Itinerary-Dependent Degradation Analysis of a Lithium-Ion Battery Cell for E-Bike Applications in Rwanda

There are obstacles to the widespread use of small electric vehicles(EVs)in Rwanda,including concerns regarding the battery range and lifespan.Lithium-ion batteries(LIBs)play an important role in EVs.However,their performance declines over time because of several factors.To optimize battery management systems and extend the range of EVs in Rwanda,it is essential to understand the influence of the driving profiles on lithium-ion battery degradation.This study analyzed the degradation patterns of a lithium-ion battery cell that propels an E-bike using various real-world E-bike driving cycles that represent Rwandan driving conditions under deep discharge(>80%).By being aware of these variables,battery failure can be slowed and improved battery performance can be achieved to promote the transition to cleaner transportation in Rwanda for the productive use of energy.The analyzed parameters that affect battery performance are temperature,driving cycles,and state of charge.It was found that the higher the temperature,the higher was the rate of fading.On the other hand,the EVs that operate in the region with higher elevation(hilly region)combined with a flat surface where the riders use their physical forces to propel the E-bike and their batteries lose their capacity rapidly compared to those operating in regions where the energy from the lithium-ion battery assists for the entire mileage.By draining the battery to 10%and charging it to 90%of its initial capacity,the capacity fading decreased by 5%.

Seismic design of variable cross-section damped steel support frame for post equipment

High-voltage electrical post equipment is generally installed on steel supports,which amplifies the seismic inputs and degrades the seismic performance of equipment.This study proposed a variable cross-section damped steel support frame(VCDFS)with viscous dampers to reduce seismic responses of both tall and low-rise electrical equipment.The VCDFS contains a trapezoidal damper layer to generate rocking motions,enabling the diagonal viscous dampers to dissipate seismic inputs.A theoretical model of post equipment with VCDFS is established,and an optimal design procedure is proposed.The analysis shows that the remaining static stiffness ratio λ_(k) is the key parameter that determines the effectiveness of the VCDFS.The VCDFS reduces the average displacement and stress response of a post insulator by 39.4%and 44.6%,respectively,together with a significant decrease in the dynamic amplification factor.Therefore,it is recommended to use the VCDFS instead of the conventional latticed-steel frame in earthquake zones.

Dynamic interactive bitwise meta-holography with ultra-high computational and display frame rates

Interactive holography offers unmatched levels of immersion and user engagement in the field of future display.Despite of the substantial progress has been made in dynamic meta-holography,the realization of real-time,highly smooth interactive holography remains a significant challenge due to the computational and display frame rate limitations.In this study,we introduced a dynamic interactive bitwise meta-holography with ultra-high computational and display frame rates.To our knowledge,this is the first reported practical dynamic interactive metasurface holographic system.We spa-tially divided the metasurface device into multiple distinct channels,each projecting a reconstructed sub-pattern.The switching states of these channels were mapped to bitwise operations on a set of bit values,which avoids complex holo-gram computations,enabling an ultra-high computational frame rate.Our approach achieves a computational frame rate of 800 kHz and a display frame rate of 23 kHz on a low-power Raspberry Pi computational platform.According to this methodology,we demonstrated an interactive dynamic holographic Tetris game system that allows interactive gameplay,color display,and on-the-fly hologram creation.Our technology presents an inspiration for advanced dynamic meta-holography,which is promising for a broad range of applications including advanced human-computer interaction,real-time 3D visualization,and next-generation virtual and augmented reality systems.

