scholarly journals Creating underwater vision through wavy whiskers: a review of the flow-sensing mechanisms and biomimetic potential of seal whiskers

2021 ◽  
Vol 18 (183) ◽  
Author(s):  
Xingwen Zheng ◽  
Amar M. Kamat ◽  
Ming Cao ◽  
Ajay Giri Prakash Kottapalli
Keyword(s):  
Signal To Noise Ratio ◽  
Future Research ◽  
Structural Morphology ◽  
Left Behind ◽  
Flow Sensing ◽  
Swimming Motion ◽  
Underwater Vision ◽  
Vortex Induced Vibrations ◽  
Behavioural Experiments ◽  
Viv Suppression

Seals are known to use their highly sensitive whiskers to precisely follow the hydrodynamic trail left behind by prey. Studies estimate that a seal can track a herring that is swimming as far as 180 m away, indicating an incredible detection apparatus on a par with the echolocation system of dolphins and porpoises. This remarkable sensing capability is enabled by the unique undulating structural morphology of the whisker that suppresses vortex-induced vibrations (VIVs) and thus increases the signal-to-noise ratio of the flow-sensing whiskers. In other words, the whiskers vibrate minimally owing to the seal's swimming motion, eliminating most of the self-induced noise and making them ultrasensitive to the vortices in the wake of escaping prey. Because of this impressive ability, the seal whisker has attracted much attention in the scientific community, encompassing multiple fields of sensory biology, fluid mechanics, biomimetic flow sensing and soft robotics. This article presents a comprehensive review of the seal whisker literature, covering the behavioural experiments on real seals, VIV suppression capabilities enabled by the undulating geometry, wake vortex-sensing mechanisms, morphology and material properties and finally engineering applications inspired by the shape and functionality of seal whiskers. Promising directions for future research are proposed.

Elementary Teachers’ Knowledge and Use of Interventions and Barriers to Promoting Student Self-Determination

2010 ◽  
Vol 45 (3) ◽  
pp. 149-156 ◽  
Author(s):  
Hyun-Jeong Cho ◽  
Michael Wehmeyer ◽  
Neal Kingston
Keyword(s):  
Academic Achievement ◽  
No Child Left Behind ◽  
Elementary Teachers ◽  
Special Educators ◽  
Self Determination ◽  
Future Research ◽  
Student Academic Achievement ◽  
Left Behind ◽  
Education Improvement ◽  
Perceived Importance

The No Child Left Behind Act (2001) and the Individuals with Disabilities Education Improvement Act (2004) emphasize accountability to improve student academic achievement. Promoting self-determination has been proposed as a means to achieving this outcome. Elementary teachers in 30 states were surveyed to measure (a) their perceived importance of self-determination, (b) to what extent they teach it, and (c) the barriers that inhibit them from teaching it. Both general and special educators assigned considerable importance to self-determination instruction and reported at least occasionally providing such instruction. The authors found a lack of congruence between the value teachers place on promoting self-determination and the time they devote to teaching it. Limitations and implications are discussed, and suggestions for future research are offered.

Throughput Dependence on SNR in IEEE802.11 WLAN Systems

2019 ◽  
pp. 1307-1323
Author(s):  
Ikponmwosa Oghogho
Keyword(s):  
High Throughput ◽  
Signal To Noise Ratio ◽  
Physical Layer ◽  
Future Research ◽  
Cross Layer ◽  
Signal To Noise ◽  
Research Directions ◽  
Data Rates ◽  
Research Findings ◽  
Future Research Directions

This chapter seeks to present the dependence of throughput on signal to noise ratio (SNR) in IEEE802.11 WLAN systems. High throughput and low delays are presented as the requirements for indicating good performance of WLAN systems. The multiple communication data rates specified by the physical layer of IEEE802.11 WLANs which vary depending on the SNR observed is shown to appreciably influence the throughput experienced by the users. Cross-layer modelling principles which simplifies the process of estimating the dependence of throughput on SNR is presented. Recent research findings which apply cross-layer modelling principles to model the dependence of throughput on SNR only is presented along with future research directions.

