A cooperative model of multiple primary and secondary users coexisting cognitive network is presented. In this model, the control center is aware of all the users＇ locations in order to allocate the nearest secondary...A cooperative model of multiple primary and secondary users coexisting cognitive network is presented. In this model, the control center is aware of all the users＇ locations in order to allocate the nearest secondary user to the primary user. The control center is aware of the information of the unused spectral resources in terms of the feedback of the sensing results from the secondary users. It allocates idle frequency bands among the secondary users. The primary user accesses the base station （BS） in orthogonal subchannels, and it cooperatively transmits packets with the secondary user and exploits the free band assigned by the control center to amplify-and-forward what it receives immediately. Under this scenario, the outage probability of the cooperative transmission pair of the primary and secondary transmitters is derived. The numerical simulation of the outage probabilities as a function of primary transmission probability ps, power allocation ratio ξ between the primary and secondary users, and the numbers of the primary and secondary users are given respectively. The results show that the optimal system performance is achieved under the conditions of ξ=0.5 and the numbers of the primary and the secondary users being equal.展开更多
In Iwamoto-Harada model the whole phase space is full of fermions. When the momentum distributions of the exciton states are taken into account, the pre-formation probability of light composite particles could be impr...In Iwamoto-Harada model the whole phase space is full of fermions. When the momentum distributions of the exciton states are taken into account, the pre-formation probability of light composite particles could be improved, and the exciton state-dependent pre-formation probability has been proposed. The calculated results indicate that the consideration of the momentum distribution enhances the pre-formation probability of [1, m] configuration, and suppresses that of [ι 〉 1, m] configurations seriously.展开更多
Meniscal injury is one of the most common injuries to the knee. The menisci are important for normal knee function. And loss of a meniscus increases the risk of subsequent development of degenerative changes in the kn...Meniscal injury is one of the most common injuries to the knee. The menisci are important for normal knee function. And loss of a meniscus increases the risk of subsequent development of degenerative changes in the knee. Now there are different techniques available for meniscal injury. These techniques include expectant treatment, meniscectomy, meniscal repair, meniscal replacement, and meniscal tissue engineering. Expectant treatment is the appropriate treatment for minor tears of the menisci. Meniscectomy being favored at the beginning is now obsolete. Meniscus repair has become a standard procedure. Meniscal replacement and tissue engineering are used to deal with considerable meniscal injuries. The purpose of this paper is to provide current knowledge regarding the anatomy and function of the menisci, incidence,aetiology, symptoms, signs, investigations and treatments of meniscal injury.展开更多
基金The National Natural Science Foundation of China (No.60972026)the Natural Science Foundation of Jiangsu Province (No.BK2008289)Specialized Research Fund for the Doctoral Program ofHigher Education (No.20090092110009)
文摘A cooperative model of multiple primary and secondary users coexisting cognitive network is presented. In this model, the control center is aware of all the users＇ locations in order to allocate the nearest secondary user to the primary user. The control center is aware of the information of the unused spectral resources in terms of the feedback of the sensing results from the secondary users. It allocates idle frequency bands among the secondary users. The primary user accesses the base station （BS） in orthogonal subchannels, and it cooperatively transmits packets with the secondary user and exploits the free band assigned by the control center to amplify-and-forward what it receives immediately. Under this scenario, the outage probability of the cooperative transmission pair of the primary and secondary transmitters is derived. The numerical simulation of the outage probabilities as a function of primary transmission probability ps, power allocation ratio ξ between the primary and secondary users, and the numbers of the primary and secondary users are given respectively. The results show that the optimal system performance is achieved under the conditions of ξ=0.5 and the numbers of the primary and the secondary users being equal.
文摘In Iwamoto-Harada model the whole phase space is full of fermions. When the momentum distributions of the exciton states are taken into account, the pre-formation probability of light composite particles could be improved, and the exciton state-dependent pre-formation probability has been proposed. The calculated results indicate that the consideration of the momentum distribution enhances the pre-formation probability of [1, m] configuration, and suppresses that of [ι 〉 1, m] configurations seriously.
文摘Meniscal injury is one of the most common injuries to the knee. The menisci are important for normal knee function. And loss of a meniscus increases the risk of subsequent development of degenerative changes in the knee. Now there are different techniques available for meniscal injury. These techniques include expectant treatment, meniscectomy, meniscal repair, meniscal replacement, and meniscal tissue engineering. Expectant treatment is the appropriate treatment for minor tears of the menisci. Meniscectomy being favored at the beginning is now obsolete. Meniscus repair has become a standard procedure. Meniscal replacement and tissue engineering are used to deal with considerable meniscal injuries. The purpose of this paper is to provide current knowledge regarding the anatomy and function of the menisci, incidence,aetiology, symptoms, signs, investigations and treatments of meniscal injury.
