Pub Date : 2002-10-29DOI: 10.1109/OCEANS.2002.1191992
R. J. Meyer, T. Montgomery, W. Hughes
New single crystal piezoelectrics were investigated as improved transducer materials. Single crystals take advantage of crystallographic engineering to produce high piezoelectric and electromechanical coupling coefficients. Single crystal lead magnesium niobate-lead titanate (PMN) was substituted for the piezoelectric ceramic section of a tonpilz transducer design, in order to reduce length and improve bandwidth and output power. Predictions and measurements of transmit performances were made for purposes of comparison to a PZT-8 design. ATILA finite element modeling was used to predict vibration modes, coupling coefficient, head displacement, transmit voltage response, and stress levels in the transducer. Tonpilz elements were then fabricated, tested and analyzed. The performance of the single crystal device was shown to provide the same or improved response over the PZT-8 transducer at a reduced transducer length.
{"title":"Tonpilz transducers designed using single crystal piezoelectrics","authors":"R. J. Meyer, T. Montgomery, W. Hughes","doi":"10.1109/OCEANS.2002.1191992","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1191992","url":null,"abstract":"New single crystal piezoelectrics were investigated as improved transducer materials. Single crystals take advantage of crystallographic engineering to produce high piezoelectric and electromechanical coupling coefficients. Single crystal lead magnesium niobate-lead titanate (PMN) was substituted for the piezoelectric ceramic section of a tonpilz transducer design, in order to reduce length and improve bandwidth and output power. Predictions and measurements of transmit performances were made for purposes of comparison to a PZT-8 design. ATILA finite element modeling was used to predict vibration modes, coupling coefficient, head displacement, transmit voltage response, and stress levels in the transducer. Tonpilz elements were then fabricated, tested and analyzed. The performance of the single crystal device was shown to provide the same or improved response over the PZT-8 transducer at a reduced transducer length.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117216305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-10-29DOI: 10.1109/OCEANS.2002.1192147
J. Moseley
This paper presents a plan to improve software engineering processes based on the Carnegie Mellon University Software Engineering Institute Capability Maturity Model. The perspective is from an organization that performs information processing of oceanographic data. The objective of the plan is to create software quality that is repeatable. Special emphasis is given to key process areas that must be addressed and how these areas relate to the production processes of operational oceanography products. Oceanographic organizations that pursue improvements to software engineering processes may realize significant increases in the quality of their software and, as a result, the information and products that their software produces.
{"title":"Improving software engineering processes to support operational oceanography","authors":"J. Moseley","doi":"10.1109/OCEANS.2002.1192147","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1192147","url":null,"abstract":"This paper presents a plan to improve software engineering processes based on the Carnegie Mellon University Software Engineering Institute Capability Maturity Model. The perspective is from an organization that performs information processing of oceanographic data. The objective of the plan is to create software quality that is repeatable. Special emphasis is given to key process areas that must be addressed and how these areas relate to the production processes of operational oceanography products. Oceanographic organizations that pursue improvements to software engineering processes may realize significant increases in the quality of their software and, as a result, the information and products that their software produces.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117227757","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-10-29DOI: 10.1109/OCEANS.2002.1191829
V. Popovich, Y. Ivakin, S. Shaida
The objectives of the paper are a development of a system of rules called "theory of search for moving objects", and a development of a new class of search problems for moving objects within the frames of this system, rather than a selection, classification or enumeration of all published articles, manuals, monographs, tasks statements and other in the theory of search area. The following issues are considered in the paper: (1) analysis and classification of search problems; (2) an axiomatic basis of the research approach; (3) axioms of the theory of search; (4) common theorem of additivity; (5) theorems of multiplicity; and (6) computer prototype for the theory of search. The case of a complex observation system integrated within one carrier is a core of the proposed approach. A case of two different observation systems is considered, when an observation zone for the second system (contact detector like a laser) is approximated as a line or a rectangle. It is possible to determine a probability area of target localization when one or both observation systems detected the target (theorem of multiplicity). A computer prototype of the theory of search for moving objects has been designed based on the object-oriented approach. It appeared to be a useful tool for any theoretical research and a flexible media for the further development of the theory of search for moving objects. It is also shown that it can be implemented for an adequate computer interpretation of search problems.
