To understand the characteristics of impact-sound transmission through a floor is very helpful for developing sound attenuation strategies to acquire a high quality of dwellings. Sound transmission through a floating ...To understand the characteristics of impact-sound transmission through a floor is very helpful for developing sound attenuation strategies to acquire a high quality of dwellings. Sound transmission through a floating floor to the room underneath was modeled by finite-element method (FEM). The sound pressure levels calculated by the FEM model on a scale of 1:4 was compared with the measured values, which demonstrate good agreement, particularly for impact sound of a relatively low frequency. The sound pressure level in a receiving room is strongly affected by the structural characteristics of both the floor and the room. The sound pressure transmitted through a clamped floor is lower than through a simply supported floor because of the larger rigidity of the clamped floor that contributes to the attenuation mechanism of stiffness. Increase in the thickness of the fiber-glass damping layer in the floor improves sound insulation. A larger room has a larger capacity to dissipate the sound pressure and thus has a lower sound pressure level. An asymmetric configuration of room avails sound attenuation because it has weaker structural and acoustic coupling than a symmetric one.展开更多
IPsec has become an important supplement of IP to provide security protection. However, the heavyweight IPsec has a high transmission overhead and latency, and it cannot provide the address accountability. We propose ...IPsec has become an important supplement of IP to provide security protection. However, the heavyweight IPsec has a high transmission overhead and latency, and it cannot provide the address accountability. We propose the self-trustworthy and secure Internet protocol(T-IP) for authenticated and encrypted network layer communications. T-IP has the following advantages:(1) Self-Trustworthy IP address.(2) Low connection latency and transmission overhead.(3) Reserving the important merit of IP to be stateless.(4) Compatible with the existing TCP/IP architecture. We theoretically prove the security of our shared secret key in T-IP and the resistance to the known session key attack of our security-enhanced shared secret key calculation. Moreover, we analyse the possibility of the application of T-IP, including its resilience against the man-in-the-middle attack and Do S attack. The evaluation shows that T-IP has a much lower transmission overhead and connection latency compared with IPsec.展开更多
基金the Excellent Young Teacher Foundation of Henan Province under the grant No. [2005]461.
文摘To understand the characteristics of impact-sound transmission through a floor is very helpful for developing sound attenuation strategies to acquire a high quality of dwellings. Sound transmission through a floating floor to the room underneath was modeled by finite-element method (FEM). The sound pressure levels calculated by the FEM model on a scale of 1:4 was compared with the measured values, which demonstrate good agreement, particularly for impact sound of a relatively low frequency. The sound pressure level in a receiving room is strongly affected by the structural characteristics of both the floor and the room. The sound pressure transmitted through a clamped floor is lower than through a simply supported floor because of the larger rigidity of the clamped floor that contributes to the attenuation mechanism of stiffness. Increase in the thickness of the fiber-glass damping layer in the floor improves sound insulation. A larger room has a larger capacity to dissipate the sound pressure and thus has a lower sound pressure level. An asymmetric configuration of room avails sound attenuation because it has weaker structural and acoustic coupling than a symmetric one.
基金supported by the national key research and development program under grant 2017YFB0802301Guangxi cloud computing and large data Collaborative Innovation Center Project
文摘IPsec has become an important supplement of IP to provide security protection. However, the heavyweight IPsec has a high transmission overhead and latency, and it cannot provide the address accountability. We propose the self-trustworthy and secure Internet protocol(T-IP) for authenticated and encrypted network layer communications. T-IP has the following advantages:(1) Self-Trustworthy IP address.(2) Low connection latency and transmission overhead.(3) Reserving the important merit of IP to be stateless.(4) Compatible with the existing TCP/IP architecture. We theoretically prove the security of our shared secret key in T-IP and the resistance to the known session key attack of our security-enhanced shared secret key calculation. Moreover, we analyse the possibility of the application of T-IP, including its resilience against the man-in-the-middle attack and Do S attack. The evaluation shows that T-IP has a much lower transmission overhead and connection latency compared with IPsec.
