Bionic Design and Simulation Analysis of Energy-Efficient and Vibration-Damping Walking Mechanism

节能减振步行机构的仿生设计及仿真分析

张锐¹,庞浩¹,何远^1,2,韩佃雷¹,文立阁³,江磊⁴,李建桥¹

（1. 吉林大学 工程仿生教育部重点实验室,长春 130022;

2. 长春长光睿视光电技术有限责任公司,长春 130102;

3. 吉林大学 机械与航天工程学院,长春 130022;

4. 中国北方车辆研究所,北京 100072）

摘要：非洲鸵鸟能以60 km/h的速度持续奔跑30分钟,其后肢结构具有优良的节能、减振性能。为实现腿式机器人高效节能、缓冲减振的腿部机构的设计,根据鸵鸟跗骨间关节的被动回弹特性以及腿部的输出刚度可变特性,结合鸵鸟后肢结构的比例和尺寸,设计出了仿生刚-柔复合腿式机器人单腿结构。并且利用ADAMS软件模拟了仿生机械腿的运动。通过运动仿真分析,研究了内弹簧刚度系数在一定范围内的变化对机身质心垂直加速度以及电机功耗的影响,获得最佳的内弹簧刚度系数为200 N/mm,并进一步验证了内外弹簧机制能够有效地降低机械腿的能耗。仿真结果表明,采用内外弹簧机制能够有效降低电机约72.49%能耗。

关键词：工程仿生;仿生机械腿;被动回弹特性;刚-柔复合结构;节能减振

     

手指静脉图像感兴趣区域提取研究综述

近年全球的疫情促使生物识别技术进一步发展,指静脉识别作为第二代生物识别技术因其具有极高的安全性等优点而被应用于各个领域。指静脉图像感兴趣区域提取作为指静脉识别系统至关重要的一部分,是识别系统性能与适应不同应用场景的保证。分别介绍了商用指静脉识别产品与科研用指静脉采集设备,对其公开数据集进行了整理与分析;重点论述了指静脉图像预处理中感兴趣区域提取的主要工作,对各个步骤的代表性方法进行了深入梳理与分析,并对指静脉特征提取与匹配认证进行了概述;最后对其今后的发展与应用进行了总结与展望。     

NASA系列雪参数反演算法在单像元内的时间序列验证与分析

NASA系列算法(Chang,NASA96和Foster算法)是被动微波遥感反演雪深、雪水当量的简单、实用的经验算法,并经过了很多学者大范围的算法验证和改进。为了进一步评价NASA系列算法在东北地区的时空适用性,于长春净月潭区域选定了一个以农田和森林为主的10km×10km被动微波遥感混合像元,在时间上连续观测整个干雪期(2014年12月至次年2月)的积雪参数和气象数据,结合FY3B卫星搭载的微波成像仪(MWRI)亮温数据,对NASA系列算法精度进行了评价分析。结果表明:对于雪深的反演,Chang算法和NASA 96算法前期反演效果较好,后期随着时间的推进高估雪深的趋势愈加明显。由于考虑了森林覆盖率的影响,NASA 96算法的反演精度更高。两种算法最大高估值分别是24.46和14.62cm,这是因为期间雪性质不断变化,尤其是雪粒径不断增大的缘故。Foster算法也严重高估了雪水当量,可能是由于积雪类型的分类系统未必适合于东北地区的积雪特征。本文的积雪连续观测数据为认识东北地区的积雪特性奠定了基础,对算法的时间序列验证与分析为雪参数反演算法的进一步改进提供了可靠依据。     

集群环境中微服务容器资源特征分析及优化

在集群环境中部署微服务已经成为微服务部署的重要方式.由于不同种类服务对于CPU、内存、磁盘等资源的需求不同,导致集群中的节点产生资源碎片、出现资源消耗倾斜.如何提高集群资源利用率、降低集群能耗,成为继保障服务级别协议(service level agreement, SLA)之后的重大挑战.本文以阿里巴巴集团2021年发布的近两万个微服务的详细跟踪为数据样本,从容器资源使用情况、节点部署特征和资源消耗偏好等多个维度出发,分析其集群资源消耗特征,发现集群中出现了资源消耗倾斜的情况.通过进一步分析节点中容器部署情况发现容器资源分配不合理加剧了这一现象.基于此我们提出了一种使用深度双Q网络的模型,依据上游服务资源需求的实时变化,对容器资源分配进行优化.对比实验结果表明该方法可以在保证服务SLA的情况下有效提高容器资源利用率,改善节点资源消耗倾斜的情况.     

