a simulation toolbox based on object oriented modelling techniques. The paper describes an experimental implementation of parts of such a toolbox in C++, and discusses the experiences drawn from...

  16. An objective method for High Dynamic Range source content selection

    DEFF Research Database (Denmark)

    Narwaria, Manish; Mantel, Claire; Da Silva, Matthieu Perreira

    2014-01-01

    component of such validation studies is the selection of a challenging and balanced set of source (reference) HDR content. In order to facilitate this, we present an objective method based on the premise that a more challenging HDR scene encapsulates higher contrast, and as a result will show up more...

  17. REPRESENTATION OF THE DISEASE, THE MOTIVATIONAL SPHERE AND MEDICAL COMMUNICATION AS AN OBJECTIVE FOR HIV PREVENTION AND THE TREATMENT OF HIV INFECTION IN SUBSTANCE USERS

    OpenAIRE

    Buzina, Tatiana

    2014-01-01

    The psychological aspect of treating HIV-infected substance users entails changing their behaviour, as their behaviour is what leads to the risk of them transmitting and spreading HIV. Psychological treatment must facilitate their adaptation so that they may be otherwise treated for substance abuse and HIV. We propose establishing the psychological objective of helping patients overcome substance addiction by addressing their internal representation of the disease (IRD), value-sense and motiv...

  18. Musical Objects, Cross-Domain Correspondences, and Cultural Choice: Commentary on “Cross-Cultural Representations of Musical Shape” by George Athanasopoulos and Nikki Moran

    Directory of Open Access Journals (Sweden)

    Zohar Eitan

    2013-12-01

    Full Text Available The target article illustrates deep cross-cultural gaps, involving not only the representation of musical shape but also the notion of a musical object itself. Yet, numerous empirical findings suggest that important cross-modal correspondences involving music and visual dimensions are inborn or learned at infancy, prior to the acquisition of language and most culture-specific behavior. Drawing on recent empirical work, the commentary attempts to reconcile this apparent disparity.

  19. Shape similarity, better than semantic membership, accounts for the structure of visual object representations in a population of monkey inferotemporal neurons.

    Directory of Open Access Journals (Sweden)

    Carlo Baldassi

    Full Text Available The anterior inferotemporal cortex (IT is the highest stage along the hierarchy of visual areas that, in primates, processes visual objects. Although several lines of evidence suggest that IT primarily represents visual shape information, some recent studies have argued that neuronal ensembles in IT code the semantic membership of visual objects (i.e., represent conceptual classes such as animate and inanimate objects. In this study, we investigated to what extent semantic, rather than purely visual information, is represented in IT by performing a multivariate analysis of IT responses to a set of visual objects. By relying on a variety of machine-learning approaches (including a cutting-edge clustering algorithm that has been recently developed in the domain of statistical physics, we found that, in most instances, IT representation of visual objects is accounted for by their similarity at the level of shape or, more surprisingly, low-level visual properties. Only in a few cases we observed IT representations of semantic classes that were not explainable by the visual similarity of their members. Overall, these findings reassert the primary function of IT as a conveyor of explicit visual shape information, and reveal that low-level visual properties are represented in IT to a greater extent than previously appreciated. In addition, our work demonstrates how combining a variety of state-of-the-art multivariate approaches, and carefully estimating the contribution of shape similarity to the representation of object categories, can substantially advance our understanding of neuronal coding of visual objects in cortex.

  20. Interactive Correspondence Analysis in a Dynamic Object-Oriented Environment

    Directory of Open Access Journals (Sweden)

    Jason Bond

    1997-11-01

    Full Text Available A highly interactive, user-friendly object-oriented software package written in LispStat is introduced that performs simple and multiple correspondence analysis, and profile analysis. These three techniques are integrated into a single environment driven by a user-friendly graphical interface that takes advantage of Lisp-Stat's advanced graphical capabilities. Techniques that assess the stability of the solution are also introduced. Some of the features of the package include colored graphics, incremental graph zooming capabilities, manual point separation to determine identities of overlapping points, and stability and fit measures. The features of the package are used to show some interesting trends in a large educational dataset.

  1. An evaluation of a simple dynamical model for impacts between rigid objects

    OpenAIRE

    Molino Minero, Erik; López García, Mariano; Manuel Lázaro, Antonio; Carlosena García, Alfonso; Roset Juan, Francesc Xavier

    2009-01-01

    The main purpose of this work is to propose a dynamical model for simulating the response of different metallic objects when impacted by another rigid body. In addition, a methodology for estimating the model parameters is presented and discussed. Results from real experiments shows that by assuming certain characteristics on impacting objects, the dynamic model can reproduce the transient dynamics during contact time. Peer Reviewed

  2. A state space representation of VAR models with sparse learning for dynamic gene networks.

    Science.gov (United States)

    Kojima, Kaname; Yamaguchi, Rui; Imoto, Seiya; Yamauchi, Mai; Nagasaki, Masao; Yoshida, Ryo; Shimamura, Teppei; Ueno, Kazuko; Higuchi, Tomoyuki; Gotoh, Noriko; Miyano, Satoru

    2010-01-01

    We propose a state space representation of vector autoregressive model and its sparse learning based on L1 regularization to achieve efficient estimation of dynamic gene networks based on time course microarray data. The proposed method can overcome drawbacks of the vector autoregressive model and state space model; the assumption of equal time interval and lack of separation ability of observation and systems noises in the former method and the assumption of modularity of network structure in the latter method. However, in a simple implementation the proposed model requires the calculation of large inverse matrices in a large number of times during parameter estimation process based on EM algorithm. This limits the applicability of the proposed method to a relatively small gene set. We thus introduce a new calculation technique for EM algorithm that does not require the calculation of inverse matrices. The proposed method is applied to time course microarray data of lung cells treated by stimulating EGF receptors and dosing an anticancer drug, Gefitinib. By comparing the estimated network with the control network estimated using non-treated lung cells, perturbed genes by the anticancer drug could be found, whose up- and down-stream genes in the estimated networks may be related to side effects of the anticancer drug.

  3. Dynamic visualization in a developing framework for the representation of geographic data

    Directory of Open Access Journals (Sweden)

    Connie Blok

    2000-11-01

    Full Text Available In order to translate the characteristics of geographic data into signs and signals that can be perceived from a map, a language consisting of building blocks and a syntax are required. The first language to be developed was a graphic sign language, introduced by Bertin. His framework has been adapted and extended. It now includes languages for other senses, like touch and hearing, and even smell and taste are currently being investigated. In this paper it has been argued that the overall framework is continuously growing under the influence of technological, conceptual and user-oriented developments. Technological developments in particular are rapid. For example, they allow the representation of geographic data in virtual environments, which can be experienced through multiple senses. If cartographers want to play a role here, they should be willing to contribute to further extension of the framework, which may never be complete. In addition, current definitions of the concepts 'cartography' and 'map' have to be adapted. An example of user-oriented developments is the growing awareness of different types of map use, ranging from presentation to analysis/exploration. Application of the sign language may be different for each type of use, so the framework also needs further development in this direction. As an example, research ideas with respect to the use of dynamic visualization variables in cartographic animations for exploration purposes are included.

  4. Dynamic interactions and competing objectives in multifamily green building design

    Energy Technology Data Exchange (ETDEWEB)

    Snell, J. [Peregrine Energy Group, Boston, MA (United States); Neuhauser, K. [Conservation Services Group, Inc., Westborough, MA (United States)

    2005-07-01

    This paper describes the challenges involved in the construction of a mid-rise housing development in Boston, Massachusetts, during which the development team elected to upgrade the initial design criteria from Minimum Building Code to Energy Star and Leadership in Energy and Environmental Design (LEED) certification. The various constraints imposed on the development were discussed, including constraints imposed by the involvement of substantial public funds as well as the constraints imposed by various funding sources that were approached to leverage energy efficiency and green building investment via competitive grant solicitations. Building owner and utility cost management priorities were outlined along with details of central mechanical system selection. Issues concerning isolation and compartmentalization were examined along with indoor pollution source control. A building load analysis was presented as well as details of daily heating and cooling statistics. Electric generation system integration issues were also presented. It was concluded that the constraints of the project and conditions of targeted assistance ultimately impeded full integration of the design. As a result, some measures appeared to work at cross-purposes with other objectives. Despite many challenges, the development team made significant progress towards optimization within the realistic constraints of the subsidized housing industry. 4 refs., 4 tabs., 4 figs.

  5. Translational systems biology using an agent-based approach for dynamic knowledge representation: An evolutionary paradigm for biomedical research.

    Science.gov (United States)

    An, Gary C

    2010-01-01

    The greatest challenge facing the biomedical research community is the effective translation of basic mechanistic knowledge into clinically effective therapeutics. This challenge is most evident in attempts to understand and modulate "systems" processes/disorders, such as sepsis, cancer, and wound healing. Formulating an investigatory strategy for these issues requires the recognition that these are dynamic processes. Representation of the dynamic behavior of biological systems can aid in the investigation of complex pathophysiological processes by augmenting existing discovery procedures by integrating disparate information sources and knowledge. This approach is termed Translational Systems Biology. Focusing on the development of computational models capturing the behavior of mechanistic hypotheses provides a tool that bridges gaps in the understanding of a disease process by visualizing "thought experiments" to fill those gaps. Agent-based modeling is a computational method particularly well suited to the translation of mechanistic knowledge into a computational framework. Utilizing agent-based models as a means of dynamic hypothesis representation will be a vital means of describing, communicating, and integrating community-wide knowledge. The transparent representation of hypotheses in this dynamic fashion can form the basis of "knowledge ecologies," where selection between competing hypotheses will apply an evolutionary paradigm to the development of community knowledge.

  6. Topographic representations of object size and relationships with numerosity reveal generalized quantity processing in human parietal cortex

    NARCIS (Netherlands)

    Harvey, Ben M|info:eu-repo/dai/nl/318755319; Fracasso, Alessio|info:eu-repo/dai/nl/372646905; Petridou, Natalia; Dumoulin, Serge O|info:eu-repo/dai/nl/314406514

    2015-01-01

    Humans and many animals analyze sensory information to estimate quantities that guide behavior and decisions. These quantities include numerosity (object number) and object size. Having recently demonstrated topographic maps of numerosity, we ask whether the brain also contains maps of object size.

  7. A Dynamic Object Behavior Model and Implementation Based on Computational Reflection

    Institute of Scientific and Technical Information of China (English)

    HE Cheng-wan; HE Fei; HE Ke-qing

    2005-01-01

    A dynamic object behavior model based on computational reflection is proposed. This model consists of function level and meta level, the meta objects in meta level manage the base objects and behaviors in function level, including dynamic binding and unbinding of base object and behavior.We implement this model with RoleJava Language, which is our self linguistic extension of the Java Language. Meta Objects are generated automatically at compile-time, this makes the reflecton mechanism transparent to programmers. Finally an example applying this model to a banking system is presented.

  8. Keep away from danger: Dangerous objects in dynamic and static situations

    Directory of Open Access Journals (Sweden)

    Filomena eAnelli

    2013-07-01

    Full Text Available Behavioral and neuroscience studies have shown that objects observation evokes specific affordances (i.e., action possibilities and motor responses. Recent findings provide evidence that even dangerous objects can modulate the motor system evoking aversive affordances. This sounds intriguing since so far the majority of behavioral, brain imaging, and transcranial magnetic stimulation studies with painful and dangerous stimuli strictly concerned the domain of pain, excepted for evidence suggesting sensitivity to objects’ affordances when neutral objects are located in participants’ peripersonal space. This study investigates whether the observation of a neutral or dangerous object in a static or dynamic situation differently influences motor responses, and the time-course of the dangerous objects’ processing. In three experiments we manipulated: object dangerousness (neutral vs. dangerous; object category (artifact vs. natural; manual response typology (press vs. release a key; object presentation (Experiment 1: dynamic, Experiments 2 and 3: static; object movement direction (Experiment 1: away vs. toward the participant or size (Experiments 2 and 3: big vs. normal vs. small. The task required participants to decide whether the object was an artifact or a natural object, by pressing or releasing one key. Results showed a facilitation for neutral over dangerous objects in the static situation, probably due to an affordance effect. Instead, in the dynamic condition responses were modulated by the object movement direction, with a dynamic affordance effect of neutral objects and an escape-avoidance effect of dangerous objects (neutral objects were processed faster when they moved toward-approached the participant, whereas dangerous objects were processed faster when they moved away from the participant. Moreover, static stimuli influenced the manual response typology. These data indicate the emergence of dynamic affordance and escaping

  9. Light-front representation of chiral dynamics with Δ isobar and large- N c relations

    Science.gov (United States)

    Granados, C.; Weiss, C.

    2016-06-01

    Transverse densities describe the spatial distribution of electromagnetic current in the nucleon at fixed light-front time. At peripheral distances b = O( M π - 1 ) the densities are governed by chiral dynamics and can be calculated model-independently using chiral effective field theory (EFT). Recent work has shown that the EFT results can be represented in first-quantized form, as overlap integrals of chiral light-front wave functions describing the transition of the nucleon to soft-pion-nucleon intermediate states, resulting in a quantum-mechanical picture of the peripheral transverse densities. We now extend this representation to include intermediate states with Δ isobars and implement relations based on the large- N c limit of QCD. We derive the wave function overlap formulas for the Δ contributions to the peripheral transverse densities by way of a three-dimensional reduction of relativistic chiral EFT expressions. Our procedure effectively maintains rotational invariance and avoids the ambiguities with higher-spin particles in the light-front time-ordered approach. We study the interplay of π N and πΔ intermediate states in the quantum-mechanical picture of the densities in a transversely polarized nucleon. We show that the correct N c -scaling of the charge and magnetization densities emerges as the result of the particular combination of currents generated by intermediate states with degenerate N and Δ. The off-shell behavior of the chiral EFT is summarized in contact terms and can be studied easily. The methods developed here can be applied to other peripheral densities and to moments of the nucleon's generalized parton distributions.

  10. Object permanence in the food-storing coal tit (Periparus ater) and the non-storing great tit (Parus major): Is the mental representation required?

    Science.gov (United States)

    Marhounová, Lucie; Frynta, Daniel; Fuchs, Roman; Landová, Eva

    2017-05-01

    Object permanence is a cognitive ability that enables animals to mentally represent the continuous existence of temporarily hidden objects. Generally, it develops gradually through six qualitative stages, the evolution of which may be connected with some specific ecological and behavioral factors. In birds, the advanced object permanence skills were reported in several storing species of the Corvidae family. In order to test the association between food-storing and achieved performance within the stages, we compared food-storing coal tits (Periparus ater) and nonstoring great tits (Parus major) using an adapted version of Uzgiris & Hunt's Scale 1 tasks. The coal tits significantly outperformed the great tits in searching for completely hidden objects. Most of the great tits could not solve the task when the object disappeared completely. However, the upper limit for both species is likely to be Stage 4. The coal tits could solve problems with simply hidden objects, but they used alternative strategies rather than mental representation when searching for completely hidden objects, especially if choosing between two locations. Our results also suggest that neophobia did not affect the overall performance in the object permanence tasks. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  11. From static to dynamic use of knowledge transfer objects and its effect on innovation performance

    DEFF Research Database (Denmark)

    Sajadirad, Solmaz; Lassen, Astrid Heidemann; Wæhrens, Brian Vejrum

    2016-01-01

    multinational companies located in Denmark. Based on literature review and empirical evidence, we discuss that inter-firm objects can be considered as boundary objects if they support specific circumstances, i.e., interactions and negotiations, collaboration, shared understanding and identity......, and transformation of knowledge. Additionally, we argue that dynamic use of knowledge transfer objects, referred to as boundary objects, can lead to a higher degree of innovation performance for headquarters...

  12. Real-Time Projection-Based Augmented Reality System for Dynamic Objects in the Performing Arts

    National Research Council Canada - National Science Library

    Jaewoon Lee; Yeonjin Kim; Myeong-Hyeon Heo; Dongho Kim; Byeong-Seok Shin

    2015-01-01

    ... say real-time projection-based augmented reality system for dynamic objects in performing arts. We installed the sets on a stage for live performance, and rehearsed particular scenes of a musical...

  13. Spacecraft Proximity Operations Used to Estimate the Dynamical & Physical Properties of a Resident Space Object

    Science.gov (United States)

    2007-03-01

    Document, 2006. 26. D. Mehrholz, W. Flury R. Jehn H. Klinkrad M. Landgraf, L. Leushacke. “De- tecting, Tracking and Imaging Space Debris ”. Eurpean Space ...SPACECRAFT PROXIMITY OPERATIONS USED TO ESTIMATE THE DYNAMICAL & PHYSICAL PROPERTIES OF A RESIDENT SPACE OBJECT THESIS Abraham Franz Brunner, First...OPERATIONS USED TO ESTIMATE THE DYNAMICAL & PHYSICAL PROPERTIES OF A RESIDENT SPACE OBJECT THESIS Presented to the Faculty Department of Aeronautics and

  14. To bind or not to bind: addressing the question of object representation in visual short-term memory.

    Science.gov (United States)

    Wilson, Kristin E; Adamo, Maha; Barense, Morgan D; Ferber, Susanne

    2012-01-01

    Visual short-term memory (VSTM) is a capacity limited resource, which is consistently estimated to hold about four visual items at a time. There is, however, debate in the literature about what constitutes an "item" and how resources are allocated within VSTM. Some research suggests information is stored in VSTM as discrete objects; however, there is also evidence suggesting that within-object features alter VSTM performance. The present study addresses the question of whether VSTM load effects reflect the number of discrete objects and/or the number of within-object features. An electrophysiological correlate of VSTM--the contralateral delay activity (CDA)--was measured while participants performed a lateralized change-detection task, in which to-be-remembered items varied in the number of features and locations. Each trial contained either a solitary simple feature (shape, color, or orientation) or one of two multifeature arrays: three features presented at three separate locations or three features bound at one location. While presenting multiple features--regardless of whether they are at discrete locations or bound within a single object--resulted in greater CDA amplitude relative to a solitary feature, there was a dissociation in the distribution of activity between the two multifeature conditions, such that the CDA at site P1/P2 was sensitive to the number of discrete objects, while activity at P7/P8 was most enhanced when multiple features were bound in one object. The findings demonstrate the inhomogeneity of the CDA and suggest this electrophysiological marker may reflect both discrete object individuation/separation and flexible feature-feature binding in VSTM.

  15. Accelerating solving the dynamic multi-objective nework design problem using response surface methods

    NARCIS (Netherlands)

    Wismans, Luc J.J.; Berkum, van Eric C.; Bliemer, Michiel C.J.

    2011-01-01

    Multi objective optimization of externalities of traffic solving a network design problem in which Dynamic Traffic Management measures are used, is time consuming while heuristics are needed and solving the lower level requires solving the dynamic user equilibrium problem. Use of response surface me

  16. Stochastic estimation of dynamically changing object orientation parameters using satellite measurements

    OpenAIRE

    Lukasevich, V. I.; Kramarov, S. O.; Sokolov, Sergey V.

    2015-01-01

    It is solved a problem of a posteriori estimation of dynamically modified parameters of angular movement of the object by satellite measurements. There are shown advantages of application of the methods of stochastic non-linear dynamic filtration before single-stage measurements. It is represented an example, showing efficiency of proposed approach.

  17. Real-time detection of moving objects in a dynamic scene from moving robotic vehicles

    Science.gov (United States)

    Ansar, A.; Talukder, S.; Goldberg, L.; Matthies, A.

    2003-01-01

    Dynamic scene perception is currently limited to detection of moving objects from a static platform or scenes with flat backgrounds. We discuss novel methods to segment moving objects in the motion field formed by a moving camera/robotic platform in real time.

  18. Acceleration of solving the dynamic multi-objective network design problem using response surface methods

    NARCIS (Netherlands)

    Wismans, L.J.J.; Berkum, van E.C.; Bliemer, M.C.J.

    2014-01-01

    Optimization of externalities and accessibility using dynamic traffic management measures on a strategic level is a specific example of solving a multi-objective network design problem. Solving this optimization problem is time consuming, because heuristics like evolutionary multi objective algorith

  19. Organizational and Spatial Dynamics of Attentional Focusing in Hierarchically Structured Objects

    Science.gov (United States)

    Yeari, Menahem; Goldsmith, Morris

    2011-01-01

    Is the focusing of visual attention object-based, space-based, both, or neither? Attentional focusing latencies in hierarchically structured compound-letter objects were examined, orthogonally manipulating global size (larger vs. smaller) and organizational complexity (two-level structure vs. three-level structure). In a dynamic focusing task,…

  20. The role of boundary objects in the facilitation of dynamic knowledge transfer

    DEFF Research Database (Denmark)

    Sajadirad, Solmaz; Wæhrens, Brian Vejrum; Lassen, Astrid Heidemann

    2015-01-01

    the boundary object as a static knowledge transfer mechanism. This paper explores the dynamic properties of the boundary object as a means to facilitate a continuous learning process. For this purpose we explore the literature and investigate three pilot cases from Danish industry....

  1. Real-time detection of moving objects in a dynamic scene from moving robotic vehicles

    Science.gov (United States)

    Ansar, A.; Talukder, S.; Goldberg, L.; Matthies, A.

    2003-01-01

    Dynamic scene perception is currently limited to detection of moving objects from a static platform or scenes with flat backgrounds. We discuss novel methods to segment moving objects in the motion field formed by a moving camera/robotic platform in real time.

  2. WavePacket: A Matlab package for numerical quantum dynamics. I: Closed quantum systems and discrete variable representations

    Science.gov (United States)

    Schmidt, Burkhard; Lorenz, Ulf

    2017-04-01

    WavePacket is an open-source program package for the numerical simulation of quantum-mechanical dynamics. It can be used to solve time-independent or time-dependent linear Schrödinger and Liouville-von Neumann-equations in one or more dimensions. Also coupled equations can be treated, which allows to simulate molecular quantum dynamics beyond the Born-Oppenheimer approximation. Optionally accounting for the interaction with external electric fields within the semiclassical dipole approximation, WavePacket can be used to simulate experiments involving tailored light pulses in photo-induced physics or chemistry. The graphical capabilities allow visualization of quantum dynamics 'on the fly', including Wigner phase space representations. Being easy to use and highly versatile, WavePacket is well suited for the teaching of quantum mechanics as well as for research projects in atomic, molecular and optical physics or in physical or theoretical chemistry. The present Part I deals with the description of closed quantum systems in terms of Schrödinger equations. The emphasis is on discrete variable representations for spatial discretization as well as various techniques for temporal discretization. The upcoming Part II will focus on open quantum systems and dimension reduction; it also describes the codes for optimal control of quantum dynamics. The present work introduces the MATLAB version of WavePacket 5.2.1 which is hosted at the Sourceforge platform, where extensive Wiki-documentation as well as worked-out demonstration examples can be found.

  3. Intuition in the Context of Object Perception: Intuitive Gestalt Judgments Rest on the Unconscious Activation of Semantic Representations

    Science.gov (United States)

    Bolte, Annette; Goschke, Thomas

    2008-01-01

    Intuition denotes the ability to judge stimulus properties on the basis of information that is activated in memory, but not consciously retrieved. In three experiments we show that participants discriminated better than chance fragmented line drawings depicting meaningful objects (coherent fragments) from fragments consisting of randomly displaced…

  4. Ventral-stream-like shape representation : from pixel intensity values to trainable object-selective COSFIRE models

    NARCIS (Netherlands)

    Azzopardi, George; Petkov, Nicolai

    2014-01-01

    The remarkable abilities of the primate visual system have inspired the construction of computational models of some visual neurons. We propose a trainable hierarchical object recognition model, which we call S-COSFIRE (S stands for Shape and COSFIRE stands for Combination Of Shifted Filter REsponse

  5. Ventral-stream-like shape representation: from pixel intensity values to trainable object-selective COSFIRE models

    NARCIS (Netherlands)

    Azzopardi, G.; Petkov, N.

    2014-01-01

    The remarkable abilities of the primate visual system have inspired the construction of computational models of some visual neurons. We propose a trainable hierarchical object recognition model, which we call S-COSFIRE (S stands for Shape and COSFIRE stands for Combination Of Shifted FIlter REsponse

  6. Infants' Evolving Representations of Object Motion during Occlusion: A Longitudinal Study of 6- to 12-Month-Old Infants

    Science.gov (United States)

    Gredeback, Gustaf; von Hofsten, Claes

    2004-01-01

    Infants' ability to track temporarily occluded objects that moved on circular trajectories was investigated in 20 infants using a longitudinal design. They were first seen at 6 months and then every 2nd month until the end of their 1st year. Infants were presented with occlusion events covering 20% of the target's trajectory (effective occlusion…

  7. 空间对象的几何表示%Representation of Geometry of Spatial Objects

    Institute of Scientific and Technical Information of China (English)

    刘亚彬; 刘大有; 王飞

    2003-01-01

    Spatial reasoning is a hot spot of artificial intelligence areas, and diffusely applied in areas such as geo-graphical information systems, robotic, high level vision, apprehends of natural languages, engineering design, andcommonsense reasoning about physical situations. This paper summarizes and discusses the represent ation of geometryof spatial objects roundly.

  8. Intuition in the Context of Object Perception: Intuitive Gestalt Judgments Rest on the Unconscious Activation of Semantic Representations

    Science.gov (United States)

    Bolte, Annette; Goschke, Thomas

    2008-01-01

    Intuition denotes the ability to judge stimulus properties on the basis of information that is activated in memory, but not consciously retrieved. In three experiments we show that participants discriminated better than chance fragmented line drawings depicting meaningful objects (coherent fragments) from fragments consisting of randomly displaced…

  9. A dynamic code for economic object valuation in prefrontal cortex neurons.

    Science.gov (United States)

    Tsutsui, Ken-Ichiro; Grabenhorst, Fabian; Kobayashi, Shunsuke; Schultz, Wolfram

    2016-09-13

    Neuronal reward valuations provide the physiological basis for economic behaviour. Yet, how such valuations are converted to economic decisions remains unclear. Here we show that the dorsolateral prefrontal cortex (DLPFC) implements a flexible value code based on object-specific valuations by single neurons. As monkeys perform a reward-based foraging task, individual DLPFC neurons signal the value of specific choice objects derived from recent experience. These neuronal object values satisfy principles of competitive choice mechanisms, track performance fluctuations and follow predictions of a classical behavioural model (Herrnstein's matching law). Individual neurons dynamically encode both, the updating of object values from recently experienced rewards, and their subsequent conversion to object choices during decision-making. Decoding from unselected populations enables a read-out of motivational and decision variables not emphasized by individual neurons. These findings suggest a dynamic single-neuron and population value code in DLPFC that advances from reward experiences to economic object values and future choices.

  10. Representation of spatial- and object-specific behavioral goals in the dorsal globus pallidus of monkeys during reaching movement.

    Science.gov (United States)

    Saga, Yosuke; Hashimoto, Masashi; Tremblay, Léon; Tanji, Jun; Hoshi, Eiji

    2013-10-09

    The dorsal aspect of the globus pallidus (GP) communicates with the prefrontal cortex and higher-order motor areas, indicating that it plays a role in goal-directed behavior. We examined the involvement of dorsal GP neurons in behavioral goal monitoring and maintenance, essential components of executive function. We trained two macaque monkeys to choose a reach target based on relative target position in a spatial goal task or a target shape in an object-goal task. The monkeys were trained to continue to choose a certain behavioral goal when reward volume was constant and to switch the goals when the volume began to decrease. Because the judgment for the next goal was made in the absence of visual signals, the monkeys were required to monitor and maintain the chosen goals during the reaching movement. We obtained three major findings. (1) GP neurons reflected more of the relative spatial position than the shape of the reaching target during the spatial goal task. During the object-goal task, the shape of the reaching object was represented more than the relative position. (2) The selectivity of individual neurons for the relative position was enhanced during the spatial goal task, whereas the object-shape selectivity was enhanced during the object-goal task. (3) When the monkeys switched the goals, the selectivity for either the position or shape also switched. Together, these findings suggest that the dorsal GP is involved in behavioral goal monitoring and maintenance during execution of goal-oriented actions, presumably in collaboration with the prefrontal cortex.

  11. Quantum and semiclassical phase-space dynamics of a wave packet in strong fields using initial-value representations

    CERN Document Server

    Zagoya, C; Ronto, M; Shalashilin, D V; Faria, C Figueira de Morisson

    2014-01-01

    We assess the suitability of quantum and semiclassical initial value representations, exemplified by the coupled coherent states (CCS) method and the Herman Kluk (HK) propagator, respectively, for modeling the dynamics of an electronic wave packet in a strong laser field, if this wave packet is initially bound. Using Wigner quasiprobability distributions and ensembles of classical trajectories, we identify signatures of over-the-barrier and tunnel ionization in phase space for static and time-dependent fields and the relevant sets of phase-space trajectories in order to model such features. Overall, we find good agreement with the full solution of the time-dependent Schr\\"odinger equation (TDSE) for Wigner distributions constructed with both initial-value representations. Our results indicate that the HK propagator does not fully account for tunneling and over-the-barrier reflections. However, it is able to partly reproduce features associated with the wave packet crossing classically forbidden regions, altho...

