MQM:一种用于Web服务查找的多维QoS模型

随着Web的发展,可供选择的功能相同或相似的Web服务越来越多,因此有必要为用户提供一种高效的基于服务质量(QoS)的Web服务查询机制.然而现有的Web服务QoS管理模型并不能很好的支持如动态查询等查询需求,其查询性能也有待提高.鉴于此,本文提出一种新的Web服务管理模型——多维QoS模型(MQM:Multi-dimensional QoS Model),并介绍了该模型的创建方法和相关算法.MQM通过多维模型来管理QoS数据,提供查询和OLAP操作.实验证明MQM能够使用户能更准确和快速的按QoS查询现有服务,很好地解决了传统查询方法无法确定查询条件、无法动态改变查询区间、查询性能不高等问题,进而改善了用户体验.     

基于多维特征向量及ANN技术的色彩传递算法

灰度图像色彩传递可以实现对灰度图像的自动上色处理。分析了目前色彩传递的经典算法——Welsh算法，指出了该算法存在的两大不足之处，提出了一种包含高频纹理信息的向量式像素点描述方式，并结合最近邻域搜索算法（ANN），提出了一种新的色彩传递算法,弥补了传统算法的不足，使灰度图像的彩色化效果有了较大改进。     

A multi-dimensional solver for the steady Euler equations

In this paper a numerical algorithm for the solution of the multi-dimensional steady Euler equations in conservative and non-conservative form is presented. Most existing standard and multi-dimensional schemes use flux balances with assumed constant distribution of variables along each cell edge, which interfaces two grid cells. This assumption is believed to be one of the main reasons for the limited advantage gained from multi-dimensional high order discretisations compared to standard one-dimensional ones. The present algorithm is based on the optimisation of polynomials describing the distribution of flow variables in grid cells, where only polynomials that satisfy the Euler equations in the entire grid cell can be selected. The global solution is achieved if all polynomials and by that the flow variables are continuous along edges interfacing neighbouring grid cells. A discrete approximation of a given spatial order is converged if the deviation between polynomial distributions of adjacent grid cells along the interfacing edge of the cells is minimal. Results from the present scheme between first and fifth order spatial accuracy are compared to standard first and second order Roe computations for simple test cases demonstrating the gain in accuracy for a number of sub- and supersonic flow problems.     

Probabilistic Seismic Hazard Assessment for Bridgetown-Barbados,Employing Subduction Interface Characteristic Earthquakes

A new probabilistic seismic hazard analysis was performed for the city of Bridgetown, Barbados, West Indies. Hazard computations have been performed using the standard Cornell-McGuire approach based on the definition of appropriate seismogenic sources and expected maximum magnitudes, the authors take into consideration the possibility of large subduction interface earthquakes of magnitude 8.0-9.0 beneath the Barbados accretionary prism via application of a characteristic model and slip rates. The analysis has been conducted using a standard logic-tree approach. Uniform hazard spectra have been calculated for the 5% of critical damping and the horizontal component of ground motion for rock site conditions setting 5 return periods （95, 475, 975, 2,475 and 4,975 years） and spectral accelerations for 34 structural periods ranging from 0 to 3 s. The disaggregation results suggest that the magnitude-distance pair that dominates the hazard yields M 7.4 and 8.6 and a distance of 42.5 km in the Interface Subduction Zone beneath Barbados for the 475 and 975 years RP （return period）, respectively. An event with an M 8.0 at a distance of 107.5 km in the Intraplate Subduction Zone is the second scenario that dominates the hazard for both 475 and 975 years RP.     

Pulse extraction and displacement response evaluation for long-period ground motions

Long-period ground motions with directivity and/or path effects are often characterised by the presence of velocity and acceleration pulses in the lowermost frequency range. An objective of this article is to present a discrete-time signal processing method for isolating these pulses. In this method, the velocity and the acceleration pulses are identified by applying a low-pass discrete-time filter H_lp (ω) at a suitable cut-off frequency f _c to the Fourier transforms of the original velocity and acceleration ground motion time histories, respectively. Another objective of this article is to present a mathematical expression for evaluating the linear displacement response of a single degree-of-freedom (SDF) system by simultaneous application of two frequency modulators, H_lp (ω) and H_u (ω), to the original ground excitation. By using only the pulse component of the ground motion as the excitation force, it is shown that the displacement response of the SDF system with natural period exceeding a certain value referred to as the cut-off period T _c is quite comparable with that due to the original ground excitation. Also, for ground motions that contain multiple-period pulses, it is shown that the displacement response spectrum of the SDF system exhibits multiple peaks at different natural system periods T _n.     

