Feasibility study on buoyancy-weight ratios of a submerged floating tunnel prototype subjected to hydrodynamic loads

The research progress of a novel traffic solution,a submerged floating tunnel（SFT）,is reviewed in terms of a study approach and loading scenario.Among existing publications,the buoyancy-weight ratio（BWR） is usually predefined.However,BWR is a critical structural parameter that tremendously affects the dynamic behaviour of not only the tunnel tube itself but also the cable system.In the context of a SFT prototype（SFTP） project in Qiandao Lake（Zhejiang Province,China）,the importance of BWR is illustrated by finite element analysis and subsequently,an optimized BWR is proposed within a reasonable range in the present study.In the numerical model,structural damping is identified to be of importance.Rayleigh damping and the corresponding Rayleigh coefficients are attained through a sensitivity study,which shows that the adopted damping ratios are fairly suitable for SFTP.Lastly,the human sense of security is considered by quantifying the comfort index,which helps further optimize BWR in the SFTP structural parameter design.

Weighted Time-Variant Slide Fuzzy Time-Series Models for Short-Term Load Forecasting

Short-term load forecast plays an important role in the day-to-day operation and scheduling of generating units. Season and temperature are the most important factors that affect the load change, but random factors such as big sport events or popular TV shows can change demand consumption in particular hours, which will lead to sudden load changes. A weighted time-variant slide fuzzy time-series model (WTVS) for short-term load forecasting is proposed to improve forecasting accuracy. The WTVS model is divided into three parts, including the data preprocessing, the trend training and the load forecasting. In the data preprocessing phase, the impact of random factors will be weakened by smoothing the historical data. In the trend training and load forecasting phase, the seasonal factor and the weighted historical data are introduced into the Time-variant Slide Fuzzy Time-series Models (TVS) for short-term load forecasting. The WTVS model is tested on the load of the National Electric Power Company in Jordan. Results show that the proposed WTVS model achieves a significant improvement in load forecasting accuracy as compared to TVS models.

Load Balancing Algorithm for Cache Cluster

By the load definition of cluster, the request is regarded as granularity to compute load and implement the load balancing in cache cluster. First, the processing power of cache-node is studied from four aspects: network bandwidth, memory capacity, disk access rate and CPU usage. Then, the weighted load of cache-node is customized. Based on this, a load-balancing algorithm that can be applied to the cache cluster is proposed. Finally, Polygraph is used as a benchmarking tool to test the cache cluster possessing the load-balancing algorithm and the cache cluster with cache array routing protocol respectively. The results show the load-balancing algorithm can improve the performance of the cache cluster.

WEIGHTED SOLUTION OF SMALL-DEFLECTION BUCKLING EQUATION OF THIN SHELL

Based on small-deflection buckling equation, a weighted solution for critical load is presented. Usually, it is very difficult to solve the equation for general problems, especially those with complicated boundary conditions, Axisymmetric problem was studied as an example. Influencing factors were found from the equation and averaged as the buckling load by introducing weights. To determine those weights, some special known results were applied. This method solves general complicated problems by using the solutions of special simple problems, simplifies the solving procedure and expands the scope of solvable problem. Compared with numerical solution, it also has fine precision.

Effects of fundamental structure parameters on dynamic responses of submerged floating tunnel under hydrodynamic loads

This paper investigates the effects of structure parameters on dynamic responses of submerged floating tunnel （SFT） under hydrodynamic loads. The structure parameters includes buoyancy-weight ratio （BWR）, stiffness coefficients of the cable systems, tunnel net buoyancy and tunnel length. First, the importance of structural damp in relation to the dynamic responses of SPT is demonstrated and the mechanism of structural damp effect is discussed. Thereafter, the fundamental structure parameters are investigated through the analysis of SFT dynamic responses under hydrodynamic loads. The results indicate that the BWR of SFT is a key structure parameter. When BWR is 1.2, there is a remarkable trend change in the vertical dynamic response of SFT under hydrodynamic loads. The results also indicate that the ratio of the tunnel net buoyancy to the cable stiffness coefficient is not a characteristic factor affecting the dynamic responses of SFT under hydrodynamic loads.

