Developing an efficient algorithm for balancing mass-haul diagrams

A number of linear and integer programming techniques have been used to minimize the total cost of earthwork by considering the various factors involved in the process. Although these models often ensure a global optimum for the problem, they required sophisticated formulations and are quite involved in their setup and definition as well as being expensive computationally and therefore may be of limited use in real life. In construction practice, Mass-haul diagrams (MD) have been an essential tool for planning earthwork construction for many applications including roadwork, piping, and other linear infrastructure facilities. One of the most common heuristics that is used widely by practicing engineers in the field to balance the MD is the “shortest-haul-first” strategy. Balancing the MD using this heuristic is usually carried out either graphically on the drawing, or manually by computing values from the mass-haul diagram itself. However performing this approach graphically or manually is fairly tedious and time consuming. In addition manual and graphical approaches are prone to error. More importantly, if the project considered has a large number of stations (in the order of hundreds), then performing this balance manually becomes impractical. A robust algorithm is therefore needed that can automatically balance the MD. The research discussed here presents a formal definition of an algorithm that uses a sequential pruning technique for automatically computing balances of mass-haul diagrams. It is shown that the new algorithm is more efficient than existing integer programming techniques and computationally runs in level of complexity of O(log n) time in most cases. Thus this algorithm can handle problems with a large number of stations within a reasonable amount of time. In addition, a computer implementation and extensive computational experiments are provided. Suggestions for how this algorithm can be used in cost-based or grade-based optimization of hauling distances and quantities are discussed.     

基于自适应RBF神经网络算法的建筑结构递阶分散控制研究

针对建筑结构振动控制的递阶分散控制问题进行研究。首先,通过设置全局控制器消除子系统间的关联耦合;在此基础上,结合Lyapunov稳定性理论和RBF神经网络理论设计了仅依赖于子系统位移和速度响应反馈信息的自适应控制律,并利用差分进化（DE）算法对自适应RBF神经网络局部子控制器相关参数进行优化,建立了适用于建筑结构振动控制的自适应RBF神经网络递阶分散控制（ARBFHDC）算法。对ASCE 9层Benchmark模型进行递阶分散控制设计、优化及仿真分析。结果表明,不同地震激励下,基于ARBFHDC算法设计的递阶分散控制较传统集中控制而言有更好的控制效果,且能保障各子系统作动器处于最大功效工作状态。     

欧美石膏工业发展动态

１石膏和石膏制品生产力持续蓬勃发展美国经济在克服了９０年代初的不景气后已保持８年持续增长,带来了房地产的蓬勃发展,这给石膏工业创造了前所未有的机遇（见表１）。美国近年来由于纸面石膏板和其它建筑石膏制品的需求强劲,天然石膏矿石产量有较大增长。美国１９９８年天然石膏矿石的产量为１９００万ｔ,占全球产量１８%。全世界有９０多个国家开采天然石膏,１９９８年天然石膏矿石年生产总量至少有１．０５亿ｔ,是历史上最高的产量。根据美国１９９８年地质矿产工业调查报告,１９９８年美国天然石膏矿石产量约１９００万ｔ,产值超过１…     

对新课程背景下初中语文阅读教学策略的分析

随着新课程改革的不断深入与发展,教学手段也在不断更新,各种教学资源走进语文阅读教学已成为历史的必然。我们应充分发挥图书馆、网络等课程资源优势,优化教育技术手段,丰富教学内容,拓展教学思路,彰显课程资源在语文阅读教学中的独特魅力。     

基于自适应遗传算法的钢筋混凝土桥墩抗震设计方法

为满足钢筋混凝土桥墩抗震设计中对构件承载力和延性的要求,常需依靠设计者经验,对配筋方案进行反复调整,这就在一定程度上增加了结构设计难度,降低了工作效率。为解决这一实际问题,对传统自适应遗传算法中交叉率和变异率的计算方法进行改进,通过当前适应度值动态调整交叉率和变异率,在此基础上提出基于自适应遗传算法的钢筋混凝土桥墩结构抗震设计方法,实现对符合条件设计解的自动随机定向搜索,提高求解的收敛速度,并增强算法的鲁棒性。在对每一配筋方案的抗弯承载力和位移延性系数的计算中,又提出基于自适应遗传算法的钢筋混凝土桥墩弯矩 曲率关系的计算方法,提高求解效率。通过设计算例,可见该方法快速有效,计算过程无需人工干预,实现钢筋混凝土桥墩结构抗震设计的人工智能化。     

一种自适应AP算法的matlab实现

AP算法是Fey BJ.等人提出的一种聚类算法.与传统的K均值聚类算法相比,AP算法不需要选择初始的聚类中心点,因此,聚类结果更客观.但AP算法中相似度矩阵对角线上的偏向值需要人为设定,而这个值会影响到聚类数目;另外,当AP算法发生震荡时,算法无法自动退出震荡.为解决AP算法中的振荡问题及相似度矩阵对角线上元素值的确定问题,王开军等人提出了自适应AP算法,逐步改变偏向值p,得到不同的聚类结果,再根据聚类结果的Silhouette指标,找出最好的Silhouette指标对应的偏向值及聚类结果.当震荡发生时,逐步增加阻尼因子?值,直到算法退出震荡.使用MATLAB实现了自适应AP算法和Silhouette评价指标,为后续的研究工作打下基础.     

