Marine Search Research Articles

Effect of Restricting Access to a Suicide Jumping Site

The road to a headland that had become a suicide jumping hotspot was temporarily closed because of construction work. This created an opportunity to assess whether loss of vehicular access would lead to a reduction in suicides and emergency police callouts for threatened suicide at the site. Deaths at the headland were ascertained for a 10 year period before road closure and for 2 years following closure using records from the local police inquest officer, the coroner's pathologist and Marine Search and Rescue. Police provided a list of police callouts for threatened suicide at the site for a 4 year period before closure and for 2 years following closure. Simple rates were compared and incident rate ratios were calculated where possible. There were 13 deaths at the headland involving suicide or open verdicts in the 10 years before access was restricted, and none in the 2 years following road closure. This difference was statistically significant (incident rate difference = 1.3 deaths per year, 95% confidence interval (CI) = 0.6-2.0). No jumping suicides occurred elsewhere in the police district following the road closure. Police callouts for threatened suicide also fell significantly, from 19.3 per year in the 4 years prior to road closure to 9.5 per year for the following 2 years (incident rate ratio = 2.0, 95% CI = 1.2-3.5). Preventing vehicular access to a suicide jumping hotspot was an effective means of suicide prevention at the site. There was no evidence of substitution to other jumping sites.

Real-time Dynamic Simulation of 3D Cloud for Marine Search and Rescue Simulator

As the main scenery of sky, the effect of 3D cloud influences the fidelity of visual system and the immersion effect of simulator. In this paper, based on the work of Y. Dobashi and T. Nishita, small region Cellular Automaton is generated and more realistic cloud simulation is improved. The experimental results show that the visual system of simulator can run in real-time and has a relatively higher refresh rate after changeable 3D cloud being applied.

The role of autonomous underwater vehicles for marine search and rescue operations

The role of autonomous underwater vehicles for marine search and rescue operations

Dynamic space reconfiguration for Bayesian search and tracking with moving targets

This paper presents a technique for dynamically reconfiguring search spaces in order to enable Bayesian autonomous search and tracking missions with moving targets. In particular, marine search and...

Comparison of C-band SAR algorithms to derive surface wind vectors and initial findings in their use in marine search and rescue

This paper presents a comparison of existing algorithms to derive surface winds from synthetic aperture radar (SAR) satellites and investigates their use in drift forecasting for search and rescue purposes. Specifically, SAR-derived winds from RADARSAT-1 and ENVISAT advanced synthetic aperture radar (ASAR) data at 1.5 km resolution are compared with scatterometer-derived winds. Three approaches were used to retrieve the wind vector from the SAR data, including an optimal inversion method combining SAR data and background numerical weather prediction, the geophysical model function CMOD-IFR2 with an a priori wind direction, and a technique that uses the backscatter values corresponding to two neighboring subimages with slightly different incidence angles. Our comparisons of SAR wind mapping with scatterometer winds from QuikSCAT and ERS-2 produced a root mean square error (RMSE) of 1.5 m/s. The optimal inversion method seems very promising and appears to be the best choice for assimilation of SAR-derived winds into operational wind products with respect to the datasets presented here. Additionally, the suitability of SAR imagery for search and rescue operations is reviewed. It is recommended that a method should be explored to automatically assimilate such data into operational search and rescue tools. Use of SAR winds in a search and rescue drift model is shown herein to produce improved drift trajectories on a number of search and rescue targets (e.g., life boat, sail boat, person in water).

Simulation system of telemetering and telecontrol for unmanned aerial vehicle

The unmanned aerial vehicle (UAV) which is capable to observe the Earth has wide applications and large quantities, such as reconnaissance and surveillance, attack on the ground, fire-proof forest, and marine search and rescue, and so on. The system of simulation composed of tracking, navigation, telecontrol, telemetering, and flight control is introduced in this paper. The method of simulation on telemetering and telecontrol, tracking and position, and target observation and tracking is explained.

The Potential for Using Very High Spatial Resolution Imagery for Marine Search and Rescue Surveillance

Recreational boating activities represent one of the highest risk populations in the marine environment. Moreover, there is a trend of increased risk exposure by recreational boaters such as those who undertake adventure tourism, sport fishing/hunting, and personal watercraft (PWC) activities. When trying to plan search and rescue activities, there are data deficiencies regarding inventories, activity type, and spatial location of small, recreational boats. This paper examines the current body of research in the application of remote sensing technology in marine search and rescue. The research suggests commercially available very high spatial resolution satellite (VHSR) imagery can be used to detect small recreational vessels using a sub‐pixel detection methodology. The sub‐pixel detection method utilizes local image statistics based on spatio‐spectral considerations. This methodology would have to be adapted for use with VHSR imagery as it was originally used in hyperspectral imaging. Further, the authors examine previous research on ‘target characterization’ which uses a combination of spectral based classification, and context based feature extraction to generate information such as: length, heading, position, and material of construction for target vessels. This technique is based on pixel‐based processing used in generic digital image processing and computer vision. Finally, a preliminary recreational vessel surveillance system ‐ called Marine Recreational Vessel Reconnaissance (MRV Recon) is tested on some modified VHSR imagery.