  12. Validation of Atmospheric Dynamics (VADY) - representation of circulation types/dynamical modes in the decadal-prediction model system of MPI-ESM

    Science.gov (United States)

    Lang, Benjamin; Jacobeit, Jucundus; Beck, Christoph; Philipp, Andreas

    2016-04-01

    The climate research program "Medium-range Climate Predictions" (MiKlip), funded by the Federal Ministry of Education and Research in Germany (BMBF), has the aim to improve a climate model system (MPI-ESM) in such a way that it can provide reliable decadal predictions of climate, including extreme weather events. A substantial part of the development process is a comprehensive model validation. Within MiKlip, it includes comparisons of model simulations and observations in order to allow statements about the performance of the model and to give particular recommendations for the further development of the model. The research project "Validation of Atmospheric Dynamics" (VADY), conducted by the cooperation partners "Institute of Geography at the University of Augsburg" (IGUA) and the "German Aerospace Centre" (DLR), contributes to model validation within MiKlip with a special focus on atmospheric waves (DLR) and circulation dynamics (IGUA). Within the framework of VADY, DLR validates the representation of atmospheric waves on different levels and scales based on suitable activity indices (e.g. the so-called large-scale dynamical activity index (LDAI), which is a measure for the activity of planetary waves). The focus of IGUA is on the model validation with respect to the representation of atmospheric circulation types, dynamical modes and the teleconnectivity of the atmospheric circulation. The present contribution provides results of the model validation concerning circulation types/dynamical modes. Results are shown for both the frequency of occurrence and internal characteristics (e. g. persistence or intensity), and for different classification methods (e. g. based on PCA or clustering techniques). The representation of circulation types/dynamical modes will be compared for different generations of the MPI-ESM decadal-prediction model (baseline0, baseline1, prototype) in order to clarify both advances and limitations in the development of the model. Furthermore

  13. Neural networks for action representation underlying automatic mimicry: A functional magnetic-resonance imaging and dynamic causal modeling study

    Directory of Open Access Journals (Sweden)

    Akihiro T Sasaki

    2012-08-01

    Full Text Available Automatic mimicry is based on the tight linkage between motor and perception action representations in which internal models play a key role. Based on the anatomical connection, we hypothesized that the direct effective connectivity from the posterior superior temporal sulcus (pSTS to the ventral premotor area (PMv formed an inverse internal model, converting visual representation into a motor plan, and that reverse connectivity formed a forward internal model, converting the motor plan into a sensory outcome of action. To test this hypothesis, we employed dynamic causal-modeling analysis with functional magnetic-resonance imaging. Twenty-four normal participants underwent a change-detection task involving two visually-presented balls that were either manually rotated by the investigator’s right hand (‘Hand’ or automatically rotated. The effective connectivity from the pSTS to the PMv was enhanced by hand observation and suppressed by execution, corresponding to the inverse model. Opposite effects were observed from the PMv to the pSTS, suggesting the forward model. Additionally, both execution and hand observation commonly enhanced the effective connectivity from the pSTS to the inferior parietal lobule (IPL, the IPL to the primary sensorimotor cortex (S/M1, the PMv to the IPL, and the PMv to the S/M1. Representation of the hand action therefore was implemented in the motor system including the S/M1. During hand observation, effective connectivity toward the pSTS was suppressed whereas that toward the PMv and S/M1 was enhanced. Thus the action-representation network acted as a dynamic feedback-control system during action observation.

  14. Developing a 3-D Digital Heritage Ecosystem: from object to representation and the role of a virtual museum in the 21st century

    Directory of Open Access Journals (Sweden)

    Fred Limp

    2011-07-01

    Full Text Available This article addresses the application of high-precision 3-D recording methods to heritage materials (portable objects, the technical processes involved, the various digital products and the role of 3-D recording in larger questions of scholarship and public interpretation. It argues that the acquisition and creation of digital representations of heritage must be part of a comprehensive research infrastructure (a digital ecosystem that focuses on all of the elements involved, including (a recording methods and metadata, (b digital object discovery and access, (c citation of digital objects, (d analysis and study, (e digital object reuse and repurposing, and (f the critical role of a national/international digital archive. The article illustrates these elements and their relationships using two case studies that involve similar approaches to the high-precision 3-D digital recording of portable archaeological objects, from a number of late pre-Columbian villages and towns in the mid-central US (c. 1400 CE and from the Egyptian site of Amarna, the Egyptian Pharaoh Akhenaten's capital (c. 1300 BCE.

  15. Dynamic Clustering in Object-Oriented Databases: An Advocacy for Simplicity

    CERN Document Server

    Darmont, Jérôme; Régnier, Stéphane; Gruenwald, Le; Schneider, Michel

    2007-01-01

    We present in this paper three dynamic clustering techniques for Object-Oriented Databases (OODBs). The first two, Dynamic, Statistical & Tunable Clustering (DSTC) and StatClust, exploit both comprehensive usage statistics and the inter-object reference graph. They are quite elaborate. However, they are also complex to implement and induce a high overhead. The third clustering technique, called Detection & Reclustering of Objects (DRO), is based on the same principles, but is much simpler to implement. These three clustering algorithm have been implemented in the Texas persistent object store and compared in terms of clustering efficiency (i.e., overall performance increase) and overhead using the Object Clustering Benchmark (OCB). The results obtained showed that DRO induced a lighter overhead while still achieving better overall performance.

  16. A Dynamic Feature-Based Method for Hybrid Blurred/Multiple Object Detection in Manufacturing Processes

    Directory of Open Access Journals (Sweden)

    Tsun-Kuo Lin

    2016-01-01

    Full Text Available Vision-based inspection has been applied for quality control and product sorting in manufacturing processes. Blurred or multiple objects are common causes of poor performance in conventional vision-based inspection systems. Detecting hybrid blurred/multiple objects has long been a challenge in manufacturing. For example, single-feature-based algorithms might fail to exactly extract features when concurrently detecting hybrid blurred/multiple objects. Therefore, to resolve this problem, this study proposes a novel vision-based inspection algorithm that entails selecting a dynamic feature-based method on the basis of a multiclassifier of support vector machines (SVMs for inspecting hybrid blurred/multiple object images. The proposed algorithm dynamically selects suitable inspection schemes for classifying the hybrid images. The inspection schemes include discrete wavelet transform, spherical wavelet transform, moment invariants, and edge-feature-descriptor-based classification methods. The classification methods for single and multiple objects are adaptive region growing- (ARG- based and local adaptive region growing- (LARG- based learning approaches, respectively. The experimental results demonstrate that the proposed algorithm can dynamically select suitable inspection schemes by applying a selection algorithm, which uses SVMs for classifying hybrid blurred/multiple object samples. Moreover, the method applies suitable feature-based schemes on the basis of the classification results for employing the ARG/LARG-based method to inspect the hybrid objects. The method improves conventional methods for inspecting hybrid blurred/multiple objects and achieves high recognition rates for that in manufacturing processes.

  17. Testing Object-Oriented Programs using Dynamic Aspects and Non-Determinism

    DEFF Research Database (Denmark)

    Achenbach, Michael; Ostermann, Klaus

    2010-01-01

    without parameterization or generation of tests. It also eases modelling naturally non-deterministic program features like IO or multi-threading in integration tests. Dynamic AOP facilitates powerful design adaptations without exposing test features, keeping the scope of these adaptations local to each...... test. We also combine non-determinism and dynamic aspects in a new approach to testing multi-threaded programs using co-routines.......The implementation of unit tests with mock objects and stubs often involves substantial manual work. Stubbed methods return simple default values, therefore variations of these values require separate test cases. The integration of mock objects often requires more infrastructure code and design...

  18. A dynamic object-oriented architecture approach to ecosystem modeling and simulation.

    Energy Technology Data Exchange (ETDEWEB)

    Dolph, J. E.; Majerus, K. A.; Sydelko, P. J.; Taxon, T. N.

    1999-04-09

    Modeling and simulation in support of adaptive ecosystem management can be better accomplished through a dynamic, integrated, and flexible approach that incorporates scientific and technological components into a comprehensive ecosystem-modeling framework. The Integrated Dynamic Landscape Analysis and Modeling System (IDLAMS) integrates ecological models and decision support techniques, through a geographic information system (GIS)-based framework. The Strategic Environmental Research and Development Program (SERDP) sponsored the development of IDLAMS. Initially built upon a GIS framework, IDLAMS is migrating to an object-oriented (OO) architectural framework. An object-oriented architecture is more flexible and modular. It allows disparate applications and dynamic models to be integrated in a manner that minimizes (or eliminates) the need to rework or recreate the system as new models are added to the suite. In addition, an object-oriented design makes it easier to provide run-time feedback among models, thereby making it a more dynamic tool for exploring and providing insight into the interactions among ecosystem processes. Finally, an object-oriented design encourages the reuse of existing technology because OO-IDLAMS is able to integrate disparate models, databases, or applications executed in their native languages. Reuse is also accomplished through a structured approach to building a consistent and reusable object library. This reusability can substantially reduce the time and effort needed to develop future integrated ecosystem simulations.

  19. Long-Term Dynamics and the Orbital Inclinations of the Classical Kuiper Belt Objects

    CERN Document Server

    Kuchner, M J; Holman, M; Kuchner, Marc J.; Brown, Michael E.; Holman, Matthew

    2002-01-01

    We numerically integrated the orbits of 1458 particles in the region of the classical Kuiper Belt (41 AU < a < 47 AU) to explore the role of dynamical instabilities in sculpting the inclination distribution of the classical Kuiper Belt Objects (KBOs). We find that the selective removal of low-inclination objects by overlapping secular resonances (nu_17 and nu_18) acts to raise the mean inclination of the surviving population of particles over 4 billion years of interactions with Jupiter, Saturn, Uranus and Neptune, though these long-term dynamical effects do not themselves appear to explain the discovery of KBOs with inclinations near 30 degrees. Our integrations also imply that after 3 billion years of interaction with the massive planets, high inclination KBOs more efficiently supply Neptune-encountering objects, the likely progenitors of short-period comets, Centaurs, and scattered KBOs. The secular resonances at low inclinations may indirectly cause this effect by weeding out objects unprotected by ...

  20. Recoding between two types of STM representation revealed by the dynamics of memory search.

    Science.gov (United States)

    Leszczyński, Marcin; Myers, Nicholas E; Akyürek, Elkan G; Schubö, Anna

    2012-03-01

    Visual STM (VSTM) is thought to be related to visual attention in several ways. Attention controls access to VSTM during memory encoding and plays a role in the maintenance of stored information by strengthening memorized content. We investigated the involvement of visual attention in recall from VSTM. In two experiments, we measured electrophysiological markers of attention in a memory search task with varying intervals between VSTM encoding and recall, and so we were able to track recoding of representations in memory. Results confirmed the involvement of attention in VSTM recall. However, the amplitude of the N2pc and N3rs components, which mark orienting of attention and search within VSTM, decreased as a function of delay. Conversely, the amplitude of the P3 and sustained posterior contralateral negativity components increased as a function of delay, effectively the opposite of the N2pc and N3rs modulations. These effects were only observed when verbal memory was not taxed. Thus, the results suggested that gradual recoding from visuospatial orienting of attention into verbal recall mechanisms takes place from short to long retention intervals. Interestingly, recall at longer delays was faster than at short delays, indicating that verbal representation is coupled with faster responses. These results extend the orienting-of-attention hypothesis by including an account of representational recoding during short-term consolidation and its consequences for recall from VSTM.

  1. Abnormal dynamics of activation of object use information in apraxia: evidence from eyetracking.

    Science.gov (United States)

    Lee, Chia-Iin; Mirman, Daniel; Buxbaum, Laurel J

    2014-07-01

    Action representations associated with object use may be incidentally activated during visual object processing, and the time course of such activations may be influenced by lexical-semantic context (e.g., Lee, Middleton, Mirman, Kalénine, & Buxbaum (2012). Journal of Experimental Psychology: Human Perception and Performance, 39(1), 257-270). In this study we used the "visual world" eye-tracking paradigm to examine whether a deficit in producing skilled object-use actions (apraxia) is associated with abnormalities in incidental activation of action information, and assessed the neuroanatomical substrates of any such deficits. Twenty left hemisphere stroke patients, ten of whom were apraxic, performed a task requiring identification of a named object in a visual display containing manipulation-related and unrelated distractor objects. Manipulation relationships among objects were not relevant to the identification task. Objects were cued with neutral ("S/he saw the…."), or action-relevant ("S/he used the….") sentences. Non-apraxic participants looked at use-related non-target objects significantly more than at unrelated non-target objects when cued both by neutral and action-relevant sentences, indicating that action information is incidentally activated. In contrast, apraxic participants showed delayed activation of manipulation-based action information during object identification when cued by neutral sentences. The magnitude of delayed activation in the neutral sentence condition was reliably predicted by lower scores on a test of gesture production to viewed objects, as well as by lesion loci in the inferior parietal and posterior temporal lobes. However, when cued by a sentence containing an action verb, apraxic participants showed fixation patterns that were statistically indistinguishable from non-apraxic controls. In support of grounded theories of cognition, these results suggest that apraxia and temporal-parietal lesions may be associated with

  2. Hologram representation of design data in an expert system knowledge base

    Science.gov (United States)

    Shiva, S. G.; Klon, Peter F.

    1988-01-01

    A novel representational scheme for design object descriptions is presented. An abstract notion of modules and signals is developed as a conceptual foundation for the scheme. This abstraction relates the objects to the meaning of system descriptions. Anchored on this abstraction, a representational model which incorporates dynamic semantics for these objects is presented. This representational model is called a hologram scheme since it represents dual level information, namely, structural and semantic. The benefits of this scheme are presented.

  3. On model checking the dynamics of object-based software : a foundational approach

    NARCIS (Netherlands)

    Distefano, Dino Salvo

    2003-01-01

    This dissertation is concerned with software verication, in particular automated techniques to assess the correct functioning of object-based programs. We focus on the dynamic aspects of these programs and consider model-checking based verication techniques. The major obstacle to the design of model

  4. Learning Mathematics by Designing, Programming, and Investigating with Interactive, Dynamic Computer-Based Objects

    Science.gov (United States)

    Marshall, Neil; Buteau, Chantal

    2014-01-01

    As part of their undergraduate mathematics curriculum, students at Brock University learn to create and use computer-based tools with dynamic, visual interfaces, called Exploratory Objects, developed for the purpose of conducting pure or applied mathematical investigations. A student's Development Process Model of creating and using an Exploratory…

  5. C++ Toolbox for Object-Oriented Modeling and Dynamic Simulation of Physical Systems

    DEFF Research Database (Denmark)

    Wagner, Falko Jens; Poulsen, Mikael Zebbelin

    1999-01-01

    This paper presents the efforts made in an ongoing project that exploits the advantages of using object-oriented methodologies for describing and simulating dynamical systems. The background for this work is a search for new and better ways to simulate physical systems....

  6. Safety Margins in Older Adults Increase with Improved Control of a Dynamic Object

    Directory of Open Access Journals (Sweden)

    Christopher James Hasson

    2014-07-01

    Full Text Available Older adults face decreasing motor capabilities due to pervasive neuromuscular degradations. As a consequence errors in movement control increase. Thus, older individuals should maintain larger safety margins than younger adults. While this has been shown for object manipulation tasks, several reports on whole-body activities, such as posture and locomotion, however demonstrate age-related reductions in safety margins. This is despite increased costs for control errors, such as a fall. We posit that this paradox could be explained by the dynamic challenge presented by the body or an external object, and that age-related reductions in safety margins are in part due to a decreased ability to control dynamics. To test this conjecture we used a virtual ball-in-cup task that had challenging dynamics, yet afforded an explicit rendering of the physics and safety margin. The hypotheses were: 1 When manipulating an object with challenging dynamics, older adults have smaller safety margins than younger adults. 2 Older adults increase their safety margins with practice. Nine young and 10 healthy older adults practiced moving the virtual ball-in-cup to a target location in exactly two seconds. The accuracy and precision of the timing error quantified skill and the ball energy relative to an escape threshold quantified the safety margin. Compared to the young adults, older adults had increased timing errors, greater variability, and decreased safety margins. With practice, both young and older adults improved their ability to control the object with decreased timing errors and variability, and increased their safety margins. These results suggest that safety margins are related to the ability to control dynamics, and may explain why in tasks with simple dynamics older adults use adequate safety margins, but in more complex tasks, safety margins may be inadequate. Further, the results indicate that task-specific training may improve safety margins in older

  7. Design Dynamic Coupling Measurement of Distributed Object Oriented Software Using Trace Events

    Directory of Open Access Journals (Sweden)

    S. Babu

    2011-01-01

    Full Text Available Problem statement: A common way to define and measure coupling is through structural properties and static code analysis. However, because of polymorphism, dynamic binding and the common presence of unused code in commercial software, the resulting coupling measures are imprecise as they do not perfectly reflect the actual coupling taking place among classes at run-time. For example, when using static analysis to measure coupling, it is difficult and sometimes impossible to determine what actual methods can be invoked from a client class if those methods are overridden in the subclasses of the server classes. Approach: Coupling measurement has traditionally been performed using static code analysis, because most of the existing work was done on non-object oriented code and because dynamic code analysis is more expensive and complex to perform. We refer to this type of coupling as dynamic coupling. In this study we propose a dynamic and efficient measurement technique over object oriented software. Result: We propose a hybrid model to measure the dynamic coupling present in distributed object oriented software. The proposed method has three steps; they are instrumentation process, post process and coupling measurement. First, the instrumentation process is performed. In this process, to trace method calls, a modified instrumented JVM has been used. During this process, three trace files, .prf, .clp and .svp are created. In the second step, the information present in these files, are merged. At the end of this step, the merged detailed trace of each Jvms contains pointers to the merged trace files of the other JVM’s such that the path of each remote call from the client to the server can be uniquely identified. Conclusion: Finally, the coupling metrics are measured dynamically. The proposed system was implemented in JAVA.The implementation results show that the proposed system effectively measures the dynamic coupling.

  8. Dynamics and Stability of Blind Grasping of a 3-Dimensional Object under Non-holonomic Constraints

    Institute of Scientific and Technical Information of China (English)

    Suguru Arimoto; Morio Yoshida; Ji-Hun Bae

    2006-01-01

    A mathematical model expressing the motion of a pair of multi-DOF robot fingers with hemi-spherical ends,grasping a 3-D rigid object with parallel flat surfaces, is derived, together with non-holonomic constraints. By referring to the fact that humans grasp an object in the form of precision prehension, dynamically and stably by opposable forces, between the thumb and another finger (index or middle finger), a simple control signal constructed from finger-thumb opposition is proposed, and shown to realize stable grasping in a dynamic sense without using object information or external sensing (this is called "blind grasp" in this paper). The stability of grasping with force/torque balance under non-holonomic constraints is analyzed on the basis of a new concept named "stability on a manifold". Preliminary simulation results are shown to verify the validity of the theoretical results.

  9. Object Tracking System Using Approximate Median Filter, Kalman Filter and Dynamic Template Matching

    Directory of Open Access Journals (Sweden)

    G. Mallikarjuna Rao

    2014-04-01

    Full Text Available In this work, we dealt with the tracking of single object in a sequence of frames either from a live camera or a previously saved video. A moving object is detected frame-by-frame with high accuracy and efficiency using Median approximation technique. As soon as the object has been detected, the same is tracked by kalman filter estimation technique along with a more accurate Template Matching algorithm. The templates are dynamically generated for this purpose. This guarantees any change in object pose which does not be hindered from tracking procedure. The system is capable of handling entry and exit of an object. Such a tracking scheme is cost effective and it can be used as an automated video conferencing system and also has application as a surveillance tool. Several trials of the tracking show that the approach is correct and extremely fast, and it's a more robust performance throughout the experiments.

  10. Editorial : islands : objects of representation

    OpenAIRE

    Baldacchino, Godfrey

    2005-01-01

    In this article, Baldacchino tries to define what is an island and what makes an island. Insularity is a diverse experience ranging from the remoteness of Easter Island in the Pacific to the more international and globalized islands of the Western world.

  11. Object-oriented Urban Dynamic Monitoring——A Case Study of Haidian District of Beijing

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    It is crucial to conduct the land use/cover research to obtain the global change information. Urban area is one of the most sensitive areas in land use/cover change. Therefore land use/cover change in urban areas is very important in global change. It is vital to incorporate the information of urban land use/cover change into the process of decision-making about urban area development. In this paper, a new urban change detection approach, urban dynamic monitoring based on objects, is introduced. This approach includes four steps: 1) producing multi-scale objects from multi-temporal remotely sensed images with spectrum, texture and context information; 2) extracting possible changed objects adopting object-oriented classification; 3) obtaining shared objects as the basic units for urban change detection;4) determining the threshold to segment the changed objects from the possible changed objects using Otsu method. In this paper, the object-based approach was applied to detecting the urban expansion in Haidian District, Beijing, China with two Landsat Thematic Mapper (TM) data in 1997 and 2004. The results indicated that the overall accuracy was about 84.83%, and Kappa about 0.785. Compared with other conventional approaches, the object-based approach was advantageous in reducing the error accumulation of image classification of each datum and in independence to the radiometric correction and image registration accuracy.

  12. Representation of dynamic interaural phase difference in auditory cortex of awake rhesus macaques.

    Science.gov (United States)

    Scott, Brian H; Malone, Brian J; Semple, Malcolm N

    2009-04-01

    Neurons in auditory cortex of awake primates are selective for the spatial location of a sound source, yet the neural representation of the binaural cues that underlie this tuning remains undefined. We examined this representation in 283 single neurons across the low-frequency auditory core in alert macaques, trained to discriminate binaural cues for sound azimuth. In response to binaural beat stimuli, which mimic acoustic motion by modulating the relative phase of a tone at the two ears, these neurons robustly modulate their discharge rate in response to this directional cue. In accordance with prior studies, the preferred interaural phase difference (IPD) of these neurons typically corresponds to azimuthal locations contralateral to the recorded hemisphere. Whereas binaural beats evoke only transient discharges in anesthetized cortex, neurons in awake cortex respond throughout the IPD cycle. In this regard, responses are consistent with observations at earlier stations of the auditory pathway. Discharge rate is a band-pass function of the frequency of IPD modulation in most neurons (73%), but both discharge rate and temporal synchrony are independent of the direction of phase modulation. When subjected to a receiver operator characteristic analysis, the responses of individual neurons are insufficient to account for the perceptual acuity of these macaques in an IPD discrimination task, suggesting the need for neural pooling at the cortical level.

  13. Varied representation of the West Pacific pattern in multiple dynamical seasonal predictions of APCC-MME

    Science.gov (United States)

    Lee, Yun-Young

    2017-04-01

    West Pacific (WP) teleconnection pattern is one of the well-known primary modes of boreal winter low-frequency variability (LFV) resolved in 500 hPa geopotential height and its phase and amplitude strongly influence regional weather conditions including temperature and rainfall extremes [Baxter and Nigam, 2015; Hsu and Wallace, 1985; Linkin and Nigam, 2008; Mo and Livezey, 1986; Thompson and Wallace, 1998; Wallace and Gutzler, 1981]. This study primary aims to evaluate individual 11 GCMs seasonal hindcasts employed as members of multi-model ensemble (MME) produced in APEC Climate Center (APCC) in representing WP. For the extensive and comprehensive evaluation, this study applied seven verification metrics in three scopes: (a) temporal representation of observed indices, (b) spatial mode separation in the Northern Hemisphere (NH), and (c) regional mode isolated in the preset longitudinal domain. Verification results display quite large inter-model spread. Some models mimic observed index variability while others display large bias of index variability compared to climatology. Basic north-south dipole pattern is mostly well reproduced in both rotated and unrotated loading modes. However, each individual seasonal forecast model exhibits slightly different behavior (e.g. amplification/weakening, zonal and meridional shift, downstream extension and so forth) in representing spatial structure of WP. When taking all 7 metrics into account, one Europe (CMCC) model, one Oceania (POAMA) model and two North America (NASA and NCEP) models are classified as relatively good performers while PNU is classified as a matchless poor performer out of 11. Least WP representing skill of PNU is sort of consistent with the largest bias of NH total variability. This study further tries to examine winter mean biases of individual models and figure out how mean bias is linked to WP representation in model world. Model bias of winter climatology is investigated focusing on six large scale

  14. Nonlinear dynamic model for visual object tracking on Grassmann manifolds with partial occlusion handling.

    Science.gov (United States)

    Khan, Zulfiqar Hasan; Gu, Irene Yu-Hua

    2013-12-01

    This paper proposes a novel Bayesian online learning and tracking scheme for video objects on Grassmann manifolds. Although manifold visual object tracking is promising, large and fast nonplanar (or out-of-plane) pose changes and long-term partial occlusions of deformable objects in video remain a challenge that limits the tracking performance. The proposed method tackles these problems with the main novelties on: 1) online estimation of object appearances on Grassmann manifolds; 2) optimal criterion-based occlusion handling for online updating of object appearances; 3) a nonlinear dynamic model for both the appearance basis matrix and its velocity; and 4) Bayesian formulations, separately for the tracking process and the online learning process, that are realized by employing two particle filters: one is on the manifold for generating appearance particles and another on the linear space for generating affine box particles. Tracking and online updating are performed in an alternating fashion to mitigate the tracking drift. Experiments using the proposed tracker on videos captured by a single dynamic/static camera have shown robust tracking performance, particularly for scenarios when target objects contain significant nonplanar pose changes and long-term partial occlusions. Comparisons with eight existing state-of-the-art/most relevant manifold/nonmanifold trackers with evaluations have provided further support to the proposed scheme.

  15. DYNAMIC LAYOUT ADJUSTMENT AND NAVIGATION FOR ENTERPRISE GIS BASED ON OBJECT MARK RECOGNITION

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In this paper a new method is developed to make a dynamic layout adjustment and navigation for enterprise Geographic Information System(GIS) based on object mark recognition. The extraction of object mark images is based on some morphological structural patterns, which are described by morphological structural points, contour property, and other geometrical data in a binary image of enterprise geographic information map. Some pre-processing methods, contour smooth following, linearization and extraction patterns of structural points, are introduced. If any special object is selected to make a decision in a GIS map, the all information around it will be obtained. That is, we need to investigate similar object enterprises around selected region to analyse whether it is necessary for establishing the object enterprise at that place. To further navigate GIS map, we need to move from one region to another. Each time a region is formed and displayed based on the user′ s focus. If a focus point of a map is selected, in terms of extracted object mark image, a dynamic layout and navigation diagram is constructed. When the user changes the focus (i.e. click a node in the navigation mode), a new sub-diagram is formed by dropping old nodes and adding new nodes. The prototype system provides effective interfaces that support GIS image navigation, detailed local image/map viewing, and enterprise information browsing.

  16. The Dynamical Yang-Baxter Relation and the Minimal Representation of the Elliptic Quantum Group

    CERN Document Server

    Fan, H; Shi, K J; Yue, R H; Zhao, S Y; Fan, Heng; Hou, Bo-Yu; Shi, Kang-Jie; Yue, Rui-Hong; Zhao, Shao-You

    2003-01-01

    In this paper, we give the general forms of the minimal $L$ matrix (the elements of the $L$-matrix are $c$ numbers) associated with the Boltzmann weights of the $A_{n-1}^1$ interaction-round-a-face (IRF) model and the minimal representation of the $A_{n-1}$ series elliptic quantum group given by Felder and Varchenko. The explicit dependence of elements of $L$-matrices on spectral parameter $z$ are given. They are of five different forms (A(1-4) and B). The algebra for the coefficients (which do not depend on $z$) are given. The algebra of form A is proved to be trivial, while that of form B obey Yang-Baxter equation (YBE). We also give the PBW base and the centers for the algebra of form B.

  17. Multi-objective dynamic optimization model for China's road transport energy technology switching

    Institute of Scientific and Technical Information of China (English)

    Dan GAO; Zheng LI; Feng FU; Linwei MA

    2009-01-01

    Deducting the future switching of the road transport energy technology is one of the key preconditions for relative technology development planning. However,one of the difficulties is to address the issue of multi-objective and conflicting constrains, e.g., minimizing the climate mitigation or minimizing economic cost. In this paper, a dynamic optimization model was established, which can be used to analyze the road transport energy technology switching under multi-objective constrains.Through one case study, a series of solutions could be derived to provide decision-makers with the flexibility to choose the appropriate solution with respect to the given situation.

  18. Dynamic population artificial bee colony algorithm for multi-objective optimal power flow

    Directory of Open Access Journals (Sweden)

    Man Ding

    2017-03-01

    Full Text Available This paper proposes a novel artificial bee colony algorithm with dynamic population (ABC-DP, which synergizes the idea of extended life-cycle evolving model to balance the exploration and exploitation tradeoff. The proposed ABC-DP is a more bee-colony-realistic model that the bee can reproduce and die dynamically throughout the foraging process and population size varies as the algorithm runs. ABC-DP is then used for solving the optimal power flow (OPF problem in power systems that considers the cost, loss, and emission impacts as the objective functions. The 30-bus IEEE test system is presented to illustrate the application of the proposed algorithm. The simulation results, which are also compared to nondominated sorting genetic algorithm II (NSGAII and multi-objective ABC (MOABC, are presented to illustrate the effectiveness and robustness of the proposed method.

  19. Multi-objective evolutionary optimization of biological pest control with impulsive dynamics in soybean crops.

    Science.gov (United States)

    Cardoso, Rodrigo T N; da Cruz, André R; Wanner, Elizabeth F; Takahashi, Ricardo H C

    2009-08-01

    The biological pest control in agriculture, an environment-friendly practice, maintains the density of pests below an economic injury level by releasing a suitable quantity of their natural enemies. This work proposes a multi-objective numerical solution to biological pest control for soybean crops, considering both the cost of application of the control action and the cost of economic damages. The system model is nonlinear with impulsive control dynamics, in order to cope more effectively with the actual control action to be applied, which should be performed in a finite number of discrete time instants. The dynamic optimization problem is solved using the NSGA-II, a fast and trustworthy multi-objective genetic algorithm. The results suggest a dual pest control policy, in which the relative price of control action versus the associated additional harvest yield determines the usage of either a low control action strategy or a higher one.

  20. Dynamic social representations of the 2009 H1N1 pandemic: Shifting patterns of sense-making and blame.

    Science.gov (United States)

    Mayor, Eric; Eicher, Véronique; Bangerter, Adrian; Gilles, Ingrid; Clémence, Alain; Green, Eva G T

    2013-11-01

    We investigate dynamics of public perceptions of the 2009 H1N1 influenza pandemic to understand changing patterns of sense-making and blame regarding the outbreak of emerging infectious diseases. We draw on social representation theory combined with a dramaturgical perspective to identify changes in how various collectives are depicted over the course of the pandemic, according to three roles: heroes, villains and victims. Quantitative results based on content analysis of three cross-sectional waves of interviews show a shift from mentions of distant collectives (e.g., far-flung countries) at Wave 1 to local collectives (e.g., risk groups) as the pandemic became of more immediate concern (Wave 2) and declined (Wave 3). Semi-automated content analysis of media coverage shows similar results. Thematic analyses of the discourse associated with collectives revealed that many were consistently perceived as heroes, villains and victims.

  1. Concurrent Dynamic Visualizations With Expressive Petri Net Representations to Enrich the Understanding of Biological and Pathological Processes: an Application to Signaling Pathways

    Directory of Open Access Journals (Sweden)

    F. Ramos

    2012-10-01

    Full Text Available Dynamic visualizations and expressive representations are needed in systems biology to handle multiple interactionsoccurring during the biological processes of biopathway representations. Dynamic visualizations allow users an easeof interaction with pathway models. At the same time, representations of biopathways should express how interactionstake place. In spite of the fact that diverse databases provide users with pathways, their information andrepresentation are frequently different from each other and show restricted interactions because of their staticvisualization. An adopted solution is to merge diverse representations to obtain a richer one. However, due to differentformats and the multiple links involved in the pathway representations, the merge results frequently in erroneousmodels and in a tangle web of relations very hard to be manipulated. Instead, this work introduces a concurrentdynamic visualization (CDV of the same pathway, which is retrieved from different sites and then transformed intoPetri net representations to facilitate the understanding of their biological processes by interacting with them. Weapplied this approach to the analysis of the Notch signaling pathway, associated with cervical cancer; we obtained itfrom different sources which we compared and manipulated simultaneously by interacting with the provided CDV untilthe user generated a personalized pathway.

