The mechanoreceptors of the costo-vertebral joints

PubMed Central

Godwin-Austen, R. B.

1969-01-01

1. Unitary recording in the thoracic dorsal roots of mechanoreceptor discharges from the costo-vertebral joints was carried out in the cat and rabbit. Criteria for the identification of costo-vertebral joint mechanoreceptors were established. 2. The majority of rib joint mechanoreceptors are slowly adapting and fifty-three such receptors were studied. Five rapidly adapting receptors were also identified. 3. The responses of these receptors have been correlated with rib position and movement. The slowly adapting receptors gave a monotonic response to different rib positions. 72% showed an increase of discharge rate with displacements towards expiratory rib positions. 4. In response to manually imposed rib movements slowly adapting joint mechanoreceptors gave a dynamic response which was directly related to the velocity of the movement and adapted within 2 sec. The movements of breathing produced a corresponding alteration of the discharge frequency of the slowly adapting receptors. 5. Slowly adapting receptors were localized to the capsule of the costo-transverse joint by probing. They responded to increased intra-articular pressure with an increase of discharge rate and were silenced by intra-articular lignocaine, 0·4%. 6. Rapidly adapting joint mechanoreceptors responded to rib movement with a brief burst of discharges. 7. The rib joint mechanoreceptors signal rib joint position, and the direction and velocity of rib movement. It is suggested that these afferent discharges provide the basis for the perception of respiratory movements of the chest. The significance of these receptors to the `sense of effort' resulting from a resistance to breathing is discussed. PMID:5789947

Multiscale biomechanical responses of adapted bone-periodontal ligament-tooth fibrous joints

PubMed Central

Jang, Andrew T.; Merkle, Arno; Fahey, Kevin; Gansky, Stuart A.; Ho, Sunita P.

2015-01-01

Reduced functional loads cause adaptations in organs. In this study, temporal adaptations of bone-ligament-tooth fibrous joints to reduced functional loads were mapped using a holistic approach. Systematic studies were performed to evaluate organ-level and tissue-level adaptations in specimens harvested periodically from rats given powder food for 6 months (N = 60 over 8,12,16,20, and 24 weeks). Bone-periodontal ligament (PDL)-tooth fibrous joint adaptation was evaluated by comparing changes in joint stiffness with changes in functional space between the tooth and alveolar bony socket. Adaptations in tissues included mapping changes in the PDL and bone architecture as observed from collagen birefringence, bone hardness and volume fraction in rats fed soft foods (soft diet, SD) compared to those fed hard pellets as a routine diet (hard diet, HD). In situ biomechanical testing on harvested fibrous joints revealed increased stiffness in SD groups (SD:239-605 N/mm) (p<0.05) at 8 and 12 weeks. Increased joint stiffness in early development phase was due to decreased functional space (at 8wks change in functional space was −33 µm, at 12wks change in functional space was −30 µm) and shifts in tissue quality as highlighted by birefringence, architecture and hardness. These physical changes were not observed in joints that were well into function, that is, in rodents older than 12 weeks of age. Significant adaptations in older groups were highlighted by shifts in bone growth (bone volume fraction 24wks: Δ-0.06) and bone hardness (8wks: Δ−0.04 GPa, 16 wks: Δ−0.07 GPa, 24wks: Δ−0.06 GPa). The response rate (N/s) of joints to mechanical loads decreased in SD groups. Results from the study showed that joint adaptation depended on age. The initial form-related adaptation (observed change in functional space) can challenge strain-adaptive nature of tissues to meet functional demands with increasing age into adulthood. The coupled effect between functional space in the bone-PDLtooth complex and strain-adaptive nature of tissues is necessary to accommodate functional demands, and is temporally sensitive despite joint malfunction. From an applied science perspective, we propose that adaptations are registered as functional history in tissues and joints. PMID:26151121

Adaptive independent joint control of manipulators - Theory and experiment

NASA Technical Reports Server (NTRS)

Seraji, H.

1988-01-01

The author presents a simple decentralized adaptive control scheme for multijoint robot manipulators based on the independent joint control concept. The proposed control scheme for each joint consists of a PID (proportional integral and differential) feedback controller and a position-velocity-acceleration feedforward controller, both with adjustable gains. The static and dynamic couplings that exist between the joint motions are compensated by the adaptive independent joint controllers while ensuring trajectory tracking. The proposed scheme is implemented on a MicroVAX II computer for motion control of the first three joints of a PUMA 560 arm. Experimental results are presented to demonstrate that trajectory tracking is achieved despite strongly coupled, highly nonlinear joint dynamics. The results confirm that the proposed decentralized adaptive control of manipulators is feasible, in spite of strong interactions between joint motions. The control scheme presented is computationally very fast and is amenable to parallel processing implementation within a distributed computing architecture, where each joint is controlled independently by a simple algorithm on a dedicated microprocessor.

Fiber-wireless integrated mobile backhaul network based on a hybrid millimeter-wave and free-space-optics architecture with an adaptive diversity combining technique.

PubMed

Zhang, Junwen; Wang, Jing; Xu, Yuming; Xu, Mu; Lu, Feng; Cheng, Lin; Yu, Jianjun; Chang, Gee-Kung

2016-05-01

We propose and experimentally demonstrate a novel fiber-wireless integrated mobile backhaul network based on a hybrid millimeter-wave (MMW) and free-space-optics (FSO) architecture using an adaptive combining technique. Both 60 GHz MMW and FSO links are demonstrated and fully integrated with optical fibers in a scalable and cost-effective backhaul system setup. Joint signal processing with an adaptive diversity combining technique (ADCT) is utilized at the receiver side based on a maximum ratio combining algorithm. Mobile backhaul transportation of 4-Gb/s 16 quadrature amplitude modulation frequency-division multiplexing (QAM-OFDM) data is experimentally demonstrated and tested under various weather conditions synthesized in the lab. Performance improvement in terms of reduced error vector magnitude (EVM) and enhanced link reliability are validated under fog, rain, and turbulence conditions.

Top-Down Visual Saliency via Joint CRF and Dictionary Learning.

PubMed

Yang, Jimei; Yang, Ming-Hsuan

2017-03-01

Top-down visual saliency is an important module of visual attention. In this work, we propose a novel top-down saliency model that jointly learns a Conditional Random Field (CRF) and a visual dictionary. The proposed model incorporates a layered structure from top to bottom: CRF, sparse coding and image patches. With sparse coding as an intermediate layer, CRF is learned in a feature-adaptive manner; meanwhile with CRF as the output layer, the dictionary is learned under structured supervision. For efficient and effective joint learning, we develop a max-margin approach via a stochastic gradient descent algorithm. Experimental results on the Graz-02 and PASCAL VOC datasets show that our model performs favorably against state-of-the-art top-down saliency methods for target object localization. In addition, the dictionary update significantly improves the performance of our model. We demonstrate the merits of the proposed top-down saliency model by applying it to prioritizing object proposals for detection and predicting human fixations.

In-home networks integrating high-capacity DMT data and DVB-T over large-core GI-POF.

PubMed

Beltrán, Marta; Shi, Yan; Okonkwo, Chigo; Llorente, Roberto; Tangdiongga, Eduward; Koonen, Ton

2012-12-31

The low-cost in-home distribution of full-standard digital TV jointly with high-bitrate data using 50 m long 1 mm core diameter graded-index plastic optical fiber (GI-POF) is proposed and experimentally demonstrated. Discrete multitone (DMT) modulation is demonstrated to provide an adaptive bitrate which can spectrally coexist with digital video broadcasting-terrestrial (DVB-T) signals in 470-862 MHz. A 3 Gb/s DMT signal and two DVB-T channels are generated, transmitted and received exhibiting excellent performance.

Joint Optimization of Fluence Field Modulation and Regularization in Task-Driven Computed Tomography.

PubMed

Gang, G J; Siewerdsen, J H; Stayman, J W

2017-02-11

This work presents a task-driven joint optimization of fluence field modulation (FFM) and regularization in quadratic penalized-likelihood (PL) reconstruction. Conventional FFM strategies proposed for filtered-backprojection (FBP) are evaluated in the context of PL reconstruction for comparison. We present a task-driven framework that leverages prior knowledge of the patient anatomy and imaging task to identify FFM and regularization. We adopted a maxi-min objective that ensures a minimum level of detectability index ( d' ) across sample locations in the image volume. The FFM designs were parameterized by 2D Gaussian basis functions to reduce dimensionality of the optimization and basis function coefficients were estimated using the covariance matrix adaptation evolutionary strategy (CMA-ES) algorithm. The FFM was jointly optimized with both space-invariant and spatially-varying regularization strength ( β ) - the former via an exhaustive search through discrete values and the latter using an alternating optimization where β was exhaustively optimized locally and interpolated to form a spatially-varying map. The optimal FFM inverts as β increases, demonstrating the importance of a joint optimization. For the task and object investigated, the optimal FFM assigns more fluence through less attenuating views, counter to conventional FFM schemes proposed for FBP. The maxi-min objective homogenizes detectability throughout the image and achieves a higher minimum detectability than conventional FFM strategies. The task-driven FFM designs found in this work are counter to conventional patterns for FBP and yield better performance in terms of the maxi-min objective, suggesting opportunities for improved image quality and/or dose reduction when model-based reconstructions are applied in conjunction with FFM.

The payload canister leaves the O&C with the Joint Airlock Module inside

NASA Technical Reports Server (NTRS)

2000-01-01

The payload canister, with the Joint Airlock Module inside, backs out of the Operations and Checkout Building for a short trip to the Space Station Processing Facility. There the module will undergo more preflight processing for the STS-104 mission scheduled for launch aboard Space Shuttle Atlantis May 17, 2001. The Joint Airlock Module is the gateway from which crew members aboard the International Space Station will enter and exit the 470-ton orbiting research facility.

Nuclear Technology. Course 28: Welding Inspection. Module 28-4, Weld Joint Verification.

ERIC Educational Resources Information Center

Espy, John

This fourth in a series of ten modules for a course titled Welding Inspection discusses the nomenclature, symbols, and the purposes of most common joint designs, preparations, and fit-ups. The module follows a typical format that includes the following sections: (1) introduction, (2) module prerequisites, (3) objectives, (4) notes to…

The Joint Airlock Module is moved to a payload canister in the O&C

NASA Technical Reports Server (NTRS)

2000-01-01

The Joint Airlock Module is suspended by an overhead crane in the Operations and Checkout Building before being moved and placed into the payload canister for transfer to the Space Station Processing Facility. There the module will undergo more preflight processing for the STS-104 mission scheduled for launch aboard Space Shuttle Atlantis May 17, 2001. The Joint Airlock Module is the gateway from which crew members aboard the International Space Station will enter and exit the 470-ton orbiting research facility.

Analysis of Hand and Wrist Postural Synergies in Tolerance Grasping of Various Objects

PubMed Central

Liu, Yuan; Jiang, Li; Yang, Dapeng; Liu, Hong

2016-01-01

Human can successfully grasp various objects in different acceptable relative positions between human hand and objects. This grasp functionality can be described as the grasp tolerance of human hand, which is a significant functionality of human grasp. To understand the motor control of human hand completely, an analysis of hand and wrist postural synergies in tolerance grasping of various objects is needed. Ten healthy right-handed subjects were asked to perform the tolerance grasping with right hand using 6 objects of different shapes, sizes and relative positions between human hand and objects. Subjects were wearing CyberGlove attaching motion tracker on right hand, allowing a measurement of the hand and wrist postures. Correlation analysis of joints and inter-joint/inter-finger modules were carried on to explore the coordination between joints or modules. As the correlation between hand and wrist module is not obvious in tolerance grasping, individual analysis of wrist synergies would be more practical. In this case, postural synergies of hand and wrist were then presented separately through principal component analysis (PCA), expressed through the principal component (PC) information transmitted ratio, PC elements distribution and reconstructed angle error of joints. Results on correlation comparison of different module movements can be well explained by the influence factors of the joint movement correlation. Moreover, correlation analysis of joints and modules showed the wrist module had the lowest correlation among all inter-finger and inter-joint modules. Hand and wrist postures were both sufficient to be described by a few principal components. In terms of the PC elements distribution of hand postures, compared with previous investigations, there was a greater proportion of movement in the thumb joints especially the interphalangeal (IP) and opposition rotation (ROT) joint. The research could serve to a complete understanding of hand grasp, and the design, control of the anthropomorphic hand and wrist. PMID:27580298

E-Learning and North-South collaboration: the experience of two public health schools in France and Benin.

PubMed

Edouard, Guévart; Dominique, Billot; Moussiliou, Paraïso Noël; Francis, Guillemin; Khaled, Bessaoud; Serge, Briançon

2009-10-14

Distance learning (e-learning) can facilitate access to training. Yet few public health E-learning experiments have been reported; institutes in developing countries experience difficulties in establishing on-line curricula, while developed countries struggle with adapting existing curricula to realities on the ground. In 2005, two schools of public health, one in France and one in Benin, began collaborating through contact sessions organised for Nancy University distance-learning students. This experience gave rise to a partnership aimed at developing training materials for e-Learning for African students. The distance-learning public health course at Nancy teaches public health professionals through a module entitled "Health and Development." The module is specifically tailored for professionals from developing countries. To promote student-teacher exchanges, clarify content and supervise dissertations, contact sessions are organized in centres proximate and accessible to African students. The Benin Institute's main feature is residential team learning; distance-learning courses are currently being prepared. The two collaborating institutions have developed a joint distance-learning module geared toward developing countries. The collaboration provides for the development, diffusion, and joint delivery of teaching modules featuring issues that are familiar to African staff, gives the French Institute credibility in assessing research work produced, and enables modules on specific African issues and approaches to be put online. While E-learning is a viable educational option for public health professionals, periodic contact can be advantageous. Our analysis showed that the benefit of the collaboration between the two institutions is mutual; the French Institute extends its geographical, cultural and contextual reach and expands its pool of teaching staff. The Benin Institute benefits from the technical partnership and expertise, which allow it to offer distance learning for Africa-specific contexts and applications.

Design of a knee joint mechanism that adapts to individual physiology.

PubMed

Jiun-Yih Kuan; Pasch, Kenneth A; Herr, Hugh M

2014-01-01

This paper describes the design of a new knee joint mechanism, called the Adaptive Coupling Joint (ACJ). The new mechanism has an adaptive trajectory of the center of rotations (COR) that automatically matches those of the attached biological joint. The detailed design is presented as well as characterization results of the ACJ. Conventional exoskeleton and assistive devices usually consider limb joints as a one to three degrees of freedom (DOFs) joint synthesized by multiple one-DOF hinge joints in a single plane. However, the biological joints are complex and usually rotate with respect to a changing COR. As a result, the mismatch between limb joint motion and mechanical interface motion can lead to forces that cause undesired ligament and muscle length changes and internal mechanical changes. These undesired changes contribute to discomfort, as well as to the slippage and sluggish interaction between humans and devices. It is shown that the ACJ can transmit planetary torques from either active or passive devices to the limbs without altering the normal biological joint motion.

Joint Acoustic and Modulation Frequency

NASA Astrophysics Data System (ADS)

Atlas, Les; Shamma, Shihab A.

2003-12-01

There is a considerable evidence that our perception of sound uses important features which is related to underlying signal modulations. This topic has been studied extensively via perceptual experiments, yet there are few, if any, well-developed signal processing methods which capitalize on or model these effects. We begin by summarizing evidence of the importance of modulation representations from psychophysical, physiological, and other sources. The concept of a two-dimensional joint acoustic and modulation frequency representation is proposed. A simple single sinusoidal amplitude modulator of a sinusoidal carrier is then used to illustrate properties of an unconstrained and ideal joint representation. Added constraints are required to remove or reduce undesired interference terms and to provide invertibility. It is then noted that the constraints would also apply to more general and complex cases of broader modulation and carriers. Applications in single-channel speaker separation and in audio coding are used to illustrate the applicability of this joint representation. Other applications in signal analysis and filtering are suggested.

KSC-01pp0872

NASA Image and Video Library

2001-03-19

KENNEDY SPACE CENTER, FLA. -- Members of the STS-104 crew look over equipment inside the equipment lock component of the Joint Airlock Module. At left is Mission Specialist Janet L. Kavandi, and at right Pilot Charles O. Hobaugh. The crew is at KSC to take part in Crew Equipment Interface Test activities. The mission will carry the Joint Airlock Module to the International Space Station. The U.S.-made module will allow astronauts and cosmonauts in residence on the Station to perform future spacewalks without the presence of a Space Shuttle. The module, which also comprises a crew lock, will be connected to the starboard (right) side of Node 1 Unity. Atlantis will also carry oxygen and nitrogen storage tanks, vital to operation of the Joint Airlock, on a Spacelab Logistics Double Pallet in the payload bay. The tanks, to be installed on the perimeter of the Joint Module during the mission’s spacewalks, will support future spacewalk operations and experiments plus augment the resupply system for the Station’s Service Module

KSC-01pp0871

NASA Image and Video Library

2001-03-19

KENNEDY SPACE CENTER, FLA. -- Members of the STS-104 crew look over equipment inside the equipment lock component of the Joint Airlock Module. At left is Mission Specialist Janet L. Kavandi, and at right Pilot Charles O. Hobaugh. The crew is at KSC to take part in Crew Equipment Interface Test activities. The mission will carry the Joint Airlock Module to the International Space Station. The U.S.-made module will allow astronauts and cosmonauts in residence on the Station to perform future spacewalks without the presence of a Space Shuttle. The module, which also comprises a crew lock, will be connected to the starboard (right) side of Node 1 Unity. Atlantis will also carry oxygen and nitrogen storage tanks, vital to operation of the Joint Airlock, on a Spacelab Logistics Double Pallet in the payload bay. The tanks, to be installed on the perimeter of the Joint Module during the mission’s spacewalks, will support future spacewalk operations and experiments plus augment the resupply system for the Station’s Service Module

Joint Optimization of Fluence Field Modulation and Regularization in Task-Driven Computed Tomography

PubMed Central

Gang, G. J.; Siewerdsen, J. H.; Stayman, J. W.

2017-01-01

Purpose This work presents a task-driven joint optimization of fluence field modulation (FFM) and regularization in quadratic penalized-likelihood (PL) reconstruction. Conventional FFM strategies proposed for filtered-backprojection (FBP) are evaluated in the context of PL reconstruction for comparison. Methods We present a task-driven framework that leverages prior knowledge of the patient anatomy and imaging task to identify FFM and regularization. We adopted a maxi-min objective that ensures a minimum level of detectability index (d′) across sample locations in the image volume. The FFM designs were parameterized by 2D Gaussian basis functions to reduce dimensionality of the optimization and basis function coefficients were estimated using the covariance matrix adaptation evolutionary strategy (CMA-ES) algorithm. The FFM was jointly optimized with both space-invariant and spatially-varying regularization strength (β) - the former via an exhaustive search through discrete values and the latter using an alternating optimization where β was exhaustively optimized locally and interpolated to form a spatially-varying map. Results The optimal FFM inverts as β increases, demonstrating the importance of a joint optimization. For the task and object investigated, the optimal FFM assigns more fluence through less attenuating views, counter to conventional FFM schemes proposed for FBP. The maxi-min objective homogenizes detectability throughout the image and achieves a higher minimum detectability than conventional FFM strategies. Conclusions The task-driven FFM designs found in this work are counter to conventional patterns for FBP and yield better performance in terms of the maxi-min objective, suggesting opportunities for improved image quality and/or dose reduction when model-based reconstructions are applied in conjunction with FFM. PMID:28626290

Joint optimization of fluence field modulation and regularization in task-driven computed tomography

NASA Astrophysics Data System (ADS)

Gang, G. J.; Siewerdsen, J. H.; Stayman, J. W.

2017-03-01

Purpose: This work presents a task-driven joint optimization of fluence field modulation (FFM) and regularization in quadratic penalized-likelihood (PL) reconstruction. Conventional FFM strategies proposed for filtered-backprojection (FBP) are evaluated in the context of PL reconstruction for comparison. Methods: We present a task-driven framework that leverages prior knowledge of the patient anatomy and imaging task to identify FFM and regularization. We adopted a maxi-min objective that ensures a minimum level of detectability index (d') across sample locations in the image volume. The FFM designs were parameterized by 2D Gaussian basis functions to reduce dimensionality of the optimization and basis function coefficients were estimated using the covariance matrix adaptation evolutionary strategy (CMA-ES) algorithm. The FFM was jointly optimized with both space-invariant and spatially-varying regularization strength (β) - the former via an exhaustive search through discrete values and the latter using an alternating optimization where β was exhaustively optimized locally and interpolated to form a spatially-varying map. Results: The optimal FFM inverts as β increases, demonstrating the importance of a joint optimization. For the task and object investigated, the optimal FFM assigns more fluence through less attenuating views, counter to conventional FFM schemes proposed for FBP. The maxi-min objective homogenizes detectability throughout the image and achieves a higher minimum detectability than conventional FFM strategies. Conclusions: The task-driven FFM designs found in this work are counter to conventional patterns for FBP and yield better performance in terms of the maxi-min objective, suggesting opportunities for improved image quality and/or dose reduction when model-based reconstructions are applied in conjunction with FFM.

The adaptive nature of eye movements in linguistic tasks: how payoff and architecture shape speed-accuracy trade-offs.

PubMed

Lewis, Richard L; Shvartsman, Michael; Singh, Satinder

2013-07-01

We explore the idea that eye-movement strategies in reading are precisely adapted to the joint constraints of task structure, task payoff, and processing architecture. We present a model of saccadic control that separates a parametric control policy space from a parametric machine architecture, the latter based on a small set of assumptions derived from research on eye movements in reading (Engbert, Nuthmann, Richter, & Kliegl, 2005; Reichle, Warren, & McConnell, 2009). The eye-control model is embedded in a decision architecture (a machine and policy space) that is capable of performing a simple linguistic task integrating information across saccades. Model predictions are derived by jointly optimizing the control of eye movements and task decisions under payoffs that quantitatively express different desired speed-accuracy trade-offs. The model yields distinct eye-movement predictions for the same task under different payoffs, including single-fixation durations, frequency effects, accuracy effects, and list position effects, and their modulation by task payoff. The predictions are compared to-and found to accord with-eye-movement data obtained from human participants performing the same task under the same payoffs, but they are found not to accord as well when the assumptions concerning payoff optimization and processing architecture are varied. These results extend work on rational analysis of oculomotor control and adaptation of reading strategy (Bicknell & Levy, ; McConkie, Rayner, & Wilson, 1973; Norris, 2009; Wotschack, 2009) by providing evidence for adaptation at low levels of saccadic control that is shaped by quantitatively varying task demands and the dynamics of processing architecture. Copyright © 2013 Cognitive Science Society, Inc.

Adaptive torque estimation of robot joint with harmonic drive transmission

NASA Astrophysics Data System (ADS)

Shi, Zhiguo; Li, Yuankai; Liu, Guangjun

2017-11-01

Robot joint torque estimation using input and output position measurements is a promising technique, but the result may be affected by the load variation of the joint. In this paper, a torque estimation method with adaptive robustness and optimality adjustment according to load variation is proposed for robot joint with harmonic drive transmission. Based on a harmonic drive model and a redundant adaptive robust Kalman filter (RARKF), the proposed approach can adapt torque estimation filtering optimality and robustness to the load variation by self-tuning the filtering gain and self-switching the filtering mode between optimal and robust. The redundant factor of RARKF is designed as a function of the motor current for tolerating the modeling error and load-dependent filtering mode switching. The proposed joint torque estimation method has been experimentally studied in comparison with a commercial torque sensor and two representative filtering methods. The results have demonstrated the effectiveness of the proposed torque estimation technique.

[Advanced Development for Space Robotics With Emphasis on Fault Tolerance Technology

NASA Technical Reports Server (NTRS)

Tesar, Delbert

1997-01-01

This report describes work developing fault tolerant redundant robotic architectures and adaptive control strategies for robotic manipulator systems which can dynamically accommodate drastic robot manipulator mechanism, sensor or control failures and maintain stable end-point trajectory control with minimum disturbance. Kinematic designs of redundant, modular, reconfigurable arms for fault tolerance were pursued at a fundamental level. The approach developed robotic testbeds to evaluate disturbance responses of fault tolerant concepts in robotic mechanisms and controllers. The development was implemented in various fault tolerant mechanism testbeds including duality in the joint servo motor modules, parallel and serial structural architectures, and dual arms. All have real-time adaptive controller technologies to react to mechanism or controller disturbances (failures) to perform real-time reconfiguration to continue the task operations. The developments fall into three main areas: hardware, software, and theoretical.

Virtual trajectories, joint stiffness, and changes in the limb natural frequency during single-joint oscillatory movements.

PubMed

Latash, M L

1992-07-01

In the framework of the equilibrium-point hypothesis, virtual trajectories and patterns of joint stiffness were reconstructed during voluntary single-joint oscillatory movements in the elbow joint at a variety of frequencies and against two inertial loads. At low frequencies, virtual trajectories were in-phase with the actual joint trajectories. Joint stiffness changed at a doubled frequency. An increase in movement frequency and/or inertial load led to an increase in the difference between the peaks of the actual and virtual trajectories and in both peak and averaged values of joint stiffness. At a certain, critical frequency, virtual trajectory was nearly flat. Further increase in movement frequency led to a 180 degree phase shift between the actual and virtual trajectories. The assessed values of the natural frequency of the system "limb + manipulandum" were close to the critical frequencies for both low and high inertial loads. Peak levels and integrals of the electromyograms of two flexor and two extensor muscles changed monotonically with movement frequency without any special behavior at the critical frequencies. Nearly flat virtual trajectories at the natural frequency make physical sense as hypothetical control signals, unlike the electromyographic recordings, since a system at its natural frequency requires minimal central interference. Modulation of joint stiffness is assumed to be an important adaptive mechanism attenuating difference between the system's natural frequency and desired movement frequency. Virtual trajectory is considered a behavioral observable. Phase transitions between the virtual and actual trajectories are illustrations of behavioral discontinuities introduced by slow changes in a higher level control parameter, movement frequency. Relative phase shift between these two trajectories may be considered an order parameter.

Decentralized adaptive control of manipulators - Theory, simulation, and experimentation

NASA Technical Reports Server (NTRS)

Seraji, Homayoun

1989-01-01

The author presents a simple decentralized adaptive-control scheme for multijoint robot manipulators based on the independent joint control concept. The control objective is to achieve accurate tracking of desired joint trajectories. The proposed control scheme does not use the complex manipulator dynamic model, and each joint is controlled simply by a PID (proportional-integral-derivative) feedback controller and a position-velocity-acceleration feedforward controller, both with adjustable gains. Simulation results are given for a two-link direct-drive manipulator under adaptive independent joint control. The results illustrate trajectory tracking under coupled dynamics and varying payload. The proposed scheme is implemented on a MicroVAX II computer for motion control of the three major joints of a PUMA 560 arm. Experimental results are presented to demonstrate that trajectory tracking is achieved despite coupled nonlinear joint dynamics.

Advanced techniques and technology for efficient data storage, access, and transfer

NASA Technical Reports Server (NTRS)

Rice, Robert F.; Miller, Warner

1991-01-01

Advanced techniques for efficiently representing most forms of data are being implemented in practical hardware and software form through the joint efforts of three NASA centers. These techniques adapt to local statistical variations to continually provide near optimum code efficiency when representing data without error. Demonstrated in several earlier space applications, these techniques are the basis of initial NASA data compression standards specifications. Since the techniques clearly apply to most NASA science data, NASA invested in the development of both hardware and software implementations for general use. This investment includes high-speed single-chip very large scale integration (VLSI) coding and decoding modules as well as machine-transferrable software routines. The hardware chips were tested in the laboratory at data rates as high as 700 Mbits/s. A coding module's definition includes a predictive preprocessing stage and a powerful adaptive coding stage. The function of the preprocessor is to optimally process incoming data into a standard form data source that the second stage can handle.The built-in preprocessor of the VLSI coder chips is ideal for high-speed sampled data applications such as imaging and high-quality audio, but additionally, the second stage adaptive coder can be used separately with any source that can be externally preprocessed into the 'standard form'. This generic functionality assures that the applicability of these techniques and their recent high-speed implementations should be equally broad outside of NASA.

Defense Acquisition and the Case of the Joint Capabilities Technology Demonstration Office: Ad Hoc Problem Solving as a Mechanism for Adaptive Change

DTIC Science & Technology

2013-10-01

pmlkploba=obmloq=pbofbp= Defense Acquisition and the Case of the Joint Capabilities Technology Demonstration Office: Ad Hoc Problem Solving as a...of the Joint Capabilities Technology Demonstration Office: Ad Hoc Problem Solving as a Mechanism for Adaptive Change 5a. CONTRACT NUMBER 5b. GRANT...findings of our study exploring what drives successful organizational adaptation in the context of technology transition and acquisition within the

Decentralized digital adaptive control of robot motion

NASA Technical Reports Server (NTRS)

Tarokh, M.

1990-01-01

A decentralized model reference adaptive scheme is developed for digital control of robot manipulators. The adaptation laws are derived using hyperstability theory, which guarantees asymptotic trajectory tracking despite gross robot parameter variations. The control scheme has a decentralized structure in the sense that each local controller receives only its joint angle measurement to produce its joint torque. The independent joint controllers have simple structures and can be programmed using a very simple and computationally fast algorithm. As a result, the scheme is suitable for real-time motion control.

Establishment of joint attention in dyads involving hearing mothers of deaf and hearing children, and its relation to adaptive social behavior.

PubMed

Nowakowski, Matilda E; Tasker, Susan L; Schmidt, Louis A

2009-01-01

Mounting evidence points to joint attention as a mediating variable in children's adaptive behavior development. Joint attention in interactions between hearing mothers and congenitally deaf (n = 27) and hearing (n = 29) children, ages 18-36 months, was examined. All deaf children had severe to profound hearing loss. Mother-child interactions were coded for maternally initiated and child-initiated success rates in establishing joint attention; mothers completed ratings of their children's adaptive behavior. Hearing mother-deaf child dyads had significantly lower maternally initiated success rates. No significant between-group differences on child-initiated success rates were shown. Maternal ratings of adaptive behavior were significantly lower for deaf children, and related positively and significantly to both child-initiated and maternally initiated success rates. The findings suggest that mother-child interactions that are low in successful establishment of joint attention might mediate the development of socioemotional problems evident in deaf children with hearing families.

Joint-space adaptive control of a 6 DOF end-effector with closed-kinematic chain mechanism

NASA Technical Reports Server (NTRS)

Nguyen, Charles C.; Zhou, Zhen-Lei

1989-01-01

The development is presented for a joint-space adaptive scheme that controls the joint position of a six-degree-of-freedom (DOF) robot end-effector performing fine and precise motion within a very limited workspace. The end-effector was built to study autonomous assembly of NASA hardware in space. The design of the adaptive controller is based on the concept of model reference adaptive control (MRAC) and Lyapunov direct method. In the development, it is assumed that the end-effector performs slowly varying motion. Computer simulation is performed to investigate the performance of the developed control scheme on position control of the end-effector. Simulation results manifest that the adaptive control scheme provides excellent tracking of several test paths.

Variable Cadence Walking and Ground Adaptive Standing with a Powered Ankle Prosthesis

PubMed Central

Shultz, Amanda H.; Lawson, Brian E.; Goldfarb, Michael

2015-01-01

Abstract This paper describes a control approach that provides walking and standing functionality for a powered ankle prosthesis, and demonstrates the efficacy of the approach in experiments in which a unilateral transtibial amputee subject walks with the prosthesis at variable cadences, and stands on various slopes. Both controllers incorporate a finite-state structure that emulates healthy ankle joint behavior via a series of piecewise passive impedance functions. The walking controller incorporates an algorithm to modify impedance parameters based on estimated cadence, while the standing controller incorporates an algorithm to modulate the ankle equilibrium angle in order to adapt to the ground slope and user posture, and the supervisory controller selects between the walking and standing controllers. The system is shown to reproduce several essential biomechanical features of the healthy joint during walking, particularly relative to a passive prosthesis, and is shown to adapt to variable cadences. The system is also shown to adapt to slopes over a range of ± 15 deg and to provide support to the user in a manner that is biomimetic, as validated by quasi-static stiffness measurements recorded by the prosthesis. Data from standing trials indicate that the user places more weight on the powered prosthesis than on his passive prosthesis when standing on sloped surfaces, particularly at angles of 10 deg or greater. The authors also demonstrated that the prosthesis typically began providing support within 1 s of initial contact with the ground. Further, the supervisory controller was shown to be effective in switching between walking and standing, as well as in determining ground slope just prior to the transition from the standing controller to the walking controller, where the estimated ground slope was within 1.25 deg of the actual ground slope for all trials. PMID:25955789

Direct adaptive control of a PUMA 560 industrial robot

NASA Technical Reports Server (NTRS)

Seraji, Homayoun; Lee, Thomas; Delpech, Michel

1989-01-01

The implementation and experimental validation of a new direct adaptive control scheme on a PUMA 560 industrial robot is described. The testbed facility consists of a Unimation PUMA 560 six-jointed robot and controller, and a DEC MicroVAX II computer which hosts the Robot Control C Library software. The control algorithm is implemented on the MicroVAX which acts as a digital controller for the PUMA robot, and the Unimation controller is effectively bypassed and used merely as an I/O device to interface the MicroVAX to the joint motors. The control algorithm for each robot joint consists of an auxiliary signal generated by a constant-gain Proportional plus Integral plus Derivative (PID) controller, and an adaptive position-velocity (PD) feedback controller with adjustable gains. The adaptive independent joint controllers compensate for the inter-joint couplings and achieve accurate trajectory tracking without the need for the complex dynamic model and parameter values of the robot. Extensive experimental results on PUMA joint control are presented to confirm the feasibility of the proposed scheme, in spite of strong interactions between joint motions. Experimental results validate the capabilities of the proposed control scheme. The control scheme is extremely simple and computationally very fast for concurrent processing with high sampling rates.

Discriminative clustering on manifold for adaptive transductive classification.

PubMed

Zhang, Zhao; Jia, Lei; Zhang, Min; Li, Bing; Zhang, Li; Li, Fanzhang

2017-10-01

In this paper, we mainly propose a novel adaptive transductive label propagation approach by joint discriminative clustering on manifolds for representing and classifying high-dimensional data. Our framework seamlessly combines the unsupervised manifold learning, discriminative clustering and adaptive classification into a unified model. Also, our method incorporates the adaptive graph weight construction with label propagation. Specifically, our method is capable of propagating label information using adaptive weights over low-dimensional manifold features, which is different from most existing studies that usually predict the labels and construct the weights in the original Euclidean space. For transductive classification by our formulation, we first perform the joint discriminative K-means clustering and manifold learning to capture the low-dimensional nonlinear manifolds. Then, we construct the adaptive weights over the learnt manifold features, where the adaptive weights are calculated through performing the joint minimization of the reconstruction errors over features and soft labels so that the graph weights can be joint-optimal for data representation and classification. Using the adaptive weights, we can easily estimate the unknown labels of samples. After that, our method returns the updated weights for further updating the manifold features. Extensive simulations on image classification and segmentation show that our proposed algorithm can deliver the state-of-the-art performance on several public datasets. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of joint attention on long-term memory in 9-month-old infants: an event-related potentials study.

PubMed

Kopp, Franziska; Lindenberger, Ulman

2011-07-01

Joint attention develops during the first year of life but little is known about its effects on long-term memory. We investigated whether joint attention modulates long-term memory in 9-month-old infants. Infants were familiarized with visually presented objects in either of two conditions that differed in the degree of joint attention (high versus low). EEG indicators in response to old and novel objects were probed directly after the familiarization phase (immediate recognition), and following a 1-week delay (delayed recognition). In immediate recognition, the amplitude of positive slow-wave activity was modulated by joint attention. In the delayed recognition, the amplitude of the Pb component differentiated between high and low joint attention. In addition, the positive slow-wave amplitude during immediate and delayed recognition correlated with the frequency of infants' looks to the experimenter during familiarization. Under both high- and low-joint-attention conditions, the processing of unfamiliar objects was associated with an enhanced Nc component. Our results show that the degree of joint attention modulates EEG during immediate and delayed recognition. We conclude that joint attention affects long-term memory processing in 9-month-old infants by enhancing the relevance of attended items. © 2010 Blackwell Publishing Ltd.

The Effect of Manipulating Subject Mass on Lower Extremity Torque Patterns During Locomotion

NASA Technical Reports Server (NTRS)

DeWitt, John K.; Cromwell, Ronita L.; Hagan, R. Donald

2007-01-01

During locomotion, humans adapt their motor patterns to maintain coordination despite changing conditions (Reisman et al., 2005). Bernstein (1967) proposed that in addition to the present state of a given joint, other factors, including limb inertia and velocity, must be taken into account to allow proper motion to occur. During locomotion with added mass counterbalanced using vertical suspension to maintain body weight, vertical ground reaction forces (GRF's) increase during walking but decrease during running, suggesting that adaptation may be velocity-specific (De Witt et al., 2006). It is not known, however, how lower extremity joint torques adapt to changes in inertial forces. The purpose of this investigation was to examine the effects of increasing body mass while maintaining body weight upon lower-limb joint torque during walking and running. We hypothesized that adaptations in joint torque patterns would occur with the addition of body mass.

Lunar Module 4 moved for mating with Lunar Module Adapter at KSC

NASA Technical Reports Server (NTRS)

1969-01-01

Lunar Module 4 in the Kennedy Space Center's Manned Spacecraft Operations Bldg being moved into position for mating with Spacecraft Lunar Module Adapter (SLA) 13 (17809);Lunar Module 4 being moved for mating with the Spacecraft Lunar Module Adapter in the Kennedy Space Center's (KSC) Manned Spacecraft Operations Building. Lunar module 4 will be flown on the Apollo 10 (Spacecraft 106/Saturn 505) lunar orbit mission (17810).

An Adaptive Neuromuscular Controller for Assistive Lower-Limb Exoskeletons: A Preliminary Study on Subjects with Spinal Cord Injury

PubMed Central

Wu, Amy R.; Dzeladini, Florin; Brug, Tycho J. H.; Tamburella, Federica; Tagliamonte, Nevio L.; van Asseldonk, Edwin H. F.; van der Kooij, Herman; Ijspeert, Auke J.

2017-01-01

Versatility is important for a wearable exoskeleton controller to be responsive to both the user and the environment. These characteristics are especially important for subjects with spinal cord injury (SCI), where active recruitment of their own neuromuscular system could promote motor recovery. Here we demonstrate the capability of a novel, biologically-inspired neuromuscular controller (NMC) which uses dynamical models of lower limb muscles to assist the gait of SCI subjects. Advantages of this controller include robustness, modularity, and adaptability. The controller requires very few inputs (i.e., joint angles, stance, and swing detection), can be decomposed into relevant control modules (e.g., only knee or hip control), and can generate walking at different speeds and terrains in simulation. We performed a preliminary evaluation of this controller on a lower-limb knee and hip robotic gait trainer with seven subjects (N = 7, four with complete paraplegia, two incomplete, one healthy) to determine if the NMC could enable normal-like walking. During the experiment, SCI subjects walked with body weight support on a treadmill and could use the handrails. With controller assistance, subjects were able to walk at fast walking speeds for ambulatory SCI subjects—from 0.6 to 1.4 m/s. Measured joint angles and NMC-provided joint torques agreed reasonably well with kinematics and biological joint torques of a healthy subject in shod walking. Some differences were found between the torques, such as the lack of knee flexion near mid-stance, but joint angle trajectories did not seem greatly affected. The NMC also adjusted its torque output to provide more joint work at faster speeds and thus greater joint angles and step length. We also found that the optimal speed-step length curve observed in healthy humans emerged for most of the subjects, albeit with relatively longer step length at faster speeds. Therefore, with very few sensors and no predefined settings for multiple walking speeds or adjustments for subjects of differing anthropometry and walking ability, NMC enabled SCI subjects to walk at several speeds, including near healthy speeds, in a healthy-like manner. These preliminary results are promising for future implementation of neuromuscular controllers on wearable prototypes for real-world walking conditions. PMID:28676752

An Adaptive Neuromuscular Controller for Assistive Lower-Limb Exoskeletons: A Preliminary Study on Subjects with Spinal Cord Injury.

PubMed

Wu, Amy R; Dzeladini, Florin; Brug, Tycho J H; Tamburella, Federica; Tagliamonte, Nevio L; van Asseldonk, Edwin H F; van der Kooij, Herman; Ijspeert, Auke J

2017-01-01

Versatility is important for a wearable exoskeleton controller to be responsive to both the user and the environment. These characteristics are especially important for subjects with spinal cord injury (SCI), where active recruitment of their own neuromuscular system could promote motor recovery. Here we demonstrate the capability of a novel, biologically-inspired neuromuscular controller (NMC) which uses dynamical models of lower limb muscles to assist the gait of SCI subjects. Advantages of this controller include robustness, modularity, and adaptability. The controller requires very few inputs (i.e., joint angles, stance, and swing detection), can be decomposed into relevant control modules (e.g., only knee or hip control), and can generate walking at different speeds and terrains in simulation. We performed a preliminary evaluation of this controller on a lower-limb knee and hip robotic gait trainer with seven subjects ( N = 7, four with complete paraplegia, two incomplete, one healthy) to determine if the NMC could enable normal-like walking. During the experiment, SCI subjects walked with body weight support on a treadmill and could use the handrails. With controller assistance, subjects were able to walk at fast walking speeds for ambulatory SCI subjects-from 0.6 to 1.4 m/s. Measured joint angles and NMC-provided joint torques agreed reasonably well with kinematics and biological joint torques of a healthy subject in shod walking. Some differences were found between the torques, such as the lack of knee flexion near mid-stance, but joint angle trajectories did not seem greatly affected. The NMC also adjusted its torque output to provide more joint work at faster speeds and thus greater joint angles and step length. We also found that the optimal speed-step length curve observed in healthy humans emerged for most of the subjects, albeit with relatively longer step length at faster speeds. Therefore, with very few sensors and no predefined settings for multiple walking speeds or adjustments for subjects of differing anthropometry and walking ability, NMC enabled SCI subjects to walk at several speeds, including near healthy speeds, in a healthy-like manner. These preliminary results are promising for future implementation of neuromuscular controllers on wearable prototypes for real-world walking conditions.

Adaptive plasticity in mammalian masticatory joints

NASA Astrophysics Data System (ADS)

Ravosa, Matthew J.; Kunwar, Ravinder; Nicholson, Elisabeth K.; Klopp, Emily B.; Pinchoff, Jessie; Stock, Stuart R.; Stack, M. Sharon; Hamrick, Mark W.

2006-08-01

Genetically similar white rabbits raised on diets of different mechanical properties, as well as wild-type and myostatin-deficient mice raised on similar diets, were compared to assess the postweaning effects of elevated masticatory loads due to increased jaw-adductor muscle and bite forces on the proportions and properties of the mandibular symphysis and temporomandibular joint (TMJ). Microcomputed tomography (microCT) was used to quantify bone structure at a series of equidistant external and internal sites in coronal sections for a series of joint locations. Discriminant function analyses and non-parametric ANOVAs were used to characterize variation in biomineralization within and between loading cohorts. In both species, long-term excessive loading results in larger joint proportions, thicker articular and cortical bone, and increased biomineralization of hard tissues. Such adaptive plasticity appears designed to maintain the postnatal integrity of masticatory joint systems for a primary loading environment(s). This behavioral signal may be increasingly mitigated in older organisms by the interplay between adaptive and degradative joint tissue responses.

Managing the risks of extreme events and disasters to advance climate change adaptation. Special report of the Intergovernmental Panel on Climate Change (IPCC)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Field, C.B.; Barros, V.; Stocker, T.F.

2012-07-01

This Special Report on Managing the Risks of Extreme Events and Disasters to Advance Climate Change Adaptation (SREX) has been jointly coordinated by Working Groups I (WGI) and II (WGII) of the Intergovernmental Panel on Climate Change (IPCC). The report focuses on the relationship between climate change and extreme weather and climate events, the impacts of such events, and the strategies to manage the associated risks. This Special Report, in particular, contributes to frame the challenge of dealing with extreme weather and climate events as an issue in decision making under uncertainty, analyzing response in the context of risk management.more » The report consists of nine chapters, covering risk management; observed and projected changes in extreme weather and climate events; exposure and vulnerability to as well as losses resulting from such events; adaptation options from the local to the international scale; the role of sustainable development in modulating risks; and insights from specific case studies. (LN)« less

Defense Acquisition and the Case of the Joint Capabilities Technology Demonstration Office: Ad Hoc Problem Solving as a Mechanism for Adaptive Change

DTIC Science & Technology

2013-04-01

Capabilities Technology Demonstration Office: Ad Hoc Problem Solving as a Mechanism for Adaptive Change Kathryn Aten and John T. Dillard Naval...Defense Acquisition and the Case of the Joint Capabilities Technology Demonstration Office: Ad Hoc Problem Solving as a Mechanism for Adaptive Change...describes the preliminary analysis and findings of our study exploring what drives successful organizational adaptation in the context of technology

CPG-inspired workspace trajectory generation and adaptive locomotion control for quadruped robots.

PubMed

Liu, Chengju; Chen, Qijun; Wang, Danwei

2011-06-01

This paper deals with the locomotion control of quadruped robots inspired by the biological concept of central pattern generator (CPG). A control architecture is proposed with a 3-D workspace trajectory generator and a motion engine. The workspace trajectory generator generates adaptive workspace trajectories based on CPGs, and the motion engine realizes joint motion imputes. The proposed architecture is able to generate adaptive workspace trajectories online by tuning the parameters of the CPG network to adapt to various terrains. With feedback information, a quadruped robot can walk through various terrains with adaptive joint control signals. A quadruped platform AIBO is used to validate the proposed locomotion control system. The experimental results confirm the effectiveness of the proposed control architecture. A comparison by experiments shows the superiority of the proposed method against the traditional CPG-joint-space control method.

Joint Mobilization Enhances Mechanisms of Conditioned Pain Modulation in Individuals With Osteoarthritis of the Knee.

PubMed

Courtney, Carol A; Steffen, Alana D; Fernández-de-Las-Peñas, César; Kim, John; Chmell, Samuel J

2016-03-01

An experimental laboratory study with a repeated-measures crossover design. Treatment effects of joint mobilization may occur in part by decreasing excitability of central nociceptive pathways. Impaired conditioned pain modulation (CPM) has been found experimentally in persons with knee and hip osteoarthritis, indicating impaired inhibition of central nociceptive pathways. We hypothesized increased effectiveness of CPM following application of joint mobilization, determined via measures of deep tissue hyperalgesia. To examine the effect of joint mobilization on impaired CPM. An examination of 40 individuals with moderate/severe knee osteoarthritis identified 29 (73%) with impaired CPM. The subjects were randomized to receive 6 minutes of knee joint mobilization (intervention) or manual cutaneous input only, 1 week apart. Deep tissue hyperalgesia was examined via pressure pain thresholds bilaterally at the knee medial joint line and the hand at baseline, postintervention, and post-CPM testing. Further, vibration perception threshold was measured at the medial knee epicondyle at baseline and post-CPM testing. Joint mobilization, but not cutaneous input intervention, resulted in a global increase in pressure pain threshold, indicated by diminished hyperalgesic responses to pressure stimulus. Further, CPM was significantly enhanced following joint mobilization. Diminished baseline vibration perception threshold acuity was enhanced following joint mobilization at the knee that received intervention, but not at the contralateral knee. Resting pain was also significantly lower following the joint intervention. Conditioned pain modulation was enhanced following joint mobilization, demonstrated by a global decrease in deep tissue pressure sensitivity. Joint mobilization may act via enhancement of descending pain mechanisms in patients with painful knee osteoarthritis.

Orion Crew Module Adapter

NASA Image and Video Library

2015-11-12

Offloading of the Orion Crew Module Adapter, CMA, at Plum Brook Station. The adapter will connect Orion’s crew module to a service module provided by ESA (European Space Agency). NASA is preparing for a series of tests that will check out the Orion European Service Module, a critical part of the spacecraft that will be launched on future missions to an asteroid and on toward Mars.

Adaptive Postural Control for Joint Immobilization during Multitask Performance

PubMed Central

Hsu, Wei-Li

2014-01-01

Motor abundance is an essential feature of adaptive control. The range of joint combinations enabled by motor abundance provides the body with the necessary freedom to adopt different positions, configurations, and movements that allow for exploratory postural behavior. This study investigated the adaptation of postural control to joint immobilization during multi-task performance. Twelve healthy volunteers (6 males and 6 females; 21–29 yr) without any known neurological deficits, musculoskeletal conditions, or balance disorders participated in this study. The participants executed a targeting task, alone or combined with a ball-balancing task, while standing with free or restricted joint motions. The effects of joint configuration variability on center of mass (COM) stability were examined using uncontrolled manifold (UCM) analysis. The UCM method separates joint variability into two components: the first is consistent with the use of motor abundance, which does not affect COM position (VUCM); the second leads to COM position variability (VORT). The analysis showed that joints were coordinated such that their variability had a minimal effect on COM position. However, the component of joint variability that reflects the use of motor abundance to stabilize COM (VUCM) was significant decreased when the participants performed the combined task with immobilized joints. The component of joint variability that leads to COM variability (VORT) tended to increase with a reduction in joint degrees of freedom. The results suggested that joint immobilization increases the difficulty of stabilizing COM when multiple tasks are performed simultaneously. These findings are important for developing rehabilitation approaches for patients with limited joint movements. PMID:25329477

Apparatus, Systems, and Methods for Reconfigurable Robotic Manipulator and Coupling

NASA Technical Reports Server (NTRS)

Chu, Mars Wei (Inventor); Wolfe, Bryn Tyler (Inventor); Burridge, Robert Raven (Inventor)

2016-01-01

A robotic manipulator arm is disclosed. The arm includes joints that are attachable and detachable in a tool-free manner via a universal mating adapter. The universal mating adapter includes a built-in electrical interface for an operative electrical connection upon mechanical coupling of the adapter portions. The universal mating adapter includes mechanisms and the ability to store and communicate parameter configurations such that the joints can be rearranged for immediate operation of the arm without further reprogramming, recompiling, or other software intervention.

Periodontal Ligament Entheses and their Adaptive Role in the Context of Dentoalveolar Joint Function

PubMed Central

Lin, Jeremy D.; Jang, Andrew T.; Kurylo, Michael P.; Hurng, Jonathan; Yang, Feifei; Yang, Lynn; Pal, Arvin; Chen, Ling; Ho, Sunita P.

2017-01-01

Objectives The dynamic bone-periodontal ligament (PDL)-tooth fibrous joint consists of two adaptive functionally graded interfaces (FGI), the PDL-bone and PDL-cementum that respond to mechanical strain transmitted during mastication. In general, from a materials and mechanics perspective, FGI prevent catastrophic failure during prolonged cyclic loading. This review is a discourse of results gathered from literature to illustrate the dynamic adaptive nature of the fibrous joint in response to physiologic and pathologic simulated functions, and experimental tooth movement. Methods Historically, studies have investigated soft to hard tissue transitions through analytical techniques that provided insights into structural, biochemical, and mechanical characterization methods. Experimental approaches included two dimensional to three dimensional advanced in situ imaging and analytical techniques. These techniques allowed mapping and correlation of deformations to physicochemical and mechanobiological changes within volumes of the complex subjected to concentric and eccentric loading regimes respectively. Results Tooth movement is facilitated by mechanobiological activity at the interfaces of the fibrous joint and generates elastic discontinuities at these interfaces in response to eccentric loading. Both concentric and eccentric loads mediated cellular responses to strains, and prompted self-regulating mineral forming and resorbing zones that in turn altered the functional space of the joint. Significance A multiscale biomechanics and mechanobiology approach is important for correlating joint function to tissue-level strain-adaptive properties with overall effects on joint form as related to physiologic and pathologic functions. Elucidating the shift in localization of biomolecules specifically at interfaces during development, function, and therapeutic loading of the joint is critical for developing “functional regeneration and adaptation” strategies with an emphasis on restoring physiologic joint function. PMID:28476202

Walk and roll robot

NASA Technical Reports Server (NTRS)

Wilson, Andrew (Inventor); Punnoose, Andrew (Inventor); Strausser, Katherine (Inventor); Parikh, Neil (Inventor)

2011-01-01

A mobile robotic unit features a main body, a plurality of legs for supporting the main body on and moving the main body in forward and reverse directions about a base surface, and a drive assembly. According to an exemplary embodiment each leg includes a respective pivotal hip joint, a pivotal knee joint, and a wheeled foot adapted to roll along the base surface. Also according to an exemplary embodiments the drive assembly includes a motor operatively associated with the hip and knee joints and the wheeled foot for independently driving pivotal movement of the hip joint and the knee joint and rolling motion of the wheeled foot. The hip joint may include a ball-and-socket-type joint interconnecting top portion of the leg to the main body, such that the hip joint is adapted to pivot said leg in a direction transverse to a forward-and-reverse direction.

Asymmetric Dual-Band Tracking Technique for Optimal Joint Processing of BDS B1I and B1C Signals

PubMed Central

Wang, Chuhan; Cui, Xiaowei; Ma, Tianyi; Lu, Mingquan

2017-01-01

Along with the rapid development of the Global Navigation Satellite System (GNSS), satellite navigation signals have become more diversified, complex, and agile in adapting to increasing market demands. Various techniques have been developed for processing multiple navigation signals to achieve better performance in terms of accuracy, sensitivity, and robustness. This paper focuses on a technique for processing two signals with separate but adjacent center frequencies, such as B1I and B1C signals in the BeiDou global system. The two signals may differ in modulation scheme, power, and initial phase relation and can be processed independently by user receivers; however, the propagation delays of the two signals from a satellite are nearly identical as they are modulated on adjacent frequencies, share the same reference clock, and undergo nearly identical propagation paths to the receiver, resulting in strong coherence between the two signals. Joint processing of these signals can achieve optimal measurement performance due to the increased Gabor bandwidth and power. In this paper, we propose a universal scheme of asymmetric dual-band tracking (ASYM-DBT) to take advantage of the strong coherence, the increased Gabor bandwidth, and power of the two signals in achieving much-reduced thermal noise and more accurate ranging results when compared with the traditional single-band algorithm. PMID:29035350

Asymmetric Dual-Band Tracking Technique for Optimal Joint Processing of BDS B1I and B1C Signals.

PubMed

Wang, Chuhan; Cui, Xiaowei; Ma, Tianyi; Zhao, Sihao; Lu, Mingquan

2017-10-16

Along with the rapid development of the Global Navigation Satellite System (GNSS), satellite navigation signals have become more diversified, complex, and agile in adapting to increasing market demands. Various techniques have been developed for processing multiple navigation signals to achieve better performance in terms of accuracy, sensitivity, and robustness. This paper focuses on a technique for processing two signals with separate but adjacent center frequencies, such as B1I and B1C signals in the BeiDou global system. The two signals may differ in modulation scheme, power, and initial phase relation and can be processed independently by user receivers; however, the propagation delays of the two signals from a satellite are nearly identical as they are modulated on adjacent frequencies, share the same reference clock, and undergo nearly identical propagation paths to the receiver, resulting in strong coherence between the two signals. Joint processing of these signals can achieve optimal measurement performance due to the increased Gabor bandwidth and power. In this paper, we propose a universal scheme of asymmetric dual-band tracking (ASYM-DBT) to take advantage of the strong coherence, the increased Gabor bandwidth, and power of the two signals in achieving much-reduced thermal noise and more accurate ranging results when compared with the traditional single-band algorithm.

[Analysis of the stability and adaptability of near infrared spectra qualitative analysis model].

PubMed

Cao, Wu; Li, Wei-jun; Wang, Ping; Zhang, Li-ping

2014-06-01

The stability and adaptability of model of near infrared spectra qualitative analysis were studied. Method of separate modeling can significantly improve the stability and adaptability of model; but its ability of improving adaptability of model is limited. Method of joint modeling can not only improve the adaptability of the model, but also the stability of model, at the same time, compared to separate modeling, the method can shorten the modeling time, reduce the modeling workload; extend the term of validity of model, and improve the modeling efficiency. The experiment of model adaptability shows that, the correct recognition rate of separate modeling method is relatively low, which can not meet the requirements of application, and joint modeling method can reach the correct recognition rate of 90%, and significantly enhances the recognition effect. The experiment of model stability shows that, the identification results of model by joint modeling are better than the model by separate modeling, and has good application value.

Development of iFab (Instant Foundry Adaptive Through Bits) Manufacturing Process and Machine Library

DTIC Science & Technology

2012-08-01

loaded joints including bearing -type shear loaded joints and friction type shear loaded joints . Appendix Figure 2f.A-3 shows an illustration of each... Loaded Joint Bearing Type Shear Loaded Joint Friction Type Shear Loaded Joint Tension Loaded Joint 62 Approved for public release...Joining of materials and structures: from pragmatic process to enabling technology.

A Comparative Study of Co-Channel Interference Suppression Techniques

NASA Technical Reports Server (NTRS)

Hamkins, Jon; Satorius, Ed; Paparisto, Gent; Polydoros, Andreas

1997-01-01

We describe three methods of combatting co-channel interference (CCI): a cross-coupled phase-locked loop (CCPLL); a phase-tracking circuit (PTC), and joint Viterbi estimation based on the maximum likelihood principle. In the case of co-channel FM-modulated voice signals, the CCPLL and PTC methods typically outperform the maximum likelihood estimators when the modulation parameters are dissimilar. However, as the modulation parameters become identical, joint Viterbi estimation provides for a more robust estimate of the co-channel signals and does not suffer as much from "signal switching" which especially plagues the CCPLL approach. Good performance for the PTC requires both dissimilar modulation parameters and a priori knowledge of the co-channel signal amplitudes. The CCPLL and joint Viterbi estimators, on the other hand, incorporate accurate amplitude estimates. In addition, application of the joint Viterbi algorithm to demodulating co-channel digital (BPSK) signals in a multipath environment is also discussed. It is shown in this case that if the interference is sufficiently small, a single trellis model is most effective in demodulating the co-channel signals.

76 FR 60006 - Joint Europe Africa Deployment & Distribution Conference 2011: “Adapting To Challenge and Change”

Federal Register 2010, 2011, 2012, 2013, 2014

2011-09-28

... DEPARTMENT OF DEFENSE Office of the Secretary Joint Europe Africa Deployment & Distribution Conference 2011: ``Adapting To Challenge and Change'' AGENCY: United States Africa Command, Department of Defense (DoD). ACTION: Notice of conference. SUMMARY: This document announces that U.S. Africa Command...

On the Role of Sensory Feedbacks in Rowat–Selverston CPG to Improve Robot Legged Locomotion

PubMed Central

Amrollah, Elmira; Henaff, Patrick

2010-01-01

This paper presents the use of Rowat and Selverston-type of central pattern generator (CPG) to control locomotion. It focuses on the role of afferent exteroceptive and proprioceptive signals in the dynamic phase synchronization in CPG legged robots. The sensori-motor neural network architecture is evaluated to control a two-joint planar robot leg that slips on a rail. Then, the closed loop between the CPG and the mechanical system allows to study the modulation of rhythmic patterns and the effect of the sensing loop via sensory neurons during the locomotion task. Firstly simulations show that the proposed architecture easily allows to modulate rhythmic patterns of the leg, and therefore the velocity of the robot. Secondly, simulations show that sensori-feedbacks from foot/ground contact of the leg make the hip velocity smoother and larger. The results show that the Rowat–Selverston-type CPG with sensory feedbacks is an effective choice for building adaptive neural CPGs for legged robots. PMID:21228904

Neuromuscular mechanisms and neural strategies in the control of time-varying muscle contractions.

PubMed

Erimaki, Sophia; Agapaki, Orsalia M; Christakos, Constantinos N

2013-09-01

The organization of the neural input to motoneurons that underlies time-varying muscle force is assumed to depend on muscle transfer characteristics and neural strategies or control modes utilizing sensory signals. We jointly addressed these interlinked, but previously studied individually and partially, issues for sinusoidal (range 0.5-5.0 Hz) force-tracking contractions of a human finger muscle. Using spectral and correlation analyses of target signal, force signal, and motor unit (MU) discharges, we studied 1) patterns of such discharges, allowing inferences on the motoneuronal input; 2) transformation of MU population activity (EMG) into quasi-sinusoidal force; and 3) relation of force oscillation to target, carrying information on the input's organization. A broad view of force control mechanisms and strategies emerged. Specifically, synchronized MU and EMG modulations, reflecting a frequency-modulated motoneuronal input, accompanied the force variations. Gain and delay drops between EMG modulation and force oscillation, critical for the appropriate organization of this input, occurred with increasing target frequency. According to our analyses, gain compensation was achieved primarily through rhythmical activation/deactivation of higher-threshold MUs and secondarily through the adaptation of the input's strength expected during tracking tasks. However, the input's timing was not adapted to delay behaviors and seemed to depend on the control modes employed. Thus, for low-frequency targets, the force oscillation was highly coherent with, but led, a target, this timing error being compatible with predictive feedforward control partly based on the target's derivatives. In contrast, the force oscillation was weakly coherent, but in phase, with high-frequency targets, suggesting control mainly based on a target's rhythm.

Fusimotor control of spindle sensitivity regulates central and peripheral coding of joint angles.

