Rationality is a fundamental concept in economics. Most researchers will accept that human beings are not fully rational. Herbert Simon suggested that we are ＂bounded rational＂. However, it is very difficult to quan...Rationality is a fundamental concept in economics. Most researchers will accept that human beings are not fully rational. Herbert Simon suggested that we are ＂bounded rational＂. However, it is very difficult to quantify ＂bounded rationality＂, and therefore it is difficult to pinpoint its impact to all those economic theories that depend on the assumption of full rationality. Ariel Rubinstein proposed to model bounded rationality by explicitly specifying the decision makers＇ decision-making procedures. This paper takes a computational point of view to Rubinstein＇s approach. From a computational point of view, decision procedures can be encoded in algorithms and heuristics. We argue that, everything else being equal, the effective rationality of an agent is determined by its computational power - we refer to this as the computational intelligence determines effective rationality （CIDER） theory. This is not an attempt to propose a unifying definition of bounded rationality. It is merely a proposal of a computational point of view of bounded rationality. This way of interpreting bounded rationality enables us to （computationally） reason about economic systems when the full rationality assumption is relaxed.展开更多
Nowadays, Autonomous Underwater Vehicles(AUVs) are frequently used for exploring the oceans. The hydrodynamics of AUVs moving in the vicinity of the water surface are significantly different at higher depths. In this ...Nowadays, Autonomous Underwater Vehicles(AUVs) are frequently used for exploring the oceans. The hydrodynamics of AUVs moving in the vicinity of the water surface are significantly different at higher depths. In this paper, the hydrodynamic coefficients of an AUV in non-dimensional depths of 0.75, 1, 1.5, 2, and 4D are obtained for movement close to the free-surface. Reynolds Averaged Navier Stokes Equations(RANS) are discretized using the finite volume approach and the water-surface effects modeled using the Volume of Fraction(VOF) method. As the operating speeds of AUVs are usually low, the boundary layer over them is not fully laminar or fully turbulent, so the effect of boundary layer transition from laminar to turbulent flow was considered in the simulations. Two different turbulence/transition models were used: 1) a full-turbulence model, the k-ε model, and 2) a turbulence/transition model, Menter's Transition-SST model. The results show that the Menter's Transition-SST model has a better consistency with experimental results. In addition, the wave-making effects of these bodies are studied at different immersion depths in the sea-surface vicinity or at finite depths. It is observed that the relevant pitch moments and lift coefficients are non-zero for these axi-symmetric bodies when they move close to the sea-surface. This is not expected for greater depths.展开更多
BACKGROUND ： Digital subtraction angiography （DSA） is always regarded as the golden standard for diagnosis of intracranial aneurysm; however, the procedure is complex, traumatic, expensive and easy to induce vascul...BACKGROUND ： Digital subtraction angiography （DSA） is always regarded as the golden standard for diagnosis of intracranial aneurysm; however, the procedure is complex, traumatic, expensive and easy to induce vascular complication. Three-dimensional computed tomography angiography （3D-CTA） can make up deficiencies of DSA; therefore, it is used in clinical therapy wider and wider. OBJECTIVE ： To evaluate the clinical effect of 3D-CTA on disruption and hemorrhage of intracranial aneurysm pre- and post-operation and compare with the effect of DSA. DESIGN ： Auto-control contrast observation SETTING ： Department of Neurosurgery, Shengjing Hospital of China Medical University PARTICIPANTS ： A number of 106 patients with disruption and hemorrhage of intracranial aneurysm were selected from the Department of Neurosurgery, Shengjing Hospital of China Medical University from January 2003 to April 2006. All patients were diagnosed with cranial operation and consent. There were 47 males and 59 females aged from 3-76 years with the mean age of （47±13） years. Among them, 82 patients had extensive subarachnoid hemorrhage （SAH）, 7 had hemorrhage at longitudinal fissure, and 17 had hemorrhage at ambiens cistema and lateral fissure. Moreover, intraventricular hematocele was accompanied on 13 patients and hematom on 9 patients. METHODS： （1） 3D-CTA examination： Siemens SOMATOM Sensation 64 CT was used in this study. The thickness was 1 mm and interval of reconstruction was 0.8 mm. Localizing section was plainly scanned as the standard of canthus line. Scan ranged from 30 mm below sella to 50 mm above sella. Non-ion contrast medium of Omnipaque 350 （concentration