Equipment systems-of-systems （SOS） effectiveness evaluation can provide important reference for construction and optimization of the equipment SoS. After discussing the basic theory and methods of parallel experimen...Equipment systems-of-systems （SOS） effectiveness evaluation can provide important reference for construction and optimization of the equipment SoS. After discussing the basic theory and methods of parallel experiments, we depict an SoS effectiveness analysis and evaluation method using parallel expe- riments theory in detail. A case study is carried out which takes the missile defense system as an example. An artificial system of the missile defense system is constructed with the multi-agent modeling method. Then, single factor, multiple factors and defense position deployment computational experiments are carried out and evaluated with the statistical analysis method. Experiment re- sults show that the altitude of the secondary interception missile is not the key factor which affects SoS effectiveness and putting the defense position ahead will increase defense effectiveness. The case study demonstrates the feasibility of the proposed method.展开更多
The present study aims to investigate the effectiveness of effusion film cooling on an adiabatic flat plate.Cylindrical holes of 301 inclination are used for supplying cold air to the hot primary flow.A non-dimensiona...The present study aims to investigate the effectiveness of effusion film cooling on an adiabatic flat plate.Cylindrical holes of 301 inclination are used for supplying cold air to the hot primary flow.A non-dimensional parameter called the film cooling effectiveness is calculated for studying the influence of the velocity ratio for a continuous array of cooling holes.A new approach by splitting the full coverage of film holes into two zones of cooling rows is presented in this paper.The computational results from the investigation show that there exists strong relationship between velocity ratio and adiabatic film cooling effectiveness.The simulations of two zones indicate that a careful analysis of the distribution of cooling holes can significantly reduce the demand for the supply of cold air.展开更多
BACKGROUND Percutaneous radiofrequency ablation(RFA)is an effective treatment for unresectable hepatocellular carcinoma(HCC)and a minimally invasive alternative to hepatectomy for treating tumour recurrence.RFA is oft...BACKGROUND Percutaneous radiofrequency ablation(RFA)is an effective treatment for unresectable hepatocellular carcinoma(HCC)and a minimally invasive alternative to hepatectomy for treating tumour recurrence.RFA is often performed using contrast-enhanced computed tomography(CECT)and/or ultrasonography.In recent years,angiographic systems with flat panel image detectors and advanced image reconstruction algorithms have broadened the clinical applications of cone-beam computed tomography(CBCT),including RFA.Several studies have shown the effectiveness of using CBCT for immediate treatment assessments and follow-ups.AIM To assess the treatment response to RFA for HCC using CBCT.METHODS Forty-eight patients(44 men;aged 37-89 years)with solitary HCC[median size:3.2(1.2-6.6)cm]underwent RFA and were followed for 25.6(median;13.5-35.2)mo.Image fusion of CBCT and pre-operative CECT or magnetic resonance imaging(MRI)was used for tumour segmentation and needle path and ablation zone planning.Real-time image guidance was provided by overlaying the threedimensional image of the tumour and needle path on the fluoroscopy image.Treatment response was categorized as complete response(CR),partial response(PR),stable disease(SD),or progressive disease(PD).Disease progression,death,time to progression(TTP),and overall survival(OS)were recorded.Kaplan-Meier and Cox regression analyses were performed.RESULTS Initial post-RFA CECT/MRI showed 38 cases of CR(79.2%),10 of PR(20.8%),0 of SD,and 0 of PD,which strongly correlated with the planning estimation(42 CR,87.5%;6 PR,12.5%;0 SD;and 0 PD;accuracy:91.7%,P<0.01).Ten(20.8%)patients died,and disease progression occurred in 31(35.4%,median TTP:12.8 mo)patients,resulting in 12-,24-,and 35-mo OS rates of 100%,81.2%,and 72.2%,respectively,and progression-free survival(PFS)rates of 54.2%,37.1%,and 37.1%,respectively.The median dose-area product of the procedures was 79.05 Gy*cm2(range 40.95-146.24 Gy*cm2),and the median effective dose was 10.27 mSv(range 5.32-19.01 mSv).Tumour size<2 cm(P=0.00展开更多
In this work we consider the problem of shape reconstruction from an unorganized data set which has many important applications in medical imaging, scientific computing, reverse engineering and geometric modelling. Th...In this work we consider the problem of shape reconstruction from an unorganized data set which has many important applications in medical imaging, scientific computing, reverse engineering and geometric modelling. The reconstructed surface is obtained by continuously deforming an initial surface following the Partial Differential Equation (PDE)-based diffusion model derived by a minimal volume-like variational formulation. The evolution is driven both by the distance from the data set and by the curvature analytically computed by it. The distance function is computed by implicit local interpolants defined in terms of radial basis functions. Space discretization of the PDE model is obtained by finite co-volume schemes and semi-implicit approach is used in time/scale. The use of a level set method for the numerical computation of the surface reconstruction allows us to handle complex geometry and even changing topology,without the need of user-interaction. Numerical examples demonstrate the ability of the proposed method to produce high quality reconstructions. Moreover, we show the effectiveness of the new approach to solve hole filling problems and Boolean operations between different data sets.展开更多
文摘Equipment systems-of-systems （SOS） effectiveness evaluation can provide important reference for construction and optimization of the equipment SoS. After discussing the basic theory and methods of parallel experiments, we depict an SoS effectiveness analysis and evaluation method using parallel expe- riments theory in detail. A case study is carried out which takes the missile defense system as an example. An artificial system of the missile defense system is constructed with the multi-agent modeling method. Then, single factor, multiple factors and defense position deployment computational experiments are carried out and evaluated with the statistical analysis method. Experiment re- sults show that the altitude of the secondary interception missile is not the key factor which affects SoS effectiveness and putting the defense position ahead will increase defense effectiveness. The case study demonstrates the feasibility of the proposed method.