A Scoping Review of Interventions to Promote Health and Well-Being of Left-behind Children in Mainland China

2019 ◽  
Vol 50 (5) ◽  
pp. 1419-1439 ◽  
Author(s):  
Miao Wang ◽  
Bryan G Victor ◽  
Jun Sung Hong ◽  
Shiyou Wu ◽  
Jin Huang ◽  
...  
Keyword(s):  
Rural Areas ◽  
Mainland China ◽  
Well Being ◽  
Future Research ◽  
Collaborative Relationships ◽  
Left Behind ◽  
Nursing Services ◽  
Study Team ◽  
Comprehensive Search ◽  
Chinese And English

Abstract Approximately 65 million children in mainland China are left behind in rural areas while their parents work in the cities. Research has highlighted their health needs. However, current research on interventions for this population is unknown. The purpose of this study was to systematically review existing health service interventions for left-behind children in China. The study team identified interventions for left-behind children by conducting a comprehensive search of major academic databases for Chinese and English research. Articles were retained in the study if they were original empirical intervention studies that target health and related well-being outcomes of left-behind children. A total of eighteen unique studies met inclusion criteria. The majority of them demonstrated positive outcomes using various modalities, including education, sport and nutrition guidance and nursing services. However, the shortcomings in research design and intervention limit their replication. Intervention research for left-behind children shows an enormous gap in the knowledge about this at-risk group. Of the existing programs identified, we observe considerable promise for interventions based on inter-disciplinary approaches to services. We provide additional recommendations for conducting future research and for building collaborative relationships with social workers to better serve the needs of children.

scholarly journals Local flow sensing on helical microrobots for semi-automatic motion adaptation

2019 ◽  
Vol 39 (4) ◽  
pp. 476-489 ◽  
Author(s):  
Antoine Barbot ◽  
Dominique Decanini ◽  
Gilgueng Hwang
Keyword(s):  
Closed Loop ◽  
Flow Speed ◽  
Closed Loop Control ◽  
Flow Profile ◽  
Microfluidic Chips ◽  
Level Control ◽  
Local Flow ◽  
Loop Control ◽  
Flow Sensing ◽  
Swimming Motion

Helical microrobots with dimensions below 100 µm could serve many applications for manipulation and sensing in small, closed environments such as blood vessels or inside microfluidic chips. However, environmental conditions such as surface stiction from the channel wall or local flow can quickly result in the loss of control of the microrobot, especially for untrained users. Therefore, to automatically adapt to changing conditions, we propose an algorithm that switches between a surface-based motion of the microrobot and a 3D swimming motion depending on the local flow value. Indeed swimming is better for avoiding obstacles and difficult surface stiction areas but it is more sensitive to the flow than surface motion such as rolling or spintop motion. First, we prove the flow sensing ability of helical microrobots based on the difference between the tracked and theoretical speed. For this, a 50 µm long and 5 µm diameter helical microrobot measures the flow profile shape in two different microchannels. These measurements are then compared with simulation results. Then, we demonstrate both swimming and surface-based motion using closed-loop control. Finally, we test our algorithm by following a 2D path using closed-loop control, and adapting the type of motion depending on the flow speed measured by the microrobot. Such results could enable simple high-level control that could expand the development of microrobots toward applications in complex microfluidic environments.

Full Scale Fairing Qualification Tests

2015 ◽  
Author(s):  
Yiannis Constantinides ◽  
Stergios Liapis ◽  
Don Spencer ◽  
Mohammed Islam ◽  
Kjetil Skaugset ◽  
...  
Keyword(s):  
Fatigue Failure ◽  
Model Test ◽  
Hydrodynamic Performance ◽  
Documented Case ◽  
Vortex Induced Vibrations ◽  
Viv Suppression ◽  
Single Pipe ◽  
Interference Tests ◽  
Fin Design ◽  
Novel Design

