Optimal Stiffness Design for an Exhaustive Parallel Compliance Matrix in Multiactuator Robotic Limbs

Comparatively slow growth in energy density of both power storage and generation technologies has placed added emphasis on the need for energy-efficient designs in legged robots. This paper explores the potential of parallel springs in robot limb design. We start by adding what we call the exhaustive parallel compliance matrix (EPCM) to the design. The EPCM is a set of parallel springs, which includes a parallel spring for each joint and a multijoint parallel spring for all possible combinations of the robot's joints. Then, we carefully formulate and compare two performance metrics, which improve various aspects of the system performance. Each performance metric is analyzed and compared, their strengths and weaknesses being rigorously presented. The performance benefits associated with this approach are dramatic. Implementing the spring matrix reduces the sum of square power (SSP) exerted by the actuators by up to 47%, the peak power requirement by almost 40%, the sum of squared current by 55%, and the peak current by 55%. These results were generated using a planar robot limb and a gait trajectory borrowed from biology. We use a fully dynamic model of the robotic system including inertial effects. We also test the design robustness using a perturbation study, which shows that the parallel springs are effective even in the presence of trajectory perturbation.

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Opportunistic Large Array Propagation Models: A Comprehensive Survey

Sensors ◽

10.3390/s21124206 ◽

2021 ◽

Vol 21 (12) ◽

pp. 4206

Author(s):

Farhan Nawaz ◽

Hemant Kumar ◽

Syed Ali Hassan ◽

Haejoon Jung

Keyword(s):

Energy Efficient ◽

Large Scale ◽

Performance Metrics ◽

Experimental Studies ◽

Cooperative Transmission ◽

Analytical Models ◽

Future Research ◽

Large Array ◽

Propagation Models ◽

Comprehensive Survey

Enabled by the fifth-generation (5G) and beyond 5G communications, large-scale deployments of Internet-of-Things (IoT) networks are expected in various application fields to handle massive machine-type communication (mMTC) services. Device-to-device (D2D) communications can be an effective solution in massive IoT networks to overcome the inherent hardware limitations of small devices. In such D2D scenarios, given that a receiver can benefit from the signal-to-noise-ratio (SNR) advantage through diversity and array gains, cooperative transmission (CT) can be employed, so that multiple IoT nodes can create a virtual antenna array. In particular, Opportunistic Large Array (OLA), which is one type of CT technique, is known to provide fast, energy-efficient, and reliable broadcasting and unicasting without prior coordination, which can be exploited in future mMTC applications. However, OLA-based protocol design and operation are subject to network models to characterize the propagation behavior and evaluate the performance. Further, it has been shown through some experimental studies that the most widely-used model in prior studies on OLA is not accurate for networks with networks with low node density. Therefore, stochastic models using quasi-stationary Markov chain are introduced, which are more complex but more exact to estimate the key performance metrics of the OLA transmissions in practice. Considering the fact that such propagation models should be selected carefully depending on system parameters such as network topology and channel environments, we provide a comprehensive survey on the analytical models and framework of the OLA propagation in the literature, which is not available in the existing survey papers on OLA protocols. In addition, we introduce energy-efficient OLA techniques, which are of paramount importance in energy-limited IoT networks. Furthermore, we discuss future research directions to combine OLA with emerging technologies.

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An experimental study on feature-based SLAM for multi-legged robots with RGB-D sensors

Industrial Robot the international journal of robotics research and application ◽

10.1108/ir-11-2016-0340 ◽

2017 ◽

Vol 44 (4) ◽

pp. 428-441 ◽

Cited By ~ 11

Author(s):

Michał R. Nowicki ◽

Dominik Belter ◽

Aleksander Kostusiak ◽

Petr Cížek ◽

Jan Faigl ◽

...

Keyword(s):

