The Experts below are selected from a list of 216 Experts worldwide ranked by ideXlab platform
Christopher G Lowe - One of the best experts on this subject based on the ideXlab platform.
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IROS - Acoustic Tag State Estimation with Unsynchronized Hydrophones on AUVs
2018 IEEE RSJ International Conference on Intelligent Robots and Systems (IROS), 2018Co-Authors: Tianyi Ma, Christopher M Clark, Eyassu Shimelis, Charles Van Eijk, Christopher G LoweAbstract:This paper presents an underwater robotic sensor system for localizing Acoustic transmitters when the robot's hydrophones cannot be time-synchronized. The development of the system is motivated by applications where tracking of marine animals that are Tagged with an underwater Acoustic transmitter is required. The system uses two novel real-time calibration algorithms that improve the accuracy of time of flight (TOF) and time difference of arrival (TDOA) measurements. The first algorithm corrects non-linear clock skews in TOF measurements based on temperature variation. The second algorithm compensates the localized relative clock skew between clocks using a mixed integer linear program. To validate the system's performance, an Autonomous Underwater Vehicle (AUV) was deployed to track a moving Tag where GPS data was used as ground truth. Compared to traditional TOF and TDOA filtering methods, the results show that the proposed system can achieve reduction of mean localization errors by 59%, and a reduction of the standard deviation of measurements by 44%.
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Acoustic Tag State Estimation with Unsynchronized Hydrophones on AUVs
2018 IEEE RSJ International Conference on Intelligent Robots and Systems (IROS), 2018Co-Authors: Eyassu Shimelis, Christopher M Clark, Charles Van Eijk, Christopher G LoweAbstract:This paper presents an underwater robotic sensor system for localizing Acoustic transmitters when the robot's hydrophones cannot be time-synchronized. The development of the system is motivated by applications where tracking of marine animals that are Tagged with an underwater Acoustic transmitter is required. The system uses two novel real-time calibration algorithms that improve the accuracy of time of flight (TOF) and time difference of arrival (TDOA) measurements. The first algorithm corrects non-linear clock skews in TOF measurements based on temperature variation. The second algorithm compensates the localized relative clock skew between clocks using a mixed integer linear program. To validate the system's performance, an Autonomous Underwater Vehicle (AUV) was deployed to track a moving Tag where GPS data was used as ground truth. Compared to traditional TOF and TDOA filtering methods, the results show that the proposed system can achieve reduction of mean localization errors by 59%, and a reduction of the standard deviation of measurements by 44%.
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a multi autonomous underwater vehicle system for autonomous tracking of marine life
Journal of Field Robotics, 2017Co-Authors: Yukun Lin, Jerry Hsiung, Richard Piersall, Connor F. White, Christopher G Lowe, Christopher M ClarkAbstract:This paper presents a multi-autonomous underwater vehicle system capable of cooperatively and autonomously tracking and following marine targets (i.e., fish) Tagged with an Acoustic transmitter. The AUVs have been equipped with stereo-hydrophones that receive signals broadcasted by the Acoustic transmitter Tags to enable real-time calculation of bearing-to-Tag and distance-to-Tag measurements. These measurements are shared between AUVs via Acoustic modem and fused within each AUV's particle filter for estimating the target's position. The AUVs use a leader/follower multi-AUV control system to enable the AUVs to drive toward the estimated target state by following collision-free paths. Once within the local area of the target, the AUVs circumnavigate the target state until it moves to another area. The system builds on previous work by incorporating a new SmartTag package that can be attached to an individual's dorsal fin. The SmartTag houses a full inertial measurement unit (INU), video logger, Acoustic transmitter, and timed release mechanism. After real-time AUV tracking experiments, the SmartTag is recovered. Logged IMU data are fused with logged AUV-obtained Acoustic Tag measurements within a particle filter to improve state estimation accuracy. This improvement is validated through a series of multi-AUV shark and boat tracking experiments conducted at Santa Catalina Island, California. When compared with previous work that did not use the SmartTag package, results demonstrated a decrease in mean position estimation error of 25–75%, Tag orientation estimation errors dropped from 80° to 30° , the sensitivity of mean position error with respect to distance to the Tag was less by a factor of 50, and the sensitivity of mean position error with respect to Acoustic signal reception frequency to the Tag was 25 times less. These statistics demonstrate a large improvement in the system's robustness when the SmartTag package is used.
