针对全IP融合网络环境下的垃圾语音信息(spam over Internet telephony,SPIT)隐患,提出了一种基于反馈评判的检测与防范方法.该方法引入了终端用户的参与,结合信任与信誉机制,能够简单、高效、无损地利用直接和间接的反馈信息.改进的信...针对全IP融合网络环境下的垃圾语音信息(spam over Internet telephony,SPIT)隐患,提出了一种基于反馈评判的检测与防范方法.该方法引入了终端用户的参与,结合信任与信誉机制,能够简单、高效、无损地利用直接和间接的反馈信息.改进的信任度与信誉度推理算法充分体现了SPIT行为的分布特性并反映了影响评判结果的各因素的权重关系.增量学习算法保证了信任度和信誉度的实时性,融合算法则动态调整了信任度和信誉度在评判中的角色.实验及分析表明上述方法具有较好的准确性和敏感性,能够对SPIT进行有效的检测及防范.展开更多
针对基于SIP协议的SPIT攻击(Spam over Internet Telephony,SPIT),提出一种基于统计的SPIT检测方法。该方法提取用户多个行为属性和采用D-S理论将多个属性进行融合,实现对多种攻击方式的检测。同时,对域进行分类有区别地考虑域发动攻击...针对基于SIP协议的SPIT攻击(Spam over Internet Telephony,SPIT),提出一种基于统计的SPIT检测方法。该方法提取用户多个行为属性和采用D-S理论将多个属性进行融合,实现对多种攻击方式的检测。同时,对域进行分类有区别地考虑域发动攻击的可能性和用户的合法性,提高了检测的准确性。实验及分析表明上述方法具有较好的准确性,能够针对SPIT进行有效的检测。展开更多
By using satellite remote sensing informations, the conceptual system of time-space at tributes and time dimension in recent evolution of the sand spit at the Huanghe River mouth is expound ed. Based on this work, the...By using satellite remote sensing informations, the conceptual system of time-space at tributes and time dimension in recent evolution of the sand spit at the Huanghe River mouth is expound ed. Based on this work, the parameterization of relevant factors and topological analysis of sand spit spa tial structure are conducted, and a model, which is suitable for representing the development and growth of the Huanghe River mouth is developed. It is shown that during the later stage of its development, the Sand spit growth index is almost 0. According to the parallelogram rule, under the reinforce effects of the Coriolis force and ocean dynamics, the Sand spit of current stream will never extend towards sea when it reaches the deep-water area. This work would be helpful to the imminent comprehensive harness of the 'man-made river branch' at the Huanghe River mouth.展开更多
随着固定移动融合(Fixed Mobile Convergence,FMC)网络的发展,基于会话初始协议(Session Initial Protocol,SIP)的VoIP(Voice over IP)无疑将成为全IP融合网络环境下最为重要的业务应用。然而SIP在设计之初便存在诸多安全隐患,VoIP又是...随着固定移动融合(Fixed Mobile Convergence,FMC)网络的发展,基于会话初始协议(Session Initial Protocol,SIP)的VoIP(Voice over IP)无疑将成为全IP融合网络环境下最为重要的业务应用。然而SIP在设计之初便存在诸多安全隐患,VoIP又是采用开放、互通的应用模式,因此垃圾语音信息(Spam over Internet Telephony,SPIT)作为一种非预期的语音发送行为,成为全IP语音业务发展中的重要安全威胁。展开更多
以经典单向函数为基础,设计并验证了一种用于垃圾语音(Spam over Internet Telephony,SPIT)防范的方法.该方法利用资源挑战机制,要求垃圾语音的发送者消耗大量系统资源来破解谜题才可以发送语言会话请求.谜题设计算法避免了相关研究存...以经典单向函数为基础,设计并验证了一种用于垃圾语音(Spam over Internet Telephony,SPIT)防范的方法.该方法利用资源挑战机制,要求垃圾语音的发送者消耗大量系统资源来破解谜题才可以发送语言会话请求.谜题设计算法避免了相关研究存在的缺陷,使得方法更加安全、可靠;谜题破解算法要求发送者对CPU与Memory进行双重消耗,从而缩小不同配置终端在破解过程中的消耗差距.对方法进行仿真实验,分析结果表明方法具有很好的有效性与适用性.展开更多
Eu2+, Dy3+-doped SrAl2O4 was prepared by a hydrothermal reaction through the process of calcination at lower temperature. The physicochemical properties of the SrAl2O4: Eu2+, Dy3+ phosphor were characterized and compa...Eu2+, Dy3+-doped SrAl2O4 was prepared by a hydrothermal reaction through the process of calcination at lower temperature. The physicochemical properties of the SrAl2O4: Eu2+, Dy3+ phosphor were characterized and compared to those of the SrAl2O4: Eu2+, Dy3+ prepared by sol-gel method. The photocatalytic properties of the SrAl2O4: Eu2+, Dy3+ were evaluated in photocatalytic water decomposition for hydrogen production. The SrAl2O4: Eu2+, Dy3+ prepared by hydrothermal reaction exhibited excellent phosphor properties which were similar with that prepared by sol-gel method. Its photocatalytic activity for hydrogen evolution was higher than that of TiO2 photocatalyst.展开更多