Performance Metrics ◽

State Of The Art ◽

Building Blocks ◽

Bundle Adjustment ◽

The State ◽

Legged Robots ◽

Evaluation Methodology ◽

Walking Robots ◽

Content Type ◽

Feature Based

Purpose This paper aims to evaluate four different simultaneous localization and mapping (SLAM) systems in the context of localization of multi-legged walking robots equipped with compact RGB-D sensors. This paper identifies problems related to in-motion data acquisition in a legged robot and evaluates the particular building blocks and concepts applied in contemporary SLAM systems against these problems. The SLAM systems are evaluated on two independent experimental set-ups, applying a well-established methodology and performance metrics. Design/methodology/approach Four feature-based SLAM architectures are evaluated with respect to their suitability for localization of multi-legged walking robots. The evaluation methodology is based on the computation of the absolute trajectory error (ATE) and relative pose error (RPE), which are performance metrics well-established in the robotics community. Four sequences of RGB-D frames acquired in two independent experiments using two different six-legged walking robots are used in the evaluation process. Findings The experiments revealed that the predominant problem characteristics of the legged robots as platforms for SLAM are the abrupt and unpredictable sensor motions, as well as oscillations and vibrations, which corrupt the images captured in-motion. The tested adaptive gait allowed the evaluated SLAM systems to reconstruct proper trajectories. The bundle adjustment-based SLAM systems produced best results, thanks to the use of a map, which enables to establish a large number of constraints for the estimated trajectory. Research limitations/implications The evaluation was performed using indoor mockups of terrain. Experiments in more natural and challenging environments are envisioned as part of future research. Practical implications The lack of accurate self-localization methods is considered as one of the most important limitations of walking robots. Thus, the evaluation of the state-of-the-art SLAM methods on legged platforms may be useful for all researchers working on walking robots’ autonomy and their use in various applications, such as search, security, agriculture and mining. Originality/value The main contribution lies in the integration of the state-of-the-art SLAM methods on walking robots and their thorough experimental evaluation using a well-established methodology. Moreover, a SLAM system designed especially for RGB-D sensors and real-world applications is presented in details.

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Abstract ACO-EEAODR: An Ant-Swarm Inspired Energy-Efficient Ad Hoc On-Demand Routing Protocol for Mobile Ad Hoc Networks

10.32920/ryerson.14654271.v1 ◽

2021 ◽

Author(s):

Waqas Shah

Keyword(s):

Network Lifetime ◽

Routing Protocol ◽

Energy Efficient ◽

Ad Hoc ◽

Performance Metrics ◽

Minimum Energy ◽

Sustainable Growth ◽

Energy Aware ◽

On Demand ◽

Demand Routing

As the world’s economic activities are expanding, the energy comes to the fore to the question of the sustainable growth in all technological areas, including wireless mobile networking. Energyaware routing schemes for wireless networks have spurred a great deal of recent research towards achieving this goal. Recently, an energy-aware routing protocol for MANETs (so-called energy-efficient ad hoc on-demand routing protocol (EEAODR) for MANETs was proposed, in which the energy load among nodes is balanced so that a minimum energy level is maintained and the resulting network lifetime is increased. In this paper, an Ant Colony Optimization (ACO) inspired approach to EEAODR (ACO-EEAODR) is proposed. To the best of our knowledge, no attempts have been made so far in this direction. Simulation results are provided, demonstrating that the ACO-EEAODR outperforms the EEAODR scheme in terms of energy consumed and network lifetime, chosen as performance metrics.

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Considerations for performance metrics of metagenomic next generation sequencing analyses

10.1101/2020.12.17.423212 ◽

2020 ◽

Author(s):

Jason G. Kralj ◽

Stephanie L. Servetas ◽

Samuel P. Forry ◽

Scott A. Jackson

Keyword(s):

Performance Metrics ◽

Limit Of Detection ◽

Clinical Performance ◽

Ground Truth ◽

Negative Control ◽

Fitness For Purpose ◽

Performance Metric ◽

The One ◽

Sensitivity Specificity ◽

Harmonic Means

AbstractEvaluating the performance of metagenomics analyses has proven a challenge, due in part to limited ground-truth standards, broad application space, and numerous evaluation methods and metrics. Application of traditional clinical performance metrics (i.e. sensitivity, specificity, etc.) using taxonomic classifiers do not fit the “one-bug-one-test” paradigm. Ultimately, users need methods that evaluate fitness-for-purpose and identify their analyses’ strengths and weaknesses. Within a defined cohort, reporting performance metrics by taxon, rather than by sample, will clarify this evaluation. An estimated limit of detection, positive and negative control samples, and true positive and negative true results are necessary criteria for all investigated taxa. Use of summary metrics should be restricted to comparing results of similar cohorts and data, and should employ harmonic means and continuous products for each performance metric rather than arithmetic mean. Such consideration will ensure meaningful comparisons and evaluation of fitness-for-purpose.