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Human vs robot: Comparing the viability and utility of autonomous underwater vehicles for the Acoustic telemetry tracking of marine organisms
Journal of Experimental Marine Biology and Ecology, 2016Co-Authors: Connor F. White, Christopher M Clark, Christopher G LoweAbstract:Currently, individual animal movement data can be obtained using a variety of methods, but each methodology is limited in either temporal or spatial resolution. A new method of active tracking was developed which utilizes autonomous underwater vehicles (AUV) equipped with stereo-hydrophones that can accurately estimate the position of a moving Acoustic Tag, while remaining at a distance. This technology was tested and compared to standard human-based active tracking technology to understand the benefits and limitations of this new technique. An AUV and a researcher independently tracked stationary and moving targets of known location in order to compare their spatial and temporal accuracy. Both methods were then used to track a leopard shark, Triakis semifasciata, in the field. The autonomous vehicle accurately positioned both stationary and moving Tags with a positional error of < 10 m. For stationary transmitters, the AUV and the researcher were comparable, but when tracking moving transmitters, the AUV had significantly better spatial accuracy. Throughout all trials, the AUV had a higher frequency of accurate location estimates than a researcher actively tracking. Based on these findings, the AUV was able to more accurately track and record the position of an Acoustically Tagged shark in the field. Using this new technology, researchers should be able to maintain or improve the spatial resolution of measurements when actively tracking Acoustically Tagged individuals and will be able to increase the temporal resolution of measurements while minimizing the potential influence of tracking on the behavior of the animal.
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A multi-AUV system for cooperative tracking and following of leopard sharks
2013 IEEE International Conference on Robotics and Automation, 2013Co-Authors: Dylan Shinzaki, Chris Gage, Mark Moline, Barrett Wolfe, Sarah Tang, Christopher G Lowe, Christopher ClarkAbstract:This paper presents a system of multiple coordinating autonomous underwater vehicles (AUV) that can localize and track a shark Tagged with an Acoustic transmitter. Each AUV is equipped with a stereo-hydrophone system that provides measurements of the relative bearing to the transmitter, as well as an Acoustic modem that allows for inter-AUV communication and hence cooperative shark state estimation and decentralized tracking control. Online state estimation of the shark's state is performed using a Particle Filter in which measurements are shared between AUVs. The decentralized control system enables the AUVs to circumnavigate a dynamic target, (i.e. the estimated shark location). Each AUV circles the target by tracking circles of different radii and at different phase angles with respect to the target so as to obtain simultaneous sensor vanTage points and minimize chance of AUV collision. A series of experiments using two AUVs were conducted in Big Fisherman's Cove in Santa Catalina Island, CA and demonstrated the ability to track a Tagged leopard shark (Triakis semifasciata). The performance of the tracking was compared to standard manual tracking performed using an directional hydrophone operated by a researcher in a boat. In an additional experiment, the AUVs tracked an Acoustic Tag attached to the tracking boat to quantify the error of the state estimation of the system.
Christopher M Clark - One of the best experts on this subject based on the ideXlab platform.
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IROS - Acoustic Tag State Estimation with Unsynchronized Hydrophones on AUVs
2018 IEEE RSJ International Conference on Intelligent Robots and Systems (IROS), 2018Co-Authors: Tianyi Ma, Christopher M Clark, Eyassu Shimelis, Charles Van Eijk, Christopher G LoweAbstract:This paper presents an underwater robotic sensor system for localizing Acoustic transmitters when the robot's hydrophones cannot be time-synchronized. The development of the system is motivated by applications where tracking of marine animals that are Tagged with an underwater Acoustic transmitter is required. The system uses two novel real-time calibration algorithms that improve the accuracy of time of flight (TOF) and time difference of arrival (TDOA) measurements. The first algorithm corrects non-linear clock skews in TOF measurements based on temperature variation. The second algorithm compensates the localized relative clock skew between clocks using a mixed integer linear program. To validate the system's performance, an Autonomous Underwater Vehicle (AUV) was deployed to track a moving Tag where GPS data was used as ground truth. Compared to traditional TOF and TDOA filtering methods, the results show that the proposed system can achieve reduction of mean localization errors by 59%, and a reduction of the standard deviation of measurements by 44%.
