Objective Focusing on the s ecurity problem of authentication and confidentiality in the context of computer networks, a digital signature scheme was proposed based on the public key crypt osystem. Methods Firstly...Objective Focusing on the s ecurity problem of authentication and confidentiality in the context of computer networks, a digital signature scheme was proposed based on the public key crypt osystem. Methods Firstly, the course of digital signature based on the public key cryptosystem was given. Then, RSA and ELGamal schemes were de scribed respectively. They were the basis of the proposed scheme. Generalized EL Gamal type signature schemes were listed. After comparing with each other, one s cheme, whose Signature equation was (m+r)x=j+s modΦ(p) , was adopted in the des igning. Results Based on two well-known cryptographic assumpti ons, the factorization and the discrete logarithms, a digital signature scheme w as presented. It must be required that s' was not equal to p'q' in the signing p rocedure, because attackers could forge the signatures with high probabilities i f the discrete logarithms modulo a large prime were solvable. The variable publi c key “e” is used instead of the invariable parameter “3” in Harn's signatu re scheme to enhance the security. One generalized ELGamal type scheme made the proposed scheme escape one multiplicative inverse operation in the signing proce dure and one modular exponentiation in the verification procedure. Concl usion The presented scheme obtains the security that Harn's scheme was originally claimed. It is secure if the factorization and the discrete logarithm s are simultaneously unsolvable.展开更多
neovascularization /’ni:au. vaskjulorai’zeiIon/n. [l976]the gtowth or spread of new capillaries in the body, especially in a tumor 新血管形成(尤指肿瘤内等体内毛细血管的生长和扩展)
文章把信道分组和PPJET(Preemptive Prioritized Just Enough Time)协议以及光纤延时线三者结合使用,提出了一种新的QoS调度方案D-PPJET(Developed-PPJET)协议。在该协议下,高优先级数据包可以被动态地调度到任何可用的信道上去,而低优...文章把信道分组和PPJET(Preemptive Prioritized Just Enough Time)协议以及光纤延时线三者结合使用,提出了一种新的QoS调度方案D-PPJET(Developed-PPJET)协议。在该协议下,高优先级数据包可以被动态地调度到任何可用的信道上去,而低优先级数据包只能在规定的部分信道上调度,并利用光纤延时线(FDL)缓存机制为未成功调度的突发包提供二次调度的机会,这样高优先级业务包调度成功的机会就大大增加,为高优先级业务提供了保证,同时还使得低优先级突发分组丢失率下降。结果表明它能够大大地改善整个网络突发包的丢失率、信道吞吐量及信道利用率。展开更多
A polycrystalline dense Ti3SiC2 based ceramic material has been produced by several techniques. The effect of addition of TiC and SiC is also studied. The Ti3SiC2 material shows extraordinary electrical, thermal and m...A polycrystalline dense Ti3SiC2 based ceramic material has been produced by several techniques. The effect of addition of TiC and SiC is also studied. The Ti3SiC2 material shows extraordinary electrical, thermal and mechanical properties. Furthermore, it shows a damage tolerance capability and oxidation resistance. In this work, we have synthesized Ti3SiC2 by electro-thermal explosion chemical reaction (ETE) with high current density (900 Amperes/a.u) followed by uniaxial pressure. The structural properties of the as-prepared materials are studied by x-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive x-ray spectroscopy (EDX) techniques. The chemical cartography, imaging and electronic properties are investigated using Ultra-STEM and electron high energy loss resolution spectroscopy (EELS) techniques, respectively. The surface of Ti3SiC2 is characterized by means of X-ray photoelectron spectroscopy (XPS). High resolution C 1s, Si 2p, Ti 2p, Ti 3s core level spectra are explained in terms of crystallographic and electronic structure. Valence band spectrum is performed to confirm the validity of the theoretical calculations.展开更多
For trapped users in disaster areas,the available energy of affected user equipment(UE)is limited due to the breakdown of the ground power system.When complex geographical condition prevents ground emergency vehicles ...For trapped users in disaster areas,the available energy of affected user equipment(UE)is limited due to the breakdown of the ground power system.When complex geographical condition prevents ground emergency vehicles from reaching disaster-stricken areas,unmanned aerial vehicle(UAV)can effectively work as a temporary aerial base station for serving terrestrial trapped users.Simultaneous wireless information and power transfer(SWIPT)system is intriguing for distributed batteryless users(BUs)by transferring data and energy simultaneously.However,how to achieve the maximum energy efficiency(EE)and energy transfer efficiency(ETE)for distributed BUs in UAV-enabled SWIPT systems is not very clear.In this paper,we develop three novel reconfigurable intelligent surface(RIS)-based SWIPT algorithms to solve this nonconvex joint optimization problem using deep reinforcement learning(RL)algorithms.Through the deployment of RIS-assisted UAVs,we aim to maximize the EE along with the ETE via jointly designing the UAV trajectory,the phase matrix,and the power splitting ratio within strict time and energy constraints.The obtained numerical results show that our developed RL-based algorithms can effectively improve the cost time,the average charging rate,data rate,and the EE/ETE performance of the RIS-assisted SWIPT systems as compared with benchmark solutions.展开更多
