基于最短路径的停车场内部诱导系统设计方法研究     

高吕和 《北京工业职业技术学院学报》2007,6(2):39-41

从图论的角度讨论了静态最优路径的算法及其复杂度,在此基础上对停车诱导功能需求进行研究,提出了停车场内部诱导系统的设计思路和方法.  相似文献   

Longitudinal study of preadolescent sport self-concept and performance: reciprocal effects and causal ordering     

Marsh HW  Gerlach E  Trautwein U  Lüdtke O  Brettschneider WD 《Child development》2007,78(6):1640-1656

Do preadolescent sport self-concepts influence subsequent sport performance? Longitudinal data (Grades 3, 4, and 6) for young boys and girls (N= 1,135; mean age = 9.67) were used to test reciprocal effects model (REM) predictions that sport self-concept is both a cause and a consequence of sport accomplishments. Controlling prior sport performance (performance-based measures and teacher assessments), prior sport self-concept had positive effects on subsequent sport performance in both Grade 4 and Grade 6 and for both boys and girls. Coupled with previous REM studies of adolescents in the academic domain, this first test for preadolescents in the sport domain supports the generalizability of REM predictions over gender, self-concept domain, preadolescent ages, and the transition from primary to secondary school.  相似文献   

Impact of Contact With Grandparents on Children's and Adolescents’ Views on the Elderly     

Allison Flamion  Pierre Missotten  Manon Marquet  Stéphane Adam 《Child development》2019,90(4):1155-1169

Stereotypes, prejudice, and discrimination against the elderly (ageism) may manifest themselves in children at an early age. However, the factors influencing this phenomenon are not well known. Using both explicit and open-ended questions, this study analyzed the influence of personal and familial parameters on the views of 1,151 seven- to sixteen-year-old Belgian children and adolescents on the elderly. Four factors were found to affect these views: gender (girls had slightly more positive views than boys), age (ageism was lowest in 10- to 12-year-old, reminiscent of other forms of stereotypes and cognitive developmental theories), grandparents’ health, and most importantly, quality of contact with grandparents (very good and good contacts correlated with more favorable feelings toward the elderly, especially in children with frequent contacts).  相似文献   

Comfort,Class and Climate Change: The Rise of Glass in Late Medieval and Early Modern Domestic Architecture     

Daniel Jütte 《Cultural and Social History》2013,10(5):621-641

ABSTRACT

In the modern world, glass windows are considered an indispensable element of the built environment. Throughout premodern times, however, glass was not universally used in European architecture. This article argues that the rise of glass in Western architecture was neither an inevitable nor a linear process, but rather a response to certain social, cultural and environmental factors that gained increasing relevance from the late medieval period onwards. In other words, glass windows are a cultural convention, reflecting some of the wide-ranging and transformative challenges that Europeans faced in the late medieval and early modern period.  相似文献   

Symptoms of common mental disorders and related stressors in Danish professional football and handball     

Özgür Kilic  Haruhito Aoki  Rasmus Haagensen  Claus Jensen  Urban Johnson  Gino M. M. J. Kerkhoffs 《European Journal of Sport Science》2017,17(10):1328-1334

The aim of the study was twofold, namely (i) to determine the prevalence of symptoms of common mental disorders (CMDs) among current and retired professional football and handball players and (ii) to explore the relationship of psychosocial stressors with the outcome measures under study. A total of 1155 players were enrolled in an observational study based on a cross-sectional design. Questionnaires based on validated scales were set up and distributed among current and retired professional football and handball players by the Danish football and handball players’ union. In professional football, the highest prevalence (4 weeks) of symptoms of CMDs was 18% and 19% for anxiety/depression among current and retired players, respectively. In professional handball, the highest prevalence (4 weeks) of symptoms of CMDs was 26% and 16% for anxiety/depression among current and retired players, respectively. For both the current and retired professional football and handball players, a higher number of severe injuries and recent adverse life events (LE) were related to the presence of symptoms of CMD. Players exposed to severe injuries and/or recent adverse LE were 20–50% times more likely to report symptoms of CMD. The results suggest that it is possible to recognize the population of professional athletes that are more likely to develop symptoms of CMD. This could create the opportunity to intervene preventively on athletes that suffered from severe injury and/or recent adverse LE that could lead to a faster and safer recovery and psychological readiness to return to play.  相似文献   

The dynamic control ratio at the equilibrium point (DCRe): introducing relative and absolute reliability scores     

Tobias Alt  Axel J. Knicker  Heiko K. Strüder 《Journal of sports sciences》2017,35(7):688-693

