Recursive dynamics in a class of systems on q-timescales with unbounded delays

2019 ◽  
Vol 352 ◽  
pp. 401-408
Author(s):  
Mehdi Nategh
Keyword(s):  
Recursive Dynamics

The Dialectics of Technology Standardization

MIS Quarterly ◽  
2021 ◽  
Vol 45 (3) ◽  
pp. 1187-1212
Author(s):  
Rikard Lindgren ◽  
◽  
Lars Mathiassen ◽  
Ulrike Schultze ◽  
◽  
...  
Keyword(s):  
Social Order ◽  
Research Study ◽  
Global Solutions ◽  
Public Interests ◽  
It Systems ◽  
Road Haulage ◽  
Technology Standard ◽  
Recursive Dynamics ◽  
New Social Order ◽  
Technology Standardization

Technology standardization unfolds as a dialectic process marked by paradoxical tensions. However, standardization research has yet to provide a dialectic analysis of how tensions and management responses interact recursively over time, and with what effect. In this paper, we apply dialectics to analyze an action research study of a Swedish initiative that developed and diffused a technology standard to facilitate the integration of disparate IT systems in road haulage firms. Drawing on the technology standardization literature and our empirical analysis, we engage in midrange theorizing to capture the recursive dynamics through which standard-setters construct and respond to manifestations of three latent tensions: development versus diffusion activities, private versus public interests, and local versus global solutions. Our resulting dialectic theorizing explicates how standard-setters bring these latent tensions into being; how they construct salient tensions through the oppositional logics of polarization, complementarity, and mutuality; how they manage these tensions through splitting, integrating, and suspension responses; and how consequential functional, architectural, and organizational standardization outcomes produce a new social order in which new tensions emerge. These theoretical insights contribute to both the technology standardization and dialectics literatures.

Efficient Human Motion Planning Using Recursive Dynamics and Optimal Control Techniques

1999 ◽  
Author(s):  
Janzen Lo ◽  
Dimitris Metaxas
Keyword(s):  
Optimal Control ◽  
Motion Planning ◽  
Closed Loop ◽  
High Efficiency ◽  
Human Motion ◽  
Lagrangian Formulation ◽  
Planning Problem ◽  
Tree Structures ◽  
Recursive Dynamics ◽  
Minimum Torque

Abstract We present an efficient optimal control based approach to simulate dynamically correct human movements. We model virtual humans as a kinematic chain consisting of serial, closed-loop, and tree-structures. To overcome the complexity limitations of the classical Lagrangian formulation and to include knowledge from biomechanical studies, we have developed a minimum-torque motion planning method. This new method is based on the use of optimal control theory within a recursive dynamics framework. Our dynamic motion planning methodology achieves high efficiency regardless of the figure topology. As opposed to a Lagrangian formulation, it obviates the need for the reformulation of the dynamic equations for different structured articulated figures. We use a quasi-Newton method based nonlinear programming technique to solve our minimum torque-based human motion planning problem. This method achieves superlinear convergence. We use the screw theoretical method to compute analytically the necessary gradient of the motion and force. This provides a better conditioned optimization computation and allows the robust and efficient implementation of our method. Cubic spline functions have been used to make the search space for an optimal solution finite. We demonstrate the efficacy of our proposed method based on a variety of human motion tasks involving open and closed loop kinematic chains. Our models are built using parameters chosen from an anthropomorphic database. The results demonstrate that our approach generates natural looking and physically correct human motions.

Deliberate and Emergent Changes on a Way Towards Electronic Document Management

2011 ◽  
pp. 320-333
Author(s):  
Tero Paivarinta ◽  
Airi Salminen
Keyword(s):  
Power Plant ◽  
Continuous Improvement ◽  
Process Improvement ◽  
Information Technologies ◽  
Quality System ◽  
Document Management ◽  
Electronic Document ◽  
Electronic Document Management ◽  
New Information ◽  
Recursive Dynamics

A unit of Fortum Service Ltd. operates and maintains the Rauhalahti power plant in Central Finland. In 1996-97, the unit launched a project pursuing coordinated organizationwide electronic document management (EDM). This case follows deliberate and emergent changes related to document management in the organization since the initiation of the project until February 2000. New information technologies were adopted, and responsibilities for continuous improvement of EDM were assigned. The continuous improvement was implemented as an extension of the ISO 9002 quality system earlier adopted for process improvement. The case shows that a shift from the paper-based era towards organizationwide EDM is a comprehensive change both affecting and affected by several components in the organization. EDM development in the organization was part of organization recursive dynamics where the quality system supported both planning for deliberate changes and reacting to emergent changes.

