Slowness and Sparseness Lead to Place, Head-Direction, and Spatial-View Cells

We present a model for the self-organized formation of place cells, head-direction cells, and spatial-view cells in the hippocampal formation based on unsupervised learning on quasi-natural visual stimuli. The model comprises a hierarchy of Slow Feature Analysis (SFA) nodes, which were recently shown to reproduce many properties of complex cells in the early visual system. The system extracts a distributed grid-like representation of position and orientation, which is transcoded into a localized place-field, head-direction, or view representation, by sparse coding. The type of cells that develops depends solely on the relevant input statistics, i.e., the movement pattern of the simulated animal. The numerical simulations are complemented by a mathematical analysis that allows us to accurately predict the output of the top SFA laye

Recording of natural head position using stereophotogrammetry: A new technique and reliability study

The purpose of this study was to develop a technique to record physical references and orient digital mesh models to natural head position (NHP) using stereo-photogrammetry (SP). The first step was to record the digital mesh model of a hanging reference board placed at the capturing position of the SP machine. The board was aligned to the true vertical using a plumb bob. It was also aligned with laser plane parallel to the hanging mirror which was located at the center of the machine. Parameter derived from the digital mesh model of the board was then used to adjust the roll, pitch and yaw of the subsequent captures of subjects. This information was valid until the next machine calibration. The board placement was repeatable with standard deviation of less than 0.1 degrees for both pitch and yaw; 0.15 degrees for roll angles.postprin

The export competitiveness of the newly industrialised east Asian economies: How real is the Chinese threat in electronics?

This paper examines the export performance of China in electronics compared to the east Asian NIEs exporting to the USA, the European Union, and Japan between 1988 and 2001 using a dynamic version of shift-share analysis to overcome some of the inherent drawbacks of the widely-used static shift-share methodology. Our findings suggest that China has now emerged as a serious contender in the export market for electronic goods, but this position has not been a dominant one. For electronics as a whole, the principal gainers after 1995 appear to be newcomers China and Malaysia at the expense of the older Tigers, like Singapore and Hong Kong. To some extent this represents a natural process of ‘catch-up’. Moreover, no single NIE has dominated all categories of electronic exports. In the east Asian region, the less developed members of ASEAN would appear to be most at risk in the immediate future since they compete head on with China in lower-end manufacturing and are in danger of being ‘leapfrogged’ in the value-added chain. The more advanced NIEs are in a better position since they have time to increase value-added before China catches up and may benefit more from the opportunities China offers in terms of production and service complementarities

Dizziness and unsteadiness following whiplash injury: Characteristic features and relationship with cervical joint position error

Dizziness and/or unsteadiness are common symptoms of chronic whiplash-associated disorders. This study aimed to report the characteristics of these symptoms and determine whether there was any relationship to cervical joint position error. Joint position error, the accuracy to return to the natural head posture following extension and rotation, was measured in 102 subjects with persistent whiplash-associated disorder and 44 control subjects. Whiplash subjects completed a neck pain index and answered questions about the characteristics of dizziness. The results indicated that subjects with whiplash-associated disorders had significantly greater joint position errors than control subjects. Within the whiplash group, those with dizziness had greater joint position errors than those without dizziness following rotation (rotation (R) 4.5degrees (0.3) vs 2.9degrees (0.4); rotation (L) 3.9degrees (0.3) vs 2.8degrees (0.4) respectively) and a higher neck pain index (55.3% (1.4) vs 43.1% (1.8)). Characteristics of the dizziness were consistent for those reported for a cervical cause but no characteristics could predict the magnitude of joint position error. Cervical mechanoreceptor dysfunction is a likely cause of dizziness in whiplash-associated disorder

Harmony, Head Proximity, and the Near Parallels between Nominal and Clausal Linkers