of iodine was 350 g/L） was inserted into anterior vein of elbow with 18G trochar retained with high-pressured injectoc pum. The speed was 4.5 mL/s and the total volume was 80-100 mL with the means of 90 mL. Scan started at 10-20 s after injection of contrast medium. Original image was dealt with Leonardo workstation and retreated with Syngo software. Volume rendering and maximum intensity projection were used to reconstructed images, （2） All 106 patients suffered from occlusion of aneurysm clamp. Before operation, 3D-CTA was undertaken and DSA was followed. After operation, patients were rechecked with 3D-CTA. MAIN OUTCOME MEASURES： Comparisons between 3D-CTA and DSA. RESULTS ： All 106 patients were involved in the final analysis. （1） Examination of 3D-CTA and DSA： Among 118 patients with aneurysm, 110 were checked with 3D-CTA and the detected rate was 93.2% （110/118）. Among other 8 cases, 3 were negative and checked again with DSA; 1 had pericallosal aneurysm, 1 ophthalmic aneurysm, and 1 anterior choroidal artery of aneurysm. 3D-CTA results of other 5 cases were suspicious, and then, they were regarded as having aneurysm with DSA. Before operation, correlation among site, body, neck of aneurysm and peripheral anatomic structure were shown sufficiently. After operation, 82 patients were rechecked with 3D-CTA, which was complete occlusion, precise, unobvious constriction, emphraxis or remains as compared with 3D-CTA those pre-operation. （2） Characteristics of 3D-CTA： With multiple vessels and angles, 3D-CTA observed the relationship between aneurysm neck and carried artery and showed thrombosis in cavity of aneurysm, calcification of aneurysm wall and peripheral structure of vessel at the same time. However, DSA could not detect the reactions mentioned above. It could delete image of cranium, simulate image of operative route, eliminate artifact induced by metal, but not distinguish blood stream direction. Meanwhile, posterior communicating artery was always poor during circle of Willis artery showing. CONCLUSION： （1） 3D-CTA is characterized by simple operation and non-invasive showing vascular stereo structure and correlation. Therefore, it is significant for diagnosis and designing plan of operative approach and focal location pre-operation and evaluating effect post-operation. （2） 3D-CTA does not completely replace DSA on the diagnosis of intracranial aneurysm.展开更多
Diesel particulate matter(DPM) is considered carcinogenic after prolonged exposure. With more dieselpowered equipment used in underground mines, miners' exposure to DPM has become an increasing concern. This paper...Diesel particulate matter(DPM) is considered carcinogenic after prolonged exposure. With more dieselpowered equipment used in underground mines, miners' exposure to DPM has become an increasing concern. This paper used computational fluid dynamics(CFD) method to study DPM distribution based on an experiment conducted by the Diesel Emissions Evaluation Program(DEEP) in Canada. Twenty-four cases were simulated where the emissions from both truck and load-haul-dumps(LHDs) were examined.Each vehicle was placed in two stream wise locations, and the vehicles were oriented either facing or with the rear end toward the main fresh airflow. A species transport model with buoyancy effect was then used to examine the DPM dispersion pattern. High DPM regions were identified downstream,around, and even upstream of diesel engines. This can provide guidelines for good working practices and selection of diesel emission reduction technologies underground.展开更多
The counter-gradient terms in the computations of turbulent fluxes of heat and moisture have been included in the PBL parameterization of a regional model for monsoon prediction. Results show that inclusion of counter...The counter-gradient terms in the computations of turbulent fluxes of heat and moisture have been included in the PBL parameterization of a regional model for monsoon prediction. Results show that inclusion of counter-gradient terms has a marginal impact in the prediction of large scale monsoon circulation and rainfall rates.展开更多
We generalize the computations of the long-range interactions between two parallel stacks of branes to various cases when two stacks of branes are not placed parallel to each other. We classify the nature of interacti...We generalize the computations of the long-range interactions between two parallel stacks of branes to various cases when two stacks of branes are not placed parallel to each other. We classify the nature of interaction(repulsive or attractive) for each special case and this classification can be used to justify the nature of long-range interaction between two complicated brane systems such as brane bound states. We will provide explicit examples in this paper to demonstrate this.展开更多
