678 research outputs found
Resilience enhancement for urban distribution network via risk-based emergency response plan amendment for ice disasters
No full textHigh-impact low-probability (HILP) events, such as ice disasters, result in large losses of critical loads (CLs) in the urban distribution network (UDN). Thus, emergency response plans are usually made against various HILP events to improve the UDN resilience. However, these emergency plans are usually made under incomplete and imperfect information; thus, the execution of these plans may not be effective and even risky under the real situation. Therefore, in this paper, a multi-stage UDN resilience enhancement framework is proposed for tackling this challenge. At the first stage, the distribution system operator (DSO) forms typical failure scenarios based on historical data of damage to electric components under ice disasters. Under each scenario, the DSO designs a response plan to minimize the CLs' loss and associated costs. Thanks to the updated information on the ice disaster, at the second stage, DSO makes a risk assessment on the planned emergency response. If the risk is unacceptable for any period of the ice disaster, at the third stage, DSO amends the response plan to alleviate the "second-order " impacts on CLs, distribution lines, and distributed generations (DGs). Finally, simulations on the modified IEEE-69 system, including 10 CLs and some DGs, show that the proposed framework can effectively reduce second-order impacts due to both the ice disaster and its impact on the execution of originally planned emergency response
Negative and zero thermal expansion in alpha-(Cu2-xZnx)V2O7 solid solutions
No full textNegative or zero thermal expansion (NTE or ZTE) of materials is intriguing for controllable thermal expansion. We report a series of orthorhombic alpha-Cu2-xZnxV2O7 (x = 0, 0.1, 0.2), in which the volumetric coefficients of thermal expansion are successfully tuned from -10.19 * 10-6 K-1 to -1.58 * 10-6 K-1 in the temperature range of 100-475 K by increasing the content of Zn2+. It has been revealed that the transverse vibrations of oxygen bonded with vanadium are dominant in the contraction of the bc plane, leading to the overall volume NTE in alpha-Cu2V2O7. The introduction of Zn2+ densifies the crystal structure, which is presumed to suppress the space of transverse vibrations and results in the ZTE in alpha-Cu1.8Zn0.2V2O7. This work presents an effective method to realize ZTE in anisotropic framework systems
Co-Assembly of Heparin and Polypeptide Hybrid Nanoparticles for Biomimetic Delivery and Anti-Thrombus Therapy
No full textFunctional architectures based on self-assembly of bio-inspired dipeptides: Structure modulation and its photoelectronic applications
No full textGetting inspiration from nature and further developing functional architectures provides an effective way to design innovative materials and systems. Among bio-inspired materials, dipeptides and its self-assembled architectures with functionalities have recently been the subject of intensive studies. However, there is still a great challenge to explore its applications likely due to the lack of effective adaptation of their self-assembled structures as well as a lack of understanding of the self-assembly mechanisms. In this context, taking diphenylalanine (FF, a core recognition motif for molecular self-assembly of the Alzheimer's p-amyloid polypeptides) as a model of bio-inspired dipeptides, recent strategies on modulation of dipeptide-based architectures were introduced with regard to both covalent (architectures modulation by coupling functional groups) and non-covalent ways (controlled architectures by different assembly pathways). Then, applications are highlighted in some newly emerging fields of innovative photoelectronic devices and materials, such as artificial photosynthetic systems for renewable solar energy storage and renewable optical waveguiding materials for optoelectronic devices. At last, the challenges and future perspectives of these bio-inspired dipeptides are also addressed. (C) 2015 Elsevier B.V. All rights reserved
A matching approach to business services and software services
No full textRecent studies have shown that service-oriented architecture (SOA) has the potential to revive enterprise legacy systems (Cai et al., 2011; Gaševic and Hatala, 2010; De Castro et al., 2011; Chengjun, 2008; Elgedawy, 2009; Tian et al., 2007; Chen et al., 2009; Zhang et al., 2006; Sindhgatta and Ponnalagu, 2008; Khadka, 2011), making their continued service in the corporate world viable. In the process of reengineering legacy systems to service-oriented architecture, some software services extracted in legacy system can be reused to implement business services in target systems. In order to achieve efficient reuse to software services, a matching approach is proposed to extract the software services related to specified business services, where service semantics and structure similarity measures are integrated to evaluate the similarity degree between business service and software services. Experiments indicate that the approach can efficiently map business services to relevant software services, and then legacy systems can be reused as much as possible
Isotropic Zero Thermal Expansion and Local Vibrational Dynamics in (Sc,Fe)F3
