例1:There are few__in the fridge.Let’s go and buy some peas,carrots and cab-bages. (2002河南) A.vegetables B.fruit C.meat D.eggs 丢分原因分析:本题考查名词的用法。从语法上看,few修饰复数可数名词,可排除选项B,C;从逻辑上...例1:There are few__in the fridge.Let’s go and buy some peas,carrots and cab-bages. (2002河南) A.vegetables B.fruit C.meat D.eggs 丢分原因分析:本题考查名词的用法。从语法上看,few修饰复数可数名词,可排除选项B,C;从逻辑上看,下句表示“我们去买些豌豆、胡萝卜和洋白菜吧。”peas,carrots and cabbages正是vegetables的具体形式,D被排除,故选A。展开更多
We investigate the approximating capability of Markov modulated Poisson processes (MMPP) for modeling multifractal Internet traffic. The choice of MMPP is motivated by its ability to capture the variability and correl...We investigate the approximating capability of Markov modulated Poisson processes (MMPP) for modeling multifractal Internet traffic. The choice of MMPP is motivated by its ability to capture the variability and correlation in moderate time scales while being analytically tractable. Important statistics of traffic burstiness are described and a customized moment-based fitting procedure of MMPP to traffic traces is presented. Our methodology of doing this is to examine whether the MMPP can be used to predict the performance of a queue to which MMPP sample paths and measured traffic traces are fed for comparison respectively, in addition to the goodness-of-fit test of MMPP. Numerical results and simulations show that the fitted MMPP can approximate multifractal traffic quite well, i.e. accurately predict the queueing performance.展开更多
The basic mobile IP protocol is simple but only suitable for wide area and low speed networks. In this paper, we propose a novel micro-mobile IP handoff scheme, that is the packet loss avoidance handoff scheme. By usi...The basic mobile IP protocol is simple but only suitable for wide area and low speed networks. In this paper, we propose a novel micro-mobile IP handoff scheme, that is the packet loss avoidance handoff scheme. By using an additional cache at the base station and distinguishing packets with packet IDs, the proposed scheme minimizes the number of lost packets during handoff. Network architecture and detailed handoff procedures are given. We also analyze the cache size at the base station, the associated network load with the handoff procedure, and the handoff delay. The scheme is investigated by computer simulations. Simulation results show that the proposed scheme is suitable for environments with fast mobility and frequent handoff.展开更多
In this paper, it is shown that： if λ1 ,……λs axe nonzero real numbers, not all of the same sign, such that A1/A2 is irrational, then for any real number η and ε 〉 0 the inequality ｜λ1x1^2 ＋ λ2x2^2＋ λ3x3^...In this paper, it is shown that： if λ1 ,……λs axe nonzero real numbers, not all of the same sign, such that A1/A2 is irrational, then for any real number η and ε 〉 0 the inequality ｜λ1x1^2 ＋ λ2x2^2＋ λ3x3^4＋ λsx3^4＋……λsx8^4 ＋η〈 ε has infinitely many solutions in positive integers x1,... ,xs.展开更多
In opportunistic networks, most existing buffer management policies including scheduling and passive dropping policies are mainly for routing protocols. In this paper, we proposed a Utility-based Buffer Management str...In opportunistic networks, most existing buffer management policies including scheduling and passive dropping policies are mainly for routing protocols. In this paper, we proposed a Utility-based Buffer Management strategy(UBM) for data dissemination in opportunistic networks. In UBM, we first design a method of computing the utility values of caching messages according to the interest of nodes and the delivery probability of messages, and then propose an overall buffer management policy based on the utility. UBM driven by receivers completely implements not only caching policies, passive and proactive dropping policies, but also scheduling policies of senders. Simulation results show that, compared with some classical dropping strategies, UBM can obtain higher delivery ratio and lower delay latency by using smaller network cost.展开更多
文摘例1:There are few__in the fridge.Let’s go and buy some peas,carrots and cab-bages. (2002河南) A.vegetables B.fruit C.meat D.eggs 丢分原因分析:本题考查名词的用法。从语法上看,few修饰复数可数名词,可排除选项B,C;从逻辑上看,下句表示“我们去买些豌豆、胡萝卜和洋白菜吧。”peas,carrots and cabbages正是vegetables的具体形式,D被排除,故选A。
文摘We investigate the approximating capability of Markov modulated Poisson processes (MMPP) for modeling multifractal Internet traffic. The choice of MMPP is motivated by its ability to capture the variability and correlation in moderate time scales while being analytically tractable. Important statistics of traffic burstiness are described and a customized moment-based fitting procedure of MMPP to traffic traces is presented. Our methodology of doing this is to examine whether the MMPP can be used to predict the performance of a queue to which MMPP sample paths and measured traffic traces are fed for comparison respectively, in addition to the goodness-of-fit test of MMPP. Numerical results and simulations show that the fitted MMPP can approximate multifractal traffic quite well, i.e. accurately predict the queueing performance.
文摘The basic mobile IP protocol is simple but only suitable for wide area and low speed networks. In this paper, we propose a novel micro-mobile IP handoff scheme, that is the packet loss avoidance handoff scheme. By using an additional cache at the base station and distinguishing packets with packet IDs, the proposed scheme minimizes the number of lost packets during handoff. Network architecture and detailed handoff procedures are given. We also analyze the cache size at the base station, the associated network load with the handoff procedure, and the handoff delay. The scheme is investigated by computer simulations. Simulation results show that the proposed scheme is suitable for environments with fast mobility and frequent handoff.
基金the National Natural Science Foundation of China(10671056)
文摘In this paper, it is shown that： if λ1 ,……λs axe nonzero real numbers, not all of the same sign, such that A1/A2 is irrational, then for any real number η and ε 〉 0 the inequality ｜λ1x1^2 ＋ λ2x2^2＋ λ3x3^4＋ λsx3^4＋……λsx8^4 ＋η〈 ε has infinitely many solutions in positive integers x1,... ,xs.
基金supported by the National Natural Science Fund of China under Grant No. 61472097the Education Ministry Doctoral Research Foundation of China (20132304110017)the International Exchange Program of Harbin Engineering University for Innovation-oriented Talents Cultivation
文摘In opportunistic networks, most existing buffer management policies including scheduling and passive dropping policies are mainly for routing protocols. In this paper, we proposed a Utility-based Buffer Management strategy(UBM) for data dissemination in opportunistic networks. In UBM, we first design a method of computing the utility values of caching messages according to the interest of nodes and the delivery probability of messages, and then propose an overall buffer management policy based on the utility. UBM driven by receivers completely implements not only caching policies, passive and proactive dropping policies, but also scheduling policies of senders. Simulation results show that, compared with some classical dropping strategies, UBM can obtain higher delivery ratio and lower delay latency by using smaller network cost.
