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1.
Zusammenfassung. Die automatische Erkennung und Lokalisation von Objekten in digitalen Bildern ist ein wesentlicher Bestandteil vieler praktisch
relevanter Anwendungen. In diesem Artikel wird ein erscheinungsbasiertes Verfahren zur Erkennung starrer zwei- oder dreidimensionaler
Objekte vorgestellt, dem eine statistische Modellierung zugrundeliegt. Im Gegensatz zu segmentierungsbasierten Verfahren,
wie sie vor allem im Bereich der 3D-Objekterkennung eingesetzt werden, erm?glicht der erscheinungsbasierte Ansatz aufgrund
der Modellierung der Intensit?tswerte oder davon abgeleiteter lokaler Merkmale eines Bildes die Erkennung komplexer Objekte.
Die statistische Formulierung der Problemstellung bildet den mathematischen Kontext zur Bestimmung optimaler L?sungen.
Die Form der Modellierung erlaubt neben der Einzelobjekterkennung auch die Berücksichtigung von heterogenem Bildhintergrund
und Mehrobjektszenen. Die dazu ben?tigten lokalen Merkmale entstehen durch r?umlich begrenzte Transformationen des Bildes,
wie beispielsweise Gabor- oder Wavelet-Transformationen. Die statistische Modellierung beschreibt die Verteilung dieser lokalen
Merkmale anhand einer Dichtefunktion, die sich bei der Hintergrund- und Mehrobjektmodellierung als Mischungsverteilung der
Einzelobjektverteilungen ergibt. Die Aufgabenstellungen des Erlernens und Erkennens von Objekten sind damit als Parametersch?tzprobleme
formal darstellbar. Dabei werden im einen Fall die Modellparameter und im anderen Fall die Lageparameter beziehungsweise die
Klassen von Objekten gesch?tzt. Die experimentelle überprüfung des Ansatzes anhand realer Objektaufnahmen durch CCD-Kameras
zeigt seine Brauchbarkeit zur Erkennung von 2D- und 3D-Objekten bei homogenem und heterogenem Hintergrund.
Eingegangen am 5. April 2000 / Angenommen am 20. Juli 2001 相似文献
2.
Dr. Josef Leidenfrost 《Zeitschrift für Hochschulrecht, Hochschulmanagement und Hochschulpolitik: zfhr》2011,10(4):117-138
Bereits 1997 ist im damaligen Bundesministerium für Wissenschaft und Verkehr die Studierendenanwaltschaft, ?hnlich wie andere
Sonderanwaltschaften des Bundes, eingerichtet worden. Mit der Einführung von Studiengebühren an Universit?ten und Fachhochschulen
2001 wurden ihre Agenden von einer reinen Informations- auf eine ministerielle Beschwerdestelle zur Meldung und Behebung von
Missst?nden und Unzul?nglichkeiten ausgeweitet. Nach zehn Jahren T?tigkeit zeigen die Erfahrungen aus dem Alltag, dass überwiegend
informelle Individualhilfe im Vordergrund der T?tigkeit dieser Einrichtung steht. Systemm?ngel sind schwerer zu beheben, da
solche meist ressourcenbedingt oder mit einander konkurrierenden gesetzlichen Regelungen verbunden sind und es keine festgelegten
Normen des Einschreitens innerhalb der offiziellen Rechtsaufsicht des Ministeriums gibt. L?sungen sind von der Kooperationsbereitschaft
der Verantwortlichen vor Ort abh?ngig. 相似文献
3.
This paper deals with the problem of relating distance and scale by way of alternative models of perception taken from the history of science.The intuitive patterns of modern school children in evaluating the Solar System are then compared with those in the history of science. Immediate experience and intuition by children often contradict scientific understanding. The children in this study, for example, do not see the rays of the Sun as being parallel and ignore the curvature of the Earth. The authors argue that children's understanding of the rays of the Sun as not being parallel as well as their ignoring the curvature of the Earth is due to the limitation resulting from the students' `actual activity zone', and not to their insufficient knowledge. This study makes specific suggestions to broaden the scientifically based `actual activity zone' of students. We suggest that laboratory work based on historical experiments using elementary geometry – as, for example, the determination of the radiusof the Earth by Eratosthenes – promotes a scientific understanding of astronomicalmeasurements....The scale of space and time, which we customarily observe on Earth, and which is part of time, we become aware of the vastness of our universe, we are awed and humbled. But if astronomers spent all their time speculating about the immensity of the cosmos and the prodigious interval of time necessary for the evolution of the stars, their accomplishments would be few. The primary concerns of the astronomer when studying the cosmos are physical and mathematical interpretations of observations, predictions of future observations, and the development and refinement of his instruments for such interpretation and prediction. To help him in the conceptualization of his problem, astronomer may, consciously or unconsciously, visualize a small model representing the cosmic system under investigation. Using this method, we can arrive at an understanding of the relative dimensions of the system and an understanding of the time intervals involved.Shklovskii I.S. and Carl Sagan (1966)Intelligent Life in the Universe 相似文献
4.