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Acoustic Tag State Estimation with Unsynchronized Hydrophones on AUVs
2018 IEEE RSJ International Conference on Intelligent Robots and Systems (IROS), 2018Co-Authors: Eyassu Shimelis, Christopher M Clark, Charles Van Eijk, Christopher G LoweAbstract:This paper presents an underwater robotic sensor system for localizing Acoustic transmitters when the robot's hydrophones cannot be time-synchronized. The development of the system is motivated by applications where tracking of marine animals that are Tagged with an underwater Acoustic transmitter is required. The system uses two novel real-time calibration algorithms that improve the accuracy of time of flight (TOF) and time difference of arrival (TDOA) measurements. The first algorithm corrects non-linear clock skews in TOF measurements based on temperature variation. The second algorithm compensates the localized relative clock skew between clocks using a mixed integer linear program. To validate the system's performance, an Autonomous Underwater Vehicle (AUV) was deployed to track a moving Tag where GPS data was used as ground truth. Compared to traditional TOF and TDOA filtering methods, the results show that the proposed system can achieve reduction of mean localization errors by 59%, and a reduction of the standard deviation of measurements by 44%.
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a multi autonomous underwater vehicle system for autonomous tracking of marine life
Journal of Field Robotics, 2017Co-Authors: Yukun Lin, Jerry Hsiung, Richard Piersall, Connor F. White, Christopher G Lowe, Christopher M ClarkAbstract:This paper presents a multi-autonomous underwater vehicle system capable of cooperatively and autonomously tracking and following marine targets (i.e., fish) Tagged with an Acoustic transmitter. The AUVs have been equipped with stereo-hydrophones that receive signals broadcasted by the Acoustic transmitter Tags to enable real-time calculation of bearing-to-Tag and distance-to-Tag measurements. These measurements are shared between AUVs via Acoustic modem and fused within each AUV's particle filter for estimating the target's position. The AUVs use a leader/follower multi-AUV control system to enable the AUVs to drive toward the estimated target state by following collision-free paths. Once within the local area of the target, the AUVs circumnavigate the target state until it moves to another area. The system builds on previous work by incorporating a new SmartTag package that can be attached to an individual's dorsal fin. The SmartTag houses a full inertial measurement unit (INU), video logger, Acoustic transmitter, and timed release mechanism. After real-time AUV tracking experiments, the SmartTag is recovered. Logged IMU data are fused with logged AUV-obtained Acoustic Tag measurements within a particle filter to improve state estimation accuracy. This improvement is validated through a series of multi-AUV shark and boat tracking experiments conducted at Santa Catalina Island, California. When compared with previous work that did not use the SmartTag package, results demonstrated a decrease in mean position estimation error of 25–75%, Tag orientation estimation errors dropped from 80° to 30° , the sensitivity of mean position error with respect to distance to the Tag was less by a factor of 50, and the sensitivity of mean position error with respect to Acoustic signal reception frequency to the Tag was 25 times less. These statistics demonstrate a large improvement in the system's robustness when the SmartTag package is used.
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Human vs robot: Comparing the viability and utility of autonomous underwater vehicles for the Acoustic telemetry tracking of marine organisms
Journal of Experimental Marine Biology and Ecology, 2016Co-Authors: Connor F. White, Christopher M Clark, Christopher G LoweAbstract:Currently, individual animal movement data can be obtained using a variety of methods, but each methodology is limited in either temporal or spatial resolution. A new method of active tracking was developed which utilizes autonomous underwater vehicles (AUV) equipped with stereo-hydrophones that can accurately estimate the position of a moving Acoustic Tag, while remaining at a distance. This technology was tested and compared to standard human-based active tracking technology to understand the benefits and limitations of this new technique. An AUV and a researcher independently tracked stationary and moving targets of known location in order to compare their spatial and temporal accuracy. Both methods were then used to track a leopard shark, Triakis semifasciata, in the field. The autonomous vehicle accurately positioned both stationary and moving Tags with a positional error of < 10 m. For stationary transmitters, the AUV and the researcher were comparable, but when tracking moving transmitters, the AUV had significantly better spatial accuracy. Throughout all trials, the AUV had a higher frequency of accurate location estimates than a researcher actively tracking. Based on these findings, the AUV was able to more accurately track and record the position of an Acoustically Tagged shark in the field. Using this new technology, researchers should be able to maintain or improve the spatial resolution of measurements when actively tracking Acoustically Tagged individuals and will be able to increase the temporal resolution of measurements while minimizing the potential influence of tracking on the behavior of the animal.