This paper puts forward a notion of harmonic word order that leads to a new generalisation over the presence or absence of disharmony: specific functional heads must cross-linguistically obey this notion of harmony absolutely, while for other categories the presence of harmony is simply a tendency. The difference between the two classes is defined by semantics. This approach allows us both to draw certain parallels between restrictions on word order in nominals and in clauses, and furthermore to explain why other expected parallels should fail to be realised completely, specifically as regards differences in the distribution of relative clauses in the NP and complement clauses in the sentence. Syntactically independent relative clause markers and subordinating complementisers share a striking restriction as regards ordering: relative clause markers are always initial in postnominal relative clauses, and final in prenominal relative clauses (Andrews 1975; Downing 1978; Lehmann 1984; Keenan 1985; De Vries 2002, 2005); similarly, initial subordinating Cs only appear in postverbal complement clauses, while final subordinating Cs are only possible where the complement clause is preverbal (Bayer 1996, 1997, 1999; Kayne 2000). In this paper, I provide new evidence from eighty genetically and geographically diverse languages of a third category sharing precisely the same restriction: linkers in the complex NP. These are syntactically independent, semantically vacuous heads, serving to mark the presence of a relationship between a noun and any kind of phrasal dependent (Rubin 2002; Den Dikken and Singhapreecha 2004; Philip 2009). The class of linkers in the NP therefore includes the ezafe in Indo-Iranian, the associative marker -a in Bantu, as well as purely functional adpositions such as of in English. Like relative clause markers and subordinating Cs, the linker always intervenes linearly between the superordinate head (the noun) and the subordinate dependent. Crucially, relative clause markers, subordinating Cs, and linkers in the NP form a natural class: they are syntactically independent, semantically vacuous words serving purely to mark the presence of a relationship between head and dependent. Any member of this class is a ‘linker’. I propose a theory of disharmony whereby linearisation rules targeting heads with specified semantics can require such heads to appear in a prominent position, either initial or final, irrespective of the general headedness of the language. Linkers, being semantically vacuous, are of course impervious to such rules; they will therefore always conform to the harmonic, or optimal, word order. I propose a theory of harmony whereby the optimal word order is determined by the interaction of three independently motivated harmonic word order constraints: Head Proximity (adapted from Rijkhoff 1984, 1986, cf. Head-Final Filter, Williams 1982), the preference for uniformity in headedness (initial or final), and the preference for clausal dependents to appear in final position (Dryer 1980, 1992). Where the three constraints compete, it is always Head Proximity that takes precedence. I show that the distribution of all three types of linker is fully captured by this proposal. Moreover, this theory of ordering also accounts for another well observed near parallel between clauses and nominals, as well as its exceptions. This concerns a left-right asymmetry in the distribution of clausal dependents: while in OV languages complement clauses appear with near equal frequency in both preverbal and postverbal position, in VO languages they are found uniquely in postverbal position (Dryer 1980; Hawkins 1994; Dryer 2009); similarly, in OV languages relative clauses are distributed relatively evenly between prenominal and postnominal position, whereas in VO languages they are almost always postnominal, with very few exceptions (Mallinson & Blake 1981; Hawkins 1983, 1990; Lehmann 1984; Keenan 1985; Dryer 1992, 2007, 2008; De Vries 2005). The theory predicts these exceptions to be permitted only in languages that are rigidly N-final. Hawkins’ (1983) Noun Modifier Hierarchy suggests that this prediction is borne out; apparent exceptions (cf. Dryer 2008) are found underlyingly to be N-final

A comparison between anamnestic, rhinomanometric and radiological methods of diagnosing mouthbreathing

Three methods of evaluating the mode of breathing were applied in 119 children aged 7-15 years who were to start orthodontic treatment for various malocclusions. The three methods were: the history, rhinomanometric recording of the nasal airflow and determination of the size of the airway on profile and frontal cephalograms. The variables describing the mode of breathing were correlated with the facial morphology and the natural position of the head and the cervical spine as recorded with profile cephalometry. There were no correlations between the results of the evaluation of the mode of breathing obtained with the three methods. Nor were there any correlations between these and the position of the head or the cervical spine. A history of mouth-breathing, the rhinomanometrically determined airflow through the nose and the size of the airway on the profile cephalogram were, however, correlated with the long face morphology characteristic of mouth-breathing. A diagnosis of mouth-breathing should be based on different supplementary methods, the history and the size of the airway on the profile cephalogram being at least as valuable as the rhinomanometric recordin

