scholarly journals Evaluating Internal Model Strength and Performance of Myoelectric Prosthesis Control Strategies

2017 ◽  
Author(s):  
Ahmed W. Shehata ◽  
Erik J. Scheme ◽  
Jonathon W. Sensinger
Keyword(s):  
Internal Model ◽  
Control Strategies ◽  
Model Development ◽  
Myoelectric Control ◽  
Myoelectric Prosthesis ◽  
And Performance ◽  
Prosthesis Control ◽  
Long Term Performance ◽  
Term Performance

AbstractOngoing developments in myoelectric prosthesis control have provided prosthesis users with an assortment of control strategies that vary in reliability and performance. Many studies have focused on improving performance by providing feedback to the user, but have overlooked the effect of this feedback on internal model development, which is key to improving long-term performance. In this work, the strength of internal models developed for two commonly used myoelectric control strategies: raw control with raw feedback (using a regression-based approach), and filtered control with filtered feedback (using a classifier-based approach), were evaluated using two psychometric measures: trial-by-trial adaptation and just-noticeable-difference. The performance of both strategies was also evaluated using a Schmidt’s style target acquisition task. Results obtained from 24 able-bodied subjects showed that although filtered control with filtered feedback had better short-term performance in path efficiency (p < 0.05), raw control with raw feedback resulted in stronger internal model development (p < 0.05), which may lead to better long-term performance. Despite inherent noise in the control signals of the regression controller, these findings suggest that rich feedback associated with regression control may be used to improve human understanding of the myoelectric control system.

scholarly journals Audible Feedback Improves Internal Model Strength and Performance of Myoelectric Prosthesis Control

2018 ◽  
Author(s):  
Ahmed W. Shehata ◽  
Erik J. Scheme ◽  
Jonathon W. Sensinger
Keyword(s):  
Feedback Control ◽  
Internal Model ◽  
Control Strategies ◽  
Short Term ◽  
Augmented Feedback ◽  
Myoelectric Prosthesis ◽  
Prosthetic Devices ◽  
Long Term Performance ◽  
Term Performance

AbstractMyoelectric prosthetic devices are commonly used to help upper limb amputees perform activities of daily living, however amputees still lack the sensory feedback required to facilitate reliable and precise control. Augmented feedback may play an important role in affecting both short-term performance, through real-time regulation, and long-term performance, through the development of stronger internal models. In this work, we investigate the potential tradeoff between controllers that enable better short-term performance and those that provide sufficient feedback to develop a strong internal model. We hypothesize that augmented feedback may be used to mitigate this tradeoff, ultimately improving both short and long-term control. We used psychometric measures to assess the internal model developed while using a filtered myoelectric controller with augmented audio feedback, imitating classification-based control but with augmented regression-based feedback. In addition, we evaluated the short-term performance using a multi degree-of-freedom constrained-time target acquisition task. Results obtained from 24 able-bodied subjects show that an augmented feedback control strategy using audio cues enables the development of a stronger internal model than the filtered control with filtered feedback, and significantly better path efficiency than both raw and filtered control strategies. These results suggest that the use of augmented feedback control strategies may improve both short-term and long-term performance.

Exhumation and performance of an Antarctic composite barrier system after 4 years exposure

2020 ◽  
Vol 57 (8) ◽  
pp. 1130-1152 ◽  
Author(s):  
R.S. McWatters ◽  
R.K. Rowe ◽  
V. Di Battista ◽  
B. Sfiligoj ◽  
D. Wilkins ◽  
...  
Keyword(s):  
High Density Polyethylene ◽  
Soil Samples ◽  
Composite Liner ◽  
Subgrade Soil ◽  
And Performance ◽  
Long Term Performance ◽  
Term Performance ◽  
The Antarctic ◽  
Coarse Gravel

An Antarctic biopile using a composite liner (high-density polyethylene geomembrane (GMB) over a geosynthetic clay liner (GCL)) was constructed on a coarse granular subgrade to contain hydrocarbon-contaminated soil and leachate. The soil was remediated after 4 years and the biopile was decommissioned. The liner was exhumed to assess the properties and performance of the GMB and GCL. There was no significant change in the GMB index properties. Although cobbles and coarse gravel of the subgrade had left indentations in the GMB, implying tensile strains that could impact long-term performance, there were no holes. There was significant variability in the hydration of the GCL (from 10% to 220%) and in the underlying subgrade soil water content (from 5% to 30%). This reflects the complexity of the subgrade and groundwater flow in the Antarctic environment. The exhumed GCL specimens had low hydraulic conductivity (1 × 10−11 to 7 × 10−11 m/s) at 13 kPa. Soil samples from below the composite liner showed no detectable hydrocarbons and confirmed no migration through the barrier. It is concluded that the composite barrier contained the leachate and biopile soil over the 4 years in service in the extreme Antarctic conditions.

