A NAM Representation Method for Data Compression of Binary Images

A representation method using the non-symmetry and anti-packing model (NAM) for data compression of binary images is presented.The NAM representation algorithm is compared with the popular linear quadtree and run length encoding algorithms.Theoretical and experimental results show that the algorithm has a higher compression ratio for both lossy and lossless cases of binary images and better reconstructed quality for the lossy case.     

Development of NiTiNb in-situ composite with high damping capacity and high yield strength

The shape memory alloys are well known to exhibit high damping capacity in martensite state,but possess low yield strength because of the reorientation or de-twining of the martensite variants.The high damping mechanism of shape memory alloys was introduced.The NiTiNb alloys with high yield strength and high damping capacity were designed and prepared.The microstructure evolution,martensitic transformation behavior,damping capacity and mechanical properties of series NiTiNb alloys were investigated.In vi...     

SP 3D在硫磺回收项目中的定制与开发应用

采用三维工厂设计系统SP 3D对某硫磺回收装置项目开展布置设计的过程中,通过定制、扩展和二次开发等工作,达到完善设计标准数据库和更加智能化工作的目的。举例介绍了管架数据库扩展、图面定制二次开发和地下管线交叉点报告等工作,展示了专业知识与专业软件的深入结合,可以提升设计效率和降低设计错误,从而提高了工程设计质量。     

Influence of Node Dynamics on Cluster Global Time Continuity

The cluster global time can change in wireless sensor networks due to leader re-elections and node disabilities between two successive synchronizations,which will affect temporal relationships.This paper analyzes cluster global time continuity,using global time change models for the node dynamics.The results prove that defining the global time using the cluster average time(AGT) is more stable than defining it using a single node’s local time(SGT).With normally distributed clock-parameter assumptions,the AGT change bounds are at most 70.7% of those for the SGT’s.The impacts of the initial phase and frequency skew distributions on the global time continuity are also investigated to show that the initial phase variations may strongly influence the continuity.Simulations show that the AGT is more stable with less disabled nodes or larger clusters.The appropriate cluster size is 20-40 when there are less than 15 disabled nodes.     

Global view of Hopf bifurcations of a van der Pol oscillator with delayed state feedback

This paper presents both analytical and numerical studies on the global view of Hopf bifurcations of a van der Pol oscillator with delayed state feedback. Based on a detailed analysis of the stability switches of the trivial equilibrium of the system, the stability charts are given in a parameter space consisting of the time delay and the feedback gains. The center manifold reduction and the normal form method are used to study Hopf bifurcations with respect to the time delay. To gain an insight into the pe...     

Bifurcation and chaos of the bladed overhang rotor system with squeeze film dampers

To study the nonlinear dynamic behavior of the bladed overhang rotor system with squeeze film damper (SFD),a blade-overhang rotor-SFD model is formulated using the lumped mass method and the Lagrange approach.The cavitated short bearing model is employed to describe the nonlinear oil force of the SFD.To reduce the scale of the nonlinear coupling system,a set of orthogonal transformations is employed to decouple the one nodal diameter equations of blades,which are coupled with the dynamical equations of the ...     

大学新生入学适应状况研究——组织新成员社会适应理论的校园探索

考察了组织新成员社会适应理论对于大学新生校园生活适应过程的适用性。142名北京大学2009级本科新生在入学3个月时报告了他们的适应指标和心理健康水平;在入学6个月时,他们再次被邀请报告他们的心理健康水平、第一学期的成绩与社会活动表现。结果表明：新生的入学适应水平能够有效预测入学3个月和6个月时的一般生活满意度、入学3个...     

Some It Formulas with Respect to Mixed Fractional Brownian Motion and Brownian Motion

Some It formulas with respect to mixed Fractional Brownian motion and Brownian motion were given in this paper.These extended the It formula for the fractional Wick It Skorohod integral with respect to Fractional Brownian motion,meanwhile extended the It formula for It Skorohod integral with respect to Brownian motion.Taylor's formula is applied to prove our conclusion in this article.     

欧洲焊接标准体系在不锈钢车体制造中的应用分析

在目前世界各国的城市交通体系中,轨道车辆扮演的觉得愈加重要。由于社会对轨道车辆安全性的特殊要求,在轨道车辆制造规程中的每一个环节都起着非常重要的作用。特别是焊接环节。本文主要探讨在不锈钢地铁车体设计和制造过程中,出口的不锈钢车辆的企业怎样利用欧洲焊接标准体系来生产达到欧洲制造标准要求的车辆,在车辆制造焊接各个环节企业的管理。