针对按需距离矢量(ad hoc on-demand distance vector,AODV)路由协议在车载自组织网络(vehicle ad hoc network,VANET)中路由发现过程存在盲目广播和路径易断裂问题,提出了自适应邻节点的概率性广播策略。在请求包接收过程,根据请求包...针对按需距离矢量(ad hoc on-demand distance vector,AODV)路由协议在车载自组织网络(vehicle ad hoc network,VANET)中路由发现过程存在盲目广播和路径易断裂问题,提出了自适应邻节点的概率性广播策略。在请求包接收过程,根据请求包中引入的地理位置信息计算距离,减少边缘节点参与路由建立;在重播过程中,从路边基础设施获取区域内密度信息,各节点根据邻节点数量和区域内密度信息选择不同的广播概率。仿真结果表明,自适应邻节点的概率性广播策略减少了盲目广播,降低了路由负担、数据到达率得到提高。展开更多
Taking the time varying nature of wireless channels into account, two user selection schemes with lower complexity are developed for multiple-input multiple-output broadcast （MIMO BC）systems. According to the relati...Taking the time varying nature of wireless channels into account, two user selection schemes with lower complexity are developed for multiple-input multiple-output broadcast （MIMO BC）systems. According to the relationship between coherence time and Doppler frequency, an information frame is divided into several segments. At the beginning of each segment, the user selection is carded out with the greedy selection algorithm. In the simplified user selection algorithms employing the temporal correlation （SUSTC）, the selection results are applied for all the remaining slots in each segment. But in the improved simplified user selection algorithms employing the temporal correlation（ISUSTC）, at the remaining slots, users are kept with favorable channel conditions selected at the previous slot, and other users are updated from the candidate pool to communicate simultaneously. Simulations show that compared with the greedy user selection method, the proposed algorithms can reduce the selection complexity with a little sum capacity loss.展开更多
A direct conversion CMOS DVB-S front-end employs a T-configuration variable attenuator,a single-to- differential low noise amplifier, and a low noise mixer. By innovative use of the attenuator, the linearity handling ...A direct conversion CMOS DVB-S front-end employs a T-configuration variable attenuator,a single-to- differential low noise amplifier, and a low noise mixer. By innovative use of the attenuator, the linearity handling ability of the system is dramatically improved. The system is designed and fabricated in SMIC 0.18 μm RF CMOS technology. The measurement data show that the front-end provides a total of more than 30rib dynamic range and a noise figure of 5dB in the wide frequency signal band. The prototype front-end consumes only 10mA and achieves an IIP3 of ＋ 20dBm.展开更多
In Bangladesh, more than a dozen of private TV channels are operating and about 10 new channels are waiting with green signal for transmission. Bangladesh Television （BTV）, the only government owned and administered...In Bangladesh, more than a dozen of private TV channels are operating and about 10 new channels are waiting with green signal for transmission. Bangladesh Television （BTV）, the only government owned and administered, and known as structurally a biased institution serves the audience the public service information most. At the same time it serves purposes of incumbent government. Public information （PI） broadcast means broadcasting towards public welfare which may bring about change in the betterment of life and work of people. Its main focus would be on information, education, and motivation values rather than entertainment. In case of information, dissemination, and documentation, all private TV channels in Bangladesh serve more entertainment and less public service information, whereas, BTV＇s focus is evident on more PI. The owners and operators of private channels think first of their business profit as well as pressure from government and political parties. During formulating planning and strategies or building program content, they become cautious as they fear that the government become angry and shut down the channel.展开更多
To adjust the variance of source rate in linear broadcast networks, global encoding kernels should have corresponding dimensions to instruct the decoding process. The algorithm of constructing such global encoding ker...To adjust the variance of source rate in linear broadcast networks, global encoding kernels should have corresponding dimensions to instruct the decoding process. The algorithm of constructing such global encoding kernels is to adjust heterogeneous network to possible link failures. Linear algebra, graph theory and group theory are applied to construct one series of global encoding kernels which are applicable to all source rates. The effectiveness and existence of such global encoding kernels are proved. Based on 2 information flow, the algorithm of construction is explicitly given within polynomial time O（｜E｜ ｜T｜.ω^2max）, and the memory complexity of algorithm is O（｜E｜）. Both time and memory complexity of this algorithm proposed can be O（ωmax） less than those of algorithms in related works.展开更多
To enhance the robustness of a proxy multi-signature scheme and improve its efficiency, a novel proxy signature paradigm is proposed referred to as In this paradigm, multiple proxy signer candidates identity-based pro...To enhance the robustness of a proxy multi-signature scheme and improve its efficiency, a novel proxy signature paradigm is proposed referred to as In this paradigm, multiple proxy signer candidates identity-based proxy multi-signature （IBPMS）. are employed to play a role of the single proxy signer in the existing model. A provably secure IBPMS scheme is presented which requires only one round broadcast operation. Performance analysis demonstrates that the new scheme outperforms the existing multi-signature schemes in robustness and communication. These properties are rendered to our IBPMS scheme as a more practical solution to secure e-transaction delegation applications of proxy signatures.展开更多