  2. A multi-objective dynamic programming approach to constrained discrete-time optimal control

    Energy Technology Data Exchange (ETDEWEB)

    Driessen, B.J.; Kwok, K.S.

    1997-09-01

    This work presents a multi-objective differential dynamic programming approach to constrained discrete-time optimal control. In the backward sweep of the dynamic programming in the quadratic sub problem, the sub problem input at a stage or time step is solved for in terms of the sub problem state entering that stage so as to minimize the summed immediate and future cost subject to minimizing the summed immediate and future constraint violations, for all such entering states. The method differs from previous dynamic programming methods, which used penalty methods, in that the constraints of the sub problem, which may include terminal constraints and path constraints, are solved exactly if they are solvable; otherwise, their total violation is minimized. Again, the resulting solution of the sub problem is an input history that minimizes the quadratic cost function subject to being a minimizer of the total constraint violation. The expected quadratic convergence of the proposed algorithm is demonstrated on a numerical example.

  3. Multi-objective Optimization For The Dynamic Multi-Pickup and Delivery Problem with Time Windows

    CERN Document Server

    Dridi, Imen Harbaoui; Borne, Pierre; Ksouri, Mekki

    2011-01-01

    The PDPTW is an optimization vehicles routing problem which must meet requests for transport between suppliers and customers satisfying precedence, capacity and time constraints. We present, in this paper, a genetic algorithm for multi-objective optimization of a dynamic multi pickup and delivery problem with time windows (Dynamic m-PDPTW). We propose a brief literature review of the PDPTW, present our approach based on Pareto dominance method and lower bounds, to give a satisfying solution to the Dynamic m-PDPTW minimizing the compromise between total travel cost and total tardiness time. Computational results indicate that the proposed algorithm gives good results with a total tardiness equal to zero with a tolerable cost.

  4. The Dynamic Multi-objective Multi-vehicle Covering Tour Problem

    Science.gov (United States)

    2013-06-01

    Routing Problem VEGA Vector Evaluated Genetic Algorithm VRP Vehicle Routing Problem VRPTW Vehicle routing problem with time windows xiv THE DYNAMIC MULTI...the TSP, CTP and Vehicle Routing Problem ( VRP ). Reviews of work in this area include [16, 39, 89, 90]. Recent developments enabling real-time...version of the VRP . Jozefowiez, et al. [85] study a bi-objective CTP which minimizes the total route cost ( f1(R)) and the distance from the nodes to be

  5. The temporal dynamics of heading perception in the presence of moving objects.

    Science.gov (United States)

    Layton, Oliver W; Fajen, Brett R

    2016-01-01

    Many forms of locomotion rely on the ability to accurately perceive one's direction of locomotion (i.e., heading) based on optic flow. Although accurate in rigid environments, heading judgments may be biased when independently moving objects are present. The aim of this study was to systematically investigate the conditions in which moving objects influence heading perception, with a focus on the temporal dynamics and the mechanisms underlying this bias. Subjects viewed stimuli simulating linear self-motion in the presence of a moving object and judged their direction of heading. Experiments 1 and 2 revealed that heading perception is biased when the object crosses or almost crosses the observer's future path toward the end of the trial, but not when the object crosses earlier in the trial. Nonetheless, heading perception is not based entirely on the instantaneous optic flow toward the end of the trial. This was demonstrated in Experiment 3 by varying the portion of the earlier part of the trial leading up to the last frame that was presented to subjects. When the stimulus duration was long enough to include the part of the trial before the moving object crossed the observer's path, heading judgments were less biased. The findings suggest that heading perception is affected by the temporal evolution of optic flow. The time course of dorsal medial superior temporal area (MSTd) neuron responses may play a crucial role in perceiving heading in the presence of moving objects, a property not captured by many existing models.

  6. Mixture of Switching Linear Dynamics to Discover Behavior Patterns in Object Tracks.

    Science.gov (United States)

    Kooij, Julian F P; Englebienne, Gwenn; Gavrila, Dariu M

    2016-02-01

    We present a novel non-parametric Bayesian model to jointly discover the dynamics of low-level actions and high-level behaviors of tracked objects. In our approach, actions capture both linear, low-level object dynamics, and an additional spatial distribution on where the dynamic occurs. Furthermore, behavior classes capture high-level temporal motion dependencies in Markov chains of actions, thus each learned behavior is a switching linear dynamical system. The number of actions and behaviors is discovered from the data itself using Dirichlet Processes. We are especially interested in cases where tracks can exhibit large kinematic and spatial variations, e.g. person tracks in open environments, as found in the visual surveillance and intelligent vehicle domains. The model handles real-valued features directly, so no information is lost by quantizing measurements into 'visual words', and variations in standing, walking and running can be discovered without discrete thresholds. We describe inference using Markov Chain Monte Carlo sampling and validate our approach on several artificial and real-world pedestrian track datasets from the surveillance and intelligent vehicle domain. We show that our model can distinguish between relevant behavior patterns that an existing state-of-the-art hierarchical model for clustering and simpler model variants cannot. The software and the artificial and surveillance datasets are made publicly available for benchmarking purposes.

  7. Dynamics modelling and Hybrid Suppression Control of space robots performing cooperative object manipulation

    Science.gov (United States)

    Zarafshan, P.; Moosavian, S. Ali A.

    2013-10-01

    Dynamics modelling and control of multi-body space robotic systems composed of rigid and flexible elements is elaborated here. Control of such systems is highly complicated due to severe under-actuated condition caused by flexible elements, and an inherent uneven nonlinear dynamics. Therefore, developing a compact dynamics model with the requirement of limited computations is extremely useful for controller design, also to develop simulation studies in support of design improvement, and finally for practical implementations. In this paper, the Rigid-Flexible Interactive dynamics Modelling (RFIM) approach is introduced as a combination of Lagrange and Newton-Euler methods, in which the motion equations of rigid and flexible members are separately developed in an explicit closed form. These equations are then assembled and solved simultaneously at each time step by considering the mutual interaction and constraint forces. The proposed approach yields a compact model rather than common accumulation approach that leads to a massive set of equations in which the dynamics of flexible elements is united with the dynamics equations of rigid members. To reveal such merits of this new approach, a Hybrid Suppression Control (HSC) for a cooperative object manipulation task will be proposed, and applied to usual space systems. A Wheeled Mobile Robotic (WMR) system with flexible appendages as a typical space rover is considered which contains a rigid main body equipped with two manipulating arms and two flexible solar panels, and next a Space Free Flying Robotic system (SFFR) with flexible members is studied. Modelling verification of these complicated systems is vigorously performed using ANSYS and ADAMS programs, while the limited computations of RFIM approach provides an efficient tool for the proposed controller design. Furthermore, it will be shown that the vibrations of the flexible solar panels results in disturbing forces on the base which may produce undesirable errors

  8. Designs and Algorithms to Map Eye Tracking Data with Dynamic Multielement Moving Objects

    Science.gov (United States)

    Mandal, Saptarshi

    2016-01-01

    Design concepts and algorithms were developed to address the eye tracking analysis issues that arise when (1) participants interrogate dynamic multielement objects that can overlap on the display and (2) visual angle error of the eye trackers is incapable of providing exact eye fixation coordinates. These issues were addressed by (1) developing dynamic areas of interests (AOIs) in the form of either convex or rectangular shapes to represent the moving and shape-changing multielement objects, (2) introducing the concept of AOI gap tolerance (AGT) that controls the size of the AOIs to address the overlapping and visual angle error issues, and (3) finding a near optimal AGT value. The approach was tested in the context of air traffic control (ATC) operations where air traffic controller specialists (ATCSs) interrogated multiple moving aircraft on a radar display to detect and control the aircraft for the purpose of maintaining safe and expeditious air transportation. In addition, we show how eye tracking analysis results can differ based on how we define dynamic AOIs to determine eye fixations on moving objects. The results serve as a framework to more accurately analyze eye tracking data and to better support the analysis of human performance. PMID:27725830

  9. Designs and Algorithms to Map Eye Tracking Data with Dynamic Multielement Moving Objects

    Directory of Open Access Journals (Sweden)

    Ziho Kang

    2016-01-01

    Full Text Available Design concepts and algorithms were developed to address the eye tracking analysis issues that arise when (1 participants interrogate dynamic multielement objects that can overlap on the display and (2 visual angle error of the eye trackers is incapable of providing exact eye fixation coordinates. These issues were addressed by (1 developing dynamic areas of interests (AOIs in the form of either convex or rectangular shapes to represent the moving and shape-changing multielement objects, (2 introducing the concept of AOI gap tolerance (AGT that controls the size of the AOIs to address the overlapping and visual angle error issues, and (3 finding a near optimal AGT value. The approach was tested in the context of air traffic control (ATC operations where air traffic controller specialists (ATCSs interrogated multiple moving aircraft on a radar display to detect and control the aircraft for the purpose of maintaining safe and expeditious air transportation. In addition, we show how eye tracking analysis results can differ based on how we define dynamic AOIs to determine eye fixations on moving objects. The results serve as a framework to more accurately analyze eye tracking data and to better support the analysis of human performance.

  10. Texture-defined objects influence responses of blowfly motion-sensitive neurons under natural dynamical conditions

    Directory of Open Access Journals (Sweden)

    Thomas W. Ullrich

    2014-04-01

    Full Text Available The responses of visual interneurons of flies involved in the processing of motion information do not only depend on the velocity, but also on other stimulus parameters, such as the contrast and the spatial frequency content of the stimulus pattern. These dependencies have been known for long, but it is still an open question how they affect the neurons’ performance in extracting information about the structure of the environment under the specific dynamical conditions of natural flight. Free-flight of blowflies is characterized by sequences of phases of translational movements lasting for just 30-100 milliseconds interspersed with even shorter and extremely rapid saccade-like rotational shifts in flight and gaze direction. Previous studies already analyzed how nearby objects, leading to relative motion on the retina with respect to a more distant background, influenced the response of a class of fly motion sensitive visual interneurons, the HS cells. In the present study, we focused on objects that differed from their background by discontinuities either in their brightness contrast or in their spatial frequency content. We found strong object-induced effects on the membrane potential even during the short intersaccadic intervals, if the background contrast was small and the object contrast sufficiently high. The object evoked similar response increments provided that it contained higher spatial frequencies than the background, but not under reversed conditions. This asymmetry in the response behavior is partly a consequence of the depolarization level induced by the background. Thus, our results suggest that, under the specific dynamical conditions of natural flight, i.e. on a very short timescale, the responses of HS cells represent object information depending on the polarity of the difference between object and background contrast and spatial frequency content.

  11. Testing accommodation or modification? The effects of integrated object representation on enhancing geometry performance in children with and without geometry difficulties.

    Science.gov (United States)

    Zhang, Dake; Wang, Qiu; Ding, Yi; Liu, Jeremy Jian

    2014-01-01

    According to the National Council of Teachers of Mathematics, geometry and spatial sense are fundamental components of mathematics learning. However, learning disabilities (LD) research has shown that many K-12 students encounter particular geometry difficulties (GD). This study examined the effect of an integrated object representation (IOR) accommodation on the test performance of students with GD compared to students without GD. Participants were 118 elementary students who took a researcher-developed geometry problem solving test under both a standard testing condition and an IOR accommodation condition. A total of 36 students who were classified with GD scored below 40% correct in the geometry problem solving test in the standard testing condition, and 82 students who were classified without GD scored equal to or above 40% correct in the same test and condition. All students were tested in both standard testing condition and IOR accommodation condition. The results from both ANOVA and regression discontinuity (RD) analyses suggested that students with GD benefited more than students without GD from the IOR accommodation. Implications of the study are discussed in terms of providing accommodations for students with mathematics learning difficulties and recommending RD design in LD research.

  12. FPGA implementation of a modified FitzHugh-Nagumo neuron based causal neural network for compact internal representation of dynamic environments

    Science.gov (United States)

    Salas-Paracuellos, L.; Alba, Luis; Villacorta-Atienza, Jose A.; Makarov, Valeri A.

    2011-05-01

    Animals for surviving have developed cognitive abilities allowing them an abstract representation of the environment. This internal representation (IR) may contain a huge amount of information concerning the evolution and interactions of the animal and its surroundings. The temporal information is needed for IRs of dynamic environments and is one of the most subtle points in its implementation as the information needed to generate the IR may eventually increase dramatically. Some recent studies have proposed the compaction of the spatiotemporal information into only space, leading to a stable structure suitable to be the base for complex cognitive processes in what has been called Compact Internal Representation (CIR). The Compact Internal Representation is especially suited to be implemented in autonomous robots as it provides global strategies for the interaction with real environments. This paper describes an FPGA implementation of a Causal Neural Network based on a modified FitzHugh-Nagumo neuron to generate a Compact Internal Representation of dynamic environments for roving robots, developed under the framework of SPARK and SPARK II European project, to avoid dynamic and static obstacles.

  13. Representation of Dissolved Organic Carbon in the JULES Dynamic Global Vegetation Model

    Science.gov (United States)

    Nakhavali, Mahdi; Friedlingstein, Pierre; Guenet, Bertrand; Ciais, Philip

    2017-04-01

    Current global models of the carbon cycle consider only vertical gas exchanges between terrestrial or oceanic reservoirs and the atmosphere, hence not considering lateral transport of carbon from the continent to the oceans. This also means that such models implicitly consider that all the CO2 which is not respired to the atmosphere is stored on land, hence overestimating the land sink of carbon. Moving toward a boundless carbon cycle that is integrating the whole continuum from land to ocean to atmosphere is needed in order to better understand Earth's carbon cycle and to make more reliable projection of its future. Here we present an original representation of Dissolved Organic Carbon (DOC) processes in the Joint UK Land Environment Simulator (JULES). The standard version of JULES represent energy, water and carbon cycles and exchanges with the atmosphere, but only account for water run-off, not including export of carbon from terrestrial ecosystems to the aquatic environments. The aim of the project is to include in JULES a representation of DOC production in terrestrial soils, due to incomplete decomposition of organic matter, its decomposition to the atmosphere, and its export to the river network by leaching. In new developed version of JULES (JULES-DOCM), DOC pools, based on their decomposition rate, are classified into labile and recalcitrant within 3 meters of soil. Based on turnover rate, DOC coming from plant material pools and microbial biomass is directed to labile pool, while DOC from humus is directed to recalcitrant pool. Both of these pools have free (dissolved) and locked (adsorbed) form where just the free pool is subjected to decomposition and leaching. DOC production and decomposition are controlled by rate modifiers (moisture, temperature, vegetation fraction and decomposition rate) at each soil layer. Decomposed DOC is released to the atmosphere following a fixed carbon use efficiency. Leaching accounts for both surface (runoff) and

  14. Representing the object of controversy: the case of the molecular clock.

    Science.gov (United States)

    Dietrich, Michael R

    2007-01-01

    Through a case study of the controversies surrounding the molecular clock, this paper examines the role of visual representation in the dynamics of scientific controversies. Representations of the molecular clock themselves became objects of controversy and so were not a means for closure. Instead visual representations of the molecular clock became tools for the further articulation of an ongoing controversy.

  15. Dynamic Self-Occlusion Avoidance Approach Based on the Depth Image Sequence of Moving Visual Object

    Directory of Open Access Journals (Sweden)

    Shihui Zhang

    2016-01-01

    Full Text Available How to avoid the self-occlusion of a moving object is a challenging problem. An approach for dynamically avoiding self-occlusion is proposed based on the depth image sequence of moving visual object. Firstly, two adjacent depth images of a moving object are acquired and each pixel’s 3D coordinates in two adjacent depth images are calculated by utilizing antiprojection transformation. On this basis, the best view model is constructed according to the self-occlusion information in the second depth image. Secondly, the Gaussian curvature feature matrix corresponding to each depth image is calculated by using the pixels’ 3D coordinates. Thirdly, based on the characteristic that the Gaussian curvature is the intrinsic invariant of a surface, the object motion estimation is implemented by matching two Gaussian curvature feature matrices and using the coordinates’ changes of the matched 3D points. Finally, combining the best view model and the motion estimation result, the optimization theory is adopted for planning the camera behavior to accomplish dynamic self-occlusion avoidance process. Experimental results demonstrate the proposed approach is feasible and effective.

  16. Brief Report: Representational Momentum for Dynamic Facial Expressions in Pervasive Developmental Disorder

    Science.gov (United States)

    Uono, Shota; Sato, Wataru; Toichi, Motomi

    2010-01-01

    Individuals with pervasive developmental disorder (PDD) have difficulty with social communication via emotional facial expressions, but behavioral studies involving static images have reported inconsistent findings about emotion recognition. We investigated whether dynamic presentation of facial expression would enhance subjective perception of…

  17. Field diffusion-like representation and experimental identification of a dynamic magnetization property

    Energy Technology Data Exchange (ETDEWEB)

    Maloberti, Olivier [LEG-INPG/UJF-CNRS UMR 5529: BP 46, 38402 Saint Martin d' Heres cedex (France) and Schneider Electric Corporate Research and Developments, 37 quai Paul Louis Merlin, 38050 Grenoble cedex 9 (France)]. E-mail: olivier.maloberti@schneider-electric.com; Kedous-Lebouc, A. [LEG-INPG/UJF-CNRS UMR 5529: BP 46, 38402 Saint Martin d' Heres cedex (France); Geoffroy, O. [LLN-UJF/INPG-CNRS UPR 5051: 25 avenue des Martyrs, 38050 Grenoble cedex 9 (France); Meunier, G. [LEG-INPG/UJF-CNRS UMR 5529: BP 46, 38402 Saint Martin d' Heres cedex (France); Mazauric, V. [Schneider Electric Corporate Research and Developments, 37 quai Paul Louis Merlin, 38050 Grenoble cedex 9 (France)

    2006-09-15

    So as to fuse dynamic magnetization properties of soft materials with the electromagnetism theory, we investigate the inclusion of microscopic reversal processes related to domains and walls in macroscopic Maxwell equations. We first introduce a model for independent walls and the unidirectional motion mechanism; then we characterize one sample with measurements and analytical calculations in case of one-dimensional linear problems.

  18. Syntactic computations in the language network: Characterising dynamic network properties using representational similarity analysis

    Directory of Open Access Journals (Sweden)

    Lorraine Komisarjevsky Tyler

    2013-05-01

    Full Text Available The core human capacity of syntactic analysis involves a left hemisphere network involving left inferior frontal gyrus (LIFG and posterior middle temporal gyrus (LMTG and the anatomical connections between them. Here we use MEG to determine the spatio-temporal properties of syntactic computations in this network. Listeners heard spoken sentences containing a local syntactic ambiguity (e.g. …landing planes…, at the offset of which they heard a disambiguating verb and decided whether it was an acceptable/unacceptable continuation of the sentence. We charted the time-course of processing and resolving syntactic ambiguity by measuring MEG responses from the onset of each word in the ambiguous phrase and the disambiguating word. We used representational similarity analysis (RSA to characterize syntactic information represented in the LIFG and LpMTG over time and to investigate their relationship to each other. Testing a variety of lexico-syntactic and ambiguity models against the MEG data, our results suggest early lexico-syntactic responses in the LpMTG and later effects of ambiguity in the LIFG, pointing to a clear differentiation in the functional roles of these two regions. Our results suggest the LpMTG represents and transmits lexical information to the LIFG, which responds to and resolves the ambiguity.

  19. Dynamic NMDAR-mediated properties of place cells during the object place memory task

    Directory of Open Access Journals (Sweden)

    Thomas William Faust

    2013-12-01

    Full Text Available N-methyl-D-aspartate receptors (NMDAR in the hippocampus participate in encoding and recalling the location of objects in the environment, but the ensemble mechanisms by which NMDARs mediate these processes have not been completely elucidated. To address this issue, we examined the firing patterns of place cells in the dorsal CA1 area of the hippocampus of mice (n = 7 that performed an object place memory (OPM task, consisting of familiarization (T1, sample (T2 and choice (T3 trials, after systemic injection of 3-((±2-carboxypiperazin-4ylpropyl-1-phosphate (CPP, a specific NMDAR antagonist. Place cell properties under CPP (CPP–PCs were compared to those after control saline injection (SAL–PCs in the same mice. We analyzed place cells across the OPM task to determine whether they signaled the introduction or movement of objects by NMDAR-mediated changes of their spatial coding. On T2, when two objects were first introduced to a familiar chamber, CPP–PCs and SAL–PCs showed stable, vanishing or moving place fields in addition to changes in spatial information (SI. These metrics were comparable between groups. Remarkably, previously inactive CPP–PCs (with place fields emerging de novo on T2 had significantly weaker SI increases than SAL–PCs. On T3, when one object was moved, CPP–PCs showed reduced center-of-mass (COM shift of their place fields. Indeed, a subset of SAL–PCs with large COM shifts (>7 cm was largely absent in the CPP condition. Notably, for SAL–PCs that exhibited COM shifts, those initially close to the moving object followed the trajectory of the object, whereas those far from the object did the opposite. Our results strongly suggest that the SI changes and COM shifts of place fields that occur during the OPM task reflect key dynamic properties that are mediated by NMDARs and might be responsible for binding object identity with location.

  20. Dynamic NMDAR-mediated properties of place cells during the object place memory task.

    Science.gov (United States)

    Faust, Thomas W; Robbiati, Sergio; Huerta, Tomás S; Huerta, Patricio T

    2013-01-01

    N-methyl-D-aspartate receptors (NMDAR) in the hippocampus participate in encoding and recalling the location of objects in the environment, but the ensemble mechanisms by which NMDARs mediate these processes have not been completely elucidated. To address this issue, we examined the firing patterns of place cells in the dorsal CA1 area of the hippocampus of mice (n = 7) that performed an object place memory (OPM) task, consisting of familiarization (T1), sample (T2), and choice (T3) trials, after systemic injection of 3-[(±)2-carboxypiperazin-4yl]propyl-1-phosphate (CPP), a specific NMDAR antagonist. Place cell properties under CPP (CPP-PCs) were compared to those after control saline injection (SAL-PCs) in the same mice. We analyzed place cells across the OPM task to determine whether they signaled the introduction or movement of objects by NMDAR-mediated changes of their spatial coding. On T2, when two objects were first introduced to a familiar chamber, CPP-PCs and SAL-PCs showed stable, vanishing or moving place fields in addition to changes in spatial information (SI). These metrics were comparable between groups. Remarkably, previously inactive CPP-PCs (with place fields emerging de novo on T2) had significantly weaker SI increases than SAL-PCs. On T3, when one object was moved, CPP-PCs showed reduced center-of-mass (COM) shift of their place fields. Indeed, a subset of SAL-PCs with large COM shifts (>7 cm) was largely absent in the CPP condition. Notably, for SAL-PCs that exhibited COM shifts, those initially close to the moving object followed the trajectory of the object, whereas those far from the object did the opposite. Our results strongly suggest that the SI changes and COM shifts of place fields that occur during the OPM task reflect key dynamic properties that are mediated by NMDARs and might be responsible for binding object identity with location.

  1. The Dynamics of IT Boundary Objects, Information Infrastructures, and Organisational Identities

    DEFF Research Database (Denmark)

    Gal, Uri; Lyytinen, Kalle; Yoo, Youngjin

    2008-01-01

    of the organisations that use them. We propose a model that outlines the relationships among the three concepts and illustrate its dynamics by presenting two case studies that describe the introduction of three-dimensional modelling technologies into the architecture, engineering, and construction industry. Based......In recent years, more companies engage in collaborative cross-organisational practices to achieve their business objectives. To cooperate effectively across boundaries requires organisations to overcome the tension between their distinct backgrounds and the need to create shared understandings...... with their partners for collaboration. This requires the creation of shared artefacts such as boundary objects. Whereas the past work on boundary objects has highlighted their role as translation devices, we examine them in relation to the information infrastructures within which they are embedded, and the identities...

  2. A multi-objective framework for dynamic transmission expansion planning in competitive electricity market

    Energy Technology Data Exchange (ETDEWEB)

    Foroud, Asghar Akbari; Abdoos, Ali Akbar; Keypour, Reza; Amirahmadi, Meisam [Electric and Computer Engineering Faculty, Semnan University, Semnan (Iran)

    2010-10-15

    Restructuring of power system has changed the traditional planning objectives and introduced challenges in the field of Transmission Expansion Planning (TEP). Due to these changes, new approaches and criteria are needed for transmission planning in deregulated environment. Therefore, in this paper, a dynamic expansion methodology is presented using a multi-objective optimization framework. Investment cost, congestion cost and reliability are considered in the optimization as three objectives. To overcome the difficulties in solving the non-convex and mixed integer nature of the optimization problems, a Non-Dominated Sorting Genetic Algorithm (NSGA II) approach is used followed by a fuzzy decision making analysis to obtain the final optimal solution. The planning methodology has been demonstrated on the IEEE 24-bus test system and north-east of Iran national 400 kV transmission grid to show the feasibility and capabilities of the proposed algorithm in electricity market environment. (author)

  3. Delaunay-Object-Dynamics: cell mechanics with a 3D kinetic and dynamic weighted Delaunay-triangulation.

    Science.gov (United States)

    Meyer-Hermann, Michael

    2008-01-01

    Mathematical methods in Biology are of increasing relevance for understanding the control and the dynamics of biological systems with medical relevance. In particular, agent-based methods turn more and more important because of fast increasing computational power which makes even large systems accessible. An overview of different mathematical methods used in Theoretical Biology is provided and a novel agent-based method for cell mechanics based on Delaunay-triangulations and Voronoi-tessellations is explained in more detail: The Delaunay-Object-Dynamics method. It is claimed that the model combines physically realistic cell mechanics with a reasonable computational load. The power of the approach is illustrated with two examples, avascular tumor growth and genesis of lymphoid tissue in a cell-flow equilibrium.

  4. Moving object detection using dynamic motion modelling from UAV aerial images.

    Science.gov (United States)

    Saif, A F M Saifuddin; Prabuwono, Anton Satria; Mahayuddin, Zainal Rasyid

    2014-01-01

    Motion analysis based moving object detection from UAV aerial image is still an unsolved issue due to inconsideration of proper motion estimation. Existing moving object detection approaches from UAV aerial images did not deal with motion based pixel intensity measurement to detect moving object robustly. Besides current research on moving object detection from UAV aerial images mostly depends on either frame difference or segmentation approach separately. There are two main purposes for this research: firstly to develop a new motion model called DMM (dynamic motion model) and secondly to apply the proposed segmentation approach SUED (segmentation using edge based dilation) using frame difference embedded together with DMM model. The proposed DMM model provides effective search windows based on the highest pixel intensity to segment only specific area for moving object rather than searching the whole area of the frame using SUED. At each stage of the proposed scheme, experimental fusion of the DMM and SUED produces extracted moving objects faithfully. Experimental result reveals that the proposed DMM and SUED have successfully demonstrated the validity of the proposed methodology.

  5. Convergence of Object Focused Simultaneous Estimation of Optical Flow and State Dynamics

    Directory of Open Access Journals (Sweden)

    Nicholas Bauer

    2014-10-01

    Full Text Available The purpose of this study is to prove the convergence of the simultaneous estimation of the optical flow and object state (SEOS method. The SEOS method utilizes dynamic object parameter information when calculating optical flow in tracking a moving object within a video stream. Optical flow estimation for the SEOS method requires the minimization of an error function containing the object's physical parameter data. When this function is discretized, the Euler-Lagrange equations form a system of linear equations. The system is arranged such that its property matrix is positive definite symmetric, proving the convergence of the Gauss-Seidel iterative methods. The system of linear equations produced by SEOS can alternatively be resolved by Jacobi iterative schemes. The positive definite symmetric property is not sufficient for Jacobi convergence. The convergence of SEOS for a block diagonal Jacobi is proved by analysing the Euclidean norm of the Jacobi matrix. In this paper, we also investigate the use of SEOS for tracking individual objects within a video sequence. The illustrations provided show the effectiveness of SEOS for localizing objects within a video sequence and generating optical flow results.

  6. Molecular-dynamics Simulation-based Cohesive Zone Representation of Intergranular Fracture Processes in Aluminum

    Science.gov (United States)

    Yamakov, Vesselin I.; Saether, Erik; Phillips, Dawn R.; Glaessgen, Edward H.

    2006-01-01

    A traction-displacement relationship that may be embedded into a cohesive zone model for microscale problems of intergranular fracture is extracted from atomistic molecular-dynamics simulations. A molecular-dynamics model for crack propagation under steady-state conditions is developed to analyze intergranular fracture along a flat 99 [1 1 0] symmetric tilt grain boundary in aluminum. Under hydrostatic tensile load, the simulation reveals asymmetric crack propagation in the two opposite directions along the grain boundary. In one direction, the crack propagates in a brittle manner by cleavage with very little or no dislocation emission, and in the other direction, the propagation is ductile through the mechanism of deformation twinning. This behavior is consistent with the Rice criterion for cleavage vs. dislocation blunting transition at the crack tip. The preference for twinning to dislocation slip is in agreement with the predictions of the Tadmor and Hai criterion. A comparison with finite element calculations shows that while the stress field around the brittle crack tip follows the expected elastic solution for the given boundary conditions of the model, the stress field around the twinning crack tip has a strong plastic contribution. Through the definition of a Cohesive-Zone-Volume-Element an atomistic analog to a continuum cohesive zone model element - the results from the molecular-dynamics simulation are recast to obtain an average continuum traction-displacement relationship to represent cohesive zone interaction along a characteristic length of the grain boundary interface for the cases of ductile and brittle decohesion. Keywords: Crack-tip plasticity; Cohesive zone model; Grain boundary decohesion; Intergranular fracture; Molecular-dynamics simulation

  7. Dynamic and interactive generation of object handling behaviors by a small humanoid robot using a dynamic neural network model.

    Science.gov (United States)

    Ito, Masato; Noda, Kuniaki; Hoshino, Yukiko; Tani, Jun

    2006-04-01

    This study presents experiments on the learning of object handling behaviors by a small humanoid robot using a dynamic neural network model, the recurrent neural network with parametric bias (RNNPB). The first experiment showed that after the robot learned different types of ball handling behaviors using human direct teaching, the robot was able to generate adequate ball handling motor sequences situated to the relative position between the robot's hands and the ball. The same scheme was applied to a block handling learning task where it was shown that the robot can switch among learned different block handling sequences, situated to the ways of interaction by human supporters. Our analysis showed that entrainment of the internal memory structures of the RNNPB through the interactions of the objects and the human supporters are the essential mechanisms for those observed situated behaviors of the robot.

  8. Compact Graph Representations and Parallel Connectivity Algorithms for Massive Dynamic Network Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Madduri, Kamesh; Bader, David A.