1. In spite of the title, this article will really be on how not to grow old, which, at my time of life, is a much more important subject. My first advice would be to choose your ancestors carefully. Although both my ...1. In spite of the title, this article will really be on how not to grow old, which, at my time of life, is a much more important subject. My first advice would be to choose your ancestors carefully. Although both my parents died young, I have done well in this respect as regards my other ancestors. My maternal grandfather, it is true, was cut off in the flower of his youth at the age of sixty-seven,展开更多
Two rectangular-shaped lakes,Lake Hulun and Lake Buir,located at the boundary between China and Mongolia,only c.75 km apart and therefore experiencing similar wind fields,have been studied based on satellite images an...Two rectangular-shaped lakes,Lake Hulun and Lake Buir,located at the boundary between China and Mongolia,only c.75 km apart and therefore experiencing similar wind fields,have been studied based on satellite images and field surveys in order to compare their geomorphological and sedimentological characteristics.The wind-driven hydrodynamics,which have a significant effect on the development of littoral landforms and on sediment distribution,have been discussed for the two similar lakes that experienced a prevailing wind perpendicular to their long axis.A conceptual model related to wind-driven water bodies and sediment distribution is proposed.Wave-influenced to wave-dominated deltas,beaches,spits,and eolian dune deposits develop around these two lakes,with a strikingly similar distribution pattern.These features locally inform the longshore drift and help reconstruct the water circulation induced by wind forcing.Under the NW prevailing wind regime,the spits developed on the SW coast with a NW—SE extension,which was influenced by the NW—SE longshore currents.The same influence was observed in the delta extension in the NE area.The differences lie in the presence of fan deltas in the NW region of Lake Hulun,but not in Lake Buir.Additionally,the width of the beach and eolian deposits on the downwind coast of Lake Hulun is three times greater than that of Lake Buir which were caused by the differences in sediment supply and wind fetch between the two lakes.Lake Hulun and Lake Buir provide two reliable examples to understand the relationship among the wind field,provenance,hydrodynamics,landforms,and asymmetrical distribution of clastics in elongated lakes.They also represent relevant modern analogs,which may also be of guiding significance to wind-driven sand body prediction in lacustrine basins.展开更多
Robo or unsolicited calls have become a persistent issue in telecommunication networks,posing significant challenges to individuals,businesses,and regulatory authorities.These calls not only trick users into disclosin...Robo or unsolicited calls have become a persistent issue in telecommunication networks,posing significant challenges to individuals,businesses,and regulatory authorities.These calls not only trick users into disclosing their private and financial information,but also affect their productivity through unwanted phone ringing.A proactive approach to identify and block such unsolicited calls