Component reallocation(CR)is receiving increasing attention in many engineering systems with functionally interchangeable and unbalanced degradation components.This paper studies a CR and system replacement maintenanc...Component reallocation(CR)is receiving increasing attention in many engineering systems with functionally interchangeable and unbalanced degradation components.This paper studies a CR and system replacement maintenance policy of series repairable systems,which undergoes minimal repairs for each emergency failure of components,and considers constant downtime and cost of minimal repair,CR and system replacement.Two binary mixed integer nonlinear programming models are respectively established to determine the assignment of CR,and the uptime right before CR and system replacement with the objective of minimizing the system average maintenance cost and maximizing the system availability.Further,we derive the optimal uptime right before system replacement with maximization of the system availability,and then give the relationship between the system availability and the component failure rate.Finally,numerical examples show that the CR and system replacement maintenance policy can effectively reduce the system average maintenance cost and improve the system availability,and further give the sensitivity analysis and insights of the CR and system replacement maintenance policy.展开更多
Total Knee Replacement(TKR)is the increasing trend now a day,in revision surgery which is associated with aseptic loosening,which is a challenging research for the TKR component.The selection of optimal material loose...Total Knee Replacement(TKR)is the increasing trend now a day,in revision surgery which is associated with aseptic loosening,which is a challenging research for the TKR component.The selection of optimal material loosening can be controlled at some limits.This paper is going to consider the best material selected among a number of alternative materials for the femoral component(FC)by using Graph Theory.Here GTMA process used for optimization of material and a systematic technique introduced through sensitivity analysis to find out the more reliable result.Obtained ranking suggests the use of optimized material over the other existing material.By following GTMA Co_Cr-alloys(wrought-Co-Ni-Cr-Mo)and Co_Cr-alloys(cast-able-Co-Cr-Mo)are on the 1st and 2nd position respectively.展开更多
BACKGROUND Total hip replacement has become one of the most successful orthopaedic procedures.The length of the femoral stem constitutes one of the most important geometrical and mechanical features of the prosthesis....BACKGROUND Total hip replacement has become one of the most successful orthopaedic procedures.The length of the femoral stem constitutes one of the most important geometrical and mechanical features of the prosthesis.Several different implants are currently available but data are limited concerning the clinical results for some of these implants.AIM To report the short-term clinical and radiological results of a novel squared section,tapered design–with four conicity-short stem in total hip replacement.METHODS This is a retrospective study of a prospectively collected data using of MINIMA?short stem in 61 consecutive patients with at least 1 year follow-up.The collected data included patients’demographics,type of arthritis,bone morphology,perioperative data,clinical results using Harris Hip Score,EuroQol(EQ-5D),pain score and satisfaction rate,complications and radiological results.RESULTS Total 61 patients were included in our study with a mean age of 56 years of age(range 25-73 years).The majority of them(68.6%)were women,thirty seven patients(56.9%)were less than 60 years of age and almost half of patients(45.1%)suffered from secondary osteoarthritis(hip dysplasia,osteonecrosis,etc.).The mean time of follow-up examination was 33.4 mo(2.8 years)with a range of 12-57 months(1-4.8 years).In 35 patients(56.9%)the follow-up examination was more than 3 years.No major complications such as revision,periprosthetic fracture,dislocation or infection were presented.Re-admission 90 d postoperatively or laterwas deemed unnecessary for any reason regarding the operation.Respectively,the mean pain score,mean Harris hip score,and mean EQ-5D were improved from 6.3,58.7 and 77.3 preoperatively to 0.1,95.1,and 79.8 postoperatively.The Satisfaction rate at the final follow-up was 9.9(SD 0.3,range 8.0-10.0).All stems were classified as stable bone ingrowth and no radiolucent lineswere revealed in any of the modified Gruens’zone at the postoperative Xrays.Stem subsidence was within acceptable limits and the incidence of distal cortical hypertrophy was relatively low.CONCLUSION The clinical and radiological results concerning the MINIMA?short stem are excellent according to this first report of this specific design of the short femoral stems.Because of the small number of cases and short-term follow-up of this study,a longer follow up time and more patients’enrollment is required.展开更多
The restaurant is traditional industry of the third industry in our country. Since May 1 in this year, China＇s Restaurant Industry to implement ＂replace the business tax with value-added tax＂ policy and change to p...The restaurant is traditional industry of the third industry in our country. Since May 1 in this year, China＇s Restaurant Industry to implement ＂replace the business tax with value-added tax＂ policy and change to pay VAT. This paper analyzed the possible impact on restaurant industry after the＂ replace the business tax with value-added tax＂ based on the understanding of the tax theory of＂ replace the business tax with value-added tax＂ and the tax compliance in our country. At the same time, this paper used the statistical analysis of data on the investigation of 100 samples of the VAT cognitive degree on ＂replace the business tax with value-added tax＂, using principal component analysis method to analyze and evaluate factors on the awareness of the restaurant owner to ＂replace the business tax with value-added tax＂ tax policy. After multiple comparison made on the sample data, this paper summarized and analyzed the countermeasures of improving the pushing effect in restaurant industry ＂replace the business tax with VAT ＂.展开更多
We consider a replacement policy for a multiple-component cold-standbysystem, and after we analyze this policy, we want to get the mean total cost rate and the preventivepolicy to make it the lowest. In this system, t...We consider a replacement policy for a multiple-component cold-standbysystem, and after we analyze this policy, we want to get the mean total cost rate and the preventivepolicy to make it the lowest. In this system, the failure rate of the component in operation isconstant, and the inspection will control all the processes of the operation. The system isinspected at random points over time to determine whether it is to be replaced. During the process,the replacement decision is based on the number of failed components at the time of inspection.展开更多
基金supported by the National Natural Science Foundation of China(72101025,72271049)the Fundamental Research Funds for the Central Universities(FRF-TP-20-073A1)the China Postdoct oral Science Foundation(2021M690349)。
文摘Component reallocation(CR)is receiving increasing attention in many engineering systems with functionally interchangeable and unbalanced degradation components.This paper studies a CR and system replacement maintenance policy of series repairable systems,which undergoes minimal repairs for each emergency failure of components,and considers constant downtime and cost of minimal repair,CR and system replacement.Two binary mixed integer nonlinear programming models are respectively established to determine the assignment of CR,and the uptime right before CR and system replacement with the objective of minimizing the system average maintenance cost and maximizing the system availability.Further,we derive the optimal uptime right before system replacement with maximization of the system availability,and then give the relationship between the system availability and the component failure rate.Finally,numerical examples show that the CR and system replacement maintenance policy can effectively reduce the system average maintenance cost and improve the system availability,and further give the sensitivity analysis and insights of the CR and system replacement maintenance policy.
