基于多注意力的多变量时间序列特征选择方法     

胡紫音  桂宁 《教育技术导刊》2009,19(11):21-24

特征选择是避免维度诅咒的一种数据预处理技术。在多变量时间序列预测中,为了同时找到与问题相关性最大的变量及其对应时延,提出一种基于多注意力的有监督特征选择方法。该方法利用带有注意力模块和学习模块的深度学习模型,将原始二维时间序列数据正交分割成两组一维数据,分别输入两个不同维度的注意力生成模块,得到特征维度和时间维度的注意权重。两个维度的注意力权值点积叠加作为全局注意力得分进行特征选择,作用于原始数据后输入随学习模块训练不断更新至收敛。实验结果表明,所提出的方法在特征数小于10时可达到全量数据训练效果,与现有几种基线方法相比实现了最佳准确率。  相似文献   

交通信号灯迭代学习控制方法     

姚斐  宋芳 《教育技术导刊》2009,19(8):95-99

由于城市交通信号灯控制存在着非线性动态特性,对其进行控制时很难进行精确的数学建模,同时路口交通流具有重复性特点,呈现明显的周期性特征。为了减少路口车辆等待时间、提高通行效率,利用迭代学习控制方法,对信号灯周期和各个相位有效绿灯时间进行优化,从而对路口绿灯进行最大化利用,保证车辆在路网中能够高效、平稳地通行。仿真结果表明,在迭代次数达到 15 次之后,排队长度相位差和误差都趋于零,减少了交通拥堵时间。  相似文献   

时标上具有界和无界时滞的Cohen—Grossberg神经网络的全局指数稳定性     

岳远望  谷群花  陈安平 《湘南学院学报》2009,30(2)

本文在时标上研究了具有有界和分布时滞的Cohen-Grossberg神经网络,应用压缩映射原理、Lyapunov泛函方法和一些分析技巧,得到该模型平衡点的存在性和全局稳定性的充分条件.本文是首次应用时标理论将相同框架下的Cohen-Grossberg神经网络的连续系统和离散系统统一起来.  相似文献   

中国特色社会主义理论体系与中国传统文化     

陈海英 《保定学院学报》2013,(3):17-20

中国特色社会主义理论体系与中国传统文化相互联系、不可分割。一方面,中华民族优秀的传统文化是中国特色社会主义理论体系重要的思想来源,汲取中华民族传统文化之精华,中国特色社会主义理论体系得以进一步丰富和发展。另一方面,中国特色社会主义理论体系又对中国传统文化进行了马克思主义的改造,使之更具鲜活生机。  相似文献   

Independence of reaction time and response force control during isometric leg extension     

Tatsuyuki Ohtsuki ‡ 《Journal of sports sciences》2013,31(4):373-382

In this study, we examined the relative control of reaction time and force in responses of the lower limb. Fourteen female participants (age 21.2±1.0 years, height 1.62±0.05?m, body mass 54.1±6.1?kg; mean±s) were instructed to exert their maximal isometric one-leg extension force as quickly as possible in response to an auditory stimulus presented after one of 13 foreperiod durations, ranging from 0.5 to 10.0?s. In the ‘irregular condition’ each foreperiod was presented in random order, while in the ‘regular condition’ each foreperiod was repeated consecutively. A significant interactive effect of foreperiod duration and regularity on reaction time was observed (P?<?0.001 in two-way ANOVA with repeated measures). In the irregular condition the shorter foreperiod induced a longer reaction time, while in the regular condition the shorter foreperiod induced a shorter reaction time. Peak amplitude of isometric force was affected only by the regularity of foreperiod and there was a significant variation of changes in peak force across participants; nine participants were shown to significantly increase peak force for the regular condition (P?<?0.001), three to decrease it (P?<?0.05) and two showed no difference. These results indicate the independence of reaction time and response force control in the lower limb motor system. Variation of changes in peak force across participants may be due to the different attention to the bipolar nature of the task requirements such as maximal force and maximal speed.  相似文献   

Time motion analysis of 2001 and 2002 super 12 rugby     

Grant Duthie  David Pyne  Sue Hooper 《Journal of sports sciences》2013,31(5):523-530

The aim of this study was to quantify movements of Super 12 rugby players in competition because information on elite rugby players' movements is unavailable. Players were categorized into forwards [front (n = 16) and back row (n = 15)] and backs [inside (n = 9) and outside backs (n = 7)] and their movements analysed by video-based time motion analysis. Movements were classified as rest (standing, walking and jogging) and work (striding, sprinting, static exertion, jumping, lifting or tackling). The total time, number and duration of individual activities were assessed, with differences between groups evaluated using independent sample t-tests (unequal variances), while differences between halves were assessed with paired sample t-tests. Forwards had 7:47?min:s (95% confidence limits: 6:39 to 8:55?min:s, P<0.01) more time in static exertion than backs, but backs spent 0:52 (0:34 to 1:09, P = 0.01) min:s more time sprinting than forwards, and had a 0.7 (0.3 to 1.2, P = 0.01) s longer duration of each sprint. Forwards spent 7:31 (5:55 to 9:08) min:s more time in work activities (P = 0.01) and had 2.1 (1.3 to 2.8) s longer work durations (P<0.01) than backs. The results indicate frequent short duration (<4?s) work efforts followed by moderate duration (<20?s) rest for forwards, and extended (>100?s) rest duration for backs. High-intensity efforts involved static exertion for forwards (mean?±?standard deviation frequency = 80?±?17) and sprinting for backs (27?±?9). In conclusion, after nearly a decade since becoming professional, elite rugby union is still characterized by highly intense, intermittent movement patterns and marked differences in the competition demands of forwards and backs.  相似文献   

