高速公路不同养护策略的对比分析

以某高速公路长期养护为例,从结合预防性养护规划和单纯矫正性养护规划两个方面出发,建立两种长期的养护计划方案,得到两种养护方案下各路面性能指数的变化趋势.最后在高速公路的使用寿命、经济效益和路用性能三个方面,说明预防性养护在高速公路养护中的优越性,并倡导在高速公路养护中积极运用预防性养护.     

The retention of skills acquired through simulator-based training

This study examined the loss of skills across a nine month retention period following a simulator-based training programme developed to enhance the watchstanding skills of merchant marine cadets. The mitigation of decay as a function of a retraining experience was also evaluated. Two groups of merchant marine cadets were tested immediately preceding and following the programme and again nine months later. One group was given a refresher experience and tested six months into the retention interval. The evaluations were unobtrusive ratings of six watchstanding skill areas based upon performance during a 30-min simulated watchkeeping scenario. Generally, the results indicated that: (1) watchstanding skills improved following training; (2) skills declined over the nine month retention interval; and (3) refresher training was effective in terms of skill loss mitigation for some skill areas.     

徽州古民居无损检测技术与方法研究

无损检测技术是对徽州古民居结构构件检测的一种方便有效的方法.本文通过采用超声波技术对某栋徽州古民居的主要构件检测其存在的缺陷,并对无损检测方法和检测内容进行了归纳总结.通过检测得到数据,并对数据进行统计分析与归纳,提出了对徽州古民居检测的一些有益建议,为今后徽州古民居的检测、鉴定、修复提供技术参考.     

基于人体嗅觉特征的猪肉新鲜度仿生电子鼻检测技术

借鉴成人鼻腔的特殊结构及其嗅觉原理设计出具有仿生意义的气体室。根据猪肉产生的气味和传感器实验,合理选择气敏传感器。采用支持向量机(SVM)作为模式识别方法。经理化试验证明系统检测猪肉新鲜度准确率达96.45%,结果表明设计的仿生电子鼻系统检测猪肉新鲜度是可行的。     

电子鼻对不同存储时间纯牛奶的检测分析

利用电子鼻系统的气体传感器阵列对牛奶的响应曲线特征值来表示牛奶新鲜度变化,采用SPSS中逐步判别对特征进行优化,分别用最小二乘法和Bayes判别算法分析牛奶新鲜度变化情况。结果表明:逐步判别法能有效地降低数据维数,Bayes判别法和偏最小二乘法相比,把数据分布密度函数加入牛奶新鲜度识别中,提高了电子鼻对牛奶新鲜度的识别的正确率,Bayes判别法能鉴别出存储间隔12 h的商品纯牛奶新鲜度的变化。因此,利用电子鼻和Bayes判别算法是分析牛奶新鲜度的一种有效的手段。     

A novel approach to update summarization using evolutionary manifold-ranking and spectral clustering

Update summarization is a new challenge in automatic text summarization. Different from the traditional static summarization, it deals with the dynamically evolving document collections of a single topic changing over time, which aims to incrementally deliver salient and novel information to a user who has already read the previous documents. How to have a content selection and linguistic quality control in a temporal context are the two new challenges brought by update summarization. In this paper, we address a novel content selection framework based on evolutionary manifold-ranking and normalized spectral clustering. The proposed evolutionary manifold-ranking aims to capture the temporal characteristics and relay propagation of information in dynamic data stream and user need. This approach tries to keep the summary content to be important, novel and relevant to the topic. Incorporation with normalized spectral clustering is to make summary content have a high coverage for each sub-topic. Ordering sub-topics and selecting sentences are dependent on the rank score from evolutionary manifold-ranking and the proposed redundancy removal strategy with exponent decay. The evaluation results on the update summarization task of Text Analysis Conference (TAC) 2008 demonstrate that our proposed approach is competitive. In the 71 run systems, we receive three top 1 under PYRAMID metrics, ranking 13th in ROUGE-2, 15th in ROUGE-SU4 and 21st in BE.     

BAN逻辑的可靠性分析与改进

BAN逻辑的推理过程中可能引入错误的推理条件,导致不安全的协议被验证为安全的。为解决该问题,对消息的形式化描述方式进行改进,在消息含义推理规则中加上一个隐含但不能被忽略的条件,以增强验证的可靠性,通过对发送和推理的消息单元进行限定,使消息新鲜性判定规则适用于更多类型的协议安全性验证。     

玉米新鲜度快速检测方法初探

初步建立了两种定性检验玉米新鲜度的方法:愈创木酚法,以溶液开始变色所需时间及加入染色液3 min后溶液颜色的改变程度,作为检测新陈玉米的依据;盐酸对二氨基苯法,以加入染色液5 min后玉米胚部及皮层颜色的改变来推断玉米新陈.     

一类椭圆-抛物耦合方程组弱解的衰减估计

该文研究在热效应影响下半导体模型,它归结为一个非线性椭圆-抛物耦合方程组初边值问题.考虑此半导体方程瞬态解和稳态解之间的关系,通过对解的一系列估计,给出了在一定条件下瞬态解与稳态解的一个衰减估计.     

一类非线性抛物方程解的大时间性态

讨论N（N≥3）维全空间上一类非线性抛物方程解的大时间性态，利用经典的Fourier分解方法，证明了其解在L^2范数下的衰减速率为（1＋t）^-N/4，达到了和线性热传导方程解衰减率的一致性，因此在此意义下本文的结果是最优的。