Development of Five-Finger Multi-DoF Myoelectric Hands with a Power Allocation Mechanism

To be used as five-fingered myoelectric hands in daily living, robotic hands must be lightweight with the size of human hands. In addition, they must possess the DoFs （degrees of freedom） and high grip force similar to those of human hands. Balancing these requirements involves a trade-off; ideal robotic hands have yet to sufficiently satisfy both requirements. Herein, a power allocation mechanism is proposed to improve the grip force without increasing the size or weight of robotic hands by using redundant DoFs during pinching motions. Additionally, this mechanism is applied to an actual five-fingered myoelectric hand, which produces seven types of motions necessary for activities of daily living and realizes a -60% improvement in fingertip force, allowing three fingers to pinch objects exceeding 1 kg.

多指手Power抓持的鲁棒性分析及稳定载荷域计算

分析了多指手Power抓持可被动抵抗外部载荷扰动影响的性质 ,给出具有一般意义的抓持鲁棒性定义。基于抓持接触力空间的分解及接触力空间与外力空间的映射关系 ,将外力空间分解为主动平衡外力子空间及被动平衡外力子空间 ,给出抓持系统具有鲁棒性质的充分必要条件。针对Power抓持鲁棒性的定量描述 ,提出一种确定抓持稳定载荷域的有效算法。

Effects of steep-axis incision on corneal curvature in onehanded phacoemulsification

AIM: To examine the effects of one-handed phacoemulsification with steep-axis incision on corneal curvature and analyze surgically induced astigmatism(SIA) on the true net power, anterior and posterior corneal surfaces. METHODS: Patients with cataracts underwent onehanded phacoemulsification with a 2.4-mm steep-axis of clear corneal incision(CCI) based on true net power. CCI was created under the guidance of Verion. Central corneal thickness(CCT), keratometry readings of the true net power and anterior and posterior corneal surface were obtained using Pentacam. Biometry, such as axial length, anterior chamber depth(ACD) and white-to-white(WTW) were performed using Lenstar pre-and 3 mo postoperatively. RESULTS: The study evaluated 68 eyes of 65 patients. The mean age was 65.93±9.40 y;CCT was 529.21±37.40 μm;WTW was 11.59±0.35 mm. Regarding true net power, keratometric value at the flattest corneal meridian for the 3-mm central zone(Ks) was significantly decreased postoperatively(P=0.031). Keratometric value at the steepest corneal meridian for the 3-mm central zone(Kf) was increased postoperatively(P>0.05). Astigmatism of true net power was 1.21±0.56 D preoperatively and significantly decreased to 1.02±0.58 D postoperatively(P=0.021). On the anterior corneal surface, no significant difference in Ks and Kf was noted pre-versus postoperatively. Anterior corneal astigmatism was 1.08±0.51 D preoperativelyand significantly decreased to 0.87±0.46 D postoperatively(P=0.002). On the posterior corneal surface, Ks and Kf were significantly increased postoperatively(all P<0.05), and posterior corneal astigmatism also increased(P=0.008). The SIA values of true net power and the anterior and posterior corneal surfaces at 3 mo postoperatively were 1.26±0.63 D(range: 0.11 to 2.80 D), 1.05±0.54 D(range: 0.23 to 2.40 D), and 0.21±0.17 D(range: 0.01 to 0.07 D), respectively. CONCLUSION: One-handed phacoemulsification with steep-axis incision can effectively decrease astigmatism of true net power and anterior corneal astigmatism. In the same surgery, the difference in personal SIA potentially originated from a difference in personal corneal thickness and diameter, both CCT and WTW distance should always be measured preoperatively when planning steep-axis phacoemulsification.

TE Modal Dispersion in Dielectric Slab Waveguide with Lossy Left-Handed Metamaterial

In this work, we derived the modal dispersion relation for TEm modes for a symmetric slab waveguide constructed from SiO2 dielectric guiding core material with lossy left-handed material (LHM) as cladding and substrate, and the power confinement factor. The dispersion relations and the power confinement factor were numerically solved for a given set of parameters: allowed frequency range;core’s thicknesses;and TEm mode order. We found that the real part of the effective refractive index decreased with thickness and frequency increase. Moreover, the imaginary part (extinction coefficient) of the effective refractive index has very small values for all thickness in the frequency ranges, which means the waveguide structure is transparent for the used frequencies. The waveguide structure offers good guiding power for all thickness in the frequency range with low power attenuation. The real part of the effective refractive index increases with the increase of mode order, and the power confinement factor decreases with the increase of mode order.

