Workspace Model Research Articles

Auditory–visual integration during nonconscious perception

Our study proposes a test of a key assumption of the most prominent model of consciousness – the global workspace (GWS) model (e.g., Baars, 2002, 2005, 2007; Dehaene & Naccache, 2001; Mudrik, Faivre, & Koch, 2014). This assumption is that multimodal integration requires consciousness; however, few studies have explicitly tested if integration can occur between nonconscious information from different modalities. The proposed study examined whether a classic indicator of multimodal integration – the McGurk effect – can be elicited with subliminal auditory–visual speech stimuli. We used a masked speech priming paradigm developed by Kouider and Dupoux (2005) in conjunction with continuous flash suppression (CFS; Tsuchiya & Koch, 2005), a binocular rivalry technique for presenting video stimuli subliminally. Applying these techniques together, we carried out two experiments in which participants categorised auditory syllable targets which were preceded by subliminal auditory–visual (AV) speech primes. Subliminal AV primes were either illusion-inducing (McGurk) or illusion-neutral (Incongruent) combinations of speech stimuli. In Experiment 1, the categorisation of the syllable target (“pa”) was facilitated by the same syllable prime when it was part of a McGurk combination (auditory “pa” and visual “ka”) but not when part of an Incongruent combination (auditory “pa” and visual “wa”). This dependency on specific AV combinations indicated a nonconscious AV interaction. Experiment 2 presented a different syllable target (“ta”) which matched the predicted illusory outcome of the McGurk combination – here, both the McGurk combination (auditory “pa” and visual “ka”) and the Incongruent combination (auditory “ta” and visual “ka”) failed to facilitate target categorisation. The combined results of both Experiments demonstrate a type of nonconscious multimodal interaction that is distinct from integration – it allows unimodal information that is compatible for integration (i.e., McGurk combinations) to persist and influence later processes, but does not actually combine and alter that information. As the GWS model does not account for non-integrative multimodal interactions, this places some pressure on such models of consciousness.

Workspace layouts for communication quality in Scrum teams

Purpose of study to show the influence of workspace design on the quality of communication, especially on the Scrum team. The motivation is to find out the effect of changes in layout of the workspace on the quality of communication. Communication quality is an important concern about the performance of software development in the Scrum team. Problem: How does the layout change affect the Scrum team’s workspace on the quality of communication between members on a team; team members with other teams, and differences in the effect of changing layouts with old layouts. Methodology: Research steps use Participatory Action Research (PAR). This method has four main steps, namely planning; acting; observing; and reflecting. Data retrieval uses survey method by distributing questionnaires, conducting daily observations, and Forum Group Discussion (FGD). Findings: The Development Team Cell (DTC) workspace model is better than the Conference Cell (CC) model. This finding strengthens the previous research conducted by Scott and Pawel Role. Conclusion: There are three conclusions. a) changes in layout can improve the quality of individual communication. b) changes in layout have a positive effect on the quality of communication between team members and outside parties. c) changes in layout have a positive effect on team members’ understanding of the work and methods used.

A Self-Heuristic Ant-Based Method for Path Planning of Unmanned Aerial Vehicle in Complex 3-D Space With Dense U-Type Obstacles

Optimal path planning is required in autonomous navigation and intelligent control of the unmanned aerial vehicle (UAV). However, as a kind of common obstacles in complex three-dimensional (3-D) spaces, U-type obstacles may cause UAV to be confused and even lead to a collision or out of control. Although most of the Ant Colony Optimization (ACO) algorithm can generate proper path, solutions to U-type obstacles based on the specific behaviors of each ant are investigated rarely. Hence, different search strategies are studied and a novel ACO-based method called Self-Heuristic Ant (SHA) is proposed in this paper. The whole space is constructed by grid workspace model firstly, and then a new optimal function for UAV path planning is built. To avoid ACO deadlock state (i.e., ants are trapped in U-type obstacles when there is no optional successor node), two different search strategies are designed for choosing the next path node. In addition, the SHA is utilized to improve the ability of the basic ACO-based method. Specifically, besides pheromone update, a new information communion mechanism is fused to deal with the special areas which contain dense obstacles or many concave blocks. Finally, several experiments are investigated deeply. The results show that the deadlock state can be reduced effectively by the designed two different search strategies of ants. More importantly, compared with the conventional fallback strategy, the average number of retreats and the average running time of ACO can be reduced when SHA is applied.

On The Workspace Optimization of Parallel Robots Based on CAD Approach

Abstract This paper highlights workspace modeling of two parallel robots based on CAD technique. The algorithm is presented and described for the generation of each workspace, which is implemented in CATIA software. The impact of different design parameters on the reachable workspace of DELTA robot manipulator is discussed. Finally, an optimization example is given to show the effectiveness of the proposed approach.

Probabilistic Kinematic Model of a Robotic Catheter for 3D Position Control.