Cascaded ELM-Based Joint Frame Synchronization and Channel Estimation over Rician Fading Channel with Hardware Imperfections

Due to the interdependency of frame synchronization(FS)and channel estimation(CE),joint FS and CE(JFSCE)schemes are proposed to enhance their functionalities and therefore boost the overall performance of wireless communication systems.Although traditional JFSCE schemes alleviate the influence between FS and CE,they show deficiencies in dealing with hardware imperfection(HI)and deterministic line-of-sight(LOS)path.To tackle this challenge,we proposed a cascaded ELM-based JFSCE to alleviate the influence of HI in the scenario of the Rician fading channel.Specifically,the conventional JFSCE method is first employed to extract the initial features,and thus forms the non-Neural Network(NN)solutions for FS and CE,respectively.Then,the ELMbased networks,named FS-NET and CE-NET,are cascaded to capture the NN solutions of FS and CE.Simulation and analysis results show that,compared with the conventional JFSCE methods,the proposed cascaded ELM-based JFSCE significantly reduces the error probability of FS and the normalized mean square error(NMSE)of CE,even against the impacts of parameter variations.

用“E-Bikes”和“Pedelecs”对电动自行车定义和分类

你也许注意到人力-电动混合型自行车的数量在增加。找出一个合适的名称来区分不同类型的自行车变得越来越困难。至此,你已听到电动自行车(electric bicycles),电动车(e-bikes),电动助力自行车(electric Power Assisted Cycles缩写为EPACs)及电控自行车(Electronic Bike)。你能说出它们之间的区别吗?

荷兰经销商营销e-Bikes获利滚滚

对荷兰经销商而言,e-Bikes（电动自行车）现在是最赚钱的机器。在2010年上半年度,从金钱这方面看,电动自行车成为首屈一指的销售热门。荷兰经销商的电动自行车销售总量占总营业额的37.6%。

Defining the We-map Reference Frames and Providing Mathematical Expressions for Transformation Relations

We-map is an interactive mobile map that can be easily communicated and applied on personal electronic devices,such as personal computers and mobile phones.Therefore,the study of direction systems and coordinate systems is critical,and exploring reference frames is essential in direction and coordinate systems.Despite its significance,existing research on We-map lacks specific solutions for the exploration of reference frames is indispensable for the establishment of accurate direction and coordinate systems.In this paper,we endeavor to address this gap by elucidating the significance of We-map reference frames,defining them with mathematical constraints,summarizing their nature and characteristics,deriving their transformation relationships and representing them through mathematical formulars and equations.Our work contributes to the fundamental theory of We-map and provides valuable systems and support for the mathematical foundation of We-map,map production,and platform development.Ultimately,this research serves to advance the development of We-map.

Resilience-incorporated seismic risk assessment of precast concrete frames with“dry”connections

A resilience-incorporated risk assessment framework is proposed and demonstrated in this study to manifest the advantageous seismic resilience of precast concrete frame(PCF)structures with“dry”connections in terms of their low damage and rapid recovery.The framework integrates various uncertainties in the seismic hazard,fragility,capacity,demand,loss functions,and post-earthquake recovery.In this study,the PCF structures are distinguished from ordinary reinforced concrete frame(RCF)structures by characterizing multiple limit states for the PCF based on its unique damage mechanisms.Accordingly,probabilistic story-wise pushover analyses are performed to yield story-wise capacities for the predefined limit states.In the seismic resilience analysis,a step-wise recovery model is proposed to idealize the functionality recovery process,with separate considerations of the repair and non-repair events.The recovery model leverages the economic loss and downtime to delineate the stochastic post-earthquake recovery curves for the resilience loss estimation.As such,contingencies in the probabilistic post-earthquake repairs are incorporated and the empirical judgments on the recovery parameters are largely circumvented.The proposed framework is demonstrated through a comparative study between two“dry”connected PCFs and one RCF designed as alternative structural systems for a prototype building.The results from the risk quantification indicate that the PCFs show reduced loss hazards and lower expected losses relative to the RCF.Particularly,the PCF equipped with energy dissipation devices at the“dry”connections largely reduces the expected economic loss,downtime,and resilience loss by 29%,56%,and 60%,respectively,compared to the RCF.

