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1.
在雷达跟踪中,算法方案的综合评价可通过DS证据理论进行多属性融合。而在实际应用中存在部分指标缺失等问题,导致证据间出现高冲突,使得原始DS证据合成方法失效。在分析了多指标融合中由于3类信息不完整而导致的高冲突证据后,提出了将算法方案的综合评价作为群体证据,把单个证据与群体证据之间的模糊距离作为证据融合权重,基于权重改进DS证据合成方法,解决了高冲突证据下的多属性融合。实验结果表明基于群体证据模糊距离的DS证据合成方法可以较好地解决雷达跟踪中算法方案综合评价问题。  相似文献   

2.
基于增强的粒子滤波算法的医学图像动态轮廓跟踪新方法   总被引:1,自引:0,他引:1  
关于医学图像的研究,感兴趣区的运动估计和跟踪是一个深受关注的领域。鉴于医学图像质量低、噪声大的普遍特点,从状态变量的非线性、非高斯分布前提出发,利用粒子滤波技术解决该类跟踪问题是一种具有挑战性的技术:由于经典粒子滤波器的权值计算,尤其是重要密度函数的构造方法严重影响了粒子滤波器的性能,本提出了重要改进。针对用粒子滤波方法估计动态轮廓线这一特殊应用,构造了具有特色的似然和先验概率密度算法。结合客观的理论评价标准和大量比较试验,该方法为精确估计动态轮廓线提供了较好的解决对策。  相似文献   

3.
关于医学图像的研究,感兴趣区的运动估计和跟踪是一个深受关注的领域。鉴于医学图像质量低、噪声大的普遍特点,从状态变量的非线性、非高斯分布前提出发,利用粒子滤波技术解决该类跟踪问题是一种具有挑战性的技术:由于经典粒子滤波器的权值计算,尤其是重要密度函数的构造方法严重影响了粒子滤波器的性能,本文提出了重要改进。针对用粒子滤波方法估计动态轮廓线这一特殊应用,构造了具有特色的似然和先验概率密度算法。结合客观的理论评价标准和大量比较试验,该方法为精确估计动态轮廓线提供了较好的解决对策。  相似文献   

4.
研究了基于扩展卡尔曼滤波和粒子滤波的移动机器人位姿估计。由于扩展卡尔曼滤波必须假定噪声服从高斯分布,若用于复杂非线性系统,其估计精度不甚理想。粒子滤波对噪声类型没有限制,正在成为非线性系统状态估计的有效近似方法。在不同噪声条件下,对基于粒子滤波和扩展卡尔曼滤波的移动机器人位姿估计问题进行了比较研究。仿真结果表明:粒子滤波能明显地改善移动机器人位姿估计的鲁棒性和精度。  相似文献   

5.
结合医学图像的特点和频域滤波,对图像的高频部分进行噪声识别,以区分边缘与噪声,再通过改进的空间滤波算法实施去噪,使图像的边缘细节部分得到保护,最后融合处理后的高频图像和其对应的低频图像,获得完整的去噪图像。通过这种方法处理后的图像能达到较好的去噪效果。  相似文献   

6.
在多目标的鲁棒控制系统设计中,使用传统方法通常存在一定的保守性。应用粒子群算法研究多目标的鲁棒控制设计问题,提出了基于多目标粒子群算法H2/H∞鲁棒控制设计方法。数值仿真结果表明:与已有的LMI(线性矩阵不等式)方法相比较,用多目标粒子群算法获得的鲁棒控制器具有更好的鲁棒性能指标,降低了鲁棒控制设计的保守性。  相似文献   

7.
为了提高多目标粒子群算法(MOPSO)的收敛性和多样性,以及增加多目标粒子群算法的适用范围,提出了一种ε约束处理混合三点随机Gbest选择多目标粒子群(ε-TMOPSO)算法。采用一种全新的三点随机Gbest选择机制,用粒子与档案集中非支配解的欧氏距离最近、最远以及处于中间位置的3个粒子构建一个备选池,然后随机选择一个粒子作为Gbest,提高算法的收敛性和多样性;采用改进的带松弛阶段ε约束处理机制处理约束条件,在前期允许加入部分优秀的不可行解,提高算法跳出局部最优的能力;融入Sigmoid函数离散变量编码处理机制,使算法能够处理混合整数问题,增加算法的适用范围。通过测试函数仿真,与EM-MOPSO、NSGA2以及SNSGA算法进行对比,结果表明本文算法在收敛性和分布性上有一定的优势。将该算法应用于乙烯装置蒸汽动力系统优化中取得了较好的效果,进一步证明了该算法的有效性。  相似文献   