Helping Hands

A potato farmer was sent to prison just at the timewhen he should have been digging the ground for plantingthe new crop of potatoes. He knew that his wife wouldnot be strong enough to do the digging by herself, butthat she could manage to do the pianting; and he alsoknew that he did not have any friends or neighbours whowould be willing to do the digging for him. So he

Analytical Approach of the Nonlinear Surface Plasmon at a Left-Handed Material

The surface wave dispersion relations of surface Plasmon at the interface of a left-handed material and a non-linear Kerr medium of arbitrary nonlinearity are derived based on a generalized first integral approach. The normalized power flow is also investigated for various values of frequency. The above study is conducted for both cases: self-focusing (α&prec;0) and de-focusing (α&succ;0) nonlinear Kerr coefficient.

Usefulness of a Newly-Developed Device, the Power Tree^(■), for Body Massage: Evidence from a Medical Evaluation

We investigated the effectiveness and usefulness of a novel tool: the Power Tree?, for body massage in 10 healthy female volunteers (age range, 24 - 55 years;mean age, 40.5 years) by evaluating several dermatological and psychological parameters, such as the amount of dermal collagen, the skin temperature, the level of salivary amylase and the scores on the State-Trait Anxiety Index (STAI). After 60-minute Power Tree?-mediated body massage, both the dermal collagen score determined from the DermaLab? images and skin temperature measured by infrared thermography were found to have increased significantly in several body sites compared to those before the treatment (p < 0.01 and p < 0.001, respectively). Although the level of stress estimated by the amount of amylase in the saliva was not significantly different pre- and post-procedure (p = 0.3), the treatment significantly reduced both the state anxiety (SA) and trait anxiety (TA) scores on the STAI (p < 0.001 for the SA, p < 0.01 for the TA). The treatment with this device was smoothly performed without any burden on the therapists during the present study. These data suggest that the newly-developed device is a powerful and useful tool for reflexology when used for full body massage therapy, and massage therapy using this device may produce beneficial, physiological effects as well as psychosocial improvements.

Effect of negative permittivity and permeability on the transmission of electromagnetic waves through a structure containing left-handed material

We investigate the characteristics of electromagnetic wave reflection and transmission by multilayered structures consisting of a pair of left-handed material (LHM) and dielectric slabs inserted between two semi-infinite dielectric media. The theoretical aspect is based on Maxwell's equations and matching the boundary conditions for the electric and magnetic fields of the incident waves at each layer interface. We calculate the reflected and transmitted powers of the multilayered structure taking into account the widths of the slabs and the frequency dependence of permittivity and permeability of the LHM. The obtained results satisfy the law of conservation of energy. We show that if the semi-infinite dielectric media have the same refractive index and the slabs have the same width, then the reflected (and transmitted) powers can be minimized (and maximized) and the powers-frequency curves show no ripple. On the other hand if the semi-infinite dielectric media have different values of refractive indices and the slabs have different widths, then under certain conditions the situation of minimum and maximum values of the mentioned powers will be reversed.

Guided Modes in a Four-Layer Slab Waveguide with Dispersive Left-Handed Material

A four-layer slab waveguide including left-handed material is investigated numerically in this paper. Considering left-handed material dispersion, we find eight TE guided modes as frequency from 4 GHz to 6 GHz. The fundamental mode can exist, and its dispersion curves are insensitive to the waveguide thickness. Besides, the total power fluxes of TE guided modes are analyzed and corresponding new properties are found, such as: positive and negative total power fluxes coexist;at maximum value of frequency, we find zero total power flux, etc. Our results may be of benefit to the optical waveguide technology.

基于知识图谱的端到端内容共享机制

端到端(D2D)通信利用边缘网络的本地计算和缓存能力,可以满足未来移动网络用户低延时、高能效的内容共享需求。而边缘网络内容共享效率性能的提升不仅取决于用户社交关系,同时也高度依赖终端设备的特征,如计算、存储和剩余能量资源等。因此,以最大化能量效率为目标,综合考虑设备异质性、用户社交性和兴趣差异性,提出一种用户-设备-内容多维度关联特征的D2D内容共享机制。首先,基于用户成本效益最大化将多目标约束问题转化为最优节点选择和功率控制问题,构建面向用户-设备-内容的多维度知识关联特征和图谱模型,将设备相关的计算资源、存储资源等多维特征结构化处理;其次,研究用户在设备属性和社交属性上的意愿度度量方法,提出一种基于用户社交和设备图谱的共享意愿度度量方法;最后,根据用户共享意愿度构建面向内容共享的D2D协作簇,面向能量效率设计一种基于共享意愿度的功率控制算法,以最大化网络共享性能。在真实用户设备数据集和infocom06数据集的实验结果表明,所提基于共享意愿度的功率控制算法与最近选择算法和不考虑设备意愿度的选择算法相比,系统和速率分别提升了约97.2%和11.1%,用户满意度分别提升了约72.7%和4.3%,能效分别提升了约57.8%和9.7%,验证了所提算法在传输速率、能量效率和用户满意度等方面的有效性。