Factors affecting forestland owners' allocation of non-forested land to pine plantation for bioenergy in Virginia

Studies have shown that woody bioenergy can have potential economic, social, and environmental benefits. One of the ways to meet the growing biomass demand for woody bioenergy is by allocating currently non-forested land for growing feedstocks such as pine. Towards this end, we conducted a survey on 900 randomly selected private forestland owners in Virginia and asked what proportion of their non-forested land they would allocate for loblolly pine at given bid prices. We then used recursive partitioning based Tobit regression to analyze data. Our results suggest that the experience of having supplied wood for chip-n-saw mills in the past five years, large land holding, prior experience with state/federal financial/technical support programs, among other factors, lead to smaller proportion of non-forested land being allocated for pine. However, a higher price offer, stronger preference for producing non-timber forest products such as evergreen boughs and grapevine, and lesser dependence on working the land for annual income lead to larger proportion of non-forested land being allocate for pine. Our results could assist policy makers in developing and improving land use and energy policies, certification programs, and extension and outreach services. Our contribution also includes the use of threshold analyses to delineate tipping points in variables associated with different response rates and showing the different effect of variables in terms of how they affect the supply of biomass and the supply of land for bioenergy purposes.     

酵母菌的磁性载体固定化及处理精炼大豆油废水

采用发酵性丝孢酵母菌处理精炼大豆油废水,首先利用海藻酸钠和所制备的Fe₃O₄磁性载体分别对酵母菌进行固定化,然后分别用酵母菌、磁性载体、海藻酸钠固定化酵母菌和磁性载体固定化酵母菌来处理精炼大豆油废水。对处理结果进行对比分析,结果显示：4种物质中,磁性载体固定化酵母菌对精炼大豆油废水处理36 h时效果最佳。pH值6.0比较适合磁性载体固定化酵母菌的生长,处理36 h的废水中的酵母菌的OD₆₀₀值为19.78。通过研究不同pH值和不同接种量条件对磁性载体固定化酵母菌处理精炼大豆油废水的情况,得到处理废水的较优条件：废水pH值6.0,酵母菌接种量10%,处理时间36 h,此条件下废水的化学需氧量(COD)值为2 430 mg/L。     

A novel multi-parameter support vector machine for image classification

The support vector machine (SVM) classification algorithm has received increasing attention in recent years in remote sensing for land-cover classification. However, it is well known that the performance of the SVM is sensitive to the choice of parameter settings. The traditional single optimized parameter SVM (SOP-SVM) attempts to identify globally optimized parameters for multi-class land-cover classification. In this article, a novel multi-parameter SVM (MP-SVM) algorithm is proposed for image classification. It divides the training set into several subsets, which are subsequently combined. Based on these combinations, sub-classifiers are constructed using their own optimum parameters, providing votes for each pixel with which to construct the final output. The SOP-SVM and MP-SVM were tested on three pilot study sites with very high, high, and low levels of landscape complexity within the Sanjiang Plain – a typical inland wetland and freshwater ecosystem in northeast China. A high overall accuracy of 82.19% with kappa coefficient (κ) of 0.80 was achieved by the MP-SVM in the very high-complexity landscape, statistically significantly different (z-value = 3.77) from the overall accuracy of 72.50% and κ of 0.69 produced by the traditional SOP-SVM. Besides, for the moderate-complexity landscape a significant increase in accuracy was achieved (z-value = 2.44), with overall accuracy of 84.03% and κ of 0.80 compared with an overall accuracy 76.05% and κ of 0.71 for the SOP-SVM. However, for the low-complexity landscape the MP-SVM was not significantly different from the SOP-SVM (z-value = 0.80). Thus, the results suggest that the MP-SVM method is promising for application to very high and high levels of landscape complexity, differentiating complex land-cover classes that are spectrally mixed, such as marsh, bare land, and meadow.     

