Accuracy allocation is crucial in the accuracy design of machining tools.Current accuracy allocation methods primarily focus on positional deviation,with little consideration for tool direction deviation.To address th...Accuracy allocation is crucial in the accuracy design of machining tools.Current accuracy allocation methods primarily focus on positional deviation,with little consideration for tool direction deviation.To address this issue,we propose a geometric error cost sensitivity-based accuracy allocation method for five-axis machine tools.A geometric error model consisting of 4l error components is constructed based on homogeneous transformation matrices.Volumetric points with positional and tool direction deviations are randomly sampled to evaluate the accuracy of the machine tool.The sensitivity of each error component at these sampling points is analyzed using the Sobol method.To balance the needs of geometric precision and manufacturing cost,a geometric error cost sensitivity function is developed to estimate the required cost.By allocating error components affecting tool direction deviation first and the remaining components second,this allocation scheme ensures that both deviations meet the requirements.We also perform numerical simulation of a BC-type(B-axis and C-axis type)five-axis machine tool to validate the method.The results show that the new allocation scheme reduces the total geometric error cost by 27.8%compared to a uniform allocation scheme,and yields the same positional and tool direction machining accuracies.展开更多
In a real estate project, the estimated cost of construction and the revenues generally represent together the most important values of its feasibility study. When a decision of undertaking a project is made, often th...In a real estate project, the estimated cost of construction and the revenues generally represent together the most important values of its feasibility study. When a decision of undertaking a project is made, often there are few definitions of what is about to be constructed, and frequently not enough to ensure the accuracy of the estimated costs. Considering a global tendency on reducing margins of return over the real estate markets, slight variations of the construction cost can jeopardize the success of the whole real estate enterprise and even the financial stability of the builder or of the developer. This article aims at presenting a method of estimating the building construction costs applicable at the stage of feasibility studies, being able to provide acceptable errors.展开更多
Medical errors are reported with increased frequency both in Europe and in the United States of America and measures are put in place to deal with the problem. In Greece, more and more patients think that it is likely...Medical errors are reported with increased frequency both in Europe and in the United States of America and measures are put in place to deal with the problem. In Greece, more and more patients think that it is likely to experience a medical error during health care delivery and the organizations they can turn to if this happens are hardly enough and with meagre response. The consequences of medical errors are multiple and complex with significant financial implications. Nowadays there is an urgent need to resolve problems that refer to cost containment in the Greek Health System. Some research findings from the review of 128 compensations awarded by civil courts for the years 2000 to 2009 for medical errors in Greece are quite interesting. The mean compensation amounted to €292,613 representing 35.41% of claimed compensation. Only a small proportion of medical errors gain publicity as the majority of claims get settled out of court, covered by the insurance policy or the hospitals. The burden of the obvious and hidden cost affects not only the patient, his family and the hospital but also the whole of the society. This comes from our estimation that the level of compensation awarded by the civil courts for medical errors is remarkable high. Unfortunately only some estimates of the cost are possible due to the lack of statistical data. The creation of an independent oversight body for the review of medical errors and complaints nationwide as well as the modernization of the hospitals’ monitoring systems is necessary in order to handle the medical error phenomenon. Above all, cooperation and trust between patients, health care professionals, hospital managers, medical boards and the government are essential to get to the root of the problem.展开更多
基金supported by the Key R&D Program of Zhejiang Province(Nos.2023C01166 and 2024SJCZX0046)the Zhejiang Provincial Natural Science Foundation of China(Nos.LDT23E05013E05 and LD24E050009)the Natural Science Foundation of Ningbo(No.2021J150),China.
文摘Accuracy allocation is crucial in the accuracy design of machining tools.Current accuracy allocation methods primarily focus on positional deviation,with little consideration for tool direction deviation.To address this issue,we propose a geometric error cost sensitivity-based accuracy allocation method for five-axis machine tools.A geometric error model consisting of 4l error components is constructed based on homogeneous transformation matrices.Volumetric points with positional and tool direction deviations are randomly sampled to evaluate the accuracy of the machine tool.The sensitivity of each error component at these sampling points is analyzed using the Sobol method.To balance the needs of geometric precision and manufacturing cost,a geometric error cost sensitivity function is developed to estimate the required cost.By allocating error components affecting tool direction deviation first and the remaining components second,this allocation scheme ensures that both deviations meet the requirements.We also perform numerical simulation of a BC-type(B-axis and C-axis type)five-axis machine tool to validate the method.The results show that the new allocation scheme reduces the total geometric error cost by 27.8%compared to a uniform allocation scheme,and yields the same positional and tool direction machining accuracies.
文摘In a real estate project, the estimated cost of construction and the revenues generally represent together the most important values of its feasibility study. When a decision of undertaking a project is made, often there are few definitions of what is about to be constructed, and frequently not enough to ensure the accuracy of the estimated costs. Considering a global tendency on reducing margins of return over the real estate markets, slight variations of the construction cost can jeopardize the success of the whole real estate enterprise and even the financial stability of the builder or of the developer. This article aims at presenting a method of estimating the building construction costs applicable at the stage of feasibility studies, being able to provide acceptable errors.
文摘Medical errors are reported with increased frequency both in Europe and in the United States of America and measures are put in place to deal with the problem. In Greece, more and more patients think that it is likely to experience a medical error during health care delivery and the organizations they can turn to if this happens are hardly enough and with meagre response. The consequences of medical errors are multiple and complex with significant financial implications. Nowadays there is an urgent need to resolve problems that refer to cost containment in the Greek Health System. Some research findings from the review of 128 compensations awarded by civil courts for the years 2000 to 2009 for medical errors in Greece are quite interesting. The mean compensation amounted to €292,613 representing 35.41% of claimed compensation. Only a small proportion of medical errors gain publicity as the majority of claims get settled out of court, covered by the insurance policy or the hospitals. The burden of the obvious and hidden cost affects not only the patient, his family and the hospital but also the whole of the society. This comes from our estimation that the level of compensation awarded by the civil courts for medical errors is remarkable high. Unfortunately only some estimates of the cost are possible due to the lack of statistical data. The creation of an independent oversight body for the review of medical errors and complaints nationwide as well as the modernization of the hospitals’ monitoring systems is necessary in order to handle the medical error phenomenon. Above all, cooperation and trust between patients, health care professionals, hospital managers, medical boards and the government are essential to get to the root of the problem.