is essential to protect users and service providers from potential harm.Therein,this paper proposes a solution to identify robo-callers in the telephony network utilising a set of novel features to evaluate the trustworthiness of callers in a network.The trust score of the callers is then used along with machine learning models to classify them as legitimate or robo-caller.We use a large anonymized dataset(call detailed records)from a large telecommunication provider containing more than 1 billion records collected over 10 days.We have conducted extensive evaluation demonstrating that the proposed approach achieves high accuracy and detection rate whilst minimizing the error rate.Specifically,the proposed features when used collectively achieve a true-positive rate of around 97%with a false-positive rate of less than 0.01%.展开更多
Last fall the British Council held a contest asking people to submit their favorite Beijing sounds as part of a project drawing attention to sound and daily life in the city. Entries were later posted online, and as I...Last fall the British Council held a contest asking people to submit their favorite Beijing sounds as part of a project drawing attention to sound and daily life in the city. Entries were later posted online, and as I browsed through them, in the first audio file I clicked, there it was. Buried in the usual noises of a bustling street, the backed-up traffic and cries of vendors on bicycle carts, I heard the audible wind-up, like the ripping of Velcro,展开更多
文摘针对全IP融合网络环境下的垃圾语音信息(spam over Internet telephony,SPIT)隐患,提出了一种基于反馈评判的检测与防范方法.该方法引入了终端用户的参与,结合信任与信誉机制,能够简单、高效、无损地利用直接和间接的反馈信息.改进的信任度与信誉度推理算法充分体现了SPIT行为的分布特性并反映了影响评判结果的各因素的权重关系.增量学习算法保证了信任度和信誉度的实时性,融合算法则动态调整了信任度和信誉度在评判中的角色.实验及分析表明上述方法具有较好的准确性和敏感性,能够对SPIT进行有效的检测及防范.
文摘针对基于SIP协议的SPIT攻击(Spam over Internet Telephony,SPIT),提出一种基于统计的SPIT检测方法。该方法提取用户多个行为属性和采用D-S理论将多个属性进行融合,实现对多种攻击方式的检测。同时,对域进行分类有区别地考虑域发动攻击的可能性和用户的合法性,提高了检测的准确性。实验及分析表明上述方法具有较好的准确性,能够针对SPIT进行有效的检测。
基金National Natural Science Foundation of China ! 49871056.
文摘By using satellite remote sensing informations, the conceptual system of time-space at tributes and time dimension in recent evolution of the sand spit at the Huanghe River mouth is expound ed. Based on this work, the parameterization of relevant factors and topological analysis of sand spit spa tial structure are conducted, and a model, which is suitable for representing the development and growth of the Huanghe River mouth is developed. It is shown that during the later stage of its development, the Sand spit growth index is almost 0. According to the parallelogram rule, under the reinforce effects of the Coriolis force and ocean dynamics, the Sand spit of current stream will never extend towards sea when it reaches the deep-water area. This work would be helpful to the imminent comprehensive harness of the 'man-made river branch' at the Huanghe River mouth.
文摘随着固定移动融合(Fixed Mobile Convergence,FMC)网络的发展,基于会话初始协议(Session Initial Protocol,SIP)的VoIP(Voice over IP)无疑将成为全IP融合网络环境下最为重要的业务应用。然而SIP在设计之初便存在诸多安全隐患,VoIP又是采用开放、互通的应用模式,因此垃圾语音信息(Spam over Internet Telephony,SPIT)作为一种非预期的语音发送行为,成为全IP语音业务发展中的重要安全威胁。
文摘以经典单向函数为基础,设计并验证了一种用于垃圾语音(Spam over Internet Telephony,SPIT)防范的方法.该方法利用资源挑战机制,要求垃圾语音的发送者消耗大量系统资源来破解谜题才可以发送语言会话请求.谜题设计算法避免了相关研究存在的缺陷,使得方法更加安全、可靠;谜题破解算法要求发送者对CPU与Memory进行双重消耗,从而缩小不同配置终端在破解过程中的消耗差距.对方法进行仿真实验,分析结果表明方法具有很好的有效性与适用性.