Weight Management of Young Women with Down Syndrome: <i>C-ICAN</i>Meal Plan

Primary care physicians are in a unique position to provide a holistic and individualized care to their patients with Down Syndrome. These patients share common medical problems with general population;however, they often are medically complex and present with cardiac, orthopedic, and endocrine challenges such as overweight-obesity and related comorbidities that occur with more frequency in this unique population. The prevention of overweight-obesity is an important public health issue for both the general population and for the population of individuals with Down Syndrome. If abnormal weight gain is treated early and effectively many secondary comorbidities can be prevented or ameliorated. This case report discusses the impact of implementing a Consistent Individualized Carbohydrate controlled Anti-inflammatory Nutrition plan (C-ICAN) as part of the treatment plan for a young woman with Down Syndrome (DS). The C-ICAN meal plan is a low glycemic load meal plan with 30% to 35% calories from fat, 20% to 25% calories from protein, 40% to 45% calories from carbohydrate, and goal of 25 gm fiber per day. The C-ICAN meal plan combines the Mediterranean diet because of its well-established anti-inflammatory, and cardiovascular benefits, with a high protein and low glycemic-load meal plan to improve satiety and glycemic control. In this case the patient and her caregivers adjusted to a structured meal pattern well, weight balance resulted, and mealtime stress was reduced.

基于时变权重模型预测的双向DC-DC优化控制方法

双向DC-DC变换器是电动汽车的关键电压变换部件,提高其动态负载下的响应速度与鲁棒性对电动汽车低压供电系统有重要意义。提出一种基于模糊时变权重的MPC(model predictive control)控制方法。基于状态空间平均法建立变换器动态模型。基于MPC原理搭建变换器MPC模型,实现对电压的跟踪控制;在分析权重对动态负载下电压跟踪性能的影响的基础上,设计权重模糊调节器,实现权重的在线调节。基于HM-cSPACE搭建实验平台验证所提方法的准确性。在Matlab/Simulink环境下与PI控制和传统MPC控制进行对比,结果表明:在负载变化时采用时变权重MPC控制的变换器有更好的动态性能和鲁棒性,超调量降低26.1%。该方法对提高双向DC-DC变换器动态负载下的优化控制具有重要意义。

Efficient Dynamic Economic Load Dispatch Using Parallel Process of Enhanced Optimization Approach

In Dynamic Economic Load Dispatch (DELD), optimization and evolution computation become a major part with the strategy for solving the issues. From various algorithms Differential Evolution (DE) and Particle Swarm Optimization (PSO) algorithms are used to encode in a vector form and in sharing information and both approaches are based on the master-apprentice mechanism for the Dual Evolution Strategy. In order to overcome the challenges like the clustering of PSO, optimization problems and maximum and minimum searching, a new approach is developed with the improvement of searching and efficient process. In this paper, an Enhanced Hybrid Differential Evolution and Particle Swarm Optimization (EHDE-PSO) is proposed with Dynamic Sigmoid Weight using parallel procedures. A hybrid form of the proposed approach combines the optimizing algorithm of Enhanced PSO with the Differential Evolution (DE) for the improvement of computation using parallel process. The implementation and the parallel process are analyzed and discussed to gather relevant data to show the performance enhancement which is better than the existing algorithm.

考虑容重比的车辆配载优化综述

零担货运具有货物品种多样,体积和重量变化大的特征,基于容重比的车辆配载优化可同时提升车辆载重率和容积利用率,进而大幅度降低物流成本,在交通和物流行业具有重要的研究价值。首先,介绍了考虑容重比的车辆配载优化问题及其数学规划模型,再针对求解该问题的算法进行分析归纳予以综述。目前,求解算法大多集中于精确算法和启发式算法以及智能优化算法。随着人工智能的发展,还可以考虑机器学习思想在相关方面的应用。最后对于考虑容重比的车辆配载优化在当前形势下面临的新挑战,提出几个未来在研究该问题时可以考虑研讨方向,期望能为考虑容重比的车辆配载优化研究提供参考。

基于装卸顺序的中型机多航段协同配载优化

多航段、多经停的航空货运航班,飞行过程中需要合理控制飞机的重心(CG)位置,保持平衡状态,中转站装卸操作过程中需要避免额外装卸操作,减少时间和劳力浪费,因此,研究多航段航班的协同配载问题具有重要现实意义。根据航空器自身特点与集装器(ULD)装卸顺序,结合各航段飞机装载平衡与过站机场ULD装卸操作要求,通过协调分配各航段ULD和散货位置,建立了中型机联程航班多目标整数线性规划模型。模型考虑了ULD和散货的质量、体积及与舱位的匹配限制,航空器限重、舱位限重、舱位及区域累积限重、上下舱联合限重和CG位置的平衡限制,以及前后航段ULD和散货的连接性约束。根据造成中间机场额外装卸操作的2种原因,基于装卸顺序,提出装卸优化模型,通过ULD的舱内平移,优化了CG,减少了装卸次数。以B757-200F机型为例,在两装一卸、一装两卸和两装两卸3种场景下,采用商用求解器Gurobi,分别针对3种不同目标函数组合进行求解和分析对比。实验表明:所提模型可以有效协调过站货物的额外装卸次数,优化前后两航段的CG位置。