Experimental and numerical study regarding H-steel all-bolted connection steel frame with composite wall boards

H-steel all-bolted connection steel frame structures with heat preservation and decoration composite wall boards were investigated and the seismic performances of three scaled specimens were studied.The failure modes,hysteresis curves,bearing capacity,ductility,energy dissipation capacity,stiffness degradation and strain distribution were discussed.The calculation method of structural theoretical internal force was presented.The results showed that the overall structural seismic performance was better,and the structural ductility met the demands of elastic-plastic inter-story drift angle for seismic design.The H-steel weak-axis connection structure obtained better energy dissipation capacity,and its bearing capacity and stiffness were slightly different from the strong-axis connection.The heat preservation and decoration performance of composite wallboard and the all-bolted connection of the steel frame realized prefabrication during the whole construction period.The plastic hinge of the steel beam can be moved outwards because of the L-angles,which effectively avoids stress concentration in joint areas and expands the plastic hinge range.The errors between the theoretical structural capacity calculated by the plastic analysis method and the test results were within 2.44%.In addition,structural failure mechanisms and bearing capacities were verified by the finite element(FE)analysis,and the effects of the main parameters on the structures were investigated.The FE verification results were the same as in the test.The research results provide theoretical support and technical guidance for the application of thermal insulation and decorative composite wall panels in H-shaped steel all-bolted steel frames.

既可电力驱动、又可脚踏骑行的“E-BIKE”电动自行车

富有开拓、创新精神的日本ENAX股份公司（以开发、生产锂电池产品为主业)，通过自身不懈的努力，最近即将向市场推出一款取名为“E-BIKE”的新型折叠式电动自行车。此款“E—BIKE¨技术含金量相当高既可电力驱动，同时又可脚踏骑行．而且操作也相当方便。

Evaluation of the seismic behavior of reinforced concrete structures with flat slab-column gravity frame and shear walls through nonlinear analysis methods

This paper presents an investigation of the seismic behavior of reinforced concrete(RC)structures in which shear walls are the main lateral load-resisting elements and the participation of flat slab floor systems is not considered in the seismic design procedure.In this regard,the behavior of six prototype structures(with different heights and plan layouts)is investigated through nonlinear static and time history analyses,implemented in the OpenSees platform.The results of the analyses are presented in terms of the behavior of the slab-column connections and their mode of failure at different loading stages.Moreover,the global response of the buildings is discussed in terms of some parameters,such as lateral overstrength due to the gravity flat slab-column frames.According to the nonlinear static analyses,in structures in which the slab-column connections were designed only for gravity loads,the slab-column connections exhibited a punching mode of failure even in the early stages of loading.However,the punching failure was eliminated in structures in which a minimum transverse reinforcement recommended in ACI 318(2019)was provided in the slabs at joint regions.Furthermore,despite neglecting the contribution of gravity flat slab-column frames in the lateral load resistance of the structures,a relatively significant overstrength was imposed on the structures by the gravity frames.

Meta databases of steel frame buildings for surrogate modelling and machine learning-based feature importance analysis

Traditionally,nonlinear time history analysis(NLTHA)is used to assess the performance of structures under fu-ture hazards which is necessary to develop effective disaster risk management strategies.However,this method is computationally intensive and not suitable for analyzing a large number of structures on a city-wide scale.Surrogate models offer an efficient and reliable alternative and facilitate evaluating the performance of multiple structures under different hazard scenarios.However,creating a comprehensive database for surrogate mod-elling at the city level presents challenges.To overcome this,the present study proposes meta databases and a general framework for surrogate modelling of steel structures.The dataset includes 30,000 steel moment-resisting frame buildings,representing low-rise,mid-rise and high-rise buildings,with criteria for connections,beams,and columns.Pushover analysis is performed and structural parameters are extracted,and finally,incorporating two different machine learning algorithms,random forest and Shapley additive explanations,sensitivity and explain-ability analyses of the structural parameters are performed to identify the most significant factors in designing steel moment resisting frames.The framework and databases can be used as a validated source of surrogate modelling of steel frame structures in order for disaster risk management.