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tracking and following a Tagged leopard shark with an autonomous underwater vehicle
Journal of Field Robotics, 2013Co-Authors: Christopher M Clark, Dylan Shinzaki, Chris Gage, C Forney, E Manii, Michael Farris, Christopher G Lowe, Mark MolineAbstract:This paper presents a prototype system that enables an autonomous underwater vehicle (AUV) to autonomously track and follow a shark that has been Tagged with an Acoustic transmitter. The AUV's onboard processor handles both real-time estimation of the shark's two-dimensional planar position, velocity, and orientation states, as well as a straightforward control scheme to drive the AUV toward the shark. The AUV is equipped with a stereo- hydrophone and receiver system that detects Acoustic signals transmitted by the Acoustic Tag. The particular hydrophone system used here provides a measurement of relative bearing angle to the Tag, but it does not provide the sign (+ or −) of the bearing angle. Estimation is accomplished using a particle filter that fuses bearing measurements over time to produce a state estimate of the Tag location. The particle filter combined with a heuristic-based controller allows the system to overcome the ambiguity in the sign of the bearing angle. The state estimator and control scheme were validated by tracking both a stationary Tag and a moving Tag with known positions. Offline analysis of these data showed that state estimation can be improved by optimizing diffusion parameters in the prediction step of the filter, and considering signal strength of the Acoustic signals in the resampling sTage of the filter. These experiments revealed that state estimate errors were on the order of those obtained by current long-distance shark-tracking methods, i.e., manually driven boat-based tracking systems. Final experiments took place in SeaPlane Lagoon, Los Angeles, where a 1-m leopard shark (Triakis semifasciata) was caught, Tagged, and released before being autonomously tracked and followed by the proposed AUV system for several hours. C
Steven L. Whitlock - One of the best experts on this subject based on the ideXlab platform.
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vitality models found useful in modeling Tag failure times in Acoustic Tag survival studies
Animal Biotelemetry, 2020Co-Authors: John R. Skalski, Steven L. WhitlockAbstract:Acoustic telemetry studies often rely on the assumption that premature Tag failure does not affect the validity of inferences. However, in some cases this assumption is possibly or likely invalid and it is necessary to apply a correction to estimation procedures. The question of which approaches and specific models are best suited to modeling Acoustic Tag failures has received little research attention. In this short communication, we present a meta-analysis of 42 Acoustic Tag-life studies, originally used to correct survival studies involving outmigrating juvenile salmonids in the Columbia/Snake river basin. We compare the performance of nine alternative parametric models including common failure–time/survival models and the vitality models of Li and Anderson Theor Popul Biol 76:118–131, (2009) and Demogr Res 28:341–372, (2013). The Tag-life studies used Acoustic Tags from three different Tag manufacturers, had expected lifetimes between 12 and 61 days, and had dry weights ranging from 0.22 to 1.65 g. In 57% of the cases, the vitality models of Li and Anderson Theor Popul Biol 76:118–131, (2009) and Demogr Res 28:341–372, (2013) fit the Tag-failure times best. The vitality models were also the second-best choices in 17% of the cases. Together, the vitality models, log-logistic, (19%), and gamma models (14%) accounted for 90% of the models selected. Unlike more traditional failure–time models (e.g., Weibull, Gompertz, gamma, and log-logistic), the vitality models are capable of characterizing both the early onset of Tag failure due to manufacturing errors and the anticipated battery life. We provide further guidance on appropriate sample sizes (50–100 Tags) and procedures to be considered when applying precise Tag-life corrections in release–recapture survival studies.
