In this paper, the channel estimation techniques for Orthogonal Frequency Division Multiplexing （OFDM） systems based on pilot arrangement are studied and we apply Low Density Parity Check （LDPC） codes to the syste...In this paper, the channel estimation techniques for Orthogonal Frequency Division Multiplexing （OFDM） systems based on pilot arrangement are studied and we apply Low Density Parity Check （LDPC） codes to the system of IEEE 802.16a with OFDM modulation. First investigated is the influence of channel cstimation schemes on LDPC-code based OFDM system in static and multipath fading channels. According to the different propagation environments in 802.16a system, a dynamic channel estimation scheme is proposed. A good irregular LDPC code is designed with code rate of 1/2 and code length of 1200. Simulation results show that the performance of LDPC coded OFDM system proposed in this paper is better than that of the convolution Turbo coded OFDM system proposed in IEEE standard 802.16a.展开更多
A new scheduling algorithm, which aims to provide proportional and controllable QoS (Quality of Service) in terms of burst loss probability for OBS (Optical Burst Switching) networks, is proposed on the ba- sis of a s...A new scheduling algorithm, which aims to provide proportional and controllable QoS (Quality of Service) in terms of burst loss probability for OBS (Optical Burst Switching) networks, is proposed on the ba- sis of a survey of QoS schemes in current OBS networks. With simulations, performance analysis and com- parisons are carried out in detail. The results show that, in the proposed scheme, burst loss probabilities are proportional to the given factors and the control of QoS performance can be achieved with better performance. This scheme will be beneficial to the OBS network management and the tariff policy making.展开更多
Objectives: To estimate the average cost per screening offer, cost per testin g episode and cost per chlamydia positive episode for an opportunistic chlamydia screening programme(including partner management), and to ...Objectives: To estimate the average cost per screening offer, cost per testin g episode and cost per chlamydia positive episode for an opportunistic chlamydia screening programme(including partner management), and to explore the uncertain ty of parameter assumptions, based on the costs to the healthcare system. Method s: A decision tree was constructed and parameterised using empirical data from a chlamydia screening pilot study and other sources. The model was run using base line data from the pilot, and univariate and multivariate sensitivity analyses w ere conducted. Results: The total estimated cost for offering screening over 12 months to 33 215 females aged 16- 24 was ￡ 493 412. The average cost (with par tner management) was ￡ 14.88 per screening offer (90% credibility interval (C I) 10.34 to 18.56), ￡ 21.83 per testing episode (90% CI 18.16 to 24.20)- , a nd ￡ 38.36 per positive episode (90% CI 33.97 to 42.25). The proportion of in dividuals accepting screening, the clinician (general practitioner/nurse) time a nd their relative involvement in discussing screening, the test cost, the time t o notify patients of their results, and the receptionist time recruiting patient s had the greatest impact on the outcomes in both the univariate and multivariate sensitivity analyses. Conclusions: Re sults from this costing study may be used to inform resource allocation for curr ent and future chlamydia screening programme implementation.展开更多
In the theoretical study of numerical solution of stiff ODEs, it usually assumes that the righthand function f(y) satisfy one-side Lipschitz condition < f(y) - f(z),y - z >less than or equal to v(1)parallel to y...In the theoretical study of numerical solution of stiff ODEs, it usually assumes that the righthand function f(y) satisfy one-side Lipschitz condition < f(y) - f(z),y - z >less than or equal to v(1)parallel to y - z parallel to(2),f : Omega subset of or equal to C-m --> C-m, or another related one-side Lipschitz condition [F(Y) - F(Z), Y - Z](D) less than or equal to v'parallel to Y - Z parallel to(D)(2), F : Omega(s) subset of or equal to C-ms --> C-ms, this paper demonstrates that the difference of the two sets of all functions satisfying the above two conditions respectively is at most that v' - v' only is constant independent of stiffness of function f.展开更多
Objective This study aimed to estimate the temporal trends and subtype of acute myocardial infarction(AMI)and association with modifiable risk factors of cardiovascular disease in Chinese young adults hospitalized wit...Objective This study aimed to estimate the temporal trends and subtype of acute myocardial infarction(AMI)and association with modifiable risk factors of cardiovascular disease in Chinese young adults hospitalized with first AMI.展开更多
基金Supported by Jiangsu University Natural Science Re-search Fund (05KJB510090), National Natural Science Foundation of China (No.60472104).
