For the large sparse block two-by-two real nonsingular matrices, we establish a general framework of structured preconditioners through matrix transformation and matrix approximations. For the specific versions such a...For the large sparse block two-by-two real nonsingular matrices, we establish a general framework of structured preconditioners through matrix transformation and matrix approximations. For the specific versions such as modified block Jacobi-type, modified block Gauss-Seidel-type, and modified block unsymmetric (symmetric) Gauss-Seidel-type preconditioners, we precisely describe their concrete expressions and deliberately analyze eigenvalue distributions and positive definiteness of the preconditioned matrices. Also, we show that when these structured preconditioners are employed to precondition the Krylov subspace methods such as GMRES and restarted GMRES, fast and effective iteration solvers can be obtained for the large sparse systems of linear equations with block two-by-two coefficient matrices. In particular, these structured preconditioners can lead to high-quality preconditioning matrices for some typical matrices from the real-world applications.展开更多
Objectives: Local digital nerve blockade is frequently used in many trauma cases. Two commonly used techniques of digital nerve block with local anesthetic are the two-injection dorsal technique and the single-injecti...Objectives: Local digital nerve blockade is frequently used in many trauma cases. Two commonly used techniques of digital nerve block with local anesthetic are the two-injection dorsal technique and the single-injection volar subcutaneous technique. In this study we compare various parameters of the single-injection volar subcutaneous block and the two-injection dorsal block. Pain score, amount of injected anesthetic, time of effect onset, patients’ and physicians’ satisfaction scores in each injection technique was compared. Methods: 128 participating patients were randomly divided into two equal experimental groups. Two-percentage Lidocaine was used as an anesthetic agent. Doses of 1.8 and 3-4 ml were used in the single-injection subcutaneous block and the two-injection dorsal block groups, respectively. Following injections, the patients were asked to score their discomfort experience on a standard visual analog scale of 0 (no pain) to 10 (most pain imaginable). They also were asked to score the rate of their satisfaction from 1(no satisfaction) to 5 (most satisfaction). The onset of effect was determined using the pinprick test. Results: Our results demonstrate that the two-injection dorsal block technique imposes more pain but the pain score difference was not statistically significant. Both patients and physicians were more comfortable with the single-injection subcutaneous digital block method. This satisfaction difference was statistically significant. Conclusions: The single-injection method is more efficient and the patients were more pleased. The advantages of this method are its safety, user friendly, need of lower amount of anesthetic drug and its easiness to teach and learn.展开更多
This study focuses on resource block allocation issue in the downlink transmission systems of the Long Term Evolution (LTE). In existing LTE standards, all Allocation Units (AUs) allocated to any user must adopt the s...This study focuses on resource block allocation issue in the downlink transmission systems of the Long Term Evolution (LTE). In existing LTE standards, all Allocation Units (AUs) allocated to any user must adopt the same Modulation and Coding Scheme (MCS), which is determined by the AU with the worst channel condition. Despite its simplicity, this strategy incurs significant performance degradation since the achievable system throughput is limited by the AUs having the worst channel quality. To address this issue, a two-step resource block allocation algorithm is proposed in this paper. The algorithm first allocates AUs to each user according to the users' priorities and the number of their required AUs. Then, a re-allocation mechanism is introduced. Specifically, for any given user, the AUs with the worst channel condition are removed. In this manner, the users may adopt a higher MCS level, and the achievable data rate can be increased. Finally, all the unallocated AUs are assigned among users without changing the chosen MCSs, and the total throughput of the system is further enhanced. Simulation results show that thanks to the proposed algorithm, the system gains higher throughput without adding too many?complexities.展开更多
OBJECTIVE: To compare the clinical effect of brachial plexus block with "One Injection Two Points" guided under ultrasound and the conventional method guiding by ultrasound. METHODS: 70 patients were randomi...OBJECTIVE: To compare the clinical effect of brachial plexus block with "One Injection Two Points" guided under ultrasound and the conventional method guiding by ultrasound. METHODS: 70 patients were randomized evenly into 2 groups, with 35 patients in each group, while the Experiment Group(Group B) received One Injection Two Points" method, the Control Group(Group A) received the conventional method.The nerve block every 5 s, the success rate of anesthesia, the dosage of local anesthetics, second remedial anesthesia, adverse reactions, etc.were recorded. RESULTS: Group B was superior to group A in the success rate of anesthesia; There were 6 patients in group A who required constant pump injection of Remifentanil to remedy, while no patients in Group B needed remedy treatment. There were no serious adverse reactions in both groups.CONCLUSIONS: The clinical effect of brachial plexus block with "One Injection Two Points" method guided under ultrasoundguiding by ultrasound was superior to that of the conventional method.展开更多
文摘For the large sparse block two-by-two real nonsingular matrices, we establish a general framework of structured preconditioners through matrix transformation and matrix approximations. For the specific versions such as modified block Jacobi-type, modified block Gauss-Seidel-type, and modified block unsymmetric (symmetric) Gauss-Seidel-type preconditioners, we precisely describe their concrete expressions and deliberately analyze eigenvalue distributions and positive definiteness of the preconditioned matrices. Also, we show that when these structured preconditioners are employed to precondition the Krylov subspace methods such as GMRES and restarted GMRES, fast and effective iteration solvers can be obtained for the large sparse systems of linear equations with block two-by-two coefficient matrices. In particular, these structured preconditioners can lead to high-quality preconditioning matrices for some typical matrices from the real-world applications.