    2009-02-15

    Graph-theoretic abstractions are extensively used to analyze massive data sets. Temporal data streams from socioeconomic interactions, social networking web sites, communication traffic, and scientific computing can be intuitively modeled as graphs. We present the first study of novel high-performance combinatorial techniques for analyzing large-scale information networks, encapsulating dynamic interaction data in the order of billions of entities. We present new data structures to represent dynamic interaction networks, and discuss algorithms for processing parallel insertions and deletions of edges in small-world networks. With these new approaches, we achieve an average performance rate of 25 million structural updates per second and a parallel speedup of nearly28 on a 64-way Sun UltraSPARC T2 multicore processor, for insertions and deletions to a small-world network of 33.5 million vertices and 268 million edges. We also design parallel implementations of fundamental dynamic graph kernels related to connectivity and centrality queries. Our implementations are freely distributed as part of the open-source SNAP (Small-world Network Analysis and Partitioning) complex network analysis framework.

  9. Insular cortex representation of dynamic mechanical allodynia in trigeminal neuropathic rats.

    Science.gov (United States)

    Alvarez, Pedro; Dieb, Wisam; Hafidi, Aziz; Voisin, Daniel L; Dallel, Radhouane

    2009-01-01

    Dynamic mechanical allodynia is a widespread symptom of neuropathic pain for which mechanisms are still poorly understood. The present study investigated the organization of dynamic mechanical allodynia processing in the rat insular cortex after chronic constriction injury to the infraorbital nerve (IoN-CCI). Two weeks after unilateral IoN-CCI, rats showed a dramatic bilateral trigeminal dynamic mechanical allodynia. Light, moving stroking of the infraorbital skin resulted in strong, bilateral upregulation of extracellular-signal regulated kinase phosphorylation (pERK-1/2) in the insular cortex of IoN-CCI animals but not sham rats, in whose levels were similar to those of unstimulated IoN-CCI rats. pERK-1/2 was located in neuronal cells only. Stimulus-evoked pERK-1/2 immunopositive cell bodies displayed rostrocaudal gradient and layer selective distribution in the insula, being predominant in the rostral insula and in layers II-III of the dysgranular and to a lesser extent, of the agranular insular cortex. In layers II-III of the rostral dysgranular insular cortex, intense pERK also extended into distal dendrites, up to layer I. These results demonstrate that trigeminal nerve injury induces a significant alteration in the insular cortex processing of tactile stimuli and suggest that ERK phosphorylation contributes to the mechanisms underlying abnormal pain perception under this condition.

  10. Obtaining a Pragmatic Representation of Fire Disturbance in Dynamic Vegetation Models by Assimilating Earth Observation Data

    Science.gov (United States)

    Kantzas, Euripides; Quegan, Shaun

    2015-04-01

    Fire constitutes a violent and unpredictable pathway of carbon from the terrestrial biosphere into the atmosphere. Despite fire emissions being in many biomes of similar magnitude to that of Net Ecosystem Exchange, even the most complex Dynamic Vegetation Models (DVMs) embedded in IPCC General Circulation Models poorly represent fire behavior and dynamics, a fact which still remains understated. As DVMs operate on a deterministic, grid cell-by-grid cell basis they are unable to describe a host of important fire characteristics such as its propagation, magnitude of area burned and stochastic nature. Here we address these issues by describing a model-independent methodology which assimilates Earth Observation (EO) data by employing image analysis techniques and algorithms to offer a realistic fire disturbance regime in a DVM. This novel approach, with minimum model restructuring, manages to retain the Fire Return Interval produced by the model whilst assigning pragmatic characteristics to its fire outputs thus allowing realistic simulations of fire-related processes such as carbon injection into the atmosphere and permafrost degradation. We focus our simulations in the Arctic and specifically Canada and Russia and we offer a snippet of how this approach permits models to engage in post-fire dynamics hitherto absent from any other model regardless of complexity.

  11. 3D shape measurement of objects with high dynamic range of surface reflectivity.

    Science.gov (United States)

    Liu, Gui-hua; Liu, Xian-Yong; Feng, Quan-Yuan

    2011-08-10

    This paper presents a method that allows a conventional dual-camera structured light system to directly acquire the three-dimensional shape of the whole surface of an object with high dynamic range of surface reflectivity. To reduce the degradation in area-based correlation caused by specular highlights and diffused darkness, we first disregard these highly specular and dark pixels. Then, to solve this problem and further obtain unmatched area data, this binocular vision system was also used as two camera-projector monocular systems operated from different viewing angles at the same time to fill in missing data of the binocular reconstruction. This method involves producing measurable images by integrating such techniques as multiple exposures and high dynamic range imaging to ensure the capture of high-quality phase of each point. An image-segmentation technique was also introduced to distinguish which monocular system is suitable to reconstruct a certain lost point accurately. Our experiments demonstrate that these techniques extended the measurable areas on the high dynamic range of surface reflectivity such as specular objects or scenes with high contrast to the whole projector-illuminated field.

  12. The Effect of Dynamic and Interactive Mathematics Learning Environments (DIMLE), Supporting Multiple Representations, on Perceptions of Elementary Mathematics Pre-Service Teachers in Problem Solving Process

    Science.gov (United States)

    Ozdemir, S.; Reis, Z. Ayvaz

    2013-01-01

    Mathematics is an important discipline, providing crucial tools, such as problem solving, to improve our cognitive abilities. In order to solve a problem, it is better to envision and represent through multiple means. Multiple representations can help a person to redefine a problem with his/her own words in that envisioning process. Dynamic and…

  13. Low-dimensional representation of near-wall dynamics in shear flows, with implications to wall-models

    Science.gov (United States)

    Schmid, P. J.; Sayadi, T.

    2017-03-01

    The dynamics of coherent structures near the wall of a turbulent boundary layer is investigated with the aim of a low-dimensional representation of its essential features. Based on a triple decomposition into mean, coherent and incoherent motion and a dynamic mode decomposition to recover statistical information about the incoherent part of the flow field, a driven linear system coupling first- and second-order moments of the coherent structures is derived and analysed. The transfer function for this system, evaluated for a wall-parallel plane, confirms a strong bias towards streamwise elongated structures, and is proposed as an `impedance' boundary condition which replaces the bulk of the transport between the coherent velocity field and the coherent Reynolds stresses, thus acting as a wall model for large-eddy simulations (LES). It is interesting to note that the boundary condition is non-local in space and time. The extracted model is capable of reproducing the principal Reynolds stress components for the pretransitional, transitional and fully turbulent boundary layer.

  14. Real-Time Projection-Based Augmented Reality System for Dynamic Objects in the Performing Arts

    Directory of Open Access Journals (Sweden)

    Jaewoon Lee

    2015-02-01

    Full Text Available This paper describes the case study of applying projection-based augmented reality, especially for dynamic objects in live performing shows, such as plays, dancing, or musicals. Our study aims to project imagery correctly inside the silhouettes of flexible objects, in other words, live actors or the surface of actor’s costumes; the silhouette transforms its own shape frequently. To realize this work, we implemented a special projection system based on the real-time masking technique, that is to say real-time projection-based augmented reality system for dynamic objects in performing arts. We installed the sets on a stage for live performance, and rehearsed particular scenes of a musical. In live performance, using projection-based augmented reality technology enhances technical and theatrical aspects which were not possible with existing video projection techniques. The projected images on the surfaces of actor’s costume could not only express the particular scene of a performance more effectively, but also lead the audience to an extraordinary visual experience.

  15. Detection of static and dynamic objects in nontransparent media and opaque water

    Science.gov (United States)

    Ginzburg, Vera M.

    1998-09-01

    Holographic methods for observation of stationary and moving objects located behind a non-transparent screen, inside nontransparent construction or in opaque (turbulent) water are discussed. In the first, case, microwave holography is used. In particular, a stationary microwave facility or a holographic video camera with a picture frequency of 20 Hz is used. Defects inside various large concrete construction elements and protection lids were found. An image of a live dog behind a non-transparent wall was recorded. In the second case, ultrasound radiation was used. In particular, water surface disturbances caused by the radiation pressure of ultrasound waves passing across underwater objects were recorded. Two methods were created; one based on the effects of refraction and diffraction of a laser beam by water surface disturbances, and another based on the Talbot effect. It is shown that the first method can be used for detection of dynamic underwater objects crossing the sound beam. The Talbot effect method permits, besides detection, formation of images of these objects. Examples are shown of detection of live fish in opaque water and formation of images of small (approximately 1.5 cm2) motionless objects.

  16. 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.

  17. Shifty: A Weight-Shifting Dynamic Passive Haptic Proxy to Enhance Object Perception in Virtual Reality.

    Science.gov (United States)

    Zenner, Andre; Kruger, Antonio

    2017-04-01

    We define the concept of Dynamic Passive Haptic Feedback (DPHF) for virtual reality by introducing the weight-shifting physical DPHF proxy object Shifty. This concept combines actuators known from active haptics and physical proxies known from passive haptics to construct proxies that automatically adapt their passive haptic feedback. We describe the concept behind our ungrounded weight-shifting DPHF proxy Shifty and the implementation of our prototype. We then investigate how Shifty can, by automatically changing its internal weight distribution, enhance the user's perception of virtual objects interacted with in two experiments. In a first experiment, we show that Shifty can enhance the perception of virtual objects changing in shape, especially in length and thickness. Here, Shifty was shown to increase the user's fun and perceived realism significantly, compared to an equivalent passive haptic proxy. In a second experiment, Shifty is used to pick up virtual objects of different virtual weights. The results show that Shifty enhances the perception of weight and thus the perceived realism by adapting its kinesthetic feedback to the picked-up virtual object. In the same experiment, we additionally show that specific combinations of haptic, visual and auditory feedback during the pick-up interaction help to compensate for visual-haptic mismatch perceived during the shifting process.

  18. Sediment dynamics in the Mekong basin- a multi-objective calibration on discharge and sediment load

    Science.gov (United States)

    Luedtke, Stefan; Apel, Heiko; Viet Dung, Nguyen; Merz, Bruno

    2013-04-01

    The Mekong delta is one of the most extensively used deltas world wide and provides natural resources to more than 17 million people. Environmental issues in the Mekong delta are closely linked to water usage and availability. In addition, the sediment input to the floodplains during the annual flood plays a crucial role in terms of nutrient supply to agriculture. Since flood magnitudes and sediment delivery are driven by human activities and hydrological processes along the entire Mekong river, it is highly important to assess the dynamics upstream of the Mekong delta. This study applies the hydrological model SWIM to the watershed upstream of Kratie/Cambodia with a size of approximately 650.000 km2 and gives a quantitative depiction on the sediment and discharge dynamics. The model is driven by different, mostly globally available data sources. After the identification of the sensitive parameters, a multi objective calibration, namely the NSGA-II algorithm, is applied. The model simulates the discharge values well, e.g. by capturing the annual flood season and sediment dynamics. The next steps comprise an assessment of different sources of uncertainty that are incorporated in the model. This includes the climate input data and the sparsely available and highly variable sediment data. Eventually, the study shall provide a basis to examine the future developments along the Mekong river, for example, quantifying the impacts of potential reservoirs on the flow regime and sediment dynamics.

  19. Lightweight object oriented structure analysis: tools for building tools to analyze molecular dynamics simulations.

    Science.gov (United States)

    Romo, Tod D; Leioatts, Nicholas; Grossfield, Alan

    2014-12-15

    LOOS (Lightweight Object Oriented Structure-analysis) is a C++ library designed to facilitate making novel tools for analyzing molecular dynamics simulations by abstracting out the repetitive tasks, allowing developers to focus on the scientifically relevant part of the problem. LOOS supports input using the native file formats of most common biomolecular simulation packages, including CHARMM, NAMD, Amber, Tinker, and Gromacs. A dynamic atom selection language based on the C expression syntax is included and is easily accessible to the tool-writer. In addition, LOOS is bundled with over 140 prebuilt tools, including suites of tools for analyzing simulation convergence, three-dimensional histograms, and elastic network models. Through modern C++ design, LOOS is both simple to develop with (requiring knowledge of only four core classes and a few utility functions) and is easily extensible. A python interface to the core classes is also provided, further facilitating tool development.

  20. Lax representation of the hyperbolic van Diejen dynamics with two coupling parameters

    CERN Document Server

    Pusztai, B G

    2016-01-01

    In this paper, we construct a Lax pair for the classical hyperbolic van Diejen system with two independent coupling parameters. Built upon this construction, we show that the dynamics can be solved by a projection method, which in turn allows us to initiate the study of the scattering properties. As a consequence, we prove the equivalence between the first integrals provided by the eigenvalues of the Lax matrix and the family of van Diejen's commuting Hamiltonians. Also, at the end of the paper, we propose a candidate for the Lax matrix of the hyperbolic van Diejen system with three independent coupling constants.

  1. An exact representation of the fermion dynamics in terms of Poisson processes

    CERN Document Server

    Beccaria, M; De Angelis, G F; Jona-Lasinio, G; Beccaria, Matteo; Presilla, Carlo; Angelis, Gian Fabrizio De; Jona-Lasinio, Giovanni

    1999-01-01

    We present a simple derivation of a Feynman-Kac type formula to study fermionic systems. In this approach the real time or the imaginary time dynamics is expressed in terms of the evolution of a collection of Poisson processes. A computer implementation of this formula leads to a family of algorithms parametrized by the values of the jump rates of the Poisson processes. From these an optimal algorithm can be chosen which coincides with the Green Function Monte Carlo (GFMC) method in the limit when the latter becomes exact.

  2. Electronic excitation dynamics in multichromophoric systems described via a polaron-representation master equation.

    Science.gov (United States)

    Kolli, Avinash; Nazir, Ahsan; Olaya-Castro, Alexandra

    2011-10-21

    We derive a many-site version of the non-Markovian time-convolutionless polaron master equation [Jang et al., J. Chem Phys. 129, 101104 (2008)] to describe electronic excitation dynamics in multichromophoric systems. By treating electronic and vibrational degrees of freedom in a combined frame (polaron frame), this theory is capable of interpolating between weak and strong exciton-phonon coupling and is able to account for initial non-equilibrium bath states and spatially correlated environments. Besides outlining a general expression for the expected value of any electronic system observable in the original frame, we also discuss implications of the Markovian and Secular approximations highlighting that they need not hold in the untransformed frame despite being strictly satisfied in the polaron frame. The key features of the theory are illustrated using as an example a four-site subsystem of the Fenna-Mathews-Olson light-harvesting complex. For a spectral density including a localised mode, we show that oscillations of site populations may only be observed when non-equilibrium bath effects are taken into account. Furthermore, we illustrate how this formalism allows us to identify the electronic and vibrational components of the oscillatory dynamics.

  3. Object image correction using an X-ray dynamical diffraction Fraunhofer hologram.

    Science.gov (United States)

    Balyan, Minas K

    2014-03-01

    Taking into account background correction and using Fourier analysis, a numerical method of an object image correction using an X-ray dynamical diffraction Fraunhofer hologram is presented. An example of the image correction of a cylindrical beryllium wire is considered. A background correction of second-order iteration leads to an almost precise reconstruction of the real part of the amplitude transmission coefficient and improves the imaginary part compared with that without a background correction. Using Fourier analysis of the reconstructed transmission coefficient, non-physical oscillations can be avoided. This method can be applied for the determination of the complex amplitude transmission coefficient of amplitude as well as phase objects, and can be used in X-ray microscopy.

  4. Representation Elements of Spatial Thinking

    Science.gov (United States)

    Fiantika, F. R.

    2017-04-01

    This paper aims to add a reference in revealing spatial thinking. There several definitions of spatial thinking but it is not easy to defining it. We can start to discuss the concept, its basic a forming representation. Initially, the five sense catch the natural phenomenon and forward it to memory for processing. Abstraction plays a role in processing information into a concept. There are two types of representation, namely internal representation and external representation. The internal representation is also known as mental representation; this representation is in the human mind. The external representation may include images, auditory and kinesthetic which can be used to describe, explain and communicate the structure, operation, the function of the object as well as relationships. There are two main elements, representations properties and object relationships. These elements play a role in forming a representation.

  5. Dynamic Potential Intensity: An improved representation of the ocean’s impact on tropical cyclones

    Energy Technology Data Exchange (ETDEWEB)

    Balaguru, Karthik; Foltz, Gregory R.; Leung, Ruby L.; D' Asaro, Eric; Emanuel, Kerry A.; Liu, Hailong; Zedler, Sarah E.

    2015-08-18

    To incorporate the effects of tropical cyclone (TC)-induced upper ocean mixing and sea surface temperature (SST) cooling on TC intensification, a vertical average of temperature down to a fixed depth was proposed as a replacement for SST within the framework of air-sea coupled Potential Intensity (PI). However, the depth to which TC-induced mixing penetrates may vary substantially with ocean stratification and storm state. To account for these effects, here we develop a “Dynamic Potential Intensity” (DPI) based on considerations of stratified fluid turbulence. For the Argo period 2004–2013 and the three major TC basins of the Northern Hemisphere, we show that the DPI explains 11–32% of the variance in TC intensification, compared to 0–16% using previous methods. The improvement obtained using the DPI is particularly large in the eastern Pacific where the thermocline is shallow and ocean stratification effects are strong.

  6. Improving Success Ratio of Object Search in Highly-Dynamic Mobile P2P Networks

    Science.gov (United States)

    Takeshita, Kei; Sasabe, Masahiro; Nakano, Hirotaka

    Mobile Ad Hoc Networks (MANETs) are temporal and infrastructure-independent wireless networks that consist of mobile nodes. For instance, a MANET can be used as an emergent network for communication among people when a disaster occurred. Since there is no central server in the network, each node has to find out its desired information (objects) by itself. Constructing a mobile Peer-to-Peer (P2P) network over the MANET can support the object search. Some researchers proposed construction schemes of mobile P2P networks, such as Ekta and MADPastry. They integrated DHT-based application-layer routing and network-layer routing to increase search efficiency. Furthermore, MADPastry proposed a clustering method which groups the overlay nodes according to their physical distance. However, it has also been pointed out that the search efficiency deteriorates in highly dynamic environments where nodes quickly move around. In this paper, we focus on route disappearances in the network layer which cause the deterioration of search efficiency. We describe the detail of this problem and evaluate quantitatively it through simulation experiments. We extend MADPastry by introducing a method sharing objects among nodes in a cluster. Through simulation experiments, we show that the proposed method can achieve up to 2.5 times larger success rate of object search than MADPastry.

  7. A genetic algorithm for a bi-objective mathematical model for dynamic virtual cell formation problem

    Science.gov (United States)

    Moradgholi, Mostafa; Paydar, Mohammad Mahdi; Mahdavi, Iraj; Jouzdani, Javid

    2016-05-01

    Nowadays, with the increasing pressure of the competitive business environment and demand for diverse products, manufacturers are force to seek for solutions that reduce production costs and rise product quality. Cellular manufacturing system (CMS), as a means to this end, has been a point of attraction to both researchers and practitioners. Limitations of cell formation problem (CFP), as one of important topics in CMS, have led to the introduction of virtual CMS (VCMS). This research addresses a bi-objective dynamic virtual cell formation problem (DVCFP) with the objective of finding the optimal formation of cells, considering the material handling costs, fixed machine installation costs and variable production costs of machines and workforce. Furthermore, we consider different skills on different machines in workforce assignment in a multi-period planning horizon. The bi-objective model is transformed to a single-objective fuzzy goal programming model and to show its performance; numerical examples are solved using the LINGO software. In addition, genetic algorithm (GA) is customized to tackle large-scale instances of the problems to show the performance of the solution method.

  8. Development of the Object-Oriented Dynamic Simulation Models Using Visual C++ Freeware

    Directory of Open Access Journals (Sweden)

    Alexander I. Kozynchenko

    2016-01-01

    Full Text Available The paper mostly focuses on the methodological and programming aspects of developing a versatile desktop framework to provide the available basis for the high-performance simulation of dynamical models of different kinds and for diverse applications. So the paper gives some basic structure for creating a dynamical simulation model in C++ which is built on the Win32 platform with an interactive multiwindow interface and uses the lightweight Visual C++ Express as a free integrated development environment. The resultant simulation framework could be a more acceptable alternative to other solutions developed on the basis of commercial tools like Borland C++ or Visual C++ Professional, not to mention the domain specific languages and more specialized ready-made software such as Matlab, Simulink, and Modelica. This approach seems to be justified in the case of complex research object-oriented dynamical models having nonstandard structure, relationships, algorithms, and solvers, as it allows developing solutions of high flexibility. The essence of the model framework is shown using a case study of simulation of moving charged particles in the electrostatic field. The simulation model possesses the necessary visualization and control features such as an interactive input, real time graphical and text output, start, stop, and rate control.

  9. Internal Representation of Task Rules by Recurrent Dynamics: The Importance of the Diversity of Neural Responses

    Science.gov (United States)

    Rigotti, Mattia; Rubin, Daniel Ben Dayan; Wang, Xiao-Jing; Fusi, Stefano

    2010-01-01

    Neural activity of behaving animals, especially in the prefrontal cortex, is highly heterogeneous, with selective responses to diverse aspects of the executed task. We propose a general model of recurrent neural networks that perform complex rule-based tasks, and we show that the diversity of neuronal responses plays a fundamental role when the behavioral responses are context-dependent. Specifically, we found that when the inner mental states encoding the task rules are represented by stable patterns of neural activity (attractors of the neural dynamics), the neurons must be selective for combinations of sensory stimuli and inner mental states. Such mixed selectivity is easily obtained by neurons that connect with random synaptic strengths both to the recurrent network and to neurons encoding sensory inputs. The number of randomly connected neurons needed to solve a task is on average only three times as large as the number of neurons needed in a network designed ad hoc. Moreover, the number of needed neurons grows only linearly with the number of task-relevant events and mental states, provided that each neuron responds to a large proportion of events (dense/distributed coding). A biologically realistic implementation of the model captures several aspects of the activity recorded from monkeys performing context-dependent tasks. Our findings explain the importance of the diversity of neural responses and provide us with simple and general principles for designing attractor neural networks that perform complex computation. PMID:21048899

  10. Dynamics of a scalar field in a polymer-like representation

    Science.gov (United States)

    Han, Muxin; Ma, Yongge

    2006-04-01

    In the last 20 years, loop quantum gravity, a background-independent approach to unify general relativity and quantum mechanics, has been widely investigated. We consider the quantum dynamics of a real massless scalar field coupled to gravity in this framework. A Hamiltonian operator for the scalar field can be well defined in the coupled diffeomorphism-invariant Hilbert space, which is both self-adjoint and positive. On the other hand, the Hamiltonian constraint operator for the scalar field coupled to gravity can be well defined in the coupled kinematical Hilbert space. There are one-parameter ambiguities due to scalar field in the construction of both operators. The results heighten our confidence that there is no divergence within this background-independent and diffeomorphism-invariant quantization approach of matter coupled to gravity. Moreover, to avoid possible quantum anomaly, the master constraint programme can be carried out in this coupled system by employing a self-adjoint master constraint operator on the diffeomorphism-invariant Hilbert space.

  11. Internal representation of task rules by recurrent dynamics: the importance of the diversity of neural responses

    Directory of Open Access Journals (Sweden)

    Mattia Rigotti

    2010-10-01

    Full Text Available Neural activity of behaving animals, especially in the prefrontal cortex, is highly heterogeneous, with selective responses to diverse aspects of the executed task. We propose a general model of recurrent neural networks that perform complex rule-based tasks, and we show that the diversity of neuronal responses plays a fundamental role when the behavioral responses are context dependent. Specifically, we found that when the inner mental states encoding the task rules are represented by stable patterns of neural activity (attractors of the neural dynamics, the neurons must be selective for combinations of sensory stimuli and inner mental states. Such mixed selectivity is easily obtained by neurons that connect with random synaptic strengths both to the recurrent network and to neurons encoding sensory inputs. The number of randomly connected neurons needed to solve a task is on average only three times as large as the number of neurons needed in a network designed ad hoc. Moreover, the number of needed neurons grows only linearly with the number of task-relevant events and mental states, provided that each neuron responds to a large proportion of events (dense/distributed coding. A biologically realistic implementation of the model captures several aspects of the activity recorded from monkeys performing context dependent tasks. Our findings explain the importance of the diversity of neural responses and provide us with simple and general principles for designing attractor neural networks that perform complex computation.

  12. Operational Automatic Remote Sensing Image Understanding Systems: Beyond Geographic Object-Based and Object-Oriented Image Analysis (GEOBIA/GEOOIA. Part 2: Novel system Architecture, Information/Knowledge Representation, Algorithm Design and Implementation

    Directory of Open Access Journals (Sweden)

    Luigi Boschetti

    2012-09-01

    Full Text Available According to literature and despite their commercial success, state-of-the-art two-stage non-iterative geographic object-based image analysis (GEOBIA systems and three-stage iterative geographic object-oriented image analysis (GEOOIA systems, where GEOOIA/GEOBIA, remain affected by a lack of productivity, general consensus and research. To outperform the Quality Indexes of Operativeness (OQIs of existing GEOBIA/GEOOIA systems in compliance with the Quality Assurance Framework for Earth Observation (QA4EO guidelines, this methodological work is split into two parts. Based on an original multi-disciplinary Strengths, Weaknesses, Opportunities and Threats (SWOT analysis of the GEOBIA/GEOOIA approaches, the first part of this work promotes a shift of learning paradigm in the pre-attentive vision first stage of a remote sensing (RS image understanding system (RS-IUS, from sub-symbolic statistical model-based (inductive image segmentation to symbolic physical model-based (deductive image preliminary classification capable of accomplishing image sub-symbolic segmentation and image symbolic pre-classification simultaneously. In the present second part of this work, a novel hybrid (combined deductive and inductive RS-IUS architecture featuring a symbolic deductive pre-attentive vision first stage is proposed and discussed in terms of: (a computational theory (system design, (b information/knowledge representation, (c algorithm design and (d implementation. As proof-of-concept of symbolic physical model-based pre-attentive vision first stage, the spectral knowledge-based, operational, near real-time, multi-sensor, multi-resolution, application-independent Satellite Image Automatic Mapper™ (SIAM™ is selected from existing literature. To the best of these authors’ knowledge, this is the first time a symbolic syntactic inference system, like SIAM™, is made available to the RS community for operational use in a RS-IUS pre-attentive vision first stage

  13. Development of Dynamic Coupling Measurement of Distributed Object Oriented Software Based on Trace Events

    Directory of Open Access Journals (Sweden)

    S. Babu

    2012-02-01

    Full Text Available Software metrics are increasingly playing a central role in the planning and control of softwaredevelopment projects. Coupling measures have important applications in software development andmaintenance. Existing literature on software metrics is mainly focused on centralized systems, while workin the area of distributed systems, particularly in service-oriented systems, is scarce. Distributed systemswith service oriented components are even more heterogeneous networking and execution environment.Traditional coupling measures take into account only “static” couplings. They do not account for“dynamic” couplings due to polymorphism and may significantly underestimate the complexity of softwareand misjudge the need for code inspection, testing and debugging. This is expected to result in poorpredictive accuracy of the quality models in distributed Object Oriented systems that utilize static couplingmeasurements. In order to overcome these issues, we propose a hybrid model in Distributed ObjectOriented Software for measure the coupling dynamically. In the proposed method, there are three stepssuch as Instrumentation process, Post processing and Coupling measurement. Initially the instrumentationprocess is done. In this process the instrumented JVM that has been modified to trace method calls. Duringthis process, three trace files are created namely .prf, .clp, .svp. In the second step, the information in thesefile are merged. At the end of this step, the merged detailed trace of each JVM contains pointers to themerged trace files of the other JVM such that the path of every remote call from the client to the server canbe uniquely identified. Finally, the coupling metrics are measured dynamically. The implementation resultsshow that the proposed system will effectively measure the coupling metrics dynamically.

  14. Automatic media-adventitia IVUS image segmentation based on sparse representation framework and dynamic directional active contour model.

    Science.gov (United States)

    Zakeri, Fahimeh Sadat; Setarehdan, Seyed Kamaledin; Norouzi, Somayye

    2017-03-25

    Segmentation of the arterial wall boundaries from intravascular ultrasound images is an important image processing task in order to quantify arterial wall characteristics such as shape, area, thickness and eccentricity. Since manual segmentation of these boundaries is a laborious and time consuming procedure, many researchers attempted to develop (semi-) automatic segmentation techniques as a powerful tool for educational and clinical purposes in the past but as yet there is no any clinically approved method in the market. This paper presents a deterministic-statistical strategy for automatic media-adventitia border detection by a fourfold algorithm. First, a smoothed initial contour is extracted based on the classification in the sparse representation framework which is combined with the dynamic directional convolution vector field. Next, an active contour model is utilized for the propagation of the initial contour toward the interested borders. Finally, the extracted contour is refined in the leakage, side branch openings and calcification regions based on the image texture patterns. The performance of the proposed algorithm is evaluated by comparing the results to those manually traced borders by an expert on 312 different IVUS images obtained from four different patients. The statistical analysis of the results demonstrates the efficiency of the proposed method in the media-adventitia border detection with enough consistency in the leakage and calcification regions. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. The effect of acoustically levitated objects on the dynamics of ultrasonic actuators

    Science.gov (United States)

    Ilssar, D.; Bucher, I.

    2017-03-01

    This paper presents a comprehensive model, coupling a piezoelectric actuator operating at ultrasonic frequencies to a near-field acoustically levitated object through a compressible thin layer of gas such that the combined dynamic response of the system can be predicted. The latter is derived by introducing a simplified model of the nonlinear squeezed layer of gas and a variational model of the solid structure and the piezoelectric elements. Since the harmonic forces applied by the entrapped fluid depend on the levitated object's height and vertical motion, the latter affects the impedance of the driving surface, affecting the natural frequencies, damping ratios, and amplification of the actuator. Thus, the developed model is helpful when devising a resonance tracking algorithm aimed to excite a near-field acoustic levitation based apparatus optimally. Validation of the suggested model was carried out using a focused experimental setup geared to eliminate the effects that were already verified in the past. In agreement with the model, the experimental results showed that the natural frequency and damping ratio of a designated mode decrease monotonically with the levitated object's average height, whereas the amplification of the mode increases with the levitation height.

