33 research outputs found
How do servant leadership and self-esteem at work shape family performance in China? : A resource-gain-development perspective
Acknowledgements This study was supported by National Natural Science Foundation of China (Grant No. 71872139), the Humanity and Social Science Foundation of Ministry of Education of China (Grant No. 18YJC630164) and The Fundamental Research Funds for the Central Universities of China.Peer reviewedPostprin
Four years of multi-modal odometry and mapping on the rail vehicles
Precise, seamless, and efficient train localization as well as long-term
railway environment monitoring is the essential property towards reliability,
availability, maintainability, and safety (RAMS) engineering for railroad
systems. Simultaneous localization and mapping (SLAM) is right at the core of
solving the two problems concurrently. In this end, we propose a
high-performance and versatile multi-modal framework in this paper, targeted
for the odometry and mapping task for various rail vehicles. Our system is
built atop an inertial-centric state estimator that tightly couples light
detection and ranging (LiDAR), visual, optionally satellite navigation and
map-based localization information with the convenience and extendibility of
loosely coupled methods. The inertial sensors IMU and wheel encoder are treated
as the primary sensor, which achieves the observations from subsystems to
constrain the accelerometer and gyroscope biases. Compared to point-only
LiDAR-inertial methods, our approach leverages more geometry information by
introducing both track plane and electric power pillars into state estimation.
The Visual-inertial subsystem also utilizes the environmental structure
information by employing both lines and points. Besides, the method is capable
of handling sensor failures by automatic reconfiguration bypassing failure
modules. Our proposed method has been extensively tested in the long-during
railway environments over four years, including general-speed, high-speed and
metro, both passenger and freight traffic are investigated. Further, we aim to
share, in an open way, the experience, problems, and successes of our group
with the robotics community so that those that work in such environments can
avoid these errors. In this view, we open source some of the datasets to
benefit the research community
A model-based circular binary segmentation algorithm for the analysis of array CGH data
<p>Abstract</p> <p>Background</p> <p>Circular Binary Segmentation (CBS) is a permutation-based algorithm for array Comparative Genomic Hybridization (aCGH) data analysis. CBS accurately segments data by detecting change-points using a maximal-<it>t </it>test; but extensive computational burden is involved for evaluating the significance of change-points using permutations. A recent implementation utilizing a hybrid method and early stopping rules (hybrid CBS) to improve the performance in speed was subsequently proposed. However, a time analysis revealed that a major portion of computation time of the hybrid CBS was still spent on permutation. In addition, what the hybrid method provides is an approximation of the significance upper bound or lower bound, not an approximation of the significance of change-points itself.</p> <p>Results</p> <p>We developed a novel model-based algorithm, extreme-value based CBS (eCBS), which limits permutations and provides robust results without loss of accuracy. Thousands of aCGH data under null hypothesis were simulated in advance based on a variety of non-normal assumptions, and the corresponding maximal-<it>t </it>distribution was modeled by the Generalized Extreme Value (GEV) distribution. The modeling results, which associate characteristics of aCGH data to the GEV parameters, constitute lookup tables (eXtreme model). Using the eXtreme model, the significance of change-points could be evaluated in a constant time complexity through a table lookup process.</p> <p>Conclusions</p> <p>A novel algorithm, eCBS, was developed in this study. The current implementation of eCBS consistently outperforms the hybrid CBS 4× to 20× in computation time without loss of accuracy. Source codes, supplementary materials, supplementary figures, and supplementary tables can be found at <url>http://ntumaps.cgm.ntu.edu.tw/eCBSsupplementary</url>.</p
The adoption of technological innovations in a B2B context and its impact on firm performance: An ethical leadership perspective
The introduction of the digital economy has opened much discussion on the various business models that challenge traditional thinking in B2B marketing. This includes technological innovation in the digital space which has brought about theoretical changes in the way marketing is applied, more so in the B2B environment where communication is essential in the alignment with various stakeholders. Several discussions on ethical leadership in the digital economy have provided some insights into addressing increased complexity in a society where markets are connected (physically) yet disconnected (proximity) and this has led marketing practices going astray. Our paper proposes the relevance of ethical leadership and its role in the application of technological innovation by arguing that technological innovation has a positive impact on firm performance and that ethical leadership plays a critical role in moderating this effect. We use a dynamic panel data system Generalized Method of Moment (GMM) approach to examine secondary data from 465 IT service companies and demonstrate that ethical leadership plays a critical role as it enables innovation through technology, and this has an impact on the firm’s performance
Reduced lignin content and altered lignin composition in the warm season forage grass Paspalum dilatatum by down-regulation of a Cinnamoyl CoA Reductase Gene
Oxidative Stress and Human Skin Connective Tissue Aging
Everyone desires healthy and beautiful-looking skin. However, as we age, our skin becomes old due to physiological changes. Reactive oxygen species (ROS) is an important pathogenic factor involved in human aging. Human skin is exposed to ROS generated from both extrinsic sources such as as ultraviolet (UV) light from the sun, and intrinsic sources such as endogenous oxidative metabolism. ROS-mediated oxidative stress damages the collagen-rich extracellular matrix (ECM), the hallmark of skin connective tissue aging. Damage to dermal collagenous ECM weakens the skin’s structural integrity and creates an aberrant tissue microenvironment that promotes age-related skin disorders, such as impaired wound healing and skin cancer development. Here, we review recent advances in our understanding of ROS/oxidative stress and skin connective tissue aging
Glycosaminoglycan-Mediated Coacervation of Tropoelastin Abolishes the Critical Concentration, Accelerates Coacervate Formation, and Facilitates Spherule Fusion: Implications for Tropoelastin Microassembly
Experimental study on sweep pattern of heavy oil reservoirs with variable speed drive based on different geological models
The heavy oil reservoirs in marine sandstone in the east of South China Sea are generally characterized by loose cementation, strong bottom water, complex interlayer distribution and low recovery degree.Therefore, the existing conventional water flooding experiments can not accurately describe the sweep law of heavy oil in single wells. Based on the geological characteristics of heavy oil reservoir in the PY oilfield, an improved physical simulation experiment of bottom horizontal plate water flooding is designed.It is applied to comprehensively study the sweep law of single well and the recovery degree of heavy oil, considering reservoir rhythm, interlayer development scale and liquid extraction time. The experimentresults are showed as following.①Interbeds developed in homogeneous rhythm and positive rhythm reservoirs transform the original bottom water drive into secondary edge water drive. The longer the well spacing of interbeds is, the stronger the inhibition of bottom water coning is. In addition, the remaining oil located in the lower transition zone, middle to small pore throat in the middle and upper zones and near the interbeds can be effectively displaced by multiple amplitude controll and fluid extraction due to gravity differentiation.In this case, the single well sweep coefficient can be enhanced. The sweep efficiency can be increased by 34.1%-54.9% after adopting 4-stage variable speed to control amplitude and extract liquid during ultra-high water cut stage. Through multiple amplitude control and liquid extraction in z1680 homogeneous rhythm reservoir and z1610 positive rhythm reservoir, the daily oil production can be increased to 2-3 times of that before liquid extraction, and the production effect is good. ②For the reverse rhythm reservoir with a range of 5-10, the permeability difference between the top and bottom is significant. Thus, it is easy to form a high permeability channel at the top. The development length of interlayer and the change of liquid extraction method have little effect on the sweep range. Through multiple amplitude control and liquid extraction, the production effect of z1640 reverse rhythm reservoir is not obvious. The research results can provide solutions for the optimization of liquid production structure and the formulation of liquid extraction methods in heavy oil reservoirs with different geological models