PANCREATIC tuberculosis(TB)is a rare disease and its diagnosis is difficult because of the lack of specific clinical manifestations.Computed tomography(CT)and magnetic resonance imaging(MRI)have some diagnostic values...PANCREATIC tuberculosis(TB)is a rare disease and its diagnosis is difficult because of the lack of specific clinical manifestations.Computed tomography(CT)and magnetic resonance imaging(MRI)have some diagnostic values in this disease,but it is easy to misdiagnose pancreatic TB as a pancreatic tumor.1 In this article,we present a case of non-immunocompromised patient developing an isolated pancreatic TB,report the CT and MRI findings,and the surgical procedure for it.展开更多
Moving target defense(MTD) has emerged as one of the game-changing themes to alter the asymmetric situation between attacks and defenses in cyber-security. Numerous related works involving several facets of MTD have b...Moving target defense(MTD) has emerged as one of the game-changing themes to alter the asymmetric situation between attacks and defenses in cyber-security. Numerous related works involving several facets of MTD have been published. However, comprehensive analyses and research on MTD are still absent. In this paper, we present a survey on MTD technologies to scientifically and systematically introduce, categorize, and summarize the existing research works in this field. First, a new security model is introduced to describe the changes in the traditional defense paradigm and security model caused by the introduction of MTD. A function-and-movement model is provided to give a panoramic overview on different perspectives for understanding the existing MTD research works. Then a systematic interpretation of published literature is presented to describe the state of the art of the three main areas in the MTD field, namely, MTD theory, MTD strategy, and MTD evaluation. Specifically,in the area of MTD strategy, the common characteristics shared by the MTD strategies to improve system security and effectiveness are identified and extrapolated. Thereafter, the methods to implement these characteristics are concluded. Moreover, the MTD strategies are classified into three types according to their specific goals, and the necessary and sufficient conditions of each type to create effective MTD strategies are then summarized, which are typically one or more of the aforementioned characteristics. Finally, we provide a number of observations for the future direction in this field, which can be helpful for subsequent researchers.展开更多
Port address hopping(PAH) communication is a powerful network moving target defense(MTD)mechanism. It was inspired by frequency hopping in wireless communications. One of the critical and difficult issues with PAH is ...Port address hopping(PAH) communication is a powerful network moving target defense(MTD)mechanism. It was inspired by frequency hopping in wireless communications. One of the critical and difficult issues with PAH is synchronization. Existing schemes usually provide hops for each session lasting only a few seconds/minutes, making them easily influenced by network events such as transmission delays, traffic jams, packet dropouts, reordering, and retransmission. To address these problems, in this paper we propose a novel selfsynchronization scheme, called ‘keyed-hashing based self-synchronization(KHSS)'. The proposed method generates the message authentication code(MAC) based on the hash based MAC(HMAC), which is then further used as the synchronization information for port address encoding and decoding. Providing the PAH communication system with one-packet-one-hopping and invisible message authentication abilities enables both clients and servers to constantly change their identities as well as perform message authentication over unreliable communication mediums without synchronization and authentication information transmissions. Theoretical analysis and simulation and experiment results show that the proposed method is effective in defending against man-in-the-middle(MITM) attacks and network scanning. It significantly outperforms existing schemes in terms of both security and hopping efficiency.展开更多
文摘PANCREATIC tuberculosis(TB)is a rare disease and its diagnosis is difficult because of the lack of specific clinical manifestations.Computed tomography(CT)and magnetic resonance imaging(MRI)have some diagnostic values in this disease,but it is easy to misdiagnose pancreatic TB as a pancreatic tumor.1 In this article,we present a case of non-immunocompromised patient developing an isolated pancreatic TB,report the CT and MRI findings,and the surgical procedure for it.
基金Project supported by the Natiooal Natural Science Foundation of China （No. 61303264） and the National Basic Research Program （973） of China （Nos. 2012CB315906 and 0800065111001）
基金supported by the National Basic Research Program(973)of China(No.2012CB315906)
文摘Moving target defense(MTD) has emerged as one of the game-changing themes to alter the asymmetric situation between attacks and defenses in cyber-security. Numerous related works involving several facets of MTD have been published. However, comprehensive analyses and research on MTD are still absent. In this paper, we present a survey on MTD technologies to scientifically and systematically introduce, categorize, and summarize the existing research works in this field. First, a new security model is introduced to describe the changes in the traditional defense paradigm and security model caused by the introduction of MTD. A function-and-movement model is provided to give a panoramic overview on different perspectives for understanding the existing MTD research works. Then a systematic interpretation of published literature is presented to describe the state of the art of the three main areas in the MTD field, namely, MTD theory, MTD strategy, and MTD evaluation. Specifically,in the area of MTD strategy, the common characteristics shared by the MTD strategies to improve system security and effectiveness are identified and extrapolated. Thereafter, the methods to implement these characteristics are concluded. Moreover, the MTD strategies are classified into three types according to their specific goals, and the necessary and sufficient conditions of each type to create effective MTD strategies are then summarized, which are typically one or more of the aforementioned characteristics. Finally, we provide a number of observations for the future direction in this field, which can be helpful for subsequent researchers.
基金Project supported by the National Basic Research Program(973)of China(No.2012CB315906)the National Natural Science Foundation of China(No.61303264)
文摘Port address hopping(PAH) communication is a powerful network moving target defense(MTD)mechanism. It was inspired by frequency hopping in wireless communications. One of the critical and difficult issues with PAH is synchronization. Existing schemes usually provide hops for each session lasting only a few seconds/minutes, making them easily influenced by network events such as transmission delays, traffic jams, packet dropouts, reordering, and retransmission. To address these problems, in this paper we propose a novel selfsynchronization scheme, called ‘keyed-hashing based self-synchronization(KHSS)'. The proposed method generates the message authentication code(MAC) based on the hash based MAC(HMAC), which is then further used as the synchronization information for port address encoding and decoding. Providing the PAH communication system with one-packet-one-hopping and invisible message authentication abilities enables both clients and servers to constantly change their identities as well as perform message authentication over unreliable communication mediums without synchronization and authentication information transmissions. Theoretical analysis and simulation and experiment results show that the proposed method is effective in defending against man-in-the-middle(MITM) attacks and network scanning. It significantly outperforms existing schemes in terms of both security and hopping efficiency.