PubMed

Lan, Ning; He, Xin

2012-01-01

Proprioceptive afferents from muscle spindles encode information about peripheral joint movements for the central nervous system (CNS). The sensitivity of muscle spindle is nonlinearly dependent on the activation of gamma (γ) motoneurons in the spinal cord that receives inputs from the motor cortex. How fusimotor control of spindle sensitivity affects proprioceptive coding of joint position is not clear. Furthermore, what information is carried in the fusimotor signal from the motor cortex to the muscle spindle is largely unknown. In this study, we addressed the issue of communication between the central and peripheral sensorimotor systems using a computational approach based on the virtual arm (VA) model. In simulation experiments within the operational range of joint movements, the gamma static commands (γ(s)) to the spindles of both mono-articular and bi-articular muscles were hypothesized (1) to remain constant, (2) to be modulated with joint angles linearly, and (3) to be modulated with joint angles nonlinearly. Simulation results revealed a nonlinear landscape of Ia afferent with respect to both γ(s) activation and joint angle. Among the three hypotheses, the constant and linear strategies did not yield Ia responses that matched the experimental data, and therefore, were rejected as plausible strategies of spindle sensitivity control. However, if γ(s) commands were quadratically modulated with joint angles, a robust linear relation between Ia afferents and joint angles could be obtained in both mono-articular and bi-articular muscles. With the quadratic strategy of spindle sensitivity control, γ(s) commands may serve as the CNS outputs that inform the periphery of central coding of joint angles. The results suggest that the information of joint angles may be communicated between the CNS and muscles via the descending γ(s) efferent and Ia afferent signals.

A computerized self-compensating system for ultrasonic inspection of airplane structures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Komsky, I.N.; Achenbach, J.D.; Hagemaier, D.

1993-12-31

Application of a self-compensating technique for ultrasonic inspection of airplane structures makes it possible not only to detect cracks in the different layers of joints but also to obtain information on crack sizes. A prototype computerized ultrasonic system, which utilizes the self-compensating method, has been developed for non-destructive inspection of multilayered airplane structures with in-between sealants, such as bolted joints in tail connections. Industrial applications of the system would require deployment of commercially available portable modules for data acquisition and processing. A portable ultrasonic flaw detector EPOCH II manual scanners and HandiScan, and SQL and FCS software modules form themore » PC-based TestPro system have been selected for initial tests. A pair of contact angle-beam transducers were used to generate shear waves in the material. Both hardware and software components of the system have been modified for the application in conjunction with the self-compensating technique. The system has bene tested on two calibration specimens with artificial flaws of different sizes in internal layers of multilayered structures. Ultrasonic signals transmitted through and reflected from the artificial flaws have bene discriminated and characterized using multiple time domain amplitude gates. Then the ratios of the reflection and transmission coefficients, R/T, were calculated for several positions of the transducers. Inspection of measured R/T curves shows it is difficult to visually associate curve shapes with corresponding flaw sizes and orientation. Hence for online classification of these curve shapes, application of an adaptive signal classifier was considered. Several different types and configurations of the classifiers, including a neural network, have been tested. Test results showed that improved performance of the classifier can be achieved by combination of a back-propagation neural network with a signal pre-processing module.« less

An adaptive controller for enhancing operator performance during teleoperation

NASA Technical Reports Server (NTRS)

Carignan, Craig R.; Tarrant, Janice M.; Mosier, Gary E.

1989-01-01

An adaptive controller is developed for adjusting robot arm parameters while manipulating payloads of unknown mass and inertia. The controller is tested experimentally in a master/slave configuration where the adaptive slave arm is commanded via human operator inputs from a master. Kinematically similar six-joint master and slave arms are used with the last three joints locked for simplification. After a brief initial adaptation period for the unloaded arm, the slave arm retrieves different size payloads and maneuvers them about the workspace. Comparisons are then drawn with similar tasks where the adaptation is turned off. Several simplifications of the controller dynamics are also addressed and experimentally verified.

Lunar Module 4 moved for mating with Lunar Module Adapter at KSC

NASA Technical Reports Server (NTRS)

1969-01-01

Lunar Module 4 being moved for mating with the Spacecraft Lunar Module Adapter in the Kennedy Space Center's (KSC) Manned Spacecraft Operations Building. Lunar module 4 will be flown on the Apollo 10 (Spacecraft 106/Saturn 505) lunar orbit mission.

Spectro-temporal cues enhance modulation sensitivity in cochlear implant users

PubMed Central

Zheng, Yi; Escabí, Monty; Litovsky, Ruth Y.

2018-01-01

Although speech understanding is highly variable amongst cochlear implants (CIs) subjects, the remarkably high speech recognition performance of many CI users is unexpected and not well understood. Numerous factors, including neural health and degradation of the spectral information in the speech signal of CIs, likely contribute to speech understanding. We studied the ability to use spectro-temporal modulations, which may be critical for speech understanding and discrimination, and hypothesize that CI users adopt a different perceptual strategy than normal-hearing (NH) individuals, whereby they rely more heavily on joint spectro-temporal cues to enhance detection of auditory cues. Modulation detection sensitivity was studied in CI users and NH subjects using broadband “ripple” stimuli that were modulated spectrally, temporally, or jointly, i.e., spectro-temporally. The spectro-temporal modulation transfer functions of CI users and NH subjects was decomposed into spectral and temporal dimensions and compared to those subjects’ spectral-only and temporal-only modulation transfer functions. In CI users, the joint spectro-temporal sensitivity was better than that predicted by spectral-only and temporal-only sensitivity, indicating a heightened spectro-temporal sensitivity. Such an enhancement through the combined integration of spectral and temporal cues was not observed in NH subjects. The unique use of spectro-temporal cues by CI patients can yield benefits for use of cues that are important for speech understanding. This finding has implications for developing sound processing strategies that may rely on joint spectro-temporal modulations to improve speech comprehension of CI users, and the findings of this study may be valuable for developing clinical assessment tools to optimize CI processor performance. PMID:28601530

Photovoltaic Roofs

NASA Technical Reports Server (NTRS)

Drummond, R. W., Jr.; Shepard, N. F., Jr.

1984-01-01

Solar cells perform two functions: waterproofing roof and generating electricity. Sections through horizontal and slanting joints show overlapping modules sealed by L-section rubber strips and side-by-side modules sealed by P-section strips. Water seeping through seals of slanting joints drains along channels. Rooftop photovoltaic array used watertight south facing roof, replacing shingles, tar, and gravel. Concept reduces cost of residential solar-cell array.

Low activation steels welding with PWHT and coating for ITER test blanket modules and DEMO

NASA Astrophysics Data System (ADS)

Aubert, P.; Tavassoli, F.; Rieth, M.; Diegele, E.; Poitevin, Y.

2011-02-01

EUROFER weldability is investigated in support of the European material properties database and TBM manufacturing. Electron Beam, Hybrid, laser and narrow gap TIG processes have been carried out on the EUROFER-97 steel (thickness up to 40 mm), a reduced activation ferritic-martensitic steel developed in Europe. These welding processes produce similar welding results with high joint coefficients and are well adapted for minimizing residual distortions. The fusion zones are typically composed of martensite laths, with small grain sizes. In the heat-affected zones, martensite grains contain carbide precipitates. High hardness values are measured in all these zones that if not tempered would degrade toughness and creep resistance. PWHT developments have driven to a one-step PWHT (750 °C/3 h), successfully applied to joints restoring good material performances. It will produce less distortion levels than a full austenitization PWHT process, not really applicable to a complex welded structure such as the TBM. Different tungsten coatings have been successfully processed on EUROFER material. It has shown no really effect on the EUROFER base material microstructure.

Fast myopic 2D-SIM super resolution microscopy with joint modulation pattern estimation

NASA Astrophysics Data System (ADS)

Orieux, François; Loriette, Vincent; Olivo-Marin, Jean-Christophe; Sepulveda, Eduardo; Fragola, Alexandra

2017-12-01

Super-resolution in structured illumination microscopy (SIM) is obtained through de-aliasing of modulated raw images, in which high frequencies are measured indirectly inside the optical transfer function. Usual approaches that use 9 or 15 images are often too slow for dynamic studies. Moreover, as experimental conditions change with time, modulation parameters must be estimated within the images. This paper tackles the problem of image reconstruction for fast super resolution in SIM, where the number of available raw images is reduced to four instead of nine or fifteen. Within an optimization framework, the solution is inferred via a joint myopic criterion for image and modulation (or acquisition) parameters, leading to what is frequently called a myopic or semi-blind inversion problem. The estimate is chosen as the minimizer of the nonlinear criterion, numerically calculated by means of a block coordinate optimization algorithm. The effectiveness of the proposed method is demonstrated for simulated and experimental examples. The results show precise estimation of the modulation parameters jointly with the reconstruction of the super resolution image. The method also shows its effectiveness for thick biological samples.

Logs Analysis of Adapted Pedagogical Scenarios Generated by a Simulation Serious Game Architecture

ERIC Educational Resources Information Center

Callies, Sophie; Gravel, Mathieu; Beaudry, Eric; Basque, Josianne

2017-01-01

This paper presents an architecture designed for simulation serious games, which automatically generates game-based scenarios adapted to learner's learning progression. We present three central modules of the architecture: (1) the learner model, (2) the adaptation module and (3) the logs module. The learner model estimates the progression of the…

POEM: Identifying Joint Additive Effects on Regulatory Circuits.

PubMed

Botzman, Maya; Nachshon, Aharon; Brodt, Avital; Gat-Viks, Irit

2016-01-01

Expression Quantitative Trait Locus (eQTL) mapping tackles the problem of identifying variation in DNA sequence that have an effect on the transcriptional regulatory network. Major computational efforts are aimed at characterizing the joint effects of several eQTLs acting in concert to govern the expression of the same genes. Yet, progress toward a comprehensive prediction of such joint effects is limited. For example, existing eQTL methods commonly discover interacting loci affecting the expression levels of a module of co-regulated genes. Such "modularization" approaches, however, are focused on epistatic relations and thus have limited utility for the case of additive (non-epistatic) effects. Here we present POEM (Pairwise effect On Expression Modules), a methodology for identifying pairwise eQTL effects on gene modules. POEM is specifically designed to achieve high performance in the case of additive joint effects. We applied POEM to transcription profiles measured in bone marrow-derived dendritic cells across a population of genotyped mice. Our study reveals widespread additive, trans-acting pairwise effects on gene modules, characterizes their organizational principles, and highlights high-order interconnections between modules within the immune signaling network. These analyses elucidate the central role of additive pairwise effect in regulatory circuits, and provide computational tools for future investigations into the interplay between eQTLs. The software described in this article is available at csgi.tau.ac.il/POEM/.

POEM: Identifying Joint Additive Effects on Regulatory Circuits

PubMed Central

Botzman, Maya; Nachshon, Aharon; Brodt, Avital; Gat-Viks, Irit

2016-01-01

Motivation: Expression Quantitative Trait Locus (eQTL) mapping tackles the problem of identifying variation in DNA sequence that have an effect on the transcriptional regulatory network. Major computational efforts are aimed at characterizing the joint effects of several eQTLs acting in concert to govern the expression of the same genes. Yet, progress toward a comprehensive prediction of such joint effects is limited. For example, existing eQTL methods commonly discover interacting loci affecting the expression levels of a module of co-regulated genes. Such “modularization” approaches, however, are focused on epistatic relations and thus have limited utility for the case of additive (non-epistatic) effects. Results: Here we present POEM (Pairwise effect On Expression Modules), a methodology for identifying pairwise eQTL effects on gene modules. POEM is specifically designed to achieve high performance in the case of additive joint effects. We applied POEM to transcription profiles measured in bone marrow-derived dendritic cells across a population of genotyped mice. Our study reveals widespread additive, trans-acting pairwise effects on gene modules, characterizes their organizational principles, and highlights high-order interconnections between modules within the immune signaling network. These analyses elucidate the central role of additive pairwise effect in regulatory circuits, and provide computational tools for future investigations into the interplay between eQTLs. Availability: The software described in this article is available at csgi.tau.ac.il/POEM/. PMID:27148351

The Role of Adaptation in Body Load-Regulating Mechanisms During Locomotion

NASA Technical Reports Server (NTRS)

Ruttley, Tara; Holt, Christopher; Mulavara, Ajitkumar; Bloomberg, Jacob

2010-01-01

Body loading is a fundamental parameter that modulates motor output during locomotion, and is especially important for controlling the generation of stepping patterns, dynamic balance, and termination of locomotion. Load receptors that regulate and control posture and stance in locomotion include the Golgi tendon organs and muscle spindles at the hip, knee, and ankle joints, and the Ruffini endings and the Pacinian corpuscles in the soles of the feet. Increased body weight support (BWS) during locomotion results in an immediate reorganization of locomotor control, such as a reduction in stance and double support duration and decreased hip, ankle, and knee angles during the gait cycle. Previous studies on the effect during exposure to increased BWS while walking showed a reduction in lower limb joint angles and gait cycle timing that represents a reorganization of locomotor control. Until now, no studies have investigated how locomotor control responds after a period of exposure to adaptive modification in the body load sensing system. The goal of this research was to determine the adaptive properties of body load-regulating mechanisms in locomotor control during locomotion. We hypothesized that body load-regulating mechanisms contribute to locomotor control, and adaptive changes in these load-regulating mechanisms require reorganization to maintain forward locomotion. Head-torso coordination, lower limb movement patterns, and gait cycle timing were evaluated before and after a 30-minute adaptation session during which subjects walked on a treadmill at 5.4 km/hr with 40% body weight support (BWS). Before and after the adaptation period, head-torso and lower limb 3D kinematic data were obtained while performing a goal directed task during locomotion with 0% BWS using a video-based motion analysis system, and gait cycle timing parameters were collected by foot switches positioned under the heel and toe of the subjects shoes. Subjects showed adaptive modification in the body load-regulating mechanisms that included increased head movement amplitude, increased knee and ankle flexion, and increased stance, stride, and double support time, with no change in the performance of the task with respect to that measured before exposure to BWS. These changes in locomotor control are opposite to that reported during 40% BWS exposure and indicative of an after-effect after removal of the adaptive stimulus. Therefore, it is evident that just 30 minutes of 40% BWS during locomotion was sufficient to induce adaptive modifications in the body load sensing systems that contribute to reorganization of sensory contributions to stable locomotor control.

Comparison of neuromuscular abnormalities between upper and lower extremities in hemiparetic stroke.

PubMed

Mirbagheri, M M; AliBiglou, L; Thajchayapong, M; Lilaonitkul, T; Rymer, W Z

2006-01-01

We studied the neuromuscular mechanical properties of the elbow and ankle joints in chronic, hemiparetic stroke patients and healthy subjects. System identification techniques were used to characterize the mechanical abnormalities of these joints and to identify the contribution of intrinsic and reflex stiffness to these abnormalities. Modulation of intrinsic and reflex stiffness with the joint angle was studied by applying PRBS perturbations to the joint at different joint angles. The experiments were performed for both spastic (stroke) and contralateral (control) sides of stroke patients and one side of healthy (normal) subjects. We found reflex stiffness gain (GR) was significantly larger in the stroke than the control side for both elbow and ankle joints. GR was also strongly position dependent in both joints. However, the modulation of GR with position was slightly different in two joints. GR was also larger in the control than the normal joints but the differences were significant only for the ankle joint. Intrinsic stiffness gain (K) was also significantly larger in the stroke than the control joint at elbow extended positions and at ankle dorsiflexed positions. Modulation of K with the ankle angle was similar for stroke, control and normal groups. In contrast, the position dependency of the elbow was different. K was larger in the control than normal ankle whereas it was lower in the control than normal elbow. However, the differences were not significant for any joint. The findings demonstrate that both reflex and intrinsic stiffness gain increase abnormally in both upper and lower extremities. However, the major contribution of intrinsic and reflex stiffness to the abnormalities is at the end of ROM and at the middle ROM, respectively. The results also demonstrate that the neuromuscular properties of the contralateral limb are not normal suggesting that it may not be used as a suitable control at least for the ankle study.

Attention modulates visual size adaptation.

PubMed

Kreutzer, Sylvia; Fink, Gereon R; Weidner, Ralph

2015-01-01

The current study determined in healthy subjects (n = 16) whether size adaptation occurs at early, i.e., preattentive, levels of processing or whether higher cognitive processes such as attention can modulate the illusion. To investigate this issue, bottom-up stimulation was kept constant across conditions by using a single adaptation display containing both small and large adapter stimuli. Subjects' attention was directed to either the large or small adapter stimulus by means of a luminance detection task. When attention was directed toward the small as compared to the large adapter, the perceived size of the subsequent target was significantly increased. Data suggest that different size adaptation effects can be induced by one and the same stimulus depending on the current allocation of attention. This indicates that size adaptation is subject to attentional modulation. These findings are in line with previous research showing that transient as well as sustained attention modulates visual features, such as contrast sensitivity and spatial frequency, and influences adaptation in other contexts, such as motion adaptation (Alais & Blake, 1999; Lankheet & Verstraten, 1995). Based on a recently suggested model (Pooresmaeili, Arrighi, Biagi, & Morrone, 2013), according to which perceptual adaptation is based on local excitation and inhibition in V1, we conclude that guiding attention can boost these local processes in one or the other direction by increasing the weight of the attended adapter. In sum, perceptual adaptation, although reflected in changes of neural activity at early levels (as shown in the aforementioned study), is nevertheless subject to higher-order modulation.

Orion EM-1 Crew Module Adapter Move to Clean Room

NASA Image and Video Library

2016-11-29

Inside the Neil Armstrong Operations and Checkout Building high bay at NASA’s Kennedy Space Center in Florida, the Orion crew module adapter (CMA) for Exploration Mission 1 (EM-1) is in a clean room with protective walls secured around it. The adapter will undergo propellant and environmental control and life support system tube installation and welding. The adapter will connect the Orion crew module to the European Space Agency-provided service module. The Orion spacecraft will launch atop NASA’s Space Launch System rocket on EM-1, its first deep space mission, in late 2018.

Frequency of radiographic damage and progression in individual joints in children with juvenile idiopathic arthritis.

PubMed

Giancane, Gabriella; Pederzoli, Silvia; Norambuena, Ximena; Ioseliani, Maka; Sato, Juliana; Gallo, Maria Chiara; Negro, Giorgia; Pistorio, Angela; Ruperto, Nicolino; Martini, Alberto; Ravelli, Angelo

2014-01-01

To evaluate the presence and progression of radiographic joint damage, as assessed with the adapted Sharp/van der Heijde score (SHS), in individual joints in the hand and wrist in patients with juvenile idiopathic arthritis (JIA) and to compare progression of damage among different JIA categories. A total of 372 radiographs of both wrists and hands obtained at first observation and at last followup visit (after 1-10 years) in 186 children with polyarticular-course JIA were evaluated. All radiographs were scored using the adapted SHS by 2 independent readers. Radiographic assessment included evaluation of joint space narrowing (JSN) and erosions on baseline and last followup radiographs and of progression of radiographic changes from baseline to last followup radiographs. Both JSN and erosions occurred in all adapted SHS areas. Overall, radiographic damage and progression were more common in the wrist and less common in metacarpophalangeal (MCP) joints. The hamate and capitate areas appeared particularly vulnerable to cartilage loss. Erosions were identified most frequently in the hamate and capitate bones as well as in the second and third metacarpal bases. Patients with extended oligoarthritis were distinctly less susceptible to JSN in hand joints, whereas patients with polyarthritis showed a greater tendency to developing erosions in hand joints. Radiographic joint damage and progression in our patients with JIA were seen most commonly in the wrist and less commonly in MCP joints. The frequency and localization of structural abnormalities differed markedly across disease categories. Copyright © 2014 by the American College of Rheumatology.

Nonlinear adaptive control of an elastic robotic arm

NASA Technical Reports Server (NTRS)

Singh, S. N.

1986-01-01

An approach to control of a class of nonlinear flexible robotic systems is presented. For simplicity, a robot arm (PUMA-type) with three rotational joints is considered. The third link is assumed to be elastic. An adaptive torquer control law is derived for controlling the joint angles. This controller includes a dynamic system in the feedback path, requires only joint angle and rate for feedback, and asymptotically decomposes the elastic dynamics into two subsystems representing the transverse vibrations of the elastic link in two orthogonal planes. To damp out the elastic vibration, a force control law using modal feedback is synthesized. The combination of the torque and force control laws accomplishes joint angle control and elastic mode stabilization.

The utility of adaptive eLearning in cervical cytopathology education.

PubMed

Samulski, T Danielle; Taylor, Laura A; La, Teresa; Mehr, Chelsea R; McGrath, Cindy M; Wu, Roseann I

2018-02-01

Adaptive eLearning allows students to experience a self-paced, individualized curriculum based on prior knowledge and learning ability. The authors investigated the effectiveness of adaptive online modules in teaching cervical cytopathology. eLearning modules were created that covered basic concepts in cervical cytopathology, including artifacts and infections, squamous lesions (SL), and glandular lesions (GL). The modules used student responses to individualize the educational curriculum and provide real-time feedback. Pathology trainees and faculty from the authors' institution were randomized into 2 groups (SL or GL), and identical pre-tests and post-tests were used to compare the efficacy of eLearning modules versus traditional study methods (textbooks and slide sets). User experience was assessed with a Likert scale and free-text responses. Sixteen of 17 participants completed the SL module, and 19 of 19 completed the GL module. Participants in both groups had improved post-test scores for content in the adaptive eLearning module. Users indicated that the module was effective in presenting content and concepts (Likert scale [from 1 to 5], 4.3 of 5.0), was an efficient and convenient way to review the material (Likert scale, 4.4 of 5.0), and was more engaging than lectures and texts (Likert scale, 4.6 of 5.0). Users favored the immediate feedback and interactivity of the module. Limitations included the inability to review prior content and slow upload time for images. Learners demonstrated improvement in their knowledge after the use of adaptive eLearning modules compared with traditional methods. Overall, the modules were viewed positively by participants. Adaptive eLearning modules can provide an engaging and effective adjunct to traditional teaching methods in cervical cytopathology. Cancer Cytopathol 2018;126:129-35. © 2017 American Cancer Society. © 2017 American Cancer Society.

Expose : procedure and results of the joint experiment verification tests

NASA Astrophysics Data System (ADS)

Panitz, C.; Rettberg, P.; Horneck, G.; Rabbow, E.; Baglioni, P.

The International Space Station will carry the EXPOSE facility accommodated at the universal workplace URM-D located outside the Russian Service Module. The launch will be affected in 2005 and it is planned to stay in space for 1.5 years. The tray like structure will accomodate 2 chemical and 6 biological PI-experiments or experiment systems of the ROSE (Response of Organisms to Space Environment) consortium. EXPOSE will support long-term in situ studies of microbes in artificial meteorites, as well as of microbial communities from special ecological niches, such as endolithic and evaporitic ecosystems. The either vented or sealed experiment pockets will be covered by an optical filter system to control intensity and spectral range of solar UV irradiation. Control of sun exposure will be achieved by the use of individual shutters. To test the compatibility of the different biological systems and their adaptation to the opportunities and constraints of space conditions a profound ground support program has been developed. The procedure and first results of this joint Experiment Verification Tests (EVT) will be presented. The results will be essential for the success of the EXPOSE mission and have been done in parallel with the development and construction of the final hardware design of the facility. The results of the mission will contribute to the understanding of the organic chemistry processes in space, the biological adaptation strategies to extreme conditions, e.g. on early Earth and Mars, and the distribution of life beyond its planet of origin.

Spatial and temporal modulation of joint stiffness during multijoint movement.

PubMed

Mah, C D

2001-02-01

Joint stiffness measurements during small transient perturbations have suggested that stiffness during movement is different from that observed during posture. These observations are problematic for theories like the classical equilibrium point hypothesis, which suggest that desired trajectories during movement are enforced by joint stiffness. We measured arm impedances during large, slow perturbations to obtain detailed information about the spatial and temporal modulation of stiffness and viscosity during movement. While our measurements of stiffness magnitudes during movement generally agreed with the results of measurements using fast perturbations, they revealed that joint stiffness undergoes stereotyped changes in magnitude and aspect ratio which depend on the direction of movement and show a strong dependence on joint angles. Movement simulations using measured parameters show that the measured modulation of impedance acts as an energy conserving force field to constrain movement. This mechanism allows for a computationally simplified account of the execution of multijoint movement. While our measurements do not rule out a role for afferent feedback in force generation, the observed stereotyped restoring forces can allow a dramatic relaxation of the accuracy requirements for forces generated by other control mechanisms, such as inverse dynamical models.

Spectro-temporal cues enhance modulation sensitivity in cochlear implant users.

PubMed

Zheng, Yi; Escabí, Monty; Litovsky, Ruth Y

2017-08-01

Although speech understanding is highly variable amongst cochlear implants (CIs) subjects, the remarkably high speech recognition performance of many CI users is unexpected and not well understood. Numerous factors, including neural health and degradation of the spectral information in the speech signal of CIs, likely contribute to speech understanding. We studied the ability to use spectro-temporal modulations, which may be critical for speech understanding and discrimination, and hypothesize that CI users adopt a different perceptual strategy than normal-hearing (NH) individuals, whereby they rely more heavily on joint spectro-temporal cues to enhance detection of auditory cues. Modulation detection sensitivity was studied in CI users and NH subjects using broadband "ripple" stimuli that were modulated spectrally, temporally, or jointly, i.e., spectro-temporally. The spectro-temporal modulation transfer functions of CI users and NH subjects was decomposed into spectral and temporal dimensions and compared to those subjects' spectral-only and temporal-only modulation transfer functions. In CI users, the joint spectro-temporal sensitivity was better than that predicted by spectral-only and temporal-only sensitivity, indicating a heightened spectro-temporal sensitivity. Such an enhancement through the combined integration of spectral and temporal cues was not observed in NH subjects. The unique use of spectro-temporal cues by CI patients can yield benefits for use of cues that are important for speech understanding. This finding has implications for developing sound processing strategies that may rely on joint spectro-temporal modulations to improve speech comprehension of CI users, and the findings of this study may be valuable for developing clinical assessment tools to optimize CI processor performance. Copyright © 2017 Elsevier B.V. All rights reserved.

Game-theoretic approach to joint transmitter adaptation and power control in wireless systems.

PubMed

Popescu, Dimitrie C; Rawat, Danda B; Popescu, Otilia; Saquib, Mohamad

2010-06-01

Game theory has emerged as a new mathematical tool in the analysis and design of wireless communication systems, being particularly useful in studying the interactions among adaptive transmitters that attempt to achieve specific objectives without cooperation. In this paper, we present a game-theoretic approach to the problem of joint transmitter adaptation and power control in wireless systems, where users' transmissions are subject to quality-of-service requirements specified in terms of target signal-to-interference-plus-noise ratios (SINRs) and nonideal vector channels between transmitters and receivers are explicitly considered. Our approach is based on application of separable games, which are a specific class of noncooperative games where the players' cost is a separable function of their strategic choices. We formally state a joint codeword and power adaptation game, which is separable, and we study its properties in terms of its subgames, namely, the codeword adaptation subgame and the power adaptation subgame. We investigate the necessary conditions for an optimal Nash equilibrium and show that this corresponds to an ensemble of user codewords and powers, which maximizes the sum capacity of the corresponding multiaccess vector channel model, and for which the specified target SINRs are achieved with minimum transmitted power.

Designs of Optoelectronic Trinary Signed-Digit Multiplication by use of Joint Spatial Encodings and Optical Correlation

NASA Astrophysics Data System (ADS)

Cherri, Abdallah K.

1999-02-01

Trinary signed-digit (TSD) symbolic-substitution-based (SS-based) optical adders, which were recently proposed, are used as the basic modules for designing highly parallel optical multiplications by use of cascaded optical correlators. The proposed multiplications perform carry-free generation of the multiplication partial products of two words in constant time. Also, three different multiplication designs are presented, and new joint spatial encodings for the TSD numbers are introduced. The proposed joint spatial encodings allow one to reduce the SS computation rules involved in optical multiplication. In addition, the proposed joint spatial encodings increase the space bandwidth product of the spatial light modulators of the optical system. This increase is achieved by reduction of the numbers of pixels in the joint spatial encodings for the input TSD operands as well as reduction of the number of pixels used in the proposed matched spatial filters for the optical multipliers.

Designs of optoelectronic trinary signed-digit multiplication by use of joint spatial encodings and optical correlation.

PubMed

Cherri, A K

1999-02-10

Trinary signed-digit (TSD) symbolic-substitution-based (SS-based) optical adders, which were recently proposed, are used as the basic modules for designing highly parallel optical multiplications by use of cascaded optical correlators. The proposed multiplications perform carry-free generation of the multiplication partial products of two words in constant time. Also, three different multiplication designs are presented, and new joint spatial encodings for the TSD numbers are introduced. The proposed joint spatial encodings allow one to reduce the SS computation rules involved in optical multiplication. In addition, the proposed joint spatial encodings increase the space-bandwidth product of the spatial light modulators of the optical system. This increase is achieved by reduction of the numbers of pixels in the joint spatial encodings for the input TSD operands as well as reduction of the number of pixels used in the proposed matched spatial filters for the optical multipliers.

An evaluation of the spring finger solder joints on SA1358-10 and SA2052-4 connector assemblies (MC3617,W87).

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kilgo, Alice C.; Vianco, Paul Thomas; Hlava, Paul Frank

2006-08-01

The SA1358-10 and SA2052-4 circular JT Type plug connectors are used on a number of nuclear weapons and Joint Test Assembly (JTA) systems. Prototype units were evaluated for the following specific defects associated with the 95Sn-5Sb (Sn-Sb, wt.%) solder joint used to attach the beryllium-copper (BeCu) spring fingers to the aluminum (Al) connector shell: (1) extended cracking within the fillet; (2) remelting of the solder joint during the follow-on, soldering step that attached the EMR adapter ring to the connector shell (and/or soldering the EMR shell to the adapter ring) that used the lower melting temperature 63Sn-37Pb (Sn-Pb) alloy; andmore » (3) spalling of the Cd (Cr) layer overplating layer from the fillet surface. Several pedigrees of connectors were evaluated, which represented older fielded units as well as those assemblies that were recently constructed at Kansas City Plant. The solder joints were evaluated that were in place on connectors made with the current soldering process as well as an alternative induction soldering process for attaching the EMR adapter ring to the shell. Very similar observations were made, which crossed the different pedigrees of parts and processes. The extent of cracking in the top side fillets varied between the different connector samples and likely the EMR adapter ring to the shell. Very similar observations were made, which crossed the different pedigrees of parts and processes. The extent of cracking in the top side fillets varied between the different connector samples and likely reflected the different extents to which the connector was mated to its counterpart assembly. In all cases, the spring finger solder joints on the SA1358-10 connectors were remelted as a result of the subsequent EMR adapter ring attachment process. Spalling of the Cd (Cr) overplating layer was also observed for these connectors, which was a consequence of the remelting activity. On the other hand, the SA2052-4 connector did not exhibit evidence of remelting of the spring finger solder joint. The Cd (Cr) layer did not show signs of spalling. These results suggested that, due to the size of the SA1358-10 connector, any of the former or current soldering processes used to attach the EMR adapter ring and/or EMR shell to the connector shell, requires a level of heat energy that will always result in the remelting of the spring finger solder joint attached with either the Sn-Ag or the Sn-Sb alloy. Lastly, it was construed that the induction soldering process, which is used to attach the EMR adapter ring onto the shell, was more likely to have caused the remelting event rather than the more localized heat source of the hand soldering iron used to attach the EMR shell to the adapter ring.« less

Apollo 9 Mission image - View of the Lunar Module (LM) 3 and Service Module (SM) LM Adapter

NASA Image and Video Library

1969-03-03

View of the Lunar Module (LM) 3 and Service Module (SM) LM Adapter. Film magazine was A,film type was SO-368 Ektachrome with 0.460 - 0.710 micrometers film / filter transmittance response and haze filter, 80mm lens.

A novel joint-processing adaptive nonlinear equalizer using a modular recurrent neural network for chaotic communication systems.

PubMed

Zhao, Haiquan; Zeng, Xiangping; Zhang, Jiashu; Liu, Yangguang; Wang, Xiaomin; Li, Tianrui

2011-01-01

To eliminate nonlinear channel distortion in chaotic communication systems, a novel joint-processing adaptive nonlinear equalizer based on a pipelined recurrent neural network (JPRNN) is proposed, using a modified real-time recurrent learning (RTRL) algorithm. Furthermore, an adaptive amplitude RTRL algorithm is adopted to overcome the deteriorating effect introduced by the nesting process. Computer simulations illustrate that the proposed equalizer outperforms the pipelined recurrent neural network (PRNN) and recurrent neural network (RNN) equalizers. Copyright © 2010 Elsevier Ltd. All rights reserved.

From vision to action: roadmapping as a strategic method and tool to implement climate change adaptation - the example of the roadmap 'water sensitive urban design 2020'.

PubMed

Hasse, J U; Weingaertner, D E

2016-01-01

As the central product of the BMBF-KLIMZUG-funded Joint Network and Research Project (JNRP) 'dynaklim - Dynamic adaptation of regional planning and development processes to the effects of climate change in the Emscher-Lippe region (North Rhine Westphalia, Germany)', the Roadmap 2020 'Regional Climate Adaptation' has been developed by the various regional stakeholders and institutions containing specific regional scenarios, strategies and adaptation measures applicable throughout the region. This paper presents the method, elements and main results of this regional roadmap process by using the example of the thematic sub-roadmap 'Water Sensitive Urban Design 2020'. With a focus on the process support tool 'KlimaFLEX', one of the main adaptation measures of the WSUD 2020 roadmap, typical challenges for integrated climate change adaptation like scattered knowledge, knowledge gaps and divided responsibilities but also potential solutions and promising chances for urban development and urban water management are discussed. With the roadmap and the related tool, the relevant stakeholders of the Emscher-Lippe region have jointly developed important prerequisites to integrate their knowledge, to clarify vulnerabilities, adaptation goals, responsibilities and interests, and to foresightedly coordinate measures, resources, priorities and schedules for an efficient joint urban planning, well-grounded decision-making in times of continued uncertainties and step-by-step implementation of adaptation measures from now on.

Health Occupations Module. The Skeletal System--II.

ERIC Educational Resources Information Center

Temple Univ., Philadelphia, PA. Div. of Vocational Education.

This module on the skeletal system is one of eight modules designed for individualized instruction in health occupations education programs at both the secondary and postsecondary levels. This module contains an introduction to the module topic, two objectives (e.g., list the types of joints and movements, and give examples), and two learning…

Artificial dexterous hand

NASA Technical Reports Server (NTRS)

Lee, Sukhan (Inventor)

1990-01-01

An artificial dexterous hand is provided for conformally engaging and manipulating objects. The hand includes an articulated digit which is connected to an engagement sub-assembly and has a first shape adaption mechanism associated with it. The digit has a digit base and first and second phalanges. The digit base is operatively interconnected to the first phalange by a base joint having a base pulley. The phalanges are operatively interconnected by a separate first phalange joint having a first phalange pulley. The engagement sub-assembly includes a tendon, which is received by the base pulley and by the first phalange pulley, and an actuation device for selectively tensioning the tendon. The first shape adaption mechanism is responsive to and receives the tendon. It is also situated between the base joint and the first phalange joint and is connected to the first phalange. Upon actuation by the actuation device, the phalanges are caused to pivot relative to the base joint and the second phalange is caused to pivot relative to the first phalange. At the same time, the first shape adaption mechanism controls the sequence of the aforementioned pivoting of the phalanges through application of braking force to the tendon.

Cooperative Adaptive Output Regulation for Second-Order Nonlinear Multiagent Systems With Jointly Connected Switching Networks.

PubMed

Liu, Wei; Huang, Jie

2018-03-01

This paper studies the cooperative global robust output regulation problem for a class of heterogeneous second-order nonlinear uncertain multiagent systems with jointly connected switching networks. The main contributions consist of the following three aspects. First, we generalize the result of the adaptive distributed observer from undirected jointly connected switching networks to directed jointly connected switching networks. Second, by performing a new coordinate and input transformation, we convert our problem into the cooperative global robust stabilization problem of a more complex augmented system via the distributed internal model principle. Third, we solve the stabilization problem by a distributed state feedback control law. Our result is illustrated by the leader-following consensus problem for a group of Van der Pol oscillators.

Adapting The Joint Commission's Seven Foundations of Safe and Effective Transitions of Care to Home

PubMed Central

Labson, Margherita C.

2015-01-01

The purpose of this article is to describe The Joint Commission's 7 foundations of safe and effective transitions of care to home: (a) leadership support; (b) multidisciplinary collaboration; (c) early identification of patients/clients at risk; (d) transitional planning; (e) medication management; (f) patient and family action/engagement; and (g) transfer of information. These foundations were identified by The Joint Commission after a review of published research; focus groups with healthcare professionals involved in transitions of care; and visits to diverse healthcare organizations. The author, who is the executive director of The Joint Commission's Home Care Accreditation Program, illustrates how healthcare organizations are adapting the 7 foundations of safe and effective transitions of care to home. PMID:25742092

Thermal fatigue life evaluation of SnAgCu solder joints in a multi-chip power module

NASA Astrophysics Data System (ADS)

Barbagallo, C.; Malgioglio, G. L.; Petrone, G.; Cammarata, G.

2017-05-01

For power devices, the reliability of thermal fatigue induced by thermal cycling has been prioritized as an important concern. The main target of this work is to apply a numerical procedure to assess the fatigue life for lead-free solder joints, that represent, in general, the weakest part of the electronic modules. Starting from a real multi-chip power module, FE-based models were built-up by considering different conditions in model implementation in order to simulate, from one hand, the worst working condition for the module and, from another one, the module standing into a climatic test room performing thermal cycles. Simulations were carried-out both in steady and transient conditions in order to estimate the module thermal maps, the stress-strain distributions, the effective plastic strain distributions and finally to assess the number of cycles to failure of the constitutive solder layers.

Adaptation of multijoint coordination during standing balance in healthy young and healthy old individuals

PubMed Central

Pasma, J. H.; Schouten, A. C.; Aarts, R. G. K. M.; Meskers, C. G. M.; Maier, A. B.; van der Kooij, H.

2015-01-01

Standing balance requires multijoint coordination between the ankles and hips. We investigated how humans adapt their multijoint coordination to adjust to various conditions and whether the adaptation differed between healthy young participants and healthy elderly. Balance was disturbed by push/pull rods, applying two continuous and independent force disturbances at the level of the hip and between the shoulder blades. In addition, external force fields were applied, represented by an external stiffness at the hip, either stabilizing or destabilizing the participants' balance. Multivariate closed-loop system-identification techniques were used to describe the neuromuscular control mechanisms by quantifying the corrective joint torques as a response to body sway, represented by frequency response functions (FRFs). Model fits on the FRFs resulted in an estimation of time delays, intrinsic stiffness, reflexive stiffness, and reflexive damping of both the ankle and hip joint. The elderly generated similar corrective joint torques but had reduced body sway compared with the young participants, corresponding to the increased FRF magnitude with age. When a stabilizing or destabilizing external force field was applied at the hip, both young and elderly participants adapted their multijoint coordination by lowering or respectively increasing their neuromuscular control actions around the ankles, expressed in a change of FRF magnitude. However, the elderly adapted less compared with the young participants. Model fits on the FRFs showed that elderly had higher intrinsic and reflexive stiffness of the ankle, together with higher time delays of the hip. Furthermore, the elderly adapted their reflexive stiffness around the ankle joint less compared with young participants. These results imply that elderly were stiffer and were less able to adapt to external force fields. PMID:26719084

Adaptation of an Evidence-Based Arthritis Program for Breast Cancer Survivors on Aromatase Inhibitor Therapy Who Experience Joint Pain

PubMed Central

Callahan, Leigh F.; Rini, Christine; Altpeter, Mary; Hackney, Betsy; Schecher, Arielle; Wilson, Anne; Muss, Hyman B.

2015-01-01

Adding aromatase inhibitors (AIs) to adjuvant treatment of postmenopausal women with hormone-receptor–positive breast cancer significantly reduces cancer recurrence. A common side effect of AIs is noninflammatory joint pain and stiffness (arthralgia) similar to arthritis symptoms. An evidence-based walking program developed by the Arthritis Foundation — Walk With Ease (WWE) — reduces arthritis-related joint symptoms. We hypothesized that WWE may also reduce AI-associated arthralgia. However, the potential for different barriers and facilitators to physical activity for these 2 patient populations suggested a need to adapt WWE before testing it with breast cancer survivors. We conducted qualitative research with 46 breast cancer survivors to explore program modification and inform the development of materials for an adapted program (Walk With Ease-Breast Cancer). Our process parallels the National Cancer Institute’s Research-Tested Intervention Programs (RTIPs) guidelines for adapting evidence-based programs for cancer populations. Findings resulted in a customized 8-page brochure to supplement existing WWE materials. PMID:26068412

Effect of mandibular distraction osteogenesis on the temporomandibular joint: a systematic review of animal experimental studies.

PubMed

Andersen, Kristian; Pedersen, Thomas Klit; Hauge, Ellen Margrethe; Schou, Søren; Nørholt, Sven Erik

2014-04-01

The present systematic review aimed to test the hypothesis of no effect of mandibular distraction osteogenesis on the temporomandibular joint. Animal experimental studies from January 1985 to August 2013 were included. Studies were searched in PubMed, Embase, Scopus, and the Cochrane Library. A total of 289 articles were identified, and 17 were included. Included studies were characterized by a high risk of bias and by inhomogeneity related to animal species, experimental procedures, and evaluation methods. Mandibular distraction osteogenesis within physiologic limits may be followed by adaptive changes in bone, disk, and cartilage. Increased daily rates and total activation length may influence the severity of the adaptive changes. Animal experimental studies indicate that mandibular distraction osteogenesis may induce adaptive changes in the temporomandibular joint. Adaptive changes may be influenced by increased daily rates and total length of distraction osteogenesis. Well-designed studies are needed before final conclusions can be drawn. Copyright © 2014 Elsevier Inc. All rights reserved.

Astronaut Vance Brand at controls of Apollo Command Module

NASA Technical Reports Server (NTRS)

1975-01-01

Astronaut Vance D. Brand, command module pilot of the American ASTP crew, is seen at the controls of the Apollo Command Module during the joint U.S.-USSR Apollo Soyuz Test Project (ASTP) docking in Earth orbit mission.

Motor modules during adaptation to walking in a powered ankle exoskeleton.

PubMed

Jacobs, Daniel A; Koller, Jeffrey R; Steele, Katherine M; Ferris, Daniel P

2018-01-03

Modules of muscle recruitment can be extracted from electromyography (EMG) during motions, such as walking, running, and swimming, to identify key features of muscle coordination. These features may provide insight into gait adaptation as a result of powered assistance. The aim of this study was to investigate the changes (module size, module timing and weighting patterns) of surface EMG data during assisted and unassisted walking in an powered, myoelectric, ankle-foot orthosis (ankle exoskeleton). Eight healthy subjects wore bilateral ankle exoskeletons and walked at 1.2 m/s on a treadmill. In three training sessions, subjects walked for 40 min in two conditions: unpowered (10 min) and powered (30 min). During each session, we extracted modules of muscle recruitment via nonnegative matrix factorization (NNMF) from the surface EMG signals of ten muscles in the lower limb. We evaluated reconstruction quality for each muscle individually using R 2 and normalized root mean squared error (NRMSE). We hypothesized that the number of modules needed to reconstruct muscle data would be the same between conditions and that there would be greater similarity in module timings than weightings. Across subjects, we found that six modules were sufficient to reconstruct the muscle data for both conditions, suggesting that the number of modules was preserved. The similarity of module timings and weightings between conditions was greater then random chance, indicating that muscle coordination was also preserved. Motor adaptation during walking in the exoskeleton was dominated by changes in the module timings rather than module weightings. The segment number and the session number were significant fixed effects in a linear mixed-effect model for the increase in R 2 with time. Our results show that subjects walking in a exoskeleton preserved the number of modules and the coordination of muscles within the modules across conditions. Training (motor adaptation within the session and motor skill consolidation across sessions) led to improved consistency of the muscle patterns. Subjects adapted primarily by changing the timing of their muscle patterns rather than the weightings of muscles in the modules. The results of this study give new insight into strategies for muscle recruitment during adaptation to a powered ankle exoskeleton.

Laboratory demonstrations on a pyramid wavefront sensor without modulation for closed-loop adaptive optics system.

PubMed

Wang, Shengqian; Rao, Changhui; Xian, Hao; Zhang, Jianlin; Wang, Jianxin; Liu, Zheng

2011-04-25

The feasibility and performance of the pyramid wavefront sensor without modulation used in closed-loop adaptive optics system is investigated in this paper. The theory concepts and some simulation results are given to describe the detection trend and the linearity range of such a sensor with the aim to better understand its properties, and then a laboratory setup of the adaptive optics system based on this sensor and the liquid-crystal spatial light modulator is built. The correction results for the individual Zernike aberrations and the Kolmogorov phase screens are presented to demonstrate that the pyramid wavefront sensor without modulation can work as expected for closed-loop adaptive optics system.

Adaptive modulations of martensites.

PubMed

Kaufmann, S; Rössler, U K; Heczko, O; Wuttig, M; Buschbeck, J; Schultz, L; Fähler, S

2010-04-09

Modulated phases occur in numerous functional materials like giant ferroelectrics and magnetic shape-memory alloys. To understand the origin of these phases, we employ and generalize the concept of adaptive martensite. As a starting point, we investigate the coexistence of austenite, adaptive 14M phase, and tetragonal martensite in Ni-Mn-Ga magnetic shape-memory alloy epitaxial films. We show that the modulated martensite can be constructed from nanotwinned variants of the tetragonal martensite phase. By combining the concept of adaptive martensite with branching of twin variants, we can explain key features of modulated phases from a microscopic view. This includes metastability, the sequence of 6M-10M-14M-NM intermartensitic transitions, and the magnetocrystalline anisotropy.

ART-XC/SRG: joint calibration of mirror modules and x-ray detectors

NASA Astrophysics Data System (ADS)

Tkachenko, A.; Pavlinsky, M.; Levin, V.; Akimov, V.; Krivchenko, A.; Rotin, A.; Kuznetsova, M.; Lapshov, I.; Yaskovich, A.; Oleinikov, V.; Gubarev, M.; Ramsey, B.

2017-08-01

The Astronomical Roentgen Telescope - X-ray Concentrator (ART-XC) is a hard x-ray instrument with energy response 6-30 keV that will to be launched on board of the Spectrum Roentgen Gamma (SRG) Mission. ART-XC consists of seven co-aligned mirror modules coupled with seven focal plane CdTe double-sided strip detectors. The mirror modules had been fabricated and calibrated at the NASA Marshall Space Flight Center (MSFC). The Russian Space Research Institute (IKI) has developed and tested the X-ray detectors. The joint x-ray calibration of the mirror modules and focal plane detectors was carried out at the IKI test facility. Details of the calibration procedure and an overview of the results are presented here.

Altered paracrine signaling from the injured knee joint impairs postnatal long bone growth.

PubMed

Roselló-Díez, Alberto; Stephen, Daniel; Joyner, Alexandra L

2017-07-25

Regulation of organ growth is a poorly understood process. In the long bones, the growth plates (GPs) drive elongation by generating a scaffold progressively replaced by bone. Although studies have focused on intrinsic GP regulation, classic and recent experiments suggest that local signals also modulate GP function. We devised a genetic mouse model to study extrinsic long bone growth modulation, in which injury is specifically induced in the left hindlimb, such that the right hindlimb serves as an internal control. Remarkably, when only mesenchyme cells surrounding postnatal GPs were killed, left bone growth was nevertheless reduced. GP signaling was impaired by altered paracrine signals from the knee joint, including activation of the injury response and, in neonates, dampened IGF1 production. Importantly, only the combined prevention of both responses rescued neonatal growth. Thus, we identified signals from the knee joint that modulate bone growth and could underlie establishment of body proportions.

Hip proprioceptors preferentially modulate reflexes of the leg in human spinal cord injury

PubMed Central

Onushko, Tanya; Hyngstrom, Allison

2013-01-01

Stretch-sensitive afferent feedback from hip muscles has been shown to trigger long-lasting, multijoint reflex responses in people with chronic spinal cord injury (SCI). These reflexes could have important implications for control of leg movements during functional activities, such as walking. Because the control of leg movement relies on reflex regulation at all joints of the limb, we sought to determine whether stretch of hip muscles modulates reflex activity at the knee and ankle and, conversely, whether knee and ankle stretch afferents affect hip-triggered reflexes. A custom-built servomotor apparatus was used to stretch the hip muscles in nine chronic SCI subjects by oscillating the legs about the hip joint bilaterally from 10° of extension to 40° flexion. To test whether stretch-related feedback from the knee or ankle would be affected by hip movement, patellar tendon percussions and Achilles tendon vibration were delivered when the hip was either extending or flexing. Surface electromyograms (EMGs) and joint torques were recorded from both legs. Patellar tendon percussions and Achilles tendon vibration both elicited reflex responses local to the knee or ankle, respectively, and did not influence reflex responses observed at the hip. Rather, the movement direction of the hip modulated the reflex responses local to the joint. The patellar tendon reflex amplitude was larger when the perturbation was delivered during hip extension compared with hip flexion. The response to Achilles vibration was modulated by hip movement, with an increased tonic component during hip flexion compared with extension. These results demonstrate that hip-mediated sensory signals modulate activity in distal muscles of the leg and appear to play a unique role in modulation of spastic muscle activity throughout the leg in SCI. PMID:23615544

Effects of Joint Attention on Long-Term Memory in 9-Month-Old Infants: An Event-Related Potentials Study

ERIC Educational Resources Information Center

Kopp, Franziska; Lindenberger, Ulman

2011-01-01

Joint attention develops during the first year of life but little is known about its effects on long-term memory. We investigated whether joint attention modulates long-term memory in 9-month-old infants. Infants were familiarized with visually presented objects in either of two conditions that differed in the degree of joint attention (high…

Orion EM-1 Crew Module Adapter Move to Clean Room

NASA Image and Video Library

2016-11-29

Inside the Neil Armstrong Operations and Checkout Building high bay at NASA’s Kennedy Space Center in Florida, the Orion crew module adapter (CMA) for Exploration Mission 1 (EM-1) is being moved to a clean room. The CMA will undergo propellant and environmental control and life support system tube installation and welding. The adapter will connect the Orion crew module to the European Space Agency-provided service module. The Orion spacecraft will launch atop NASA’s Space Launch System rocket on EM-1, its first deep space mission, in late 2018.

Orion EM-1 Crew Module Adapter Move to Clean Room

NASA Image and Video Library

2016-11-29

Inside the Neil Armstrong Operations and Checkout Building high bay at NASA’s Kennedy Space Center in Florida, Lockheed Martin technicians move the Orion crew module adapter (CMA) for Exploration Mission 1 (EM-1) into a clean room. The CMA will undergo propellant and environmental control and life support system tube installation and welding. The adapter will connect the Orion crew module to the European Space Agency-provided service module. The Orion spacecraft will launch atop NASA’s Space Launch System rocket on EM-1, its first deep space mission, in late 2018.

Orion EM-1 Crew Module Adapter Move to Clean Room

NASA Image and Video Library

2016-11-29

Inside the Neil Armstrong Operations and Checkout Building high bay at NASA’s Kennedy Space Center in Florida, Lockheed Martin technicians move the Orion crew module adapter (CMA) for Exploration Mission 1 (EM-1) toward a clean room. The CMA will undergo propellant and environmental control and life support system tube installation and welding. The adapter will connect the Orion crew module to the European Space Agency-provided service module. The Orion spacecraft will launch atop NASA’s Space Launch System rocket on EM-1, its first deep space mission, in late 2018.

Bone Repair and Military Readiness

DTIC Science & Technology

2012-10-25

formation. Orthopedic surgeons have had to adapt surgical techniques to account for issues with cementing total joint prostheses and subsequent total joint ...the silorane composite has the potential to support osseous integration around the cemented total joint implant and may generate less immunogenic wear...factors, and potential for osseointegration/osseoinduction, this material has potential to be used for screw augmentation, total hip/knee joint

Adapting the Training Site to Training Needs. Self-Paced Instructional Module. Module Number VII-A.

ERIC Educational Resources Information Center

King, Sylvester; Brooks, Kent

One of 33 self-paced instructional modules for training industry services leaders to provide guidance in the performance of manpower services by public agencies to new and expanding private industry, this module contains three sequential learning activities on adapting the training site to training needs. The first learning activity is designed to…

Packaging of ferroelectric liquid crystal-on-silicon spatial light modulators

NASA Astrophysics Data System (ADS)

Lin, W.; Morozova, Nina D.; Ju, TehHua; Zhang, Weidong; Lee, Yung-Cheng; McKnight, Douglas J.; Johnson, Kristina M.

1996-11-01

A self-pulling soldering technology has been demonstrated for assembling liquid crystal on silicon (LCOS) spatial light modulators (SLMs). One of the major challenges in manufacturing the LCOS modules is to reproducibly control the thickness of the gap between the very large scale integrated circuit (VLSI) chip and the cover glass. The liquid crystal material is sandwiched between the VLSI chop and the cover glass which is coated with a transparent conductor. Solder joints with different profiles and sizes have been designed to provide surface tension forces to control the gap accommodating the ferroelectric liquid crystal layer in the range of a micron level with sub- micron uniformity. The optimum solder joint design is defined as a joint that results in the maximum pulling force. This technology provides an automatic, batch assembly process for a LCOS SLM through one reflow process. Fluxless soldering technology is used to assemble the module. This approach avoids residues from chemical of flux and oxides, and eliminates potential contamination to the device. Two different LCOS SLM designs and the process optimization are described.

An adaptive inverse kinematics algorithm for robot manipulators

NASA Technical Reports Server (NTRS)

Colbaugh, R.; Glass, K.; Seraji, H.

1990-01-01

An adaptive algorithm for solving the inverse kinematics problem for robot manipulators is presented. The algorithm is derived using model reference adaptive control (MRAC) theory and is computationally efficient for online applications. The scheme requires no a priori knowledge of the kinematics of the robot if Cartesian end-effector sensing is available, and it requires knowledge of only the forward kinematics if joint position sensing is used. Computer simulation results are given for the redundant seven-DOF robotics research arm, demonstrating that the proposed algorithm yields accurate joint angle trajectories for a given end-effector position/orientation trajectory.

Cognitive and adaptive correlates of an ADOS-derived joint attention composite

PubMed Central

Harrison, Ashley Johnson; Lu, Zhenqiu (Laura); McLean, Rebecca L.; Sheinkopf, Stephen J.

2016-01-01

Joint attention skills have been shown to predict language outcomes in children with autism spectrum disorder (ASD). Less is known about the relationship between joint attention (JA) abilities in children with ASD and cognitive and adaptive abilities. In the current study, a subset of items from the Autism Diagnostic Observation Schedule (ADOS), designed to quantify JA abilities, were used to investigate social attention among an unusually large cross-sectional sample of children with ASD (n = 1061). An examination of the association between JA and a range of functional correlates (cognitive and adaptive) revealed JA was significantly related to verbal (VIQ) and non-verbal (NVIQ) cognitive ability as well as all domains of adaptive functioning (socialization, communication, and daily living skills). Additional analyses examined the degree to which the relation between adaptive abilities (socialization, communication, and daily living skills) and JA was maintained after taking into account the potentially mediating role of verbal and nonverbal cognitive ability. Results revealed that VIQ fully mediated the relation between JA and adaptive functioning, whereas the relation between these adaptive variables and JA was only partially mediated by NVIQ. Moderation analyses were also conducted to examine how verbal and non-verbal cognitive ability and gender impacted the relation between JA and adaptive functioning. In line with research showing a relation between language and JA, this indicates that while JA is significantly related to functional outcomes, this appears to be mediated specifically through a verbal cognitive pathway. PMID:28168003

How Well Can Modern Nonhabitual Barefoot Youth Adapt to Barefoot and Minimalist Barefoot Technology Shoe Walking, in regard to Gait Symmetry.

PubMed

Xu, Y; Hou, Q; Wang, C; Simpson, T; Bennett, B; Russell, S

2017-01-01

We aim to test how well modern nonhabitual barefoot people can adapt to barefoot and Minimalist Bare Foot Technology (MBFT) shoes, in regard to gait symmetry. 28 healthy university students (22 females/6 males) were recruited to walk on a 10-meter walkway randomly on barefoot, in MBFT shoes, and in neutral running shoes at their comfortable walking speed. Kinetic and kinematic data were collected using an 8-camera motion capture system. Data of joint angles, joint forces, and joint moments were extracted to compute a consecutive symmetry index. Compared to walking in neutral running shoes, walking barefoot led to worse symmetry of the following: ankle joint force in sagittal plane, knee joint moment in transverse plane, and ankle joint moment in frontal plane, while improving the symmetry of joint angle in sagittal plane at ankle joints and global (hip-knee-ankle) level. Walking in MBFT shoes had intermediate gait symmetry performance as compared to walking barefoot/walking in neutral running shoes. We conclude that modern nonhabitual barefoot adults will lose some gait symmetry in joint force/moment if they switch to barefoot walking without fitting in; MBFT shoe might be an ideal compromise for healthy youth as regards gait symmetry in walking.

Adaptive Shape Functions and Internal Mesh Adaptation for Modelling Progressive Failure in Adhesively Bonded Joints

NASA Technical Reports Server (NTRS)

Stapleton, Scott; Gries, Thomas; Waas, Anthony M.; Pineda, Evan J.

2014-01-01

Enhanced finite elements are elements with an embedded analytical solution that can capture detailed local fields, enabling more efficient, mesh independent finite element analysis. The shape functions are determined based on the analytical model rather than prescribed. This method was applied to adhesively bonded joints to model joint behavior with one element through the thickness. This study demonstrates two methods of maintaining the fidelity of such elements during adhesive non-linearity and cracking without increasing the mesh needed for an accurate solution. The first method uses adaptive shape functions, where the shape functions are recalculated at each load step based on the softening of the adhesive. The second method is internal mesh adaption, where cracking of the adhesive within an element is captured by further discretizing the element internally to represent the partially cracked geometry. By keeping mesh adaptations within an element, a finer mesh can be used during the analysis without affecting the global finite element model mesh. Examples are shown which highlight when each method is most effective in reducing the number of elements needed to capture adhesive nonlinearity and cracking. These methods are validated against analogous finite element models utilizing cohesive zone elements.

Optical Fiber Sensors For Monitoring Joint Articulation And Chest Expansion Of A Human Body

DOEpatents

Muhs, Jeffrey D.; Allison, Stephen W.

1997-12-23

Fiber-optic sensors employing optical fibers of elastomeric material are incorporated in devices adapted to be worn by human beings in joint and chest regions for the purpose of monitoring and measuring the extent of joint articulation and chest expansion especially with respect to time.

Research on adaptive optics image restoration algorithm based on improved joint maximum a posteriori method

NASA Astrophysics Data System (ADS)

Zhang, Lijuan; Li, Yang; Wang, Junnan; Liu, Ying

2018-03-01

In this paper, we propose a point spread function (PSF) reconstruction method and joint maximum a posteriori (JMAP) estimation method for the adaptive optics image restoration. Using the JMAP method as the basic principle, we establish the joint log likelihood function of multi-frame adaptive optics (AO) images based on the image Gaussian noise models. To begin with, combining the observed conditions and AO system characteristics, a predicted PSF model for the wavefront phase effect is developed; then, we build up iterative solution formulas of the AO image based on our proposed algorithm, addressing the implementation process of multi-frame AO images joint deconvolution method. We conduct a series of experiments on simulated and real degraded AO images to evaluate our proposed algorithm. Compared with the Wiener iterative blind deconvolution (Wiener-IBD) algorithm and Richardson-Lucy IBD algorithm, our algorithm has better restoration effects including higher peak signal-to-noise ratio ( PSNR) and Laplacian sum ( LS) value than the others. The research results have a certain application values for actual AO image restoration.

Neuromuscular properties of different spastic human joints vary systematically.

PubMed

Mirbagheri, M M; Settle, K

2010-01-01

We quantified the mechanical abnormalities of the spastic wrist in chronic stroke survivors, and determined whether these findings were representative of those recorded at the elbow and ankle joints. System identification techniques were used to characterize the mechanical abnormalities of these joints and to identify the contribution of intrinsic and reflex stiffness to these abnormalities. Modulation of intrinsic and reflex stiffness with the joint angle was studied by applying PRBS perturbations to the joints at different joint angles over the range of motion. Age-matched healthy subjects were used as control.

Erectable/deployable concepts for large space system technology

NASA Technical Reports Server (NTRS)

Agan, W. E.

1980-01-01

Erectable/deployable space structure concepts particularly relating to the development of a science and applications space platform are presented. Design and operating features for an automatic coupler clevis joint, a side latching detent joint, and a module-to-module auto lock coupler are given. An analysis of the packaging characteristics of stacked subassembly, single fold, hybrid, and double fold concepts is given for various platform structure configurations. Payload carrier systems and assembly techniques are also discussed.

Modulation of joint moments and work in the goat hindlimb with locomotor speed and surface grade

PubMed Central

Arnold, Allison S.; Lee, David V.; Biewener, Andrew A.