Prediction of surface currents and drifter trajectories on the inner Scotian Shelf

The predictive skill of a simple model of surface flow on the Scotian Shelf is assessed using oceanographic data collected in February 1996. The model is forced by wind stress, water density, and sea level along the open boundaries of the model domain. The skill of the model with respect to subtidal variations of alongshore current and bottom pressure is quantified by the ratio γ2 = Var(O − P)/Var(O), where Var(O − P) and Var(O) are the variance of the prediction errors and observations, respectively. Skill is highest for bottom pressure (γ2 = 0.2) followed, in order, by cross‐shelf gradients in bottom pressure (γ2 = 0.5), horizontally averaged currents (0.4 < γ2 < 0.7), and currents at individual current meters (0.6 < γ2 < 1.4). The skill of the model with respect to drifter position is quantified by the search radius, centered on the predicted drifter position, that ensures a 50% chance of locating the drifter. Skill varies significantly with time but is generally highest when the drifter motion is strongest. We conclude with a comparison of the performance of the model against predictions based on the release point of the drifters and the operational scheme presently used to guide marine search and rescue in this region.

航海用レーダとレーダ・トランスポンダを使用した新しい海難救助システムのシミュレーション

This paper reports a computer simulation of a new marine search and rescue system, which is applicable under any weather condition, utilizing the marine radar and radar transponder-SART (Search And Rescue Transponder). The purpose of this simulation is to study the relationship between the search distance and consistency of recognition of the new system under various circumstances. Based on the results obtained from this simulation, the performance of this now can be said: 1. the maximum search distance is 13 nautical miles under condition of Beaufort Scale 8 and Sea State 7, and 2. 10% consistency of recognition under any heavy weather and sea condition is indicated within 10 nautical miles in radius. Also, the simulation results under the same sea conditions as those of the sea trials which were carried out at not so heavy weather conditions coincide with the actual results.

The role of HM Coastguard with particular reference to helicopters

HM Coastguard's main function is the co-ordination of all civil marine search and rescue operations around the coast of the United Kingdom—the area limits corresponding to those set out in the ICAO SAR Plan. To achieve this task the coastguards are so disposed around our coast, on a 24 hour watchkeeping basis, to best receive the distress information and vector the appropriate rescue facility to the scene. There are 550 regular coastguards maintaining 150 regular stations (see map) backed up by over 7000 auxiliary coastguards and 214 auxiliary stations. All regular Coastguard Stations maintain watch on MF and VHF marine distress frequencies, are netted in to their local 999 emergency telephone system and are interconnected by VHF radio and telephone. All Rescue HQs and some strategically placed constantly manned stations are addtionally connected to the PO Telex system with direct lines to their adjacent PO Coast Radio Stations. CG Auxiliary stations, provided with VHF radio and telephone facilities, are only manned at times of casualty risk.

Second law of thermo-dynamics

After a shipwreck (ship collision, explosion, disappearance, etc.), people rely on the marine search and rescue wireless sensor networks (MSR-WSNs) as one key weapon to locate and track drowning targets to save lives and assets. However, due to the complex and dynamic ocean environment, marine sensors could be captured by malicious attackers and then become Byzantine sensors. Byzantine sensors may tamper with the actual sensor data at a fixed or time-varying probability and transmit it to the data fusion center (DFC), which renders the normal localization and tracking function of the search and rescue system downgrade or even fail. To address this issue, we develop a New robust marine mobile Multi-Target LocAlization and Tracking scheme called NMTLAT by eliminating abnormal measurement data from the initial measurement data. NMTLAT works in several steps. By analyzing and mining sensors data and behavior, we firstly employ the information entropy of the system composed of a single sensor and their neighbor sensors to develop an efficient dynamic threshold based Byzantine node identification method. After migrating Byzantine sensors, the DFC utilizes sensor-aware and preprocessed marine data of the beacon or honest sensors to complete target localization and trajectory tracking. Specifically, NMTLAT consists of a novel distributed and cooperative multi-target localization and tracking algorithm using both received signal strength indication (RSSI) and priori information of sensors location. NMTLAT employs the importance sampling method to approximate the posterior probability distribution of the sensors and targets location. Furthermore, when the marine target is outside MSR-WSNs coverage, a piecewise function is utilized to characterize the likelihood of finding a drowning target in the search and rescue sea area. Finally, the Lyapunov’s second stability theorem is adopted to measure the stability of the NMTLAT. Our extensive simulation experiments validate that the NMTLAT performance is superior to existing solutions in various marine search and rescue scenarios.