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Full-Text Articles in Science and Technology Studies
Finite Time Singularities For The Locally Constrained Willmore Flow Of Surfaces, James A. Mccoy, Glen Wheeler
Finite Time Singularities For The Locally Constrained Willmore Flow Of Surfaces, James A. Mccoy, Glen Wheeler
Faculty of Engineering and Information Sciences - Papers: Part A
In this paper we study the steepest descent L2-gradient flow of the functional Wλ1,λ2, which is the the sum of the Willmore energy, λ1-weighted surface area, and λ2-weighted enclosed volume, for surfaces immersed in R3. This coincides with the Helfrich functional with zero `spontaneous curvature'. Our first results are a concentration-compactness alternative and interior estimates for the flow. For initial data with small energy, we prove preservation of embeddedness, and by directly estimating the Euler-Lagrange operator from below in L2 we obtain that the maximal time of existence is finite. Combining this result …
Variational Inequality Model For Cordon-Based Congestion Pricing Under Side Constrained Stochastic User Equilibrium Conditions, Zhiyuan Liu, Qiang Meng, Shuaian Wang
Variational Inequality Model For Cordon-Based Congestion Pricing Under Side Constrained Stochastic User Equilibrium Conditions, Zhiyuan Liu, Qiang Meng, Shuaian Wang
Faculty of Engineering and Information Sciences - Papers: Part A
A major objective of the practical implemented cordon-based congestion pricing schemes is to maintain the traffic conditions within the cordon area, which is rarely considered in most of the existing studies. Thus, this paper addresses the optimal toll charge pattern that can restrict the total inbound flow of each cordon to a predetermined threshold. The toll charges on all the entry links of one cordon are required to be identical, for the ease of implementation and users' recognition. The users' route choice behaviour is assumed to follow stochastic user equilibrium (SUE) with asymmetric link travel time functions. It is shown …
Voltage Unbalance Emission Allocation Using Constrained Bus Voltage Method In Radial Distribution Networks, Devinda Perera, Philip Ciufo, Sarath Perera, Lasantha Meegahapola
Voltage Unbalance Emission Allocation Using Constrained Bus Voltage Method In Radial Distribution Networks, Devinda Perera, Philip Ciufo, Sarath Perera, Lasantha Meegahapola
Faculty of Engineering and Information Sciences - Papers: Part A
The International Electrotechnical Committee Technical Report IEC 61000-3-13 is focused on the coordination of voltage unbalance (VU) in power systems by prescribing a methodology to determine individual VU emission allocation limits to installations. This paper provides an alternative VU emission allocation process to that of the IEC Technical Report, which is based on the concept of constrained bus voltage (CBV) method. The proposed methodology can be used in relation to radial distribution networks with symmetrical distribution lines. Several application examples of the proposed methodology are presented. It is shown that the proposed methodology is superior in comparison to the VU …
Integrating Iterative Crossover Capability In Orthogonal Neighborhoods For Scheduling Resource-Constrained Projects, Reza Zamani
Integrating Iterative Crossover Capability In Orthogonal Neighborhoods For Scheduling Resource-Constrained Projects, Reza Zamani
Faculty of Engineering and Information Sciences - Papers: Part A
An effective hybrid evolutionary search method is presented which integrates a genetic algorithm with a local search. Whereas its genetic algorithm improves the solutions obtained by its local search, its local search component utilizes a synergy between two neighborhood schemes in diversifying the pool used by the genetic algorithm. Through the integration of these two searches, the crossover operators further enhance the solutions that are initially local optimal for both neighborhood schemes; and the employed local search provides fresh solutions for the pool whenever needed. The joint endeavor of its local search mechanism and its genetic algorithm component has made …
Mip-Based Stochastic Security-Constrained Daily Hydrothermal Generation Scheduling, J Aghaei, M Karami, K M. Muttaqi, A Ahmadi, H A. Shayanfar
Mip-Based Stochastic Security-Constrained Daily Hydrothermal Generation Scheduling, J Aghaei, M Karami, K M. Muttaqi, A Ahmadi, H A. Shayanfar
Faculty of Engineering and Information Sciences - Papers: Part A
This paper presents the application of a mixedinteger programming (MIP) approach for solving stochastic security-constrained daily hydrothermal generation scheduling (SCDHGS). Power system uncertainties including generating units and branch contingencies and load uncertainty are explicitly considered in the stochastic programming of SCDHGS. The roulette wheel mechanism and lattice Monte Carlo simulation (LMCS) are first employed for random scenario generation wherein the stochastic SCDHGS procedure is converted into its respective deterministic equivalents (scenarios). Then, the generating units are scheduled through MIP over the set of deterministic scenarios for the purpose of minimizing the cost of supplying energy and ancillary services over the …
Voltage Security Constrained Reactive Power Optimization Incorporating Wind Generation, L G. Meegahapola, E Vittal, A Keane, D Flynn
Voltage Security Constrained Reactive Power Optimization Incorporating Wind Generation, L G. Meegahapola, E Vittal, A Keane, D Flynn
Faculty of Engineering and Information Sciences - Papers: Part A
This paper presents a comparative analysis between conventional optimal power flow (OPF) and voltage constrained OPF strategies with wind generation. The study has been performed using the New England 39 bus system with 12 doublyfed induction generator (DFIG) based wind farms installed across the network. A voltage security assessment is carried out to determine the critical wind farms for voltage stability enhancement. The power losses and individual wind farm reactive power generation have been compared with and without voltage stability constraints imposed on the OPF simulation. It is shown that voltage constrained OPF leads to much greater active power losses …
Hippocampal Shape Classification Using Redundancy Constrained Feature Selection, Luping Zhou, Lei Wang, Chunhua Shen, Nick Barnes
Hippocampal Shape Classification Using Redundancy Constrained Feature Selection, Luping Zhou, Lei Wang, Chunhua Shen, Nick Barnes
Faculty of Engineering and Information Sciences - Papers: Part A
Landmark-based 3D hippocampal shape classification involves high-dimensional descriptor space, many noisy and redundant features, and a very small number of training samples. Feature selection becomes critical in this situation, because it not only improves classification performance, but also identifies the regions that contribute more to shape discrimination. This work identifies the drawbacks of SVM-RFE, and proposes a novel class-separability-based feature selection approach to overcome them. We formulate feature selection as a constrained integer optimization and develop a new algorithm to efficiently and optimally solve this problem. Theoretical analysis and experimental study on both synthetic data and real hippocampus data demonstrate …
A General Projection Framwork For Constrained Smoothing, E Mammen, J S. Marron, B A. Turlach, M P. Wand
A General Projection Framwork For Constrained Smoothing, E Mammen, J S. Marron, B A. Turlach, M P. Wand
Faculty of Engineering and Information Sciences - Papers: Part A
There are a wide array of smoothing methods available for finding structure in data. A general framework is developed which shows that many of these can be viewed as a projection of the data, with respect to appropriate norms. The underlying vector space is an unusually large product space, which allows inclusion of a wide range of smoothers in our setup (including many methods not typically considered to be projections). We give several applications of this simple geometric interpretation of smoothing. A major payoff is the natural and computationally frugal incorporation of constraints. Our point of view also motivates new …