Continuum robots offer compliant and dexterous operations, which are suitable to be used in unstructured environments. Tendon-driven catheters, owing to their continuum structure, are applied in minimal invasive surgeries such as intracardiac interventions. However, due to the intrinsic nonlinearities and external disturbances, it is still a challenging task to accurately steer the catheter tip to the desired 3D positions. In this article, we proposed a new probabilistic kinematic model and a model-based three-dimensional position control scheme for a tendon-driven cardiac catheter. A dynamic Gaussian-based probabilistic model is developed to learn a mapping from the catheter states to the control actions. Based on the probabilistic model, a closed-loop position control is developed, in which the catheter is driven by a newly designed catheter driver system and tracked by a multiple near-infrared camera system. The proposed catheter framework is evaluated by the 3D trajectory tracking experiments both in a real 3D open space and in a minimum-energy-based simulator. The proposed control framework approximates the general kinematic by a combination of a catheter translation model and a distal workspace model, which provides the ability of automatically positioning the catheter tip in 3D and improving the accuracy by compensating the learned nonlinear effects.

Workspace Modeling and Path Planning for Truss Structure Inspection by Unmanned Aircraft

Small unmanned aircraft systems can increase efficiency and reduce risk to humans during the inspection of truss-supported structures such as steel bridges. This paper describes a method to mathematically represent a truss and subsequently to plan an efficient collision-free inspection path. The algorithm checks user-defined perspectives for feasibility and redefines any infeasible perspectives. A deterministic roadmap is then generated as the complete graph over these perspectives, and some additional nodes are generated near the joints of the structure. A traveling salesman problem (TSP) is solved to find an efficient inspection path that tours all perspective points, and a local A* path planner then refines the inspection path to circumvent obstructions. The TSP is re-solved, with an updated cost based on local detours; and the process iterates until a feasible TSP solution is found. The “lazy” approach to global and local planning, for which paths are checked for feasibility after the fact and amended if necessary, ensures quick convergence to an efficient inspection path. Simulation results show the functionality of the algorithm. Comparison with a probabilistic roadmap method indicates the proposed algorithm’s efficiency.

Workspace Planning Based on the Analysis of BIM Collisions

This article discusses a method for solving the problem of finding collisions of workspaces during construction. The solution of this problem is reduced to the solution of the basic problem of finding collisions (intersections) of geometric objects. Methods of classification, generation and analysis of workspace model are discussed. BIM technology is useful for creating 3D workspaces. Autodesk Revit was selected as a BIM software for creating digital building models and tools for creating workspaces. The scheme of interaction between BIM model and construction schedule is proposed to determine parameters of 3D workspace.

A novel hexapod and its prototype for secondary mirror alignment in telescopes

This paper presents a novel hexapod as the adjustment mechanism for a telescope to actively align its secondary mirror. The special hexapod provides six degrees of freedom (6-DOFs) with decoupled translation and rotation. The decoupled kinematic motions are analyzed and commented on as the alignment mechanism of a secondary mirror from an optical alignment point of view. In terms of performance of the adjustment generally required by the secondary mirror in a telescope, we developed a prototype that uses a novel hexapod design with linear micro-displacement actuators. Especially, in order to achieve high precision, flexures were used to build joints for the hexapod to minimize frictions and eliminate backlashes. Based on the specific configuration and dimension of the prototype hexapod, an analytical model of the reachable workspace was built with the constraints defined by limited rotation angles of the flexure-based joints. We used a laser tracker to verify that the hexapod can reach a spherical translation workspace of ϕ6 mm and a rotation workspace of ± 1°. The translational repeatability was tested to be around half a by laser displacement sensors. In addition, we also measured the axial and lateral stiffnesses of the hexapod to be around 5500 N mm−1 and 1750 N mm−1, respectively. The kinematic analyses and convincing test results jointly encourage implementing the novel hexapod design with decoupled translation and rotation as a favorable alignment mechanism for secondary mirrors in astronomical telescopes.

The offline stream of conscious representations.

When do we become conscious of a stimulus after its presentation? We would all agree that this necessarily takes time and that it is not instantaneous. Here, I would like to propose not only that conscious access is delayed relative to the external stimulation, but also that it can flexibly desynchronize from external stimulation; it can process some information 'offline', if and when it becomes relevant. Thus, in contrast with initial sensory processing, conscious experience might not strictly follow the sequence of events in the environment. In this article, I will review gathering evidence in favour of this proposition. I will argue that it offers a coherent framework for explaining a great variety of observations in the domain of perception, sensory memory and working memory: the psychological refractory period, the attentional blink, post-dictive phenomena, iconic memory, latent working memory and the newly described retro-perception phenomenon. I will integrate this proposition to the global neuronal workspace model and consider possible underlying brain mechanisms. Finally, I will argue that this capacity to process information 'offline' might have made conscious processing evolutionarily advantageous in spite of its sluggishness and capacity limitations.This article is part of the theme issue 'Perceptual consciousness and cognitive access'.

