The Experts below are selected from a list of 35139 Experts worldwide ranked by ideXlab platform
R W Mankin - One of the best experts on this subject based on the ideXlab platform.
-
Acoustical detection of early instar rhynchophorus ferrugineus coleoptera curculionidae in canary island date palm phoenix canariensis arecales arecaceae
Florida Entomologist, 2012Co-Authors: Nathan J Herrick, R W MankinAbstract:ABSTRACT The red palm weevil (RPW), Rhynchophorus ferrugineus (Olivier), recently found in Curacao and Aruba, has become an economically significant palm tree pest in many tropical and subtropical regions. By the time a palm infested with RPW displays visible damage, larvae have destroyed much of the trunk internal structure, typically resulting in tree mortality. Acoustic Technology may enable pest managers to detect and treat early RPW infestations before tree mortality, and to reduce unwanted importation and/or exportation of infested palms. Experiments were conducted in Aruba to determine the detectability of sounds produced by early instars in open, urban environments and in enclosures with ca. 10 dB Acoustical shielding. To distinguish RPW signals from background noise, recordings first were analyzed to identify larval sound impulse bursts, trains of 7–199 impulses, 3–30-ms in duration, where impulses within the train were separated by less than 0.25 s. For a burst to be considered a larval sound, i...
-
recent developments in the use of Acoustic sensors and signal processing tools to target early infestations of red palm weevil in agricultural environments1
Florida Entomologist, 2011Co-Authors: R W MankinAbstract:ABSTRACT Much of the damage caused by red palm weevil larvae to date palms, ornamental palms, and palm offshoots could be mitigated by early detection and treatment of infestations. Acoustic Technology has potential to enable early detection, but the short, high-frequency sound impulses produced by red palm weevil larvae can be difficult to distinguish from certain similar sounds produced by other insects or small animals, or by wind-induced tapping noises. Considerable research has been conducted to develop instruments and signal processing software that selectively amplify insect-produced sounds and identify signal features that distinguish sounds produced by a particular target insect from those produced by other causes. Progress has been made in identifying unique spectral and temporal patterns in the sounds produced by larvae during movement and feeding activities. This report describes some of the new instrumentation and signal analyses available for early, reliable detection of red palm weevil larv...
-
detection of anoplophora glabripennis coleoptera cerambycidae larvae in different host trees and tissues by automated analyses of sound impulse frequency and temporal patterns
Journal of Economic Entomology, 2008Co-Authors: R W Mankin, Michael T Smith, J M Tropp, E B Atkinson, D Y JongAbstract:Anoplophora glabripennis (Motschulsky) (Coleoptera: Cerambycidae), an invasive pest quarantined in the United States, is difficult to detect because the larvae feed unseen inside trees. Acoustic Technology has potential for reducing costs and hazards of tree inspection, but development of practical methods for Acoustic detection requires the solution of technical problems involving transmission of resonant frequencies in wood and high background noise levels in the urban environments where most infestations have occurred. A study was conducted to characterize sounds from larvae of different ages in cambium, sapwood, and heartwood of bolts from three host tree species. Larval sounds in all of the tested trees and tissues consisted primarily of trains of brief, 3–10-ms impulses. There were no major differences in the spectral or temporal pattern characteristics of signals produced by larvae of different ages in each tissue, but larval sounds in sapwood often had fewer spectral peaks than sounds in cambium and heartwood. A large fraction, but not all background sounds could be discriminated from larval sounds by automated spectral analyses. In 3-min recordings from infested bolts, trains containing impulses in patterns called bursts occurred frequently, featuring 7–49 impulses separated by small intervals. Bursts were rarely detected in uninfested bolts. The occurrence of bursts was found to predict infestations more accurately than previously used automated spectral analyses alone. Bursts and other features of sounds that are identifiable by automated techniques may ultimately lead to improved pest detection applications and new insight into pest behavior.