基于VMD-改进最优加权法的短期负荷变权组合预测策略

为提升短期电力负荷预测精度,提出了一种变权组合预测策略。首先,为了降低负荷数据的不平稳度,使用变分模态分解(variational mode decomposition,VMD)将负荷数据分解成了高频、低频、残差3种特征模态分量。其次,充分计及负荷数据的时序特点,参考指数加权法原理设计自适应误差重要性量化函数,并结合组合模型在时间窗口内的历史负荷数据的均方预测误差设计改进最优加权法的目标函数和约束条件,以完成子模型的准确变权。最后,针对波动较强的高频分量选定极端梯度提升(XGBoost)和卷积神经网络-长短期记忆(CNN-LSTM)模型并使用改进最优加权法进行组合预测、低频分量使用多元线性回归(MLR)模型预测、残差分量使用LSTM模型预测,叠加各模态分量的预测结果,实现了短期负荷数据的准确预测。实验结果表明,使用策略组合模型的平均绝对百分比误差为4.18%。与使用传统组合策略的组合模型相比,平均绝对百分比预测误差平均降低了0.87%。

计及源-荷不确定性的屋顶集成光储系统容量配置

利用建筑屋顶光伏发电是提高终端能源消费结构中可再生能源占比和降低用户能源成本的有效措施。针对建筑楼宇的屋顶集成光储(RIPVS)系统容量配置问题,提出计及源-荷不确定性的容量优化配置决策方法。在对光伏出力和负荷进行源-荷不确定性建模的基础上,以气象因素构建源-荷耦合气象特征集,运用K-均值聚类方法实现源-荷场景集削减,以刻画源-荷不确定性;建立以RIPVS系统全寿命周期成本最小化为目标的多场景容量优化配置模型,通过求解该模型获得反映备选方案技术经济的多维度指标,利用改进熵权法最终确定最优方案。以某商业楼宇的RIPVS系统容量配置为例,验证了所提决策方法的有效性。

基于博弈论与改进CRITIC-AHP的配电网线路脆弱性评估

针对现有配电网线路脆弱性评估指标单一的问题,从配电网结构、运行状态和故障影响等三个方面出发,全面考虑网络拓扑结构、负荷类型、潮流分布、设备参数和线路故障等影响因素,提出了改进的线路介数、改进的线路度数、线路电压稳定性和线路潮流熵等脆弱性评估指标。为解决权重分配过程中出现的权重偏好问题,提出基于博弈论与改进CRITIC-AHP组合赋权法的综合评价模型。最后,通过在IEEE33节点系统上进行仿真,验证了所提方法的有效性。

基于差分进化算法的减速器齿轮参数优化设计

根据上海道路循环工况,利用载荷的随机连续性和20CrMnMo材料的低载强化特性进行减速器齿轮有限寿命的轻量化设计。基于线性损伤理论,分别计算编制载荷谱和连续载荷谱在低载强化效应下的疲劳损伤,将疲劳损伤约束在一定范围内为选取条件,以齿轮体积最小为优化目标,建立了齿轮有限寿命的轻量化优化模型,通过差分进化算法求解得到优化后的齿轮参数。实验结果表明,设计的模型可快速准确优化齿轮参数,在采用连续载荷谱和考虑低载强化效应时,优化的齿轮参数最小。优化的模型可移植性好,可直接迁移到其他变速系统零件的轻量化设计。

基于回溯树的动态容重比平衡货物配载研究

针对零担物流货物装载率低下的现状,研究货物有限条件下多车多品种货物的货物配载问题,构建以最小化车辆数量、最大化车辆总容积和总载重量利用率为目标的多目标数学模型,考虑到单件货物的装载会对车辆以及车辆集合的剩余容积和剩余载重量产生影响,设计基于动态容重比平衡法和装载回溯树的启发式算法,对算法结果进行非支配排序,得到帕累托解集,计算帕累托解集内每个解的拥挤距离,并选择拥挤距离最大的解为最优装载方案。以算法计算精度和时间复杂度为标准,将所设计算法与NSGA-2、CPLEX算法进行对比分析,算例结果验证了算法的有效性。