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Vitality Models Found Useful in Modeling Tag-Failure Times in Acoustic-Tag Survival Studies
2020Co-Authors: John R. Skalski, Steven L. WhitlockAbstract:Abstract Acoustic telemetry studies often rely on the assumption that premature Tag failure does not affect the validity of inferences. However, in some cases this assumption is possibly or likely invalid and it is necessary to apply a correction to estimation procedures. The question of which approaches and specific models are best suited to modeling Acoustic Tag failures has received little research attention. In this short communication, we present a meta-analysis of 42 Acoustic Tag-life studies, originally used to correct survival studies involving outmigrating juvenile salmonids in the Columbia/Snake river basin. We compare the performance of nine alternative parametric models including common failure-time/survival models and the vitality models of Li and Anderson (2009 and 2013). The Tag-life studies used Acoustic Tags from three different Tag manufacturers, had expected lifetimes between 12 and 61 days, and had dry weights ranging from 0.22 to 1.65 grams. In 57% of the cases, the vitality models of Li and Anderson (2009 and 2013) fit the Tag failure-times best. The vitality models were also the second-best choices in 17% of the cases. Together, the vitality models, log-logistic, (19%), and gamma models (14%) accounted for 90% of the models selected. Unlike more traditional failure-time models (e.g., Weibull, Gompertz, gamma, and log-logistic), the vitality models are capable of characterizing both the early onset of Tag failure due to manufacturing errors and the anticipated battery life. We provide further guidance on appropriate sample sizes (50–100 Tags) and procedures to be considered when applying precise Tag-life corrections in release-recapture survival studies.
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Vitality Models Found Useful in Modeling Tag-Failure Times in Acoustic-Tag Survival Studies
2020Co-Authors: John R. Skalski, Steven L. WhitlockAbstract:Abstract Acoustic telemetry studies often rely on the assumption that premature Tag failure does not affect the validity of inferences. However, in some cases this assumption is possibly or likely invalid and it is necessary to apply a correction to estimation procedures. The question of which approaches and specific models are best suited to modeling Acoustic Tag failures has received little research attention. In this short communication, we present a meta-analysis of 42 Acoustic Tag-life studies, originally used to correct survival studies involving outmigrating juvenile salmonids in the Columbia/Snake river basin. We compare the performance of nine alternative parametric models including common failure-time/survival models and vitality models of Li and Anderson (2009 and 2013), which characterize demographic heterogeneity in the mortality of populations. The Tag-life studies used Acoustic Tags from three different Tag manufacturers, had expected lifetimes between 12 and 61 days, and had dry weights ranging from 0.22 to 1.65 grams. In 57% of the cases, the vitality models of Li and Anderson (2009 and 2013) fit the Tag failure-times best. The vitality models were also the second-best choices in 17% of the cases. Together, the vitality models, log-logistic, (19%), and gamma models (14%) accounted for 90% of the models selected. Unlike more traditional failure-time models, the vitality models are capable of characterizing both the early onset of Tag failure due to manufacturing errors and the anticipated battery life. We provide further guidance on appropriate sample sizes (50–100 Tags) and procedures to be considered when applying precise Tag-life corrections in release-recapture survival studies.
Tracey W. Steig - One of the best experts on this subject based on the ideXlab platform.
