Two 7-R manipulators which provide controllably dexterous workspace

In this paper, kinematic analysis and motion planning of a quadruped robot are presented by regarding the robot as an equivalent parallel platform-type mechanism with RRRS limb structure. Based on screw theory, the mobility of the quadruped robot with different touchdown legs is analyzed, and proves that the design for degree of freedom (DOF) is available. Base on the established kinematic model of a single leg in terms of POE formula of screw theory, several typical patterns of walking motion planning are implemented and verified by the ADAMS-based simulation. In order to show a good maneuverability and potential manipulation capability of the quadruped robot as a parallel manipulator, the gait planning reflecting two rotating motion patterns (including the rotating motion and walking motion) is modeled and simulated by kinematics of the equivalent parallel manipulators. Finally, a prototype of the quadruped robot has been built. Experimental test shows the practical walking and rotating ability as desired.

The problem of distance computation arises in many applications including motion planning, CAD/CAM, dynamic simulation and virtual environments. Most prior work in this area has been restricted to separation or penetration distance computation between two objects. In this paper, we address the problem of computing a measure of distance between two configurations of a rigid or articulated model. The underlying distance metric is defined as the length of the longest displacement vector over the corresponding vertices of the model between two configurations. Our algorithm is based on Chasles theorem in Screw theory, and we show that the maximum distance can be realized only by a vertex of the convex hull of a rigid object. We use this formulation to compute the distance, and present two acceleration techniques to speed up the computation: incremental walking on the dual space of the convex hull and culling vertices on the convex hull using a bounding volume hierarchy (BVH). Our algorithm can be easily extended to articulated models by maximizing the distance over its each link and we also present culling techniques to accelerate the computation. We highlight the performance of our algorithm on many complex models and describe its application to proximity queries and motion planning.

Clinical decision making – personal characteristics lead to the planning of effective treatments. Personalized medicine has become popular and has created new opportunities in clinical situations in recent years. Personalized realistic and appropriate health improvement plans for patient health conditions are considered as an important component of shared decision making. However, planning and taking effective action largely depend on the empirical judgment of the clinicians in clinical situations, and objective health improvement planning that is beneficial to both patients and clinicians is difficult. New data-driven treatment planning frameworks that can effectively plan health improvement processes to a practical level are proposed. There are public plans and models that propose treatment motion plans where it is possible to confirm that the planned motion plans are actionable and are in good agreement with clinical knowledge for the improvement of objective health factors. In addition, the proposed action helps clinicians to easily take patient-acceptable actions. Clinical outcomes show that the proposed planning motion plans effectively improve health factors. Finally, comparisons with conventional designs and encoding motion plans are performed for fixed-time set control functions. The results show that the proposed encoding motion plan can effectively improve the control objective by extending the action time by taking a feasible improvement action in time to compare the conveniences with the fixed-time set control function. Despite the numerous recent successes, it is still largely unclear how ML can support clinical decision-making. Ideally, after taking any data into account, it would be possible to classify the patient under the correct diagnosis. In human decision-making, a clinician would ideally explore all the available data and compare them to patients they have seen before or were trained to recognize. Because of this, numerous personal factors such as the knowledge and experience of the clinician, the time available, the noisy communication of diagnostic results, and even mood may bias the decision. For standardization, many professional organizations provide guidelines on how to manage patients under the best available evidence. This accumulation of evidence is generally based exclusively on data obtained from large cohorts of patients and, in general, corresponds to the average behavior of the population. However, these guidelines often ignore a large number of factors, both personal – sex, age, genetic predisposition, among others – and environmental – lifestyle, diet – that may be of relevance.

This paper proposes a novel performance index, which is called static actuation force sensitivity (SAFS), to investigate the response of the actuation forces when the amplitude of the suffered load of the end-effector has a change. Smaller SAFS can protect the actuations, and the load is mainly suffered by the structural constraints. This work starts with the construction of the unified forward Jacobian matrix of both serial and parallel mechanisms by screw theory. Then, with the forward Jacobian matrix, the inverse static equation is established. SAFS is thus introduced by the “partial differential” operation on the inverse static equation. SAFS is only related to the position of the whole mechanism and the direction of the suffered load, but not related to the detailed value of the amplitude of the load and the detailed value of the actuation forces; thus, SAFS can reveal the essence of static force capacities of the mechanisms. The example mechanism (namely, the 3revolute-prismatic-spherical (RPS) parallel mechanism) is used to illustrate the distribution of SAFS both over the workspace and at a certain pose. The analysis method of SAFS and the proposed index are expected to be applied to the pose optimization in the motion planning of the mechanisms to protect the actuations.

Autonomous driving has shown the capability of providing driver convenience and enhancing safety. While introducing autonomous driving into our current traffic system, one significant issue is to make the autonomous vehicle be able to react in the same way as real human drivers. In order to ensure that an autonomous vehicle of the future will perform like human drivers, this paper proposes a vehicle motion planning model, which can represent how drivers control vehicles based on the assessment of traffic environments in the real signalized intersection. The proposed motion planning model comprises functions of pedestrian intention detection, gap detection and vehicle dynamic control. The three functions are constructed based on the analysis of actual data collected from real traffic environments. Finally, this paper demonstrates the performance of the proposed method by comparing the behaviors of our model with the behaviors of real pedestrians and human drivers. The experimental results show that our proposed model can achieve 85% recognition rate for the pedestrian crossing intention. Moreover, the vehicle controlled by the proposed motion planning model and the actual human-driven vehicle are highly similar with respect to the gap acceptance in intersections.

