基于Web挖掘的关联推荐算法研究

对用户需求的分析中使用Web挖掘,其中Web个性化的实现使用的是关联规则,这一规则能够为用户提供个性化服务,并且成为Web技术的研究热点。本文以网络教学系统为案例,来对Web挖掘的关联推荐算法进行探讨。内容主要涉及到Web数据挖掘技术、关联推荐算法的思路、算法分析。     

楼顶钢塔一种独特的锚固方式及受力分析

以上海市公安局卢湾分局楼顶加设钢塔为研究对象,介绍了楼顶钢塔的设计方法.通过分析高层建筑上的钢塔在风荷载和地震作用下与下部结构的共同作用,说明在设计钢塔时必须考虑高层建筑对钢塔的影响,并提出一种新型的便于工程应用的钢塔与混凝土高层建筑的锚固方式,可供高层楼顶钢塔设计时参考.     

多馈入交互因子在多馈入交直流电网中的应用

以江苏电网实际多馈入交直流受端系统为例,对多馈入交互因子(MIIF)在实际电网规划和运行中的分析方法进行了推广应用研究。通过计算各直流逆变站间、直流与交流枢纽站之间的MIIF指标,分析各逆变站发生同时或相继换相失败的几率大小及可能存在的组合,对发现直流站换相失败的潜在风险及制定相应的预防措施具有一定的指导作用。     

Model predictive control of grid-connected PV power generation system considering optimal MPPT control of PV modules

Because of system constraints caused by the external environment and grid faults, the conventional maximum power point tracking (MPPT) and inverter control methods of a PV power generation system cannot achieve optimal power output. They can also lead to misjudgments and poor dynamic performance. To address these issues, this paper proposes a new MPPT method of PV modules based on model predictive control (MPC) and a finite control set model predictive current control (FCS-MPCC) of an inverter. Using the identification model of PV arrays, the module-based MPC controller is designed, and maximum output power is achieved by coordinating the optimal combination of spectral wavelength and module temperature. An FCS-MPCC algorithm is then designed to predict the inverter current under different voltage vectors, the optimal voltage vector is selected according to the optimal value function, and the corresponding optimal switching state is applied to power semiconductor devices of the inverter. The MPPT performance of the MPC controller and the responses of the inverter under different constraints are verified, and the steady-state and dynamic control effects of the inverter using FCS-MPCC are compared with the traditional feedforward decoupling PI control in Matlab/Simulink. The results show that MPC has better tracking performance under constraints, and the system has faster and more accurate dynamic response and flexibility than conventional PI control.     

Influence of Structure and Mineral Association of Tuyere-Level Coke on Gasification Process

Metallurgical and Materials Transactions B - The gasification properties of feed coke and tuyere coke were investigated by non-isothermal thermogravimetric method under CO2 atmosphere. The physical...     

A Novel Route for Preparation of Hollow Carbon Nanospheres Without Introducing Template

A newly developed route for the synthesis of hollow carbon nanospheres without introducing template under hydrothermal conditions was reported. Hollow carbon nanospheres with the diameter of about 100 nm were synthesized using alginate as reagent only. Many instruments were applied to characterize the morphologies and structures of carbon hollow nanospheres, such as XRD, TEM, and Raman spectroscopy. The possible formation and growth mechanism of carbon hollow spheres were discussed on the basis of the investigation of reaction influence factors, such as temperature, time, and content. The findings would be useful for the synthesis of more materials with hollow structure and for the potential use in many aspects. The loading of SnO₂ on the surface of carbon hollow spheres was processed, and its PL property was also characterized.     

Fast example-based surface texture synthesis via discrete optimization

We synthesize and animate general texture patterns over arbitrary 3D mesh surfaces. The animation is controlled by flow fields over the target mesh, and the texture can be arbitrary user input as long it satisfies the Markov-Random-Field assumptions. We achieve this by extending the texture optimization framework over 3D mesh surfaces. We propose an efficient discrete solver inspired by k-coherence search, allowing interactive flow texture animation while avoiding the blurry blending problem for the least square solver in previous work. Our technique has potential applications ranging from simulation, visualization, and special effects.     

网络市场中带宽定价与分配

本文提出一种基于微观学原理进行分布式流控制的技术，将网络模拟为竞争的市场。在这些市场中，交换机对其链路的定价基于供求关系；用户购买带宽要尽量提高他们个人的服务质量。     

基于S7-200 PLC的满箱检验机控制系统的开发

针对我国满箱检测设备大部分依赖进口、自主设备较少的弊端,设计开发了一套满箱检测系统,本文阐述了该满箱检测设备控制系统的设计思想和原则,系统结构、软硬件设计方法及其功能。     

克拉玛依砾岩油藏开发后期稳油控水综合治理研究

克拉玛依砾岩油藏大都已进入中、高含水期开发阶段,油藏油、水分布日益复杂,挖潜难度增大.针对出现的问题,以”稳油控水“为目的,在开展油藏跟踪研究和油藏精细描述基础上,在一些区块因地制宜地完善注采系统,提高配套技术水平,加强经常性的调控管理,取得了较明显的效果.并指出了目前砾岩油藏存在的主要问题及需采取的对策.