This article addresses the issues of falling into local optima and insufficient exploration capability in the Arithmetic Optimization Algorithm (AOA), proposing an improved Arithmetic Optimization Algorithm with a mul...This article addresses the issues of falling into local optima and insufficient exploration capability in the Arithmetic Optimization Algorithm (AOA), proposing an improved Arithmetic Optimization Algorithm with a multi-strategy mechanism (BSFAOA). This algorithm introduces three strategies within the standard AOA framework: an adaptive balance factor SMOA based on sine functions, a search strategy combining Spiral Search and Brownian Motion, and a hybrid perturbation strategy based on Whale Fall Mechanism and Polynomial Differential Learning. The BSFAOA algorithm is analyzed in depth on the well-known 23 benchmark functions, CEC2019 test functions, and four real optimization problems. The experimental results demonstrate that the BSFAOA algorithm can better balance the exploration and exploitation capabilities, significantly enhancing the stability, convergence mode, and search efficiency of the AOA algorithm.展开更多
BACKGROUND The incidence of post-endoscopic retrograde cholangiopancreatography(ERCP)cholangitis(PEC)in patients who underwent mechanical lithotripsy(ML)for large stone removal is high(up to 13.3%).One of the main cau...BACKGROUND The incidence of post-endoscopic retrograde cholangiopancreatography(ERCP)cholangitis(PEC)in patients who underwent mechanical lithotripsy(ML)for large stone removal is high(up to 13.3%).One of the main causes is remaining small fragments or sludge that can impair normal biliary drainage.Endoscopic placement of a nasobiliary tube or a conventional plastic biliary stent has been commonly used under such conditions,but the patient may suffer from significant discomfort after the placement of a nasobiliary tube,while additional endoscopy is required for stent removal.We developed a biliary spontaneous dislodgement spiral stent(BSDSS)to overcome those shortcomings.AIM To evaluate the feasibility,safety,and effectiveness of inserting a BSDSS for patients who underwent ML for large stone removal.METHODS We conducted a single-center,retrospective,cohort study at West China Hospital,Sichuan University.A total of 91 consecutive patients with large biliary stones(≥10 mm)in the common bile duct who underwent ML between November 2017 and July 2018 were included.The 49 eligible patients were divided into the BSDSS group and the nasobiliary tube group.Technical success,post-ERCP adverse events(including PEC,post-ERCP pancreatitis,stone recurrence,BSDSS retention,self-extraction and dislocation of the nasobiliary tube),drainage time,and postoperative stay were measured and compared.RESULTS Twenty-one patients in the BSDSS group and 28 patients in the nasobiliary tube group were included in the analyses.The baseline characteristics and clinical information were similar in the two groups.Insertions of BSDSS and nasobiliary tube were technically successful in all 49 patients.There was no significant difference in the incidence of overall post-ERCP adverse events between the two groups(4.8%in the BSDSS group vs 17.9%in the nasobiliary tube group,P=0.219).The median duration of drainage time(3 d in the BSDSS group vs 4 d in the nasobiliary tube group)and length of postoperative stay(4 d in the BSDSS group vs 5 d in the nasobiliary tube group)also did not differ(P=0.934,and P=0.223,respectively).CONCLUSION Endoscopic placement of a BSDSS appears to be feasible,safe and effective for patients who underwent ML for large stone removal.展开更多