Xiaoming Tang - One of the best experts on this subject based on the ideXlab platform.
-
a logging while drilling Acoustic isolation Technology by varying thickness of drill collars at a distance greater than wavelength
Journal of the Acoustical Society of America, 2012Co-Authors: Yuanda Su, Xiaoming TangAbstract:A key Technology for logging while drilling (LWD) Acoustic measurements is the design of an Acoustic isolator to suppress tool waves propagating along the drill collar, such that Acoustic signals from earth formations can be effectively measured under LWD conditions. Up to now, the LWD Acoustic isolation is achieved by periodically cutting grooves along the drill collar between Acoustic transmitter and receivers. Such a technique, although it is effective, reduces the mechanical strength of the drill collar and adds cost to the manufacturing and maintenance of the LWD tool, hindering the application of the LWD Acoustic Technology. We have developed an LWD Acoustic Technology that does not use the groove-cutting design. We utilize the inherent frequency stopband for extensional wave propagation along a cylindrical pipe and effectively broaden the stopband by combining drill pipes of different cross-section areas whose lengths are greater than a wavelength but are shorter than the transmitter-to-receiver distance. After propagation through the combined drill collar system, the stopband in the collar extensional wave is significantly widened and the wave amplitude in the stopband is substantially reduced. Making LWD Acoustic measurements in this widened stopband allows for recording Acoustic signals from the surrounding formation.
-
a logging while drilling Acoustic isolation Technology by varying thickness of drill collars at a distance greater than wavelength
Journal of the Acoustical Society of America, 2012Co-Authors: Yuanda Su, Xiaoming TangAbstract:A key Technology for logging while drilling (LWD) Acoustic measurements is the design of an Acoustic isolator to suppress tool waves propagating along the drill collar, such that Acoustic signals from earth formations can be effectively measured under LWD conditions. Up to now, the LWD Acoustic isolation is achieved by periodically cutting grooves along the drill collar between Acoustic transmitter and receivers. Such a technique, although it is effective, reduces the mechanical strength of the drill collar and adds cost to the manufacturing and maintenance of the LWD tool, hindering the application of the LWD Acoustic Technology. We have developed an LWD Acoustic Technology that does not use the groove-cutting design. We utilize the inherent frequency stopband for extensional wave propagation along a cylindrical pipe and effectively broaden the stopband by combining drill pipes of different cross-section areas whose lengths are greater than a wavelength but are shorter than the transmitter-to-receiver di...
David W Sims - One of the best experts on this subject based on the ideXlab platform.
-
novel Acoustic Technology for studying free ranging shark social behaviour by recording individuals interactions
PLOS ONE, 2010Co-Authors: Tristan L Guttridge, Samuel H Gruber, Jens Krause, David W SimsAbstract:Group behaviours are widespread among fish but comparatively little is known about the interactions between free-ranging individuals and how these might change across different spatio-temporal scales. This is largely due to the difficulty of observing wild fish groups directly underwater over long enough time periods to quantify group structure and individual associations. Here we describe the use of a novel Technology, an animal-borne Acoustic proximity receiver that records close-spatial associations between free-ranging fish by detection of Acoustic signals emitted from transmitters on other individuals. Validation trials, held within enclosures in the natural environment, on juvenile lemon sharks Negaprion brevirostris fitted with external receivers and transmitters, showed receivers logged interactions between individuals regularly when sharks were within 4 m (∼4 body lengths) of each other, but rarely when at 10 m distance. A field trial lasting 17 days with 5 juvenile lemon sharks implanted with proximity receivers showed one receiver successfully recorded association data, demonstrating this shark associated with 9 other juvenile lemon sharks on 128 occasions. This study describes the use of Acoustic underwater proximity receivers to quantify interactions among wild sharks, setting the scene for new advances in understanding the social behaviours of marine animals.
Ryuichi Matsukura - One of the best experts on this subject based on the ideXlab platform.