2013-01-01

SUMMARY Goats and other quadrupeds must modulate the work output of their muscles to accommodate the changing mechanical demands associated with locomotion in their natural environments. This study examined which hindlimb joint moments goats use to generate and absorb mechanical energy on level and sloped surfaces over a range of locomotor speeds. Ground reaction forces and the three-dimensional locations of joint markers were recorded as goats walked, trotted and galloped over 0, +15 and −15 deg sloped surfaces. Net joint moments, powers and work were estimated at the goats' hip, knee, ankle and metatarsophalangeal joints throughout the stance phase via inverse dynamics calculations. Differences in locomotor speed on the level, inclined and declined surfaces were characterized and accounted for by fitting regression equations to the joint moment, power and work data plotted versus non-dimensionalized speed. During level locomotion, the net work generated by moments at each of the hindlimb joints was small (less than 0.1 J kg−1 body mass) and did not vary substantially with gait or locomotor speed. During uphill running, by contrast, mechanical energy was generated at the hip, knee and ankle, and the net work at each of these joints increased dramatically with speed (P<0.05). The greatest increases in positive joint work occurred at the hip and ankle. During downhill running, mechanical energy was decreased in two main ways: goats generated larger knee extension moments in the first half of stance, absorbing energy as the knee flexed, and goats generated smaller ankle extension moments in the second half of stance, delivering less energy. The goats' hip extension moment in mid-stance was also diminished, contributing to the decrease in energy. These analyses offer new insight into quadrupedal locomotion, clarifying how the moments generated by hindlimb muscles modulate mechanical energy at different locomotor speeds and grades, as needed to accommodate the demands of variable terrain. PMID:23470662

Decentralized Adaptive Control For Robots

NASA Technical Reports Server (NTRS)

Seraji, Homayoun

1989-01-01

Precise knowledge of dynamics not required. Proposed scheme for control of multijointed robotic manipulator calls for independent control subsystem for each joint, consisting of proportional/integral/derivative feedback controller and position/velocity/acceleration feedforward controller, both with adjustable gains. Independent joint controller compensates for unpredictable effects, gravitation, and dynamic coupling between motions of joints, while forcing joints to track reference trajectories. Scheme amenable to parallel processing in distributed computing system wherein each joint controlled by relatively simple algorithm on dedicated microprocessor.

Development of a Thermoelectric Module Suitable for Vehicles and Based on CoSb3 Manufactured Close to Production

NASA Astrophysics Data System (ADS)

Klein Altstedde, Mirko; Sottong, Reinhard; Freitag, Oliver; Kober, Martin; Dreißigacker, Volker; Zabrocki, Knud; Szabo, Patric

2015-06-01

Despite the ongoing electrification of vehicle propulsion systems, vehicles with combustion engines will continue to bear the brunt of passenger services worldwide for the next few decades. As a result, the German Aerospace Center Institute of Vehicle Concepts, the Institute of Materials Research and the Institute of Technical Thermodynamics have focused on utilising the exhaust heat of internal combustion engines by means of thermoelectric generators (TEGs). Their primary goal is the development of cost-efficient TEGs with long-term stability and maximised energy yield. In addition to the overall TEG system design, the development of long-term stable, efficient thermoelectric modules (TEMs) for high-temperature applications is a great challenge. This paper presents the results of internal development work and reveals an expedient module design for use in TEGs suitable for vehicles. The TEM requirements identified, which were obtained by means of experiments on the test vehicle and test bench, are described first. Doped semiconductor materials were produced and characterised by production methods capable of being scaled up in order to represent series application. The results in terms of thermoelectric properties (Seebeck coefficient, electrical conductivity and thermal conductivity) were used for the simulative design of a thermoelectric module using a constant-property model and with the aid of FEM calculations. Thermomechanical calculations of material stability were carried out in addition to the TEM's thermodynamic and thermoelectric design. The film sequence within the module represented a special challenge. Multilayer films facilitated adaptation of the thermal and mechanical properties of plasma-sprayed films. A joint which dispenses with solder additives was also possible using multilayer films. The research resulted in a functionally-optimised module design, which was enhanced for use in motor vehicles using process flexibility and close-to-production manufacturing methods.

Biomechanical Effects of Stiffness in Parallel With the Knee Joint During Walking.

PubMed

Shamaei, Kamran; Cenciarini, Massimo; Adams, Albert A; Gregorczyk, Karen N; Schiffman, Jeffrey M; Dollar, Aaron M

2015-10-01

The human knee behaves similarly to a linear torsional spring during the stance phase of walking with a stiffness referred to as the knee quasi-stiffness. The spring-like behavior of the knee joint led us to hypothesize that we might partially replace the knee joint contribution during stance by utilizing an external spring acting in parallel with the knee joint. We investigated the validity of this hypothesis using a pair of experimental robotic knee exoskeletons that provided an external stiffness in parallel with the knee joints in the stance phase. We conducted a series of experiments involving walking with the exoskeletons with four levels of stiffness, including 0%, 33%, 66%, and 100% of the estimated human knee quasi-stiffness, and a pair of joint-less replicas. The results indicated that the ankle and hip joints tend to retain relatively invariant moment and angle patterns under the effects of the exoskeleton mass, articulation, and stiffness. The results also showed that the knee joint responds in a way such that the moment and quasi-stiffness of the knee complex (knee joint and exoskeleton) remains mostly invariant. A careful analysis of the knee moment profile indicated that the knee moment could fully adapt to the assistive moment; whereas, the knee quasi-stiffness fully adapts to values of the assistive stiffness only up to ∼80%. Above this value, we found biarticular consequences emerge at the hip joint.

Lunar Module 5 ascent stage being moved for mating with adapter

NASA Technical Reports Server (NTRS)

1969-01-01

Interior view of the Kennedy Space Center's (KSC) Manned Spacecraft Operations Building showing Lunar Module 5 being moved from workstand for mating with its Spacecraft Lunar Module Adapter (SLA). LM-5 is scheduled to be flown on the Apollo 11 lunar landing mission.

Orion EM-1 Crew Module Adapter Move to Clean Room

NASA Image and Video Library

2016-11-29

Inside the Neil Armstrong Operations and Checkout Building high bay at NASA’s Kennedy Space Center in Florida, Lockheed Martin technicians begin to move the Orion crew module adapter (CMA) for Exploration Mission 1 (EM-1) to a clean room. The CMA will undergo propellant and environmental control and life support system tube installation and welding. The adapter will connect the Orion crew module to the European Space Agency-provided service module. The Orion spacecraft will launch atop NASA’s Space Launch System rocket on EM-1, its first deep space mission, in late 2018.

Orion EM-1 Crew Module Adapter Move to Clean Room

NASA Image and Video Library

2016-11-29

Inside the Neil Armstrong Operations and Checkout Building high bay at NASA's Kennedy Space Center in Florida, Lockheed Martin technicians secure a protective cover around the Orion crew module adapter (CMA) for Exploration Mission 1 (EM-1) for its move to a clean room. The CMA will undergo propellant and environmental control and life support system tube installation and welding. The adapter will connect the Orion crew module to the European Space Agency-provided service module. The Orion spacecraft will launch atop NASA’s Space Launch System rocket on EM-1, its first deep space mission, in late 2018.

Orion EM-1 Crew Module Adapter Move to Clean Room

NASA Image and Video Library

2016-11-29

Inside the Neil Armstrong Operations and Checkout Building high bay at NASA’s Kennedy Space Center in Florida, a Lockheed Martin technician secures a protective cover around the Orion crew module adapter (CMA) for Exploration Mission 1 (EM-1) for its move to a clean room The CMA will undergo propellant and environmental control and life support system tube installation and welding. The adapter will connect the Orion crew module to the European Space Agency-provided service module. The Orion spacecraft will launch atop NASA’s Space Launch System rocket on EM-1, its first deep space mission, in late 2018.

Orion EM-1 Crew Module Adapter Move to Clean Room

NASA Image and Video Library

2016-11-29

Inside the Neil Armstrong Operations and Checkout Building high bay at NASA’s Kennedy Space Center in Florida, Lockheed Martin technicians secure a protective cover around the Orion crew module adapter (CMA) for Exploration Mission 1 (EM-1) for its move to a clean room. The CMA will undergo propellant and environmental control and life support system tube installation and welding. The adapter will connect the Orion crew module to the European Space Agency-provided service module. The Orion spacecraft will launch atop NASA’s Space Launch System rocket on EM-1, its first deep space mission, in late 2018.

Orion EM-1 Crew Module Adapter Move to Clean Room

NASA Image and Video Library

2016-11-29

Inside the Neil Armstrong Operations and Checkout Building high bay at NASA’s Kennedy Space Center in Florida, a protective cover is installed around the Orion crew module adapter (CMA) for Exploration Mission 1 (EM-1) for its move to a clean room. The CMA will undergo propellant and environmental control and life support system tube installation and welding. The adapter will connect the Orion crew module to the European Space Agency-provided service module. The Orion spacecraft will launch atop NASA’s Space Launch System rocket on EM-1, its first deep space mission, in late 2018.

Orion EM-1 Crew Module Adapter Move to Clean Room

NASA Image and Video Library

2016-11-29

Inside the Neil Armstrong Operations and Checkout Building high bay at NASA’s Kennedy Space Center in Florida, Lockheed Martin technicians are preparing the Orion crew module adapter (CMA) for Exploration Mission 1 (EM-1) for the move into a clean room. The CMA will undergo propellant and environmental control and life support system tube installation and welding. The adapter will connect the Orion crew module to the European Space Agency-provided service module. The Orion spacecraft will launch atop NASA’s Space Launch System rocket on EM-1, its first deep space mission, in late 2018.

Orion EM-1 Crew Module Adapter Move to Clean Room

NASA Image and Video Library

2016-11-29

Inside the Neil Armstrong Operations and Checkout Building high bay at NASA's Kennedy Space Center in Florida, Lockheed Martin technicians secure a protective cover around the Orion crew module adapter (CMA) for Exploration Mission 1 (EM-1) for its move to a clean. The CMA will undergo propellant and environmental control and life support system tube installation and welding. The adapter will connect the Orion crew module to the European Space Agency-provided service module. The Orion spacecraft will launch atop NASA’s Space Launch System rocket on EM-1, its first deep space mission, in late 2018.

Longitudinal effects of adaptive interventions with a speech-generating devicein minimally verbal children with ASD

PubMed Central

Almirall, Daniel; DiStefano, Charlotte; Chang, Ya-Chih; Shire, Stephanie; Kaiser, Ann; Lu, Xi; Nahum-Shani, Inbal; Landa, Rebecca; Mathy, Pamela; Kasari, Connie

2016-01-01

Objective There are limited data on the effects of adaptive social communication interventions with a speech-generating device in autism. This study is the first to compare growth in communications outcomes among three adaptive interventions in school-aged children with autism spectrum disorder (ASD) who are minimally verbal. Methods Sixty-one children, aged 5–8 years participated in a sequential, multiple-assignment randomized trial (SMART). All children received a developmental communication intervention: joint attention, symbolic play, engagement and regulation (JASP) with enhanced milieu teaching (EMT). The SMART included three two-stage, 24-week adaptive interventions with different provisions of a speech-generating device (SGD) in the context of JASP+EMT. The first adaptive intervention, with no SGD, initially assigned JASP+EMT alone; then intensified JASP+EMT for slow responders. In the second adaptive intervention, slow responders to JASP+EMT were assigned JASP+EMT+SGD. The third adaptive intervention initially assigned JASP+EMT+SGD; then intensified JASP+EMT+SGD for slow responders. Analyses examined between-group differences in change in outcomes from baseline to week 36. Verbal outcomes included spontaneous communicative utterances and novel words. Non-linguistic communication outcomes included initiating joint attention and behavior regulation, and play. Results The adaptive intervention beginning with JASP+EMT+SGD was estimated as superior. There were significant (P<0.05) between-group differences in change in spontaneous communicative utterances and initiating joint attention. Conclusions School-aged children with ASD who are minimally verbal make significant gains in communication outcomes with an adaptive intervention beginning with JASP+EMT+SGD. Future research should explore mediators and moderators of the adaptive intervention effects and second-stage intervention options that further capitalize on early gains in treatment. PMID:26954267

Sulforaphane Modulates Joint Inflammation in a Murine Model of Complete Freund's Adjuvant-Induced Mono-Arthritis.

PubMed

Silva Rodrigues, João Francisco; Silva E Silva, Cristiane; França Muniz, Thayanne; de Aquino, Alana Fernanda; Neuza da Silva Nina, Larissa; Fialho Sousa, Nagila Caroline; Nascimento da Silva, Luis Claudio; de Souza, Breno Glaessner Gomes Fernandes; da Penha, Tatiana Aranha; Abreu-Silva, Ana Lúcia; de Sá, Joicy Cortez; Soares Fernandes, Elizabeth; Grisotto, Marcos Augusto Grigolin

2018-04-24

Rheumatoid arthritis (RA) is characterized by inflammation of one or more joints, and affects ~1% of the adult population worldwide. Sulforaphane (SFN) is a natural compound that has been suggested as an antioxidant. Here, SFN’s effects were evaluated in a murine mono-arthritis model. Mono-arthritis was induced in mice by a single intra-articular injection of Complete Freund’s Adjuvant (CFA-10 µg/joint, in 10 µL) into the ipsilateral joint. The contralateral joint received an equal volume of PBS. On the 4th day post-joint inflammation induction, animals received either SFN (10 mg/kg) or vehicle (3% DMSO in saline), intraperitoneally (i.p.), twice a day for 3 days. Joint swelling and secondary mechanical allodynia and hyperalgesia were evaluated over 7 days post-CFA. After this period, animals were culled and their blood and synovial fluid samples were collected for analysis of cell populations, cytokine release and thioredoxin reductase (TrxR) activity. Knee joint samples were also collected for histology. SFN reduced joint swelling and damage whilst increasing the recruitment of Ly6C⁺ and Ly6G⁺ cells to CFA-injected joints. SFN-treated animals presented down-regulation of CD11b and CD62L on synovial fluid Ly6G⁺ cells. Synovial fluid samples obtained from CFA-injected joints and plasma samples of SFN-treated mice presented higher levels of IL-6 and increased activity of TrxR, in comparison with controls. These results indicate that SFN reduces knee joint damage by modulating cell activation/migration to the joints, cytokine production and increasing the activity of TrxR, and therefore, may represent an alternative treatment to joint inflammation.

Manycast routing, modulation level and spectrum assignment over elastic optical networks

NASA Astrophysics Data System (ADS)

Luo, Xiao; Zhao, Yang; Chen, Xue; Wang, Lei; Zhang, Min; Zhang, Jie; Ji, Yuefeng; Wang, Huitao; Wang, Taili

2017-07-01

Manycast is a point to multi-point transmission framework that requires a subset of destination nodes successfully reached. It is particularly applicable for dealing with large amounts of data simultaneously in bandwidth-hungry, dynamic and cloud-based applications. As rapid increasing of traffics in these applications, the elastic optical networks (EONs) may be relied on to achieve high throughput manycast. In terms of finer spectrum granularity, the EONs could reach flexible accessing to network spectrum and efficient providing exact spectrum resource to demands. In this paper, we focus on the manycast routing, modulation level and spectrum assignment (MA-RMLSA) problem in EONs. Both EONs planning with static manycast traffic and EONs provisioning with dynamic manycast traffic are investigated. An integer linear programming (ILP) model is formulated to derive MA-RMLSA problem in static manycast scenario. Then corresponding heuristic algorithm called manycast routing, modulation level and spectrum assignment genetic algorithm (MA-RMLSA-GA) is proposed to adapt for both static and dynamic manycast scenarios. The MA-RMLSA-GA optimizes MA-RMLSA problem in destination nodes selection, routing light-tree constitution, modulation level allocation and spectrum resource assignment jointly, to achieve an effective improvement in network performance. Simulation results reveal that MA-RMLSA strategies offered by MA-RMLSA-GA have slightly disparity from the optimal solutions provided by ILP model in static scenario. Moreover, the results demonstrate that MA-RMLSA-GA realizes a highly efficient MA-RMLSA strategy with the lowest blocking probability in dynamic scenario compared with benchmark algorithms.

Adaptive Physical Education: Instructional Module for Special Education Minors.

ERIC Educational Resources Information Center

Smyser, Sheryl; And Others

This module is designed to familiarize students preparing to be special education teachers with the physical needs of the exceptional student. Information is given on how to structure an adaptive physical education program designed to meet those needs, including development of an individualized education program (IEP). The module covers such…

A New Technique for Compensating Joint Limits in a Robot Manipulator

NASA Technical Reports Server (NTRS)

Litt, Jonathan; Hickman, Andre; Guo, Ten-Huei

1996-01-01

A new robust, optimal, adaptive technique for compensating rate and position limits in the joints of a six degree-of-freedom elbow manipulator is presented. In this new algorithm, the unmet demand as a result of actuator saturation is redistributed among the remaining unsaturated joints. The scheme is used to compensate for inadequate path planning, problems such as joint limiting, joint freezing, or even obstacle avoidance, where a desired position and orientation are not attainable due to an unrealizable joint command. Once a joint encounters a limit, supplemental commands are sent to other joints to best track, according to a selected criterion, the desired trajectory.

Changes in auditory nerve responses across the duration of sinusoidally amplitude-modulated electric pulse-train stimuli.

PubMed

Hu, Ning; Miller, Charles A; Abbas, Paul J; Robinson, Barbara K; Woo, Jihwan

2010-12-01

Response rates of auditory nerve fibers (ANFs) to electric pulse trains change over time, reflecting substantial spike-rate adaptation that depends on stimulus parameters. We hypothesize that adaptation affects the representation of amplitude-modulated pulse trains used by cochlear prostheses to transmit speech information to the auditory system. We recorded cat ANF responses to sinusoidally amplitude-modulated (SAM) trains with 5,000 pulse/s carriers. Stimuli delivered by a monopolar intracochlear electrode had fixed modulation frequency (100 Hz) and depth (10%). ANF responses were assessed by spike-rate measures, while representation of modulation was evaluated by vector strength (VS) and the fundamental component of the fast Fourier transform (F(0) amplitude). These measures were assessed across the 400 ms duration of pulse-train stimuli, a duration relevant to speech stimuli. Different stimulus levels were explored and responses were categorized into four spike-rate groups to assess level effects across ANFs. The temporal pattern of rate adaptation to modulated trains was similar to that of unmodulated trains, but with less rate adaptation. VS to the modulator increased over time and tended to saturate at lower spike rates, while F(0) amplitude typically decreased over time for low driven rates and increased for higher driven rates. VS at moderate and high spike rates and degree of F(0) amplitude temporal changes at low and moderate spike rates were positively correlated with the degree of rate adaptation. Thus, high-rate carriers will modify the ANF representation of the modulator over time. As the VS and F(0) measures were sensitive to adaptation-related changes over different spike-rate ranges, there is value in assessing both measures.

Designs and performance of three new microprocessor-controlled knee joints.

PubMed

Thiele, Julius; Schöllig, Christina; Bellmann, Malte; Kraft, Marc

2018-02-09

A crossover design study with a small group of subjects was used to evaluate the performance of three microprocessor-controlled exoprosthetic knee joints (MPKs): C-Leg 4, Plié 3 and Rheo Knee 3. Given that the mechanical designs and control algorithms of the joints determine the user outcome, the influence of these inherent differences on the functional characteristics was investigated in this study. The knee joints were evaluated during level-ground walking at different velocities in a motion analysis laboratory. Additionally, technical analyses using patents, technical documentations and X-ray computed tomography (CT) for each knee joint were performed. The technical analyses showed that only C-Leg 4 and Rheo Knee 3 allow microprocessor-controlled adaptation of the joint resistances for different gait velocities. Furthermore, Plié 3 is not able to provide stance extension damping. The biomechanical results showed that only if a knee joint adapts flexion and extension resistances by the microprocessor all known advantages of MPKs can become apparent. But not all users may benefit from the examined functions: e.g. a good accommodation to fast walking speeds or comfortable stance phase flexion. Hence, a detailed comparison of user demands and performance of the designated knee joint is mandatory to ensure a maximum in user outcome.

Gene-expression changes in knee-joint tissues with aging and menopause: implications for the joint as an organ

PubMed Central

Rollick, Natalie C; Lemmex, Devin B; Ono, Yohei; Reno, Carol R; Hart, David A; Lo, Ian KY; Thornton, Gail M

2018-01-01

Background When considering the “joint as an organ”, the tissues in a joint act as complementary components of an organ, and the “set point” is the cellular activity for homeostasis of the joint tissues. Even in the absence of injury, joint tissues have adaptive responses to processes, like aging and menopause, which result in changes to the set point. Purpose The purpose of this study in a preclinical model was to investigate age-related and menopause-related changes in knee-joint tissues with the hypothesis that tissues will change in unique ways that reflect their differing contributions to maintaining joint function (as measured by joint laxity) and the differing processes of aging and menopause. Methods Rabbit knee-joint tissues from three groups were evaluated: young adult (gene expression, n=8; joint laxity, n=7; water content, n=8), aging adult (gene expression, n=6; joint laxity, n=7; water content, n=5), and menopausal adult (gene expression, n=8; joint laxity, n=7; water content, n=8). Surgical menopause was induced with ovariohysterectomy surgery and gene expression was assessed using reverse-transcription quantitative polymerase chain reaction. Results Aging resulted in changes to 37 of the 150 gene–tissue combinations evaluated, and menopause resulted in changes to 39 of the 150. Despite the similar number of changes, only eleven changes were the same in both aging and menopause. No differences in joint laxity were detected comparing young adult rabbits with aging adult rabbits or with menopausal adult rabbits. Conclusion Aging and menopause affected the gene-expression patterns of the tissues of the knee joint differently, suggesting unique changes to the set point of the knee. Interestingly, aging and menopause did not affect knee-joint laxity, suggesting that joint function was maintained, despite changes in gene expression. Taken together, these findings support the theory of the joint as an organ where the tissues of the joint adapt to maintain joint function. PMID:29535510

Single and Multiple Object Tracking Using a Multi-Feature Joint Sparse Representation.

PubMed

Hu, Weiming; Li, Wei; Zhang, Xiaoqin; Maybank, Stephen

2015-04-01

In this paper, we propose a tracking algorithm based on a multi-feature joint sparse representation. The templates for the sparse representation can include pixel values, textures, and edges. In the multi-feature joint optimization, noise or occlusion is dealt with using a set of trivial templates. A sparse weight constraint is introduced to dynamically select the relevant templates from the full set of templates. A variance ratio measure is adopted to adaptively adjust the weights of different features. The multi-feature template set is updated adaptively. We further propose an algorithm for tracking multi-objects with occlusion handling based on the multi-feature joint sparse reconstruction. The observation model based on sparse reconstruction automatically focuses on the visible parts of an occluded object by using the information in the trivial templates. The multi-object tracking is simplified into a joint Bayesian inference. The experimental results show the superiority of our algorithm over several state-of-the-art tracking algorithms.

End-to-End simulations for the MICADO-MAORY SCAO mode

NASA Astrophysics Data System (ADS)

Vidal, Fabrice; Ferreira, Florian; Déo, Vincent; Sevin, Arnaud; Gendron, Eric; Clénet, Yann; Durand, Sébastien; Gratadour, Damien; Doucet, Nicolas; Rousset, Gérard; Davies, Richard

2018-04-01

MICADO is a E-ELT first light near-infrared imager. It will work at the diffraction limit of the telescope thanks to multi-conjugate adaptive optics (MCAO) and single-conjugate adaptive optics (SCAO) modes provided inside the MAORY AO module. The SCAO capability is a joint development by the MICADO and MAORY consortia, lead by MICADO, and is motivated by scientific programs for which SCAO will deliver the best AO performance (e.g. exoplanets, solar system science, bright AGNs, etc). Shack-Hartmann (SH) or Pyramid WFS were both envisioned for the wavefront measurement of the SCAO mode. In addition to WFS design considerations, numerical simulations are therefore needed to trade-off between these two WFS. COMPASS (COMputing Platform for Adaptive optics SyStems) is a GPU-based adaptive optics end-to-end simulation platform allowing us to perform numerical simulations in various modes (SCAO, LTAO, MOAO, MCAO...). COMPASS was originally bound to Yorick for its user interface and a major upgrade has been recently done to now bind to Python allowing a better long term support to the community. Thanks to the speed of computation of COMPASS we were able to span quickly a very large parameters of space at the E-ELT scale. We present the results of the study between WFS choice (SH or Pyramid), WFS parameters (detector noise, guide star magnitude, number of subapertures, number of controlled modes...), turbulence conditions and AO controls for the MICADO-MAORY SCAO mode.

Spatiotemporal Spike Coding of Behavioral Adaptation in the Dorsal Anterior Cingulate Cortex

PubMed Central

Logiaco, Laureline; Quilodran, René; Procyk, Emmanuel; Arleo, Angelo

2015-01-01

The frontal cortex controls behavioral adaptation in environments governed by complex rules. Many studies have established the relevance of firing rate modulation after informative events signaling whether and how to update the behavioral policy. However, whether the spatiotemporal features of these neuronal activities contribute to encoding imminent behavioral updates remains unclear. We investigated this issue in the dorsal anterior cingulate cortex (dACC) of monkeys while they adapted their behavior based on their memory of feedback from past choices. We analyzed spike trains of both single units and pairs of simultaneously recorded neurons using an algorithm that emulates different biologically plausible decoding circuits. This method permits the assessment of the performance of both spike-count and spike-timing sensitive decoders. In response to the feedback, single neurons emitted stereotypical spike trains whose temporal structure identified informative events with higher accuracy than mere spike count. The optimal decoding time scale was in the range of 70–200 ms, which is significantly shorter than the memory time scale required by the behavioral task. Importantly, the temporal spiking patterns of single units were predictive of the monkeys’ behavioral response time. Furthermore, some features of these spiking patterns often varied between jointly recorded neurons. All together, our results suggest that dACC drives behavioral adaptation through complex spatiotemporal spike coding. They also indicate that downstream networks, which decode dACC feedback signals, are unlikely to act as mere neural integrators. PMID:26266537

Thermal design, analysis and comparison on three concepts of space solar power satellite

NASA Astrophysics Data System (ADS)

Yang, Chen; Hou, Xinbin; Wang, Li

2017-08-01

Space solar power satellites (SSPS) have been widely studied as systems for collecting solar energy in space and transmitting it wirelessly to earth. A previously designed planar SSPS concept collects solar power in two huge arrays and then transmits it through one side of the power-conduction joint to the antenna. However, the system's one group of power-conduction joints may induce a single point of failure. As an SSPS concept, the module symmetrical concentrator (MSC) architecture has many advantages. This architecture can help avoid the need for a large, potentially failure-prone conductive rotating joint and limit wiring mass. However, the thermal control system has severely restricted the rapid development of MSC, especially in the sandwich module. Because of the synchronous existence of five suns concentration and solar external heat flux, the sandwich module will have a very high temperature, which will surpass the permissible temperature of the solar cells. Recently, an alternate multi-rotary joints (MR) SSPS concept was designed by the China Academy of Space Technology (CAST). This system has multiple joints to avoid the problem of a single point of failure. Meanwhile, this concept has another advantage for reducing the high power and heat removal in joints. It is well known to us that, because of the huge external flux in SSPS, the thermal management sub-system is an important component that cannot be neglected. Based on the three SSPS concepts, this study investigated the thermal design and analysis of a 1-km, gigawatt-level transmitting antenna in SSPS. This study compares the thermal management sub-systems of power-conduction joints in planar and MR SSPS. Moreover, the study considers three classic thermal control architectures of the MSC's sandwich module: tile, step, and separation. The study also presents an elaborate parameter design, analysis and discussion of step architecture. Finally, the results show the thermal characteristics of each SSPS concept, and the three concepts are compared. The design layouts, analysis results and parameter discussions of the thermal management sub-system proposed in this study can help inform future SSPS thermal designs.

High-order UWB pulses scheme to generate multilevel modulation formats based on incoherent optical sources.

PubMed

Bolea, Mario; Mora, José; Ortega, Beatriz; Capmany, José

2013-11-18

We present a high-order UWB pulses generator based on a microwave photonic filter which provides a set of positive and negative samples by using the slicing of an incoherent optical source and the phase inversion in a Mach-Zehnder modulator. The simple scalability and high reconfigurability of the system permit a better accomplishment of the FCC requirements. Moreover, the proposed scheme permits an easy adaptation to pulse amplitude modulation, bi phase modulation, pulse shape modulation and pulse position modulation. The flexibility of the scheme for being adaptable to multilevel modulation formats permits to increase the transmission bit rate by using hybrid modulation formats.

[The Throwing Shoulder].

PubMed

Wieser, Karl; Gerber, Christian; Meyer, Dominik C

2016-02-03

Repetitive top-performance of overhead athletes induces a tremendous stress for the throwing shoulder. Throwers reach rotational speed of their arm of more than 7000°/s with joint compression and distraction forces of more than 1000 N. This performance is tributary to adaption of the shoulder muscles and the joint itself. These adaptions may, however lead to two specific problems of the throwing shoulder: 1. The posterosuperior internal impingement of the rotator cuff and labrum between glenoid and humeral head during late cooking phase; 2. A decreased internal rotation of the glenohumeral joint (GIRD) with compensatory problems of the scapula-stabilizing muscles. Precise analysis of kinematics and pathomechanics aims to improve understanding and treatment of those specific problems of the throwing shoulder.

Study on a low complexity adaptive modulation algorithm in OFDM-ROF system with sub-carrier grouping technology

NASA Astrophysics Data System (ADS)

Liu, Chong-xin; Liu, Bo; Zhang, Li-jia; Xin, Xiang-jun; Tian, Qing-hua; Tian, Feng; Wang, Yong-jun; Rao, Lan; Mao, Yaya; Li, Deng-ao

2018-01-01

During the last decade, the orthogonal frequency division multiplexing radio-over-fiber (OFDM-ROF) system with adaptive modulation technology is of great interest due to its capability of raising the spectral efficiency dramatically, reducing the effects of fiber link or wireless channel, and improving the communication quality. In this study, according to theoretical analysis of nonlinear distortion and frequency selective fading on the transmitted signal, a low-complexity adaptive modulation algorithm is proposed in combination with sub-carrier grouping technology. This algorithm achieves the optimal performance of the system by calculating the average combined signal-to-noise ratio of each group and dynamically adjusting the origination modulation format according to the preset threshold and user's requirements. At the same time, this algorithm takes the sub-carrier group as the smallest unit in the initial bit allocation and the subsequent bit adjustment. So, the algorithm complexity is only 1 /M (M is the number of sub-carriers in each group) of Fischer algorithm, which is much smaller than many classic adaptive modulation algorithms, such as Hughes-Hartogs algorithm, Chow algorithm, and is in line with the development direction of green and high speed communication. Simulation results show that the performance of OFDM-ROF system with the improved algorithm is much better than those without adaptive modulation, and the BER of the former achieves 10e1 to 10e2 times lower than the latter when SNR values gets larger. We can obtain that this low complexity adaptive modulation algorithm is extremely useful for the OFDM-ROF system.

Altered paracrine signaling from the injured knee joint impairs postnatal long bone growth

PubMed Central

Roselló-Díez, Alberto; Stephen, Daniel; Joyner, Alexandra L

2017-01-01

Regulation of organ growth is a poorly understood process. In the long bones, the growth plates (GPs) drive elongation by generating a scaffold progressively replaced by bone. Although studies have focused on intrinsic GP regulation, classic and recent experiments suggest that local signals also modulate GP function. We devised a genetic mouse model to study extrinsic long bone growth modulation, in which injury is specifically induced in the left hindlimb, such that the right hindlimb serves as an internal control. Remarkably, when only mesenchyme cells surrounding postnatal GPs were killed, left bone growth was nevertheless reduced. GP signaling was impaired by altered paracrine signals from the knee joint, including activation of the injury response and, in neonates, dampened IGF1 production. Importantly, only the combined prevention of both responses rescued neonatal growth. Thus, we identified signals from the knee joint that modulate bone growth and could underlie establishment of body proportions. DOI: http://dx.doi.org/10.7554/eLife.27210.001 PMID:28741471

Adaptive dynamic surface control of flexible-joint robots using self-recurrent wavelet neural networks.

PubMed

Yoo, Sung Jin; Park, Jin Bae; Choi, Yoon Ho

2006-12-01

A new method for the robust control of flexible-joint (FJ) robots with model uncertainties in both robot dynamics and actuator dynamics is proposed. The proposed control system is a combination of the adaptive dynamic surface control (DSC) technique and the self-recurrent wavelet neural network (SRWNN). The adaptive DSC technique provides the ability to overcome the "explosion of complexity" problem in backstepping controllers. The SRWNNs are used to observe the arbitrary model uncertainties of FJ robots, and all their weights are trained online. From the Lyapunov stability analysis, their adaptation laws are induced, and the uniformly ultimately boundedness of all signals in a closed-loop adaptive system is proved. Finally, simulation results for a three-link FJ robot are utilized to validate the good position tracking performance and robustness against payload uncertainties and external disturbances of the proposed control system.

KSC-01pp1185

NASA Image and Video Library

2001-06-21

KENNEDY SPACE CENTER, Fla. -- Atop the mobile launcher platform, Space Shuttle Atlantis, with its orange external tank and white solid rocket boosters, sits on Launch Pad 39B after rollout from the Vehicle Assembly Building. Seen on either side of the orbiter’s tail are the tail service masts. They support the fluid, gas and electrical requirements of the orbiter’s liquid oxygen and liquid hydrogen aft umbilicals. The Shuttle is targeted for launch no earlier than July 12 on mission STS-104, the 10th flight to the International Space Station. The payload on the 11-day mission is the Joint Airlock Module, which will allow astronauts and cosmonauts in residence on the Station to perform future spacewalks without the presence of a Space Shuttle. The module, which comprises a crew lock and an equipment lock, will be connected to the starboard (right) side of Node 1 Unity. Atlantis will also carry oxygen and nitrogen storage tanks, vital to operation of the Joint Airlock, on a Spacelab Logistics Double Pallet in the payload bay. The tanks, to be installed on the perimeter of the Joint Module during the mission’s spacewalks, will support future spacewalk operations and experiments plus augment the resupply system for the Station’s Service Module

KSC-01pp1184

NASA Image and Video Library

2001-06-21

KENNEDY SPACE CENTER, Fla. -- Atop the mobile launcher platform, Space Shuttle Atlantis arrives on Launch Pad 39B after rollout from the Vehicle Assembly Building. Seen on either side of the orbiter’s tail are the tail service masts. They support the fluid, gas and electrical requirements of the orbiter’s liquid oxygen and liquid hydrogen aft umbilicals. The Shuttle is targeted for launch no earlier than July 12 on mission STS-104, the 10th flight to the International Space Station. The payload on the 11-day mission is the Joint Airlock Module, which will allow astronauts and cosmonauts in residence on the Station to perform future spacewalks without the presence of a Space Shuttle. The module, which comprises a crew lock and an equipment lock, will be connected to the starboard (right) side of Node 1 Unity. Atlantis will also carry oxygen and nitrogen storage tanks, vital to operation of the Joint Airlock, on a Spacelab Logistics Double Pallet in the payload bay. The tanks, to be installed on the perimeter of the Joint Module during the mission’s spacewalks, will support future spacewalk operations and experiments plus augment the resupply system for the Station’s Service Module

Space Shuttle Atlantis is on Launch Pad 39B

NASA Technical Reports Server (NTRS)

2001-01-01

KENNEDY SPACE CENTER, Fla. -- Atop the mobile launcher platform, Space Shuttle Atlantis, with its orange external tank and white solid rocket boosters, sits on Launch Pad 39B after rollout from the Vehicle Assembly Building. Seen on either side of the orbiters tail are the tail service masts. They support the fluid, gas and electrical requirements of the orbiters liquid oxygen and liquid hydrogen aft umbilicals. The Shuttle is targeted for launch no earlier than July 12 on mission STS-104, the 10th flight to the International Space Station. The payload on the 11- day mission is the Joint Airlock Module, which will allow astronauts and cosmonauts in residence on the Station to perform future spacewalks without the presence of a Space Shuttle. The module, which comprises a crew lock and an equipment lock, will be connected to the starboard (right) side of Node 1 Unity. Atlantis will also carry oxygen and nitrogen storage tanks, vital to operation of the Joint Airlock, on a Spacelab Logistics Double Pallet in the payload bay. The tanks, to be installed on the perimeter of the Joint Module during the missions spacewalks, will support future spacewalk operations and experiments plus augment the resupply system for the Stations Service Module.

Space Shuttle Atlantis is on Launch Pad 39B

NASA Technical Reports Server (NTRS)

2001-01-01

KENNEDY SPACE CENTER, Fla. -- Atop the mobile launcher platform, Space Shuttle Atlantis arrives on Launch Pad 39B after rollout from the Vehicle Assembly Building. Seen on either side of the orbiters tail are the tail service masts. They support the fluid, gas and electrical requirements of the orbiters liquid oxygen and liquid hydrogen aft umbilicals. The Shuttle is targeted for launch no earlier than July 12 on mission STS-104, the 10th flight to the International Space Station. The payload on the 11- day mission is the Joint Airlock Module, which will allow astronauts and cosmonauts in residence on the Station to perform future spacewalks without the presence of a Space Shuttle. The module, which comprises a crew lock and an equipment lock, will be connected to the starboard (right) side of Node 1 Unity. Atlantis will also carry oxygen and nitrogen storage tanks, vital to operation of the Joint Airlock, on a Spacelab Logistics Double Pallet in the payload bay. The tanks, to be installed on the perimeter of the Joint Module during the missions spacewalks, will support future spacewalk operations and experiments plus augment the resupply system for the Stations Service Module.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wexler, Jason; Botkin, Jonathan; Culligan, Matthew

A mounting support for a photovoltaic module is described. The mounting support includes a pedestal having a surface adaptable to receive a flat side of a photovoltaic module laminate. A hole is disposed in the pedestal, the hole adaptable to receive a bolt or a pin used to couple the pedestal to the flat side of the photovoltaic module laminate.

Spatial Selection and Local Adaptation Jointly Shape Life-History Evolution during Range Expansion.

PubMed

Van Petegem, Katrien H P; Boeye, Jeroen; Stoks, Robby; Bonte, Dries

2016-11-01

In the context of climate change and species invasions, range shifts increasingly gain attention because the rates at which they occur in the Anthropocene induce rapid changes in biological assemblages. During range shifts, species experience multiple selection pressures. For poleward expansions in particular, it is difficult to interpret observed evolutionary dynamics because of the joint action of evolutionary processes related to spatial selection and to adaptation toward local climatic conditions. To disentangle the effects of these two processes, we integrated stochastic modeling and data from a common garden experiment, using the spider mite Tetranychus urticae as a model species. By linking the empirical data with those derived form a highly parameterized individual-based model, we infer that both spatial selection and local adaptation contributed to the observed latitudinal life-history divergence. Spatial selection best described variation in dispersal behavior, while variation in development was best explained by adaptation to the local climate. Divergence in life-history traits in species shifting poleward could consequently be jointly determined by contemporary evolutionary dynamics resulting from adaptation to the environmental gradient and from spatial selection. The integration of modeling with common garden experiments provides a powerful tool to study the contribution of these evolutionary processes on life-history evolution during range expansion.

It Is Not What You Expect: Dissociating Conflict Adaptation from Expectancies in a Stroop Task

ERIC Educational Resources Information Center

Jimenez, Luis; Mendez, Amavia

2013-01-01

In conflict tasks, congruency effects are modulated by the sequence of preceding trials. This modulation effect has been interpreted as an influence of a proactive mechanism of adaptation to conflict (Botvinick, Nystrom, Fissell, Carter, & Cohen, 1999), but the possible contribution of explicit expectancies to this adaptation effect remains…

The Joint CCSDS-SFCG Modulation Study--A Comparison of Modulation Schemes

NASA Technical Reports Server (NTRS)

Martin, W. L.; Nguyen, T. M.

1994-01-01

This paper compares the various modulation schemes, namely, PCM/PSK/PM, PCM/PM and BPSK. The subcarrier wave form for PCM/PSK/PM can be either square wave or sine wave, and the data format for PCM/PM and BPSK can be wither NRZ or Bi-phase.

The Joint Airlock Module is moved to the payload canister

NASA Technical Reports Server (NTRS)

2001-01-01

KENNEDY SPACE CENTER, Fla. -- In the Space Station Processing Facility, the Joint Airlock Module is moved closer to the payload canister. The airlock will be installed in the payload bay of Atlantis for mission STS-104 to the International Space Station. The airlock is a pressurized flight element consisting of two cylindrical chambers attached end-to-end by a connecting bulkhead and hatch. Once installed and activated, the Airlock becomes the primary path for spacewalk entry to and departure from the Space Station for U.S. spacesuits, which are known as Extravehicular Mobility Units, or EMUs. In addition, the Joint Airlock is designed to support the Russian Orlan spacesuit for EVA activity. STS-104 is scheduled for launch June 14 from Launch Pad 39B.

Synergistic Approach Integrating Joint Capabilities for USSOCOM Contingency Contracting: Construction Management Module

DTIC Science & Technology

2010-12-01

59 a. The Joint Uniform Lessons Learned System (JULLS) .........59 b. Acquisition Community Connection (ACC) ..........................59 c...Report ACC Acquisition Community Connection ADDIE Analyze, Design, Develop, Implement, Evaluate AFFARS Air Force Federal Acquisition Regulation...Operations J4 Logistics J5 Plans J6 Communications J8 Programming and Comptroller J&A Justification and Approval JARB Joint Acquisition

Experimental Investigation into the Fatigue Life of Hybrid Joints Under Fully Reversed Flexure Loading

DTIC Science & Technology

2008-06-01

joint classification 3 b. Hot spot-stress approach c. Notch-stress approach * d. Mesh-insensitive approach 2. Fracture mechanics (used for crack... classification approach, which is an adaptation of the nominal stress approach just discussed, with the welded joint fatigue curves as given in Table...used. More detail is provided on the joint classifications , and -- 19 I graphic representations are also included. It is explained that the stress

Astronaut Vance Brand seen in hatchway leading to Apollo Docking module

NASA Technical Reports Server (NTRS)

1975-01-01

Astronaut Vance D. Brand, command module pilot of the American Apollo Soyuz Test Project (ASTP) crew, is seen in the hatchway leading from the Apollo Command Module (CM) into the Apollo Docking Module (DM) during joint U.S.-USSR ASTP docking in Earth orbit mission. The 35mm camera is looking from the DM into the CM.

Identification of Nonlinear Micron-Level Mechanics for a Precision Deployable Joint

NASA Technical Reports Server (NTRS)

Bullock, S. J.; Peterson, L. D.

1994-01-01

The experimental identification of micron-level nonlinear joint mechanics and dynamics for a pin-clevis joint used in a precision, adaptive, deployable space structure are investigated. The force-state mapping method is used to identify the behavior of the joint under a preload. The results of applying a single tension-compression cycle to the joint under a tensile preload are presented. The observed micron-level behavior is highly nonlinear and involves all six rigid body motion degrees-of-freedom of the joint. it is also suggests that at micron levels of motion modelling of the joint mechanics and dynamics must include the interactions between all internal components, such as the pin, bushings, and the joint node.

Passive Joint Forces Are Tuned to Limb Use in Insects and Drive Movements without Motor Activity

PubMed Central

Ache, Jan M.; Matheson, Thomas

2013-01-01

Summary Background Limb movements are generally driven by active muscular contractions working with and against passive forces arising in muscles and other structures. In relatively heavy limbs, the effects of gravity and inertia predominate, whereas in lighter limbs, passive forces intrinsic to the limb are of greater consequence. The roles of passive forces generated by muscles and tendons are well understood, but there has been little recognition that forces originating within joints themselves may also be important, and less still that these joint forces may be adapted through evolution to complement active muscle forces acting at the same joint. Results We examined the roles of passive joint forces in insect legs with different arrangements of antagonist muscles. We first show that passive forces modify actively generated movements of a joint across its working range, and that they can be sufficiently strong to generate completely passive movements that are faster than active movements observed in natural behaviors. We further demonstrate that some of these forces originate within the joint itself. In legs of different species adapted to different uses (walking, jumping), these passive joint forces complement the balance of strength of the antagonist muscles acting on the joint. We show that passive joint forces are stronger where they assist the weaker of two antagonist muscles. Conclusions In limbs where the dictates of a key behavior produce asymmetry in muscle forces, passive joint forces can be coadapted to provide the balance needed for the effective generation of other behaviors. PMID:23871240

[Temporo-mandibular joint. Morpho-functional considerations].

PubMed

Scutariu, M D; Indrei, Anca

2004-01-01

The temporo-mandibular joint is distinguished from most other synovial joints of the body by two features: 1. the two jointed components carry teeth whose position and occlusion introduce a very strong influence on the movements of the temporo-mandibular joint and 2. its articular surfaces are not covered by hyaline cartilage, but by a dense, fibrous tissue. This paper describes the parts of the temporo-mandibular joint: the articular surfaces (the condylar process of the mandible and the glenoid part of the temporal bone), the fibrocartilaginous disc which is interposed between the mandibular and the temporal surface, the fibrous capsule of the temporo-mandibular joint and the ligaments of this joint. All these parts present a very strong adaptation at the important functions of the temporo-mandibular joint.

Advanced composites structural concepts and materials technologies for primary aircraft structures: Structural response and failure analysis

NASA Technical Reports Server (NTRS)

Dorris, William J.; Hairr, John W.; Huang, Jui-Tien; Ingram, J. Edward; Shah, Bharat M.

1992-01-01

Non-linear analysis methods were adapted and incorporated in a finite element based DIAL code. These methods are necessary to evaluate the global response of a stiffened structure under combined in-plane and out-of-plane loading. These methods include the Arc Length method and target point analysis procedure. A new interface material model was implemented that can model elastic-plastic behavior of the bond adhesive. Direct application of this method is in skin/stiffener interface failure assessment. Addition of the AML (angle minus longitudinal or load) failure procedure and Hasin's failure criteria provides added capability in the failure predictions. Interactive Stiffened Panel Analysis modules were developed as interactive pre-and post-processors. Each module provides the means of performing self-initiated finite elements based analysis of primary structures such as a flat or curved stiffened panel; a corrugated flat sandwich panel; and a curved geodesic fuselage panel. This module brings finite element analysis into the design of composite structures without the requirement for the user to know much about the techniques and procedures needed to actually perform a finite element analysis from scratch. An interactive finite element code was developed to predict bolted joint strength considering material and geometrical non-linearity. The developed method conducts an ultimate strength failure analysis using a set of material degradation models.

Multiplatform Mission Planning and Operations Simulation Environment for Adaptive Remote Sensors

NASA Astrophysics Data System (ADS)

Smith, G.; Ball, C.; O'Brien, A.; Johnson, J. T.

2017-12-01

We report on the design and development of mission simulator libraries to support the emerging field of adaptive remote sensors. We will outline the current state of the art in adaptive sensing, provide analysis of how the current approach to performing observing system simulation experiments (OSSEs) must be changed to enable adaptive sensors for remote sensing, and present an architecture to enable their inclusion in future OSSEs.The growing potential of sensors capable of real-time adaptation of their operational parameters calls for a new class of mission planning and simulation tools. Existing simulation tools used in OSSEs assume a fixed set of sensor parameters in terms of observation geometry, frequencies used, resolution, or observation time, which allows simplifications to be made in the simulation and allows sensor observation errors to be characterized a priori. Adaptive sensors may vary these parameters depending on the details of the scene observed, so that sensor performance is not simple to model without conducting OSSE simulations that include sensor adaptation in response to varying observational environment. Adaptive sensors are of significance to resource-constrained, small satellite platforms because they enable the management of power and data volumes while providing methods for multiple sensors to collaborate.The new class of OSSEs required to utilize adaptive sensors located on multiple platforms must answer the question: If the physical act of sensing has a cost, how does the system determine if the science value of a measurement is worth the cost and how should that cost be shared among the collaborating sensors?Here we propose to answer this question using an architecture structured around three modules: ADAPT, MANAGE and COLLABORATE. The ADAPT module is a set of routines to facilitate modeling of adaptive sensors, the MANAGE module will implement a set of routines to facilitate simulations of sensor resource management when power and data volume are constrained, and the COLLABORATE module will support simulations of coordination among multiple platforms with adaptive sensors. When used together these modules will for a simulation OSSEs that can enable both the design of adaptive algorithms to support remote sensing and the prediction of the sensor performance.

Estimation of Time-Varying, Intrinsic and Reflex Dynamic Joint Stiffness during Movement. Application to the Ankle Joint

PubMed Central

Guarín, Diego L.; Kearney, Robert E.

2017-01-01

Dynamic joint stiffness determines the relation between joint position and torque, and plays a vital role in the control of posture and movement. Dynamic joint stiffness can be quantified during quasi-stationary conditions using disturbance experiments, where small position perturbations are applied to the joint and the torque response is recorded. Dynamic joint stiffness is composed of intrinsic and reflex mechanisms that act and change together, so that nonlinear, mathematical models and specialized system identification techniques are necessary to estimate their relative contributions to overall joint stiffness. Quasi-stationary experiments have demonstrated that dynamic joint stiffness is heavily modulated by joint position and voluntary torque. Consequently, during movement, when joint position and torque change rapidly, dynamic joint stiffness will be Time-Varying (TV). This paper introduces a new method to quantify the TV intrinsic and reflex components of dynamic joint stiffness during movement. The algorithm combines ensemble and deterministic approaches for estimation of TV systems; and uses a TV, parallel-cascade, nonlinear system identification technique to separate overall dynamic joint stiffness into intrinsic and reflex components from position and torque records. Simulation studies of a stiffness model, whose parameters varied with time as is expected during walking, demonstrated that the new algorithm accurately tracked the changes in dynamic joint stiffness using as little as 40 gait cycles. The method was also used to estimate the intrinsic and reflex dynamic ankle stiffness from an experiment with a healthy subject during which ankle movements were imposed while the subject maintained a constant muscle contraction. The method identified TV stiffness model parameters that predicted the measured torque very well, accounting for more than 95% of its variance. Moreover, both intrinsic and reflex dynamic stiffness were heavily modulated through the movement in a manner that could not be predicted from quasi-stationary experiments. The new method provides the tool needed to explore the role of dynamic stiffness in the control of movement. PMID:28649196

Joint OSNR monitoring and modulation format identification in digital coherent receivers using deep neural networks.

PubMed

Khan, Faisal Nadeem; Zhong, Kangping; Zhou, Xian; Al-Arashi, Waled Hussein; Yu, Changyuan; Lu, Chao; Lau, Alan Pak Tao

2017-07-24

We experimentally demonstrate the use of deep neural networks (DNNs) in combination with signals' amplitude histograms (AHs) for simultaneous optical signal-to-noise ratio (OSNR) monitoring and modulation format identification (MFI) in digital coherent receivers. The proposed technique automatically extracts OSNR and modulation format dependent features of AHs, obtained after constant modulus algorithm (CMA) equalization, and exploits them for the joint estimation of these parameters. Experimental results for 112 Gbps polarization-multiplexed (PM) quadrature phase-shift keying (QPSK), 112 Gbps PM 16 quadrature amplitude modulation (16-QAM), and 240 Gbps PM 64-QAM signals demonstrate OSNR monitoring with mean estimation errors of 1.2 dB, 0.4 dB, and 1 dB, respectively. Similarly, the results for MFI show 100% identification accuracy for all three modulation formats. The proposed technique applies deep machine learning algorithms inside standard digital coherent receiver and does not require any additional hardware. Therefore, it is attractive for cost-effective multi-parameter estimation in next-generation elastic optical networks (EONs).

Effects of threshold on single-target detection by using modified amplitude-modulated joint transform correlator

NASA Astrophysics Data System (ADS)

Kaewkasi, Pitchaya; Widjaja, Joewono; Uozumi, Jun

2007-03-01

Effects of threshold value on detection performance of the modified amplitude-modulated joint transform correlator are quantitatively studied using computer simulation. Fingerprint and human face images are used as test scenes in the presence of noise and a contrast difference. Simulation results demonstrate that this correlator improves detection performance for both types of image used, but moreso for human face images. Optimal detection of low-contrast human face images obscured by strong noise can be obtained by selecting an appropriate threshold value.

Distributed Control by Lagrangian Steepest Descent

NASA Technical Reports Server (NTRS)

Wolpert, David H.; Bieniawski, Stefan

2004-01-01

Often adaptive, distributed control can be viewed as an iterated game between independent players. The coupling between the players mixed strategies, arising as the system evolves from one instant to the next, is determined by the system designer. Information theory tells us that the most likely joint strategy of the players, given a value of the expectation of the overall control objective function, is the minimizer of a function o the joint strategy. So the goal of the system designer is to speed evolution of the joint strategy to that Lagrangian mhimbhgpoint,lowerthe expectated value of the control objective function, and repeat Here we elaborate the theory of algorithms that do this using local descent procedures, and that thereby achieve efficient, adaptive, distributed control.

Lonchakov holds Space Science P/L Kristallizator Module-1 experiment hardware in the SM during Joint Operations

NASA Image and Video Library

2008-10-15

ISS017-E-018411 (15 Oct. 2008) --- Russian Federal Space Agency cosmonaut Yury Lonchakov, Expedition 18 flight engineer, looks over a procedures checklist while holding Space Science P/L Crystallizer Module-1 experiment hardware in the Zvezda Service Module of the International Space Station.

Mir Mission Chronicle

NASA Technical Reports Server (NTRS)

McDonald, Sue

1998-01-01

Dockings, module additions, configuration changes, crew changes, and major mission events are tracked for Mir missions 17 through 21 (November 1994 through August 1996). The international aspects of these missions are presented, comprising joint missions with ESA and NASA, including three U.S. Space Shuttle dockings. New Mir modules described are Spektr, the Docking Module, and Priroda.

Investigation of Stimulation-Response Relationships for Complex Fracture Systems in Enhanced Geothermal Reservoirs

DOE Data Explorer

Fu, Pengcheng; Johnson, Scott M.; Carrigan, Charles R.

2011-01-01

Hydraulic fracturing is currently the primary method for stimulating low-permeability geothermal reservoirs and creating Enhanced (or Engineered) Geothermal Systems (EGS) with improved permeability and heat production efficiency. Complex natural fracture systems usually exist in the formations to be stimulated and it is therefore critical to understand the interactions between existing fractures and newly created fractures before optimal stimulation strategies can be developed. Our study aims to improve the understanding of EGS stimulation-response relationships by developing and applying computer-based models that can effectively reflect the key mechanisms governing interactions between complex existing fracture networks and newly created hydraulic fractures. In this paper, we first briefly describe the key modules of our methodology, namely a geomechanics solver, a discrete fracture flow solver, a rock joint response model, an adaptive remeshing module, and most importantly their effective coupling. After verifying the numerical model against classical closed-form solutions, we investigate responses of reservoirs with different preexisting natural fractures to a variety of stimulation strategies. The factors investigated include: the in situ stress states (orientation of the principal stresses and the degree of stress anisotropy), pumping pressure, and stimulation sequences of multiple wells.

A Wideband Satcom Based Avionics Network with CDMA Uplink and TDM Downlink

NASA Technical Reports Server (NTRS)

Agrawal, D.; Johnson, B. S.; Madhow, U.; Ramchandran, K.; Chun, K. S.

2000-01-01

The purpose of this paper is to describe some key technical ideas behind our vision of a future satcom based digital communication network for avionics applications The key features of our design are as follows: (a) Packetized transmission to permit efficient use of system resources for multimedia traffic; (b) A time division multiplexed (TDM) satellite downlink whose physical layer is designed to operate the satellite link at maximum power efficiency. We show how powerful turbo codes (invented originally for linear modulation) can be used with nonlinear constant envelope modulation, thus permitting the satellite amplifier to operate in a power efficient nonlinear regime; (c) A code division multiple access (CDMA) satellite uplink, which permits efficient access to the satellite from multiple asynchronous users. Closed loop power control is difficult for bursty packetized traffic, especially given the large round trip delay to the satellite. We show how adaptive interference suppression techniques can be used to deal with the ensuing near-far problem; (d) Joint source-channel coding techniques are required both at the physical and the data transport layer to optimize the end-to-end performance. We describe a novel approach to multiple description image encoding at the data transport layer in this paper.

Neuropeptide F neurons modulate sugar reward during associative olfactory learning of Drosophila larvae.

PubMed

Rohwedder, Astrid; Selcho, Mareike; Chassot, Bérénice; Thum, Andreas S

2015-12-15

All organisms continuously have to adapt their behavior according to changes in the environment in order to survive. Experience-driven changes in behavior are usually mediated and maintained by modifications in signaling within defined brain circuits. Given the simplicity of the larval brain of Drosophila and its experimental accessibility on the genetic and behavioral level, we analyzed if Drosophila neuropeptide F (dNPF) neurons are involved in classical olfactory conditioning. dNPF is an ortholog of the mammalian neuropeptide Y, a highly conserved neuromodulator that stimulates food-seeking behavior. We provide a comprehensive anatomical analysis of the dNPF neurons on the single-cell level. We demonstrate that artificial activation of dNPF neurons inhibits appetitive olfactory learning by modulating the sugar reward signal during acquisition. No effect is detectable for the retrieval of an established appetitive olfactory memory. The modulatory effect is based on the joint action of three distinct cell types that, if tested on the single-cell level, inhibit and invert the conditioned behavior. Taken together, our work describes anatomically and functionally a new part of the sugar reinforcement signaling pathway for classical olfactory conditioning in Drosophila larvae. © 2015 Wiley Periodicals, Inc.

Graph theory in brain-to-brain connectivity: A simulation study and an application to an EEG hyperscanning experiment.

PubMed

Toppi, J; Ciaramidaro, A; Vogel, P; Mattia, D; Babiloni, F; Siniatchkin, M; Astolfi, L

2015-08-01

Hyperscanning consists in the simultaneous recording of hemodynamic or neuroelectrical signals from two or more subjects acting in a social context. Well-established methodologies for connectivity estimation have already been adapted to hyperscanning purposes. The extension of graph theory approach to multi-subjects case is still a challenging issue. In the present work we aim to test the ability of the currently used graph theory global indices in describing the properties of a network given by two interacting subjects. The testing was conducted first on surrogate brain-to-brain networks reproducing typical social scenarios and then on real EEG hyperscanning data recorded during a Joint Action task. The results of the simulation study highlighted the ability of all the investigated indexes in modulating their values according to the level of interaction between subjects. However, only global efficiency and path length indexes demonstrated to be sensitive to an asymmetry in the communication between the two subjects. Such results were, then, confirmed by the application on real EEG data. Global efficiency modulated, in fact, their values according to the inter-brain density, assuming higher values in the social condition with respect to the non-social condition.

The Computerized Adaptive Testing System Development Project.

ERIC Educational Resources Information Center

McBride, James R.; Sympson, J. B.

The Computerized Adaptive Testing (CAT) project is a joint Armed Services coordinated effort to develop and evaluate a system for automated, adaptive administration of the Armed Services Vocational Aptitude Battery (ASVAB). The CAT is a system for administering personnel tests that differs from conventional test administration in two major…

Embedded diagnostic, prognostic, and health management system and method for a humanoid robot

NASA Technical Reports Server (NTRS)

Barajas, Leandro G. (Inventor); Strawser, Philip A (Inventor); Sanders, Adam M (Inventor); Reiland, Matthew J (Inventor)

2013-01-01

A robotic system includes a humanoid robot with multiple compliant joints, each moveable using one or more of the actuators, and having sensors for measuring control and feedback data. A distributed controller controls the joints and other integrated system components over multiple high-speed communication networks. Diagnostic, prognostic, and health management (DPHM) modules are embedded within the robot at the various control levels. Each DPHM module measures, controls, and records DPHM data for the respective control level/connected device in a location that is accessible over the networks or via an external device. A method of controlling the robot includes embedding a plurality of the DPHM modules within multiple control levels of the distributed controller, using the DPHM modules to measure DPHM data within each of the control levels, and recording the DPHM data in a location that is accessible over at least one of the high-speed communication networks.

Method of joint bit rate/modulation format identification and optical performance monitoring using asynchronous delay-tap sampling for radio-over-fiber systems

NASA Astrophysics Data System (ADS)

Guesmi, Latifa; Menif, Mourad

2016-08-01

In the context of carrying a wide variety of modulation formats and data rates for home networks, the study covers the radio-over-fiber (RoF) technology, where the need for an alternative way of management, automated fault diagnosis, and formats identification is expressed. Also, RoF signals in an optical link are impaired by various linear and nonlinear effects including chromatic dispersion, polarization mode dispersion, amplified spontaneous emission noise, and so on. Hence, for this purpose, we investigated the sampling method based on asynchronous delay-tap sampling in conjunction with a cross-correlation function for the joint bit rate/modulation format identification and optical performance monitoring. Three modulation formats with different data rates are used to demonstrate the validity of this technique, where the identification accuracy and the monitoring ranges reached high values.

Arboreal Day Geckos (Phelsuma madagascariensis) Differentially Modulate Fore- and Hind Limb Kinematics in Response to Changes in Habitat Structure

PubMed Central

Zhuang, Mingna V.; Higham, Timothy E.

2016-01-01

By using adhesion, geckos can move through incredibly challenging habitats. However, continually changing terrain may necessitate modulation of the adhesive apparatus in order to maximize its effectiveness over a range of challenges. Behaviorally modulating how the adhesive system is applied can occur by altering the alignment of the foot relative to the long axis of the body and/or the angles between the digits (interdigital angle). Given the directionality of the adhesive system, geckos likely vary the application of the system via these mechanisms as they run. We quantified 3D movements (using high-speed video) of the day gecko, Phelsuma madagascariensis, running on a range of ecologically relevant inclines (0°, 45°, 90°) and perch diameters (1.5 cm, 10 cm and broad). We measured the instantaneous sum of interdigital angles and foot alignment relative to the body, as well as other kinematic variables, throughout each stride and across treatments. Modulation of foot alignment at 45° and 90° was similar between the forelimb and hind limb, but differed at 0°, suggesting that P. madagascariensis is able to exert an adhesive force using multiple strategies. Both the sum of interdigital angles and alignment in the fore- and hind foot were modulated. Differences in modulation between the limbs are likely related to the underlying morphology. The modulation of interdigital angle and foot alignment suggests that aspects other than the mechanism of adhesion, such as joint morphology, are important for arboreal movement in geckos. Our study of foot usage in arboreal locomotion reveals patterns that may be widespread across pad-bearing lizards. In addition to understanding the constraints exerted by the adhesive apparatus, we highlight how biomechanical traits may respond to the evolution of novel adaptations and morphologies. PMID:27145027

The Joint Airlock Module is moved to the payload canister

NASA Technical Reports Server (NTRS)

2001-01-01

KENNEDY SPACE CENTER, Fla. -- In the Space Station Processing Facility, workers standing inside the payload canister help guide the Joint Airlock Module into place. The airlock will be installed in the payload bay of Atlantis for mission STS-104 to the International Space Station. The airlock is a pressurized flight element consisting of two cylindrical chambers attached end-to-end by a connecting bulkhead and hatch. Once installed and activated, the Airlock becomes the primary path for spacewalk entry to and departure from the Space Station for U.S. spacesuits, which are known as Extravehicular Mobility Units, or EMUs. In addition, the Joint Airlock is designed to support the Russian Orlan spacesuit for EVA activity. STS-104 is scheduled for launch June 14 from Launch Pad 39B.

