目的比较经后外侧入路由后向前三枚空心螺钉三角分布固定与钢板固定治疗累及关节面≥25%后踝骨折的临床疗效。方法回顾性分析南京大学医学院附属苏州医院2016年5月至2022年5月行外科手术治疗的63例后踝骨折患者的临床资料,其中33例行三...目的比较经后外侧入路由后向前三枚空心螺钉三角分布固定与钢板固定治疗累及关节面≥25%后踝骨折的临床疗效。方法回顾性分析南京大学医学院附属苏州医院2016年5月至2022年5月行外科手术治疗的63例后踝骨折患者的临床资料,其中33例行三枚空心螺钉三角分布固定(空心钉组),30例行钢板固定(钢板组)。比较两组患者的术中出血量、手术时间、骨折愈合时间、并发症发生率,以及术后6、12个月及末次随访时踝关节功能评分(American Orthopaedic Foot and Ankle Society,AOFAS)和踝关节活动度(range of motion,ROM)。结果63例患者均得到随访,随访时间为12~48个月,平均(20.5±2.1)个月。两组患者在平均手术时间及并发症发生率方面比较,差异有统计学意义(P<0.05),平均手术时间空心钉组短于钢板组,并发症发生率空心钉组(3.03%)低于钢板组(13.33%);而两组患者的术中出血量及后踝骨折愈合时间比较,差异无统计学意义(P>0.05)。末次随访时优良率比较,空心钉组(90.9%)与钢板组(90.0%)差异无统计学意义(P>0.05)。两组患者随访期间均未出现切口感染、内固定物松动、退出、骨不连等并发症。结论两种方法在治疗此类后踝骨折中均可取得良好的临床疗效,而空心螺钉三角分布固定具有创伤小、并发症少及易于取出等众多优点,是此类后踝骨折内固定有效且经济的方法选择。展开更多
Massive MIMO is a promising technology to improve spectral efficiency, cell coverage, and system capacity for 5G. However, these benefits take place at great cost of computational complexity, especially in systems wit...Massive MIMO is a promising technology to improve spectral efficiency, cell coverage, and system capacity for 5G. However, these benefits take place at great cost of computational complexity, especially in systems with hundreds of antennas at the base station. This paper aims to address the minimum mean square error(MMSE) detection in uplink massive MIMO systems utilizing the symmetric complex bi-conjugate gradients(SCBiCG) and the Lanczos method. Both the proposed methods can avoid the large scale matrix inversion which is necessary for MMSE, thus, reducing the computational complexity by an order of magnitude with respect to the number of user equipment. To enable the proposed methods for soft-output detection, we also derive an approximating calculation scheme for the log-likelihood ratios(LLRs), which further reduces the complexity. We compare the proposed methods with existing exact and approximate detection methods. Simulation results demonstrate that the proposed methods can achieve near-optimal performance of MMSE detection with relatively low computational complexity.展开更多
终端直通(device-to-device,D2D)通信技术已成为第五代移动通信(5G)中的关键技术。资源分配直接关系着D2D通信的质量,是D2D通信中的重要研究内容。该文研究了正交频分多址接入(orthogonal frequency division multiple access,OFDMA)蜂...终端直通(device-to-device,D2D)通信技术已成为第五代移动通信(5G)中的关键技术。资源分配直接关系着D2D通信的质量,是D2D通信中的重要研究内容。该文研究了正交频分多址接入(orthogonal frequency division multiple access,OFDMA)蜂窝网络中的D2D通信,用统计服务质量(quality-of-service,QoS)保证来刻画用户的时延需求,在保证蜂窝用户的干扰门限要求下,以最大化统计带QoS保证的系统吞吐量为目标,提出了有效的资源分配算法。通过Lagrange方法求解原始优化问题,提出了交替式优化算法和渐进凸近似算法。仿真表明,所提方案能有效提升系统性能。展开更多
文摘目的比较经后外侧入路由后向前三枚空心螺钉三角分布固定与钢板固定治疗累及关节面≥25%后踝骨折的临床疗效。方法回顾性分析南京大学医学院附属苏州医院2016年5月至2022年5月行外科手术治疗的63例后踝骨折患者的临床资料,其中33例行三枚空心螺钉三角分布固定(空心钉组),30例行钢板固定(钢板组)。比较两组患者的术中出血量、手术时间、骨折愈合时间、并发症发生率,以及术后6、12个月及末次随访时踝关节功能评分(American Orthopaedic Foot and Ankle Society,AOFAS)和踝关节活动度(range of motion,ROM)。结果63例患者均得到随访,随访时间为12~48个月,平均(20.5±2.1)个月。两组患者在平均手术时间及并发症发生率方面比较,差异有统计学意义(P<0.05),平均手术时间空心钉组短于钢板组,并发症发生率空心钉组(3.03%)低于钢板组(13.33%);而两组患者的术中出血量及后踝骨折愈合时间比较,差异无统计学意义(P>0.05)。末次随访时优良率比较,空心钉组(90.9%)与钢板组(90.0%)差异无统计学意义(P>0.05)。两组患者随访期间均未出现切口感染、内固定物松动、退出、骨不连等并发症。结论两种方法在治疗此类后踝骨折中均可取得良好的临床疗效,而空心螺钉三角分布固定具有创伤小、并发症少及易于取出等众多优点,是此类后踝骨折内固定有效且经济的方法选择。
基金supported by Chinas 863 Project NO.2015AA01A706the National S&T Major Project NO.2014ZX03001011+1 种基金the Science and Technology Program of Beijing NO.D151100000115003the Scientific and Technological Cooperation Projects NO.2015DFT10160B
文摘Massive MIMO is a promising technology to improve spectral efficiency, cell coverage, and system capacity for 5G. However, these benefits take place at great cost of computational complexity, especially in systems with hundreds of antennas at the base station. This paper aims to address the minimum mean square error(MMSE) detection in uplink massive MIMO systems utilizing the symmetric complex bi-conjugate gradients(SCBiCG) and the Lanczos method. Both the proposed methods can avoid the large scale matrix inversion which is necessary for MMSE, thus, reducing the computational complexity by an order of magnitude with respect to the number of user equipment. To enable the proposed methods for soft-output detection, we also derive an approximating calculation scheme for the log-likelihood ratios(LLRs), which further reduces the complexity. We compare the proposed methods with existing exact and approximate detection methods. Simulation results demonstrate that the proposed methods can achieve near-optimal performance of MMSE detection with relatively low computational complexity.
文摘终端直通(device-to-device,D2D)通信技术已成为第五代移动通信(5G)中的关键技术。资源分配直接关系着D2D通信的质量,是D2D通信中的重要研究内容。该文研究了正交频分多址接入(orthogonal frequency division multiple access,OFDMA)蜂窝网络中的D2D通信,用统计服务质量(quality-of-service,QoS)保证来刻画用户的时延需求,在保证蜂窝用户的干扰门限要求下,以最大化统计带QoS保证的系统吞吐量为目标,提出了有效的资源分配算法。通过Lagrange方法求解原始优化问题,提出了交替式优化算法和渐进凸近似算法。仿真表明,所提方案能有效提升系统性能。