A distributional analysis of the effect of physical exercise on a choice reaction time task     

Karen Davranche  Michel Audiffren  André Denjean 《Journal of sports sciences》2013,31(3):323-329

Abstract

The aim of this study was to examine the facilitating effects of physical exercise on the reaction process. Eleven participants with specific expertise in decision-making sports performed a choice reaction time task during moderate sub-maximal exercise (90% of their ventilatory threshold power). Participants were tested at rest and while cycling. During exercise, the participants were faster, without being more variable. We suggest that the effect of exercise on cognitive performance was due to a major generalized improvement of the whole distribution of response time and, although the benefit effect was small, it was consistent throughout the entire range of reaction times.  相似文献   

Moderate-domain pulmonary oxygen uptake kinetics and endurance running performance     

A. E. Kilding  E. M. Winter  M. Fysh 《Journal of sports sciences》2013,31(9):1013-1022

Abstract

The aims of this study were to determine if the primary time constant (τ) for oxygen uptake ([Vdot]O₂) at the onset of moderate-intensity treadmill exercise is related to endurance running performance, and to establish if τ could be considered a determinant of endurance running performance. Thirty-six endurance trained male runners performed a series of laboratory tests, on separate days, to determine maximal oxygen uptake ([Vdot]O_2max), the ventilatory threshold (V_T) and running economy. In addition, runners completed six transitions from walking (4 km · h^?1) to moderate-intensity running (80% V_T) for the determination of the [Vdot]O₂ primary time constant and mean response time. During all tests, pulmonary gas-exchange was measured breath-by-breath. Endurance running performance was determined using a treadmill 5-km time-trial, after which runners were considered as combined performers (n=36) and, using a ranking system, high performers (n=10) and low performers (n=10). Relationships between τ and endurance running performance were quantified using correlation coefficients (r). Stepwise multiple regression was used to determine the primary predictor variables of endurance running performance in combined performers. Moderate correlations were observed between τ, mean response time and endurance running performance, but only for the combined performers (r=?0.55, P=0.001 and r=?0.50, P=0.002, respectively). The regression model for predicting 5-km performance did not include τ or mean response time. The velocity at [Vdot]O_2max was strongly correlated to endurance running performance in all groups (r=0.72 – 0.84, P < 0.01) and contributed substantially to the prediction of performance. In conclusion, the results suggest that despite their role in determining the oxygen deficit and having a moderate relationship with endurance running performance, neither τ nor mean response time is a primary determinant of endurance running performance.  相似文献   

基于CSSCI(2005-2012)信息安全研究文献的计量分析     

孙玉琴 《现代情报》2013,33(10):105-108

本文以中国社会科学引文索引(CSSCI)2005-2012年图书情报领域信息安全的来源文献为研究对象,从发文量、来源期刊、作者、机构、论文等学术竞争力角度进行统计和分析,得出文献发表规律和期刊、作者、机构及论文在信息安全图书情报领域的学术竞争力排名。  相似文献   

The effects of transport by pneumatic tube system on blood cell count,erythrocyte sedimentation and coagulation tests     

Fatma Emel Ko?ak  Mustafa Y?ntem  ?zlem Yücel  Mustafa ?ilo  ?zlem Gen?  Ayfer Meral 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2013,23(2):206-210

Introduction:

Today, the pneumatic tube transport system (PTS) is used frequently because of its advantages related to timing and speed. However, the impact of various types of PTS on blood components is unknown. The aim of this study was to examine the influence of PTS on the quality of routine blood cell counts, erythrocyte sedimentation, and certain blood coagulation tests.

Materials and methods:

Paired blood samples were obtained from each of 45 human volunteers and evaluated by blood cell count, erythrocyte sedimentation, and several coagulation tests, including prothrombin time (PT) and activated partial thromboplastin time (aPTT). Blood samples were divided into 2 groups: Samples from group 1 were transported to the laboratory via the PTS, and samples from group 2 were transported to the laboratory manually. Both groups were evaluated immediately by the tests listed above.

Results:

The blood sample test results from groups 1 and 2 were evaluated and compared. No statistically significant differences were observed (P = 0.069–0.977).

Conclusion:

The PTS yielded no observable effects on blood cell counts, erythrocyte sedimentation, or PT and aPTT test results. We concluded that the PTS can be used to transport blood samples and yield reliable results for blood cell counts, erythrocyte sedimentation, and several coagulation tests.  相似文献