Objectives To evaluate the anti- ischemic effect of ISDN on the patients with coronary heart disease . The change in the size of the defect area as percentage of the entire myocardium as determined by the unfolded sur...Objectives To evaluate the anti- ischemic effect of ISDN on the patients with coronary heart disease . The change in the size of the defect area as percentage of the entire myocardium as determined by the unfolded surface mapping between the baseline and after ISDN infusion reflects the anti-ischemic effect of ISDN. Methods and Results 99m Tc-MIBI myocardial perfusion SPECT images were acquired, and reconstruction of the bull's eye map and unfolded surface mapping were performed according to the dates of tomography images. In the group (99mTc-MIBI was injected at 30 minutes after the start of ISDN iv drip) : at the 65% threshold value, the percentage of the defect area size in the whole ventricle was 33.01 ± 5.35% at baseline, (28.9 ±5.23)% after ISDN was infused (P < 0.05); at the 55% threshold value, the percentage of the defect area size in the whole ventricle was (22.06±5.58)% at baseline, (19.60±4.07)% after ISDN was infused (P < 0.05); the sum of defect blood ST segments is 60 at baseline, 51 after ISDN was infused. In the group (99mTc-MIBI was injected at 60 minutes after the start of ISDN iv drip): at the 65% threshold value, the percentage of the defect area size in the whole ventricle was (29.20±5.08)% at baseline, (20.81±4.16)% after ISDN was infused (P < 0.001); at the 55% threshold value, the percentage of the defect area size in the whole ventricle was (21.2 ± 5.49)% at baseline, (17.52±5.59)% after ISDN was infused (P < 0.001); the sum of defect blood ST segments is 58 at baseline, 47 after ISDN was infused. In the group (99mTc-MIBI was injected at 150 minutes after the start of ISDN iv drip) : at the 65% threshold value, the percentage of the defect area size in the whole ventricle was (32.87 ±6.46)% at baseline, (20.81±4.16)% after ISDN was infused (P < 0.001); at the 55% threshold value, the percentage of the defect area size in the whole ventricle was (18.42± 5.17)% at baseline, (14.18±3.61)% after ISDN was infused (P< 0.001); the sum of defect blood ST segments was 64 at baseline, 41 after ISDN was infused. Conclusions The unfolded surface mapping of 99mTc- MIBI myocardial perfusion image can be used as a method of quantitatively evaluating the anti-ischemic effect of drugs and ISDN iv drip can improve the blood flow in myocardium (myocardium perfusion).展开更多
The error propagation for general numerical method in ordinarydifferential equations ODEs is studied. Three kinds of convergence, theoretical, numerical and actual convergences, are presented. The various components o...The error propagation for general numerical method in ordinarydifferential equations ODEs is studied. Three kinds of convergence, theoretical, numerical and actual convergences, are presented. The various components of round-off error occurring in floating-point computation are fully detailed. By introducing a new kind of recurrent inequality, the classical error bounds for linear multistep methods are essentially improved, and joining probabilistic theory the “normal” growth of accumulated round-off error is derived. Moreover, a unified estimate for the total error of general method is given. On the basis of these results, we rationally interpret the various phenomena found in the numerical experiments in part I of this paper and derive two universal relations which are independent of types of ODEs, initial values and numerical schemes and are consistent with the numerical results. Furthermore, we give the explicitly mathematical expression of the computational uncertainty principle and expound the intrinsic relation between two uncertainties which result from the inaccuracies of numerical method and calculating machine.展开更多
Simulations of fixed beds having column to particle diameter ratio （D/dp） of 3, 5 and 10 were performed in the creeping, transition and turbulent flow regimes, where Reynolds number （dpVLρL/μL） was varied from 0...Simulations of fixed beds having column to particle diameter ratio （D/dp） of 3, 5 and 10 were performed in the creeping, transition and turbulent flow regimes, where Reynolds number （dpVLρL/μL） was varied from 0.1 to 10,000. The deviations from Ergun＇s equation due to the wall effects, which are important in D/dp 〈 15 beds were well explained by the CFD simulations. Thus, an increase in the pressure drop was observed due to the wall friction in the creeping flow, whereas, in turbulent regime a decrease in the pressure drop was observed due to the channeling near the wall. It was observed that, with an increase in the D/dp ratio, the effect of wall on drag coefficient decreases and drag coefficient nearly approaches to Ergun＇s equation. The predicted drag coefficient values were in agreement with the experimental results reported in the literature, in creeping flow regime, whereas in turbulent flow the difference was within 10-15%.展开更多