Analytical methods to assess thigh muscle balance need to provide reliable data to allow meaningful interpretation. However, reproducibility of the dynamic control ratio at the equilibrium point has not been evaluated yet. Therefore, the aim of this study was to compare relative and absolute reliability indices of its angle and moment values with conventional and functional hamstring–quadriceps ratios. Furthermore, effects of familiarisation and angular velocity on reproducibility were analysed. A number of 33 male volunteers participated in 3 identical test sessions. Peak moments (PMs) were determined unilaterally during maximum concentric and eccentric knee flexion (prone) and extension (supine position) at 0.53, 1.57 and 2.62 rad · s^–1. A repeated measure, ANOVA, confirmed systematic bias. Intra-class correlation coefficients and standard errors of measurement indicated relative and absolute reliability. Correlation coefficients were averaged over respective factors and tested for significant differences. All balance scores showed comparable low-to-moderate relative (<0.8–0.9) and good absolute reliability (<10%). Relative reproducibility of dynamic control equilibrium parameters augmented with increasing angular velocity, but not with familiarisation. At 2.62 rad · s^–1, high (moment: 0.906) to moderate (angle: 0.833) relative reliability scores with accordingly high absolute indices (4.9% and 6.4%) became apparent. Thus, the dynamic control equilibrium is an equivalent method for the reliable assessment of thigh muscle balance.  相似文献   

The Implications of the Concept of Lifelong Education for the Secondary School in the United Kingdom     

David Fincham  St. Peter's  Merrow Grange 《International Journal of Lifelong Education》2013,32(3):223-235

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Measuring efficiency of Tunisian schools in the presence of quasi-fixed inputs: A bootstrap data envelopment analysis approach     

Hédi Essid  Pierre Ouellette  Stéphane Vigeant 《Economics of Education Review》2010,29(4):589-596

The objective of this paper is to measure the efficiency of high schools in Tunisia. We use a statistical data envelopment analysis (DEA)-bootstrap approach with quasi-fixed inputs to estimate the precision of our measure. To do so, we developed a statistical model serving as the foundation of the data generation process (DGP). The DGP is constructed such that we can implement both smooth homogeneous and heterogeneous bootstrap methods. Bootstrap simulations were used to estimate and correct the bias, and to construct confidence intervals for the efficiency measures. The simulation results show that the efficiency measures are subject to sampling variations. The adjusted measure reveals that high schools with residence services would have to give up less than 12.1% of their resources on average to be efficient.  相似文献   

Arms control for armed uninhabited vehicles: an ethical issue     

Jürgen Altmann 《Ethics and Information Technology》2013,15(2):137-152

Arming uninhabited vehicles (UVs) is an increasing trend. Widespread deployment can bring dangers for arms-control agreements and international humanitarian law (IHL). Armed UVs can destabilise the situation between potential opponents. Smaller systems can be used for terrorism. Using a systematic definition existing international regulation of armed UVs in the fields of arms control, export control and transparency measures is reviewed; these partly include armed UVs, but leave large gaps. For preventive arms control a general prohibition of armed UVs would be best. If that is unattainable, several measures should be taken. An explicit prohibition of autonomous attack, that is without a human decision, should be added to IHL. Concerning armed UVs remotely controlled by a human soldier, recommendations differ according to type or mission. New kinds of uninhabited nuclear-weapon carriers should be banned. Space weapons should be prohibited in general. UVs smaller than 0.2–0.5 m should be banned. Bigger remotely controlled armed UVs not equipped with weapons of mass destruction should be subject to numerical limitations in various categories. For these the Treaty on Conventional Armed Forces in Europe is an important precedent.  相似文献   

Efficient reverse k-nearest neighbor estimation     

Elke Achtert  Christian B?hm  Peer Kr?ger  Peter Kunath  Alexey Pryakhin  Matthias Renz 《Informatik - Forschung und Entwicklung》2007,15(3):179-195

The reverse k-nearest neighbor (RkNN) problem, i.e. finding all objects in a data set the k-nearest neighbors of which include a specified query object, has received increasing attention recently. Many industrial and scientific applications call for solutions of the RkNN problem in arbitrary metric spaces where the data objects are not Euclidean and only a metric distance function is given for specifying object similarity. Usually, these applications need a solution for the generalized problem where the value of k is not known in advance and may change from query to query. In addition, many applications require a fast approximate answer of RkNN-queries. For these scenarios, it is important to generate a fast answer with high recall. In this paper, we propose the first approach for efficient approximative RkNN search in arbitrary metric spaces where the value of k is specified at query time. Our approach uses the advantages of existing metric index structures but proposes to use an approximation of the nearest-neighbor-distances in order to prune the search space. We show that our method scales significantly better than existing non-approximative approaches while producing an approximation of the true query result with a high recall.  相似文献