新型手抛式输电线路接地线的研究

为适应超特高压输电线的快速发展和检修工作的需要,解决输电耐张塔内转角挂接困难的问题,结合现场工作实际,设计出一种手抛式接地线。对比传统已有的2种接地工具的弊端,提出新型接地线夹结构,通过机械设计连接,在接地线夹领域首次实现单方向受力双段控制线夹完成接地线的远距离抛挂及拆除。通过现场实地1∶1输电塔挂拆试验,顺利完成挂接,经过安全检测后已量产。根据电力生产需要,利用上述机械线夹结构思想,变更相应线夹尺寸、配置不同长度和截面接地铜线,将能应用于多种电压等级的输电线路接地。

医学生“学习强国”学习平台使用情况分析——以广西某医学院校为例

为了分析影响医学生“学习强国”学习平台使用情况的相关因素,提出高校网络思想政治教育优化建议。通过拟合优度检验分析用户行为,通过卡方检验、二元Logistic回归分析讨论平台用户特征。结果显示,医学生“学习强国”学习平台使用概率较低,但平台教育意义认可度较高;中共党员、非医学类专业医学生为平台常用人群;医学生用户偏好于平台学习教育功能,以及政策法律等内容。因此,可以通过环境营造、“校师生”要素联动及学生需求探索,形成用户有效激励。

基于温控负荷参与的多虚拟电厂联合调度研究

空调等温控负荷在虚拟电厂(VPP)的优化调度中起着至关重要的作用。针对VPP中新能源功率输出不稳定问题,提出了基于温控负荷参与的多VPP联合调度策略。首先,研究了温控负荷聚合模型,构建了多VPP分布式能源协调互补的联合调度框架,在日前阶段根据预测数据制定联合调度计划,多VPP管理中心对各VPP进行多能互补。其次,在日前阶段引入考虑用户意愿度的温控负荷模型,在日内阶段根据短期预测数据对调度计划进行滚动修正,减少新能源功率输出波动带来的供需偏差。最后,通过MATLAB调用Cplex仿真分析,验证了多VPP联合优化调度策略不仅保证了供电可靠性,还有效减少了预测偏差带来的补偿费用。

Hand Gesture-based Artificial Neural Network Trained Hybrid Human–machine Interface System to Navigate a Powered Wheelchair

Individuals with cerebral palsy and muscular dystrophy often lack fine motor control of their fingers which makes it difficult to control traditional powered wheelchairs using a joystick.Studies have shown the use of surface electromyography to steer powered wheelchairs or automobiles either through simulations or gaming controllers.However,these studies significantly lack issues with real world scenarios such as user’s safety,real-time control,and efficiency of the controller mechanism.The purpose of this study was to design,evaluate,and implement a hybrid human–machine interface system for a powered wheelchair that can detect human intent based on artificial neural network trained hand gesture recognition and navigate a powered wheelchair without colliding with objects around the path.Scaled Conjugate Gradient(SCG),Bayesian Regularization(BR),and Levenberg Marquart(LM)supervised artificial neural networks were trained in offline testing on eight participants without disability followed by online testing using the classifier with highest accuracy.Bayesian Regularization architecture showed highest accuracy at 98.4%across all participants and hidden layers.All participants successfully completed the path in an average of 5 min and 50 s,touching an average of 22.1%of the obstacles.The proposed hybrid system can be implemented to assist people with neuromuscular disabilities in near future.

考虑电动汽车集群响应的分布式资源协同调度策略研究

在国家政策的大力推动下,分散式风电大规模并网,给河南乡村配电网运行带来严峻挑战。为充分调动电动汽车(electric vehicle,EV)群需求响应及小型抽水蓄能灵活性资源参与电网协同调度,采用Takagi-Sugeno-Kang(TSK)模糊模型量化电动汽车群的响应意愿,以明确电动汽车集群充电功率的可调节裕度。在此基础上,提出一种计及电动汽车响应不确定性的风电-电动汽车群-小型抽水蓄能协同运行模型,以弃风惩罚和激励成本最小为目标函数引导电动汽车及抽水蓄能参与功率调节。基于信阳某乡村地区10kV配电系统,验证了考虑电动汽车响应意愿对促进风电消纳和提升运行经济性的有效性,以及与小型抽水蓄能共同形成“风-储-荷”运行的协同效果。

