Aiming to efficiently support theLocator/Identifier Separation Protocol(LISP),in this paper,we present an enhanced pointerbased DHT mapping system:LISP-PCHORD.The system creates a pointer space to build ontop of stand...Aiming to efficiently support theLocator/Identifier Separation Protocol(LISP),in this paper,we present an enhanced pointerbased DHT mapping system:LISP-PCHORD.The system creates a pointer space to build ontop of standard DHTs.Mappings within thepointer space are(Endpoint Identifiers(EID),pointers) where the pointer is the address ofthe root node(the physical node that stores themappings) of the corresponding(EID,RoutingLocators(RLOCs)) mappings.In addition toenabling architectural qualities such as scalability and reliability,the proposed LISP-PCHORDcan copy with flat EIDs such as self-certifyingEIDs.The performance of the mapping systemplays a key role in LISP;however,DHT-basedapproaches for LISP seldom consider the mismatch problem that heavily damages the system performance in terms of lookup latency.In order to mitigate the mismatch problem andachieve optimal performance,we propose anoptimization design method that seeks an optimal matching relationship between P-nodes(nodes within the pointer space) and the physical nodes on the basis of the given lookuptraffic matrix.In order to find the optimal matching relationship,we provide two solutions:a linear programming method and a geneticalgorithm.Finally,we evaluate the performance of the proposed scheme and compare itwith that of LISP-DHT.展开更多
Although ge ne tic algorithm has become very famous with its global searching, parallel computi ng, better robustness, and not needing differential information during evolution .However, it also has some demerits, suc...Although ge ne tic algorithm has become very famous with its global searching, parallel computi ng, better robustness, and not needing differential information during evolution .However, it also has some demerits, such as slow convergence speed. In this pap er, based on several general theorems, an improved genetic algorithm using varia nt chromosome length and probability of crossover and mutation is proposed, and its main idea is as follows:at the beginning of evolution, our solution with sho rter length chromosome and higher probability of crossover and mutation; and at the vicinity of global optimum, with longer length chromosome and lower probabil ity of crossover and mutation. Finally, testing with some critical functions sho ws that our solution can improve the convergence speed of genetic algorithm sign ificantly, its comprehensive performance is better than that of the genetic algo rithm which only reserves the best individual.展开更多
The overhead in iSCSI subsystems is analyzed through the model of iSCSI reading and writing requests. An analytic model of iSCSI subsystem overhead is developed. According to the analytic model, the overhead of iSCSI ...The overhead in iSCSI subsystems is analyzed through the model of iSCSI reading and writing requests. An analytic model of iSCSI subsystem overhead is developed. According to the analytic model, the overhead of iSCSI subsystems is measured, which reveals that the main overhead is caused by protocol processing as well as kernel functions for fair allocation of system resources. Several methods have been proposed to optimize iSCSI subsystems, such as small I/O requests adherent that can be merged into a large I/O request. Checksum is found to be a time consuming work and may not be always necessary for applications.展开更多
The desulphurization experiment of oil-soluble oxidant tert-amyl hydroperoxide with dibenzothiophene dissolved in decalin as model-oil was researched. Characterisation on oxidation product was made, and dibenzothiophe...The desulphurization experiment of oil-soluble oxidant tert-amyl hydroperoxide with dibenzothiophene dissolved in decalin as model-oil was researched. Characterisation on oxidation product was made, and dibenzothiophene removal rate was computed. The influence factors of the oxidative reaction regent amount and the condtions of reaction temperature and reaction time were optimized and compared. The best reaction condition was reaction temperature 90℃, reaction time 3 h, ratio of oxygen to sulfur 4：1, catalyst amount 0.12 g. Dibenzothiophene removal rate reached 97% in this reaction condition.展开更多