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Basin-wide monitoring of salmon smolts at US dams
2020Co-Authors: Bruce H. Ransom, Tracey W. Steig, Mark A. Timko, Patrick A. NealsonAbstract:)during their downstream migration to the PacificOcean, Acoustic Tag studies were conducted in 2006throughout the mid-Columbia river, USA. Salmonidruns on the Columbia river and its tributaries havebeen declining as a result of several factors. One con-tributing factor has been the operation of hydropowerdams. Most downstream migrating salmonid smoltspass safely through a single dam; however, the cumu-lative mortality passing through several dams can besignificant [Bell
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Summary of Some Research Developments by Dr. John Ehrenberg in Fisheries Sonar and Acoustic Telemetry over the Last 3 Decades
OCEANS 2019 MTS IEEE SEATTLE, 2019Co-Authors: Tracey W. Steig, Samuel V. Johnston, John E. EhrenbergAbstract:Over the last 30 years, we have been fortunate to work closely with Dr. John Ehrenberg in the fisheries sonar and Acoustic telemetry research fields. With John's passing in the fall of 2018, we felt it was important to honor John's research with this publication. We were involved in multiple research topics with John including: 1) fisheries sonar and telemetry system detectability; 2) characterization of Acoustic Tag signal types and the estimated detection ranges of these signal types; 3) techniques for studying the behavior of fish in a fixed location; 4) theoretical estimation of position accuracy of Acoustic fish Tags; and 5) the development of an Acoustic Tag for sensing and detecting Tagged fish predation. This presentation includes summaries of these research topics. For every application of fisheries sonar sampling technique there are several elements that when combined, affect the probability of detecting fish. They broadly include the following: 1) sampling environment; 2) hydroAcoustic echo sounder sampling parameters; and 3) the behavior and physiology of fish being monitored. Examples will be presented demonstrating the effect of each of these parameters on the ability to detect fish using fisheries sonar. Recent advancements in the implementation, deployment and analysis of Acoustic Tag systems include techniques for optimally locating the receiving hydrophones to minimize location errors, the development of Acoustic signal waveforms that provide unique target identification, accurate location estimates and optimize detection ranges, as well as the development of tracking algorithms that associate and track the multiple returns from an individual fish. These various techniques will be described. Acoustic telemetry systems are often used to study the movement of fish in a region of interest. A method has been developed for predicting the accuracy of the position estimates provided by Acoustic Tag systems. This approach provides a method for the direct calculation of the position error as a function of hydrophone geometry, standard deviation of the signal arrival times, and inaccuracies in the assumed sound velocities. This method is independent of the algorithm used to determine the position solution. Multiple Acoustic-Tag signal-encoding schemes have been implemented for Tag systems. The relationship between the various characteristics of Acoustic signals transmitted by the Tags and the Tag-system performance that can be achieved will be presented. Implemented Tag signal types impact the ranges at which Tags can be detected and uniquely identified, the positional accuracy, as well as the number of unique codes that can be identified. Pulse-repetition period Tag encoding schemes have been demonstrated to provide superior Tag detection range performance relative to schemes employing binary-encoded bits as part of the transmitter signal. The parametric results presented will assist investigators in their selection of the type of Acoustic Tags or Tag parameters needed to achieve the objectives of individual fisheries Acoustic telemetry studies. Acoustic Tags are also often employed to estimate fish survival along a migration route. These studies assume that the Acoustically Tagged fish is alive as the fish passes a detection site. However, if Tagged fish are preyed upon by other fish, the Tag continues to operate, thus providing incorrect data for estimating survival. An Acoustic Tag has been developed to detect predation events and change its signal so that the collected data indicates the occurrence of predation. Examples of predation events signal will be presented.
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A method for estimating the “position accuracy” of Acoustic fish Tags
Journal of Materials Science, 2012Co-Authors: John E. Ehrenberg, Tracey W. SteigAbstract:Acoustic Tag systems have been used for many years to study the behavior of fish in specific areas of interest. In particular Tag systems are being used successfully to study the behavior of downstream migrating salmon smolts (Oncorhynchus spp.) as they approach hydro-electric dams. While field studies have demonstrated the potential for Acoustic Tag systems, little has been done to quantify their performance. This paper develops a method for predicting the accuracy of the “position estimates” provided by Acoustic Tag systems. General expressions are developed that can be applied to any particular deployment of a Tag system which lead onto a method for the direct calculation of the “position error” as a function of hydrophone geometry, standard deviation of the signal arrival times, and the inaccuracies in the assumed sound velocities. This method is independent of the algorithm used to determine the position solution. Using the methods of analysis developed here some specific examples are presented that provide general guidelines that should be followed to achieve good performance when deploying an Acoustic Tag system.