Efficient Recursive Dynamics and Real Time Simulation of Flexible Space Robots System

2013 ◽  
Vol 842 ◽  
pp. 546-552
Author(s):  
Fu Yang Tian ◽  
Yu Dao Li ◽  
Zhen Wang ◽  
Fa De Li
Keyword(s):  
Real Time ◽  
Rigid Base ◽  
Space Robots ◽  
Flexible Robots ◽  
Real Time Simulation ◽  
Space Operations ◽  
Time Simulation ◽  
Integration Techniques ◽  
Efficient Integration ◽  
Recursive Dynamics

As space robots gain more and more importance in space operations, it was becoming imperative to understand their distinctive dynamics. The dynamics model of the space flexible robots is very complex, and the differential equation derived from dynamics was solved difficultly and slowly. In this paper the efficient recursive O(n) dynamics algorithm of space flexible robots systems with rigid base and flexible manipulators was discussed, and the fast efficient integration method was used to solve this dynamics equation for real time simulation. Simulations results show that the dynamic modeling and fast efficient numerical integration techniques of flexible space robot proposed in this paper are very useful. Keyword: space robots;efficient dynamic; recursive; real time simulation

scholarly journals Phase transition in fiber bundle models with recursive dynamics

2003 ◽  
Vol 67 (4) ◽  
Author(s):  
Pratip Bhattacharyya ◽  
Srutarshi Pradhan ◽  
Bikas K. Chakrabarti
Keyword(s):  
Phase Transition ◽  
Fiber Bundle ◽  
Recursive Dynamics

Optimization-Based Seated Posture Prediction Considering Contact With Environment

2011 ◽  
Author(s):  
Brad Howard ◽  
Jingzhou James Yang
Keyword(s):  
Center Of Pressure ◽  
Optimization Techniques ◽  
The Body ◽  
Human Model ◽  
Joint Torques ◽  
Pressure Mapping ◽  
Support Reaction ◽  
Posture Prediction ◽  
Reaction Forces ◽  
Recursive Dynamics

People can spend much of everyday completing seated tasks. Therefore it is important to understand postures needed to complete seated tasks, and the associated environmental contacts. This paper presents a method to predict seated postures and the general forces needed in order to support resulting postural configurations. This study uses optimization techniques to predict human posture based on a 56 degree of freedom (DOF) 50th percentile female human model. The support reaction forces (SRFs) are predicted using joint torques and the zero-moment point (ZMP) formulation derived from the Lagrangian recursive dynamics. The SRFs are applied at points on the body based on center of pressure (COP) locations gathered from pressure mapping experiments. The specific application points include the two feet, the two thighs, and back. Multiple seated orientations based on an experimental study found in published literature are simulated. When comparing these simulation results to the literature data, a good correlation can be established, which provides an initial validation of the proposed methods.

Parallel Processing for Real-Time Dynamic System Simulation

1988 ◽  
Author(s):  
R. S. Hwang ◽  
D.-S. Bae ◽  
E. J. Haug ◽  
J. G. Kuhl
Keyword(s):  
Parallel Processing ◽  
Real Time ◽  
Equations Of Motion ◽  
Companion Paper ◽  
Time Dynamic ◽  
Closed Loop Systems ◽  
Time Simulation ◽  
Efficiency And Effectiveness ◽  
Generalized Force ◽  
Recursive Dynamics

Abstract A parallel processing algorithm based on the recursive dynamics formulation presented in a companion paper [1] is developed for multiprocessor implementation. Lagrange multipliers associated with cut-joint constraints for closed loop systems are eliminated systematically, resulting to a minimal set of equations of motion. Concurrent generation of the system inertia matrix and the generalized force vector is exploited. A new computational structure for dynamic analysis is proposed for real-time parallel processing. Real-time simulation of a vehicle is performed to illustrate efficiency and effectiveness of the algorithm, even for interactive man-in-the-loop simulation.

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