  16. Multi-Objective Dynamic Economic Dispatch of Microgrid Systems Including Vehicle-to-Grid

    Directory of Open Access Journals (Sweden)

    Haitao Liu

    2015-05-01

    Full Text Available Based on the characteristics of electric vehicles (EVs, this paper establishes the load models of EVs under the autonomous charging mode and the coordinated charging and discharging mode. Integrating the EVs into a microgrid system which includes wind turbines (WTs, photovoltaic arrays (PVs, diesel engines (DEs, fuel cells (FCs and a storage battery (BS, this paper establishes multi-objective economic dispatch models of a microgrid, including the lowest operating cost, the least carbon dioxide emissions, and the lowest pollutant treatment cost. After converting the multi-objective functions to a single objective function by using the judgment matrix method, we analyze the dynamic economic dispatch of the microgrid system including vehicle-to-grid (V2G with an improved particle swarm optimization algorithm under different operation control strategies. With the example system, the proposed models and strategies are verified and analyzed. Simulation results show that the microgrid system with EVs under the coordinated charging and discharging mode has better operation economics than the autonomous charging mode. Meanwhile, the greater the load fluctuation is, the higher the operating cost of the microgrid system is.

  17. Enhanced codebook algorithm for fast moving object detection from dynamic background using scene visual perception

    Science.gov (United States)

    Mousse, Mikaël A.; Motamed, Cina; Ezin, Eugène C.

    2016-11-01

    The detection of moving objects in a video sequence is the first step in an automatic video surveillance system. This work proposes an enhancement of a codebook-based algorithm for moving objects extraction. The proposed algorithm used a perceptual-based approach to optimize foreground information extraction complexity by using a modified codebook algorithm. The purpose of the adaptive strategy is to reduce the computational complexity of the foreground detection algorithm while maintaining its global accuracy. In this algorithm, we use a superpixels segmentation approach to model the spatial dependencies between pixels. The processing of the superpixels is controlled to focus it on the superpixels that are near to the possible location of foreground objects. The performance of the proposed algorithm is evaluated and compared to other algorithms of the state of the art using a public dataset that proposes sequences with a dynamic background. Experimental results prove that the proposed algorithm obtained the best the frame processing rate during the foreground detection.

  18. Animal Representations on Ceremonial Objects Found in the Tumulus at Črnolica pri Šentjurju at the Foot of Rifnik

    Directory of Open Access Journals (Sweden)

    Iztok Vrenčur

    2013-07-01

    . However, the Črnolica specimen differs from the normative form of other horse tripods, offering its own stylistic solutions. Its abstract blend of iconographical features resembles the fantastic and often bizarre monsters of the Orientalising style iconography. If we presume that the equine and anthropomorphic iconography of the Italic horse tripods alludes to a mythological story unknown today, then the tripod from Črnolica deliberately excludes such allusions. Objects with both Geometric and Orientalising style elements are common in the Etruria of the early 7th century BC. The branched fragment which carries the ram’s head, tending towards naturalism, presumably belonged to a big tripod of Etruscan provenience. The ram is a motif typical of the Italic Orientalising style, which developed under eastern Mediterranean influences. The popular Orientalising iconography was thus copied by local Italic craftsmen, with the result that the figural representation – probably for the first time in the prehistory of this and the neighbouring territories – did not allude to a mythological story but had a purely decorative value. The Etruscan objects found in the Črnolica tumulus belong to two successive Italic art styles. They were probably not brought to Rifnik at the same time but had gradually accumulated in the settlement by the second half of the 7th century BC, when they were deposited in the richly furnished grave of a local aristocrat. With their zoomorphic iconography, the imports of the Črnolica mound are representatives of the increasing Orientalising impulses from Etruria, which resulted in the formation of the celebrated situla art.

  19. Multi-objective four-dimensional vehicle motion planning in large dynamic environments.

    Science.gov (United States)

    Wu, Paul P-Y; Campbell, Duncan; Merz, Torsten

    2011-06-01

    This paper presents Multi-Step A∗ (MSA∗), a search algorithm based on A∗ for multi-objective 4-D vehicle motion planning (three spatial and one time dimensions). The research is principally motivated by the need for offline and online motion planning for autonomous unmanned aerial vehicles (UAVs). For UAVs operating in large dynamic uncertain 4-D environments, the motion plan consists of a sequence of connected linear tracks (or trajectory segments). The track angle and velocity are important parameters that are often restricted by assumptions and a grid geometry in conventional motion planners. Many existing planners also fail to incorporate multiple decision criteria and constraints such as wind, fuel, dynamic obstacles, and the rules of the air. It is shown that MSA∗ finds a cost optimal solution using variable length, angle, and velocity trajectory segments. These segments are approximated with a grid-based cell sequence that provides an inherent tolerance to uncertainty. The computational efficiency is achieved by using variable successor operators to create a multiresolution memory-efficient lattice sampling structure. The simulation studies on the UAV flight planning problem show that MSA∗ meets the time constraints of online replanning and finds paths of equivalent cost but in a quarter of the time (on average) of a vector neighborhood-based A∗.

  20. Geostationary secular dynamics revisited: application to high area-to-mass ratio objects

    CERN Document Server

    Gachet, Fabien; Pucacco, Giuseppe; Efthymiopoulos, Christos

    2016-01-01

    The long-term dynamics of the geostationary Earth orbits (GEO) is revisited through the application of canonical perturbation theory. We consider a Hamiltonian model accounting for all major perturbations: geopotential at order and degree two, lunisolar perturbations with a realistic model for the Sun and Moon orbits, and solar radiation pressure. The long-term dynamics of the GEO region has been studied both numerically and analytically, in view of the relevance of such studies to the issue of space debris or to the disposal of GEO satellites. Past studies focused on the orbital evolution of objects around a nominal solution, hereafter called the forced equilibrium solution, which shows a particularly strong dependence on the area-to-mass ratio. Here, we i) give theoretical estimates for the long-term behavior of such orbits, and ii) we examine the nature of the forced equilibrium itself. In the lowest approximation, the forced equilibrium implies motion with a constant non-zero average `forced eccentricity'...

  1. Dynamics and control of a solar collector system for near Earth object deflection *

    Institute of Scientific and Technical Information of China (English)

    Shen-Ping Gong; Jun-Feng Li; Yun-Feng Gao

    2011-01-01

    A solar collector system is a possible method using solar energy to deflect Earth-threatening near-Earth objects. We investigate the dynamics and control of a solar collector system including a main collector (MC) and secondary collector (SC).The MC is used to collect the sunlight to its focal point, where the SC is placed and directs the collected light to an asteroid. Both the relative position and attitude of the two collectors should be accurately controlled to achieve the desired optical path. First,the dynamical equation of the relative motion of the two collectors in the vicinity of the asteroid is modeled. Secondly, the nonlinear sliding-mode method is employed to design a control law to achieve the desired configuration of the two collectors. Finally,the deflection capability of this solar collector system is compared with those of the gravitational tractor and solar sail gravitational tractor. The results show that the solar collector is much more efficient with respect to deflection capability.

  2. Representational Thickness

    DEFF Research Database (Denmark)

    Mullins, Michael

    elements into the process of design. Through its immersive properties, virtual reality allows access to a spatial experience of a computer model very different to both screen based simulations as well as traditional forms of architectural representation. The dissertation focuses on processes of the current......Contemporary communicational and informational processes contribute to the shaping of our physical environment by having a powerful influence on the process of design. Applications of virtual reality (VR) are transforming the way architecture is conceived and produced by introducing dynamic...... by ‘professionals’ to ‘laypeople’. The thesis articulates problems in VR’s current application, specifically the CAVE and Panorama theatres, and seeks an understanding of how these problems may be addressed. The central questions that have motivated this research project are thus: What is architectural VR...

  3. English- and Mandarin-learning infants' discrimination of actions and objects in dynamic events.

    Science.gov (United States)

    Chen, Jie; Tardif, Twila; Pulverman, Rachel; Casasola, Marianella; Zhu, Liqi; Zheng, Xiaobei; Meng, Xiangzhi

    2015-10-01

    The present studies examined the role of linguistic experience in directing English and Mandarin learners' attention to aspects of a visual scene. Specifically, they asked whether young language learners in these 2 cultures attend to differential aspects of a word-learning situation. Two groups of English and Mandarin learners, 6-8-month-olds (n = 65) and 17-19-month-olds (n = 91), participated in 2 studies, based on a habituation paradigm, designed to test infants' discrimination between actions and objects in dynamic events. In Study 1, these stimuli were presented in silence, whereas in Study 2, a verbal label accompanied videos. Results showed that 6-8-month-olds could discriminate action changes but not object changes, whereas 17-19-month-olds could discriminate both types of changes. However, there were only very subtle cross-linguistic differences in these patterns when the scenes were presented together with a verbal label. These findings show strong evidence for universal developmental trends in attention, with somewhat weaker evidence that the differences in the types of words Mandarin- versus English-learning children produce or are exposed to affect attention to different aspects of a scene in the first 2 years of life. (c) 2015 APA, all rights reserved).

  4. Spatiotemporal dynamics of bimanual integration in human somatosensory cortex and their relevance to bimanual object manipulation.

    Science.gov (United States)

    Jung, Patrick; Klein, Johannes C; Wibral, Michael; Hoechstetter, Karsten; Bliem, Barbara; Lu, Ming-Kuei; Wahl, Mathias; Ziemann, Ulf

    2012-04-18

    Little is known about the spatiotemporal dynamics of cortical responses that integrate slightly asynchronous somatosensory inputs from both hands. This study aimed to clarify the timing and magnitude of interhemispheric interactions during early integration of bimanual somatosensory information in different somatosensory regions and their relevance for bimanual object manipulation and exploration. Using multi-fiber probabilistic diffusion tractography and MEG source analysis of conditioning-test (C-T) median nerve somatosensory evoked fields in healthy human subjects, we sought to extract measures of structural and effective callosal connectivity between different somatosensory cortical regions and correlated them with bimanual tactile task performance. Neuromagnetic responses were found in major somatosensory regions, i.e., primary somatosensory cortex SI, secondary somatosensory cortex SII, posterior parietal cortex, and premotor cortex. Contralateral to the test stimulus, SII activity was maximally suppressed by 51% at C-T intervals of 40 and 60 ms. This interhemispheric inhibition of the contralateral SII source activity correlated directly and topographically specifically with the fractional anisotropy of callosal fibers interconnecting SII. Thus, the putative pathway that mediated inhibitory interhemispheric interactions in SII was a transcallosal route from ipsilateral to contralateral SII. Moreover, interhemispheric inhibition of SII source activity correlated directly with bimanual tactile task performance. These findings were exclusive to SII. Our data suggest that early interhemispheric somatosensory integration primarily occurs in SII, is mediated by callosal fibers that interconnect homologous SII areas, and has behavioral importance for bimanual object manipulation and exploration.

  5. A Multiple Mobile Behavior-based Omni-direction Micro Robots System for Object Micromanipulation with Dynamic Cooperation

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Object micromanipulation has become an issue of primary importance industry and biomedicine.Since human manual capabilities are restricted to certain tolerances.A multi-micro-robot system for micromanipulation is described, which incorporates a dynamic cooperation strategy.A control structure of the multiple micro robots system was proposed that combine the advantages of both center control and distribute control.The dynamic cooperation strategy to the proposed multiple micro robots system handling an object in cooperation is applied.Experimental results illustrate the validity of the proposed robot system with dynamic cooperation for micromanipulation.

  6. Evaluation of covariance and information performance measures for dynamic object tracking

    Science.gov (United States)

    Yang, Chun; Blasch, Erik; Douville, Phil; Kaplan, Lance; Qiu, Di

    2010-04-01

    In surveillance and reconnaissance applications, dynamic objects are dynamically followed by track filters with sequential measurements. There are two popular implementations of tracking filters: one is the covariance or Kalman filter and the other is the information filter. Evaluation of tracking filters is important in performance optimization not only for tracking filter design but also for resource management. Typically, the information matrix is the inverse of the covariance matrix. The covariance filter-based approaches attempt to minimize the covariance matrix-based scalar indexes whereas the information filter-based methods aim at maximizing the information matrix-based scalar indexes. Such scalar performance measures include the trace, determinant, norms (1-norm, 2-norm, infinite-norm, and Forbenius norm), and eigenstructure of the covariance matrix or the information matrix and their variants. One natural question to ask is if the scalar track filter performance measures applied to the covariance matrix are equivalent to those applied to the information matrix? In this paper we show most of the scalar performance indexes are equivalent yet some are not. As a result, the indexes if used improperly would provide an "optimized" solution but in the wrong sense relative to track accuracy. The simulation indicated that all the seven indexes were successful when applied to the covariance matrix. However, the failed indexes for the information filter include the trace and the four norms (as defined in MATLAB) of the information matrix. Nevertheless, the determinant and the properly selected eigenvalue of the information matrix were successful to select the optimal sensor update configuration. The evaluation analysis of track measures can serve as a guideline to determine the suitability of performance measures for tracking filter design and resource management.

  7. Vertical dynamics of a horizontally oscillating active object in a two-dimensional granular medium

    Science.gov (United States)

    Huang, Ling; Ran, Xianwen; Blumenfeld, Raphael

    2016-12-01

    We use a discrete-element method simulation and analytical considerations to study the dynamics of a self-energized object, modeled as a disk, oscillating horizontally within a two-dimensional bed of denser and smaller particles. We find that, for given material parameters, the immersed object (IO) may rise, sink, or not change depth, depending on the oscillation amplitude and frequency, as well as on the initial depth. With time, the IO settles at a specific depth that depends on the oscillation parameters. We construct a phase diagram of this behavior in the oscillation frequency and velocity amplitude variable space. We explain the observed rich behavior by two competing effects: climbing on particles, which fill voids opening under the disk, and sinking due to bed fluidization. We present a cavity model that allows us to derive analytically general results, which agree very well with the observations and explain quantitatively the phase diagram. Our specific analytical results are the following. (i) Derivation of a critical frequency, fc, above which the IO cannot float up against gravity. We show that this frequency depends only on the gravitational acceleration and the IO size. (ii) Derivation of a minimal amplitude, Amin, below which the IO cannot rise even if the frequency is below fc. We show that this amplitude also depends only on the gravitational acceleration and the IO size. (iii) Derivation of a critical value, gc, of the IO's acceleration amplitude, below which the IO cannot sink. We show that the value of gc depends on the characteristics of both the IO and the granular bed, as well as on the initial IO's depth.

  8. A purpose-built dynamometer to objectively measure static and dynamic knee torque.

    Science.gov (United States)

    Ugbolue, U C; Kaliarntas, K T; Wearing, S C; Rowe, P J

    2011-05-01

    This paper reports the development of a purpose-built knee dynamometer (PBKD) to evaluate passive range of motion (ROM) and isometric muscle strength measurements of the knee. The PBKD uses a TorqSense rotary torque transducer and objectively measures isometric knee muscle strength in a valid and reliable manner and passive resistance to motion through range. The device and all associated instrumentation underwent dynamic and static calibration to ensure consistent and accurate measurements were obtained in terms of knee joint angular position, passive torque measures, and isometric torque measures. Eleven healthy male participants performed a knee flexion and extension task designed to evaluate knee function. The validation of the PBKD entailed measuring the consistency of measurement and accuracy of measurement. Accuracy of the PBKD was determined by comparing peak isometric muscle strength measurements against a KIN-COM machine. No significant differences were observed both passively and isometrically between cycles and between trials. This device can have widespread applications within the rehabilitation and clinical environment and could be used as a functional outcome measuring tool to distinguish pathological from non-pathological knees. The presented preliminary results indicate that reliable and accurate measurements of knee ROM and muscle strength can be obtained.

  9. Dynamic light scattering as an objective noninvasive method in veterinary ophthalmic diagnosis and research

    Science.gov (United States)

    Dubin, Stephen; Ansari, Rafat R.; Tulp, Orien; Steinberg, Sheldon; Koch, Seth; DellaVecchia, Michael A.; Cozmi, Mihaela; Victor, Mary

    1999-06-01

    The absence of verbal feedback, available from most human patients, is a major limitation in veterinary diagnosis in general and in the evaluation of ophthalmic lens opacity in particular. A novel compact dynamic light scattering (DLS) instrument, developed at NASA, offers significant mitigation to this limitation. It not only yields objective repeatable non-invasive estimation of lens opacity but also provides insight into the nature of chemical and physical alternations in the lens and other eye structures. For example, DLS measurements of the cataractous lens may be interpreted in terms of alpha crystalline protein size. In contrast to most conventional methods, the examination results are numerical and readily accommodate statistical analysis. We present results of DLS measurements in laboratory rabbits with naphthalene induced cataracts, rodents with genetically conditioned hypertension and/or diabetes mellitus; as well as applications of the DLS method in clinical veterinary patients. Use of DLS in examination of phacoemulsification fluid, urine and other biological materials, and potential applications in ocular toxically will also be discussed.

  10. The relative weight of shape and non-rigid motion cues in object perception: a model of the parameters underlying dynamic object discrimination.

    Science.gov (United States)

    Vuong, Quoc C; Friedman, Alinda; Read, Jenny C A

    2012-03-16

    Shape and motion are two dominant cues for object recognition, but it can be difficult to investigate their relative quantitative contribution to the recognition process. In the present study, we combined shape and non-rigid motion morphing to investigate the relative contributions of both types of cues to the discrimination of dynamic objects. In Experiment 1, we validated a novel parameter-based motion morphing technique using a single-part three-dimensional object. We then combined shape morphing with the novel motion morphing technique to pairs of multipart objects to create a joint shape and motion similarity space. In Experiment 2, participants were shown pairs of morphed objects from this space and responded "same" on the basis of motion-only, shape-only, or both cues. Both cue types influenced judgments: When responding to only one cue, the other cue could be ignored, although shape cues were more difficult to ignore. When responding on the basis of both cues, there was an overall bias to weight shape cues more than motion cues. Overall, our results suggest that shape influences discrimination more than motion even when both cue types have been made quantitatively equivalent in terms of their individual discriminability.

  11. Tracking of Maneuvering Complex Extended Object with Coupled Motion Kinematics and Extension Dynamics Using Range Extent Measurements.

    Science.gov (United States)

    Sun, Lifan; Ji, Baofeng; Lan, Jian; He, Zishu; Pu, Jiexin

    2017-09-22

    The key to successful maneuvering complex extended object tracking (MCEOT) using range extent measurements provided by high resolution sensors lies in accurate and effective modeling of both the extension dynamics and the centroid kinematics. During object maneuvers, the extension dynamics of an object with a complex shape is highly coupled with the centroid kinematics. However, this difficult but important problem is rarely considered and solved explicitly. In view of this, this paper proposes a general approach to modeling a maneuvering complex extended object based on Minkowski sum, so that the coupled turn maneuvers in both the centroid states and extensions can be described accurately. The new model has a concise and unified form, in which the complex extension dynamics can be simply and jointly characterized by multiple simple sub-objects' extension dynamics based on Minkowski sum. The proposed maneuvering model fits range extent measurements very well due to its favorable properties. Based on this model, an MCEOT algorithm dealing with motion and extension maneuvers is also derived. Two different cases of the turn maneuvers with known/unknown turn rates are specifically considered. The proposed algorithm which jointly estimates the kinematic state and the object extension can also be easily implemented. Simulation results demonstrate the effectiveness of the proposed modeling and tracking approaches.

  12. MENTAL STATE REPRESENTATION: SPATIOTEMPORAL CHARACTERISTICS

    Directory of Open Access Journals (Sweden)

    Alexander Oktyabrinovich Prokhorov

    2014-01-01

    Full Text Available Since the time of statement of the problem of states in psychology, the study of “sensuous” tissue – the mental state representation-takes a fundamental meaning. The problem is concluded in the following questions: “How is mental state represented in the consciousness of an individual?”, “What is the specificity of the mental state representation as distinguished from the subject-matter representation?”, “What are the mechanisms of the mental state representation occurrence and the peculiarities of its dynamics? The study of the mental state representation will allow to explain its specificity and difference from the figurative representation, the peculiarities of state explication as a representation in the consciousness and its relation with other elements of consciousness, will allow to show the regularities of the mental state representation development and its dynamics, factors, which influence the specificity of its occurrence, the regulatory role of the state representation in the vital function. From these perspectives, the article presents the results of the study of spatiotemporal characteristics of the mental state representation; reveals the peculiar features of the spatiotemporal organization of mental state representations: Relieves, specificity, magnitude, variability of indicators, changes of structural characteristics in time spans; considers the age-specific peculiar features of the spatiotemporal organization of mental state representations in terms of organization, stability, coherence and differentiated nature of spatiotemporal structures with the representatives of certain age groups.

  13. Embedded data representations

    DEFF Research Database (Denmark)

    Willett, Wesley; Jansen, Yvonne; Dragicevic, Pierre

    2017-01-01

    We introduce embedded data representations, the use of visual and physical representations of data that are deeply integrated with the physical spaces, objects, and entities to which the data refers. Technologies like lightweight wireless displays, mixed reality hardware, and autonomous vehicles...... are making it increasingly easier to display data in-context. While researchers and artists have already begun to create embedded data representations, the benefits, trade-offs, and even the language necessary to describe and compare these approaches remain unexplored. In this paper, we formalize the notion...... of physical data referents – the real-world entities and spaces to which data corresponds – and examine the relationship between referents and the visual and physical representations of their data. We differentiate situated representations, which display data in proximity to data referents, and embedded...

  14. METHODOLOGY AND RESULTS OF MOBILE OBJECT PURSUIT PROBLEM SOLUTION WITH TWO-STAGE DYNAMIC SYSTEM

    Directory of Open Access Journals (Sweden)

    A. Kiselev Mikhail

    2017-01-01

    Full Text Available The experience of developing unmanned fighting vehicles indicates that the main challenge in this field reduces itself to creating the systems which can replace the pilot both as a sensor and as the operator of the flight. This problem can be partial- ly solved by introducing remote control, but there are certain flight segments where it can only be executed under fully inde- pendent control and data support due to various reasons, such as tight time, short duration, lack of robust communication, etc. Such stages also include close-range air combat maneuvering (CRACM - a key flight segment as far as the fighter's purpose is concerned, which also places the highest demands on the fighter's design. Until recently the creation of an unmanned fighter airplane has been a fundamentally impossible task due to the absence of sensors able to provide the necessary data support to control the fighter during CRACM. However, the development prospects of aircraft hardware (passive type flush antennae, op- tico-locating panoramic view stations are indicative of producing possible solutions to this problem in the nearest future. There- fore, presently the only fundamental impediment on the way to developing an unmanned fighting aircraft is the problem of cre- ating algorithms for automatic trajectory control during CRACM. This paper presents the strategy of automatic trajectory con- trol synthesis by a two-stage dynamic system aiming to reach the conditions specified with respect to an object in pursuit. It contains certain results of control algorithm parameters impact assessment in regards to the pursuit mission effectiveness. Based on the obtained results a deduction is drawn pertaining to the efficiency of the offered method and its possible utilization in au- tomated control of an unmanned fighting aerial vehicle as well as organizing group interaction during CRACM.

  15. Formation dynamics of femtosecond laser-induced phase objects in transparent materials

    Science.gov (United States)

    Mermillod-Blondin, A.; Rosenfeld, A.; Stoian, R.; Audouard, E.

    2012-01-01

    Ultrashort pulse lasers offer the possibility to structure the bulk of transparent materials on a microscale. As a result, the optical properties of the irradiated material are locally modified in a permanent fashion. Depending on the irradiation parameters, different types of laser-induced phase objects can be expected, from uniform voxels (that can exhibit higher or lower refractive index than the bulk) to self-organized nanoplanes. We study the physical mechanisms that lead to material restructuring, with a particular emphasis on events taking place on a sub picosecond to a microsecond timescale following laser excitation. Those timescales are particularly interesting as they correspond to the temporal distances between two consecutive laser pulses when performing multiple pulse irradiation: burst microprocessing usually involves picosecond separation times and high repetition rate systems operate in the MHz range. We employ a time-resolved microscopy technique based on a phase-contrast microscope setup extended into a pump-probe scheme. This methods enables a dynamic observation of the complex refractive index in the interaction region with a time resolution better than 300 fs. In optical transmission mode, the transient absorption coefficient can be measured for different illumination wavelengths (400 nm and 800 nm). The phase-contrast mode provides qualitative information about the real part of the transient refractive index. Based on the study of those transient optical properties, we observe the onset and relaxation of the laser-generated plasma into different channels such as defect creation, sample heating, and shockwave generation. The majority of our experiments were carried out with amorphous silica, but our method can be applied to the study of all transparent media.

  16. Development of a Dynamically Configurable, Object-Oriented Framework for Distributed, Multi-modal Computational Aerospace Systems Simulation

    Science.gov (United States)

    Afjeh, Abdollah A.; Reed, John A.

    2003-01-01

    The following reports are presented on this project:A first year progress report on: Development of a Dynamically Configurable,Object-Oriented Framework for Distributed, Multi-modal Computational Aerospace Systems Simulation; A second year progress report on: Development of a Dynamically Configurable, Object-Oriented Framework for Distributed, Multi-modal Computational Aerospace Systems Simulation; An Extensible, Interchangeable and Sharable Database Model for Improving Multidisciplinary Aircraft Design; Interactive, Secure Web-enabled Aircraft Engine Simulation Using XML Databinding Integration; and Improving the Aircraft Design Process Using Web-based Modeling and Simulation.

  17. A CORBA-based object framework with patient identification translation and dynamic linking. Methods for exchanging patient data.

    Science.gov (United States)

    Wang, C; Ohe, K

    1999-03-01

    Exchanging and integration of patient data across heterogeneous databases and institutional boundaries offers many problems. We focused on two issues: (1) how to identify identical patients between different systems and institutions while lacking universal patient identifiers; and (2) how to link patient data across heterogeneous databases and institutional boundaries. To solve these problems, we created a patient identification (ID) translation model and a dynamic linking method in the Common Object Request Broker Architecture (CORBA) environment. The algorithm for the patient ID translation is based on patient attribute matching plus computer-based human checking; the method for dynamic linking is temporal mapping. By implementing these methods into computer systems with help of the distributed object computing technology, we built a prototype of a CORBA-based object framework in which the patient ID translation and dynamic linking methods were embedded. Our experiments with a Web-based user interface using the object framework and dynamic linking-through the object framework were successful. These methods are important for exchanging and integrating patient data across heterogeneous databases and institutional boundaries.

  18. Embedded Data Representations.

    Science.gov (United States)

    Willett, Wesley; Jansen, Yvonne; Dragicevic, Pierre

    2017-01-01

    We introduce embedded data representations, the use of visual and physical representations of data that are deeply integrated with the physical spaces, objects, and entities to which the data refers. Technologies like lightweight wireless displays, mixed reality hardware, and autonomous vehicles are making it increasingly easier to display data in-context. While researchers and artists have already begun to create embedded data representations, the benefits, trade-offs, and even the language necessary to describe and compare these approaches remain unexplored. In this paper, we formalize the notion of physical data referents - the real-world entities and spaces to which data corresponds - and examine the relationship between referents and the visual and physical representations of their data. We differentiate situated representations, which display data in proximity to data referents, and embedded representations, which display data so that it spatially coincides with data referents. Drawing on examples from visualization, ubiquitous computing, and art, we explore the role of spatial indirection, scale, and interaction for embedded representations. We also examine the tradeoffs between non-situated, situated, and embedded data displays, including both visualizations and physicalizations. Based on our observations, we identify a variety of design challenges for embedded data representation, and suggest opportunities for future research and applications.

  19. Evaluation of protein-protein docking model structures using all-atom molecular dynamics simulations combined with the solution theory in the energy representation.

    Science.gov (United States)

    Takemura, Kazuhiro; Guo, Hao; Sakuraba, Shun; Matubayasi, Nobuyuki; Kitao, Akio

    2012-12-07

    We propose a method to evaluate binding free energy differences among distinct protein-protein complex model structures through all-atom molecular dynamics simulations in explicit water using the solution theory in the energy representation. Complex model structures are generated from a pair of monomeric structures using the rigid-body docking program ZDOCK. After structure refinement by side chain optimization and all-atom molecular dynamics simulations in explicit water, complex models are evaluated based on the sum of their conformational and solvation free energies, the latter calculated from the energy distribution functions obtained from relatively short molecular dynamics simulations of the complex in water and of pure water based on the solution theory in the energy representation. We examined protein-protein complex model structures of two protein-protein complex systems, bovine trypsin/CMTI-1 squash inhibitor (PDB ID: 1PPE) and RNase SA/barstar (PDB ID: 1AY7), for which both complex and monomer structures were determined experimentally. For each system, we calculated the energies for the crystal complex structure and twelve generated model structures including the model most similar to the crystal structure and very different from it. In both systems, the sum of the conformational and solvation free energies tended to be lower for the structure similar to the crystal. We concluded that our energy calculation method is useful for selecting low energy complex models similar to the crystal structure from among a set of generated models.

  20. Design of pixel electronics based on asynchronous self-reset approach with floating-point output representation for high dynamic range imagers

    Energy Technology Data Exchange (ETDEWEB)

    Nascetti, A [Sapienza University of Rome, Scuola di Ingegneria Aerospaziale, Via Salaria 851/881, 00138 Roma (Italy); Valerio, P, E-mail: augusto.nascetti@uniroma1.it [Sapienza University of Rome, Dip. Ingegneria Elettronica, Via Eudossiana 18, 00184, Roma (Italy)

    2011-01-15

    A readout circuit suitable for multi-channel preamplifiers for pixellated detectors, hybrid detectors or thin film on asic imagers, for applications requiring large dynamic range such as computed tomography is discussed. The circuit implements an asynchronous self-reset with residue conversion scheme combined with a floating point representation of the input current. This solution allows to reach a very high dynamic range with good linearity while ensuring a compact output format. In particular, in the present implementation the input current range extends from 50 fA up to 820 nA corresponding to a 144 dB dynamic range which is equivalent to a 24-bit code. However the proposed scheme only uses 16 output bits for the floating point representation with 12-bit constant relative resolution: 12 bits serve for the output value itself and 4 for storing the position of the transition point between integer and fractional part. In addition, an analytical study of the achievable imaging performances shows that no significant degradation of the SNR is expected for the 12-bit constant relative resolution implementation with respect to the full 24-bit resolution scheme. Finally, the main building blocks of the circuit are analyzed in detail and their characteristics are put in relationship with the overall system performances.

  1. Standard model of knowledge representation

    Science.gov (United States)

    Yin, Wensheng

    2016-09-01

    Knowledge representation is the core of artificial intelligence research. Knowledge representation methods include predicate logic, semantic network, computer programming language, database, mathematical model, graphics language, natural language, etc. To establish the intrinsic link between various knowledge representation methods, a unified knowledge representation model is necessary. According to ontology, system theory, and control theory, a standard model of knowledge representation that reflects the change of the objective world is proposed. The model is composed of input, processing, and output. This knowledge representation method is not a contradiction to the traditional knowledge representation method. It can express knowledge in terms of multivariate and multidimensional. It can also express process knowledge, and at the same time, it has a strong ability to solve problems. In addition, the standard model of knowledge representation provides a way to solve problems of non-precision and inconsistent knowledge.

  2. Steps Towards a Method for the Formal Modeling of Dynamic Objects

    NARCIS (Netherlands)

    Wieringa, Roelf J.