{"title":"Theory of search for moving objects","authors":"V. Popovich, Y. Ivakin, S. Shaida","doi":"10.1109/OCEANS.2002.1191829","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1191829","url":null,"abstract":"The objectives of the paper are a development of a system of rules called \"theory of search for moving objects\", and a development of a new class of search problems for moving objects within the frames of this system, rather than a selection, classification or enumeration of all published articles, manuals, monographs, tasks statements and other in the theory of search area. The following issues are considered in the paper: (1) analysis and classification of search problems; (2) an axiomatic basis of the research approach; (3) axioms of the theory of search; (4) common theorem of additivity; (5) theorems of multiplicity; and (6) computer prototype for the theory of search. The case of a complex observation system integrated within one carrier is a core of the proposed approach. A case of two different observation systems is considered, when an observation zone for the second system (contact detector like a laser) is approximated as a line or a rectangle. It is possible to determine a probability area of target localization when one or both observation systems detected the target (theorem of multiplicity). A computer prototype of the theory of search for moving objects has been designed based on the object-oriented approach. It appeared to be a useful tool for any theoretical research and a flexible media for the further development of the theory of search for moving objects. It is also shown that it can be implemented for an adequate computer interpretation of search problems.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124808601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-10-29DOI: 10.1109/OCEANS.2002.1192064
P. Gruzinskas, A. Haas, L. Goon
One of the computational technology areas supported by the High Performance Computing Modernization Program is Climate, Weather, and Ocean (CWO) modeling. To this end, state-of-art computing architectures are leveraged against the extremely difficult problem of mathematically modeling and predicting the behavior of a variety of ocean climatological parameters. The problem at hand is the technology to store, retrieve, manipulate, and display these data has not kept pace with the computational technology. During the last five years, we have seen significant cost reductions associated with applying the status quo in visualization techniques to scientific data sets. This is due in large part to the computer gaming industry, driven by the huge profit margins associated with that market. The scientific community has benefited by these advances in low-cost architectures, but only as a by-product of its original intent, which is entertainment. Even so, these low-cost architectures are not designed to handle the scale of data sizes presented by the scientific community and serve only to make inadequate techniques cheaper to field and use. The Naval Oceanographic Office Major Shared Resource Center (NAVO MSRC) Visualization Center is challenged with providing its users state-of-the-art analysis environments for the interrogation of their increasingly large data sets. This paper deals with the data generated by the CWO community, all of whom work with large domains and high resolutions (either vertically, horizontally, or both) that all vary over time. This leads to very large data sets (rows columns layers attribute per cell) for each time step and can challenge even the most powerful architectures when trying to extract or "mine" information from the raw data. As in most visualization applications, the model output deals with physical parameters that are invisible to the naked eye. This means effective methods of display are required for ocean circulation or currents, sea surface height, temperature, salinity, and so on. One analogy, which no doubt started the concept of "data mining", is that the raw data represent a huge block of ore from which gold nuggets of valuable information (features) must be extracted or mined. This paper concerns the technical solutions that were built to solve the challenges described above, including algorithms, data descriptions, and formats.