In nuclear fusion research, inspecting tokamak vessel by controlling remote-handling robot is promising. To achieve collision-free, precise robot movement in tokamak vessel, it is necessary for the control system to perform motion planning, closed-loop control, interface operation and other functions. In this paper, a control system based on Ethernet and CAN network for a developed snake-like robot for inspecting tokamak vessel is proposed. Then, the robot kinematics model is built. Motion planning procedure is completed by a stepwise iterative algorithm. And a dual-loop control method for each joint is realized. A control software is developed to perform control computation and interface operation. Finally, the effectiveness of the control system for the robot is verified by actual experiments.

SUMMARYIn this paper, a kinematic model of a dual-arm/hand robotic system is derived, which allows the computation of the object position and orientation from the joint variables of each arm and each finger as well as from a suitable set of contact variables. On the basis of this model, a motion planner is designed, where the kinematic redundancy of the system is exploited to satisfy some secondary tasks aimed at ensuring grasp stability and manipulation dexterity without violating physical constraints. To this purpose, a prioritized task sequencing with smooth transitions between tasks is adopted. Afterwards, a controller is designed so as to execute the motion references provided by the planner and, at the same time, achieve a desired contact force exerted by each finger on the grasped object. To this end, a parallel position/force control is considered. A simulation case study has been developed by using the dynamic simulator GRASPIT!, which has been suitably adapted and redistributed.

This paper makes a theoretical and practical study on enterprise risk management based on combination of risk management theory and actual case. The article uses relevant theory and methods to analyze the risk management result of the SHELL ENTERPRISE case, and summarizes systematically the process and functions of risk identification, risk analysis, risk management and risk control, which is reference to enterprise risk management of our country. Through the analysis of specific case, it concludes that enterprise risk management is a process and using the effective measures to manage the risk timely is essential for creating and maintaining the value of the enterprise.

Human visual-motor coordination is an important function of motor control, and requires interactions of multiple brain regions and muscles. It is of great significance to understand the visual-motor coordination, specially for the dynamic phase of task planning and execution. This study is aimed to establish an effective connectivity analysis method and explore visual-motor coordination mechanism. A hand-grip experiment with four conditions of relaxation, vision only, grip only, and visually-guided grip, was designed. High-density EEG and surface EMG from the extensor carpi radialis longus muscle and the flexor carpi radialis muscle of the right forearm were recorded. Movement-related cortical potentials (MRCP) were extracted from EEG signals to quantify the spatio-temporal activities in the brain, and root-mean-square (RMS) values were calculated for the EMG signals. Subsequently, effective connectivity strength was obtained with Granger Causality for primary visual area to supplementary and pre-motor areas, then to primary motor area, down to the muscles, and also from the muscles back to the primary motor area. During the dynamic phase of the two grip conditions, clear causality was observed from brain visual perception to motion planning and execution, then to muscles contraction, and back to the brain. Statistical analysis of MRCP revealed significant activation differences in the central and occipital regions as the grip force increased, in compared with the relaxation condition. The muscles were activated earlier in the grip only condition than in the visually-guided grip condition. Therefore, the proposed experimental paradigm and analysis method have the potential to explore human visual-motor coordination.

A variety of LQR-RRT kinodynamic motion planners are built on the idea of solving a two point boundary value problem in an LQR manner for affine systems. These planners can also be used for controllable nonlinear systems only if its linearized model at the equilibrium state is also controllable, and the cost function reflects only a time/control trade-off. We propose a class of RRT planners based on the SDRE (State Dependent Riccati Equation) control paradigm. The SDRE control is used both for finding the nearest state in the tree and for the tree expansion. By solving an LQR tracking problem for nonlinear systems within the SDRE framework, instead of a two point boundary value problem, the proposed planners deal with a wider range of controllable nonlinear systems and cost functions. We compare the proposed planners with LQR-RRT-like algorithms by observing the results obtained from the three specific benchmark examples.

Two features of the globalising economy are its technological dynamism and its increasing service orientation. International tourism is an important element of the “new economy” of globalisation, as are new information and communication technologies. The relations between these two central elements of the reconfiguring world system have been under-theorised. Based on extensive primary fieldwork in Western Cape Province, South Africa, this paper explores the impact of new information and communication technologies on tourism development. It finds that, while these new technologies are extensively used in marketing and booking, in particular, foreign-owned websites have established a dominant command and control function, thereby replicating previous patterns of economic extraversion.