A practical algorithm for diagnosing control loop problems

This paper describes an algorithm for detecting and diagnosing poor performance in feedback control loops. The performance of the control loop is assessed based on criteria derived from parameters that can be estimated from superficial knowledge of the controlled process. The algorithm can distinguish between three types of control problems: oscillatory response, sluggish response, and plant failure. The method is particularly applicable to heating, ventilating, and air-conditioning (HVAC) systems where linear (PI) control law is normally used despite the existence of often quite non-linear operating characteristics. In these systems, the control performance varies as the plant is exercised across its operating range. In practice, periodical re-tuning of HVAC control loops during the yearly load cycle may be necessary in order to obtain consistent control performance. The algorithm presented in this paper can act as the basis for determining when re-tuning is necessary in addition to detecting plant failure. Potential advantages of detecting control problems in HVAC systems are energy savings, reduced maintenance costs, and improved thermal comfort conditions. The paper describes the techniques comprising the algorithm and presents results from tests carried out on a simulated air-handling unit (AHU).     

采用自适应搜索范围的多介质立体匹配算法

摄像机在水下拍摄时,成像光线经过不同介质会发生折射,空气中极线约束条件不再满足,区域匹配无法在此极线上搜索。针对此问题,提出一种采用自适应搜索范围的多介质立体匹配算法。首先对双目摄像机进行标定得到相关参数;然后针对每一像素点推导出曲线极线,并计算出与原极线的上偏差与下偏差,确定该点的最优搜索范围;再用区域算法SAD算法在每点对应的最优搜索范围中进行多行搜索并匹配。经过两组实验对比,该算法的匹配精度分别为72.4%、76.8%,而SIFT匹配算法的匹配精度分别为71.1%、74.7%。该算法的匹配精度达到了特征匹配的精度,可以用于整幅图的稠密匹配,解决了原极线搜索策略无法应用于多介质环境的问题,成功将区域匹配算法应用于多介质中的立体匹配。     

Developing an activity-based knowledge management system for contractors

Knowledge Management (KM) has become an important term in the IT industry. Knowledge management involves creating, securing, capturing, coordinating, combining, retrieving and distributing knowledge. Most know-what, know-how and experience exist only in the minds of individual participants during the construction phase of construction projects. The knowledge can be reused and shared among the engineers and experts involved who participate in projects in order to improve the construction process and reduce the time and cost of solving problems. Sharing and reusing knowledge depends on acquiring and preserving both tacit knowledge and explicit knowledge as the property of a corporation. Effectively using information and web technologies during the construction phase of a project enables knowledge to be captured and managed to the benefit of future projects. This study addresses application of knowledge management to construction projects in the construction phase and proposes a Construction Activity-Based Knowledge Management (ConABKM) concept and system for general contractors. This paper proposes the concept of integrating IDEF (Integrated DEFinition function modeling) modeling methods and provides a prototype used for designing construction knowledge management systems. The ConABKM system is then applied in a case study of a highway construction project; the results demonstrate the effectiveness of sharing knowledge in the construction phase. The combined results demonstrate that by utilizing the latest web technology, knowledge exchange and storage concepts and modes of implementation, a ConABKM system is an effective tool for all experts and engineers participating in the construction phase of a project.     

高原自适应型液压挖掘机的控制研究

介绍了通过GPS模块检测海拔高度,并通过总线将海拔高度传输到主控制器,主控制器根据存储的发动机功率与海拔高度的对应关系,自动调节液压系统的吸收功率,从而实现发动机系统和液压系统的自动匹配,避免因为负载过大导致发动机憋车、冒黑烟等高原问题。     

利用先验估计自适应加窗的准静态超声弹性成像位移估计算法

准静态弹性成像技术是基于组织压缩前和压缩后超声回波射频信号进行组织运动重构的弹性成像技术。提出了一种基于先验估计的自适应窗函数算法,在位移估计过程中,使用已估计的临近窗的时延值作为先验信息,自动调整截取压缩后射频信号段的截取窗函数,提高了互相关运算所需的压缩前和压缩后信号段之间的相关性。仿真实验结果表明,该算法不仅大大提高了成像速度,而且提高了信噪比较低时的成像质量,同时该算法具有更宽的应变通带。     

出口欧美纸面石膏板的质量控制

我国纸面石膏板发展速度迅猛,生产规模居全球第2,技术水平与国际先进水平相当。我国对纸面石膏板产品质量的要求与欧美虽已相近,但仍存在差距。通过我国国家标准与欧洲、美国标准的详细对比,找出生产企业应关注的问题,提出相关建议,以满足出口欧美的需要。     

Optimal and reference adaptive processes for the control of regional income disparities

This paper reports on studies into the controllability of the regional income disparities arising from multi-regional economic growth. The necessary condition is that no significant band of regional income disparities should result at the end of the planning period. The regional disparities among nine regions in Japan are explored using the interregional input-output technique and regional production functions. Furthermore, some potentially interesting research probes into the controllability of regional income disparities using the reference adaptive control technique are discussed.     

