Feature Extraction and Recognition for Human Action Recognition

How to automatically label videos containing human motions is the task of human action recognition. Traditional human action recognition algorithms use the RGB videos as input, and it is a challenging task because of the large intra-class variations of actions, cluttered background, possible camera movement, and illumination variations. Recently, the introduction of cost-effective depth cameras provides a new possibility to address difficult issues. However, it also brings new challenges such as noisy depth maps and time alignment. In this dissertation, effective and computationally efficient feature extraction and recognition algorithms are proposed for human action recognition. At the feature extraction step, two novel spatial-temporal feature descriptors are proposed which can be combined with local feature detectors. The first proposed descriptor is the Shape and Motion Local Ternary Pattern (SMltp) descriptor which can dramatically reduced the number of features generated by dense sampling without sacrificing the accuracy. In addition, the Center-Symmetric Motion Local Ternary Pattern (CS-Mltp) descriptor is proposed, which describes the spatial and temporal gradients-like features. Both descriptors (SMltp and CS-Mltp) take advantage of the Local Binary Pattern (LBP) texture operator in terms of tolerance to illumination change, robustness in homogeneous region and computational efficiency. For better feature representation, this dissertation presents a new Dictionary Learning (DL) method to learn an overcomplete set of representative vectors (atoms) so that any input feature can be approximated by a linear combination of these atoms with minimum reconstruction error. Instead of simultaneously learning one overcomplete dictionary for all classes, we learn class-specific sub-dictionaries to increase the discrimination. In addition, the group sparsity and the geometry constraint are added to the learning process to further increase the discriminative power, so that features are well reconstructed by atoms from the same class and features from the same class with high similarity will be forced to have similar coefficients. To evaluate the proposed algorithms, three applications including single view action recognition, distributed multi-view action recognition, and RGB-D action recognition have been explored. Experimental results on benchmark datasets and comparative analyses with the state-of-the-art methods show the effectiveness and merits of the proposed algorithms

Biomechanical Analyses of Posterior Vaginal Prolapse: MR Imaging and Computer Modeling Studies.

Pelvic organ prolapse is an abnormal downward displacement and deformation of the female pelvic organs. Because it adversely affects quality of life, over 200,000 operations are performed annually for prolapse in the U.S at a cost exceeding $1 billion. Approximately 87% of those procedures involve repair of a posterior vaginal prolapse, the etiology of which is a focus of this dissertation. But, because operative failure rates can approach 30%, new insights are needed as to how and why a posterior vaginal prolapse develops in the first place so that treatment can be improved. We hypothesize that the occurrence, size and type of posterior vaginal prolapse is not explained by failure of any single structure; rather it involves failure of connective tissue supports at two and possibly up to as many as 20 anatomical sites, along with impairment of the levator ani muscle. Using in vivo magnetic resonance imaging we first visualized the detailed 3-D pelvic floor anatomy of 84 healthy women. From these we then selected images from a pelvis of average dimensions and used them to create a detailed three-dimensional interactive model of the female pelvic floor complete with 23 structures. We then developed a method to measure and quantify the geometry of prolapse in forty 3-D magnetic resonance image-based models. Two main structures relating to the development of prolapse, fascia and apical vaginal supports, were then analyzed via two case-control studies. Finally, 2- and 3-D computer-based models were developed to identify the biomechanical interactions which lead to prolapse: levator muscle and connective tissue failure, and organ competition. These methodological approaches and computer models provide new insights into the biomechanical mechanisms underlying the development of posterior vaginal prolapse. Our hope is that they will lead to more effective surgical treatment strategies for this vexing condition.PHDMechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/95942/1/jjluo_1.pd

Ambidextrous Strategy and Firm Performance: The Moderating Effects of Organizational Slack and Organizational Life Cycle

The relationship between ambidexterity and firm performance holds a prominent place in the literature. However, studies that examine the conditions under which ambidexterity leads to success are relatively scarce. Based on a sample of 226 firms in China, this study examines the moderating effects of organizational slack and organizational life cycle on the relationship between balance dimension of ambidexterity and combined dimension of ambidexterity and firm performance. The empirical results reveal that pursuing a high level of combined dimension of organizational ambidexterity is only beneficial to firms with a high level of organizational slack or firms in maturity stage, while pursuing a high level of balance dimension of organizational ambidexterity is only beneficial to firms in growth stage, but not to firms in maturity stage