    1991-01-01

    Fragments of a method to formally specify object-oriented models of a universe of discourse are presented. The task of finding such models is divided into three subtasks, object classification, event specification, and the specification of the life cycle of an object. Each of these subtasks is

  3. Path integral molecular dynamics combined with discrete-variable-representation approach: the effect of solvation structures on vibrational spectra of Cl 2 in helium clusters

    Science.gov (United States)

    Takayanagi, Toshiyuki; Shiga, Motoyuki

    2002-08-01

    The structures and vibrational frequencies of Cl 2-helium clusters have been studied using the path integral molecular dynamics method combined with the discrete-variable-representation approach. It is found that the Cl 2-helium clusters form clear shell structures comprised of rings around the Cl 2 bond. The vibrational frequencies calculated show a monotonically increasing red shift with an increase in cluster size. It can be concluded that the first solvation shell and its density around T-shaped configurations play the most important role in the observed frequency shifts.

  4. A Framework of Multi Objectives Negotiation for Dynamic Supply Chain Model

    Science.gov (United States)

    Chai, Jia Yee; Sakaguchi, Tatsuhiko; Shirase, Keiichi

    Trends of globalization and advances in Information Technology (IT) have created opportunity in collaborative manufacturing across national borders. A dynamic supply chain utilizes these advances to enable more flexibility in business cooperation. This research proposes a concurrent decision making framework for a three echelons dynamic supply chain model. The dynamic supply chain is formed by autonomous negotiation among agents based on multi agents approach. Instead of generating negotiation aspects (such as amount, price and due date) arbitrary, this framework proposes to utilize the information available at operational level of an organization in order to generate realistic negotiation aspect. The effectiveness of the proposed model is demonstrated by various case studies.

  5. Numerical reconstruction of an object image using an X-ray dynamical diffraction Fraunhofer hologram.

    Science.gov (United States)

    Balyan, Minas K

    2014-01-01

    A numerical method of reconstruction of an object image using an X-ray dynamical diffraction Fraunhofer hologram is presented. Analytical approximation methods and numerical methods of iteration are discussed. An example of a reconstruction of an image of a cylindrical beryllium wire is considered. The results of analytical approximation and zero-order iteration coincide with exact values of the amplitude complex transmission coefficient of the object as predicted by the resolution limit of the scheme, except near the edges of the object. Calculations of the first- and second-order iterations improve the result at the edges of the object. This method can be applied for determination of the complex amplitude transmission coefficient of amplitude as well as phase objects. It can be used in X-ray microscopy.

  6. A new technique for dynamic load distribution when two manipulators mutually lift a rigid object. Part 1, The proposed technique

    Energy Technology Data Exchange (ETDEWEB)

    Unseren, M.A.

    1994-04-01

    A general framework for solving the dynamic load distribution when two manipulators hold a rigid object is proposed. The underspecified problem of solving for the contact forces and torques based on the object`s equations of motion is transformed into a well specified problem. This is accomplished by augmenting the object`s equations of motion with additional equations which relate a new vector variable quantifying the internal contact force and torque degrees of freedom (DOF) as a linear function of the contact forces and torques. The resulting augmented system yields a well specified solution for the contact forces and torques in which they are separated into their motion inducing and internal components. A particular solution is suggested which enables the designer to conveniently specify what portion of the payload`s mass each manipulator is to bear. It is also shown that the results of the previous work are just a special case of the general load distribution framework described here.

  7. Kernel representations for behaviors over finite rings

    NARCIS (Netherlands)

    Kuijper, M.; Pinto, R.; Polderman, J.W.; Yamamoto, Y.

    2006-01-01

    In this paper we consider dynamical systems finite rings. The rings that we study are the integers modulo a power of a given prime. We study the theory of representations for such systems, in particular kernel representations.

  8. Application of Tripartite Entangled State Representation in Solving the Dynamics of a Kind of Three Coupled Oscillators

    Institute of Scientific and Technical Information of China (English)

    PANG Qian-Jun

    2005-01-01

    We study the eigenstate problem of a kind of three coupled oscillators in a new quantum mechanical representation composed by the spontaneous eigenvectors 〈p, q2, q3| for three operators (p1 +p2 +p3), (x3 - x2), and (x3 - x1). The eigenvalues and eigenvectors of the Hamiltonian are obtained. With the same method, the eigenstate problem of a generalized three-coupled oscillator Hamiltonian is studied, which has never been studied before.

  9. Static analysis of unbounded structures in object-oriented programs

    NARCIS (Netherlands)

    Grabe, Immo

    2012-01-01

    In this thesis we investigate different techniques and formalisms to address complexity introduced by unbounded structures in object-oriented programs. We give a representation of a weakest precondition calculus for abstract object creation in dynamic logic. Based on this calculus we define symbolic

  10. Static analysis of unbounded structures in object-oriented programs

    NARCIS (Netherlands)

    Grabe, Immo

    2012-01-01

    In this thesis we investigate different techniques and formalisms to address complexity introduced by unbounded structures in object-oriented programs. We give a representation of a weakest precondition calculus for abstract object creation in dynamic logic. Based on this calculus we define symbolic

  11. Comparison of evolutionary multi objective algorithms for the dynamic network design problem

    NARCIS (Netherlands)

    Wismans, Luc J.J.; Berkum, van Eric C.; Bliemer, Michiel C.J.

    2011-01-01

    In traffic and transport a significant portion of research and application is focused on single objective optimization, although there is rarely only one objective that is of interest. The externalities of traffic are of increasing importance for policy decisions related to the design of a road netw

  12. Temporal brain dynamics of multiple object processing: the flexibility of individuation.

    Directory of Open Access Journals (Sweden)

    Veronica Mazza

    Full Text Available The ability to process concurrently multiple visual objects is fundamental for a coherent perception of the world. A core component of this ability is the simultaneous individuation of multiple objects. Many studies have addressed the mechanism of object individuation but it remains unknown whether the visual system mandatorily individuates all relevant elements in the visual field, or whether object indexing depends on task demands. We used a neural measure of visual selection, the N2pc component, to evaluate the flexibility of multiple object individuation. In three ERP experiments, participants saw a variable number of target elements among homogenous distracters and performed either an enumeration task (Experiment 1 or a detection task, reporting whether at least one (Experiment 2 or a specified number of target elements (Experiment 3 was present. While in the enumeration task the N2pc response increased as a function of the number of targets, no such modulation was found in Experiment 2, indicating that individuation of multiple targets is not mandatory. However, a modulation of the N2pc similar to the enumeration task was visible in Experiment 3, further highlighting that object individuation is a flexible mechanism that binds indexes to object properties and locations as needed for further object processing.

  13. Web Search Engines and Indexing and Ranking the Content Object Including Metadata Elements Available at the Dynamic Information Environments

    Directory of Open Access Journals (Sweden)

    Faezeh sadat Tabatabai Amiri

    2012-10-01

    Full Text Available The purpose of this research was to make exam the indexing and ranking of XML content objects containing Dublin Core and MARC 21 metadata elements in dynamic online information environments by general search engines and comparing them together in a comparative-analytical approach. 100 XML content objects in two groups were analyzed: those with DCXML elements and those with MARCXML elements were published in website http://www.marcdcmi.ir. from late Mordad 1388 till Khordad 1389. Then the website was introduced to Google and Yahoo search engines. Google search engine was able to retrieve fully all the content objects during the study period through their Dublin Core and MARC 21 metadata elements; Yahoo search engine, however, did not respond at all. The indexing of metadata elements embedded in content objects in dynamic online information environments and different between indexing and ranking of them were examined. Findings showed all Dublin Core and MARC 21 metadata elements by Google search engine were indexed. And there was not observed difference between indexing and ranking DCXML and MARCXML metadata elements in dynamic online information environments by Google search engine.

  14. Social Representations of Responsibility in Guatemalan Students

    Directory of Open Access Journals (Sweden)

    Humberto Emilio Aguilera Arévalo

    2010-07-01

    Full Text Available The responsibility is a key concept in the twentieth century because it establishes a connection between the individual and society. Recent studies analyze the responsibility as a relational concept that connects the individual to an event and its outcomes. In that sense, the responsibility may be linked to Markova perspective on dialogicality and social representations because it activates the Ego-Alter-Object dynamic: being responsible for something (Ego toward someone (Alter, and in relation to an instance (object. This paper analyzes the social representations of responsibility in a sample of 296 university students from Guatemala, who answered six stimulus words I Responsible, I Irresponsible, Responsible Guatemalan, Irresponsible Guatemalan, Responsible European and Irresponsible European, using the natural semantic networks technique. Subsequently two questionnaires were made; one about responsibility and irresponsibility on a personal, in group and out group level, based on semantic networks obtained. Finally, factor analysis and hierarchical cluster analysis were made.

  15. The Unfairness of Equal Treatment: Objectivity in L2 Testing and Dynamic Assessment

    Science.gov (United States)

    Lantolf, James P.; Poehner, Matthew E.

    2013-01-01

    This paper considers dynamic assessment (DA) as it relates to second language (L2) development. DA is grounded in Vygotsky's (1987) sociocultural theory of mind, which holds that human consciousness emerges as a result of participation in culturally organized social activities where mediation plays a key role in guiding development. In DA, the…

  16. Multi-objective Mobile Robot Scheduling Problem with Dynamic Time Windows

    DEFF Research Database (Denmark)

    Dang, Vinh Quang; Nielsen, Izabela Ewa; Steger-Jensen, Kenn

    2012-01-01

    , simul-taneously. In operation, the feeders have to be replenished a number of times so as to maintain the manufacture of products during a planning horizon. A meth-od based on predefined characteristics of the feeders is presented to generate dynamic time windows of the feeding tasks which are dependent...

  17. Quarks, Leptons as Fermion-Boson Composite Objects and Flavor-Mixings by Substructure Dynamics

    CERN Document Server

    Matsushima, T

    1999-01-01

    A fermion-boson-type composite model for quarks and leptons is proposed. Elementary fields are only one kind of spin-1/2 and spin-0 preon. Both are in the global supersymmetric pair with the common electric charge of e/6 and belong to the fundamental representations of (3,2,2) under the spontaneously unbroken SU(3)_C*SU(2)_L*SU(2)_R gauge symmetry induced necessarily by the concept of ``Cartan connection'' equipped with ``Soldering Mechanism''. Preons are composed into subquarks which are ``intermediate clusters'' towards quarks and leptons. The mechanism of making higher generations is obtained by adding neutral scalar subquark composed of a preon-antipreon pair in the 3-state of SU(2)_{L,R}. This model predicts the CKM matrix elements : |V_{ts}|=2.6*10^{-2}},|V_{td}|=1.4*10^{-3}; the neutral pseudoscalar meson mass differences : {Delta}M_D\\approx10^{-14} GeV, {Delta}M_{B_s}\\approx10^{-11} GeV,{Delta}M_{T_u}\\approx10^{(-10\\sim{-9})} GeV and {theta}_K={\\theta}_D={\\theta}_{B_s}={\\theta}_{T_c}

  18. Defending the structural concept of representation

    Directory of Open Access Journals (Sweden)

    Andreas BARTELS

    2010-01-01

    Full Text Available The paper defends the structural concept of representation, defined by homomorphisms, against the main objections that have been raised against it: Logical objections, the objection from misrepresentation, the objection from failing necessity, and the copy theory objection. Homomorphic representations are not necessarily ‘copies’ of their representanda, and thus can convey scientific insight.

  19. Surface composition and dynamical evolution of two retrograde objects in the outer solar system: 2008 YB3 and 2005 VD

    CERN Document Server

    Pinilla-Alonso, N; Melita, M D; Lorenzi, V; Licandro, J; Carvano, J; Lazzaro, D; Carraro, G; Ali-Lagoa, V; Costa, E; Hasselmann, P H; 10.1051/0004-6361/201220030

    2013-01-01

    Most of the objects in the trans-Neptunian belt (TNb) and related populations move in prograde orbits with low eccentricity and inclination. However, the list of icy minor bodies moving in orbits with an inclination above 40 deg. has increased in recent years. The origin of these bodies, and in particular of those objects in retrograde orbits, is not well determined, and different scenarios are considered. In this paper, we present new observational and dynamical data of two objects in retrograde orbits, 2008 YB3 and 2005 VD. We find that the surface of these extreme objects is depleted of ices and does not contain the 'ultra-red' matter typical of some Centaurs. Despite small differences, these objects share common colors and spectral characteristics with the Trojans, comet nuclei, and the group of grey Centaurs. All of these populations are supposed to be covered by a mantle of dust responsible for their reddish- to neutral-color. To investigate if the surface properties and dynamical evolution of these bod...

  20. Dynamic cortical activity during the perception of three-dimensional object shape from two-dimensional random-dot motion.

    Science.gov (United States)

    Iwaki, Sunao; Bonmassar, Giorgio; Belliveau, John W

    2013-09-01

    Recent neuroimaging studies implicate that both the dorsal and ventral visual pathways, as well as the middle temporal (MT) areas which are critical for the perception of visual motion, are involved in the perception of three-dimensional (3D) structure from two-dimensional (2D) motion (3D-SFM). However, the neural dynamics underlying the reconstruction of a 3D object from 2D optic flow is not known. Here we combined magnetoencephalography (MEG) and functional MRI (fMRI) measurements to investigate the spatiotemporal brain dynamics during 3D-SFM. We manipulated parametrically the coherence of randomly moving groups of dots to create different levels of 3D perception and to study the associated changes in brain activity. At different latencies, the posterior infero-temporal (pIT), the parieto-occipital (PO), and the intraparietal (IP) regions showed increased neural activity during highly coherent motion conditions in which subjects perceived a robust 3D object. Causality analysis between these regions indicated significant causal influence from IP to pIT and from pIT to PO only in conditions where subjects perceived a robust 3D object. Current results suggest that the perception of a 3D object from 2D motion includes integration of global motion and 3D mental image processing, as well as object recognition that are accomplished by interactions between the dorsal and ventral visual pathways.

  1. Detection of biological objects using dynamic characteristics of double-walled carbon nanotubes

    Science.gov (United States)

    Patel, Ajay M.; Joshi, Anand Y.

    2015-08-01

    This study explores double-walled carbon nanotubes as the sensing devices for biological objects including viruses and bacteria. The biological objects studied include alanine with amino terminal residue, deoxyadenosine with free residue, Coronaviridae and Bartonella bacilliformis. An expression has been articulated to identify the mass of biological objects from the shift of frequency. Sensitivity of the sensor has been calculated when subjected to such biological objects. Molecular structural mechanics approach has been used for investigating the vibrational responses of zigzag and armchair double-walled carbon nanotube-based nano biosensors. The elastic properties of beam element are calculated by considering mechanical characteristics of covalent bonds between the carbon atoms in the hexagonal lattice. Spring elements are used to describe the interlayer interactions between the inner and outer tubes caused due to the van der Waals forces. The mass of each beam element is assumed as point mass at nodes coinciding with carbon atoms at inner and outer wall of DWCNT. Based on the sensitivity and the frequency shift it can be concluded that cantilever zigzag DWCNTs are better candidates for detecting the biological objects.

  2. Dynamic object recognition and tracking of mobile robot by monocular vision

    Science.gov (United States)

    Liu, Lei; Wang, Yongji

    2007-11-01

    Monocular Vision is widely used in mobile robot's motion control for its simple structure and easy using. An integrated description to distinguish and tracking the specified color targets dynamically and precisely by the Monocular Vision based on the imaging principle is the major topic of the paper. The mainline is accordance with the mechanisms of visual processing strictly, including the pretreatment and recognition processes. Specially, the color models are utilized to decrease the influence of the illumination in the paper. Some applied algorithms based on the practical application are used for image segmentation and clustering. After recognizing the target, however the monocular camera can't get depth information directly, 3D Reconstruction Principle is used to calculate the distance and direction from robot to target. To emend monocular camera reading, the laser is used after vision measuring. At last, a vision servo system is designed to realize the robot's dynamic tracking to the moving target.

  3. Parallel performance of an object-oriented contact implementation for transient solid dynamic analysis

    Science.gov (United States)

    Xiaoyong, Bai; Yingbo, He; Chengjun, Chen

    2010-06-01

    In order to make it easier to extend an finite element software framework with contact implementation for transient solid dynamic analysis, we have designed a general-purposed framework-oriented parallel contact class in this article. A parallel contact computation algorithm model has been generated based on contact schemes reported on last two decades. The class is integrated to an open source platform easily without affecting the rest code of the platform.

  4. Mobile Brain/Body Imaging (MoBI) of Physical Interaction with Dynamically Moving Objects

    Science.gov (United States)

    Jungnickel, Evelyn; Gramann, Klaus

    2016-01-01

    The non-invasive recording and analysis of human brain activity during active movements in natural working conditions is a central challenge in Neuroergonomics research. Existing brain imaging approaches do not allow for an investigation of brain dynamics during active behavior because their sensors cannot follow the movement of the signal source. However, movements that require the operator to react fast and to adapt to a dynamically changing environment occur frequently in working environments like assembly-line work, construction trade, health care, but also outside the working environment like in team sports. Overcoming the restrictions of existing imaging methods would allow for deeper insights into neurocognitive processes at workplaces that require physical interactions and thus could help to adapt work settings to the user. To investigate the brain dynamics accompanying rapid volatile movements we used a visual oddball paradigm where participants had to react to color changes either with a simple button press or by physically pointing towards a moving target. Using a mobile brain/body imaging approach (MoBI) including independent component analysis (ICA) with subsequent backprojection of cluster activity allowed for systematically describing the contribution of brain and non-brain sources to the sensor signal. The results demonstrate that visual event-related potentials (ERPs) can be analyzed for simple button presses and physical pointing responses and that it is possible to quantify the contribution of brain processes, muscle activity and eye movements to the signal recorded at the sensor level even for fast volatile arm movements with strong jerks. Using MoBI in naturalistic working environments can thus help to analyze brain dynamics in natural working conditions and help improving unhealthy or inefficient work settings. PMID:27445747

  5. Realtime Avoidance of Fast Moving Objects: A Dynamical System-based Approach

    OpenAIRE

    Khansari-Zadeh, S. M.; Billard, Aude

    2012-01-01

    In this paper, we provide an extension to our previous approach (Khansari & Billard (2012), Autonomous Robots) to perform obstacle avoidance in the presence of multiple fast moving and rotating obstacles. Our approach leverage on the notion of DS to generate robot motions that are inherently robust to perturbations and can instantly adapt to changes in the target and obstacles' positions in a dynamically moving environments. We validate our method in the challenging experiment of dodging a fa...

  6. Integrating deductive verification and symbolic execution for abstract object creation in dynamic logic

    NARCIS (Netherlands)

    C.P.T. de Gouw (Stijn); F.S. de Boer (Frank); W. Ahrendt (Wolfgang); R. Bubel (Richard)

    2016-01-01

    textabstractWe present a fully abstract weakest precondition calculus and its integration with symbolic execution. Our assertion language allows both specifying and verifying properties of objects at the abstraction level of the programming language, abstracting from a specific implementation of

  7. Dynamical Black Hole Masses of BL Lac Objects from the Sloan Digital Sky Survey

    NARCIS (Netherlands)

    Plotkin, Richard M.; Markoff, Sera; Trager, Scott C.; Anderson, Scott F.

    2012-01-01

    We measure black hole masses for 71 BL Lac objects from the Sloan Digital Sky Survey (SDSS) with redshifts out to z ∼ 0.4. We perform spectral decompositions of their nuclei from their host galaxies and measure their stellar velocity dispersions. Black hole masses are then derived from the black

  8. Dynamical black hole masses of BL Lac objects from the Sloan Digital Sky Survey

    NARCIS (Netherlands)

    Plotkin, R. M.; Markoff, S.; Trager, S. C.; Anderson, S. F.

    We measure black hole masses for 71 BL Lac objects from the Sloan Digital Sky Survey with redshifts out to z˜ 0.4. We perform spectral decompositions of their nuclei from their host galaxies and measure their stellar velocity dispersions. Black hole masses are then derived from the black hole mass -

  9. Dynamical black hole masses of BL Lac objects from the Sloan Digital Sky Survey

    NARCIS (Netherlands)

    Plotkin, R.M.; Markoff, S.; Trager, S.C.; Anderson, S.F.

    2011-01-01

    We measure black hole masses for 71 BL Lac objects from the Sloan Digital Sky Survey with redshifts out to z∼ 0.4. We perform spectral decompositions of their nuclei from their host galaxies and measure their stellar velocity dispersions. Black hole masses are then derived from the black hole mass -

  10. Dynamical Black Hole Masses of BL Lac Objects from the Sloan Digital Sky Survey

    NARCIS (Netherlands)

    Plotkin, Richard M.; Markoff, Sera; Trager, Scott C.; Anderson, Scott F.

    2012-01-01

    We measure black hole masses for 71 BL Lac objects from the Sloan Digital Sky Survey (SDSS) with redshifts out to z ∼ 0.4. We perform spectral decompositions of their nuclei from their host galaxies and measure their stellar velocity dispersions. Black hole masses are then derived from the black hol

  11. Dynamical black hole masses of BL Lac objects from the Sloan Digital Sky Survey

    NARCIS (Netherlands)

    Plotkin, R.M.; Markoff, S.; Trager, S.C.; Anderson, S.F.

    2011-01-01

    We measure black hole masses for 71 BL Lac objects from the Sloan Digital Sky Survey with redshifts out to z∼ 0.4. We perform spectral decompositions of their nuclei from their host galaxies and measure their stellar velocity dispersions. Black hole masses are then derived from the black hole mass -

  12. Dynamical black hole masses of BL Lac objects from the Sloan Digital Sky Survey

    NARCIS (Netherlands)

    Plotkin, R. M.; Markoff, S.; Trager, S. C.; Anderson, S. F.

    2011-01-01

    We measure black hole masses for 71 BL Lac objects from the Sloan Digital Sky Survey with redshifts out to z˜ 0.4. We perform spectral decompositions of their nuclei from their host galaxies and measure their stellar velocity dispersions. Black hole masses are then derived from the black hole mass -

  13. Dynamical black hole masses of BL Lac objects from the Sloan Digital Sky Survey

    NARCIS (Netherlands)

    Plotkin, R. M.; Markoff, S.; Trager, S. C.; Anderson, S. F.

    2011-01-01

    We measure black hole masses for 71 BL Lac objects from the Sloan Digital Sky Survey with redshifts out to z similar to 0.4. We perform spectral decompositions of their nuclei from their host galaxies and measure their stellar velocity dispersions. Black hole masses are then derived from the black h

  14. Multi-objective optimization of internal combustion engine by means of 1D fluid-dynamic models

    Energy Technology Data Exchange (ETDEWEB)

    D' Errico, G.; Cerri, T.; Pertusi, G. [Dipartimento di Energia, Politecnico di Milano, Via Lambruschini 4, 20156 Milan (Italy)

    2011-03-15

    The definition of an efficient optimization methodology for internal combustion engine design using 1D fluid dynamic simulation models is presented. This work aims at discussing the fundamental numerical and fluid dynamic aspects which can lead to the definition of a best practice technique, depending on the complexity of the problem to be dealt with, on the number of design parameters, objective variables and constrains. For these reasons, both single-and multi-objective problems will be addressed, where the former are still of relevant interest (i.e. optimization of engine performances), while the latter have a much wider range of applications and are often characterized by conflicting objectives. The Mesh Adaptive Direct Search (MADS) was chosen among the class of direct search methods and compared with the Genetic Algorithms to solve single-objective problems, and similarly two different algorithms were chosen and compared to solve multi-objective problems: the {epsilon}-constraint method and the NSGA-II (Non-Dominated Sorting Genetic Algorithm). A single cylinder spark ignition engine, used in a motorbike application, was chosen as test case, to allow reduced computational times, without any loss of generality of the results. The analysis evaluate the convergence and efficiency of each methodology for the different problems which are solved. The achieved goal is not the definition of an ever valid mathematical strategy, but here focus is given on the parallel application of a detailed fluid dynamic analysis and automated optimization techniques to suggest a best practice technique to be employed depending on the characteristic of the optimization problem to be solved. (author)

  15. Neural Dynamics of Object-Based Multifocal Visual Spatial Attention and Priming: Object Cueing, Useful-Field-of-View, and Crowding

    Science.gov (United States)

    Foley, Nicholas C.; Grossberg, Stephen; Mingolla, Ennio

    2012-01-01

    How are spatial and object attention coordinated to achieve rapid object learning and recognition during eye movement search? How do prefrontal priming and parietal spatial mechanisms interact to determine the reaction time costs of intra-object attention shifts, inter-object attention shifts, and shifts between visible objects and covertly cued…

  16. Robust Optimization Approach for Design for a Dynamic Cell Formation Considering Labor Utilization: Bi-objective Mathematical Mode

    Directory of Open Access Journals (Sweden)

    Hiwa Farughi

    2016-05-01

    Full Text Available In this paper, robust optimization of a bi-objective mathematical model in a dynamic cell formation problem considering labor utilization with uncertain data is carried out. The robust approach is used to reduce the effects of fluctuations of the uncertain parameters with regards to all the possible future scenarios. In this research, cost parameters of the cell formation and demand fluctuations are subject to uncertainty and a mixed-integer programming (MIP model is developed to formulate the related robust dynamic cell formation problem. Then the problem is transformed into a bi-objective linear one. The first objective function seeks to minimize relevant costs of the problem including machine procurement and relocation costs, machine variable cost, inter-cell movement and intra-cell movement costs, overtime cost and labor shifting cost between cells, machine maintenance cost, inventory, holding part cost. The second objective function seeks to minimize total man-hour deviations between cells or indeed labor utilization of the modeled.

  17. Representation of spatial and temporal variability of daily wind speed and of intense wind events over the Mediterranean Sea using dynamical downscaling: impact of the regional climate model configuration

    Directory of Open Access Journals (Sweden)

    M. Herrmann

    2011-07-01

    Full Text Available Atmospheric datasets coming from long term reanalyzes of low spatial resolution are used for different purposes. Wind over the sea is, for example, a major ingredient of oceanic simulations. However, the shortcomings of those datasets prevent them from being used without an adequate corrective preliminary treatment. Using a regional climate model (RCM to perform a dynamical downscaling of those large scale reanalyzes is one of the methods used in order to produce fields that realistically reproduce atmospheric chronology and where those shortcomings are corrected. Here we assess the influence of the configuration of the RCM used in this framework on the representation of wind speed spatial and temporal variability and intense wind events on a daily timescale. Our RCM is ALADIN-Climate, the reanalysis is ERA-40, and the studied area is the Mediterranean Sea.

    First, the dynamical downscaling significantly reduces the underestimation of daily wind speed, in average by 9 % over the whole Mediterranean. This underestimation has been corrected both globally and locally, and for the whole wind speed spectrum. The correction is the strongest for periods and regions of strong winds. The representation of spatial variability has also been significantly improved. On the other hand, the temporal correlation between the downscaled field and the observations decreases all the more that one moves eastwards, i.e. further from the atmospheric flux entry. Nonetheless, it remains ~0.7, the downscaled dataset reproduces therefore satisfactorily the real chronology.

    Second, the influence of the choice of the RCM configuration has an influence one order of magnitude smaller than the improvement induced by the initial downscaling. The use of spectral nudging or of a smaller domain helps to improve the realism of the temporal chronology. Increasing the resolution very locally (both spatially and temporally improves the representation of spatial

  18. A Parallel General Purpose Mulit-Objective Optimization Framework, with Application to Beam Dynamics

    CERN Document Server

    Ineichen, Y; Kolano, A; Bekas, C; Curioni, A; Arbenz, P

    2013-01-01

    Particle accelerators are invaluable tools for research in the basic and applied sciences, in fields such as materials science, chemistry, the biosciences, particle physics, nuclear physics and medicine. The design, commissioning, and operation of accelerator facilities is a non-trivial task, due to the large number of control parameters and the complex interplay of several conflicting design goals. We propose to tackle this problem by means of multi-objective optimization algorithms which also facilitate a parallel deployment. In order to compute solutions in a meaningful time frame we require a fast and scalable software framework. In this paper, we present the implementation of such a general-purpose framework for simulation based multi-objective optimization methods that allows the automatic investigation of optimal sets of machine parameters. The implementation is based on a master/slave paradigm, employing several masters that govern a set of slaves executing simulations and performing optimization task...

  19. Physical simulation of the long-term dynamic action of a plasma beam on a space debris object

    Science.gov (United States)

    Shuvalov, Valentin A.; Gorev, Nikolai. B.; Tokmak, Nikolai A.; Kochubei, Galina S.

    2017-03-01

    A methodology is developed for physical (laboratory) simulation of the long-term dynamic action of plasma beam high-energy ions on a space debris object with the aim of removing it to a lower orbit followed by its burning in the Earth's atmosphere. The methodology is based on the use of a criterion for the equivalence of two plasma beam exposure regimes (in the Earth' ionosphere and in laboratory conditions) and an accelerated test procedure in what concerns space debris object material sputtering and space debris object erosion by a plasma beam in the Earth's ionosphere. The space debris coating material (blanket thermal insulation) sputtering yield and normal and tangential momentum transfer coefficients are determined experimentally as a function of the ion energy and the ion beam incidence angle.

  20. Quantum dynamics calculations using symmetrized, orthogonal Weyl-Heisenberg wavelets with a phase space truncation scheme. III. Representations and calculations.

    Science.gov (United States)

    Poirier, Bill; Salam, A

    2004-07-22

    In a previous paper [J. Theo. Comput. Chem. 2, 65 (2003)], one of the authors (B.P.) presented a method for solving the multidimensional Schrodinger equation, using modified Wilson-Daubechies wavelets, and a simple phase space truncation scheme. Unprecedented numerical efficiency was achieved, enabling a ten-dimensional calculation of nearly 600 eigenvalues to be performed using direct matrix diagonalization techniques. In a second paper [J. Chem. Phys. 121, 1690 (2004)], and in this paper, we extend and elaborate upon the previous work in several important ways. The second paper focuses on construction and optimization of the wavelength functions, from theoretical and numerical viewpoints, and also examines their localization. This paper deals with their use in representations and eigenproblem calculations, which are extended to 15-dimensional systems. Even higher dimensionalities are possible using more sophisticated linear algebra techniques. This approach is ideally suited to rovibrational spectroscopy applications, but can be used in any context where differential equations are involved.