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Improved techniques for studying the temporal and spatial behavior of fish in a fixed location
ICES Journal of Marine Science, 2003Co-Authors: John E. Ehrenberg, Tracey W. SteigAbstract:There are many situations when it is important to know accurately the behavior of fish as a function of time and space in a fixed, three-dimensional volume. One example is the optimal design of techniques that minimize the mortality of fish approaching hydroelectric dams or the cooling intakes of a power plant. The behavior of fish in other fixed volumes, such as estuaries and open rivers, is also of interest in the case of many migrating fish stocks. Both active (echosounding) and passive systems based on Acoustic-emitting Tags implanted in fish have been used to collect behavioral data. Active Acoustic systems, including those with electronically and mechanically steered beams, only insonify a small part of the total volume of interest at any given time. Tag systems, on the other hand, can be used to monitor the behavior of Tagged fish over the entire volume. A number of advances in the implementation, deployment, and analysis of Acoustic-Tag systems have been made over the past few years. These improvements include techniques for positioning optimally the receiving hydrophones to minimize the location measurement errors, the development of Acoustic-signal waveforms that provide both unique target identification and accurate location estimates, and the development of tracking algorithms that associate and track the multiple returns from an individual fish. These various techniques are described. Guidelines are presented for selecting the various parameters for the Tag system, including the positions of the hydrophones. Specific examples that compare the predicted and actual performance of the Tag systems are described. © 2003 International Council for the Exploration of the Sea. Published by Elsevier Science Ltd. All rights reserved.
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New system for remotely monitoring the three‐dimensional movement of Acoustically Tagged fish
Journal of the Acoustical Society of America, 2001Co-Authors: Tracey W. Steig, Samuel V. Johnston, Bruce H. RansomAbstract:A passive Acoustic Tag system was developed to monitor the three‐dimensional movements of migrating fish with submeter resolution. The Acoustic Tag receiver monitors an array consisting of up to 16 omnidirectional hydrophones, with received signals synchronized to determine the arrival times for each pulse transmitted by the Acoustic Tag. Arrival times are then used to calculate the three‐dimensional position of a Tagged fish as it moves through the array. Algorithms were developed to precisely calculate the three‐dimensional positions of the hydrophones, and of each Acoustic Tag. Over the last 4 years, this system was used at several dams in the United States. Most studies to date monitored downstream migrating juvenile salmonids as they approached and passed turbine intakes, spillways, and juvenile bypass systems at hydroelectric dams. Fish movement patterns were tracked in three dimensions over time, typically with submeter resolution. Tagged fish were 160–240 mm long. Acoustic Tags were approximately 7 mm in diameter by 23 mm long, weighted 2 g, and transmitted at 307 kHz. Tag codes (up to 500), pulse width (typically 1–5 ms), and ping rate (typically 0.3–3 pings/s) were field programmable. Current Tags incorporate signal encoding for an improved signal‐to‐noise ratio, and weigh as little as 1 g.
John R. Skalski - One of the best experts on this subject based on the ideXlab platform.
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vitality models found useful in modeling Tag failure times in Acoustic Tag survival studies
Animal Biotelemetry, 2020Co-Authors: John R. Skalski, Steven L. WhitlockAbstract:Acoustic telemetry studies often rely on the assumption that premature Tag failure does not affect the validity of inferences. However, in some cases this assumption is possibly or likely invalid and it is necessary to apply a correction to estimation procedures. The question of which approaches and specific models are best suited to modeling Acoustic Tag failures has received little research attention. In this short communication, we present a meta-analysis of 42 Acoustic Tag-life studies, originally used to correct survival studies involving outmigrating juvenile salmonids in the Columbia/Snake river basin. We compare the performance of nine alternative parametric models including common failure–time/survival models and the vitality models of Li and Anderson Theor Popul Biol 76:118–131, (2009) and Demogr Res 28:341–372, (2013). The Tag-life studies used Acoustic Tags from three different Tag manufacturers, had expected lifetimes between 12 and 61 days, and had dry weights ranging from 0.22 to 1.65 g. In 57% of the cases, the vitality models of Li and Anderson Theor Popul Biol 76:118–131, (2009) and Demogr Res 28:341–372, (2013) fit the Tag-failure times best. The vitality models were also the second-best choices in 17% of the cases. Together, the vitality models, log-logistic, (19%), and gamma models (14%) accounted for 90% of the models selected. Unlike more traditional failure–time models (e.g., Weibull, Gompertz, gamma, and log-logistic), the vitality models are capable of characterizing both the early onset of Tag failure due to manufacturing errors and the anticipated battery life. We provide further guidance on appropriate sample sizes (50–100 Tags) and procedures to be considered when applying precise Tag-life corrections in release–recapture survival studies.