The Joint Airlock Module is moved to the payload canister

NASA Technical Reports Server (NTRS)

2001-01-01

KENNEDY SPACE CENTER, Fla. -- In the Space Station Processing Facility, the Joint Airlock Module is lifted from its workstand for a transfer to the payload canister. The airlock will be installed in the payload bay of Atlantis for mission STS-104 to the International Space Station. The airlock is a pressurized flight element consisting of two cylindrical chambers attached end-to-end by a connecting bulkhead and hatch. Once installed and activated, the airlock becomes the primary path for spacewalk entry to and departure from the Space Station for U.S. spacesuits, which are known as Extravehicular Mobility Units, or EMUs. In addition, the Joint Airlock is designed to support the Russian Orlan spacesuit for EVA activity. STS-104 is scheduled for launch June 14 from Launch Pad 39B.

Revision and Validation of a Culturally-Adapted Online Instructional Module Using Edmundson's CAP Model: A DBR Study

ERIC Educational Resources Information Center

Tapanes, Marie A.

2011-01-01

In the present study, the Cultural Adaptation Process Model was applied to an online module to include adaptations responsive to the online students' culturally-influenced learning styles and preferences. The purpose was to provide the online learners with a variety of course material presentations, where the e-learners had the opportunity to…

BUILDING MODEL ANALYSIS APPLICATIONS WITH THE JOINT UNIVERSAL PARAMETER IDENTIFICATION AND EVALUATION OF RELIABILITY (JUPITER) API

EPA Science Inventory

The open-source, public domain JUPITER (Joint Universal Parameter IdenTification and Evaluation of Reliability) API (Application Programming Interface) provides conventions and Fortran-90 modules to develop applications (computer programs) for analyzing process models. The input ...

Joint transform correlators with spatially incoherent illumination

NASA Astrophysics Data System (ADS)

Bykovsky, Yuri A.; Karpiouk, Andrey B.; Markilov, Anatoly A.; Rodin, Vladislav G.; Starikov, Sergey N.

1997-03-01

Two variants of joint transform correlators with monochromatic spatially incoherent illumination are considered. The Fourier-holograms of the reference and recognized images are recorded simultaneously or apart in a time on the same spatial light modulator directly by monochromatic spatially incoherent light. To create the signal of mutual correlation of the images it is necessary to execute nonlinear transformation when the hologram is illuminated by coherent light. In the first scheme of the correlator this aim was achieved by using double pas of a restoring coherent wave through the hologram. In the second variant of the correlator the non-linearity of the characteristic of the spatial light modulator for hologram recording was used. Experimental schemes and results on processing teste images by both variants of joint transform correlators with monochromatic spatially incoherent illumination. The use of spatially incoherent light on the input of joint transform correlators permits to reduce the requirements to optical quality of elements, to reduce accuracy requirements on elements positioning and to expand a number of devices suitable to input images in correlators.

Modulation between high- and low-frequency transcutaneous electric nerve stimulation delays the development of analgesic tolerance in arthritic rats.

PubMed

Desantana, Josimari M; Santana-Filho, Valter J; Sluka, Kathleen A

2008-04-01

To investigate whether repeated administration of modulating frequency transcutaneous electric nerve stimulation (TENS) prevents development of analgesic tolerance. Knee joint inflammation (3% carrageenan and kaolin) was induced in rats. Either mixed or alternating frequency was administered daily (20min) for 2 weeks to the inflamed knee under light halothane anesthesia (1%-2%). Laboratory. Adult male Sprague-Dawley rats (N=36). Mixed- (4Hz and 100Hz) or alternating- (4Hz on 1 day; 100Hz on the next day) frequency TENS at sensory intensity and 100micros pulse duration. Paw and joint withdrawal thresholds to mechanical stimuli were assessed before induction of inflammation, and before and after daily application of TENS. The reduced paw and joint withdrawal thresholds that occur 24 hours after the induction of inflammation were significantly reversed by the first administration of TENS when compared with sham treatment or to the condition before TENS treatment, which was observed through day 9. By the tenth day, repeated daily administration of either mixed- or alternating-frequency TENS did not reverse the decreased paw and joint withdrawal thresholds. These data suggest that repeated administration of modulating frequency TENS leads to a development of opioid tolerance. However, this tolerance effect is delayed by approximately 5 days compared with administration of low- or high-frequency TENS independently. Clinically, we can infer that a treatment schedule of repeated daily TENS administration will result in a tolerance effect. Moreover, modulating low and high frequency TENS seems to produce a better analgesic effect and tolerance is slower to develop.

Introducing an on-line adaptive procedure for prostate image guided intensity modulate proton therapy.

PubMed

Zhang, M; Westerly, D C; Mackie, T R

2011-08-07

With on-line image guidance (IG), prostate shifts relative to the bony anatomy can be corrected by realigning the patient with respect to the treatment fields. In image guided intensity modulated proton therapy (IG-IMPT), because the proton range is more sensitive to the material it travels through, the realignment may introduce large dose variations. This effect is studied in this work and an on-line adaptive procedure is proposed to restore the planned dose to the target. A 2D anthropomorphic phantom was constructed from a real prostate patient's CT image. Two-field laterally opposing spot 3D-modulation and 24-field full arc distal edge tracking (DET) plans were generated with a prescription of 70 Gy to the planning target volume. For the simulated delivery, we considered two types of procedures: the non-adaptive procedure and the on-line adaptive procedure. In the non-adaptive procedure, only patient realignment to match the prostate location in the planning CT was performed. In the on-line adaptive procedure, on top of the patient realignment, the kinetic energy for each individual proton pencil beam was re-determined from the on-line CT image acquired after the realignment and subsequently used for delivery. Dose distributions were re-calculated for individual fractions for different plans and different delivery procedures. The results show, without adaptive, that both the 3D-modulation and the DET plans experienced delivered dose degradation by having large cold or hot spots in the prostate. The DET plan had worse dose degradation than the 3D-modulation plan. The adaptive procedure effectively restored the planned dose distribution in the DET plan, with delivered prostate D(98%), D(50%) and D(2%) values less than 1% from the prescription. In the 3D-modulation plan, in certain cases the adaptive procedure was not effective to reduce the delivered dose degradation and yield similar results as the non-adaptive procedure. In conclusion, based on this 2D phantom study, by updating the proton pencil beam energy from the on-line image after realignment, this on-line adaptive procedure is necessary and effective for the DET-based IG-IMPT. Without dose re-calculation and re-optimization, it could be easily incorporated into the clinical workflow.

Introducing an on-line adaptive procedure for prostate image guided intensity modulate proton therapy

NASA Astrophysics Data System (ADS)

Zhang, M.; Westerly, D. C.; Mackie, T. R.

2011-08-01

With on-line image guidance (IG), prostate shifts relative to the bony anatomy can be corrected by realigning the patient with respect to the treatment fields. In image guided intensity modulated proton therapy (IG-IMPT), because the proton range is more sensitive to the material it travels through, the realignment may introduce large dose variations. This effect is studied in this work and an on-line adaptive procedure is proposed to restore the planned dose to the target. A 2D anthropomorphic phantom was constructed from a real prostate patient's CT image. Two-field laterally opposing spot 3D-modulation and 24-field full arc distal edge tracking (DET) plans were generated with a prescription of 70 Gy to the planning target volume. For the simulated delivery, we considered two types of procedures: the non-adaptive procedure and the on-line adaptive procedure. In the non-adaptive procedure, only patient realignment to match the prostate location in the planning CT was performed. In the on-line adaptive procedure, on top of the patient realignment, the kinetic energy for each individual proton pencil beam was re-determined from the on-line CT image acquired after the realignment and subsequently used for delivery. Dose distributions were re-calculated for individual fractions for different plans and different delivery procedures. The results show, without adaptive, that both the 3D-modulation and the DET plans experienced delivered dose degradation by having large cold or hot spots in the prostate. The DET plan had worse dose degradation than the 3D-modulation plan. The adaptive procedure effectively restored the planned dose distribution in the DET plan, with delivered prostate D98%, D50% and D2% values less than 1% from the prescription. In the 3D-modulation plan, in certain cases the adaptive procedure was not effective to reduce the delivered dose degradation and yield similar results as the non-adaptive procedure. In conclusion, based on this 2D phantom study, by updating the proton pencil beam energy from the on-line image after realignment, this on-line adaptive procedure is necessary and effective for the DET-based IG-IMPT. Without dose re-calculation and re-optimization, it could be easily incorporated into the clinical workflow.

Overall nadir view of ISS seen during flyaround

NASA Image and Video Library

2001-07-22

STS104-332-027 (21 July 2001) --- The International Space Station (ISS), just days after receiving the installment of the Quest airlock, was photographed by one the STS-104 astronauts during a fly-around of the orbital outpost. The survey occurred shortly after Atlantis' undocking. The Canadarm2 or Space Station Remote Manipulator System (SSRMS) appears to be pointed toward the new airlock on the station's starboard side. The STS-104 and Expedition Two crew's joint efforts in the past several days, in which the airlock was installed and other work was accomplished, marked the completion of the second phase of the station. Within the last year (beginning in July of 2000), 77 tons of hardware have been added to the complex, including the Zvezda module, the Z1 Truss Assembly, Pressurized Mating Adapter 3, the P6 Truss and its 240-foot long solar arrays, the U.S. laboratory Destiny, the Canadarm2 and finally the Quest airlock.

Overall nadir view of ISS seen during flyaround

NASA Image and Video Library

2001-07-22

STS104-332-026 (21 July 2001) --- The International Space Station (ISS), just days after receiving the installment of the Quest airlock, was photographed by one the STS-104 astronauts during a fly-around of the orbital outpost. The survey occurred shortly after Atlantis' undocking. The Canadarm2 or Space Station Remote Manipulator System (SSRMS) appears to be pointed toward the new airlock on the station's starboard side. The STS-104 and Expedition Two crew's joint efforts in the past several days, in which the airlock was installed and other work was accomplished, marked the completion of the second phase of the station. Within the last year (beginning in July of 2000), 77 tons of hardware have been added to the complex, including the Zvezda module, the Z1 Truss Assembly, Pressurized Mating Adapter 3, the P6 Truss and its 240-foot long solar arrays, the U.S. laboratory Destiny, the Canadarm2 and finally the Quest airlock.

Safety and licensing of a small modular gas-cooled reactor system

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, N.W.; Kelley, A.P. Jr.

A modular side-by-side high-temperature gas-cooled reactor (SBS-HTGR) is being developed by Interatom/Kraftwerk Union (KWU). The General Electric Company and Interatom/KWU entered into a proprietary working agreement to continue develop jointly of the SBS-HTGR. A study on adapting the SBS-HTGR for application in the US has been completed. The study investigated the safety characteristics and the use of this type of design in an innovative approach to licensing. The safety objective guiding the design of the modular SBS-HTGR is to control radionuclide release by the retention of fission products within the fuel particles with minimal reliance on active design features. Themore » philosophy on which this objective is predicated is that by providing a simple safety case, the safety criteria can be demonstrated as being met with high confidence through conduct of a full-scale module safety test.« less

Integrated High-Speed Torque Control System for a Robotic Joint

NASA Technical Reports Server (NTRS)

Davis, Donald R. (Inventor); Radford, Nicolaus A. (Inventor); Permenter, Frank Noble (Inventor); Valvo, Michael C. (Inventor); Askew, R. Scott (Inventor)

2013-01-01

A control system for achieving high-speed torque for a joint of a robot includes a printed circuit board assembly (PCBA) having a collocated joint processor and high-speed communication bus. The PCBA may also include a power inverter module (PIM) and local sensor conditioning electronics (SCE) for processing sensor data from one or more motor position sensors. Torque control of a motor of the joint is provided via the PCBA as a high-speed torque loop. Each joint processor may be embedded within or collocated with the robotic joint being controlled. Collocation of the joint processor, PIM, and high-speed bus may increase noise immunity of the control system, and the localized processing of sensor data from the joint motor at the joint level may minimize bus cabling to and from each control node. The joint processor may include a field programmable gate array (FPGA).

The Joint Adaptive Kalman Filter (JAKF) for Vehicle Motion State Estimation.

PubMed

Gao, Siwei; Liu, Yanheng; Wang, Jian; Deng, Weiwen; Oh, Heekuck

2016-07-16

This paper proposes a multi-sensory Joint Adaptive Kalman Filter (JAKF) through extending innovation-based adaptive estimation (IAE) to estimate the motion state of the moving vehicles ahead. JAKF views Lidar and Radar data as the source of the local filters, which aims to adaptively adjust the measurement noise variance-covariance (V-C) matrix 'R' and the system noise V-C matrix 'Q'. Then, the global filter uses R to calculate the information allocation factor 'β' for data fusion. Finally, the global filter completes optimal data fusion and feeds back to the local filters to improve the measurement accuracy of the local filters. Extensive simulation and experimental results show that the JAKF has better adaptive ability and fault tolerance. JAKF enables one to bridge the gap of the accuracy difference of various sensors to improve the integral filtering effectivity. If any sensor breaks down, the filtered results of JAKF still can maintain a stable convergence rate. Moreover, the JAKF outperforms the conventional Kalman filter (CKF) and the innovation-based adaptive Kalman filter (IAKF) with respect to the accuracy of displacement, velocity, and acceleration, respectively.

Signaling networks in joint development

PubMed Central

Salva, Joanna E.; Merrill, Amy E.

2016-01-01

Here we review studies identifying regulatory networks responsible for synovial, cartilaginous, and fibrous joint development. Synovial joints, characterized by the fluid-filled synovial space between the bones, are found in high-mobility regions and are the most common type of joint. Cartilaginous joints unite adjacent bones through either a hyaline cartilage or fibrocartilage intermediate. Fibrous joints, which include the cranial sutures, form a direct union between bones through fibrous connective tissue. We describe how the distinct morphologic and histogenic characteristics of these joint classes are established during embryonic development. Collectively, these studies reveal that despite the heterogeneity of joint strength and mobility, joint development throughout the skeleton utilizes common signaling networks via long-range morphogen gradients and direct cell-cell contact. This suggests that different joint types represent specialized variants of homologous developmental modules. Identifying the unifying aspects of the signaling networks between joint classes allows a more complete understanding of the signaling code for joint formation, which is critical to improving strategies for joint regeneration and repair. PMID:27859991

Rate adaptive multilevel coded modulation with high coding gain in intensity modulation direct detection optical communication

NASA Astrophysics Data System (ADS)

Xiao, Fei; Liu, Bo; Zhang, Lijia; Xin, Xiangjun; Zhang, Qi; Tian, Qinghua; Tian, Feng; Wang, Yongjun; Rao, Lan; Ullah, Rahat; Zhao, Feng; Li, Deng'ao

2018-02-01

A rate-adaptive multilevel coded modulation (RA-MLC) scheme based on fixed code length and a corresponding decoding scheme is proposed. RA-MLC scheme combines the multilevel coded and modulation technology with the binary linear block code at the transmitter. Bits division, coding, optional interleaving, and modulation are carried out by the preset rule, then transmitted through standard single mode fiber span equal to 100 km. The receiver improves the accuracy of decoding by means of soft information passing through different layers, which enhances the performance. Simulations are carried out in an intensity modulation-direct detection optical communication system using MATLAB®. Results show that the RA-MLC scheme can achieve bit error rate of 1E-5 when optical signal-to-noise ratio is 20.7 dB. It also reduced the number of decoders by 72% and realized 22 rate adaptation without significantly increasing the computing time. The coding gain is increased by 7.3 dB at BER=1E-3.

Optimum Adaptive Modulation and Channel Coding Scheme for Frequency Domain Channel-Dependent Scheduling in OFDM Based Evolved UTRA Downlink

NASA Astrophysics Data System (ADS)

Miki, Nobuhiko; Kishiyama, Yoshihisa; Higuchi, Kenichi; Sawahashi, Mamoru; Nakagawa, Masao

In the Evolved UTRA (UMTS Terrestrial Radio Access) downlink, Orthogonal Frequency Division Multiplexing (OFDM) based radio access was adopted because of its inherent immunity to multipath interference and flexible accommodation of different spectrum arrangements. This paper presents the optimum adaptive modulation and channel coding (AMC) scheme when resource blocks (RBs) is simultaneously assigned to the same user when frequency and time domain channel-dependent scheduling is assumed in the downlink OFDMA radio access with single-antenna transmission. We start by presenting selection methods for the modulation and coding scheme (MCS) employing mutual information both for RB-common and RB-dependent modulation schemes. Simulation results show that, irrespective of the application of power adaptation to RB-dependent modulation, the improvement in the achievable throughput of the RB-dependent modulation scheme compared to that for the RB-common modulation scheme is slight, i.e., 4 to 5%. In addition, the number of required control signaling bits in the RB-dependent modulation scheme becomes greater than that for the RB-common modulation scheme. Therefore, we conclude that the RB-common modulation and channel coding rate scheme is preferred, when multiple RBs of the same coded stream are assigned to one user in the case of single-antenna transmission.

Lyapunov function-based control laws for revolute robot arms - Tracking control, robustness, and adaptive control

NASA Technical Reports Server (NTRS)

Wen, John T.; Kreutz-Delgado, Kenneth; Bayard, David S.

1992-01-01

A new class of joint level control laws for all-revolute robot arms is introduced. The analysis is similar to a recently proposed energy-like Liapunov function approach, except that the closed-loop potential function is shaped in accordance with the underlying joint space topology. This approach gives way to a much simpler analysis and leads to a new class of control designs which guarantee both global asymptotic stability and local exponential stability. When Coulomb and viscous friction and parameter uncertainty are present as model perturbations, a sliding mode-like modification of the control law results in a robustness-enhancing outer loop. Adaptive control is formulated within the same framework. A linear-in-the-parameters formulation is adopted and globally asymptotically stable adaptive control laws are derived by simply replacing unknown model parameters by their estimates (i.e., certainty equivalence adaptation).

Terrain Adaptability Mechanism of Large Ruminants' Feet on the Kinematics View

PubMed Central

Zhang, Qun; Ding, Xilun; Xu, Kun

2015-01-01

Ruminants live in various parts of land. Similar cloven hooves assist ruminants in adapting to different ground environment during locomotion. This paper analyzes the general terrain adaptability of the feet of ruminants using kinematics of the equivalent mechanism model based on screw theory. Cloven hooves could adjust attitude by changing relative positions between two digits in swing phase. This function helps to choose better landing orientation. “Grasping” or “holding” a rock or other object on the ground passively provides extra adhesion force in stance phase. Ruminants could adjust the position of the metacarpophalangeal joint or metatarsophalangeal joint (MTP or MCP) with no relative motion between the tip of feet and the ground, which ensures the adhesion and dexterity in stance phase. These functions are derived from an example from chamois' feet and several assumptions, which are believed to demonstrate the foundation of adaptation of ruminants and ensure a stable and continuous movement. PMID:27019579

Terrain Adaptability Mechanism of Large Ruminants' Feet on the Kinematics View.

PubMed

Zhang, Qun; Ding, Xilun; Xu, Kun

2015-01-01

Ruminants live in various parts of land. Similar cloven hooves assist ruminants in adapting to different ground environment during locomotion. This paper analyzes the general terrain adaptability of the feet of ruminants using kinematics of the equivalent mechanism model based on screw theory. Cloven hooves could adjust attitude by changing relative positions between two digits in swing phase. This function helps to choose better landing orientation. "Grasping" or "holding" a rock or other object on the ground passively provides extra adhesion force in stance phase. Ruminants could adjust the position of the metacarpophalangeal joint or metatarsophalangeal joint (MTP or MCP) with no relative motion between the tip of feet and the ground, which ensures the adhesion and dexterity in stance phase. These functions are derived from an example from chamois' feet and several assumptions, which are believed to demonstrate the foundation of adaptation of ruminants and ensure a stable and continuous movement.

Astronauts Stafford and Brand at controls of Apollo Command Module

NASA Technical Reports Server (NTRS)

1975-01-01

Two American ASTP crewmen, Astronauts Thomas P. Stafford (foreground) and Vance D. Brand are seen at the controls of the Apollo Command Module during the joint U.S.-USSR Apollo Soyuz Test Project (ASTP) docking in Earth orbit mission.

Behavioral and Neural Adaptation in Approach Behavior.

PubMed

Wang, Shuo; Falvello, Virginia; Porter, Jenny; Said, Christopher P; Todorov, Alexander

2018-06-01

People often make approachability decisions based on perceived facial trustworthiness. However, it remains unclear how people learn trustworthiness from a population of faces and whether this learning influences their approachability decisions. Here we investigated the neural underpinning of approach behavior and tested two important hypotheses: whether the amygdala adapts to different trustworthiness ranges and whether the amygdala is modulated by task instructions and evaluative goals. We showed that participants adapted to the stimulus range of perceived trustworthiness when making approach decisions and that these decisions were further modulated by the social context. The right amygdala showed both linear response and quadratic response to trustworthiness level, as observed in prior studies. Notably, the amygdala's response to trustworthiness was not modulated by stimulus range or social context, a possible neural dynamic adaptation. Together, our data have revealed a robust behavioral adaptation to different trustworthiness ranges as well as a neural substrate underlying approach behavior based on perceived facial trustworthiness.

Joint CPT and N resonance in compact atomic time standards

NASA Astrophysics Data System (ADS)

Crescimanno, Michael; Hohensee, Michael; Xiao, Yanhong; Phillips, David; Walsworth, Ron

2008-05-01

Currently development efforts towards small, low power atomic time standards use current-modulated VCSELs to generate phase-coherent optical sidebands that interrogate the hyperfine structure of alkali atoms such as rubidium. We describe and use a modified four-level quantum optics model to study the optimal operating regime of the joint CPT- and N-resonance clock. Resonant and non-resonant light shifts as well as modulation comb detuning effects play a key role in determining the optimal operating point of such clocks. We further show that our model is in good agreement with experimental tests performed using Rb-87 vapor cells.

Dopamine D1 receptor activation contributes to light-adapted changes in retinal inhibition to rod bipolar cells.

PubMed

Flood, Michael Daniel; Moore-Dotson, Johnnie M; Eggers, Erika D

2018-05-30

Dopamine modulation of retinal signaling has been shown to be an important part of retinal adaptation to increased background light levels but the role of dopamine modulation of retinal inhibition is not clear. We previously showed that light adaptation causes a large reduction in inhibition to rod bipolar cells, potentially to match the decrease in excitation after rod saturation. In this study we determined how dopamine D1 receptors in the inner retina contribute to this modulation. We found that D1 receptor activation significantly decreased the magnitude of inhibitory light responses from rod bipolar cells, while D1 receptor blockade during light adaptation partially prevented this decline. To determine what mechanisms were involved in the modulation of inhibitory light responses, we measured the effect of D1 receptor activation on spontaneous currents and currents evoked from electrically stimulating amacrine cell inputs to rod bipolar cells. D1 receptor activation decreased the frequency of spontaneous inhibition with no change in event amplitudes, suggesting a presynaptic change in amacrine cell activity in agreement with previous reports that rod bipolar cells lack D1 receptors. Additionally, we found that D1 receptor activation reduced the amplitude of electrically-evoked responses, showing that D1 receptors can modulate amacrine cells directly. Our results suggest that D1 receptor activation can replicate a large portion, but not all of the effects of light adaptation, likely by modulating release from amacrine cells onto rod bipolar cells.

How MAP kinase modules function as robust, yet adaptable, circuits.

PubMed

Tian, Tianhai; Harding, Angus

2014-01-01

Genetic and biochemical studies have revealed that the diversity of cell types and developmental patterns evident within the animal kingdom is generated by a handful of conserved, core modules. Core biological modules must be robust, able to maintain functionality despite perturbations, and yet sufficiently adaptable for random mutations to generate phenotypic variation during evolution. Understanding how robust, adaptable modules have influenced the evolution of eukaryotes will inform both evolutionary and synthetic biology. One such system is the MAP kinase module, which consists of a 3-tiered kinase circuit configuration that has been evolutionarily conserved from yeast to man. MAP kinase signal transduction pathways are used across eukaryotic phyla to drive biological functions that are crucial for life. Here we ask the fundamental question, why do MAPK modules follow a conserved 3-tiered topology rather than some other number? Using computational simulations, we identify a fundamental 2-tiered circuit topology that can be readily reconfigured by feedback loops and scaffolds to generate diverse signal outputs. When this 2-kinase circuit is connected to proximal input kinases, a 3-tiered modular configuration is created that is both robust and adaptable, providing a biological circuit that can regulate multiple phenotypes and maintain functionality in an uncertain world. We propose that the 3-tiered signal transduction module has been conserved through positive selection, because it facilitated the generation of phenotypic variation during eukaryotic evolution.

How MAP kinase modules function as robust, yet adaptable, circuits

PubMed Central

Tian, Tianhai; Harding, Angus

2014-01-01

Genetic and biochemical studies have revealed that the diversity of cell types and developmental patterns evident within the animal kingdom is generated by a handful of conserved, core modules. Core biological modules must be robust, able to maintain functionality despite perturbations, and yet sufficiently adaptable for random mutations to generate phenotypic variation during evolution. Understanding how robust, adaptable modules have influenced the evolution of eukaryotes will inform both evolutionary and synthetic biology. One such system is the MAP kinase module, which consists of a 3-tiered kinase circuit configuration that has been evolutionarily conserved from yeast to man. MAP kinase signal transduction pathways are used across eukaryotic phyla to drive biological functions that are crucial for life. Here we ask the fundamental question, why do MAPK modules follow a conserved 3-tiered topology rather than some other number? Using computational simulations, we identify a fundamental 2-tiered circuit topology that can be readily reconfigured by feedback loops and scaffolds to generate diverse signal outputs. When this 2-kinase circuit is connected to proximal input kinases, a 3-tiered modular configuration is created that is both robust and adaptable, providing a biological circuit that can regulate multiple phenotypes and maintain functionality in an uncertain world. We propose that the 3-tiered signal transduction module has been conserved through positive selection, because it facilitated the generation of phenotypic variation during eukaryotic evolution. PMID:25483189

Application of TrackEye in equine locomotion research.

PubMed

Drevemo, S; Roepstorff, L; Kallings, P; Johnston, C J

1993-01-01

TrackEye is an analysis system, which is applicable for equine biokinematic studies. It covers the whole process from digitizing of images, automatic target tracking and analysis. Key components in the system are an image work station for processing of video images and a high-resolution film-to-video scanner for 16-mm film. A recording module controls the input device and handles the capture of image sequences into a videodisc system, and a tracking module is able to follow reference markers automatically. The system offers a flexible analysis including calculations of markers displacements, distances and joint angles, velocities and accelerations. TrackEye was used to study effects of phenylbutazone on the fetlock and carpal joint angle movements in a horse with a mild lameness caused by osteo-arthritis in the fetlock joint of a forelimb. Significant differences, most evident before treatment, were observed in the minimum fetlock and carpal joint angles when contralateral limbs were compared (p < 0.001). The minimum fetlock angle and the minimum carpal joint angle were significantly greater in the lame limb before treatment compared to those 6, 37 and 49 h after the last treatment (p < 0.001).

Exoskeleton control for lower-extremity assistance based on adaptive frequency oscillators: adaptation of muscle activation and movement frequency.

PubMed

Aguirre-Ollinger, Gabriel

2015-01-01

In this article, we analyze a novel strategy for assisting the lower extremities based on adaptive frequency oscillators. Our aim is to use the control algorithm presented here as a building block for the control of powered lower-limb exoskeletons. The algorithm assists cyclic movements of the human extremities by synchronizing actuator torques with the estimated net torque exerted by the muscles. Synchronization is produced by a nonlinear dynamical system combining an adaptive frequency oscillator with a form of adaptive Fourier analysis. The system extracts, in real time, the fundamental frequency component of the net muscle torque acting on a specific joint. Said component, nearly sinusoidal in shape, is the basis for the assistive torque waveform delivered by the exoskeleton. The action of the exoskeleton can be interpreted as a virtual reduction in the mechanical impedance of the leg. We studied the ability of human subjects to adapt their muscle activation to the assistive torque. Ten subjects swung their extended leg while coupled to a stationary hip joint exoskeleton. The experiment yielded a significant decrease, with respect to unassisted movement, of the activation levels of an agonist/antagonist pair of muscles controlling the hip joint's motion, which suggests the exoskeleton control has potential for assisting human gait. A moderate increase in swing frequency was observed as well. We theorize that the increase in frequency can be explained by the impedance model of the assisted leg. Per this model, subjects adjust their swing frequency in order to control the amount of reduction in net muscle torque. © IMechE 2015.

[Tinnitus and temporomandibular joint: State of the art].

PubMed

Lina-Granade, G; Truy, E; Ionescu, E; Garnier, P; Thai Van, H

2016-12-01

Tinnitus has been described in temporomandibular joint dysfunction for a long time. Yet, other disorders, such as hearing loss, stress, anxiety and depression, play a major role in the pathophysiology of tinnitus. Temporomandibular joint dysfunctions seem to increase the risk of tinnitus in patients with other predisposing factors. Especially somatosensory tinnitus, which is characterized by sound modulations with neck or mandible movements, is frequently associated with temporomandibular joint dysfunction, but it is not pathognomonic of such a disorder. In such cases, functional therapy of the temporomandibular joint should be part of the multidisciplinary rehabilitation of patients with tinnitus. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Agonist and antagonist muscle activation in elite athletes: influence of age.

PubMed

Quinzi, Federico; Camomilla, Valentina; Felici, Francesco; Di Mario, Alberto; Sbriccoli, Paola

2015-01-01

Age-related neuromuscular control adaptations have been investigated mainly in untrained populations, where higher antagonist activation in adults was observed with respect to children. In elite athletes age-related differences in neuromuscular control have scarcely been investigated. Therefore, this study aims at investigating differences in co-activation about the knee joint in two groups of karate athletes belonging to the Junior (JK) and Senior (SK) age categories, performing the roundhouse kick (RK). Six SK and six JK performed the RK impacting on a punching bag. Each participant performed three attempts during which kicking limb kinematics and sEMG from the vastus lateralis (VL) and from the biceps femoris (BF) were recorded. Co-activation index during knee flexion and extension (CIF; CIE) and agonist and antagonist activation areas of VL and BF (I AGO-VL; I AGO-BF; I ANT-VL; I ANT-BF) were computed. Hip and knee range of motion, peak angular velocity and minima and maxima of lower limb angular momentum were computed. During knee extension, the SK demonstrated higher CIE, higher IANT-BF and higher total angular momentum with respect to the JK. Significant relationships were observed between I ANT-BF and total angular momentum maxima, and between I ANT-BF and age. IANT-BF is partially related to the age of the group and to joint protection upon impact. Moreover, given the very brief duration of the task, a feed-forward mechanism modulating antagonist activation partly based on the stress imposed on the knee joint could be hypothesized. This mechanism potentially involves skill dependent re-modelling of the peripheral and central nervous system.

Prediction of Tensile Strength of Friction Stir Weld Joints with Adaptive Neuro-Fuzzy Inference System (ANFIS) and Neural Network

NASA Technical Reports Server (NTRS)

Dewan, Mohammad W.; Huggett, Daniel J.; Liao, T. Warren; Wahab, Muhammad A.; Okeil, Ayman M.

2015-01-01

Friction-stir-welding (FSW) is a solid-state joining process where joint properties are dependent on welding process parameters. In the current study three critical process parameters including spindle speed (??), plunge force (????), and welding speed (??) are considered key factors in the determination of ultimate tensile strength (UTS) of welded aluminum alloy joints. A total of 73 weld schedules were welded and tensile properties were subsequently obtained experimentally. It is observed that all three process parameters have direct influence on UTS of the welded joints. Utilizing experimental data, an optimized adaptive neuro-fuzzy inference system (ANFIS) model has been developed to predict UTS of FSW joints. A total of 1200 models were developed by varying the number of membership functions (MFs), type of MFs, and combination of four input variables (??,??,????,??????) utilizing a MATLAB platform. Note EFI denotes an empirical force index derived from the three process parameters. For comparison, optimized artificial neural network (ANN) models were also developed to predict UTS from FSW process parameters. By comparing ANFIS and ANN predicted results, it was found that optimized ANFIS models provide better results than ANN. This newly developed best ANFIS model could be utilized for prediction of UTS of FSW joints.

No evidence hip joint angle modulates intrinsically produced stretch reflex in human hopping.

PubMed

Gibson, W; Campbell, A; Allison, G

2013-09-01

Motor output in activities such as walking and hopping is suggested to be mediated neurally by purported stretch reflex augmentation of muscle output. Reflex EMG activity during these tasks has been frequently investigated in the soleus muscle; with alterations in reflex amplitude being associated with changes in hip joint angle/phase of the gait cycle. Previous work has focussed on reflex activity induced by an artificial perturbation or by induction of H-reflexes. As such, it is currently unknown if stretch reflex activity induced intrinsically (as part of the task) is modulated by changes in hip joint angle. This study investigated whether hip joint angle modulated reflex EMG 'burst' activity during a hopping task performed on a custom-built partially reclined sleigh. Ten subjects participated; EMG and kinematic data (VICON motor capture system) was collected for each hop cycle. Participants completed 5 sets of 30s of self-paced hopping in (1) hip neutral and (2) hip 60° flexion conditions. There was no difference in EMG 'burst' activity or in sagittal plane kinematics (knee/ankle) in the hopping task between the two conditions. The results indicate that during a functional task such as hopping, changes in hip angle do not alter the stretch reflex-like activity associated with landing. Copyright © 2013 Elsevier B.V. All rights reserved.

A New Powered Lower Limb Prosthesis Control Framework Based on Adaptive Dynamic Programming.

PubMed

Wen, Yue; Si, Jennie; Gao, Xiang; Huang, Stephanie; Huang, He Helen

2017-09-01

This brief presents a novel application of adaptive dynamic programming (ADP) for optimal adaptive control of powered lower limb prostheses, a type of wearable robots to assist the motor function of the limb amputees. Current control of these robotic devices typically relies on finite state impedance control (FS-IC), which lacks adaptability to the user's physical condition. As a result, joint impedance settings are often customized manually and heuristically in clinics, which greatly hinder the wide use of these advanced medical devices. This simulation study aimed at demonstrating the feasibility of ADP for automatic tuning of the twelve knee joint impedance parameters during a complete gait cycle to achieve balanced walking. Given that the accurate models of human walking dynamics are difficult to obtain, the model-free ADP control algorithms were considered. First, direct heuristic dynamic programming (dHDP) was applied to the control problem, and its performance was evaluated on OpenSim, an often-used dynamic walking simulator. For the comparison purposes, we selected another established ADP algorithm, the neural fitted Q with continuous action (NFQCA). In both cases, the ADP controllers learned to control the right knee joint and achieved balanced walking, but dHDP outperformed NFQCA in this application during a 200 gait cycle-based testing.

Reward Modulates Adaptations to Conflict

ERIC Educational Resources Information Center

Braem, Senne; Verguts, Tom; Roggeman, Chantal; Notebaert, Wim

2012-01-01

Both cognitive conflict (e.g. Verguts & Notebaert, 2009) and reward signals (e.g. Waszak & Pholulamdeth, 2009) have been proposed to enhance task-relevant associations. Bringing these two notions together, we predicted that reward modulates conflict-based sequential adaptations in cognitive control. This was tested combining either a single…

LUNAR MODULE TEST ARTICLE [LTA] [2R] IS MOVED FOR MATING TO LUNAR MODULE ADAPTER

NASA Technical Reports Server (NTRS)

1967-01-01

The Lunar Module Test Article [LTA] 2R, for the second Saturn V mission, is being moved from the low bay of the Manned Spacecraft Operations Building for mating with the spacecraft Lunar Module Adapter. The second Saturn V [502], except for a different lunar return trajectory, will be a repeat of the Apollo 4 unmanned Earth orbital flight of a high apogee for systems testing using several propulsion system burns and a heat shield test at lunar re-entry speed.

Amplitude modulation reduces loudness adaptation to high-frequency tones.

PubMed

Wynne, Dwight P; George, Sahara E; Zeng, Fan-Gang

2015-07-01

Long-term loudness perception of a sound has been presumed to depend on the spatial distribution of activated auditory nerve fibers as well as their temporal firing pattern. The relative contributions of those two factors were investigated by measuring loudness adaptation to sinusoidally amplitude-modulated 12-kHz tones. The tones had a total duration of 180 s and were either unmodulated or 100%-modulated at one of three frequencies (4, 20, or 100 Hz), and additionally varied in modulation depth from 0% to 100% at the 4-Hz frequency only. Every 30 s, normal-hearing subjects estimated the loudness of one of the stimuli played at 15 dB above threshold in random order. Without any amplitude modulation, the loudness of the unmodulated tone after 180 s was only 20% of the loudness at the onset of the stimulus. Amplitude modulation systematically reduced the amount of loudness adaptation, with the 100%-modulated stimuli, regardless of modulation frequency, maintaining on average 55%-80% of the loudness at onset after 180 s. Because the present low-frequency amplitude modulation produced minimal changes in long-term spectral cues affecting the spatial distribution of excitation produced by a 12-kHz pure tone, the present result indicates that neural synchronization is critical to maintaining loudness perception over time.

Probability differently modulating the effects of reward and punishment on visuomotor adaptation.

PubMed

Song, Yanlong; Smiley-Oyen, Ann L

2017-12-01

Recent human motor learning studies revealed that punishment seemingly accelerated motor learning but reward enhanced consolidation of motor memory. It is not evident how intrinsic properties of reward and punishment modulate the potentially dissociable effects of reward and punishment on motor learning and motor memory. It is also not clear what causes the dissociation of the effects of reward and punishment. By manipulating probability of distribution, a critical property of reward and punishment, the present study demonstrated that probability had distinct modulation on the effects of reward and punishment in adapting to a sudden visual rotation and consolidation of the adaptation memory. Specifically, two probabilities of monetary reward and punishment distribution, 50 and 100%, were applied during young adult participants adapting to a sudden visual rotation. Punishment and reward showed distinct effects on motor adaptation and motor memory. The group that received punishments in 100% of the adaptation trials adapted significantly faster than the other three groups, but the group that received rewards in 100% of the adaptation trials showed marked savings in re-adapting to the same rotation. In addition, the group that received punishments in 50% of the adaptation trials that were randomly selected also had savings in re-adapting to the same rotation. Sensitivity to sensory prediction error or difference in explicit process induced by reward and punishment may likely contribute to the distinct effects of reward and punishment.

Behavior of stress generated in semiconductor chips with high-temperature joints: Influence of mechanical properties of joint materials

NASA Astrophysics Data System (ADS)

Ito, H.; Kuwahara, M.; Ohta, R.; Usui, M.

2018-04-01

High-temperature joint materials are indispensable to realizing next-generation power modules with high-output performance. However, crack initiation resulting from stress concentration in semiconductor chips joined with high-temperature joint materials remains a critical problem in high-temperature operation. Therefore, clarifying the quantitative influence of joint materials on the stress generated in chips is essential. This study investigates the stress behavior of chips joined by Ni-Sn solid-liquid interdiffusion (SLID), which results in a high-temperature joint material likely to generate cracks after joining or when under thermal cycling. The results are compared with those fabricated using three types of solders, Pb-10%Sn, Sn-0.7%Cu, and Sn-10%Sb (mass %), which are conventional joint materials with different melting points and mechanical properties. Using Ni-Sn SLID results in the generation of high compressive stress (500 MPa) without stress relaxation after the joining process in contrast to the case of solders in which the compressive stresses are low (<300 MPa) and decrease to still lower levels (<250 MPa). In addition, no stress relaxation occurs during thermal cycling when using Ni-Sn SLID, whereas stress relaxation is clearly observed during heating to 200 °C using solders. Different stress behaviors between Ni-Sn SLID and other joint materials are illustrated by their mechanical strength and resistance against plastic and creep deformation. These results suggest that stress relaxation in a chip is key in suppressing crack initiation in highly reliable modules during high-temperature operation.

Inverter power module with distributed support for direct substrate cooling

DOEpatents

Miller, David Harold [San Pedro, CA; Korich, Mark D [Chino Hills, CA; Ward, Terence G [Redondo Beach, CA; Mann, Brooks S [Redondo Beach, CA

2012-08-21

Systems and/or methods are provided for an inverter power module with distributed support for direct substrate cooling. An inverter module comprises a power electronic substrate. A first support frame is adapted to house the power electronic substrate and has a first region adapted to allow direct cooling of the power electronic substrate. A gasket is interposed between the power electronic substrate and the first support frame. The gasket is configured to provide a seal between the first region and the power electronic substrate. A second support frame is adapted to house the power electronic substrate and joined to the first support frame to form the seal.

Feedback and feedforward locomotor adaptations to ankle-foot load in people with incomplete spinal cord injury.

PubMed

Gordon, Keith E; Wu, Ming; Kahn, Jennifer H; Schmit, Brian D

2010-09-01

Humans with spinal cord injury (SCI) modulate locomotor output in response to limb load. Understanding the neural control mechanisms responsible for locomotor adaptation could provide a framework for selecting effective interventions. We quantified feedback and feedforward locomotor adaptations to limb load modulations in people with incomplete SCI. While subjects airstepped (stepping performed with kinematic assistance and 100% bodyweight support), a powered-orthosis created a dorisflexor torque during the "stance phase" of select steps producing highly controlled ankle-load perturbations. When given repetitive, stance phase ankle-load, the increase in hip extension work, 0.27 J/kg above baseline (no ankle-load airstepping), was greater than the response to ankle-load applied during a single step, 0.14 J/kg (P = 0.029). This finding suggests that, at the hip, subjects produced both feedforward and feedback locomotor modulations. We estimate that, at the hip, the locomotor response to repetitive ankle-load was modulated almost equally by ongoing feedback and feedforward adaptations. The majority of subjects also showed after-effects in hip kinetic patterns that lasted 3 min in response to repetitive loading, providing additional evidence of feedforward locomotor adaptations. The magnitude of the after-effect was proportional to the response to repetitive ankle-foot load (R(2) = 0.92). In contrast, increases in soleus EMG amplitude were not different during repetitive and single-step ankle-load exposure, suggesting that ankle locomotor modulations were predominately feedback-based. Although subjects made both feedback and feedforward locomotor adaptations to changes in ankle-load, between-subject variations suggest that walking function may be related to the ability to make feedforward adaptations.

Modulation Between High- and Low-Frequency Transcutaneous Electric Nerve Stimulation Delays the Development of Analgesic Tolerance in Arthritic Rats

PubMed Central

DeSantana, Josimari M.; Santana-Filho, Valter J.; Sluka, Kathleen A.

2009-01-01

Objective To investigate whether repeated administration of modulating frequency transcutaneous electric nerve stimulation (TENS) prevents development of analgesic tolerance. Design Knee joint inflammation (3% carrageenan and kaolin) was induced in rats. Either mixed or alternating frequency was administered daily (20min) for 2 weeks to the inflamed knee under light halothane anesthesia (1%–2%). Setting Laboratory. Animals Adult male Sprague-Dawley rats (N=36). Intervention Mixed- (4Hz and 100Hz) or alternating- (4Hz on 1 day; 100Hz on the next day) frequency TENS at sensory intensity and 100μs pulse duration. Main Outcome Measures Paw and joint withdrawal thresholds to mechanical stimuli were assessed before induction of inflammation, and before and after daily application of TENS. Results The reduced paw and joint withdrawal thresholds that occur 24 hours after the induction of inflammation were significantly reversed by the first administration of TENS when compared with sham treatment or to the condition before TENS treatment, which was observed through day 9. By the tenth day, repeated daily administration of either mixed- or alternating-frequency TENS did not reverse the decreased paw and joint withdrawal thresholds. Conclusions These data suggest that repeated administration of modulating frequency TENS leads to a development of opioid tolerance. However, this tolerance effect is delayed by approximately 5 days compared with administration of low- or high-frequency TENS independently. Clinically, we can infer that a treatment schedule of repeated daily TENS administration will result in a tolerance effect. Moreover, modulating low and high frequency TENS seems to produce a better analgesic effect and tolerance is slower to develop. PMID:18374009

When a Social Experimenter Overwrites Effects of Salient Objects in an Individual Go/No-Go Simon Task - An ERP Study.

PubMed

Michel, René; Bölte, Jens; Liepelt, Roman

2018-01-01

When two persons share a Simon task, a joint Simon effect occurs. The task co-representation account assumes that the joint Simon effect is the product of a vicarious representation of the co-actor's task. In contrast, recent studies show that even (non-human) event-producing objects could elicit a Simon effect in an individual go/no-go Simon task arguing in favor of the referential coding account. For the human-induced Simon effect, a modulation of the P300 component in Electroencephalography (EEG) is typically considered as a neural indicator of the joint Simon effect and task co-representation. Showing that the object-induced Simon effects also modulates the P300 would lead to a re-evaluation of the interpretation of the P300 in individual go/no-go and joint Simon task contexts. To do so, the present study conceptually replicated Experiment 1 from Dolk et al. (2013a) adding EEG recordings and an experimenter controlling the EEG computer to test whether a modulation of the P300 can also be elicited by adding a Japanese waving cat to the task context. Subjects performed an individual go/no-go Simon task with or without a cat placed next to them. Results show an overall Simon effect regardless of the cat's presence and no modulatory influence of the cat on the P300 (Experiment 1), even when conceivably interfering context factors are diminished (Experiment 2). These findings may suggest that the presence of a spatially aligned experimenter in the laboratory may produce an overall Simon effect overwriting a possible modulation of the Japanese waving cat.

Neuromuscular adaptations associated with knee joint angle-specific force change.

PubMed

Noorkõiv, Marika; Nosaka, Kazunori; Blazevich, Anthony J

2014-08-01

Neuromuscular adaptations to joint angle-specific force increases after isometric training have not yet been fully elucidated. This study examined angle-specific neuromuscular adaptations in response to isometric knee extension training at short (SL, joint angle 38.1° ± 3.7°) versus long (LL, 87.5° ± 6.0°) muscle lengths. Sixteen men trained three times a week for 6 wk either at SL (n = 8) or LL (n = 8). Voluntary maximal isometric knee extensor (MVC) force, doublet twitch force, EMG amplitudes (EMG/Mmax), and voluntary activation during MVC force (VA%) were measured at eight knee joint angles (30°-100°) at weeks 0, 3, and 6. Muscle volume and cross-sectional area (CSA) were measured from magnetic resonance imaging scans, and fascicle length (Lf) was assessed using ultrasonography before and after training. Clear joint angle specificity of force increase was seen in SL but not in LL. The 13.4% ± 9.7% (P = 0.01) force increase around the training angle in SL was related to changes in vastus lateralis and vastus medialis EMG/Mmax around the training angle (r = 0.84-0.88, P < 0.05), without changes in the doublet twitch force-angle relation or muscle size. In LL, muscle volume and CSA increased and the changes in CSA at specific muscle regions were correlated with changes in MVC force. A 5.4% ± 4.9% (P = 0.001) increase in Lf found in both groups was not associated with angle-specific force changes. There were no angle-specific changes in VA%. The EMG/Mmax, although not VA%, results suggest that neural adaptations underpinned training-related changes at short quadriceps lengths, but hypertrophic changes predominated after training at long lengths. The findings of this study should contribute to the development of more effective and evidence-based rehabilitation and strength training protocols.

Prolonged stretching of the ankle plantarflexors elicits muscle-tendon adaptations relevant to ankle gait kinetics in children with spastic cerebral palsy.

PubMed

Martín Lorenzo, Teresa; Rocon, Eduardo; Martínez Caballero, Ignacio; Ramírez Barragán, Ana; Lerma Lara, Sergio

2017-11-01

Tissue related ankle hyper-resistance has been reported to contribute to equinus gait in children with spastic cerebral palsy. Hence, ankle plantarflexor stretching programs have been developed in order to restore passive ankle dorsiflexion. Despite high quality evidence on the limited effects of stretching on passive joint mobility, further muscle-tendon adaptations have been reported which may impact gait performance. As such, children with spastic cerebral palsy subject to long-term manual static stretching achieved dorsiflexion gains through the reduction of muscle and fascicle strain whilst preserving tendon strain, and prolonged use of ankle-foot orthoses achieved similar dorsiflexion gains through increased tendon strain whilst preserving muscle and fascicle strain. The latter concurred with normalization of early stance plantarflexor moment yet reductions in push-off plantarflexor moment given the increase in tendon compliance. Therefore, similar limited gains in passive ankle joint mobility in response to stretching may be achieved either by preserving/restoring optimal muscle-tendon function, or at the expense of muscle-tendon function and thus contributing gait impairments. The largest increase in ankle passive joint mobility in children with SCP has been obtained through prolonged plantarflexor stretching through ankle casting combined with botulinum neurotoxin type A. However, to our knowledge, there are no published studies on muscle-tendinous adaptations to ankle casting combined with botulinum toxin type A and its effect on ankle joint gait kinetics. Therefore, we hypothesized that ankle casting elicits muscle-tendon adaptations which concur with altered ankle joint kinetics during the stance phase of gait in children with SCP. More information is needed about the relationships between muscle structure and function, and the effect of specific interventions designed to alter muscle properties and associated functional outcomes in children with spastic cerebral palsy. Copyright © 2017 Elsevier Ltd. All rights reserved.

Modulation-Frequency-Specific Adaptation in Awake Auditory Cortex

PubMed Central

Beitel, Ralph E.; Vollmer, Maike; Heiser, Marc A.; Schreiner, Christoph E.

2015-01-01

Amplitude modulations are fundamental features of natural signals, including human speech and nonhuman primate vocalizations. Because natural signals frequently occur in the context of other competing signals, we used a forward-masking paradigm to investigate how the modulation context of a prior signal affects cortical responses to subsequent modulated sounds. Psychophysical “modulation masking,” in which the presentation of a modulated “masker” signal elevates the threshold for detecting the modulation of a subsequent stimulus, has been interpreted as evidence of a central modulation filterbank and modeled accordingly. Whether cortical modulation tuning is compatible with such models remains unknown. By recording responses to pairs of sinusoidally amplitude modulated (SAM) tones in the auditory cortex of awake squirrel monkeys, we show that the prior presentation of the SAM masker elicited persistent and tuned suppression of the firing rate to subsequent SAM signals. Population averages of these effects are compatible with adaptation in broadly tuned modulation channels. In contrast, modulation context had little effect on the synchrony of the cortical representation of the second SAM stimuli and the tuning of such effects did not match that observed for firing rate. Our results suggest that, although the temporal representation of modulated signals is more robust to changes in stimulus context than representations based on average firing rate, this representation is not fully exploited and psychophysical modulation masking more closely mirrors physiological rate suppression and that rate tuning for a given stimulus feature in a given neuron's signal pathway appears sufficient to engender context-sensitive cortical adaptation. PMID:25878263

Somatosensory tinnitus: Current evidence and future perspectives

PubMed Central

Ralli, Massimo; Greco, Antonio; Turchetta, Rosaria; Altissimi, Giancarlo; de Vincentiis, Marco; Cianfrone, Giancarlo

2017-01-01

In some individuals, tinnitus can be modulated by specific maneuvers of the temporomandibular joint, head and neck, eyes, and limbs. Neuroplasticity seems to play a central role in this capacity for modulation, suggesting that abnormal interactions between the sensory modalities, sensorimotor systems, and neurocognitive and neuroemotional networks may contribute to the development of somatosensory tinnitus. Current evidence supports a link between somatic disorders and higher modulation of tinnitus, especially in patients with a normal hearing threshold. Patients with tinnitus who have somatic disorders seems to have a higher chance of modulating their tinnitus with somatic maneuvers; consistent improvements in tinnitus symptoms have been observed in patients with temporomandibular joint disease following targeted therapy for temporomandibular disorders. Somatosensory tinnitus is often overlooked by otolaryngologists and not fully investigated during the diagnostic process. Somatic disorders, when identified and treated, can be a valid therapeutic target for tinnitus; however, somatic screening of subjects for somatosensory tinnitus is imperative for correct selection of patients who would benefit from a multidisciplinary somatic approach. PMID:28553764

Somatosensory tinnitus: Current evidence and future perspectives.

PubMed

Ralli, Massimo; Greco, Antonio; Turchetta, Rosaria; Altissimi, Giancarlo; de Vincentiis, Marco; Cianfrone, Giancarlo

2017-06-01

In some individuals, tinnitus can be modulated by specific maneuvers of the temporomandibular joint, head and neck, eyes, and limbs. Neuroplasticity seems to play a central role in this capacity for modulation, suggesting that abnormal interactions between the sensory modalities, sensorimotor systems, and neurocognitive and neuroemotional networks may contribute to the development of somatosensory tinnitus. Current evidence supports a link between somatic disorders and higher modulation of tinnitus, especially in patients with a normal hearing threshold. Patients with tinnitus who have somatic disorders seems to have a higher chance of modulating their tinnitus with somatic maneuvers; consistent improvements in tinnitus symptoms have been observed in patients with temporomandibular joint disease following targeted therapy for temporomandibular disorders. Somatosensory tinnitus is often overlooked by otolaryngologists and not fully investigated during the diagnostic process. Somatic disorders, when identified and treated, can be a valid therapeutic target for tinnitus; however, somatic screening of subjects for somatosensory tinnitus is imperative for correct selection of patients who would benefit from a multidisciplinary somatic approach.

Volition-adaptive control for gait training using wearable exoskeleton: preliminary tests with incomplete spinal cord injury individuals.

PubMed

Rajasekaran, Vijaykumar; López-Larraz, Eduardo; Trincado-Alonso, Fernando; Aranda, Joan; Montesano, Luis; Del-Ama, Antonio J; Pons, Jose L

2018-01-03

Gait training for individuals with neurological disorders is challenging in providing the suitable assistance and more adaptive behaviour towards user needs. The user specific adaptation can be defined based on the user interaction with the orthosis and by monitoring the user intentions. In this paper, an adaptive control model, commanded by the user intention, is evaluated using a lower limb exoskeleton with incomplete spinal cord injury individuals (SCI). A user intention based adaptive control model has been developed and evaluated with 4 incomplete SCI individuals across 3 sessions of training per individual. The adaptive control model modifies the joint impedance properties of the exoskeleton as a function of the human-orthosis interaction torques and the joint trajectory evolution along the gait sequence, in real time. The volitional input of the user is identified by monitoring the neural signals, pertaining to the user's motor activity. These volitional inputs are used as a trigger to initiate the gait movement, allowing the user to control the initialization of the exoskeleton movement, independently. A Finite-state machine based control model is used in this set-up which helps in combining the volitional orders with the gait adaptation. The exoskeleton demonstrated an adaptive assistance depending on the patients' performance without guiding them to follow an imposed trajectory. The exoskeleton initiated the trajectory based on the user intention command received from the brain machine interface, demonstrating it as a reliable trigger. The exoskeleton maintained the equilibrium by providing suitable assistance throughout the experiments. A progressive change in the maximum flexion of the knee joint was observed at the end of each session which shows improvement in the patient performance. Results of the adaptive impedance were evaluated by comparing with the application of a constant impedance value. Participants reported that the movement of the exoskeleton was flexible and the walking patterns were similar to their own distinct patterns. This study demonstrates that user specific adaptive control can be applied on a wearable robot based on the human-orthosis interaction torques and modifying the joints' impedance properties. The patients perceived no external or impulsive force and felt comfortable with the assistance provided by the exoskeleton. The main goal of such a user dependent control is to assist the patients' needs and adapt to their characteristics, thus maximizing their engagement in the therapy and avoiding slacking. In addition, the initiation directly controlled by the brain allows synchronizing the user's intention with the afferent stimulus provided by the movement of the exoskeleton, which maximizes the potentiality of the system in neuro-rehabilitative therapies.

Space Shuttle Atlantis is on Launch Pad 39B

NASA Technical Reports Server (NTRS)

2001-01-01

KENNEDY SPACE CENTER, Fla. -- Atop the mobile launcher platform, Space Shuttle Atlantis sits on Launch Pad 39B after rollout from the Vehicle Assembly Building. Seen on either side of the orbiters tail are the tail service masts. They support the fluid, gas and electrical requirements of the orbiters liquid oxygen and liquid hydrogen aft umbilicals. To the left of the orbiter is the white environmental chamber (white room) that mates with the orbiter and holds six persons. It provides access to the orbiter crew compartment. In the background is the Atlantic Ocean. The Shuttle is targeted for launch no earlier than July 12 on mission STS-104, the 10th flight to the International Space Station. The payload on the 11-day mission is the Joint Airlock Module, which will allow astronauts and cosmonauts in residence on the Station to perform future spacewalks without the presence of a Space Shuttle. The module, which comprises a crew lock and an equipment lock, will be connected to the starboard (right) side of Node 1 Unity. Atlantis will also carry oxygen and nitrogen storage tanks, vital to operation of the Joint Airlock, on a Spacelab Logistics Double Pallet in the payload bay. The tanks, to be installed on the perimeter of the Joint Module during the missions spacewalks, will support future spacewalk operations and experiments plus augment the resupply system for the Stations Service Module.

Operation Joint Guard (SFOR) Bosnia. Assessment of Operational Stress and Adaptive Coping Mechanisms of Soldiers

DTIC Science & Technology

1998-03-01

married, 3 children, \\ more than two years w/company J V ^ I am constantly placed in an ethical dilemmas daily in front of my soldiers. I do...and lessons learned are presented . 14. SUBJECT TERMS Bosnia, Operation Joint Guard, Operation Joint Endeavor, Peacekeeping, Stress, Psychological...keeping operations present challenging environments to any military organization and its soldiers. Soldiers will often be required to perform their

Modulation of experimental arthritis by vagal sensory and central brain stimulation.

PubMed

Bassi, Gabriel Shimizu; Dias, Daniel Penteado Martins; Franchin, Marcelo; Talbot, Jhimmy; Reis, Daniel Gustavo; Menezes, Gustavo Batista; Castania, Jaci Airton; Garcia-Cairasco, Norberto; Resstel, Leonardo Barbosa Moraes; Salgado, Helio Cesar; Cunha, Fernando Queiróz; Cunha, Thiago Mattar; Ulloa, Luis; Kanashiro, Alexandre

2017-08-01

Articular inflammation is a major clinical burden in multiple inflammatory diseases, especially in rheumatoid arthritis. Biological anti-rheumatic drug therapies are expensive and increase the risk of systemic immunosuppression, infections, and malignancies. Here, we report that vagus nerve stimulation controls arthritic joint inflammation by inducing local regulation of innate immune response. Most of the previous studies of neuromodulation focused on vagal regulation of inflammation via the efferent peripheral pathway toward the viscera. Here, we report that vagal stimulation modulates arthritic joint inflammation through a novel "afferent" pathway mediated by the locus coeruleus (LC) of the central nervous system. Afferent vagal stimulation activates two sympatho-excitatory brain areas: the paraventricular hypothalamic nucleus (PVN) and the LC. The integrity of the LC, but not that of the PVN, is critical for vagal control of arthritic joint inflammation. Afferent vagal stimulation suppresses articular inflammation in the ipsilateral, but not in the contralateral knee to the hemispheric LC lesion. Central stimulation is followed by subsequent activation of joint sympathetic nerve terminals inducing articular norepinephrine release. Selective adrenergic beta-blockers prevent the effects of articular norepinephrine and thereby abrogate vagal control of arthritic joint inflammation. These results reveals a novel neuro-immune brain map with afferent vagal signals controlling side-specific articular inflammation through specific inflammatory-processing brain centers and joint sympathetic innervations. Copyright © 2017 Elsevier Inc. All rights reserved.

Decentralized adaptive control

NASA Technical Reports Server (NTRS)

Oh, B. J.; Jamshidi, M.; Seraji, H.

1988-01-01

A decentralized adaptive control is proposed to stabilize and track the nonlinear, interconnected subsystems with unknown parameters. The adaptation of the controller gain is derived by using model reference adaptive control theory based on Lyapunov's direct method. The adaptive gains consist of sigma, proportional, and integral combination of the measured and reference values of the corresponding subsystem. The proposed control is applied to the joint control of a two-link robot manipulator, and the performance in computer simulation corresponds with what is expected in theoretical development.

Robotic-Movement Payload Lifter and Manipulator

NASA Technical Reports Server (NTRS)

Doggett, William R. (Inventor); King, Bruce D. (Inventor); Collins, Timothy J. (Inventor); Dorsey, John T. (Inventor)

2011-01-01

A payload lifter/manipulator module includes a rotatable joint supporting spreader arms angularly spaced with respect to one another. A rigid arm is fixedly coupled to the joint and extends out therefrom to a tip. A tension arm has a first end and a second end with the first end being fixedly coupled to the tip of the rigid arm. The tension arm incorporates pivots along the length thereof. Each pivot can be engaged by or disengaged from the outboard end of a spreader arm based on a position of the spreader arm. A hoist, positioned remotely with respect to the module and coupled to the second end of the tension arm, controls the position of the spreader arms to thereby control the position of the rigid arm's tip. Payload lifter/manipulator assemblies can be constructed with one or more of the modules.