A time–space trade-off for computing the k-visibility region of a point in a polygon

Let P be a simple polygon with n vertices, and let q∈P be a point in P. Let k∈{0,…,n−1}. A point p∈P is k-visible from q if and only if the line segment pq crosses the boundary of P at most k times. The k-visibility region of q in P is the set of all points that are k-visible from q. We study the problem of computing the k-visibility region in the limited workspace model, where the input resides in a random-access read-only memory of O(n) words, each with Ω(log⁡n) bits. The algorithm can read and write O(s) additional words of workspace, where s∈N is a parameter of the model. The output is written to a write-only stream.Given a simple polygon P with n vertices and a point q∈P, we present an algorithm that reports the k-visibility region of q in P in O(cn/s+clog⁡s+min⁡{⌈k/s⌉n,nlog⁡logs⁡n}) expected time using O(s) words of workspace. Here, c∈{1,…,n} is the number of critical vertices of P for q where the k-visibility region of q may change. We generalize this result for polygons with holes and for sets of non-crossing line segments.

Computational Geometry Column 67

In the limited workspace model, we consider algorithms whose input resides in read-only memory and that use only a constant or sublinear amount of writable memory to accomplish their task. We survey recent results in computational geometry that fall into this model and that strive to achieve the lowest possible running time. In addition to discussing the state of the art, we give some illustrative examples and mention open problems for further research.

Car-like mobile robot path planning in rough terrain using multi-objective particle swarm optimization algorithm

Abstract This paper presents a path planning algorithm for car-like mobile robots operating on a known static rough terrain environment. The purpose of this approach is to find collision free and feasible paths with minimum length and terrain roughness. First, a new workspace modeling method is proposed to model the rough terrain environment. Then, considering the nonholonomic constraints of car-like robots, a MOPSO (multi-objective particle swarm optimization) based method is used to solve the problem. In the proposed algorithm, a new updating method for particle’s global best position based on crowding radius is used to increase population diversity. And to improve the algorithm efficiency, a nonuniformity factor is adopted to update the particle’s position when the path collides with obstacles. Finally, two simulation tests are designed using Microsoft Robotics Developer Studio 4 and Matlab. Results show the advantages of the proposed algorithm in finding Pareto optimal paths.

Performance evaluation of 3D descriptors for object recognition in construction applications

Abstract 3D object recognition from field-acquired point cloud data is important for modeling, manipulation, visualization and other post-processing tasks in the construction domain. However, building semantically-rich models from raw point cloud data is a difficult task due to the high volume of unstructured information as well as confounding factors such as noise and occlusion. Although there exist several computational recognition methods available, their performance robustness for construction applications are not well known. Therefore, this research aims to review and evaluate state-of-the-art descriptors for 3D object recognition from raw point clouds for construction applications such as workspace modeling, asset management and worker tracking. The evaluation was carried out using 3D CAD models with known labels as training data and laser-scanned point clouds from construction sites as testing data. The recognition performance was evaluated with respect to varying level of detail, noise level, degree of occlusion, and computation time. Experimental results show that for all evaluated descriptors, increasing the level of detail and decreasing the noise level results in a moderate increase in recognition accuracy whereas reducing occlusion results in a significant increase in recognition accuracy. In addition, experimental results suggest that the key features that distinguish an object can be derived around the 10 mm level and any further increase in the level of detail do not significantly increase the recognition accuracy.

Design of inverse dynamics tracking control system and voice based interfacing mechanism to the WMRA

Majority of wheelchair users with neuromuscular diseases experience upperbody muscular weakness, which limit their ability to perform common activities of daily living. A Wheelchair Mounted Robotic Arm (WMRA) can assist these individuals to perform various tasks independently. This research paper is focused on designing a control system and interfacing mechanism to a newly designed WMRA. The proposed interfacing mechanism is based on virtual image and voice activated signals. The paper outlined the implementation through three dimensional imagining and a virtual workspace model of the real world for the arm to navigate through. The user speaks a simple command through a microphone and then be run through a control algorithm to drive the robotic arm. Inverse dynamics based control scheme is implemented to command the active joints of the robot, based on an input from the virtual CAD environment. The preliminary simulation results show that the virtual model joint trajectories are well tracked with minimal error. The paper also outlined the overall implementation of the system using Robot Operating System based interfacing system.

