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Haken-Kelso-Bunz Model
The Haken-Kelso-Bunz (HKB) is a theoretical model of motor coordination originally formulated by Hermann Haken, J. A. Scott Kelso and H. Bunz. The model attempts to provide the framework for understanding coordinated behavior in living things. It accounts for experimental observations on human bimanual coordination that revealed fundamental features of self-organization: multistability, and phase transitions (switching). HKB is one of the most extensively tested quantitative models in the field of human movement behavior. Phase Transitions ('Switches') The HKB model differs from other motor coordination models with the addition of phase transitions (‘switches’). Kelso initially observed this phenomenon while conducting an experiment looking at subjects’ finger movements. Subjects oscillated their fingers rhythmically in the transverse plane (i.e., abduction-adduction) in one of two patterns, parallel or anti-parallel. In the parallel pattern, the finger muscles contract in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motor Coordination
Motor coordination is the orchestrated movement of multiple body parts as required to accomplish intended actions, like walking. This coordination is achieved by adjusting kinematic and kinetic parameters associated with each body part involved in the intended movement. The modifications of these parameters typically relies on sensory feedback from one or more sensory modalities ( see: multisensory integration), such as proprioception and vision. Properties Large Degrees of Freedom Goal-directed and coordinated movement of body parts is inherently variable because there are many ways of coordinating body parts to achieve the intended movement goal. This is because the degrees of freedom (DOF) is large for most movements due to the many associated neuro- musculoskeletal elements.Bernstein N. (1967). The Coordination and Regulation of Movements. Pergamon Press. New York. Some examples of non-repeatable movements are when pointing or standing up from sitting. Complexity The comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hermann Haken
Hermann Haken (born 12 July 1927) is physicist and professor emeritus in theoretical physics at the University of Stuttgart. He is known as the founder of synergetics. He is a cousin of the mathematician Wolfgang Haken, who proved the Four color theorem. He is a nephew of Werner Haken, a doctoral student of Max Planck. Biography After his studies in mathematics and physics in Halle (Saale) and Erlangen, receiving his PhD in mathematics in 1951 at the University of Erlangen and being guest lecturer at universities in the UK and US, Haken was appointed as a full professor in theoretical physics at the University of Stuttgart. His research has been in non linear optics (his specialities are laser physics, particle physics, statistical physics and group theory). Haken developed his institute in a relatively short time to be an international centre for laser theory, starting in 1960 when Theodore Maiman built the first experimental laser. The interpretation of the laser principle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Self-organization
Self-organization, also called spontaneous order in the social sciences, is a process where some form of overall order arises from local interactions between parts of an initially disordered system. The process can be spontaneous when sufficient energy is available, not needing control by any external agent. It is often triggered by seemingly random fluctuations, amplified by positive feedback. The resulting organization is wholly decentralized, distributed over all the components of the system. As such, the organization is typically robust and able to survive or self-repair substantial perturbation. Chaos theory discusses self-organization in terms of islands of predictability in a sea of chaotic unpredictability. Self-organization occurs in many physical, chemical, biological, robotic, and cognitive systems. Examples of self-organization include crystallization, thermal convection of fluids, chemical oscillation, animal swarming, neural circuits, and black markets. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Multistability
In a dynamical system, multistability is the property of having multiple stable equilibrium points in the vector space spanned by the states in the system. By mathematical necessity, there must also be unstable equilibrium points between the stable points. Points that are stable in some dimensions and unstable in others are termed unstable, as is the case with the first three Lagrangian points. Bistability Bistability is the special case with two stable equilibrium points. It is the simplest form of multistability, and can occur in systems with only one state variable, as it only takes a one-dimensional space to separate two points. Initial instability Near an unstable equilibrium, any system will be sensitive to noise, initial conditions and system parameters, which can cause it to develop in one of multiple divergent directions. In economics and social sciences, path dependence gives rise to divergent directions of development. Some path dependent processes are adequately ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phase Transition
In chemistry, thermodynamics, and other related fields, a phase transition (or phase change) is the physical process of transition between one state of a medium and another. Commonly the term is used to refer to changes among the basic states of matter: solid, liquid, and gas, and in rare cases, plasma. A phase of a thermodynamic system and the states of matter have uniform physical properties. During a phase transition of a given medium, certain properties of the medium change as a result of the change of external conditions, such as temperature or pressure. This can be a discontinuous change; for example, a liquid may become gas upon heating to its boiling point, resulting in an abrupt change in volume. The identification of the external conditions at which a transformation occurs defines the phase transition point. Types of phase transition At the phase transition point for a substance, for instance the boiling point, the two phases involved - liquid and vapor, have ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FMRI
Functional magnetic resonance imaging or functional MRI (fMRI) measures brain activity by detecting changes associated with blood flow. This technique relies on the fact that cerebral blood flow and neuronal activation are coupled. When an area of the brain is in use, blood flow to that region also increases. The primary form of fMRI uses the blood-oxygen-level dependent (BOLD) contrast, discovered by Seiji Ogawa in 1990. This is a type of specialized brain and body scan used to map neural activity in the brain or spinal cord of humans or other animals by imaging the change in blood flow ( hemodynamic response) related to energy use by brain cells. Since the early 1990s, fMRI has come to dominate brain mapping research because it does not involve the use of injections, surgery, the ingestion of substances, or exposure to ionizing radiation. This measure is frequently corrupted by noise from various sources; hence, statistical procedures are used to extract the underlying signal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neural Circuitry
Artificial neural networks (ANNs), usually simply called neural networks (NNs) or neural nets, are computing systems inspired by the biological neural networks that constitute animal brains. An ANN is based on a collection of connected units or nodes called artificial neurons, which loosely model the neurons in a biological brain. Each connection, like the synapses in a biological brain, can transmit a signal to other neurons. An artificial neuron receives signals then processes them and can signal neurons connected to it. The "signal" at a connection is a real number, and the output of each neuron is computed by some non-linear function of the sum of its inputs. The connections are called ''edges''. Neurons and edges typically have a ''weight'' that adjusts as learning proceeds. The weight increases or decreases the strength of the signal at a connection. Neurons may have a threshold such that a signal is sent only if the aggregate signal crosses that threshold. Typically, n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Excitator Model
From the Latin for "to arouse," the excitator in Roman Catholic seminaries, monasteries and convents was the member of the community charged with the job of awakening community members each morning.Consuetudinarium Provinciae Marylandiensis-Neo Eboracensis Societatis Jesu Traditionally, the excitator (who usually held this post temporarily, as one of the community "chores" through which members would rotate) would knock on a bedroom door or open it slightly and loudly say, ''Benedicamus Domino!'' (Let us bless the Lord.) He or she was then to wait for the reply, ''Deo gratias!'' (Thanks be to God), which signaled that the occupant was now awake. Some communities maintain the tradition, while others now have members rely on their own alarm clock An alarm clock (or sometimes just an alarm) is a clock that is designed to alert an individual or group of individuals at a specified time. The primary function of these clocks is to awaken people from their night's sleep or short naps ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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