Objective.To compare the embolization effects of intracranial aneurysms with mechanical detachable spirals(MDS) and with Guglielmi detachable coils(GDC).Methods.One hundred and twenty cases with 125 intracranial aneur...Objective.To compare the embolization effects of intracranial aneurysms with mechanical detachable spirals(MDS) and with Guglielmi detachable coils(GDC).Methods.One hundred and twenty cases with 125 intracranial aneurysms were embolized in Beijing Hospital from March 1995 to July 1999.Sixty-six aneursms in 64 cases were embolized with MDS,51 in 48 with GDC, and 8 in 8 with both MDS and GDC.Clinical data includng sex,age,subarachnoid hemorrhage(SAH),Hunt & Hess grading,diameter and neck width of aneurysms,number and length of coils used per aneurysm,occlusive radio,and complications were compared between MDS and groups.Results.MDS and GDC groups were comparable(t-test or X^2 -test ,all P value>0.10） in terms of age,sex,diameter of aneurysms[(8.46±3.42)mm vs.(7.38±3.45)mm],neck width[(3.49±1.50)mm vs.（3.26±1.52)mm],coils number [(4.65±3.01)vs.(4.24±2.65)] and their length[(460.2±398.5)mm vs.(422.9±387.1)mm] used per aneurysm,occlusive ratio in aneurysms embolized≥80%[(95.00±6.32%)vs.(94.19%±7.63%)],mortality and permanent complications(7.8% vs.4.25）。Couclusions,MDS and GDC are all materials for embolization of intracranial aneurysms.MDS is less expensive,but more difficult to control and of propensity to complications while GDC is more compliant ,easier to be used,safer,and have many alternative types for use as well as more extensive indications.展开更多
针对长短期记忆(long short term memory,LSTM)神经网络存在短期负荷预测精度低和稳定性差的问题,提出一种基于多策略改进金豺(improved golden jackal optimization,IGJO)算法优化LSTM的短期电力负荷预测模型。首先融合凸透镜成像反向...针对长短期记忆(long short term memory,LSTM)神经网络存在短期负荷预测精度低和稳定性差的问题,提出一种基于多策略改进金豺(improved golden jackal optimization,IGJO)算法优化LSTM的短期电力负荷预测模型。首先融合凸透镜成像反向学习策略,探索更好的初始解位置;引入Sigmoid函数改变逃逸能量,平衡探索和开发阶段;融合鲸鱼优化算法的螺旋包围机制,增强探索能力,提高收敛精度。然后,引入LSTM神经网络,利用IGJO算法优化LSTM的超参数,并建立IGJO-LSTM短期电力负荷预测模型。最后,使用河南某地区的实际电力负荷数据验证IGJO-LSTM短期负荷预测模型。实验结果表明,所提预测模型在工作日和周末不同时刻的电力系统短期负荷预测结果与实际负荷较接近。相比于传统预测方法,所提预测模型具有更高的精确度和稳定性,并具有一定的实际应用潜力。展开更多
Micro electrical discharge machining（EDM） deposition process is a new micro machining method for fabrication of metal micro structures. In this process, the high level of tool electrode wear is used to achieve the m...Micro electrical discharge machining（EDM） deposition process is a new micro machining method for fabrication of metal micro structures. In this process, the high level of tool electrode wear is used to achieve the metal material deposition. Up to now, the studies of micro EDM deposition process focused mainly on the researches of deposition process, namely the effects of discharge parameters in deposition process on the deposition rate or deposition quality. The research of the formation of micro structures with different discharge energy density still lacks. With proper conditions and only by the z-axis feeding in vertical direction, a novel shape of micro spiral structure can be deposited, with 0.11 mm in wire diameter, 0.20 mm in outside diameter, and 3.78 mm in height. Then some new deposition strategies including angular deposition and against the gravity deposition were also successful. In order to find the forming mechanism of the spiral structures, the numerical simulation of the transient temperature distribution on the discharge point was conducted by using the finite-element method（FEM）. The results show that there are two major factors lead to the forming of the spiral structures. One is the different material removal form of tool electrode according with the discharge energy density, the other is the influenced degree of the movement of the removed material particles in the discharge gap. The more the energy density in single discharge is, the smaller the mass of the removed material particles is, and the easier the movements of which will be changed to form an order tendency. The fine texture characteristics of the deposited micro spiral structures were analyzed by the energy spectrum analysis and the metallographic analysis. It shows that the components of the deposited material are almost the same as those of the tool electrode. Moreover the deposited material has the brass metallic luster in the longitudinal profile and has compact bonding with the base material. This research is useful to understand the micro-process of micro EDM deposition better and helpful to increase the controllability of the new EDM method for fabrication of micro structures.展开更多