-
Measurements of swimming angles, density, and sound speed of the krill euphausia pacifica for target strength estimation
Oceans '04 MTS IEEE Techno-Ocean '04 (IEEE Cat. No.04CH37600), 2004Co-Authors: Tohru Mukai, Kohji Iida, Hisayuki Mikami, Y. Ando, Y. Maki, Ryuichi MatsukuraAbstract:In recent years, Acoustic Technology has been used extensively to estimate krill abundance. Acoustic assessment is required to obtain precise estimates of krill target strength (TS). However, predictions of target strength from theoretical scattering models are often influenced by the swimming angle, density, and sound speed contrasts between krill and seawater. Density and sound speed contrasts are known to show annual cycles. In this study, swimming angles and seasonal variations of the specific density and sound speed contrasts of Euphausia pacifica are presented. Biological sampling was carried out during twilight, when the sound-scattering layer migrates up to the surface. Sound speed measurements were performed on a vessel 2 hours after net sampling, using a T-shaped velocimeter with two transducers mounted at the ends of a horizontal tube. The swimming angles and specific densities of E. pacifica were measured at a laboratory within 48 hours of net sampling. The specific densities of the krill were measured using a series of glycerol solutions of variable densities. Moreover, the total lipid content, lipid composition, and fatty acid composition of the krill were analyzed. The swimming angles of the krill varied from 30 to 50 degrees in low illumination condition (0.1 lx). The density and sound speed contrasts changed with the season. These variations depended on the lipid content in the krill body. In particular, the density of the krill changed with the wax ester content. The variations of TS estimated by the distorted-wave Born approximation (DWBA) method will be discussed
-
seasonal variations of density and sound speed contrasts of the krill euphausia pacifica
Journal of the Acoustical Society of America, 2000Co-Authors: Tohru Mukai, Kohji Iida, Hisayuki Mikami, Ryuichi MatsukuraAbstract:In recent years, Acoustic Technology has been used extensively to estimate krill abundance. Acoustic assessment is required to gain a precise estimate of krill target strength. However, predictions of target strength from theoretical scattering models are often influenced by the swimming angles and density of the krill, and sound‐speed contrasts between krill and seawater. Density and sound‐speed contrasts are known to show annual cycles. In this study, seasonal variations of the specific density and sound‐speed contrasts of Euphausia pacifica are presented. Biological sampling was carried out during twilight, when the sound‐scattering layer migrates up to the surface. The specific densities of E. pacifica were measured, using a series of variable density glycerol solutions, within 48 h of net sampling. Sound‐speed measurements were performed 2 hours after net sampling, using a T‐shaped velocimeter with two transducers mounted on the ends of a horizontal tube. In 1999, the seasonal changes in specific den...
Doug S Butterworth - One of the best experts on this subject based on the ideXlab platform.
-
refined estimates of south african pelagic fish biomass from hydro Acoustic surveys quantifying the effects of target strength signal attenuation and receiver saturation
African Journal of Marine Science, 2008Co-Authors: Janet C Coetzee, Dagmar Merkle, C L De Moor, N Twatwa, Manuel Barange, Doug S ButterworthAbstract:The biomass of small pelagic fish species off the coast of South Africa has been monitored since 1984 using hydro-Acoustic survey techniques. These time-series of spawner biomass and recruitment estimates form the basis for management of both the South African sardine Sardinops sagax and anchovy Engraulis encrasicolus resources and are central to the setting of annual total allowable catch levels. However, these survey estimates have, for the most part, been treated as relative indices as there are several biases inherent in Acoustic survey methodology that remain difficult to quantify. Advances in Acoustic Technology together with an improved understanding of the major sources of survey errors have enabled estimation of and correction for biases such as receiver saturation, Acoustic signal attenuation and target strength. Incorporation of these corrections over the entire time-series has resulted in an improved accuracy of Acoustic survey estimates and substantial changes to the biomass estimates of both...