8.
针对强机动目标跟踪精度不高的问题,提出了一种强机动目标自适应跟踪算法(HMIMM CV/CAT)。首先通过机动检测区别目标的机动性能,分别应用Kalman滤波和交互多模算法对目标进行跟踪。其次对机动段交互多模算法,给出一组转弯模型离散模型集,在目标机动时通过角速度估计在离散模型集中遴选出一个最匹配的模型参加交互计算,使模型更加逼近目标真实运动模式,且不增加参与交互运算模型数量。蒙特卡罗仿真结果表明,该算法与几种类似算法相比,更加适用于强机动目标。  相似文献   

9.
粒子群优化算法的寻优性能往往会受到控制参数和速度策略的影响。为提高粒子群优化算法的性能,提出了一种基于混合知识的自适应粒子群算法(SPSO-MK)。该算法使用不同的速度更新策略来平衡粒子群优化算法的局部和全局搜索能力,利用在线和先验知识分别对惯性权重和加速因子进行调整。选取32个测试函数进行仿真实验,结果表明本文算法的整体性能好于10种粒子群的变种算法和3种非粒子群算法。将本文算法用于求解3个非合作博弈纳什均衡问题,结果表明该算法能够取得较好的结果。  相似文献   

10.
针对白车身双机器人同步焊接路径规划问题,采用栅格法建立双机器人同步焊接模型。首先通过改进蚁群算法和粒子群算法实现焊接机器人与工件之间的避障;其次通过C空间法实现两个焊接机器人无碰撞,求解出局部和全局最优焊接路径较好的近似解,并与标准蚁群和粒子群算法进行仿真对比实验。仿真结果表明,采用改进蚁群算法和带有交叉因子的粒子群算法,收敛速度较快,较其他算法更能缩短焊接工时。仿真结果验证了笛卡尔空间和C空间结合路径规划方法的可行性,对于双焊接机器人的路径规划具有指导意义。  相似文献   

11.
Neuropsychological impairment in amateur soccer players.   总被引:13,自引:0,他引:13  
E J Matser  A G Kessels  M D Lezak  B D Jordan  J Troost 《JAMA》1999,282(10):971-973
CONTEXT: Soccer players incur concussions during matches and training sessions, as well as numerous subconcussive blows to the head from impacts with the soccer ball (headers). The combination of soccer-related concussions and the number of headers may be a risk for chronic traumatic brain injury (CTBI). OBJECTIVE: To determine whether amateur soccer players have evidence of CTBI. DESIGN, SETTING, AND PARTICIPANTS: Cross-sectional study of 33 amateur soccer players and 27 amateur athletes involved in swimming and track (controls) in the Netherlands who underwent interviews and neuropsychological testing. MAIN OUTCOME MEASURES: Performance of soccer players vs controls on 16 neuropsychological tests having 27 outcomes. RESULTS: Compared with control athletes, amateur soccer players exhibited impaired performance on tests of planning (39% vs 13%; P=.001) and memory (27% vs 7%; P=.004). Among soccer players, 9 (27%) had incurred 1 soccer-related concussion and 7 (23%) had had 2 to 5 concussions during their career. The number of concussions incurred in soccer was inversely related to the neuropsychological performance on 6 of the neuropsychological tests. CONCLUSIONS: Our results indicate that participation in amateur soccer in general and concussion specifically is associated with impaired performance in memory and planning functions. Due to the worldwide popularity of soccer, these observations may have important public health implications.  相似文献   

12.
Psychophysiological requirements of chess players are poorly understood, and periodization of training is often made without any empirical basis. For this reason, the aim of the present study was to investigate the psychophysiological response and quantify the player internal load during, and after playing a chess game. The participant was an elite 33 year-old male chess player ranked among the 300 best chess players in the world. Thus, cortical arousal by critical flicker fusion threshold, electroencephalogram by the theta Fz/alpha Pz ratio and autonomic modulation by heart rate variability were analyzed. Data revealed that cortical arousal by critical flicker fusion threshold and theta Fz/alpha Pz ratio increased and heart rate variability decreased during chess game. All these changes indicated that internal load increased during the chess game. In addition, pre-activation was detected in pre-game measure, suggesting that the prefrontal cortex might be preparatory activated. For these reasons, electroencephalogram, critical flicker fusion threshold and heart rate variability analysis may be highly applicable tools to control and monitor workload in chess player.  相似文献   

13.
目的:探讨棒击法治疗网球肘的作用机制。方法:对典型患网球肘的16名从事运动训练的运动员。采用棒击法辅以按摩治疗。结果:治愈12人、显效3人、好转1人,有效率100%。结论:棒击法辅以按摩的治疗方案。对网球肘具有疗程短、见效快、不易复发的效果。  相似文献   