We hypothesize that gravitons contribute significantly to the process that flattens galaxy rotation curves. Gravitons travelling against a gravitational field experience an energy loss due to gravitational redshift id...We hypothesize that gravitons contribute significantly to the process that flattens galaxy rotation curves. Gravitons travelling against a gravitational field experience an energy loss due to gravitational redshift identical to the effect on light. This energy loss requires an increased rotational velocity to stabilize a galaxy. We will show that this approach successfully explains the rotational properties of spiral and dwarf galaxies.展开更多
文摘This article addresses the issues of falling into local optima and insufficient exploration capability in the Arithmetic Optimization Algorithm (AOA), proposing an improved Arithmetic Optimization Algorithm with a multi-strategy mechanism (BSFAOA). This algorithm introduces three strategies within the standard AOA framework: an adaptive balance factor SMOA based on sine functions, a search strategy combining Spiral Search and Brownian Motion, and a hybrid perturbation strategy based on Whale Fall Mechanism and Polynomial Differential Learning. The BSFAOA algorithm is analyzed in depth on the well-known 23 benchmark functions, CEC2019 test functions, and four real optimization problems. The experimental results demonstrate that the BSFAOA algorithm can better balance the exploration and exploitation capabilities, significantly enhancing the stability, convergence mode, and search efficiency of the AOA algorithm.
文摘BACKGROUND The incidence of post-endoscopic retrograde cholangiopancreatography(ERCP)cholangitis(PEC)in patients who underwent mechanical lithotripsy(ML)for large stone removal is high(up to 13.3%).One of the main causes is remaining small fragments or sludge that can impair normal biliary drainage.Endoscopic placement of a nasobiliary tube or a conventional plastic biliary stent has been commonly used under such conditions,but the patient may suffer from significant discomfort after the placement of a nasobiliary tube,while additional endoscopy is required for stent removal.We developed a biliary spontaneous dislodgement spiral stent(BSDSS)to overcome those shortcomings.AIM To evaluate the feasibility,safety,and effectiveness of inserting a BSDSS for patients who underwent ML for large stone removal.METHODS We conducted a single-center,retrospective,cohort study at West China Hospital,Sichuan University.A total of 91 consecutive patients with large biliary stones(≥10 mm)in the common bile duct who underwent ML between November 2017 and July 2018 were included.The 49 eligible patients were divided into the BSDSS group and the nasobiliary tube group.Technical success,post-ERCP adverse events(including PEC,post-ERCP pancreatitis,stone recurrence,BSDSS retention,self-extraction and dislocation of the nasobiliary tube),drainage time,and postoperative stay were measured and compared.RESULTS Twenty-one patients in the BSDSS group and 28 patients in the nasobiliary tube group were included in the analyses.The baseline characteristics and clinical information were similar in the two groups.Insertions of BSDSS and nasobiliary tube were technically successful in all 49 patients.There was no significant difference in the incidence of overall post-ERCP adverse events between the two groups(4.8%in the BSDSS group vs 17.9%in the nasobiliary tube group,P=0.219).The median duration of drainage time(3 d in the BSDSS group vs 4 d in the nasobiliary tube group)and length of postoperative stay(4 d in the BSDSS group vs 5 d in the nasobiliary tube group)also did not differ(P=0.934,and P=0.223,respectively).CONCLUSION Endoscopic placement of a BSDSS appears to be feasible,safe and effective for patients who underwent ML for large stone removal.
基金This work was originally published in the Chinese Journal of Neuro-surgery (2001 17(2): 87-90) in Chinese.