Structural optimization of a reusable seismic frame active link

Circular design encompasses the use of inventive construction methodologies that possess the capability to be readily dismantled,repurposed,or recycled upon reaching the conclusion of their functional lifespan.This work specifically examines the creation of a reusable design case-study idea for seismic frame design,which is commonly employed in steel-frame constructions in New Zealand.A reusable optimized design for the full seismic frame was proposed in the research.Optimizing the dimensions of welded structures,whether in terms of weight or cost,leads to a decrease in the weight of the steel utilized.The decrease in weight is directly associated with a decrease in environ-mental impact,as the environmental impact is directly proportional to the mass of the construction.The environmental consequences associated with welding technique are contingent upon the dimensions of the weld,hence exerting an indirect influence on the overall mass of the structure.Given the presence of mass dependence in all three areas,albeit in distinct manners,this work employed a multi-objective function optimization strategy to simultaneously address these areas while also partially evaluating them separately.On this way substantial reductions can be achieved both at structural mass and environmental effects.

Field Load Test Based SHM System Safety Standard Determination for Rigid Frame Bridge

The deteriorated continuous rigid frame bridge is strengthened by external prestressing. Static loading tests wereconducted before and after the bridge rehabilitation to verify the effectiveness of the rehabilitation process. Thestiffness of the repaired bridge is improved, and the maximum deflection of the load test is reduced from 37.9 to27.6 mm. A bridge health monitoring system is installed after the bridge is reinforced. To achieve an easy assessmentof the bridge’s safety status by directly using transferred data, a real-time safety warning system is createdbased on a five-level safety standard. The threshold for each safety level will be determined by theoretical calculationsand the outcomes of static loading tests. The highest risk threshold will be set at the ultimate limit statevalue. The remaining levels, namely middle risk, low risk, and very low risk, will be determined usingreduction coefficients of 0.95, 0.9, and 0.8, respectively.

Frame Length Dependency for Fundamental Frequency Extraction in Noisy Speech

The fundamental frequency plays a significant part in understanding and perceiving the pitch of a sound. The pitch is a fundamental attribute employed in numerous speech-related works. For fundamental frequency extraction, several algorithms have been developed which one to use relies on the signal’s characteristics and the surrounding noise. Thus, the algorithm’s noise resistance becomes more critical than ever for precise fundamental frequency estimation. Nonetheless, numerous state-of-the-art algorithms face struggles in achieving satisfying outcomes when confronted with speech recordings that are noisy with low signal-to-noise ratio (SNR) values. Also, most of the recent techniques utilize different frame lengths for pitch extraction. From this point of view, This research considers different frame lengths on male and female speech signals for fundamental frequency extraction. Also, analyze the frame length dependency on the speech signal analytically to understand which frame length is more suitable and effective for male and female speech signals specifically. For the validation of our idea, we have utilized the conventional autocorrelation function (ACF), and state-of-the-art method BaNa. This study puts out a potent idea that will work better for speech processing applications in noisy speech. From experimental results, the proposed idea represents which frame length is more appropriate for male and female speech signals in noisy environments.

Real-Time Mosaic Method of Aerial Video Based on Two-Stage Key Frame Selection Method

A two-stage automatic key frame selection method is proposed to enhance stitching speed and quality for UAV aerial videos. In the first stage, to reduce redundancy, the overlapping rate of the UAV aerial video sequence within the sampling period is calculated. Lagrange interpolation is used to fit the overlapping rate curve of the sequence. An empirical threshold for the overlapping rate is then applied to filter candidate key frames from the sequence. In the second stage, the principle of minimizing remapping spots is used to dynamically adjust and determine the final key frame close to the candidate key frames. Comparative experiments show that the proposed method significantly improves stitching speed and accuracy by more than 40%.