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Modeling the performance of healthcare construction projects

Engineering Construction & Architectural Management ◽

10.1108/ecam-08-2018-0323 ◽

2019 ◽

Vol 26 (9) ◽

pp. 2023-2039

Author(s):

Karim A. Iskandar ◽

Awad S. Hanna ◽

Wafik Lotfallah

Keyword(s):

Mathematical Model ◽

Performance Metrics ◽

Project Performance ◽

The Body ◽

Assessment Tools ◽

Healthcare Sector ◽

High Tech ◽

Relative Importance ◽

Content Type ◽

Performance Metric

Purpose Healthcare-sector projects are some of the most complex in modern practice due to their reliance on high-tech components and the level of precision they must maintain. Existing literature in healthcare performance specifically is scarce, but there is a recent increasing trend in both healthcare construction and a corresponding trend in related literature. No previously existing study has derived weights (relative importance) of performance metric in an objective, data-based manner. The purpose of this paper is to present a newly developed mathematical model that derives these weights, free of subjectivity that is common in other literature. Design/methodology/approach This paper’s model considers 17 exceptional projects and 19 average projects, and reveals the weights (or relative importance) of ten performance metrics by comparing how projects relate to one another in terms of each metric individually. It solves an eigenvalue problem that maximizes the difference between average and exceptional project performances. Findings The most significant weight, i.e. the performance metric which has the greatest impact on healthcare project performance, was request for information per million dollars with a weight of 16.07 percent. Other highly weighted metrics included construction speed and schedule growth at 13.08 and 12.23 percent, respectively. Rework was the least significant metric at 3.61 percent, but not all metrics of quality had low ratings. Deficiency issues per million dollars was weighted at 11.61 percent, for example. All weights derived by the model in this paper were validated statistically to ensure their applicability as comparison and assessment tools. Originality/value There is no widely accepted measure of project performance specific to healthcare construction. This study’s contribution to the body of knowledge is its mathematical model which is a landmark effort to develop a single, objective, unified project performance index for healthcare construction. Furthermore, this unified score presents a user-friendly avenue for contractors to standardize their productivity tracking – a missing piece in the practices of many contractors.

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Performance Metrics for Product Flow Configuration in a Reconfigurable Manufacturing System (RMS)

Volume 1: Additive Manufacturing; Manufacturing Equipment and Systems; Bio and Sustainable Manufacturing ◽

10.1115/msec2019-2951 ◽

2019 ◽

Cited By ~ 1

Author(s):

Prince Pal Singh ◽

Jatinder Madan ◽

Harwinder Singh

Keyword(s):

Manufacturing System ◽

Performance Metrics ◽

Reconfigurable Manufacturing ◽

Reconfigurable Manufacturing System ◽

Industrial Case Study ◽

Flow Configuration ◽

Product Flow ◽

Performance Metric ◽

Hierarchy Process

Abstract We propose a systematic approach for product flow configuration selection for reconfigurable manufacturing system (RMS) that considers ten industrially relevant most important factors. The paper first defines performance metrics for the identified factors. A composite performance metric (CPM) has been proposed, which accounts for all ten-performance metrics to assess the performance of RMS with the help of a combined score. The methodology of developing CPM applies analytical hierarchy process (AHP) approach where weightage to each of the performance metric is also considered. To showcase the usefulness and feasibility of the CPM, it has been applied in an industrial environment with the help of an industrial case study. Both the CPM and other metric scores were found to be quite useful to identify a suitable configuration out of the available alternatives.

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Validation of phlebotomy performance metrics developed as part of a proficiency-based progression initiative to mitigate wrong blood in tube

Postgraduate Medical Journal ◽

10.1136/postgradmedj-2019-137254 ◽

2020 ◽

pp. postgradmedj-2019-137254

Author(s):

Noirin O’Herlihy ◽

Sarah Griffin ◽

Patrick Henn ◽

Robert Gaffney ◽

Mary Rose Cahill ◽

...

Keyword(s):

Construct Validity ◽

Performance Metrics ◽

Working Environment ◽

Modified Delphi ◽

Video Recordings ◽

Performance Metric ◽

Large Teaching Hospital ◽

Wide Range ◽

The Mean ◽

A Performance

AimsThe purpose of this study was to (1) characterise the procedure of phlebotomy, deconstruct it into its constituent parts and develop a performance metric for the purpose of training healthcare professionals in a large teaching hospital and to (2) evaluate the construct validity of the phlebotomy metric and establish a proficiency benchmark.MethodBy engaging with a multidisciplinary team with a wide range of experience of preanalytical errors in phlebotomy and observing video recordings of the procedure performed in the actual working environment, we defined a performance metric. This was brought to a modified Delphi meeting, where consensus was reached by an expert panel. To demonstrate construct validity, we used the metric to objectively assess the performance of novices and expert practitioners.ResultsA phlebotomy metric consisting of 11 phases and 77 steps was developed. The mean inter-rater reliability was 0.91 (min 0.83, max 0.95). The expert group completed more steps of the procedure (72 vs 69), made fewer errors (19 vs 13, p=0.014) and fewer critical errors (1 Vs 4, p=0.002) than the novice group.ConclusionsThe metrics demonstrated construct validity and the proficiency benchmark was established with a minimum observation of 69 steps, with no critical errors and no more than 13 errors in total.

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