  1. Elaboration of station DICSI at KCSR and NT for studies on structural dynamics of biological objects

    Energy Technology Data Exchange (ETDEWEB)

    Korneev, V.N. [Institute of Cell Biophysics, RAS, 142290 Pushchino (Russian Federation)]. E-mail: korneev@icb.psn.ru; Shlektarev, V.A. [Institute of Theoretical and Experimental Biophysics, RAS, Institutskaya ul. 3, 142290 Pushchino (Russian Federation); Zabelin, A.V. [FSI, RRC ' Kurchatov Institute' , 123182 Moscow (Russian Federation); Medvedev, B.I. [Institute of Theoretical and Experimental Biophysics, RAS, Institutskaya ul. 3, 142290 Pushchino (Russian Federation); Sharafutdinov, M.R. [Institute of Solid State Chemistry and Mechanochemistry of SB, RAS, 630090 Novosibirsk (Russian Federation); Tolochko, V.P. [Institute of Solid State Chemistry and Mechanochemistry of SB, RAS, 630090 Novosibirsk (Russian Federation); Sheromov, M.A. [Budker Institute of Nuclear Physics of SB RAS, 630090 Novosibirsk (Russian Federation); Kondratyev, V.I. [Budker Institute of Nuclear Physics of SB RAS, 630090 Novosibirsk (Russian Federation); Umnov, A.I. [Institute of Cell Biophysics, RAS, 142290 Pushchino (Russian Federation); Vazina, A.A. [Institute of Theoretical and Experimental Biophysics, RAS, Institutskaya ul. 3, 142290 Pushchino (Russian Federation)

    2007-05-21

    In this article, the results of the experimental and theoretical developments for equipping the station 'DICSI', created on channel K1.3 (a) of the (Siberia-2) storage ring of the Kurchatov Centre for Synchrotron Radiation and Nanotechnology are considered. Argumentation for the basic parameters of the X-ray optical systems is given, photos and the schemes of created equipments are presented, in addition, the results of the test experiments with the biological objects are considered.

  2. A Chemical and Dynamical Link Between Red Centaur Objects and the Cold Classical Kuiper Belt

    Science.gov (United States)

    Tegler, Stephen C.; Romanishin, William; Consolmagno, Guy

    2015-11-01

    We present new B-V, V-R, and B-R colors for 32 Centaurs objects using the 4.3-meter Discovery Channel Telescope (DCT) near Happy Jack, AZ and the 1.8-meter Vatican Advanced Technology Telescope on Mt. Graham, AZ. Combining these new colors with our previously reported colors, we now have optical broad-band colors for 58 Centaur objects.Application of the non-parametric Dip Test to our previous sample of only 26 objects showed Centaurs split into gray and red groups at the 99.5% confidence level, and application of the Wilcoxon Rank Sum Test to the same sample showed that red Centaurs have a higher median albedo than gray Centaurs at the 99% confidence level (Tegler et al., 2008, Solar System Beyond Neptune, U Arizona Press, pp. 105-114).Here we report application of the Wilcoxon Rank Sum Test to our sample of 58 Centaurs. We confirm red Centaurs have a higher median albedo than gray Centaurs at the 99.7% level. In addition, we find that red Centaurs have a lower median inclination angle than gray Centaurs at the 99.5% confidence level. Because of their red colors and lower inclination angles, we suggest red Centaurs originate in the cold classical Kuiper belt. We thank the NASA Solar System Observations Program for its support.

  3. Moment graphs and representations

    DEFF Research Database (Denmark)

    Jantzen, Jens Carsten

    2012-01-01

    Moment graphs and sheaves on moment graphs are basically combinatorial objects that have be used to describe equivariant intersectiion cohomology. In these lectures we are going to show that they can be used to provide a direct link from this cohomology to the representation theory of simple Lie...

  4. Moment graphs and representations

    DEFF Research Database (Denmark)

    Jantzen, Jens Carsten

    2012-01-01

    Moment graphs and sheaves on moment graphs are basically combinatorial objects that have be used to describe equivariant intersectiion cohomology. In these lectures we are going to show that they can be used to provide a direct link from this cohomology to the representation theory of simple Lie...... algebras and of simple algebraic groups. The first section contains some background on equivariant cohomology....

  5. Dynamic dune management, integrating objectives of nature development and coastal safety: Examples from the Netherlands

    Science.gov (United States)

    Arens, Sebastiaan M.; Mulder, Jan P. M.; Slings, Quirinus L.; Geelen, Luc H. W. T.; Damsma, Petra

    2013-10-01

    This paper discusses and compares results of management interventions to remobilise dunes and obtain more autonomous changes in foredunes resulting from a change in coastal defence policy. In recent decades, nature conservation managers tried to restore aeolian dynamics and dune mobility landward of foredunes to maintain threatened, rare pioneer species. Results indicate that destabilisation activities yielded an important increase of blowing sand and its effects on ecology but with a limited effect on the desired integral remobilization of dunes. Roots remaining in the sand after removal of vegetation and soil is one of the main problems. Follow up removal of roots for 3 to 5 years seems to be essential, but it is not clear whether the dunes will remain mobile in the long term. In 1990 the Dutch government decided to maintain the position of the coastline by artificial sand nourishment. An intensive management of the foredunes was no longer required. Consequently, natural processes in the foredunes revived, and the sediment budget of the beach-dune system changed. Two main types of responses are visible. In some areas, increased input of sand resulted in the development of embryonic dunes seaward of the former foredunes, leading to increased stabilisation of the former foredunes. In other areas, development of embryonic dunes was insignificant despite the increased sand input, but wind erosion features developed in the foredunes, and the environment was more dynamic. The reasons for the differences are not clear, and the interaction between shoreface, beach and dunes is still poorly understood. Until now, attempts to mobilise the inner dunes were independent of changes made to the foredunes. We argue that an integrated, dynamic approach to coastal management, taking account of all relevant functions (including safety and natural values) and the dune-beach system as a whole, may provide new and durable solutions. An integrated approach would ideally provide fresh

  6. The dynamics of Neptune Trojans - II. Eccentric orbits and observed objects

    Science.gov (United States)

    Zhou, Li-Yong; Dvorak, Rudolf; Sun, Yi-Sui

    2011-01-01

    In a previous paper, we presented a global view of the stability of Neptune Trojans (NTs hereafter) on inclined orbits. As the continuation of the investigation, we discuss in this paper the dependence of the stability of NT orbits on the eccentricity. For this task, high-resolution dynamical maps are constructed using the results of extensive numerical integrations of orbits initialized on fine grids of initial semimajor axis (a0) versus eccentricity (e0). The extensions of regions of stable orbits on the (a0, e0) plane at different inclinations are shown. The maximum eccentricities of stable orbits in the three most stable regions at low (0°, 12°), medium (22°, 36°) and high (51°, 59°) inclination are found to be 0.10, 0.12 and 0.04, respectively. The fine structures in the dynamical maps are described. Via the frequency-analysis method, the mechanisms that portray the dynamical maps are revealed. The secondary resonances, at the frequency of the librating resonant angle λ-λ8 and the frequency of the quasi 2:1 mean-motion resonance (MMR hereafter) between Neptune and Uranus, are found to be deeply involved in the motion of NTs. Secular resonances are detected and they also contribute significantly to the triggering of chaos in the motion. In particular, the effects of the secular resonance ν8, ν18 are clarified. We also investigate the orbital stabilities of six observed NTs by checking the orbits of hundreds of clones generated within the observing error bars. We conclude that four of them are deeply inside the stable region, with 2001 QR322 and 2005 TO74 being the exceptions. 2001 QR322 is in the close vicinity of the most significant secondary resonance. 2005 TO74 is located close to the boundary separating stable orbits from unstable ones, and it may be influenced by a secular resonance. This article was published online on 2010 October 25. Some errors were subsequently identified. This notice is included in the online and print versions to indicate

  7. 在线低秩表示的目标跟踪算法%Object tracking via online low rank representation

    Institute of Scientific and Technical Information of China (English)

    王海军; 葛红娟; 张圣燕

    2016-01-01

    针对传统的基于生成模式的跟踪方法对噪声及遮挡问题比较敏感,导致跟踪结果失败的问题,提出了以前几帧的跟踪结果作为观测矩阵,采用鲁棒的主元成分分析模型求解观测模型的低秩特征。当新的视频流到来时,不是把所有的跟踪结果矩阵作为观测矩阵。并提出了新的增量鲁棒的主元成分分析模型,采用增广拉格朗日算法求解新矩阵的低秩特征,并以此低秩矩阵在贝叶斯框架下建立跟踪模型,用恢复的低秩特征更新字典矩阵。将文中方法与其他6种跟踪算法在8种跟踪视频上进行跟踪对比。实验结果表明,所提出的方法具有较低的像素中心位置误差和较高的重叠率。%Object tracking is an active research topic in computer vision . The traditional tracking methods based on the generative model are sensitive to noise and occlusion , which leads to the failure of tracking results . In order to solve this problem , the tracking results of the first few frames are used as the observation matrix , and the low rank features of the observation model are solved by the the RPCA model . When the new video streams come , a new incremental RPCA is proposed to compute the new observation matrix by the augmented Lagrangian algorithm . The tracking model is established in the Bayesian framework , and the dictionary matrix is updated with the low rank feature . We have tested the proposed algorithm and six state‐of‐the‐art approaches on eight publicly available sequences . Experimental results show that the proposed method has a lower pixel center position error and a higher overlap ratio .

  8. Limitless capacity: A dynamic object-oriented approach to short-term memory

    Directory of Open Access Journals (Sweden)

    Bill eMacken

    2015-03-01

    Full Text Available The notion of capacity-limited processing systems is a core element of cognitive accounts of limited and variable performance, enshrined within the short-term memory construct. We begin with a detailed critical analysis of the conceptual bases of this view and argue that there are fundamental problems – ones that go to the heart of cognitivism more generally – that render it untenable. In place of limited capacity systems, we propose a framework for explaining performance that focuses on the dynamic interplay of three aspects of any given setting: the particular task that must be accomplished, the nature and form of the material upon which the task must be performed, and the repertoire of skills and perceptual-motor functions possessed by the participant. We provide empirical examples of the applications of this framework in areas of performance typically accounted for by reference to capacity-limited short-term memory processes.

  9. Limitless capacity: a dynamic object-oriented approach to short-term memory.

    Science.gov (United States)

    Macken, Bill; Taylor, John; Jones, Dylan

    2015-01-01

    The notion of capacity-limited processing systems is a core element of cognitive accounts of limited and variable performance, enshrined within the short-term memory construct. We begin with a detailed critical analysis of the conceptual bases of this view and argue that there are fundamental problems - ones that go to the heart of cognitivism more generally - that render it untenable. In place of limited capacity systems, we propose a framework for explaining performance that focuses on the dynamic interplay of three aspects of any given setting: the particular task that must be accomplished, the nature and form of the material upon which the task must be performed, and the repertoire of skills and perceptual-motor functions possessed by the participant. We provide empirical examples of the applications of this framework in areas of performance typically accounted for by reference to capacity-limited short-term memory processes.

  10. Quiver representations

    CERN Document Server

    Schiffler, Ralf

    2014-01-01

    This book is intended to serve as a textbook for a course in Representation Theory of Algebras at the beginning graduate level. The text has two parts. In Part I, the theory is studied in an elementary way using quivers and their representations. This is a very hands-on approach and requires only basic knowledge of linear algebra. The main tool for describing the representation theory of a finite-dimensional algebra is its Auslander-Reiten quiver, and the text introduces these quivers as early as possible. Part II then uses the language of algebras and modules to build on the material developed before. The equivalence of the two approaches is proved in the text. The last chapter gives a proof of Gabriel’s Theorem. The language of category theory is developed along the way as needed.

  11. Dynamically Excited Outer Solar System Objects in the Hubble Space Telescope Archive

    CERN Document Server

    Fuentes, Cesar I; Holman, Matthew J

    2011-01-01

    We present the faintest mid ecliptic latitude survey in the second part of HST archival search for outer Solar System bodies. We report the discovery of 28 new trans-Neptunian objects and 1 small centaur (R ~ 2km) in the band 5{\\circ} - 20{\\circ} off the ecliptic. The inclination distribution of these excited ob jects is consistent with the distribution derived from brighter ecliptic surveys. We suggest that the size and inclination distribution should be estimated consistently using suitable surveys with calibrated search algorithms and reliable orbital information.

  12. Poetic representation

    DEFF Research Database (Denmark)

    Wulf-Andersen, Trine Østergaard

    2012-01-01

    This article is based on a Danish research project with young people in vulnerable positions. Young people are involved throughout the research process, including the interpretation of material produced through interviews, and discussions on how reflections and conclusions from the research should......, and dialogue, of situated participants. The article includes a lengthy example of a poetic representation of one participant’s story, and the author comments on the potentials of ‘doing’ poetic representations as an example of writing in ways that challenges what sometimes goes unasked in participative social...

  13. Value Representations

    DEFF Research Database (Denmark)

    Rasmussen, Majken Kirkegaard; Petersen, Marianne Graves

    2011-01-01

    Stereotypic presumptions about gender affect the design process, both in relation to how users are understood and how products are designed. As a way to decrease the influence of stereotypic presumptions in design process, we propose not to disregard the aspect of gender in the design process......, as the perspective brings valuable insights on different approaches to technology, but instead to view gender through a value lens. Contributing to this perspective, we have developed Value Representations as a design-oriented instrument for staging a reflective dialogue with users. Value Representations...

  14. The DTW-based representation space for seismic pattern classification

    Science.gov (United States)

    Orozco-Alzate, Mauricio; Castro-Cabrera, Paola Alexandra; Bicego, Manuele; Londoño-Bonilla, John Makario

    2015-12-01

    Distinguishing among the different seismic volcanic patterns is still one of the most important and labor-intensive tasks for volcano monitoring. This task could be lightened and made free from subjective bias by using automatic classification techniques. In this context, a core but often overlooked issue is the choice of an appropriate representation of the data to be classified. Recently, it has been suggested that using a relative representation (i.e. proximities, namely dissimilarities on pairs of objects) instead of an absolute one (i.e. features, namely measurements on single objects) is advantageous to exploit the relational information contained in the dissimilarities to derive highly discriminant vector spaces, where any classifier can be used. According to that motivation, this paper investigates the suitability of a dynamic time warping (DTW) dissimilarity-based vector representation for the classification of seismic patterns. Results show the usefulness of such a representation in the seismic pattern classification scenario, including analyses of potential benefits from recent advances in the dissimilarity-based paradigm such as the proper selection of representation sets and the combination of different dissimilarity representations that might be available for the same data.

  15. Accurately characterizing the importance of wave‐particle interactions in radiation belt dynamics: The pitfalls of statistical wave representations

    Science.gov (United States)

    Mann, Ian R.; Rae, I. Jonathan; Sibeck, David G.; Watt, Clare E. J.

    2016-01-01

    Abstract Wave‐particle interactions play a crucial role in energetic particle dynamics in the Earth's radiation belts. However, the relative importance of different wave modes in these dynamics is poorly understood. Typically, this is assessed during geomagnetic storms using statistically averaged empirical wave models as a function of geomagnetic activity in advanced radiation belt simulations. However, statistical averages poorly characterize extreme events such as geomagnetic storms in that storm‐time ultralow frequency wave power is typically larger than that derived over a solar cycle and Kp is a poor proxy for storm‐time wave power. PMID:27867798

  16. Accurately characterizing the importance of wave-particle interactions in radiation belt dynamics: The pitfalls of statistical wave representations.

    Science.gov (United States)

    Murphy, Kyle R; Mann, Ian R; Rae, I Jonathan; Sibeck, David G; Watt, Clare E J

    2016-08-01

    Wave-particle interactions play a crucial role in energetic particle dynamics in the Earth's radiation belts. However, the relative importance of different wave modes in these dynamics is poorly understood. Typically, this is assessed during geomagnetic storms using statistically averaged empirical wave models as a function of geomagnetic activity in advanced radiation belt simulations. However, statistical averages poorly characterize extreme events such as geomagnetic storms in that storm-time ultralow frequency wave power is typically larger than that derived over a solar cycle and Kp is a poor proxy for storm-time wave power.

  17. A Model of the Dynamic Error as a Measurement Result of Instruments Defining the Parameters of Moving Objects

    Science.gov (United States)

    Dichev, D.; Koev, H.; Bakalova, T.; Louda, P.

    2014-08-01

    The present paper considers a new model for the formation of the dynamic error inertial component. It is very effective in the analysis and synthesis of measuring instruments positioned on moving objects and measuring their movement parameters. The block diagram developed within this paper is used as a basis for defining the mathematical model. The block diagram is based on the set-theoretic description of the measuring system, its input and output quantities and the process of dynamic error formation. The model reflects the specific nature of the formation of the dynamic error inertial component. In addition, the model submits to the logical interrelation and sequence of the physical processes that form it. The effectiveness, usefulness and advantages of the model proposed are rooted in the wide range of possibilities it provides in relation to the analysis and synthesis of those measuring instruments, the formulation of algorithms and optimization criteria, as well as the development of new intelligent measuring systems with improved accuracy characteristics in dynamic mode.

  18. Planning and managing future space facility projects. [management by objectives and group dynamics

    Science.gov (United States)

    Sieber, J. E.; Wilhelm, J. A.; Tanner, T. A.; Helmreich, R. L.; Burgenbauch, S. F.

    1979-01-01

    To learn how ground-based personnel of a space project plan and organize their work and how such planning and organizing relate to work outcomes, longitudinal study of the management and execution of the Space Lab Mission Development Test 3 (SMD 3) was performed at NASA Ames Research Center. A view of the problems likely to arise in organizations and some methods of coping with these problems are presented as well as the conclusions and recommendations that pertain strictly to SMD 3 management. Emphasis is placed on the broader context of future space facility projects and additional problems that may be anticipated. A model of management that may be used to facilitate problem solving and communication - management by objectives (MBO) is presented. Some problems of communication and emotion management that MBO does not address directly are considered. Models for promoting mature, constructive and satisfying emotional relationships among group members are discussed.

  19. Dynamics of asteroids and near-Earth objects from Gaia Astrometry

    CERN Document Server

    Bancelin, D; Thuillot, W

    2016-01-01

    Gaia is an astrometric mission that will be launched in spring 2013. There are many scientific outcomes from this mission and as far as our Solar System is concerned, the satellite will be able to map thousands of main belt asteroids (MBAs) and near-Earth objects (NEOs) down to magnitude < 20. The high precision astrometry (0.3-5 mas of accuracy) will allow orbital improvement, mass determination, and a better accuracy in the prediction and ephemerides of potentially hazardous asteroids (PHAs). We give in this paper some simulation tests to analyse the impact of Gaia data on known asteroids' orbit, and their value for the analysis of NEOs through the example of asteroid (99942) Apophis. We then present the need for a follow-up network for newly discovered asteroids by Gaia, insisting on the synergy of ground and space data for the orbital improvement.

  20. The “May” Decrees of the President: objective, indicators, implementation dynamics

    Directory of Open Access Journals (Sweden)

    Mariya Aleksandrovna Pechenskaya

    2015-01-01

    Full Text Available Two and a half years have passed since the RF President’s adoption of a number of decrees aimed at improving social welfare of the citizens. The objectives of the given legal documents concern the issues of education and science, health, demography and social policy, economy and foreign policy, military service and development of the Armed Forces of Russia, inter-ethnic harmony, governance and quality of housing and utility services. V.V. Putin has set targets to be achieved in Russia by 2020. However, the acute budget crisis of regional systems hinders the implementation of Presidential Decrees. This article provides the reader with the analysis of the achieved results and states the problems of “May” requirements funding. In addition, there are possible options for the implementation of the targets laid down in the presidential decrees in the prescribed period

  1. Dynamic Carpooling in Urban Areas: Design and Experimentation with a Multi-Objective Route Matching Algorith

    Directory of Open Access Journals (Sweden)

    Matteo Mallus

    2017-02-01

    Full Text Available This paper focuses on dynamic carpooling services in urban areas to address the needs of mobility in real-time by proposing a two-fold contribution: a solution with novel features with respect to the current state-of-the-art, which is named CLACSOON and is available on the market; the analysis of the carpooling services performance in the urban area of the city of Cagliari through emulations. Two new features characterize the proposed solution: partial ridesharing, according to which the riders can walk to reach the driver along his/her route when driving to the destination; the possibility to share the ride when the driver has already started the ride by modelling the mobility to reach the driver destination. To analyse which features of the population bring better performance to changing the characteristics of the users, we also conducted emulations. When compared with current solutions, CLACSOON allows for achieving a decrease in the waiting time of around 55% and an increase in the driver and passenger success rates of around 4% and 10%,respectively. Additionally, the proposed features allowed for having an increase in the reduction of the CO2 emission by more than 10% with respect to the traditional carpooling service.

  2. Studying Dynamic Processes of Nano-sized Objects in Liquid using Scanning Transmission Electron Microscopy.

    Science.gov (United States)

    Hermannsdörfer, Justus; de Jonge, Niels

    2017-02-05

    Samples fully embedded in liquid can be studied at a nanoscale spatial resolution with Scanning Transmission Electron Microscopy (STEM) using a microfluidic chamber assembled in the specimen holder for Transmission Electron Microscopy (TEM) and STEM. The microfluidic system consists of two silicon microchips supporting thin Silicon Nitride (SiN) membrane windows. This article describes the basic steps of sample loading and data acquisition. Most important of all is to ensure that the liquid compartment is correctly assembled, thus providing a thin liquid layer and a vacuum seal. This protocol also includes a number of tests necessary to perform during sample loading in order to ensure correct assembly. Once the sample is loaded in the electron microscope, the liquid thickness needs to be measured. Incorrect assembly may result in a too-thick liquid, while a too-thin liquid may indicate the absence of liquid, such as when a bubble is formed. Finally, the protocol explains how images are taken and how dynamic processes can be studied. A sample containing AuNPs is imaged both in pure water and in saline.

  3. Tracking and imaging of dynamic objects in scattering media by time-reversed adapted-perturbation (TRAP) optical focusing

    CERN Document Server

    Ma, Cheng; Liu, Yan; Wang, Lihong V

    2014-01-01

    The ability to steer light propagation inside scattering media has long been sought-after due to its potential widespread applications. To form optical foci inside scattering media, the only feasible strategy is to guide photons by using either implanted or virtual guide stars. However, all of these guide stars must be introduced extrinsically, either invasively or by physical contact, limiting the scope of their application. Here, we focus light inside scattering media by employing intrinsic dynamics as guide stars. By time-reversing the perturbed component of the scattered light adaptively, we concentrate light to the origin of the perturbation, where the permittivity varied spontaneously. We demonstrate dynamic light focusing onto moving targets and imaging of a time-variant object obscured by highly scattering media, without invasiveness and physical contact. Anticipated applications include all-weather optical communication with airplanes or satellites, tracking vehicles in thick fogs, and imaging and ph...

  4. Political representation and its mechanisms: a dynamic left-right approach for the United Kingdom, 1976-2006

    NARCIS (Netherlands)

    A. Hakhverdian

    2010-01-01

    Some scholars use the ‘dynamic representation’ approach to test how much current policy changes reflect past public preferences. This article tests hypotheses derived from this approach in a left-right context for the United Kingdom from 1976 to 2006. This shows that government policy on the left-ri

  5. Representational Machines

    DEFF Research Database (Denmark)

    Petersson, Dag; Dahlgren, Anna; Vestberg, Nina Lager

    to the enterprises of the medium. This is the subject of Representational Machines: How photography enlists the workings of institutional technologies in search of establishing new iconic and social spaces. Together, the contributions to this edited volume span historical epochs, social environments, technological...

  6. Towards Multimodal Content Representation

    CERN Document Server

    Bunt, Harry

    2009-01-01

    Multimodal interfaces, combining the use of speech, graphics, gestures, and facial expressions in input and output, promise to provide new possibilities to deal with information in more effective and efficient ways, supporting for instance: - the understanding of possibly imprecise, partial or ambiguous multimodal input; - the generation of coordinated, cohesive, and coherent multimodal presentations; - the management of multimodal interaction (e.g., task completion, adapting the interface, error prevention) by representing and exploiting models of the user, the domain, the task, the interactive context, and the media (e.g. text, audio, video). The present document is intended to support the discussion on multimodal content representation, its possible objectives and basic constraints, and how the definition of a generic representation framework for multimodal content representation may be approached. It takes into account the results of the Dagstuhl workshop, in particular those of the informal working group...

  7. Decoherence-governed magnetic-moment dynamics of supported atomic objects

    Science.gov (United States)

    Gauyacq, Jean-Pierre; Lorente, Nicolás

    2015-11-01

    Due to the quantum evolution of molecular magnetic moments, the magnetic state of nanomagnets can suffer spontaneous changes. This process can be completely quenched by environment-induced decoherence. However, we show that for typical small supported atomic objects, the substrate-induced decoherence does change the magnetic-moment evolution but does not quell it. To be specific and to compare with experiment, we analyze the spontaneous switching between two equivalent magnetization states of atomic structures formed by Fe on Cu2N/Cu (1 0 0), measured by Loth et al (2012 Science 335 196-9). Due to the substrate-induced decoherence, the Rabi oscillations proper to quantum tunneling between magnetic states are replaced by an irreversible decay of long characteristic times leading to the observed stochastic magnetization switching. We show that the corresponding switching rates are small, rapidly decreasing with system’s size, with a 1/T thermal behavior and in good agreement with experiments. Quantum tunneling is recovered as the switching mechanism at extremely low temperatures below the μK range for a six-Fe-atom system and exponentially lower for larger atomic systems. The unexpected conclusion of this work is that experiments could detect the switching of these supported atomic systems because their magnetization evolution is somewhere between complete decoherence-induced stability and unobservably fast quantum-tunneling switching.

  8. Some Design-Objectives and Design-Guidelines for Automotive Friction Clutch Based on Clutch Engagement Dynamics

    Science.gov (United States)

    Tripathi, K.

    2014-01-01

    Dynamics of the driveline and the vehicle during clutch engagement is a complex phenomenon. Time domain analysis of different state variables is performed through numerical solution of sixth-order driveline model using an indigenous computer program. The study revealed that different design objectives like driver and passenger comfort, smoothness of engagement, wear of friction surfaces, power loss, and heat generation are in mutual conflict, with respect to the sub-ranges of operational parameters. The overall outcome of this study is presented in the form of a matrix, relating the sub-ranges of operational parameters with engagement quality parameters, which may be used as a guideline for clutch design for different design objectives. The engagement quality parameters may also be used for building a cost function for overall optimization of clutch.

  9. The object-oriented development of a parallel application in protein dynamics: why we need software tools for HPCN applications

    Science.gov (United States)

    Bækdal, Lars; Joosen, Wouter; Larsen, Thomas; Kolafa, Jiri; Ovesen, Jens H.; Perram, John W.; Petersen, Henrik G.; Bywater, Robert; Ratner, Mark

    1996-08-01

    We analyse the concurrency and performance of the various types of force calculations involved in the molecular dynamics simulation of large protein or polyelectrolyte molecules. Although this analysis can in principle be used to write a meta-program to optimize load-balancing of this application on an MPP system, we argue that it is an enormous undertaking not appropriate for the computational scientist. Instead we argue that it is better to exploit research in parallel execution environments which provide automatic load-balancing for concurrent Object-Oriented applications. We also argue that use of Object-Oriented technology in the design of simulation software encapsulates the natural concurrency of the system. We illustrate this point with a discussion of the constraint force calculation for a polymeric molecule.

  10. Dynamics of H{sub 2} Eley-Rideal abstraction from W(110): Sensitivity to the representation of the molecule-surface potential

    Energy Technology Data Exchange (ETDEWEB)

    Pétuya, R., E-mail: r.petuya@ism.u-bordeaux1.fr; Larrégaray, P.; Crespos, C. [Université de Bordeaux, ISM, CNRS UMR 5255, 33405 Talence Cedex (France); CNRS, ISM, UMR5255, F-33400 Talence (France); Busnengo, H. F.; Martínez, A. E. [Instituto de Física Rosario (IFIR) CONICET-UNR. Ocampo y Esmeralda (2000) Rosario (Argentina)

    2014-07-14

    Dynamics of the Eley-Rideal (ER) abstraction of H{sub 2} from W(110) is analyzed by means of quasi-classical trajectory calculations. Simulations are based on two different molecule-surface potential energy surfaces (PES) constructed from Density Functional Theory results. One PES is obtained by fitting, using a Flexible Periodic London-Eyring-Polanyi-Sato (FPLEPS) functional form, and the other by interpolation through the corrugation reducing procedure (CRP). Then, the present study allows us to elucidate the ER dynamics sensitivity on the PES representation. Despite some sizable discrepancies between both H+H/W(110) PESs, the obtained projectile-energy dependence of the total ER cross sections are qualitatively very similar ensuring that the main physical ingredients are captured in both PES models. The obtained distributions of the final energy among the different molecular degrees of freedom barely depend on the PES model, being most likely determined by the reaction exothermicity. Therefore, a reasonably good agreement with the measured final vibrational state distribution is observed in spite of the pressure and material gaps between theoretical and experimental conditions.

  11. Immediate compensation for variations in self-generated Coriolis torques related to body dynamics and carried objects.

    Science.gov (United States)

    Pigeon, Pascale; Dizio, Paul; Lackner, James R

    2013-09-01

    We have previously shown that the Coriolis torques that result when an arm movement is performed during torso rotation do not affect movement trajectory. Our purpose in the present study was to examine whether torso motion-induced Coriolis and other interaction torques are counteracted during a turn and reach (T&R) movement when the effective mass of the hand is augmented, and whether the dominant arm has an advantage in coordinating intersegmental dynamics as predicted by the dynamic dominance hypothesis (Sainburg RL. Exp Brain Res 142: 241-258, 2002). Subjects made slow and fast T&R movements in the dark to just extinguished targets with either arm, while holding or not holding a 454-g object. Movement endpoints were equally accurate at both speeds, with either hand, and in both weight conditions, but subjects tended to angularly undershoot and produce more variable endpoints for targets requiring greater torso rotation. There were no changes in endpoint accuracy or trajectory deviation over repeated movements. The dominant right arm was more stable in its control of trajectory direction across targets, whereas the nondominant left arm had an improved ability to stop accurately on the target for higher levels of interaction torques. The trajectories to more eccentric targets were straighter when performed at higher speeds but slightly more deviated when subjects held the weight. Subjects did not slow their torso velocity or change the timing of the arm and torso velocities when holding the weight, although there was a slight decrease in their hand velocity relative to the torso. The delay between the onsets of torso and finger movements was almost twice as large for the right arm than the left, suggesting the right arm was better able to account for torso rotation in the arm movement. Holding the weight increased the peak Coriolis torque by 40% at the shoulder and 45% at the elbow and, for the most eccentric target, increased the peak net torque by 12% at the

  12. An exact representation of the fermion dynamics in terms of Poisson processes and its connection with Monte Carlo algorithms

    Science.gov (United States)

    Beccaria, M.; Presilla, C.; DeAngelis, G. F.; Jona-Lasinio, G.