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Vitality Models Found Useful in Modeling Tag-Failure Times in Acoustic-Tag Survival Studies
2020Co-Authors: John R. Skalski, Steven L. WhitlockAbstract:Abstract Acoustic telemetry studies often rely on the assumption that premature Tag failure does not affect the validity of inferences. However, in some cases this assumption is possibly or likely invalid and it is necessary to apply a correction to estimation procedures. The question of which approaches and specific models are best suited to modeling Acoustic Tag failures has received little research attention. In this short communication, we present a meta-analysis of 42 Acoustic Tag-life studies, originally used to correct survival studies involving outmigrating juvenile salmonids in the Columbia/Snake river basin. We compare the performance of nine alternative parametric models including common failure-time/survival models and the vitality models of Li and Anderson (2009 and 2013). The Tag-life studies used Acoustic Tags from three different Tag manufacturers, had expected lifetimes between 12 and 61 days, and had dry weights ranging from 0.22 to 1.65 grams. In 57% of the cases, the vitality models of Li and Anderson (2009 and 2013) fit the Tag failure-times best. The vitality models were also the second-best choices in 17% of the cases. Together, the vitality models, log-logistic, (19%), and gamma models (14%) accounted for 90% of the models selected. Unlike more traditional failure-time models (e.g., Weibull, Gompertz, gamma, and log-logistic), the vitality models are capable of characterizing both the early onset of Tag failure due to manufacturing errors and the anticipated battery life. We provide further guidance on appropriate sample sizes (50–100 Tags) and procedures to be considered when applying precise Tag-life corrections in release-recapture survival studies.
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Vitality Models Found Useful in Modeling Tag-Failure Times in Acoustic-Tag Survival Studies
2020Co-Authors: John R. Skalski, Steven L. WhitlockAbstract:Abstract Acoustic telemetry studies often rely on the assumption that premature Tag failure does not affect the validity of inferences. However, in some cases this assumption is possibly or likely invalid and it is necessary to apply a correction to estimation procedures. The question of which approaches and specific models are best suited to modeling Acoustic Tag failures has received little research attention. In this short communication, we present a meta-analysis of 42 Acoustic Tag-life studies, originally used to correct survival studies involving outmigrating juvenile salmonids in the Columbia/Snake river basin. We compare the performance of nine alternative parametric models including common failure-time/survival models and vitality models of Li and Anderson (2009 and 2013), which characterize demographic heterogeneity in the mortality of populations. The Tag-life studies used Acoustic Tags from three different Tag manufacturers, had expected lifetimes between 12 and 61 days, and had dry weights ranging from 0.22 to 1.65 grams. In 57% of the cases, the vitality models of Li and Anderson (2009 and 2013) fit the Tag failure-times best. The vitality models were also the second-best choices in 17% of the cases. Together, the vitality models, log-logistic, (19%), and gamma models (14%) accounted for 90% of the models selected. Unlike more traditional failure-time models, the vitality models are capable of characterizing both the early onset of Tag failure due to manufacturing errors and the anticipated battery life. We provide further guidance on appropriate sample sizes (50–100 Tags) and procedures to be considered when applying precise Tag-life corrections in release-recapture survival studies.
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The effects of high detection probabilities on model selection in paired release-recapture studies in the era of electronic Tagging studies
Animal Biotelemetry, 2013Co-Authors: John R. Skalski, Adam G Seaburg, Rebecca A BuchananAbstract:Background Acoustic-Tag studies with their high to very high detection rates defy traditional statistical wisdom regarding analysis of Tagging studies. Conventional wisdom has been to use a parsimonious model with the fewest parameters that adequately describes the data to estimate survival parameters in release-recapture studies in order to find a reasonable trade-off between precision and accuracy. This quest has generated considerable debate in the statistical community on how to best accomplish this task. Among the debated options are likelihood ratio tests, Bayesian information criterion, Akaike information criterion, and model averaging. Results Our Monte Carlo simulation studies of paired release-recapture, Acoustic-Tag investigations indicate precision is the same if a fully parameterized or a reduced parameter model is used for data analysis if detection probabilities are very high. In addition, the fully parameterized model is robust to heterogeneous survival and detection processes, while a reduced parameter model may be sensitive to misspecification. Conclusions Use fully parameterized, paired release-recapture models when detection probabilities are very high (≥0.90) to analyze Acoustic-Tagging data in order to retain both robustness and precision, and without the subjectivity and ambiguity introduced by the choice and application of model selection techniques.