No full textScandium fluoride (ScF3) exhibits a pronounced negative thermal expansion (NTE), which can be suppressed and ultimately transformed into an isotropic zero thermal expansion (ZTE) by partially substituting Sc with Fe in (Sc0.8Fe0.2)F3 (Fe20). The latter displays a rather small coefficient of thermal expansion of −0.17 × 10−6/K from 300 to 700 K. Synchrotron X-ray and neutron pair distribution functions confirm that the Sc/ Fe−F bond has positive thermal expansion (PTE). Local vibrational dynamics based on extended X-ray absorption fine structure indicates a decreased anisotropy of relative vibration in the Sc/Fe−F bond. Combined analysis proposes a delicate balance between the counteracting effects of the chemical bond PTE and NTE from transverse vibration. The present study extends the scope of isotropic ZTE compounds and, more significantly, provides a complete local vibrational dynamics to shed light on the ZTE mechanism in chemically tailored NTE compounds
Shear-slip behaviour of prefabricated composite shear stud connectors in composite bridges
No full textThis paper has investigated the shear-slip behaviour of an innovative prefabricated composite shear stud (PCSS) connector and its application in the prefabricated steel–concrete composite bridges. A series of push-out tests are carried out on a total of 12 specimens, including 6 PCSS specimens and 6 conventional shear stud (CSS) specimens. Further comparison has been carried out between the test result and the data available from the literature. Based on the test, a high-resolution finite element (FE) analysis has been performed to reveal the load transfer mechanism of the PCSS connector at the component-level. After that, an advanced FE model has been established and validated by a full-scale test of the prefabricated composite bridge using the PCSS. With the FE model, the load-slip behaviour and slip distribution are investigated in details. The result highlights the enhanced shear capacity and ductility of the PCSS specimens compared with the CSS specimens, as well as the feasibility of PCSS connectors in composite bridges. Meanwhile, it is further revealed by the detailed investigation that the enhancement could be attributed to the lateral constraint on the concrete by the vertical steel plate in the PCSS. Besides, it is also found that the load-slip behaviour of composite bridges using the PCSS is influenced by the cracking at the seam between deck blocks. Consequently, abrupt changes can be found in the load-slip curve once the cracking occurs, which differs from the traditional composite bridges.Accepted Author ManuscriptSteel & Composite Structure
Advances in the Application of Image Processing Fruit Grading
No full textInternational audienceIn the perspective of actual production, the paper presents the advances in the application of image processing fruit grading from several aspects, such as processing precision and processing speed of image processing technology. Furthermore, the different algorithms about detecting size, shape, color and defects are combined effectively to reduce the complexity of each algorithm and achieve a balance between the processing precision and processing speed are keys to automatic apple grading
Various Discriminatory Features for Eye Detection
No full textFive types of discriminatory features are derived using a Discriminatory Feature Extraction (DFE) method from five different sources: the grayscale image, the YCbCr color image, the 2D Haar wavelet transformed image, the Histograms of Oriented Gradients (HOG), and the Local Binary Patterns (LBP). The DFE method, which applies a new criterion vector defined on two measure vectors, is able to derive multiple discriminatory features in a whitened Principal Component Analysis (PCA) space for two-class problems. As the popular discriminant analysis method derives only one feature for a two-class problem, the DFE method improves upon the discriminant analysis method for two class problems, where one feature usually is not enough for achieving good classification performance. The effectiveness of the DFE method as well as the five types of discriminatory features is evaluated for the eye detection problem. Experiments using the Face Recognition Grand Challenge (FRGC) version 2 database show that the DFE method is able to improve the discriminatory power of the five types of discriminatory features for eye detection. In particular, the experimental results reveal that the discriminatory HOG features achieve the best eye detection performance, followed in order by the discriminatory YCbCr color features, the discriminatory 2D Haar features, the discriminatory grayscale features, and the discriminatory LBP features. © Springer-Verlag Berlin Heidelberg 2012
Fast eye detection using different color spaces
No full textThis paper presents a fast method for detecting the center of the eye in color face images using different color spaces. Specifically, this method consists of three stages. First, a color face image is transformed from the RGB color space to the YUV color space to extract the U color component image, whose binary image is utilized by projection functions to roughly locate the eye boundaries. Second, the center of the eye is identified within the eye boundaries through two different approaches: one approach converts the RGB image to a gray scale image and pinpoints the center of the eye with the lowest intensity value, while the other approach transforms the color image from the RGB color space to the HSV color space and singles out the center of the eye with the largest intensity variation compared with its 8-neighbors in the H color component image. Note that the better result due to these two approaches is chosen as the center of the eye. Finally, the center of the eye is adjusted based on the prior knowledge of anthropometry for further improving the accuracy of eye detection. Experiments using 974 randomly chosen Face Recognition Grand Challenge (FRGC) images show the feasibility of our eye detection method. In particular, the eye detection rate of both eye centers being accurately detected is 95.4%. © 2011 IEEE
- …