Lateral Vibration and Read/Write Head Servo Dynamics in Magnetic Tape Transport

Magnetic tape is a flexible mechanical structure having dimensions that areorders of magnitude different in its thickness, width, and length directions. In order to position the tape relative to the read/write head, guides constrain the tape\u27s lateral motion, but even the modest forces that develop during guiding can cause wear and damage to the tape\u27s edges. This paper presents antensioned axially-moving viscoelastic Euler–Bernoulli beam model used to simulate thentape\u27s lateral dynamics, the guiding forces, and the position errornbetween the data tracks and the read/write head. Lateral vibration can be excited by disturbances in the form of pack runout, flange impacts, precurvature of the tape in its natural unstressed state, and spiral stacking as tape winds onto the take-up pack. The guide model incorporates nonlinear characteristics including preload and deadbands in displacement and restoring force. A tracking servo model represents the ability of the read/write head\u27s actuator to track disturbances in the tape\u27s motion, and the actuator\u27s motion couples through friction with the tape\u27s vibration. Low frequency excitation arising from pack runout can excite high frequency position error because of the nonlinear characteristics of the guides and impacts against the pack\u27s flanges. The contact force developed between the tape and the packs\u27 flanges can be minimized without significantly increasing the position error by judicious selection of the flanges\u27 taper angle

Stride-Cycle Influences on Goal-Directed Head Movements Made During Walking

Horizontal head movements were studied in six subjects as they made rapid horizontal gaze adjustments while walking. The aim of the present research was to determine if gait-cycle events alter the head movement response to a visual target acquisition task. Gaze shifts of approximately 40deg were elicited by a step change in the position of a visual target from a central location to a second location in the left or right horizontal periphery. The timing of the target position change was constrained to occur at 25,50,75 and 100% of the stride cycle. The trials were randomly presented as the subjects walked on a treadmill at their preferred speed (range: 1.25 to 1.48 m/s, mean: 1.39 +/- 0.09 m/s ) . Analyses focused on the movement onset latencies of the head and eyes and on the peak velocity and saccade amplitude of the head movement response. A comparison of the group means indicated that the head movement onset lagged the eye onset (262 ms versus 252 ms). The head and eye movement onset latencies were not affected by either the direction of the target change nor the point in the gait cycle during which the target relocation occurred. However, the presence of an interaction between the gait cycle events and the direction of the visual target shift indicates that the peak head saccade velocity and head saccade amplitude are affected by the natural head oscillations that occur while walking

SALSA: A Novel Dataset for Multimodal Group Behavior Analysis

Studying free-standing conversational groups (FCGs) in unstructured social settings (e.g., cocktail party ) is gratifying due to the wealth of information available at the group (mining social networks) and individual (recognizing native behavioral and personality traits) levels. However, analyzing social scenes involving FCGs is also highly challenging due to the difficulty in extracting behavioral cues such as target locations, their speaking activity and head/body pose due to crowdedness and presence of extreme occlusions. To this end, we propose SALSA, a novel dataset facilitating multimodal and Synergetic sociAL Scene Analysis, and make two main contributions to research on automated social interaction analysis: (1) SALSA records social interactions among 18 participants in a natural, indoor environment for over 60 minutes, under the poster presentation and cocktail party contexts presenting difficulties in the form of low-resolution images, lighting variations, numerous occlusions, reverberations and interfering sound sources; (2) To alleviate these problems we facilitate multimodal analysis by recording the social interplay using four static surveillance cameras and sociometric badges worn by each participant, comprising the microphone, accelerometer, bluetooth and infrared sensors. In addition to raw data, we also provide annotations concerning individuals' personality as well as their position, head, body orientation and F-formation information over the entire event duration. Through extensive experiments with state-of-the-art approaches, we show (a) the limitations of current methods and (b) how the recorded multiple cues synergetically aid automatic analysis of social interactions. SALSA is available at http://tev.fbk.eu/salsa.Comment: 14 pages, 11 figure