The problem of maintaining data consistency in mobile broadcast environments is researched. Quasi serializability is formally defined and analyzed at first. It was shown that quasi serializability is less stringent th...The problem of maintaining data consistency in mobile broadcast environments is researched. Quasi serializability is formally defined and analyzed at first. It was shown that quasi serializability is less stringent than serializability when database consistency is maintained for transactions. Then, corresponding concurrency control protocol that supports both update transactions and read-only transactions is outlined for mobile broadcast environments. Finally, the simulation results confirmed that the proposed protocol could improve the response time significantly.展开更多
In order to reduce broadcast storms, improve network security, virtual LAN technology has been widely used in LAN planning. But in many networks, it was be required that computers in different VLAN （Virtual Local Are...In order to reduce broadcast storms, improve network security, virtual LAN technology has been widely used in LAN planning. But in many networks, it was be required that computers in different VLAN （Virtual Local Area Network） could be communicated. This article mainly introduced the VLAN classification method inter-VLAN data communication technology, and explained in detail with two simple examples the concrete configure method of the communication between the same cross-switch VLAN traffic and inter-VLAN.展开更多
Objective： To analyze the epidemiological characteristics of sexually transmitted infections （STIs） in Guangzhou from 2000 to 2003, in order to provide scientific evidence for control and prevention efforts. Method...Objective： To analyze the epidemiological characteristics of sexually transmitted infections （STIs） in Guangzhou from 2000 to 2003, in order to provide scientific evidence for control and prevention efforts. Methods： STI reports and demographic data in Guangzhou from 2000 to 2003 were collected and analyzed using the National STD Computer Management Software. Results： The incidence rate of total STIs decreased.The incidence of syphilis, gonorrhea and condyloma acuminata decreased yearly from 41.71/100,000,70.13/100,000 and 83.02/100,000 in 2000 to 32.36/100,000,54.35/100,000 and 67.03/100,000 in 2003, respectively.The incidence of HIV/AIDS increased yearly.Nongonococcal urethritis （cervicitis） was the most prevalent STI. Conclusions： Incidence of STIs in Guangzhou is decreasing overall, but the incidence of HIV/AIDS is increasing and there is a change in the pattern of STI epidemics. Efforts should be made to keep the epidemic under control.展开更多
Such an extremely difficult issue as cultural diversity is confronted by the existence and evolution of enterprises with the rapid development of global economy of the present. If the establishment is to boost competi...Such an extremely difficult issue as cultural diversity is confronted by the existence and evolution of enterprises with the rapid development of global economy of the present. If the establishment is to boost competitiveness, it must have a quite good knowledge of target market so as to formulate some efficient strategies of broadcasting in its management, and the best way to resolve such problem is to eliminate cultural barriers with the adoption of the transmission of cross-cultural advertisements. This thesis shall research cultural diversities between eastern nations and western ones, and explore the effect the diversities have upon cross-cultural transmission, thus to propose an approach of eliminating cultural isolation with the adoption of effective techniques and manners of the transmission of cross-cultural advertisements.展开更多
文摘针对按需距离矢量(ad hoc on-demand distance vector,AODV)路由协议在车载自组织网络(vehicle ad hoc network,VANET)中路由发现过程存在盲目广播和路径易断裂问题,提出了自适应邻节点的概率性广播策略。在请求包接收过程,根据请求包中引入的地理位置信息计算距离,减少边缘节点参与路由建立;在重播过程中,从路边基础设施获取区域内密度信息,各节点根据邻节点数量和区域内密度信息选择不同的广播概率。仿真结果表明,自适应邻节点的概率性广播策略减少了盲目广播,降低了路由负担、数据到达率得到提高。
基金The National High Technology Research and Develop-ment Program of China(863 Program)(No.2006AA01Z268)the NationalNatural Science Foundation of China(No.60496311).
文摘Taking the time varying nature of wireless channels into account, two user selection schemes with lower complexity are developed for multiple-input multiple-output broadcast （MIMO BC）systems. According to the relationship between coherence time and Doppler frequency, an information frame is divided into several segments. At the beginning of each segment, the user selection is carded out with the greedy selection algorithm. In the simplified user selection algorithms employing the temporal correlation （SUSTC）, the selection results are applied for all the remaining slots in each segment. But in the improved simplified user selection algorithms employing the temporal correlation（ISUSTC）, at the remaining slots, users are kept with favorable channel conditions selected at the previous slot, and other users are updated from the candidate pool to communicate simultaneously. Simulations show that compared with the greedy user selection method, the proposed algorithms can reduce the selection complexity with a little sum capacity loss.
文摘A direct conversion CMOS DVB-S front-end employs a T-configuration variable attenuator,a single-to- differential low noise amplifier, and a low noise mixer. By innovative use of the attenuator, the linearity handling ability of the system is dramatically improved. The system is designed and fabricated in SMIC 0.18 μm RF CMOS technology. The measurement data show that the front-end provides a total of more than 30rib dynamic range and a noise figure of 5dB in the wide frequency signal band. The prototype front-end consumes only 10mA and achieves an IIP3 of ＋ 20dBm.
