In this paper, in order to overcome certain limitations of previously commercialized platforms, a new integrated unmanned surface vehicle (USV) and unmanned underwater vehicle (UUV) platform connected via underwater cable capable of acquiring real-time underwater data and long-time operation are studied. A catamaran-type USV was designed to overcome the limitations of an ocean environment and to play the role as the hub of power supply and communication for the integrated platform. Meanwhile, the UUV was designed as torpedo-shaped to minimize hydrodynamic resistance and its hardware design was focused on processing and sending the underwater camera and sonar data. The underwater cable driven by a winch system was installed to supply power from the USV to the UUV and to transmit acquired data form underwater sonar sensor or camera. Different from other previously studied cooperation system of USVs and autonomous underwater vehicles (AUVs), the merit of the proposed system is real-time motion coordination control between the USV and UUV while transmitting large amount of data using the tether cable. The main focus of the study is coordination of the UUV with respect to the global positioning system (GPS) attached at USV and verification of its performance throughout field tests. Waypoint tracking control algorithm was designed and implemented on USV and relative heading, distance control for USV–UUV coordination was implemented to UUV. To ensure the integrity of the coordination control of the integrated platform, a study on accurate measurement system of the relative position between the USV and the UUV by using the GPS and the ultrashort baseline (USBL) device was performed. Individual tests were conducted to verify the performance of USBL and AHRS, which provide the position and heading data of UUV among the sensors mounted on the actual platform, and the effectiveness of the obtained sensor data is presented. Using the accurate measurement system, a number of field tests were conducted to verify the performance of the integrated platform.
Atrial fibrillation (AFib) is a common type of cardiac arrhythmia, characterized by disorganized atrial electrical activity with features of irregularly irregular heart rhythm and often with rapid ventricular response increasing the risk of stroke and heart failure due to tachyarrhythmia. The pathophysiology mechanism of AFib is either triggered by atrial distension, abnormality in conducting system, catecholamine excess, or increased atrial irritation or automaticity. Risk factors include uncontrolled diabetes, obesity, obstructive sleep apnea, hypothyroidism, and certain stimulants. Based on recent research, liver disease has recently been identified as a risk factor for AFib. Considering the progression of chronic liver disease, this literature review aims to investigate and summarize the relationship between liver disease and AFib and explore clinical interventions that can be utilized to prevent AFib aggravation.
We present a case involving an 87-year-old woman who had a hyperkalemic emergency. This condition was further complicated by complete heart block (CHB) and seizure-like activity. This case emphasizes the challenge of differentiating between seizures and convulsive syncope. Achieving an accurate diagnosis is essential for determining the appropriate medical treatment. This case report highlights the various symptoms and complications associated with hyperkalemia, emphasizing the importance of conducting a thorough examination to explore other potential causes. Additionally, it emphasizes the usefulness of the head-upright tilt test (HUTT) as a method to differentiate convulsive syncope from seizures, particularly in cases involving vagal stimulation.
We present a rare case of fibromuscular dysplasia (FMD) manifesting in the mid to distal segment of the left anterior descending (LAD) artery, which led to the development of acute coronary syndrome (ACS) in our patient, highlighting the severe consequences of this vascular disorder. During the investigation of the patient's clinical symptoms, an unexpected incidental finding emerged, indicating bilateral FMD involvement of the renal arteries. This serendipitous discovery underscores the importance of comprehensive evaluation and thorough exploration when managing patients with FMD. We aim to shed light on the intriguing nature of FMD and emphasize the need for vigilant assessment to identify potential multi-vessel abnormalities, even beyond the primary affected site. We also aim to highlight the coronary artery manifestation of FMD as ACS and discuss its medical management.
Human influence on soil formation has dramatically increased as the development of human civilization and industry. Increase of anthropogenic soils induced research of those soils; classification, chemical and physical characteristics and plant growth of anthropogenic soils. However there have been no reports on soil pore properties from the anthropogenic soils so far. Therefore the objectives of this study were to test computer tomography (CT) to characterize physical properties of an anthropogenic paddy field soil and to find differences between natural and anthropogenic paddy field soils. Soil samples of a natural paddy field were taken from Ansung, Gyeonggi-do (Ansung site), and samples of an anthropogenic paddy field were from Gumi in Gyeongsangnam-do (Gasan) where paddy fields were remodeled in 2011-2012. Samples were taken at three different depths and analyzed for routine physical properties and CT scans. CT scan provided 3 dimensional images to calculate pore size, length and tortuosity of soil pores. Fractal analysis was applied to quantify pore structure within soil images. The results of measured physical properties (bulk density, porosity) did not show differences across depths and sites, but hardness and water content had differences. These differences repeated within the results of pore morphology. Top soil samples from both sites had greater pore numbers and sizes than others. Fractal analyses showed that top soils had more heterogeneous pore structures than others. The bottom layer of the Gasan site showed more degradation of pore properties than ploughpan and bottom layers from the Ansung site. These results concluded that anthropogenic soils may have more degraded pore properties as depth increases. The remodeled paddy fields may need more fundamental remediation to improve physical conditions. This study suggests that pore analyses using CT can provide important information of physical conditions from anthropogenic soils.
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