{"title":"Data mining ocean model output at the Naval Oceanographic Office Shared Resource Center","authors":"P. Gruzinskas, A. Haas, L. Goon","doi":"10.1109/OCEANS.2002.1192064","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1192064","url":null,"abstract":"One of the computational technology areas supported by the High Performance Computing Modernization Program is Climate, Weather, and Ocean (CWO) modeling. To this end, state-of-art computing architectures are leveraged against the extremely difficult problem of mathematically modeling and predicting the behavior of a variety of ocean climatological parameters. The problem at hand is the technology to store, retrieve, manipulate, and display these data has not kept pace with the computational technology. During the last five years, we have seen significant cost reductions associated with applying the status quo in visualization techniques to scientific data sets. This is due in large part to the computer gaming industry, driven by the huge profit margins associated with that market. The scientific community has benefited by these advances in low-cost architectures, but only as a by-product of its original intent, which is entertainment. Even so, these low-cost architectures are not designed to handle the scale of data sizes presented by the scientific community and serve only to make inadequate techniques cheaper to field and use. The Naval Oceanographic Office Major Shared Resource Center (NAVO MSRC) Visualization Center is challenged with providing its users state-of-the-art analysis environments for the interrogation of their increasingly large data sets. This paper deals with the data generated by the CWO community, all of whom work with large domains and high resolutions (either vertically, horizontally, or both) that all vary over time. This leads to very large data sets (rows columns layers attribute per cell) for each time step and can challenge even the most powerful architectures when trying to extract or \"mine\" information from the raw data. As in most visualization applications, the model output deals with physical parameters that are invisible to the naked eye. This means effective methods of display are required for ocean circulation or currents, sea surface height, temperature, salinity, and so on. One analogy, which no doubt started the concept of \"data mining\", is that the raw data represent a huge block of ore from which gold nuggets of valuable information (features) must be extracted or mined. This paper concerns the technical solutions that were built to solve the challenges described above, including algorithms, data descriptions, and formats.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123768226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-10-29DOI: 10.1109/OCEANS.2002.1191940
A. Prytz, M. Heron, D. Burrage, M. Goodberlet
The scanning low frequency radiometer (SLFMR) is a narrow-band (24 MHz) radiometer operating at 1.413 GHz. It uses a Dicke-switched reference load and a null sensor to match a noise temperature to the brightness temperature of a target. A Butler matrix is used to steer an 8 /spl times/ 8 phased array antenna into eight beam directions. Calibration is required to obtain sea surface salinity estimates from the instrument as it is flown over an area to be mapped. Sea surface temperature, sea state, beam incidence angle and downwelling brightness temperature of the air affect the instrument readings. Consideration must also be given to the effect of solar and galactic radiation reflected off the sea surface into the instrument. This paper focuses on instrument calibrations which are needed to account for the effects of various temperatures measured by sensors at key locations within the instrument. Calibration of the SLFMR was performed by Prosensing before delivery, but it became clear that re-calibration was necessary for each flying campaign. Long-term stability of the instrument and appropriate calibration parameters in light of those suggested by the manufacturer are discussed. These are second-order corrections which arise from small variations in temperature $the whole cabinet has a feedback control loop to hold the cabinet temperature at a nominal 40/spl deg/C. A multivariate linear approach is used to calibrate the instrument for a set of coefficients associated with the temperature measurements. Coefficients were evaluated for all beam positions and checks were made with the SLFMR pointing upwards to scan across known sources of the sun, moon and the centre of the galaxy. Further calculations were made in a room where the target temperature was kept constant. These calibration procedures removed imbalances between the responses at different beam positions. Success of the procedure is demonstrated with some early salinity maps made in the Great Barrier Reef Lagoon in north-east Australia.
{"title":"Calibration of scanning low frequency microwave radiometer","authors":"A. Prytz, M. Heron, D. Burrage, M. Goodberlet","doi":"10.1109/OCEANS.2002.1191940","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1191940","url":null,"abstract":"The scanning low frequency radiometer (SLFMR) is a narrow-band (24 MHz) radiometer operating at 1.413 GHz. It uses a Dicke-switched reference load and a null sensor to match a noise temperature to the brightness temperature of a target. A Butler matrix is used to steer an 8 /spl times/ 8 phased array antenna into eight beam directions. Calibration is required to obtain sea surface salinity estimates from the instrument as it is flown over an area to be mapped. Sea surface temperature, sea state, beam incidence angle and downwelling brightness temperature of the air affect the instrument readings. Consideration must also be given to the effect of solar and galactic radiation reflected off the sea surface into the instrument. This