A fuzzy framework based on an adaptive network fuzzy inference system（ANFIS） is proposed to evaluate the relative degradation of the basic subthreshold parameters due to hot-carrier effects for nanoscale thin-film d...A fuzzy framework based on an adaptive network fuzzy inference system（ANFIS） is proposed to evaluate the relative degradation of the basic subthreshold parameters due to hot-carrier effects for nanoscale thin-film double-gate（DG） MOSFETs.The effect of the channel length and thickness on the resulting degradation is addressed, and 2-D numerical simulations are used for the elaboration of the training database.Several membership function shapes are developed,and the best one in terms of accuracy is selected.The predicted results agree well with the 2-D numerical simulations and can be efficiently used to investigate the impact of the interface fixed charges and quantum confinement on nanoscale DG MOSFET subthreshold behavior.Therefore,the proposed ANFIS-based approach offers a simple and accurate technique to study nanoscale devices,including the hot-carrier and quantum effects.展开更多
文摘Rationality is a fundamental concept in economics. Most researchers will accept that human beings are not fully rational. Herbert Simon suggested that we are ＂bounded rational＂. However, it is very difficult to quantify ＂bounded rationality＂, and therefore it is difficult to pinpoint its impact to all those economic theories that depend on the assumption of full rationality. Ariel Rubinstein proposed to model bounded rationality by explicitly specifying the decision makers＇ decision-making procedures. This paper takes a computational point of view to Rubinstein＇s approach. From a computational point of view, decision procedures can be encoded in algorithms and heuristics. We argue that, everything else being equal, the effective rationality of an agent is determined by its computational power - we refer to this as the computational intelligence determines effective rationality （CIDER） theory. This is not an attempt to propose a unifying definition of bounded rationality. It is merely a proposal of a computational point of view of bounded rationality. This way of interpreting bounded rationality enables us to （computationally） reason about economic systems when the full rationality assumption is relaxed.
文摘Nowadays, Autonomous Underwater Vehicles(AUVs) are frequently used for exploring the oceans. The hydrodynamics of AUVs moving in the vicinity of the water surface are significantly different at higher depths. In this paper, the hydrodynamic coefficients of an AUV in non-dimensional depths of 0.75, 1, 1.5, 2, and 4D are obtained for movement close to the free-surface. Reynolds Averaged Navier Stokes Equations(RANS) are discretized using the finite volume approach and the water-surface effects modeled using the Volume of Fraction(VOF) method. As the operating speeds of AUVs are usually low, the boundary layer over them is not fully laminar or fully turbulent, so the effect of boundary layer transition from laminar to turbulent flow was considered in the simulations. Two different turbulence/transition models were used: 1) a full-turbulence model, the k-ε model, and 2) a turbulence/transition model, Menter's Transition-SST model. The results show that the Menter's Transition-SST model has a better consistency with experimental results. In addition, the wave-making effects of these bodies are studied at different immersion depths in the sea-surface vicinity or at finite depths. It is observed that the relevant pitch moments and lift coefficients are non-zero for these axi-symmetric bodies when they move close to the sea-surface. This is not expected for greater depths.
文摘BACKGROUND ： Digital subtraction angiography （DSA） is always regarded as the golden standard for diagnosis of intracranial aneurysm; however, the procedure is complex, traumatic, expensive and easy to induce vascular complication. Three-dimensional computed tomography angiography （3D-CTA） can make up deficiencies of DSA; therefore, it is used in clinical therapy wider and wider. OBJECTIVE ： To evaluate the clinical effect of 3D-CTA on disruption and hemorrhage of intracranial aneurysm pre- and post-operation and compare with the effect of DSA. DESIGN ： Auto-control contrast observation SETTING ： Department of Neurosurgery, Shengjing Hospital of China Medical University PARTICIPANTS ： A number of 106 patients with disruption and hemorrhage of intracranial aneurysm were selected from the Department of Neurosurgery, Shengjing Hospital of China Medical University from January 2003 to April 2006. All patients were diagnosed with cranial operation and consent. There were 47 males and 59 females aged from 3-76 years with the mean age of （47±13） years. Among them, 82 patients had extensive subarachnoid hemorrhage （SAH）, 7 had hemorrhage at longitudinal fissure, and 17 had