轴向等距分布式外科手术多维力传感器设计

为了精确采集手术机器人的多维作用力,提出了一种轴向等距分布式多维力测量传感器及其解耦方案,根据三条光纤布拉格光栅(FBG)的受力情况通过最小二乘法进行初步解耦,鉴于多种外部因素所造成的传感器输入与输出数据的非线性关系,基于前馈神经网络实现传感器的最终解耦。实验结果表明,所提出的传感器测量精度较高,解耦方法切实有效,能够准确测量手术过程中工具杆的受力情况。     

A new control algorithm to protect nonlinear base‐isolated structures against earthquakes

Currently, nonlinear base isolation systems are widely used in the construction of earthquake resistant structures. However, they are found to be vulnerable in near‐fault regions as a result of long‐period pulses that may exist in near‐source ground motions. Various control strategies including passive, active and semi‐active control systems have been studied in order to handle this issue. In this study, a semi‐active control algorithm based on the different performance levels anticipated from an isolated building during different levels of ground shaking was developed. The proposed performance‐based algorithm is based on a modified version of the well‐known semi‐active skyhook control algorithm. A series of analyses were performed on the base‐isolated benchmark building, suggested by the American Society of Civil Engineers committee, subject to seven pairs of scaled ground‐motion records. The results proved that the new control algorithm is successful in improving structural and nonstructural performance of isolated buildings under near‐fault earthquakes. Copyright © 2012 John Wiley & Sons, Ltd.     

多维跨界互动式教学模式创新的实践探讨

教学方式的选择,直接影响知识在传递更新与积累拔高过程中的损益效果,并进而影响行业技术水平与理论研究成果的提高与突破。结合"2018西部九校+《规划师》杂志社(9+1)建筑类本科联合毕业设计暨‘中晟杯’设计竞赛"教学实践活动,探讨跨地域、跨学科、跨空间、跨领域、跨群体多维跨界的互动式教学实践,以拓宽学生视野,实现多方机构互惠共赢,推动师生之间的教学相长,落实教育资源共享共用理念,推进互动式教学模式的创新。     

Experimental Study on Difference in Reflood Core Heat Transfer among CCTF,FLECHT-SET and Predicted with FLECHT Correlation

It has been reported that the core heat transfer coefficients measured in the CCTF tests, which were conducted under the conditions expected to appear during the refiooding period in a PWR, can not be predicted well with the FLECHT correlation, which has been used in the safety evaluation. In order to investigate the reason for this, a CCTF test was conducted under the typical FLECHT-SET experimental conditions. Investigating results from both tests, the following has been clarified:

The FLECHT correlation can not describe the heat transfer for the refiooding situations with the initial Accumulator injection period, which is expected to appear in a PWR, and gives much lower values than the measured. The core heat transfer in the FLECHT-SET is similar to that in the CCTF, and they are well predicted with the Murao-Sugimoto correlation. When there is some core radial power distribution, which strongly affects the heat transfer in a large vScale core, the heat transfer coefficients in the CCTF can be well predicted with taking account of this effect in addition to the Murao-Sugimoto correlation.     

Harmonic analysis of GaN-HEMTs at different temperatures and frequencies using Volterra power series

In this study, the detailed harmonic analysis of GaN high electron mobility transistor (HEMT) at different temperatures and frequencies is presented. Volterra power series and multi-dimensional Laplace transform are used as a method. The Volterra power series is also solved up to third degree, and the small signal transfer functions of kernels (H₁, H₂ and H₃) are obtained. The relationship between drain inductance (L_d), gate–source voltage (V_gs), impedance (Z_L) and the effect of frequency (F_r) to the output gain is identified. Besides, the nonlinear gains of H₁, H₂ and H₃ kernels of the GaN-HEMT are obtained. The inverse relationship between the output gains of H₁, H₂ and H₃ kernels are derived. An unsuitable situation has also been identified for sub-carrier inter-modulation systems. In addition, an asymmetric structure is also obtained between the output gain of H₂ and side-band frequencies. The effects of other parameters are carried out for the output gain.