垂直网站及其信息服务模式

The paper introduces vertical portals and their information service modes,analyzes the inevitability of their emergence and development, and finally gives some suggestions as to how to do a good job in providing information service through vertical portals.     

基于搜索引擎的用户网络信息资源组织

网络环境下,面向用户网络信息资源的组织在信息资源建设和利用过程中具有重要的作用.文章主要介绍了网络信息资源组织的特点,以及用户怎样利用搜索引擎方式去满足自己的信息需求.     

Feature Solution in the Process of Parameterizing Port Model

Aimed at attaining to an integrated and effective pattern to guide the port design process, this paper pats forward a new conception of feature solution, which is based on the parameterized feature modeling. With this solution, the overall port pre-design process can be conducted in a virtual pattern. Moreover, to evaluate the advantages of the new design pattern, an application of port system has been involved in this paper; and in the process of application a computational fluid dynamic analysis is concerned. An ideal effect of cleanness, high efficiency and high precision has been achieved.     

Study of CNG/diesel dual fuel engine's emissions by means of RBF neural network

Great efforts have been made to resolve the serious environmental pollution and inevitable declining of energy resources. A review of Chinese fuel reserves and engine technology showed that compressed natural gas (CNG)/diesel dual fuel engine (DFE) was one of the best solutions for the above problems at present. In order to study and improve the emission performance of CNG/diesel DFE, an emission model for DFE based on radial basis function (RBF) neural network was developed which was a black-box input-output training data model not require priori knowledge. The RBF centers and the connected weights could be selected automatically according to the distribution of the training data in input-output space and the given approximating error. Studies showed that the predicted results accorded well with the experimental data over a large range of operating conditions from low load to high load. The developed emissions model based on the RBF neural network could be used to successfully predict and optimize the emissions performance of DFE. And the effect of the DFE main performance parameters, such as rotation speed, load, pilot quantity and injection timing, were also predicted by means of this model. In resume, an emission prediction model for CNG/diesel DFE based on RBF neural network was built for analyzing the effect of the main performance parameters on the CO, NOx emissions of DFE. The predicted results agreed quite well with the traditional emissions model, which indicated that the model had certain application value, although it still has some limitations, because of its high dependence on the quantity of the experimental sample data.     

基于用户信息需求的元搜索引擎的构建

针对当前网络搜索引擎未能较多地关注用户需求、查全率与查准率不高、彼此间不兼容的缺陷,提出建立基于用户需求的元搜索引擎,并分析其基本原理,给出其基本结构,讨论其运行机制和关键技术。指出基于用户需求的元搜索引擎可使网络信息资源在一定程度上结构化,实现网络信息资源的自组织,提高网络信息检索的查全率和查准率.     

基于分类目录的元搜索引擎模型的提出与实现

本文首先给出了搜索引擎的定义、工作机制及分类 ,并指出了目前搜索引擎的不足 ,针对这些不足提出了几点改进意见 ,实现了一种基于分类目录的元搜索引擎。最后对该搜索引擎进行了评估和展望     

从社会性标签中进行语义关系抽取——一种元数据生成方法

标签形式的社会性语义越来越占据主导地位,使元数据界在这种新形式的信息内容表达和检索方面面临机遇和挑战。其中,主要的挑战是与标签相关的语境信息的缺失。以Flickr标签为例,对如何利用社会性语义资源来丰富主题元数据进行了实验。实验过程包含4个步骤：收集Flickr标签样本;通过共有信息计算标签间的同现情况;通过Google检索结果来追踪标签对的语境信息;用自然语言处理和机器学习技术来抽取标签间的语义关系。本实验能够利用Google搜索结果构建语境库,并且以自然语言处理和机器学习算法对这些语句进行处理。这种新方法对于赋予标签对以一定语义关系有相当高的准确率。也探讨该方法在利用社会性语义丰富的主题元数据方面的意义。     

自动分类在搜索引擎性能优化中的应用

本文论述了自动分类在搜索引擎中的作用,介绍了网页自动分类实现的方法,分析了网络自动分类系统的实例,最后展望了自动分类在搜索引擎中的应用前景.     

启发式教学在内燃机原理课程教学中的应用

＂内燃机原理＂是热能与动力工程专业的一门专业主干课。本文基于启发式教学的本质与特征,结合＂内燃机原理＂课程特点以及教学组多年来的教学改革与实践经验,分别从教学内容、教学方法以及教学实践等方面提出了提高教学质量的若干思路与方法。指出该课程教学重点是改进教学方式、合理组织教学过程,注重理论与实践相结合,切实提高学生的独立思考与实践能力。     

因特网信息检索模式及其优化设想

本文论述了因特网环境下基于超文本的浏览模式和基于搜索引擎的检索模式两种信息检索模式的产生、原理和缺陷。并根据其现存问题及网络资源自身的特点,着重就建立专业性的网络资源指引库、受控语言的引入和使用、“智能代理”的应用、跟踪记录检索路径和内容提示以及使用语义——文献双层数据结构五点优化设想进行了简要分析。