文摘In this paper, the channel estimation techniques for Orthogonal Frequency Division Multiplexing （OFDM） systems based on pilot arrangement are studied and we apply Low Density Parity Check （LDPC） codes to the system of IEEE 802.16a with OFDM modulation. First investigated is the influence of channel cstimation schemes on LDPC-code based OFDM system in static and multipath fading channels. According to the different propagation environments in 802.16a system, a dynamic channel estimation scheme is proposed. A good irregular LDPC code is designed with code rate of 1/2 and code length of 1200. Simulation results show that the performance of LDPC coded OFDM system proposed in this paper is better than that of the convolution Turbo coded OFDM system proposed in IEEE standard 802.16a.
基金Supported by National Key Project of 863 Program of China (No.2002AA122021), Scientific Research Fund of Chongqing Municipal Education Commission (No.040504 and KJ050504), and Chongqing Science and Technology Commission (CSTC, 2005BB2066).
文摘A new scheduling algorithm, which aims to provide proportional and controllable QoS (Quality of Service) in terms of burst loss probability for OBS (Optical Burst Switching) networks, is proposed on the ba- sis of a survey of QoS schemes in current OBS networks. With simulations, performance analysis and com- parisons are carried out in detail. The results show that, in the proposed scheme, burst loss probabilities are proportional to the given factors and the control of QoS performance can be achieved with better performance. This scheme will be beneficial to the OBS network management and the tariff policy making.
文摘Objectives: To estimate the average cost per screening offer, cost per testin g episode and cost per chlamydia positive episode for an opportunistic chlamydia screening programme(including partner management), and to explore the uncertain ty of parameter assumptions, based on the costs to the healthcare system. Method s: A decision tree was constructed and parameterised using empirical data from a chlamydia screening pilot study and other sources. The model was run using base line data from the pilot, and univariate and multivariate sensitivity analyses w ere conducted. Results: The total estimated cost for offering screening over 12 months to 33 215 females aged 16- 24 was ￡ 493 412. The average cost (with par tner management) was ￡ 14.88 per screening offer (90% credibility interval (C I) 10.34 to 18.56), ￡ 21.83 per testing episode (90% CI 18.16 to 24.20)- , a nd ￡ 38.36 per positive episode (90% CI 33.97 to 42.25). The proportion of in dividuals accepting screening, the clinician (general practitioner/nurse) time a nd their relative involvement in discussing screening, the test cost, the time t o notify patients of their results, and the receptionist time recruiting patient s had the greatest impact on the outcomes in both the univariate and multivariate sensitivity analyses. Conclusions: Re sults from this costing study may be used to inform resource allocation for curr ent and future chlamydia screening programme implementation.
文摘In the theoretical study of numerical solution of stiff ODEs, it usually assumes that the righthand function f(y) satisfy one-side Lipschitz condition < f(y) - f(z),y - z >less than or equal to v(1)parallel to y - z parallel to(2),f : Omega subset of or equal to C-m --> C-m, or another related one-side Lipschitz condition [F(Y) - F(Z), Y - Z](D) less than or equal to v'parallel to Y - Z parallel to(D)(2), F : Omega(s) subset of or equal to C-ms --> C-ms, this paper demonstrates that the difference of the two sets of all functions satisfying the above two conditions respectively is at most that v' - v' only is constant independent of stiffness of function f.
文摘Objective This study aimed to estimate the temporal trends and subtype of acute myocardial infarction(AMI)and association with modifiable risk factors of cardiovascular disease in Chinese young adults hospitalized with first AMI.