文摘Objective.To compare the embolization effects of intracranial aneurysms with mechanical detachable spirals(MDS) and with Guglielmi detachable coils(GDC).Methods.One hundred and twenty cases with 125 intracranial aneurysms were embolized in Beijing Hospital from March 1995 to July 1999.Sixty-six aneursms in 64 cases were embolized with MDS,51 in 48 with GDC, and 8 in 8 with both MDS and GDC.Clinical data includng sex,age,subarachnoid hemorrhage(SAH),Hunt & Hess grading,diameter and neck width of aneurysms,number and length of coils used per aneurysm,occlusive radio,and complications were compared between MDS and groups.Results.MDS and GDC groups were comparable(t-test or X^2 -test ,all P value>0.10） in terms of age,sex,diameter of aneurysms[(8.46±3.42)mm vs.(7.38±3.45)mm],neck width[(3.49±1.50)mm vs.（3.26±1.52)mm],coils number [(4.65±3.01)vs.(4.24±2.65)] and their length[(460.2±398.5)mm vs.(422.9±387.1)mm] used per aneurysm,occlusive ratio in aneurysms embolized≥80%[(95.00±6.32%)vs.(94.19%±7.63%)],mortality and permanent complications(7.8% vs.4.25）。Couclusions,MDS and GDC are all materials for embolization of intracranial aneurysms.MDS is less expensive,but more difficult to control and of propensity to complications while GDC is more compliant ,easier to be used,safer,and have many alternative types for use as well as more extensive indications.
文摘针对长短期记忆(long short term memory,LSTM)神经网络存在短期负荷预测精度低和稳定性差的问题,提出一种基于多策略改进金豺(improved golden jackal optimization,IGJO)算法优化LSTM的短期电力负荷预测模型。首先融合凸透镜成像反向学习策略,探索更好的初始解位置;引入Sigmoid函数改变逃逸能量,平衡探索和开发阶段;融合鲸鱼优化算法的螺旋包围机制,增强探索能力,提高收敛精度。然后,引入LSTM神经网络,利用IGJO算法优化LSTM的超参数,并建立IGJO-LSTM短期电力负荷预测模型。最后,使用河南某地区的实际电力负荷数据验证IGJO-LSTM短期负荷预测模型。实验结果表明,所提预测模型在工作日和周末不同时刻的电力系统短期负荷预测结果与实际负荷较接近。相比于传统预测方法,所提预测模型具有更高的精确度和稳定性,并具有一定的实际应用潜力。
基金supported by National Natural Science Foundation of China(Grant No.50675049)
文摘Micro electrical discharge machining（EDM） deposition process is a new micro machining method for fabrication of metal micro structures. In this process, the high level of tool electrode wear is used to achieve the metal material deposition. Up to now, the studies of micro EDM deposition process focused mainly on the researches of deposition process, namely the effects of discharge parameters in deposition process on the deposition rate or deposition quality. The research of the formation of micro structures with different discharge energy density still lacks. With proper conditions and only by the z-axis feeding in vertical direction, a novel shape of micro spiral structure can be deposited, with 0.11 mm in wire diameter, 0.20 mm in outside diameter, and 3.78 mm in height. Then some new deposition strategies including angular deposition and against the gravity deposition were also successful. In order to find the forming mechanism of the spiral structures, the numerical simulation of the transient temperature distribution on the discharge point was conducted by using the finite-element method（FEM）. The results show that there are two major factors lead to the forming of the spiral structures. One is the different material removal form of tool electrode according with the discharge energy density, the other is the influenced degree of the movement of the removed material particles in the discharge gap. The more the energy density in single discharge is, the smaller the mass of the removed material particles is, and the easier the movements of which will be changed to form an order tendency. The fine texture characteristics of the deposited micro spiral structures were analyzed by the energy spectrum analysis and the metallographic analysis. It shows that the components of the deposited material are almost the same as those of the tool electrode. Moreover the deposited material has the brass metallic luster in the longitudinal profile and has compact bonding with the base material. This research is useful to understand the micro-process of micro EDM deposition better and helpful to increase the controllability of the new EDM method for fabrication of micro structures.
文摘We hypothesize that gravitons contribute significantly to the process that flattens galaxy rotation curves. Gravitons travelling against a gravitational field experience an energy loss due to gravitational redshift identical to the effect on light. This energy loss requires an increased rotational velocity to stabilize a galaxy. We will show that this approach successfully explains the rotational properties of spiral and dwarf galaxies.
