Failure of a stored system can only be detected after inspection and its reliability can be resumed by replacement of failed components. A maintenance policy of combining periodic inspection and preventive replacement...Failure of a stored system can only be detected after inspection and its reliability can be resumed by replacement of failed components. A maintenance policy of combining periodic inspection and preventive replacement is proposed to improve its availability. To coordinate component replacement and spare provision,an ordering policy of (0,1) is considered jointly. Thus,the joint maintenance policy contains inspection,replacement and spare provision. A programming model based on the joint maintenance policy is established,whose objective function is average expected cost,containing maintenance cost and inventory cost,and the constraint is system availability. Applying renewal theorem,the performance indexes are deduced under the condition that the stored system obeys the common life distribution. Numerical examples are given for a stored system with two different units,where unit 1 probability degrades with time and unit 2 probability degrades at each test. The effect of reliability parameters on the policies is discussed. The results indicate that the joint policy is very close to the independent policy.展开更多
In this paper, the optimization of micro-cogeneration (μ-CHP) system sizing for convenience stores in Thailand is conducted under the present condition of fuel prices and tariff rates. The assessment of (μ-CHP) syst...In this paper, the optimization of micro-cogeneration (μ-CHP) system sizing for convenience stores in Thailand is conducted under the present condition of fuel prices and tariff rates. The assessment of (μ-CHP) system performance is analyzed by using Primary Energy Saving (PES) Ratio for evaluating the energy performance. Also, the Annual Cost Saving Ratio (CSR) and Payback Period (PBP) are used for evaluating the economic performance of μ-CHP system. The analysis results show the optimal size of μ-CHP system under possible conditions including the operating schedule and system’s efficiency were conducted.展开更多
存储过程和触发器是数据库中的重要编程对象,在系统设计中可以提升数据库的性能。触发器是一种特殊的存储过程,主要用于实现比约束更复杂的功能,维护数据的完整性。文章利用SQL Server 2019数据库管理工具,以商超管理系统为例,研究存储...存储过程和触发器是数据库中的重要编程对象,在系统设计中可以提升数据库的性能。触发器是一种特殊的存储过程,主要用于实现比约束更复杂的功能,维护数据的完整性。文章利用SQL Server 2019数据库管理工具,以商超管理系统为例,研究存储过程和触发器在该系统中的应用,并结合实际案例,给出了存储过程和触发器在解决具体业务问题中的实现方法。展开更多
基金Sponsored by the National Nature Science Foundation of China (60674085)
文摘Failure of a stored system can only be detected after inspection and its reliability can be resumed by replacement of failed components. A maintenance policy of combining periodic inspection and preventive replacement is proposed to improve its availability. To coordinate component replacement and spare provision,an ordering policy of (0,1) is considered jointly. Thus,the joint maintenance policy contains inspection,replacement and spare provision. A programming model based on the joint maintenance policy is established,whose objective function is average expected cost,containing maintenance cost and inventory cost,and the constraint is system availability. Applying renewal theorem,the performance indexes are deduced under the condition that the stored system obeys the common life distribution. Numerical examples are given for a stored system with two different units,where unit 1 probability degrades with time and unit 2 probability degrades at each test. The effect of reliability parameters on the policies is discussed. The results indicate that the joint policy is very close to the independent policy.
文摘In this paper, the optimization of micro-cogeneration (μ-CHP) system sizing for convenience stores in Thailand is conducted under the present condition of fuel prices and tariff rates. The assessment of (μ-CHP) system performance is analyzed by using Primary Energy Saving (PES) Ratio for evaluating the energy performance. Also, the Annual Cost Saving Ratio (CSR) and Payback Period (PBP) are used for evaluating the economic performance of μ-CHP system. The analysis results show the optimal size of μ-CHP system under possible conditions including the operating schedule and system’s efficiency were conducted.
文摘存储过程和触发器是数据库中的重要编程对象,在系统设计中可以提升数据库的性能。触发器是一种特殊的存储过程,主要用于实现比约束更复杂的功能,维护数据的完整性。文章利用SQL Server 2019数据库管理工具,以商超管理系统为例,研究存储过程和触发器在该系统中的应用,并结合实际案例,给出了存储过程和触发器在解决具体业务问题中的实现方法。