hemorrhage at ambiens cistema and lateral fissure. Moreover, intraventricular hematocele was accompanied on 13 patients and hematom on 9 patients. METHODS： （1） 3D-CTA examination： Siemens SOMATOM Sensation 64 CT was used in this study. The thickness was 1 mm and interval of reconstruction was 0.8 mm. Localizing section was plainly scanned as the standard of canthus line. Scan ranged from 30 mm below sella to 50 mm above sella. Non-ion contrast medium of Omnipaque 350 （concentration of iodine was 350 g/L） was inserted into anterior vein of elbow with 18G trochar retained with high-pressured injectoc pum. The speed was 4.5 mL/s and the total volume was 80-100 mL with the means of 90 mL. Scan started at 10-20 s after injection of contrast medium. Original image was dealt with Leonardo workstation and retreated with Syngo software. Volume rendering and maximum intensity projection were used to reconstructed images, （2） All 106 patients suffered from occlusion of aneurysm clamp. Before operation, 3D-CTA was undertaken and DSA was followed. After operation, patients were rechecked with 3D-CTA. MAIN OUTCOME MEASURES： Comparisons between 3D-CTA and DSA. RESULTS ： All 106 patients were involved in the final analysis. （1） Examination of 3D-CTA and DSA： Among 118 patients with aneurysm, 110 were checked with 3D-CTA and the detected rate was 93.2% （110/118）. Among other 8 cases, 3 were negative and checked again with DSA; 1 had pericallosal aneurysm, 1 ophthalmic aneurysm, and 1 anterior choroidal artery of aneurysm. 3D-CTA results of other 5 cases were suspicious, and then, they were regarded as having aneurysm with DSA. Before operation, correlation among site, body, neck of aneurysm and peripheral anatomic structure were shown sufficiently. After operation, 82 patients were rechecked with 3D-CTA, which was complete occlusion, precise, unobvious constriction, emphraxis or remains as compared with 3D-CTA those pre-operation. （2） Characteristics of 3D-CTA： With multiple vessels and angles, 3D-CTA observed the relationship between aneurysm neck and carried artery and showed thrombosis in cavity of aneurysm, calcification of aneurysm wall and peripheral structure of vessel at the same time. However, DSA could not detect the reactions mentioned above. It could delete image of cranium, simulate image of operative route, eliminate artifact induced by metal, but not distinguish blood stream direction. Meanwhile, posterior communicating artery was always poor during circle of Willis artery showing. CONCLUSION： （1） 3D-CTA is characterized by simple operation and non-invasive showing vascular stereo structure and correlation. Therefore, it is significant for diagnosis and designing plan of operative approach and focal location pre-operation and evaluating effect post-operation. （2） 3D-CTA does not completely replace DSA on the diagnosis of intracranial aneurysm.
基金financial support provided by the Western US Mining Safety and Health Training & Translation Center by the National Institute for Occupational Safety and Health (NIOSH) (Grant No. 1 R25 OH008319)
文摘Diesel particulate matter(DPM) is considered carcinogenic after prolonged exposure. With more dieselpowered equipment used in underground mines, miners' exposure to DPM has become an increasing concern. This paper used computational fluid dynamics(CFD) method to study DPM distribution based on an experiment conducted by the Diesel Emissions Evaluation Program(DEEP) in Canada. Twenty-four cases were simulated where the emissions from both truck and load-haul-dumps(LHDs) were examined.Each vehicle was placed in two stream wise locations, and the vehicles were oriented either facing or with the rear end toward the main fresh airflow. A species transport model with buoyancy effect was then used to examine the DPM dispersion pattern. High DPM regions were identified downstream,around, and even upstream of diesel engines. This can provide guidelines for good working practices and selection of diesel emission reduction technologies underground.
文摘The counter-gradient terms in the computations of turbulent fluxes of heat and moisture have been included in the PBL parameterization of a regional model for monsoon prediction. Results show that inclusion of counter-gradient terms has a marginal impact in the prediction of large scale monsoon circulation and rainfall rates.
基金Supported by National Natural Science Foundation of China under Grant No.11235010
文摘We generalize the computations of the long-range interactions between two parallel stacks of branes to various cases when two stacks of branes are not placed parallel to each other. We classify the nature of interaction(repulsive or attractive) for each special case and this classification can be used to justify the nature of long-range interaction between two complicated brane systems such as brane bound states. We will provide explicit examples in this paper to demonstrate this.