14.
A Kalenak  C A Morehouse 《JAMA》1975,234(11):1143-1145
Controversy exists on the relationship of knee ligament stability to knee injuries. Subjective evaluation of joint tightness or looseness has been proposed as a criterion for prescribing selective corrective strengthening or stretching exercises. Biomechanical studies of knee ligament stability were performed on 401 college football players from 1969 to 1971. Forty-three knee ligament injuries occurred during this period of time, 19 (44.2%) in "loose-jointed" players and 24 (55.8%) in "tight-jointed" players. Joint laxity tests were performed on 72 college football players; the distribution of college football players failing to perform each of the tests was quite different from that reported for professional football players. There was no relationship between the subjective joint laxity tests and the objective biomechanical tests of knee ligament stability. We conclude that it is not possible to predict knee injuries by subjective evaluations of joint laxity or by objective biomechanical knee ligament evaluations and that exercise programs based on subjective studies are therefore not sound.  相似文献   

15.
OBJECTIVE: To review acute spinal cord injuries (ASCIs) in all Australian codes of football (rugby union [RU], rugby league [RL], Australian Rules football [ARF] and soccer) for 1997-2002 and to compare data with those of a 1986-1996 survey. DESIGN: Retrospective review of hospital records, and structured interviews with injured players. PARTICIPANTS AND SETTING: Patients admitted to any of the six Australian spinal cord injury units with a documented football-related ASCI over the period 1997-2002. OUTCOME MEASURES: Average annual incidence of ASCIs per 100,000 players in the different codes, final Frankel grading of injuries, and wheelchair status. RESULTS: Fifty-two footballers (45 adult men and seven schoolboys) suffered ASCIs between 1997 and 2002. The average annual incidence of ASCIs per 100,000 players was 3.2 for RU, 1.5 for RL, 0.5 for ARF and 0.2 for soccer. While there has been little change in incidence since the 1986-1996 survey, there has been a trend towards less severe injuries in RU and RL, but not in ARF. There have been no scrum injuries in RL since 1996, when the scrum stopped being contested. Seven injuries occurred in RU scrums, six at the moment of engagement of the opposing teams. The incidence of 2-on-1 and "gang" tackles (involving multiple tacklers) in RL is disturbing. Overall, 39% of injured players became permanently wheelchair-dependent. CONCLUSIONS: There continues to be good reason to revise the laws of scrum engagement in RU. The laws relating to multiple tacklers in RL should be examined. The insurance cover for injured players is grossly inadequate. The longstanding need for a registry of spinal cord injuries for all football codes regrettably remains unmet.  相似文献   

16.
Transmission of herpes simplex virus type 1 infection in rugby players   总被引:1,自引:0,他引:1  
W B White  J M Grant-Kels 《JAMA》1984,252(4):533-535
Skin infections, both bacterial and viral, are endemic in contact sports such as wrestling and rugby football. In this report, we describe four cases of extensive cutaneous herpes simplex virus in players on a rugby team. All players had a prodrome of fever, malaise, and anorexia with a weight loss of 3.6 to 9.0 kg. Two players experienced ocular lesions associated with cutaneous vesicular lesions of the face. A third player, who had herpetic lesions on his lower extremity, experienced paresthesias, weakness, and intermittent urinary retention and constipation. All infected players on the team were forwards or members of the "scrum," which suggests a field-acquired infection analogous to the herpetic infections seen in wrestlers (herpes gladiatorum). Considering the serious sequelae of recurrent herpes simplex keratitis, the traumatic skin lesions in rugby football players should be cultured for herpes virus, and infected individuals should be restricted from playing until crusted lesions have disappeared.  相似文献   

17.
Postural stability is an important component of skilled athletic activity. However, the effects of foot orthoses on stability have not been adequately addressed. This study measured postural sway in 30 asymptomatic professional soccer players in three standing positions and four underfoot conditions. The results revealed that the underfoot condition had no significant effect on sway in the mediolateral or anteroposterior planes; however, there was a trend toward less mediolateral sway when subjects stood in a unipedal position with prefabricated orthoses. These results suggest that insoles and foot orthoses have no significant beneficial or detrimental effects on postural stability in asymptomatic subjects. Clinically, this suggests that no improvements in balance performance could be expected with prophylactic use of insoles or orthoses but that clinicians may prescribe insoles and foot orthoses without fear of impairing postural performance in elite athletes.  相似文献   

