The ＂torque rich＂ is known as a phenomenon that makes reduction of ship speed, overload for main engine and higher fuel consumption of ship, even can cause some major problems for a ship propulsion system. In Vietna...The ＂torque rich＂ is known as a phenomenon that makes reduction of ship speed, overload for main engine and higher fuel consumption of ship, even can cause some major problems for a ship propulsion system. In Vietnam, according to investigated results, almost ships of country merchant fleet are facing with ship speed decrease, fuel consumption increase due to the torque rich, consequently the average ship operation cost is increasing from 15% to 25%, even higher in some cases and the environment is badly impacted. To comply with the international requirements and national legislation regarding to ＂using efficiently energy and environment protection＂, Vietnamese shipping companies must combat with the torque rich problem as crucial reason making downgrade in ship operation. The article shows a potential method to reduce the torque rich phenomena by modifying propeller which has been successfully applied for a real ship in Vietnam.展开更多
Data stream management system (DSMS) provides convenient solutions to the problem of processing continuous queries on data streams.Previous approaches for scheduling these queries and their operators assume that each ...Data stream management system (DSMS) provides convenient solutions to the problem of processing continuous queries on data streams.Previous approaches for scheduling these queries and their operators assume that each operator runs in separate thread or all operators combine in one query plan and run in a single thread.Both approaches suffer from severe drawbacks concerning the thread overhead and the stalls due to expensive operators.To overcome these drawbacks,a novel approach called clustered operators scheduling (COS) is proposed that adaptively clusters operators of the query plan into a number of groups based on their selectivity and computing cost using S-mean clustering.Experimental evaluation is provided to demonstrate the potential benefits of COS scheduling over the other scheduling strategies.COS can provide adaptive,flexible,reliable,scalable and robust design for continuous query processor.展开更多
文摘The ＂torque rich＂ is known as a phenomenon that makes reduction of ship speed, overload for main engine and higher fuel consumption of ship, even can cause some major problems for a ship propulsion system. In Vietnam, according to investigated results, almost ships of country merchant fleet are facing with ship speed decrease, fuel consumption increase due to the torque rich, consequently the average ship operation cost is increasing from 15% to 25%, even higher in some cases and the environment is badly impacted. To comply with the international requirements and national legislation regarding to ＂using efficiently energy and environment protection＂, Vietnamese shipping companies must combat with the torque rich problem as crucial reason making downgrade in ship operation. The article shows a potential method to reduce the torque rich phenomena by modifying propeller which has been successfully applied for a real ship in Vietnam.
基金Project(50275150) supported by the National Natural Science Foundation of ChinaProject(20040533035) supported by the National Research Foundation for the Doctoral Program of Higher Education of China
文摘Data stream management system (DSMS) provides convenient solutions to the problem of processing continuous queries on data streams.Previous approaches for scheduling these queries and their operators assume that each operator runs in separate thread or all operators combine in one query plan and run in a single thread.Both approaches suffer from severe drawbacks concerning the thread overhead and the stalls due to expensive operators.To overcome these drawbacks,a novel approach called clustered operators scheduling (COS) is proposed that adaptively clusters operators of the query plan into a number of groups based on their selectivity and computing cost using S-mean clustering.Experimental evaluation is provided to demonstrate the potential benefits of COS scheduling over the other scheduling strategies.COS can provide adaptive,flexible,reliable,scalable and robust design for continuous query processor.
