Software structure evaluation based on the interaction and encapsulation of methods

Software structure is the most important factor affecting the quality of a program.The evaluation of software structure is a foundational technique for software development.However,the traditional evaluation criteria,such as "high cohesion and low coupling",are no longer appropriate for the new web applications,which are designed with a hierarchical framework.A novel approach is proposed in this paper to evaluate software quality based on the interaction and encapsulation of methods.In particular,two criteria for high quality software,the functional and hierarchical structure,are proposed to support widely used web applications.The cohesion and coupling and layer matching ratios between methods within a software package are calculated to determine whether the package is well implemented in terms of functional or hierarchical structure.This approach enables us to quantify the quality of a software system according to the structural types of its packages.Experiments were carried out on 18 versions of Struts and six open-source software packages.Our evaluation concurs with the intuition that minor upgrades,aimed at fixing bugs and adding minor functionality quickly,reduce software quality,whereas major upgrades,which normally clean up messy code and re-construct the software,improve software quality.     

单片机控制IGBT逆变式脉冲TIG焊电源的研究

本文介绍了单片机控制的ＩＧＢＴ逆变式脉冲ＴＩＧ焊电源系统的硬件结构及其焊接时序的控制和规范参数的调节方法。该系统采用接触提升引弧方式，并具有不合理规范参数的自动识别功能。     

Theoretical analysis on bending behavior of functionally graded composite beam crack-controlled by ultrahigh toughness cementitious composites

Ultrahigh toughness cementitious composites (UHTCC) obviously show strain hardening property under tensile or bending loading. The failure pattern of the UHTCC components exhibits multiple fine cracks under uniaxial tensile loading with prominent tensile strain capacity in excess of 3%, with merely 60 μm average crack width even corresponding to the ultimate tensile strain state. The approach adopted is based on the concept of functionally-graded concrete, where part of the concrete, which surrounds the main longitudinal reinforcement in a RC (reinforced concrete) member, is strategically replaced with UHTCC with excellent crack-controlling ability. Investigations on bending behavior of functionally-graded composite beam crack controlled by UHTCC has been carried out, including theo- retical analysis, experimental research on long composite beams without web reinforcement, validation and comparison between experimental and theoretical results, and analysis on crack control. In addition to improving bearing capacity, the results indicate that functionally-graded composite beams using UHTCC has been found to be very effective in preventing corrosion-induced damage compared with RC beams. Therefore, durability and service life of the structure could be enhanced. This paper discusses the development of internal force and crack propagation during loading process, and presents analysis of the internal force in different stages, moment-curvature relationship from loading to damage and calculation of mid-span deflection and ductility index. In the end, the theoretical formulae have been validated by experimental results.     

Experimental investigation and analysis on flexural performance of functionally graded composite beam crack-controlled by ultrahigh toughness cementitious composites

Based on the concept of functionally graded concrete, UHTCC (ultrahigh toughness cementitious composites) material with excellent crack-controlling ability is strategically substituted for part of the concrete, which surrounds the main longitudinal reinforcement in a reinforced concrete member. Investigations on bending behavior of such a functionally graded composite beam crack-controlled by UHTCC (abbreviated as UHTCC-FGC beam) have been carried out. After establishing a theoretical calculation model, the paper discusses the results of four-point bending experiment on long composite beams without web reinforcement, and validates the theoretical formulae through experimental results of UHTCC-FGC beams with different thicknesses of UHTCC layer. Besides improving bearing capacity and saving steel reinforcements, the results indicate that UHTCC-FGC beams can also effectively control the deformation and enhance the ductility of members. At last, the optimal thickness of UHTCC layer in UHTCC-FGC beams has been confirmed, which can not only save materials and improve mechanical performance of members, but also be very effective in preventing corrosion-induced damage and enhancing the durability of members by controlling crack width below 0.05 mm under service conditions. Supported by the Key Program of the National Natural Science Foundation of China (Grant No. 50438010) and the Research and Application Programs of Key Technologies for Major Constructions in the South-North Water Transfer Project Construction in China (Grant No. JGZXJJ2006-13)     

智能数字传送器设计

在PC机与多个单片机的串行通信基础上,从硬件和软件两方面完成了智能数字传送器的设计.智能数字传送器实现的是一台上位机(PC)机和8台下位机(单片机)的串行通信,上位机软件采用Visual Basic编程,作出十分直观的人机界面,并通过串行口将下位机的数据传送给上位机,上位机可作出应答信号,同时上位机(PC)机可向下位机(单片机)发出数据请求.系统具有对数据的修改,显示和报警等功能,目前在工业控制领域中应用非常广泛.     

Constructal design for a steam generator based on entransy dissipation extremum principle

Steam generator is optimized by applying entransy dissipation extremum principle and constructal theory and adopting analyti-cal method.The obtained results show that the optimal spacing between adjacent tubes,the mass flow rate of gas and the maximum entransy dissipation rate all depend on the dimensionless diameter of one tube,the dimensionless pressure difference number and the dimensionless length of flow channel of gas.Besides the three dimensionless groups,the optimal numbers of riser tubes and downco...     

Upward propagation of lightning-generated whistler waves into the radiation belts

Lightning-generated whistler (LGW) waves which induce energetic electron precipitation provide an important coupling between the ionosphere and radiation belts. Using the ray-tracing technique, we examine the propagation behaviour of LGW waves and show that they can travel upward into the radiation belts during higher geomagnetic activities due to the plasmapause inward compression, particularly in cases of lower wave frequencies, lower wave normal angles and azimuthal angles. Both perpendicular and parallel group velocities of LGW waves remain in relatively small values inside the plasmasphere but change rapidly to high values outside the plasmasphere. The launching latitude increases with increasing LGW wave normal angle. These results here further reveal a detailed picture on how LGW waves escape out of the plasmasphere and onto the radiation belts.     

热泵干燥机三元控制的初步研究

以更有效提高热泵干燥性能为出发点，结合湿空气的性质和压缩机的性能，提出了热泵干燥机三元控制理论。并定性分析了它的特点。     

鲁西矿预防煤炭自然发火综合技术研究与应用

鲁西矿3煤具有自然发火倾向。该文系统地介绍了一套适合鲁西煤矿生产技术条件下的预防采空区自然发火技术方案、技术参数、检测方法及其判定指标,并分析了其技术效果,对于指导煤矿今后的预防自然发火工作具有重要意义。     

离心泵性能曲线的快速拟合法

离心泵在选型时,首先就要绘制离心泵性能曲线,而传统的手工曲线绘制方法速度较慢．而且往往无法保证精度要求。使用计算机编程处理虽然能满足精度要求,但需繁杂的编程过程,对选型设计人员要求较高。为了适应计算机优化选型的要求,需要找到一个既快速又简便的方法求出离心泵性能曲线的函数表达式,从而将离心泵性能曲线转换为计算机的图形。