A New Method of Simulating Bright Temperature of Snow Cover based on Snow Grain Size Evolution Process

This research used HUT model, DMRT model and MEMLS model to simulate interactions(absorption and extinction) between snow grainsfor different wave bands (18.7 GHz and 36.5 GHz) of microwave which were used for radiative transfer model. Obtaining the snow grain size is always a difficulty. So this research used Jordan91 snow grain size evolution model to evolve snow grain size which was regarded as input parameter of radiative transfer model, and used measured data to simulate spaceborne brightness temperature for 18.7 GHz horizontal polarization and 36.5 GHz horizontal polarization in a mixed pixel. The results showed that the bias of simulation brightness temperature using extinction coefficient of HUT model, DMRT model and MEMLS model for 18.7 GHz horizontal polarization were -3.6 K、-1.8 K and -0.7 K respectively, and for 36.5 GHz horizontal polarization were 4.0 K、10.4 K and 14.4 K respectively. For 18.7 GHz horizontal polarization and 36.5 GHz horizontal polarization, the bright temperature simulation based on effective snow grain size shows a good linear relationship with the brightness temperature simulation basedon snow grain size evolution process. Therefore, the method based on the snow grain size evolution process is a suitable method for obtaining the snow grain size parameter in the radiative transfer model.     

A Comparative Study on the Biosorption of Cd2+ onto Paecilomyces lilacinus XLA and Mucoromycote sp. XLC

The filamentous fungi XLA and XLC isolated from Cd-contaminated soil were identified morphologically and phylogenetically as Paecilomyces lilacinus and Mucoromycote sp., respectively. The minimum inhibitory concentrations (MICs) of Cd²⁺, Co²⁺, Cu²⁺, Zn²⁺, Cr³⁺ and Cr⁶⁺ in minimum mineral (MM) medium agar plates were 29,786, 2945, 9425, 5080, 1785 and 204 mg·L⁻¹ for XLA and 11,240, 884, 9100, 2540, 3060 and 51 mg·L⁻¹ for XLC, respectively. Favorable biosorption conditions for adsorption of Cd²⁺ by the tested fungi were investigated. Efficient performances of the biosorbents were described using Langmuir isotherm model, and the predicted maximum biosorption capacities for Cd²⁺ were 77.61 mg·g⁻¹ of XLA and 79.67 mg·g⁻¹of XLC. Experiments on desorption potential of biosorbents validated their efficacy at a large scale. Results showed that XLA obtained a desorption rate of 84.7% by 2% EDTA and XLC gained a desorption rate of 78.9% by 0.1 M HCl. Analysis by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM/EDS) and X-ray photoelectron spectroscopy (XPS) suggested that groups of C–N, COO– for XLA and C–N, CH₂ and phosphate for XLC were the dominant binding sites for Cd²⁺ biosorption. Our results indicated that the fungus XLA, rather than XLC, could potentially be used as an inexpensive, eco-friendly and effective bioremediation agent for the removal of Cd²⁺ from wastewater.     

Urban conservation and revalorisation of dilapidated historic quarters: The case of Nanluoguxiang in Beijing

Property-led urban redevelopment in contemporary Chinese cities often results in the demolition of many historical buildings and neighbourhoods, invoking criticisms from conservationists. In the case of Beijing, the municipal government produced a series of documents in the early 2000s to implement detailed plans to conserve 25 designated historic areas in the Old City of Beijing. This paper aims to examine the recent socio-economic and spatial changes that took place within government-designated conservation areas, and scrutinise the role of the local state and real estate capital that brought about these changes. Based on recent field visits and semi-structured interviews with local residents and business premises in a case study area, this paper puts forward two main arguments. First, Beijing’s urban conservation policies enabled the intervention of the local state to facilitate revalorisation of dilapidated historic quarters and to release dilapidated courtyard houses on the real estate market. The revalorisation was possible with the participation of a particular type of real estate capital that had interests in the aesthetic value that historic quarters and traditional courtyard houses provided. Second, the paper also argues that economic benefits generated by urban conservation, if any, were shared disproportionately among local residents, and that local residents’ lack of opportunities to ‘voice out’ further consolidated the property-led characteristic of urban conservation, which failed to pay attention to social lives.