Production risers as well as drilling risers are often subjected to Vortex-induced vibrations (VIV) when exposed to ocean currents. VIV have been observed in the field and can cause fatigue failure and excessive drag on the riser. In order to suppress VIV and reduce drag, fairings are often used. This paper presents hydrodynamic qualification tests for two types of fairings: the short crab claw (SCC) and a tapered dual fin design. The short crab claw fairing design is a novel design that was developed by the Norwegian Deepwater Programme (NDP). As will be detailed in this paper, the SCC design offers very low drag, completely suppresses VIV and reduces riser interference. In 2012, a model test campaign was undertaken to understand and qualify the hydrodynamic performance of fairings at prototype conditions. The program consisted of testing the three fairing geometries and a strake to understand the stand-alone performance in VIV and the performance in interference. This was accomplished by utilizing a single pipe setup for the standalone test and a two-pipe setup for the interference tests. The paper reports the results of the program and draws conclusions on the hydrodynamic performance of the VIV suppression devices tested. Overall, all VIV suppression devices tested were able to suppress VIV with the SCC fairing being the most effective. In all cases tested, the downstream fairings / strakes were very effective in suppressing VIV in an interference scenario where a fairing was placed upstream. Contrary to the well-documented case of two strakes in tandem, in this case the upstream fairings did not reduce the effectiveness of the downstream fairings/strakes.

The Human Controller as an Adaptive, Low Pass Filter

1967 ◽  
Vol 9 (2) ◽  
pp. 141-147 ◽  
Author(s):  
Gordon H. Robinson
Keyword(s):  
Signal To Noise Ratio ◽  
Noise Signal ◽  
Manual Control ◽  
Future Research ◽  
Research Needs ◽  
Descriptive Model ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Independent Variables ◽  
Low Pass

Data is presented on the ability of a human controller to track a signal contaminated with noise. Signal frequencies and signal-to-noise ratio are the independent variables. An optimal, adaptive filter is presented for comparison. A descriptive model is derived based on known human characteristics in manual control. Future research needs are discussed.

scholarly journals Intraoperative identification of somato-sensory brain areas using optical imaging and standard RGB camera equipment – a feasibility study

2015 ◽  
Vol 1 (1) ◽  
pp. 265-269
Author(s):  
M. Oelschlägel ◽  
T. Meyer ◽  
S. B. Sobottka ◽  
M. Kirsch ◽  
G. Schackert ◽  
...  
Keyword(s):  
Optical Properties ◽  
Optical Imaging ◽  
Signal To Noise Ratio ◽  
Image Data ◽  
Ccd Camera ◽  
Future Research ◽  
Imaging Method ◽  
Color Channel ◽  
Surgical Workflow ◽  
Recent Developments

AbstractIntraoperative Optical Imaging (IOI) is a neuro-imaging technique that allows the visualization of changes in optical properties of the brain cortex. Recent developments enhanced the method regarding the robustness under intraoperative conditions. However, the necessity of additional hardware still limits the use in the operating room (OR). Since modern surgical microscopes are potentially equipped with all required hardware for imaging, we investigated the possible use of such standard RGB camera for IOI. Measurements were performed on eight patients. Changes in optical properties of the cortical surface were acquired with a monochrome CCD camera (AxioCam MRm) and simultaneously with a standard RGB camera (Trio 610). Maps of cortical activity were calculated from the image data and the quality of these maps was assessed with a spatial signal-to-noise ratio. Activity maps calculated from AxioCam MRm data showed highest SNR in six out of eight patients. In two patients the activity map calculated from Trio 610 red channel performed best overall. The Trio 610 maps calculated from red channel data performed best in three out of eight cases like the activity maps calculated from green channel data, whereas the activity map calculated from blue channel data performed best in only two cases. If the color channel with the highest SNR is chosen in each patient for comparison to AxioCam MRm, the median of the SNR (SNRAxioCam/SNRBestColorChannel) is 84 % (Quartile 1 (Q1): 78 %, Quartile 3 (Q3): 99%). Results reveal that the integration of the Intraoperative Optical Imaging method into the OR and surgical workflow can be further improved by using RGB camera equipment. A robust identification of somato-sensory areas seems possible. Due to the gain of information from different wavelength bands the need for intelligent evaluation algorithms is increased and should therefore be topic of future research.

