With the development of ultra-wide coverage technology,multibeam echo-sounder(MBES)system has put forward higher requirements for localization accuracy and computational efficiency of ray tracing method.The classical ...With the development of ultra-wide coverage technology,multibeam echo-sounder(MBES)system has put forward higher requirements for localization accuracy and computational efficiency of ray tracing method.The classical equivalent sound speed profile(ESSP)method replaces the measured sound velocity profile(SVP)with a simple constant gradient SVP,reducing the computational workload of beam positioning.However,in deep-sea environment,the depth measurement error of this method rapidly increases from the central beam to the edge beam.By analyzing the positioning error of the ESSP method at edge beam,it is discovered that the positioning error increases monotonically with the incident angle,and the relationship between them could be expressed by polynomial function.Therefore,an error correction algorithm based on polynomial fitting is obtained.The simulation experiment conducted on an inclined seafloor shows that the proposed algorithm exhibits comparable efficiency to the original ESSP method,while significantly improving bathymetry accuracy by nearly eight times in the edge beam.展开更多
The inhomogeneous sound speed in seawater causes refraction of sound waves,and the elimination of the refraction effect is essential to the accuracy of underwater acoustic positioning.The raytracing method is an indis...The inhomogeneous sound speed in seawater causes refraction of sound waves,and the elimination of the refraction effect is essential to the accuracy of underwater acoustic positioning.The raytracing method is an indispensable tool for effectively handling problems.However,this method has a conflict between localization accuracy and computational quantity.The equivalent sound speed profile(ESSP)method uses a simple sound speed profile(SSP)instead of the actual complex SSP,which can improve positioning precision but with residual error.The residual error is especially non-negligible in deep water and at large beam incidence angles.By analyzing the residual error of the ESSP method through a simulation,an empirical formula of error is presented.The data collected in the sailing circle mode(large incidence angle)of the South China Sea are used for verification.The experiments show that compared to the ESSP method,the improved algorithm has higher positioning precision and is more efficient than the ray-tracing method.展开更多
BACKGROUND Pulmonary hypertension is a rare cardiopulmonary disease,with an insidious onset that usually worsens rapidly.Amyloid light chain(AL)amyloidosis is a rare systemic disease caused by extracellular deposition...BACKGROUND Pulmonary hypertension is a rare cardiopulmonary disease,with an insidious onset that usually worsens rapidly.Amyloid light chain(AL)amyloidosis is a rare systemic disease caused by extracellular deposition of pathologic,insoluble,and proteinaceous fibrils in organs and tissues;however,it is difficult to diagnose given its varied and nonspecific symptoms.To date,rare cases of amyloidosis with pulmonary hypertension have been reported.Of note,the optimal treatments for cardiac amyloidosis complicated with pulmonary hypertension remain unclear.CASE SUMMARY We report a case of a 51-year-old woman who presented with progressively worsening dyspnea.Transthoracic echocardiography indicated severe pulmonary hypertension.Twenty-seven months after first admission,the patient returned with symptoms of progressive heart failure.A myocardial tissue sample stained with Congo red was positive,and the patient was ultimately diagnosed with AL amyloidosis with cardiac involvement.CONCLUSION Although pulmonary hypertension may be idiopathic,it is frequently associated with other conditions.In rare cases,pulmonary hypertension can be a complication of AL amyloidosis,which should be seriously considered in any adult presenting with nonspecific signs or symptoms of cardiac distress.展开更多
随着信息系统与电力物理系统的深度融合,现有电网系统正在向电力信息物理系统(cyber physical power system,CPPS)发展,CPPS不仅需要应对来自物理层面的破坏,还受到来自信息层面的威胁。针对电网所受的威胁,建立了信息物理层相互耦合的...随着信息系统与电力物理系统的深度融合,现有电网系统正在向电力信息物理系统(cyber physical power system,CPPS)发展,CPPS不仅需要应对来自物理层面的破坏,还受到来自信息层面的威胁。针对电网所受的威胁,建立了信息物理层相互耦合的故障模型,提出了一种综合电力节点重要程度及信息网络拓扑结构的评估指标。在仿真研究中,攻击者对高指标节点进行信息攻击并导致其失效,电网以负荷削减最小量为目标进行优化调度,进而根据所提指标辨识耦合网络脆弱环节。以IEEE-30节点系统作为算例进行分析,仿真结果表明,电力信息物理网络应对随机攻击时具有较高的鲁棒性,但同时高指标节点被蓄意攻击情况下则呈现较高的脆弱性。展开更多