Admissibility of Estimated Regression Coefficients Under Generalized Balanced Loss

There are some discussions concerning the admissibility of estimated regression coefficients under the balanced loss function in the general linear model. We study this issue for the generalized linear regression model. First, we propose a generalized weighted balance loss function for the generalized linear model. For the proposed loss function, we study sufficient and necessary conditions for the admissibility of the estimated regression coefficients in two interesting linear estimation classes.Ведуться дєякі дискусії щодо допустимості оцінєних коєфіцієнтів регресії для збалансованої функції втрат у загальній лінійній моделі. В роботі вивчається ця проблема для узагальненої лінійної моделі регресії. Так, запропоновано узагальнену зважену функцію втрати балансу для узагальненої лінійної моделі. Для вказаної функції втрат ми вивчаємо необхідні та достатні умови допустимості оцінених коефіцієнтів регресії для двох цікавих лінійних випадків оцінювання

Facile synthesis of chitosan-capped ZnS quantum dots as an eco-friendly fluorescence sensor for rapid determination of bisphenol A in water and plastic samples

This paper describes a novel eco-friendly fluorescence sensor for determination of bisphenol A (BPA) based on chitosan-capped ZnS quantum dots (QDs). By using safe and inexpensive materials, nontoxic ZnS QDs were synthesized via an environment-friendly method using chitosan as a capping agent. The as-prepared ZnS QDs exhibited characteristic absorption (absorbance edge at 310 nm) and emission (maxima at 430 nm) spectra with a relatively high fluorescence quantum yield of 11.8%. Quantitative detection of BPA was developed based on fluorescence quenching of chitosan-capped ZnS QDs with high sensitivity and selectivity. Under optimal conditions, the fluorescence response of ZnS QDs was linearly proportional to BPA concentration over a wide range from 0.50 to 300 mu g L-1 with a detection limit of 0.08 mu g L-1. Most of the potentially coexisting substances did not interfere with the BPA-induced quenching effect. The proposed analytical method for BPA was successfully applied to water and plastic real samples. The possible quenching mechanism is also discussed

The moderating effects of slack on the relationship between ambidextrous strategy and performance: evidence from high-tech firms in China

The purpose of this study is to examine the impacts of ambidexterity of exploration/exploitation on long-term performance and the moderating effects of slack resources. The methodology adopted is panel data analysis of a sample dataset of 125 high technology firms in China. The finding of this study shows that a moderating role of organizational slack between ambidexterity and long-term performance is strongly supported. The research and practical implications of this paper are: (1) Exploration and exploitation can be mutually enhancing instead of being fundamentally contradictory; (2) Slack resources moderate the relationship between ambidexterity and performance. The originality and value of the paper is that it is one of the earliest studies that empirically examine the moderating effects of slack resources on ambidexterity-performance relationship

Design of temperature insurance index and risk zonation for single-season rice in response to high-temperature and low-temperature damage: a case study of Jiangsu Province, China.

Disaster insurance is an important tool for achieving sustainable development in modern agriculture. However, in China, the design of such insurance indexes is far from sufficient. In this paper, the single-season rice in Jiangsu Province of China is taken as an example to design the high-temperature damage index in summer and the low-temperature damage index in autumn to constructtheformulacalculatingtheweatheroutputandsingle-seasonriceyieldreduction. Thedaily highest, lowest and average temperatures between 1999 and 2015 are selected as main variables for the temperature disaster index to quantitatively analyze the relationship between the temperature indexandtheyieldreductionrateofthesingle-seasonrice. Thetemperaturedisasterindexcanbeput into the relevant model to obtain the yield reduction rate of the year and determine whether to pay the indemnity. Then, the burn analysis is used to determine the insurance premium rate for all cities in Jiangsu Province under four-level deductibles, and the insurance premium rate can be used for the risk division of the Province. The research provides some insights for the design of agricultural weather insurance products, and the empirical results provide a reference for the design of similar single-season rice temperature index insurance products