文摘Objectives: Local digital nerve blockade is frequently used in many trauma cases. Two commonly used techniques of digital nerve block with local anesthetic are the two-injection dorsal technique and the single-injection volar subcutaneous technique. In this study we compare various parameters of the single-injection volar subcutaneous block and the two-injection dorsal block. Pain score, amount of injected anesthetic, time of effect onset, patients’ and physicians’ satisfaction scores in each injection technique was compared. Methods: 128 participating patients were randomly divided into two equal experimental groups. Two-percentage Lidocaine was used as an anesthetic agent. Doses of 1.8 and 3-4 ml were used in the single-injection subcutaneous block and the two-injection dorsal block groups, respectively. Following injections, the patients were asked to score their discomfort experience on a standard visual analog scale of 0 (no pain) to 10 (most pain imaginable). They also were asked to score the rate of their satisfaction from 1(no satisfaction) to 5 (most satisfaction). The onset of effect was determined using the pinprick test. Results: Our results demonstrate that the two-injection dorsal block technique imposes more pain but the pain score difference was not statistically significant. Both patients and physicians were more comfortable with the single-injection subcutaneous digital block method. This satisfaction difference was statistically significant. Conclusions: The single-injection method is more efficient and the patients were more pleased. The advantages of this method are its safety, user friendly, need of lower amount of anesthetic drug and its easiness to teach and learn.
文摘This study focuses on resource block allocation issue in the downlink transmission systems of the Long Term Evolution (LTE). In existing LTE standards, all Allocation Units (AUs) allocated to any user must adopt the same Modulation and Coding Scheme (MCS), which is determined by the AU with the worst channel condition. Despite its simplicity, this strategy incurs significant performance degradation since the achievable system throughput is limited by the AUs having the worst channel quality. To address this issue, a two-step resource block allocation algorithm is proposed in this paper. The algorithm first allocates AUs to each user according to the users' priorities and the number of their required AUs. Then, a re-allocation mechanism is introduced. Specifically, for any given user, the AUs with the worst channel condition are removed. In this manner, the users may adopt a higher MCS level, and the achievable data rate can be increased. Finally, all the unallocated AUs are assigned among users without changing the chosen MCSs, and the total throughput of the system is further enhanced. Simulation results show that thanks to the proposed algorithm, the system gains higher throughput without adding too many?complexities.
文摘OBJECTIVE: To compare the clinical effect of brachial plexus block with "One Injection Two Points" guided under ultrasound and the conventional method guiding by ultrasound. METHODS: 70 patients were randomized evenly into 2 groups, with 35 patients in each group, while the Experiment Group(Group B) received One Injection Two Points" method, the Control Group(Group A) received the conventional method.The nerve block every 5 s, the success rate of anesthesia, the dosage of local anesthetics, second remedial anesthesia, adverse reactions, etc.were recorded. RESULTS: Group B was superior to group A in the success rate of anesthesia; There were 6 patients in group A who required constant pump injection of Remifentanil to remedy, while no patients in Group B needed remedy treatment. There were no serious adverse reactions in both groups.CONCLUSIONS: The clinical effect of brachial plexus block with "One Injection Two Points" method guided under ultrasoundguiding by ultrasound was superior to that of the conventional method.