Kinematic differences of elite and high-performance tennis players in the cross court and down the line forehand 总被引:1,自引:0,他引:1
Landlinger J Lindinger SJ Stöggl T Wagner H Müller E 《Sports biomechanics / International Society of Biomechanics in Sports》2010,9(4):280-295
This study identified and compared the full body kinematics of different skill levels in the forehand groundstroke when balls were hit cross court and down the line. Forty-three three-dimensional retroreflective marker trajectories of six elite and seven high-performance players were recorded using an eight-camera 400 Hz, Vicon motion analysis system. The six highest horizontal velocity forehands with reliable kinematics of all participants were analysed for each specific situation (a total of 156 analysed shots). Significant differences (p < 0.01) and large effect sizes were observed between elite and high-performance players in linear velocity of the shoulder (2.0 vs. 1.2 m/s), angular velocity of the pelvis (295 vs. 168 degrees/s), and angular velocity of the upper trunk (453 vs. 292 degrees/s) at impact. The elite group showed a tendency towards higher racquet velocities at impact (p < 0.05). No significant differences were found in angular displacement of the racquet, hip alignment, or shoulder alignment at the completion of the backswing; nor did angular displacement vary significantly at impact. Irrespective of the group, different shoulder, hip, and racquet angles were found at impact, depending on the situation. The results should assist coaches when striving to improve their players' forehand. 相似文献
5.
Gerda Strutzenberger Tobias Wunsch Josef Kroell Jacqueline Dastl Hermann Schwameder 《Sports biomechanics / International Society of Biomechanics in Sports》2014,13(2):97-108
Non-circular chainrings theoretically enhance cycling performance by increasing effective chainring diameter and varying crank velocity, but research has failed to consistently reproduce the benefits in cycling trials. The aim of this study was (1) to investigate the effect of different chainring shapes on sagittal knee joint moment and sagittal lower limb joint powers and (2) to investigate whether alterations are affected by cadence and workload. Fourteen elite cyclists cycled in six conditions (70, 90 and 110 rpm, each at 180 and 300 W), for 2 min each, using three chainrings of different ovalities (1.0–1.215). Kinematic data and pedal forces were collected. For most conditions, only the chainring with the highest ovality (1.215) was characterised by smaller sagittal knee joint moments, smaller relative sagittal knee joint power contribution and larger relative sagittal hip joint power contribution, which suggests a change from maximising efficiency to maximising power production. Effect sizes increased with higher cadences, but not with higher workload. This study has application for athletes, clinicians and sports equipment industry as a non-circular chainring can change joint-specific power generation and decrease knee joint moment, but certain ovality seems to be necessary to provoke this effect. 相似文献
6.
Prof. Dr. Josef Schrader 《Zeitschrift für Erziehungswissenschaft》2014,17(2):193-223
The performance of education systems is significantly influenced by the quality of teaching/learning processes. On the basis of empirical research, the programme for evidence-based educational research also contributes to improving the quality of teaching/learning processes. Hereby, new requirements for the insight of educational research as well as for the accelerated transfer of research findings into politics and practice have been formulated. Currently, the programme is strongly criticised by political and scientific stakeholders with regard to both its desirability and its feasibility. This report traces the debate on evidence-based educational reforms, systematically outlines the central topics of discussion, and views the current state of research on the contribution of empirical educational research to political and practical reforms. Particular attention is paid to the effects on teaching/learning processes. 相似文献
7.