paper focuses on instrument calibrations which are needed to account for the effects of various temperatures measured by sensors at key locations within the instrument. Calibration of the SLFMR was performed by Prosensing before delivery, but it became clear that re-calibration was necessary for each flying campaign. Long-term stability of the instrument and appropriate calibration parameters in light of those suggested by the manufacturer are discussed. These are second-order corrections which arise from small variations in temperature $the whole cabinet has a feedback control loop to hold the cabinet temperature at a nominal 40/spl deg/C. A multivariate linear approach is used to calibrate the instrument for a set of coefficients associated with the temperature measurements. Coefficients were evaluated for all beam positions and checks were made with the SLFMR pointing upwards to scan across known sources of the sun, moon and the centre of the galaxy. Further calculations were made in a room where the target temperature was kept constant. These calibration procedures removed imbalances between the responses at different beam positions. Success of the procedure is demonstrated with some early salinity maps made in the Great Barrier Reef Lagoon in north-east Australia.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116097994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-10-29DOI: 10.1109/OCEANS.2002.1191841
D. DelBalzo, K.P. Hemsteter, E. R. Rike, M.D. Wagstafff, J. Leclere
A successful anti-submarine warfare search planning tool, the Genetic Range-dependent Algorithm for Search Planning (GRASP), is adapted and evaluated for the purpose of planning near-optimal reconnaissance plans for the mine counter-measures community. High-fidelity range- and azimuth-dependent sonar performance predictions over a high-resolution grid are ingested by a genetic algorithm, which uses Monte Carlo simulation and Bayesian detection statistics, to evaluate and refine proposed search paths against a given target distribution. In essence, GRASP simulates a Darwinian evolution of reconnaissance paths to obtain the statistically best path based on Cumulative Detection Probability (CDP). In previous proof-of-concept work, GRASP provided a ladder-like solution in an environment where such solution was expected by search theory. Further, as the environment was perturbed slightly (just outside the bounds for which search theory can determine the optimal path), GRASP produced a path that was a variant on, and an improvement over, the intuitively expected path. In the present work, the efficiencies of acoustically blind and acoustically sensitive mine clearance strategies are compared in a real environment. The GRASP results reveal improvement in search coverage obtained by exploiting the environment with respect to sonar performance.
{"title":"Environmental effects on MCM tactics planning","authors":"D. DelBalzo, K.P. Hemsteter, E. R. Rike, M.D. Wagstafff, J. Leclere","doi":"10.1109/OCEANS.2002.1191841","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1191841","url":null,"abstract":"A successful anti-submarine warfare search planning tool, the Genetic Range-dependent Algorithm for Search Planning (GRASP), is adapted and evaluated for the purpose of planning near-optimal reconnaissance plans for the mine counter-measures community. High-fidelity range- and azimuth-dependent sonar performance predictions over a high-resolution grid are ingested by a genetic algorithm, which uses Monte Carlo simulation and Bayesian detection statistics, to evaluate and refine proposed search paths against a given target distribution. In essence, GRASP simulates a Darwinian evolution of reconnaissance paths to obtain the statistically best path based on Cumulative Detection Probability (CDP). In previous proof-of-concept work, GRASP provided a ladder-like solution in an environment where such solution was expected by search theory. Further, as the environment was perturbed slightly (just outside the bounds for which search theory can determine the optimal path), GRASP produced a path that was a variant on, and an improvement over, the intuitively expected path. In the present work, the efficiencies of acoustically blind and acoustically sensitive mine clearance strategies are compared in a real environment. The GRASP results reveal improvement in search coverage obtained by exploiting the environment with respect to sonar performance.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"20 17 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122313373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-10-29DOI: 10.1109/OCEANS.2002.1192055
A. Morrison, A. Williams, A. Waterbury, C. Tierney
The Modular Acoustic Velocity Sensor, MAVS, measures flow components along four acoustic axes and digitizes acoustic travel-time differences that are then stored and transmitted digitally. This requires an interface to a PC or other digital data acquisition system. Analog outputs, however, free a multi-sensor data acquisition system from the timing requirements and serial input formatting requirements of an array of autonomous digital sensors. A digital to analog output circuit was added to an existing MAVS3 current meter to provide such an output for use in an array of nine MAVS3 sensors in a wave flume. While a sequence from analog to digital to analog seems awkward, it is in fact a very simple and effective means to provide asynchronous data to an existing data acquisition system. The introduction of bit noise in the conversion sequence is more than compensated for by the smoothing of the low pass filter on the analog output from the oversampled digital input. Measuring at 35 Hz with a 16 Hz low pass filter provides a signal that can be digitized without degradation and at a sampling schedule determined by the logger.