基于改进自适应遗传算法的混凝土搅拌站原料库存优化

为了满足建筑行业的市场需求并且节约成本,降低企业的库存费用,在市场需求不确定的条件下,通过建立基于混凝土行业的随机性(s,S)库存系统的仿真模型,使用求解多目标优化问题的遗传混合方法,设计了一种改进的自适应遗传算法,并用其优化库存控制策略.仿真结果表明:所设计的算法是一个有效的算法,能够获得较低的库存总费用,并可以更有效的解决搅拌站的库存问题.     

西欧北美等发达国家烧结墙体屋面材料的发展趋势

本文简述西欧、北美等发达国家近几年烧结墙体屋面材料的发展趋势。通过对五大类烧结墙体屋面材料产品及应用情况的介绍，表明发达国家对烧结墙体屋面材料性能的认识及应用科学、合理、到位．以期使国内对烧结墙体屋面材料产品，从生产到建筑物使用寿命终结，给出全面、正确、科学的评价。     

Development of an adaptive window-opening algorithm to predict the thermal comfort,energy use and overheating in buildings

This investigation of the window-opening data from extensive field surveys in UK office buildings demonstrates: (1) how people control the indoor environment by opening windows; (2) the cooling potential of opening windows; and (3) the use of an ‘adaptive algorithm’ for predicting window-opening behaviour for thermal simulation in ESP-r. It was found that when the window was open the mean indoor and outdoor temperatures were higher than when closed, but it was shown that nonetheless there was a useful cooling effect from opening a window. The adaptive algorithm for window-opening behaviour was then used in thermal simulation studies for some typical office designs. The thermal simulation results were in general agreement with the findings of the field surveys. The adaptive algorithm is shown to provide insights not available using non adaptive simulation methods and can assist in achieving more comfortable, lower energy buildings while avoiding overheating.     

自适应模糊PID在ALC鞍架摆渡吊机控制中的应用

针对卷扬升降加钢轮行走式ALC鞍架摆渡吊机在升降及行走定位过程中,由于惯性大、末端容易过冲、定位抖动问题,本文采用自适应模糊PID控制策略设计模糊控制器,采用MATLAB/Simulink进行仿真验证分析,然后通过MATLAB计算PID调节参数的控制量表,最终通过S7-1200以查表方式得到动态PID控制器调节参数并实时调准修改,实现对吊机的定位控制,改善其控制效果。实际应用效果表明,吊机运行平稳,定位误差小,动态响应良好。     

Developing an equitable and sustainable mobility strategy for Havana

The particular political, economic and social conditions of the state of Cuba, in the Caribbean, have created unique possibilities for the development of a sustainable transport system in its capital city, Havana. This paper reports on the outcomes of a project to identify the possibilities and priorities for a long-term strategy for equitable and sustainable mobility for Havana. This involved almost 100 participants from Cuba and the UK in the 12 months from June 2013.Overall, the study found a high degree of agreement amongst the transport policy community as to the three key transport issues facing Havana:

• •high level of unmet demand,
• •lack of available financing,
• •poor state of the transport system.

Perhaps more surprisingly, it also produced a near consensus amongst the participants that any future policy should seek to increase the quality of the public transport system by:

• •increasing levels of investment,
• •securing efficiency savings,
• •working ‘smarter’.

However, it also found that this unified view is challenged by a desire for the car market to be deregulated, which would engender a very different policy approach. A strategic choice is needed now, to determine whether Havana follows a North American-style trajectory of rapid growth in car use or a less car-dependent pathway.     

协方差矩阵重构的稳健自适应波束形成算法

针对协方差矩阵含有期望信号成分以及波束指向角失配时,传统自适应波束形成器性能严重下降的问题,提出了协方差矩阵重构的稳健自适应波束形成算法。该算法将全空域划分成若干互不重叠的区域,分别对应干扰区域与信号区域,先利用Capon波束形成器对干扰区域积分,由此构造出干扰协方差矩阵。然后,利用标准Capon波束形成器的波束域MUSIC谱估计法对信号区域积分,重构出信号协方差矩阵,以其主特征向量作为期望信号导引向量估计。由于算法重构了干扰加噪声协方差矩阵并对导引向量进行了修正,保证了自适应波束形成器的性能。理论分析和仿真实验结果表明,算法在训练数据含有期望信号成分和波束指向角度失配情况下具有良好的性能。