    1999-11-01

    We present a simple derivation of a Feynman-Kac type formula to study fermionic systems. In this approach the real time or the imaginary time dynamics is expressed in terms of the evolution of a collection of Poisson processes. This formula leads to a family of algorithms parametrized by the values of the jump rates of the Poisson processes. From these an optimal algorithm can be chosen which coincides with the Green Function Monte Carlo method in the limit when the latter becomes exact.

  13. Rotation-independent representations for haptic movements

    Science.gov (United States)

    Shioiri, Satoshi; Yamazaki, Takanori; Matsumiya, Kazumichi; Kuriki, Ichiro

    2013-01-01

    The existence of a common mechanism for visual and haptic representations has been reported in object perception. In contrast, representations of movements might be more specific to modalities. Referring to the vertical axis is natural for visual representations whereas a fixed reference axis might be inappropriate for haptic movements and thus also inappropriate for its representations in the brain. The present study found that visual and haptic movement representations are processed independently. A psychophysical experiment examining mental rotation revealed the well-known effect of rotation angle for visual representations whereas no such effect was found for haptic representations. We also found no interference between processes for visual and haptic movements in an experiment where different stimuli were presented simultaneously through visual and haptic modalities. These results strongly suggest that (1) there are separate representations of visual and haptic movements, and (2) the haptic process has a rotation-independent representation. PMID:24005481

  14. Human, Nature, Dynamism: The Effects of Content and Movement Perception on Brain Activations during the Aesthetic Judgment of Representational Paintings.

    Science.gov (United States)

    Di Dio, Cinzia; Ardizzi, Martina; Massaro, Davide; Di Cesare, Giuseppe; Gilli, Gabriella; Marchetti, Antonella; Gallese, Vittorio

    2015-01-01

    Movement perception and its role in aesthetic experience have been often studied, within empirical aesthetics, in relation to the human body. No such specificity has been defined in neuroimaging studies with respect to contents lacking a human form. The aim of this work was to explore, through functional magnetic imaging (f MRI), how perceived movement is processed during the aesthetic judgment of paintings using two types of content: human subjects and scenes of nature. Participants, untutored in the arts, were shown the stimuli and asked to make aesthetic judgments. Additionally, they were instructed to observe the paintings and to rate their perceived movement in separate blocks. Observation highlighted spontaneous processes associated with aesthetic experience, whereas movement judgment outlined activations specifically related to movement processing. The ratings recorded during aesthetic judgment revealed that nature scenes received higher scored than human content paintings. The imaging data showed similar activation, relative to baseline, for all stimuli in the three tasks, including activation of occipito-temporal areas, posterior parietal, and premotor cortices. Contrast analyses within aesthetic judgment task showed that human content activated, relative to nature, precuneus, fusiform gyrus, and posterior temporal areas, whose activation was prominent for dynamic human paintings. In contrast, nature scenes activated, relative to human stimuli, occipital and posterior parietal cortex/precuneus, involved in visuospatial exploration and pragmatic coding of movement, as well as central insula. Static nature paintings further activated, relative to dynamic nature stimuli, central and posterior insula. Besides insular activation, which was specific for aesthetic judgment, we found a large overlap in the activation pattern characterizing each stimulus dimension (content and dynamism) across observation, aesthetic judgment, and movement judgment tasks. These

  15. A review of a method for dynamic load distribution, dynamical modeling, and explicit internal force control when two manipulators mutually lift and transport a rigid body object

    Energy Technology Data Exchange (ETDEWEB)

    Unseren, M.A.

    1997-04-20

    The paper reviews a method for modeling and controlling two serial link manipulators which mutually lift and transport a rigid body object in a three dimensional workspace. A new vector variable is introduced which parameterizes the internal contact force controlled degrees of freedom. A technique for dynamically distributing the payload between the manipulators is suggested which yields a family of solutions for the contact forces and torques the manipulators impart to the object. A set of rigid body kinematic constraints which restrict the values of the joint velocities of both manipulators is derived. A rigid body dynamical model for the closed chain system is first developed in the joint space. The model is obtained by generalizing the previous methods for deriving the model. The joint velocity and acceleration variables in the model are expressed in terms of independent pseudovariables. The pseudospace model is transformed to obtain reduced order equations of motion and a separate set of equations governing the internal components of the contact forces and torques. A theoretic control architecture is suggested which explicitly decouples the two sets of equations comprising the model. The controller enables the designer to develop independent, non-interacting control laws for the position control and internal force control of the system.

  16. Measurement of dynamical paths from elastic objects at the entrainment frequencies using high speed digital holographic interferometry

    Science.gov (United States)

    López, Carlos Pérez; Santoyo, Fernando Mendoza

    2012-06-01

    Digital holographic interferometry (DHI) is a powerful tool to study the mechanical evolution of vibrating objects. Data obtained from interferometric fringe patterns render results with high spatial resolution amplitudes of the order of few micrometers to sub micrometers. Modern cameras with high speed frame acquisition enable the measurement of several samples of the evolving amplitude within a complete mechanical oscillation period, allowing the study of the temporal mechanical evolution as well. An interesting phenomenon which may be observed and studied with DHI is that of frequency entrainment, a feature that appears in some elastic objects. If a periodic mechanical force of frequency ω is applied to a flat rectangular elastic membrane clamped at its edges, produces a resonant frequency ωR that has a limit cycle, but as the difference between the two frequencies decreases the object frequency falls in synchronicity with the forcing frequency within a certain band of frequencies. In this paper we describe the full field of view experiments to measure these dynamical paths that are forced to oscillate near the resonant frequency where the entrainment is reached. We also discuss the possibility of using these paths as a form of generating spatio-temporal patterns for mathematical biological models simulations, a key subject in the biomedical area.

  17. Searching for Appropriate Data and Parameters for Effective Representation of Ionospheric Dynamics; Modelling and Observational Results over the African Sector

    Science.gov (United States)

    Habarulema, J. B.; Katamzi, Z. T.; McKinnell, L. A.; Tshimangadzo, M.

    2014-12-01

    We report on the ongoing efforts of modelling and characterising the ionospheric dynamics over the African sector. We have investigated the usage of a combination of data sources (GPS, ionosonde, radio occultation) along with other geophysical parameters such as magnetic and solar activities to generate realistic ionospheric behaviour for both scientific understanding and application purposes. However a number of outstanding questions remain such as capturing all storm phases, and accurate validation of some data sources. This is in addition to complicated electrodynamics over the African sector coupled with significant data-gaps that hinder the development of truly representative modelling approaches. Our ultimate aim is to develop a model that can be used for accurately representing the ionospheric behaviour and can be utilised as a space weather product for application purposes. In this presentation, the current modelling options under investigation for ionospheric modelling and mapping over the African sector will be discussed.

  18. Web portal for dynamic creation and publication of teaching materials in multiple formats from a single source representation

    Science.gov (United States)

    Roganov, E. A.; Roganova, N. A.; Aleksandrov, A. I.; Ukolova, A. V.

    2017-01-01

    We implement a web portal which dynamically creates documents in more than 30 different formats including html, pdf and docx from a single original material source. It is obtained by using a number of free software such as Markdown (markup language), Pandoc (document converter), MathJax (library to display mathematical notation in web browsers), framework Ruby on Rails. The portal enables the creation of documents with a high quality visualization of mathematical formulas, is compatible with a mobile device and allows one to search documents by text or formula fragments. Moreover, it gives professors the ability to develop the latest technology educational materials, without qualified technicians' assistance, thus improving the quality of the whole educational process.

  19. Non-resonant secular dynamics of trans-Neptunian objects perturbed by a distant super-Earth

    Science.gov (United States)

    Saillenfest, Melaine; Fouchard, Marc; Tommei, Giacomo; Valsecchi, Giovanni B.

    2017-08-01

    We use a secular model to describe the non-resonant dynamics of trans-Neptunian objects in the presence of an external ten-Earth-mass perturber. The secular dynamics is analogous to an "eccentric Kozai mechanism" but with both an inner component (the four giant planets) and an outer one (the eccentric distant perturber). By the means of Poincaré sections, the cases of a non-inclined or inclined outer planet are successively studied, making the connection with previous works. In the inclined case, the problem is reduced to two degrees of freedom by assuming a non-precessing argument of perihelion for the perturbing body. The size of the perturbation is typically ruled by the semi-major axis of the small body: we show that the classic integrable picture is still valid below about 70 AU, but it is progressively destroyed when we get closer to the external perturber. In particular, for a>150 AU, large-amplitude orbital flips become possible, and for a>200 AU, the Kozai libration islands at ω =π /2 and 3π /2 are totally submerged by the chaotic sea. Numerous resonance relations are highlighted. The most large and persistent ones are associated with apsidal alignments or anti-alignments with the orbit of the distant perturber.

  20. Instability of political preferences and the role of mass media: a dynamical representation in a quantum framework.

    Science.gov (United States)

    Khrennikova, Polina; Haven, Emmanuel

    2016-01-13

    We search to devise a new paradigm borrowed from concepts and mathematical tools of quantum physics, to model the decision-making process of the US electorate. The statistical data of the election outcomes in the period between 2008 and 2014 is analysed, in order to explore in more depth the emergence of the so-called divided government. There is an increasing urge in the political literature which indicates that preference reversal (strictly speaking the violation of the transitivity axiom) is a consequence of the so-called non-separability phenomenon (i.e. a strong interrelation of choices). In the political science literature, non-separable behaviour is characterized by a conditioning of decisions on the outcomes of some issues of interest. An additional source of preference reversal is ascribed to the time dynamics of the voters' cognitive states, in the context of new upcoming political information. As we discuss in this paper, the primary source of political information can be attributed to the mass media. In order to shed more light on the phenomenon of preference reversal among the US electorate, we accommodate the obtained statistical data in a classical probabilistic (Kolmogorovian) scheme. Based on the obtained results, we attribute the strong ties between the voters non-separable decisions that cannot be explained by conditioning with the Bayes scheme, to the quantum phenomenon of entanglement. Second, we compute the degree of interference of voters' belief states with the aid of the quantum analogue of the formula of total probability. Lastly, a model, based on the quantum master equation, to incorporate the impact of the mass media bath is proposed.

  1. Artificial Intelligence's Fusing Representation Model Based on Dynamics of Neural System%人工智能的神经系统动力学融合表示模型研究

    Institute of Scientific and Technical Information of China (English)

    危辉

    2003-01-01

    The problem of representation is the most kernel and most key problem in artificial intelligence. The hy-pothesis of inconsequence of the lower order structure is our traditional choice, and use standing instead of standingfor to implement representation. Stemming from computational cognitive neuroscience, thus based on neuron infor-mation processing, massive representation by neural network and cognitive behaviors' dynamics model of neural sys-tem, this research aims to build a common and consistent groundwork within neuroscience to explain kinds of intelli-gent behaviors, and fuse indormation, system and processing procedure together fluently. This research is great sig-nificant for the structure simulation method of AI and the probe of intelligence's neural mechanism.

  2. Evaluating Effect of Objectives, Obstacles, Drivers, Team Dynamics and Organizational Support on ICT Effectiveness by Fuzzy DEMATEL

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Keramati

    2012-12-01

    Full Text Available Due to different effects of ICT on varied aspects of performing the duties in organizations, governments have been intending to use ICT in the recent years very dramatically. The significant issue to which we should pay attention is the using of ICT without directing attention towards the mutual effects of different ICT domains shall be resulted in malfunction and inefficiency of organizations in carrying out their tasks. Therefore, the present research tried to develop a systematic structure in ICT domain and analyze the various ICT domains in order to identify the penetrating and penetrated factors (cause and effect. In doing so, at the present research firstly by the usage of other researchers' results and achievements, it was attempted to specify the different ICT domains including objectives, obstacles, drivers, team dynamics and organizational support and then another elements so-called ICT effectiveness was added in order to study the effect of above-mentioned factors on ICT effectiveness. Then, standard fuzzy DEMATEL technique questionnaire was distributed among 35 persons of experts working in ICT and IT fields to gather required information and data. After gathering required data and information, they were analyzed through DEMATEL techniques in fuzzy states, respectively. The results obtained from the DEMATEL technique in fuzzy state reveal that in ICT domain, the objectives were determined as the most penetrating elements into other elements of ICT domain and the drivers were the most penetrable element in ICT domain too.

  3. High-sensitivity and cost-effective system for infrared imaging of concealed objects in dynamic mode

    Science.gov (United States)

    Gordiyenko, E.; Yefremenko, V.; Pearson, J.; Bader, S. D.; Novosad, V.

    2005-05-01

    Novel, cost-efficient, and highly-sensitive IR imaging systems play an important role in homeland security functions. Technical limitations in the areas of sensitivity, contrast ratio, bandwidth and cost continue to constrain imaging capabilities. We have designed and prototyped a compact computer-piloted high sensitivity infrared imaging system. The device consists of infrared optics, cryostat, low-noise pre-amplifier, Analog-to-Digital hardware, feedback electronics, and unique image processing software. Important advantages of the developed system are: (i) Eight electronic channels are available for simultaneous registration of IR and visible images in multiple spectral ranges, (ii) Capability of real-time analysis such as comparing the "sensed" image with "reference" images from a database, (iii) High accuracy temperature measurement of multiple points on the image by referencing the radiation intensity from the object to a black body model, (iv) Image generation by real-time integration of images from multiple sensors operating from the visible to the terahertz range. The device was tested with a liquid-nitrogen-cooled, single-pixel HgCdTe detector for imaging in 8-12 microns range. The demonstrated examples of infrared imaging of concealed objects in static and dynamic modes include a hammer (metal head and wooden handle), plastic imitator of handguns hidden under clothes, powder in an envelope, and revealing complex wall structures under decorative plaster.

  4. Unsupervised change detection in VHR remote sensing imagery - an object-based clustering approach in a dynamic urban environment

    Science.gov (United States)

    Leichtle, Tobias; Geiß, Christian; Wurm, Michael; Lakes, Tobia; Taubenböck, Hannes

    2017-02-01

    Monitoring of changes is one of the most important inherent capabilities of remote sensing. The steadily increasing amount of available very-high resolution (VHR) remote sensing imagery requires highly automatic methods and thus, largely unsupervised concepts for change detection. In addition, new procedures that address this challenge should be capable of handling remote sensing data acquired by different sensors. Thereby, especially in rapidly changing complex urban environments, the high level of detail present in VHR data indicates the deployment of object-based concepts for change detection. This paper presents a novel object-based approach for unsupervised change detection with focus on individual buildings. First, a principal component analysis together with a unique procedure for determination of the number of relevant principal components is performed as a predecessor for change detection. Second, k-means clustering is applied for discrimination of changed and unchanged buildings. In this manner, several groups of object-based difference features that can be derived from multi-temporal VHR data are evaluated regarding their discriminative properties for change detection. In addition, the influence of deviating viewing geometries when using VHR data acquired by different sensors is quantified. Overall, the proposed workflow returned viable results in the order of κ statistics of 0.8-0.9 and beyond for different groups of features, which demonstrates its suitability for unsupervised change detection in dynamic urban environments. With respect to imagery from different sensors, deviating viewing geometries were found to deteriorate the change detection result only slightly in the order of up to 0.04 according to κ statistics, which underlines the robustness of the proposed approach.

  5. Thinking together with material representations

    DEFF Research Database (Denmark)

    Stege Bjørndahl, Johanne; Fusaroli, Riccardo; Østergaard, Svend

    2014-01-01

    How do material representations such as models, diagrams and drawings come to shape and aid collective, epistemic processes? This study investigated how groups of participants spontaneously recruited material objects (in this case LEGO blocks) to support collective creative processes in the context......, the material representations were experimented on and physical attributes were explored resulting in discoveries of new meaning potentials and creative solutions. We discuss these different ways in which material representations do their work in collective reasoning processes in relation to ideas about top...

  6. Octree Representation and Its Applications in CAD

    Institute of Scientific and Technical Information of China (English)

    唐泽圣

    1992-01-01

    In this paper,a survey of octree representation and its applications in CAD is presented.The octree representation may be categorized as pure octree representation and polytree(or extended octree),and the latter is actually a boundary representation decomposed by octree.Linear octree which is a variant of regular octree representation has the advantage of saving memory space.The mapping between Cartesian coordinates and node addresses in linear octree is discussed.Then,algorithms for converting a boundary representation of 3D object into an octree are investiged and major approaches for transforming an octree encoded object are presented.After that,some of the applications of octree representation in CAD are listed,in particular,the applications in solid modeling,in accelerating ray tracing and in generating meshes for FEM.

  7. The Achievement of Therapeutic Objectives Scale: Interrater Reliability and Sensitivity to Change in Short-Term Dynamic Psychotherapy and Cognitive Therapy

    Science.gov (United States)

    Valen, Jakob; Ryum, Truls; Svartberg, Martin; Stiles, Tore C.; McCullough, Leigh

    2011-01-01

    This study examined interrater reliability and sensitivity to change of the Achievement of Therapeutic Objectives Scale (ATOS; McCullough, Larsen, et al., 2003) in short-term dynamic psychotherapy (STDP) and cognitive therapy (CT). The ATOS is a process scale originally developed to assess patients' achievements of treatment objectives in STDP,…

  8. Representation and Re-Presentation in Litigation Science

    Science.gov (United States)

    Jasanoff, Sheila

    2008-01-01

    Federal appellate courts have devised several criteria to help judges distinguish between reliable and unreliable scientific evidence. The best known are the U.S. Supreme Court’s criteria offered in 1993 in Daubert v. Merrell Dow Pharmaceuticals, Inc. This article focuses on another criterion, offered by the Ninth Circuit Court of Appeals, that instructs judges to assign lower credibility to “litigation science” than to science generated before litigation. In this article I argue that the criterion-based approach to judicial screening of scientific evidence is deeply flawed. That approach buys into the faulty premise that there are external criteria, lying outside the legal process, by which judges can distinguish between good and bad science. It erroneously assumes that judges can ascertain the appropriate criteria and objectively apply them to challenged evidence before litigation unfolds, and before methodological disputes are sorted out during that process. Judicial screening does not take into account the dynamics of litigation itself, including gaming by the parties and framing by judges, as constitutive factors in the production and representation of knowledge. What is admitted through judicial screening, in other words, is not precisely what a jury would see anyway. Courts are sites of repeated re-representations of scientific knowledge. In sum, the screening approach fails to take account of the wealth of existing scholarship on the production and validation of scientific facts. An unreflective application of that approach thus puts courts at risk of relying upon a “junk science” of the nature of scientific knowledge. PMID:18197311

  9. Attitude control of an object commonly held by multiple robot arms - A Lyapunov approach

    Science.gov (United States)

    Kreutz, Kenneth; Wen, John T.

    1988-01-01

    Multiple robot arms moving a commonly held object can be viewed as complex actuators whose purpose is to provide net forces and moments to the object. These forces and moments can be used to control the orientation, or attitude, of the object via the Euler equation describing attitude evolution in response to applied moments at the mass center. In contrast to the common approach that feedback-linearizes the attitude dynamics to a double integrator form with respect to some three-parameter local representation of orientation, the authors control the object using a globally nonsingular representation. Using an energy-motivated Liapunov function, globally stable control of attitude is shown.

  10. Attitude control of an object commonly held by multiple robot arms - A Lyapunov approach

    Science.gov (United States)

    Kreutz, Kenneth; Wen, John T.

    1988-01-01

    Multiple robot arms moving a commonly held object can be viewed as complex actuators whose purpose is to provide net forces and moments to the object. These forces and moments can be used to control the orientation, or attitude, of the object via the Euler equation describing attitude evolution in response to applied moments at the mass center. In contrast to the common approach that feedback-linearizes the attitude dynamics to a double integrator form with respect to some three-parameter local representation of orientation, the authors control the object using a globally nonsingular representation. Using an energy-motivated Liapunov function, globally stable control of attitude is shown.

  11. Geophysical astrophysical spectral-element adaptive refinement (GASpAR): Object-oriented h-adaptive fluid dynamics simulation

    Science.gov (United States)

    Rosenberg, Duane; Fournier, Aimé; Fischer, Paul; Pouquet, Annick

    2006-06-01

    An object-oriented geophysical and astrophysical spectral-element adaptive refinement (GASpAR) code is introduced. Like most spectral-element codes, GASpAR combines finite-element efficiency with spectral-method accuracy. It is also designed to be flexible enough for a range of geophysics and astrophysics applications where turbulence or other complex multiscale problems arise. The formalism accommodates both conforming and non-conforming elements. Several aspects of this code derive from existing methods, but here are synthesized into a new formulation of dynamic adaptive refinement (DARe) of non-conforming h-type. As a demonstration of the code, several new 2D test cases are introduced that have time-dependent analytic solutions and exhibit localized flow features, including the 2D Burgers equation with straight, curved-radial and oblique-colliding fronts. These are proposed as standard test problems for comparable DARe codes. Quantitative errors are reported for 2D spatial and temporal convergence of DARe.

  12. Dynamic Representations of Sparse Graphs

    DEFF Research Database (Denmark)

    Brodal, Gerth Stølting; Fagerberg, Rolf

    1999-01-01

    We present a linear space data structure for maintaining graphs with bounded arboricity—a large class of sparse graphs containing e.g. planar graphs and graphs of bounded treewidth—under edge insertions, edge deletions, and adjacency queries. The data structure supports adjacency queries in worst...... case O(c) time, and edge insertions and edge deletions in amortized O(1) and O(c+log n) time, respectively, where n is the number of nodes in the graph, and c is the bound on the arboricity....

  13. Dynamics of 3D view invariance in monkey inferotemporal cortex.

    Science.gov (United States)

    Ratan Murty, N Apurva; Arun, Sripati P

    2015-04-01

    Rotations in depth are challenging for object vision because features can appear, disappear, be stretched or compressed. Yet we easily recognize objects across views. Are the underlying representations view invariant or dependent? This question has been intensely debated in human vision, but the neuronal representations remain poorly understood. Here, we show that for naturalistic objects, neurons in the monkey inferotemporal (IT) cortex undergo a dynamic transition in time, whereby they are initially sensitive to viewpoint and later encode view-invariant object identity. This transition depended on two aspects of object structure: it was strongest when objects foreshortened strongly across views and were similar to each other. View invariance in IT neurons was present even when objects were reduced to silhouettes, suggesting that it can arise through similarity between external contours of objects across views. Our results elucidate the viewpoint debate by showing that view invariance arises dynamically in IT neurons out of a representation that is initially view dependent.

  14. A TOOL FOR A DYNAMIC ADAPTATION OF THE OBJECTIVES AT THE LEVELS OF EUROPEAN UNION, NATIONAL AND SECTORAL, UNDER SECTORAL AND ACROSS SECTORS

    Directory of Open Access Journals (Sweden)

    Speranţa-Liliana NEAGU

    2016-06-01

    Full Text Available Changing of paradigms and realities generated by the dynamism shaping of international relations and the reality, especially determines a necessity of rapid modernization objectives to adapt to new constructs strategies and rules (soft law, common law and customary law, on the other hand. Creating of the conditions to open a chapter of the EU accession, or preparation of the content of acts of delegation or implementation concomitant of provisions of the EU Commission, to achieve the interests of socio-political nations, integrated - must be based on targets set by decisions triangular (COM; PE; CONS3 and through the "six thinking hats"4" – Maltese psychologist Edward de Bono.5 I created a simple tool for adaptation of the EU, national, sectoral, cross-sectoral objectives comparative for adaptation at dynamic reality. I created a simple tool for adaptation of the EU, national, sectoral, cross-sectoral objectives comparative for adaptation at dynamic reality.

  15. Adaptive grid based multi-objective Cauchy differential evolution for stochastic dynamic economic emission dispatch with wind power uncertainty.

    Science.gov (United States)

    Zhang, Huifeng; Lei, Xiaohui; Wang, Chao; Yue, Dong; Xie, Xiangpeng

    2017-01-01

    Since wind power is integrated into the thermal power operation system, dynamic economic emission dispatch (DEED) has become a new challenge due to its uncertain characteristics. This paper proposes an adaptive grid based multi-objective Cauchy differential evolution (AGB-MOCDE) for solving stochastic DEED with wind power uncertainty. To properly deal with wind power uncertainty, some scenarios are generated to simulate those possible situations by dividing the uncertainty domain into different intervals, the probability of each interval can be calculated using the cumulative distribution function, and a stochastic DEED model can be formulated under different scenarios. For enhancing the optimization efficiency, Cauchy mutation operation is utilized to improve differential evolution by adjusting the population diversity during the population evolution process, and an adaptive grid is constructed for retaining diversity distribution of Pareto front. With consideration of large number of generated scenarios, the reduction mechanism is carried out to decrease the scenarios number with covariance relationships, which can greatly decrease the computational complexity. Moreover, the constraint-handling technique is also utilized to deal with the system load balance while considering transmission loss among thermal units and wind farms, all the constraint limits can be satisfied under the permitted accuracy. After the proposed method is simulated on three test systems, the obtained results reveal that in comparison with other alternatives, the proposed AGB-MOCDE can optimize the DEED problem while handling all constraint limits, and the optimal scheme of stochastic DEED can decrease the conservation of interval optimization, which can provide a more valuable optimal scheme for real-world applications.

  16. Mental health and social networks in early adolescence: a dynamic study of objectively-measured social interaction behaviors.

    Science.gov (United States)

    Pachucki, Mark C; Ozer, Emily J; Barrat, Alain; Cattuto, Ciro

    2015-01-01

    How are social interaction dynamics associated with mental health during early stages of adolescence? The goal of this study is to objectively measure social interactions and evaluate the roles that multiple aspects of the social environment--such as physical activity and food choice--may jointly play in shaping the structure of children's relationships and their mental health. The data in this study are drawn from a longitudinal network-behavior study conducted in 2012 at a private K-8 school in an urban setting in California. We recruited a highly complete network sample of sixth-graders (n = 40, 91% of grade, mean age = 12.3), and examined how two measures of distressed mental health (self-esteem and depressive symptoms) are positionally distributed in an early adolescent interaction network. We ascertained how distressed mental health shapes the structure of relationships over a three-month period, adjusting for relevant dimensions of the social environment. Cross-sectional analyses of interaction networks revealed that self-esteem and depressive symptoms are differentially stratified by gender. Specifically, girls with more depressive symptoms have interactions consistent with social inhibition, while boys' interactions suggest robustness to depressive symptoms. Girls higher in self-esteem tended towards greater sociability. Longitudinal network behavior models indicate that gender similarity and perceived popularity are influential in the formation of social ties. Greater school connectedness predicts the development of self-esteem, though social ties contribute to more self-esteem improvement among students who identify as European-American. Cross-sectional evidence shows associations between distressed mental health and students' network peers. However, there is no evidence that connected students' mental health status becomes more similar in their over time because of their network interactions. These findings suggest that mental health during early

  17. Large-scale hydropower system optimization using dynamic programming and object-oriented programming: the case of the Northeast China Power Grid.

    Science.gov (United States)

    Li, Ji-Qing; Zhang, Yu-Shan; Ji, Chang-Ming; Wang, Ai-Jing; Lund, Jay R

    2013-01-01

    This paper examines long-term optimal operation using dynamic programming for a large hydropower system of 10 reservoirs in Northeast China. Besides considering flow and hydraulic head, the optimization explicitly includes time-varying electricity market prices to maximize benefit. Two techniques are used to reduce the 'curse of dimensionality' of dynamic programming with many reservoirs. Discrete differential dynamic programming (DDDP) reduces the search space and computer memory needed. Object-oriented programming (OOP) and the ability to dynamically allocate and release memory with the C++ language greatly reduces the cumulative effect of computer memory for solving multi-dimensional dynamic programming models. The case study shows that the model can reduce the 'curse of dimensionality' and achieve satisfactory results.

  18. Modeling surface water dynamics in the Amazon Basin using MOSART-Inundation v1.0: impacts of geomorphological parameters and river flow representation

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Xiangyu; Li, Hongyi; Leung, Lai-Yung; Tesfa, Teklu K.; Getirana, Augusto; Papa, Fabrice; Hess, Laura L.

    2017-03-23

    Surface water dynamics play an important role in water, energy and carbon cycles of the Amazon Basin. A macro-scale inundation scheme was integrated with a surface-water transport model and the extended model was applied in this vast basin. We addressed the challenges of improving basin-wide geomorphological parameters and river flow representation for large-scale applications. Vegetation-caused biases embedded in the HydroSHEDS DEM data were alleviated by using a vegetation height map of about 1-km resolution and a land cover dataset of about 90-m resolution. The average elevation deduction from the DEM correction was about 13.2 m for the entire basin. Basin-wide empirical formulae for channel cross-sectional geometry were adjusted based on local information for the major portion of the basin, which could significantly reduce the cross-sectional area for the channels of some subregions. The Manning roughness coefficient of the channel varied with the channel depth to reflect the general rule that the relative importance of riverbed resistance in river flow declined with the increase of river size. The entire basin was discretized into 5395 subbasins (with an average area of 1091.7 km2), which were used as computation units. The model was driven by runoff estimates of 14 years (1994 – 2007) generated by the ISBA land surface model. The simulated results were evaluated against in situ streamflow records, and remotely sensed Envisat altimetry data and GIEMS inundation data. The hydrographs were reproduced fairly well for the majority of 13 major stream gauges. For the 11 subbasins containing or close to 11 of the 13 gauges, the timing of river stage fluctuations was captured; for most of the 11 subbasins, the magnitude of river stage fluctuations was represented well. The inundation estimates were comparable to the GIEMS observations. Sensitivity analyses demonstrated that refining floodplain topography, channel morphology and Manning roughness coefficients, as

  19. Use of Self-to-Object and Object-to-Object Spatial Relations in Locomotion

    Science.gov (United States)

    Xiao, Chengli; Mou, Weimin; McNamara, Timothy P.

    2009-01-01

    In 8 experiments, the authors examined the use of representations of self-to-object or object-to-object spatial relations during locomotion. Participants learned geometrically regular or irregular layouts of objects while standing at the edge or in the middle and then pointed to objects while blindfolded in 3 conditions: before turning (baseline),…

  20. Efficient visual tracking via low-complexity sparse representation

    Science.gov (United States)

    Lu, Weizhi; Zhang, Jinglin; Kpalma, Kidiyo; Ronsin, Joseph

    2015-12-01

    Thanks to its good performance on object recognition, sparse representation has recently been widely studied in the area of visual object tracking. Up to now, little attention has been paid to the complexity of sparse representation, while most works are focused on the performance improvement. By reducing the computation load related to sparse representation hundreds of times, this paper proposes by far the most computationally efficient tracking approach based on sparse representation. The proposal simply consists of two stages of sparse representation, one is for object detection and the other for object validation. Experimentally, it achieves better performance than some state-of-the-art methods in both accuracy and speed.