Metal to ceramic sealed joint

DOEpatents

Lasecki, J.V.; Novak, R.F.; McBride, J.R.

1991-08-27

A metal to ceramic sealed joint which can withstand wide variations in temperature and maintain a good seal is provided for use in a device adapted to withstand thermal cycling from about 20 to about 1000 degrees C. The sealed joint includes a metal member, a ceramic member having an end portion, and an active metal braze forming a joint to seal the metal member to the ceramic member. The joint is positioned remote from the end portion of the ceramic member to avoid stresses at the ends or edges of the ceramic member. The sealed joint is particularly suited for use to form sealed metal to ceramic joints in a thermoelectric generator such as a sodium heat engine where a solid ceramic electrolyte is joined to metal parts in the system. 11 figures.

Metal to ceramic sealed joint

DOEpatents

Lasecki, John V.; Novak, Robert F.; McBride, James R.

1991-01-01

A metal to ceramic sealed joint which can withstand wide variations in temperature and maintain a good seal is provided for use in a device adapted to withstand thermal cycling from about 20 to about 1000 degrees C. The sealed joint includes a metal member, a ceramic member having an end portion, and an active metal braze forming a joint to seal the metal member to the ceramic member. The joint is positioned remote from the end portion of the ceramic member to avoid stresses at the ends or edges of the ceramic member. The sealed joint is particularly suited for use to form sealed metal to ceramic joints in a thermoelectric generator such as a sodium heat engine where a solid ceramic electrolyte is joined to metal parts in the system.

Adaptive control of a Stewart platform-based manipulator

NASA Technical Reports Server (NTRS)

Nguyen, Charles C.; Antrazi, Sami S.; Zhou, Zhen-Lei; Campbell, Charles E., Jr.

1993-01-01

A joint-space adaptive control scheme for controlling noncompliant motion of a Stewart platform-based manipulator (SPBM) was implemented in the Hardware Real-Time Emulator at Goddard Space Flight Center. The six-degrees of freedom SPBM uses two platforms and six linear actuators driven by dc motors. The adaptive control scheme is based on proportional-derivative controllers whose gains are adjusted by an adaptation law based on model reference adaptive control and Liapunov direct method. It is concluded that the adaptive control scheme provides superior tracking capability as compared to fixed-gain controllers.

Effects of ankle joint position and submaximal muscle contraction intensity on soleus H-reflex modulation in young and older adults.

PubMed

Chen, Yung-Sheng; Zhou, Shi; Cartwright, Colleen

2014-04-01

This study investigated the effects of ankle joint position and submaximal contraction intensity on soleus (SOL) H-reflex modulation. Twenty young (25.1 ± 4.8 years) and 20 older adults (74.2 ± 5.1 years) performed plantar flexions during 10%, 30% and 50% maximal voluntary contractions (MVC) and at ankle positions of neutral (0°), plantar flexion (20°) and dorsiflexion (-20°) in a sitting position. The SOL H-reflex gain in older adults was relatively lower than that in young adults during 10%, 30% and 50% MVC. The SOL H-reflex gain was significantly affected by the intensity of plantar flexion in the respective ankle joint position in both age groups. The latency of H-reflex was prolonged in older adults and was ankle joint dependent in young adults. Young adults demonstrated a shorter duration of the H-reflex response than that of older adults. The results indicated that there were age-related changes in the SOL H-reflex during the ankle plantar flexors activities.

Phase Adaptation and Correction by Adaptive Optics

NASA Astrophysics Data System (ADS)

Tiziani, Hans J.

2010-04-01

Adaptive optical elements and systems for imaging or laser beam propagation are used for some time in particular in astronomy, where the image quality is degraded by atmospheric turbulence. In astronomical telescopes a deformable mirror is frequently used to compensate wavefront-errors due to deformations of the large mirror, vibrations as well as turbulence and hence to increase the image quality. In the last few years interesting elements like Spatial Light Modulators, SLM's, such as photorefractive crystals, liquid crystals and micro mirrors and membrane mirrors were introduced. The development of liquid crystals and micro mirrors was driven by data projectors as consumer products. They contain typically a matrix of individually addressable pixels of liquid crystals and flip mirrors respectively or more recently piston mirrors for special applications. Pixel sizes are in the order of a few microns and therefore also appropriate as active diffractive elements in digital holography or miniature masks. Although liquid crystals are mainly optimized for intensity modulation; they can be used for phase modulation. Adaptive optics is a technology for beam shaping and wavefront adaptation. The application of spatial light modulators for wavefront adaptation and correction and defect analysis as well as sensing will be discussed. Dynamic digital holograms are generated with liquid crystal devices (LCD) and used for wavefront correction as well as for beam shaping and phase manipulation, for instance. Furthermore, adaptive optics is very useful to extend the measuring range of wavefront sensors and for the wavefront adaptation in order to measure and compare the shape of high precision aspherical surfaces.

GRC-2008-C-00349

NASA Image and Video Library

2004-02-26

Code R and Code D hosted NESC Principal Engineer Mike Kirsch who is Program Leader for Composite Crew Module (CCM). The purpose of the visit was to review/observe experiments that GRC is performing in support of the CCM program. The test object is the critical Low Impact Docking System/Tunnel interface joint that links the metal docking ring with the polymer composite tunnel element of the crew module pressure vessel. The rectangular specimens simulated the splice joint between the aluminum and the PMC sheets, including a PMC doubler sheet. GRC was selected for these tests due to our expertise in composite testing and our ability to perform 3D fullfield displacement and strain measurements of the complex bond geometry using digital image correlation. The specimens performed above their minimum load requirements and the full field strain measurements showed the strain levels at the critical bond line. This work is part of a joint Code D & R investigation.

Method and System for Controlling a Dexterous Robot Execution Sequence Using State Classification

NASA Technical Reports Server (NTRS)

Sanders, Adam M. (Inventor); Quillin, Nathaniel (Inventor); Platt, Robert J., Jr. (Inventor); Pfeiffer, Joseph (Inventor); Permenter, Frank Noble (Inventor)

2014-01-01

A robotic system includes a dexterous robot and a controller. The robot includes a plurality of robotic joints, actuators for moving the joints, and sensors for measuring a characteristic of the joints, and for transmitting the characteristics as sensor signals. The controller receives the sensor signals, and is configured for executing instructions from memory, classifying the sensor signals into distinct classes via the state classification module, monitoring a system state of the robot using the classes, and controlling the robot in the execution of alternative work tasks based on the system state. A method for controlling the robot in the above system includes receiving the signals via the controller, classifying the signals using the state classification module, monitoring the present system state of the robot using the classes, and controlling the robot in the execution of alternative work tasks based on the present system state.

Time Reversal Acoustic Communication Using Filtered Multitone Modulation

PubMed Central

Sun, Lin; Chen, Baowei; Li, Haisen; Zhou, Tian; Li, Ruo

2015-01-01

The multipath spread in underwater acoustic channels is severe and, therefore, when the symbol rate of the time reversal (TR) acoustic communication using single-carrier (SC) modulation is high, the large intersymbol interference (ISI) span caused by multipath reduces the performance of the TR process and needs to be removed using the long adaptive equalizer as the post-processor. In this paper, a TR acoustic communication method using filtered multitone (FMT) modulation is proposed in order to reduce the residual ISI in the processed signal using TR. In the proposed method, FMT modulation is exploited to modulate information symbols onto separate subcarriers with high spectral containment and TR technique, as well as adaptive equalization is adopted at the receiver to suppress ISI and noise. The performance of the proposed method is assessed through simulation and real data from a trial in an experimental pool. The proposed method was compared with the TR acoustic communication using SC modulation with the same spectral efficiency. Results demonstrate that the proposed method can improve the performance of the TR process and reduce the computational complexity of adaptive equalization for post-process. PMID:26393586

Time Reversal Acoustic Communication Using Filtered Multitone Modulation.

PubMed

Sun, Lin; Chen, Baowei; Li, Haisen; Zhou, Tian; Li, Ruo

2015-09-17

The multipath spread in underwater acoustic channels is severe and, therefore, when the symbol rate of the time reversal (TR) acoustic communication using single-carrier (SC) modulation is high, the large intersymbol interference (ISI) span caused by multipath reduces the performance of the TR process and needs to be removed using the long adaptive equalizer as the post-processor. In this paper, a TR acoustic communication method using filtered multitone (FMT) modulation is proposed in order to reduce the residual ISI in the processed signal using TR. In the proposed method, FMT modulation is exploited to modulate information symbols onto separate subcarriers with high spectral containment and TR technique, as well as adaptive equalization is adopted at the receiver to suppress ISI and noise. The performance of the proposed method is assessed through simulation and real data from a trial in an experimental pool. The proposed method was compared with the TR acoustic communication using SC modulation with the same spectral efficiency. Results demonstrate that the proposed method can improve the performance of the TR process and reduce the computational complexity of adaptive equalization for post-process.

OLT-centralized sampling frequency offset compensation scheme for OFDM-PON.

PubMed

Chen, Ming; Zhou, Hui; Zheng, Zhiwei; Deng, Rui; Chen, Qinghui; Peng, Miao; Liu, Cuiwei; He, Jing; Chen, Lin; Tang, Xionggui

2017-08-07

We propose an optical line terminal (OLT)-centralized sampling frequency offset (SFO) compensation scheme for adaptively-modulated OFDM-PON systems. By using the proposed SFO scheme, the phase rotation and inter-symbol interference (ISI) caused by SFOs between OLT and multiple optical network units (ONUs) can be centrally compensated in the OLT, which reduces the complexity of ONUs. Firstly, the optimal fast Fourier transform (FFT) size is identified in the intensity-modulated and direct-detection (IMDD) OFDM system in the presence of SFO. Then, the proposed SFO compensation scheme including phase rotation modulation (PRM) and length-adaptive OFDM frame has been experimentally demonstrated in the downlink transmission of an adaptively modulated optical OFDM with the optimal FFT size. The experimental results show that up to ± 300 ppm SFO can be successfully compensated without introducing any receiver performance penalties.

Computerized Adaptive Testing (CAT): A User Manual

DTIC Science & Technology

1984-03-12

NPRDC TR 84-32 COMPUTERIZED ADAPTIVE TESTING ( CAT ): A USER MANUAL Susan Hardwick Lawrence Eastman Ross Cooper Rehab Group, Incorporated San...a ~EI’IOD COVIRED COMPUTERIZED ADAPTIVE TESTING ( CAT ) Final Report Aug 1981-June 1982 A USER MANUAL 1. ~l:l’t,ORMINCI ORCI. RE~ORT NUM.I:R 62-83...II nee• .. _, entl ldentll)’ ,,. llloclr _,.,) A joint-service effort is underway to develop a computerized adaptive testing ( CAT ) system and to

A compact roller-gear pitch-yaw joint module: Design and control issues

NASA Technical Reports Server (NTRS)

Dohring, Mark E.; Anderson, William J.; Newman, Wyatt S.; Rohn, Douglas A.

1993-01-01

Robotic systems have been proposed as a means of accomplishing assembly and maintenance tasks in space. The desirable characteristics of these systems include compact size, low mass, high load capacity, and programmable compliance to improve assembly performance. In addition, the mechanical system must transmit power in such a way as to allow high performance control of the system. Efficiency, linearity, low backlash, low torque ripple, and low friction are all desirable characteristics. This work presents a pitch-yaw joint module designed and built to address these issues. Its effectiveness as a two degree-of-freedom manipulator using natural admittance control, a method of force control, is demonstrated.

A Modular Soft Robotic Wrist for Underwater Manipulation.

PubMed

Kurumaya, Shunichi; Phillips, Brennan T; Becker, Kaitlyn P; Rosen, Michelle H; Gruber, David F; Galloway, Kevin C; Suzumori, Koichi; Wood, Robert J

2018-04-19

This article presents the development of modular soft robotic wrist joint mechanisms for delicate and precise manipulation in the harsh deep-sea environment. The wrist consists of a rotary module and bending module, which can be combined with other actuators as part of a complete manipulator system. These mechanisms are part of a suite of soft robotic actuators being developed for deep-sea manipulation via submersibles and remotely operated vehicles, and are designed to be powered hydraulically with seawater. The wrist joint mechanisms can also be activated with pneumatic pressure for terrestrial-based applications, such as automated assembly and robotic locomotion. Here we report the development and characterization of a suite of rotary and bending modules by varying fiber number and silicone hardness. Performance of the complete soft robotic wrist is demonstrated in normal atmospheric conditions using both pneumatic and hydraulic pressures for actuation and under high ambient hydrostatic pressures equivalent to those found at least 2300 m deep in the ocean. This rugged modular wrist holds the potential to be utilized at full ocean depths (>10,000 m) and is a step forward in the development of jointed underwater soft robotic arms.

Standing on slopes - how current microprocessor-controlled prosthetic feet support transtibial and transfemoral amputees in an everyday task.

PubMed

Ernst, Michael; Altenburg, Björn; Bellmann, Malte; Schmalz, Thomas

2017-11-16

Conventional prosthetic feet like energy storage and return feet provide only a limited range of ankle motion compared to human ones. In order to overcome the poor rotational adaptability, prosthetic manufacturers developed different prosthetic feet with an additional rotational joint and implemented active control in different states. It was the aim of the study to investigate to what extent these commercially available microprocessor-controlled prosthetic feet support a natural posture while standing on inclines and which concept is most beneficial for lower limb amputees. Four unilateral transtibial and four unilateral transfemoral amputees participated in the study. Each of the subjects wore five different microprocessor-controlled prosthetic feet in addition to their everyday feet. The subjects were asked to stand on slopes of different inclinations (level ground, upward slope of 10°, and downward slope of -10°). Vertical ground reaction forces, joint torques and joint angles in the sagittal plane were measured for both legs separately for the different situations and compared to a non-amputee reference group. Differences in the biomechanical parameters were observed between the different prosthetic feet and compared to the reference group for the investigated situations. They were most prominent while standing on a downward slope. For example, on the prosthetic side, the vertical ground reaction force is reduced by about 20%, and the torque about the knee acts to flex the joint for feet that are not capable of a full adaptation to the downward slope. In contrast, fully adaptable feet with an auto-adaptive dorsiflexion stop show no changes in vertical ground reaction forces and knee extending torques. A prosthetic foot that provides both, an auto-adaptive dorsiflexion stop and a sufficient range of motion for fully adapting to inclinations appears to be the key element in the prosthetic fitting for standing on inclinations in lower limb amputees. In such situations, this prosthetic concept appears superior to both, conventional feet with passive structures as well as feet that solely provide a sufficient range of motion. The results also indicate that both, transfemoral and transtibial amputees benefit from such a foot.

Ipsilesional motor deficits following stroke reflect hemispheric specializations for movement control.

PubMed

Schaefer, Sydney Y; Haaland, Kathleen Y; Sainburg, Robert L

2007-08-01

Recent reports of functional impairment in the 'unaffected' limb of stroke patients have suggested that these deficits vary with the side of lesion. This not only supports the idea that the ipsilateral hemisphere contributes to arm movements, but also implies that such contributions are lateralized. We have previously suggested that the left and right hemispheres are specialized for controlling different features of movement. In reaching movements, the non-dominant arm appears better adapted for achieving accurate final positions and the dominant arm for specifying initial trajectory features, such as movement direction and peak acceleration. The purpose of this study was to determine whether different features of control could characterize ipsilesional motor deficits following stroke. Healthy control subjects and patients with either left- or right-hemisphere damage performed targeted single-joint elbow movements of different amplitudes in their ipsilateral hemispace. We predicted that left-hemisphere damage would produce deficits in specification of initial trajectory features, while right-hemisphere damage would produce deficits in final position accuracy. Consistent with our predictions, patients with left, but not right, hemisphere damage showed reduced modulation of acceleration amplitude. However, patients with right, but not left, hemisphere damage showed significantly larger errors in final position, which corresponded to reduced modulation of acceleration duration. Neither patient group differed from controls in terms of movement speed. Instead, the mechanisms by which speed was specified, through modulation of acceleration amplitude and modulation of acceleration duration, appeared to be differentially affected by left- and right-hemisphere damage. These findings support the idea that each hemisphere contributes differentially to the control of initial trajectory and final position, and that ipsilesional deficits following stroke reflect this lateralization in control.

Ion transport membrane module and vessel system with directed internal gas flow

DOEpatents

Holmes, Michael Jerome; Ohrn, Theodore R.; Chen, Christopher Ming-Poh

2010-02-09

An ion transport membrane system comprising (a) a pressure vessel having an interior, an inlet adapted to introduce gas into the interior of the vessel, an outlet adapted to withdraw gas from the interior of the vessel, and an axis; (b) a plurality of planar ion transport membrane modules disposed in the interior of the pressure vessel and arranged in series, each membrane module comprising mixed metal oxide ceramic material and having an interior region and an exterior region; and (c) one or more gas flow control partitions disposed in the interior of the pressure vessel and adapted to change a direction of gas flow within the vessel.

Design of a biologically inspired lower limb exoskeleton for human gait rehabilitation.

PubMed

Lyu, Mingxing; Chen, Weihai; Ding, Xilun; Wang, Jianhua; Bai, Shaoping; Ren, Huichao

2016-10-01

This paper proposes a novel bionic model of the human leg according to the theory of physiology. Based on this model, we present a biologically inspired 3-degree of freedom (DOF) lower limb exoskeleton for human gait rehabilitation, showing that the lower limb exoskeleton is fully compatible with the human knee joint. The exoskeleton has a hybrid serial-parallel kinematic structure consisting of a 1-DOF hip joint module and a 2-DOF knee joint module in the sagittal plane. A planar 2-DOF parallel mechanism is introduced in the design to fully accommodate the motion of the human knee joint, which features not only rotation but also relative sliding. Therefore, the design is consistent with the requirements of bionics. The forward and inverse kinematic analysis is studied and the workspace of the exoskeleton is analyzed. The structural parameters are optimized to obtain a larger workspace. The results using MATLAB-ADAMS co-simulation are shown in this paper to demonstrate the feasibility of our design. A prototype of the exoskeleton is also developed and an experiment performed to verify the kinematic analysis. Compared with existing lower limb exoskeletons, the designed mechanism has a large workspace, while allowing knee joint rotation and small amount of sliding.

Design of a biologically inspired lower limb exoskeleton for human gait rehabilitation

NASA Astrophysics Data System (ADS)

Lyu, Mingxing; Chen, Weihai; Ding, Xilun; Wang, Jianhua; Bai, Shaoping; Ren, Huichao

2016-10-01

This paper proposes a novel bionic model of the human leg according to the theory of physiology. Based on this model, we present a biologically inspired 3-degree of freedom (DOF) lower limb exoskeleton for human gait rehabilitation, showing that the lower limb exoskeleton is fully compatible with the human knee joint. The exoskeleton has a hybrid serial-parallel kinematic structure consisting of a 1-DOF hip joint module and a 2-DOF knee joint module in the sagittal plane. A planar 2-DOF parallel mechanism is introduced in the design to fully accommodate the motion of the human knee joint, which features not only rotation but also relative sliding. Therefore, the design is consistent with the requirements of bionics. The forward and inverse kinematic analysis is studied and the workspace of the exoskeleton is analyzed. The structural parameters are optimized to obtain a larger workspace. The results using MATLAB-ADAMS co-simulation are shown in this paper to demonstrate the feasibility of our design. A prototype of the exoskeleton is also developed and an experiment performed to verify the kinematic analysis. Compared with existing lower limb exoskeletons, the designed mechanism has a large workspace, while allowing knee joint rotation and small amount of sliding.

ASTP crewmen in Docking Module trainer during training session at JSC

NASA Technical Reports Server (NTRS)

1975-01-01

An interior view of the Docking Module trainer in bldg 35 during Apollo Soyuz Test Project (ASTP) joint crew training at JSC. Astronaut Donald K. Slayton (right) is the docking module pilot of the American ASTP prime crew. The other man is Cosmonaut Valeriy N. Kubasov, engineer on the Soviet ASTP first (prime) crew. The training session simulated activities on the second day in space. The Docking module is designed to link the Apollo and Soyuz spacecraft.

A Study of the Time Dependence in Fracture Processes Relating to Service Life Prediction of Adhesive Joints and Advanced Composites.

DTIC Science & Technology

1981-04-30

fluid temperature should exceed 145°F. The flow control module contains all the hydraulic circuit elements necessary for both the pressure line to and...are contained in three basic modules : 1) the hydraulic power supply, 2) a flow control module containing valving, accumulators and filters, and 3) the...hydraulic transient overpressures, is located in the flow control module , as are the high and low pressure filters. The load frame (MTS Systems Corp

An 802.11 n wireless local area network transmission scheme for wireless telemedicine applications.

PubMed

Lin, C F; Hung, S I; Chiang, I H

2010-10-01

In this paper, an 802.11 n transmission scheme is proposed for wireless telemedicine applications. IEEE 802.11n standards, a power assignment strategy, space-time block coding (STBC), and an object composition Petri net (OCPN) model are adopted. With the proposed wireless system, G.729 audio bit streams, Joint Photographic Experts Group 2000 (JPEG 2000) clinical images, and Moving Picture Experts Group 4 (MPEG-4) video bit streams achieve a transmission bit error rate (BER) of 10-7, 10-4, and 103 simultaneously. The proposed system meets the requirements prescribed for wireless telemedicine applications. An essential feature of this proposed transmission scheme is that clinical information that requires a high quality of service (QoS) is transmitted at a high power transmission rate with significant error protection. For maximizing resource utilization and minimizing the total transmission power, STBC and adaptive modulation techniques are used in the proposed 802.11 n wireless telemedicine system. Further, low power, direct mapping (DM), low-error protection scheme, and high-level modulation are adopted for messages that can tolerate a high BER. With the proposed transmission scheme, the required reliability of communication can be achieved. Our simulation results have shown that the proposed 802.11 n transmission scheme can be used for developing effective wireless telemedicine systems.

A novel algorithm for Bluetooth ECG.

PubMed

Pandya, Utpal T; Desai, Uday B

2012-11-01

In wireless transmission of ECG, data latency will be significant when battery power level and data transmission distance are not maintained. In applications like home monitoring or personalized care, to overcome the joint effect of previous issues of wireless transmission and other ECG measurement noises, a novel filtering strategy is required. Here, a novel algorithm, identified as peak rejection adaptive sampling modified moving average (PRASMMA) algorithm for wireless ECG is introduced. This algorithm first removes error in bit pattern of received data if occurred in wireless transmission and then removes baseline drift. Afterward, a modified moving average is implemented except in the region of each QRS complexes. The algorithm also sets its filtering parameters according to different sampling rate selected for acquisition of signals. To demonstrate the work, a prototyped Bluetooth-based ECG module is used to capture ECG with different sampling rate and in different position of patient. This module transmits ECG wirelessly to Bluetooth-enabled devices where the PRASMMA algorithm is applied on captured ECG. The performance of PRASMMA algorithm is compared with moving average and S-Golay algorithms visually as well as numerically. The results show that the PRASMMA algorithm can significantly improve the ECG reconstruction by efficiently removing the noise and its use can be extended to any parameters where peaks are importance for diagnostic purpose.

Joint representation of translational and rotational components of optic flow in parietal cortex

PubMed Central

Sunkara, Adhira; DeAngelis, Gregory C.; Angelaki, Dora E.

2016-01-01

Terrestrial navigation naturally involves translations within the horizontal plane and eye rotations about a vertical (yaw) axis to track and fixate targets of interest. Neurons in the macaque ventral intraparietal (VIP) area are known to represent heading (the direction of self-translation) from optic flow in a manner that is tolerant to rotational visual cues generated during pursuit eye movements. Previous studies have also reported that eye rotations modulate the response gain of heading tuning curves in VIP neurons. We tested the hypothesis that VIP neurons simultaneously represent both heading and horizontal (yaw) eye rotation velocity by measuring heading tuning curves for a range of rotational velocities of either real or simulated eye movements. Three findings support the hypothesis of a joint representation. First, we show that rotation velocity selectivity based on gain modulations of visual heading tuning is similar to that measured during pure rotations. Second, gain modulations of heading tuning are similar for self-generated eye rotations and visually simulated rotations, indicating that the representation of rotation velocity in VIP is multimodal, driven by both visual and extraretinal signals. Third, we show that roughly one-half of VIP neurons jointly represent heading and rotation velocity in a multiplicatively separable manner. These results provide the first evidence, to our knowledge, for a joint representation of translation direction and rotation velocity in parietal cortex and show that rotation velocity can be represented based on visual cues, even in the absence of efference copy signals. PMID:27095846

Human Machine Learning Symbiosis

ERIC Educational Resources Information Center

Walsh, Kenneth R.; Hoque, Md Tamjidul; Williams, Kim H.

2017-01-01

Human Machine Learning Symbiosis is a cooperative system where both the human learner and the machine learner learn from each other to create an effective and efficient learning environment adapted to the needs of the human learner. Such a system can be used in online learning modules so that the modules adapt to each learner's learning state both…

Orion EM-1 Crew Module Adapter Lift & Move to Stand

NASA Image and Video Library

2016-11-11

The Orion crew module adapter (CMA) for Exploration Mission 1 was lifted for the first and only time, Nov. 11, during its processing flow inside the Neil Armstrong Operations and Checkout (O&C) Building high bay at the agency's Kennedy Space Center in Florida. The CMA is now undergoing secondary structure outfitting.

Timothy Silverman | NREL

Science.gov Websites

physical phenomena, PV package reliability, and outdoor PV performance. At NREL, he performs research in advanced concept PV modules. Dr. Silverman studies the performance and reliability of PV modules, including previously studied the degradation of solder joints in high-concentration PV and the outdoor performance of

Environmentally adaptive processing for shallow ocean applications: A sequential Bayesian approach.

PubMed

Candy, J V

2015-09-01

The shallow ocean is a changing environment primarily due to temperature variations in its upper layers directly affecting sound propagation throughout. The need to develop processors capable of tracking these changes implies a stochastic as well as an environmentally adaptive design. Bayesian techniques have evolved to enable a class of processors capable of performing in such an uncertain, nonstationary (varying statistics), non-Gaussian, variable shallow ocean environment. A solution to this problem is addressed by developing a sequential Bayesian processor capable of providing a joint solution to the modal function tracking and environmental adaptivity problem. Here, the focus is on the development of both a particle filter and an unscented Kalman filter capable of providing reasonable performance for this problem. These processors are applied to hydrophone measurements obtained from a vertical array. The adaptivity problem is attacked by allowing the modal coefficients and/or wavenumbers to be jointly estimated from the noisy measurement data along with tracking of the modal functions while simultaneously enhancing the noisy pressure-field measurements.

A video coding scheme based on joint spatiotemporal and adaptive prediction.

PubMed

Jiang, Wenfei; Latecki, Longin Jan; Liu, Wenyu; Liang, Hui; Gorman, Ken

2009-05-01

We propose a video coding scheme that departs from traditional Motion Estimation/DCT frameworks and instead uses Karhunen-Loeve Transform (KLT)/Joint Spatiotemporal Prediction framework. In particular, a novel approach that performs joint spatial and temporal prediction simultaneously is introduced. It bypasses the complex H.26x interframe techniques and it is less computationally intensive. Because of the advantage of the effective joint prediction and the image-dependent color space transformation (KLT), the proposed approach is demonstrated experimentally to consistently lead to improved video quality, and in many cases to better compression rates and improved computational speed.

The design and development of a triaxial wear-testing joint simulator.

PubMed

Green, A S; O'Connell, M K; Lyons, A S; James, S P

1999-01-01

Most of the existing wear testers created to wear test total hip replacements, specifically the acetabular component, are designed to exert only an axial force and provide rotation in a close approximation of the actual femoral movement. The Rocky Mountain Joint Simulator was designed to exert three orthogonal forces and provide rotations about the X-, Y- and Z-axes to more closely simulate the physiological forces and motions found in the human gait cycle. The RMJS was also designed with adaptability for other joints, such as knees or canine hips, through the use of hydraulics and a computer-programmable control system. Such adaptability and functionality allows the researcher to more closely model a gait cycle, thereby obtaining wear patterns that resemble those found in retrieved implants more closely than existing simulators. Research is ongoing into the tuning and evaluation of the machine and preliminary acetabular component wear test results will be presented at the conference.

Evaluation of a software module for adaptive treatment planning and re-irradiation.

PubMed

Richter, Anne; Weick, Stefan; Krieger, Thomas; Exner, Florian; Kellner, Sonja; Polat, Bülent; Flentje, Michael

2017-12-28

The aim of this work is to validate the Dynamic Planning Module in terms of usability and acceptance in the treatment planning workflow. The Dynamic Planning Module was used for decision making whether a plan adaptation was necessary within one course of radiation therapy. The Module was also used for patients scheduled for re-irradiation to estimate the dose in the pretreated region and calculate the accumulated dose to critical organs at risk. During one year, 370 patients were scheduled for plan adaptation or re-irradiation. All patient cases were classified according to their treated body region. For a sub-group of 20 patients treated with RT for lung cancer, the dosimetric effect of plan adaptation during the main treatment course was evaluated in detail. Changes in tumor volume, frequency of re-planning and the time interval between treatment start and plan adaptation were assessed. The Dynamic Planning Tool was used in 20% of treated patients per year for both approaches nearly equally (42% plan adaptation and 58% re-irradiation). Most cases were assessed for the thoracic body region (51%) followed by pelvis (21%) and head and neck cases (10%). The sub-group evaluation showed that unintended plan adaptation was performed in 38% of the scheduled cases. A median time span between first day of treatment and necessity of adaptation of 17 days (range 4-35 days) was observed. PTV changed by 12 ± 12% on average (maximum change 42%). PTV decreased in 18 of 20 cases due to tumor shrinkage and increased in 2 of 20 cases. Re-planning resulted in a reduction of the mean lung dose of the ipsilateral side in 15 of 20 cases. The experience of one year showed high acceptance of the Dynamic Planning Module in our department for both physicians and medical physicists. The re-planning can potentially reduce the accumulated dose to the organs at risk and ensure a better target volume coverage. In the re-irradiation situation, the Dynamic Planning Tool was used to consider the pretreatment dose, to adapt the actual treatment schema more specifically and to review the accumulated dose.

Optimization of the Robotic Joint Equipped with Epicyloidal Gear and Direct Drive for Space Applications

NASA Astrophysics Data System (ADS)

Seweryn, Karol; Grassmann, Kamil; Ciesielska, Monika; Rybus, Tomasz; Turek, Michal

2013-09-01

One of the most critical element in the orbital manipulators are kinematic joints. Joints must be adapted to work in tough conditions of space environment and must ensure the greatest efficiency and work without backlash. At the Space Mechatronics and Robotics Laboratory (LMRS) of the Space Research Centre, PAS our team designed and built a lightweight kinematic pair based on a new concept. The new concept is based on the epicycloid two-stage gearbox with torque motor. In this paper we have focused on optimization of the joint design for space application. The optimization was focused on the minimization of the mass and backlash effects and on maximizing the joint efficiency.

Rotor component displacement measurement system

DOEpatents

Mercer, Gary D.; Li, Ming C.; Baum, Charles R.

2003-05-27

A measuring system for measuring axial displacement of a tube relative to an axially stationary component in a rotating rotor assembly includes at least one displacement sensor adapted to be located normal to a longitudinal axis of the tube; an insulated cable system adapted for passage through the rotor assembly; a rotatable proximitor module located axially beyond the rotor assembly to which the cables are connected; and a telemetry system operatively connected to the proximitor module for sampling signals from the proximitor module and forwarding data to a ground station.

Orion Crew Module Adapter-Structural Test Article and European S

NASA Image and Video Library

2017-05-09

Inside the Neil Armstrong Operations and Checkout Building high bay at NASA's Kennedy Space Center in Florida, operations are underway to lower the Orion crew module adapter structural test article onto the European Space Agency's service module structural test article. After the hardware is attached, the structure will be packed and shipped to Lockheed Martin's Denver facility to undergo testing. The Orion spacecraft will launch atop the agency's Space Launch System rocket on Exploration Mission-1 in 2019.

Experimental demonstration of real-time adaptively modulated DDO-OFDM systems with a high spectral efficiency up to 5.76bit/s/Hz transmission over SMF links.

PubMed

Chen, Ming; He, Jing; Tang, Jin; Wu, Xian; Chen, Lin

2014-07-28

In this paper, a FPGAs-based real-time adaptively modulated 256/64/16QAM-encoded base-band OFDM transceiver with a high spectral efficiency up to 5.76bit/s/Hz is successfully developed, and experimentally demonstrated in a simple intensity-modulated direct-detection optical communication system. Experimental results show that it is feasible to transmit a raw signal bit rate of 7.19Gbps adaptively modulated real-time optical OFDM signal over 20km and 50km single mode fibers (SMFs). The performance comparison between real-time and off-line digital signal processing is performed, and the results show that there is a negligible power penalty. In addition, to obtain the best transmission performance, direct-current (DC) bias voltage for MZM and launch power into optical fiber links are explored in the real-time optical OFDM systems.

Underwater wireless optical MIMO system with spatial modulation and adaptive power allocation

NASA Astrophysics Data System (ADS)

Huang, Aiping; Tao, Linwei; Niu, Yilong

2018-04-01

In this paper, we investigate the performance of underwater wireless optical multiple-input multiple-output communication system combining spatial modulation (SM-UOMIMO) with flag dual amplitude pulse position modulation (FDAPPM). Channel impulse response for coastal and harbor ocean water links are obtained by Monte Carlo (MC) simulation. Moreover, we obtain the closed-form and upper bound average bit error rate (BER) expressions for receiver diversity including optical combining, equal gain combining and selected combining. And a novel adaptive power allocation algorithm (PAA) is proposed to minimize the average BER of SM-UOMIMO system. Our numeric results indicate an excellent match between the analytical results and numerical simulations, which confirms the accuracy of our derived expressions. Furthermore, the results show that adaptive PAA outperforms conventional fixed factor PAA and equal PAA obviously. Multiple-input single-output system with adaptive PAA obtains even better BER performance than MIMO one, at the same time reducing receiver complexity effectively.

Disassemblability modeling technology of configurable product based on disassembly constraint relation weighted design structure matrix(DSM)

NASA Astrophysics Data System (ADS)

Qiu, Lemiao; Liu, Xiaojian; Zhang, Shuyou; Sun, Liangfeng

2014-05-01

The current research of configurable product disassemblability focuses on disassemblability evaluation and disassembly sequence planning. Little work has been done on quantitative analysis of configurable product disassemblability. The disassemblability modeling technology for configurable product based on disassembly constraint relation weighted design structure matrix (DSM) is proposed. Major factors affecting the disassemblability of configurable product are analyzed, and the disassembling degrees between components in configurable product are obtained by calculating disassembly entropies such as joint type, joint quantity, disassembly path, disassembly accessibility and material compatibility. The disassembly constraint relation weighted DSM of configurable product is constructed and configuration modules are formed by matrix decomposition and tearing operations. The disassembly constraint relation in configuration modules is strong coupling, and the disassembly constraint relation between modules is weak coupling, and the disassemblability configuration model is constructed based on configuration module. Finally, taking a hydraulic forging press as an example, the decomposed weak coupling components are used as configuration modules alone, components with a strong coupling are aggregated into configuration modules, and the disassembly sequence of components inside configuration modules is optimized by tearing operation. A disassemblability configuration model of the hydraulic forging press is constructed. By researching the disassemblability modeling technology of product configuration design based on disassembly constraint relation weighted DSM, the disassembly property in maintenance, recycling and reuse of configurable product are optimized.

The Influence of Social and Nonsocial Variables on the Simon Effect.

PubMed

Mussi, Davide R; Marino, Barbara F M; Riggio, Lucia

2015-01-01

Recently, the Simon effect (SE) has been observed in social contexts when two individuals share a two-choice task. This joint SE (JSE) has been interpreted as evidence that people co-represent their actions. However, it is still not clear if the JSE is driven by social factors or low-level mechanisms. To address this question, we applied a common paradigm to a joint Simon task (Experiments 1 and 4), a standard Simon task (Experiment 2), and a go/no-go task (Experiment 3). The results showed that both the JSE and the SE were modulated by the repetition/non-repetition of task features. Moreover, the JSE was differently modulated by the gender composition of the two individuals involved in the shared task and by their interpersonal relationship. Taken together, our results do not support a pure social explanation of the JSE, nevertheless, they show the independent role of different social factors in modulating the effect.

Performance of adaptive DD-OFDM multicore fiber links and its relation with intercore crosstalk.

PubMed

Alves, Tiago M F; Luís, Ruben S; Puttnam, Benjamin J; Cartaxo, Adolfo V T; Awaji, Yoshinari; Wada, Naoya

2017-07-10

Adaptive direct-detection (DD) orthogonal frequency-division multiplexing (OFDM) is proposed to guarantee signal quality over time in weakly-coupled homogenous multicore fiber (MCFs) links impaired by stochastic intercore crosstalk (ICXT). For the first time, the received electrical power of the ICXT and the performance of the adaptive DD-OFDM MCF link are experimentally monitored quasi-simultaneously over a 210 hour period. Experimental results show that the time evolution of the error vector magnitude due to the ICXT can be suitably estimated from the normalized power of the detected crosstalk. The detected crosstalk results from the beating between the carrier in the test core and ICXT originating from the carrier and modulated signal from interfering core. The results show that the operation of DD-OFDM systems employing fixed modulation can be severely impaired by the presence of ICXT that may unpredictable vary in both power and frequency. The system may suffer from deleterious impact of moderate ICXT levels over a time duration of several hours or from peak ICXT levels occurring over a number of minutes. Such power fluctuations can lead to large variations in bit error ratio (BER) for static modulation schemes. Here, we show that BER fluctuations may be minimized by the use of adaptive modulation techniques and that in particular, the adaptive OFDM is a viable solution to guarantee link quality in MCF-based systems. An experimental model of an adaptive DD-OFDM MCF link shows an average throughput of 12 Gb/s that represents a reduction of only 9% compared to the maximum throughput measured without ICXT and an improvement of 23% relative to throughput obtained with static modulation.

The Functional Anatomy of the Carpometacarpal Complex in Anthropoids and Its Implications for the Evolution of the Hominoid Hand.

PubMed

Selby, Michael S; Simpson, Scott W; Lovejoy, C Owen

2016-05-01

Previously, we described several features of the carpometacarpal joints in extant large-bodied apes that are likely adaptations to the functional demands of vertical climbing and suspension. We observed that all hominids, including modern humans and the 4.4-million-year-old hominid Ardipithecus ramidus, lacked these features. Here, we assess the uniqueness of these features in a large sample of monkey, ape, and human hands. These new data provide additional insights into the functional adaptations and evolution of the anthropoid hand. Our survey highlights a series of anatomical adaptations that restrict motion between the second and third metacarpals (MC2 and MC3) and their associated carpals in extant apes, achieved via joint reorganization and novel energy dissipation mechanisms. Their hamate-MC4 and -MC5 joint surface morphologies suggest limited mobility, at least in Pan. Gibbons and spider monkeys have several characters (angled MC3, complex capitate-MC3 joint topography, variably present capitate-MC3 ligaments) that suggest functional convergence in response to suspensory locomotion. Baboons have carpometacarpal morphology suggesting flexion/extension at these joints beyond that observed in most other Old World monkeys, probably as an energy dissipating mechanism minimizing collision forces during terrestrial locomotion. All hominids lack these specializations of the extant great apes, suggesting that vertical climbing was never a central feature of our ancestral locomotor repertoire. Furthermore, the reinforced carpometacarpus of vertically climbing African apes was likely appropriated for knuckle-walking in concert with other novel potential energy dissipating mechanisms. The most parsimonious explanation of the structural similarity of these carpometacarpal specializations in great apes is that they evolved independently. © 2016 Wiley Periodicals, Inc.

Processing of NiTi Reinforced Adaptive Solder for Electronic Packaging

DTIC Science & Technology

2004-03-01

NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA THESIS PROCESSING OF NITI REINFORCED ADAPTIVE SOLDER FOR ELECTRONIC PACKAGING...March 2004 3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE: Processing of NiTi Reinforced Adaptive Solder for Electronic...reports in the development a process to fabricate solder joints with a fine distribution of shape memory alloys (SMA) NiTi particulates. The

Opposite Effects of Stress on Pain Modulation Depend on the Magnitude of Individual Stress Response.

PubMed

Geva, Nirit; Defrin, Ruth

2018-04-01

The effect of acute stress on pain threshold and intolerance threshold are reported as producing either hypoalgesia or hyperalgesia. Yet, the contribution of individual stress reactivity in this respect has not been established. The aim was to test 2 pain modulation paradigms under acute stress manipulation, to our knowledge, for the first time, to study whether stress differentially affects pain modulation, and whether the effect is related to individual stress response. Participants were 31 healthy subjects. Conditioned pain modulation (CPM) and pain adaptation were measured before and after inducing an acute stress response using the Montreal Imaging Stress Task. Subjects' stress response was evaluated according to salivary cortisol, autonomic function, and perceived stress and anxiety. The Montreal Imaging Stress Task induced a validated stress response. On a group level, stress induced reduction in CPM magnitude and increase in pain adaptation compared with baseline. These responses correlated with stress reactivity. When the group was subdivided according to stress reactivity, only high stress responders exhibited reduced CPM whereas only low stress responders exhibited increased pain adaptation. The results suggest that acute stress may induce opposite effects on pain modulation, depending on individual stress reactivity magnitude, with an advantage to low stress responders. This study evaluated the effect of acute stress on pain modulation. Pain modulation under stress is affected by individual stress responsiveness; decreased CPM occurs in high stress responders whereas increased pain adaptation occurs in low stress responders. Identification of high stress responders may promote better pain management. Copyright © 2017 The American Pain Society. Published by Elsevier Inc. All rights reserved.

Explosive Joining for Nuclear-Reactor Repair

NASA Technical Reports Server (NTRS)

Bement, L. J.; Bailey, J. W.

1983-01-01

In explosive joining technique, adapter flange from fuel channel machined to incorporate a V-notch interface. Ribbon explosive, 1/2 inch (1.3 cm) in width, drives V-notched wall of adapter into bellows assembly, producing atomic-level metallurgical bond. Ribbon charge yields joint with double parent metal strength.

Research Status on Bonding Behavior of Prefabricated Concrete Shear Wall

NASA Astrophysics Data System (ADS)

Wang, Donghui; Liu, Xudong; Wang, Sheng; Li, Shanshan

2018-03-01

Prefabricated shear wall structure adapts to the development and requirements of China’s residential industrialization. The key to the prefabricated concrete shear wall structure is the connection between the prefabricated members, where the reliability of the connection of the concrete joint is related to the overall performance and seismic effect of the structure. In this paper, the microstructures of the joint surface and shear properties are analysed, and the formula for calculating the shear strength of the joint is obtained.

Development of an Underactuated 2-DOF Wrist Joint using McKibben PAMs

NASA Astrophysics Data System (ADS)

Rajagopal, S. P.; Jain, S.; Ramasubramanian, S. N.; Johnson, B. V.; Dwivedy, S. K.

2014-10-01

In this work, model of an underactuated 2-DOF wrist joint with pneumatically actuated muscles is proposed. For the joint, McKibben-type artificial muscles are used in parallel configuration for the actuation. For each Degree of Freedom (DOF) one agonist-antagonist pair arrangement is usually used with a pulley mechanism. A mathematical model of wrist joint is derived using conventional forward kinematic analysis. The static model relating pressure in the muscle with the orientation of the wrist joint is obtained by combining the experimental data and mathematical model. Regulation of pressure can be achieved by pulse width modulation control of on/off solenoid valves. A set of free vibration experiments are done for the dynamic identification of the muscle characteristics.

Gait Characteristics When Walking on Different Slippery Walkways.

PubMed

Whitmore, Mariah W; Hargrove, Levi J; Perreault, Eric J

2016-01-01

This study sought to determine the changes in muscle activity about the ankle, knee, and hip in able-bodied people walking at steady state on surfaces with different degrees of slipperiness. Muscle activity was measured through electromyographic signals from selected lower limb muscles and quantified to directly compare changes across surface conditions. Our results showed distinct changes in the patterns of muscle activity controlling each joint. Muscles controlling the ankle showed a significant reduction in activity as the surface became more slippery, presumably resulting in a compliant distal joint to facilitate full contact with the surface. Select muscles about the knee and hip showed a significant increase in activity as the surface became more slippery. This resulted in increased knee and hip flexion likely contributing to a lowering of the body's center of mass and stabilization of the proximal leg and trunk. These findings suggest a proximal-distal gradient in the control of muscle activity that could inform the future design of adaptable prosthetic controllers. Walking on a slippery surface is extremely difficult, especially for individuals with lower limb amputations because current prostheses do not allow the compensatory changes in lower limb dynamics that occur involuntarily in unimpaired subjects. With recent advances in prosthetic control, there is the potential to provide some of these compensatory changes; however, we first need to understand how able-bodied individuals modulate their gait under these challenging conditions.

Capacity building from the inside out: development and evaluation of a CITI ethics certification training module for American Indian and Alaska Native community researchers.

PubMed

Pearson, Cynthia R; Parker, Myra; Fisher, Celia B; Moreno, Claudia

2014-02-01

Current human subject research training modules fail to capture ethically relevant cultural aspects of research involving American Indian and Alaska Native (AI/AN) community members. Applying a Community Engaged Research (CEnR) approach, we adapted the Collaborative IRB Training Initiative training module "assessing risk and benefits." In a two-arm randomized controlled trial, followed by debriefing interviews, we evaluated module acceptability and understandability (test scores) among 40 reservation-based community members. Participants who took the adapted module, compared to those who took the standard module, reported higher scores on relevance of the material overall satisfaction, module quiz scores, and a trend toward higher self-efficacy. Implications of the efficacy of this approach for enhancing ethics training and community participation in research within AI/AN and other cultural populations within and outside the United States are discussed.

Atlantis returns to VAB after beginning rollout to the pad

NASA Technical Reports Server (NTRS)

2001-01-01

KENNEDY SPACE CENTER, Fla. -- Scattered clouds cast shadows as Space Shuttle Atlantis crawls back inside the Vehicle Assembly Building high bay 1. After earlier starting its trek to Launch Pad 39B, Atlantis was returned to the VAB due to lightning in the area. To the left of the VAB is the Launch Control Center. The four-story building houses the firing rooms that are used to conduct Space Shuttle launches. Leading away from the VAB, in the foreground, is the crawlerway, the 130-foot-wide road specially constructed to transport the Shuttle, mobile launcher platform and crawler-transporter with a combined weight of about 17 million pounds. Space Shuttle Atlantis is targeted for launch no earlier than July 12 on mission STS-104, the 10th flight to the International Space Station. The payload on the 11-day mission is the Joint Airlock Module, which will allow astronauts and cosmonauts in residence on the Station to perform future spacewalks without the presence of a Space Shuttle. The module, which comprises a crew lock and an equipment lock, will be connected to the starboard (right) side of Node 1 Unity. Atlantis will also carry oxygen and nitrogen storage tanks, vital to operation of the Joint Airlock, on a Spacelab Logistics Double Pallet in the payload bay. The tanks, to be installed on the perimeter of the Joint Module during the missions spacewalks, will support future spacewalk operations and experiments plus augment the resupply system for the Stations Service Module.

Water System Adaptation to Hydrological Changes: Module 2, Stormwater Management and Sewer Performance under Intense Storms: Case Study from Lawrence, Massachusetts, U.S.A.

EPA Science Inventory

This course focuses on water system adaptation to short-term and long-term climate and hydrologic stressors that affect water availability, water quality, security, and resilience. The course is organized into 15 sequential modules. The lectures will be augmented by weekly assign...

Water System Adaptation To Hydrological Changes: Module 3, Consequences of Prolonged Drought on Urban Water System Resilience: Case Study from Las Vegas, Nevada, USA

EPA Science Inventory

This course focuses on water system adaptation to short-term and long-term climate and hydrologic stressors that affect water availability, water quality, security, and resilience. The course is organized into 15 sequential modules. The lectures will be augmented by weekly assign...

Water System Adaptations To Hydrological Changes: Module 4, Water Quality Response to Land-use and Precipitation Changes : Case Study of Ohio River Valley, USA

EPA Science Inventory

This course focuses on water system adaptation to short-term and long-term climate and hydrologic stressors that affect water availability, water quality, security, and resilience. The course is organized into 15 sequential modules. The lectures will be augmented by weekly assign...

[Relationship between muscle activity and kinematics of the lower extremity in slow motions of squats in humans].

PubMed

Khorievin, V I; Horkovenko, A V; Vereshchaka, I V

2013-01-01

Squatting can be performed on ankle strategy when ankle joint is flexed more than a hip joint and on hip strategy when large changes occur at the hip joint. The relationships between changes ofjoint angles and electromyogram (EMG) of the leg muscles were studied in five healthy men during squatting that was performed at the ankle and hip strategies with a slow changes in the knee angle of 40 and 60 degrees. It is established that at ankle strategy the ankle muscles were activated ahead of joint angle changes and shifting the center of pressure (CT) on stabilographic platform, whereas activation of the thigh muscles began simultaneously with the change of the joint angles, showing the clear adaptation in successive trials and a linear relationships between the static EMG component and the angle changes of the ankle joint. In the case of hip strategy of squatting the thigh muscles were activated simultaneously with the change in the joint angles and the displacement of CT, whereas the ankle muscles were activated later than the thigh muscles, especially the muscle tibialis anterior, showing some adaptations in consecutive attempts. At the ankle strategy the EMG amplitude was greatest in thigh muscles, reproducing contour of changes in joint angles, whereas the ankle muscles were activated only slightly during changes of joint angles. In the case of hip strategy dominated the EMG amplitude of the muscle tibialis anterior, which was activated when driving down the trunk and fixation of the joint angles that was accompanied by a slight coactivation of the calf muscles with the step-like increase in the amplitude of the EMG of the thigh muscles. Choice of leg muscles to start the squatting on both strategies occurred without a definite pattern, which may indicate the existence of a wide range of options for muscle activity in a single strategy.

Enhanced secure 4-D modulation space optical multi-carrier system based on joint constellation and Stokes vector scrambling.

PubMed

Liu, Bo; Zhang, Lijia; Xin, Xiangjun

2018-03-19

This paper proposes and demonstrates an enhanced secure 4-D modulation optical generalized filter bank multi-carrier (GFBMC) system based on joint constellation and Stokes vector scrambling. The constellation and Stokes vectors are scrambled by using different scrambling parameters. A multi-scroll Chua's circuit map is adopted as the chaotic model. Large secure key space can be obtained due to the multi-scroll attractors and independent operability of subcarriers. A 40.32Gb/s encrypted optical GFBMC signal with 128 parallel subcarriers is successfully demonstrated in the experiment. The results show good resistance against the illegal receiver and indicate a potential way for the future optical multi-carrier system.

Experimental study on direct adaptive control of a PUMA 560 industrial robot

NASA Technical Reports Server (NTRS)

Seraji, H.; Lee, T.; Delpech, M.

1990-01-01

The implementation and experimental validation of a direct adaptive control scheme on a PUMA 560 industrial robot is discussed. The design theory for direct adaptive control of manipulators is outlined and the test facility and software are described. Results are presented from the experiments on the simultaneous control of all of the six joint angles and control of the end-effector position and orientation of the robot. Also, the possible applications of the direct adaptive control scheme are considered.

Slanted joint axes of the stick insect antenna: an adaptation to tactile acuity

NASA Astrophysics Data System (ADS)

Mujagic, Samir; Krause, André F.; Dürr, Volker

2007-04-01

Like many flightless, obligatory walking insects, the stick insect Carausius morosus makes intensive use of active antennal movements for tactile near range exploration and orientation. The antennal joints of C. morosus have a peculiar oblique and non-orthogonal joint axis arrangement. Moreover, this arrangement is known to differ from that in crickets (Ensifera), locusts (Caelifera) and cockroaches (Blattodea), all of which have an orthogonal joint axis arrangement. Our hypothesis was that the situation found in C. morosus represents an important evolutionary trait of the order of stick and leaf insects (Phasmatodea). If this was true, it should be common to other species of the Phasmatodea. The objective of this comparative study was to resolve this question. We have measured the joint axis orientation of the head scape and scape pedicel joints along with other parameters that affect the tactile efficiency of the antenna. The obtained result was a complete kinematic description of the antenna. This was used to determine the size and location of kinematic out-of-reach zones, which are indicators of tactile acuity. We show that the oblique and non-orthogonal arrangement is common to eight species from six sub-families indicating that it is a synapomorphic character of the Euphasmatodea. This character can improve tactile acuity compared to the situation in crickets, locusts and cockroaches. Finally, because molecular data of a recent study indicate that the Phasmatodea may have evolved as flightless, obligatory walkers, we argue that the antennal joint axis arrangement of the Euphasmatodea reflects an evolutionary adaptation to tactile near range exploration during terrestrial locomotion.

Individualized Health Incentive Program Modules for Physically Disabled Students in Grades Kindergarten Through Twelve.

ERIC Educational Resources Information Center

Reggio, Kathryn D.

Individualized health incentive program modules were developed for students having severe physical disabilities. Their needs fell into these categories: lack of function of the involuntary nervous system; paralysis or lack of feeling; bracing or confinement to a wheelchair; muscular weakness; arm and joint immobility; prosthetic limbs; brittle…

75 FR 19673 - Petition for Exemption From the Vehicle Theft Prevention Standard; Saab

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-15

... module (BCM), passive entry passive start module (PEPS), intrusion/inclination sensor, an immobilizer... must be performed by communication between the PEPS and the BCM jointly with the UID (key fob... Saab 9-3, has been designed to enhance the functionality and theft protection provided by Saab's first...

The Influence of PV Module Materials and Design on Solder Joint Thermal Fatigue Durability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bosco, Nick; Silverman, Timothy J.; Kurtz, Sarah

Finite element model (FEM) simulations have been performed to elucidate the effect of flat plate photovoltaic (PV) module materials and design on PbSn eutectic solder joint thermal fatigue durability. The statistical method of Latin Hypercube sampling was employed to investigate the sensitivity of simulated damage to each input variable. Variables of laminate material properties and their thicknesses were investigated. Using analysis of variance, we determined that the rate of solder fatigue was most sensitive to solder layer thickness, with copper ribbon and silicon thickness being the next two most sensitive variables. By simulating both accelerated thermal cycles (ATCs) and PVmore » cell temperature histories through two characteristic days of service, we determined that the acceleration factor between the ATC and outdoor service was independent of the variables sampled in this study. This result implies that an ATC test will represent a similar time of outdoor exposure for a wide range of module designs. This is an encouraging result for the standard ATC that must be universally applied across all modules.« less

ASTP crewmen in Soyuz orbital module mock-up during training session at JSC

NASA Technical Reports Server (NTRS)

1975-01-01

An interior view of the Soyuz orbital module mock-up in bldg 35 during Apollo Soyuz Test Project (ASTP) joint crew training at JSC. The ASTP crewmen are Astronaut Vance D. Brand (on left), command module pilot of the American ASTP prime crew; and Cosmonaut Valeriy N. Kubasov, engineer on the Soviet ASTP first (prime) crew. The training session simulated activities on the second day in Earth orbit.

Holder for rotating glass body

DOEpatents

Kolleck, Floyd W.

1978-04-04

A device is provided for holding and centering a rotating glass body such as a rod or tube. The device includes a tubular tip holder which may be held in a lathe chuck. The device can utilize a variety of centering tips each adapted for a particular configuration, such as a glass O-ring joint or semi-ball joint.

An adaptive coupling strategy for joint inversions that use petrophysical information as constraints

NASA Astrophysics Data System (ADS)

Heincke, Björn; Jegen, Marion; Moorkamp, Max; Hobbs, Richard W.; Chen, Jin

2017-01-01

Joint inversion strategies for geophysical data have become increasingly popular as they allow for the efficient combination of complementary information from different data sets. The algorithm used for the joint inversion needs to be flexible in its description of the subsurface so as to be able to handle the diverse nature of the data. Hence, joint inversion schemes are needed that 1) adequately balance data from the different methods, 2) have stable convergence behavior, 3) consider the different resolution power of the methods used and 4) link the parameter models in a way that they are suited for a wide range of applications. Here, we combine active source seismic P-wave tomography, gravity and magnetotelluric (MT) data in a petrophysical joint inversion that accounts for these issues. Data from the different methods are inverted separately but are linked through constraints accounting for parameter relationships. An advantage of performing the inversions separately is that no relative weighting between the data sets is required. To avoid perturbing the convergence behavior of the inversions by the coupling, the strengths of the constraints are readjusted at each iteration. The criterion we use to control the adaption of the coupling strengths is based on variations in the objective functions of the individual inversions from one to the next iteration. Adaption of the coupling strengths makes the joint inversion scheme also applicable to subsurface conditions, where assumed relationships are not valid everywhere, because the individual inversions decouple if it is not possible to reach adequately low data misfits for the made assumptions. In addition, the coupling constraints depend on the relative resolutions of the methods, which leads to an improved convergence behavior of the joint inversion. Another benefit of the proposed scheme is that structural information can easily be incorporated in the petrophysical joint inversion (no additional terms are added in the objective functions) by using mutually controlled structural weights for the smoothing constraints. We test our scheme using data generated from a synthetic 2-D sub-basalt model. We observe that the adaption of the coupling strengths makes the convergence of the inversions very robust (data misfits of all methods are close to the target misfits) and that final results are always close to the true models independent of the parameter choices. Finally, the scheme is applied on real data sets from the Faroe-Shetland Basin to image a basaltic sequence and underlying structures. The presence of a borehole and a 3-D reflection seismic survey in this region allows direct comparison and, hence, evaluate the quality of the joint inversion results. The results from joint inversion are more consistent with results from other studies than the ones from the corresponding individual inversions and the shape of the basaltic sequence is better resolved. However, due to the limited resolution of the individual methods used it was not possible to resolve structures underneath the basalt in detail, indicating that additional geophysical information (e.g. CSEM, reflection onsets) needs to be included.

"China Today" Module Teachers' National Attitude and Their Implementation of Informal and Nonformal Education under "One Country & Two Systems"

ERIC Educational Resources Information Center

Tak-sang, Dick Yau

2011-01-01

Background: Prior to the 1984 Sino-British Joint Declaration, the civic education were characterized by denationalization and depoliticization. After the Joint Declaration, many of the conflicts emerged between the national interests advocated by the nationalistic camp and the Hong Kong interests promoted by the Liberal camp in the newly…

Student perspectives on the development and evaluation of a joint international education to promote employability in Europe.

PubMed

Craig, Claire; Piškur, Barbara

2012-01-01

This article presents a student evaluation of a joint international education developed as part of a European project which sought to equip health care practitioners with the skills to support employability of individuals furthest removed from the labour market, disadvantaged on account of age, gender, migration or ethnicity. Thirty eight students out of the forty one students that participated in the pilot of four modules (NL, UK, SE, DE) returned completed digital questionnaires (92.6% response rate). The study is descriptive by nature. A questionnaire was used to collect the data from students. Additionally students attending the module in the UK also took part in a series of qualitative interviews which sought to explore their experiences in more detail. These were recorded, transcribed and analyzed. Students reported that joint education facilitates competence development. The competencies they identified (Information Communications Technology) were recognised as being key to enhancing employability of disadvantaged groups. The joint international education exemplified by EEE4all offers one model of how to build a responsive international curriculum to ensure that the workforce of the future is well placed to meet the needs of this changing world.

Novel biological strategies for treatment of wear particle-induced periprosthetic osteolysis of orthopaedic implants for joint replacement

PubMed Central

Goodman, S. B.; Gibon, E.; Pajarinen, J.; Lin, T.-H.; Keeney, M.; Ren, P.-G.; Nich, C.; Yao, Z.; Egashira, K.; Yang, F.; Konttinen, Y. T.

2014-01-01

Wear particles and by-products from joint replacements and other orthopaedic implants may result in a local chronic inflammatory and foreign body reaction. This may lead to persistent synovitis resulting in joint pain and swelling, periprosthetic osteolysis, implant loosening and pathologic fracture. Strategies to modulate the adverse effects of wear debris may improve the function and longevity of joint replacements and other orthopaedic implants, potentially delaying or avoiding complex revision surgical procedures. Three novel biological strategies to mitigate the chronic inflammatory reaction to orthopaedic wear particles are reported. These include (i) interference with systemic macrophage trafficking to the local implant site, (ii) modulation of macrophages from an M1 (pro-inflammatory) to an M2 (anti-inflammatory, pro-tissue healing) phenotype in the periprosthetic tissues, and (iii) local inhibition of the transcription factor nuclear factor kappa B (NF-κB) by delivery of an NF-κB decoy oligodeoxynucleotide, thereby interfering with the production of pro-inflammatory mediators. These three approaches have been shown to be viable strategies for mitigating the undesirable effects of wear particles in preclinical studies. Targeted local delivery of specific biologics may potentially extend the lifetime of orthopaedic implants. PMID:24478281

Water System Adaptation To Hydrological Changes: Module 7, Adaptation Principles and Considerations

EPA Science Inventory

This course will introduce students to the fundamental principles of water system adaptation to hydrological changes, with emphasis on data analysis and interpretation, technical planning, and computational modeling. Starting with real-world scenarios and adaptation needs, the co...

CSIR Contribution to Defining Adaptive Capacity in the Context of Environmental Change

DTIC Science & Technology

2016-01-31

of transboundary water cooperation in the Nile Basin, presentation at the Horn of Africa Water Security Workshop, jointly hosted by the USGS...Nortje and Marius Claassen CSIR PO Box 395 Pretoria 0001, South Africa Date: 31 January 2016 Defining Adaptive Capacity in the...supports CSIR and ERDC research in adaptation to water -related impacts of climate change. The grant supports a comparison of historic human responses to

Potentiating mGluR5 function with a positive allosteric modulator enhances adaptive learning.