Objective To evaluate the diagnostic performance of preoperative multi-b values of DWI and ADC for the prediction of extrathyroidal extension (ETE) of papillary thyroid carcinoma (PTC). Methods Between January 2013 an...Objective To evaluate the diagnostic performance of preoperative multi-b values of DWI and ADC for the prediction of extrathyroidal extension (ETE) of papillary thyroid carcinoma (PTC). Methods Between January 2013 and February 2017,MR images including dynamic contrast-enhanced MR imaging (DCE-MRI) and DWI images of 81 patients diagnosed as papillary thyroid carcinoma in the Affiliated Renmin Hospital of Jiangsu University were retrospectively analyzed.展开更多
文摘Objective Focusing on the s ecurity problem of authentication and confidentiality in the context of computer networks, a digital signature scheme was proposed based on the public key crypt osystem. Methods Firstly, the course of digital signature based on the public key cryptosystem was given. Then, RSA and ELGamal schemes were de scribed respectively. They were the basis of the proposed scheme. Generalized EL Gamal type signature schemes were listed. After comparing with each other, one s cheme, whose Signature equation was (m+r)x=j+s modΦ(p) , was adopted in the des igning. Results Based on two well-known cryptographic assumpti ons, the factorization and the discrete logarithms, a digital signature scheme w as presented. It must be required that s' was not equal to p'q' in the signing p rocedure, because attackers could forge the signatures with high probabilities i f the discrete logarithms modulo a large prime were solvable. The variable publi c key “e” is used instead of the invariable parameter “3” in Harn's signatu re scheme to enhance the security. One generalized ELGamal type scheme made the proposed scheme escape one multiplicative inverse operation in the signing proce dure and one modular exponentiation in the verification procedure. Concl usion The presented scheme obtains the security that Harn's scheme was originally claimed. It is secure if the factorization and the discrete logarithm s are simultaneously unsolvable.
文摘neovascularization /’ni:au. vaskjulorai’zeiIon/n. [l976]the gtowth or spread of new capillaries in the body, especially in a tumor 新血管形成(尤指肿瘤内等体内毛细血管的生长和扩展)
文摘文章把信道分组和PPJET(Preemptive Prioritized Just Enough Time)协议以及光纤延时线三者结合使用,提出了一种新的QoS调度方案D-PPJET(Developed-PPJET)协议。在该协议下,高优先级数据包可以被动态地调度到任何可用的信道上去,而低优先级数据包只能在规定的部分信道上调度,并利用光纤延时线(FDL)缓存机制为未成功调度的突发包提供二次调度的机会,这样高优先级业务包调度成功的机会就大大增加,为高优先级业务提供了保证,同时还使得低优先级突发分组丢失率下降。结果表明它能够大大地改善整个网络突发包的丢失率、信道吞吐量及信道利用率。
文摘A polycrystalline dense Ti3SiC2 based ceramic material has been produced by several techniques. The effect of addition of TiC and SiC is also studied. The Ti3SiC2 material shows extraordinary electrical, thermal and mechanical properties. Furthermore, it shows a damage tolerance capability and oxidation resistance. In this work, we have synthesized Ti3SiC2 by electro-thermal explosion chemical reaction (ETE) with high current density (900 Amperes/a.u) followed by uniaxial pressure. The structural properties of the as-prepared materials are studied by x-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive x-ray spectroscopy (EDX) techniques. The chemical cartography, imaging and electronic properties are investigated using Ultra-STEM and electron high energy loss resolution spectroscopy (EELS) techniques, respectively. The surface of Ti3SiC2 is characterized by means of X-ray photoelectron spectroscopy (XPS). High resolution C 1s, Si 2p, Ti 2p, Ti 3s core level spectra are explained in terms of crystallographic and electronic structure. Valence band spectrum is performed to confirm the validity of the theoretical calculations.
基金This work was supported by the National Key Research and Development Program of China under Grant 2021YFC3002102.
文摘For trapped users in disaster areas,the available energy of affected user equipment(UE)is limited due to the breakdown of the ground power system.When complex geographical condition prevents ground emergency vehicles from reaching disaster-stricken areas,unmanned aerial vehicle(UAV)can effectively work as a temporary aerial base station for serving terrestrial trapped users.Simultaneous wireless information and power transfer(SWIPT)system is intriguing for distributed batteryless users(BUs)by transferring data and energy simultaneously.However,how to achieve the maximum energy efficiency(EE)and energy transfer efficiency(ETE)for distributed BUs in UAV-enabled SWIPT systems is not very clear.In this paper,we develop three novel reconfigurable intelligent surface(RIS)-based SWIPT algorithms to solve this nonconvex joint optimization problem using deep reinforcement learning(RL)algorithms.Through the deployment of RIS-assisted UAVs,we aim to maximize the EE along with the ETE via jointly designing the UAV trajectory,the phase matrix,and the power splitting ratio within strict time and energy constraints.The obtained numerical results show that our developed RL-based algorithms can effectively improve the cost time,the average charging rate,data rate,and the EE/ETE performance of the RIS-assisted SWIPT systems as compared with benchmark solutions.
文摘Objective To evaluate the diagnostic performance of preoperative multi-b values of DWI and ADC for the prediction of extrathyroidal extension (ETE) of papillary thyroid carcinoma (PTC). Methods Between January 2013 and February 2017,MR images including dynamic contrast-enhanced MR imaging (DCE-MRI) and DWI images of 81 patients diagnosed as papillary thyroid carcinoma in the Affiliated Renmin Hospital of Jiangsu University were retrospectively analyzed.