Y2000-62566-167 0113637基于集电极外延层工程的扩频通信系统性能最优化=Spread spectrum communication system performance op-timization based on collector epilayer engineering [会,英]/Mahmoudi, R. & Tauritz, J. L.//200...Y2000-62566-167 0113637基于集电极外延层工程的扩频通信系统性能最优化=Spread spectrum communication system performance op-timization based on collector epilayer engineering [会,英]/Mahmoudi, R. & Tauritz, J. L.//2000 IEEETopical Meeting on Silicon Monolithic Integrated Circuitsin RF Systems, Digest of Papers. —167～172(EC)展开更多
基金supported by the National Key Basic Research Program of China(973Program) under Grant No.2007CB307100the National Natural Science Foundation of China under Grant No.61001084
文摘Aiming to efficiently support theLocator/Identifier Separation Protocol(LISP),in this paper,we present an enhanced pointerbased DHT mapping system:LISP-PCHORD.The system creates a pointer space to build ontop of standard DHTs.Mappings within thepointer space are(Endpoint Identifiers(EID),pointers) where the pointer is the address ofthe root node(the physical node that stores themappings) of the corresponding(EID,RoutingLocators(RLOCs)) mappings.In addition toenabling architectural qualities such as scalability and reliability,the proposed LISP-PCHORDcan copy with flat EIDs such as self-certifyingEIDs.The performance of the mapping systemplays a key role in LISP;however,DHT-basedapproaches for LISP seldom consider the mismatch problem that heavily damages the system performance in terms of lookup latency.In order to mitigate the mismatch problem andachieve optimal performance,we propose anoptimization design method that seeks an optimal matching relationship between P-nodes(nodes within the pointer space) and the physical nodes on the basis of the given lookuptraffic matrix.In order to find the optimal matching relationship,we provide two solutions:a linear programming method and a geneticalgorithm.Finally,we evaluate the performance of the proposed scheme and compare itwith that of LISP-DHT.
文摘Although ge ne tic algorithm has become very famous with its global searching, parallel computi ng, better robustness, and not needing differential information during evolution .However, it also has some demerits, such as slow convergence speed. In this pap er, based on several general theorems, an improved genetic algorithm using varia nt chromosome length and probability of crossover and mutation is proposed, and its main idea is as follows:at the beginning of evolution, our solution with sho rter length chromosome and higher probability of crossover and mutation; and at the vicinity of global optimum, with longer length chromosome and lower probabil ity of crossover and mutation. Finally, testing with some critical functions sho ws that our solution can improve the convergence speed of genetic algorithm sign ificantly, its comprehensive performance is better than that of the genetic algo rithm which only reserves the best individual.
基金Funded by National Network and Security Continuous Developing Plan (2004 Research 1-917-021)
文摘The overhead in iSCSI subsystems is analyzed through the model of iSCSI reading and writing requests. An analytic model of iSCSI subsystem overhead is developed. According to the analytic model, the overhead of iSCSI subsystems is measured, which reveals that the main overhead is caused by protocol processing as well as kernel functions for fair allocation of system resources. Several methods have been proposed to optimize iSCSI subsystems, such as small I/O requests adherent that can be merged into a large I/O request. Checksum is found to be a time consuming work and may not be always necessary for applications.
文摘The desulphurization experiment of oil-soluble oxidant tert-amyl hydroperoxide with dibenzothiophene dissolved in decalin as model-oil was researched. Characterisation on oxidation product was made, and dibenzothiophene removal rate was computed. The influence factors of the oxidative reaction regent amount and the condtions of reaction temperature and reaction time were optimized and compared. The best reaction condition was reaction temperature 90℃, reaction time 3 h, ratio of oxygen to sulfur 4：1, catalyst amount 0.12 g. Dibenzothiophene removal rate reached 97% in this reaction condition.
文摘Y2000-62566-167 0113637基于集电极外延层工程的扩频通信系统性能最优化=Spread spectrum communication system performance op-timization based on collector epilayer engineering [会,英]/Mahmoudi, R. & Tauritz, J. L.//2000 IEEETopical Meeting on Silicon Monolithic Integrated Circuitsin RF Systems, Digest of Papers. —167～172(EC)