文摘The present study aims to investigate the effectiveness of effusion film cooling on an adiabatic flat plate.Cylindrical holes of 301 inclination are used for supplying cold air to the hot primary flow.A non-dimensional parameter called the film cooling effectiveness is calculated for studying the influence of the velocity ratio for a continuous array of cooling holes.A new approach by splitting the full coverage of film holes into two zones of cooling rows is presented in this paper.The computational results from the investigation show that there exists strong relationship between velocity ratio and adiabatic film cooling effectiveness.The simulations of two zones indicate that a careful analysis of the distribution of cooling holes can significantly reduce the demand for the supply of cold air.
文摘BACKGROUND Percutaneous radiofrequency ablation(RFA)is an effective treatment for unresectable hepatocellular carcinoma(HCC)and a minimally invasive alternative to hepatectomy for treating tumour recurrence.RFA is often performed using contrast-enhanced computed tomography(CECT)and/or ultrasonography.In recent years,angiographic systems with flat panel image detectors and advanced image reconstruction algorithms have broadened the clinical applications of cone-beam computed tomography(CBCT),including RFA.Several studies have shown the effectiveness of using CBCT for immediate treatment assessments and follow-ups.AIM To assess the treatment response to RFA for HCC using CBCT.METHODS Forty-eight patients(44 men;aged 37-89 years)with solitary HCC[median size:3.2(1.2-6.6)cm]underwent RFA and were followed for 25.6(median;13.5-35.2)mo.Image fusion of CBCT and pre-operative CECT or magnetic resonance imaging(MRI)was used for tumour segmentation and needle path and ablation zone planning.Real-time image guidance was provided by overlaying the threedimensional image of the tumour and needle path on the fluoroscopy image.Treatment response was categorized as complete response(CR),partial response(PR),stable disease(SD),or progressive disease(PD).Disease progression,death,time to progression(TTP),and overall survival(OS)were recorded.Kaplan-Meier and Cox regression analyses were performed.RESULTS Initial post-RFA CECT/MRI showed 38 cases of CR(79.2%),10 of PR(20.8%),0 of SD,and 0 of PD,which strongly correlated with the planning estimation(42 CR,87.5%;6 PR,12.5%;0 SD;and 0 PD;accuracy:91.7%,P<0.01).Ten(20.8%)patients died,and disease progression occurred in 31(35.4%,median TTP:12.8 mo)patients,resulting in 12-,24-,and 35-mo OS rates of 100%,81.2%,and 72.2%,respectively,and progression-free survival(PFS)rates of 54.2%,37.1%,and 37.1%,respectively.The median dose-area product of the procedures was 79.05 Gy*cm2(range 40.95-146.24 Gy*cm2),and the median effective dose was 10.27 mSv(range 5.32-19.01 mSv).Tumour size<2 cm(P=0.00
基金supported by PRIN-MIUR-Cofin 2006,project,by"Progetti Strategici EF2006"University of Bologna,and by University of Bologna"Funds for selected research topics"
文摘In this work we consider the problem of shape reconstruction from an unorganized data set which has many important applications in medical imaging, scientific computing, reverse engineering and geometric modelling. The reconstructed surface is obtained by continuously deforming an initial surface following the Partial Differential Equation (PDE)-based diffusion model derived by a minimal volume-like variational formulation. The evolution is driven both by the distance from the data set and by the curvature analytically computed by it. The distance function is computed by implicit local interpolants defined in terms of radial basis functions. Space discretization of the PDE model is obtained by finite co-volume schemes and semi-implicit approach is used in time/scale. The use of a level set method for the numerical computation of the surface reconstruction allows us to handle complex geometry and even changing topology,without the need of user-interaction. Numerical examples demonstrate the ability of the proposed method to produce high quality reconstructions. Moreover, we show the effectiveness of the new approach to solve hole filling problems and Boolean operations between different data sets.