{"title":"Analog output from a differential travel-time current meter","authors":"A. Morrison, A. Williams, A. Waterbury, C. Tierney","doi":"10.1109/OCEANS.2002.1192055","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1192055","url":null,"abstract":"The Modular Acoustic Velocity Sensor, MAVS, measures flow components along four acoustic axes and digitizes acoustic travel-time differences that are then stored and transmitted digitally. This requires an interface to a PC or other digital data acquisition system. Analog outputs, however, free a multi-sensor data acquisition system from the timing requirements and serial input formatting requirements of an array of autonomous digital sensors. A digital to analog output circuit was added to an existing MAVS3 current meter to provide such an output for use in an array of nine MAVS3 sensors in a wave flume. While a sequence from analog to digital to analog seems awkward, it is in fact a very simple and effective means to provide asynchronous data to an existing data acquisition system. The introduction of bit noise in the conversion sequence is more than compensated for by the smoothing of the low pass filter on the analog output from the oversampled digital input. Measuring at 35 Hz with a 16 Hz low pass filter provides a signal that can be digitized without degradation and at a sampling schedule determined by the logger.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"73 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122792020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-10-29DOI: 10.1109/OCEANS.2002.1192077
K. Yip, R. Reid
An estimation of wind driven Ekman current and geostrophic current over the Texas-Louisiana (TX-LA) continental shelf is demonstrated in this paper. One should expect the current field is a combination of two parts (G and E). Part G is the near surface part of the geostrophic current generated by the broad-scale wind over the shelf, plus possible influence from the offshore eddies. Part E is the near surface current produced by local Ekman dynamics. One should also expect that the direction and magnitude of part E is controlled by the local wind vector, while part G will tend to be constrained heavily by the local bathymetry of the shelf, which contributes the largest variance of the total near surface current. In order to indirectly obtain geostrophic current, the Ekman current can be determined using a direct calculation from the local wind stress vector. Since the local wind can be in any direction relative to the local shelf topography, a complex linear regression analysis statistical method to get the Ekman flow correctly over the shelf is used. The data set analyzed to obtain regression coefficient and correlation is simulated surface current time series at selected locations over the TX-LA shelf from September 10 to November 3, 2001, total 65 days in this "long" time series. The complex regression coefficient can also be expressed in polar form as a modulus and phase, where the phase gives the angle between the wind vector and the Ekman current vector. Negative angle representing clockwise rotation of the current vector from wind stress vector should be expected in the northern hemisphere. The observations from Texas Automated Buoy System (TABS) moorings R, B, F, D and J for this 55-day window are also used for comparison.
{"title":"An estimation of Ekman and geostrophic current over the Texas-Louisiana shelf","authors":"K. Yip, R. Reid","doi":"10.1109/OCEANS.2002.1192077","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1192077","url":null,"abstract":"An estimation of wind driven Ekman current and geostrophic current over the Texas-Louisiana (TX-LA) continental shelf is demonstrated in this paper. One should expect the current field is a combination of two parts (G and E). Part G is the near surface part of the geostrophic current generated by the broad-scale wind over the shelf, plus possible influence from the offshore eddies. Part E is the near surface current produced by local Ekman dynamics. One should also expect that the direction and magnitude of part E is controlled by the local wind vector, while part G will tend to be constrained heavily by the local bathymetry of the shelf, which contributes the largest variance of the total near surface current. In order to indirectly obtain geostrophic current, the Ekman current can be determined using a direct calculation from the local wind stress vector. Since the local wind can be in any direction relative to the local shelf topography, a complex linear regression analysis statistical method to get the Ekman flow correctly over the shelf is used. The data set analyzed to obtain regression coefficient and correlation is simulated surface current time series at selected locations over the TX-LA shelf from September 10 to November 3, 2001, total 65 days in this \"long\" time series. The complex regression coefficient can also be expressed in polar form as a modulus and phase, where the phase gives the angle between the wind vector and the Ekman current vector. Negative angle representing clockwise rotation of the current vector from wind stress vector should be expected in the northern hemisphere. The observations from Texas Automated Buoy System (TABS) moorings R, B, F, D and J for this 55-day window are also used for comparison.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129511482","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-10-29DOI: 10.1109/OCEANS.2002.1191926
J. A. McConnell, T. Weber, G. Lauchle, T. Gabrielson
The development of an underwater acoustic intensity probe for high frequency applications (e.g., f /spl sim/ 10 kHz) is presented. The probe measures the acoustic pressure along with two orthogonal components of the particle acceleration; hence, the probe relies on inertial sensing as opposed to a gradient technique. The acoustic pressure is measured with a ring hydrophone that is capped at both ends. The accelerometers are positioned within the internal cavity created by the hydrophone and are oriented to measure sound in the horizontal plane. The probe is negatively buoyant, contains a viscoelastic suspension system, and is positioned within a free-flooding stainless steel cage that contains extensional damping treatments and exhibits a low scattering cross-section. Negative buoyancy results from making the probe small so that it does not scatter the acoustic field over the frequency range of interest nor exhibit any in-band structural modes. The consequence of this action translates into an in-water acceleration sensitivity that is reduced by a factor of two relative to the intrinsic value. The hydrophone has an omni-directional beam pattern and the accelerometers have dipole directivity. Lumped parameter circuit models will be preesented along with performanc data.