文摘Total Knee Replacement(TKR)is the increasing trend now a day,in revision surgery which is associated with aseptic loosening,which is a challenging research for the TKR component.The selection of optimal material loosening can be controlled at some limits.This paper is going to consider the best material selected among a number of alternative materials for the femoral component(FC)by using Graph Theory.Here GTMA process used for optimization of material and a systematic technique introduced through sensitivity analysis to find out the more reliable result.Obtained ranking suggests the use of optimized material over the other existing material.By following GTMA Co_Cr-alloys(wrought-Co-Ni-Cr-Mo)and Co_Cr-alloys(cast-able-Co-Cr-Mo)are on the 1st and 2nd position respectively.
文摘BACKGROUND Total hip replacement has become one of the most successful orthopaedic procedures.The length of the femoral stem constitutes one of the most important geometrical and mechanical features of the prosthesis.Several different implants are currently available but data are limited concerning the clinical results for some of these implants.AIM To report the short-term clinical and radiological results of a novel squared section,tapered design–with four conicity-short stem in total hip replacement.METHODS This is a retrospective study of a prospectively collected data using of MINIMA?short stem in 61 consecutive patients with at least 1 year follow-up.The collected data included patients’demographics,type of arthritis,bone morphology,perioperative data,clinical results using Harris Hip Score,EuroQol(EQ-5D),pain score and satisfaction rate,complications and radiological results.RESULTS Total 61 patients were included in our study with a mean age of 56 years of age(range 25-73 years).The majority of them(68.6%)were women,thirty seven patients(56.9%)were less than 60 years of age and almost half of patients(45.1%)suffered from secondary osteoarthritis(hip dysplasia,osteonecrosis,etc.).The mean time of follow-up examination was 33.4 mo(2.8 years)with a range of 12-57 months(1-4.8 years).In 35 patients(56.9%)the follow-up examination was more than 3 years.No major complications such as revision,periprosthetic fracture,dislocation or infection were presented.Re-admission 90 d postoperatively or laterwas deemed unnecessary for any reason regarding the operation.Respectively,the mean pain score,mean Harris hip score,and mean EQ-5D were improved from 6.3,58.7 and 77.3 preoperatively to 0.1,95.1,and 79.8 postoperatively.The Satisfaction rate at the final follow-up was 9.9(SD 0.3,range 8.0-10.0).All stems were classified as stable bone ingrowth and no radiolucent lineswere revealed in any of the modified Gruens’zone at the postoperative Xrays.Stem subsidence was within acceptable limits and the incidence of distal cortical hypertrophy was relatively low.CONCLUSION The clinical and radiological results concerning the MINIMA?short stem are excellent according to this first report of this specific design of the short femoral stems.Because of the small number of cases and short-term follow-up of this study,a longer follow up time and more patients’enrollment is required.
文摘The restaurant is traditional industry of the third industry in our country. Since May 1 in this year, China＇s Restaurant Industry to implement ＂replace the business tax with value-added tax＂ policy and change to pay VAT. This paper analyzed the possible impact on restaurant industry after the＂ replace the business tax with value-added tax＂ based on the understanding of the tax theory of＂ replace the business tax with value-added tax＂ and the tax compliance in our country. At the same time, this paper used the statistical analysis of data on the investigation of 100 samples of the VAT cognitive degree on ＂replace the business tax with value-added tax＂, using principal component analysis method to analyze and evaluate factors on the awareness of the restaurant owner to ＂replace the business tax with value-added tax＂ tax policy. After multiple comparison made on the sample data, this paper summarized and analyzed the countermeasures of improving the pushing effect in restaurant industry ＂replace the business tax with VAT ＂.
文摘We consider a replacement policy for a multiple-component cold-standbysystem, and after we analyze this policy, we want to get the mean total cost rate and the preventivepolicy to make it the lowest. In this system, the failure rate of the component in operation isconstant, and the inspection will control all the processes of the operation. The system isinspected at random points over time to determine whether it is to be replaced. During the process,the replacement decision is based on the number of failed components at the time of inspection.