文摘Objectives To evaluate the anti- ischemic effect of ISDN on the patients with coronary heart disease . The change in the size of the defect area as percentage of the entire myocardium as determined by the unfolded surface mapping between the baseline and after ISDN infusion reflects the anti-ischemic effect of ISDN. Methods and Results 99m Tc-MIBI myocardial perfusion SPECT images were acquired, and reconstruction of the bull's eye map and unfolded surface mapping were performed according to the dates of tomography images. In the group (99mTc-MIBI was injected at 30 minutes after the start of ISDN iv drip) : at the 65% threshold value, the percentage of the defect area size in the whole ventricle was 33.01 ± 5.35% at baseline, (28.9 ±5.23)% after ISDN was infused (P < 0.05); at the 55% threshold value, the percentage of the defect area size in the whole ventricle was (22.06±5.58)% at baseline, (19.60±4.07)% after ISDN was infused (P < 0.05); the sum of defect blood ST segments is 60 at baseline, 51 after ISDN was infused. In the group (99mTc-MIBI was injected at 60 minutes after the start of ISDN iv drip): at the 65% threshold value, the percentage of the defect area size in the whole ventricle was (29.20±5.08)% at baseline, (20.81±4.16)% after ISDN was infused (P < 0.001); at the 55% threshold value, the percentage of the defect area size in the whole ventricle was (21.2 ± 5.49)% at baseline, (17.52±5.59)% after ISDN was infused (P < 0.001); the sum of defect blood ST segments is 58 at baseline, 47 after ISDN was infused. In the group (99mTc-MIBI was injected at 150 minutes after the start of ISDN iv drip) : at the 65% threshold value, the percentage of the defect area size in the whole ventricle was (32.87 ±6.46)% at baseline, (20.81±4.16)% after ISDN was infused (P < 0.001); at the 55% threshold value, the percentage of the defect area size in the whole ventricle was (18.42± 5.17)% at baseline, (14.18±3.61)% after ISDN was infused (P< 0.001); the sum of defect blood ST segments was 64 at baseline, 41 after ISDN was infused. Conclusions The unfolded surface mapping of 99mTc- MIBI myocardial perfusion image can be used as a method of quantitatively evaluating the anti-ischemic effect of drugs and ISDN iv drip can improve the blood flow in myocardium (myocardium perfusion).
基金This work was supported by the Knowledge Innovation Key Project of Chinese Academy of Sciences inthe Resource Environment Field (KZCX1-203) Outstanding State Key Laboratory Project (Grant No. 49823002) the National Natural Science Foundation of C
文摘The error propagation for general numerical method in ordinarydifferential equations ODEs is studied. Three kinds of convergence, theoretical, numerical and actual convergences, are presented. The various components of round-off error occurring in floating-point computation are fully detailed. By introducing a new kind of recurrent inequality, the classical error bounds for linear multistep methods are essentially improved, and joining probabilistic theory the “normal” growth of accumulated round-off error is derived. Moreover, a unified estimate for the total error of general method is given. On the basis of these results, we rationally interpret the various phenomena found in the numerical experiments in part I of this paper and derive two universal relations which are independent of types of ODEs, initial values and numerical schemes and are consistent with the numerical results. Furthermore, we give the explicitly mathematical expression of the computational uncertainty principle and expound the intrinsic relation between two uncertainties which result from the inaccuracies of numerical method and calculating machine.
基金One of us (Rupesh Kumar Reddy Guntaka) acknowledges the fellowship support given by the university Grant Commission (UGC),Government of India
文摘Simulations of fixed beds having column to particle diameter ratio （D/dp） of 3, 5 and 10 were performed in the creeping, transition and turbulent flow regimes, where Reynolds number （dpVLρL/μL） was varied from 0.1 to 10,000. The deviations from Ergun＇s equation due to the wall effects, which are important in D/dp 〈 15 beds were well explained by the CFD simulations. Thus, an increase in the pressure drop was observed due to the wall friction in the creeping flow, whereas, in turbulent regime a decrease in the pressure drop was observed due to the channeling near the wall. It was observed that, with an increase in the D/dp ratio, the effect of wall on drag coefficient decreases and drag coefficient nearly approaches to Ergun＇s equation. The predicted drag coefficient values were in agreement with the experimental results reported in the literature, in creeping flow regime, whereas in turbulent flow the difference was within 10-15%.
文摘A fuzzy framework based on an adaptive network fuzzy inference system（ANFIS） is proposed to evaluate the relative degradation of the basic subthreshold parameters due to hot-carrier effects for nanoscale thin-film double-gate（DG） MOSFETs.The effect of the channel length and thickness on the resulting degradation is addressed, and 2-D numerical simulations are used for the elaboration of the training database.Several membership function shapes are developed,and the best one in terms of accuracy is selected.The predicted results agree well with the 2-D numerical simulations and can be efficiently used to investigate the impact of the interface fixed charges and quantum confinement on nanoscale DG MOSFET subthreshold behavior.Therefore,the proposed ANFIS-based approach offers a simple and accurate technique to study nanoscale devices,including the hot-carrier and quantum effects.