基于智慧路灯云平台的动态权重负载均衡算法

大规模路灯向云平台发送数据会导致服务器在高并发情况下的各节点出现负载失衡、引起通信故障。针对该问题,文中基于微服务提出了一种基于智慧路灯云平台的动态权重负载均衡算法。该算法在初始化时根据各个服务器的硬件性能计算出各自的权重系数及各节点的初始权值,并在请求过程中结合CPU(Central Processing Unit)和网络带宽的空闲率动态地调节服务器权重,实现负载的优化。通过设定最低阈值与计算出的剩余负载率进行比较,将到达负载上限的服务器权值置为0,防止服务器出现过载情况。测试结果表明,在实验环境下,文中算法相比于最小连接数算法和平滑加权轮询算法具有更优的负载均衡效果,相比于动态权重算法,平均响应时间和实际并发连接数也有所提升。

基于混合特征的农电负荷智能优化识别方法研究

对农电负荷进行非侵入式负荷辨识,有助于掌握用户负荷信息,合理开展电网经济调度,达到降低网损、调节峰谷差等目的。本文针对农电多类型负荷同时运行时的负荷特征,以混合特征和智能优化算法为基础,提出1种基于频率加权因子遗传算法(Frequency Weighting Factor Genetic Algorithm,FWF-GA)的异种负荷同时识别方法。该方法以时域信号的有功功率、无功功率以及频域信号的幅频特性建立混合特征模型,以有功功率和无功功率构建同时识别的优化模型,并以混合特征模型构建遗传算法异种负荷同时识别的适应度函数。通过农村居民5种用电设备的负荷识别对所提方法进行验证。采用本文所提方法对5000组混合负荷进行识别,识别结果表明5种电器的单个识别准确率以及整体识别的平均准确率均在90%以上;采用3种不同适应度函数的识别方法对8组混合负荷进行识别,识别结果表明本文所提方法的识别效率最高。实例分析的结果表明,基于FWF-GA的异种负荷同时识别方法具有较好的识别效率和精度。

基于密度峰值聚类和改进LWLR的短期电力负荷预测

短期电力负荷数据具有复杂性和不确定性等特征,这些特征往往会对数据的预测结果产生不可控制的影响。使用传统的聚类方法对短期电力负荷数据进行聚类分析时,预测结果会因电力负荷的不确定性等特点产生偏差。此外,考虑到全局回归预测方法在建模阶段无法对不同部分的数据采用不同的建模方式,限制了对于不同分布区域或不同特征子集的自适应性能力的问题。文中采用K近邻和加权相似性的密度峰值聚类算法对短期电力负荷数据进行特征分类,并提出一种利用K近邻的局部加权线性回归模型对短期电力负荷进行预测。该模型的优点在于避免了欧氏距离对簇类中心选取的影响,降低了全局数据对局部数据的负面影响,避免了簇类划分的集中效应,提高了模型的泛化能力。通过与模糊C均值聚类和传统的全局回归预测方法对比,本文提出的模型对于真实电力数据的预测效果更加优越。

云计算环境中自适应负载均衡设计与实现

设计了一种新的可分配的加权轮询负载均衡方法,结合云计算技术通过高效的调度,平衡位于不同的地区、不同用户传入的负载请求,通过使用分布式数据源的数据,可以有效利用云资源和提高任务处理时间。实验证明该方法与轮询调度方法、加权最小连方法相比能够更加高效。

基于落锤-弹簧碰撞系统的燃气爆炸载荷模拟加载方法研究

为避免燃气爆炸实验带来的危险,可通过载荷模拟装置产生燃气爆炸载荷替代传统燃气爆炸实验。本文设计开发了一种基于落锤-弹簧碰撞系统的燃气爆炸载荷模拟装置及加载方法,通过一维弹性碰撞理论建立起了系统响应过程的运动方程,并推导得到了载荷与时间之间的函数关系;根据压力时间函数特征以正弦函数和指数函数乘积形式对燃气爆炸实测压力时程曲线进行拟合,建立了模拟燃气爆炸载荷落锤-弹簧碰撞系统参数快速计算方法;该装置及实验方法表明调整阻尼器的阻尼系数、弹簧的刚度和落锤的质量,可获得与燃气爆炸载荷特征相符的压力加载作用时长和载荷峰值。落锤-弹簧碰撞系统可以对燃气爆炸载荷进行多工况多场景的有效模拟。