Single-incision laparoscopic surgery: an update of current evidence

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Some scheduling problems with deteriorating jobs and learning effects

Author name used in this publication: T. C. E. Cheng2007-2008 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

Numerical solutions on fracture of piezoelectric materials by hybrid element

The cracked piezoelectric problem is observed numerically. To simulate the characteristic singularity at the crack tip, a plane piezoelectric hybrid element is derived. The new model involves displacement u, stress σo, electric displacement D and electric potential p as independent variables. The electromechanical coupling behavior of the cracked piezoelectric ceramics PZT-4 and PZT-5 is investigated. Under impermeable crack condition, the 1/√r-singularity at the crack-tip zone is exactly represented for σ and D. The efficiency of implementing the permeable crack condition is also inspected. To examine current energy release rate formulas, the path-independent integral is computed, and then a fitting formula for the energy release rate is obtained. In this paper, all the numerical results are compared with the previously reported theoretical solutions. © 2001 Elsevier Science Ltd. All rights reserved.postprin

Editorial: Technology for higher education, adult learning and human performance

This special issue is dedicated to technology-enabled approaches for improving higher education, adult learning, and human performance. Improvement of learning and human development for sustainable development has been recognized as a key strategy for individuals, institutions, and organizations to strengthen their competitive advantages. It is crucial to help adult learners and knowledge workers to improve their self-directed and life-long learning capabilities. Meanwhile, advances in technology have been increasingly enabling and facilitating learning and knowledge-related initiatives. They have largely extended learning opportunities through the provision of resource-rich and learner-centered environment, computer-based learning support, and expanded social interactions and networks. Papers in this special issue are representative of ongoing research on integration of technology with learning for innovative and sustainable development in higher education institutions and organizational and community environments.published_or_final_versio

Robustness analysis of induction motor decoupling adaption system

By using linear analysis, the robustness of an induction motor decoupling adaptation system is studied and quantitative analytical results are given. The simulation results of the system verify the analytical results.published_or_final_versio

Loss analysis of vehicle-to-grid operation

The plug-in hybrid electric vehicle (PHEV) with vehicle-to-grid (V2G) capability is becoming increasingly popular and can be expected to deploy in a large scale. According to the estimation of PHEV penetration degree and the charging characteristics, the modeling of distribution grid with extra load of PHEV charging is formulated first. The PHEVs plugged into the grid, when aggregated in a considerable number, constitute a new load. The impacts of this extra load on the grid are analyzed by power flow simulation in terms of power losses and voltage variation. Uncontrolled charging and optimal charging scenarios are compared in the 33-bus test system. The results indicate the possible problem caused by charging PHEVs and the necessity of building a new control scheme to schedule the generation and the charging profile in the grid. Thus the optimization algorithm is designed to minimize the power losses, and enhance the power quality of the grid as well. The improved model with further constraints for practical application of V2G is discussed. In this model, the ability to schedule both charging and discharging of PHEVs with V2G technology is presented. © Copyright 2011 IEEE - All Rights Reserved.published_or_final_versionThe 2010 IEEE Vehicle Power and Propulsion Conference (VPPC), Lille, France, 1-3 September 2010. In Proceedings of VPPC, 2010, p. 1-

Modeling and coordinated control for integrating electric vehicles into the power grid

This paper introduces a framework for the integration of renewable energy generation units and electric vehicle into smart grid, which takes into account the setting up of the PHEV recharging infrastructure and modern power system. The impact of recharging a large amount of PHEVs on the existing power system is estimated considering the PHEV characteristics and the driving pattern of the vehicle owners. Three scenarios for uncontrolled and controlled charging are derived to investigate the impact in terms of power quality. The simulation results show the necessity to coordinate the PHEV recharging with the power network condition. Therefore an optimal algorithm is also designed to minimize the power losses based on the hierarchical structure of the proposed framework. The aggregation of PHEVs is expected to act as a controllable load or resource. Both of the battery charging and discharging are comprised in the optimal algorithm to achieve better performance in the V2G operation. © 2011 IEEE.published_or_final_versionThe 2011 International Conference on Electrical Machines and Systems (ICEMS 2011), Beijing, China, 20-23 August 2011. In Proceedings of ICEMS, 2011, p. 1-

Integrated energy management of plug-in electric vehicles in power grid with renewables

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RFID-based hybrid Camera Tracking in Virtual Studio

This paper addresses the problem of Camera tracking in virtual studio environment. The traditional camera tracking methods can be classified into optical-based or electromechanical sensor-based. However, the electromechanical method is extensive time-consuming calibration procedures and cost too much; the optical method suffers from the error detection of references features and the chorma keying limitation in virtual studio. Therefore, in order to overcome those problems, we proposed a novel RFID-based hybrid camera tracking method in virtual studio application. Firstly, we designed a RFID passive tags based camera tracker. By using the triangular position algorithm, the accuracy could reach up to 5 centimeters. Secondly, we combined the optical based tracking method into RFID tracker with the aim to improve the orientation and position accuracy. Finally, the experiment results showed that this method could be a novel potential solution for camera tracking system in virtual studio applications. Keywords-RFID, camera tracking, chorma key, SLA

Modulating stiffness with photo-switchable supramolecular hydrogels

Stimuli-responsive hydrogels are attractive materials with many applications towards biomedicine,biology, construction, and manufacturing. Materials that can be cured or annealed rapidly at room temperature are of particular interest. In this work we develop a class of supramolecular coumarin-functionalised hydrogels formedviahost-guest mediated self-assembly with cucurbit[8]uril thatcan photo-switch to covalent gels and reversibly toggle between the two states. A principle ad-vantage of such materials is their ability to maintain a homogeneous chemical composition and crosslink density while selectively modulating stiffness with light. An investigation of the photo-reversibility of these functional materials elucidated that hydroxyethyl cellulose-coumarin based gels were soft and could only switch from a physical state to a covalent one, while hyaluronic acid-coumarin based gels were softer and could be photo-reversed back into a physical state after covalent curing.A.T. acknowledges The Winston Churchill Foundation of the United States. R.A.F. acknowledges the Cambridge Commonwealth European and International Trust. C.C.P. acknowledges the Engineering and Physical Sciences Research Council. G.W. acknowledges the Leverhulme Trus