The Long-Term Safety and Performance Analyses of the Surface Disposal Facility for the Belgian Category A Waste at Dessel

2013 ◽  
Author(s):  
Wim Cool ◽  
Elise Vermariën ◽  
William Wacquier ◽  
Janez Perko
Keyword(s):  
Radioactive Waste ◽  
Radiological Criteria ◽  
Disposal Facility ◽  
Safety Function ◽  
License Application ◽  
Performance Analyses ◽  
And Performance ◽  
Long Term Performance ◽  
Term Performance

ONDRAF/NIRAS, the Belgian Agency for Radioactive Waste and Enriched Fissile Materials, and its partners have developed long-term safety and performance analyses in the framework of the license application for a surface disposal facility for low level radioactive waste (category A waste) at Dessel, Belgium. This paper focusses on the methodology of the safety assessments and on key results from the application of this methodology. An overview is given (1) of the performance analyses for the containment safety function of the disposal system and (2) of the radiological impact analyses confirming that radiological impacts are below applicable reference values and constraints and leading to radiological criteria for the waste and the facility. In this discussion, multiple indicators for performance and safety are used to illustrate the multi-faceted nature of long-term performance and safety of the surface disposal. This contributes to the multiple lines of reasoning for confidence building that a positive decision to proceed to the next stage of construction is justified.

scholarly journals STRATEGI DAN KINERJA DALAM SISTEM KOMPENSASI

2014 ◽  
Vol 5 (2) ◽  
Author(s):  
Mimin Nur Aisyah
Keyword(s):  
Stock Price ◽  
Compensation System ◽  
Incentive System ◽  
Goal Congruence ◽  
Company Stock ◽  
And Performance ◽  
Line Manager ◽  
Long Term Performance ◽  
Term Performance

Compensation system has been broadly discussed because of its significant role in enhancing productivity dan performance. It able to motivate a goal directed behavior. Compensation system is expected to provide organizational goal congruence. There are several norms that will lead to different reward distribution. In determining what compensation system that should be taken, organization should consider these dimensions: (1) short term vs long term, (2) cash vs equity, and (3) monetary vs non monetary. Strategy and performance play important role in organizational compensation system. Empirical evidences had support the relation between company’s strategy and its incentive system. Strategic orientation has significant effect on incentive system. To intervene the gap between what is actually needed from compensation system and its practices, the design of reward system should be improved through: (1) give reward to managers only if they perform better than competitors, (2) determine the contribution of each business unit to company stock price, and (3) involve the contribution of front line manager and employees in achieving higher shareholder values. Theory has supports the effectiveness of compensation system, but some evidences showed the contrary. The failness of incentive plans to motivate long term performance should drive the organization to improve the design and implementation of the existed system or to create a new and more effective incentive system.

The contrasting moderating effect of exploration on the relationship between stock options/stock ownership and a firm’s long-term performance

2018 ◽  
Vol 56 (9) ◽  
pp. 1956-1968 ◽  
Author(s):  
Gun Jea Yu ◽  
Joonkyum Lee
Keyword(s):  
Stock Options ◽  
Chief Executive ◽  
Moderating Effect ◽  
Stock Ownership ◽  
Content Type ◽  
And Performance ◽  
Long Term Performance ◽  
Term Performance ◽  
The Relationship

Purpose The purpose of this paper is to investigate the contrasting moderating effect of a firm’s exploration on the relationship between the two types of long-term incentives (stock options/stock ownership) for the chief executive officers and a firm’s long-term performance. Even though the two types of incentives are designed to improve long-term performance, the degrees of impact on long-term performance differ. Based on behavioral agency theory, this study theoretically and empirically examines the role of a firm’s exploration on the above relationship. Design/methodology/approach This study used three archival sources to obtain data on stock options, stock ownership, patents and exploration, financial measures, and others. Based on a sample of 1,963 firms in various industries from 1995 to 2006, this study tested the moderating effect of a firm’s exploration on the relationship between stock options/ownership and a firm’s performance. Findings This study reveals the contrasting moderating effect of a firm’s exploration on the relationship between stock options/ownership and a firm’s long-term performance: a positive moderating effect on the relationship between stock options and performance and a negative moderating effect on the relationship between stock ownership and performance. In addition, empirical evidence was added on the inverted U-shaped relationship between stock ownership and a firm’s long-term performance. Originality/value There is little research on a firm’s internal characteristics that strengthen or weaken the effects of stock options and stock ownership on firm performance. This study demonstrates the differential moderating effects of exploration on the relationship between stock options/stock ownership and long-term performance. Such effects of exploration come from the different risk features of stock options and stock ownership. The key implication is that stock options could be more effective than stock ownership to enhance a firm’s long-term performance when a firm has a strong exploration orientation.