18.
Concussion in sports. Guidelines for the prevention of catastrophic outcome   总被引:6,自引:1,他引:5  
Concussion (defined as a traumatically induced alteration in mental status, not necessarily with loss of consciousness) is a common form of sports-related injury too often dismissed as trivial by physicians, athletic trainers, coaches, sports reporters, and athletes themselves. While head injuries can occur in virtually any form of athletic activity, they occur most frequently in contact sports, such as football, boxing, and martial arts competition, or from high-velocity collisions or falls in basketball, soccer, and ice hockey. The pathophysiology of concussion is less well understood than that of severe head injury, and it has received less attention as a result. We describe a high school football player who died of diffuse brain swelling after repeated concussions without loss of consciousness. Guidelines have been developed to reduce the risk of such serious catastrophic outcomes after concussion in sports.  相似文献   

19.
Traumatic brain injury in high school athletes.   总被引:8,自引:2,他引:6  
J W Powell  K D Barber-Foss 《JAMA》1999,282(10):958-963
CONTEXT: The potential seriousness of mild traumatic brain injury (MTBI) is increasingly recognized; however, information on the frequency of MTBI among high school athletes is limited. OBJECTIVE: To identify the type, frequency, and severity of MTBI in selected high school sports activities. DESIGN: Observational cohort study. SETTING AND PARTICIPANTS: Two hundred forty-six certified athletic trainers recorded injury and exposure data for high school varsity athletes participating in boys' football, wrestling, baseball and field hockey, girls' volleyball and softball, boys' and girls' basketball, and boys' and girls' soccer at 235 US high schools during 1 or more of the 1995-1997 academic years. MAIN OUTCOME MEASURES: Rates of reported MTBI, defined as a head-injured player who was removed from participation and evaluated by an athletic trainer or physician prior to returning to participation. National incidence figures for MTBI also were estimated. RESULTS: Of 23566 reported injuries in the 10 sports during the 3-year study period, 1219 (5.5%) were MTBIs. Of the MTBIs, football accounted for 773 (63.4%) of cases; wrestling, 128 (10.5%); girls' soccer, 76 (6.2%); boys' soccer, 69 (5.7%); girls' basketball, 63 (5.2%); boys' basketball, 51 (4.2%); softball, 25 (2.1%); baseball, 15 (1.2%); field hockey, 13 (1.1%); and volleyball, 6 (0.5%). The injury rates per 100 player-seasons were 3.66 for football, 1.58 for wrestling, 1.14 for girls' soccer, 1.04 for girls' basketball, 0.92 for boys' soccer, 0.75 for boys' basketball, 0.46 for softball, 0.46 for field hockey, 0.23 for baseball, and 0.14 for volleyball. The median time lost from participation for all MTBIs was 3 days. There were 6 cases of subdural hematoma and intracranial injury reported in football. Based on these data, an estimated 62816 cases of MTBI occur annually among high school varsity athletes participating in these sports, with football accounting for about 63% of cases. CONCLUSIONS: Rates of MTBI vary among sports and none of the 10 popular high school sports we studied is without the occurrence of an MTBI. Continued involvement of high school sports sponsors, researchers, medical professionals, coaches, and sports participants is essential to help minimize the risk of MTBI.  相似文献   

20.
Objective: To analyze injury patterns in a male Japanese professional basketball team of this new league, with a particular focus on the difference between injuries of Asian and non-Asian players.Patients and Methods: During four basketball seasons, we analyzed all injuries in a B2 league team. We investigated the injury rate (IR), game injury rate (GIR), practice injury rate (PIR), pathology, and body area of each injury. Player demographics and injuries were collected from a database, which was updated by the team’s athletic trainer.Results: In total, 47 injuries in 51 players during the 4-year seasons were included. The IRs overall, in Asian, and in non-Asian players were 4.42, 4.37, and 3.11/1000 player hours (PH), respectively. The GIR (47.16/1000 PH overall, 4.37 in Asian, and 3.11 in non-Asians) was significantly higher than the PIR (1.50/1000 PH overall, 1.66 in Asian, and 0.84 in non-Asian; P<0.001 in all groups). Injuries of the upper body occurred only in Asian players (n=17; 51%, P=0.022). Most injuries occurred in the lower extremities than in other body parts (n=30; 64%, P<0.001), for which Asian and non-Asian players showed similar tendencies. Ankle sprains were the most common acute injury (n=7; 15%, P=0.007), while joint problems were the most common chronic injury (n=7; 15%, P=0.046).Conclusion: In this Japanese basketball team, the GIR of Asian, non-Asian, and overall players was higher than that of PIR. Injuries of the upper body were more frequent in Asian players than in non-Asian players in this league. Ankle sprains were the most common injury in both groups, while acute skin injuries occurred predominantly in Asian players. Prevention programs should be developed for injuries of the upper body in Asian players and those with lower extremity injuries.  相似文献   

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