文摘Eu2+, Dy3+-doped SrAl2O4 was prepared by a hydrothermal reaction through the process of calcination at lower temperature. The physicochemical properties of the SrAl2O4: Eu2+, Dy3+ phosphor were characterized and compared to those of the SrAl2O4: Eu2+, Dy3+ prepared by sol-gel method. The photocatalytic properties of the SrAl2O4: Eu2+, Dy3+ were evaluated in photocatalytic water decomposition for hydrogen production. The SrAl2O4: Eu2+, Dy3+ prepared by hydrothermal reaction exhibited excellent phosphor properties which were similar with that prepared by sol-gel method. Its photocatalytic activity for hydrogen evolution was higher than that of TiO2 photocatalyst.
文摘1. In spite of the title, this article will really be on how not to grow old, which, at my time of life, is a much more important subject. My first advice would be to choose your ancestors carefully. Although both my parents died young, I have done well in this respect as regards my other ancestors. My maternal grandfather, it is true, was cut off in the flower of his youth at the age of sixty-seven,
基金supported by the National Science and Technology Special Project(No.2017ZX05009-002)the Fundamental Research Funds for the Central Universitiessupported by CNES through the funding of his postdoctoral fellowship。
文摘Two rectangular-shaped lakes,Lake Hulun and Lake Buir,located at the boundary between China and Mongolia,only c.75 km apart and therefore experiencing similar wind fields,have been studied based on satellite images and field surveys in order to compare their geomorphological and sedimentological characteristics.The wind-driven hydrodynamics,which have a significant effect on the development of littoral landforms and on sediment distribution,have been discussed for the two similar lakes that experienced a prevailing wind perpendicular to their long axis.A conceptual model related to wind-driven water bodies and sediment distribution is proposed.Wave-influenced to wave-dominated deltas,beaches,spits,and eolian dune deposits develop around these two lakes,with a strikingly similar distribution pattern.These features locally inform the longshore drift and help reconstruct the water circulation induced by wind forcing.Under the NW prevailing wind regime,the spits developed on the SW coast with a NW—SE extension,which was influenced by the NW—SE longshore currents.The same influence was observed in the delta extension in the NE area.The differences lie in the presence of fan deltas in the NW region of Lake Hulun,but not in Lake Buir.Additionally,the width of the beach and eolian deposits on the downwind coast of Lake Hulun is three times greater than that of Lake Buir which were caused by the differences in sediment supply and wind fetch between the two lakes.Lake Hulun and Lake Buir provide two reliable examples to understand the relationship among the wind field,provenance,hydrodynamics,landforms,and asymmetrical distribution of clastics in elongated lakes.They also represent relevant modern analogs,which may also be of guiding significance to wind-driven sand body prediction in lacustrine basins.
文摘Robo or unsolicited calls have become a persistent issue in telecommunication networks,posing significant challenges to individuals,businesses,and regulatory authorities.These calls not only trick users into disclosing their private and financial information,but also affect their productivity through unwanted phone ringing.A proactive approach to identify and block such unsolicited calls is essential to protect users and service providers from potential harm.Therein,this paper proposes a solution to identify robo-callers in the telephony network utilising a set of novel features to evaluate the trustworthiness of callers in a network.The trust score of the callers is then used along with machine learning models to classify them as legitimate or robo-caller.We use a large anonymized dataset(call detailed records)from a large telecommunication provider containing more than 1 billion records collected over 10 days.We have conducted extensive evaluation demonstrating that the proposed approach achieves high accuracy and detection rate whilst minimizing the error rate.Specifically,the proposed features when used collectively achieve a true-positive rate of around 97%with a false-positive rate of less than 0.01%.
文摘Last fall the British Council held a contest asking people to submit their favorite Beijing sounds as part of a project drawing attention to sound and daily life in the city. Entries were later posted online, and as I browsed through them, in the first audio file I clicked, there it was. Buried in the usual noises of a bustling street, the backed-up traffic and cries of vendors on bicycle carts, I heard the audible wind-up, like the ripping of Velcro,