大单边供电在地铁故障处置及运营组织中的运用分析

众所周知,及时处置供电故障、恢复正常运营,是保证地铁安全、可靠运行的关键,目前,电力系统主要通过大单边或大双边的方式供电,与大双边供电相比,大单边供电的发生频率较低,但对调度员能力的要求更加严格。鉴于此,文章从处置地铁故障、运营组织出发,围绕大单边供电的运用展开了讨论,在介绍该技术所能发挥作用的前提下,系统总结了处置停电故障、运营组织的原则与方法,希望能够给有关人员以启发。

连云港公众对核电和火电风险感知的比较分析

研究造成不同人群对核电和火电风险感知差异的关键因素,并分析不同人群对这2种风险支付意愿(WTP)的差别。采用公众问卷调研法及多元统计法分析公众对核电和火电的风险感知。结果表明,年龄为30～39岁的人群以及教育程度为大专和研究生学历的人群对核电和火电的风险感知差别度具有显著差异性,同时也发现政府在人们对比核电和火电风险感知程度时扮演重要角色,即对政府信任度高的人对核电的风险感知度相对较低。风险支付意愿分析表明,不同分类人群对核电和火电风险的WTP值总体趋势一致,即女性高于男性,低龄组和高龄组高于中龄组,无业者和家庭主妇高于有固定职业者,受中等教育者高于受低等和高等教育者,30 000～50 000元年薪者高于其他年薪段人,外地游客高于移居者和本土居民。本研究为政府等决策机构选择有效目标人群提供了参考依据。

基于输电当量电价的直接阻塞管理

输电网阻塞本质上是反映线路传输容量之不足。基于传统的短期边际成本方法所给出的阻塞电价信号不足以反映输电线路容量之不足。针对这一问题,文章在输电当量电价模型的基础上,引入“支付意愿”概念,建立了阻塞管理模型。该模型能在利用电价调控阻塞无能为力的情况下合理地削减负荷,同时又承袭了输电当量电价充分回报容量投资,充分而又合理地积累电网扩建资金的特性,从而比较好地解决了阻塞管理问题。此外,还允许用户参与阻塞管理,还增进了市场效率和公正性。算例结果表明,该方法能有效地解决输电网的阻塞问题。

农业秸秆综合利用中农户意愿和行为研究

为应对能源短缺和气候变化,我国大力发展生物质发电产业。但由于缺乏充足的燃料,许多生物质发电企业处于亏损状态。农户对农业秸秆供应的意愿和行为是影响秸秆收集利用的关键。利用因子分析法识别影响农户意愿和行为的主要因素,继而用Logistic模型分别探讨这些因素对意愿和行为的影响。研究结果表明,这些影响因素对农户秸秆供应意愿和行为具有不同的影响力,分析结果为促进意愿到行为的转化提供了依据。为提高农户秸秆供应意愿和行为,本文提出了全新的秸秆收集模式,用Logistic模型分析了该模式对农户意愿的影响机制。

上海市徐汇区儿童家长对EV71疫苗接种意愿及Logistic影响因素分析

目的 了解上海市徐汇区5岁及以下儿童家长对手足口病EV71疫苗接种意愿及影响因素,为更好推广EV71疫苗接种提供决策信息。方法 采用整群抽样在徐汇区13个社区预防接种门诊,每家随机抽取72名5岁及以下儿童家长,通过手机扫描二维码对EV71疫苗接种情况等方面进行问卷调查,采用SPSS 20.0软件进行单因素和Logistic多因素分析。结果 共调查943名5岁及以下儿童家长,其中未接种疫苗儿童537名(56.95%);在未接种组中71.69%家长有意愿为孩子接种,73.18%家长知道EV71疫苗;51.40%家长知晓疫苗只预防EV71型手足口病;接种EV71疫苗后仍有可能感染手足口病,仍愿意为孩子接种64.62%(347/537);接种意愿多因素Logistic回归显示:儿童年龄(OR=0.32,95%CI:0.11~0.96)、家长知晓手足口病除EV71外还有其他病原体(OR=2.49,95%CI:1.22~5.08)、疫苗只预防EV71型手足口病但仍愿意接种(OR=0.02,95%CI:0.01~0.03)、通过互联网、微信等获取手足口病和疫苗相关知识(OR=0.41,95%CI:0.21~0.79)是接种意愿的影响因素。结论 手足口病EV71疫苗接种率较低,接种意愿较高,受儿童年龄、知晓手足口病和疫苗相关知识、获取知识途径的影响,因此健康教育须有针对性,以提高其接种率,降低发病率。