PubMed

Xu, Jian; Zhu, Yongling; Kraniotis, Stephen; He, Qionger; Marshall, John J; Nomura, Toshihiro; Stauffer, Shaun R; Lindsley, Craig W; Conn, P Jeffrey; Contractor, Anis

2013-07-18

Metabotropic glutamate receptor 5 (mGluR5) plays important roles in modulating neural activity and plasticity and has been associated with several neuropathological disorders. Previous work has shown that genetic ablation or pharmacological inhibition of mGluR5 disrupts fear extinction and spatial reversal learning, suggesting that mGluR5 signaling is required for different forms of adaptive learning. Here, we tested whether ADX47273, a selective positive allosteric modulator (PAM) of mGluR5, can enhance adaptive learning in mice. We found that systemic administration of the ADX47273 enhanced reversal learning in the Morris Water Maze, an adaptive task. In addition, we found that ADX47273 had no effect on single-session and multi-session extinction, but administration of ADX47273 after a single retrieval trial enhanced subsequent fear extinction learning. Together these results demonstrate a role for mGluR5 signaling in adaptive learning, and suggest that mGluR5 PAMs represent a viable strategy for treatment of maladaptive learning and for improving behavioral flexibility.

Potentiating mGluR5 function with a positive allosteric modulator enhances adaptive learning

PubMed Central

Xu, Jian; Zhu, Yongling; Kraniotis, Stephen; He, Qionger; Marshall, John J.; Nomura, Toshihiro; Stauffer, Shaun R.; Lindsley, Craig W.; Conn, P. Jeffrey; Contractor, Anis

2013-01-01

Metabotropic glutamate receptor 5 (mGluR5) plays important roles in modulating neural activity and plasticity and has been associated with several neuropathological disorders. Previous work has shown that genetic ablation or pharmacological inhibition of mGluR5 disrupts fear extinction and spatial reversal learning, suggesting that mGluR5 signaling is required for different forms of adaptive learning. Here, we tested whether ADX47273, a selective positive allosteric modulator (PAM) of mGluR5, can enhance adaptive learning in mice. We found that systemic administration of the ADX47273 enhanced reversal learning in the Morris Water Maze, an adaptive task. In addition, we found that ADX47273 had no effect on single-session and multi-session extinction, but administration of ADX47273 after a single retrieval trial enhanced subsequent fear extinction learning. Together these results demonstrate a role for mGluR5 signaling in adaptive learning, and suggest that mGluR5 PAMs represent a viable strategy for treatment of maladaptive learning and for improving behavioral flexibility. PMID:23869026

Survey of adaptive image coding techniques

NASA Technical Reports Server (NTRS)

Habibi, A.

1977-01-01

The general problem of image data compression is discussed briefly with attention given to the use of Karhunen-Loeve transforms, suboptimal systems, and block quantization. A survey is then conducted encompassing the four categories of adaptive systems: (1) adaptive transform coding (adaptive sampling, adaptive quantization, etc.), (2) adaptive predictive coding (adaptive delta modulation, adaptive DPCM encoding, etc.), (3) adaptive cluster coding (blob algorithms and the multispectral cluster coding technique), and (4) adaptive entropy coding.

A new class of energy based control laws for revolute robot arms - Tracking control, robustness enhancement and adaptive control

NASA Technical Reports Server (NTRS)

Wen, John T.; Kreutz, Kenneth; Bayard, David S.

1988-01-01

A class of joint-level control laws for all-revolute robot arms is introduced. The analysis is similar to the recently proposed energy Liapunov function approach except that the closed-loop potential function is shaped in accordance with the underlying joint space topology. By using energy Liapunov functions with the modified potential energy, a much simpler analysis can be used to show closed-loop global asymptotic stability and local exponential stability. When Coulomb and viscous friction and model parameter errors are present, a sliding-mode-like modification of the control law is proposed to add a robustness-enhancing outer loop. Adaptive control is also addressed within the same framework. A linear-in-the-parameters formulation is adopted, and globally asymptotically stable adaptive control laws are derived by replacing the model parameters in the nonadaptive control laws by their estimates.

Generation of Adaptive Gait Patterns for Quadruped Robot with CPG Network including Motor Dynamic Model

NASA Astrophysics Data System (ADS)

Son, Yurak; Kamano, Takuya; Yasuno, Takashi; Suzuki, Takayuki; Harada, Hironobu

This paper describes the generation of adaptive gait patterns using new Central Pattern Generators (CPGs) including motor dynamic models for a quadruped robot under various environment. The CPGs act as the flexible oscillators of the joints and make the desired angle of the joints. The CPGs are mutually connected each other, and the sets of their coupling parameters are adjusted by genetic algorithm so that the quadruped robot can realize the stable and adequate gait patterns. As a result of generation, the suitable CPG networks for not only a walking straight gait pattern but also rotation gait patterns are obtained. Experimental results demonstrate that the proposed CPG networks are effective to automatically adjust the adaptive gait patterns for the tested quadruped robot under various environment. Furthermore, the target tracking control based on image processing is achieved by combining the generated gait patterns.

Reading aloud: does previous trial history modulate the joint effects of stimulus quality and word frequency?

PubMed

O'Malley, Shannon; Besner, Derek

2013-07-01

No one would argue with the proposition that how we process events in the world is strongly affected by our experience. Nonetheless, recent experience (e.g., from the previous trial) is typically not considered in the analysis of timed cognitive performance in the laboratory. Masson and Kliegl (2013) reported that, in the context of the lexical decision task, the nature of the previous trial strongly modulates the joint effects of word frequency and stimulus quality-a joint effect that is widely reported to be additive when averaged over trial history. In particular, their analysis suggests there may be no genuine additivity of these factors. Here we extended this line of investigation by reanalyzing data reported by O'Malley and Besner (2008) in which subjects read words and nonwords aloud, with word frequency and stimulus quality as manipulated factors. These factors are additive on reaction time in the standard analysis of variance. Contrary to Masson and Kliegl's finding for lexical decision, when previous trial history is taken into consideration, these 2 factors still do not interact. This suggests that, at least in the context of reading aloud, previous trial does not modulate how the effects of these 2 factors combine. Some implications are briefly noted. PsycINFO Database Record (c) 2013 APA, all rights reserved.

CRISPR adaptive immune systems of Archaea

PubMed Central

Vestergaard, Gisle; Garrett, Roger A; Shah, Shiraz A

2014-01-01

CRISPR adaptive immune systems were analyzed for all available completed genomes of archaea, which included representatives of each of the main archaeal phyla. Initially, all proteins encoded within, and proximal to, CRISPR-cas loci were clustered and analyzed using a profile–profile approach. Then cas genes were assigned to gene cassettes and to functional modules for adaptation and interference. CRISPR systems were then classified primarily on the basis of their concatenated Cas protein sequences and gene synteny of the interference modules. With few exceptions, they could be assigned to the universal Type I or Type III systems. For Type I, subtypes I-A, I-B, and I-D dominate but the data support the division of subtype I-B into two subtypes, designated I-B and I-G. About 70% of the Type III systems fall into the universal subtypes III-A and III-B but the remainder, some of which are phyla-specific, diverge significantly in Cas protein sequences, and/or gene synteny, and they are classified separately. Furthermore, a few CRISPR systems that could not be assigned to Type I or Type III are categorized as variant systems. Criteria are presented for assigning newly sequenced archaeal CRISPR systems to the different subtypes. Several accessory proteins were identified that show a specific gene linkage, especially to Type III interference modules, and these may be cofunctional with the CRISPR systems. Evidence is presented for extensive exchange having occurred between adaptation and interference modules of different archaeal CRISPR systems, indicating the wide compatibility of the functionally diverse interference complexes with the relatively conserved adaptation modules. PMID:24531374

Evolutionary adaptations for the temporal processing of natural sounds by the anuran peripheral auditory system

PubMed Central

Schrode, Katrina M.; Bee, Mark A.

2015-01-01

ABSTRACT Sensory systems function most efficiently when processing natural stimuli, such as vocalizations, and it is thought that this reflects evolutionary adaptation. Among the best-described examples of evolutionary adaptation in the auditory system are the frequent matches between spectral tuning in both the peripheral and central auditory systems of anurans (frogs and toads) and the frequency spectra of conspecific calls. Tuning to the temporal properties of conspecific calls is less well established, and in anurans has so far been documented only in the central auditory system. Using auditory-evoked potentials, we asked whether there are species-specific or sex-specific adaptations of the auditory systems of gray treefrogs (Hyla chrysoscelis) and green treefrogs (H. cinerea) to the temporal modulations present in conspecific calls. Modulation rate transfer functions (MRTFs) constructed from auditory steady-state responses revealed that each species was more sensitive than the other to the modulation rates typical of conspecific advertisement calls. In addition, auditory brainstem responses (ABRs) to paired clicks indicated relatively better temporal resolution in green treefrogs, which could represent an adaptation to the faster modulation rates present in the calls of this species. MRTFs and recovery of ABRs to paired clicks were generally similar between the sexes, and we found no evidence that males were more sensitive than females to the temporal modulation patterns characteristic of the aggressive calls used in male–male competition. Together, our results suggest that efficient processing of the temporal properties of behaviorally relevant sounds begins at potentially very early stages of the anuran auditory system that include the periphery. PMID:25617467

Human-like Compliance for Dexterous Robot Hands

NASA Technical Reports Server (NTRS)

Jau, Bruno M.

1995-01-01

This paper describes the Active Electromechanical Compliance (AEC) system that was developed for the Jau-JPL anthropomorphic robot. The AEC system imitates the functionality of the human muscle's secondary function, which is to control the joint's stiffness: AEC is implemented through servo controlling the joint drive train's stiffness. The control strategy, controlling compliant joints in teleoperation, is described. It enables automatic hybrid position and force control through utilizing sensory feedback from joint and compliance sensors. This compliant control strategy is adaptable for autonomous robot control as well. Active compliance enables dual arm manipulations, human-like soft grasping by the robot hand, and opens the way to many new robotics applications.

Optical joint transform correlation on the DMD. [deformable mirror device

NASA Technical Reports Server (NTRS)

Knopp, Jerome; Juday, Richard D.

1989-01-01

Initial experimental investigation of the deformable mirror device (DMD) in a joint optical transform correlation is reported. The inverted cloverleaf version of the DMD, in which form the DMD is phase-mostly but of limited phase range, is used. Binarized joint Fourier transforms were calculated for similar and dissimilar objects and written onto the DMD. Inverse Fourier transform was done in a diffraction order for which the DMD shows phase-mostly modulation. Matched test objects produced sharp correlation, distinct objects did not. Further studies are warranted and they are outlined.

Communication system analysis for manned space flight

NASA Technical Reports Server (NTRS)

Schilling, D. L.

1978-01-01

The development of adaptive delta modulators capable of digitizing a video signal is summarized. The delta modulator encoder accepts a 4 MHz black and white composite video signal or a color video signal and encodes it into a stream of binary digits at a rate which can be adjusted from 8 Mb/s to 24 Mb/s. The output bit rate is determined by the user and alters the quality of the video picture. The digital signal is decoded using the adaptive delta modulator decoder to reconstruct the picture.

A process model for the heat-affected zone microstructure evolution in duplex stainless steel weldments: Part II. Application to electron beam welding

NASA Astrophysics Data System (ADS)

Hemmer, H.; Grong, Ø.; Klokkehaug, S.

2000-03-01

In the present investigation, a process model for electron beam (EB) welding of different grades of duplex stainless steels (i.e. SAF 2205 and 2507) has been developed. A number of attractive features are built into the original finite element code, including (1) a separate module for prediction of the penetration depth and distribution of the heat source into the plate, (2) adaptive refinement of the three-dimensional (3-D) element mesh for quick and reliable solution of the differential heat flow equation, and (3) special subroutines for calculation of the heat-affected zone (HAZ) microstructure evolution. The process model has been validated by comparison with experimental data obtained from in situ thermocouple measurements and optical microscope examinations. Subsequently, its aptness to alloy design and optimization of welding conditions for duplex stainless steels is illustrated in different numerical examples and case studies pertaining to EB welding of tubular joints.

Advanced driver assistance system: Road sign identification using VIAPIX system and a correlation technique

NASA Astrophysics Data System (ADS)

Ouerhani, Y.; Alfalou, A.; Desthieux, M.; Brosseau, C.

2017-02-01

We present a three-step approach based on the commercial VIAPIX® module for road traffic sign recognition and identification. Firstly, detection in a scene of all objects having characteristics of traffic signs is performed. This is followed by a first-level recognition based on correlation which consists in making a comparison between each detected object with a set of reference images of a database. Finally, a second level of identification allows us to confirm or correct the previous identification. In this study, we perform a correlation-based analysis by combining and adapting the Vander Lugt correlator with the nonlinear joint transformation correlator (JTC). Of particular significance, this approach permits to make a reliable decision on road traffic sign identification. We further discuss a robust scheme allowing us to track a detected road traffic sign in a video sequence for the purpose of increasing the decision performance of our system. This approach can have broad practical applications in the maintenance and rehabilitation of transportation infrastructure, or for drive assistance.

Modular microfluidic system for biological sample preparation

DOEpatents

Rose, Klint A.; Mariella, Jr., Raymond P.; Bailey, Christopher G.; Ness, Kevin Dean

2015-09-29

A reconfigurable modular microfluidic system for preparation of a biological sample including a series of reconfigurable modules for automated sample preparation adapted to selectively include a) a microfluidic acoustic focusing filter module, b) a dielectrophoresis bacteria filter module, c) a dielectrophoresis virus filter module, d) an isotachophoresis nucleic acid filter module, e) a lyses module, and f) an isotachophoresis-based nucleic acid filter.

Specificity of the Human Frequency Following Response for Carrier and Modulation Frequency Assessed Using Adaptation.

PubMed

Gockel, Hedwig E; Krugliak, Alexandra; Plack, Christopher J; Carlyon, Robert P

2015-12-01

The frequency following response (FFR) is a scalp-recorded measure of phase-locked brainstem activity to stimulus-related periodicities. Three experiments investigated the specificity of the FFR for carrier and modulation frequency using adaptation. FFR waveforms evoked by alternating-polarity stimuli were averaged for each polarity and added, to enhance envelope, or subtracted, to enhance temporal fine structure information. The first experiment investigated peristimulus adaptation of the FFR for pure and complex tones as a function of stimulus frequency and fundamental frequency (F0). It showed more adaptation of the FFR in response to sounds with higher frequencies or F0s than to sounds with lower frequency or F0s. The second experiment investigated tuning to modulation rate in the FFR. The FFR to a complex tone with a modulation rate of 213 Hz was not reduced more by an adaptor that had the same modulation rate than by an adaptor with a different modulation rate (90 or 504 Hz), thus providing no evidence that the FFR originates mainly from neurons that respond selectively to the modulation rate of the stimulus. The third experiment investigated tuning to audio frequency in the FFR using pure tones. An adaptor that had the same frequency as the target (213 or 504 Hz) did not generally reduce the FFR to the target more than an adaptor that differed in frequency (by 1.24 octaves). Thus, there was no evidence that the FFR originated mainly from neurons tuned to the frequency of the target. Instead, the results are consistent with the suggestion that the FFR for low-frequency pure tones at medium to high levels mainly originates from neurons tuned to higher frequencies. Implications for the use and interpretation of the FFR are discussed.

Electronic health record analysis via deep poisson factor models

DOE Office of Scientific and Technical Information (OSTI.GOV)

Henao, Ricardo; Lu, James T.; Lucas, Joseph E.

Electronic Health Record (EHR) phenotyping utilizes patient data captured through normal medical practice, to identify features that may represent computational medical phenotypes. These features may be used to identify at-risk patients and improve prediction of patient morbidity and mortality. We present a novel deep multi-modality architecture for EHR analysis (applicable to joint analysis of multiple forms of EHR data), based on Poisson Factor Analysis (PFA) modules. Each modality, composed of observed counts, is represented as a Poisson distribution, parameterized in terms of hidden binary units. In-formation from different modalities is shared via a deep hierarchy of common hidden units. Activationmore » of these binary units occurs with probability characterized as Bernoulli-Poisson link functions, instead of more traditional logistic link functions. In addition, we demon-strate that PFA modules can be adapted to discriminative modalities. To compute model parameters, we derive efficient Markov Chain Monte Carlo (MCMC) inference that scales efficiently, with significant computational gains when compared to related models based on logistic link functions. To explore the utility of these models, we apply them to a subset of patients from the Duke-Durham patient cohort. We identified a cohort of over 12,000 patients with Type 2 Diabetes Mellitus (T2DM) based on diagnosis codes and laboratory tests out of our patient population of over 240,000. Examining the common hidden units uniting the PFA modules, we identify patient features that represent medical concepts. Experiments indicate that our learned features are better able to predict mortality and morbidity than clinical features identified previously in a large-scale clinical trial.« less

Electronic health record analysis via deep poisson factor models

DOE PAGES

Henao, Ricardo; Lu, James T.; Lucas, Joseph E.; ...

2016-01-01

Electronic Health Record (EHR) phenotyping utilizes patient data captured through normal medical practice, to identify features that may represent computational medical phenotypes. These features may be used to identify at-risk patients and improve prediction of patient morbidity and mortality. We present a novel deep multi-modality architecture for EHR analysis (applicable to joint analysis of multiple forms of EHR data), based on Poisson Factor Analysis (PFA) modules. Each modality, composed of observed counts, is represented as a Poisson distribution, parameterized in terms of hidden binary units. In-formation from different modalities is shared via a deep hierarchy of common hidden units. Activationmore » of these binary units occurs with probability characterized as Bernoulli-Poisson link functions, instead of more traditional logistic link functions. In addition, we demon-strate that PFA modules can be adapted to discriminative modalities. To compute model parameters, we derive efficient Markov Chain Monte Carlo (MCMC) inference that scales efficiently, with significant computational gains when compared to related models based on logistic link functions. To explore the utility of these models, we apply them to a subset of patients from the Duke-Durham patient cohort. We identified a cohort of over 12,000 patients with Type 2 Diabetes Mellitus (T2DM) based on diagnosis codes and laboratory tests out of our patient population of over 240,000. Examining the common hidden units uniting the PFA modules, we identify patient features that represent medical concepts. Experiments indicate that our learned features are better able to predict mortality and morbidity than clinical features identified previously in a large-scale clinical trial.« less

Water System Adaptation to Hydrological Changes: Module 1, Introduction to Water System Adaptation

EPA Science Inventory

Contemporary water management requires resilience, the ability to meet ever increasing water needs, and capacity to adapt to abrupt or transient changes in water quality and availability. For this purpose, effective adaptation to extreme hydrological events (e.g. intense storms, ...

More pain, more gain: Blocking the opioid system boosts adaptive cognitive control.

PubMed

van Steenbergen, Henk; Weissman, Daniel H; Stein, Dan J; Malcolm-Smith, Susan; van Honk, Jack

2017-06-01

The ability to adaptively increase cognitive control in response to cognitive challenges is crucial for goal-directed behavior. Recent findings suggest that aversive arousal triggers adaptive increases of control, but the neurochemical mechanisms underlying these effects remain unclear. Given the known contributions of the opioid system to hedonic states, we investigated whether blocking this system increases adaptive control modulations. To do so, we conducted a double-blind, placebo-controlled psychopharmacological study (n=52 females) involving a Stroop-like task. Specifically, we assessed the effect of naltrexone, an opioid blocker most selective to the mu-opioid system, on two measures of adaptive control that are thought to depend differentially on aversive arousal: post-error slowing and conflict adaptation. Consistent with our hypothesis, relative to placebo, naltrexone increased post-error slowing without influencing conflict adaptation. This finding not only supports the view that aversive arousal triggers adaptive control but also reveals a novel role for the opioid system in modulating such effects. Copyright © 2017 Elsevier Ltd. All rights reserved.

A dual-learning paradigm can simultaneously train multiple characteristics of walking

PubMed Central

Toliver, Alexis; Bastian, Amy J.

2016-01-01

Impairments in human motor patterns are complex: what is often observed as a single global deficit (e.g., limping when walking) is actually the sum of several distinct abnormalities. Motor adaptation can be useful to teach patients more normal motor patterns, yet conventional training paradigms focus on individual features of a movement, leaving others unaddressed. It is known that under certain conditions, distinct movement components can be simultaneously adapted without interference. These previous “dual-learning” studies focused solely on short, planar reaching movements, yet it is unknown whether these findings can generalize to a more complex behavior like walking. Here we asked whether a dual-learning paradigm, incorporating two distinct motor adaptation tasks, can be used to simultaneously train multiple components of the walking pattern. We developed a joint-angle learning task that provided biased visual feedback of sagittal joint angles to increase peak knee or hip flexion during the swing phase of walking. Healthy, young participants performed this task independently or concurrently with another locomotor adaptation task, split-belt treadmill adaptation, where subjects adapted their step length symmetry. We found that participants were able to successfully adapt both components of the walking pattern simultaneously, without interference, and at the same rate as adapting either component independently. This leads us to the interesting possibility that combining rehabilitation modalities within a single training session could be used to help alleviate multiple deficits at once in patients with complex gait impairments. PMID:26961100

Adaptive eLearning modules for cytopathology education: A review and approach.

PubMed

Samulski, T Danielle; La, Teresa; Wu, Roseann I

2016-11-01

Clinical training imposes time and resource constraints on educators and learners, making it difficult to provide and absorb meaningful instruction. Additionally, innovative and personalized education has become an expectation of adult learners. Fortunately, the development of web-based educational tools provides a possible solution to these challenges. Within this review, we introduce the utility of adaptive eLearning platforms in pathology education. In addition to a review of the current literature, we provide the reader with a suggested approach for module creation, as well as a critical assessment of an available platform, based on our experience in creating adaptive eLearning modules for teaching basic concepts in gynecologic cytopathology. Diagn. Cytopathol. 2016;44:944-951. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Neural controller for adaptive movements with unforeseen payloads.

PubMed

Kuperstein, M; Wang, J

1990-01-01

A theory and computer simulation of a neural controller that learns to move and position a link carrying an unforeseen payload accurately are presented. The neural controller learns adaptive dynamic control from its own experience. It does not use information about link mass, link length, or direction of gravity, and it uses only indirect uncalibrated information about payload and actuator limits. Its average positioning accuracy across a large range of payloads after learning is 3% of the positioning range. This neural controller can be used as a basis for coordinating any number of sensory inputs with limbs of any number of joints. The feedforward nature of control allows parallel implementation in real time across multiple joints.

ASTP crewmen in Docking Module trainer during training session at JSC

NASA Technical Reports Server (NTRS)

1975-01-01

An interior view of the Docking Module trainer in bldg 35 during Apollo Soyuz Test Project (ASTP) joint crew training at JSC. Astronaut Thomas P. Stafford, commander of the American ASTP prime crew, is on the right. The other crewman is Cosmonaut Aleksey A. Leonov, commander of the Soviet ASTP prime crew. The training session simulated activities on the second day in Earth orbit. The Docking Module is designed to link the Apollo and Soyuz spacecraft.

An interdigit signalling centre instructs coordinate phalanx-joint formation governed by 5′Hoxd–Gli3 antagonism

PubMed Central

Huang, Bau-Lin; Trofka, Anna; Furusawa, Aki; Norrie, Jacqueline L.; Rabinowitz, Adam H.; Vokes, Steven A.; Mark Taketo, M.; Zakany, Jozsef; Mackem, Susan

2016-01-01

The number of phalanges and joints are key features of digit ‘identity' and are central to limb functionality and evolutionary adaptation. Prior chick work indicated that digit phalanges and their associated joints arise in a different manner than the more sparsely jointed long bones, and their identity is regulated by differential signalling from adjacent interdigits. Currently, there is no genetic evidence for this model, and the molecular mechanisms governing digit joint specification remain poorly understood. Using genetic approaches in mouse, here we show that functional 5′Hoxd–Gli3 antagonism acts indirectly, through Bmp signalling from the interdigital mesenchyme, to regulate specification of joint progenitors, which arise in conjunction with phalangeal precursors at the digit tip. Phalanx number, although co-regulated, can be uncoupled from joint specification. We propose that 5′Hoxd genes and Gli3 are part of an interdigital signalling centre that sets net Bmp signalling levels from different interdigits to coordinately regulate phalanx and joint formation. PMID:27713395

A Novel Modulation Classification Approach Using Gabor Filter Network

PubMed Central

Ghauri, Sajjad Ahmed; Qureshi, Ijaz Mansoor; Cheema, Tanveer Ahmed; Malik, Aqdas Naveed

2014-01-01

A Gabor filter network based approach is used for feature extraction and classification of digital modulated signals by adaptively tuning the parameters of Gabor filter network. Modulation classification of digitally modulated signals is done under the influence of additive white Gaussian noise (AWGN). The modulations considered for the classification purpose are PSK 2 to 64, FSK 2 to 64, and QAM 4 to 64. The Gabor filter network uses the network structure of two layers; the first layer which is input layer constitutes the adaptive feature extraction part and the second layer constitutes the signal classification part. The Gabor atom parameters are tuned using Delta rule and updating of weights of Gabor filter using least mean square (LMS) algorithm. The simulation results show that proposed novel modulation classification algorithm has high classification accuracy at low signal to noise ratio (SNR) on AWGN channel. PMID:25126603

National Training Course. Emergency Medical Technician. Paramedic. Instructor's Lesson Plans. Module IX. Musculoskeletal.

ERIC Educational Resources Information Center

National Highway Traffic Safety Administration (DOT), Washington, DC.

This instructor's lesson plan guide on the musculoskeletal system is one of fifteen modules designed for use in the training of emergency medical technicians (paramedics). Five units of study are presented: (1) the major bones, joints, and muscles of the body; (2) patient assessment of a musculoskeletal injury; (3) pathophysiology and management…

Water System Adaptation To Hydrological Changes: Module 12, Models and Tools for Stormwater and Wastewater System Adaptation

EPA Science Inventory

This course will introduce students to the fundamental principles of water system adaptation to hydrological changes, with emphasis on data analysis and interpretation, technical planning, and computational modeling. Starting with real-world scenarios and adaptation needs, the co...

Adaptively loaded IM/DD optical OFDM based on set-partitioned QAM formats.

PubMed

Zhao, Jian; Chen, Lian-Kuan

2017-04-17

We investigate the constellation design and symbol error rate (SER) of set-partitioned (SP) quadrature amplitude modulation (QAM) formats. Based on the SER analysis, we derive the adaptive bit and power loading algorithm for SP QAM based intensity-modulation direct-detection (IM/DD) orthogonal frequency division multiplexing (OFDM). We experimentally show that the proposed system significantly outperforms the conventional adaptively-loaded IM/DD OFDM and can increase the data rate from 36 Gbit/s to 42 Gbit/s in the presence of severe dispersion-induced spectral nulls after 40-km single-mode fiber. It is also shown that the adaptive algorithm greatly enhances the tolerance to fiber nonlinearity and allows for more power budget.

Texture-adaptive hyperspectral video acquisition system with a spatial light modulator

NASA Astrophysics Data System (ADS)

Fang, Xiaojing; Feng, Jiao; Wang, Yongjin

2014-10-01

We present a new hybrid camera system based on spatial light modulator (SLM) to capture texture-adaptive high-resolution hyperspectral video. The hybrid camera system records a hyperspectral video with low spatial resolution using a gray camera and a high-spatial resolution video using a RGB camera. The hyperspectral video is subsampled by the SLM. The subsampled points can be adaptively selected according to the texture characteristic of the scene by combining with digital imaging analysis and computational processing. In this paper, we propose an adaptive sampling method utilizing texture segmentation and wavelet transform (WT). We also demonstrate the effectiveness of the sampled pattern on the SLM with the proposed method.

How visual short-term memory maintenance modulates subsequent visual aftereffects.

PubMed

Saad, Elyana; Silvanto, Juha

2013-05-01

Prolonged viewing of a visual stimulus can result in sensory adaptation, giving rise to perceptual phenomena such as the tilt aftereffect (TAE). However, it is not known if short-term memory maintenance induces such effects. We examined how visual short-term memory (VSTM) maintenance modulates the strength of the TAE induced by subsequent visual adaptation. We reasoned that if VSTM maintenance induces aftereffects on subsequent encoding of visual information, then it should either enhance or reduce the TAE induced by a subsequent visual adapter, depending on the congruency of the memory cue and the adapter. Our results were consistent with this hypothesis and thus indicate that the effects of VSTM maintenance can outlast the maintenance period.

Performance trade-off in an adaptive IEEE 802.11ad waveform design for a joint automotive radar and communication system.

DOT National Transportation Integrated Search

2017-05-01

The IEEE 802.11ad waveform can be used for automotive radar by exploiting the Golay complementary sequences in the preamble of a frame. The performance of radar, however, is limited by the preamble structure. In this paper, we propose an adaptive pre...

Walking boot assembly

NASA Technical Reports Server (NTRS)

Vykukal, H. C.; Chambers, A. B.; Stjohn, R. H. (Inventor)

1977-01-01

A walking boot assembly particularly suited for use with a positively pressurized spacesuit is presented. A bootie adapted to be secured to the foot of a wearer, an hermetically sealed boot for receiving the bootie having a walking sole, an inner sole, and an upper portion adapted to be attached to an ankle joint of a spacesuit, are also described.

Pilot Clinical Application of an Adaptive Robotic System for Young Children with Autism

ERIC Educational Resources Information Center

Bekele, Esubalew; Crittendon, Julie A.; Swanson, Amy; Sarkar, Nilanjan; Warren, Zachary E.

2014-01-01

It has been argued that clinical applications of advanced technology may hold promise for addressing impairments associated with autism spectrum disorders. This pilot feasibility study evaluated the application of a novel adaptive robot-mediated system capable of both administering and automatically adjusting joint attention prompts to a small…

FPGA-based rate-adaptive LDPC-coded modulation for the next generation of optical communication systems.

PubMed

Zou, Ding; Djordjevic, Ivan B

2016-09-05

In this paper, we propose a rate-adaptive FEC scheme based on LDPC codes together with its software reconfigurable unified FPGA architecture. By FPGA emulation, we demonstrate that the proposed class of rate-adaptive LDPC codes based on shortening with an overhead from 25% to 42.9% provides a coding gain ranging from 13.08 dB to 14.28 dB at a post-FEC BER of 10^-15 for BPSK transmission. In addition, the proposed rate-adaptive LDPC coding combined with higher-order modulations have been demonstrated including QPSK, 8-QAM, 16-QAM, 32-QAM, and 64-QAM, which covers a wide range of signal-to-noise ratios. Furthermore, we apply the unequal error protection by employing different LDPC codes on different bits in 16-QAM and 64-QAM, which results in additional 0.5dB gain compared to conventional LDPC coded modulation with the same code rate of corresponding LDPC code.

Task-induced frequency modulation features for brain-computer interfacing.

PubMed

Jayaram, Vinay; Hohmann, Matthias; Just, Jennifer; Schölkopf, Bernhard; Grosse-Wentrup, Moritz

2017-10-01

Task-induced amplitude modulation of neural oscillations is routinely used in brain-computer interfaces (BCIs) for decoding subjects' intents, and underlies some of the most robust and common methods in the field, such as common spatial patterns and Riemannian geometry. While there has been some interest in phase-related features for classification, both techniques usually presuppose that the frequencies of neural oscillations remain stable across various tasks. We investigate here whether features based on task-induced modulation of the frequency of neural oscillations enable decoding of subjects' intents with an accuracy comparable to task-induced amplitude modulation. We compare cross-validated classification accuracies using the amplitude and frequency modulated features, as well as a joint feature space, across subjects in various paradigms and pre-processing conditions. We show results with a motor imagery task, a cognitive task, and also preliminary results in patients with amyotrophic lateral sclerosis (ALS), as well as using common spatial patterns and Laplacian filtering. The frequency features alone do not significantly out-perform traditional amplitude modulation features, and in some cases perform significantly worse. However, across both tasks and pre-processing in healthy subjects the joint space significantly out-performs either the frequency or amplitude features alone. This result only does not hold for ALS patients, for whom the dataset is of insufficient size to draw any statistically significant conclusions. Task-induced frequency modulation is robust and straight forward to compute, and increases performance when added to standard amplitude modulation features across paradigms. This allows more information to be extracted from the EEG signal cheaply and can be used throughout the field of BCIs.

Building the Army: A Strategic Review of a Complex Problem

DTIC Science & Technology

2013-03-01

is more than a true chameleon that slightly adapts its characteristics to the given case.”2 One cannot predict the shifting colors/characteristics...Strategy (NMS) of the United States of America calling for a flexible, agile, and adaptive Joint Force capable of full spectrum operations that...or may not be remedied, one can safely certify TAA as a robust and proven process based solely on the adaptable and tailorable Army that exists

JPRS Report, Science & Technology, Europe

DTIC Science & Technology

1992-02-18

could penetrate the ceramic layer. At the time, the Essen researchers were unable to present any proof of the obvious assumption that microfine pores...carbon fiber tubes and titanium frame joints that are very light and strong. The manufacturing system and experiments are installed as modules on...study also view the manufacturing technol- ogies and jointing techniques for active cooling with an integrated cooling tube system as unavailable—pure

Dynamic modeling and optimal joint torque coordination of advanced robotic systems

NASA Astrophysics Data System (ADS)

Kang, Hee-Jun

The development is documented of an efficient dynamic modeling algorithm and the subsequent optimal joint input load coordination of advanced robotic systems for industrial application. A closed-form dynamic modeling algorithm for the general closed-chain robotic linkage systems is presented. The algorithm is based on the transfer of system dependence from a set of open chain Lagrangian coordinates to any desired system generalized coordinate set of the closed-chain. Three different techniques for evaluation of the kinematic closed chain constraints allow the representation of the dynamic modeling parameters in terms of system generalized coordinates and have no restriction with regard to kinematic redundancy. The total computational requirement of the closed-chain system model is largely dependent on the computation required for the dynamic model of an open kinematic chain. In order to improve computational efficiency, modification of an existing open-chain KIC based dynamic formulation is made by the introduction of the generalized augmented body concept. This algorithm allows a 44 pct. computational saving over the current optimized one (O(N4), 5995 when N = 6). As means of resolving redundancies in advanced robotic systems, local joint torque optimization is applied for effectively using actuator power while avoiding joint torque limits. The stability problem in local joint torque optimization schemes is eliminated by using fictitious dissipating forces which act in the necessary null space. The performance index representing the global torque norm is shown to be satisfactory. In addition, the resulting joint motion trajectory becomes conservative, after a transient stage, for repetitive cyclic end-effector trajectories. The effectiveness of the null space damping method is shown. The modular robot, which is built of well defined structural modules from a finite-size inventory and is controlled by one general computer system, is another class of evolving, highly versatile, advanced robotic systems. Therefore, finally, a module based dynamic modeling algorithm is presented for the dynamic coordination of such reconfigurable modular robotic systems. A user interactive module based manipulator analysis program (MBMAP) has been coded in C language running on 4D/70 Silicon Graphics.

KSC - APOLLO-SOYUZ TEST PROJECT (ASTP) COMMAND SERVICE MODULE (CSM) - KSC

NASA Image and Video Library

1974-09-08

S74-32049 (8 Sept. 1974) --- The Apollo Command Module for the Apollo-Soyuz Test Project mission goes through receiving, inspection and checkout procedures in the Manned Spacecraft Operations Building at the Kennedy Space Center. The spacecraft had just arrived by air from the Rockwell International plant at Downey, California. The Apollo spacecraft (Command Module, Service Module and Docking Module), with astronauts Thomas P. Stafford, Vance D. Brand and Donald K. Slayton aboard, will dock in Earth orbit with a Soviet Soyuz spacecraft during the joint U.S.-USSR ASTP flight scheduled for July 1975. The Soviet and American crews will visit one another?s spacecraft.

Descending and Local Network Interactions Control Adaptive Locomotion

DTIC Science & Technology

2014-12-04

segment). The thorax-coxa ( ThC ) joint swings dramatically in the front leg, but hardly moves at all in the middle and hind legs. These observations...changes in the three degree of freedom thorax-coxa joint ( ThC ) (Fig. 1). Indeed we were able to describe which of the three degrees of freedom were...these actions are distinct. The T1 leg relies heavily on actions of the second and third degree of freedom of the ThC joint ( ThC 2 and ThC3) whereas in

Spinal GABA-B receptor modulates neutrophil recruitment to the knee joint in zymosan-induced arthritis.

PubMed

Bassi, Gabriel S; do C Malvar, David; Cunha, Thiago M; Cunha, Fernando Q; Kanashiro, Alexandre

2016-08-01

Recent studies have demonstrated that the central nervous system controls inflammatory responses by activating complex efferent neuroimmune pathways. The present study was designed to evaluate the role that central gamma-aminobutyric acid type B (GABA-B) receptor plays in neutrophil migration in a murine model of zymosan-induced arthritis by using different pharmacological tools. We observed that intrathecal administration of baclofen, a selective GABA-B agonist, exacerbated the inflammatory response in the knee after zymosan administration characterized by an increase in the neutrophil recruitment and knee joint edema, whereas saclofen, a GABA-B antagonist, exerted the opposite effect. Intrathecal pretreatment of the animals with SB203580 (an inhibitor of p38 mitogen-activated protein kinase) blocked the pro-inflammatory effect of baclofen. On the other hand, systemic administration of guanethidine, a sympatholytic drug that inhibits catecholamine release, and nadolol, a beta-adrenergic receptor antagonist, reversed the effect of saclofen. Moreover, saclofen suppressed the release of the pro-inflammatory cytokines into the knee joint (ELISA) and pain-related behaviors (open field test). Since the anti-inflammatory effect of saclofen depends on the sympathetic nervous system integrity, we observed that isoproterenol, a beta-adrenergic receptor agonist, mimics the central GABA-B blockade decreasing knee joint neutrophil recruitment. Together, these results demonstrate that the pharmacological manipulation of spinal GABAergic transmission aids control of neutrophil migration to the inflamed joint by modulating the activation of the knee joint-innervating sympathetic terminal fibers through a mechanism dependent on peripheral beta-adrenergic receptors and central components, such as p38 MAPK.

Multisite EPR oximetry from multiple quadrature harmonics.

PubMed

Ahmad, R; Som, S; Johnson, D H; Zweier, J L; Kuppusamy, P; Potter, L C

2012-01-01

Multisite continuous wave (CW) electron paramagnetic resonance (EPR) oximetry using multiple quadrature field modulation harmonics is presented. First, a recently developed digital receiver is used to extract multiple harmonics of field modulated projection data. Second, a forward model is presented that relates the projection data to unknown parameters, including linewidth at each site. Third, a maximum likelihood estimator of unknown parameters is reported using an iterative algorithm capable of jointly processing multiple quadrature harmonics. The data modeling and processing are applicable for parametric lineshapes under nonsaturating conditions. Joint processing of multiple harmonics leads to 2-3-fold acceleration of EPR data acquisition. For demonstration in two spatial dimensions, both simulations and phantom studies on an L-band system are reported. Copyright © 2011 Elsevier Inc. All rights reserved.

What Factors Promote Student Resilience on a Level 1 Distance Learning Module?

ERIC Educational Resources Information Center

Simons, Joan; Beaumont, Kythe; Holland, Lesley

2018-01-01

Resilience is understood to be the ability to adapt positively in the face of adversity. In relation to new students on a distance learning module, this can mean how they adapt and make sense of the demands of their chosen study to enable them to persist in their studies. This article reports a small-scale study involving semi-structured telephone…

Proximal and distal muscle fatigue differentially affect movement coordination

PubMed Central

Cowley, Jeffrey C.

2017-01-01

Muscle fatigue can cause people to change their movement patterns and these changes could contribute to acute or overuse injuries. However, these effects depend on which muscles are fatigued. The purpose of this study was to determine the differential effects of proximal and distal upper extremity muscle fatigue on repetitive movements. Fourteen subjects completed a repetitive ratcheting task before and after a fatigue protocol on separate days. The fatigue protocol either fatigued the proximal (shoulder flexor) or distal (finger flexor) muscles. Pre/Post changes in trunk, shoulder, elbow, and wrist kinematics were compared to determine how proximal and distal fatigue affected multi-joint movement patterns and variability. Proximal fatigue caused a significant increase (7°, p < 0.005) in trunk lean and velocity, reduced humeral elevation (11°, p < 0.005), and increased elbow flexion (4°, p < 0.01). In contrast, distal fatigue caused small but significant changes in trunk angles (2°, p < 0.05), increased velocity of wrench movement relative to the hand (17°/s, p < 0.001), and earlier wrist extension (4%, p < 0.005). Movement variability increased at proximal joints but not distal joints after both fatigue protocols (p < 0.05). Varying movements at proximal joints may help people adapt to fatigue at either proximal or distal joints. The identified differences between proximal and distal muscle fatigue adaptations could facilitate risk assessment of occupational tasks. PMID:28235005

Lower extremity joint coupling variability during gait in young adults with and without chronic ankle instability.

PubMed

Lilley, Thomas; Herb, Christopher C; Hart, Joseph; Hertel, Jay

2018-06-01

Chronic ankle instability (CAI) is a condition resulting from a lateral ankle sprain. Shank-rearfoot joint-coupling variability differences have been found in CAI patients; however, joint-coupling variability (VCV) of the ankle and proximal joints has not been explored. Our purpose was to analyse VCV in adults with and without CAI during gait. Four joint-coupling pairs were analysed: knee sagittal-ankle sagittal, knee sagittal-ankle frontal, hip frontal-ankle sagittal and hip frontal-ankle frontal. Twenty-seven adults participated (CAI:n = 13, Control:n = 14). Lower extremity kinematics were collected during walking (4.83 km/h) and jogging (9.66 km/h). Vector-coding was used to assess the stride-to-stride variability of four coupling pairs. During walking, CAI patients exhibited higher VCV than healthy controls for knee sagittal-ankle frontal in latter parts of stance thru mid-swing. When jogging, CAI patients demonstrated lower VCV with specific differences occurring across various intervals of gait. The increased knee sagittal-ankle frontal VCV in CAI patients during walking may indicate an adaptation to deal with the previously identified decrease in variability in transverse plane shank and frontal plane rearfoot coupling during walking; while the decreased ankle-knee and ankle-hip VCV identified in CAI patients during jogging may represent a more rigid, less adaptable sensorimotor system ambulating at a faster speed.

KSC01padig234

NASA Image and Video Library

2001-06-21

KENNEDY SPACE CENTER, Fla. -- After a journey of more than 8 hours from the Vehicle Assembly Building, Space Shuttle Atlantis sits on Launch Pad 39B. At left is the Rotating Service Structure, which will roll on its axis to enclose the Shuttle until launch. Towering above the Fixed Service Structure next to it is the 80-foot tall lightning mast that provides protection from lightning strikes. On the right is the elevated water tank with a capacity of 300,000 gallons. Part of the Sound Suppression Water System, the water in the tank is released just before ignition of the orbiter’s three main engines and twin solid rocket boosters and flow through parallel 7-foot-diameter pipes to the pad area. The Shuttle is targeted for launch no earlier than July 12 on mission STS-104, the 10th flight to the International Space Station. The payload on the 11-day mission is the Joint Airlock Module, which will allow astronauts and cosmonauts in residence on the Station to perform future spacewalks without the presence of a Space Shuttle. The module, which comprises a crew lock and an equipment lock, will be connected to the starboard (right) side of Node 1 Unity. Atlantis will also carry oxygen and nitrogen storage tanks, vital to operation of the Joint Airlock, on a Spacelab Logistics Double Pallet in the payload bay. The tanks, to be installed on the perimeter of the Joint Module during the mission’s spacewalks, will support future spacewalk operations and experiments plus augment the resupply system for the Station’s Service Module

Igniter adapter-to-igniter chamber deflection test

NASA Technical Reports Server (NTRS)

Cook, M.

1990-01-01

Testing was performed to determine the maximum RSRM igniter adapter-to-igniter chamber joint deflection at the crown of the inner joint primary seal. The deflection data was gathered to support igniter inner joint gasket resiliency predictions which led to launch commit criteria temperature determinations. The proximity (deflection) gage holes for the first test (Test No. 1) were incorrectly located; therefore, the test was declared a non-test. Prior to Test No. 2, test article configuration was modified with the correct proximity gage locations. Deflection data were successfully acquired during Test No. 2. However, the proximity gage deflection measurements were adversely affected by temperature increases. Deflections measured after the temperature rise at the proximity gages were considered unreliable. An analysis was performed to predict the maximum deflections based on the reliable data measured before the detectable temperature rise. Deflections to the primary seal crown location were adjusted to correspond to the time of maximum expected operating pressure (2,159 psi) to account for proximity gage bias, and to account for maximum attach and special bolt relaxation. The maximum joint deflection for the igniter inner joint at the crown of the primary seal, accounting for all significant correction factors, was 0.0031 in. (3.1 mil). Since the predicted (0.003 in.) and tested maximum deflection values were sufficiently close, the launch commit criteria was not changed as a result of this test. Data from this test should be used to determine if the igniter inner joint gasket seals are capable of maintaining sealing capability at a joint displacement of (1.4) x (0.0031 in.) = 0.00434 inches. Additional testing should be performed to increase the database on igniter deflections and address launch commit criteria temperatures.

Reduction of hip joint reaction force via medio-lateral foot center of pressure manipulation in bilateral hip osteoarthritis patients.

PubMed

Solomonow-Avnon, Deborah; Haim, Amir; Levin, Daniel; Elboim-Gabyzon, Michal; Rozen, Nimrod; Peled, Eli; Wolf, Alon

2016-10-01

Loading/excessive loading of the hip joint has been linked to onset and progression of hip osteoarthritis. Footwear-generated biomechanical manipulation in the frontal plane has been previously shown in a cohort of healthy subjects to cause a specific gait adaption when the foot center of pressure trajectory was shifted medially, which thereby significantly reduced hip joint reaction force. The objective of the present study was to validate these results in a cohort of female bilateral hip osteoarthritis patients. Sixteen patients underwent gait analysis while using a footworn biomechanical device, allowing controlled foot center of pressure manipulation, in three para-sagittal configurations: medial, lateral, and neutral. Hip osteoarthritis patients exhibited similar results to those observed in healthy subjects in that a medial center of pressure led to an increase in inter-maleolar distance while step width (i.e., distance between right and left foot center of pressure) remained constant. This adaptation, which we speculate subjects adopt to maintain base of support, was associated with significantly greater hip abduction, significantly decreased hip adduction moment, and significantly reduced joint reaction force compared to the neutral and lateral configurations. Recommendations for treatment of hip osteoarthritis emphasize reduction of loads on the pathological joint(s) during daily activities and especially in gait. Our results show that a medially deviated center of pressure causes a reduction in hip joint reaction force. The present study does not prove, but rather suggests, clinical significance, and further investigation is required to assess clinical implications. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1762-1771, 2016. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

Apollo Spacecraft 012 Command/Service Module being moved to Operations bldg

NASA Technical Reports Server (NTRS)

1967-01-01

Transfer of Apollo Spacecraft 012 Command/Service Module for mating to the Saturn Lunar Module Adapter No. 05 in the Manned Spacecraft Operations bldg. S/C 012 will be flown on the Apollo/Saturn 204 mission.

Targeting Metabolic Plasticity in Breast Cancer Cells via Mitochondrial Complex I Modulation

PubMed Central

Xu, Qijin; Biener-Ramanujan, Eva; Yang, Wei; Ramanujan, V Krishnan

2016-01-01

Purpose Heterogeneity commonly observed in clinical tumors stems both from the genetic diversity as well as from the differential metabolic adaptation of multiple cancer types during their struggle to maintain uncontrolled proliferation and invasion in vivo. This study aims to identify a potential metabolic window of such adaptation in aggressive human breast cancer cell lines. Methods With a multidisciplinary approach using high resolution imaging, cell metabolism assays, proteomic profiling and animal models of human tumor xenografts and via clinically-relevant, pharmacological approach for modulating mitochondrial complex I function in human breast cancer cell lines, we report a novel route to target metabolic plasticity in human breast cancer cells. Results By a systematic modulation of mitochondrial function and by mitigating metabolic switch phenotype in aggressive human breast cancer cells, we demonstrate that the resulting metabolic adaptation signatures can predictably decrease tumorigenic potential in vivo. Proteomic profiling of the metabolic adaptation in these cells further revealed novel protein-pathway interactograms highlighting the importance of antioxidant machinery in the observed metabolic adaptation. Conclusions Improved metabolic adaptation potential in aggressive human breast cancer cells contribute to improving mitochondrial function and reducing metabolic switch phenotype –which may be vital for targeting primary tumor growth in vivo. PMID:25677747

The estimated mechanical advantage of the prosimian ankle joint musculature, and implications for locomotor adaptation.

PubMed

Goto, Ryosuke; Kumakura, Hiroo

2013-05-01

In this study we compared the power arm lengths and mechanical advantages attributed to 12 lower leg muscles across three prosimian species. The origins and insertions of the lower leg muscles in Garnett's galago, the ring-tailed lemur, and the slow loris were quantified and correlated with positional behaviour. The ankle joint of the galago has a speed-oriented mechanical system, in contrast to that of the slow loris, which exhibits more power-oriented mechanics. The lemur ankle joint exhibited intermediate power arm lengths and an intermediate mechanical advantage relative to the other primates. This result suggests that the mechanical differences in the ankle between the galago and the lemur, taxa that exhibit similar locomotory repertoires, reflect a difference in the kinematics and kinetics of leaping (i.e. generalised vs. specialised leapers). In contrast to leaping primates, lorises have developed a more power-oriented mechanical system as a foot adaptation for positional behaviours such as bridging or cantilevering in their arboreal habitat. © 2013 Anatomical Society.

[The effect of magnetotherapy on the immunobiochemical indices of subjects with diseases of the periodontal tissues and joints].

PubMed

Samoĭlovich, V A

1999-01-01

Kept under medical surveillance in a health resort setting were 52 patients with disorders of the parodontium and large joints. All patients were given a complex therapy involving dietotherapy, therapeutic exercise, hydrotherapy, mud-treatment. Those patients having parodontium diseases were also prescribed topical treatment (chloride-sodium mouth baths and mud applications to the gingiva area). The main group subjects were also exposed to VMF using the unit for low-frequency therapy "Gradient-1". Laboratory means were also made use of, as a complex of biochemical tests characterizing changes in lipid metabolism. The level of the natural bodily resistance was determined by nitroblue tetrazolium test (NBT-test). The condition of the parodontium was evaluated by the Loë-Silness index. Adaptive reactions were studied by the lymphocytes-to-segmented neutrophils ratio. Adoption of therapy involving physiobalneofactors in patients with afflictions of the parodontium tissues and large joints makes for development of favourable in prognostic respect adaptive reactions.

Water System Adaptation To Hydrological Changes: Module 14, Life Cycle Analysis (LCA) and Prioritization Tools in Water System Adaptation

EPA Science Inventory

This course will introduce students to the fundamental principles of water system adaptation to hydrological changes, with emphasis on data analysis and interpretation, technical planning, and computational modeling. Starting with real-world scenarios and adaptation needs, the co...

Water System Adaptation to Hydrological Changes: Module 10, Basic Principles of Incorporating Adaptation Science into Hydrologic Planning and Design

EPA Science Inventory

This course will introduce students to the fundamental principles of water system adaptation to hydrological changes, with emphasis on data analysis and interpretation, technical planning, and computational modeling. Starting with real-world scenarios and adaptation needs, the co...

Water System Adaptation To Hydrological Changes: Module 5, Water Quality and Infrastructure Response to Rapid Urbanization: Adaptation Case Study in China

EPA Science Inventory

This course will introduce students to the fundamental principles of water system adaptation to hydrological changes, with emphasis on data analysis and interpretation, technical planning, and computational modeling. Starting with real-world scenarios and adaptation needs, the co...

Natural frequency identification of smart washer by using adaptive observer

NASA Astrophysics Data System (ADS)

Ito, Hitoshi; Okugawa, Masayuki

2014-04-01

Bolted joints are used in many machines/structures and some of them have been loosened during long time use, and unluckily these bolt loosening may cause a great accident of machines/structures system. These bolted joint, especially in important places, are main object of maintenance inspection. Maintenance inspection with human- involvement is desired to be improved owing to time-consuming, labor-intensive and high-cost. By remote and full automation monitoring of the bolt loosening, constantly monitoring of bolted joint is achieved. In order to detect loosening of bolted joints without human-involvement, applying a structural health monitoring technique and smart structures/materials concept is the key objective. In this study, a new method of bolt loosening detection by adopting a smart washer has been proposed, and the basic detection principle was discussed with numerical analysis about frequency equation of the system, was confirmed experimentally. The smart washer used in this study is in cantilever type with piezoelectric material, which adds the washer the self-sensing and actuation function. The principle used to detect the loosening of the bolts is a method of a bolt loosening detection noted that the natural frequency of a smart washer system is decreasing by the change of the bolt tightening axial tension. The feature of this proposed method is achieving to identify the natural frequency at current condition on demand by adopting the self-sensing and actuation function and system identification algorithm for varying the natural frequency depending the bolt tightening axial tension. A novel bolt loosening detection method by adopting adaptive observer is proposed in this paper. The numerical simulations are performed to verify the possibility of the adaptive observer-based loosening detection. Improvement of the detection accuracy for a bolt loosening is confirmed by adopting initial parameter and variable adaptive gain by numerical simulation.

Objective Assessment of Joint Stiffness: A Clinically Oriented Hardware and Software Device with an Application to the Shoulder Joint.

PubMed

McQuade, Kevin; Price, Robert; Liu, Nelson; Ciol, Marcia A

2012-08-30

Examination of articular joints is largely based on subjective assessment of the "end-feel" of the joint in response to manually applied forces at different joint orientations. This technical report aims to describe the development of an objective method to examine joints in general, with specific application to the shoulder, and suitable for clinical use. We adapted existing hardware and developed laptop-based software to objectively record the force/displacement behavior of the glenohumeral joint during three common manual joint examination tests with the arm in six positions. An electromagnetic tracking system recorded three-dimensional positions of sensors attached to a clinician examiner and a patient. A hand-held force transducer recorded manually applied translational forces. The force and joint displacement were time-synchronized and the joint stiffness was calculated as a quantitative representation of the joint "end-feel." A methodology and specific system checks were developed to enhance clinical testing reproducibility and precision. The device and testing protocol were tested on 31 subjects (15 with healthy shoulders, and 16 with a variety of shoulder impairments). Results describe the stiffness responses, and demonstrate the feasibility of using the device and methods in clinical settings.

Evolutionary adaptations for the temporal processing of natural sounds by the anuran peripheral auditory system.

PubMed

Schrode, Katrina M; Bee, Mark A

2015-03-01

Sensory systems function most efficiently when processing natural stimuli, such as vocalizations, and it is thought that this reflects evolutionary adaptation. Among the best-described examples of evolutionary adaptation in the auditory system are the frequent matches between spectral tuning in both the peripheral and central auditory systems of anurans (frogs and toads) and the frequency spectra of conspecific calls. Tuning to the temporal properties of conspecific calls is less well established, and in anurans has so far been documented only in the central auditory system. Using auditory-evoked potentials, we asked whether there are species-specific or sex-specific adaptations of the auditory systems of gray treefrogs (Hyla chrysoscelis) and green treefrogs (H. cinerea) to the temporal modulations present in conspecific calls. Modulation rate transfer functions (MRTFs) constructed from auditory steady-state responses revealed that each species was more sensitive than the other to the modulation rates typical of conspecific advertisement calls. In addition, auditory brainstem responses (ABRs) to paired clicks indicated relatively better temporal resolution in green treefrogs, which could represent an adaptation to the faster modulation rates present in the calls of this species. MRTFs and recovery of ABRs to paired clicks were generally similar between the sexes, and we found no evidence that males were more sensitive than females to the temporal modulation patterns characteristic of the aggressive calls used in male-male competition. Together, our results suggest that efficient processing of the temporal properties of behaviorally relevant sounds begins at potentially very early stages of the anuran auditory system that include the periphery. © 2015. Published by The Company of Biologists Ltd.

Variation in the modal parameters of space structures

NASA Technical Reports Server (NTRS)

Crawley, Edward F.; Barlow, Mark S.; Van Schoor, Marthinus C.; Bicos, Andrew S.

1992-01-01

An analytic and experimental study of gravity and suspension influences on space structural test articles is presented. A modular test article including deployable, erectable, and rotary modules was assembled in three one- and two-dimensional structures. The two deployable modules utilized cable diagonal bracing rather than rigid cross members; within a bay of one of the deployable modules, the cable preload was adjustable. A friction lock was used on the alpha joint to either allow or prohibit rotary motion. Suspension systems with plunge fundamentals of 1, 2, and 5 Hz were used for ground testing to evaluate the influences of suspension stiffness. Assembly and reassembly testing was performed, as was testing on two separate shipsets at two test sites. Trends and statistical variances in modal parameters are presented as a function of force amplitude, joint preload, reassembly, shipset and suspension. Linear finite element modeling of each structure provided analytical results for 0-g unsuspended and 1-g suspended models, which are correlated with the analytical model.

Control of joint motion simulators for biomechanical research

NASA Technical Reports Server (NTRS)

Colbaugh, R.; Glass, K.

1992-01-01

The authors present a hierarchical adaptive algorithm for controlling upper extremity human joint motion simulators. A joint motion simulator is a computer-controlled, electromechanical system which permits the application of forces to the tendons of a human cadaver specimen in such a way that the cadaver joint under study achieves a desired motion in a physiologic manner. The proposed control scheme does not require knowledge of the cadaver specimen dynamic model, and solves on-line the indeterminate problem which arises because human joints typically possess more actuators than degrees of freedom. Computer simulation results are given for an elbow/forearm system and wrist/hand system under hierarchical control. The results demonstrate that any desired normal joint motion can be accurately tracked with the proposed algorithm. These simulation results indicate that the controller resolved the indeterminate problem redundancy in a physiologic manner, and show that the control scheme was robust to parameter uncertainty and to sensor noise.

Blind adaptive equalization of polarization-switched QPSK modulation.

PubMed

Millar, David S; Savory, Seb J

2011-04-25

Coherent detection in combination with digital signal processing has recently enabled significant progress in the capacity of optical communications systems. This improvement has enabled detection of optimum constellations for optical signals in four dimensions. In this paper, we propose and investigate an algorithm for the blind adaptive equalization of one such modulation format: polarization-switched quaternary phase shift keying (PS-QPSK). The proposed algorithm, which includes both blind initialization and adaptation of the equalizer, is found to be insensitive to the input polarization state and demonstrates highly robust convergence in the presence of PDL, DGD and polarization rotation.

Modulations of Foot and Ankle Frontal Kinematics for Breaking and Propulsive Movement Characteristics during Side-Step Cutting with Varying Midsole Thicknesses

PubMed Central

Lin, Yi-Jia; Lee, Shih-Chi; Chang, Chao-Chin; Liu, Tsung-Han

2018-01-01

This study is aimed at determining the effects of midsole thickness on movement characteristic during side cutting movement. Fifteen athletes performed side-step cutting while wearing shoes with varying midsole thicknesses. Temporal-spatial and ground reaction force variables as well as foot and ankle frontal kinematics were used to describe breaking and propulsive movement characteristics and modulation strategies. Regardless of midsole thickness, temporal-spatial variables and breaking and propulsive force during side cutting were statistically unchanged. Significantly greater peaks of ankle inversion and plantarflexion with a thicker sole and greater midtarsal pronation with a thinner sole were observed. Current results demonstrated that hypotheses formed solely based on material testing were insufficient to understand the adaptations in human movement because of the redundancy of the neuromusculoskeletal system. Participants were able to maintain temporal-spatial performance during side cutting while wearing shoes with midsoles of varying thicknesses. Increased pronation for a thinner sole might help reduce the force of impact but might be associated with an increased risk of excessive stress on soft tissue. Increased peak of ankle inversion and plantarflexion for a thicker sole may be unfavorable for the stability of ankle joint. Information provided in human movement testing is crucial for understanding factors associated with movement characteristics and injury and should be considered in the future development of shoe design. PMID:29854000

Secondary Education, 314-340, Modules 8-16.

ERIC Educational Resources Information Center

Toledo Univ., OH. Coll. of Education.

Thirteen learning modules are included in this competency-based secondary education course syllabus, which was adapted from an elementary education course syllabus developed at the College of Education of the University of Toledo for the U.S. Office of Education. Each of the modules contains its title/topic, prerequisite modules, rationale for the…

Joint Attention in Parent-Child Dyads Involving Children with Selective Mutism: A Comparison between Anxious and Typically Developing Children

ERIC Educational Resources Information Center

Nowakowski, Matilda E.; Tasker, Susan L.; Cunningham, Charles E.; McHolm, Angela E.; Edison, Shannon; St. Pierre, Jeff; Boyle, Michael H.; Schmidt, Louis A.

2011-01-01

Although joint attention processes are known to play an important role in adaptive social behavior in typical development, we know little about these processes in clinical child populations. We compared early school age children with selective mutism (SM; n = 19) versus mixed anxiety (MA; n = 18) and community controls (CC; n = 26) on joint…

From Joint Experimentation to Laissez-Faire: Transdisciplinary Innovation Research for the Institutional Strengthening of a Water Users Association in Khorezm, Uzbekistan

ERIC Educational Resources Information Center

Djanibekov, Nodir; Hornidge, Anna-Katharina; Ul-Hassan, Mehmood

2012-01-01

Purpose: This article assesses a participatory action and innovation research experience, in which project researchers, farmers and staff members of a local water users association (WUA) came together to: (a) jointly test and adapt a social mobilization and institutional strengthening approach according to the local context, and by doing so, to…

Experimental joint quantum measurements with minimum uncertainty.