{"title":"Development of a high frequency underwater acoustic intensity probe","authors":"J. A. McConnell, T. Weber, G. Lauchle, T. Gabrielson","doi":"10.1109/OCEANS.2002.1191926","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1191926","url":null,"abstract":"The development of an underwater acoustic intensity probe for high frequency applications (e.g., f /spl sim/ 10 kHz) is presented. The probe measures the acoustic pressure along with two orthogonal components of the particle acceleration; hence, the probe relies on inertial sensing as opposed to a gradient technique. The acoustic pressure is measured with a ring hydrophone that is capped at both ends. The accelerometers are positioned within the internal cavity created by the hydrophone and are oriented to measure sound in the horizontal plane. The probe is negatively buoyant, contains a viscoelastic suspension system, and is positioned within a free-flooding stainless steel cage that contains extensional damping treatments and exhibits a low scattering cross-section. Negative buoyancy results from making the probe small so that it does not scatter the acoustic field over the frequency range of interest nor exhibit any in-band structural modes. The consequence of this action translates into an in-water acceleration sensitivity that is reduced by a factor of two relative to the intrinsic value. The hydrophone has an omni-directional beam pattern and the accelerometers have dipole directivity. Lumped parameter circuit models will be preesented along with performanc data.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129808078","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2002-10-29DOI: 10.1109/OCEANS.2002.1192094
Roy Wiegert, Brian Price, Jalal Hyder
Presents field test results from a new vector magnetometer-tensor gradiometer sensor system that is being developed, with support, localization and classification (DLC) of ferrous mines in surf zone/very shallow water environments. The experimental results demonstrate that the gradient contraction approach will provide autonomous sensing platforms with robust, three-dimensional mine detection and localization capabilities at ranges of several metres and at all angles of approach to mine-like magnetic targets. The sensor system's gradient contraction based target localization approach is particularly appropriate for DLC of magnetic targets from high mobility autonomous sensing platforms such as underwater bottom vehicles (or Navy divers) that frequently undergo large changes in velocity and orientation as they search for underwater and buried mines.
{"title":"Magnetic anomaly sensing system for mine countermeasures using high mobility autonomous sensing platforms","authors":"Roy Wiegert, Brian Price, Jalal Hyder","doi":"10.1109/OCEANS.2002.1192094","DOIUrl":"https://doi.org/10.1109/OCEANS.2002.1192094","url":null,"abstract":"Presents field test results from a new vector magnetometer-tensor gradiometer sensor system that is being developed, with support, localization and classification (DLC) of ferrous mines in surf zone/very shallow water environments. The experimental results demonstrate that the gradient contraction approach will provide autonomous sensing platforms with robust, three-dimensional mine detection and localization capabilities at ranges of several metres and at all angles of approach to mine-like magnetic targets. The sensor system's gradient contraction based target localization approach is particularly appropriate for DLC of magnetic targets from high mobility autonomous sensing platforms such as underwater bottom vehicles (or Navy divers) that frequently undergo large changes in velocity and orientation as they search for underwater and buried mines.","PeriodicalId":431594,"journal":{"name":"OCEANS '02 MTS/IEEE","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2002-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124597873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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