scholarly journals Multiday EMG-Based Classification of Hand Motions with Deep Learning Techniques

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2497 ◽  
Author(s):  
Muhammad Zia ur Rehman ◽  
Asim Waris ◽  
Syed Gilani ◽  
Mads Jochumsen ◽  
Imran Niazi ◽  
...  
Keyword(s):  
Myoelectric Control ◽  
Classification Error ◽  
Linear Discriminant ◽  
Upper Limb Prostheses ◽  
Learning Techniques ◽  
Significant Difference ◽  
Improved Performance ◽  
Long Term Performance ◽  
Term Performance

Pattern recognition of electromyography (EMG) signals can potentially improve the performance of myoelectric control for upper limb prostheses with respect to current clinical approaches based on direct control. However, the choice of features for classification is challenging and impacts long-term performance. Here, we propose the use of EMG raw signals as direct inputs to deep networks with intrinsic feature extraction capabilities recorded over multiple days. Seven able-bodied subjects performed six active motions (plus rest), and EMG signals were recorded for 15 consecutive days with two sessions per day using the MYO armband (MYB, a wearable EMG sensor). The classification was performed by a convolutional neural network (CNN) with raw bipolar EMG samples as the inputs, and the performance was compared with linear discriminant analysis (LDA) and stacked sparse autoencoders with features (SSAE-f) and raw samples (SSAE-r) as inputs. CNN outperformed (lower classification error) both LDA and SSAE-r in the within-session, between sessions on same day, between the pair of days, and leave-out one-day evaluation (p < 0.001) analyses. However, no significant difference was found between CNN and SSAE-f. These results demonstrated that CNN significantly improved performance and increased robustness over time compared with standard LDA with associated handcrafted features. This data-driven features extraction approach may overcome the problem of the feature calibration and selection in myoelectric control.

WARMING ISSUES ASSOCIATED WITH THE LONG TERM SIMULATION OF HOUSING USING CFD ANALYSIS

2016 ◽  
Vol 11 (2) ◽  
pp. 57-74 ◽  
Author(s):  
Aiman Albatayneh ◽  
Dariusz Alterman ◽  
Adrian W. Page ◽  
Behdad Moghtaderi
Keyword(s):  
Air Temperature ◽  
Cfd Simulation ◽  
Heating And Cooling ◽  
And Performance ◽  
External Volume ◽  
Cooling Loads ◽  
Long Term Performance ◽  
Term Performance

The determination of internal building air temperature has an impact on the design and performance of a building in measuring thermal comfort and heating and cooling loads. There is software to assist with measuring internal building air temperature such as Autodesk CFD simulation. However, the use of Autodesk CFD simulation for the analysis appears to have an issue with simulations extending over a long term (i.e. months or years) as the internal air temperature in a building keeps rising with time. This paper addresses the challenges encountered using CFD simulation in the modelling of a building for long term performance. A new method to overcome the issue of the progressive rising of internal air temperature using two external air boundaries, one for the external volume (sky boundary) and the other surrounding the building, is suggested in the paper.

Technological Innovation Inputs, Outputs, and Performance

2016 ◽  
Vol 29 (3) ◽  
pp. 327-346 ◽  
Author(s):  
Julio Diéguez-Soto ◽  
Montserrat Manzaneque ◽  
Alfonso A. Rojo-Ramírez
Keyword(s):  
Research And Development ◽  
Technological Innovation ◽  
Family Management ◽  
And Performance ◽  
Long Term Performance ◽  
Term Performance ◽  
Moderating Role ◽  
Innovation Outcomes

The aim of this research is to study the moderating role of family management in the relationships between the intensity of research and development and the occurrence of continuous technological innovation and between the existence of technological innovation outcomes and long-term firm performance. The results show that family management reduces efficiency in the conversion of research and development expenses into technological innovation outcomes over time. Our findings also suggest that the influence of family management significantly contributes to improving the effect of the achievement of technological innovation on long-term performance.

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