Load shedding is a significant problem in rural areas.During a power outage,the cabin temperature of a refrigerator increases owing to the heat gain.In practice,a door should be opened to load and unload refrigerator ...Load shedding is a significant problem in rural areas.During a power outage,the cabin temperature of a refrigerator increases owing to the heat gain.In practice,a door should be opened to load and unload refrigerator products,particularly when the power failure period is longer.The use of a phase-change material(PCM)in the refrigerator cabin restricts the increase in temperature and provides a backup time that reduces energy con-sumption.Door-opening tests are essential during a power cut-off time to investigate the reduction in backup time owing to door openings.This article presents an experimental investigation on the influence of PCM masses of potassium chloride,sodium chloride,and sodium fluoride dissolved in water on the backup time and equivalent energy consumption of a domestic refrigerator for closed and open doors according to the standards IS 1476 and IEC 62552:2015.The backup time of closed-door tests was significantly increased by the PCM for all masses,i.e.,between 15 and 200 min in absolute terms and between 14%and 182%in relative terms.The backup time for the closed-door tests was 1.8-1.03 times longer than that for the door-opening tests.The backup time of door-opening tests decreased significantly owing to heat entering the cabin for all masses,i.e.,between 50 and 10 min in absolute terms and between 45.45%and 3.23%in relative terms.The equivalent energy consumption of a refrigerator decreased with an increase in PCM mass.In the door-opening tests,the equivalent energy consumption increased owing to door opening.The equivalent energy consumption for the door-opening tests was 1.12-1.02 times larger than that for the closed-door tests.展开更多
In the context of real-time fault-tolerant scheduling in multiprocessor systems, Primary-backup scheme plays an important role. A backup copy is always preferred to be executed as passive backup copy whenever possible...In the context of real-time fault-tolerant scheduling in multiprocessor systems, Primary-backup scheme plays an important role. A backup copy is always preferred to be executed as passive backup copy whenever possible because it can take the advantages of backup copy de-allocation technique and overloading technique to improve schedulability. In this paper, we propose a novel efficient fault-tolerant ratemonotonic best-fit algorithm efficient fault-tolerant rate-monotonic best-fit （ERMBF） based on multiprocessors systems to enhance the schedulability. Unlike existing scheduling algorithms that start scheduling tasks with only one processor. ERMBF pre-allocates a certain amount of processors before starting scheduling tasks, which enlarge the searching spaces for tasks. Besides, when a new processor is allocated, we reassign the task copies that have already been assigned to the existing processors in order to find a superior tasks assignment configuration. These two strategies are all aiming at making as many backup copies as possible to be executed as passive status. As a result, ERMBF can use fewer processors to schedule a set of tasks without losing real-time and fault-tolerant capabilities of the system. Simulation results reveal that ERMBF significantly improves the schedulability over existing, comparable algorithms in literature.展开更多
The given article deals with the development of analytical model of request service process by multichannel technical system with unreliable, repaired and reconfigured service facilities. It is assumed that the system...The given article deals with the development of analytical model of request service process by multichannel technical system with unreliable, repaired and reconfigured service facilities. It is assumed that the system is functioning in service mode of random length random request flows. The system considers the existence of time redundancy for afterservice of calls, the service of which is interrupted with refusal, non-depreciating the performed part of the task. Special probability functions are introduced which on the basis of probability reasoning allow to make the systems of integral equations describing the dynamics of request service process.展开更多