Alzheimer's Disease (AD) is a type of progressive dementia that causes loss of memory and function. It affects over 5.8 million people sixty years of age and older in the United States alone. When an individual has AD, neurodegeneration ultimately leads to severe impairment and eventually death. Throughout the stages of the disease, symptoms can range from mild forgetfulness to loss of motor control and bodily functions. Unfortunately, the disease may go unnoticed during initial stages if not tested for and detected early. Signs of Alzheimer's may accidentally be overlooked by physicians, especially if they are subtle. Artificial intelligence (AI) and machine learning models (ML) can be used to improve the identification process of early signs of AD. Some neuropsychological impairments AD patients suffer from include memory loss, difficulty recalling words or phrases, changes in personality and behavior, and decline in bodily functions that affect day to day life. AI may be able to pick up certain details and data that human perception cannot. If trained with a proper data set, ML models would be helpful to physicians in this area of healthcare. In this systematic review, the different neuropsychological impairments visible in the early stages of AD will be discussed as they relate to ML, deep learning, and AI applications intended to aid the diagnosis of AD.

This review aims to identify the current status of the hearing aid fitting program and applications for six major manufacturers in terms of security system and to suggest supplementary methods and solutions for strengthening security. First of all, we analyzed the hearing aid fitting programs and applications for the six manufacturers. When the hearing aid fitting programs were executed, we examined authentication processes, encryption systems, and individual data logging operations. To identify whether a third party could access and operate the hearing aid through the application, authentication processes and technologies used for connection between the hearing aid and the application were also examined. Among the six hearing aid fitting programs, two manufacturers' systems had authentication processes, one had access control program installed in the customer database, and the individual data logging could turn on/off in five hearing aid fitting programs. All manufacturers had no authentication processes in the hearing aid applications. Bluetooth was used for connection technology for all manufacturers, and the acoustic signal was used in two manufacturers' programs. In most cases, the third parties were able to control the hearing aid using the vulnerability of Bluetooth and the acoustic signal. It is necessary to improve the security system by applying users authentication process, customer data encryption, role-based access control, audit trail, and automatic update function to the hearing aid fitting program. The security system of hearing aid application connected to Bluetooth and/or acoustic signal should be improved by adding a function of the user authentication and identification process of particular hearing aid for application usage.

<p>Understanding the anisotropic flow of ice is likely a key factor for the reliable prediction of the evolution of certain regions of the Earth’s ice sheets. Anisotropy of the crystal lattice alignment of ice grains is typically neglected in the large majority of ice-sheet models, however the viscosity of ice can vary by a factor of at least 9 in different directions, indicating the potential to provide a dominant control. Even though anisotropy can have a large regional influence, its effects are currently poorly understood. For example, it is an open question as to how different varieties of crystal fabrics are produced by different forms of deformation, and how these dynamics vary with temperature.</p><p>To address these questions, we use a continuum-mesoscopic approach, proposed by Faria (2006a) and Placidi (2010) to model the evolution of the ice crystallographic preferred orientations (CPOs). The model assumes strain induced crystal lattice rotation i.e. crystal plasticity with rigid body rotation where parameters representing the following processes are incorporated: the relative importance of basal slip, the magnitude of grain-boundary migration and the magnitude of rotation recrystallization. We solve the system using a new spectral method, which is computationally highly efficient, and able to fully resolve the multiple dimensions of the problem (time, space and the two dimensions of orientation angle). By considering the predictions of the model in the cases of deformation representing shear and compression, the model is determined to reproduce all the detail features observed in ice CPOs evolution such as secondary clusters or cone shapes. The results show excellent agreement with experiments of ice deformation in both shear and compression. The experimental comparison is used to determine the first constraints on three temperature-dependent dimensionless numbers defining the relative important of the recrystallization and slip processes. With these dependencies constrained using shear experiments, the application of the model results is able to reproduce the observations of crystal structure in compressive experiments with no further fitting parameters. The model is thus found to provide good agreement with laboratory experiments  across a range of temperatures, strain rates and flow fields.  Moreover, the predicted patterns correspond qualitatively to those observed in natural ice from cores, with our results providing the first theoretical demonstration of the characteristics of the fabric structure. </p>

This study analyses the political discourse on immigration in Greece, Italy and Spain, with a view to highlighting how discourse is organised and, in particular, the use of ingroup and outgroup categories in it. It is hypothesised that talk on immigration involves a re-elaboration of national identity and re-definition of the ingroup/nation and outgroup/immigrant representation. Moreover, it is expected that immigrants are represented as Others, alien to the ingroup and, therefore, to be excluded from the host society. My aim here is to highlight the commonality of identity processes activated in different social-historical contexts and analyse the connection between ingroup-outgroup representations and the specific historical legacy and socio-economic reality of a given country. Greece, Italy and Spain have been selected as a suitable set of case studies because they have recently been transformed from senders to hosts of migrants. The section that follows describes briefly the size of the immigration phenomenon in each country and the public policies adopted. The second section discusses the ingroup-outgroup dynamics activated in immigration discourse from a sociological and a social psychological perspective. The third section concentrates on the analysis of political discourse, namely interviews with non-governmental organisations, trade union representatives and public administration employees in Athens, Rome and Madrid. The methodology used is that of qualitative discourse analysis. Findings are discussed under the light of sociological and social psychological research on the issue. Copyright © 2000 John Wiley & Sons, Ltd.