PubMed

Ringbauer, Martin; Biggerstaff, Devon N; Broome, Matthew A; Fedrizzi, Alessandro; Branciard, Cyril; White, Andrew G

2014-01-17

Quantum physics constrains the accuracy of joint measurements of incompatible observables. Here we test tight measurement-uncertainty relations using single photons. We implement two independent, idealized uncertainty-estimation methods, the three-state method and the weak-measurement method, and adapt them to realistic experimental conditions. Exceptional quantum state fidelities of up to 0.999 98(6) allow us to verge upon the fundamental limits of measurement uncertainty.

Automatic joint alignment measurements in pre- and post-operative long leg standing radiographs.

PubMed

Goossen, A; Weber, G M; Dries, S P M

2012-01-01

For diagnosis or treatment assessment of knee joint osteoarthritis it is required to measure bone morphometry from radiographic images. We propose a method for automatic measurement of joint alignment from pre-operative as well as post-operative radiographs. In a two step approach we first detect and segment any implants or other artificial objects within the image. We exploit physical characteristics and avoid prior shape information to cope with the vast amount of implant types. Subsequently, we exploit the implant delineations to adapt the initialization and adaptation phase of a dedicated bone segmentation scheme using deformable template models. Implant and bone contours are fused to derive the final joint segmentation and thus the alignment measurements. We evaluated our method on clinical long leg radiographs and compared both the initialization rate, corresponding to the number of images successfully processed by the proposed algorithm, and the accuracy of the alignment measurement. Ground truth has been generated by an experienced orthopedic surgeon. For comparison a second reader reevaluated the measurements. Experiments on two sets of 70 and 120 digital radiographs show that 92% of the joints could be processed automatically and the derived measurements of the automatic method are comparable to a human reader for pre-operative as well as post-operative images with a typical error of 0.7° and correlations of r = 0.82 to r = 0.99 with the ground truth. The proposed method allows deriving objective measures of joint alignment from clinical radiographs. Its accuracy and precision are on par with a human reader for all evaluated measurements.

Computerized Adaptive Testing Project: Objectives and Requirements.

DTIC Science & Technology

1982-07-01

developing a cqmputerlzed adaptive lwfb system ( CAT ). SiN 0102- LP. Old. "O AM"- S/M "of F.g~ smuuim ftmAYUSN 0 IM ~ A joint-service coordinated effort is In...progress to develop a computerized adaptive testing ( CAT ) system and to evaluate its potential for use in the Military Enlistment Processing Stations...lead laboratory for this effort. This report is intended to serve as a working paper documenting CAT system functional requirements and schedules. It

A Study of Teachers' Paradigms of the "China Today" Module in Hong Kong under One Country and Two Systems

ERIC Educational Resources Information Center

Yau, Dick Tak-sang

2009-01-01

Background: During the period of British colonial rule, the nature of civic education in Hong Kong was characterized as denationalized, depoliticized and decontextualized. The 1984 Sino-British Joint Declaration substantially altered the nature of civic education. The "China Today" module of Liberal Studies (LS) was one of the results…

Development of an Autonomous Broadband Acoustic Scattering System for Remote Characterization of Zooplankton

DTIC Science & Technology

2008-01-01

backscatter at a single narrowband frequency, and some AUVs carry single-frequency sidescan sonars (and this technology has been adapted for gliders), the...broadband acoustic scattering system by adapting existing technology that has been recently developed at WHOI for a monostatic Doppler sonar module...broadband acoustic backscattering system: 1) Modifications to the monostatic Doppler sonar module, recently developed at WHOI for turbulence studies

Mothers' and Fathers' Parenting Styles and Associations with Toddlers' Externalizing, Internalizing, and Adaptive Behaviors

ERIC Educational Resources Information Center

Rinaldi, Christina M.; Howe, Nina

2012-01-01

The two primary objectives of the present study were to (a) investigate mothers' and fathers' reports of their own as well as their partner's parenting styles, and (b) assess how mothers' and fathers' parenting styles uniquely and jointly predicted toddlers' externalizing, internalizing, and adaptive behaviors. Fifty-nine mothers and fathers…

Astronaut Stafford and Cosmonaut Leonov during joint crew training at JSC

NASA Image and Video Library

1975-02-24

S75-21945 (24 Feb. 1975) --- Cosmonaut Aleksey A. Leonov (left) and astronaut Thomas P. Stafford take part in Apollo-Soyuz Test Project joint crew training in Building 35 at NASA's Johnson Space Center. They are commanders of their respective prime crews. The training session simulated the activities of the second day in Earth orbit. Stafford and Leonov are in the Docking Module mock-up.

Regeneration of spine disc and joint cartilages under temporal and space modulated laser radiation

NASA Astrophysics Data System (ADS)

Sobol, E.; Shekhter, A.; Baskov, A.; Baskov, V.; Baum, O.; Borchshenko, I.; Golubev, V.; Guller, A.; Kolyshev, I.; Omeltchenko, A.; Sviridov, A.; Zakharkina, O.

2009-02-01

The effect of laser radiation on the generation of hyaline cartilage in spine disc and joints has been demonstrated. The paper considers physical processes and mechanisms of laser regeneration, presents results of investigations aimed to optimize laser settings and to develop feedback control system for laser reconstruction of spine discs. Possible mechanisms of laser-induced regeneration include: (1) Space and temporary modulated laser beam induces nonhomogeneous and pulse repetitive thermal expansion and stress in the irradiated zone of cartilage. Mechanical effect due to controllable thermal expansion of the tissue and micro and nano gas bubbles formation in the course of the moderate (up to 45-50 oC) heating of the NP activate biological cells (chondrocytes) and promote cartilage regeneration. (2) Nondestructive laser radiation leads to the formation of nano and micro-pores in cartilage matrix. That promotes water permeability and increases the feeding of biological cells. Results provide the scientific and engineering basis for the novel low-invasive laser procedures to be used in orthopedics for the treatment cartilages of spine and joints. The technology and equipment for laser reconstruction of spine discs have been tested first on animals, and then in a clinical trial. Since 2001 the laser reconstruction of intervertebral discs have been performed for 340 patients with chronic symptoms of low back or neck pain who failed to improve with non-operative care. Substantial relief of back pain was obtained in 90% of patients treated who returned to their daily activities. The experiments on reparation of the defects in articular cartilage of the porcine joints under temporal and spase modulated laser radiation have shown promising results.

Recognition of tennis serve performed by a digital player: comparison among polygon, shadow, and stick-figure models.

PubMed

Ida, Hirofumi; Fukuhara, Kazunobu; Ishii, Motonobu

2012-01-01

The objective of this study was to assess the cognitive effect of human character models on the observer's ability to extract relevant information from computer graphics animation of tennis serve motions. Three digital human models (polygon, shadow, and stick-figure) were used to display the computationally simulated serve motions, which were perturbed at the racket-arm by modulating the speed (slower or faster) of one of the joint rotations (wrist, elbow, or shoulder). Twenty-one experienced tennis players and 21 novices made discrimination responses about the modulated joint and also specified the perceived swing speeds on a visual analogue scale. The result showed that the discrimination accuracies of the experienced players were both above and below chance level depending on the modulated joint whereas those of the novices mostly remained at chance or guessing levels. As far as the experienced players were concerned, the polygon model decreased the discrimination accuracy as compared with the stick-figure model. This suggests that the complicated pictorial information may have a distracting effect on the recognition of the observed action. On the other hand, the perceived swing speed of the perturbed motion relative to the control was lower for the stick-figure model than for the polygon model regardless of the skill level. This result suggests that the simplified visual information can bias the perception of the motion speed toward slower. It was also shown that the increasing the joint rotation speed increased the perceived swing speed, although the resulting racket velocity had little correlation with this speed sensation. Collectively, observer's recognition of the motion pattern and perception of the motion speed can be affected by the pictorial information of the human model as well as by the perturbation processing applied to the observed motion.

Comparing Anisotropic Output-Based Grid Adaptation Methods by Decomposition

NASA Technical Reports Server (NTRS)

Park, Michael A.; Loseille, Adrien; Krakos, Joshua A.; Michal, Todd

2015-01-01

Anisotropic grid adaptation is examined by decomposing the steps of flow solution, ad- joint solution, error estimation, metric construction, and simplex grid adaptation. Multiple implementations of each of these steps are evaluated by comparison to each other and expected analytic results when available. For example, grids are adapted to analytic metric fields and grid measures are computed to illustrate the properties of multiple independent implementations of grid adaptation mechanics. Different implementations of each step in the adaptation process can be evaluated in a system where the other components of the adaptive cycle are fixed. Detailed examination of these properties allows comparison of different methods to identify the current state of the art and where further development should be targeted.

Analytical approach to an integrate-and-fire model with spike-triggered adaptation

NASA Astrophysics Data System (ADS)

Schwalger, Tilo; Lindner, Benjamin

2015-12-01

The calculation of the steady-state probability density for multidimensional stochastic systems that do not obey detailed balance is a difficult problem. Here we present the analytical derivation of the stationary joint and various marginal probability densities for a stochastic neuron model with adaptation current. Our approach assumes weak noise but is valid for arbitrary adaptation strength and time scale. The theory predicts several effects of adaptation on the statistics of the membrane potential of a tonically firing neuron: (i) a membrane potential distribution with a convex shape, (ii) a strongly increased probability of hyperpolarized membrane potentials induced by strong and fast adaptation, and (iii) a maximized variability associated with the adaptation current at a finite adaptation time scale.

Joint digital signal processing for superchannel coherent optical communication systems.

PubMed

Liu, Cheng; Pan, Jie; Detwiler, Thomas; Stark, Andrew; Hsueh, Yu-Ting; Chang, Gee-Kung; Ralph, Stephen E

2013-04-08

Ultra-high-speed optical communication systems which can support ≥ 1Tb/s per channel transmission will soon be required to meet the increasing capacity demand. However, 1Tb/s over a single carrier requires either or both a high-level modulation format (i.e. 1024QAM) and a high baud rate. Alternatively, grouping a number of tightly spaced "sub-carriers" to form a terabit superchannel increases channel capacity while minimizing the need for high-level modulation formats and high baud rate, which may allow existing formats, baud rate and components to be exploited. In ideal Nyquist-WDM superchannel systems, optical subcarriers with rectangular spectra are tightly packed at a channel spacing equal to the baud rate, thus achieving the Nyquist bandwidth limit. However, in practical Nyquist-WDM systems, precise electrical or optical control of channel spectra is required to avoid strong inter-channel interference (ICI). Here, we propose and demonstrate a new "super receiver" architecture for practical Nyquist-WDM systems, which jointly detects and demodulates multiple channels simultaneously and mitigates the penalties associated with the limitations of generating ideal Nyquist-WDM spectra. Our receiver-side solution relaxes the filter requirements imposed on the transmitter. Two joint DSP algorithms are developed for linear ICI cancellation and joint carrier-phase recovery. Improved system performance is observed with both experimental and simulation data. Performance analysis under different system configurations is conducted to demonstrate the feasibility and robustness of the proposed joint DSP algorithms.

Residual stresses in a stainless steel - titanium alloy joint made with the explosive technique

NASA Astrophysics Data System (ADS)

Taran, Yu V.; Balagurov, A. M.; Sabirov, B. M.; Evans, A.; Davydov, V.; Venter, A. M.

2012-02-01

Joining of pipes from stainless steel (SS) and titanium (Ti) alloy still experience serious technical problems. Recently, reliable and hermetic joining of SS and Ti pipes has been achieved with the explosive bonding technique in the Russian Federal Nuclear Center. Such adapters are earmarked for use at the future International Linear Collider. The manufactured SS-Ti adapters have excellent mechanical behavior at room and liquid nitrogen temperatures, during high-pressure tests and thermal cycling. We here report the first neutron diffraction investigation of the residual stresses in a SS-Ti adapter on the POLDI instrument at the SINQ spallation source. The strain scanning across the adapter walls into the SS-SS and SS-Ti pipes sections encompassed measurement of the axial, radial and hoop strain components, which were transformed into residual stresses. The full stress information was successfully determined for the three steel pipes involved in the joint. The residual stresses do not exceed 300 MPa in magnitude. All stress components have tensile values close to the adapter internal surface, whilst they are compressive close to the outer surface. The strong incoherent and weak coherent neutron scattering cross-sections of Ti did not allow for the reliable determination of stresses inside the titanic pipe.

Properties of the welded joints of manganese steel made by low-frequency pulsed arc welding

NASA Astrophysics Data System (ADS)

Saraev, Yu. N.; Bezborodov, V. P.; Gladovskii, S. V.; Golikov, N. I.

2017-04-01

The structure, the mechanical properties, the impact toughness, and the fracture mechanisms of the welded joints made of steel 09G2S plates by direct current welding and pulsed arc welding with a modulated arc current in the frequency range 0.25-5.0 Hz are studied. The application of low-frequency pulsed arc welding allowed us to form welded joints with a fine-grained structure in the weld metal and the heat-affected zone and to achieve a higher impact toughness and a longer cyclic fatigue life as compared to the welded joints fabricated by direct current welding. The achieved effect manifests itself over the entire testing range from 20 to-60°C.

Thermal Protection System with Staggered Joints

NASA Technical Reports Server (NTRS)

Simon, Xavier D. (Inventor); Robinson, Michael J. (Inventor); Andrews, Thomas L. (Inventor)

2014-01-01

The thermal protection system disclosed herein is suitable for use with a spacecraft such as a reentry module or vehicle, where the spacecraft has a convex surface to be protected. An embodiment of the thermal protection system includes a plurality of heat resistant panels, each having an outer surface configured for exposure to atmosphere, an inner surface opposite the outer surface and configured for attachment to the convex surface of the spacecraft, and a joint edge defined between the outer surface and the inner surface. The joint edges of adjacent ones of the heat resistant panels are configured to mate with each other to form staggered joints that run between the peak of the convex surface and the base section of the convex surface.

A Wolff in sheep's clothing: trabecular bone adaptation in response to changes in joint loading orientation.

PubMed

Barak, Meir M; Lieberman, Daniel E; Hublin, Jean-Jacques

2011-12-01

This study tests Wolff's law of trabecular bone adaptation by examining if induced changes in joint loading orientation cause corresponding adjustments in trabecular orientation. Two groups of sheep were exercised at a trot, 15 min/day for 34 days on an inclined (7°) or level (0°) treadmills. Incline trotting caused the sheep to extend their tarsal joints by 3-4.5° during peak loading (P<0.01) but has no effect on carpal joint angle (P=0.984). Additionally, tarsal joint angle in the incline group sheep were maintained more extended throughout the day using elevated platform shoes on their forelimbs. A third "sedentary group" group did not run but wore platform shoes throughout the day. As predicted by Wolff's law, trabecular orientation in the distal tibia (tarsal joint) were more obtuse by 2.7 to 4.3° in the incline group compared to the level group; trabecular orientation was not significantly different in the sedentary and level groups. In addition, trabecular orientations in the distal radius (carpal joint) of the sedentary, level and incline groups did not differ between groups, and were aligned almost parallel to the radius long axis, corresponding to the almost straight carpal joint angle at peak loading. Measurements of other trabecular bone parameters revealed additional responses to loading, including significantly higher bone volume fraction (BV/TV), Trabecular number (Tb.N) and trabecular thickness (Tb.Th), lower trabecular spacing (Tb.Sp), and less rod-shaped trabeculae (higher structure model index, SMI) in the exercised than sedentary sheep. Overall, these results demonstrate that trabecular bone dynamically adjusts and realigns itself in very precise relation to changes in peak loading direction, indicating that Wolff's law is not only accurate but also highly sensitive. Copyright © 2011 Elsevier Inc. All rights reserved.

Fundamentals of Adaptive Intelligent Tutoring Systems for Self-Regulated Learning

DTIC Science & Technology

2015-03-01

has 4 fundamental elements: a learner model, a pedagogical (instructional) model, a domain model, and a communication model. Figure 5 shows a...The TUI has been discussed in detail, so now the learner, pedagogical , and domain modules will be reviewed:  Learner module. In addition to...shared states, which are provided to the pedagogical module.  Pedagogical module. The pedagogical module models the instructional techniques

An Approach to Designing Passive Self-Leveling Landing Gear with Application to the Lunar Lander

NASA Technical Reports Server (NTRS)

Rippere, Troy B.; Wiens, Gloria J.

2010-01-01

Once the lunar lander has touched down on the moon problems can occur if the crew module is not level. To mitigate, compliant landing gear provide a solution that would allow the module to be leveled once it has landed on some ground slope. The work presented here uses compliant joints, or flexures, for each leg of the module and optimizes the mechanics of these flexures such that the module can be passively leveled over a range of landing slopes. Preliminary results suggest that for landing on a slope of up to 12 deg the effective slope of the module can be reduced to a maximum of 2.5 deg.

A Module Experimental Process System Development Unit (MEPSDU)

NASA Technical Reports Server (NTRS)

1981-01-01

Subsequent to the design review, a series of tests was conducted on simulated modules to demonstrate that all environmental specifications (wind loading, hailstone impact, thermal cycling, and humidity cycling) are satisfied by the design. All tests, except hailstone impact, were successfully completed. The assembly sequence was simplified by virtue of eliminating the frame components and assembly steps. Performance was improved by reducing the module edge border required to accommodate the frame of the preliminary design module. An ultrasonic rolling spot bonding technique was selected for use in the machine to perform the aluminum interconnect to cell metallization electrical joints required in the MEPSDU module configuration. This selection was based on extensive experimental tests and economic analyses.

Water System Adaptation To Hydrological Changes: Module 15, Course Summary and Project Presentation

EPA Science Inventory

This course will introduce students to the fundamental principles of water system adaptation to hydrological changes, with emphasis on data analysis and interpretation, technical planning, and computational modeling. Starting with real-world scenarios and adaptation needs, the co...

Water System Adaptation To Hydrological Changes: Module 11, Methods and Tools: Computational Models

EPA Science Inventory

This course will introduce students to the fundamental principles of water system adaptation to hydrological changes, with emphasis on data analysis and interpretation, technical planning, and computational modeling. Starting with real-world scenarios and adaptation needs, the co...

Task-induced frequency modulation features for brain-computer interfacing

NASA Astrophysics Data System (ADS)

Jayaram, Vinay; Hohmann, Matthias; Just, Jennifer; Schölkopf, Bernhard; Grosse-Wentrup, Moritz

2017-10-01

Objective. Task-induced amplitude modulation of neural oscillations is routinely used in brain-computer interfaces (BCIs) for decoding subjects’ intents, and underlies some of the most robust and common methods in the field, such as common spatial patterns and Riemannian geometry. While there has been some interest in phase-related features for classification, both techniques usually presuppose that the frequencies of neural oscillations remain stable across various tasks. We investigate here whether features based on task-induced modulation of the frequency of neural oscillations enable decoding of subjects’ intents with an accuracy comparable to task-induced amplitude modulation. Approach. We compare cross-validated classification accuracies using the amplitude and frequency modulated features, as well as a joint feature space, across subjects in various paradigms and pre-processing conditions. We show results with a motor imagery task, a cognitive task, and also preliminary results in patients with amyotrophic lateral sclerosis (ALS), as well as using common spatial patterns and Laplacian filtering. Main results. The frequency features alone do not significantly out-perform traditional amplitude modulation features, and in some cases perform significantly worse. However, across both tasks and pre-processing in healthy subjects the joint space significantly out-performs either the frequency or amplitude features alone. This result only does not hold for ALS patients, for whom the dataset is of insufficient size to draw any statistically significant conclusions. Significance. Task-induced frequency modulation is robust and straight forward to compute, and increases performance when added to standard amplitude modulation features across paradigms. This allows more information to be extracted from the EEG signal cheaply and can be used throughout the field of BCIs.

Joint Cross-Layer Design for Wireless QoS Content Delivery

NASA Astrophysics Data System (ADS)

Chen, Jie; Lv, Tiejun; Zheng, Haitao

2005-12-01

In this paper, we propose a joint cross-layer design for wireless quality-of-service (QoS) content delivery. Central to our proposed cross-layer design is the concept of adaptation. Adaptation represents the ability to adjust protocol stacks and applications to respond to channel variations. We focus our cross-layer design especially on the application, media access control (MAC), and physical layers. The network is designed based on our proposed fast frequency-hopping orthogonal frequency division multiplex (OFDM) technique. We also propose a QoS-awareness scheduler and a power adaptation transmission scheme operating at both the base station and mobile sides. The proposed MAC scheduler coordinates the transmissions of an IP base station and mobile nodes. The scheduler also selects appropriate transmission formats and packet priorities for individual users based on current channel conditions and the users' QoS requirements. The test results show that our cross-layer design provides an excellent framework for wireless QoS content delivery.

Rack assembly for mounting solar modules

DOEpatents

Plaisted, Joshua Reed; West, Brian

2010-12-28

A rack assembly is provided for mounting solar modules over an underlying body. The rack assembly may include a plurality of rail structures that are arrangeable over the underlying body to form an overall perimeter for the rack assembly. One or more retention structures may be provided with the plurality of rail structures, where each retention structure is configured to support one or more solar modules at a given height above the underlying body. At least some of the plurality of rail structures are adapted to enable individual rail structures o be sealed over the underlying body so as to constrain air flow underneath the solar modules. Additionally, at least one of (i) one or more of the rail structures, or (ii) the one or more retention structures are adjustable so as to adapt the rack assembly to accommodate solar modules of varying forms or dimensions.

Rack assembly for mounting solar modules

DOEpatents

Plaisted, Joshua Reed; West, Brian

2012-09-04

A rack assembly is provided for mounting solar modules over an underlying body. The rack assembly may include a plurality of rail structures that are arrangeable over the underlying body to form an overall perimeter for the rack assembly. One or more retention structures may be provided with the plurality of rail structures, where each retention structure is configured to support one or more solar modules at a given height above the underlying body. At least some of the plurality of rail structures are adapted to enable individual rail structures to be sealed over the underlying body so as to constrain air flow underneath the solar modules. Additionally, at least one of (i) one or more of the rail structures, or (ii) the one or more retention structures are adjustable so as to adapt the rack assembly to accommodate solar modules of varying forms or dimensions.

Rack assembly for mounting solar modules

DOEpatents

Plaisted, Joshua Reed; West, Brian

2014-06-10

A rack assembly is provided for mounting solar modules over an underlying body. The rack assembly may include a plurality of rail structures that are arrangeable over the underlying body to form an overall perimeter for the rack assembly. One or more retention structures may be provided with the plurality of rail structures, where each retention structure is configured to support one or more solar modules at a given height above the underlying body. At least some of the plurality of rail structures are adapted to enable individual rail structures o be sealed over the underlying body so as to constrain air flow underneath the solar modules. Additionally, at least one of (i) one or more of the rail structures, or (ii) the one or more retention structures are adjustable so as to adapt the rack assembly to accommodate solar modules of varying forms or dimensions.

Adaptive velocity-based six degree of freedom load control for real-time unconstrained biomechanical testing.

PubMed

Lawless, I M; Ding, B; Cazzolato, B S; Costi, J J

2014-09-22

Robotic biomechanics is a powerful tool for further developing our understanding of biological joints, tissues and their repair. Both velocity-based and hybrid force control methods have been applied to biomechanics but the complex and non-linear properties of joints have limited these to slow or stepwise loading, which may not capture the real-time behaviour of joints. This paper presents a novel force control scheme combining stiffness and velocity based methods aimed at achieving six degree of freedom unconstrained force control at physiological loading rates. Copyright © 2014 Elsevier Ltd. All rights reserved.

Apollo Spacecraft 012 Command/Service Module being moved to Operations bldg

NASA Technical Reports Server (NTRS)

1967-01-01

Apollo Spacecraft 012 Command/Service Module is moved from H-134 to east stokes for mating to the Saturn Lunar Module Adapter No. 05 in the Manned Spacecraft Operations bldg. S/C 012 will be flown on the Apollo/Saturn 204 mission.

Membrane module assembly

DOEpatents

Kaschemekat, Jurgen

1994-01-01

A membrane module assembly adapted to provide a flow path for the incoming feed stream that forces it into prolonged heat-exchanging contact with a heating or cooling mechanism. Membrane separation processes employing the module assembly are also disclosed. The assembly is particularly useful for gas separation or pervaporation.

KENNEDY SPACE CENTER, FLA. - The U.S. Node 2 is undergoing a Multi-Element Integrated Test (MEIT) in the Space Station Processing Facility. Node 2 attaches to the end of the U.S. Lab on the ISS and provides attach locations for the Japanese laboratory, European laboratory, the Centrifuge Accommodation Module and, eventually, Multipurpose Logistics Modules. It will provide the primary docking location for the Shuttle when a pressurized mating adapter is attached to Node 2. Installation of the module will complete the U.S. Core of the ISS.

NASA Image and Video Library

2003-08-27

KENNEDY SPACE CENTER, FLA. - The U.S. Node 2 is undergoing a Multi-Element Integrated Test (MEIT) in the Space Station Processing Facility. Node 2 attaches to the end of the U.S. Lab on the ISS and provides attach locations for the Japanese laboratory, European laboratory, the Centrifuge Accommodation Module and, eventually, Multipurpose Logistics Modules. It will provide the primary docking location for the Shuttle when a pressurized mating adapter is attached to Node 2. Installation of the module will complete the U.S. Core of the ISS.

Adapting the SLIM diabetes prevention intervention to a Dutch real-life setting: joint decision making by science and practice.

PubMed

Jansen, Sophia C; Haveman-Nies, Annemien; Duijzer, Geerke; Ter Beek, Josien; Hiddink, Gerrit J; Feskens, Edith J M

2013-05-08

Although many evidence-based diabetes prevention interventions exist, they are not easily applicable in real-life settings. Moreover, there is a lack of examples which describe the adaptation process of these interventions to practice. In this paper we present an example of such an adaptation. We adapted the SLIM (Study on Lifestyle intervention and Impaired glucose tolerance Maastricht) diabetes prevention intervention to a Dutch real-life setting, in a joint decision making process of intervention developers and local health care professionals. We used 3 adaptation steps in accordance with current adaptation frameworks. In the first step, the elements of the SLIM intervention were identified. In the second step, these elements were judged for their applicability in a real-life setting. In the third step, adaptations were proposed and discussed for those elements which were deemed not applicable. Participants invited for this process included intervention developers and local health care professionals (n=19). In the first adaptation step, a total of 22 intervention elements were identified. In the second step, 12 of these 22 intervention elements were judged as inapplicable. In the third step, a consensus was achieved for the adaptations of all 12 elements. The adapted elements were in the following categories: target population, techniques, intensity, delivery mode, materials, organisational structure, and political and financial conditions. The adaptations either lay in changing the SLIM protocol (6 elements) or the real-life working procedures (1 element), or a combination of both (4 elements). The positive result of this study is that a consensus was achieved within a relatively short time period (nine months) between the developers of the SLIM intervention and local health care professionals on the adaptations needed to make SLIM applicable in a Dutch real-life setting. Our example shows that it is possible to combine the perspectives of scientists and practitioners, and to find a balance between evidence-base and applicability concerns.

Low-complexity nonlinear adaptive filter based on a pipelined bilinear recurrent neural network.

PubMed

Zhao, Haiquan; Zeng, Xiangping; He, Zhengyou

2011-09-01

To reduce the computational complexity of the bilinear recurrent neural network (BLRNN), a novel low-complexity nonlinear adaptive filter with a pipelined bilinear recurrent neural network (PBLRNN) is presented in this paper. The PBLRNN, inheriting the modular architectures of the pipelined RNN proposed by Haykin and Li, comprises a number of BLRNN modules that are cascaded in a chained form. Each module is implemented by a small-scale BLRNN with internal dynamics. Since those modules of the PBLRNN can be performed simultaneously in a pipelined parallelism fashion, it would result in a significant improvement of computational efficiency. Moreover, due to nesting module, the performance of the PBLRNN can be further improved. To suit for the modular architectures, a modified adaptive amplitude real-time recurrent learning algorithm is derived on the gradient descent approach. Extensive simulations are carried out to evaluate the performance of the PBLRNN on nonlinear system identification, nonlinear channel equalization, and chaotic time series prediction. Experimental results show that the PBLRNN provides considerably better performance compared to the single BLRNN and RNN models.

The effect of footwear adapted with a multi-curved rocker sole in conjunction with knee-ankle-foot orthoses on walking in poliomyelitis subjects: a pilot study.

PubMed

Mojaver, Ali; Arazpour, Mokhtar; Aminian, Gholamreza; Ahmadi Bani, Monireh; Bahramizadeh, Mahmood; Sharifi, Guive; Sherafatvaziri, Arash

2017-10-01

Knee-ankle-foot orthoses (KAFOs) are used by people with poliomyelitis to ambulate. Whist advances in orthotic knee joint designs for use in KAFOs such the provision of stance control capability have proven efficacy, little attention has been paid to shoe adaptations which may also improve gait. The aim of this study was to evaluate the alteration to the kinematics and temporal-spatial parameters of gait caused by the use of heel-to-toe rocker-soled footwear when ambulating with KAFOs. Nine adults with a history of poliomyelitis who routinely wore KAFOs participated in the study. A heel-to-toe rocker sole was added to footwear and worn on the affected side. A three-dimensional motion capture system was used to quantify the resulting alteration to specific gait parameters. Maximum hip joint extension was significantly increased (p = 0.011), and hip abduction and adduction were both significantly reduced (p = 0.011 and p = 0.007, respectively) when walking with the rocker sole. A significant increase in stride length (p = 0.035) was demonstrated but there were no significant increases in either walking speed or cadence. A heel-to-toe rocker sole adaptation may be useful for walking in patients with poliomyelitis who use KAFOs. Implications for Rehabilitation The poor functionality and difficulty in walking when using an orthotic device such as a KAFO which keeps the knee locked during ambulation, plus the significant energy required to walk, are complications of orthoses using. Little evidence exists regarding the biomechanical effect of walking with a KAFO incorporating fixed knee joints, in conjunction with rocker-soled footwear. The main aim of walking with a heel-to-toe rocker sole is to facilitate forward progression of the tibia when used with an AFO or KAFO or to provide easier walking for patients who have undergone an ankle arthrodesis. In this study, a rocker sole profile adaptation produced no significant alteration to hip joint flexion, but hip joint maximum extension was significantly increased in subjects suffering from poliomyelitis, and maximum hip adduction and abduction were both significantly reduced. The most significant alterations were seen in stride length, and although there was a significant increase in this parameter, there was no statistically significant increase in walking velocity or cadence.

Sex differences in kinematic adaptations to muscle fatigue induced by repetitive upper limb movements.

PubMed

Bouffard, Jason; Yang, Chen; Begon, Mickael; Côté, Julie

2018-04-19

Muscle fatigue induced by repetitive movements contributes to the development of musculoskeletal disorders. Men and women respond differently to muscle fatigue during isometric single-joint efforts, but sex differences during dynamic multi-joint tasks have not been clearly identified. Moreover, most studies comparing men and women during fatigue development assessed endurance time. However, none evaluated sex differences in kinematic adaptations to fatigue during multi-joint dynamic tasks. The objective of the study was to compare how men and women adapt their upper body kinematics during a fatiguing repetitive pointing task. Forty men and 41 women performed repetitive pointing movements (one per second) between two targets while maintaining their elbow elevated at shoulder height. The task ended when participants rated a perceived level of fatigue of 8/10. Trunk, humerothoracic, and elbow angles were compared between the first and last 30 s of the experiment and between men and women. Linear positions of the index finger (distance from the target) and the elbow (arm elevation) as well as movement timing were documented as task performance measures. Men (7.4 ± 3.2 min) and women (8.3 ± 4.5 min) performed the repetitive pointing task for a similar duration. For both sex groups, trunk range of motion increased with fatigue while shoulder's and elbow's decreased. Moreover, participants modified their trunk posture to compensate for the decreased humerothoracic elevation. Movements at all joints also became more variable with fatigue. However, of the 24 joint angle variables assessed, only two Sex × Fatigue interactions were observed. Although average humerothoracic elevation angle decreased in both subgroups, this decrease was greater in men (standardized response mean [SRM] - 1.63) than in women (SRM - 1.44). Moreover, the movement-to-movement variability of humerothoracic elevation angle increased only in women (SRM 0.42). Despite many similarities between men's and women's response to fatigue induced by repetitive pointing movements, some sex differences were observed. Those subtle differences may indicate that men's shoulder muscles were more fatigued than women's despite a similar level of perceived exertion. They may also indicate that men and women do not adapt the exact same way to a similar fatigue.

Stakeholder Analysis for the CF Counter-IED Training Courses

DTIC Science & Technology

2010-05-01

for more than purely research purposes when the experimenter is present. 3.1.3 Learning Style- based Adaptation The Index of Learning Styles (Felder...student. It is recommended that the Adaption Module uses the same ontology based reasoning approach as the Evaluation Module. RacerPro is the recommended...reasoner. RacerPro is used as a system for managing semantic web ontologies based on Web Ontology Language (OWL). The design phase will confirm

Segregating Variation in the Polycomb Group Gene cramped Alters the Effect of Temperature on Multiple Traits

PubMed Central

Gibert, Jean-Michel; Karch, François; Schlötterer, Christian

2011-01-01

The phenotype produced by a given genotype can be strongly modulated by environmental conditions. Therefore, natural populations continuously adapt to environment heterogeneity to maintain optimal phenotypes. It generates a high genetic variation in environment-sensitive gene networks, which is thought to facilitate evolution. Here we analyze the chromatin regulator crm, identified as a candidate for adaptation of Drosophila melanogaster to northern latitudes. We show that crm contributes to environmental canalization. In particular, crm modulates the effect of temperature on a genomic region encoding Hedgehog and Wingless signaling effectors. crm affects this region through both constitutive heterochromatin and Polycomb silencing. Furthermore, we show that crm European and African natural variants shift the reaction norms of plastic traits. Interestingly, traits modulated by crm natural variants can differ markedly between Drosophila species, suggesting that temperature adaptation facilitates their evolution. PMID:21283785

The research on thermal adaptability reinforcement technology for photovoltaic modules

NASA Astrophysics Data System (ADS)

Su, Nana; Zhou, Guozhong

2015-10-01

Nowadays, Photovoltaic module contains more high-performance components in smaller space. It is also demanded to work in severe temperature condition for special use, such as aerospace. As temperature rises, the failure rate will increase exponentially which makes reliability significantly reduce. In order to improve thermal adaptability of photovoltaic module, this paper makes a research on reinforcement technologies. Thermoelectric cooler is widely used in aerospace which has harsh working environment. So, theoretical formulas for computing refrigerating efficiency, refrigerating capacity and temperature difference are described in detail. The optimum operating current of three classical working condition is obtained which can be used to guide the design of driven circuit. Taken some equipment enclosure for example, we use thermoelectric cooler to reinforce its thermal adaptability. By building physical model and thermal model with the aid of physical dimension and constraint condition, the model is simulated by Flotherm. The temperature field cloud is shown to verify the effectiveness of reinforcement.

Adaptive Incentive Controls for Stackelberg Games with Unknown Cost Functionals.

DTIC Science & Technology

1984-01-01

APR EZT:: F I AN 73S e OsL:-: UNCLASSI?:-- Q4~.’~- .A.., 6, *~*i i~~*~~*.- U ADAPTIVE INCENTIVE CONTROLS FOR STACKELBERG GAMES WITH UNKNOWN COST...AD-A161 885 ADAPTIVE INCENTIVE CONTROLS FOR STACKELBERG GAMES WITH i/1 UNKNOWN COST FUNCTIONALSCU) ILLINOIS UNIV AT URBANA DECISION AND CONTROL LAB T...ORGANIZATION 6b. OFFICE SYMBOL 7.. NAME OF MONITORING ORGANIZATION CoriaeLcenef~pda~ Joint Services Electronics Program Laboratory, Univ. of Illinois N/A

The Extended School Year: A Report to the Washington State Legislature by the Subcommittee on School Organization and Management of the Joint Committee on Education.

ERIC Educational Resources Information Center

Washington State Legislative Council, Olympia.

The Joint Committee was directed to study (1) the four quarter system for public schools; (2) other variations and adaptations of a 12-month school year, including the feasibility of a State supported, tuition-free, summer educational and recreational program; and (3) educational, vocational, and recreational programs, supported by fees or…

Pins and Rubbers Traction System.

PubMed

de Soras, X; de Mourgues, P; Guinard, D; Moutet, F

1997-12-01

The Pins and Rubbers Traction System (PRTS) is a mobile frame created with wires to support elastic traction, which produces a ligamentotaxis effect in the same direction and of the same intensity whatever the position of the joint. This technique has been used in 11 cases of complex PIP joint fractures with eight excellent results. The advantages are simplicity, adaptability, the possibility of immediate mobilization, reasonable cost and relatively small bulk.

Command and Control of Joint Air Operations through Mission Command

DTIC Science & Technology

2016-06-01

and outlines the C2 architecture systems, processes, and philosophy of com- mand required to enable mission command effectively. Mission Command...General Dempsey highlights the fact that “trust is the moral sinew that binds the distributed Joint Force 2020 together” and observes that “unless...con- fident about how their subordinates will make decisions and adapt to the dynamic battlespace environment. Processes, Systems, and Philosophy of

Physical therapy applications of MR fluids and intelligent control

NASA Astrophysics Data System (ADS)

Dong, Shufang; Lu, Ke-Qian; Sun, J. Q.; Rudolph, Katherine

2005-05-01

Resistance exercise has been widely reported to have positive rehabilitation effects for patients with neuromuscular and orthopaedic conditions. This paper presents an optimal design of magneto-rheological fluid dampers for variable resistance exercise devices. Adaptive controls for regulating the resistive force or torque of the device as well as the joint motion are presented. The device provides both isometric and isokinetic strength training for various human joints.

SU-E-J-110: A Novel Level Set Active Contour Algorithm for Multimodality Joint Segmentation/Registration Using the Jensen-Rényi Divergence.

PubMed

Markel, D; Naqa, I El; Freeman, C; Vallières, M

2012-06-01

To present a novel joint segmentation/registration for multimodality image-guided and adaptive radiotherapy. A major challenge to this framework is the sensitivity of many segmentation or registration algorithms to noise. Presented is a level set active contour based on the Jensen-Renyi (JR) divergence to achieve improved noise robustness in a multi-modality imaging space. To present a novel joint segmentation/registration for multimodality image-guided and adaptive radiotherapy. A major challenge to this framework is the sensitivity of many segmentation or registration algorithms to noise. Presented is a level set active contour based on the Jensen-Renyi (JR) divergence to achieve improved noise robustness in a multi-modality imaging space. It was found that JR divergence when used for segmentation has an improved robustness to noise compared to using mutual information, or other entropy-based metrics. The MI metric failed at around 2/3 the noise power than the JR divergence. The JR divergence metric is useful for the task of joint segmentation/registration of multimodality images and shows improved results compared entropy based metric. The algorithm can be easily modified to incorporate non-intensity based images, which would allow applications into multi-modality and texture analysis. © 2012 American Association of Physicists in Medicine.

Adaptive alterations of elastic fibers in the bilaminar zone of rabbit temporomandibular joint following disc displacement.

PubMed

Gu, Zhiyuan; Wu, Huiling; Feng, Jianying; Shibata, Takanori; Hu, Ji'an; Zhang, Yinkai; Xie, Zhijian

2002-12-01

To study the adaptive alterations of elastic fibers in the bilaminar zone (BZ) of rabbit temporomandibular joint (TMJ) following disc displacement. Twenty-eight Japanese white rabbits were used in this study. The right temporomandibular joints of 20 of 28 rabbits were subjected to the surgical procedure of anterior disc displacement (ADD). Four rabbits in the surgical group were sacrificed at 2, 4, 6, 8 and 12 weeks after operation. Their temporomandibular joints were studied histochemically. Elastic fibers were reduced in number and ran irregularly in the superior lamina of BZ from ADD rabbits. The jungly elastic fibers (EFs) could still be seen at 2 weeks after operation. At 4 weeks, the number of EFs decreased significantly; EFs lost their jungly arrangement and were shaped like rough dots, of which the arrangement and the lengths were different. Six weeks after operation, many EFs were replaced by distorted, uneven, non-oriented fine EFs, distributed unevenly and some thick or fine EFs that ran irregularly. The number of EFs decreased further and their arrangement was more deranged at 8 weeks. At 10 and 12 weeks, EFs in the superior lamina of BZ were similar to those at 8 weeks. Our results show that EFs lost their function as well as their distribution and arrangement after disc displacement.

Design of the helium cooled lithium lead breeding blanket in CEA: from TBM to DEMO

NASA Astrophysics Data System (ADS)

Aiello, G.; Aubert, J.; Forest, L.; Jaboulay, J.-C.; Li Puma, A.; Boccaccini, L. V.

2017-04-01

The helium cooled lithium lead (HCLL) blanket concept was originally developed in CEA at the beginning of 2000: it is one of the two European blanket concepts to be tested in ITER in the form of a test blanket module (TBM) and one of the four blanket concepts currently being considered for the DEMOnstration reactor that will follow ITER. The TBM is a highly optimized component for the ITER environment that will provide crucial information for the development of the DEMO blanket, but its design needs to be adapted to the DEMO reactor. With respect to the TBM design, reduction of the steel content in the breeding zone (BZ) is sought in order to maximize tritium breeding reactions. Different options are being studied, with the potential of reaching tritium breeding ratio (TBR) values up to 1.21. At the same time, the design of the back supporting structure (BSS), which is a DEMO specific component that has to support the blanket modules inside the vacuum vessel (VV), is ongoing with the aim of maximizing the shielding power and minimizing pumping power. This implies a re-engineering of the modules’ attachment system. Design changes however, will have an impact on the manufacturing and assembly sequences that are being developed for the HCLL-TBM. Due to the differences in joint configurations, thicknesses to be welded, heat dissipation and the various technical constraints related to the accessibility of the welding tools and implementation of non-destructive examination (NDE), the manufacturing procedure should be adapted and optimized for DEMO design. Laser welding instead of TIG could be an option to reduce distortions. The time-of-flight diffraction (TOFD) technique is being investigated for NDE. Finally, essential information expected from the HCLL-TBM program that will be needed to finalize the DEMO design is discussed.

Simplified flexible-PON upstream transmission using pulse position modulation at ONU and DSP-enabled soft-combining at OLT for adaptive link budgets.

PubMed

Liu, Xiang; Effenberger, Frank; Chand, Naresh

2015-03-09

We demonstrate a flexible modulation and detection scheme for upstream transmission in passive optical networks using pulse position modulation at optical network unit, facilitating burst-mode detection with automatic decision threshold tracking, and DSP-enabled soft-combining at optical line terminal. Adaptive receiver sensitivities of -33.1 dBm, -36.6 dBm and -38.3 dBm at a bit error ratio of 10(-4) are respectively achieved for 2.5 Gb/s, 1.25 Gb/s and 625 Mb/s after transmission over a 20-km standard single-mode fiber without any optical amplification.

Neural joint control for Space Shuttle Remote Manipulator System

NASA Technical Reports Server (NTRS)

Atkins, Mark A.; Cox, Chadwick J.; Lothers, Michael D.; Pap, Robert M.; Thomas, Charles R.

1992-01-01

Neural networks are being used to control a robot arm in a telerobotic operation. The concept uses neural networks for both joint and inverse kinematics in a robotic control application. An upper level neural network is trained to learn inverse kinematic mappings. The output, a trajectory, is then fed to the Decentralized Adaptive Joint Controllers. This neural network implementation has shown that the controlled arm recovers from unexpected payload changes while following the reference trajectory. The neural network-based decentralized joint controller is faster, more robust and efficient than conventional approaches. Implementations of this architecture are discussed that would relax assumptions about dynamics, obstacles, and heavy loads. This system is being developed to use with the Space Shuttle Remote Manipulator System.

Water System Adaptation To Hydrological Changes: Module 8, Regulatory Framework Intersections: Past, Present, and Future

EPA Science Inventory

This course will introduce students to the fundamental principles of water system adaptation to hydrological changes, with emphasis on data analysis and interpretation, technical planning, and computational modeling. Starting with real-world scenarios and adaptation needs, the co...

Design and evaluation of a quasi-passive knee exoskeleton for investigation of motor adaptation in lower extremity joints.

PubMed

Shamaei, Kamran; Cenciarini, Massimo; Adams, Albert A; Gregorczyk, Karen N; Schiffman, Jeffrey M; Dollar, Aaron M

2014-06-01

In this study, we describe the mechanical design and control scheme of a quasi-passive knee exoskeleton intended to investigate the biomechanical behavior of the knee joint during interaction with externally applied impedances. As the human knee behaves much like a linear spring during the stance phase of normal walking gait, the exoskeleton implements a spring across the knee in the weight acceptance (WA) phase of the gait while allowing free motion throughout the rest of the gait cycle, accomplished via an electromechanical clutch. The stiffness of the device is able to be varied by swapping springs, and the timing of engagement/disengagement changed to accommodate different loading profiles. After describing the design and control, we validate the mechanical performance and reliability of the exoskeleton through cyclic testing on a mechanical knee simulator. We then describe a preliminary experiment on three healthy adults to evaluate the functionality of the device on both left and right legs. The kinetic and kinematic analyses of these subjects show that the exoskeleton assistance can partially/fully replace the function of the knee joint and obtain nearly invariant moment and angle profiles for the hip and ankle joints, and the overall knee joint and exoskeleton complex under the applied moments of the exoskeleton versus the control condition, implying that the subjects undergo a considerable amount of motor adaptation in their lower extremities to the exoskeletal impedances, and encouraging more in-depth future experiments with the device.

Adaptations in single-leg hop biomechanics following anterior cruciate ligament reconstruction.

PubMed

Orishimo, Karl F; Kremenic, Ian J; Mullaney, Michael J; McHugh, Malachy P; Nicholas, Stephen J

2010-11-01

When a patient performs a clinically normal hop test based on distance, it cannot be assumed that the biomechanics are similar between limbs. The objective was to compare takeoff and landing biomechanics between legs in patients who have undergone anterior cruciate ligament reconstruction. Kinematics and ground reaction forces were recorded as 13 patients performed the single-leg hop on each leg. Distance hopped, joint range of motion, peak joint kinetics and the peak total extensor moment were compared between legs during both takeoff and landing. Average hop distance ratio (involved/noninvolved) was 93 ± 4%. Compared to the noninvolved side, knee motion during takeoff on the involved side was significantly reduced (P = 0.008). Peak moments and powers on the involved side were lower at the knee and higher at the ankle and hip compared with the noninvolved side (Side by Joint P = 0.011; P = 0.003, respectively). The peak total extensor moment was not different between legs (P = 0.305) despite a decrease in knee moment and increases in ankle and hip moments (Side by Joint P = 0.015). During landing, knee motion was reduced (P = 0.043), and peak power absorbed was decreased at the knee and hip and increased at the ankle on the involved side compared to the noninvolved side (P = 0.003). The compensations by other joints may indicate protective adaptations to avoid overloading the reconstructed knee.

Construction Management Module: Contingency Contracting Synergistic Approach Integrating Joint Capabilities for USSOCOM

DTIC Science & Technology

2010-01-29

mr_if`=mlif`v - ix - k^s^i=mlpqdo^ar^qb=p`elli= Acronym Listing AAR After-action Report ACC Acquisition Community Connection ADDIE Analyze...J3 Operations J4 Logistics J5 Plans J6 Communications J8 Programming and Comptroller J&A Justification and Approval JARB Joint...Due to geographical and communication constraints, the sample of informants was limited to 20 current USSOCOM personnel. However, the

Simulations - Joint NASA-USSR Mission - JSC

NASA Image and Video Library

1975-02-25

S75-22187 (25 Feb. 1975) --- Two ASTP crewmen look over food cans and packages in the Soyuz orbital module trainer in Building 35 during Apollo-Soyuz Test Project joint crew training at NASA's Johnson Space Center. They are astronaut Thomas P. Stafford (left), commander of the American ASTP prime crew; and cosmonaut Aleksey A. Leonov, commander of the Soviet ASTP first (prime) crew. The training session simulated activity on the second day in Earth orbit.

Smart Acoustic Network Using Combined FSK-PSK, Adaptive Beamforming and Equalization

DTIC Science & Technology

2002-09-30

sonar data transmission from underwater vehicle during mission. The two-year objectives for the high-reliability acoustic network using multiple... sonar laboratory) and used for acoustic networking during underwater vehicle operation. The joint adaptive coherent path beamformer method consists...broadband communications transducer, while the low noise preamplifier conditions received signals for analog to digital conversion. External user

Smart Acoustic Network Using Combined FSK-PSK, Adaptive, Beamforming and Equalization

DTIC Science & Technology

2001-09-30

sonar data transmission from underwater vehicle during mission. The two-year objectives for the high-reliability acoustic network using multiple... sonar laboratory) and used for acoustic networking during underwater vehicle operation. The joint adaptive coherent path beamformer method consists...broadband communications transducer, while the low noise preamplifier conditions received signals for analog to digital conversion. External user

Application for managing model-based material properties for simulation-based engineering

DOEpatents

Hoffman, Edward L [Alameda, CA

2009-03-03

An application for generating a property set associated with a constitutive model of a material includes a first program module adapted to receive test data associated with the material and to extract loading conditions from the test data. A material model driver is adapted to receive the loading conditions and a property set and operable in response to the loading conditions and the property set to generate a model response for the material. A numerical optimization module is adapted to receive the test data and the model response and operable in response to the test data and the model response to generate the property set.

Adaptive channel estimation for soft decision decoding over non-Gaussian optical channel

NASA Astrophysics Data System (ADS)

Xiang, Jing-song; Miao, Tao-tao; Huang, Sheng; Liu, Huan-lin

2016-10-01

An adaptive priori likelihood ratio (LLR) estimation method is proposed over non-Gaussian channel in the intensity modulation/direct detection (IM/DD) optical communication systems. Using the nonparametric histogram and the weighted least square linear fitting in the tail regions, the LLR is estimated and used for the soft decision decoding of the low-density parity-check (LDPC) codes. This method can adapt well to the three main kinds of intensity modulation/direct detection (IM/DD) optical channel, i.e., the chi-square channel, the Webb-Gaussian channel and the additive white Gaussian noise (AWGN) channel. The performance penalty of channel estimation is neglected.

Ball and Socket Ankle: Mechanism and Computational Evidence of Concept.

PubMed

Jastifer, James R; Gustafson, Peter A; Labomascus, Aaron; Snoap, Tyler

The ball and socket ankle joint is a morphologically abnormal joint characterized by rounding of the articular surface of the talus. Other than anecdotal observation, little evidence has been presented to describe the development of this deformity. The purpose of the present study was to review ankle and subtalar joint mechanics and to kinematically examine the functional combination of these joints as a mechanism of the ball and socket ankle deformity. We reviewed functional representations of the ankle joint, subtalar joint, and ball and socket ankle deformity. A computational study of joint kinematics was then performed using a 3-dimensional model derived from a computed tomography scan of a ball and socket deformity. The joint kinematics were captured by creating a "virtual map" of the combined kinematics of the ankle and subtalar joints in the respective models. The ball and socket ankle deformity produces functionally similar kinematics to a combination of the ankle and subtalar joints. The findings of the present study support the notion that a possible cause of the ball and socket deformity is bony adaptation that compensates for a functional deficit of the ankle and subtalar joints. Copyright © 2017 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

Adaptive control of center of mass (global) motion and its joint (local) origin in gait.

PubMed

Yang, Feng; Pai, Yi-Chung

2014-08-22

Dynamic gait stability can be quantified by the relationship of the motion state (i.e. the position and velocity) between the body center of mass (COM) and its base of support (BOS). Humans learn how to adaptively control stability by regulating the absolute COM motion state (i.e. its position and velocity) and/or by controlling the BOS (through stepping) in a predictable manner, or by doing both simultaneously following an external perturbation that disrupts their regular relationship. Post repeated-slip perturbation training, for instance, older adults learned to forward shift their COM position while walking with a reduced step length, hence reduced their likelihood of slip-induced falls. How and to what extent each individual joint influences such adaptive alterations is mostly unknown. A three-dimensional individualized human kinematic model was established. Based on the human model, sensitivity analysis was used to systematically quantify the influence of each lower limb joint on the COM position relative to the BOS and the step length during gait. It was found that the leading foot had the greatest effect on regulating the COM position relative to the BOS; and both hips bear the most influence on the step length. These findings could guide cost-effective but efficient fall-reduction training paradigm among older population. Copyright © 2014 Elsevier Ltd. All rights reserved.

System identification and model reduction using modulating function techniques

NASA Technical Reports Server (NTRS)

Shen, Yan

1993-01-01

Weighted least squares (WLS) and adaptive weighted least squares (AWLS) algorithms are initiated for continuous-time system identification using Fourier type modulating function techniques. Two stochastic signal models are examined using the mean square properties of the stochastic calculus: an equation error signal model with white noise residuals, and a more realistic white measurement noise signal model. The covariance matrices in each model are shown to be banded and sparse, and a joint likelihood cost function is developed which links the real and imaginary parts of the modulated quantities. The superior performance of above algorithms is demonstrated by comparing them with the LS/MFT and popular predicting error method (PEM) through 200 Monte Carlo simulations. A model reduction problem is formulated with the AWLS/MFT algorithm, and comparisons are made via six examples with a variety of model reduction techniques, including the well-known balanced realization method. Here the AWLS/MFT algorithm manifests higher accuracy in almost all cases, and exhibits its unique flexibility and versatility. Armed with this model reduction, the AWLS/MFT algorithm is extended into MIMO transfer function system identification problems. The impact due to the discrepancy in bandwidths and gains among subsystem is explored through five examples. Finally, as a comprehensive application, the stability derivatives of the longitudinal and lateral dynamics of an F-18 aircraft are identified using physical flight data provided by NASA. A pole-constrained SIMO and MIMO AWLS/MFT algorithm is devised and analyzed. Monte Carlo simulations illustrate its high-noise rejecting properties. Utilizing the flight data, comparisons among different MFT algorithms are tabulated and the AWLS is found to be strongly favored in almost all facets.

High-frequency modulation of the four states of polarization of light with a single phase modulator

NASA Astrophysics Data System (ADS)

Compain, Eric; Drevillon, Bernard

1998-04-01

A method for light polarization modulation is described. It allows us to independently modulate, at a high frequency, the four components of the Stokes vector of light using a single phase modulator. It works in a double-pass configuration: the polarization of light is modulated a first time by the phase modulator, and is then modified by a coupling object before being modulated a second time by the same modulator. The coupling object consists of multiple glass plates, oriented at the Brewster angle, acting as a partial polarizer and in a right angle prism acting as a phase shifter and back reflector. Its polarimetric properties are obtained from refractive index contrast effects, which provides optimized and constant properties over a wide spectral range. The phase modulator can be either an electro-optic modulator providing a very high-frequency capability (up to 100 MHz) or a photoelastic modulator providing a wide spectral range capability. It is robust because there is no moving part and simple to implement because of the presence of one modulation. It displays a high level of sensitivity because all the components are high-frequency modulated. Two applications using this modulator in a polarimeter or in a polarization states generator are described. The four modulations, having the same fundamental frequency, are easily demodulated by numerical data processing. Optimized demodulation processing, adapted to the different kind of phase modulator is described. Its adaptation taking into account the bandwidth limitation and the variation of the sampling phase, are finally presented in the case of a photoelastic modulator.

High-dynamic range imaging techniques based on both color-separation algorithms used in conventional graphic arts and the human visual perception modeling

NASA Astrophysics Data System (ADS)

Lo, Mei-Chun; Hsieh, Tsung-Hsien; Perng, Ruey-Kuen; Chen, Jiong-Qiao

2010-01-01

The aim of this research is to derive illuminant-independent type of HDR imaging modules which can optimally multispectrally reconstruct of every color concerned in high-dynamic-range of original images for preferable cross-media color reproduction applications. Each module, based on either of broadband and multispectral approach, would be incorporated models of perceptual HDR tone-mapping, device characterization. In this study, an xvYCC format of HDR digital camera was used to capture HDR scene images for test. A tone-mapping module was derived based on a multiscale representation of the human visual system and used equations similar to a photoreceptor adaptation equation, proposed by Michaelis-Menten. Additionally, an adaptive bilateral type of gamut mapping algorithm, using approach of a multiple conversing-points (previously derived), was incorporated with or without adaptive Un-sharp Masking (USM) to carry out the optimization of HDR image rendering. An LCD with standard color space of Adobe RGB (D65) was used as a soft-proofing platform to display/represent HDR original RGB images, and also evaluate both renditionquality and prediction-performance of modules derived. Also, another LCD with standard color space of sRGB was used to test gamut-mapping algorithms, used to be integrated with tone-mapping module derived.

Adaptive and perceptual learning technologies in medical education and training.

PubMed

Kellman, Philip J

2013-10-01

Recent advances in the learning sciences offer remarkable potential to improve medical education and maximize the benefits of emerging medical technologies. This article describes 2 major innovation areas in the learning sciences that apply to simulation and other aspects of medical learning: Perceptual learning (PL) and adaptive learning technologies. PL technology offers, for the first time, systematic, computer-based methods for teaching pattern recognition, structural intuition, transfer, and fluency. Synergistic with PL are new adaptive learning technologies that optimize learning for each individual, embed objective assessment, and implement mastery criteria. The author describes the Adaptive Response-Time-based Sequencing (ARTS) system, which uses each learner's accuracy and speed in interactive learning to guide spacing, sequencing, and mastery. In recent efforts, these new technologies have been applied in medical learning contexts, including adaptive learning modules for initial medical diagnosis and perceptual/adaptive learning modules (PALMs) in dermatology, histology, and radiology. Results of all these efforts indicate the remarkable potential of perceptual and adaptive learning technologies, individually and in combination, to improve learning in a variety of medical domains. Reprint & Copyright © 2013 Association of Military Surgeons of the U.S.

Separate channels for the analysis of the shape and the movement of moving visual stimulus.

PubMed

Tolhurst, D J

1973-06-01

1. The effects of temporal modulation on the properties of spatial frequency channels have been investigated using adaptation.2. Adapting to drifting sinusoidal gratings caused threshold elevation that was both spatial frequency and direction specific. Little systematic difference was found between the band widths of the elevation curves for drifting and stationary gratings.3. It was confirmed that adaptation fails to reveal channels at low spatial frequencies when stationary gratings are used. However, channels were revealed at frequencies at least as low as 0.66 c/deg when the test gratings were made to move. These channels are adapted only a little by stationary gratings, confirming their dependence on movement.4. The existence of movement-sensitive channels at low spatial frequencies explains the well known observation that temporal modulation greatly increases the sensitivity of the visual system to low spatial frequencies.5. Temporal modulation was effective at revealing these channels only when the flicker or movement of the test patterns was apparent to the observer; only at low spatial frequencies did patterns, modulated at low rates, actually appear to be temporarily modulated at threshold. At higher spatial frequencies, they were indistinguishable from stationary patterns until the contrast was some way above the detection threshold.6. It is suggested, therefore, that the movement-sensitive channels are responsible for signalling the occurrence of movement; the channels at higher spatial frequencies give no information about temporal changes. These two systems of channels are compared to the Y- and X-cells respectively of the cat.

A Novel Adaptive Modulation Based on Nondata-Aided Error Vector Magnitude in Non-Line-Of-Sight Condition of Wireless Sensor Network.

PubMed

Yang, Fan; Zeng, Xiaoping; Mao, Haiwei; Jian, Xin; Tan, Xiaoheng; Du, Derong

2018-01-15

The high demand for multimedia applications in environmental monitoring, invasion detection, and disaster aid has led to the rise of wireless sensor network (WSN). With the increase of reliability and diversity of information streams, the higher requirements on throughput and quality of service (QoS) have been put forward in data transmission between two sensor nodes. However, lower spectral efficiency becomes a bottleneck in non-line-of-sight (NLOS) transmission of WSN. This paper proposes a novel nondata-aided error vector magnitude based adaptive modulation (NDA-EVM-AM) to solve the problem. NDA-EVM is considered as a new metric to evaluate the quality of NLOS link for adaptive modulation in WSN. By modeling the NLOS scenario as the η - μ fading channel, a closed-form expression for the NDA-EVM of multilevel quadrature amplitude modulation (MQAM) signals over the η - μ fading channel is derived, and the relationship between SER and NDA-EVM is also formulated. Based on these results, NDA-EVM state machine is designed for adaptation strategy. The algorithmic complexity of NDA-EVM-AM is analyzed and the outage capacity of NDA-EVM-AM in an NLOS scenario is also given. The performances of NDA-EVM-AM are compared by simulation, and the results show that NDA-EVM-AM is an effective technique to be used in the NLOS scenarios of WSN. This technique can accurately reflect the channel variations and efficiently adjust modulation order to better match the channel conditions, hence, obtaining better performance in average spectral efficiency.

Advanced servo manipulator

DOEpatents

Holt, W.E.; Kuban, D.P.; Martin, H.L.

1988-10-25

An advanced servo manipulator has modular parts. Modular motor members drive individual input gears to control shoulder roll, shoulder pitch, elbow pitch, wrist yaw, wrist pitch, wrist roll, and tong spacing. The modules include a support member, a shoulder module for controlling shoulder roll, and a sleeve module attached to the shoulder module in fixed relation thereto. The shoulder roll sleeve module has an inner cylindrical member rotatable relative to the outer cylindrical member, and upon which a gear pod assembly is mounted. A plurality of shafts are driven by the gears, which are in turn driven by individual motor modules to transmit rotary power to control elbow pitch as well as to provide four different rotary shafts across the bendable elbow joint to supply rotary motive power to a wrist member and tong member. 41 figs.