RC Frame-Prefabricated HPFRCC Energy Wall Structure System Energy Distribution Research

The weak layer of steel concrete (RC) frame structure is easy to destroy under the action of the earthquake, the damage mechanism is more difficult to control. Severe damage to the building structure after the earthquake, resulting in too high repair costs or having to dismantle and rebuild. In order to improve and enhance the anti-seismic performance of the RC framework structure, energy consumption devices are added between the frame columns to achieve the effect of reducing the RC frame structure damage and improving the seismic performance of the RC frame structure. In this article, high-performance fiber-enhanced cement base composite materials fabricated energy consumption walls are prepared in the RC frame structure to form a new type of seismic structure system of RC frame-prefabricated HPFRCC energy consumption wall. This article uses the power timing analysis of the ABAQUS finite element software to study the anti-seismic performance, influencing factors and energy consumption distribution of the RC frame-prefabricated HPFRCC energy wall structural system.

远程开放教育中移动学习的接受与学习体验探究——基于COI和FRAME综合模式的考察

随着智能手机的普及、移动互联网的发展和云平台的应用,移动学习已成为我国远程开放教育普遍采用的学习形式,移动学习的接受和学习体验成为亟待研究的课题。本研究借鉴西方移动学习理论,通过批判性综合探究社区理论(COI)和移动学习理性分析框架(FRAME),进行问卷调查。结果表明,远程开放教育移动学习的教学设计需要充分考虑设备维度的限制,加强内容碎片化和输入方式多元化设计,增强移动学习交流与互信,提升合作学习探究效果,加强导学课或线上学习素养课的实施。远程开放教育需要面对新的移动社会的变化,持续思考,更新、优化、整合教育系统,以进一步激发学习者在移动学习中发挥、利用、实现自己的潜能。

基于性能谱设计的被动消能减震结构易损性分析

建设韧性城市的实质是实现城市灾后的可修复和自修复功能,消能减震技术为提高城市韧性、实现可持续发展提供了新思路。基于性能谱设计方法,提出一种适用于中低层框架结构的减震设计方法,将结构阻尼参数、响应及地震动参数结合起来,通过改变结构性能参数达到控制其响应的目的;并采用该方法对一6层Benchmark钢框架结构进行减震设计,对比分析在远场和近场有、无明显脉冲地震动记录下,减震设计前后结构不同损伤状态下的易损性。结果表明:在弹性阶段,近场非脉冲和脉冲型地震动记录下的结构响应基本一致,且略大于远场地震动记录下;在弹塑性至倒塌阶段,近场非脉冲型地震动记录下的结构响应大于远场地震动记录下;相比于远场和近场非脉冲型地震动记录,近场脉冲型地震动记录更容易引起结构的破坏甚至倒塌。基于性能谱减震设计方法设计的结构,其抗倒塌能力在远场、近场非脉冲和近场脉冲型地震动记录下分别提高了44.8%、43.8%和45.6%,进一步说明该减震设计方法受地震动记录的影响非常小。

地震动持时对双层高架桥框架式桥墩抗震性能评价的影响

为研究地震动持时对双层高架桥框架式桥墩抗震性能评价的影响,基于双层框架式桥墩的拟静力试验,借助OpenSees有限元软件建立数值模型,将模拟结果与试验结果进行对比,两者吻合较好。选取两组具有长、短持时特性的地震动记录,通过增量动力分析(IDA)建立峰值地面加速度(PGA)与位移延性比u的关系,得到易损性曲线。长持时地震动作用下PGA中位值为0.35g、0.55g、0.78g、0.98g,短持时地震动作用下PGA中位值为0.35g、0.59g、0.91g、1.20g。随着损伤程度的加大,双层框架式桥墩易损性曲线的差异区间随着PGA的增大而增大;9度(0.40 g)罕遇地震时,长、短持时地震动作用下双层框架式桥墩发生严重损伤和完全破坏的概率分别为25.57%、8.61%和16.98%、4.79%,说明当PGA较大时,双层框架式桥墩在长持时地震动作用下更容易受到损伤。