基金The Natural Science Foundation of Shandong Province of China under contract Nos ZR2022MA051 and ZR2020MA090the National Natural Science Foundation of China under contract No.U22A2012+2 种基金China Postdoctoral Science Foundation under contract No.2020M670891the SDUST Research Fund under contract No.2019TDJH103the Talent Introduction Plan for Youth Innovation Team in universities of Shandong Province(innovation team of satellite positioning and navigation)。
文摘With the development of ultra-wide coverage technology,multibeam echo-sounder(MBES)system has put forward higher requirements for localization accuracy and computational efficiency of ray tracing method.The classical equivalent sound speed profile(ESSP)method replaces the measured sound velocity profile(SVP)with a simple constant gradient SVP,reducing the computational workload of beam positioning.However,in deep-sea environment,the depth measurement error of this method rapidly increases from the central beam to the edge beam.By analyzing the positioning error of the ESSP method at edge beam,it is discovered that the positioning error increases monotonically with the incident angle,and the relationship between them could be expressed by polynomial function.Therefore,an error correction algorithm based on polynomial fitting is obtained.The simulation experiment conducted on an inclined seafloor shows that the proposed algorithm exhibits comparable efficiency to the original ESSP method,while significantly improving bathymetry accuracy by nearly eight times in the edge beam.
基金the Natural Science Foundation of Shandong Province of China(No.ZR2022MA051)the China Postdoctoral Science Foundation(No.2020M670891)the SDUST Research Fund(No.2019TDJH103)。
文摘The inhomogeneous sound speed in seawater causes refraction of sound waves,and the elimination of the refraction effect is essential to the accuracy of underwater acoustic positioning.The raytracing method is an indispensable tool for effectively handling problems.However,this method has a conflict between localization accuracy and computational quantity.The equivalent sound speed profile(ESSP)method uses a simple sound speed profile(SSP)instead of the actual complex SSP,which can improve positioning precision but with residual error.The residual error is especially non-negligible in deep water and at large beam incidence angles.By analyzing the residual error of the ESSP method through a simulation,an empirical formula of error is presented.The data collected in the sailing circle mode(large incidence angle)of the South China Sea are used for verification.The experiments show that compared to the ESSP method,the improved algorithm has higher positioning precision and is more efficient than the ray-tracing method.
文摘BACKGROUND Pulmonary hypertension is a rare cardiopulmonary disease,with an insidious onset that usually worsens rapidly.Amyloid light chain(AL)amyloidosis is a rare systemic disease caused by extracellular deposition of pathologic,insoluble,and proteinaceous fibrils in organs and tissues;however,it is difficult to diagnose given its varied and nonspecific symptoms.To date,rare cases of amyloidosis with pulmonary hypertension have been reported.Of note,the optimal treatments for cardiac amyloidosis complicated with pulmonary hypertension remain unclear.CASE SUMMARY We report a case of a 51-year-old woman who presented with progressively worsening dyspnea.Transthoracic echocardiography indicated severe pulmonary hypertension.Twenty-seven months after first admission,the patient returned with symptoms of progressive heart failure.A myocardial tissue sample stained with Congo red was positive,and the patient was ultimately diagnosed with AL amyloidosis with cardiac involvement.CONCLUSION Although pulmonary hypertension may be idiopathic,it is frequently associated with other conditions.In rare cases,pulmonary hypertension can be a complication of AL amyloidosis,which should be seriously considered in any adult presenting with nonspecific signs or symptoms of cardiac distress.
文摘随着信息系统与电力物理系统的深度融合,现有电网系统正在向电力信息物理系统(cyber physical power system,CPPS)发展,CPPS不仅需要应对来自物理层面的破坏,还受到来自信息层面的威胁。针对电网所受的威胁,建立了信息物理层相互耦合的故障模型,提出了一种综合电力节点重要程度及信息网络拓扑结构的评估指标。在仿真研究中,攻击者对高指标节点进行信息攻击并导致其失效,电网以负荷削减最小量为目标进行优化调度,进而根据所提指标辨识耦合网络脆弱环节。以IEEE-30节点系统作为算例进行分析,仿真结果表明,电力信息物理网络应对随机攻击时具有较高的鲁棒性,但同时高指标节点被蓄意攻击情况下则呈现较高的脆弱性。