Fairing Evaluation Based on Numerical Simulation

2012 ◽  
Author(s):  
Juan P. Pontaza ◽  
Mohan Kotikanyadanam ◽  
Piet Moeleker ◽  
Raghu G. Menon ◽  
Shankar Bhat
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Current Speed ◽  
Full Scale ◽  
Attractive Alternative ◽  
Element Analysis ◽  
Vortex Induced Vibrations ◽  
Helical Strakes ◽  
Computational Fluid Dynamics Cfd ◽  
Viv Suppression

It is well established that strakes are effective at suppressing vortex-induced vibrations (VIV). Fairings are an attractive alternative to helical strakes, because they are a low drag VIV suppression solution. The paper presents an evaluation of a fairing design, based on numerical simulations — to be complemented at a later stage with current tank testing. This paper documents the computational fluid dynamics (CFD) and finite element analysis (FEA) of the evaluation: (1) 3-D CFD in the laboratory scale: 4.5 inch pipe, 3 ft/s current speed, (2) 3-D CFD in the full scale: 14 inch riser, 4 knots current speed, and (3) 3-D FEA of the full-scale fairing module latching mechanism, under service loads corresponding to 4 knots current speed. The analysis results show that the fairing design (1) is effective at suppressing VIV, (2) yields a low drag coefficient (0.52 at Re ∼ 106), and (3) its latching mechanism is adequate for use in calm sea states with 4 knots current speeds.

scholarly journals Human Resource Management Practices and Its Effects on Job Satisfaction Levels of Employees

2019 ◽  
Vol 8 (2) ◽  
pp. 102-112
Author(s):  
Khurram Sultan ◽  
Goran Ismael ◽  
Omar Mohammad ◽  
Safin Abas ◽  
Muhammad Abdulla
Keyword(s):  
Job Satisfaction ◽  
Management Practices ◽  
Future Research ◽  
Iron And Steel ◽  
Left Behind ◽  
Hr Practices ◽  
Human Resource Management Practices ◽  
Steel Sector ◽  
Degree Of Association ◽  
The Impact

This study aims to investigate the impact of HRM practices and its effect on employee’s job satisfaction in the iron and steel sector of Erbil, KRI. The objectives of the study are three fold, first to measure the degree of association between HR practices and job satisfaction. Second, to find out the impact of HR practices on job satisfaction and at last to propose some measures in order to enhance the job satisfaction level of the employees concerned to the selected iron & steel enterprises. A structured questionnaire was developed and distributed among 70 employees of three firms in Erbil, whereas 50 employees answered rightly. Most of the employees showed positive answers toward HR practices on them. This thing leads toward rejection of our Ho and acceptance of  H1. Those who left behind with less positive answers  main reason were found during survey that was they are with less education so that’s why they get less opportunities in order to develop themselves. Related to future research other authors can consider other variables that are not coved by this research such as staffing and package because human practices coves various range.  

On Ambient Information Systems

2010 ◽  
pp. 145-155
Author(s):  
William R. Hazlewood ◽  
Lorcan Coyle
Keyword(s):  
Information Systems ◽  
Web 2.0 ◽  
Physical Environment ◽  
Information Overload ◽  
Signal To Noise Ratio ◽  
Physical World ◽  
Research Community ◽  
Future Research ◽  
The Internet ◽  
Signal To Noise

The rise of the Internet, the ever increasing ubiquity of data, and its low signal-to-noise ratio have contributed to the problem of information overload, whereby individuals have access to more data than they can assimilate into meaningful and actionable information. Much of the success of Web 2.0 has been achieved after an effective tackling of this problem. Ambient Information Systems take the battle into the physical world by integrating information into the physical environment in a non-intimidating and non-overloading fashion. After two international workshops on Ambient Information Systems, we outline our vision for the field, consolidate a new definition, identify the key concerns of the research community, and issue a call to arms for future research.

Sign in / Sign up

Export Citation Format

Share Document