针对电力系统变电站直流系统,在变电站蓄电池核对容量、直流电源技术改造中及事故处理中,应用并联技术配磷酸铁锂电池在电力后备电源替代传统的阀控密闭铅酸电池或镉镍作为后备电池。采用已有的新技术,并联技术配磷酸铁锂电池方案的设计...针对电力系统变电站直流系统,在变电站蓄电池核对容量、直流电源技术改造中及事故处理中,应用并联技术配磷酸铁锂电池在电力后备电源替代传统的阀控密闭铅酸电池或镉镍作为后备电池。采用已有的新技术,并联技术配磷酸铁锂电池方案的设计,具有便携可移动、环保无污染、备用蓄电池维护量少、安全稳定、接线简单等特点,并进一步论证计算适合在220 k V及以下等级的变电站应用的安全性。展开更多
文摘Load shedding is a significant problem in rural areas.During a power outage,the cabin temperature of a refrigerator increases owing to the heat gain.In practice,a door should be opened to load and unload refrigerator products,particularly when the power failure period is longer.The use of a phase-change material(PCM)in the refrigerator cabin restricts the increase in temperature and provides a backup time that reduces energy con-sumption.Door-opening tests are essential during a power cut-off time to investigate the reduction in backup time owing to door openings.This article presents an experimental investigation on the influence of PCM masses of potassium chloride,sodium chloride,and sodium fluoride dissolved in water on the backup time and equivalent energy consumption of a domestic refrigerator for closed and open doors according to the standards IS 1476 and IEC 62552:2015.The backup time of closed-door tests was significantly increased by the PCM for all masses,i.e.,between 15 and 200 min in absolute terms and between 14%and 182%in relative terms.The backup time for the closed-door tests was 1.8-1.03 times longer than that for the door-opening tests.The backup time of door-opening tests decreased significantly owing to heat entering the cabin for all masses,i.e.,between 50 and 10 min in absolute terms and between 45.45%and 3.23%in relative terms.The equivalent energy consumption of a refrigerator decreased with an increase in PCM mass.In the door-opening tests,the equivalent energy consumption increased owing to door opening.The equivalent energy consumption for the door-opening tests was 1.12-1.02 times larger than that for the closed-door tests.
基金Supported by the National Basic Reseach Program of China (973 Program 2004 CB318200)
文摘In the context of real-time fault-tolerant scheduling in multiprocessor systems, Primary-backup scheme plays an important role. A backup copy is always preferred to be executed as passive backup copy whenever possible because it can take the advantages of backup copy de-allocation technique and overloading technique to improve schedulability. In this paper, we propose a novel efficient fault-tolerant ratemonotonic best-fit algorithm efficient fault-tolerant rate-monotonic best-fit （ERMBF） based on multiprocessors systems to enhance the schedulability. Unlike existing scheduling algorithms that start scheduling tasks with only one processor. ERMBF pre-allocates a certain amount of processors before starting scheduling tasks, which enlarge the searching spaces for tasks. Besides, when a new processor is allocated, we reassign the task copies that have already been assigned to the existing processors in order to find a superior tasks assignment configuration. These two strategies are all aiming at making as many backup copies as possible to be executed as passive status. As a result, ERMBF can use fewer processors to schedule a set of tasks without losing real-time and fault-tolerant capabilities of the system. Simulation results reveal that ERMBF significantly improves the schedulability over existing, comparable algorithms in literature.
文摘The given article deals with the development of analytical model of request service process by multichannel technical system with unreliable, repaired and reconfigured service facilities. It is assumed that the system is functioning in service mode of random length random request flows. The system considers the existence of time redundancy for afterservice of calls, the service of which is interrupted with refusal, non-depreciating the performed part of the task. Special probability functions are introduced which on the basis of probability reasoning allow to make the systems of integral equations describing the dynamics of request service process.
文摘针对电力系统变电站直流系统,在变电站蓄电池核对容量、直流电源技术改造中及事故处理中,应用并联技术配磷酸铁锂电池在电力后备电源替代传统的阀控密闭铅酸电池或镉镍作为后备电池。采用已有的新技术,并联技术配磷酸铁锂电池方案的设计,具有便携可移动、环保无污染、备用蓄电池维护量少、安全稳定、接线简单等特点,并进一步论证计算适合在220 k V及以下等级的变电站应用的安全性。