Optimized vision-based robot motion planning from multiple demonstrations

This paper combines workspace models with optimization techniques to simultaneously address whole-arm collision avoidance, joint limits and camera field of view (FOV) limits for vision-based motion planning of a robot manipulator. A small number of user demonstrations are used to generate a feasible domain over which the whole robot arm can servo without violating joint limits or colliding with obstacles. Our algorithm utilizes these demonstrations to generate new feasible trajectories that keep the target in the camera’s FOV and achieve the desired view of the target (e.g., a pre-grasping location) in new, undemonstrated locations. To fulfill these requirements, a set of control points are selected within the feasible domain. Camera trajectories that traverse these control points are modeled and optimized using either quintic splines (for fast computation) or general polynomials (for better constraint satisfaction). Experiments with a seven degree of freedom articulated arm validate the proposed scheme.

A role for the anterior insular cortex in the global neuronal workspace model of consciousness.

According to the global neuronal workspace model of consciousness, consciousness results from the global broadcast of information throughout the brain. The global neuronal workspace is mainly constituted by a fronto-parietal network. The anterior insular cortex is part of this global neuronal workspace, but the function of this region has not yet been defined within the global neuronal workspace model of consciousness. In this review, I hypothesize that the anterior insular cortex implements a cross-modal priority map, the function of which is to determine priorities for the processing of information and subsequent entrance in the global neuronal workspace.

Построение трехмерной модели рабочего пространства промышленного робота

Построение трехмерной модели рабочего пространства промышленного робота

Investigating Learning Space for Research Workspaces in Higher Education in Malaysia

Purpose – The purpose of this paper is to investigate learning space for research workspaces in Higher Education Institutions (HEIs) in Malaysia based on the evaluations by experts and university research workers on a practical model for creating an effective research learning space. It examines expert analyses of the notion of a suitable research learning workspace and explores worker viewpoints on this issue.Method – Experts from business (n=2), education (n=2) and architectural (n=2) backgrounds were interviewed and a survey was conducted on research workers from selected universities in Malaysia (n=222). Findings – A research learning workspace model is proposed based on evaluations by workers and experts on what was needed in a research-based working space to make it more work-friendly and intellectually stimulating for researchers. Significance – This research attempts to understand research learning space problems in institutions of higher learning and proposes one possible model for future research learning workspace planning. It also contributes to the literature on research learning workspace and its management in developing countries, especially when Asia is positioning itself today as a competitive global educational hub.

Why the P3b is still a plausible correlate of conscious access? A commentary on Silverstein et al., 2015

We read with interest the article by Silverstein and colleagues (Silverstein, Snodgrass, Shevrin, & Kushwaha, 2015) who questioned the putative specificity of the P3b event-related potentials (ERP) component as a neural signature of conscious access to a visual representation. Prior to this new study, numerous empirical reports revealed that a brain response peaking ∼300 msec after stimulus onset and maximally distributed over parietal electrodes – the so called P3b – is closely related to subjective visibility (Sergent et al., 2005 and Vogel et al., 1998). These experimental findings provided the bases to develop neuronal and computational theories of consciousness such as the global workspace model (Dehaene and Changeux, 2011, Dehaene et al., 2006 and Dehaene and Naccache, 2001). Silverstein and colleagues used a ‘passive attentive’ version of a masked visual odd-ball paradigm while recording scalp ERPs. In each trial, subjects were presented with either the masked word ‘LEFT’ (in 80% or 20% of trials) or the masked word ‘RIGHT’ (in 20% or 80% of trials). Word frequency was balanced across subjects, who were asked to carefully attend to the masked sequence. Not only were they instructed that this sequence contained a masked word, but also that: “however implausible it might seem, our prior data suggested that the stimuli would nonetheless be unconsciously perceived and produce brain wave effects – but only if they maintained their attention”. When contrasting ERPs elicited by rare and frequent masked words, Silverstein and colleagues identified a P3b ERP component followed by a late, and sustained, slow wave (LSW). Given that participants subjectively reported the absence of conscious perception of words, and that they performed at chance-level in a stimulus detection task performed after the main experiment, Silverstein and colleagues concluded that a P3b can be observed during unconscious perception. If valid, their interpretation would then simply invalidate the P3b as a possible candidate neural signature of conscious access. This original and provocative study, however, raises both methodological and conceptual concerns which need to be addressed before one can adopt Silverstein and colleagues' interpretation.

El rol del profesor desde la perspectiva de los Espacios de Trabajo Matemático

Resumen En este artículo se presenta el modelo Espacio de Trabajo Matemático (ETM). Se pone de manifiesto el dinamismo de este modelo para reflexionar sobre la acción del profesor en el aula y sobre elementos importante a tener en cuenta en su formación. Los ETM se construyen con base en el conocimiento matemático y la experiencia del sujeto al hacer matemáticas, de ahí que su organización remita a dos planos: el epistemológico y el cognitivo, que serán el centro de la discusión de este trabajo. Se presentan las contribuciones al monográfico en las dinámicas que establecen el rol del docente en los conocimientos y las interacciones en el aula, desde dos puntos de vista en la formación de docente y en el rol del docente con los alumnos.