文摘In Bangladesh, more than a dozen of private TV channels are operating and about 10 new channels are waiting with green signal for transmission. Bangladesh Television （BTV）, the only government owned and administered, and known as structurally a biased institution serves the audience the public service information most. At the same time it serves purposes of incumbent government. Public information （PI） broadcast means broadcasting towards public welfare which may bring about change in the betterment of life and work of people. Its main focus would be on information, education, and motivation values rather than entertainment. In case of information, dissemination, and documentation, all private TV channels in Bangladesh serve more entertainment and less public service information, whereas, BTV＇s focus is evident on more PI. The owners and operators of private channels think first of their business profit as well as pressure from government and political parties. During formulating planning and strategies or building program content, they become cautious as they fear that the government become angry and shut down the channel.
基金Project(60872005) supported by National Natural Science Foundation of China
文摘To adjust the variance of source rate in linear broadcast networks, global encoding kernels should have corresponding dimensions to instruct the decoding process. The algorithm of constructing such global encoding kernels is to adjust heterogeneous network to possible link failures. Linear algebra, graph theory and group theory are applied to construct one series of global encoding kernels which are applicable to all source rates. The effectiveness and existence of such global encoding kernels are proved. Based on 2 information flow, the algorithm of construction is explicitly given within polynomial time O（｜E｜ ｜T｜.ω^2max）, and the memory complexity of algorithm is O（｜E｜）. Both time and memory complexity of this algorithm proposed can be O（ωmax） less than those of algorithms in related works.
基金Supported by the National Basic Research Program of China(No.2012CB315905)the National Natural Science Foundation of China(No.61272501)the Fund of Tianjin Key Laboratory of Civil Aircraft Airworthiness and Maintenance in CAUC and a General grant from Civil Aviation Flight University of China(No.J2013-31,Q2014-48)
文摘To enhance the robustness of a proxy multi-signature scheme and improve its efficiency, a novel proxy signature paradigm is proposed referred to as In this paradigm, multiple proxy signer candidates identity-based proxy multi-signature （IBPMS）. are employed to play a role of the single proxy signer in the existing model. A provably secure IBPMS scheme is presented which requires only one round broadcast operation. Performance analysis demonstrates that the new scheme outperforms the existing multi-signature schemes in robustness and communication. These properties are rendered to our IBPMS scheme as a more practical solution to secure e-transaction delegation applications of proxy signatures.
文摘The problem of maintaining data consistency in mobile broadcast environments is researched. Quasi serializability is formally defined and analyzed at first. It was shown that quasi serializability is less stringent than serializability when database consistency is maintained for transactions. Then, corresponding concurrency control protocol that supports both update transactions and read-only transactions is outlined for mobile broadcast environments. Finally, the simulation results confirmed that the proposed protocol could improve the response time significantly.
文摘In order to reduce broadcast storms, improve network security, virtual LAN technology has been widely used in LAN planning. But in many networks, it was be required that computers in different VLAN （Virtual Local Area Network） could be communicated. This article mainly introduced the VLAN classification method inter-VLAN data communication technology, and explained in detail with two simple examples the concrete configure method of the communication between the same cross-switch VLAN traffic and inter-VLAN.
文摘Objective： To analyze the epidemiological characteristics of sexually transmitted infections （STIs） in Guangzhou from 2000 to 2003, in order to provide scientific evidence for control and prevention efforts. Methods： STI reports and demographic data in Guangzhou from 2000 to 2003 were collected and analyzed using the National STD Computer Management Software. Results： The incidence rate of total STIs decreased.The incidence of syphilis, gonorrhea and condyloma acuminata decreased yearly from 41.71/100,000,70.13/100,000 and 83.02/100,000 in 2000 to 32.36/100,000,54.35/100,000 and 67.03/100,000 in 2003, respectively.The incidence of HIV/AIDS increased yearly.Nongonococcal urethritis （cervicitis） was the most prevalent STI. Conclusions： Incidence of STIs in Guangzhou is decreasing overall, but the incidence of HIV/AIDS is increasing and there is a change in the pattern of STI epidemics. Efforts should be made to keep the epidemic under control.
文摘Such an extremely difficult issue as cultural diversity is confronted by the existence and evolution of enterprises with the rapid development of global economy of the present. If the establishment is to boost competitiveness, it must have a quite good knowledge of target market so as to formulate some efficient strategies of broadcasting in its management, and the best way to resolve such problem is to eliminate cultural barriers with the adoption of the transmission of cross-cultural advertisements. This thesis shall research cultural diversities between eastern nations and western ones, and explore the effect the diversities have upon cross-cultural transmission, thus to propose an approach of eliminating cultural isolation with the adoption of effective techniques and manners of the transmission of cross-cultural advertisements.