Valery Y. Glizer Vladimir Turetsky Leonid Fridman Josef Shinar 《Journal of The Franklin Institute》2012,349(2):638-657
In order to construct the guidance strategy in a realistic nonlinear noise-corrupted interception endgame against a maneuverable target, a linearized zero-sum differential game is considered. Assuming perfect information in this game, sufficient conditions are established, which guarantee that a continuous interception strategy with memory (history-dependent) has the maximal capture zone. Two examples of such a strategy are analyzed: a modified super-twisting second-order sliding mode control and a modified integral sliding mode control. Simulation results of the original nonlinear interception endgame demonstrate that these strategies considerably reduce the chattering created by the classical game optimal bang-bang strategy without deteriorating the homing performance. 相似文献
8.
Julia Lindorfer Josef Kröll Hermann Schwameder 《European Journal of Sport Science》2019,19(2):177-185
Assessing comfort of running footwear reliably is challenging. The purpose of this study was to compare the intra-rater reliability between different assessment types, to calculate intra-individual reliability scores and to evaluate the effect of rater selection based on individual reliability scores on group level reliability. Three assessment types: ranking, Visual Analogue Scale (VAS), and Likert Scale (LS) were provided twice in six separate sessions among 30 participants, who assessed comfort of five shoes after treadmill running. Spearman's rho provided an evaluation of inter-session relative reliability and typical error as a measure of absolute reliability for each assessment type. Ranking (r?=?0.70, 95% confidence interval [CI] 0.61–0.78) yielded the highest relative reliability for overall comfort, followed by VAS (r?=?0.67, 95% CI 0.56–0.75) and LS (r?=?0.63, 95% CI 0.52–0.72), with large-scale overlaps of CIs between assessment types. The same order of assessment types was found for the percentage of reliable raters (r?≥?0.7) with 60% in ranking scale, 47% in VAS and 37% in LS. Forming subgroups corresponding to the intra-individual reliability substantially increased group level reliabilities. Based on measures of relative reliability, an extreme reduction in resolution as provided by the ranking from pairwise comparisons seems to be a valuable tool in footwear comfort assessments if assessment time is of minor importance. No preference can be provided for the two investigated rating scales. Besides the assessment type, a selection of the best raters in additional reliability checks seems to be a prerequisite for further comfort-related studies. 相似文献
9.
Theory of Mind Is Contagious: You Catch It from Your Sibs 总被引:10,自引:0,他引:10
This study investigated the relation between family size and "theory of mind." Results from an experiment with 3- and 4-year-olds showed that children from larger families were better able than children from smaller families to predict a story character's mistaken (false-belief based) action. Results from a second experiment on children with exactly 1 sibling failed to show any superiority of older over younger siblings in promoting earlier understanding of belief. The data are interpreted as suggesting that sibling interaction provides a rich "data base" for building a theory of mind, and this is discussed in relation to other studies showing that particular kinds of interaction between sibling and child, or caregiver and child, have a beneficial effect on the understanding of false belief. 相似文献
10.
Jörg Spörri Josef Kröll Hermann Schwameder Erich Müller 《European Journal of Sport Science》2018,18(7):911-919
Knowing how to enhance alpine skiing performance is essential for effective coaching. The purpose of this study was to explore the role of path length- and speed-related factors for performance enhancement, while skiing on a homogeneously set/constantly inclined giant slalom course section (average gate distance: 27?m; offset: 8?m; slope inclination: 26°). During a video-based three-dimensional kinematic field-experiment, the data of six athletes who skied a two-gate section on four different types of skis were collected. The performance parameter analysed was section time. The performance predictors analysed were centre of mass (CoM), path length and the change in specific mechanical energy per entrance speed along the analysed section. Furthermore, since the current study examined alpine skiing performance within short sections, the skier’s entrance speed was also considered. Classified as a high-performance and a low-performance group based on section time, slow and fast trials significantly differed in CoM path length, the change in specific mechanical energy per entrance speed and entrance speed. The entrance speed of all trials analysed ranged between 15.25 and 17.66?m/s. In trials with both high and low entrance speed, the change in specific mechanical energy per entrance speed was found to be more relevant for the prediction of section time than CoM path length. However, further studies should investigate whether such a prioritization can be unrestrictedly generalized to other situations, such as entrance speeds, course sets, slope inclinations and competition disciplines different to those assessed in the current study. 相似文献