Advanced servo manipulator

DOEpatents

Holt, William E.; Kuban, Daniel P.; Martin, H. Lee

1988-01-01

An advanced servo manipulator has modular parts. Modular motor members drive individual input gears to control shoulder roll, shoulder pitch, elbow pitch, wrist yaw, wrist pitch, wrist roll, and tong spacing. The modules include a support member, a shoulder module for controlling shoulder roll, and a sleeve module attached to the shoulder module in fixed relation thereto. The shoulder roll sleeve module has an inner cylindrical member rotatable relative to the outer cylindrical member, and upon which a gear pod assembly is mounted. A plurality of shafts are driven by the gears, which are in turn driven by individual motor modules to transmit rotary power to control elbow pitch as well as to provide four different rotary shafts across the bendable elbow joint to supply rotary motive power to a wrist member and tong member.

The Design and Implementation of NASA's Advanced Flight Computing Module

NASA Technical Reports Server (NTRS)

Alkakaj, Leon; Straedy, Richard; Jarvis, Bruce

1995-01-01

This paper describes a working flight computer Multichip Module developed jointly by JPL and TRW under their respective research programs in a collaborative fashion. The MCM is fabricated by nCHIP and is packaged within a 2 by 4 inch Al package from Coors. This flight computer module is one of three modules under development by NASA's Advanced Flight Computer (AFC) program. Further development of the Mass Memory and the programmable I/O MCM modules will follow. The three building block modules will then be stacked into a 3D MCM configuration. The mass and volume of the flight computer MCM achieved at 89 grams and 1.5 cubic inches respectively, represent a major enabling technology for future deep space as well as commercial remote sensing applications.

Adaptive Modulation for DFIG and STATCOM With High-Voltage Direct Current Transmission.

PubMed

Tang, Yufei; He, Haibo; Ni, Zhen; Wen, Jinyu; Huang, Tingwen

2016-08-01

This paper develops an adaptive modulation approach for power system control based on the approximate/adaptive dynamic programming method, namely, the goal representation heuristic dynamic programming (GrHDP). In particular, we focus on the fault recovery problem of a doubly fed induction generator (DFIG)-based wind farm and a static synchronous compensator (STATCOM) with high-voltage direct current (HVDC) transmission. In this design, the online GrHDP-based controller provides three adaptive supplementary control signals to the DFIG controller, STATCOM controller, and HVDC rectifier controller, respectively. The mechanism is to observe the system states and their derivatives and then provides supplementary control to the plant according to the utility function. With the GrHDP design, the controller can adaptively develop an internal goal representation signal according to the observed power system states, therefore, to achieve more effective learning and modulating. Our control approach is validated on a wind power integrated benchmark system with two areas connected by HVDC transmission lines. Compared with the classical direct HDP and proportional integral control, our GrHDP approach demonstrates the improved transient stability under system faults. Moreover, experiments under different system operating conditions with signal transmission delays are also carried out to further verify the effectiveness and robustness of the proposed approach.

The extraordinary joint material of an articulated coralline alga. II. Modeling the structural basis of its mechanical properties.

PubMed

Denny, Mark W; King, Felicia A

2016-06-15

By incorporating joints into their otherwise rigid fronds, erect coralline algae have evolved to be as flexible as other seaweeds, which allows them to thrive - and even dominate space - on wave-washed shores around the globe. However, to provide the required flexibility, the joint tissue of Calliarthron cheilosporioides, a representative articulated coralline alga, relies on an extraordinary tissue that is stronger, more extensible and more fatigue resistant than that of other algae. Here, we used the results from recent experiments to parameterize a conceptual model that links the microscale architecture of cell walls to the adaptive mechanical properties of joint tissue. Our analysis suggests that the theory of discontinuous fiber-wound composite materials (with cellulose fibrils as the fibers and galactan gel as the matrix) can explain key aspects of the material's mechanics. In particular, its adaptive viscoelastic behavior can be characterized by two, widely separated time constants. We speculate that the short time constant (∼14 s) results from the viscous response of the matrix to the change in cell-wall shape as a joint is stretched, a response that allows the material both to remain flexible and to dissipate energy as a frond is lashed by waves. We propose that the long time constant (∼35 h), is governed by the shearing of the matrix between cellulose fibrils. The resulting high apparent viscosity ensures that joints avoid accumulating lethal deformation in the course of a frond's lifetime. Our synthesis of experimental measurements allows us to draw a chain of mechanistic inference from molecules to cell walls to fronds and community ecology. © 2016. Published by The Company of Biologists Ltd.

Joint Dictionary Learning for Multispectral Change Detection.

PubMed

Lu, Xiaoqiang; Yuan, Yuan; Zheng, Xiangtao

2017-04-01

Change detection is one of the most important applications of remote sensing technology. It is a challenging task due to the obvious variations in the radiometric value of spectral signature and the limited capability of utilizing spectral information. In this paper, an improved sparse coding method for change detection is proposed. The intuition of the proposed method is that unchanged pixels in different images can be well reconstructed by the joint dictionary, which corresponds to knowledge of unchanged pixels, while changed pixels cannot. First, a query image pair is projected onto the joint dictionary to constitute the knowledge of unchanged pixels. Then reconstruction error is obtained to discriminate between the changed and unchanged pixels in the different images. To select the proper thresholds for determining changed regions, an automatic threshold selection strategy is presented by minimizing the reconstruction errors of the changed pixels. Adequate experiments on multispectral data have been tested, and the experimental results compared with the state-of-the-art methods prove the superiority of the proposed method. Contributions of the proposed method can be summarized as follows: 1) joint dictionary learning is proposed to explore the intrinsic information of different images for change detection. In this case, change detection can be transformed as a sparse representation problem. To the authors' knowledge, few publications utilize joint learning dictionary in change detection; 2) an automatic threshold selection strategy is presented, which minimizes the reconstruction errors of the changed pixels without the prior assumption of the spectral signature. As a result, the threshold value provided by the proposed method can adapt to different data due to the characteristic of joint dictionary learning; and 3) the proposed method makes no prior assumption of the modeling and the handling of the spectral signature, which can be adapted to different data.

Strengthening public health laboratory capacity in Thailand for International Health Regulations (IHR) (2005)

PubMed Central

Peruski, Anne Harwood; Birmingham, Maureen; Tantinimitkul, Chawalit; Chungsamanukool, Ladawan; Chungsamanukool, Preecha; Guntapong, Ratigorn; Pulsrikarn, Chaiwat; Saengklai, Ladapan; Supawat, Krongkaew; Thattiyaphong, Aree; Wongsommart, Duangdao; Wootta, Wattanapong; Nikiema, Abdoulaye; Pierson, Antoine; Peruski, Leonard F; Liu, Xin; Rayfield, Mark A

2015-01-01

Introduction Thailand conducted a national laboratory assessment of core capacities related to the International Health Regulations (IHR) (2005), and thereby established a baseline to measure future progress. The assessment was limited to public laboratories found within the Thai Bureau of Quality and Safety of Food, National Institute of Health and regional medical science centres. Methods The World Health Organization (WHO) laboratory assessment tool was adapted to Thailand through a participatory approach. This adapted version employed a specific scoring matrix and comprised 16 modules with a quantitative output. Two teams jointly performed the on-site assessments in December 2010 over a two-week period, in 17 public health laboratories in Thailand. The assessment focused on the capacity to identify and accurately detect pathogens mentioned in Annex 2 of the IHR (2005) in a timely manner, as well as other public health priority pathogens for Thailand. Results Performance of quality management, budget and finance, data management and communications was considered strong (>90%); premises quality, specimen collection, biosafety, public health functions, supplies management and equipment availability were judged as very good (>70% but ≤90%); while microbiological capacity, staffing, training and supervision, and information technology needed improvement (>60% but ≤70%). Conclusions This assessment is a major step in Thailand towards development of an optimized and standardized national laboratory network for the detection and reporting of infectious disease that would be compliant with IHR (2005). The participatory strategy employed to adapt an international tool to the Thai context can also serve as a model for use by other countries in the Region. The participatory approach probably ensured better quality and ownership of the results, while providing critical information to help decision-makers determine where best to invest finite resources. PMID:26693144

Specific Stimuli Induce Specific Adaptations: Sensorimotor Training vs. Reactive Balance Training

PubMed Central

Freyler, Kathrin; Krause, Anne; Gollhofer, Albert; Ritzmann, Ramona

2016-01-01

Typically, balance training has been used as an intervention paradigm either as static or as reactive balance training. Possible differences in functional outcomes between the two modalities have not been profoundly studied. The objective of the study was to investigate the specificity of neuromuscular adaptations in response to two balance intervention modalities within test and intervention paradigms containing characteristics of both profiles: classical sensorimotor training (SMT) referring to a static ledger pivoting around the ankle joint vs. reactive balance training (RBT) using externally applied perturbations to deteriorate body equilibrium. Thirty-eight subjects were assigned to either SMT or RBT. Before and after four weeks of intervention training, postural sway and electromyographic activities of shank and thigh muscles were recorded and co-contraction indices (CCI) were calculated. We argue that specificity of training interventions could be transferred into corresponding test settings containing properties of SMT and RBT, respectively. The results revealed that i) postural sway was reduced in both intervention groups in all test paradigms; magnitude of changes and effect sizes differed dependent on the paradigm: when training and paradigm coincided most, effects were augmented (P<0.05). ii) These specificities were accompanied by segmental modulations in the amount of CCI, with a greater reduction within the CCI of thigh muscles after RBT compared to the shank muscles after SMT (P<0.05). The results clearly indicate the relationship between test and intervention specificity in balance performance. Hence, specific training modalities of postural control cause multi-segmental and context-specific adaptations, depending upon the characteristics of the trained postural strategy. In relation to fall prevention, perturbation training could serve as an extension to SMT to include the proximal segment, and thus the control of structures near to the body’s centre of mass, into training. PMID:27911944

Method and apparatus for adaptive force and position control of manipulators

NASA Technical Reports Server (NTRS)

Seraji, Homayoun (Inventor)

1989-01-01

The present invention discloses systematic methods and apparatus for the design of real time controllers. Real-time control employs adaptive force/position by use of feedforward and feedback controllers, with the feedforward controller being the inverse of the linearized model of robot dynamics and containing only proportional-double-derivative terms is disclosed. The feedback controller, of the proportional-integral-derivative type, ensures that manipulator joints follow reference trajectories and the feedback controller achieves robust tracking of step-plus-exponential trajectories, all in real time. The adaptive controller includes adaptive force and position control within a hybrid control architecture. The adaptive controller, for force control, achieves tracking of desired force setpoints, and the adaptive position controller accomplishes tracking of desired position trajectories. Circuits in the adaptive feedback and feedforward controllers are varied by adaptation laws.

Compact storage of medical images with patient information.

PubMed

Acharya, R; Anand, D; Bhat, S; Niranjan, U C

2001-12-01

Digital watermarking is a technique of hiding specific identification data for copyright authentication. This technique is adapted here for interleaving patient information with medical images to reduce storage and transmission overheads. The text data are encrypted before interleaving with images to ensure greater security. The graphical signals are compressed and subsequently interleaved with the image. Differential pulse-code-modulation and adaptive-delta-modulation techniques are employed for data compression, and encryption and results are tabulated for a specific example.

Membrane module assembly

DOEpatents

Kaschemekat, J.

1994-03-15

A membrane module assembly is described which is adapted to provide a flow path for the incoming feed stream that forces it into prolonged heat-exchanging contact with a heating or cooling mechanism. Membrane separation processes employing the module assembly are also disclosed. The assembly is particularly useful for gas separation or pervaporation. 2 figures.

High quality adaptive optics zoom with adaptive lenses

NASA Astrophysics Data System (ADS)

Quintavalla, M.; Santiago, F.; Bonora, S.; Restaino, S.

2018-02-01

We present the combined use of large aperture adaptive lens with large optical power modulation with a multi actuator adaptive lens. The Multi-actuator Adaptive Lens (M-AL) can correct up to the 4th radial order of Zernike polynomials, without any obstructions (electrodes and actuators) placed inside its clear aperture. We demonstrated that the use of both lenses together can lead to better image quality and to the correction of aberrations of adaptive optics optical systems.

Method and apparatus for calibrating multi-axis load cells in a dexterous robot

NASA Technical Reports Server (NTRS)

Wampler, II, Charles W. (Inventor); Platt, Jr., Robert J. (Inventor)

2012-01-01

A robotic system includes a dexterous robot having robotic joints, angle sensors adapted for measuring joint angles at a corresponding one of the joints, load cells for measuring a set of strain values imparted to a corresponding one of the load cells during a predetermined pose of the robot, and a host machine. The host machine is electrically connected to the load cells and angle sensors, and receives the joint angle values and strain values during the predetermined pose. The robot presses together mating pairs of load cells to form the poses. The host machine executes an algorithm to process the joint angles and strain values, and from the set of all calibration matrices that minimize error in force balance equations, selects the set of calibration matrices that is closest in a value to a pre-specified value. A method for calibrating the load cells via the algorithm is also provided.

S-cone discrimination in the presence of two adapting fields: data and model

PubMed Central

Cao, Dingcai

2014-01-01

This study investigated S-cone discrimination using a test annulus surrounded by an inner and outer adapting field with systematic manipulation of the adapting l = L/(L + M) or s = S/(L + M) chromaticities. The results showed that different adapting l chromaticities altered S-cone discrimination for a high adapting s chromaticity due to parvocellular input to the koniocellular pathway. In addition, S-cone discrimination was determined by the combined spectral signals arising from both adapting fields. The “white” adapting field or an adapting field with a different l chromaticity from the other fields was more likely to have a stronger influence on discrimination thresholds. These results indicated that the two cardinal axes are not independent in S-cone discrimination, and the two adapting fields jointly contribute to S-cone discrimination through a cortical summation mechanism. PMID:24695204

Fires. A Joint Publication for U.S. Artillery Professionals. January - February 2012

DTIC Science & Technology

2012-01-01

support). Just as a musician has to learn the fundamentals of his instrument and how to produce the desired melody, young officers must learn the...Approved for public release; distribution is unlimited. • Headquarters, Department of the Army • PB644-12-1 Adapting young leaders through learning...progress, developments and best use in campaigns; cultivates a common understanding of the power, limitations and application of joint Fires, both

Indoor unit for electric heat pump

DOEpatents

Draper, R.; Lackey, R.S.; Fagan, T.J. Jr.; Veyo, S.E.; Humphrey, J.R.

1984-05-22

An indoor unit for an electric heat pump is provided in modular form including a refrigeration module, an air mover module, and a resistance heat package module, the refrigeration module including all of the indoor refrigerant circuit components including the compressor in a space adjacent the heat exchanger, the modules being adapted to be connected to air flow communication in several different ways as shown to accommodate placement of the unit in various orientations. 9 figs.

The transmission of low frequency medical data using delta modulation techniques.

NASA Technical Reports Server (NTRS)

Arndt, G. D.; Dawson, C. T.

1972-01-01

The transmission of low-frequency medical data using delta modulation techniques is described. The delta modulators are used to distribute the low-frequency data into the passband of the telephone lines. Both adaptive and linear delta modulators are considered. Optimum bit rates to minimize distortion and intersymbol interference are discussed. Vibrocardiographic waves are analyzed as a function of bit rate and delta modulator configuration to determine their reproducibility for medical evaluation.

Military Curricula for Vocational & Technical Education. Basic Electricity and Electronics. CANTRAC A-100-0010. Module 21: Basic Transistor Theory; Module 21T: Multi-Element Vacuum Tubes. Study Booklet.

ERIC Educational Resources Information Center

Chief of Naval Education and Training Support, Pensacola, FL.

This set of individualized learning modules on transistor theory is one in a series of modules for a course in basic electricity and electronics. The course is one of a number of military-developed curriculum packages selected for adaptation to vocational instructional and curriculum development in a civilian setting. Two modules are included in…

Adaptive Units of Learning and Educational Videogames

ERIC Educational Resources Information Center

Moreno-Ger, Pablo; Thomas, Pilar Sancho; Martinez-Ortiz, Ivan; Sierra, Jose Luis; Fernandez-Manjon, Baltasar

2007-01-01

In this paper, we propose three different ways of using IMS Learning Design to support online adaptive learning modules that include educational videogames. The first approach relies on IMS LD to support adaptation procedures where the educational games are considered as Learning Objects. These games can be included instead of traditional content…

Water System Adaptation To Hydrological Changes: Module 9, Water System Resilience and Security under Hydrologic Variability and Uncertainty

EPA Science Inventory

This course will introduce students to the fundamental principles of water system adaptation to hydrological changes, with emphasis on data analysis and interpretation, technical planning, and computational modeling. Starting with real-world scenarios and adaptation needs, the co...

Application of Pi Preform Composite Joints in Fabrication of NASA Composite Crew Module Demonstration Structure

NASA Technical Reports Server (NTRS)

Higgins, John E.; Pelham, Larry

2008-01-01

This paper will describe unique and extensive use of pre-woven and impregnated pi cross-sections in fabrication of a carbon composite demonstration structure for the Composite Crew Module (CCM) Program. The program is managed by the NASA Safety and Engineering Center with participants from ten NASA Centers and AFRL. Multiple aerospace contractors are participating in the design development, tooling and fabrication effort as well. The goal of the program is to develop an agency wide design team for composite habitable spacecraft. The specific goals for this development project are: a) To gain hands on experience in design, building and testing a composite crew module. b) To validate key assumptions by resolving composite spacecraft design details through fabrication and testing of hardware. This paper will focus on the design and fabrication issues supporting selection of the Lockheed Martin patented Pi pre-form to provide sound composite joints a numerous locations in the structure. This abstract is based on Preliminary Design data. The final design will continue to evolve through the fall of 2007 with fabrication mostly completed by conference date.

Coherently coupled high-power fiber arrays

NASA Astrophysics Data System (ADS)

Anderegg, Jesse; Brosnan, Stephen; Cheung, Eric; Epp, Paul; Hammons, Dennis; Komine, Hiroshi; Weber, Mark; Wickham, Michael

2006-02-01

A four-element fiber array has demonstrated 470 watts of coherently phased, linearly polarized light energy in a single far-field spot. Each element consists of a single-mode fiber-amplifier chain. Phase control of each element is achieved with a Lithium-Niobate phase modulator. A master laser provides a linearly polarized, narrow linewidth signal that is split into five channels. Four channels are individually amplified using polarization maintaining fiber power amplifiers. The fifth channel is used as a reference arm. It is frequency shifted and then combined interferometrically with a portion of each channel's signal. Detectors sense the heterodyne modulation signal, and an electronics circuit measures the relative phase for each channel. Compensating adjustments are then made to each channel's phase modulator. This effort represents the results of a multi-year effort to achieve high power from a single element fiber amplifier and to understand the important issues involved in coherently combining many individual elements to obtain sufficient optical power for directed energy weapons. Northrop Grumman Corporation and the High Energy Laser Joint Technology Office jointly sponsored this work.

Development of new vibration energy flow analysis software and its applications to vehicle systems

NASA Astrophysics Data System (ADS)

Kim, D.-J.; Hong, S.-Y.; Park, Y.-H.

2005-09-01

The Energy flow analysis (EFA) offers very promising results in predicting the noise and vibration responses of system structures in medium-to-high frequency ranges. We have developed the Energy flow finite element method (EFFEM) based software, EFADSC++ R4, for the vibration analysis. The software can analyze the system structures composed of beam, plate, spring-damper, rigid body elements and many other components developed, and has many useful functions in analysis. For convenient use of the software, the main functions of the whole software are modularized into translator, model-converter, and solver. The translator module makes it possible to use finite element (FE) model for the vibration analysis. The model-converter module changes FE model into energy flow finite element (EFFE) model, and generates joint elements to cover the vibrational attenuation in the complex structures composed of various elements and can solve the joint element equations by using the wave tra! nsmission approach very quickly. The solver module supports the various direct and iterative solvers for multi-DOF structures. The predictions of vibration for real vehicles by using the developed software were performed successfully.

Strength Variation of Parachute Joints

NASA Technical Reports Server (NTRS)

Mollmann, Catherine

2017-01-01

A parachute joint is defined as a location where a component is sewn or connected to another component. During the design and developmental phase of a parachute system, the joints for each structural component are isolated and tested through a process called seam and joint testing. The objective of seam and joint testing is to determine the degradation on a single component due to interaction with other components; this data is then used when calculating the margin of safety for that component. During the engineering developmental phase of CPAS (Capsule Parachute Assembly System), the parachute system for the NASA Orion Crew Module, testing was completed for every joint of the six subsystems: the four parachutes (main, drogue, pilot, and FBCP [forward bay cover parachute]), the retention release bridle, and the retention panels. The number of joint tests for these subsystems totaled 92, which provides a plethora of data and results for further analysis. In this paper, the data and results of these seam and joint tests are examined to determine the effects, if any, of different operators and sewing machines on the strength of parachute joints. Other variables are also studied to determine their effect on joint strength, such as joint complexity, joint strength magnitude, material type, and material construction. Findings reveal that an optimally-run seam and joint test program could result in an increased understanding of the structure of the parachute; this should lead to a parachute built with optimal components, potentially saving system weight and volume.

A Novel EphA4 Based Small Molecule Based Therapeutic Strategy for Prevention and Treatment of Post Traumatic Osteoarthritis

DTIC Science & Technology

2016-09-01

surface of the joint. During joint inflammation, e.g., rheumatoid arthritis , synovial fibroblasts take on an aggressive, invasive phenotype...binding proteins) is expressed at site of invasion in rheumatoid arthritis synovium and modulates production MMPs, and because increased S100A4 protein...fibroblast behavior contributing to the pathogenesis of chronic autoinflammatory diseases such as rheumatoid arthritis . Col2α1 mRNA level was measured

Fixed or adapted conditioning intensity for repeated conditioned pain modulation.

PubMed

Hoegh, M; Petersen, K K; Graven-Nielsen, T

2017-12-29

Aims Conditioned pain modulation (CPM) is used to assess descending pain modulation through a test stimulation (TS) and a conditioning stimulation (CS). Due to potential carry-over effects, sequential CPM paradigms might alter the intensity of the CS, which potentially can alter the CPM-effect. This study aimed to investigate the difference between a fixed and adaptive CS intensity on CPM-effect. Methods On the dominant leg of 20 healthy subjects the cuff pressure detection threshold (PDT) was recorded as TS and the pain tolerance threshold (PTT) was assessed on the non-dominant leg for estimating the CS. The difference in PDT before and during CS defined the CPM-effect. The CPM-effect was assessed four times using a CS with intensities of 70% of baseline PTT (fixed) or 70% of PTT measured throughout the session (adaptive). Pain intensity of the conditioning stimulus was assessed on a numeric rating scale (NRS). Data were analyzed with repeated-measures ANOVA. Results No difference was found comparing the four PDTs assessed before CSs for the fixed and the adaptive paradigms. The CS pressure intensity for the adaptive paradigm was increasing during the four repeated assessments (P < 0.01). The pain intensity was similar during the fixed (NRS: 5.8±0.5) and the adjusted paradigm (NRS: 6.0±0.4). The CPM-effect was higher using the fixed condition compared with the adaptive condition (P < 0.05). Conclusions The current study found that sequential CPM paradigms using a fixed conditioning stimulus produced an increased CPM-effect compared with adaptive and increasing conditioning intensities.

The Motor and the Brake of the Trailing Leg in Human Walking: Leg Force Control Through Ankle Modulation and Knee Covariance

PubMed Central

Toney, Megan E.; Chang, Young-Hui

2016-01-01

Human walking is a complex task, and we lack a complete understanding of how the neuromuscular system organizes its numerous muscles and joints to achieve consistent and efficient walking mechanics. Focused control of select influential task-level variables may simplify the higher-level control of steady state walking and reduce demand on the neuromuscular system. As trailing leg power generation and force application can affect the mechanical efficiency of step-to-step transitions, we investigated how joint torques are organized to control leg force and leg power during human walking. We tested whether timing of trailing leg force control corresponded with timing of peak leg power generation. We also applied a modified uncontrolled manifold analysis to test whether individual or coordinated joint torque strategies most contributed to leg force control. We found that leg force magnitude was adjusted from step-to-step to maintain consistent leg power generation. Leg force modulation was primarily determined by adjustments in the timing of peak ankle plantar-flexion torque, while knee torque was simultaneously covaried to dampen the effect of ankle torque on leg force. We propose a coordinated joint torque control strategy in which the trailing leg ankle acts as a motor to drive leg power production while trailing leg knee torque acts as a brake to refine leg power production. PMID:27334888

On-line upgrade of program modules using AdaPT

NASA Technical Reports Server (NTRS)

Waldrop, Raymond S.; Volz, Richard A.; Smith, Gary W.; Goldsack, Stephen J.; Holzbach-Valero, A. A.

1993-01-01

One purpose of our research is the investigation of the effectiveness and expressiveness of AdaPT, a set of language extensions to Ada 83, for distributed systems. As a part of that effort, we are now investigating the subject of replacing, e.g. upgrading, software modules while the software system remains in operation. The AdaPT language extensions provide a good basis for this investigation for several reasons: they include the concept of specific, self-contained program modules which can be manipulated; support for program configuration is included in the language; and although the discussion will be in terms of the AdaPT language, the AdaPT to Ada 83 conversion methodology being developed as another part of this project will provide a basis for the application of our findings to Ada 83 and Ada 9X systems. The purpose of this investigation is to explore the basic mechanisms of the replacement process. With this purpose in mind, we will avoid including issues whose presence would obscure these basic mechanisms by introducing additional, unrelated concerns. Thus, while replacement in the presence of real-time deadlines, heterogeneous systems, and unreliable networks is certainly a topic of interest, we will first gain an understanding of the basic processes in the absence of such concerns. The extension of the replacement process to more complex situations can be made later. A previous report established an overview of the module replacement problem, a taxonomy of the various aspects of the replacement process, and a solution to one case in the replacement taxonomy. This report provides solutions to additional cases in the replacement process taxonomy: replacement of partitions with state and replacement of nodes. The solutions presented here establish the basic principles for module replacement. Extension of these solutions to other more complicated cases in the replacement taxonomy is direct, though requiring substantial work beyond the available funding.

ASTP crewmen have a meal during training session at JSC

NASA Technical Reports Server (NTRS)

1975-01-01

Three ASTP crewmen have a meal in the Apollo Command Module trainer in bldg 35 during Apollo Soyuz Test Project (ASTP) joint crew training at JSC. They are, left to right, Cosmonaut Aleksay A. Leonov, commander of the Soviet ASTP first (prime) crew; Astronaut Donald K. Slayton, docking module pilot of the American ASTP prime crew; and Astronaut Thomas P. Stafford, commander of the American ASTP prime crew.

ASTP Apollo Command Module nears touchdown in Central Pacific

NASA Image and Video Library

1975-07-24

S75-29719 (24 July 1975) --- The ASTP Apollo Command Module, with astronauts Thomas P. Stafford, Vance D. Brand and Donald K. Slayton aboard, nears a touchdown in the Central Pacific Ocean to conclude the historic joint U.S.-USSR Apollo-Soyuz Test Project docking mission in Earth orbit. The spacecraft splashed down in the Hawaiian Islands area at 4:18 p.m. (CDT), July 24, 1975.

Modulation of cytokine-induced prostaglandin E₂ production in cultures of articular chondrocytes obtained from carpal joints of camels (Camelus dromedarius).

PubMed

Frondoza, Carmelita G; Heinecke, Lowella F; Grzanna, Mark W; Au, Angela Y; Ownby, Stacy L

2011-01-01

To determine whether camel articular chondrocytes can be maintained in tissue culture without phenotype loss and whether the response to cytokine stimulation can be modulated. Cartilage from 4 carpal joints of healthy adult dromedary camels (Camelus dromedarius). Chondrocytes were evaluated for type II collagen and aggrecan production They were incubated with control media or with 2 test mixtures (alone and then in combination) that have anti-inflammatory activity (avocado-soybean unsaponifiables, glucosamine, and chondroitin sulfate [ie, ASU + GLU + CS] and pentosan polysulfate and N-acetyl glucosamine [ie, PPS + NG]). Cells were then stimulated with interleukin-1β and tumor necrosis factor-α to determine prostaglandin (PG) E₂ production and nuclear factor (NF)-κB activation. Chondrocytes proliferated in media used for propagating equine chondrocytes; they produced type II collagen and aggrecan. Cytokine stimulation induced PGE₂ production and translocation of NF-κB. Incubation with each test mixture significantly inhibited PGE₂ production. The combination of ASU + GLU + CS and PPS + NG significantly potentiated PGE₂ inhibition and disrupted NF-κB translocation, compared with effects for either mixture alone. Chondrocytes proliferated without loss of the cartilage phenotype. Responses to cytokines were significantly inhibited by the mixtures of ASU + GLU + CS and PPS + NG, which indicated that this response can be modulated. This culture technique can be used to study the functional properties of camel chondrocytes and identify agents that may potentially be used to treat and manage joint inflammation.

Interdisciplinary Collaboration in the Choice of an Adapted Mobility Device for a Child with Cerebral Palsy and Visual Impairment.

ERIC Educational Resources Information Center

Glanzman, Allan; Ducret, Walter

2003-01-01

To select an adapted mobility device for a 5-year-old boy with blindness and spastic diplegic cerebral palsy, a multidisciplinary team used 8-millimeter videography to evaluate the subject's joint angle during ambulation with one of three canes and with no cane. The I-style cane provided optimal posture and gait pattern. (Contains references.) (CR)

A Systematic Review of the Literature on Parenting of Young Children with Visual Impairments and the Adaptions for Video-Feedback Intervention to Promote Positive Parenting (VIPP).

PubMed

van den Broek, Ellen G C; van Eijden, Ans J P M; Overbeek, Mathilde M; Kef, Sabina; Sterkenburg, Paula S; Schuengel, Carlo

2017-01-01

Secure parent-child attachment may help children to overcome the challenges of growing up with a visual or visual-and-intellectual impairment. A large literature exists that provides a blueprint for interventions that promote parental sensitivity and secure attachment. The Video-feedback Intervention to promote Positive Parenting (VIPP) is based on that blueprint. While it has been adapted to several specific at risk populations, children with visual impairment may require additional adjustments. This study aimed to identify the themes that should be addressed in adapting VIPP and similar interventions. A Delphi-consultation was conducted with 13 professionals in the field of visual impairment to select the themes for relationship-focused intervention. These themes informed a systematic literature search. Interaction, intersubjectivity, joint attention, exploration, play and specific behavior were the themes mentioned in the Delphi-group. Paired with visual impairment or vision disorders, infants or young children (and their parents) the search yielded 74 articles, making the six themes for intervention adaptation more specific and concrete. The rich literature on six visual impairment specific themes was dominated by the themes interaction, intersubjectivity, and joint attention. These themes need to be addressed in adapting intervention programs developed for other populations, such as VIPP which currently focuses on higher order constructs of sensitivity and attachment.

Adapt-Mix: learning local genetic correlation structure improves summary statistics-based analyses

PubMed Central

Park, Danny S.; Brown, Brielin; Eng, Celeste; Huntsman, Scott; Hu, Donglei; Torgerson, Dara G.; Burchard, Esteban G.; Zaitlen, Noah

2015-01-01

Motivation: Approaches to identifying new risk loci, training risk prediction models, imputing untyped variants and fine-mapping causal variants from summary statistics of genome-wide association studies are playing an increasingly important role in the human genetics community. Current summary statistics-based methods rely on global ‘best guess’ reference panels to model the genetic correlation structure of the dataset being studied. This approach, especially in admixed populations, has the potential to produce misleading results, ignores variation in local structure and is not feasible when appropriate reference panels are missing or small. Here, we develop a method, Adapt-Mix, that combines information across all available reference panels to produce estimates of local genetic correlation structure for summary statistics-based methods in arbitrary populations. Results: We applied Adapt-Mix to estimate the genetic correlation structure of both admixed and non-admixed individuals using simulated and real data. We evaluated our method by measuring the performance of two summary statistics-based methods: imputation and joint-testing. When using our method as opposed to the current standard of ‘best guess’ reference panels, we observed a 28% decrease in mean-squared error for imputation and a 73.7% decrease in mean-squared error for joint-testing. Availability and implementation: Our method is publicly available in a software package called ADAPT-Mix available at https://github.com/dpark27/adapt_mix. Contact: noah.zaitlen@ucsf.edu PMID:26072481

Military Curricula for Vocational & Technical Education. Basic Electricity and Electronics. CANTRAC A-100-0010. Module 25: Special Devices. Study Booklet.

ERIC Educational Resources Information Center

Chief of Naval Education and Training Support, Pensacola, FL.

This individualized learning module on special devices is one in a series of modules for a course in basic electricity and electronics. The course is one of a number of military-developed curriculum packages selected for adaptation to vocational instructional and curriculum development in a civilian setting. Two lessons are included in the module:…

Advanced adaptive optics technology development

NASA Astrophysics Data System (ADS)

Olivier, Scot S.

2002-02-01

The NSF Center for Adaptive Optics (CfAO) is supporting research on advanced adaptive optics technologies. CfAO research activities include development and characterization of micro-electro-mechanical systems (MEMS) deformable mirror (DM) technology, as well as development and characterization of high-resolution adaptive optics systems using liquid crystal (LC) spatial light modulator (SLM) technology. This paper presents an overview of the CfAO advanced adaptive optics technology development activities including current status and future plans.

Optical communication system performance with tracking error induced signal fading.

NASA Technical Reports Server (NTRS)

Tycz, M.; Fitzmaurice, M. W.; Premo, D. A.

1973-01-01

System performance is determined for an optical communication system using noncoherent detection in the presence of tracking error induced signal fading assuming (1) binary on-off modulation (OOK) with both fixed and adaptive threshold receivers, and (2) binary polarization modulation (BPM). BPM is shown to maintain its inherent 2- to 3-dB advantage over OOK when adaptive thresholding is used, and to have a substantially greater advantage when the OOK system is restricted to a fixed decision threshold.

Skylab checkout operations. [from multiple docking adapter contractor viewpoint

NASA Technical Reports Server (NTRS)

Timmons, K. P.

1973-01-01

The Skylab Program at Kennedy Space Center presented many opportunities for interesting and profound test and checkout experience. It also offered a compilation of challenges and promises for the Center and for the contractors responsible for the various modules making up Skylab. It is very probable that the various contractors had common experiences during the module and combined systems tests, but this paper will discuss those experiences from the viewpoint of the Multiple Docking Adapter contractor. The experience will consider personnel, procedures, and hardware.

Radio Resource Allocation on Complex 4G Wireless Cellular Networks

NASA Astrophysics Data System (ADS)

Psannis, Kostas E.

2015-09-01

In this article we consider the heuristic algorithm which improves step by step wireless data delivery over LTE cellular networks by using the total transmit power with the constraint on users’ data rates, and the total throughput with the constraints on the total transmit power as well as users’ data rates, which are jointly integrated into a hybrid-layer design framework to perform radio resource allocation for multiple users, and to effectively decide the optimal system parameter such as modulation and coding scheme (MCS) in order to adapt to the varying channel quality. We propose new heuristic algorithm which balances the accessible data rate, the initial data rates of each user allocated by LTE scheduler, the priority indicator which signals delay- throughput- packet loss awareness of the user, and the buffer fullness by achieving maximization of radio resource allocation for multiple users. It is noted that the overall performance is improved with the increase in the number of users, due to multiuser diversity. Experimental results illustrate and validate the accuracy of the proposed methodology.

Grounding cognitive control in associative learning.

PubMed

Abrahamse, Elger; Braem, Senne; Notebaert, Wim; Verguts, Tom

2016-07-01

Cognitive control covers a broad range of cognitive functions, but its research and theories typically remain tied to a single domain. Here we outline and review an associative learning perspective on cognitive control in which control emerges from associative networks containing perceptual, motor, and goal representations. Our review identifies 3 trending research themes that are shared between the domains of conflict adaptation, task switching, response inhibition, and attentional control: Cognitive control is context-specific, can operate in the absence of awareness, and is modulated by reward. As these research themes can be envisaged as key characteristics of learning, we propose that their joint emergence across domains is not coincidental but rather reflects a (latent) growth of interest in learning-based control. Associative learning has the potential for providing broad-scaled integration to cognitive control theory, and offers a promising avenue for understanding cognitive control as a self-regulating system without postulating an ill-defined set of homunculi. We discuss novel predictions, theoretical implications, and immediate challenges that accompany an associative learning perspective on cognitive control. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

Adaptation and Mitigation in Agriculture: A Review of Synergies and Tradeoffs and How EO Could Improve Understanding and Outcomes

NASA Astrophysics Data System (ADS)

Barbieri, L.; Wollenberg, E.

2017-12-01

We present a review of the published literature on agricultural adaptation and mitigation, and report on the current evidence as to whether changes in agricultural practices meant to achieve mitigation or adaptation goals can be dual purpose: simultaneously reducing greenhouse gas (GHG) emissions and helping to facilitate adaptation. We characterize the spatio-temporal and system trends in how adaptation and mitigation outcomes are being achieved, and report on the current technical and knowledge gaps that exist and where Earth observations (EO) could improve our understanding. Agriculture contributes 12% GHG emissions globally, roughly one third from the developing world. Nearly 70% of the technical mitigation potential in agriculture sector occurs in these countries, however, while the mitigation potential is high, agricultural productivity also relies heavily on climate factors. With climate change, agricultural systems already, and will increasingly, need to adapt to extreme events and variability in temperatures and precipitation. This underscores the importance of implementing agricultural practices that can both reduce GHG emissions and help facilitate adaptation. Until recently, these objectives have been treated separately, but policy makers are increasingly calling for a joint approach to improve synergies, and avoid tradeoffs. There remain many complications in considering a joint approach: lack of clear conceptual frameworks, knowledge gaps in scientific understanding and evidence associated with adaptation and mitigation outcomes, and the abilities and motivations of stakeholders to consider both objectives. We review 56 peer-reviewed publications and present results from an in-depth analysis to answer two major concerns: to what extent is evidence provided for claims of synergistic outcomes, and what uncertainty surrounds this evidence. Our results show that only 21% of studies empirically measured both mitigation and adaptation outcomes, and claims of synergies are not well substantiated, and evidence is provided at questionable spatio-temporal scales. We highlight information that could be provided by coordinated, comprehensive and sustained EO which could benefit this critical goal of simultaneously achieving agricultural adaptation and mitigation.

Determination of Parachute Joint Factors using Seam and Joint Testing

NASA Technical Reports Server (NTRS)

Mollmann, Catherine

2015-01-01

This paper details the methodology for determining the joint factor for all parachute components. This method has been successfully implemented on the Capsule Parachute Assembly System (CPAS) for the NASA Orion crew module for use in determining the margin of safety for each component under peak loads. Also discussed are concepts behind the joint factor and what drives the loss of material strength at joints. The joint factor is defined as a "loss in joint strength...relative to the basic material strength" that occurs when "textiles are connected to each other or to metals." During the CPAS engineering development phase, a conservative joint factor of 0.80 was assumed for each parachute component. In order to refine this factor and eliminate excess conservatism, a seam and joint testing program was implemented as part of the structural validation. This method split each of the parachute structural joints into discrete tensile tests designed to duplicate the loading of each joint. Breaking strength data collected from destructive pull testing was then used to calculate the joint factor in the form of an efficiency. Joint efficiency is the percentage of the base material strength that remains after degradation due to sewing or interaction with other components; it is used interchangeably with joint factor in this paper. Parachute materials vary in type-mainly cord, tape, webbing, and cloth -which require different test fixtures and joint sample construction methods. This paper defines guidelines for designing and testing samples based on materials and test goals. Using the test methodology and analysis approach detailed in this paper, the minimum joint factor for each parachute component can be formulated. The joint factors can then be used to calculate the design factor and margin of safety for that component, a critical part of the design verification process.

Development and Evaluation of the SUMIT Microcomputer Module Entitled 'Predator Functional Response'.

ERIC Educational Resources Information Center

Shaltz, Mark B.

An experiment was conducted that compared the teaching effectiveness of a computer assisted instructional module and a lecture-discussion. The module, Predator Functional Response (PFR), was developed as part of the SUMIT (Single-concept User-adaptable Microcomputer-based Instructional Technique) project. A class of 30 students was randomly…

COMMAND MODULE (C/M) - SPACECRAFT (S/C) 012 C/M - APOLLO/SATURN (A/S) 204 PREPARATIONS - CAPE

NASA Image and Video Library

1967-01-03

S67-15717 (1967) --- Apollo Spacecraft 012 Command/Service Module is moved from H-134 to east stokes for mating to the Saturn Lunar Module Adapter No. 05 in the Manned Spacecraft Operations Building. S/C 012 will be flown on the Apollo/Saturn 204 mission.

Algorithms for high-speed universal noiseless coding

NASA Technical Reports Server (NTRS)

Rice, Robert F.; Yeh, Pen-Shu; Miller, Warner

1993-01-01

This paper provides the basic algorithmic definitions and performance characterizations for a high-performance adaptive noiseless (lossless) 'coding module' which is currently under separate developments as single-chip microelectronic circuits at two NASA centers. Laboratory tests of one of these implementations recently demonstrated coding rates of up to 900 Mbits/s. Operation of a companion 'decoding module' can operate at up to half the coder's rate. The functionality provided by these modules should be applicable to most of NASA's science data. The hardware modules incorporate a powerful adaptive noiseless coder for 'standard form' data sources (i.e., sources whose symbols can be represented by uncorrelated nonnegative integers where the smaller integers are more likely than the larger ones). Performance close to data entries can be expected over a 'dynamic range' of from 1.5 to 12-15 bits/sample (depending on the implementation). This is accomplished by adaptively choosing the best of many Huffman equivalent codes to use on each block of 1-16 samples. Because of the extreme simplicity of these codes no table lookups are actually required in an implementation, thus leading to the expected very high data rate capabilities already noted.

Culturally Relevant Human Subjects Protection Training: A Case Study in Community-Engaged Research in the United States.

PubMed

Kue, Jennifer; Szalacha, Laura A; Happ, Mary Beth; Crisp, Abigail L; Menon, Usha

2018-02-01

Non-academic members of research teams, such as community members, can perceive traditional human subjects protection training as lacking in cultural relevance. We present a case exemplar of the development of a human subjects protection training for research staff with limited English proficiency and/or no or limited research experience. Seven modules were adapted for language, cultural examples, etc., from the standard Collaborative Institutional Training Initiative (CITI) human subjects protection training. Non-academic research staff completed a day-long training in human subjects protection (six modules) and our research protocol (one module). We assessed comprehension of content with PowerPoint slides and module quizzes. All participants successfully passed each module quiz with ≥ 80% correct. Questions answered incorrectly were discussed before proceeding to the next module. To meet the increasing demand for collaborative community-engaged research with underserved minority populations, human subjects protection training protocols can be adapted successfully to reflect real-world situations and provide culturally relevant materials to help non-academic research staff better understand the importance and necessity of research ethics.

Enhancing performance of LCoS-SLM as adaptive optics by using computer-generated holograms modulation software

NASA Astrophysics Data System (ADS)

Tsai, Chun-Wei; Lyu, Bo-Han; Wang, Chen; Hung, Cheng-Chieh

2017-05-01

We have already developed multi-function and easy-to-use modulation software that was based on LabVIEW system. There are mainly four functions in this modulation software, such as computer generated holograms (CGH) generation, CGH reconstruction, image trimming, and special phase distribution. Based on the above development of CGH modulation software, we could enhance the performance of liquid crystal on silicon - spatial light modulator (LCoSSLM) as similar as the diffractive optical element (DOE) and use it on various adaptive optics (AO) applications. Through the development of special phase distribution, we are going to use the LCoS-SLM with CGH modulation software into AO technology, such as optical microscope system. When the LCOS-SLM panel is integrated in an optical microscope system, it could be placed on the illumination path or on the image forming path. However, LCOS-SLM provides a program-controllable liquid crystal array for optical microscope. It dynamically changes the amplitude or phase of light and gives the obvious advantage, "Flexibility", to the system

Adaptively loaded SP-offset-QAM OFDM for IM/DD communication systems.

PubMed

Zhao, Jian; Chan, Chun-Kit

2017-09-04

In this paper, we propose adaptively loaded set-partitioned offset quadrature amplitude modulation (SP-offset-QAM) orthogonal frequency division multiplexing (OFDM) for low-cost intensity-modulation direct-detection (IM/DD) communication systems. We compare this scheme with multi-band carrier-less amplitude phase modulation (CAP) and conventional OFDM, and demonstrate >40 Gbit/s transmission over 50-km single-mode fiber. It is shown that the use of SP-QAM formats, together with the adaptive loading algorithm specifically designed to this group of formats, results in significant performance improvement for all these three schemes. SP-offset-QAM OFDM exhibits greatly reduced complexity compared to SP-QAM based multi-band CAP, via parallelized implementation and minimized memory length for spectral shaping. On the other hand, this scheme shows better performance than SP-QAM based conventional OFDM at both back-to-back and after transmission. We also characterize the proposed scheme in terms of enhanced tolerance to fiber intra-channel nonlinearity and the potential to increase the communication security. The studies show that adaptive SP-offset-QAM OFDM is a promising IM/DD solution for medium- and long-reach optical access networks and data center connections.

Nutritional strategies to modulate the adaptive response to endurance training.

PubMed

Hawley, John A

2013-01-01

In recent years, advances in molecular biology have allowed scientists to elucidate how endurance exercise training stimulates skeletal muscle remodeling (i.e. promotes mitochondrial biogenesis). A growing field of interest directly arising from our understanding of the molecular bases of training adaptation is how nutrient availability can alter the regulation of many contraction-induced events in muscle in response to endurance exercise. Acutely manipulating substrate availability can exert profound effects on muscle energy stores and patterns of fuel metabolism during exercise, as well as many processes activating gene expression and cell signaling. Accordingly, such interventions when repeated over weeks and months have the potential to modulate numerous adaptive processes in skeletal muscle that ultimately drive the phenotype-specific characteristics observed in highly trained athletes. In this review, the molecular and cellular events that occur in skeletal muscle during and after endurance exercise are discussed and evidence provided to demonstrate that nutrient availability plays an important role in modulating many of the adaptive responses to training. Emphasis is on human studies that have determined the regulatory role of muscle glycogen availability on cell metabolism, endurance training capacity and performance. Copyright © 2013 Nestec Ltd., Vevey/S. Karger AG, Basel.

ASTP crewmen have a meal during training session at JSC

NASA Technical Reports Server (NTRS)

1975-01-01

The American ASTP prime crewmen have a meal with the Soviet ASTP first (prime) crewmen during Apollo Soyuz Test Project (ASTP) joint crew training at JSC. The four are inside the Soyuz Orbital Module mock-up in bldg 35. They are, left to right, Astronaut Donald K. Slayton, docking module pilot of the American crew; Cosmonaut Aleksey A. Leonov, commander of the Soviet crew; Astronaut Thomas P. Stafford, commander of the American crew; and Cosmonaut Valeriy M. Kubasov, engineer on the Soviet crew. The training session simulated activities on the second day in Earth orbit. During the actual mission the other American crewman, Astronaut Vance D. Brand, command module pilot, would be in the Command Module.

Diode lasers for direct application by utilizing a trepanning optic for remote oscillation welding of aluminum and copper

NASA Astrophysics Data System (ADS)

Fritsche, Haro; Müller, Norbert; Ferrario, Fabio; Fetissow, Sebastian; Grohe, Andreas; Hagen, Thomas; Steger, Ronny; Katzemaikat, Tristan; Ashkenasi, David; Gries, Wolfgang

2017-02-01

We report the first direct diode laser module integrated with a trepanning optic for remote oscillation welding. The trepanning optic is assembled with a collimated DirectProcess 900 laser engine. This modular laser is based on single emitters and beam combiners to achieve fiber coupled modules with a beam parameter product or BPP < 8 mm mrad at all power levels up to 1 kW, as well as free space collimated outputs with even lower BPP. The initial design consists in vertically stacking several diodes in the fast axis which leads to a rectangular output of about 100 W with BPP of <3.5 mm*mrad in the fast axis and <5 mm*mrad in the slow axis. Next, further power scaling is accomplished by polarization combining and wavelength multiplexing yielding high optical efficiencies of more than 80% and resulting in a building block module with over 500 W launched into a 100 μm fiber with 0.15 NA. The beam profile of the free space module remains rectangular, with a nearly flat top and conserves the beam parameter product of the original vertical stack without the power loss of fiber coupling. The 500 W building blocks feature a highly flexible emitting wavelength bandwidth. New wavelengths can be configured by simply exchanging parts and without modifying the production process. This design principle provides the option to adapt the wavelength configuration to match a broad set of applications, from the UV to the visible and to the far IR depending on the commercial availability of laser diodes. This opens numerous additional applications like laser pumping, scientific and medical applications, as well as materials processing applications such as cutting and welding of copper aluminum or steel. Furthermore, the module's short lead lengths enable very short pulses. Integrated with electronics, the module's pulse width can be adjusted from micro-seconds to cw mode operation by simple software commands. An optical setup can be directly attached instead of a fiber to the laser module thanks to its modular design. This paper's experimental results are based on a trepanning optic attached to the laser module. Alltogether the setup approximately fits in a shoe box and weighs less than 20 kg which allows for direct mounting onto a 3D-gantry system. The oscillating weld performance of the 500 W direct diode laser utilizing a novel trepanning optic is discussed for its application to aluminum/aluminum and aluminum/copper joints.

Universal Reading Processes Are Modulated by Language and Writing System

ERIC Educational Resources Information Center

Perfetti, Charles A.; Harris, Lindsay N.

2013-01-01

The connections among language, writing system, and reading are part of what confronts a child in learning to read. We examine these connections in addressing how reading processes adapt to the variety of written language and how writing adapts to language. The first adaptation (reading to writing), as evidenced in behavioral and neuroscience…

Not letting the left leg know what the right leg is doing: limb-specific locomotor adaptation to sensory-cue conflict.

PubMed

Durgin, Frank H; Fox, Laura F; Hoon Kim, Dong

2003-11-01

We investigated the phenomenon of limb-specific locomotor adaptation in order to adjudicate between sensory-cue-conflict theory and motor-adaptation theory. The results were consistent with cue-conflict theory in demonstrating that two different leg-specific hopping aftereffects are modulated by the presence of conflicting estimates of self-motion from visual and nonvisual sources. Experiment 1 shows that leg-specific increases in forward drift during attempts to hop in place on one leg while blindfolded vary according to the relationship between visual information and motor activity during an adaptation to outdoor forward hopping. Experiment 2 shows that leg-specific changes in performance on a blindfolded hopping-to-target task are similarly modulated by the presence of cue conflict during adaptation to hopping on a treadmill. Experiment 3 shows that leg-specific aftereffects from hopping additionally produce inadvertent turning during running in place while blindfolded. The results of these experiments suggest that these leg-specific locomotor aftereffects are produced by sensory-cue conflict rather than simple motor adaptation.

MODUL-a multicenter randomized clinical trial of biomarker-driven maintenance therapy following first-line standard induction treatment of metastatic colorectal cancer: an adaptable signal-seeking approach.

PubMed

Schmoll, Hans-Joachim; Arnold, Dirk; de Gramont, Aimery; Ducreux, Michel; Grothey, Axel; O'Dwyer, Peter J; Van Cutsem, Eric; Hermann, Frank; Bosanac, Ivan; Bendahmane, Belguendouz; Mancao, Christoph; Tabernero, Josep

2018-06-01

The old approach of one therapeutic for all patients with mCRC is evolving with a need to target specific molecular aberrations or cell-signalling pathways. Molecular screening approaches and new biomarkers are required to fully characterize tumours, identify patients most likely to benefit, and predict treatment response. MODUL is a signal-seeking trial with a design that is highly adaptable, permitting modification of different treatment cohorts and inclusion of further additional cohorts based on novel evidence on new compounds/combinations that emerge during the study. MODUL is ongoing and its adaptable nature permits timely and efficient recruitment of patients into the most appropriate cohort. Recruitment will take place over approximately 5 years in Europe, Asia, Africa, and South America. The design of MODUL with ongoing parallel/sequential treatment cohorts means that the overall size and duration of the trial can be modified/prolonged based on accumulation of new data. The early success of the current trial suggests that the design may provide definitive leads in a patient-friendly and relatively economical trial structure. Along with other biomarker-driven trials that are currently underway, it is hoped that MODUL will contribute to the continuing evolution of clinical trial design and permit a more 'tailored' approach to the treatment of patients with mCRC.

Frequency-specific attentional modulation in human primary auditory cortex and midbrain.

PubMed

Riecke, Lars; Peters, Judith C; Valente, Giancarlo; Poser, Benedikt A; Kemper, Valentin G; Formisano, Elia; Sorger, Bettina

2018-07-01

Paying selective attention to an audio frequency selectively enhances activity within primary auditory cortex (PAC) at the tonotopic site (frequency channel) representing that frequency. Animal PAC neurons achieve this 'frequency-specific attentional spotlight' by adapting their frequency tuning, yet comparable evidence in humans is scarce. Moreover, whether the spotlight operates in human midbrain is unknown. To address these issues, we studied the spectral tuning of frequency channels in human PAC and inferior colliculus (IC), using 7-T functional magnetic resonance imaging (FMRI) and frequency mapping, while participants focused on different frequency-specific sounds. We found that shifts in frequency-specific attention alter the response gain, but not tuning profile, of PAC frequency channels. The gain modulation was strongest in low-frequency channels and varied near-monotonically across the tonotopic axis, giving rise to the attentional spotlight. We observed less prominent, non-tonotopic spatial patterns of attentional modulation in IC. These results indicate that the frequency-specific attentional spotlight in human PAC as measured with FMRI arises primarily from tonotopic gain modulation, rather than adapted frequency tuning. Moreover, frequency-specific attentional modulation of afferent sound processing in human IC seems to be considerably weaker, suggesting that the spotlight diminishes toward this lower-order processing stage. Our study sheds light on how the human auditory pathway adapts to the different demands of selective hearing. Copyright © 2018 The Authors. Published by Elsevier Inc. All rights reserved.

KSC-01pp1200

NASA Image and Video Library

2001-06-26

KENNEDY SPACE CENTER, Fla. -- The Joint Airlock Module, sporting a NASA logo, is moved toward the payload bay of Space Shuttle Atlantis for mission STS-104. Once installed and activated, the airlock becomes the primary path for International Space Station spacewalk entry and departure using U.S. spacesuits, which are known as Extravehicular Mobility Units, or EMUs. In addition, the Joint Airlock is designed to support the Russian Orlan spacesuit for EVA activity. Launch of Atlantis is scheduled no earlier than July 12 at 5:04 a.m. EDT

Nutritional management of osteoarthritis.

PubMed

Richardson, D C; Schoenherr, W D; Zicker, S C

1997-07-01

Nutrition can influence developmental orthopedic diseases and the inflammatory process of arthritis. Developmental skeletal disease is a group of skeletal abnormalities that primarily affect fast-growing, large-breed dogs. Nutrient excesses (calcium and energy) and rapid growth (overfeeding and excess energy) are known risk factors. Inflammation can be directly or indirectly affected by nutritional influences. A direct effect can be achieved by modulating the immune response and inflammatory process with fatty acids. Weight control can indirectly influence the degenerative joint disease process by reducing the stresses on the joint.

[The usefullness of hyaluronate injection in patients with RA].

PubMed

Saito, Seiji

2003-06-01

In this seminar, we reported the usefulness of hyaluronate injection in clinical application with patients of RA. In basic research areas, however, the mechanisms responsible for the reported beneficial clinical effects of these treatments remain unclear. There is accumulating experimental evidence to show that the receptors of HA, eg, CD-44, accelerate the inflammation of joint. Administration high molecular weight HA may modulate CD-44 sensitive macromolecular in joint inflammation in part to reduce the activity of proteinases such as MMP-9.

Analysis of the load on the knee joint and vertebral column with changes in squatting depth and weight load.

PubMed

Hartmann, Hagen; Wirth, Klaus; Klusemann, Markus

2013-10-01

It has been suggested that deep squats could cause an increased injury risk of the lumbar spine and the knee joints. Avoiding deep flexion has been recommended to minimize the magnitude of knee-joint forces. Unfortunately this suggestion has not taken the influence of the wrapping effect, functional adaptations and soft tissue contact between the back of thigh and calf into account. The aim of this literature review is to assess whether squats with less knee flexion (half/quarter squats) are safer on the musculoskeletal system than deep squats. A search of relevant scientific publications was conducted between March 2011 and January 2013 using PubMed. Over 164 articles were included in the review. There are no realistic estimations of knee-joint forces for knee-flexion angles beyond 50° in the deep squat. Based on biomechanical calculations and measurements of cadaver knee joints, the highest retropatellar compressive forces and stresses can be seen at 90°. With increasing flexion, the wrapping effect contributes to an enhanced load distribution and enhanced force transfer with lower retropatellar compressive forces. Additionally, with further flexion of the knee joint a cranial displacement of facet contact areas with continuous enlargement of the retropatellar articulating surface occurs. Both lead to lower retropatellar compressive stresses. Menisci and cartilage, ligaments and bones are susceptible to anabolic metabolic processes and functional structural adaptations in response to increased activity and mechanical influences. Concerns about degenerative changes of the tendofemoral complex and the apparent higher risk for chondromalacia, osteoarthritis, and osteochondritis in deep squats are unfounded. With the same load configuration as in the deep squat, half and quarter squat training with comparatively supra-maximal loads will favour degenerative changes in the knee joints and spinal joints in the long term. Provided that technique is learned accurately under expert supervision and with progressive training loads, the deep squat presents an effective training exercise for protection against injuries and strengthening of the lower extremity. Contrary to commonly voiced concern, deep squats do not contribute increased risk of injury to passive tissues.

Comparative biomechanical analysis of current microprocessor-controlled prosthetic knee joints.

PubMed

Bellmann, Malte; Schmalz, Thomas; Blumentritt, Siegmar

2010-04-01

To investigate and identify functional differences of 4 microprocessor-controlled prosthetic knee joints (C-Leg, Hybrid Knee [also called Energy Knee], Rheo Knee, Adaptive 2). Tested situations were walking on level ground, on stairs and ramps; additionally, the fall prevention potentials for each design were examined. The measuring technology used included an optoelectronic camera system combined with 2 forceplates as well as a mobile spiroergometric system. The study was conducted in a gait laboratory. Subjects with unilateral transfemoral amputations (N=9; mobility grade, 3-4; age, 22-49y) were tested. Participants were fitted and tested with 4 different microprocessor-controlled knee joints. Static prosthetic alignment, time distance parameters, kinematic and kinetic data and metabolic energy consumption. Compared with the Hybrid Knee and the Adaptive 2, the C-Leg offers clear advantages in the provision of adequate swing phase flexion resistances and terminal extension damping during level walking at various speeds, especially at higher walking speeds. The Rheo Knee provides sufficient terminal extension; however, swing phase flexion resistances seem to be too low. The values for metabolic energy consumption show only slight differences during level walking. The joint resistances generated for descending stairs and ramps relieve the contralateral side to varying degrees. When walking on stairs, safety-relevant technical differences between the investigated joint types can be observed. Designs with adequate internal resistances offer stability advantages when the foot is positioned on the step. Stumble recovery tests reveal that the different knee joint designs vary in their effectiveness in preventing the patient from falling. The patient benefits provided by the investigated electronic prosthetic knee joints differ considerably. The C-Leg appears to offer the amputee greater functional and safety-related advantages than the other tested knee joints. Reduced loading of the contralateral side has been demonstrated during ramp and stair descent. Metabolic energy consumption does not vary significantly between the tested knees. Hence, this parameter seems not to be a suitable criterion for assessing microprocessor-controlled knee components. Copyright 2010 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.

Adaptive output feedback control of flexible-joint robots using neural networks: dynamic surface design approach.

PubMed

Yoo, Sung Jin; Park, Jin Bae; Choi, Yoon Ho

2008-10-01

In this paper, we propose a new robust output feedback control approach for flexible-joint electrically driven (FJED) robots via the observer dynamic surface design technique. The proposed method only requires position measurements of the FJED robots. To estimate the link and actuator velocity information of the FJED robots with model uncertainties, we develop an adaptive observer using self-recurrent wavelet neural networks (SRWNNs). The SRWNNs are used to approximate model uncertainties in both robot (link) dynamics and actuator dynamics, and all their weights are trained online. Based on the designed observer, the link position tracking controller using the estimated states is induced from the dynamic surface design procedure. Therefore, the proposed controller can be designed more simply than the observer backstepping controller. From the Lyapunov stability analysis, it is shown that all signals in a closed-loop adaptive system are uniformly ultimately bounded. Finally, the simulation results on a three-link FJED robot are presented to validate the good position tracking performance and robustness of the proposed control system against payload uncertainties and external disturbances.

Lineshape asymmetry for joint coherent population trapping and three-photon N resonances

NASA Astrophysics Data System (ADS)

Hancox, Cindy; Hohensee, Michael; Crescimanno, Michael; Phillips, David F.; Walsworth, Ronald L.

2008-06-01

We show that a characteristic two photon lineshape asymmetry arises in coherent population trapping (CPT) and three photon (N) resonances because both resonances are simultaneously induced by modulation sidebands in the interrogating laser light. The N resonance is a three-photon resonance in which a two-photon Raman excitation is combined with a resonant optical pumping field. This joint CPT and N resonance can be the dominant source of lineshape distortion, with direct relevance for the operation of miniaturized atomic frequency standards. We present the results of both an experimental study and theoretical treatment of the asymmetry of the joint CPT and N resonance under conditions typical to the operation of an N resonance clock.